Abstract:
An apparatus for transporting a bundle of signatures moving continuously on a saddle chain to a working station includes an indexing chain moving with variable speed, and a clamping unit for keeping the bundle of signatures at a predetermined position on the indexing chain; a method of operating the apparatus; and a saddle binding machine incorporating the apparatus.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to transport apparatus particularly for transporting signatures from a continuously moving saddle chain of a saddle binding machine to a working station. 
     For the production of bound printed products, such as books, periodicals, magazines, and so forth, transport and gathering devices are well known. After collating single sheets or signatures on a gathering device, the collated bundles have to be fed by a transport device to further processing stations such as a trimming or stitching station. 
     A known transport device for feeding a bundle of collated signatures, a so-called book, to a further working station uses a shuttle assembly to move the bundle of signatures to a stitching station. The shuttle assembly grips the bundle and moves it to the stitching station where it is released. Then, the shuttle mechanism returns to grip the next succeeding bundle of signatures. When the shuttle mechanism engages the next bundle, it also engages the previously moved bundle of signatures located at the stitching station and moves the signatures, which in the meantime have been stitched, to a delivery station, while the next bundle is moved to the stitching station. A transfer device and a stitching machine of this general construction is known from U.S. Pat. No. 3,317,026. The existing systems used on many saddle stitchers use a so-called reciprocating gripper system. It comprises a row of grippers which, when closed, press against the outside of the book. These grippers are connected to a “backup” bar on the inside of the book, so that one half of the book is trapped between the grippers and this “backup” bar. The grippers open, in order to release the book at the stitching station and move back in their open condition. The grippers close on the continuously moving book on the saddle chain when they start to move forward again. In this way, they accelerate the books away from the conveyer chain and stop them at the stitching position. The whole gripper and backup assembly is supported on a linear slide and driven backward and forward by a crank mechanism. 
     This system, however, comprises a relatively large reciprocating mass which requires heavy support frames and a lubricated slide system. When the assembly is driven from a crank, velocities cannot easily be optimized due to the fact that a crank is only capable of simple harmonic motions. Finally, as the gripper and backup bar assembly can only contact the inner half of the book, the higher speed outside of the book is uncontrolled and this tends to cause the spine of the book to move off the saddle apex during quick. deceleration resulting in off-center stitching. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a new and improved method of transporting and transport apparatus, especially for transporting signatures, from a continuously moving chain to a working station. 
     With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, an apparatus for transporting a bundle of signatures moving continuously on a saddle chain to a working station, comprising an indexing chain moving with variable speed, and a clamping unit for keeping the bundle of signatures at a predetermined position on the indexing chain. 
     In accordance with another feature of the invention, the indexing chain succeeds the saddle chain. 
     In accordance with a further feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes a gripper element mounted on the indexing chain. 
     In accordance with an added feature of the invention, the apparatus includes a linear cam. 
     In accordance with an additional feature of the invention, the cam is operatively engageable with the gripper elements for opening and closing the gripper elements. 
     In accordance with yet another feature of the invention, the clamping unit for keeping the signatures at a predetermined position includes a belt for keeping the bundle of signatures in close contact with the indexing chain, the belt being disposed to at least one side of the indexing chain. 
     In accordance with yet a further feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes rollers for keeping the signatures in close contact with the indexing chain at least on one side of the indexing chain. 
     In accordance with yet an added feature of the invention, the clamping unit for keeping the bundle of signatures at a predetermined position includes at least one blowing device for blowing air to the bundle of signatures moving on the indexing chain, the at least one blowing device being located on at least one side of the indexing chain. 
     In accordance with yet an additional feature of the invention, the blowing device includes a nozzle. 
     In accordance with still another feature of the invention, the clamping unit for keeping the bundle of signatures at predetermined positions comprises feeder pins. 
     In accordance with another aspect of the invention, there is provided a method for transporting a bundle of signatures moving continuously on a saddle chain to a working station, which comprises the steps of feeding a bundle of signatures with continuous speed to a transfer point, transferring the bundle of signatures from the continuously moving saddle chain to an indexing chain moving with variable speed, acting upon the bundle of signatures in order to keep the bundle of signatures in a definite position on the indexing chain, and moving the bundle of signatures on the indexing chain with a variable velocity profile to the working station. 
     In accordance with a further mode, the method of the invention includes the step of acting upon the bundle of signatures by a clamping unit for keeping the bundle of signatures at a predetermined position whereat the clamping unit moves with substantially the same velocity profile as the indexing chain. 
     In accordance with an added mode, the method includes performing the step of acting upon the bundle of signatures by a clamping unit blowing air onto the bundle of signatures, the clamping unit being disposed in a stationary manner at a side of the indexing chain. 
     In accordance with an additional mode, the method of the invention includes, during the transfer of the bundle of signatures from the saddle chain to the indexing chain, maintaining the velocity of the indexing chain substantially the same as the velocity of the saddle chain. 
     In accordance with a concomitant aspect of the invention, there is provided a saddle binding machine having a signature conveyor for conveying and gathering a plurality of signatures, comprising a transport apparatus having at least one of the foregoing features. 
     The invention of the instant application is thus especially directed to transport apparatus for transporting a bundle of moving signatures from a first moving chain, a so-called saddle chain, to a working station. When a number of gathered signatures, hanging upon one another on the continuously driven saddle chain, reach the point at which this bundle of signatures is to be transferred to the working station, the transport apparatus transports this bundle from the continuously driven saddle chain to the working station. This transport apparatus succeeds the saddle chain and is driven independently from the saddle chain. It comprises a second moving chain, a so-called indexing chain, which is driven with a velocity profile having variable speed. Furthermore, the transport apparatus according to the invention preferably comprises a devikce for keeping the bundle of signatures at predetermined positions on the indexing chain. At the time of the transfer of a bundle of signatures from the continuously moving first chain, namely a saddle chain, to the second chain, namely an indexing chain, that has a velocity profile, the second or indexing chain moves with the same speed as the first or saddle chain. Just after the back or trailing edge of the bundle of signatures has passed the transfer point, a device for keeping the bundles of signatures at registered positions on the indexing chain acts upon the bundle of signatures and keeps acting thereon at least as long as the working step lasts. After that, the indexing chain speeds up according to a predetermined velocity profile, accelerates the bundle of signatures away from the continuously moving saddle chain and brings the bundle of signatures to a working station, e. g. a stitching station. Before the bundle reaches the working station, the indexing chain is decelerated and stops at a position whereat the further working step, e. g. stitching, is to be performed. After this working process has been finished, the indexing chain accelerates again and moves the bundle of signatures to a second working station or to a transfer position where the bundle of signatures is transferred to a final working station or to another transport device. During this whole procedure, the device for keeping the bundle of signatures at a predetermined position on the indexing chain acts upon the bundles of signatures. This keeps the bundles of signatures at registered positions on the indexing chain during the whole feeding and working process. 
     Combining a continuously moving first or saddle chain, on which the bundle is collated, with a second or indexing chain having a variable velocity profile and being arranged so as to succeed to the first continuously moving chain, makes it possible to accelerate the bundle of signatures away from the first continuously moving chain. Thereby, the velocity profile of the second chain can easily be adjusted to the required demands by driving and control equipment coupled to the second chain. The driving and control equipment drive the second chain and control the velocity profile thereof. The device for holding the bundle of signatures at a predetermined position on the second chain ensures a fixed and definite position of the bundles on the moving indexing chain during its movement, as well as during the working process at the working station. As a consequence, this allows high speed and high acceleration of the indexing chain, as well as high speed working at the working station. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a transport apparatus, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
    
    
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plot diagram of a possible velocity profile of an indexing chain according to the invention; 
     FIG. 2 is a fragmentary, diagrammatic side, end and top perspective view of transport apparatus according to the invention; 
     FIG. 3 is an enlarged fragmentary view of FIG. 2 depicting the region of transfer from a saddle chain to the indexing chain in one embodiment of the invention; 
     FIG. 4 a  is an end, side and top perspective view of a gripper element forming part of the invention; 
     FIG. 4 b  is a fragmentary diagrammatic side elevational view of the region of transfer from the saddle chain to the indexing chain in one embodiment of the invention, wherein a gripper element as shown in FIG. 4 a  is used; 
     FIG. 5 is a fragmentary view like that of FIG. 3 depicting the region of transfer from the saddle chain to the indexing chain in an alternative embodiment of the invention; and 
     FIG. 6 is a view similar to that of FIG. 5, but showing a further alternative embodiment of the invention. 
     FIG. 7 is a view similar to that of FIG. 5, showing another embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is shown therein a possible velocity profile of the transport apparatus according to the invention that is diagrammatically illustrated in FIG.  2 . The horizontal axis represents the time and the vertical axis the velocity, both in arbitrary units. A working period is defined by the time interval between t 0  and t 5 . At time to, the velocity of the indexing chain  20  is zero and, at this instant, it starts to move and its velocity increases up to a value v c  at t 1 , where v c  is the velocity of the continuously moving saddle chain  10 . Within the time period between t 1  and t 2  a collated bundle of signatures  12  moving continuously on chain  10  enters the transfer point P (FIG. 2) where the bundle is transferred to the indexing chain  20  which at this time has the same velocity v as the saddle chain  10 . At t 2  the rear or trailing edge of the bundle of signatures is downline from the transfer point P, and the indexing chain  20  accelerates up to t 3  to its maximum speed v m . Within the time interval between t 3  and t 4  the indexing chain decelerates again and the bundle of signatures reaches a stitching station at time t 4  whereat the indexing chain stops. Within the time interval between t 4  and t 5  a working step, e. g. stitching, is done, and after this step has been finished, the bundle of signatures is accelerated away from the further working station at t 5 , which corresponds to t 0  whereat the velocity profile starts again from its very beginning. 
     Referring now in greater detail to FIG. 2, a continuously moving first or saddle chain  10  is shown. On this saddle chain, a bundle of signatures  12  is continuously moving in the direction given by the arrow A where the trailing edge of the bundle  12  is pushed by a pusher finger  22  mounted on the saddle chain  10 . The pusher finger  22  pushes the bundle  12  in the direction of the transfer point P where the saddle chain  10  moves downwardly together with the pusher finger  12 . Therefore, the pusher finger  22  ceases acting upon the bundle  12  and is not driven anymore by the saddle chain  10 . 
     The bundle of signatures  12  now has reached a position which is represented by the position of the bundle of signatures  14  and which lies immediately downline of the transfer point P. At this time, a clamping unit  24  for keeping the signatures  14  in a predetermined position on the indexing chain  20  begins to act upon the bundle of signatures  14  in a manner which will be described in greater detail hereinafter. The bundle of signatures  14  then are transported on the indexing chain  20  with the variable velocity of the indexing chain  20 , while the clamping unit  24  keeps the bundle of signatures  14  at a predetermined position on the indexing chain  20  and does not release from the signatures  14 . In this way, the bundle of signatures  14  is transferred to a stitching station  30 , where they reach a position indicated by the position of the bundle  16 . During a working process, e. g. the stitching process, the clamping unit  24  for keeping the signature at predetermined positions, preferably continues to act upon the signature. After stitching has been done, the bundle of signatures  14  is moved forward with the variable velocity profile of the indexing chain  20  to a position indicated by a bundle of signatures  18  where the bundle of signatures is transferred to another transport device for proceeding with further final working steps. 
     At the transfer point P shown in FIG. 3, a bundle of signatures  12 , moving continuously on the first saddle chain  10 , is transferred to a second saddle chain  20  having a variable velocity profile. The bundle of signatures  12  on the chain  10  is engaged with a pusher finger  22  acting upon the trailing edge of the bundle. As the pusher finger  22  is mounted on the chain  10 , the bundle of signatures  12  is pushed forward with the same continuous velocity of chain  10 , until chain  10  moves downwardly supported by rollers  26  and  28 . At this time, the pusher finger  22  ceases to act upon the trailing edge of the bundle of signatures  12 , and the bundle is transferred to the second chain  20  moving with a variable velocity profile. At the transfer point P, the chain  20  is supported by rollers  31 ,  32 . Clamping units, such as the gripper element  24 , are mounted on the variable moving chain  20  and act upon the trailing edge of the bundle of signatures and thereby clamp the bundle of signatures to fix them in a desired position on the variable moving chain  20 . At the transfer point P, a bundle of signatures having a position corresponding to the position of the bundle  12  is moved forward with constant speed v c . At the time, when the bundle  12  is transferred to the indexing chain  20 , it preferably moves with the same speed v c  as that of the chain  10 . One of the gripper fingers  24  mounted on chain  20  then engages with the trailing edge of transferred bundle of signatures  12 . It therefore does not stop moving forward at the transfer point and is transferred from the continuously moving saddle chain  10  to the indexing chain  20  with substantially the continuous speed v c  of the continuously moving first chain  10 . When the bundle of signatures  12  has passed the transfer point P and may for example have assumed a position given by the position of the bundle of signatures  14 , the bundle of signatures  14  is accelerated away from the saddle chain  10  on the indexing chain  20  where the indexing chain  20  accelerates according to a velocity profile given in FIG. 1 by way of example. 
     Referring now to FIG. 4 a,  a gripper element  40  and an opening and closing mechanism for the gripper unit are shown. The clamping unit  24  (FIG. 2) mounted on the indexing chain  20  may be a gripper element  40  for gripping the signatures  14  and keeping them in a predetermined position on the indexing chain during the whole feeding process. The gripper element  40  comprises a side plate  42  for linking the gripper element  40  to the indexing chain  20 . The side plate  42  is mounted on a U-shaped support  44  having an upper opening  46  and a lower opening  48  which is covered by a plate  49 . A gripper hook  50  extending through the upper opening  46  and the lower opening  48  is coupled to a spring  52  acting upon the hook  50 , in order to apply force to the hook  50  which is directed downwardly or more specifically in the direction towards the lower opening  48 . In this position, the gripper element  40  is in so-called “closed” condition, in which a bundle of signatures can be gripped. This position can be changed to “open” by acting upon the hook  50 , especially by acting upon the lower end of the hook  50  extending through the lower opening  48 . 
     In FIG. 4 b,  three positions  41 ,  43  and  45  of a gripper element  40  mounted on a non-illustrated indexing chain are depicted. A bundle of signatures  14  having just passed the transfer point P and therefore being transferred to the indexing chain, lies just in front of the appearing gripper element  40  which, at this instant, is in the position  41  and moves slightly faster than the bundle of signatures  14 . Upon further movement of the indexing chain  20 , the gripper element  40  reaches the position  43  whereat a linear cam  54 , which is preferably connected to the indexing chain  20 , begins to act upon the lower end of the hook  50 , which extends through the lower opening  48  of the support  44 . As to the shape of the cam, the hook  50  is pushed upwardly and moves through the upper opening  46  and the lower opening  48  and comes into an open position in which the gripper element  40  is able to grip the bundle of signatures  14 . At the same time, the spring  52  of the gripper element  40  in the position  43  is compressed and, as it is coupled to the hook  50  directly or via the plate  49 , it applies a force upon the hook  50  downwardly. Because the bundle of signatures, which has been transferred from the saddle chain to the indexing chain with constant velocity v c , is at this time not driven anymore, the gripper element  40  moves with a velocity which is slightly higher than the velocity of the bundle of signatures. Therefore, the distance between the gripper element  40  and the bundle of signatures  14  decreases until the gripper element  40  begins to act upon the trailing edge of the bundle  14 . 
     According to the shape of the linear cam  54 , the cam stops acting upon the lower end of the hook member  50  upon further movement of the gripping member  40 . Simultaneously, the spring  52  relaxes and the hook  50  begins to move downwardly until it clamps the bundle of signatures  14  at the position  45 . At this point, the bundle of signatures  14  and the gripper element  40  are in close contact and move with the same speed. 
     Using a linear cam coupled to the indexing chain and able to act upon clamping members  40  mounted on the indexing chain and moving with the velocity of the indexing chain, it is possible to open and close these clamping members, in order to grip the bundle of signatures  14  and to keep it in a definite position on the indexing chain during the whole transport and working process. In order to release the bundle of signatures, the same opening and closing mechanism as described hereinabove can be used when the bundle of signatures is to be transported away from the indexing chain. 
     In a further embodiment of the invention, the clamping units  24  for keeping the bundle of signatures at predetermined positions on the indexing chain  20  may be one or more belts  34 , as shown in FIG.  5 . Instead of arranging the gripper elements  40  on the indexing chain  20  as shown in FIGS. 3 and 4, the belt or belts  34  can be arranged aside the saddle chain  20  at a given distance from to the saddle chain, which makes it possible to clamp the bundle of signatures  14  between the belt or belts  34  and the saddle chain  20 . Because the belt or belts  34  move with the same velocity profile as the indexing chain  20 , a signature  14  clamped between the indexing chain  20  and the belt or belts  34  is transported with the velocity profile of the chain  20 . 
     As shown in FIG. 7, it may also be possible to use a plurality of rollers  14   a  arranged at least on one side of the saddle chain  20  and driven with the same velocity profile as chain  20 . Both the belt or belts as well as the rollers, can be arranged either on one or both sides of the indexing chain and act upon the bundle of the signatures  14 , in order to fix the bundle on the chain in a definite position during transport and the working process. 
     In a further embodiment of the invention shown in FIG. 6, the clamping units  24  for keeping the signatures at a predetermined position on the indexing chain  20  are arranged aside the saddle chain  20 , and act upon the bundle of signatures  14  by blowing air at least on one side of the bundle of signatures. For this purpose, blowing devices  38  are mounted at least on one side of the indexing chain  20 . These blowing devices may comprise single nozzles or air tubes having air nozzles for blowing air onto the bundle of signatures moving on the indexing chain  20 . The air that is directed to the bundle of signatures  14  generates pressure on the bundle of signatures  14  so that the bundle of signatures is pressed against the chain  20  and is moved with a velocity profile of the chain  20 , respectively. The spacing of the blowing devices is such that preferably a continuous air flow is directed to the moving bundle of signatures on the indexing chain. 
     In addition to the devices for keeping the signatures at a predetermined position shown in FIGS. 5 and 6, feeder pins  36  may be arranged on the indexing chain  20 , in order to improve the contact of the bundle of signatures to the indexing chain  20  and to improve the transporting behavior. 
     Depending upon the signatures to be transported on the indexing chain  20 , it may also be possible to use the feeder pins  36  mounted on the indexing chain  20  as the only device for keeping the bundle of signatures in close contact with the indexing chain or to use grippers  40  in addition to the belt or belts  34 , the rollers or the blowing devices. 
     It will of course be understood that the invention of the instant application has been described hereinabove purely by way of example and that modifications of detail can be made within the scope of the invention.