US3375939A - Papercutter - Google Patents

Description

April 2, 1968' L; D. BARLEY PAPERCUTTER 2 Sheets-Sheet 1 Filed Jan. 28, 1966 INVENTOR.

LEO D. BARLEY ATTORNEYS A ril 2, 1968 L. D. BARLEY 3,375,939

PAPERCUTTER Filed Jan. 28, 1966 2 Sheets-Sheet L FIG-4 44 7-,-

United States Patent Ofiice 3,375,939 Patented Apr. 2, 1968 Filed Jan. 28, 1966, Ser. No. 523,754 Claims. (Cl. 2141.6)

This invention relates to an improved back gage for use with large papercutters, and to novel means to maintain back gage alignment and to absorb the shocks produced when the back gage initially engages a pile of paper.

In large papercutters or trimmers, a pile of sheet material is normally first placed on a work table and a movable back gage is brought into engagement against the pile. The back gage and the pile are then moved to position the pile beneath a cutting knife where it may be clamped prior to cutting. The back gage may then move the pile forward to a new position Where the cutting process may be repeated. Accurate cutting of the pile is assured only if the back gage, and particularly its face which engages a pile, is maintained in proper alignment with the table and with the plane of the cutter.

Proper alignment of the back gage may readily be maintained if the back gage is kept free from any disturbing shocks or uneven sudden loading conditions which may affect the back gage support and drive mechanism, but in modern high speed papercutters, the back gage can be moved under some conditions at fairly high speed. Thus, should the operator cause a large and heavy pile to be located such that the back gage engages the pile while the pile may not be centered or setting squarely on the table, back gage alignment could be seriously affected. Not only can the alignment of the back gage with respect to the knife be affected, but, in some installations the calibration of the back gage position indicator may be disturbed, and also the back gage control mechanism may not thereafter track properly.

The present invention is directed to a shock absorbing device mounted on the front face back gage to avoid misalignment of the back gage due to shocks and forces produced when the back gage engages a heavy pile of paper. This shock absorbing mechanism consists of a spring loaded face plate mounted on the forward part of the back gage mechanism and adapted to engage the pile. The springs are preloaded such that the face plate will not yield relative to the back gage due merely to the friction of the pile when moving the heaviest pile of paper normally encountered on the papercutter, but which may yield when the back gage initially engages a heavy pile to minimize the shock on the back gage drive and to preserve alignment and to avoid damage to the drive mechanism.

A novel form of back gage drive mechanism is also provided which is mechanically more rigid and less likely to be misaligned than the prior art drive mechanisms. This drive mechanism includes a guide block rigidly attached to the back gage and which eliminates any adjustable mechanisms between the back gage and the lead screw which were formerly used in squaring the back gage with respect to the cutting knife.

Accordingly, it is an object of this invention to provide a shock absorbing back gage mechanism for trimming or cutting machines, which protects the back gage and drive mechanism from damage and misalignment when the back gage is moved into engagement with a pile of paper and which will remain in alignment when moving such a pile of paper across the table.

It is a further object of this invention to provide a novel back gage shock absorbing mechanism which is adapted to yield when initially engaging a pile of paper and which may be preloaded to yield to forces sufficient to cause misalignment of the back gage but which will not yield under normal operating conditions. In addition, the back gage may be provided with a dampening mechanism to prevent the recoil of the pile of paper after deflection of the shock absorbing mechanism.

It is a further object of this invention to provide a novel back gage shock absorbing mechanism. where the back gage will remain in alignment with the paper cutting table and with the plane of the cutting knife notwithstanding the sudden engagement of the back gage with a heavy load of paper thus to assure proper tracking of magnetic control devices and proper calibration of the back gage position indicator.

It is a further object of this invention to provide a sturdy and rigid back gage drive mechanism which is permanently aligned with the plane of the cutting knife and which is protected from misalignment due to shocks caused by the sudden engagement of the back gage with a pile of material to be cut.

These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a side elevational view of a typical papercutter employing the shock absorbing back gage mechanism of this invention, with the side gage partly broken away for illustration;

FIG. 2. is a pictorial view of the back gage and part of the machine table, showing a portion of the back gage position indicating and control mechanism;

FIG. 3 is a plan view of the back gage illustrating the location of the adjustable back gage supporting members;

FIG. 4 is a cross sectional view taken along line 4-4 in FIG. 3;

FIGS is a cross sectional view taken. along line 5-5 in FIG. 3;

FIG. 6 is an enlarged plan view of the left hand portion of the back gage with some of the parts broken away to show the details of its construction;

FIG. 7 is a cross sectional view taken along line 77 in FIG. 6;

FIG. 8 shows one modification of the adjustable back gage supporting members; and

FIG. 9 shows one modification of the adjustable back gage retaining bolts.

Referring to the drawings, which show a preferred embodiment of this invention, and particularly to FIGS. 1 and 2, a papercutter is shown provided with a table 10 onto which may be placed a pile of paper to be cut. A back gage 12 is movable along the table and is adapted to engage the pile of paper and push it into position under the knife 14 mounted in holder 15. Immediately prior to cutting, the paper may be held against movement by clamp member 16. The extent of the sideward movement of the paper is limited by a side gage 18 mounted on both sides of the table 10. The side gage 18 in FIG. 1 is shown partially cut away to allow a full view of the back gage.

The position of the back gage may be determined by the operator from the front of the machine by observing the indicia on a metal tape 20 reeved on pulleys 21 and 22 and driven by the back gage through the upstanding arm 23. Power to move the back gage is supplied by a motor 27 which rotates a lead screw 28 through a clutch mechanism generally indicated at 29. The lead screw may also be rotated by hand from the front of the machine by turning handle 30. Surrounding the lead screw 28 and in driving engagement therewith is a driving nut 32 which is securely attached to the back gage mechanism through a slot 33 in the table 10.

A control mechanism may also be provided to automatically position the back gage at preselected locations with respect to the cutting knife so that a series of cuts may be made on the pile of paper. In one application, the control mechanism consists of a magnetic drum 35 extending along the length of the back gage above the table 10. This magnetic drum may have marks magnetically placed thereon which may be detected by a pair of magnetic pickup members 36 mounted on an amplifier box 37 secured to the back gage 12. The magnetic pic-kup heads 36 are spring biased against the magnetic drum 35 and slide along the drum to sense the position and occurrence of the magnetic control mark. This magnetic drum may contain more than one set of back gage position control information, and the particular set of control information in use may be determined by rotating a selector knob 40 on the front of the machine which, through appropriate gearing, will rotate the shaft 41 and the magnetic drum 35. A more complete description of the magnetic control of the back gage may be found in United States Patent 'No. 3,195,385, issued July 20, 1965.

The back gage alignment with reference to the table 10 and to the plane through which the cutting knife 14 moves must be accurately maintained to insure that the paper will be cut properly and accurately. In addition, proper back gage alignment is necessary to insure accurate calibration of the indicating tape 33' and proper tracking of the magnetic pickup heads 36 along the magnetic control drum 35. Proper alignment is assured in the present invention by providing a rigid and more rugged back gage drive mechanism and also by providing a shock absorbing means on the paper engaging portion of the back gage to absorb the shocks and possible unequal loading effects which may occur when the back gage initially engages a heavy pile of paper at high speed or when the operator slams the paper against the gage in an attempt to square the pile.

The back gage 12 is supported on the table 10 by a set of adjustable supporting members 44 threaded into the opening 45 in the extended horizontal portion of back gage 12. These adjustable members may be formed from a metallic bolt member 46 having a wrench fitting at its upper end and a threaded nylon portion 47 secured to the bolt 46 at the upper end and in sliding engagement with the table 10 at its lower end. A locking nut 48 is also provided to prevent rotation of the plugs once they are properly adjusted. A gage '50 is also permanently available adjacent each nylon supporting member to insure proper clearance and leveling of the back gage 12 with respect to table 10. This gage comprises a metallic depth pin 50 having a length accurately determined so that the upper surface 51 of the pin will be flush with the adjacent surface of the back gage 12 when the pin is in engagement with the table 10 and the proper clearance of about .003 inch, indicated at 52, exists between the lowermost portion of the back gage 12 and the table 10.

An alternative embodiment of the back gage supporting member 44' is shown in FIG. 8. In this embodiment a nylon plug 55 is inserted into the opening 45 in the back gage and a threaded metallic adjustment screw 56 is threaded through the upper portion of the back gage. The screw '56 is also provided with an opening 57 adapted to receive an Allen wrench while a locking nut 58 prevents rotation once the plug is properly adjusted.

The back gage drive mechanism includes a back gage guide block 60 positioned beneath the table 10 and in 4 driving engagement .with the lead screw 28. As shown in FIG. 4, a boss extends from the guide block 60 and includes the driving nut 32 which is securely held in position by the clamping bolt 61. A ta-per pin 62 is also provided to prevent rotation of the nut 32.

The table 10 is provided with a downwardly projecting tongue member 65 having a machined surface 66 accurately finished square to the plane of the cutting knife 14. In addition, the tongue 65 has a portion 67 machined to be parallel with the surface 66 and therefore also square to the plane of the cutting knife. The surface 70 of the guide block 60 is also finished flat so that it is in sliding engagement with the surface 66 on the tongue 65. A gib 71 engages the surface 67 on the tongue and may be adjustably pressed against the surface by several bolts 72, only one of which is shown in FIG. 4. A depression in the gib 67 under each bolt 72 serves to keep the gib from sliding with respect to the guide block 60. Thus, the back gage guide block 60 is guided by the tongue portion 65 on the table 10 and insures that the guide block 60 will remain square to the plane of the cutting knife 14 throughout its length of travel.

A portion 74 of the guide block 60 extends upwardly through the slot 33 in the table 10 into the keyway 75 defined in the downwardly extending projections 76 on the back gage 12. A pair of bolts 77 extend through the back gage 12 and into the guide block 60 to hold these two members in clamping engagement. The back gage therefore is securely mounted to the guide block 60 and keyway 75 will remain square with the plane of the cutting knife 14.

Shims may be positioned between the upper surface of the upwardly extending portion 74 of the guide block 60 and the keyway 75 in the guide block. In addition, an adjustment, which may include gib blocks 78 and a set of adjusting screws 79, may be provided between the lowermost portion of the tongue 65 and the guide block 74. The inclusion of these modifications will in large part be dictated by the tolerances specified in machining the various component par-ts of the drive and guide mechanism.

With the main portion of the back gage 12 therefore aligned with the plane of the cutting knife 14 and with the table 10, proper tracking of the magnetic pickup heads 36 along the magnetic drum 35 is thus assured as well as the accuracy of the tape indicator 20. In the prior art paper cutting devices using an adjustable coupling means between the drive mechanism and the back gage, misalignment was possible which could cause failure of the magnetic pickup heads to sense the control marks due to excessive spacing as well as misalignment of the back gage position indicator. With the drive mechanism herein described, however, these problems are eliminated.

Protection of the back gage and the back gage driving mechanism from uneven loading and sudden forces due to the engagement of the back gage with a heavy pile of paper may be provided by the shock absorbing mechanism shown particularly in FIGS. 6 and 7. The shock absorbing mechanism comprises a yielding face plate 80 having a front portion adapted to engage a pile of papers 81. The back gage 12 has an L-shaped throat portion 82 at its forward part provided with a sliding surface 83 adapted to be in sliding engagement with the inwardly extending member 84 of the plate 80. A set of springs 86 are positioned between the plate 80 and the upstanding portion 82 of the back gage and are maintained in compression by a set of bolts 88. In the preferred embodiment of this invention four pairs of coil springs 86 are evenly spaced across the back gage between the paper engaging plate 80 and the portion 82 on the back gage.

As shown in FIG. 5, the bolt 88 extends through a boss 89 on the face plate 80 and may be secured in place by a locking nut 90. An extended portion of the bolt extends through the upstanding portion 82 of the back gate 12 and has threaded onto its end an adjusting nut 91 and locking nut 92. The bolts 88 are adjusted to preload the springs 86 so that they will not be deflected by the normal frictional forces which must be overcome in order to move the heaviest pile of paper 81 across the table into position under the knife 14 and clamp 17. On the other hand, the springs are adjusted so that they may yield and absorb the shocks created when the back gage is moved initially against a pile of paper 81. Suflicient clearance is provided between the plate 80 and the back gage to prevent actual contact of these two members. The amount of clearance is dictated by the stiffness and the number of the springs 86.

To prevent a recoil of the pile of paper 81 away from the plate 80 when the back gage is initially moved against the pile, a dampening mechanism 95 is provided which allows the plate 80 to move toward the back gage freely, being restrained only by the springs 86, but which will cause the plate slowly to return to its normal position as determined by the position of the nut 91 at such a rate that the paper will not be thrown away from the face plate 80. Since it is common in some paper cutters to have an air bearing between the pile of paper 81 and the table 10, such a recoil could impede the smooth and speedy operation of the machine.

As shown in FIG. 3, the center bolt 88 is normally used to preload the springs to the desired degree while the bolts 88 at each end may be used to make minor adjustments in the alignment of the plate 80 with respect to the plane of the cutting knife 14 and thereby achieve absolute parallelism.

One modification of the bolt means used to limit the travel of plate 80 with respect to the upstanding member 82 on the back gage and to preload the springs 86 is shown in FIG. 9. A stud member 96 is threaded into the boss 89, and a bolt 97 extends through the front surface of the plate 80 and is threaded in the stud 96. A hexagonal portion 98 facilitates assembly by providing a wrench engaging surface. An adjusting nut 91 and a locking nut 92 are placed on the portion of the stud extending through member 82.

A shock absorbing back gage has therefore been described which is useful especially on large scale paper cutters and which is provided with a guide block and drive mechanism especially adapted to hold the back gage in alignment with the plane of the cutting knife and which includes a shock absorbing face plate on the back gage to absorb any shocks which may be transmitted through the back gage to the drive mechanism and which would otherwise tend to create a misalignment or damage to the machine.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A cutting apparatus comprising a table for supporting a pile of sheet material to be cut, cutting means mounted above said table, a back gage movable on said table and adapted to position said pile under said cutting means, drive means mounted beneath said table for moving said back gage, said table being provided with a slot in the direction of the back gage movement, guide block means extending through said slot and fixed to said back gage, cooperating means on said table in sliding engagement with said guide block means for maintaining said back gage in alignment with said table, said guide block means further being in driving engagement with said drive means for movement of said back gage, and yielding means mounted on the forward portion of said back gage for deflecting and absorbing the impact when the back gage is initially engaged with a pile and which will remain undeflected when said pile is being moved normally across the table.

2. The apparatus as defined in claim 1 wherein said yielding means includes a plate adapted to engage said pile, spring means positioned between said plate and the forward portion of said back gage, and means to preload said spring means so that the plate will not be deflected relative to said back gage when a pile is being moved normally by said back gage but which may deflect and absorb the impact when the back gage is. initially engaged with said pile thereby to minimize the shocks transmitted to the back gage and associated drive means.

3. The apparatus as defined in claim 2 wherein said means to preload said spring means includes a bolt member attached to said plate and extending through a portion of said back gage and arranged to place said spring means in compression thereby requiring a force exceeding the amount of the preloading to cause further compression of said spring means and consequent yielding of said plate.

4. The apparatus as defined in claim 1 wherein said back gage comprises a horizontal member provided with a plurality of adjustable support means in sliding engagement with said table for determining the clearance between the back gage and the table, a throat portion at the forward part of said back gage, a plate mounted for limited movement in said throat portion adapted to engage said pile, a plurality of springs positioned between said plate and said throat portion, and adjustable means to preload said springs so that said plate will yield to forces which exceed that required to move the heaviest anticipated pile of sheet material.

5. The apparatus as defined in claim 1 wherein said yielding means includes a plate having a forward portion adapted to engage said pile, a throat portion at the forward part of the back gage adapted to receive in sliding engagement a portion of said plate, spring means positioned between said plate and said throat portion, and means to preload said spring means so that said plate will yield to forces which exceed that required to move the heaviest pile across said table, and dampening means positioned between said plate and said throat portion for restraining the rapid return of the plate to its normal position after being deflected by the engagement of a pile while permitting unrestrained compression of said springs during initial deflection of said plate.

6. The apparatus as defined in claim 1 wherein said yielding means includes a plate having a front portion adapted to engage said pile, spring means positioned between said plate and the forward portion of said back gage, means to preload said spring means such that the plate will not be deflected relative to said back gage when a pile is being moved normally by said. back gage but which may deflect and absorb the impact when the back gage is initially engaged with said pile thereby to minimize the shocks transmitted to the back gage and the associated drive means, and adjusting means for aligning said plate parallel to the plane of said cutting means.

7. The apparatus as defined in claim 6 wherein said means to preload said spring means includes a first bolt member attached to said plate and extending through a portion of said back gage and arranged to place said spring means in compression thereby requiring a force exceeding the amount of the preloading to cause further compression of said spring means and consequent yielding of said plate, and at least one other bolt member attached to said plate and extending through a portion of said back gage at a position remote from said first bolt member and adjustable to align the pile engaging portion of said plate parallel to the plane of said cutting means.

8. The apparatus as defined in claim 6 wherein said adjusting means includes a pair of bolt members attached to said plate at substantially each end thereof, said bolt members extending through a portion of said back gage and adjustable to align the pile engaging portion of said plate parallel to the plane of said cutting means.

9. The apparatus as defined in claim 1 wherein said back gage comprises a horizontal member provided with a throat portion at the forward part thereof, a plate mounted for limited movement in said throat portion adapted to engage said pile, a plurality of springs positioned between said pile and said throat portion, adjustable means to preload said springs such that the plate Will yield to forces Which exceed that required to move the heaviest anticipated pile, and adjusting means attached to said plate to align the pile engaging portion of said plate parallel to the plane of said cutting means.

10. The apparatus as defined in claim 9 wherein said adjusting means includes a bolt member attached to said '8 plate at substantially each end thereof, said bolt members each extending through Said throat portion of said back gage and adjustable to align the pile engaging portion of said plate parallel to the plane of said cutting means.

References Cited UNITED STATES PATENTS 3,032,209 5/1962 Mead 214l.6

GERALD M. FORLENZA, Primary Examiner.

F. E. WERNER, Assistant Examiner.

Claims (1)

1. A CUTTING APPARATUS COMPRISING A TABLE FOR SUPPORTING A PILE OF SHEET MATERIAL TO BE CUT, CUTTING MEANS MOUNTED ABOVE SAID TABLE, A BACK GAGE MOVABLE ON SAID TABLE AND ADAPTED TO POSITION SAID PILE UNDER SAID CUTTING MEANS, DRIVE MEANS MOUNTED BENEATH SAID TABLE FOR MOVING SAID BACK GAGE, SAID TABLE BEING PROVIDED WITH A SLOT IN THE DIRECTION OF THE BACK GAGE MOVEMENT, GUIDE BLOCK MEANS EXTENDING THROUGH SAID SLOT AND FIXED TO SAID BACK GAGE, COOPERATING MEANS ON SAID TABLE IN SLIDING ENGAGEMENT WITH SAID GUIDE BLOCK MEANS FOR MAINTAINING SAID BACK GAGE IN ALIGNMENT WITH SAID TABLE, SAID GUIDE BLOCK MEANS FURTHER BEING IN DRIVING ENGAGEMENT WITH SAID DRIVE MEANS FOR MOVEMENT OF SAID BACK GAGE, AND YIELDING MEANS MOUNTED ON THE FORWARD PORTION OF SAID BACK GAGE FOR DEFLECTING AND ABSORBING THE IMPACT WHEN THE BACK GAGE IS INITIALLY ENGAGED WITH A PILE AND WHICH WILL REMAIN UNDEFLECTED WHEN SAID PILE IS BEING MOVED NORMALLY ACROSS THE TABLE.

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