Sequential stamping of strip material
United States Patent 1 1 m1 3,880,034 Sa olsk A r. 29, 1975 P y P SEQUENTIAL STAMPING 0F STRIP 3.248.978 5ll966 Muller v. 83/36 MATERAL 3.69l.887 9/l972 Roch 83/2) X [75] Inventor: Roger Sapolsky, Saint Gratien.  
  France Primary Examiner-Donald R. Schran Assignee Gulf and western Manu&#39;acmri&#39;g Attorney. Agent. or Firm-Charles I. Sherman Company (Hastings), Southfield. 57 ABSTRACT [22] Filed: May 3. I974 bod d f f d r d A met an apparatus or ee ing to a me -axis [2]] Appl 466581 punch. successive sections of a strip of flexible material for the purpose of punching out from the strip [30] Foreign Application P i it D t plates of a predetermined size and shape said strip May 9 I973 France J67 being punched out in a staggered pattern along three rows of axes which are parallel to the median longitu- 52 us. Cl. a3/22o- 83/36 83/240- the The is in 33/234. 3 &#39;83/3562&#39; particular. to the stamping out of circular plates of 511 lnt.Cl. azni 28/08 T3261 1/40 idemica&#39; a which F of Search 3 2 0 249 2 9 35 plates are [0 be shaped in their final form by SUCCCS- 83/3562 206 6 sive stampings performed by a series of inter-related punches located in a transfer machine. [56] References Cited 7 Claims. 6 Drawing Figures PATENTEUAPRZSISTS 3. 880.034  
 sum 3 or 4 SEQUENTIAL STAMPING OF STRIP MATERIAL BACKGROUND OF THE INVENTION There are known devices which stamp out a series of flat pieces of identical shape and size. especially circular plates. from a sheet of material such as metal which is presented to a fixed-axis punch in the form of a strip or continuous ribbon unrolled on a horizontal surface. In these devices. the unrolling of said ribbon on said horizontal surface is periodically interrupted to allow said punch to stamp out a piece of material from the ribbon surface thus fed to the punch. After the piece has been stamped out and removed. and the punch has returned to its rest position. the ribbon is displaced in a predetermined direction and distance and. at the end of the movement. maintained in a fixed position so as to allow a repetition ofthe preceding stamping process.  
  In most of the already known devices of this kind. the punch. which generally works in conjunction with a massive press. is positioned in such a manner that its vertical longitudinal axis is fixed. while the ribbon of flexible and thus more manageable material is displaced with respect to the fixed axis of the punch. said displacement being either to an axis parallel to the median longitudinal axis of the ribbon. thus allowing said ribbon to be stamped out in identical successive sections so as to leave the ribbon with a number of identical holes that follow each other in regular intervals along axes which are parallel to the longitudinal axis of the ribbon; or as is most often the case said movement is first parallel and then perpendicular or at an angle to the median longitudinal axis of the ribbon. a procedure which makes it possible to stamp successive sections and. afterstamping. leaves the ribbon with two rows of holes which. in each row. are aligned parallel to the median axis of the ribbon. while either of the two rows is offset from the third row either on a perpendicular to said median axis, or at an angle to the axis, in a predetermined direction. For an equal quantity of punched-out pieces. these stamping procedures make it possible to unroll only one ribbon instead of two, a fact which permits considerable timesavings, since the number of new ribbons to be mounted on the press is thus cut in half.  
  The invention accordin gly comprises the several steps and the relation of one or more of such steps with respect to each of the others. and the apparatus embodying features of construction. combinations of elements and arrangement of parts which are adapted to effect such step, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.  
 SUMMARY OF THE INVENTION The present invention improves the production capacity of known presses by providing a device which feeds a ribbon to a fixed-axis punch working in conjunction with the press. The ribbon is fed in successive sections to the punch for stamping. on the one hand permitting the ribbon to be stamped along three rows of axes parallel to its median longitudinal axis. whereby the axis of the center row coincides with said median axis. The feeding process occurs in such a manner that the total width of the ribbon is less than the sum of the transverse widths of the stamped-out pieces, so that the proportion of the punched-out surface of the ribbon with respect to its total surface is larger than that obtained with previously known devices. thus achieving savings of material. On the other hand the invention permits less frequent ribbon changes in the corresponding unrolling device and thus results in less frequent down-time in the press itself.  
  The apparatus according to the invention is designed to feed a strip of material to a punch which has a fixed vertical axis and is mounted on the bedplate ofa press which drives the punch. The strip of material is in the form of a ribbon which has been previously rolled-up by the coiling component of a strip-feed apparatus which unrolls the ribbon in successive steps and works in conjunction with the bedplate of the press.  
  The strip-feed apparatus according to the invention comprises a horizontal platform. the surface of which supports and holds the partly unrolled ribbon. The platform is equipped to guide the ribbon in displacements that are parallel to the ribbon longitudinal axis. and in successive steps of a predetermined value which is a function of the width of the ribbon. The horizontal platform is horizontally movable in a direction perpendicular to the longitudinal axis of the ribbon and is equipped for this purpose with guiding and driving means. The platform is thus capable of moving periodically. cyclically and successively to three different fixed positions. namely a first extreme position. a second extreme position and a third median intermediary position between the two preceding ones. In the latter position the longitudinal axis of the horizontal platform coincides with the longitudinal axis ofthe strip of material when the strip is in contact with the platform. and the strip longitudinal axis intersects the vertical axis of the punch. the other two extreme positions being symmetrical with respect to the median position.  
  A horizontal die-holding platform is fixed with re spect to the bedplate of the press and is adapted to receive the ribbon when the latter leaves the movable horizontal platform. The die-holding platform is located downstream (in regard to the direction of the ribbon feed) ofthe movable platform lllSLlCll a manner as to face the punch and is in a plane which is an extension of the horizontal surface of the movable platform. The strip of material is located on the fixed platform after leaving the movable platform for the purpose of being stamped by the punch.  
  A means is provided to synchronize and coordinate the movements of the movable horizontal platform. the ribbon-feed device and the punch so that when the movable platform is displaced from its first to its second extreme position, the ribbon is firmly held on the movable platform while continuing to be fed out of the feeding device. Accordingly during the displacement of the movable platform from its second to its third or median position, the ribbon advances simultaneously by a distance equal to one incremental step and, during the ribbons return from the third or median position to its first extreme position. the ribbon also advances by one step. The movable platform remains stationary in each of these three positions when the position is reached, and resumes its movement towards the next position as soon as the punch has perforated the part of the ribbon positioned on the fixed platform facing the punch.  
  The drive mechanism of the movable horizontal platform preferably consists of a double-action hydraulic jack. The median extended position of the jack shaft corresponds to the intermediary position of the movable horizontal platform. while the extreme positions of the platform are obtained one by the retraction. and the other by the extension of the shaft of said jack.  
  Preferably a hydraulic-pressure blocking jack is positioned parallel to the drive jack for the movable platform. The shaft of the blocking jack has a stop plate mounted at the terminal end. and its length is such that when the movable platform is moved from its second extreme position to the median position. the blocking jack shaft is in its extended position. The movable platform comes to rest against the stop plate and is thus held precisely in the median position. When the movable platform returns from its median position to its first extreme position. the shaft of the blocking jack is pulled back. The movements of the blocking jack are synchronized and coordinated with the movements of the horizontal platform. the strip of material. and the punch. in such a manner that when the platform is in its median position. the return movement of the punch to its initial position acts at the same time to retract the shaft of the drive jack and of the shaft of the blocking jack. When the platform is in its first extreme position, the return of the punch to its initial rest position causes at the same time an extension of the shaft of the drive jack and an extension of the shaft of the blocking jack to positions which said shafts will retain until the mov able platform returns to its median position.  
  The movable horizontal platform preferably incorporates at least one assembly consisting of two shock absorbers. each linked to the platform and symmetric with each other about the longitudinal median plane of symmetry of said platform. The exterior end of the shaft of each shock absorber is equipped with a stop plate. one of which cooperates at a first extreme position of the platform with a first fixed stop plate attached to the bedplate of the machine. said first fixed stop plate being adjustable by means of a first adjusting device. Theothe; stop plate cooperates at a second extreme position of the movable platform with a second fixed stop plate attached to the bedplate of the ma chine. said second fixed stop plate being adjustable by means of a second adjusting device which. in turn. cooperates with the first adjusting device in such a manner that the two fixed stops remain symmetrical with respect to each other.  
  The movable horizontal platform also preferably incorporates a third shock absorber linked to said platform and having a shaft which is equipped at its exterior end with a stop plate. This stop plate is located opposite the terminal stop plate of the shaft of the jack which blocks the movable platform in its median position and cooperates therewith in said median position.  
 BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the nature and objects of the invention. reference should be had to the following detailed description taken in connection with the accompanying drawings in which:  
  FIG. 1 is a schematic side elevation view of an apparatus for stamping a strip of sheet metal in accordance with the invention;  
  FIG. 2 is an enlarged top plan view of the movable platform of the apparatus shown in FIG. 1;  
  FIG. 3 is a top plan view of the movable platform showing the platform is in a first extreme position.  
  FIG. 4 is a top plan view of the movable platform in a second extreme position;  
  FIG. 5 is a top plan view of the movable platform in a median position;  
  FIG. 6 is a plan view of a section of a strip after stamping in accordance with the invention.  
  Similar reference characters refer to similar parts throughout the several views of the drawings.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. I, the apparatus of the invention is preferably designed for perforating a strip of ma terial such as sheet metal. and comprises :1 preferably horizontal platform I mounted on a bedplate B of a press equipped with a cutting punch P which is axially movable along a fixed axis A-A. Platform 1 acts to support the strip 6 which is fed to the platform along the strips longitudinal axis XX. Platform 1 is movable by horizontal displacement perpendicular to the longitudinal axis X-X and thus perpendicular to the direction of movement of the strip. its movements alternating successively from one side of axis X-X to the other. Strip 6 is continuously unrolled from a drum T around which it has previously been rolled. and which is part ofa feeding device. Strip 6 may be guided during feeding by appropriate, known guide devices (not shown) attached to the press. until the strip reaches platform 1 upon which it comes to rest in the plane of said platform. The strip is also guided laterally by appropriate. known guide devices such as slides or assemblies of vertical rollers (not shown) whose lateral spacing is adjustable in such a manner that they can be adjusted to the width of the strip being fed. After being positioned on platform I. strip 6 is held between two rollers Ia and lb whose axes are parallel to each other and perpendicular to axis X-X. Rollers la and lb work in conjunction with platform I. and the strip is thus gripped between rollers la and lb in close contact with them. Rollers Ia and lb may be components of any of a number of known devices for feeding strip incrementally. as for example a pendulum and coasting wheel type which operates in such a manner that when said coasting wheel is in its blocking position. the sheet metal strip is maintained in a fixed position. the rollers are blocked and tie sheet metal is firmly held against platform I while strip 6 is being fed between drum T and rollers la and lb. On the other hand. when rollers la and lb are driven in rotation. they cause strip 6 to advance by one step on the platform before again being blocked. and so forth. The rate of feed of strip 6 and its rate of advancement on platform 1 are coordinated in such a manner that the average amplitude of the loop formed in strip 6 between drum T and rollers la and lb remains essentially constant.  
  Horizontal platform I is transversely movable by at least one double-action jack. preferably of the hydraulic type. attached to bedplate B of the press and fixed with respect to it. whereby the movable shaft of said double-action jack may operate in conjunction with the platform. The longitudinal axis of the shaft is preferably perpendicular to. or in a perpendicular plane with. the axis of feed of the strip. In its lateral movements. platform 1 is preferably guided in a horizontal plane by slides 4 of a conventional type. which are attached to the bedplate of of the press. Most preferably. however. the transverse movements of platform 1 are effected by two identical, double-action hydraulic jacks 2 and 5 which may be located on the same side of the platform.  
 symmetric about the median transverse plane thereof. and parallel to the direction of platform movement. The movements ofjacks 2 and 5 are synchronized with each other. The transverse movements of platform I are such that the platform successively and in a cyclical manner occupies three positions. In a first position which results from the retraction of shafts 3 and 7 of drive jacks 2 and S, the platform is located as shown in FIG. 3 next to a longitudinal upright 8 of a support frame 9 adjacent drive jacks 2 and 5. In a second position resulting from maximum extension of shafts 3 and 7 of drive jacks 2 and 5. platform I is positioned as shown in FIG. 2 next to a second longitudinal upright 10 of support frame 9. opposite drive jacks 2 and 5. In a third position (FIG. 5) platform 1 is located at the median position of shafts 3 and 7 of drive jacks 2 and 5. that is to say at that position in which the shafts of the drive jacks are halfway extended. Since the latter position of the shafts cannot always be achieved in an absolutely precise manner. and so as to counteract the slight imprecision resulting therefrom. a third positioning jack I1 is placed between jacks 2 and 5. preferably midway between the two. Positioning jack I1 is preferably of the double-action type. the end of its shaft 12 being equipped with a stop plate I3. The length of shaft 12 is equal to half the length of shafts 3 and 7 of drive jacks 2 and 5. and jack II is positioned in such a manner that when shaft 12 is completely extended. stop plate 13 cooperates with the adjacent lateral edge of horizontal platform I and keeps the platform blocked in its third or median position (FIG. 5). When platform I is brought back to its first position (FIG. 3). the retraction of shafts 3 and 7 causes the introduction of fluid into the forward chamber ofjack 11 and the evacuation of fluid from the rear chamber thereof. resulting in complete retraction of shaft I2 of jack 11.  
  That part of strip 6 which extends downstream (in the direction of strip feed) of platform I rests on a fixed level surface (not shown) consisting. for example. of a second horizontal platform. The second platform is fixed with respect to bedplate B of the press and linked to it by any known appropriate means. and is also on the same plane as the surface of movable platform 1. In addition, the median axis of the fixed platform coincides with that of movable platform I when the latter is in its median position and. as mentioned above. is located in the vertical plane that runs through the axis of platform 1 and thus through the longitudinal axis of strip 6. The fixed platform preferably contains a contoured die which corresponds to the contours of punch P. the contours commonly being. for example. circular in shape as shown on the drawings.  
  In the two extreme positions of movable platform I. the vertical plane running through the fixed axis A-A of punch P intersects the plane of strip 6 along two axes. YY and 2-2, which. as shown in FIG. 6. are parallel to the median longitudinal axis X-X and lo cated on either side at an equal distance. Still referring to FIG. 6. the locations of axis YY and 2-2 are matched to the punch diameter in such a manner that. in each of the corresponding positions of movable platform I, the apparent contour of the hole that is to be punched out which is the orthogonal projection of the apparent contour of the punch upon the strip of material is tangential or essentially tangential with the corresponding edge of the strip 6.  
  The stamping of strip 6. as in the shape of circular plates. is performed in the following manner. With movable platform I immobolized in its first extreme position as shown in FIG. 3. strip 6 is itself immobilized in such a position that the axis A-A (FIG. I of punch P intersects the axis YY. Punch P is then actuated to perforate strip 6 in the shape of a circle which is essentially tangential with respect to the corresponding edge of the strip.  
  Once this perforation is completed. movable platform I is indexed to its second extreme position as shown in FIG. 4. in which strip 6 is presented to punch P in such a manner that the fixed axis AA of punch P intersects the axis ZZ. Punch P is again actuated to perforate strip 6 in the shape ofa circle which is essentially tangential with the opposite edge of the strip. that is the edge opposite the one perforated in the preceding step. The second perforation is spaced from the first along an axis that is perpendicular to the longitudinal axis of the strip and equal to the distance between axis YY and axis Z-Z.  
  After the second circular plate has been punched. strip 6 is advanced along axis XX by a distance that is slightly greater than the radius of one perforation; this constitutes one forward increment. Platform 1 is then indexed to its third position (FIG. 5] in which the fixed axis A-A of punch P intersects longitudinal axis X-X of strip 6. When this position is reached. punch P is again actuated to cut from strip 6 a circular plate having the same diameter as the preceding ones. The circular contour of the latter perforation. as shown in FIG. 5. is tangential or nearly tangential with the circular contours of the perforations made in strip 6 by the two preceding operations.  
  Once punching of the third circular plate has been completed. strip 6 is again advanced by one increment. Platform l is brought back to its first extreme position from which a new three-plate stamping cycle is initiated in the same manner as described above. A new plate is punched out tangentially or nearly tangentiallywith the corresponding edge of the strip. and the circular contour of the perforation left by the punch is accordingly tangential or nearly tangential with the corresponding edge of the strip. with the circular contour of the perforation made when platform I was in the preceding position. and with the circular contour of the perforation left by the punching step which occurred at the beginning of the preceding cycle.  
  In this manner. the circular contours of all adjacent perforations are tangential or nearly tangential with each other. and are arranged in such a manner that the circles which correspond to the perforations made in the successive positions of the carriage. have their centers arranged in rows. This arrangement results from the fact that the centers of the circles with equal radiuses are arranged in groups of three positioned at the apexes of a network of equilateral triangles. In this manner. the proportion of useful surface. that is to say the ratio of punched-out surface of the strip. with respect to the total surface of said strip. is the optimum that can possibly be achieved when cutting out circular sections along three adjacent longitudinal lines.  
  During lateral displacement as effected by movement of movable platform I, strip 6 is subjected to some elastic flexing in its plane. but such a flexing is easily accommodated by the loop in the strip which forms be- 7 tween drum T and rollers la and lb as shown in FIG.  
  The above-described perforating procedure requires coordination and synchronization of the transverse movements of the platform and the longitudinal. incremental forward movement of the strip. For this purpose. the apparatus of the invention is equipped with a number of conventional mechanisms designed to automatically coordinate and synchronize these movements with each other and with those of the punch. In particular. the strip feed is halted when the shafts of the drive jacks of the platform move from their retracted positions to their respective extended positions to cause the platform to index from its first to its second extreme position. The shaft of the positioning jack moves at the same time to its extended position. When the punch has returned to its initial position after completing the stamping operation in the second position of the platform. the above mentioned synchronization mechanisms cause the simultaneous incremental advance of the strip and the retraction of the drive jacks to the median index position of the platform. As soon as the latter two movements are accomplished. the strip is punched in its median position. When this punching operation is completed and the punch has returned to its initial position. the synchronization mechanisms cause the simultaneous and complete retraction of the shafts of all three jacks. this movement bringing the platform (and thus the strip) back to its first extreme position. from where the punching process on the strip continues automatically and cyclically in the abovedescribed manner.  
  It is of course obvious that the width of the strip that is to be punched must be selectively chosen with relation to the desired diameter of the circular plates, said diameter. in turn. defining the forward incremental feed of the strip. The strip-guide devices which are mounted on the movable platform and which have an adjustable lateral span. allow the platform to accommodate strip of different widths and to center such strip precisely. These devices also adjust the incremental feed to the width of the strip by appropriately adjusting the corresponding elements of the synchronization devices which coordinate and synchronize the movements of the strip-supporting and guiding platform together with those of the feed device for the strip.  
  The above description of the apparatus of the invention relates to a specific example whereby circular plates are punched from the strip, all the plates having an identical diameter. However, it will be obvious to those skilled in the art that identical plates having a non-circular shape can also be punched out in a similar manner by using an appropriately shaped punch. and by sequentially orienting the punch relative to the strip in a similar manner to permit optimum utilization of the strip material.  
  Preferably. the apparatus of the invention is equipped with shock absorbers designed to suppress vibrations in the movable platform at either of the extreme positions thereof. These shock absorbers 14a and 14b (FIG. 2) are of conventional construction and are conventionally secured. for example. underneath the platform. Shock absorbers 14a and 14b are preferably identical and are placed symmetrically about a plane which coincides with the median plane of the platform. that is to say about the vertical plane which runs through the X-)( axis when the platform is in its median position (see FIG. 2). The exterior ends of the shafts lSu and 15b thereof are equipped with stop plates 16a and 1612 which come to rest against corresponding stop plates 17a and 17b secured to the bedplate of the press. Plates 17a and I7]; are adjustably located at predetermined positions which are determined by the amplitude of the transverse movement of the movable platform. said amplitude being in turn a function of the width of the strip to be punched. Stop plates 17a and [7b are positioned in such a manner that they remain symmetrical with each other about the plane which coincides with the median plane X-X of the platform when the latter is in its median position.  
  Each of the two stop plates [70 and 17b is adjusted to its desired position by conventional means. for example. of the guided screw and nut&#34; type. The vibrations occuring in the movable platform when it moves to a median position are also preferably dampened by equipping the platform with a shock absorber l8 similar to the ones described above. Shock absorber 18 is secured to the platform and positioned in such a manner that the axis of its shaft 19 which ends in a stop plate 20 is located opposite of stop plate 13 of shaft 12 of jack II and coincides with the axis of the latter.  
  For the purpose of maintaining fixed stop plate 17a and 17b symmetric to each other about plane X-X. the two adjusting devices for the stop plates cooperate with each other by means of a common drive element which imparts equal speeds but opposite directions of rotation to the drive screws of the guided nuts connected to the corresponding stop plates 17a and 17b.  
  it will thus be seen that the objects set forth above. among those made apparent from the preceding description. are efficiently attained and. since certain changes may be made in carrying out the above method and in the constructions set forth without departing from the scope of the invention. it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.  
  It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described. and all statements of the scope of the invention. which. as a matter of language. might be said to fall therebetween.  
  Having described my invention. what I claim as new and desire to secure by Letters Patent is:  
  l. Apparatus for feeding and indexing continuous strip relative to a material working device such as a punch or the like whereby said device may sequentially operate along three parallel longitudinal axes of said strip, comprising. in combination:  
 A. means for feeding said strip in increments.  
 B. means for supporting said strip in operative position adjacent said material working device.  
 C. indexing means comprising l. a platform for supporting said strip.  
 2. means for holding said strip to said platform between successive incremental feeds thereof.  
 3. lateral guide means for guiding said strip over said platform.  
 4. drive means for sequentially and cyclically indexing said platform and the strip thereon be tween three positions. the first said position being one in which a first longitudinal axis of said strip lying to one side of the median longitudinal axis thereof is aligned with said material working device. the second said position being one in which a second longitudinal axis of said strip lying to the other side of the median longitudinal axis thereof and equidistant therefrom is aligned with said material working device. and the third said position being one in which the median longitudinal axis of said strip is aligned with said material working device. and  
 D. means for synchronizing and coordinating the feed of said strip. the actuation of said material working device and the operation of said drive means.  
  2. Apparatus as defined in claim 1 wherein said drive means comprises at least one hydraulic drive jack. the shaft of which is connected with said platform. said first and second positions of said platform being achieved at one or the other of the fully extended or fully retracted positions of said shaft. said third position of said platform being achieved at the median extended position of said shaft.  
  3. Apparatus as defined in claim 2 including two such hydraulic jacks. symmetrically connected to said platform about a median plane oriented transverse to the direction of strip feed thereover and parallel to the direction of platform movement.  
  4. Apparatus as defined in claim 2 including positioning means affording precise location of said platform in said third. median position.  
  5. Apparatus as defined in claim 4 wherein said positioning means comprises a hydraulic positioning jack mounted parallel to said drive jack. the end of the shaft of said positioning jack when fully extended being in position to make contact with said platform. and being of a length to accurately stop said platform in said third. median position.  
  6. Apparatus as defined in claim 1 including shock absorbing means interacting with said platform at each of said three positions to suppress vibrations resulting from the abrupt stop of said platform at each said position.  
  7. Apparatus for feeding and indexing continuous strip relative to a stamping device whereby said device may sequentially operate along three parallel longitudinal axis of said strip. comprising. in combination:  
 A. means for feeding said strip in increments.  
 B. means for supporting said strip in operative position adjacent said material working device,  
 C. indexing means comprising l. a platform for supporting said strip.  
 2. means for holding said strip to said platform between successive incremental feeds thereof.  
 3. lateral guide means for guiding said strip over said platform.  
 4. drive means comprising at least one hydraulic drive jack. the shaft of which is connected with said platform. for sequentially and cyclically indexing said platform between three positions. the first said position being one in which a first longitudinal axis of said strip lying to one side of the median longitudinal axis thereof is aligned with said device. the second said position being one in which a second longitudinal axis of said strip lying to the other side of the median longitudinal axis thereof and equidistant therefrom is aligned with said material working device. said first and second positions being achieved at one or the other of the fully extended or fully retracted positions of said shaft. and the third said position being one in which the median longitudinal axis of said strip is aligned with said device. said third position being achieved at the median extended position of said shaft.  
 D. shock absorbing means interacting with said platform at each of said three positions to suppress vibrations resulting from the abrupt stop of said platform at each said position. and  
 E. means for synchronizing and coordinating the feed of said strip. the actuation of said device and the operation of said drive means.