Patent Publication Number: US-2022235515-A1

Title: Stacking device and system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 63/141,661, filed on Jan. 26, 2021, which is incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates generally to the transportation and stacking of flexible textile workpieces in a processing line. More specifically, the present disclosure sets forth devices and systems configured to achieve said transportation and stacking. 
     Automated machinery is widely used in the manufacture of thin flexible textile workpieces, such as clothing and apparel like t-shirts. However, some manufacturing steps are still performed manually. 
     For example, in existing processing lines, human actors are often required to manually remove t-shirts from one workstation and manually transfer and stack the t-shirts to be ready for final shipment or further processing. Flexible textile workpieces like t-shirts can be difficult to handle quickly and in a controlled manner. These manual transferring and stacking processes are known to be time-consuming, and result in a poor cost-benefit ratio. 
     Thus, a need exists for a device, system, and/or method which addresses the issues associated with apparel manufacturing discussed above. 
     BRIEF DESCRIPTION 
     The present disclosure is generally directed to a system and device which transports and stacks thin textile workpieces (e.g., clothing) in a processing line. The proposed stacking device includes a conveyor belt wound through a series of rollers which permit horizontal extension of the conveyor path. The extendable conveyor path allows for easy transferring and stacking of the workpieces at a subsequent downstream workstation. 
     Individual workpieces are transported from an upstream workstation, to the conveyor belt of the stacking device, and finally to a downstream workstation which can be configured as a height-adjustable stacking table. Once a workpiece reaches the stacking device from the upstream workstation, the conveyor belt advances the workpiece in the direction of the downstream table. The belt stops advancing forward when a sensor detects the workpiece at a predetermined checkpoint. The length of the conveyor belt remains constant during this stage. 
     Next, a linear actuator powers a carriage forward in the direction of the downstream stacking table, thereby extending the length of the conveyor belt. This can be achieved in part by a sliding cam roller, which moves in the same direction as the carriage to free-up additional portions of the belt. The carriage continues moving forward until it reaches a fully extended position, where the front of the carriage extends a sufficient distance past the front of the downstream stacking table such that the workpiece can be deposited and fully supported on top of the table. 
     Once the carriage is in its fully extended position, the workpiece is deposited onto the table by advancing the conveyor belt forward while simultaneously moving the carriage rearward toward its starting point. The process then restarts with a new workpiece and continues until a stack of workpieces is formed to a desired capacity. As the workpieces accumulate, the height-adjustable table automatically lowers to accommodate the growing stack and ensure that subsequent workpieces continue to stack upon prior workpieces in a neat and orderly manner. Moreover, the height-adjustable table can also include its own separate conveyor belt to move the entire stack of workpieces to another location for further processing. 
     Thus disclosed in various embodiments are systems for handling textile workpieces comprising: a first workstation, a stacking device workstation, and a second workstation. The first workstation includes a support surface from which workpieces are fed. The stacking device workstation includes a stationary frame, a workpiece receiving end, a workpiece depositing end, a linearly displaceable carriage mounted to the stationary frame and moveable between a starting position and a fully extended position, a conveyor belt with a support surface to receive and transfer said workpieces from the first workstation, and a plurality of rollers engaged with the conveyor belt, the plurality of rollers comprising: a driver roller mounted on the stationary frame, at least two fixed support rollers mounted on the stationary frame, a moving roller mounted below the carriage, and a delivery roller mounted on a front end of the carriage, wherein the moving roller and the delivery rollers move relative to the fixed support rollers and stationary frame to change a length of the conveyor belt. The second workstation includes a support surface to receive said workpieces from the workpiece depositing end of the stacking device. 
     The stacking device workstation may further comprise a linear actuator configured to linearly displace the carriage between the starting position and the fully extending position. 
     The stacking device workstation may further comprise a sensor disposed above the stacking device conveyor belt for detecting the presence of workpieces. 
     The second workstation may be a height-adjustable stacking table. The support surface of the second workstation may be positioned below the support surface of the stacking device conveyor belt. 
     The first workstation may be a dryer conveyor positioned upstream of the stacking device, the dryer conveyor including a conveyor belt defining a support surface from which workpieces are fed. The support surface of the dryer conveyor belt may be above or coplanar with the support surface of the stacking device conveyor belt 
     Also disclosed herein are stacking devices for transferring workpieces between an upstream workstation and a downstream workstation, the stacking device comprising: a stationary frame, a workpiece receiving end, and a workpiece depositing end; a linearly displaceable carriage mounted to the stationary frame and moveable between a starting position and a fully extended position; a conveyor belt with a support surface to receive said workpieces from the upstream workstation and transfer said workpieces to the downstream workstation; and a plurality of rollers engaged with the conveyor belt and extending between the sidewalls, the plurality of rollers comprising a driver roller mounted on the stationary frame, at least two fixed support rollers mounted on the stationary frame, a moving roller mounted below the carriage, and a delivery roller mounted on a front end of the carriage, wherein the moving roller and the delivery rollers move relative to the fixed support rollers and stationary frame to change a length of the conveyor belt. 
     The stacking device may further comprise a sensor disposed above the conveyor belt for counting and detecting the presence of workpieces, the sensor being operatively connected with the controller. 
     The stacking device may further comprise a linear actuator and an associated motor configured to move the carriage between the starting position and the fully extending position, the linear actuator and associated motor being operatively connected with the controller. 
     The stacking device may further comprise two mutually parallel sidewalls supported by the stationary frame. The sidewalls can include a cantilevered portion defining a protrusion which extends toward the downstream workstation. The sidewalls may also include longitudinal tracks on which the carriage is guided between the starting position and the fully extended position. 
     The stacking may further comprise a motor for moving the conveyor belt and a controller for controlling the operation of the conveyor belt and the carriage, the motor being operatively connected with the controller. 
     Also disclosed herein are methods for stacking workpieces, comprising: receiving a workpiece at a stacking device that comprises: a stationary frame, a workpiece receiving end, and a workpiece depositing end; a linearly displaceable carriage mounted to the stationary frame and moveable between a starting position and a fully extended position; a conveyor belt with a support surface to receive said workpieces from the upstream workstation and transfer said workpieces to the downstream workstation; and a plurality of rollers engaged with the conveyor belt and extending between the sidewalls, the plurality of rollers comprising a driver roller mounted on the stationary frame, at least two fixed support rollers mounted on the stationary frame, a moving roller mounted below the carriage, and a delivery roller mounted on a front end of the carriage, wherein the moving roller and the delivery rollers move relative to the fixed support rollers and stationary frame to change a length of the conveyor belt; rotating the conveyor belt at a forward feed speed so that the workpiece travels to a front end of the carriage; moving the carriage from the starting position to the fully extended position such that the length of the conveyor belt increases; and moving the conveyor belt at the forward feed speed while moving the carriage from the fully extended position to the starting position, such that the workpiece travels off the conveyor belt while the length of the conveyor belt decreases, and the workpiece is stacked. 
     The carriage may move from the starting position to the fully extended position when a sensor disposed above the stacking device conveyor belt detects the presence of the workpiece at the front end of the carriage. 
     In some embodiments, the forward feed speed of the conveyor belt is reduced to zero while the carriage moves from the starting position to the fully extended position, such that the workpiece is stacked in its original received orientation. 
     In other embodiments, the forward feed speed of the conveyor belt is maintained while the carriage moves from the starting position to the fully extended position, such that the workpiece is flipped from its original received orientation. 
     The stacking device can receive the workpiece from an upstream conveyor belt. A feed speed of the upstream conveyor belt may be from about 60 to 75% of the forward feed speed of the stacking device conveyor belt. 
     These and other non-limiting characteristics of the disclosure are more particularly disclosed below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same. 
         FIG. 1  is a schematic illustration of a system for processing sheet-like workpieces in accordance with the present disclosure, which includes an intermediate transferring and stacking device positioned between associated upstream and downstream workstations. 
         FIG. 2  is a side view illustration showing the stacking device of  FIG. 1 . 
         FIG. 3  is a side view illustration of the stacking device of  FIG. 2  which shows the linear displacement of a carriage and a conveyor belt during a transfer and process of a thin textile workpiece. 
         FIG. 4  is a side view illustration of the stacking device of  FIG. 2 , with the carriage and conveyor belt in a fully extended position. 
         FIG. 5  is a perspective view illustration of a system for processing sheet-like workpieces which includes the stacking device of  FIG. 2  being operatively associated with a downstream height-adjustable stacking table. 
         FIG. 6  is a side view illustration of the system of  FIG. 5 , showing the operative association of the stacking device and the height-adjustable stacking table. 
         FIG. 7  is a side view illustration showing additional detail of the height adjustable stacking table of the system of  FIG. 5 . 
         FIG. 8  is a side view illustration of a system for processing sheet-like workpieces which includes the stacking device of  FIG. 2  operatively associated with an upstream dryer conveyor and the downstream height-adjustable stacking table of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments. 
     Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function. 
     The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. 
     As used in the specification and in the claims, the terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named components/ingredients/steps and permit the presence of other components/ingredients/steps. However, such description should be construed as also describing systems or devices or compositions or processes as “consisting of” and “consisting essentially of” the enumerated components/ingredients/steps, which allows the presence of only the named components/ingredients/steps, along with any unavoidable impurities that might result therefrom, and excludes other components/ingredients/steps. 
     Numerical values in the specification and claims of this application should be understood to include numerical values which are the same when reduced to the same number of significant figures and numerical values which differ from the stated value by less than the experimental error of conventional measurement technique of the type described in the present application to determine the value. 
     All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of “from 2 grams to 10 grams” is inclusive of the endpoints, 2 grams and 10 grams, and all the intermediate values). 
     A value modified by a term or terms, such as “about” and “substantially,” may not be limited to the precise value specified. The modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The term “about” may refer to plus or minus 10% of the indicated number. 
     The terms “upper” and “lower” are relative to each other in location, i.e. an upper component is located at a higher elevation than a lower component. 
     The terms “upstream” and “downstream” are relative to the direction in which a workpiece flows through various components, i.e. the workpiece passes through an upstream component prior to passing through the downstream component. 
     The terms “horizontal” and “vertical” are used to indicate direction relative to an absolute reference, i.e. ground level. However, these terms should not be construed to require structures to be absolutely parallel or absolutely perpendicular to each other, and should permit up to 10° deviation. 
     The term “single” is used herein to indicate that only one of the indicated component is present, and to exclude the presence of additional identical components. For example, “a single widget” should be interpreted to mean one widget is present, and values of, for example, two widgets or three widgets are excluded. 
     As previously mentioned, the present disclosure is directed to a system and device for stacking flexible textile workpieces (e.g., clothing) in a processing line. Referring now to the drawings, various systems are shown for processing sheet-like workpieces  108  in a production line. While the workpieces  108  in the various embodiments are shown and described to specifically comprise items of clothing or apparel such as t-shirts, it is contemplated that other flexible textile objects could similarly be processed by the systems and devices disclosed herein. The stacking systems can be configured to stack the workpieces face-up or face-down, depending on its operation. 
     Referring first to  FIG. 1 , the workpiece processing systems of the present disclosure include a stacking device  102  for transferring, depositing, and stacking the workpieces  108  into one or more stacks  109 . The stacking device  102  is arranged as an intermediate workstation in operative association with downstream workstation  104  and upstream workstation  106 . The upstream workstation  106  is generally configured to feed or transport workpieces  108  to the stacking device  102 . The downstream workstation  104  is generally configured to receive the workpieces in stacked form  109  from the stacking device  102 . 
     The stacking device  102  has a base composed of two mutually parallel sidewalls  110  supported by a frame  112  and has a rectangular configuration which extends between a first or receiving end  114 , and a second or depositing end  116 . Generally, only one sidewall  110  is visible in the drawings, so that all components of the stacking device can be seen more easily. The sidewalls  110  may include a cantilevered portion  118  protruding from the second end  116  which extends toward the downstream workstation  104  when operatively connected therewith. The stacking device  102  includes a conveyor belt  130  which is extendable via a longitudinally/horizontally displaceable carriage  150  which moves back and forth in the direction of arrow  126 . The fully extended position of the carriage  150  and conveyor belt  130  is indicated by the dashed lines outlining the carriage shown in  FIG. 1 . 
       FIG. 2  shows additional details of the stacking device  102 . A sensor  120  for detecting the presence of workpiece  108  and counting the total number of workpieces is mounted to a support arm  122  such that the sensor is generally disposed above the stacking device  102 , or so the sensor can detect workpieces located on the conveyor belt. The sensor  120  is generally located upstream of cantilevered portion  118 . The sensor  120  is in operative connection with a control mechanism  124  for adjusting and controlling the stacking device  102  and its various components. 
     More particularly, the control mechanism  124  of stacking device  102  instructs the operation of the extendable conveyor belt  130  and the longitudinally displaceable carriage  150  which can move in the direction of arrow  128 . The conveyor belt  130  extends between a plurality of rollers  140   a - 140   f  mounted between sidewalls  110  via appropriate bearings (not shown) to provide an upper belt run  132  and a lower belt run  136 . The upper belt run  132  defines a support surface  134  for supporting a workpiece  108  being transported by the stacking device  102 . The lower belt run  136  has a variable length which, as discussed in further detail below, allows for the length of the upper belt run  132  to be extended. The conveyor belt  130  is made of a material with the desired tack for gripping the workpiece. 
     Some of the rollers  140   a - 140   f  are mounted to the sidewalls  110  or frame  112 , while others may be mounted to the carriage  150 . Thus, the plurality of rollers  140   a - 140   f  are configured as being either fixed (i.e., no linear motion) or longitudinally displaceable with respect to the sidewalls  110 . 
     As shown in  FIG. 2 , delivery roller  140   a , also referred to as a displaceable delivery roller, is mounted to the front end  151  of carriage  150  and is thus longitudinally displaceable with respect to the sidewalls  110 . 
     Roller  140   b , also referred to as a moving roller or a sliding cam roller, is mounted to the sidewalls  110  via a sliding cam (not shown) and is positioned below and behind the delivery roller  140   a . The sliding cam permits roller  140   b  to move longitudinally along with the carriage  150  when activated by actuator  160 . As such, the sliding cam roller  140   b  provides tension to the belt  130 , ensuring that no slack occurs during movement of the carriage  150 . 
     Remaining rollers  140   c - 140   f  are mounted in fixed relation to the sidewalls  110  and are thus not longitudinally displaceable with respect thereto. In general, fixed support roller  140   c , fixed support roller  140   d , and driver roller  140   e  are mounted closer to the receiving end  114  than delivery roller  140   a , moving roller  140   b , and fixed support roller  140   f . Moving roller  140   b  can be described as being able to move longitudinally between rollers  140   c - 140   e  and roller  140   f.    
     Fixed support roller  140   c  is mounted adjacent the first end  114  of sidewalls  110 , and acts as the point where the workpiece  108  is received from the upstream workstation  106  shown in  FIG. 1 . Delivery roller  140   a  and fixed support roller  140   c  are mounted in a spaced apart but horizontally co-linear relation such that the upper run  132  of the conveyor belt  130  maintains a horizontal and flat support surface  134 . 
     Fixed support roller  140   d  is mounted below the fixed support roller  140   c  and above driver roller  140   e  and maintains tension in the portion of belt  130  which extends between these three rollers. 
     Driver roller  140   e  is operatively engaged with motor  142  via chain or belt  144  to drive the conveyor belt  130  in the direction indicated by the arrows shown in  FIG. 2 . Moreover, motor  142  is in operative connection with the control mechanism  124  for adjusting and controlling the conveyor belt  130  of the stacking device  102 . It is noted that the motor shaft could be moved to replace the driver roller, such that a chain or belt  144  is not needed. 
     Finally, fixed support roller  140   f  is mounted adjacent the second end  116  of sidewalls  110  to provide support for the lower run  136  of belt  130  along with sliding cam roller  140   b.    
     Rollers  140   a ,  140   c ,  140   e , and  140   f  could be described as contacting an interior surface of conveyor belt  130 , while rollers  140   b  and  140   d  contact the exterior surface of conveyor belt  130 . 
     The carriage  150  includes a vertically extending boss portion  152  operatively connected with a linear guide track  162  of the linear actuator  160 . The actuator  160  is mounted to the sidewalls  110  and extends between a driving end  164  and idler end  166  such that the linear guide track  162  is positioned above and extends generally parallel to conveyor belt  130 . As such, the carriage  150  can move back and forth with respect to the sidewalls  110  and the linear actuator  160  provides for such back and forth movement. 
     A support mechanism for the carriage  150  comprises longitudinal tracks  154  mounted to sidewalls  110  on which the carriage is guided by means of rollers (not shown) so as to be easily longitudinally displaceable and resistant to tilting when acted upon by the actuator  160 . Both the driving and idler ends  164 ,  166  of the actuator  160  include a safety stop (not shown) for abutment with boss  152  to prevent over-extension of the carriage  150  in either direction. The actuator  160  is powered by a motor  170  operatively connected to the driving end  164  via chain or belt  172 . Moreover, motor  170  is in operative connection with the control mechanism  124  for adjusting and controlling the carriage  150  and actuator  160  of the stacking device  102 . 
     The operation of the stacking device  102  of the present disclosure during the transferring, depositing, and stacking process is illustrated in  FIGS. 1-4 . 
     Referring first to  FIG. 1  and  FIG. 2 , the workpiece  108  is moved from upstream workstation  104  to engage the support surface  134  of the upper belt run  132  at the receiving roller  140   c . The carriage  150  is located in the starting or retracted position shown in  FIG. 2 . The workpiece  108  moves forward or to the right in the stacking device  102 , as indicated by the arrow  128  in  FIG. 2 , until a front edge of the workpiece is detected by sensor  120 . The sensor can operate by any suitable means, for example by detecting a change in proximity/depth or a change in color, or generally any means that discriminates between the conveyor belt and the workpiece. The sensor is also typically located near the delivery roller  140   a , such that the workpiece is near the front end of the conveyor belt. When a signal is generated by the sensor  120 , the carriage  150  moves forward in the direction of the arrow  128  while the forward feed speed of the belt  130  is stopped. 
     Referring now to  FIG. 3 , the carriage  150  and delivery roller  140   a  move forward together. Once the resistance of the sliding cam is overcome by the forward force applied by the actuator  160  to move the carriage  150 , the sliding cam roller  140   b  is set in motion, being displaced toward the right. This motion of the sliding cam roller  140   b  maintains the belt  130  taut about rollers  140   c - 140   e  and  140   f . In addition, this motion of the sliding cam roller  140   b  permits the upper belt run  132  to extend in length and the lower belt run  136  to decrease in length. Thus, it should be noted that the longitudinal distance between delivery roller  140   a  and moving roller  140   b  does not remain constant, but is bounded between a minimum value and a maximum value. The support surface  134  defined by the belt  130  maintains its forward speed while the carriage is moving forward, thus keeping satisfactory forward transportation of the workpieces  108 . 
     The carriage  150  is moved further forwardly in the direction of arrow  128  until the carriage reaches its fully extended position illustrated in  FIG. 4 . Once in the fully extended position of  FIG. 4 , the upper belt run  132  has reached its maximum length, the lower belt run  136  has reached its minimum length, and the workpiece  108  is ready for deposition at the downstream workstation. To deposit the workpiece  108 , the carriage  150  and delivery roller  140   a  move rearward in the direction of arrow  129  while the belt  130  restarts its forward feed speed in the direction of arrow  128 . This causes the workpiece  108  to roll off the end of the conveyor belt and be deposited on the downstream workstation  104  (see  FIG. 1 ). The rearward movement speed of the carriage  150  is desirably the same as the forward feed speed of the conveyor belt  130 . As a result, the speed of each workpiece  108  is almost zero as it rolls off the end and is deposited, and there is no pushing or sliding process which could cause the flexible workpieces to fold over or otherwise bunch up and form an unstable, disorderly stack of workpieces. 
     While the carriage  150  moves rearward in the direction of arrow  129 , the sliding cam roller  140   b  is also displaced rearward by a biasing member, such as a spring (not shown). This motion of the sliding cam roller  140   b  maintains the belt  130  taut about rollers  140   c - 140   e  and  140   f , while the upper belt run  132  decreases in length and the lower belt run  136  increases in length. Once the actuator  160  moves the carriage  150  back to its starting position illustrated in  FIG. 2 , a new deposition process as described above can be initiated. The workpieces  108  are thereby securely deposited to form a stack  109  of workpieces (see  FIG. 1 ) as additional deposition cycles are completed. 
     The process described above, where the forward feed speed of the belt  130  is cut to zero as the carriage extends and then restarts as the carriage retracts, causes the workpiece to be deposited in the same orientation as it was placed on the conveyor belt (e.g. face-up). It is also contemplated that the stacking device can be used to flip the workpiece to the opposite orientation (e.g. from face-up to face-down). This could be accomplished by maintaining the forward feed speed of the belt  130  as the carriage extends. 
     It is also noted that because fixed roller  140   c  does not move, the support surface  134  is always present at the receiving end of the device. As a result, a subsequent workpiece could be received by the stacking device  102  while the carriage is still retracting back to its starting position. This could permit the distance between workpieces to be decreased, increasing workpiece throughput. 
     In another embodiment of the present disclosure, a system  200  for processing thin textile workpieces is illustrated in  FIG. 5  and  FIG. 6 . In particular, the system  200  in  FIG. 5  and  FIG. 6  includes the stacking device  102 , which operates in the manner described above, in operative association with a downstream workstation  204 . The downstream workstation  204  is a height-adjustable stacking table which receives the workpieces  108  from the stacking device  102  and supports the workpieces in stacked form  109 . 
     An optional housing arrangement which fully encloses the system  200  is shown in  FIG. 5  as including an upper transparent housing  244  made of clear panels (e.g., LEXAN®) and a lower safety housing  246  for covering the components of the system and protecting users therefrom. The lower housing  246  is not illustrated in  FIG. 6 , to permit easier understanding of the operation of the stacking device  102  with the stacking table  204 . 
     Referring now to  FIG. 6 , the stacking table  204  is comprised of a horizontal platform  210  which is vertically moveable on a support framework  212  via a height adjustment mechanism  230 . The platform  210  can support a conveyor belt  214  to provide the receiving surface on which workpieces  108  are deposited. When operatively associated with the stacking device  102 , the stacking table  204  is generally positioned under the carriage  150 . As such, when the carriage  150  is in its fully extended position (as described above and shown in  FIG. 4 ), the delivery roller  140   a  is positioned above the stacking table  204  at a deposition location where it is desired to form the stack  109 . The vertical distance Z or depositing height through which the workpieces fall during the deposition process can be made relatively small, thereby ensuring a satisfactory depositing of the workpieces without requiring that they be moved, displaced, or pushed. 
       FIG. 7  shows additional details of the stacking table  204 . The platform  210  supports the conveyor belt  214 , which extends between a first end roller  216  and a second end roller  218  to provide an upper belt run  220 . The upper belt run  220  defines a support surface  222  for supporting the stack  109  of workpieces being formed by the stacking device  102 . The second end roller  218  is operatively engaged with motor  224  to drive the conveyor belt  214  in the direction indicated by the arrows shown in  FIG. 7 . Moreover, motor  224  is in operative connection with a control mechanism  226  for adjusting and controlling the feed speed of the conveyor belt  214 . 
     As mentioned above, platform  210  of the stacking table  204  is vertically moveable on support framework  212  via a height adjustment mechanism, such as a rotary screw jack  230 . The rotary screw jack  230  is generally comprised of a screw  232 ; a nut  234  to which platform  210  is mounted, the nut  234  being operatively engaged with the screw for vertical travel up and down the screw; a gear box  236 ; an input sprocket  238 ; and a motor  240  operatively engaged with the input sprocket via chain or belt  242 . Motor  240  is also in operative connection with control mechanism  226  for adjusting and controlling the height of the platform  210  and conveyor belt  214  of the stacking table  204 . It is noted that the motor shaft could be moved and shaped to operate as the screw, such that a chain or belt  242  is not needed. In addition, control mechanism  226  is in operative connection with control mechanism  124  of the stacking device  102 . Alternatively, a single control mechanism  124  can be used for both stacking device  102  and stacking table  204 . 
     Once a workpiece is deposited onto the stacking table  204  by the stacking device  102  in the manner described above, the controller  226  activates the motor  240 , lowering the platform  210  and conveyor belt  214  far enough to receive another workpiece from a subsequent deposition process. The platform  210  and conveyor belt  214  should lower in height by the same amount as the stack  109  increases. When a desired number of workpieces have been stacked by the stacking device  102  onto the conveyor belt  214 , the completed stack  109  can be removed manually or the controller  226  can activate motor  224  to drive the belt  214  forward, moving the completed stack to a final location or to another workstation. In this regard, the controller  226  may instruct the activation of motors  224 / 240  based on the count of workpieces measured by sensor  120 . When the stack  109  is removed, the controller  226  again activates motor  240  to raise the platform  210  and conveyor belt  214  back to the starting position where another stack can be formed. 
     In another embodiment of the present disclosure, a system  300  for processing flexible textile workpieces is shown and described with reference to  FIG. 8 . The system  300  includes the stacking machine  102 , which operates in the manner described above, in operative association with a downstream workstation  204 , which can be configured as a height-adjustable stacking table like that described in  FIGS. 5-7 . The system  300  further includes an additional workstation  306  positioned upstream of the stacking device  102 . The workstation  306  can be a dryer conveyor commonly used in a processing line where ink or paint applied to the workpieces is dried before advancing to a subsequent downstream workstation. 
     The dryer conveyor  306  is generally configured in operative association with the stacking device  102  to feed or transport workpieces  108  to the stacking device. The dryer conveyor  306  is generally comprised of a base frame  310  supporting a conveyor belt  314  which extends between rollers to provide an upper belt run  316 . The upper belt run  316  defines a support surface  318  for supporting the workpieces  108  being delivered by the dryer conveyor  306 . The conveyor belt  314  is moveable in the direction indicated by the arrows shown in  FIG. 8  and is controlled by a control mechanism  324  for adjusting and controlling the feed speed of the conveyor belt. 
     When the dryer conveyor  306  is operatively associated with the stacking device  102 , the support surface  318  of the upper belt run  316  of conveyor belt  314  is located above or coplanar with the support surface  134  defined by the upper belt run  132  of the stacking device conveyor belt  130 . The feed speed of the dryer conveyor belt  314  is generally slower than the speed of the conveyor belt  130  of the stacking device  102 . As such, a satisfactory transference of the workpiece  108  from the dryer conveyor  306  to the stacking device  102  is ensured without a pushing or sliding process which could cause the thin flexible workpieces to fold over or otherwise bunch up, eventually resulting in an unstable, disorderly stack of workpieces formed at the stacking table  204 . 
     In some embodiments, the dryer conveyor belt  314  operates at a feed speed which is about 60 to 75 percent the feed speed of the stacking device conveyor belt  130 . In some particular embodiments, the feed speed of the dryer conveyor belt  314  is about 18 to 22 feet per minute, while the feed speed of the stacking device conveyor belt  130  is about 30 feet per minute. If desired, an air drying or cooling mechanism, such as a fan or air curtain, could be located at the first end of the stacking device which is directed at the conveyor belt for drying/cooling the workpiece received from the dryer conveyor belt. 
     Moreover, control mechanisms  124 ,  226 , and  324  are in operative connection with one another to ensure proper operation between each workstation  102 ,  204 ,  306 . Alternatively, the control mechanism  124  of the stacking device can be configured as the sole controller for each workstation  102 ,  204 ,  306 . In this regard, the extendable conveyor belt  130  of the stacking device  102  can be calibrated with a feed speed which permits optimal operative association with the dryer conveyor belt  314 . Generally, the extendable conveyor belt is calibrated based on factors such as desired speed, length of the workpieces, and/or thickness of the workpieces. Thickness is important for height calibration of the adjustable stacking table  204  which lowers as workpieces are stacked. 
     It is also noted that if desired, slip sheets could be inserted between the textile workpieces. This could be done by laying slip sheets on the conveyor belt between textile workpieces. Such slip sheets can also be deposited on the stack using the same mechanisms and methods described herein. 
     To aid the Patent Office and any readers of this application and any resulting patent in interpreting the claims appended hereto, it is not intended for any of the appended claims or claim elements to invoke 35 U.S.C. § 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim. 
     The present disclosure has been described with reference to exemplary embodiments. Modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the present disclosure be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.