CUSHIONING CONVERSION MACHINE INCLUDING A LENGTH MEASURING DEVICE

Abstract: The cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a controller for controlling operation of the feed assembly to produce a pad of a predetermined length, and a pad-length measuring device. The pad-length measuring device may include a device for measuring the length, weight, radius or height of paper removed or unwound from a supply, or a device for measuring the length or weight of a pad as it is produced.

Description: Title: CUSHIONING CONVERSION MACHINE INCLUDING A LENGTH MEASURING DEVICE FIELD OF THE INVENTION This invention relates generally as indicated to a cushioning conversion machine including a measuring device for measuring or approximating the length of cushioning product produced by the machine. More particularly, the present invention relates to a cushioning conversion machine including a length measuring device and a controller which cooperatively produce a controlled length of cushioning material in accordance with a length input. BACKGROUND OF THE INVENTION In the process of shipping an item from one location to another, a protective packaging material is typically placed in the shipping container to fill any voids and/or to cushion the item during the shipping process. Some commonly used protective packaging materials are plastic foam peanuts and plastic bubble pack. While these conventional plastic materials seem to perform adequately as cushioning products, they are not without disadvantages. Perhaps the most serious drawback of plastic bubble wrap and/or plastic foam peanuts is their effect on our environment. Quite simply, these plastic packaging materials are not biodegradable and thus they cannot avoid further multiplying our planet's already critical waste disposal problems. The non-biodegradability of these packaging materials has become increasingly important in light of many industries adopting more progressive policies in terms of environmental responsibility. These and other disadvantages of conventional plastic packaging materials have made paper protective packaging material a very popular alterative. Paper is biodegradable, recyclable and renewable; making it an environmentally responsible choice for conscientious companies. While paper in sheet form could possibly be used as a protective packaging material, it is usually preferable to convert the sheets of paper into a low density cushioning product. This conversion may be accomplished by a cushioning conversion machine, such as those disclosed in U.S. Patent Nos. 4,026, 1 98; 4,085,662; 4, 1 09,040; 4,237,776; 4,557,71 6; 4,650,456; 4,71 7,61 3; 4,750,896; and 4,968,291 . (These patents are all assigned to the assignee of the present invention and their entire disclosures are incorporated herein by this reference.) Such a cushioning conversion machine converts sheet-like stock material, such as paper in multi-ply form, into low density cushioning pads. A cushioning conversion machine, such as those disclosed in the above-identified patents, may include a stock supply assembly, a forming assembly, a gear assembly, and a cutting assembly, all of which are mounted on the machine's frame. During operation of such a cushioning conversion machine, the stock supply assembly supplies the stock material to the forming assembly. The forming assembly causes inward rolling of the lateral edges of the sheet-like stock material to form a continuous strip having lateral pillow-like portions and a thin central band. The gear assembly pulls the stock material through the machine and also coins the central band of the continuous strip to form a coined strip. The coined strip travels downstream to the cutting assembly which cuts the coined strip into pads of a desired length. Typically, the cut pads are discharged to a transitional zone and then, either immediately or at a later time, inserted into a container for cushioning purposes. With particular reference to the gear assembly, it includes loosely meshed gears between which the unconnected strip travels . The drive gear is fixedly mounted to a rotating shaft which is coupled to a motor. During operation of the machine, the gear motor rotates the shaft (and thus the drive gear) in an appropriate direction whereby the central band of the strip is grabbed by the gear teeth and pulled downstream through the nips of the gears. Thus, the gear assembly is a rotating conversion assembly which determines the production rate of the coined strip and, therefore, the cushioning products, or pads. (This "grabbing" simultaneously coins the layers of the central band together to form the coined strip.) By selectively controlling the gear assembly (i.e. , by activating/deactivating its motor) and the cutting assembly, a cushioning conversion machine can create pads of a variety of lengths. This feature allows a single machine to satisfy a wide range of cushioning needs. For example, relatively short pad lengths can be employed in connection with small and/or unbreakable articles, while longer pad lengths can employed in connection with larger and/or fragile articles. Moreover, a set of pads (either of the same or different lengths) can be employed in connection with uniquely shaped and/or delicate articles, such as electronic equipment. Presently, a variety of length-controlling systems are used to control pad length. For example, a manual system is available in which a packaging person manually activates the gear assembly (i.e. , steps on a foot pedal) for a time period sufficient to produce a coined strip of the desired length. He/she then manually deactivates the gear assembly (i.e. , releases the foot pedal) and activates the cutting assembly (i.e. , pushes an appropriate button on the machine's control panel) to cut the coined strip. In this manner, a pad of the desired length is created. Alternatively, the system is designed so that a manual deactivation of the gear assembly (i.e., release of the foot pedal) automatically activates the cutting assembly. Another technique used to control pad length is a time-repeat system. In such a length-controlling system, a timer is electrically connected to the gear assembly. The timer is set for a period (i.e. , seconds) which, based on an estimated gear velocity, corresponds to the desired length of the pad . The time-repeat system is designed to automatically activate the gear assembly for the selected period and thereby, assuming the estimated gear velocity is correct and constant, produce a coined strip of the desired length. The system then deactivates the gear assembly and activates the cutting assembly to cut the coined strip into a first pad of the desired length. Thereafter, the system automatically re-activates the gear assembly to repeat the cycle so that, if the timer has not been reset, a multitude of pads of substantially the same length are continuously created. A further available length-controlling system is a removal-triggered system. This system is similar to the time-repeat system in that it deactivates the gear assembly based on the setting of a timer. However, with the removal-triggered system, the gear assembly is not automatically reactivated. Instead, it is only re-activated when the cut pad is removed, either manually by the packaging person or mechanically by a conveyor. Upon reactivation, another pad of the same length is produced unless the timer is reset. Yet another length-controlling system includes a length-selection system which allows a packaging person to select certain predetermined pad lengths. In such a system, a selection panel (e.g. , a key pad) is provided with a plurality of length options (e.g., buttons) so that a packaging person can manually select the appropriate pad length. When a particular length option is selected, the gear assembly is automatically activated for a period of time (based on estimated gear velocity) corresponding to the selected pad length. At the expiration of this time period, the gear assembly is deactivated, and the cutter assembly is activated. The process is then repeated and, unless another length option is manually selected, a subsequent pad of the same length is produced. In many packaging situations, the production of a single pad length is sufficient to satisfy cushioning requirements and the above-discussed automatic controlling systems are usually compatible with these situations . For example, with a time-repeat system and/or a removal-triggered system, the packaging person manually sets the timer at a period corresponding to the desired length and a plurality of pads of this length are produced . Likewise, with a length-selection system, the packaging person manually selects the desired length option and a plurality of pads of the selected length are produced. In other packaging situations, however, single pad length production is insufficient to satisfy cushioning requirements. For example, a series of identical packaging jobs may each require a set of pads of different lengths. Alternatively, a series of widely varying packaging jobs may each require a single pad, but each job may need a different sized pad. Also, a series of non-identical packaging jobs may each require a different set of pads of varying lengths. The non-manual length controlling systems sometimes do not adequately accommodate these latter packaging situations. Specifically, in order to sequentially produce pads of different lengths, the timer on a time-repeat systems and/or a removal-triggered system must be manually reset after each pad. Likewise, if a length-selection system is used, the packaging person must continuously manually change the length option. Thus, a high degree of interaction with the cushioning conversion machine is necessary. Therefore, in order for a packaging person to properly interact with the machine, at least minimal training is necessary. Additionally, while the packaging person is interacting with the machine, he/she is not packaging thereby hindering the overall efficiency of the packaging program. Regarding the manual length-controlling system, it can certainly be used to sequentially produce pads of different lengths. However, again, a high degree of interaction is necessary thereby requiring trained personnel and/or thereby hindering efficiency. Moreover, in both the manual and non-manual length-controlling systems, the packaging person must determine (either by experience or experiment) the appropriate pad length. For this additional reason, the use of untrained workers in sophisticated packaging situations is often impractical. Accordingly, applicant appreciated that a broader range of length measuring devices was necessary to accommodate a full range of packaging situations. SUMMARY OF THE INVENTION In accordance with one aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a roller which rolls along the stock material as it is fed from the supply roll and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to approximate the length of cushioning material produced as a function of the rotation of the roller. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a probe which contacts a point on the outer radius of the supply roll and a position sensor which senses the position of the probe relative to a known point and which communicates the position of the probe to the controller to approximate the length of cushioning product produced as a function of the change in the radius of the stock supply roll. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stack of generally fan-folded stock material through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a probe which contacts the stack of stock material and a position sensor for sensing the position of the probe and communicating the position of the probe to the controller to approximate the length of cushioning product produced as a function of the change in the height of the stack of supply material. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stack of generally fan-folded stock material through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a sensor which senses the removal of a fold of paper beneath the probe and communicates the removal to the controller to approximate the length of cushioning product produced as a function of the removal of folds of stock material from the stack of stock material. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a sensor for detecting the occurrence of indicia recorded on the stock material as the material is fed past the sensor and for communicating the detection of the occurrence of the indicia to the controller to approximate the length of cushioning product produced as a function of the number of indicia detected. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a light transmitter for directing light incident on the stock material and a light detector for detecting the occurrence of perforations in the stock material as a function of reflected light as the material is fed past the sensor and for communicating the detection of the occurrence of the perforations to the controller to approximate the length of cushioning product produced as a function of the number of perforations detected. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including scale for measuring the weight of the stock supply roll and for communicating the weight of the stock supply to the controller to approximate the length of cushioning product produced as a function of the change in weight of the stock supply. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined weight, and a weight measuring device including scale for measuring the weight of the supply roll and for communicating the weight of the roll to the controller to cause the feed motor to stop when the change in the measured weight reaches the predetermined weight. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly; and a length measuring device including a unwinder for unwinding a desired length of stock material from the roll, and a sensor switch for indicating the presence of stock material unwound from the roll and for causing the feed assembly to feed stock material through the forming assembly while the sensor detects the presence of unwound stock material . In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller, and a length measuring device including an unwinder for unwinding a desired length of stock material from the roll and a linear array of sensors, each sensor of the array for detecting the presence of stock material adjacent the sensor and communicating such detection to the controller, and wherein the controller controls the unwinder and the feed assembly in accordance with the communications from the linear array of sensors to produce a cushioning product of a predetermined length. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a severing assembly for severing the stock material fed through the conversion assembly to form a discrete cushioning product, and a length measuring device including a reticle permitting the measurement of stock material manually unwound from the supply roll, and a sensor switch for indicating the presence of stock material unwound from the roll and for causing the feed assembly to feed stock material through the forming assembly while the sensor detects the presence of unwound stock material. The sensor switch may cause the severing assembly to sever the stock material after the sensor detects the absence of unwound stock material. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly powered by a feed motor for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a pump powered by the feed motor for generating pressurized air, a reservoir for accumulating the pressurized air and a pressure sensor which senses the level of pressure in the reservoir and a switch for communicating to the controller the occurrence of the sensed pressure reaching a value which corresponds to the predetermined length of cushioning product to be produced. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly powered by a feed motor for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a pump powered by the feed motor for introducing fluid to a reservoir and a level sensor which senses the level of fluid in the reservoir and a switch for communicating to the controller the occurrence of the sensed level reaching a value which corresponds to the predetermined length of cushioning product to be produced. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly powered by a stepper motor for feeding stock material from a stock supply roll through the forming assembly, a length input device permitting the entry by an operator of a desired length of cushioning material to be produced, and a controller for controlling operation of the stepper motor through pulses generated in accordance with the desired length entered through the length input device. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a feed motor for powering the feed assembly, a clutch assembly for selectively engaging the feed assembly with the feed motor to cause a specified length of cushioning product to be fed through the forming assembly, and a controller for controlling operation of the clutch assembly. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly powered by a feed motor for feeding stock material from a stock supply through the forming assembly, a power sensor for sensing the amount of power supplied to the feed motor, a length input device permitting the entry by an operator of a desired length of cushioning product to be produced, and a controller for correlating the desired length of cushioning product to be produced to the required amount of power necessary to supply to the feed motor for it to feed the appropriate length of stock material through the forming assembly to produce the desired length of cushioning product and for controlling the supply of power to the feed motor in accordance with the length of cushioning product to be produced and the cumulative amount of power supplied to the feed motor as sensed by the power sensor. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a severing assembly for severing the continuous strip of cushioning product into a discrete length of cushioning product, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length; and a length measuring device including a roller which rolls along the cushioning product after it is formed and prior to being severed, and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to determine the length of cushioning material produced as a function of the rotation of the roller. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a severing assembly for severing the continuous strip of cushioning product into a discrete length of cushioning product a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length; and a length measuring device including a roller which rolls along the cushioning product downstream of the severing assembly, and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to determine the length of cushioning material produced as a function of the rotation of the roller. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, an assembly for forming indicia on the cushioning product, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length; and a length measuring device including a sensor which detects the occurrence of indicia on the cushioning material and which communicates such occurrences to the controller to determine the length of cushioning material produced as a function of the number of occurrences of indicia detected . The indicia may be printed on the cushioning product as it is formed. Alternatively, the indicia may include perforations made in the cushioning product as it is formed. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly and through an output of the machine, a controller, and a length measuring device including a linear array of sensors arranged at the output of the machine, each sensor of the array for detecting the presence of different lengths of cushioning product and communicating such detection to the controller, and wherein the controller controls the feed assemblv in accordance with the communications from the linear array of sensors to produce a cushioning product of a predetermined length. In accordance with one aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, the feed assembly including at least one rotating component, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a velocity sensor for sensing the velocity of the rotating component and communicating the velocity to the controller to calculate the length of cushioning product produced as a function of integral of velocity over time. In accordance with another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from a stock supply roll through the forming assembly, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including a velocity sensor for sensing the velocity of stock material through the machine and for communicating the velocity to the controller to calculate the length of cushioning product produced as a function of integral of velocity over time. In accordance with yet another aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly, a severing assembly for severing the continuous strip of cushioning product into a discrete length of cushioning product, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length; and a length measuring device including a sensor locatable at an adjustable distance from the severing assembly which detects the presence or absence of cushioning material adjacent the sensor and which communicates the detection of the cushioning material to the controller. In accordance with a further aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly and through an outlet, a severing assembly for severing the continuous strip of cushioning product into a discrete length of cushioning product, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length; and a length measuring device including a contact positioned at the outlet for engaging the leading edge of the continuous strip of cushioning product and movable with the cushioning product as it progresses from the exit, and a sensor for sensing the position of the contact and communicating the position of the contact to the controller. In accordance with a further aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly and through a machine outlet, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined length, and a length measuring device including scale positioned at the outlet for measuring the weight of the continuous strip of cushioning product and for communicating the weight of the cushioning product to the controller to approximate the length of cushioning product produced as a function of its weight. In accordance with a further aspect of the invention, a cushioning conversion machine includes a forming assembly which converts a stock material into a continuous strip of a cushioning product, a feed assembly for feeding stock material from a stock supply through the forming assembly and through a machine outlet, a weight input allowing an operator to select the weight of the cushioning material to be produced a controller for controlling operation of the feed assembly to produce a cushioning product of the selected weight, and a weight measuring device including scale positioned at the outlet for measuring the weight of the continuous strip of cushioning product and for communicating the weight of the cushioning product to the controller. In accordance with a further aspect of the invention a cushioning conversion machine includes a forming assembly which converts a stock material into a cushioning product, a feed assembly for feeding stock material from supply through the forming assembly, an encoder for generating a series of pulses corresponding generally to the iength of pad formed, a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and an automated Iength calibration mechanism including a Iength measuring sensor for measuring the Iength of a pad after formation. In accordance with another aspect of the invention a method of calibrating a cushioning conversion machine includes the steps of generating and recording a series of pulses inferring the Iength of pad being produced by the cushioning conversion machine, measuring the Iength of the pad actually produced at the output of the machine; and determining at least one correction factor to correlate the number of pulses recorded to the Iength of a pad actually produced. In accordance with another aspect of the invention a method of calibrating a cushioning conversion machine includes the steps of controlling a feed assembly including a feed motor to produce a pad of a predetermined Iength, generating a series of pulses inferring the Iength of pad being produced by the cushioning conversion machine by the movement of the feed assembly and recording the number of such pulses until the feed motor has been instructed to stop, measuring the Iength of the pad actually produced at the output of the machine, recording the number of pulses generated after the feed motor has been instructed to stop, and determining at least one correction factor to correlate the number of pulses recorded to the Iength of a pad actually produced. These and other features of the invention are fully described and particularly pointed out in the claims. The following descriptive annexed drawings set forth in detail one illustrative embodiment, this embodiment being indicative of but one of the various ways in which the principles of the invention may be employed. BRIEF DESCRIPTION OF THE DRAWINGS In the annexed drawings: Figure 1 illustrates a plan view of a cushioning conversion machine schematically illustrating a pad-length measuring device in accordance with the present invention; Figure 2 is a partial elevation view of the cushioning conversion machine illustrated in Figure 1 ; Figure 3 shows a schematic illustration of one embodiment of a pad-length measuring device which measures the Iength of paper unwound from a supply roll by means of a contact roller; Figure 4 illustrates a schematic embodiment of a pad-length measuring device which infers the iength of pad being produced by the change in the radius of the stock supply roll; Figure 5 shows a schematic illustration of an embodiment of a pad-length measuring device which approximates pad Iength by measuring the change in height of supply stock; Figure 6 is a schematic illustration of an embodiment of a pad-length measuring device which measures the iength of pad being produced in accordance with the number of folds of material removed from a stack of stock material; Figure 7 is a schematic illustration of an embodiment of a pad-length measuring device which detects the Iength of material removed from a stock supply by detecting printed indicia on the material; Figure 8 is a schematic representation of pad-length measuring device similar to that shown in Figure 7 which detects the Iength of pad being removed from the stock supply by detecting perforations in the material; Figure 9 illustrates schematically an embodiment of a pad-length measuring device which coordinates in the weight of the supply material to a desired Iength input; Figure 1 0 is a schematic illustration of a pad-weight measuring device similar to that shown in Figure 9 but which correlates the change in weight of the stock supply with a weight input; Figure 1 1 is a schematic representation of a pad-length measuring device which employs an unwinder to unwind a desired Iength of material from a supply roll and a sensor to determine when the unwound material has been converted into a pad; Figure 1 2 is a schematic illustration of a pad-length measuring device which employs an unwinder for unwinding a length of paper from a stock supply roll and a linear sensing array for determining the amount of paper unwound from the stock supply and for determining the Iength of paper converted into a pad; Figure 1 3 is a schematic representation of an embodiment of a pad-length measuring device which allows for the manual unwinding of material from a stock supply and which senses when all of the material manually unwound from the supply has been converted into a pad; Figure 14 is a schematic illustration of a pad-length measuring device which measures the Iength of pad produced as a function of an increase in pressure; Figure 1 5 is a schematic illustration of a pad-length measuring device including a stepper motor which is driven by a number of pulses corresponding to the desired length of pad to be produced; Figure 1 6 is a schematic illustration of an embodiment of a pad-length measuring device which employs a pulse-driven spring wrap clutch to control the amount of material converted into a pad; Figure 1 7 is a schematic illustration of a pad-length measuring device which employs a power sensor to determine when power corresponding to a certain pad Iength has been supplied to the feed motor; Figure 1 8 is a schematic illustration of an embodiment of a pad-length measuring device which employs a contact roller to measure the pad as it is being produced; Figure 1 9 is a schematic illustration of a pad-length measuring device similar to that shown in Figure 1 8 with the contact roller positioned in the machine output; Figure 20 is a schematic illustration of a pad-length measuring device including a sensor which detects perforations in the pad formed during the conversion process to measure the Iength of the pad; Figure 21 is a schematic illustration of a pad-length measuring device similar to that shown in Figure 21 which includes a sensor to detect indicia printed on the pad during the conversion process; Figure 22 is a schematic illustration of a pad-length measuring device which employs a linear array of sensors to sense the Iength of a pad as it is being produced; Figure 23 is a schematic representation of an embodiment of a pad-length measuring device which employs an adjustable optical sensor for measuring the Iength of a pad as it is produced; Figure 24 is a schematic representation of a pad-length measuring device which employs a movable barrier which moves with the pad as it is being produced and a linear sensor which senses the position of the barrier to measure pad Iength; Figure 25 is a schematic illustration of a pad-length measuring device which correlates the weight of the pad as it is being produced to a desired pad Iength; Figure 26 is a schematic illustration of an embodiment of a pad-weight measuring device similar to that shown in Figure 25 which correlates the weight of the pad as it is being produced to a weight input; and Figure 27 is a schematic illustration of an embodiment of a pad-length measuring device which measures the Iength of pad produced as a function of velocity. DETAILED DESCRIPTION With reference to the drawings and initially to Figures 1 and 2, there is shown a cushioning conversion machine 1 0 including a conversion assembly 1 2 for converting stock material to a packaging pad, a pad-length measuring device 1 4 (illustrated schematically in Figure 1 ) for measuring the Iength of pad produced, a paper severing assembly 1 6 for severing, cutting, tearing or otherwise disconnecting the pad from the stock material in the conversion assembly and, preferably, a controller 1 8 (illustrated schematically) for controlling operation of the machine. The conversion assembly 1 2 preferably includes a forming assembly 22 and a feed assembly 20 which includes a gear assembly 24 powered by a feed motor 26. Operation of the severing assembly 1 6 is powered by a cut motor 30 selectively engaged with the severing assembly by a clutch 31 . The controller 1 8 controls operation of the feed motor 26, cut motor 30, the clutch 31 , etc., in response to various data and control inputs, such as those from the pad-length measuring device 14. The feed motor 26 powers the gear assembly 24 through a drive arrangement 34 which may include a number of elements such as the sprockets 38, chain 40 and shaft 42 for transferring rotational power to the gear assembly. The gear assembly 24 includes two opposed gears 44 and 46 (see Figure 2) of which one gear, such as gear 44, is a drive gear preferably driven by the drive arrangement 34 while the other gear, in this case gear 46, is in the form of an idler gear. During the conversion process, sheet-like stock material is pulled from a roll of material held by a stock supply assembly 48 and transferred to the conversion assembly 1 2. (The sheet-like stock material may consist of three superimposed webs of biodegradable, recyclable and reusable thirty-pound Kraft paper rolled onto a hollow cylindrical tube as shown in Figure 3, or some other number of plies of sheet-like material, or a fan-folded stack of material as shown in Figure 5.) The sheet-like stock material (herein, paper) is converted into continuous strip of padding by the conversion assembly 1 2 from where it emerges to be disconnected from the material still in the conversion assembly by the severing assembly 1 6 to form a pad of the desired Iength at the transitional zone 50. More specifically, as paper is pulled through the forming assembly 22 by the gear assembly 24, the forming assembly causes the lateral edges of the stock material to roll inwardly to form a continuous strip having two lateral pillow-like portions and a central band therebetween. The gear assembly 24 performs a "pulling" function by drawing the continuous strip through the nip of two cooperating and opposed gears of the gear assembly 24 thereby drawing stock material through the forming assembly 22 for a duration determined by the Iength of time that the controller 1 8 instructs the feed motor 26 to rotates the driven gear 44. As the gear assembly 24 pulls the strip through the forming assembly 22, the gears 44, 46 additionally perform a "coining" or "connecting" function as the opposed gears coin the central band of the continuous strip as it passes therethrough to form a coined strip. As the coined strip travels downstream from the gear assembly 24, the leading edge of the strip passes through the severing assembly 1 6 to the transitional zone 50. The controller 1 8, which monitors the Iength of pad produced as determined by the pad-length measuring device 1 4, stops the feed motor 26 once an appropriate Iength of pad has been formed and instructs the severing assembly 1 6 to sever the strip to result in a pad of the desired Iength. The Iength of pad to be produced may be communicated to the controller 1 8 as an input (such as shown schematically by lines 52) by the operator through B keypad, a thumb wheel or some other device. Alternatively, the Iength may be preset or may be a function of adjustment of sensors, as described below . The pad may be deposited onto a slide or chute or may be mechanically transferred to another location for use by an operator. One embodiment of a pad-length measuring device 1 4 is illustrated in Figure 3. The pad-length measuring device 1 4a includes a roller sensor 60 in contact with the paper 62 fed from the roll of paper 64. With the feed motor 26 turning, as paper 62 is pulled from the roll 64 by engagement with the turning gears 44, 46 of the gear assembly 24, the paper causes a friction wheel 66 of the roll sensor 60 in contact with the paper to rotate thus transferring the linear movement of the paper into rotational movement by the friction wheel as it roils along the moving paper. The roll sensor 60 translates the rotation of the wheel 66 into pulses which are sent to the controller 1 8 along signal line 68. The controller 1 8 counts the pulses and when the accumulated number of pulses corresponds to a desired Iength of pad, the controller 1 8 deactivates the feed motor 26 via control line 70 so that no additional paper is fed from the roll. The controller then instructs the cutter mechanism 32 (which represents the severing assembly 1 6, the cut motor 30 and the clutch 31 ) via control line 72 to cut the pad at the desired Iength. The pad Iength is determined by the state of a Iength input device 74 which may include a key pad through which the operator can set the pad lengths to be formed as well as through a thumb wheel or similar device. The selected pad Iength is communicated to the controller 1 8 over the signal line 76. In some instances, such as when the pad Iength is input through a keypad, the desired Iength of the pad is stored in a memory device accessible by the controller 1 8. It is noted that while the pad-length measuring device 1 4a shown in Figure 3, as well as several other embodiments of the pad-length measuring device 1 4 described below, do not measure the pad directly, but rather measure the paper before it is converted, the ratio of the Iength of paper to the pad is relatively constant for most conversion operations and thus can be compensated for within a few percent by the controller 1 8. Referring to Figure 4, there is shown an embodiment of the Iength measuring device 1 4b which translates the radius of the stock supply roll 64 into an indication of the Iength of paper removed from the roll since the last cut. The paper-length measuring device 1 46 includes a position-sensing device 80 for directly or remotely sensing the position of the periphery 82 of the paper supply roll 64. The position-sensing device 80 periodically senses and reports an indication of the radius of the paper supply roll 64 to the controller 1 8 over the data line 84. The controller 1 8 determines the linear Iength of paper that has been unwound from the paper supply roll since the last cut as a function of the last reported paper supply roll radius and the stored paper roll radius at the time of the last cut. When the linear Iength of paper unwound since the last cut equals or exceeds the desired Iength for the pad as received from the iength input device 74, the controller 1 8 deactivates the feed motor 26 thus stopping the gear assembly from pulling additional paper from the paper roll and instructs the cutter mechanism 32 to cut the pad by engaging the cut motor 30 with the severing assembly 1 6 to sever the pad at the desired Iength. The controller 1 8 then stores the last read paper supply roll radius for use in computing the Iength of the next pad . The position-sensing device 80 preferably includes a positional probe 86, such as that shown in Figure 4, in the form of contact roller which is biased against and rolls with the periphery of the paper supply roll 64 as paper is unwound, and a linear sensor 88 for determining the distance between the positional probe 86 and a fixed reference 90, such as the machine frame. The linear sensor 88 provides the radius information to the controller 1 8 in the form of a data signal indicating the radius of the supply roll 64 over line 84. With reference to Figure 5, there is shown an embodiment for a length-measuring device 1 4c which senses the Iength of pad formed by keeping track of the height of the folded paper supply stack 92. Such an embodiment of the Iength measuring device is particularly applicable when the supply paper is in the form of fan-folded paper which is stacked in a continuous zig-zag or accordion arrangement. A cushioning conversion machine operable to convert such stock material to cushioning material is disclosed in U.S. Patent No. 5,387, 1 73 which is incorporated herein by this reference. The Iength measuring device 1 4c may directly or remotely sense the height of the paper supply stack 92 relative to a fixed location 94, such as a fixed point on the machine frame, and provides the indication of height or change in height to the controller 1 8 via line 96. In the instance where absolute height is supplied to the controller 1 8, the controller subtracts the height of the stack 92 when the last cut occurred and correlates this change in height information with information which translates the height information to linear Iength of the pad produced. When the pad-length measuring device 14d provides the relative paper supply height to the controller 1 8, the information may be provided in the form of a pulse which is generated and transmitted to the controller 1 8 each time a certain increment of paper has been removed from the paper supply stack 92. Upon receipt of the height information from the pad-length measuring device 1 4d, the controller 1 8 will determine the Iength of pad which has been produced based on the decrease in the height of the paper supply stack 92 since the last pad was produced and compare the amount produced to that desired. If the amount produced is greater than or equal to the amount desired, the controller 1 8 will cease pad production and instruct the cutting mechanism 32 to perform a cut, as described more fully above. The pad-length measuring device 1 4d may include a contact arm 98 which contacts the top of the paper supply stack 92 and a positional sensor 1 00 which senses the position of the contact arm and provides an indication of the position of the arm to the controller 1 8 via the line 96, or some other means of sensing the stack height. The positional information generated by the positional sensor 1 00, as noted above, may be in the form of a signal indicating the height of the paper supply stack 92 as an analog or digital value or the information may be in the form of a pulse generated when each time the height has decreased by a certain amount. In Figure 6 there is shown a pad-length measuring device 1 4e which employs a trip switch which senses each time that a fold of paper on one edge of the paper stack 92 has been removed from the stack. The pad-length measuring device 14e generates a pulse each time that it has detected that a fold of paper has been removed from the stack and transmits the pulse to the controller 1 8 via the line 1 02. By counting the pulses, the controller 1 8 can determine the Iength of paper pulled from the stack 92 for conversion to a pad then, once the appropriate Iength of paper has been removed as determined by the Iength input device 74, the controller will instruct the feed motor 26 and cutter mechanism 32 to stop the production of additional padding and to sever the pad at the appropriate Iength. The pad-length measuring device 1 4e may include a trip switch 1 04 having an extending contact arm 106 which contacts the top of the paper supply stack 92 and provides an indication, such as through its movement, to the trip sensor 1 04 when a fold of paper beneath the contact arm has been removed from the stack. Preferably, the trip switch sensor 1 04 is mounted relative to the machine frame 94 in such a way that its height is adjustable so that the contact arm 1 06 will maintain contact with the paper supply stack 92 as paper is removed. A pad-length measuring device 1 4f which employs a sensor responsive to indicia on the stock material to determine the Iength of paper being pulled from a roll of stock material 64 is illustrated in Figure 7. The pad-length measuring device 1 4f includes a sensor 1 08 which detects the presence of certain indicia encoded on the paper 1 1 0 as it passes by the sensor 1 08. Length information may be encoded on the paper 1 1 0 in the form of visible gradations 1 1 2, as shown in Figure 7a, which are detected by the sensor 1 08 as the gradations pass by the sensor. Alternatively, the sensor 1 08 may operate on invisible or ultraviolet wavelengths of light to detect suitable indicia printed on the paper 1 10. As the sensor 1 08 detects a gradation, such as 1 1 2, on the paper 1 1 0 it generates a pulse which is communicated to the controller 1 8 over the line 1 1 2. By counting the pulses, the controller 1 8 can determine the Iength of paper having been pulled from the paper supply roll 64, and thus the Iength of the pad having been formed, since the last cutting operation. When the Iength of pad produced since the last cutting operation is equal to or greater than the Iength input provided by the Iength input device 74, the controller will then instruct the feed motor 26 and cutter mechanism 32 appropriately to sever the paper to produce a pad of the desired Iength. Turning to Figures 8 and 8a there is shown an embodiment of a pad-length measuring device 1 4g similar to that illustrated in Figure 7, but which detects perforations 1 1 4 in paper stock 1 1 6 as the paper passes by a sensor 1 1 8. The sensor 1 1 8 detects the presence of a perforation 1 1 4 by sensing the difference in light reflection to the sensor when the light ray generated by the sensor is incident through a perforation as opposed to incident on the paper. A light reflecting or absorbing media 1 20 is positioned below the perforations 1 1 4 in the paper stock 1 1 6 to enhance the difference in light reflected to the sensor 1 1 8 when a perforation 1 1 4 is in the path of incident light generated by the sensor. The media 1 20 may be reflective thus enhancing the amount of light reflected to the sensor 1 1 8 when a perforation passes by the sensor, in which case the sensor will detect these increases in the amount of light reflected as corresponding to the presence of a perforation, or the media 1 20 may be light absorbing in which case the sensor 1 1 8 will detect the decrease in light reflected to the sensor as indicating the presence of a perforation. The sensor 1 1 8 generates a pulse each time a perforation 1 14 is detected in the paper stock 1 1 6 and transmits the pulse to the controller 1 8 via line 1 20. The controller 1 8 counts the received pulses since the last time that paper was severed to form a pad in order to determine the Iength of a pad currently being produced. The controller 1 8 then instructs the feed motor 26 and cutter mechanism 32 appropriately to produce a pad of the desired Iength. Referring to Figure 9 there is shown a pad-length measuring device 1 4h which weighs the stack of fan-fold paper 92 available for conversion into a pad. Based on the difference between the weight at the completion of the formation of the last pad and the current weight as communicated to the controller 1 8 over line 1 22 via the pad-length measuring device 1 4h, the controller 1 8 can determine the weight, and thus the Iength of paper removed from the paper supply since the last pad was formed. When the Iength of pad is equal to or exceeds the desired Iength of pad as communicated to the controller 1 8 by the Iength input device 74, the controller 1 8 will then instruct the feed motor 26 and cutter mechanism 32 appropriately to discontinue the pad formation and sever the pad. The pad-length measurement device 1 4h preferably includes a scale 1 24 having sufficient resolution to detect the removal of relatively small lengths of paper from the paper supply stack 92 allowing the accurate measurement of padding as it is being formed. The paper weight as sensed by the indicator shown schematically at 1 26 is provided to the controller over the line 1 22. The weight of the paper supply stack 92 may be provided to the controller as a real weight value or the change in weight may be provided as a pulse in which the indicator 1 26 sends a pulse to the controller 1 8 each time a certain amount of weight is removed from the paper supply stack 92. The controller 1 8 then functions as described above based on the Iength input to control the feed motor 26 and cutter mechanism 32 to provide a discrete pad of the appropriate iength. A pad-weight measuring device 1 4i similar to that described above with respect to Figure 9 but which receives the desired weight of the pad to be produced as an input as opposed to the Iength input is illustrated in Figure 1 0. The pad-length measuring device 1 4i includes the scale 1 24 and indicator 1 26 as described above for providing weight information to the controller 1 8 via line 1 22. It is noted that while Figure 9 illustrates a supply stack of fan-fold stock material 92 and Figure 1 0 illustrates a paper supply roll 64, either paper supply could be used interchangeably with the systems described relative to Figures 9 and 1 0. The controller 1 8, in addition to receiving the information regarding the weight of the paper supply roll 64 from the pad-length measuring device 1 4i, also receives a weight input 1 28 over the line 1 30. The weight input 1 28 may be an operator input provided through a keypad or some other means. In this embodiment, the controller 1 8 determines when the weight of paper pulled from the paper supply roll 64 is equal to or greater than the desired weight for the pad as supplied by the weight input 1 28. The controller 1 8 then instructs the feed motor 26 and cutter mechanism 32 to cut the pad to the appropriate Iength having the desired weight. Such an embodiment is particularly suitable for instances in which it is desired that the package which is to be filled with the padding is to have a specified weight, such as when it is desired to keep the weight below a certain value so as to reduce postal costs, for example. In Figure 1 1 there is shown a pad-length measuring device 1 4j which includes an unwinder 1 32 for unwinding paper from the paper supply roll 64 and a sensor 1 34 for controlling the operation of the feed motor 26 in accordance with whether paper 1 36 which has been unwound from the supply roll is available for conversion into a pad or whether the material which has been unwound has already been converted into a pad. The controller 1 8 instructs the unwinder 1 32, which may include one or more rollers 1 38 powered by a motor 1 40, to unwind paper from the paper supply roll 64 for a time period sufficient to unwind the desired Iength of paper to be converted into a pad as determined by the input from the Iength input device 74. The sensor 1 34 may include a probe, such as a contact roller 1 42, and a position sensor 1 44 for sensing the position of the contact roller. As paper 1 36 is unwound from the paper supply roll 64 by the unwinder 1 32, the paper will festoon in the area of the contact roller 1 42 such that the contact roller extends away from the sensor 1 44. In such a condition the sensor 1 44 will instruct the feed motor 26 via line 1 46 to operate to feed paper through the forming assembly 22 to convert the festooned paper into a pad. Once the paper 1 36 unwound from the supply roll 64 has been pulled through the conversion assembly by the feed motor 26, the paper will become relatively taut in the area of the contact roller 1 42 causing the contact roller to move toward the sensor 1 44. Once sensor 144 has detected that all of the unwound paper has been converted to padding, as determined by the position of the contact roller 1 42, the sensor 1 44 will instruct the feed motor 26 via line 1 46 to cease feeding paper through the forming assembly 22. Once an adequate time has lapsed for the paper 1 36 unwound from the supply roll 64 to be converted into a pad, the controller 1 8 will instruct the cutter mechanism 32 to sever the converted strip of paper into a pad of the desired Iength. Alternatively, the sensor 1 44 may provide a direct input to the controller 1 8 to inform the controller when the paper 1 36 festooned from the stock supply roll 64 has been fully converted into a pad as determined by the position of the contact roller 142. In Figure 1 2 there is shown a pad-length measuring device 1 4k which includes an unwinder 1 54 for unwinding paper 1 56 from a roll of stock paper 64 and a linear array of sensors 1 58 for determining the Iength of unwound paper 1 56 having been fed to the forming assembly 22 of the cushioning conversion machine by the feed motor 26. The unwinder 1 54 is controlled by the controller 1 8 over the line 1 60 and unwinds paper 1 56 from the stock supply roll 64 until the controller determines, based on an input over line 1 62 from the sensor array 1 58 that the desired amount of paper has been unwound from the supply roll . The sensor array 1 58 preferably includes a number of sensors, for example, sensors 1 58a through 1 58h illustrated in Figure 1 2, which are sufficient to detect various discrete Iength of paper 1 56 unwound from the stock supply roll 64 and falling into a festoon before the sensor array. Preferably, the number of sensors 1 58a through 1 58h and the spacing of the sensors is adequate to ensure that the desired Iength of pad, over various increments, can be produced. In operation, the controller 1 8 will instruct the unwinder 1 54 via line 1 60 to unwind paper 1 56 from the stock supply roll 64. As the paper is unwound from the stock supply roll 64 it sags into a festoon generally indicated at 64 progressing from the first sensor 1 58a across the various sensors 1 58b through 1 58h as more paper is unwound . If, for example, a five foot pad were to be produced, and each of the sensors 1 58a through 1 58h were spaced one-half foot apart, as paper was unwound and was detected by each sensor 1 58, the sensor would report the detection of the paper to the controller 1 8 over line 1 62. When the festoon of paper 1 56 extended 2 1 /2 feet from the first sensor 1 58a, and thus was detected by sensor 1 58f, sensor 1 58f would report the sensing of the paper 1 56 to the controller 1 8 over line 1 62 which would then stop the unwinder 1 54 and instruct the feed motor 26 to begin feeding the paper through the forming assembly 22 to create the pad. As paper was pulled from the festoon 1 64 by the feed motor 26, the size of the festoon would decrease and the individual sensors 1 58a through 1 58f of the sensor array 1 58 would sequentially stop detecting the presence of paper. Once the sensor 1 58a no longer detected the presence of paper 1 64, the controller 1 8 would stop the feed motor 26 and instruct the cutter mechanism 32 to engage the severing assembly 1 6 with the cut motor 30 to cut the converted paper into a pad of the desired Iength. A further embodiment of a pad-length measuring device 1 4j which allows an operator to manually determine the Iength of paper to be converted into a pad by pulling the desired Iength of paper from the paper supply roll 64 is shown in Figure 1 3. The pad-length measuring device 1 4j includes a scale or reticle 1 66 which the operator can use to measure the Iength of paper pulled from the paper supply roll 64 and a sensor switch 1 68 which controls the feed motor 26 and cutter mechanism 32 in accordance with whether the paper in an area 1 70 in a path of an alignment roll 1 72 through the conversion assemblies is slack, indicating that all of the paper which the operator unwound from the paper supply roll 64 had not yet been converted into padding, or whether the paper 1 70 is taut indicating that all of the paper pulled from the supply roll had been converted into a pad. The sensor switch 1 68 preferably includes a contact roller 1 74 for rolling contact with the paper in the area 1 70 in communication with a positional sensor 1 76 which acts as a switch according to the position of the contact roller 1 74. When an operator desires for a particular Iength of paper to be converted into a pad, the operator pulls the desired Iength of paper, indicated by the dash line 1 74, from the paper supply roll 64 using the scale 1 66 as a guide to determine the appropriate Iength. Once the operator lets go of the paper 1 78, the paper at the position 1 70 will become slack thus allowing the contact roller 1 74 to move to a lower position and the sensor 1 76 to instruct the feed motor 26 to pull paper through the forming assembly 22 to produce a pad. The process of pulling paper through the forming assembly 22 and forming a pad will continue until the paper 1 78 pulled from the paper supply roll 64 has been converted into a pad whereupon the paper in the area 1 70 will become taut thus moving the contact roller 1 74 to a second position whereupon the sensor switch 1 68 will disengage the feed motor 26 and engage the cutter mechanism 32 over line 1 79 to cut the converted paper into a pad of the appropriate Iength. In Figure 1 4 there is shown an embodiment of a pad-length measuring device 14k which includes an air pump 1 80 which is operated along with the drive gear 44 by the shaft 42, a reservoir 1 82 for accumulating pressure and a pressure sensor 1 84 for sensing the pressure in the reservoir. In operation, the controller 1 8 instructs the feed motor 26 over line 70 to pull paper through the forming assembly 22 by driving the drive gear 44 via the sprockets 38, the chain 40 and the shaft 42. As the feed motor 26 turns the drive gear 44 to convert the paper into a pad, the air pump 1 80 generates increased air pressure over the line 1 86 to the reservoir 1 82. The pressure buildup in the reservoir 1 82 is sensed by the pressure sensor 1 84 which, through an offset switch 1 88, instructs the controller 1 8 when a pressure exceeding the offset of the offset switch has been achieved in the reservoir. The offset switch 1 88 is offset or biased by the Iength input so that the pressure which actuates the switch to indicate to the controller 1 8 that the appropriate amount of padding has been produced is a function of the Iength input device 74. Once the controller 1 8 has been informed that a pressure has been built up corresponding to the desired pad Iength, the controller 1 8 will instruct the cutter mechanism 32 over line 72 to cause the cutter mechanism 32 to sever the converted paper into a pad. At the same time, the pressure in the reservoir 1 82 is relieved through the pressure valve 1 90 controlled over the line 1 92. In some embodiments, the pressure accumulated in the reservoir 1 82 could be used to power or assist in powering the severing assembly 1 6. Although the embodiment described above utilizes air pressure to measure the Iength of pad being produced, a similar pressure sensing device using hydraulic fluid could be used. In such a device, the level of hydraulic fluid accumulated in a reservoir could be sensed and that level could be used to instruct the controller 1 8, such as through the offset switch 1 88, when the appropriate level of fluid corresponding to a desired pad Iength has been reached. Figure 1 5 illustrates an embodiment of a pad-length measuring device 1 41 which employs a stepper motor 26' operated by pulses produced by the controller 1 8. Based on the desired Iength of pad as input by the Iength input device 74, the controller 1 8 will generate an equivalent number of pulses, illustrated at 1 96, over the line 70 to cause the stepper motor 26' to rotate through the desired number of steps, thus causing the drive gear 44 to turn a known distance to pull an equivalent distance of paper through the forming assembly 22. Once the controller 1 8 has generated the required number of pulses 1 96 equivalent to the desired Iength of pad to be produced, the controller 1 8 will instruct the cutter mechanism 32 to engage the severing assembly 1 6 with the cut motor 30 to sever the converted paper into a pad of the desired Iength. With reference to Figure 1 6 there is shown an embodiment of a pad-length measuring device 1 4m which employs a multiposition, wrapped spring clutch 200 which engages the drive gear 44 with the feed motor 26 as appropriate to form a pad of the desired Iength. In operation, the feed motor 26 is continuously operating rotating the sprockets 38 through chain 40. The upper sprocket 38 is selectively engaged with the shaft 42 which powers the drive gear 44 to pull stock material through the forming assembly 22 as determined by the state of the wrapped spring clutch 200. The wrapped spring clutch 200 is controlled by the controller 1 8 via line 202. The spring clutch 202 includes a number of incremental stops permitting the clutch to engage the shaft 42 with the sprocket 38 for a given degree of rotation. Each time the spring clutch 200 is provided with a pulse from the controller 1 8 it will advance to the next stop thereby engaging the shaft 42 with the sprocket 38 for that degree of rotational advance. The number of rotations of the drive gear 44, and thus the Iength of stock material which is converted into a pad, can thus be controlled by providing a set number of pulses to the spring clutch corresponding to the desired iength of pad to be produced. The controller 1 8 is provided, as discussed above, with a Iength input from the Iength input device 74 and can correlate the desired Iength input with the correct number of pulses to send to the spring clutch 200. Once the controller 1 8 has caused the spring clutch 200 to engage the drive gear 44 with the feed motor 26 to create a pad of the appropriate Iength, the controller 1 8 then instructs the cutter mechanism 32 to sever the converted material into a pad. Referring to Figure 1 7 there is shown a pad-length measuring device 1 4n which is operable to approximate the Iength of pad produced by the machine by converting the desired Iength of pad to be produced into the amount of power needed to supply the feed motor 26 for the feed motor to operates for a duration sufficient to feed the appropriate Iength of material through the forming assembly 22. The pad-length measuring device 1 4n includes a power sensor 206 in communication with the controller 1 8 via lines 208 and 21 0 for sensing the power supply to the feed motor 26 and indicating the level of power provided to the feed motor 26 to the controller 1 8. In operation, the controller 1 8 will translate the desired Iength of pad to be produced as input by the Iength input device 74 into the amount of power necessary to supply to the feed motor to produce a pad of that iength . The controller 1 8 will then cause power to be supplied to the feed motor 26 via line 21 0 to begin the formation of a pad. As power is supplied to the feed motor 26 over the line 21 0, the power sensor 206 senses the power supplied and feeds an indication of the power supplied back to the controller 1 8 over the line 208. The controller 1 8 then monitors the line 208 and causes the power to be terminated to the feed motor 26 once an adequate amount of power has been supplied to the feed motor 26, as sensed by the power sensor 206, to produce a pad of the desired Iength. The feed motor supplies rotational power to the drive gear 44 through the sprockets 38, the chain 40 and the shaft 42, without the need of the clutch assembly 200 discussed immediately above. Figure 1 8 illustrates a cushioning conversion machine 1 0 employing a pad-length measuring device 14p which measures the Iength of a pad after it has been formed and before it has been severed. The Iength measuring 1 4p includes a rotating mechanism 21 2 disposed between the gear assembly 24 and the severing assembly 1 6 which frictionally engages and rolls with the pad as it progresses from the gear assembly to the severing assembly. The rotating mechanism 21 2 may include a contact roller, a gear, a sprocket or some other means for converting the linear movement of the pad into rotational movement. An encoder 21 4 translates the rotational movement of the rotating mechanism 21 2 into a signal, such as a pulse signal, which is provided to the controller 1 8 over the line 21 6. In operation, the controller 1 8 will instruct the feed motor 26 to power the drive gear 44 of the gear assembly 24 thus pulling stock material through the forming assembly 22 and through the nip portion 21 5 of the gears 44 and 46 and causing the pad material to progress across the rotating mechanism 21 2, through the severing assembly 1 6 and into the transitional zone 50. As the pad is formed and moves across the rotating mechanism 21 2, the encoder 214 supplies an indication of the Iength of pad produced to the controller 1 8 which monitors the encoded indication of pad produced and stops the feed motor 26 when the desired Iength of pad has been produced . The cutter mechanism 32 is then caused to engage the severing assembly 1 6 with the cut motor 30 to sever the cushioning product into a pad of the desired Iength. In Figure 1 9 there is shown a pad-length measuring device 1 4q very similar to the pad-length measuring device 1 4p shown in Figure 1 8. The pad-length measuring device 14q includes a rotating mechanism 21 2' and an encoder 214' which translates the rotational movement of the rotating mechanism into a signal which is sent to the controller 1 8 over the line 21 6' . The pad-length measuring device 1 4q differs from the pad-length measuring device 14p in that the rotational mechanism 21 2' is disposed in the transitional zone 50. The transitional zone 50 may include an output chute, a constraining assembly or a conveyor, for example. In operation, the pad-length measuring device 1 4q will function as discussed above for the pad-length measuring device 14p. Figures 20 and 21 show alternate embodiments of the pad-length measuring devices 1 4p and 1 4q in which an optical sensor 220 replaces the rotating mechanism 21 2 and encoder 21 4. The optical sensor 21 8 senses indicia printed on, encoded on, impressed in, or punched through the pad P as the pad is formed or shortly thereafter. In the pad-length measuring device 1 4r illustrated in Figure 20, one of the gears 44, 46, such as the top gear 46, preferably includes an extension 21 7 on one of the gear teeth for causing a perforation 220, shown in Figure 20A, in the coined region or central band of the pad P. As the pad P progresses past the optical sensor 21 8, which preferably includes an optical transmitter and optical receiver, light transmitted from the sensor passes through a perforation 220 and is reflected to the sensor by a reflector 222. The detection of a perforation, by the increased light reflection, is signaled to the controller 1 8 over the line 224 which counts the detected perforations to determine the pad Iength . Alternatively, the reflecting media 222 can be a light-absorbing media in which case the optical sensor 21 8 would detect instances of decreased light reflection to indicate the presence of a perforation. The controller 1 8 counts the detections of the perforations and correlates the count with the desired Iength of the pad to be produced and controls the feed motor 26 and cutter mechanism 32 appropriately, as discussed above, to produce a desired pad. The pad-length measuring device 14s, illustrated in Figure 21 , detects an indicia 226, as shown in Figure 21 a, printed on the pad P, during or shortly after the pad passes through the gears 24. As an example, one or more of the gear teeth of a gear 44, 46 may include a projection 228 which contacts an inking roller (not shown) as the projection rotates and which prints a line indicia 226 on the pad P as it contacts the pad P as the projection is pulled through the nip 21 8 of the gears. Alternatively, the indicia 226 could be printed on the paper prior to conversion into the pad, such as prior to it being rolled onto the stock supply roll or folded into a fan- fold stack. The optical sensor 21 8' detects the variances in reflected light caused by the indicia 226 and provides a pulse or similar signal to the controller 1 8 over the line 224 to indicate the detection of the indicia. Alternatively, the optical sensor 21 8' could be replaced with an ultrasonic sensor or some other type of sensor, which senses depressions, impressions, ridges and/or valleys in the pad P to measure the Iength of pad as it progresses past the sensor. In Figure 22 there is shown a pad-length measuring device 1 4t which includes a linear array of sensors 234 disposed along an output extension 240 to determine the Iength of the pad P. Each of the sensors 236a through 236e is preferably an optical sensor having a corresponding optical media 238a through 238d associated therewith disposed on the other side of the pad P and output extension 240 for either reflecting or absorbing light transmitted by the optical sensors 236a through 236e. The optical sensors 236a through 236d of the linear array 234 are preferably spaced so as to detect certain likely increments of pad lengths to be selected. Each of the optical sensors 236a through 236e is disposed at the selected distance relative to a opening or light transmissive region 241 in the output extension 240 allowing for an uninterrupted optical path between an optical sensor and its associated optical media 238 in the absence of a pad P. When the leading edge of the pad P progresses through the output 50 and across the extension 240, it will first interrupt the optical path between the optical sensor 236a and associated optical media 238a and the sensor 236a will communicate the detection of the pad to the controller 1 8 over the line 242a. As the pad continues to progress across the output extension 240, towards the right in Figure 22, it will interrupt the optical path of successive optical sensors 236b through 236e and associated optical media 238b through 238e and each of those sensors as their optical path is interrupted will report the detection of the pad P to the controller 1 8 via lines 242b through 242e. Based on which way the optical sensors 236a through 236e of the linear sensing array 234 which have reported the presence of the pad P interrupting their respective optical paths, the controller 1 8 can determine the Iength of the pad as it is produced. Once the pad P produced is equal to or exceeds the desired Iength as communicated by the Iength input device 74 the controller 1 8 will stop the feed motor 26 and instruct the cutter mechanism 32 to cut the pad to the desired Iength. In Figure 23 is shown a pad-length measuring device 1 4u which employs a linearly adjustable sensing device for determining when a pad has reached a certain adjustable Iength. The pad-length measuring device 1 4u includes an optical sensor 242 which is linearly adjustable along a support 244 oriented relative to the output extension 246 such that the optical sensor 242 has a view of the pad P when in position in the output extension . The output extension 246 is preferably provided with a scale or reticle 248 which allows the operator to determine the Iength, such as in inches, at which to position the optical sensor 242. In operation, the optical sensor 242 is adjusted to the position on the support 242 desired for the appropriate Iength pad. The controller 1 8 will then instruct the feed motor 26 to begin feeding stock material through the forming assembly 22 to produce the pad P. As the pad P emerges from the machine output 50 and progresses along the output extension 246 it will eventually enter the optical path of the optical sensor 242. The optical sensor 242 may detect the presence of the pad P by increased reflection from the pad as opposed to when the pad is absent or the optical sensor may be provided with a corresponding reflective media (not shown) which provides a significant amount of reflective light in the absence of a pad and thus allows the sensor to easily detect the presence of a pad by the reduction in the amount of light reflected by the pad P to the optical sensor. When the optical sensor 242 detects a pad P, it sends a signal or pulse along the line 250 to the controller 1 8. Upon receipt of the signal from the optical sensor 242, the controller 1 8 will instruct the feed motor 26 to cease producing additional pad and the controller 1 8 will instruct the cutter mechanism 32 to cause the pad P to be severed at the appropriate Iength. A further embodiment of a pad-length measuring device 1 4v is illustrated in Figure 24. The pad-length measuring device 14v includes a moving barrier 254 coupled to a linear sensor 256 for sensing the position of the movable barrier. The movable barrier 254 and linear array 256 may be embodied in such a way that the movable barrier will contact the pad P very near the output 50 of the machine and move with the pad with the linear sensor recording the position of the movable barrier and reporting that position to the controller 1 8 along the line 258. In such a case, the controller 1 8 would monitor the position of the movable barrier 254 as provided by the linear sensor 256 over line 258 and once the position of the movable barrier was consistent with the Iength input as provided to the controller 1 8 by the Iength input device 74, the controller 1 8 would cause the feed motor 26 to stop producing additional pad and would instruct the cutter mechanism 32 to sever the pad. Alternatively, the movable barrier 254 could be adjustable at a position relative to the output extension 246 and could operate such that once the pad reached the preset point of the movable barrier 254 and moved the barrier beyond this position, as detected by the linear sensor 256, the movable barrier and linear array would act as a trip switch and send a pulse to the controller 1 8 along the line 258 once the pad had contacted and moved the movable barrier. In this case the Iength input device 74 would not be necessary and the controller 1 8 would need only to wait for the detection of a pulse from the linear sensor 256 in order to cease the feed motor 26 operation and instigate a severing operation of the pad. In Figures 25 and 26 there is shown an embodiment of a pad weight or length-measuring device in which the weight of the pad P on an output scale 260 is sensed and reported to the controller 1 8 along the line 262. In the embodiment of the pad-length measuring device 1 4w illustrated in Figure 25, the controller 1 8 receives a Iength input from the Iength input device 74 and translates the desired Iength input into the weight of the pad P for such a Iength. Consequently, as the pad P emerges from the machine output 50, the scale 260 will report the weight over the line 262 to the controller 1 8 which will compare the weight to the weight corresponding to the desired Iength input. Once the desired weight has been reached or exceeded, the controller 1 8 will then cause the feed motor 26 to stop and the cutter mechanism 32 to cause the pad P to be severed. In the embodiment of the weight-input measuring device 1 4x shown in Figure 26, the controller 1 8 is provided with a weight input from the weight input device 1 28. As the pad P progresses from the machine output 50, the controller 1 8 will monitor the weight of the pad as provided by the scale 260 via line 262 and compare the sensed weight to the input weight. Once the sensed weight equals or exceeds the weight input, the controller 1 8 will cause the feed motor 26 to stop the production of additional pads and activate the cutter mechanism 32 to sever the pad P at the appropriate weight. Referring to Figure 27, there is shown an embodiment of a pad-length measuring system 1 4y which employs a velocity sensor 270 to sense the velocity of one of the rotating components of the cushioning conversion assembly 1 2, or the velocity of the paper through the machine, to determine the Iength of a pad being formed. The velocity sensor 270 may be an optical sensor, a magnetic sensor, etc., which through some means determines the velocity of the paper or of a cushioning conversion component and provides a digital or analog indication of the velocity over time to the controller 1 8 via line 272. The controller 1 8 can convert the velocity data to Iength by calculating the integral of the velocity as a function of the pad formation duration and multiplying the result by a constant which accounts for gear ratios, etc., depending on where the velocity was sensed. In operation, the controller 1 8 determines the iength of pad to be produced by referring to the Iength input 74 and instructs the feed motor 26 to begin feeding paper through the forming assembly 22. As the sensed cushioning conversion component, such as the drive gear 44, begins to rotate, the velocity sensor 270 will begin transferring velocity data to the controller 1 8 over the line 272. The controller 1 8 will calculate the Iength of pad produced from the velocity data and compare the converted Iength with the desired Iength. Once the calculated Iength of paper converted into a pad equals the desired pad Iength, the controller 1 8 will instruct the feed motor 26 and cutter mechanism 32 appropriately to stop the pad production and sever the converted paper into a pad. A further embodiment of the Iength measuring device 1 4 is described in co-owned U.S. Patent No. 5,571 ,067, which is incorporated in its entirety by this reference. In this embodiment, Iength of the formed pad is determined by sensing the rotation of the gears 44 and 46 using an electro-optical device. There are many factors which effect the actual Iength of a pad produced to varying degrees. One factor is that the feed motor 26 after being instructed to stop by the controller 1 6 may coast or overrun before coming to a complete stop. Other factors include the type and condition of the stock material and the moisture content of the stock material, for example. To improve the accuracy of creating a pad of a desired Iength it is desirable in some instances to calibrate the cushioning conversion machine to accommodate or correct for changes which effect pad Iength. The calibration may be performed manually which typically requires interaction between the operator and the cushioning conversion machine or more preferably in an automated fashion. Such calibration may be performed at prescribed time or usage intervals, as requested by an operator, such as by depressing a calibration button associated with the controller 1 8, or each time a pad is produced. Practice has found that for a cushioning conversion machine having at least one sensor which directly or indirectly senses the Iength of a pad as it is produced and generates a series of corresponding pulses, the Iength of the pad can be characterized by the equation: Pad Length = K 1 * (Number of Encoder Pulses) + K 2 where: K, is a constant that relates to the Iength of pad produced per encoder pulse; and K 2 is a constant that relates to Iength of pad produced by feed motor 26 overrun after the motor is turned off. If the constants K, and K 2 are known for a conversion machine, the Iength of pad produced by the machine can thus be accurately controlled by monitoring the encoder pulses. Considering, for example, a cushioning conversion machine having a Iength sensor, such as one of the encoders 21 4 or 21 4' described above relative to Figures 1 8 and 1 9, respectively, the Iength of a pad is determined by the controller 1 8 which multiplies the number of encoder pulses received from the encoder by the constant K, and adds to the product the constant l< 2 . Other encoders can also be used such as that described in pending U.S. Patent No. 5,571 ,067 which sense the rotation of the drive gears 44 and 46 or encoders which sense the rotation or linear movement of other parts of the cushioning conversion machine, such as the drive shaft 42, from which pad Iength production can be inferred. The constants K, and K 2 are determined through the use of a second sensor, such as the optical sensor 242 described above relative to Figure 23, positioned a known distance from the blade of the severing assembly 1 6. The optical sensor 242 can be placed anywhere along the output extension 246 provided that the controller 1 8 is provided with this known distance. Preferably, the optical sensor 242 is located generally around eight to twelve inches from the blade of the severing assembly 1 6 as this is a typical pad Iength range although other distances can of course be used. To perform a calibration procedure, the controller 1 8 turns on the motor 26 and counts the number of pulses received from the encoder 21 4 until the optical sensor 242 detects the end of a pad . The controller 1 8 then calculates the constant K^ as follows: K 7 = distance between blade and optical sensor 242 recorded encoder 214 pulses The controller 1 8 will continue to leave the feed motor 26 running until the desired or preset pad Iength is produced whereupon the controller 1 8 will turn off the feed motor. After the feed motor 26 is turned off the controller 1 8 will then record the number of additional pulses received from the encoder 21 4 due to feed motor overrun, etc. The controller 1 8 can then calculate the constant K 2 as follows: K 2 = K 1 * (additional recorded encoder 214 pulses) The controller 1 8 in producing further pads may then use the updated values of the constants K-, and K 2 to calculate pad Iength. Alternatively, a number of calibration procedures could be performed with the averages of the constants taken before the constants are updated . This provides the advantage that a single calibration procedure does not result in a significant difference in the pad iength calculation. The system is thus less susceptible to errors in a calibration procedure due to disturbances in the calibration technique or interference by the operator, for example. Other automated calibration systems could also be employed. For example, the pad Iength measuring system 14t of Figure 22 described above could be used in a fashion where the series of optical sensors 236 provide to the controller 1 8 an indication of actual pad Iength from which the controller 1 8 could determine a correction factor. To explain, if the optical sensors 236 are located at a known distance from the blade of the severing assembly 1 6 and at a known spacing, such as a one inch spacing, when the controller 1 8 instructs the feed motor 26 to produce a 1 2 inch pad, for example, the outputs of the optical sensors can be examined by the controller to determine the actual Iength of the pad produced to an accuracy constrained by the spacing of the sensors. The controller 1 8 can then make any necessary corrections to produce an appropriately lengthened pad. One may now appreciate that the present invention provides a Iength measuring device which may be used in conjunction with a sophisticated packaging program. Although the invention has been shown and described with respect to a certain preferred embodiment, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such equivalent alterations and modifications and is limited only by the scope of the following claims.

Claims: What is claimed is: 1 . A cushioning conversion machine for converting a sheet-like stock material into a three-dimensional cushioning pad of a desired post-conversion parameter, said machine comprising: a conversion assembly which converts the stock material into the cushioning pad; a stock supply assembly which supplies the sheet-like stock material to the conversion assembly; an input device which receives an input of the desired post-conversion parameter; a controlling device which controls the conversion assembly based on the stock supplied thereto to produce a pad of the inputted desired parameter. 2. A cushioning conversion machine as set forth in claim 1 further comprising a stock supply monitoring device which monitors a pre-conversion property of the stock material supplied to the conversion assembly. 3. A cushioning conversion machine as set forth in claim 2 wherein the post-conversion parameter received by the input device is the desired pad iength and wherein the controlling device includes a translator which translates the pre-conversion property into the desired post-conversion pad Iength. 4. A cushioning conversion machine as set forth in claim 3 wherein the stock supply monitoring device measures the Iength of the stock material supplied to the conversion assembly whereby the pre-conversion property is the Iength of the stock material supplied to the conversion assembly. 5. A cushioning conversion machine as set forth in claim 4 wherein the stock supply monitoring device directly measures the Iength of the stock material supplied to the conversion assembly. 6. A cushioning conversion machine as set forth in claim 5 wherein the stock supply monitoring device includes: a measuring device which directly measures the stock material as it is supplied from the stock supply to the conversion assembly; and a relay which relays the direct measurement of the stock material to the controlling device whereby it controls the conversion assembly based on the direct measurement to produce a pad of the desired post-conversion parameter. 7. A cushioning conversion machine as set forth in claim 5 wherein the stock supply monitoring device includes: a sensor which detects the occurrence of indicia on the stock material; and a relay which relays the occurrence of indicia to the controlling device whereby it controls the conversion assembly based on the occurrence of indicia to produce a pad of the desired post-conversion parameter. 8. A cushioning conversion machine as set forth in claim 5 wherein the stock supply monitoring device includes: a light transmitter for directing light incident on the stock material; a light detector for detecting the occurrence of openings in the stock material; and a relay which relays the occurrence of openings to the controlling device whereby it controls the conversion assembly based on the occurrence of openings to produce a pad of the desired post~ conversion parameter. 9. A cushioning conversion machine as set forth in claim 4 wherein the stock supply monitoring device indirectly measures the Iength of the stock material supplied to the conversion assembly. 1 0. A cushioning conversion machine as set forth in claim 9, wherein: the stock supply assembly includes a dispenser which dispenses slack stock material from the stock supply; the stock supply monitoring device includes a measuring device which measures the amount of slack stock material, and a relay which relays the amount of slack stock material to the controlling device whereby it controls the conversion assembly based on the amount of slack stock material to produce a pad of the desired post-conversion parameter. 1 1 . A cushioning conversion machine as set forth in claim 3 wherein the stock supply monitoring device monitors the differential of stock material as it is supplied to the conversion assembly. 1 2. A cushioning conversion machine as set forth in claim 1 1 wherein the stock supply monitoring device includes: a measuring device which measures a change in a dimension of the stock material as it is supplied to the conversion assembly; and a relay which relays the change in dimension to the controlling device whereby it controls the conversion assembly based on the change in dimension of the stock supply to produce a pad of the desired post- conversion parameter. 1 3. A cushioning conversion machine as set forth in claim 1 2 wherein the dimension of the stock material is a radius. 14. A cushioning conversion machine as set forth in claim 1 2 wherein the dimension of the stock material is a height 1 5. A cushioning conversion machine as set forth in claim 1 1 wherein the stock supply monitoring device includes: a scale which measures a change in the weight of the stock material as it is supplied to the conversion assembly; and a relay which relays the change in weight to the controlling device whereby it controls the conversion assembly based on the change in weight of the stock material to produce a pad of the desired post-conversion parameter. 1 6. A cushioning conversion machine as set forth in claim 4, wherein: the stock supply assembly includes a dispenser which dispenses slack stock material from the stock supply; the controlling device activates the dispenser for a period of rime corresponding to the inputted pad Iength; the stock supply monitoring device includes a sensor which senses the absence/presence of slack stock material and a relay which relays the absence/presence of slack stock material to the controlling device whereby it controls the conversion assembly based on the absence/presence of slack stock material to produce a pad of the desired post-conversion parameter. 1 7. A cushioning conversion machine as set forth in claim 2 wherein the post-conversion parameter received by the input device is the desired pad weight. 1 8. A cushioning conversion machine as set forth in claim 1 7 wherein the stock supply monitoring device includes: a scale which measures a change in the weight of the stock material as it is supplied to the conversion assembly; and a relay which relays the change in weight to the controlling device whereby it controls the conversion assembly based on the change in weight of the stock material to produce a pad of the desired post-conversion parameter. 1 9. A cushioning conversion machine as set forth in claim 2 wherein: the stock supply assembly includes a dispenser which allows manual dispersement of slack stock material; the input device includes a translation device which is positioned for measuring the manual dispersement of the stock material and which translates the manual dispersement into the desired post-conversion parameter; and the stock supply monitoring device includes a sensor which senses the absence/presence of slack stock material and a relay which relays the absence/presence of slack stock material to the controlling device whereby it controls the conversion assembly based on the absence/presence of slack stock material to produce a pad of the desired post-conversion parameter. 20. A cushioning conversion machine as set forth in claim 1 ; wherein the conversion assembly comprises a forming assembly which forms the sheet-like stock material into a strip, a feed assembly which feeds the sheet-like stock material through the forming assembly, and a severing assembly which severs the strip into sections; and wherein the controlling device controls the feed assembly. 21 . A cushioning conversion machine as set forth in claim 20 wherein the controlling device also controls the cutting assembly. 22. A cushioning conversion machine for converting a sheet-like stock material into a three-dimensional cushioning pad of a desired post-conversion parameter, said machine comprising a conversion assembly, a stock supply assembly, an input device, a conversion monitoring device, and a pad production controlling device; the conversion assembly converting the stock material into the cushioning pad and being powered by a feed motor; the stock supply assembly supplying the sheet-like stock material to the conversion assembly; the input device receiving an input of the desired post-conversion parameter; the conversion monitoring device including a reservoir which accumulates a fluid based on the operation of the feed motor, a sensor for sensing the amount of fluid in the reservoir, and a relay which relays the amount of fluid in the reservoir to the controlling device; and the controlling device controlling the conversion assembly based on the amount of fluid in the reservoir to produce a pad of the inputted desired parameter. 23. A cushioning conversion machine as set forth in claim 22 wherein the post-conversion parameter received by the input device is the desired pad Iength and wherein the controlling device includes a translator which translates the amount of fluid in the reservoir into the desired pad Iength. 24. A cushioning conversion machine as set forth in claim 23 wherein the conversion monitoring device also includes a pump which delivers fluid into the reservoir at a rate corresponding to the operation of the feed motor; and wherein the sensor includes a switch which activates the relay when amount of fluid in the reservoir corresponds to the inputted post-conversion parameter. 25. A cushioning conversion machine as set forth in claim 24 wherein the pump delivers a gas into the reservoir and wherein the sensor senses the pressure of the reservoir. 26. A cushioning conversion machine as set forth In claim 24 wherein the pump delivers a liquid into the reservoir and wherein the sensor senses the level of liquid in the reservoir. 27. A cushioning conversion machine as set forth in claim 22; wherein the conversion assembly comprises a forming assembly which forms the sheet-like stock material into a strip, a feed assembly which feeds the sheet-like stock material through the forming assembly and which is powered by the feed motor, and a severing assembly which severs the strip into sections; and wherein the controlling device controls the feed assembly. 28. A cushioning conversion machine as set forth in claim 27 wherein the controlling device also controls the severing assembly. 29. A cushioning conversion machine for converting a sheet-like stock material into a three-dimensional cushioning pad of a desired parameter, said machine comprising: a conversion assembly which converts the stock material into the cushioning pad and which is powered by a feed device activatable in predetermined increments; a stock supply assembly which supplies the sheet-like stock material to the conversion assembly; an input device which receives an input of the desired post-conversion parameter; and the controlling device which controls operation of the feed device by activating the feed device for a number of increments corresponding to the desired post-conversion parameter. 30. A cushioning conversion machine as set forth in claim 29 wherein the post-conversion parameter received by the input device is the desired pad Iength. 31 . A cushioning conversion machine as set forth in claim 30 wherein the feed device comprises a stepper motor which includes a plurality of steps in each rotation and wherein the stepper motor is activated by the controlling device for a number of increments corresponding to the desired pad Iength. 32. A cushioning conversion machine as set forth in claim 30 wherein the feed device comprises a feed motor and a clutch which includes a plurality of stops for selective engagement with the feed motor for each rotation and wherein the clutch is engaged with the feed motor for a number of increments corresponding to the desired pad Iength. 33. A cushioning conversion machine as set forth in claim 29; wherein the conversion assembly comprises a forming assembly which forms the sheet-like stock material into a strip, a feed assembly which feeds the sheet-like stock material through the forming assembly and which is powered by the feed device, and a severing assembly which severs the strip into sections; and wherein the controlling device controls the feed assembly. 34. A cushioning conversion machine as set forth in claim 33 wherein the controlling device also controls the cutting assembly. 35. A cushioning conversion machine for converting a sheet-like stock material into a three-dimensional cushioning pad of a desired parameter, said machine comprising a conversion assembly, a stock supply assembly, an input device, a conversion monitoring device, and a pad production controlling device; the conversion assembly converting the stock material into the cushioning pad and being powered by a feed motor; the stock supply assembly supplying the sheet-like stock material to the conversion assembly; the input device receiving an input of the desired parameter; the conversion monitoring device including a meter for tracking the amount of power supplied to the feed motor and a relay which relays the amount of power to the controlling device; and the controlling device controlling the conversion assembly based on the amount of power supplied to the feed motor to produce a pad of the inputted desired parameter. 36. A cushioning conversion machine as set forth in claim 35 wherein the post-conversion parameter received by the input device is the desired pad Iength. 37. A cushioning conversion machine as set forth in claim 36; wherein the conversion assembly comprises a forming assembly which forms the sheet-like stock material into a strip, a feed assembly which feeds the sheet-like stock material through the forming assembly and which is powered by the feed device and a severing assembly which severs the strip into sections; and wherein the controlling device controls the feed assembly. 38. A cushioning conversion machine as set forth in claim 37 wherein the controlling device also controls the cutting assembly. 39. A cushioning conversion machine for converting a sheet-like stock material into a three-dimensional cushioning pad of a desired post-conversion parameter, said machine comprising: a conversion assembly which converts the stock material into the cushioning pad; a stock supply assembly which supplies the sheet-like stock material to the conversion assembly; an input device which receives an input of the desired post-conversion parameter; a post-conversion monitoring device which monitors a post-conversion property of the pad; a controlling device which controls the conversion assembly based on the post-conversion property to produce a pad of the inputted desired parameter. 40. A cushioning conversion machine as set forth in claim 39 wherein the post-conversion parameter received by the input device is the desired pad Iength. 41 . A cushioning conversion machine as set forth in claim. 40 wherein the post-conversion monitoring device measures the Iength of the pad produced by the conversion assembly. 42. A cushioning conversion machine as set forth in claim 41 wherein the post-conversion monitoring device comprises: a measuring device which directly measures the pad produced by the conversion assembly; a relay which relays the direct measurement to the controlling device whereby it controls the conversion assembly based on the direct measurement to produce a pad of the desired Iength. 43. A cushioning conversion machine as set forth in claim 42 wherein the conversion assembly includes a severing assembly and wherein the measuring device is positioned upstream of the severing assembly. 44. A cushioning conversion machine as set forth in claim 42 wherein the conversion assembly includes a severing assembly and wherein the measuring device is positioned downstream of the severing assembly. 45. A cushioning conversion machine as set forth in claim 41 wherein the conversion assembly produces predeterminedly spaced openings on the pad and wherein the post-conversion monitoring device includes: a light transmitter for directing light incident on the pad; a light detector for detecting the occurrence of the openings; and a relay which relays the occurrence of openings to the controlling device whereby it controls the conversion assembly based on the occurrence of openings to produce a pad of the desired Iength. 46. A cushioning conversion machine as set forth in claim 41 wherein the conversion assembly produces predeterminedly spaced indicia on the pad and wherein the post-conversion monitoring device includes: a sensor which detects the occurrence of indicia on the stock material; and a relay which relays the occurrence of indicia to the controlling device whereby it controls the conversion assembly based on the occurrence of indicia to produce a pad of the desired Iength. 47. A cushioning conversion machine as set forth in claim 40 wherein the post-conversion monitoring device includes: a linear array of sensors which are arranged at positions corresponding to predetermined pad lengths and which each detect the presence/absence of pad; and a relay which relays the presence/absence of the pad at each sensor to the controlling device whereby it controls the conversion assembly based on the absence/presence of the pad at each sensor to produce a pad of the desired Iength. 48. A cushioning conversion machine as set forth in claim 40 wherein the post-cutting monitoring device includes: a contact which engages the leading end of the pad and travels therewith as the pad is being produced by the conversion assembly; a sensor which senses the position of the contact; and a relay which relays the position of the contact to the controlling device whereby it controls the conversion assembly based on the position of the contact to produce a pad of the desired Iength. 49. A cushioning conversion machine as set forth in claim 40 wherein the input device includes a marker manually locatable in a range of positions corresponding to a range of pad lengths and wherein the post- conversion monitoring device includes: a sensor attached to the marker which senses the absence/presence of the pad at the marker; and a relay which relays the presence/absence of the pad at the marker to the controlling device whereby it controls the conversion assembly based on the absence/presence of the pad at the marker to produce a pad of the desired Iength. 50. A cushioning conversion machine as set forth in claim 40 wherein the post-conversion monitoring device includes: a scale which measures the weight of the pad; and a relay which relays the weight of the pad to the controlling device whereby it controls the, conversion assembly based on the weight of the pad to produce the pad of the desired Iength. 51 . A cushioning conversion machine as set forth in claim 39 wherein the post-conversion parameter received by the input device is the desired pad weight. 52. A cushioning conversion machine as set forth in claim 51 wherein the post-conversion monitoring device includes: a scale which measures the weight of the pad; and a relay which relays the weight of the pad to the controlling device whereby it controls the conversion assembly based on the weight of the pad to produce the pad of the desired weight. 53. A cushioning conversion machine as set forth in claim 39; wherein the conversion assembly comprises a forming assembly which forms the sheet-like stock material into a strip, a feed assembly which feeds the sheet-like stock material through the forming assembly and which is powered by the feed device, and a severing assembly which severs the strip into sections; and wherein the controlling device controls the feed assembly. 54. A cushioning conversion machine as set forth in claim 53 wherein the controlling device also controls the severing assembly. 55. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a roller which rolls along the stock material as it is fed from the supply roll and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to approximate the Iength of cushioning material produced as a function of the rotation of the roller. 56. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a probe which contacts a point on the outer radius of the supply roll and a position sensor which senses the position of the probe relative to a known point and which communicates the position of the probe to the controller to approximate the Iength of cushioning product produced as a function of the change in the radius of the stock supply roll. 57. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stack of generally fan-folded stock material through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a probe which contacts the stack of stock material and a position sensor for sensing the position of the probe and communicating the position of the probe to the controller to approximate the Iength of cushioning product produced as a function of the change in the height of the stack of supply material. 58. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stack of generally fan-folded stock material through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a sensor which senses the removal of a fold of paper beneath the probe and communicates the removal to the controller to approximate the Iength of cushioning product produced as a function of the removal of folds of stock material from the stack of stock material. 59. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a sensor for detecting the occurrence of indicia recorded on the stock material as the material is fed past the sensor and for communicating the detection of the occurrence of the indicia to the controller to approximate the Iength of cushioning product produced as a function of the number of indicia detected. 60. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a light transmitter for directing light incident on the stock material and a light detector for detecting the occurrence of perforations in the stock material as a function of reflected light as the material is fed past the sensor and for communicating the detection of the occurrence of the perforations to the controller to approximate the Iength of cushioning product produced as a function of the number of perforations detected. 61 . A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including scale for measuring the weight of the stock supply roll and for communicating the weight of the stock supply to the controller to approximate the Iength of cushioning product produced as a function of the change in weight of the stock supply. 62. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined weight, and a weight measuring device including scale for measuring the weight of the supply roll and for communicating the weight of the roll to the controller to cause the feed motor to stop when the change in the measured weight reaches the predetermined weight. 63. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; and a Iength measuring device including a unwinder for unwinding a desired Iength of stock material from the roll, and a sensor switch for indicating the presence of stock material unwound from the roll and for causing the feed assembly to feed stock material through the forming assembly while the sensor detects the presence of unwound stock material. 64. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller, and a Iength measuring device including an unwinder for unwinding a desired Iength of stock material from the roll and a linear array of sensors, each sensor of the array for detecting the presence of stock material adjacent the sensor and communicating such detection to the controller, and wherein the controller controls the unwinder and the feed assembly in accordance with the communications from the linear array of sensors to produce a cushioning product of a predetermined Iength. 65. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a severing assembly for severing the stock material fed through the conversion assembly to form a discrete cushioning product; and a Iength measuring device including a reticle permitting the measurement of stock material manually unwound from the supply roll, and a sensor switch for indicating the presence of stock material unwound from the roll and for causing the feed assembly to feed stock material through the forming assembly while the sensor detects the presence of unwound stock material. 66. The cushioning conversion assembly of claim 65, wherein the sensor switch causes the severing assembly to sever the stock material after the sensor detects the absence of unwound stock material. 67. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly powered by a feed motor for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a pump powered by the feed motor for generating pressurized air, a reservoir for accumulating the pressurized air and a pressure sensor which senses the level of pressure in the reservoir and a switch for communicating to the controller the occurrence of the sensed pressure reaching a value which corresponds to the predetermined Iength of cushioning product to be produced. 68. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly powered by a feed motor for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a pump powered by the feed motor for introducing fluid to a reservoir and a level sensor which senses the level of fluid in the reservoir and a switch for communicating to the controller the occurrence of the sensed level reaching a value which corresponds to the predetermined Iength of cushioning product to be produced. 69. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly powered by a stepper motor for feeding stock material from a stock supply roll through the forming assembly; a Iength input device permitting the entry by an operator of a desired Iength of cushioning material to be produced; and a controller for controlling operation of the stepper motor through pulses generated in accordance with the desired Iength entered through the Iength input device. 70. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; a feed motor for powering the feed assembly; a clutch assembly for selectively engaging the feed assembly with the feed motor to cause a specified Iength of cushioning product to be fed through the forming assembly; and a controller for controlling operation of the clutch assembly. 71 . A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly powered by a feed motor for feeding stock material from a stock supply through the forming assembly; a power sensor for sensing the amount of power supplied to the feed motor; a Iength input device permitting the entry by an operator of a desired Iength of cushioning product to be produced; and a controller for correlating the desired Iength of cushioning product to be produced to the required amount of power necessary to supply to the feed motor for it to feed the appropriate Iength of stock material through the forming assembly to produce the desired Iength of cushioning product and for controlling the supply of power to the feed motor in accordance with the Iength of cushioning product to be produced and the cumulative amount of power supplied to the feed motor as sensed by the power sensor. 72. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; a severing assembly for severing the continuous strip of cushioning product into a discrete Iength of cushioning product; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength; and a Iength measuring device including a roller which rolls along the cushioning product after it is formed and prior to being severed, and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to determine the iength of cushioning material produced as a function of the rotation of the roller. 73. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; a severing assembly for severing the continuous strip of cushioning product into a discrete Iength of cushioning product; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength; and a Iength measuring device including a roller which rolls along the cushioning product downstream of the severing assembly, and a sensor which senses the rotation of the roller and communicates the amount of rotation to the controller to determine the Iength of cushioning material produced as a function of the rotation of the roller. 74. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; an assembly for forming indicia on the cushioning product; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength; and a Iength measuring device including a sensor which detects the occurrence of indicia on the cushioning material and which communicates such occurrences to the controller to determine the Iength of cushioning material produced as a function of the number of occurrences of indicia detected. 75. The cushioning conversion machine of claim 74, wherein the indicia is printed on the cushioning product as it is formed. 76. The cushioning conversion machine of claim 74, wherein the indicia is printed on stock material. 77. The cushioning conversion machine of claim 74, wherein the indicia includes perforations made in the cushioning product as it is formed . 78. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly and through an output of the machine; a controller, and a Iength measuring device including a linear array of sensors arranged at the output of the machine, each sensor of the array for detecting the presence of different lengths of cushioning product and communicating such detection to the controller, and wherein the controller controls the feed assembly in accordance with the communications from the linear array of sensors to produce a cushioning product of a predetermined Iength. 79. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly; a severing assembly for severing the continuous strip of cushioning product into a discrete Iength of cushioning product; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength; and a Iength measuring device including a sensor locatable at an adjustable distance from the severing assembly which detects the presence or absence of cushioning material adjacent the sensor and which communicates the detection of the cushioning material to the controller. 80. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly and through an outlet; a severing assembly for severing the continuous strip of cushioning product into a discrete iength of cushioning product; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength; and a Iength measuring device including a contact positioned at the outlet for engaging the leading edge of the continuous strip of cushioning product and movable with the cushioning product as it progresses from the exit, and a sensor for sensing the position of the contact and communicating the position of the contact to the controller. 81 . A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of a cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly and through a machine outlet; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including scale positioned at the outlet for measuring the weight of the continuous strip of cushioning product and for communicating the weight of the cushioning product to the controller to approximate the Iength of cushioning product produced as a function of its weight. 82. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a continuous strip of a cushioning product; a feed assembly for feeding stock material from a stock supply through the forming assembly and through a machine outlet; a weight input allowing an operator to select the weight of the cushioning material to be produced; a controller for controlling operation of the feed assembly to produce a cushioning product of the selected weight, and a weight measuring device including scale positioned at the outlet for measuring the weight of the continuous strip of cushioning product and for communicating the weight of the cushioning product to the controller. 83. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly, the feed assembly including at least one rotating component; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a velocity sensor for sensing the velocity of the rotating component and communicating the velocity to the controller to calculate the Iength of cushioning product produced as a function of integral of velocity over time. 84. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from a stock supply roll through the forming assembly; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and a Iength measuring device including a velocity sensor for sensing the velocity of stock material through the machine and for communicating the velocity to the controller to calculate the the Iength of cushioning product produced as a function of integral of velocity over time. 85. A cushioning conversion machine comprising: a forming assembly which converts a stock material into a cushioning product; a feed assembly for feeding stock material from supply through the forming assembly; a encoder for generating a series of pulses corresponding generally to the Iength of pad formed; a controller for controlling operation of the feed assembly to produce a cushioning product of a predetermined Iength, and and an automated Iength calibration mechanism including a Iength measuring sensor for measuring the Iength of a pad after formation. 86. A method of calibrating a cushioning conversion machine, comprising the steps of: generating and recording a series of pulses inferring the Iength of pad being produced by the cushioning conversion machine; measuring the Iength of the pad actually produced at the output of the machine; and determining at least one correction factor to correlate the number of 5 pulses recorded to the Iength of a pad actually produced. 87. A method of calibrating a cushioning conversion machine, comprising the steps of: controlling a feed assembly including a feed motor to produce a pad of a predetermined Iength; 0 generating a series of pulses inferring the Iength of pad being produced by the cushioning conversion machine by the movement of the feed assembly and recording the number of such pulses until the feed motor has been instructed to stop; measuring the Iength of the pad actually produced at the output of the 1 5 machine; recording the number of pulses generated after the feed motor has been instructed to stop; and determining at least one correction factor to correlate the number of pulses recorded to the Iength of a pad actually produced. on * * *

Inventors: FOGG DANIEL T, GUTH PAUL J, HARDING JOSEPH J, LENCOSKI MICHAEL J, RATZEL RICHARD O, SIMMONS JAMES A, FOGG, DANIEL, T., GUTH, PAUL, J., HARDING, JOSEPH, J., LENCOSKI, MICHAEL, J., RATZEL, RICHARD, O., SIMMONS, JAMES, A.
Applicants: FOGG DANIEL T, GUTH PAUL J, HARDING JOSEPH J, LENCOSKI MICHAEL J, RANPAK CORP, RATZEL RICHARD O, SIMMONS JAMES A, FOGG, DANIEL, T., GUTH, PAUL, J., HARDING, JOSEPH, J., LENCOSKI, MICHAEL, J., RANPAK CORP., RATZEL, RICHARD, O., SIMMONS, JAMES, A.
Application year: 1998
Main classification: B31D5
IPC codes: B31D5