US3768804A

US3768804A - Signature gathering machine with disc separator

Info

Publication number: US3768804A
Application number: US00202152A
Authority: US
Inventors: K Swanson
Original assignee: RR Donnelley and Sons Co
Current assignee: RR Donnelley and Sons Co
Priority date: 1971-11-26
Filing date: 1971-11-26
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

An improved flatwise gathering machine for signatures having a vertical stack of signatures in a supply hopper, there being a horizontal rotating separator disc an edge portion of which is shaped to perform the dual function of deflecting the leading end portion of the bottom signature in the hopper downwardly into the grip of jaws on a transfer drum and simultaneously relieving the weight on the bottom signature by elevating the front of the balance of the stack in the hopper. The cam disc has a mounting flange which receives either of two alternative signature separator adapters, one of which is especially constructed for use with signatures formed in a jaw folder and the other of which is particularly constructed for use with signatures formed in a former board folder.

Description

United States Patent 1 Swanson SIGNATURE GATHERING MACHINE WITH DISC SEPARATOR [75] Inventor: Kermit E. Swanson, Naperville, ll].

[73] Assignee: R. R. Donnelley & Sons Company,

Chicago, Ill.

[22] Filed: Nov. 26, 1971 [21] Appl. No.: 202,152

[52] US. Cl. 271/101 [51] Int. Cl. B65h 3/08 [58] Field of Search 271/41, 29; 270/56, 270/54 [56] References Cited UNITED STATES PATENTS 3,650,525 3/1972 Hageman 271/29 1 3,768,804 Oct. 30, 1973 Primary Examiner-Richard E. Aegerter Att0rneyAxel A. Hofgren et al.

[57] ABSTRACT An improved flatwise gathering machine for signatures having a vertical stack of signatures in a supply hopper, there being a horizontal rotating separator disc an edge portion of which is shaped to perform the dual function of deflecting the leading end portion of the bottom signature in the hopper downwardly into the grip of jaws on a transfer drum and simultaneously relieving the weight on the bottom signature by elevating the front of the balance of the stack in the hopper.

The cam disc has a mounting flange which receives either of two alternative signature separator adapters, one of which is especially constructed for use with signatures formed in a jaw folder and the other of which is particularly constructed for use with signatures formed in a former board folder.

9 Claims, 17 Drawing Figures Patnted Oct. 30, 1973 3,768,804

5 Sheets-Sheet 1.

Patented Oct. 30, 1973 5 Sheets-Sheet 2 Patented Oct. 30, 1973 3,768,804

5 Sheets-Sheet 3 Patented Oct. 30, 1973 3,768,804

5 Sheets-Sheet 4 FIGJO Patented Oct. 30, 1973 3,768,804

FIG. I3 f i FIG 15 205 SIGNATURE GATHERING MACHINE WITH DISC SEPARATOR BACKGROUND OF THE INVENTION The present invention constitutes an improvement upon the type of signature flatwise gathering machine disclosed in Kleineberg et al. US. Pat. No. 2,621,039, issued Dec. 9, 1952. l

The gathering machine of that patent has a cam actuated arrangement of cooperating fingers which swing in and out of the corner area of a stack of signatures in the hopper of a gathering machine, and the fingers are cam actuated so that when they are swung into the stack corner area between the bottom signature in the stack and the next signature above it, one of the fingers is pivoted downwardly to bend down the corner of the bottom signature while the other. finger is pivoted upwardly to elevate the balance of the stack and relieve the pressure on the bottom signature.

The foregoing mechanism of US. Pat. No. 2,621,039 requires a rather complex mechanical linkage system, and lacks any easy means for converting a particular supply box of a gathering machine for use alternatively with jaw formed signatures or signatures formed on a former board. In view of the fact that many printing plants which produce patent bound books may have both kinds of signatures going into a single book, and with different runs having signatures of the different types in different positions, it is important to be able to convert any box of a flat gathering machine quickly from handling one type of signature to handling the other type.

SUMMARY OF THE INVENTION In Kleineberg et al. US. Pat. No. 2,621,039 the signature separating mechanism is particularly illustrated in FIGS. 7 to 10, and that mechanism is operated from a control cam 145 having a groove 147, a cam follower 148 on a follower arm 150, a link 152, a rock arm 154, a rock shaft 96, a rocking link 156 on the rock shaft 96, and a push rod 143 the connection of which with the separator fingers is best seen in FIGS. 8 and 9.

As seen in FIGS. 7 and 8, the fingers C and D swing in and out of the corner of the stack of signatures in the supply hopper, and the finger C then pivots down to bend down the leading end portion ofthe bottom signature while the finger D pivots up to relieve weight on the bottom signature by elevating the front of the balance of the stack. A suction means first pulls down the corner of the bottom signature to make room for the separator fingers to override said corner.

The improvement of the present invention utilizes a single rotating cam separator disc having a lower face which is shaped to deflect the leading end portion of the bottom signature down and an upper face which is shaped to elevate the front of the balance of the stack and thus relieve the weight on the bottom signature. The rotatable cam disc is operated by a simple chain drive directly off the shaft 196 which carries the rotary drum signature extractor E, seen in FIG. 1 of the drawings of US. Pat. No. 2,621,039. This eliminates the control cam 145 and the entire complex linkage system which is necessary to operate the separator fingers C and D.

In addition, jaw formed signatures have their open edges at the front and a separator must penetrate the stack from the side, while formed board signatures board signatures.

The separator cam disc of the present invention may be converted to handle either type of signature merely by removing a one-piece adapter member of one shape and substituting one of another shape.

THE DRAWINGS FIG. 1 is a fragmentary side elevational view of one signature gathering box of a flatwise gathering machine embodying the invention;

FIG. 2 is a fragmentary plan view of the apparatus provided with a separator disc for jaw formed signatures, the location of a stack of signatures being illustrated in dot-dash lines;

FIG. 3 is a schematic view similar to FIG. 2 but showing only the separator disc, signatures and suction grippers immediately before the disc penetrates the stack;

FIG. 4 is a view similar to FIG. 3 with the separator disc in the position it occupies substantially at the time the bottom signature is engaged by the jaws on the transfer drum;

FIG. 5 is a front elevational view of the apparatus;

FIC. 6 is a fragmentary side elevational view on an enlarged scale taken substantially as indicated along the line 66 of FIG. 3;

FIG. 7 is a view similar to FIG. 6 but taken along the line 7-7 of FIG. 4;

FIG. 8 is a top plan view of the separator disc and adaptor for jaw formed signatures;

FIG. 9 is a sectional view taken substantially as indicated along the line 99 of FIG. 8;

FIG. 10 is a fragmentary view similar to FIG. 8 illustrating the jaw formed signature adapter removed from the separator disc;

FIG. 11 is a fragmentary perspective view on an enlarged scale illustrating the jaw formed signature adapter;

FIG. 12 is a fragmentary sectional view taken substantially as indicated along the line l2l2 of FIG. 11;

FIG. 13 is a top plan view of the adapter for former board signatures;

FIG. 14 is a fragmentary top plan view of the separator disc with the former board signature adapter mounted thereon and the position of a stack of signatures illustrated in dot-dash lines so as to show the relationship between the separator disc and the signatures in substantially the same way as illustrated in FIG. 7 for the disc with the jaw formed signature adapter;

FIG. 15 is a section on an enlarged scale taken substantially as indicated along the line 15-15 of FIG. 13 with the separator disc illustrated in dot-dash lines;

FIG. 16 is a fragmentary sectional view taken substantially as indicated along the line 16-16 of FIG. 13; and

FIG. 17 is a view similar to FIG. 14 but illustrating the separator disc and former board signature adapter immediately prior to penetration of the signature stack by the separator disc.

DETAILED DESCRIPTION OF THE INVENTION For the general structure of the gathering machine, and the drive for the series of individual boxes, or stations thereof, reference is made to US. Pat. No. 2,621,039. Referring to the drawings of the present application in greater detail, and referring first to FIGS. 1, 2, and 5, a base frame, indicated generally at 20, which includes an upright rear support 21, a central support 22 and a forward support 23 connected by a horizontal web 24, a platform 25 surrounding the

upright support

21 and 22, and a line of forwardly extending webs 26 which support the gatherer means, indicated generally at 27. The latter means include a horizontal signature supporting panel 28a and an inclined signature supporting panel 28b which support gathered signatures S as they are moved along the machine by a gatherer chain, indicated generally at 29. The gatherer structure 27 extends continuously along beneath a series of signature boxes, or stations, such as the station indicated generally at 30 in FIGS. 1, 2 and 5.

Each of the stations 30 includes a pedestal base 31 on which is supported an upstanding hollow housing 32. A hearing sleeve 33 extends through the housing from its rear to its front and has an integral external flange 34 which bears against the rear of the housing and a bracket plate 35 embraces the forward portion of the sleeve 33 and is secured to the front of the hollow housing 32 by bolts 36. I

Signature transfer drum means, indicated generally at 37, includes a transfer drum 38 which is seen in FIG. 5 to be keyed to a shaft 39 that is journalled in the sleeve 33. At the rear of the shaft 39 is an enlarged hub 40 carrying a sprocket 41 by means of which the shaft 39 and drum 38 are rotated through a drive chain 42 which corresponds to the chain 221 illustrated in FIGS. 18 and 19 of 11.5. Pat. No. 2,621,039.

The signature transfer drum 38 is provided with two sets of signature gripping transferjaws 43 which are cyclicly opened and closed by cams as described in detail in US. Pat. No. 2,621,039. The gathering station 30 also includes mechanical sensing means, indicated generally at 44, which corresponds precisely to the detecting means H of US. Pat. No. 2,621,039 and which is cam operated in the same way.

A signature supply hopper, indicated generally at 45, includes a signature supporting platform 46, a forward signature confining assembly, indicated generally at 47, having a fore and aft movable carrier bar 48 provided with upright posts 49 for signature confining pads 50. A fixed rear signature guide 51 is positioned opposite the confining pads so that a stack of signatures S, the outline of which is indicated by broken lines in FIG. 2, is confined between the pads 50 and the guide 51. A fixed guide plate 52 is mounted upon a bracket 53 in position to be contacted by the leading ends of signature S in hopper 45 which form an exposed side of the stack, and an adjustable signature confining plate 54 is adjacent the trailing ends of the signatures in the hopper. The above described signature supply hopper 45 differs only in detail from that in the US. Pat. No. 2,621,039.

Suction separator means, indicated generally at 55, includes a pair of suction separator heads 56 carried on a tube 57 which forms a T connection with a fore and aft extending tube 58 that is journalled in pillow blocks 59 and 60 so that it may be rocked to raise and lower the suction heads 56. In order to rock the tube 58 it is provided with an arm 61 that is connected to a vertical push rod 62 which is cam actuated in a manner generally similar to that disclosed for the suction separator means B of US. Pat. No. 2,621,039.

As heretofore described, the apparatus is either identical with that disclosed in US. Pat. No. 2,621,039 or mechanically modified in accordance with commercial signature flatwise gathering machines manufactured and sold by the Sheridan Company, assignor of US. Pat. No. 2,621,039. The novel structure of the present invention is that which is hereinafter described in detail.

Surmounting the hollow housing 32 is a generally rectangular open frame 63 at the forward end of which is a split clamp 64 having a clamping bolt 65 to fixedly secure an upstanding stud 66. .lournalled on the stud 66 is a separator disc assembly, indicated generally at '67, and fixedly secured to the top of the disc assembly 67 is a drive pulley 68. Also mounted in the rectangular open frame 63 is a gear box 69 having an upright output shaft 70 provided with a pulley 71, and a drive belt 72 is trained around the

pulleys

68 and 71. The gear box 69 also has an input shaft 73 which is connected by a coupling 74 with a shaft 75 that is journalled in a bearing block 76 mounted on the rear end of the open frame 63; and the shaft 75 projects rearwardly to fixedly receive a sprocket 77.

Mounted on the hub 40 which carries the drive sprocket 41 for the transfer drum 38 is a separator drive sprocket 78, and a drive chain 79 which is trained around the sprocket 78'and the sprocket 77 A bracket 80 mounted on the outer end of the open frame 63 adjustably supports a stub shaft 81 on which is journalled a tensioning sprocket 82 for the drive chain 79.

Referring now particularly to FIGS. 3, 4 and 6 to 12, the disc separator assembly 67 includes a mounting element 83 and an adaptor element 84 which is best seen in FIGS. 8 to 11 to be secured to a relatively thin fastening flange 85 on the mounting element 83 by means of machine screws 86, which impale a mounting flange 87 on the adaptor element and fastening flange 85. The total thickness of the mounting flange and the fastening flange is seen to equal the thickness of the mounting element 83.

As best seen in FIGS. 3 and 4, the mounting element 83 includes a body portion 88, the radius of which from an axial hole 89 is greater than the distance from the hole and the stud 66 to the leading edge L of a signature S in the supply hopper 45. At the side opposite the area 88, the mounting element has a clearance portion 90 of substantially smaller diameter which is seen in FIGv 3 to clear the leading edge L ofa signature. As indicated by the arrow in FIG. 3, the separator disc assembly 67 rotates clockwise, and the fastening flange 85 occupies the rim of the trailing part of the clearance portion 90. As best seen in FIGS. 9 and 12, the periphery of the body portion 88 immediately trailing the clearance portion 90 is provided with a downwardly projecting bottom cam lug portion 91 and an upwardly projecting top cam lug portion 92 which overlies the portion 91. The leading ends of the

cam lug portion

91 and 92 are contiguous with a radially extending face 93 which constitutes the leading end of the body portion 88 and the line of demarcation between that portion and the clearance portion 90. The face 93 is seen in FIG. 12 to include a lower portion 94 which is perpendicular to the top surface of the body portion 88, and to also include a surface 95 which is inclined rearwardly in a trailing direction and occupies approximately one-half the thickness of the body portion and extends to the top surface of the top cam lug portion 92. As seen in FIGS. 8 and 9, the top and bottom

cam lug portions

91 and 92 have inclined trailing ends 91a and 92a, respectively.

The adapter element 84 includes a body portion 96 which has the mounting flange 87 along its inner edge portion, and the body portion 96 has a leading edge which is radial across the width of the mounting flange and which then has a leading face 97 at a negative rake angle. Along the periphery of the adapter element 84 are a bottom cam lug 98 and a top cam lug 99; and the trailing end of the adapter element 84 has surfaces complementary to the

surfaces

94 and 95 at the leading end of the mounting element body portion 88.

As best seen in FIGS. 9, 11 and 12, the bottom cam lug 98 includes a circumferential outer surface 100 which is inclined radially inwardly at about a 45 angle, and the bottom cam lug has an inclined leading surface 101 which is at an angle between about 25 and 30 to the horizontal and margins which diverge from a rounded nose 102 circumferentially to a maximum radial width 103 from which it tapers in an area 104 to the inner edge of the inclined outer surface 100. Thus, the inclined leading surface 101 is of generally an elongated diamond shape with a rounded nose and a long tapering trailing end. The top cam lug 99 is best seen in FIG. 12 to have an inclined leading surface 105 which forms an angle of about to the horizontal and trails the inclined leading surface 101 of thebottom cam lug by a short distance.

The

cam lug portions

91 and 92 of the mounting element 83 provide uninterrupted continuations of the bottom and top cam lugs 98 and 99, respectively.

A comparison of FIGS. 2 and 4 shows that a chord from the rounded nose 102 of the bottom cam lug 98 to the inclined trailing surfaces 91a and 92a of the

cam lug portions

91 and 92 is longer than the width of the transfer drum 38.

In operation, the suction members 56 and the cam separator disc 67 operate in timed relationship with the rotation of the transfer drum 38 as follows. The suction tube 58 is pivoted to swing the suction heads 56 upwardly into contact with the corner portion C of the lowermost signature S1 as seen in FIG. 6, and suction is simultaneously applied so that when the suction heads 56 are rocked downwardly to the position of FIG. 7 they will bend down the corner area C of the bottom signature S1. This occurs as the cam separator disc asembly 67 is approaching the position of FIGS. 2 and 3, so that the rounded nose 102 of the adapter element 84 may penetrate the stack of signatures S in the hopper between the bottom signature S1 and the next higher signature S2. As the cam disc assembly 67 rotates to the position of FIG. 4, it bends down the entire leading edge portion of the bottom signature S1 to a position where it may be gripped by the jaws 43 on the transfer drum 38 which withdraws the bottom signature S1 from the stack in the hopper and transfers it to the gathering assembly 27 where it is associated with other signatures S from other feeding stations 30 and carried along by the chain means 29. As the bottom cam lug 98-91 bends down the bottom signature S1 the top cam lug 99-92 supports and slightly lifts the signature S2 and all those above it so as to relieve weight on the signature S1 and facilitate its removal from the hopper by the transfer drum jaws 43.

6 The adapter element 84 seen in FIGS. 2 to 12 is of the type which is adapted for use with jaw formed signatures that have an open leading end and a closed side margin. Accordingly, the periphery of the adapter ele-' ment 84 forms an arc of a circle about the axis of the disc separator 67, and the rounded nose 102 is thus positioned to penetrate the side margin of the stack of signatures as seen in FIG. 3. Ifit penetrated the open leading end, it might penetrate between the pages of the signature and thus cause a malfunction of the apparatus by presenting only a part of the signature to the jaws 43.

Referring now to FIGS. 13 to 17, the mounting element 83 is illustrated in conjunction with an adapter element 184 which is constructed for use with signatures which have been folded on a former board. As previously indicated, such signatures have a closed leading end and an open margin; so that a separator disc must penetrate the stack between the bottom signature and thenext signature at the leading end L rather than at a side margin.

In order to accomplish this, the adapter element 184, which has a mounting flange 187 for attachment to the fastening flange of the mounting element 83, has a periphery which is an arc of a circle about the axis of the separator disc from its trailing end to the point p in FIG. 17; and from that point to a rounded leading end 202 the periphery 184a of the adapter element 184 is an arc of constantly decreasing radius. A leading surface 197 of the adapter element 184 is quite short and concavely curved with respect to the direction of rotation ofthe disc, and whereas the adapter element 84 has a leading surface 97 which is perpendicular to the plane of the disc, the leading surface 197 slopes in a trailing direction with a. slightly convex curve.

The adapter element 184 has a bottom cam lug 198 and a top cam lug 199 which are generally similar to those of the adapter element 84, but which taper inwardly toward the rounded nose 202 because of the constantly descreasing radius of the peripheral surface area 184a of the adapter element 184. Likewise, because of the blunter shape of the rounded nose 202 as compared with the rounded nose 102, an inclined leading surface 201 of the bottom cam lug 198 is more of a tear drop shape than'an elongated diamond.

Like the adapter element 84, the adapter element 184 has its bottom cam lug 198 provided with a circumferential outer surface which is inclined radially inwardly about 45, and the inclined leading surface 201 of the bottom cam lug is at an angle between about 25 and 30 to the horizontal. Likewise, the top cam lug 199 has a leading surface 205 which is inclined to the horizontal at an angle of about 20 and which trails the inclined leading surface of the bottom cam lug by a short distance.

In use, the separator disc equipped with the adapter element 184 cooperates with the suction separator cups 56 and the transfer drum jaws 43 in the same way as does the disc equipped with the adapter element 84. The only difference is in the fact that the adapter element 184 penetrates the stack from the leading end L instead of from a side margin.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. In a signature gathering machine of the type which has a line of signature supply hoppers each containing signatures stacked adjacent one another with their edges forming an exposed side of the stack, conveyor means adapted to receive and accumulate signatures from said hoppers, signature transfer means operatively associated with each hopper to deliver successive endmost signatures from the forward end of the stack to the conveyor, and suction means to bend a corner of the exposed edge portion of the endmost signature in the stack forwardly away from the balance of the stack to provide a gap, improved separator means for penetrating the gap to deflect the bent away edge portion of the endmost signature into the transfer means for separation from the stack comprising, in combination:

a shaft adjacent and parallel to the exposed side of the stack of signatures;

means for rotating said shaft;

and a transverse separator disc on said shaft which occupies a plane immediately forward of and parallel to the forward end of the stack,

said disc having a body with generally planar front and rear faces, said body having a radially narrow clearance portion which clears the exposed side of the stack and the circumferential extent of which is great enough-that the disc is clear of the stack during a part of each revolution,'said body also having a radially extended transversely arcuate separator portion which trails the clearance portion as the disc rotates and penetrates the gap behind the forwardly bent corner of the endmost signature,

said separator portion including a peripheral circumferential front cam lug which projects forwardly from the planar front face and has an inclined leading surface,

and a peripheral circumferential rear cam lug which projects rearwardly from the planar rear face generally in register with the front cam lug and has an inclined leading surface which joins that of the front cam lug along a rounded nose, so that the leading end of the separator portion is generally wedge shaped in cross section and extends forwardly and rearwardly from the plane of the disc, said cam lugs wedging between the bent endmost signature and the balance of the stack to deflect the bent away edge portion of the endmost signature into the transfer means and substantially simultaneously move the forward portion of the balance of the stack toward the rear to relieve pressure at the endmost signature.

2. The combination of claim 1 in which the front cam lug includes a circumferential outer surface which is inclined radially inwardly at about 45, and in which the inclined leading surface of said front cam lug is at an angle between about 25 and 30 to the plane of the body and has margins which diverge from a rounded nose circumferentially to a maximum radial width from which it tapers to the inner edge of said inclined outer surface. 1

3. The combination of claim 2 in which the inclined leading surface of the rear cam lug trails the inclined leading surface of the front cam lug by a short distance.

4; The combination of claim 3 in which the inclined leading surface of the rear cam lug is at an angle of about 20 to the plane of the body.

5. The combination of claim 1 in which the separator disc comprises a mounting element axially carried on the shaft, said mounting element including the entire clearance portion and having trailing parts of each of the lugs integral therewith, and there being a fastening flange extending from the trailing end of the clearance portion to the vicinity of said integral lug parts, and an adapter element detachably secured to said flange, said adapter element having the leading parts of both lugs formed thereon, said leading lug parts and said trailing lug parts being continuous.

6. The combination of claim 5 in which the leading end of the adapter element is shaped and positioned to penetrate the gap from a side margin of the endmost signature 7. The combination of claim 1 in which the leading ends of the lugs are shaped and positioned to penetrate the gap from a side margin of the endmost signature.

8. The combination of claim 7 in which the front cam lug includes a circumferential outer surface which is inclined radially inwardly at about 45, and in which the inclined leading surface of said front cam lug is at an angle between about 25 and 30 to the plane of the body and has margins which diverge from a rounded nose circumferentially to a maximum radial width from which it tapers to the inner edge of said inclined outer surface.

9. The combination of claim 1 in which the leading ends of the lugs are shaped and positioned to penetrate the gap from the leading edge of the endmost signature.

Claims

1. In a signature gathering machine of the type which has a line of signature supply hoppers each containing signatures stacked adjacent one another with their edges forming an exposed side of the stack, conveyor means adapted to receive and accumulate signatures from said hoppers, signature transfer means operatively associated with each hopper to deliver successive endmost signatures from the forward end of the stack to the conveyor, and suction means to bend a corner of the exposed edge portion of the endmost signature in the stack forwardly away from the balance of the stack to provide a gap, improved separator means for penetrating the gap to deflect the bent away edge portion of the endmost signature into the transfer means for separation from the stack comprising, in combination: a shaft adjacent and parallel to the exposed side of the stack of signatures; means for rotating said shaft; and a transverse separator disc on said shaft which occupies a plane immediately forward of and parallel to the forward end of the stack, said disc having a body with generally planar front and rear faces, said body having a radially narrow clearance portion which clears the exposed side of the stack and the circumferential extent of which is great enough that the disc is clear of the stack during a part of each revolution, said body also having a radially extended transversely arcuate separator portion which trails the clearance portion as the disc rotates and penetrates the gap behind the forwardly bent corner of the endmost signature, said separator portion including a peripheral circumferential front cam lug which projects forwardly from the planar front face and has an inclined leading surface, and a peripheral circumferential rear cam lug which projects rearwardly from the planar rear face generally in register with the front cam lug and has an inclined leading surface which joins that of the front cam lug along a rounded nose, so that the leading end of the separator portion is generally wedge shaped in cross section and extends forwardly and rearwardly from the plane of the disc, said cam lugs wedging between the bent endmost signature and the balance of the stack to deflect the bent away edge portion of the endmost signature into the transfer means and substantially sImultaneously move the forward portion of the balance of the stack toward the rear to relieve pressure at the endmost signature.

2. The combination of claim 1 in which the front cam lug includes a circumferential outer surface which is inclined radially inwardly at about 45*, and in which the inclined leading surface of said front cam lug is at an angle between about 25* and 30* to the plane of the body and has margins which diverge from a rounded nose circumferentially to a maximum radial width from which it tapers to the inner edge of said inclined outer surface.

4. The combination of claim 3 in which the inclined leading surface of the rear cam lug is at an angle of about 20* to the plane of the body.

6. The combination of claim 5 in which the leading end of the adapter element is shaped and positioned to penetrate the gap from a side margin of the endmost signature.

7. The combination of claim 1 in which the leading ends of the lugs are shaped and positioned to penetrate the gap from a side margin of the endmost signature.

8. The combination of claim 7 in which the front cam lug includes a circumferential outer surface which is inclined radially inwardly at about 45*, and in which the inclined leading surface of said front cam lug is at an angle between about 25* and 30* to the plane of the body and has margins which diverge from a rounded nose circumferentially to a maximum radial width from which it tapers to the inner edge of said inclined outer surface.