US3174375A - Cutter having a clamping bar attached to the cutting blade with a lost-motion connection - Google Patents

Description

March 23, 1965 D. P. WESTRA 3,174,375

CUTTER HAVING A DAMPING BAR ATTACHED TO THE v CUTTING BLADE WITH A LOST-MOTION CONNECTION Filed Aug. 19, 196.3 2 Sheets-Sheet.)

FIG. I.

Ami/14 March 23, 1965 n. P. WESTRA 4 7 CUTTER HAVING A DAMPING BAR ATTACHED TO THE CUTTING BLADE WITH A LOST-MOTION CONNECTION Filed Aug. 19, 1963 2 Sheets-Sheet 2 H I l B -I 76 l iv? 2N z E'lgQ 70 64 E O' 6o 2 22 i 5 J0 I E 2 F L I LHB'I E INVENTOR.

2O FAN 2 11/557764 H0. 3 BY M United States Patent "ice CUTTER HAVING A CLAMPING BAR ATTACHED TO THE CUTTING BLADE WlTH A LUST-MO- TIGN CCNNECTHCN Dan P. Westra, Grand Haven, Micln, assignor to The Challenge Machinery Company, Grand Haven, Mich, a corporation of Michigan 7 Filed Aug. 19, 1963, Ser. No. 303,007 1 Claim. (Cl. 83-384) This invention relates to a paper cutter apparatus, and more particularly to a simplified, compact paper cutter having no rigid side frames or overhead cross beams, and employing a cooperative cutter blade and clamping bar assembly operable with a simplified single drive means.

Paper cutting mechanisms capable of severing a substantial thickness of material conventionally employ large, rigid, east side frames to guide and support the reciprocating blades, and an overhead beam between the upper ends of the side frames. The blade is reciprocated vertically by a heavy crank assembly to obtain a force sufficient for slicing vertically through the material. A special clamp is ordinarily suspended from the frame adjacent the blade and has its own power means for actuation to hold the paper during the cutting. This conventional equipment is excessively heavy and large. Also, independent power assemblies are usually necessary for the clamp and the knife.

It is therefore an object of this invention to provide a simplified paper cutter having no rigid side frames or overhead cross beams. The cutter blade is completely supported, guided and reciprocated by a relatively simple pair of reciprocal pull down rods extending through the table.

It is another object of this invention to provide a paper cutter wherein both the blade and the clamping bar are operated by the same drive mechanism, with functioning thereof being automatically achieved sequentially using a lost motion connection therebetween. The cutter has an effective diagonal cutting action after the clamp contacts the material, with this diagonal action causing the clamp to tightly retain the material and causing an effective slicing action during the cutting.

It is another object of this invention to provide a simplified reciprocal screw-drive mechanism for the interconnected cutter blade and clamping bar, and to provide a reciprocating mechanism that eliminates the hydraulics, eccentrics, fly wheels, crankshaft and gears normally used. The sequential clamping and cutting action are automatically achieved from this same screw-drive mechanism, with reverse action of the blade readying the apparatus for the next cut. No additional guide motor or apparatus is necessary or employed for the clamping bar. The clamping always acts in proper timing with the blade.

These and several other objects of this invention will be apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a perspective view of the front of the novel cutter apparatus;

. FIG. 2 is a perspective view of the rear and one side of the novel apparatus in FIG. 1;

FIG. 3 is an enlarged elevational View of the novel cutter apparatus; and

FIG. 4 is a perspective view of the top of the cutting apparatus.

Referring specifically to the drawings, the novel cutting apparatus is supported on a table 12 which is mounted on a plurality of legs 16. Positioned above and generally across the top surface of the table 12 is an assembly 18 of the cutter blade 28 and clamping bar 36.

3,174,375 Patented Mar. 23, 1965 Mounted beneath the table platform is a reciprocal power drive mechanism 20. Connected between the cutter blade and the reciprocal power driving means 20 is a pair of pull-down rods or plungers 22. The rods extend vertically through opposite side edges of the table 12 through suitable openings machined into the table and forming bearing surfaces for the rods.

The cutter blade 28 is mounted to the upper ends of the plunger rods 22. The blade is positioned in elongated slots machined into the upper ends of the rods across the diameter thereof. The ends of the blade have elongated horizontal slots 30. Connecting pins 32 extend through the upper ends of the rods 22 through the slots 30. The pins also extend through vertical guide plates 34 on the opposite sides of tie bars 22. These plates serve as guide means for the clamping bar 36. The clamping bar 36 is positioned alongside the knife 28, and is not connected to tie bars 22. It includes a pair of end flanges 38 (FIG. 4) fitting within the vertical guide slots between cutter blade 28 and vertical guide plates 34.

The clamping bar 36 is attached to the cutter blade 28 by bolts or pins 40 which extend through respective ones of a pair of diagonal slots 42 in clamp 36 and holes in blade 28.

The clamping bar normally protrudes below the lower edge 28 of the blade 28 as shown in FIG. 3. The weight of the clamping bar 36 normally maintains the bolts or pins 40 at the upper ends of slots 42.

The lower ends of the respective plunger rods 22 are interconnected by a cross tie or beam having collars on its ends to fit around the lower threaded ends of rods 22. Oversized nuts 52 or the equivalent are screwed onto the ends of the rods 22. Mounted to the center of this beam 50 is a ball screw collar 54. A plurality of balls move in a closed circut on a helical path within the ball screw nut and through a diagonal bypass passage 56 extending from the upper end of the ball screw nut to the lower end. The ball screw nut surrounds a screw shaft 60 having a helical threaded for cooperation with the series of balls in the nut. The upper end of the screw shaft (60') is rotationally mounted in a radial bearing 62 and two thrust bearings 64 and 65. It is also operably keyed to a driven pulley 66.

The screw shaft is operably mounted in a support bracket which retains the radial and thrust bearings. The upper end of the shaft is secured in position by a pair of nuts 72 or the like. The ears 76 of bracket 70 are bolted to the underside of the table with bolts 78. The depending peripheral flange of table 12 is shown cutaway in FIG. 3 to illustrate this mounting.

Driven pulley 66 is rotated by a drive belt 80, also extending around a drive pulley 82. Pulley 82 is operably mounted on shaft 84 ,of an electric motor 86. The motor is mounted on plate bracket 87 affixed to a cross beam 89 between two of the legs 16. A motor brake 85 (FIG. 2) is provided around the shaft of the motor to stop the shaft rapidly when actuated. The brake includes a solenoid actuated brake shoe for this purpose.

Downward movement of the blade 36 is controlled by contact of the blade with the plunger of a first limit switch 81 mounted to the table. Upward movement of the blade and clamp is controlled by a second limit switch 83 attached by bracket 79 to a leg 16 of the table. This limit switch 83 is contacted by the cross beam 50. The upper limit switch 81 is operably connected to the power leads (not shown) and to reversible electrical motor 86 to cause the motor to reverse and raise the cutter apparatus when the switch is actuated. It also actuates the solenoid brake to stop the drive apparatus instantly thereby preventing over-riding of the blade and allowing quick reversal for rapid performance. Actuation of limit switch a o 83 opens the power circuit to stop the mechanism in the raised position.

Operation To cut a stack of paper 90 (FIG. 4) or equivalent material with the novel device, the stack is placed beneath the cutter blade and clamping bar when the assembly is in the raised position. The reversible motor 36 is then actuated with suitable safety switch means (not shown) to drive pulley 82, belt 80, pulley 66, and thereby rotate the screw shaft 60. Rotation of screw shaft 60 causes lowering of ball screw nut 55 and cross beam 50, to thereby lower the pull-down plunger rods 22. The sliding contact of the plunger rods with the table platform provides guide means preventing rotation of this apparatus with the ball screw shaft.

Lowering of the upper ends of the plunger rods causes knife 28 and clamping bar 36 to move vertically downwardly simultaneously until the clamping bar 36 tightly contacts material 90. Upon abutting and clamping the material to be cut, the clamping bar can move no further with the continuously moving cutting blade. Further lowering of the pull-down plunger rods 22 applies a downward force on the blade so that its pins 40 must follow the diagonal tracks or slots 42 in the clamping bar. The cutter blade therefore then moves in a diagonal manner to apply a slicing action across the paper, and not merely a chopping action in a vertical direction. This action also causes a force sufiicient on the clamping bar to press the clamping bar tightly against the material being cut.

The blade, in its travel, moves generally as shown by the phantom lines on the right-hand end of the apparatus illustrated in FIG. 3. That is, the lower edge 28' of the blade first moves directly downwardly to position 28a, where the clamping bar contacts the material, and then diagonally downwardly and laterally through the positions 28b, 28c, and down to 28d, where the cutting action is complete with the blade edge adjacent the table top. Limit switch 81 is then abutted by blade 28 to electrically apply brake 85 and stop the motor shaft, and then electricaly reverse the motor and raise the apparatus.

During this cutting action, the pins 32 mounting the blade to the tie bars move in a strictly vertical path. The horizontal slots 30 move over the pins as the blades shift laterally. The entire support, guiding and power re; ciprocation of the blade and clamping bar are thus achieved with the pair of vertically extending pull-down rods, with no additional side frames or overhead beams being necessary. The laterally and downwardly diagonal movement of the blade facilitates optimum cutting. Moreover, this clamp and blade action is achieved with this relatively simple but effective drive apparatus. Sequential timing of the blade and clamp are always in proper relationsihp since the blade automatically begins cutting as soon as the clamp has the material firmly in position.

Reversal, i.e. lifting of the mechanism is had by reversing the electric motor 86 as mentioned, to operate the screw drive assembly in reverse. This raises the apparatus to a position for another cut. As the pull-down rods move upwardly to lift the blade, the weight of the clamp bar causes it to fall with respect to the blade until the pins 40 are at the upper ends of the diagonal slots 42 and the pins 32 are at the right ends of the slots 30 as viewed in FIG. 3.

The novel apparatus is exceptionally lightweight, low in overall height, and assumes only a relatively small amount of floor space. It is efiicient and effective, requiring only one power source and drive mechanism. The parts operate sequentially, and automatically in the proper relationship. The components are readily manufactured and assembled. Operation is simple, even though automatic. Various additional advantages will occur to those in the art upon studying the foregoing specification and drawings. A complete listing of such is deemed unnecessary. Also, various obvious structural modifications employing the inventive concepts herein taught will be readily apparent to those skilled in the art. These obvious modifications are therefore deemed to be part of this invention.

Iclaim:

A paper cutter, comprising: a support table having a bed; a pair of pull-down shaft members mounted in bearings extending through said table bed near opposite sides of said table bed for vertical movement with respect to said table bed; a beam connecting the lower ends of said shaft members beneath said table bed; motor drive means between said beam and the bottom of said table to vertically raise and lower said beam and shaft members; said shaft members each having their top ends free with vertical slots therein aligned with each other in a lateral direction across said bed; a cutter blade extending above and across the top of said table, having its ends seated in said slots; detachable means for detachably mounting said cutter blade on said shaft members; said shaft members serving as the sole support means and guide means for said cutter blade, said shaft members in combination with said motor means and beam constituting and reciprocal drive means for said cutter blade; said blade having horizontal slots on its ends; said detachable means including first pins removably secured to said members and extending through said slots of said shaft members and said horizontal slots of said blade to form a lateral lost-motion connection between said blade and members; a clamping bar mounted solely to the side of said blade and having a lower paper contacting surface; said bar having diagonal slots; clamping bar support pins extending through said blade and said diagonal slots to form the sole mounting connection between said blade and said bar to suspend said bar on said blade; separate guide means on the ends of each of said shaft members for guiding said bar for vertical movement with respect to said blade; said clamping bar support pins, said diagonal slots, and said guide means allowing said paper contacting surface of said bar to normally be slightly below the blade cutting edge; said blade and bar initially being lowered vertically together by lowering of said beam and pull-down shaft members by means of said motor drive means to draw said blade down, and only said blade being diagonally lowered after pressing contact of said bar surface with paper to be cut; said blade and bar being easily removable by removing first said pins and lifting said blade and bar upwardly from said shaft slots and guide means.

References Cited by the Examiner UNITED STATES PATENTS 10/62 Great Britain.

ANDREW R. J UHASZ, Primary Examiner.

WILLIAM W. DYER, Examiner. A

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