Abstract:
A continuous splicer includes first and second closely spaced rotating cylinders each having a respective cutting element and tape retaining arrangement disposed on its outer periphery. With a depleting web fed by the first cylinder and a replenishing web fed by the second cylinder, an end of the replenishing web is adhesively joined to the depleting web while in motion and the depleting web is severed by the first cylinder&#39;s cutting element in forming a splice of the two webs. As the replenishing web depletes, a third web may be inserted on the first cylinder and automatically or manually spliced to the original replenishing web without stopping or re-configuring the splicer. The splicer is capable of delivering the webs at a constant rate or a rapidly changing and/or dynamic cycling rate, and applies relatively low web tension for operation with delicate, narrow and extensible webs.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/147,563 filed Jan. 27, 2009 for “APPARATUS FOR SPLICING WEBS”. 
    
    
     FIELD OF THE INVENTION 
     The present invention provides an improved splicing apparatus and method, suitable for handling a wide range of materials, web widths, and web thicknesses. It is particularly suitable for handling relatively delicate webs of paper or poly film material. 
     BACKGROUND OF THE INVENTION 
     Summary of prior art splicers: Many of the prior art unwinding (i.e., supplying rather than rewinding) splicers are zero-speed splicers, that is the depleting web is stopped and joined to a prepared, stationary replenishing web. The supply of web to a web consuming device may continue uninterrupted as web is taken from a stored supply of web in a festoon or accumulator. Most of these zero-speed splicers use a cutter that cuts the web with a transverse motion, in a reciprocating cycle. 
     There are also “flying” splicers and these make a splice by matching the speeds of two webs and then joining them together. These “flying” splicers require costly drive systems and controls. 
     SUMMARY OF THE INVENTION 
     The present invention provides an unwind/splicer that delivers a web at continuous, relatively constant rate or rapidly changing and/or cycling, dynamic rate in response to like demand with minimal tension variation. 
     An unwind/splicer delivers web at relatively low tension to allow handling of delicate, narrow, and or extensible (stretchy) webs such as thin materials like paper or poly and especially narrow width, minimal thickness, i.e., down to about ½ mil (0.0005″ or 13 micron) commonly used in windowing operations performed by the Vista™ window applicator made by Tamarack Products Inc, Wauconda, Ill., USA for use on carton folder/gluers, or web finishing systems such as those provided the Versa-Web® machine, also of Tamarack Products Inc. 
     The invention includes a splicer that makes running splices as opposed to zero-speed splices and, further, does so with minimal effect on web tension. The splicer makes rapid splices thereby consuming a relatively small amount of web from an accumulator. The splicer can be manually, crank-operated or can be equipped for automatic operation. The splicer provides a lap or butt splicer that simultaneously cuts the expiring web while joining the prepared (i.e., pre-taped leading edge), replenishing web. The instant splicer includes a simplified mechanism compared to prior art splicers. It eliminates clamping bars and the complications of prior art sequencing clamping bars with cutting and other operations. Further, the instant splicer is compatible with either two-sided or single-side adhesive splicing tapes, and it uses rotary cutting rather than reciprocating, transverse cutting wheels/blades or shear cutting blades/anvils. The instant splicer uses inexpensive cutting blades, and the blades which are easy to replace. 
     Twin cylinders locate the cutting blades and vacuum surfaces for securing the tape and leading edge of the replenishing web. 
     Further, a simple rolling action of the splicing cylinders provides the key functions and sequencing of the splicing operation:
         Supports the splicing tape and lead end of the replenishing web.   Advances the replenishing web towards the depleting web.   Rolls the tape and lead end of replenishing web into contact with the depleting web, at an inherently, approximately-matched speed.   Drives an anvil strip between the depleting web and replenishing web via a simple crank/slider mechanism. The anvil strip provides two functions: one side acts as an anvil surface for cutting the depleting web against, the other side acts as a shield to prevent cutting the replenishing web   Cuts the depleting web with a rolling motion rather than a reciprocating knife motion.   Releases the replenishing and depleting webs as splicing cylinders roll out of contact.   Retracts the anvil strip, again using a simple crank/slider mechanism.       

     A reciprocating anvil strip is interposed between the cutting cylinders when a cut is needed, and then retracted when it is not needed, and without support by a belt. 
     In the instant invention, the anvil strip is only interposed between the cylinders when a cut is being effected. And the anvil strip is used in a unique way: One side of the anvil strip serves as a cutting anvil surface for cutting one web. The other side of the anvil strip simultaneously and advantageously protects a second web from being cut. 
     The reciprocating anvil strip both moves the anvil strip clear of the web while web is consumed by the host machine, and approximately matches the anvil strip velocity with the cutting blade velocity. This reduces wear on both the anvil strip and cutting blade. 
     The instant invention provides an elegantly simple method of making a ‘flying splice’ by providing a small amount of ‘stored’ web to assure that the replenishing web is readily accelerated to approximately the speed of the expiring web and that the leading end of the replenishing web is joined in close proximity to the cut tail end of the expiring web. This eliminates the need for sophisticated controls and drives for matching the speed of the webs during the splice. The instant invention simply has a small amount of slack web without the guiding and controlling mechanism of some prior art devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will be best be understood by reference to the following detailed description of a preferred embodiments taken in conjunction with the accompanying drawings, where like reference characters identify like elements throughout the various figures, in which; 
         FIG. 1  is a simplified schematic illustration of a web supply arrangement incorporating the continuous web splicer of the present invention; 
         FIG. 2  is a simplified schematic illustration of a carriage and spindle drive control system for use with the continuous splicer apparatus of the present invention; 
         FIGS. 3   a - 3   e  illustrate the sequence of movements and operations in splicing a replenishing web to a depleting web carried out by the splicing cylinders and idler rollers of the continuous splicer apparatus of the present invention; 
         FIGS. 4   a  and  4   b  are respectively simplified schematic end and front views of a splicing assembly for use in the continuous splicer apparatus of the present invention; 
         FIGS. 5   a - 5   e  are end views of an alternative embodiment of a splicing assembly for use in the continuous splicer apparatus of the present invention; and 
         FIG. 6  is a front view of the splicing assembly shown in  FIGS. 5   a - 5   e.    
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A web unwinding and splicer apparatus  10 , shown in  FIG. 1  illustrates a general configuration, including roll unwind spindles  11  and  12 , and accumulator  13  supported by conventional frame work. The apparatus  10  also includes mirror-image splicing heads  14  and  15  as part of a splicing apparatus  23 . The splicing heads  14  and  15  are configured to provide a novel and inventive rolling splicing process, as will be disclosed herein. 
     In operation, one of the spindles  11  or  12  is supplying web  18  to the accumulator  13  and in turn, supplies the web  18  to whatever web consuming machinery the apparatus  10  is connected to, such as a Vista® window applicating machine manufactured by Tamarack Products Inc. of Wauconda, Ill. For example, spindle  11  is supplying web  18  from a roll of web material  11   a  and roll  11   a  will eventually be depleted. Splicing head  15  is prepared with the lead end of a replenishing roll  12   a  on spindle  12 . When roll  11   a  is nearly depleted, the splicing mechanism  23  splices web material from roll  12   a  on spindle  12  to web  18  and essentially concurrently severs the web from roll  11   a.    
     While the roll  12   a  is running, the apparatus  10  may then be provided with a new roll of material on spindle  11 , and splicing head  14  of splicing mechanism  23  may then be prepared with web from roll  11   a  to allow it to be spliced to web  18  when roll  12  a is depleted. In this alternating manner of running from one spindle while preparing the other spindle to provide a replenishing supply, the apparatus  10  can continuously provide a continuous running web  18  to a web consuming device. 
     Accumulator  13 , while of a conventional general configuration, includes features to adapt it to controlling webs of materials that are prone to tearing, such as acetate film with thicknesses as thin as approximately 1 mil (0.001″), or less, and thin polyethylene films which are relatively extensible (elastic, stretchy). Such delicate film webs, can be even more difficult to handle, when they have a relatively narrow width, e.g., 2-4 in.″, which are sometimes encountered when applying window patches to folding cartons. The combination of material characteristics, such as low tensile strength and high notch sensitivity, combined with minimal thickness and narrow web width combine to make web handling difficult and prone to interruptions from web breaks. A web consuming device such as a Tamarack® Vista® window applicator, which operates in a stop-and-go manner, further exaggerates the tendency to stretch or break a delicate web. The instant invention utilizes lightweight components such as thin-wall rollers  16  with low friction bearings, particularly at the lower, moving carriage  17  where the low mass of each roller reduces the vertical force and the rotational inertia. This makes the accumulator  13  more suitable for supplying a delicate web material. 
     In some cases thin-wall rollers  16  may be replaced with air bars which are stationary, but ‘float’ the web  18  by virtue of a supply of compressed air to the outer surface of the each bar. This compressed air is trapped to an extent by the web  18  as it wraps around the bars. ‘Floating’ the web  18  around each turn bar provides a very low friction conveyance of the web  18  through the accumulator assembly. In practice, however, air bars, of course, require energy-intensive compressed air, may be prone to clogging, and some web disturbances, such as a wrinkle may cause a momentary failure of the air flotation and a consequent moment of high drag and web breakage. Further, unused portions of air bars are typically wrapped or taped to conserve compressed air, and such masking and adhesive residue must be cleaned off when changing the set up to another web width. Web tracking control around multiple air bars can be problematic; even slight misalignments can cause large tracking errors. 
     The accumulator carriage  17  is free to move up, to supply web from the accumulator, or down to absorb web into the accumulator. The movement of carriage  17  is sensed and its position is used to control spindle brakes  11   b ,  12   b , one on each of the unwind spindles  11 ,  12  to control the web tension and the delivery of web material to the accumulator  13 . The carriage  17  has a low-friction guiding and support system, for example, a series of ball bearings engaging a vertical bar or shaft. The carriage is constructed of lightweight materials, such as aluminum, with component sizes minimized according to the loads they encounter, for a low-mass construction. This reduces web tension variation as the carriage moves up and down, potentially in response to rapidly changing web  18  motions, such as the aforementioned stop-and-go web consumption of a Tamarack Vista window applicator. 
     Referring now to  FIG. 2 , a schematic representation of the carriage and spindle drive control system, the accumulator carriage  17  is connected via a toothed belt  201  or lightweight chain, cable, or the like, to a Kinax® (GMC-I Messtechnik GmbH, Nuremberg, Germany) encoder  202 . The Kinax encoder provides an electrical signal representative of the position of the carriage  17 . At the bottom of the carriage&#39;s travel, a larger signal is produced, at the top of the carriage&#39;s travel, a smaller signal is produced. 
     The signal from the Kinax encoder is used as an input by a Proportion-Air® (McCordsville, Ind.) air pressure regulator  203 . With a larger signal input signal, i.e., when the carriage is at the bottom of its travel, the regulator  203  sends approximately 50 psi to both brakes,  11   b ,  12   b . The air pressure results in a braking force at each unwind spindle,  11 ,  12 . This causes a reduction in the rate of web supplied to the accumulator  13 , and an increase in web tension. 
     As the carriage  17  rises in response to the brake application or an increase in the rate of web consumption by the web consuming device, the signal from the encoder  202  reduces, thus reducing the pressure applied to both brakes  11   b ,  12   b . When the system is adjusted properly, the carriage  17  will operate in the bottom ⅓ of the range of available travel, thus modulating the supply of web material to the web consuming device. With the carriage in the bottom ⅓ of travel, there is also sufficient storage of web  18  in the accumulator  13  to allow for a splicing event, during which there is some brief interruption to the supply of web from the unwinds  11  or  12 . When the web consuming device operates in an intermittent, i.e., stop-and-go manner, the low-inertia carriage  17  is free to move up and down slightly, with minimal change in web tension, while isolating the intermittent feeding of web  18  out of the accumulator  13  from the relatively high inertia, relatively steady rotation of the supplying roll  11   a  or  12   a.    
     The same pressure may be sent to both brakes  11   b ,  12   b . This is satisfactory because only one of the spindles  11  or  12  is supplying web  18 , while the other spindle is stationary, awaiting a splice event to splice a replenishing supply of web from its roll of web material. In other words, varying the braking on the stationary spindle has no effect on the system operation. 
     To assist in the goal of delivering web  18  with reduced web tension, each of the spindles  11 ,  12  is also equipped with a spindle drive  11   d ,  12   d . A torque motor from Graham Motors and Controls™ of El Paso, Tex. is used for each of the drives  11   d ,  12   d . A torque motor uses a DC voltage and current from a DC drive circuit  11   c ,  12   c  (such as provided by Fincor Automation, Inc. of York, Pa.) to provide a torque output. The torque output varies from a maximum at zero rpm and diminishes as rpm increases. The maximum torque of both torque motors  11   d ,  12   d  may be adjusted to the same amount via a potentiometer  204 . The motor torque is used to accelerate the stationary roll of web material at a splicing event, and as the unwind spindle accelerates to a nominal running speed, the torque is reduced. The reduced torque at running speed results in little additional load for the brake to modulate, saving energy and reducing brake wear. The PLC  207  controller, acting according to an input from the splicing head  23  which will be described in more detail herebelow, activates or deactivates the drives  11   c ,  12   c  and motors  11   d ,  12   d  depending on which roll  11   a  or  12   a  is supplying the web  18 . 
     An air cylinder  205  may be used to provide additional tension in web  18 , for example when wider or thicker webs are fed through the device. The tension may be adjusted via an air regulator  206  which adjusts the air pressure provided to the air cylinder. 
     When a splice is required to join a depleting roll of web material to a replenishing roll of web material, the opposing, essentially mirror-image splicing heads  14 ,  15  perform a splicing operation. While the splicing operation may range from a manual initiation, to a fully automated operation, a manual operation will be described. 
     Referring now to  FIGS. 3   a - e , which illustrate sequential steps in a typical splicing operation, splicing heads  14  and  15  are illustrated in schematic format, omitting conventional structural components such as frames, bearings, connecting and operating links, etc., to show the operation of the inventive splicing process and apparatus. 
     In  FIG. 3   a , depleting web  318   a  supplies web to the accumulator  13  of  FIG. 1  and the web consuming machine. Web  318   a  is routed through the upper splicing head  14  via idler rollers  319 ,  323 . Replenishing web  318   b  is in a stationary, standby condition, nearly ready to splice to the depleting web  318   a . Splicing cylinders  314 ,  315  are also in a stationary, stand-by condition. An operator has manually prepared splicing station  15 . Access to splicing cylinder  315  is provided by door  319   d . In  FIG. 3   a  the lower door  319   d  is shown in the open position. It may be closed, by swinging it upwards in the direction of the arrow A after preparing the replenishing web  318   b  for a splicing operation. In comparison door  319   e  of splicing head  14  is shown in the closed position. To prepare splicing cylinder  315  for the next splicing operation, the operator applies a piece of adhesive tape  318   t  to the vacuum-equipped portion of splicing cylinder  315 . The vacuum (i.e. reduced pressure below atmospheric) is provided in a known method by a vacuum source (blower)  24  ( FIG. 1 ). Vacuum hose (not shown) connects the source  24  to a vacuum manifold fitted to at least one end of splicing cylinder  315 . The vacuum manifold provides vacuum to the gun-drilling  315   a  and vacuum holes  315   b  provide vacuum (suction) to the outer surface of the splicing cylinder  315 . The vacuum holds the adhesive tape  318   t  to the circumference on the splicing cylinder adjacent the vacuum holes  315   b . The vacuum equipped surface of cylinders  314 ,  315  may be provided with a neoprene surface with a nominal thickness of 0.030″ thick. The neoprene provides several benefits:
         It provides a visual cue to the operator for applying and locating the piece of tape  318   t;      It helps to seal the vacuum when tape  318   t  covers the vacuum holes  314   b ,  315   b ; and   It enhances the grip of the tape  318   t  on the cylinder  314  or  315 .       

     The operator then pulls the leading end of the replenishing web  318   b  around idlers  319   a  and adheres the lead edge of replenishing web  318   b  to the trailing half of the adhesive of the adhesive tape  318   t  (as illustrated). A vacuum plate  319   h  holds the web  318   b  so that when the operator closes the access door  319   d , a loop  318   c  is formed from the replenishing web  318   b  approximately as shown. The loop  318   c  ( FIG. 3   b ) provides an amount of slack web that will facilitate the splicing process, but otherwise the size of loop  318   c  is not especially critical. Vacuum may be supplied to the plate  319   h  from the vacuum blower  24  ( FIG. 1 ) via hose or piping (not shown). In the instant invention, a rotary union may be used at the door  319   d  pivot for a more compact and dependable solution than a hose which flexes and wears each time the door  319   d  is opened and closed. 
       FIG. 3   b  shows the apparatus in a standby condition, with access door  319   d  closed, where the apparatus is ready to splice web  318   b  to depleting web  318   a . Cylinder  314  is provided with opposing flats  314   f ,  315   f  which provide clearance for the web  318   a , in case its delivery should become unsteady and a ‘flutter’ or waving of web  318   a  occur. Further, the flats (on both cylinders  314  and  315 ) advantageously reduce the polar moment of inertia of splicing cylinders  314 ,  315 . Anvil strip  320  is in a stationary, standby position, as shown. An anvil strip  320  is driven in conjunction with the rotation of cylinders  314 ,  315  as shall be further disclosed herebelow. 
     Referring next to  FIG. 3   c , a splicing operation has been activated. The activation could occur in a variety of ways, for example: 
     1. In a fully automated process, where a sensor (not shown) has sensed that the supplying roll  11   a  ( FIG. 1 ) is nearly depleted and thus signal and initiate a powered rotation of splicing cylinders  314 ,  315 , 
     2. In a semi-automated process, where the operator has determined that supplying roll  11   a  is nearly depleted and pressed a button, or otherwise actuated the system to initiate a powered rotation of the splicing cylinders  314 , 315 , or, 
     3. In a manual process, where the operator has been signaled or observes that the supplying roll  11   a  is nearly depleted and initiates a rotation of the splicing cylinders  314 ,  315  via a crank handle or the like. The manual process illustrates the simplicity of the inventive splicing method because it demonstrates that no particular operator technique, timing, or speed coordination are required for a flying splice. This also suggests that other known methods of driving and automating the splicing operation may be readily applied. 
     Regardless of the method of rotating the splicing cylinders  314 ,  315 , splicing cylinder  314  counter-rotates relative to splicing cylinder  315  via 1:1 gearing that couples the cylinders, as will be disclosed in more detail herebelow. The directions of rotation of cylinders  314  and  315  are indicated by arrows in  FIGS. 3   c - 3   d  as is the web direction  318   a  or  b . Of course, alternative web directions could be accommodated by revising the cylinder rotations accordingly. As cylinders  314 ,  315  rotate, anvil  320  moves from its initial position as shown in  FIGS. 3   a  and  3   b  towards a position in between splicing cylinders  314 ,  315  to provide a cutting anvil surface for blade  314   g  as shown in progressive stages in  FIGS. 3   c  and  3   d . In  FIG. 3   e , anvil  320  has retracted to its initial or standby position. 
     Splicing cylinder  314  is equipped with a cutting blade  314   g  and a pad  314   h . Splicing cylinder  315  is equipped with a counterpart blade  315   g  and pad  315   h . The blades are cutting rule as provided by Helmold of Elk Grove Village, Ill. The pads are nominally ⅛″ thick Poron foam with a pressure-sensitive adhesive backing as provided by McMaster-Carr Supply Company of Elmhurst, Ill. In  FIG. 3   c , the pad  314   h  has rotated with cylinders  314  and  315  such that it is now contacting web  318   a  and pressing web  318   a  into contact with the surface of cylinder  315 . This contact has the effect of engaging the moving web  318   a  with the moving cylinder  315 , in the case of the manually operated system, this has the beneficial result of approximately, and automatically, matching the speed of the web  318   a  and the splicing cylinder  315  surface. The function of pad  314 H could alternatively be provided by other forms of protuberance such as a metallic or plastic leaf spring, or a blast of compressed air provided via drillings in cylinder  314  and air manifold as known in the art. It is advantageous for splicing cylinders  314 ,  315  to have a reasonably low rotational inertia, although the instant apparatus splices delicate webs as narrow as 2″ at production speeds with steel splicing cylinders approximately 15 in. wide and 4 in. in diameter. 
     Again referring to  FIG. 3   c , anvil  320  has advanced towards the nip between the cylinders  314 ,  315 , driven via a crank/connecting rod linkage, which is disclosed in more detail below. As seen in  FIG. 3   c , the lead edge of adhesive tape  318   t  is about to contact the bottom surface of web  318   a . The loop  318   c  of web material  318   b  has diminished to some extent, as the stationary web  318   b  approaches the speed of the depleting web  318   a.    
     A lobe  321  of cylinder  315  interacts with a proximity switch  322  which activates one of spindle drive torque motors  11   d  or  12   d  ( FIGS. 1 ,  2 ) to a preset torque. In  FIG. 3   c , the proximity of lobe  321  to proximity switch  322  will cause proximity switch to assume an ‘on’ or ‘high’ condition, which via a PLC (programmable logic controller)  207  ( FIG. 2 ) such as provided by Omron Manufacturing of America, St. Charles, Ill., activates the drive  11   c  to power torque motor  11   d  to a preset torque which tends to drive the web  318   a  as modulated by pneumatic brake  11   b  as described previously. 
       FIG. 3   d  shows the splicing mechanism after further rotation, at some point after tape  318   t  has adhered to the bottom surface of web  318   a  and effectively joined the lead edge of web  318   b  to web  318   a  and just as blade  321  has engaged web  318   a . The loop  318   c  has been taken up as the replenishing web  318   b  accelerates to the speed of the depleting web  318   a.    
     Lobe  321  is leaving proximity with proximity switch  322  causing a change in state of switch  322  from an ‘on’ or ‘high’ condition to an ‘off’ or ‘low’ condition. The change of state causes PLC  207  (of  FIG. 2 ) to switch off drive  11   c  and torque motor  11   d  and switch on drive  12   c  and torque motor  12   d . These actions tend to decelerate roll  11   a  and accelerate roll  12   a  at essentially the same time as blade  314   g  and anvil  320  cooperate to sever web  318   a.    
     Blade  314   g  is adjusted to a height sufficient to sever web  318   a  against anvil  320 , while web  318   b  travels below anvil  320  and so replenishing web  318   b  is not severed. The anvil  320  is supported during the severing action by the underlying web  318   b  and the surface of splicing cylinder  315 , and the anvil  320  is interposed between blade  314   g  and the replenishing web  318   b  to protect the replenishing web  318   b  from being cut. 
       FIG. 3   e  shows a further rotation of splicing cylinders  314  and  315 . Flats  314   i ,  315   i  are now adjacent and parallel the general path of web  318   b  between splicing cylinders  314 ,  315  as it travels to the accumulator  13  (of  FIG. 1 ). Anvil  320  is withdrawn to its inactive or rest position. The spliced portion, where tape  318   t  and replenishing web  318   b  are joined with depleting web  318   a , is illustrated downstream of roller  323 . A slight overlap of the webs  318   a ,  318   b  as shown is desirable, so that the aggressive adhesive of tape  318   t  is completely covered to prevent it from adhering to a roller or turn bar or the like as it travels to the web-consuming device. The presence of an overlap or a gap is largely a matter of the positioning of the lead edge of web  318   b  as it is placed onto the tape  318   t  in the set-up step of  FIG. 3   a . Scribe marks on the surface of cylinders  314 ,  315  or other visual aids to the operator assist in assuring the desired overlap condition. The anvil  320  has retracted to its initial position as in  FIG. 3   a, b . Roll  11   a  will ideally have stopped rotating to avoid feeding out excessive amounts of web  318   a . It should be noted that the exact stopping instant of roll  11   a  is not critical to the satisfactory function of the splicer. The operator may now remove depleted roll  11   a  of  FIG. 1  and replace it with a full roll on spindle  11 . Vacuum holes  314   b  are now positioned so that when the operator opens the door  319   e  in the direction of the arrow, thus moving idler rollers  319  out of the way, the operator may prepare another piece of tape, setting it over the vacuum holes  314   b . The lead end of the web  318   a , from the replaced, full roll  11   a  ( FIG. 1 ) may be attached to the tape, again providing a loop of web material  318   a , similar to the counterpart, loop  318   c , previously prepared in web  318   b . This prepares the splicer for the next splice, i.e., when web  318   b  later becomes depleted and another splice cycle may be initiated using the mirror-image counterparts of the components described in  FIGS. 3   b, c, d  and as described above. 
     In a manually controlled splicer, detents may be provided to assist the operator in positioning the splicer in either of the standby positions, as shown in  FIGS. 3   a, b , and  e . It is particularly desirable that the operator not over-rotate the splicing mechanism because if the splicing cylinders  314 ,  315  are rotated too far before beginning a splice, one of the blades  314   g  or  315   g  may unintentionally sever the supplying web before another splice is prepared, resulting in the need to stop the web consuming machine and re-web the splicer and web consuming machine, a time-consuming process. In an automatic or semi-automatic splicer, a conventional servo drive or equivalent may be readily programmed to position the rotors in the standby positions  3   a, b  and  3   e . Such a servo drive, e.g., Indradrive provided Bosch Rexroth with US headquarters in Hoffman Estates, Ill. may also be programmed to rotate the splicing cylinders at appropriate speeds to match, approximately or precisely, the speed of the active, i.e., depleting web, allowing rapid splices at high web speeds with minimal variation in web tension. The servo drives can also readily be programmed to include interlocks so that servos will not rotate splicing cylinders  314 ,  315  and will not move anvil  320  unless the doors  319   d ,  319   e  are closed, said doors also including guards to prevent human access into the splicing cylinders&#39;  314 ,  315  in-running nip. 
     Idler roller  323  may be equipped with a speed and direction of rotation sensor which may interact with PLC  207  and drives  11   c ,  12   c  to monitor feeding of the web (either  318   a  or  318   b ). For example, if idler  323  is not rotating when either of drives  11   c  or  12   c  are activated, this is an indication that the web is not flowing properly through the apparatus and drives  11   c  and  12   c  should be turned off to prevent uncontrolled unwinding of roll  11   a  or  12   a . Similarly, if idler  323  rotates backwards, this would be an indication of a “wrap-up” of web in some part of the splicing apparatus and again drives  11   c  and  12   c  should be turned off and an alarm may be sounded and/or lit. 
     In case of a splicing event while the supplying web is stopped, and simultaneously carriage  17  ( FIGS. 1 ,  2 ) is near the bottom of its travel and thus activating the brakes  11   b ,  12   b , it would be beneficial to release the brakes  11   b ,  12   b  momentarily to allow the supplying web to move as it is gripped by splicing cylinders  314 , 315  as in  FIGS. 3   c , 3   d . The speed sensor associated with idler  323  would supply a zero speed signal to PLC  207  ( FIG. 2 ) which would be programmed to process this zero speed signal and the near-bottom position signal of carriage  17  (via encoder  202 ) and then deliver a command to release the brakes  11   b ,  12   b  during the splicing operation. The splicing operation could be signaled to the PLC  207  in a variety of ways:
         The operator could press a button during a splice.   A sensor could be mounted to read the motion of gear teeth  424 ,  414   j , or  415   j  as shown in  FIG. 4   a.      A proximity switch could be mounted near the periphery of one of the cylinders  314 ,  315 —in running position (no splice) the switch would be positioned to sense the position of any of the flats  314   f, i  or  315   f, i  and to signal a splice, the proximity switch  322  would become active when the non-flat periphery of splicing cylinders  314 ,  315  approaches the proximity switch.   An encoder could be installed on the rotational axis of either splice cylinder or drive gear  424  to provide speed and/or position data to the PLC  207 .
 
A simpler alternative to accommodating a splice while the web  318  is stopped is to build-in some compliance or over-travel to a portion of the web guiding idler roller upstream (preceding) the splicing head  23 , such as in the doors  319   d, e . The doors  319   d, e  could allow some over travel under a greater than operating load, to allow the doors to deflect as needed to allow the stationary depleting web to move as required when it is engaged by one of the pads  314   h ,  315   h  and the opposing cylinder  315 , 314 , respectively, then when the splice is completed, the doors  319   d,e  would be free to spring back into their normal closed position.
       

       FIG. 4   a  is a schematic end view of the splicing assembly  23  of FIG. without conventional frames, bearings, etc., that support and allow rotation of cylinders, etc.  FIG. 4   b  is a simplified schematic side view of a portion of splicing assembly  23 .  FIG. 4   b  also deletes conventional frames, bearings, guides, etc., that locate and support the various components of the invention.  FIGS. 4   a, b  illustrate the mechanism coordinating the rotation of splicing cylinders  314  and  315  as well as the motion of anvil  320 . Each of cylinders  314 ,  315  is equipped with a timing gear  414   j  and  415   j  respectively. In  FIG. 4   b , gears  414   j ,  415   j  are shown towards respective ends of the splicing cylinder  315 . These gears provide symmetrical driving for both ends of the anvil strip  320 , as the length of the anvil strip  320  typically precludes the use of a cantilvered or centered drive. Gears  414   j  and  415   j  could advantageously have a circular pitch so the pitchline of the gear coincides with the effective diameter of the splicing cylinder. This allows the gears to act directly on each other and eliminates the need for idler gears. In the illustrated embodiment, the splicing cylinders  314 ,  315  are the same diameter and so the gear ratio between gears  414   j  and  415   j  is 1:1. Other (non-matching) diameters and ratios could be employed as well. In the instant invention, drive gear  424  is activated by a human operator via a crank handle  425 . Drive gear  424  ( FIG. 4   a ) includes a hub  434  with crankpin  426 . Crank pin  426  drives a connecting rod  427  which drives anvil strip  320  via a slide block  428  which is guided by a guide rod  429 . Slide block  428  includes a secondary guide bar  430 , a cushion spring  431  and an anvil slide block  432 . Anvil slide block  432  includes a mounting pin  433  to anchor on the near side of the anvil  320  on the anvil slide block  432 . Drive gear  424  has half the number of teeth as drive gear  414   j  because the anvil strip is to cycle twice for every revolution of the splicing cylinders, i.e., there are two splicing cycles for one revolution of handle  425  in the illustrated embodiment. 
     The timing of the positioning of the anvil strip  320  relative to position of the cutting blade  314   g  is preferrably adjusted so that the anvil strip leading edge  320   a  clears the foam pad  314   h  (see  FIGS. 3   c , d) and also the insertion speed of the anvil strip approximately matches the speed of the tip of blade  314   g ,  315   g  during a web severing event. The timing may be adjusted by known means of shifting the phase of gear  424  on a hub  434 . The hub  434  includes the crankpin  426 . For the geometry of  FIG. 4 , when the crankpin  426  is at the 12 o&#39;clock position, the lead edge  320   a  of the anvil  320  will be slightly past the blade  314   g  and the speed of the anvil  320  will match the peripheral speed of the tip of blade  314   g.    
       FIG. 4  is schematic in nature, therefore the instant invention, which may have splicing cylinders  314 ,  315  and anvil strip  320  approximately 14½ inches wide, has components  428 ,  429 ,  430 ,  431 ,  432  and  433  at each end of the anvil strip, to properly support it, even though only one end is shown. 
     Several alternative embodiments are envisioned with the goal of reducing or even eliminating the need for a vacuum system; a vacuum system increases the initial cost of the apparatus and the operating costs. 
     In an embodiment which eliminates the need for vacuum at the splicing cylinders  314 ,  315 , a splicing tape with adhesive on both sides could be substituted for the one-side adhesive tape  318   t  of  FIG. 3   a . The adhesive on a first side would hold the tape  318   t  to the splicing cylinder  315 , the adhesive on the second side would adhere the tape to the lead end of replenishing web  318   b . Preferably, the adhesive tape would have a relatively weaker adhesion to the surface of the splicing cylinder  315 , so that it would not interfere with the eventual transfer from the splicing cylinder  315 , during the splicing operation, to the depleting web  318   a . This would eliminate the need for vacuum provisions in the splicing cylinders  314 ,  315  and the attending costs of vacuum drilling  315   a  and vacuum holes  315   b  (and their counterparts in cylinder  314 ), the vacuum manifold, not shown, and attending hoses and piping. The need for vacuum at the vacuum plates  319   h ,  319   i  in doors  319   d ,  319   e  could be supplied by a smaller vacuum blower  24 . Or, the blower  24  could be eliminated entirely by using conventional pneumatic clamps instead of the vacuum plates  319   h ,  319   i . Such clamps would be released during the splicing sequence via the controller and solenoid valves. 
       FIGS. 5   a - e  and  6  illustrate an alternative embodiment of splicing head  23  and method for holding the lead end of a replenishing web  318   b  and providing a simplified mounting and driving of anvil strip  320 . Splicing cylinder  315  is equipped with magnets  510  (one illustrated in schematic end view  FIG. 5   a - e , see  FIG. 6  for side view) and lugs  511  (again only one shown in schematic  FIG. 5   a - e , but spaced along the length of the cylinder, see  FIG. 6  for side view). The operator places tape  318   t  on the surface of the cylinder  315 . The operator then places the lead edge of replenishing web  318   b  on trailing half of tape  318   t  on cylinder  315 . In  FIG. 6  the lead portion of tape  318   t  is shown; the trailing portion of tape  318   t  lags behind and is adhered to web  318   b . Next, the operator places anvil strip  320  over the lead end of web  318   b , abutted against end lugs (one shown but spaced across the axial length of the cylinder)  511 . The anvil strip  320  is preferrably made of a ferrous steel alloy, so the magnets  510  hold the anvil strip  320  in place on the splicing cylinder  315  and, in turn, the lead end of web  318   b  is clamped in place between anvil strip  320  and surface of cylinder  315 . A raised resilient strip  512  may be placed on both sides of the anvil strip  320 ; the raised strip on the left side of anvil strip  320  assures the flat anvil strip  320  has its lead edge firmly clamping tape  318   t  and web  318   b  against the splicing cylinder  315  surface, as shown, to cooperate properly with blade  314   g  during the cutting operation of supplying web  318   a . The resilient strip  512  protrudes from both sides of anvil strip  320  so that its lead edge may be tipped into contact with either of the splicing cylinders  314  (when supplying web is  318   b ) and  315  (when supplying web is  318   a ) as required. Vacuum may be provided, as described previously, to vacuum holes ( 315   b  for cylinder  315 ) to hold the leading portion of tape  318   t  on the surface of splicing cylinder  315 , as opposed to having tape  318   t  curl upwards or flap loose during rotation. Vacuum may be provided continuously, or intermittently, i.e., during a splicing operation, to save energy by running a vacuum source only when needed. Lanyards  513  hook onto anvil  320  via a hole at each end of the anvil strip and hooks  513   e . Lanyard  513  is tensioned via a retractor assembly  514 . When a splice is initiated, the cylinders  314  and  315  rotate in cooperation as described previously ( FIGS. 3   b - e ). 
     Referring to  FIG. 5   b , a splice has been initiated and pad  314   h  presses the adhesive-equipped tape onto web  318   a . Anvil strip  320  rotates along with cylinder  315 , while the retractor  514  pulls in lanyard cable  513  to prevent slack in lanyard  513 . End caps  515  ( FIG. 6 ) may be equipped with grooves to locate and guide the lanyards  513 . 
     In  FIG. 5   c , further rotation of splicing cylinders  314  and  315  has occurred. Blade  314   g  severs the depleting web  318   a  against the anvil  320 . As in previous embodiments, anvil  320  overrides and prevents the replenishing web  318   b  from being cut, i.e., web  318   a  is on the upper surface of anvil  320  and web  318   b  is beneath anvil strip  320 . Retractor assemblies  514  retract some of lanyards  513  and prevent slack from developing in lanyards  513 . 
     In  FIG. 5   d , web  318   b  is now the supplying web (and will become the depleting web) and web  318   a  is severed and slack. Anvil  320  is now retained by the lanyards  513  and the lanyard hook  513   e  is bottomed in the end  514   e  of the retractor assemblies  514 . 
     In  FIG. 5   e , the spliced portion of the web has proceeded past the splicing cylinders  314 ,  315 , as seen in the drawing, the splicing tape  318   t  joins the severed end of depleting web  318   a  to the lead end of the replenishing web  318   b . The retractor assemblies  514  and lanyards  513  have pulled anvil  320  to a retracted position and clear of the splicing cylinders  314 ,  315 , with the flats on the splicing cylinders providing additional clearance for the web and the anvil strip  320 . Handles  320   h  provide a convenient way for an operator to pull the anvil strip  320  out, so it is accessible for setting up the next splice, this time with a piece of tape on the upper splicing cylinder  314 , so that web  319   a  may be prepared for the next splice. Splicing cylinder  314  is equipped with magnets, lugs etc. as described above for splicing cylinder  315 . In this way, continuous supply of web to a web consuming device is possible by alternately reloading spindles  11 ,  12  ( FIG. 1 ) and splicing cylinders  314 ,  315 . 
     As in  FIGS. 3   a - e , the mirror-image arrangement of splicing apparatus  23  in  FIG. 5  has splicing cylinders  314 ,  315  both equipped with blades, pads, etc. to allow the splicing operation to be initiated from the lower cylinder  315  and lower spindle  12  ( FIGS. 1 ,  2 ) as described above, then be initiated from the upper cylinder  314  and upper spindle  11  and so on. 
     Having thus disclosed in detail plural embodiments of the invention, persons skilled in the art will be able to modify the structure illustrated and substitute equivalent elements for those disclosed; and it is, therefore, intended that all such substitutions and equivalents be covered as they are embraced within the scope of the appended claims.