Abstract:
An apparatus for transporting and weighing articles while in motion including a base structure and a driving mechanism, connected to the base, for contacting an article along a first surface and transporting the article along a transport path. A vertical support baffle, connected to the base, is configured to contact the article along a second surface and guide said article along the transport path. A weighing mechanism is connected to the base, and the driving mechanism is configured to calculate the weight of the article as it is moved along the transport path. The present invention also includes a method for moving and weighing articles including the steps of moving the article along a transport such that the transport is coupled to weighing mechanisms. The weight of the article is then measured.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention disclosed herein relates generally to automated mail sorting and more particularly, an apparatus and method for weighing mail in motion, or on the fly, while maintaining the mail in a vertical orientation.  
         BACKGROUND  
         [0002]    The processing and handling of mailpieces consumes an enormous amount of human and financial resources, particularly if done manually. In addition to the postal service, the processing and handling of mailpieces occurs at each and every business or site where communication via the mail delivery system is utilized. Various pieces of mail generated by multiple departments and individuals within a company need to be collected, sorted, addressed and franked as part of the outgoing mail process. Additionally, incoming mail needs to be collected and sorted efficiently to ensure that it gets to the addressee in a minimal amount of time. Since much of the mail being conveyed through the mail system is critical in nature, it is imperative that the processing and handling of both the incoming and outgoing mailpieces be efficient and reliable so as not to impact negatively the operation of the business.  
           [0003]    In view of the above, various automated mail handling machines have been developed for processing mail (removing individual pieces of mail from a stack and performing subsequent actions on each individual piece of mail). However, in order for these automatic mailing machines to be effective, they must process and handle “mixed mail”. The term “mixed mail” is used herein to mean sets of intermixed mailpieces of varying size (postcards to 9″ by 12″ flats), thickness, and weight. In addition, the term “mixed mail” also includes stepped mail (i.e., an envelope containing an insert which is smaller than the envelope to create a step in the envelope), tabbed and untabbed mail products, and mailpieces made from different substrates. Thus, the range of types and sizes of mailpieces which must be processed is extremely broad and often requires trade-offs to be made in the design of mixed mail feeding devices in order to permit effective and reliable processing of a wide variety of mixed mailpieces.  
           [0004]    In known mixed mail handling machines which separate and transport individual pieces of mail away from a stack of mixed mail, the stack of mixed mail is first loaded onto some type of transport system for subsequent sorting into individual pieces of mail. Typically, it is preferable to transport a mailpiece in a vertical orientation (on its bottom edge) in order to facilitate the manipulation of individual mailpieces. In systems handling outgoing mail, it is necessary to affix the individual mailpieces with the proper postage. To calculate proper postage it is necessary for the system to determine the distance and manner in which a mailpiece is being sent in addition to its size and weight.  
           [0005]    Various scanning and sorting technologies have been implemented as part of automated mail handling systems to determine the distance and manner in which a mailpiece is being sent along with its size. However, prior art systems of mail handling do not adequately provide for the accurate calculation of the weight of a particular mailpiece as it is being processed. To weigh a mailpiece as quickly and accurately as possible, it is desirable to minimize the amount of vibration while weighing the mailpiece. The method used in numerous contemporary systems is to stop the transport of the mailpiece during weighing. While this reduces the vibration caused by the transport, it also increases the cycle time of the mailpiece due to the time required to decelerate the mailpiece, wait for the transport to settle, measure the weight of the mailpiece and accelerate the mailpiece out of the system. Still other contemporary mail handling systems require that the weighing process be performed on a horizontally oriented mailpiece.  
           [0006]    Although weighing mailpieces while in transport reduces the need for stopping the system, certain situations require the mail process to be halted. For example, if the weight of the mailpiece is very close to the postal weight break, the accuracy needed to prevent an inaccurate weight classification may require more time and scale stability than can be provided a moving transport. In such a case, there are three choices: 1) apply postage that may be incorrect, 2) acknowledge the incorrectly weighed mailpiece and divert it away from the stack of mail, or 3) stop the transport and wait for the scale to stabilize and then reweigh the mailpiece. The present invention provides for the third scenario, i.e., stop-on-demand weighing. For example, first class letter rates increase by the ounce. Thus, the postal weight breaks are at one ounce, two ounces, three ounces and so forth. When the system weighs a mailpiece, if the postal weight break is within the weight of the mailpiece plus or minus the weighing system&#39;s margin of error, the mailpiece is reweighed. This feature allows the system to automatically stop when more precise measurements are needed.  
           [0007]    One of the problems of the prior art is that an apparatus is not available for the accurate calculation of the weight of a mailpiece while the mailpiece is in a vertical orientation, that is, on a mailpiece&#39;s bottom edge. Another problem of the prior art is that mechanical vibrations introduced by the system generate inaccurate weight measurements. Yet another problem of the prior art is that the weighing process requires the re-orientation of the mailpiece to be weighed or a stoppage in the mail handling process in order to generate an accurate weight measurement. Therefore, a method is needed to provide for the efficient measurement of the weight of a mailpiece while maintaining the vertical orientation of the mailpiece.  
         SUMMARY OF THE INVENTION  
         [0008]    Utilized as part of a complete system of automated mail handling, the present invention overcomes the disadvantages of the prior art by providing an apparatus and method for accurately measuring the weight of vertically oriented mailpieces without stopping the mail handling process. In a currently preferred embodiment of the invention, a bottom belt transport oriented parallel to the base and with vertical baffles is mounted on a weighing mechanism (load cell) which in turn is mounted on the base of the apparatus. In this configuration, mailpieces enter the transport in a vertical orientation and are biased against the bottom of the belt by gravity. This eliminates the need for ski rollers, which create vibrations, as they engage and disengage the mailpieces. Only two rotating elements are required in this transport, which also reduces vibration. By minimizing vibration, a measurement of the weight of the mailpieces can be determined more accurately and quickly, thereby increasing overall throughput of the apparatus.  
           [0009]    In another currently preferred embodiment, a bottom belt transport, also oriented parallel to the base, is mounted on a pair of load cells which, in turn, are independently mounted to the base of the apparatus. Again, mailpieces enter the transport in a vertical orientation and are biased against the bottom of the belt by gravity. A first load cell is located at the input end of the apparatus, and a second load cell is located at the output end of the apparatus. The signals received from the first and second load cells are combined via a trim balance circuit which, in turn, transmits the weight to the main processing system of the mail handling system in which the inventive apparatus is installed.  
           [0010]    In yet another preferred embodiment, the vertical baffles are held in place by baffle support brackets which, in turn, are mounted directly to the base of the apparatus. Isolating the baffles from the transport and load cells reduces vibration at the load cells by limiting the vibration caused by mailpieces impacting the baffles. By minimizing vibration, a measurement of the weight of the mailpieces can be determined more accurately and quickly, thereby increasing overall throughput of the apparatus. Vertical baffles held in place by baffle support brackets may be utilized in apparatus using either one or a plurality of load cells to measure the weight of the mailpiece in the transport.  
           [0011]    In yet another preferred embodiment, the transport belts are oriented perpendicular to the base. The entire system is mounted on top of a structural pillar connected to the base, thus making the entire system suspended in air. A single load cell has its weighing surface oriented parallel to the transport belts, or perpendicular to the base. Any vibrations or oscillations in the mechanics of the system would be minimized because they would not occur in the same vector as the weight of the mailpiece.  
           [0012]    Thus, an advantage of the present invention is that it may accurately weigh mailpieces in a vertical orientation, or on their bottom edge. Another advantage is that the present invention reduces the overall vibration present in the system, thereby providing a more accurate calculation of weight. Yet another advantage of the present invention is that it does not require the transport to be stopped in order to calculate the weight of a mailpiece.  
           [0013]    Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aforementioned advantages are illustrative of the advantages of the various embodiments of the present invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, and together with the general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention.  
         [0015]    [0015]FIG. 1 is an isometric view of a dual load cell embodiment of the mail handling apparatus with a horizontal mail weighing transport of the present invention;  
         [0016]    [0016]FIG. 2 is a side view of the mail handling apparatus illustrated in FIG. 1;  
         [0017]    [0017]FIG. 3 is an end view of the mail handling apparatus illustrated in FIG. 1;  
         [0018]    [0018]FIG. 4 is a cross sectional end view of the mail handling apparatus illustrated in FIG. 1;  
         [0019]    [0019]FIG. 5 is a circuit diagram of a trim balance circuit for use in a dual load cell embodiment of the mail handling apparatus of the present invention;  
         [0020]    [0020]FIG. 6 is an isometric view of a single load cell embodiment of the mail handling apparatus of the present invention with a horizontal mail weighing transport;  
         [0021]    [0021]FIG. 7 is a side view of the mail handling apparatus illustrated in FIG. 6;  
         [0022]    [0022]FIG. 8 is a front view of a single load cell embodiment of the mail handling apparatus of the present invention with a vertical mail weighing transport; and  
         [0023]    [0023]FIG. 9 is a rear view of a single load cell embodiment of the mail handling apparatus illustrated in FIG. 8;  
         [0024]    [0024]FIG. 10 is a flow diagram of the stop on demand weighing process. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Horizontal Mailpiece Weighing Transport with Dual Load Cells  
         [0026]    Referring to FIGS. 1, 2,  3  and  4 , a mailpiece weighing transport  102  is shown. Mailpiece weighing transport  102 , as will be discussed in more detail below, weighs and transports an individual mailpiece  104  along transport belt  106  from the input end of mailpiece weighing transport  102 , generally designated by arrow  108   a  to the output end of mailpiece weighing transport  102 , generally designated by arrow  108   b . The course that the mailpiece  104  travels from the input end  108   a  to  108   b  is the transport path.  
         [0027]    Mailpiece weighing transport  102  includes a base  110  upon which all of the components of mailpiece weighing transport  102  are mounted. In one preferred embodiment, a pair of load cells  112   a  and  112   b  are used to measure the weight of mailpiece  104  as it travels through mailpiece weighing transport  102 . Load cell  112   b  is mounted on base  110  at input end  108   b  and load cell  112   a  is mounted on base  110  at output end  108   a . Load cell support brackets  114   a  and  114   b  connect load cells  112   a  and  112   b  to support plate  120 . Any type of forward driving mechanism can be used to transport mailpiece  104 . Preferably, the forward driving mechanism comprises a transport belt  106 . Transport belt  106  is attached to support plate  120  by drive pulley  116  and idler pulley  118  and is supported by slider plate  122  which is also attached to support plate  120 . Locomotion to the system is provided by motor  130  which is mounted on mailpiece weighing transport  102  and directly connected to drive pulley  116 . Along the transport path are guides that ensure the mailpiece  104  stays on the transport path. Support baffles  124   a  and  124   b , examples of guides, are mounted parallel to each other on opposing sides of transport belt  106 . Support baffle  124   a  is held in place by support baffle brackets  126   a ,  126   b  and  126   c  which are mounted on base  110 . Support baffle  124   b  is held in place by support baffle brackets  126   d ,  126   e and  126   f which are mounted on base  110 .  
         [0028]    In general, the present invention determines the weight of a mailpiece  104  by measuring the load generated (the signal output by the load cells  112   a  and  112   b  combined) by a mailpiece  104  combined with the weighing platform (the components of mailpiece weighing transport  102  which are mounted on top of the load cells  112   a  and  112   b ), then subtracting the known load generated by the weighing platform (the tare). The remaining load is assumed to be generated by mailpiece  104  and any transient vibrations caused by the system and/or movement of mailpiece  104 . The measurement of the load minus the tare is then filtered to account for any transient vibrations, and the resulting measurement is then converted to a weight measurement and transmitted to mail processing system controller  100  (such as the WOW board utilized in Pitney Bowes Paragon® and Galaxy® automated mail processing systems). In a multiple load cell configuration, the measurements from each of the load cells  112   a  and  112   b  are combined using a trim balance circuit  128  before the measurement is transmitted for further processing to determine the weight of mailpiece  104 .  
         [0029]    In operation, a mailpiece  104  enters the mailpiece weighing transport  102  in a vertical orientation at input end  108   a  and travels along on transport belt  106  towards output end  108   b . Mailpiece  104  is biased against transport belt  106  by a normal force, gravity, and is maintained in a vertical orientation by support baffles  124   a  and  124   b  that prop up the side surface of the mailpiece  104 . Support baffles  124   a  and  124   b  prevent mailpiece  104  from toppling over as it is moved through mailpiece weighing transport  102 . The weighing platform of mailpiece weighing transport  102  consists of transport belt  106  (an endless flat belt) supported between drive pulley  116  and idler pulley  118  with slider plate  122  which are mounted together to support plate  120 . Forward motion is provided to transport belt  106  by motor  130  which is mounted on support plate  120  and directly connected to drive pulley  116 .  
         [0030]    As mailpiece  104  moves along transport belt  106 , it causes load cells  112   a  and  112   b  to generate electrical analog output signals proportional to the force being applied to the top surface of the load cells  112   a  and  112   b  in response to the force of gravity acting upon the weighing platform and the mailpiece  104 . The electrical signals from  112   a  and  112   b  can be combined into a single signal via any appropriate signal converter known in the art. For example, the electrical signal can be combined via a trim balance circuit  128  and then transmitted to mail processing controller  100 .  
         [0031]    [0031]FIG. 5 is an illustration of the trim balance circuit  128 . The trim balance circuit is an example of a circuit that can be used in the mailpiece processing system. Any type of circuit that can combine the two input signals from the dual load cells  112   a  and  112   b  into a single output signal is appropriate for the system. The first connector  500  has eight terminals which represent +15 voltage DC power supply, positive side of the first signal from load cell  112   a , negative side of the first signal from load cell  112   b , ground, −15 voltage DC power supply, positive side of the second signal from load cell  112   b , negative side of the second signal from load cell  112   b  and ground. At nodes  502  and  504  are variable resistors R 1  and R 2  that can have a maximum resistance of about twenty ohms each. Between nodes  506  and  508  are two capacitors C 1 , C 2  in parallel. The second connector  510  has four terminals which represent +15 voltage DC power supply, positive side of output signal that proceeds to the mail processing controller  100 , negative side of output signal that also proceeds to the mail processing controller  100 , and ground.  
         [0032]    Referring again to FIGS. 1 through 4, support baffles  124   a  and  124   b , which prevent mailpiece  104  from toppling over as it is conveyed through mailpiece weighing transport  102 , are mounted on support baffle brackets  126   a ,  126   b ,  126   c ,  126   d ,  126   e , and  126   f  which are mounted to base  110 . Connecting the support baffles  124   a  and  124   b  in a vertical orientation to base  110  via on support baffle brackets  126   a ,  126   b ,  126   c , and  126   d ,  126   e ,  126   f  reduces transient vibration at load cells  112   a  and  112   b  by isolating vibrations caused by mailpiece  104  impacting support baffles  124   a  and  124   b . This arrangement also reduces the weight being carried by the load cells, in particular this configuration reduces the tare weight, thereby resulting in a more sensitive measurement of the load generated by mailpiece  104 .  
         [0033]    Horizontal Mailpiece Weighing Transport with a Single Load Cell  
         [0034]    Referring to FIGS. 6 and 7, a single load cell mailpiece weighing transport  640  is shown. Mailpiece weighing transport  640 , as will be discussed in more detail below, weighs and moves an individual mailpiece  641  along transport belt  642  from the input end of mailpiece weighing transport  640 , generally designated by arrow  644   a  to the output end of mailpiece weighing transport  640 . The course that the mailpiece  641  travels from the input end  644   a  to  644   b  is the transport path.  
         [0035]    Mailpiece weighing transport  640  includes a base  646  upon which all of the components of mailpiece weighing transport  640  are mounted. In one preferred embodiment, a single load cell  648  having a weighing surface  649  is used to measure the weight of a mailpiece  641  as it travels through mailpiece weighing transport  640 . Load cell  648  is mounted on base  646  at the center of gravity of mailpiece weighing transport  640 . Transport belt  642  is supported by drive pulley  652  and idler pulley  654  which, in turn, are connected to support plate  651 . Transport belt  642  is also supported by slider plate  650  which is also connected to support plate  651 . Locomotion to the system is provided by motor  630  which is mounted on mailpiece weighing transport  640  and directly connected to drive pulley  652 . Support baffles  656   a  and  656   b  are mounted parallel to each other and in a vertical orientation on opposing sides of transport belt  642 . Support baffle  656   a  is held in place by support baffle brackets  658   a ,  658   b  and  658   c  which are mounted on slider plate  650 . Support baffle  656   b  is held in place by support baffle brackets  658   d ,  658   e  and  658   f  which are mounted to the support plate  651 .  
         [0036]    In general, the single load cell embodiment of the invention functions the same as the dual load cell embodiment. The single load cell embodiment illustrated herein has the vertical support baffles integrated into the weighing platform as opposed to being attached to the base as illustrated in the dual load cell configuration. It will be understood by one skilled in the art that single and multiple load cell configurations may be provided with either base attached support baffles or weighing platform attached support baffles. It will also be understood that the single load cell embodiment does not require the use of a trim balance circuit to combine the load measurement prior to weight calculation. Just as with the dual load cell embodiment, the measurement of the load minus the tare is filtered to account for any transient vibrations and the resulting measurement is then converted to a weight measurement and transmitted to mail processing system controller  100  (such as the WOW board utilized in Pitney Bowes Paragon® and Galaxy® automated mail processing systems).  
         [0037]    In operation, a mailpiece enters the mailpiece weighing transport  640  in a vertical orientation at input end  644   a  and moves along on transport belt  642  towards output end  644   b . The mailpiece is biased against transport belt  642  by gravity and is maintained in a vertical orientation by support baffles  656   a  and  656   b  which prevent the mailpiece from toppling over as it is conveyed thorough mailpiece weighing transport  640 . The weighing platform of mailpiece weighing transport  640  consists of transport belt  642  (an endless flat belt) supported between drive pulley  652  and idler pulley  654  with slider plate  650  which are together mounted to support plate  651 , wherein forward motion is provided to transport belt  642  by motor which is mounted also on support plate  651  and directly connected to drive pulley  652 , and support baffles  656   a  and  656   b  are also part of the weighing platform.  
         [0038]    Vertical Mailpiece Weighing Transport  
         [0039]    The embodiments in FIGS. 1 through 7 feature a mail processing system with a mail weighing transport  102 ,  640  that is horizontal (parallel) to the base  110 ,  646 . In an alternative embodiment, the mail weighing transport can be constructed such that it is vertical (perpendicular) to the base.  
         [0040]    Referring to FIGS. 8 and 9, a vertical mailpiece weighing transport  802  is shown. Mailpiece weighing transport  802  weighs and transports an individual mailpiece  804  along the transport path from the input end of the mailpiece weighing transport  802 , generally designated by arrow  808   a  to the output end of the mailpiece weighing transport  802 , generally designated by arrow  808   b.    
         [0041]    Mailpiece weighing transport  802  includes base  810  upon which all of the components of mailpiece weighing transport  802  are mounted. Structural pillar  812  has a top surface  814  and a back surface  816 . Structural pillar  812  is connected to base  810  and is responsible for suspending all of the components of the mailpiece weighing transport  802 . Single load cell  818  has a weighing surface  820  and is located on the top surface  814  of the structural pillar  812 .  
         [0042]    Support plate  822  is a structure that holds all of the components of the mailpiece weighing transport  802  with the exception of base  810 , structural pillar  812 , and single load cell  818 . Support plate  822  has a front side  824 , back side  826 , input side  828 , output side  830 , and bottom edge  831 . The center of back side  826  of support plate  822  is connected to the center of the weighing surface  820  of single load cell  818 . Since single load cell  818  is connected to the center of the back side  826  of the support plate  822 , single load cell  818  is located at the center of gravity of the support plate  822  and the mailpiece weighing transport  802 . A drive pulley  832  and an idler pulley  834  are connected to the output side  830  and input side  828  of support plate  822 , respectively. A plurality of transport belts  836  having a front side  838  and back side  826  are connected to support plate  822  by drive pulley  832  and idler pulley  834  (both pulleys are depicted by phantom lines in FIG. 9). Both the front side  838  and back side  840  of the plurality of transport belts  836  reside in planes that are perpendicular to base  810 . Suspended pillar  842  having a front side  846  and back side  848 , is mounted to back side  840  of support plate  822 . A motor  850  is electrically connected to the drive pulley  832  and physically connected to the back side  848  of suspended pillar  842 . Transport guide  852 , having mounting points P 1  and P 2 , is mounted to bottom edge  831  of support plate  822 . Transport guide  852  is parallel to base  810  and runs the entire length of bottom edge  831  of support plate  822 . Holding brackets  854 ,  856  are mounted to mounting points P 1  and P 2  by C-clamps  858 ,  860 . Alternatively, the C-clamps  858 ,  860  can be eliminated, and the holding brackets  854 ,  856  can be directly mounted to transport guide  852 . Mounted to holding brackets  854 ,  856  are flat springs  862 ,  864 . A first sensor  866  is connected to the base on the input side. A second sensor  868  is connected to the base on the output side. Any type of sensor that can detect the movement of a mailpiece in the mail weighing system can be used. For example, optical sensors are able to perform this function.  
         [0043]    A mailpiece  804  in a vertical orientation enters the vertical mail weighing transport  802  at the input end  808   b . Mailpiece  804  is initially biased against front side  838  of transport belts  836 . As the mailpiece  804  moves along the mail weighing system  802 , the bottom edge of the mailpiece is in contact with transport guide  852 . The mailpiece  804  is kept in contact with front side  838  of transport belts  836  by the normal force created by flat springs  858 ,  860 . In this vertical mail weighing system  802 , the weighing platform comprises all of the components attached to single load cell  818 , that is support plate  822 , pulleys  832 ,  834 , transport belts  836 , holding brackets  854 ,  856 , C-clamps  858 ,  860 , flat springs  862 ,  864 , transport guide  852 , suspended pillar  842 , and motor  850 . The entire weighing platform constitutes the tare. The weight of mailpiece  804  is determined by measuring the load generated (the signal output by single load cell  818 ) when the mailpiece  804  pushes against the weighing surface  820  of the single load cell  818  minus the tare. As with the previous embodiments, the remaining load is assumed to be generated by mailpiece  804 , and the signal produced by single load cell  818  is converted to a weight measurement and transmitted to mail processing system controller  100 .  
         [0044]    The advantage of the vertical configuration of the mail weighing transport  802  is that it minimizes the introduction of vibrations or oscillations as noise into the weighing system. For example, pulleys  832 ,  834  and transport belts  836  have the potential to produce vibration which would impact the weighing process. By having the weighing surface of the load cell oriented vertically, any vibrations caused by pulleys  832 ,  834  and transport belts  836  are further minimized since some of the vibrations are divided between vertical and horizontal vectors. In contrast, the entire vibration would be experienced by the load cells in a horizontal mail processing system.  
         [0045]    In any of the aforementioned embodiments of the present invention, a stop on demand feature can be added to the mail processing system. Whenever any parameter is measured, there is an inherent error associated with the measurement, the margin of error. Errors can arise from the transitory oscillations or vibrations of the mailpiece weighing transport. In the case of the present invention, an error is always associated with the measured weight of the mailpiece. If a weight break falls within a measurement plus or minus the margin of error, then the mailpiece should be reweighed to verify the measurement. For example, the U.S. Postal Service determines the proper postage for a mailpiece based on weight in one ounce increments, or weight breaks. A first class letter weighing one ounce or less requires thirty-four cents postage. If a letter weighs more than one ounce (approximately twenty-eight grams), then the postage increases to fifty-five cents. Thus it is critical for the weights to be accurately measured when the measured weights fall within the margin of error of the system. This problem solved in three ways. The first is to apply more postage than necessary. This method is not optimal because it results in added unnecessary expense. The second way is to divert the mailpiece down a separate path and have the mailpiece reweighed by hand or a more sensitive system. The third way is to stop the transport and allow the load cell to stabilize. After stabilization, the mailpiece can be reweighed. To capture this criticality, a stop on demand algorithm can be implemented in the mail processing system controller  100 .  
         [0046]    Referring to FIG. 10, at step  1000 , the mailpiece weighing transport is initiated. At step  1020 , a decision is made as to whether the first sensor  866  is blocked by mailpiece  804 . If the first sensor  866  is blocked, then mailpiece  804  may need to be removed from the mailpiece weighing transport. If not, mailpiece  804  proceeds to the load cell and the weighing begins, step  1030 . After weighing, the mailpiece  804  progresses along the transport path. At step  1040 , a decision is made as to whether the second sensor  868  is blocked by mailpiece  804 . If so, the mailpiece may not be removed. If not, the stop-on-demand system progresses to step  1050 . At this step, a decision is made as to whether the weight obtained was satisfactory. An unsatisfactory weight, for example, would be one that has a postal weight break within the margin of error of the weight obtained. If an unsatisfactory weight is obtained, the transport is stopped in step  1060 . Then, the weighing is continued at step  1070 . Continued weighing can include the reweighing of mailpiece  804 . Step  1080  allows for a loop that keeps reweighing mailpiece  804  until a satisfactory weight is obtained. Only when a satisfactory weight is obtained does mailpiece  804  proceed to step  1090  in which the mailpiece weighing transport  802  is restarted.  
         [0047]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices, shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims. For example while the preferred embodiment is described in connection with a mail handling machine, any apparatus for handling articles can utilize the principles of the invention. Additionally, while a mailpiece weighing transport utilizing belts is described it is known to use rollers and other transport mechanisms.