US3224367A

US3224367A - Marking mechanism for use with sheet material

Info

Publication number: US3224367A
Application number: US235393A
Authority: US
Inventors: Norman K Henkel
Original assignee: Harris Intertype Corp
Current assignee: Harris Graphics Corp
Priority date: 1962-11-05
Filing date: 1962-11-05
Publication date: 1965-12-21
Anticipated expiration: 1982-12-21

Description

Dec. 21, 1965 N. K. HENKEL MARKING MECHANISM FOR USE WITH SHEET MATERIAL Filed Nov. 5, 1962 2 Sheets-Sheet 1 III III! i :1" ll INVENTOR.

Noe/m4 K HEN/(EL g E ATTUPNE Ya Dec. 21, 1965 N; K. HENKEL 3,224,367

MARKING MECHANISM FOR USE WITH SHEET MATERIAL Filed Nov. 5, 1962 2 Sheets-Sheet 2 %Q @I I I I I I I I I I I I I I I I 4 y I I I I i ,h

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III I I I I I g I I I It I I II E2 1 I I I l I H INVENTOR. NORMANKHENKEL Arronwsvs II II IIIIII FI'I BY United States Patent 3,224,367 MARKING MECHANISM FOR USE WITH SHEET MATERIAL Norman K. Henkel, Dayton, Ohio, assignor to Harris- Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed Nov. 5, 1962, Ser. No. 235,393 Claims. (Cl. 101-226) The present invention relates to a device for marking matter conveyed relative thereto, and particularly, to a device for use in association with a printing press for marking or impressing a line, such as a tear line, on sheetlike material in sheet or web form as it is delivered from the press.

In books of printed items such as receipts, tickets, checks, and the like, it is common practice to provide a single sheet comprising a plurality of printed items, such as checks, which are detachable from other items, such as other checks and check stubs, upon tearing along tear lines formed in or marked on the sheet and outlining the item to be detached. These sheets are normally printed by a printing press with a plurality thereof on each length of sheet material printed, and the sheets are often provided with spaced, continuous, transverse tear lines extending between opposite edges of the sheet material and transverse to the direction of movement of the sheet ma terial through the press, and broken, longitudinal tear lines, that is tear lines having spaced areas breaking the lines, extending parallel to the direction of movement of the sheet material through the press and intersecting the transverse tear lines. These spaced areas are provided in the sheet material where tearing is not desired such as between check stubs to remain in the book.

An important object of the present invention is the provision of a new and improved, simple, and reliable mark ing mechanism having a marking element movable periodically into and out of marking position and which is constructed to provide ready adjustment to change the frequency and period between movements of the marking element.

A further object of the present invention is the provision of a new and improved marking mechanism having marking means and means for actuating movement of the marking means in sequence out of and then into engage ment with sheet material in timed relation to the feed of the sheet material relative thereto including a first trip means operable to actuate the movement of the marking means into engagement with the sheet material and a second trip means operable to actuate movement of the marking means out of engagement with the sheet material, and wherein one of the trip means is readily adjustable relative to the other to adjust the length of marking.

A further object of the present invention is the provision of a new and improved marking mechanism as noted in the next preceding paragraph, wherein said first and second trip means comprise cam elements and the cam elements are adjustably secured to a cam wheel and the position of the cam elements on the cam wheel can be easily changed.

A further object of the present invention is the provision of a new and improved marking mechanism wherein a marking means is moved periodically into and out of engagement with the sheet material in timed relation to the feed of the sheet material relative thereto by trip means capable of being adjusted to change the timing of the movements of the marking means and is retained in the position to which it is moved by means constructed and arranged to minimize bouncing of the marking element relative to the sheet material and undesired skipping by the marking element.

3,224,367 Patented Dec. 21, 1965 A further object of the present invention is the provision of a new and improved marking mechanism, as noted in the next preceding paragraph, wherein the aforementioned trip means includes cam elements operable to periodically move the marking means into and out of engagement with the sheet material and the positions of the cam elements and the number thereof being readily variable to change the frequency of and period between movements of the marking means.

Further objects and advantages of the present invention will be apparent to those skilled in the art to which it relates from the following details description thereof made with reference to the accompanying drawing, in which:

FIG. 1 is a side elevational view of an apparatus embodying the present invention;

FIG. 2 is a vertical sectional view taken approximately on the section line 22 of FIG. 1;

FIG. 3 is a perspective view of a portion of the apparatus illustrated in FIG. 1;

FIG. 4 is a vertical sectional view taken approximately on the section line 44 of FIG. 2; and

FIG. 5 is a partial sectional plan view of the apparatus shown in FIG. 1 taken approximately on the section line 5-5 of FIG. 1.

The preferred and illustrated embodiment of the present invention is shown by way of example as embodied in a rotary printing press having spaced side frame members 10 and 11. An impression cylinder 12, a feed cylinder 12', and a plate cylinder 13 extend between the side frame member 10 and 11 and are rotatably supported thereby. A conventional numbering mechanism is also supported by the side frame members 10, 11 at 14. Preferably the numbering mechanism comprises a plurality of numbering heads mounted on a rotating support.

Sheet material to be printed is conveyed by the feed cylinder 12' to the impression cylinder 12 which carries the material through the print line between the numbering mechanism and the impression cylinder 12 and then between the plate cylinder 13 and the impression cylinder 12. After the sheet material passes beyond the plate cylinder 13 it is marked along a longitudinal line by one or more suitable marking mechanisms 15 which form longitudinal tear lines on the sheet material extending parallel to the direction of movement of the sheet material. The material is then transferred to a suitable delivery mechanism including a delivery cylinder 16 supported on delivery cylinder shaft 16 and is delivered from the press.

The marking mechanisms 15 may be of any general type, for example, line markers, scoring mechanisms, slitters, or perforators. The marking mechanisms 15 here shown are perforating devices each having a marking element or perforating wheel 20 cooperating with the impression cylinder 12 to form a series of narrow, aligned slits or identations in the sheet material as it moves past the marking mechanism to provide a perforated tear line therein. The perforating wheels 20 may, if desired, be moved in unison toward and away from the impression cylinder 12 to move the wheels into and out of engagement with-the sheet material in timed relation to the advance of the sheet material to provide breaks, i.e, unperforated portions, in the line f identati-ons formed thereby.

The perforating wheels 20 are moved into and out of engagement with the sheet material by trip means including trip or

cam elements

22, 23 which actuate movement of the perforating wheels 20 into and out of engagement with the sheet material, respectively. The

cams

22, 23 operate in timed relation to the feed of the sheet material through the press, and are adjustably mounted on a movable support or cam wheel 26 which in turn is mounted on the delivery cylinder shaft 16' and rotates with the shaft in timed relation 'to the advance of the sheet material.

The

cams

22, 23 are, in the illustrated embodiment, adjustably secured to opposite sides of the cam wheel 26 by bolts 28, 29, respectively. Each of the bolts 28, 29 extends through an arcuate slot in the cam which it secures to the cam wheel and into one of the numerous bolt holes 30 provided in the cam wheel 26 for receiving the bolts 28, 29. The cams are adjustable relative to their respective bolts, and for example, the bolt 28 may be loosened and cam 22 may be moved relative to the bolt through the provision of the slot in the cam 22, thereby providing a fine adjustment of the cam on the cam wheel 26. It should be apparent that the position of the

cams

22, 23 may be changed on the cam wheel 26 by removing the bolts 28, 29 from the bolt holes 30 in which they are located and inserting them in different bolt holes 30. The positions of the

cams

22, 23 may be changed to change the timing of the operation thereof relative to each other and to the advance of the sheet material to thereby change the ending and starting points for the markings formed thereby and the length of the markings on the sheet material.

The

cams

22, 23 have portions 22a, 23a, respectively, extending beyond the periphery of the cam wheel 26, and which are operable to actuate movement of the perforating wheels 20 in sequence out of and then into engagement with the sheet material upon one revolution of the cam wheel 26, as will be apparent from the description below. A plurality of cams may be supported on each side of the cam wheel 26 so as to actuate movement of the perforating wheels 20 into and out of engagement with the sheet material a plurality of times during one revolution of the cam wheel 26.

As the cam wheel 26 rotates, the

cams

22, 23 alternately actuate cam follower levers 32, 34, respectively, which are fixedly secured to a shaft 36, rotatably mounted in side frame member 11. The cam follower levers 32, 34 extend from shaft 36 in different directions and their ends remote from shaft '36 are positioned adjacent the periphery of cam wheel 26 and are provided with roller means 37, 38, respectively, positioned in the path of movement of cam portions 22a, 23a. The roller means 37, 38 are adapted to be engaged by the cam portions 22a, 23a, respectively, upon rotation of the

earns

22, 23 with the cam wheel 26. Engagement of the cam portion 22a with the roller means 37 causes the shaft 36 to be rotated in a clockwise direction as viewed in FIG. 1, while engagement of cam portion 23a with roller means 38 causes the shaft 36 to be rotated in a counterclockwise direction, as viewed in FIG. 1.

A lever 40 is fixedly secured at the end of the shaft 36 opposite the end on which the cam follower levers 32, 34 are mounted and oscillates between its full line and dotted line positions upon rotation of the shaft 36. The end of the lever 40 opposite the end secured to the shaft 36 is provided with a roller 41 mounted thereon. The roller 41 constantly engages a surface 42 of a hook-like portion 43 of a latch member 44 supported for pivotal movement by side frame member 11 and biased in a clockwise direction as viewed in FIG. 1 into engagement with the roller 41 by spring means 44'. The spring 44 is secured at one end to a pin 45 secured to shaft 36 and coaxial therewith and secured at the other end to a pin 45a secured to member 44.

The surface 42 of hook-like portion 43 which is biased into engagement with roller 41 includes a pair of recesses 46, 48 separated by a fiat 49 for a purpose to be described hereinbelow. The recesses 46, 48 are constructed to receive the roller 41 upon movement of the roller 41 with lever 40. When roller 41 is moved by actuation of lever 32 by cam 22 -it is received in recess 46 and when roller 41 is moved by actuation of lever '34 by cam 23 it is received in recess 48.

When the lever 40 is in its dot-dash position shown in FIG. 1, roller 41 is positioned in recess 48 and spring 44 holds the latch member 44 in its extreme position rotated in a clockwise direction. Movement of the lever 40 to its full line position as shown in FIG. 1 from its dot-dash position by the cam 22 causes the roller 41 to move into the recess 46 in the member 44 and causes the latch member 44 to rotate relative to the side frame member 11 in a counterclockwise direction against the bias of spring 44'. When in its full line position shown in FIG. 1 the lever 40 functions as a stop or blocking member and prevents rotation of the latch member 44 in a clockwise direction. The latch member 44 is moved in a clockwise direction by the spring 44 upon release of the lever 40 by the cam 23. The lever 40 is released, that is, moved from its full line position to its dot-dash position as shown in FIG. 1 by cam 23 and this movement allows the bias of spring 44 to rotate the latch member 44 in a clockwise direction to its extreme clockwise position. The recess 48 is deeper than the recess 46 to provide for this movement.

The recesses 46, 48 are constructed to permit free pivotal movement of the lever '40 and also provide for securely holding the roller 41 mounted on the end of the lever 40 therein to provide two stable positions therefor. The biasing force of the spring 44' and the shape of the recesses 46, 48 function to hold the roller 41 in the recess in which it is positioned. It can be seen therefore that the surface of the latch member 44 defining the recesses 46, 48 and the surface of the roller 41 are cooperating locking portions having a locking relationship when the roller 41 is in its two positions located in the respective recesses. The flat 49 which separates the recesses 46, 48 lies in a plane tangent with the bottom of recess 46 and permits pivotal movement of the lever 40 from the fullline position in FIG. 1 to its dot-dash position without effecting any substantial increment of movement of the latch member 44 in a counterclockwise direction, as viewed in FIG. 1, which is the direction to cause the perforating wheels to move toward the sheet material.

The member 44 is fixedly secured on a stub shaft 58 rotatably mounted in the side frame 11 of the press. The stub shaft 58 is provided with a tongue 59 on one end thereof which cooperates with a groove 59 on the end of a bar 60 on which the perforating mechanisms are mounted. Rotation of the latch member 44 causes the stub shaft 58 to rotate and the bar 60 on which the perforating devices are mounted is rotated therewith through the tongue and groove 59, 59'. Upon rotation of the bar 60 on which the perforating mechanisms are mounted the perforating wheels 20 are moved into or out of engagement with the sheet material depending upon the direction of rotation of the bar 60 on which they are mounted.

The perforating devices mounted on the bar 60 include bifurcated support arms 62 extending from a support block or unit 64 which has a rectangular shaped opening 66 therethrough. The support bar 60 for the perforating mechanisms has a generally rectangular cross section and extends through the openings 66 in the support units 64 and supports each support unit thereon. The bar 60 for the perforating devices is suitably threaded and lock

nuts

70, 72 threadedly engage the opposite sides of the support block 64 and each block 64 may be moved longitudinally along the bar 60 by turning the

lock nuts

70, 72 associated with it along the bar 60 in the direction in which it is desired to move the block 64. Each support block 64 is provided with suitable setscrew means for fixedly securing the support block 64 in position on the bar 60 so that the position of each perforating wheel 20 relative to the sheet material may be changed and the distance from the edge of the sheet material at which the tear lines are formed by the perforating wheels may be varied.

The bar 60 with the perforating devices mounted thereon may be readily and easily snapped into or out of position between the frame members 10 and 11 of the printing press. The left end of the bar 60, as shown in FIG. 2, is provided with a tapered opening 74 which serves as a hearing when the bar 60 is assembled in the press, as will be fully described hereinbelow. The opening 74 cooperates with a correspondingly tapered male latch member 76 slidably mounted in a passageway 77 in the frame member and biased in a direction towards the frame member 11 by a coil spring 78.

The bar 60 can be positioned between the frame members 10 and 11 of the press by placing the tapered end of tapered latch member 76 in the opening 74 in the left end of the bar member 60 and overcoming the bias of the spring 78 by forcing the bar member 60 towards the left, aligning the right end of the bar member 60 with the stub shaft 58, and then permitting the spring 78 to engage the tongue and groove 59, 59, causing the bar member 60 to be supported thereby on the right side and by the latch member 76 on the left side, as viewed in FIG. 2.

The operation of the structure disclosed herein should be apparent from the above description. The trip means or

cams

22, 23 constitute a control means moved in timed relation to the advance of the sheet material and control the position of the perforating wheels 20. The earns 22 and 23 rotate with the cam wheel 26 and the portions 22a and 23a thereof alternately engage

rollers

37 and 38, respectively, mounted on the

levers

32 and 34. Engagement of the roller 37 by the portion 22 of cam 22 causes the shaft 36 to be rotated in a clockwise direction as viewed in FIG. 1. The clockwise rotation of the shaft 36 moves the lever 40 from its dot-dash position shown in FIG. 1 to its full line position. Movement of the lever 40 to its full line position in FIG. 1 causes roller 41 to bear against surface 42 of member 44 and move into recess 46, which results in rotation of the member 44 in a counterclockwise direction, moving the perforating wheels into engagement with the sheet material. The perforating wheels are held in engagement with the sheet material by the bias of the spring 44' and the shape of the recess 46 in which the roller 41 is positioned and movement of the perforating wheels out of engagement with the sheet material is blocked by the lever 40. It can be seen from the above description that the mechanism actuated by the

cams

22, 23 including the lever 40 and latch member 44 constitutes an operating means for moving the perforating wheels into and out of engagement with the sheet material.

Upon engagement of the roller 38 by cam portion 23a of cam 23 the shaft 36 is rotated ina counterclockwise direction causing the lever 40 to be rotated in a counterclockwise direction as viewed in FIG. 1 from its full line position to its dot-dash position and the spring 44 rotates the member 44 in a clockwise direction, causing rotation of the bar 60 in a clockwise direction and movement of the perforating wheels 20 out of engagement with the sheet material. The perforating wheels 20 remain out of engage-ment with the sheet material until cam portion 22a again actuates movement thereof into engagement with the sheet as above described. From the above description it should be apparent that the

trip members

22, 23a actuate a bistable linkage

means including members

40 and 43 and the linkage means is maintained through selflocking in the position to which it is actuated by the trip members without the necessity of an outside force being applied thereto.

It should be understood that any number of perforating devices or marking devices may be supported on the support bar 60 corresponding to the number of longitudinal lines to be formed in the sheet material. Moreover, while the preferred embodiment of the present invention shows two earns 22, 23 mounted on the cam wheel 26 for moving the perforating wheel 20 into and out of engagement with the sheet material, respectively, any number of cams may be positioned on the cam wheel within limits prescribed by the structure itself, de pending upon the desired frequency of movement of the perforating wheels 20 into and out of engagement with the sheet material. The cams which actuate the lever 32 should be secured to the inner surface of the cam wheel while the cams which actuate lever 34 should be secured to the outer surface of the cam wheel.

While the

cams

22 and 23 are shown with a slope on each end it is obvious that only one slope is effective to engage and actuate the respective rollers. However, to simplify manufacturing, the earns 22 and 23 are made alike, and can fit on either side of the wheel 26. This permits use of one cam slope when a cam is used in the position of cam 22, and the other slope when the same cam is used in the position of cam 23.

Moreover, it should be understood that while the present invention has been-described above in considerable detail, modifications, changes and adaptations thereof may be made by one skilled in the art without departing from the scope of the appended claims.

Having described my invention, I claim:

1. In 'a device of the class described, marking means for marking on sheet material advanced relative thereto and movable periodically between active and inactive positions into and out of engagement with the sheet material, respectively, means supporting said marking means for movement between said active and inactive positions, operating means connected to said marking means to move said marking means between its said positions and including a member movable between first and second positions for effecting movement of said marking means between said inactive and active positions, a latch part operatively associated with said member and engag-cable therewith to releasably hold said member in its first and second positions, first and second trip means movable in timed relationship to the advance of said material and operatively connected to said member to force said member from said first position to said second position and from said second position to said first position, respectively, and means for changing the time of operation of one of said first and second trip means relative to the other, said latch part comprising a hook like part connected to said marking means for movement therewith, and said hook-like part includes a pair of recesses for receiving a portion of said member when said member is in its first and second position, respectively, and wherein said device further includes spring means biasing said hook-like part into engagement with said portion of said member and frictionally holds said member in the recesses.

2. A device according to claim 1 wherein said recesses are of different depths and are joined by a surface tangent to the bottom of the recess corresponding to the position in which said member is located when said marking mechanism is in its operative position.

3. In a printing press having printing cylinders about which sheet material is advanced, marking means for marking the sheet material as it is advanced about the printing cylinder, means supporting said marking means for movement between active and inactive positions in engagement with the sheet material and out of engagement with the sheet material, respectively, a latch member movable with said marking means, spring means biasing said latch member to move said latch member and said marking means out of engagement with said sheet material, a lever member having a portion engageable with said latch member to block movement of said latch member by said spring means, a shaft member supporting said lever member and rotatable in opposite directions to eflect pivoting movement of said lever memher in opposite directions relative to said latch memher, said latch member and the portion of said lever member engageable with said latch member being operatively associated so that movement of said lever member in a first direction causes said latch member to move under the bias of said spring and move said marking means to its said inactive position and movement of said lever member in a second direction opposite said first direction causes said lever member to force said latch member against the bias of said spring to effect movement of said marking means into its active position, said shaft carrying a pair of axially spaced cam follower members extending in angularly disposed relationship to said shaft, a cam wheel rotatable in timed relation to the advance of the sheet material, said cam wheel being provided with means for adjustably securing a plurality of cam elements on each side thereof, said cam wheel being positioned for rotation adjacent said cam follower members, first trip means secured on one side of said cam wheel and movable in a path containing one of said cam follower members and engageable therewith to effect rotation of said shaft in one direction, a second trip means secured on the other side of said cam wheel and movable in a path containing the other of said cam followers and engageable therewith to effect rotation of said shaft in said second direction whereby upon rotation of said cam wheel said trip means engages said cam followers to effect movement of said lever member in opposite directions to effect movement of said marking means into and out of engagement with said sheet material.

4. A marking device comprising marking means movable between an active position in engagement with sheet material to be marked to an inactive position out of engagement with the sheet material and operable to mark the sheet material when in engagement therewith, a latch part movable as a unit with the marking means, spring means biasing said latch part and said marking means to said inactive position, a stop member engageable with said latch part to limit movement thereof by said spring means and movable between first and second positions with respect to said latch part with movement of said stop member to its first position from its second position causing movement of said latch part against the bias of said spring means and movement of said marking means to its active position and movement of said stop member to its second position causing movement of said latch part by said spring means and movement of said marking means to its inactive position, said latch part and said stop member having cooperating locking portions having a locking relationship when said stop member is in its first and second positions, first trip means operable to force said stop member from its locking relationship with said latch part when in its second position and to its said first position, second trip means operable to force said stop member from its locking relationship with said latch part when in its first position and to its said second position, support means supporting said first and second trip means and movable in timed relation to the advance of the sheet material to move said trip means in timed relation to the advance of the sheet material to render said first and second trip means operative in sequence, and means for adjustably securing the first and second trip means to said support for changing the time of operation of one of said trip means relative to the other.

5. A marking device comprising marking means movable between an active position in engagement with sheet material to be marked to an inactive position out of engagement with the sheet material and operable to mark the sheet material when in engagement therewith, a latch part movable as a unit with the marking means, a member engageable with said latch part and movable between first and second positions with respect to said latch part with movement of said member to its first position from its second position causing movement of said latch part and said marking means to its active position and movement of said member to its second position causing movement of said latch part and movement of said marking means to its inactive position, said latch part and said member having cooperating locking portions having a locking relationship when said member is in its first and second positions, first trip means operable to force said member when in its sec- 'ond position from its locking relationship with said latch part and to its said first position, second trip means operable to force said member from its locking relationship with said la-tch part when in its first position and to its said second position, support means supporting said first and second trip means and movable in timed relation to the advance of the sheet material to render said first and second trip means operative in sequence, and means for adjustably securing the first and second trip means to said support to change the time of operation of one of said trip means relative to the other.

References Cited by the Examiner UNITED STATES PATENTS 184,208 11/1876 Hopping 7454 206,832 8/1878 Schroder et al. 7454 228,758 6/1880 Hobbs 7454 357,965 2/1887 Nesmith 83473 X 398,042 2/1889 Harrison 10l--226 651,828 6/1900 Copeland 7454 655,535 8/1900 Wells et al. 74568 852,375 4/1907 Carlton 83-332 X 1,620,512 3/1927 Bowigon 16140 1,831,660 ll/l931 Hancock 83470 X 2,240,790 5/1941 Kuney 16142 2,542,140 2/1951 Holm 292--79 2,699,372 l/l955 Mosler 10l269 2,859,999 11/1958 Anderson 292-336 2,903,145 9/1959 Brinkel 7454 X ROBERT E. PULFREY, Primary Examiner.

EUGENE R. CAPOZIO. Examiner.

Claims

1. IN A DEVICE OF THE CLASS DESCRIBED, MARKING MEANS FOR MARKNG ON SHEET MATERIAL ADVANCED RELATIVE THERETO AND MOVABLE PERIODICALLY BETWEEN ACTIVE AND INACTIVE POSITIONS INTO AND OUT OF ENGAGEMENT WITH THE SHEET MATERIAL, RESPECTIVELY, MEANS SUPPORTING SAID MARKING MEANS FOR MOVEMENT BETWEEN SAID ACTIVE AND INACTIVE POSITIONS, OPERATING MEANS CONNECTED TO SAID MARKING MEANS FOR MOVE SAID MARKING MEANS BETWEEN ITS SAID POSITIONS AND INCLUDING A MEMBER MOVABLE BETWEEN FIRST AND SECOND POSITIONS FOR EFFECTING MOVEMENT OF SAID MARKING MEANS BETWEEN SAID INACTIVE AND ACTIVE POSITIONS, A LATCH PART OPERATIVELY ASSOCIATED WITH SAID MEMBER AND ENGAGEABLE THEREWITH TO RELEASABLY HOLD SAID MEMBER IN ITS FIRST AND SECOND POSITIONS, FIRST AND SECOND TRIP MEANS MOVABLE IN TIMED RELATIONSHIP TO THE ADVANCE OF SAID MATERIAL AND OPERATIVELY CONNECTED TO SAID MEMBER TO FORCE SAID MEMBER FROM SAID FIRST POSITION TO SAID SECOND POSITION AND FROM SAID SECOND POSITION TO SAID FIRST POSITION, RESPECTIVELY, AND MEANS FOR CHANGING THE TIME OF OPERATION OF ONE OF SAID FIRST AND SECOND TRIP MEANS RELATIVE TO THE OTHER, SAID LATCH PART COMPRISING A HOOKLIKE PART CONNECTED TO SAID HOOK-LIKE PART INCLUDES A PAIR MENT THEREWITH, AND SAID HOOK-LIKE PART INCLUDES A PAIR OF RECESSES FOR RECEIVING A PORTION OF SAID MEMBER WHEN SAID MEMBER IS IN ITS FIRST AND SECOND POSITION, RESPECTIVELY, AND WHEREIN SAID DEVICE FURTHER INCLUDES SPRING MEANS BIASING SAID HOOK-LIKE PART INTO ENGAGEMENT WITH SAID PORTION OF SAID MEMBER AND FRICTIONALLY HOLDS SAID MEMBER IN THE RECESSES.