US3196725A - Punching apparatus having means to center workpiece - Google Patents

Description

July 27, 1965 c. K. HULEN 3,196,725

PUNCHING APPARATUS HAVING MEANS T0 CENTER WORKPIECE Filed Jan. 28, 1963 v 2 Sheets-Sheet 1 'INVENTOR. 614005 Z l/uusu A TTORIVEYS I PUNCHING APPARATUS HAVING MEANS T0 CENTER WORKPIECE Filed Jan. 28, 1963 C. K. HULEN July 27, 1965 2 Sheets-Sheet 2 CLAUDE Z ATTORNEYS United States Patent 3,196 725 PUNCHING APPARATUS HAVING MEANS T0 CENTER WORKPIECE Claude K. Hulen, 1524 Charlotte, Kansas City, Mo. Filed Jan. 23, 1963, Ser. No. 254,264 Claims. (Cl. 83-389) This invention relates to sheet punch apparatus, and more particularly to precision devices of this character suitable for use in the graphic arts, such as lithography and engraving.

The principal objects of the present invention are: to provide sheet punch apparatus having extremely high accuracy and repeatability; to provide such apparatus Wherein the sheet to be punched is automatically clamped in position immediately prior to punching in conjunction with punch motion; to provide such apparatus which includes anextremely simple but effective centering device which cooperates with a gauge or wall surface to accurately and quickly center and align a sheet for punching; to provide a precision machine of this type which prodnces clean, accurately spaced punch openings in a great variety of materials difficult to punch and which is easily maintained in sharp condition; to provide such apparatus which includes a translucent supporting table for eflicient viewing of sheet material being punched; and to provide such a unit which is simple and rugged in construction, portable, and easily used by relatively inexperienced personnel.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain embodiments of this invention.

FIG. 1 is a fragmentary plan view of punch apparatus embodying this invention.

FIG. 2 isa fragmentary perspective view on an enlarged scale of a portion of the punch apparatus, particularly showing the relationship between the punching and holdaiown mechanisms.

FIG. 3 is a fragmentary vertical cross-sectional view on an enlarged scale, particularly showing the hold-down mechanism in clamping position.

FIG. 4 is a fragmentary vertical cross-sectional view 0 an enlarged scale, particularly showing a punch and a hardened bushing which acts as a die.

FIG. 5 is a fragmentary perspective view on an enlarged scale, particularly illustrating a pulley forming a part of a sheet centering device.

FIG.- 6 is a fragmentary perspective view on a reduced scale illustrating a precision graphic step and repeat vacuum frame line-up table having an adjustable precision straight edge with spaced pegs for receiving a punched masking sheet. I

FIG. 7 is a fragmentary vertical sectional view on an enlarged scale illustrating the peening or belling of a punch piror to insertion into a die for maintaining sharpness.

Referring to the drawings in more detail:

The reference numeral 1 generally indicates a sheet punch apparatus embodying this invention. The apparatus 1 includes a horizontally extending sheet or work-supporting table 2 having a translucent cover 3 whereby the work may be illuminated from beneath for ease of viewing. A riser bar 4 is fixed to the table 2 and is positively positioned by means of suitable aligning pins 5. Bearing members 6 are spaced along the riser bar 4 and extend upwardly therefrom.

A shaft 7 extends parallel to the table 2 and is rotatably mounted in the bearing members 6. A suitable handle 7 has legs 8 secured to the shaft 7 with set screws 8' and extending laterally therefrom for selectively rotating the 3,195,?25 Patented July 27, 1965 "ice shaft 7 through an .arc for reasons apparent hereinafter. Coil springs 9 are engaged respectively with hearing membars 6 and collars 9' fixed to the shaft 7 for resiliently urging the shaft to a rotational position where the handle 7' is normally substantially elevated above the table 2.

A plurality of laterally extending punch heads 10 are rotatably fixed to the shaft 7 by means of set screws 11 extending into a longitudinally extending groove 12 in the shaft. The punch heads 10 are spaced along the shaft 7 and a plurality of vertically extending sleeve bearing receiving bores '13 are in the riser bar 4 aligned with the punch heads 10. Sleeve bearings 14 are supported in the bores 13 and a longitudinally slidable punch 15 is reciprocal in each of the sleeve bearings 14. Links 16 are pivotally connected at opposite ends thereof to the heads 10 and the upper ends 17 of the punches 15.

A cut-away portion 18 in the riser bar 4 forms a vertically extending rear wall surface 19 and facing, horizontally extending, spaced apart upper and lower Wall surfaces 20 and 21 defining a recessed forwardly open elongated horizontally extending slot 22 between the riser bar 4 and the table 2 for receiving sheets or work to be punched, as discussed hereinafter. The sleeve bearings 14 open at the lower ends thereof at the upper wall surface 2!) whereby the punches 15 may slide therefrom into the slot 22;

A plurality of receiving bores 23 extend vertically into the table 2 and are respectively aligned with the riser bar bores 13. Hardened bushings or dies 24 are received and supported in the table bores 23 and each has a die opening 25 therein opening at the lower wall stuface 21. The punches 15 are guided by the sleeve bearings 14 through the slot 22 into the die opening 25.

A plurality of laterally extending hold-down heads 26 are rotatably fixed to the shaft 7 by means of set screws 27 engaging the groove 12 and are spaced therealong intermediate respective punch heads 10. A plurality of vertically extending rod receiving bores 28 are located in the riser bar 4 and aligned with the hold-down heads 26. Vertically extending rods 29 are slidably received in the rod bores 28 and links 30 are pivotally connected to the rods at the upper ends 31 thereof.

An elongated upwardly extending recess 32 is located in each of the hold-down heads 26. A horizontally and norm-ally vertically extending slot 33 extends through each of the hold-down heads 26 and intersects the respective recesses 32. Pins 34 are received in the hold-down head slots 33 and are movable therein vertically (longitudinally) with respect to the recesses 32. A helical compression spring 35 is retained in each of the recesses 32 and resiliently bears against the pins 34 for urging same downwardly, the pins 34 pivotally connecting the links 30 to the hold-down heads 26.

The rods 29 at the lower ends 36 there-of are reduced in diameter forming shoulders 37. The ends 36 extend into the forwardly open slot 22. A hold-down bar 38 is located in the slot 22 and has a vertical height less than the spacing between the upper and lower wall surfaces forming the slot 22. Spaced vertical bores 38' extend through the bar 38 and receive the lower ends 36, securing the rods 29 to the bar 38 by means of set screws 39 for vertical reciprocation of the bar 38 in the slot 22. The shoulders 37 bear against the hold-down bar 38 to prevent downwardly relative motion of the rods 29 with respect to the bar 38. Bores or openings 40 of slightly greater diameter than the punches 15 extend vertically through the hold-down bar 38 for slidably receiving the lower ends of the punches 15 therethrough.

The punch heads 10 and hold-down heads 26 are rotatably fixed with respect to each other whereby the bar 38 resiliently engages against the sheet to be punched reams 3 or lower wall surface 21 before the punches engage in the die openings 25 upon moving the handle 7' through an arc toward the supporting table. Resiliency in the downward engagement of the hold-down bar 38 is furnished by the compression of the springs in response to movement of the pins 34 in the slots 33.

The dies or hardened bushings 24- open downwardly of the supporting table 2 and a removable catch tray 41 engaged in table grooves 42 is located directly beneath the hardened bushings for receiving die cuts therefrom.

A pair of parallel closely laterally spaced upwardly open slots 43 and 44 extend transversely across the supporting table 2 adjacent the riser bar 4 and in parallel relation with the rear wall surface 19. Pulleys 45, and 46 are located at opposite ends of the slots 43 and 44 and are mounted on the table 2 for rotation about respective vertical axes. A tape or ribbon 47 is engaged with the pulleys and 46 in a loop forming parallel legs 42; and 49 respectively located'in the upwardly open slots 43 and 44. A resilient helical tension spring St) is engaged with opposite ends of the tape or ribbon 47 drawing the tape or ribbon tightly against the pulleys 45 and 46.

Locating lugs 51 and 52 are longitudinally slidable respectively in the upwardly open slots 43 and 44 and are respectively engaged with the legs 48 and 49 of the tape or ribbon 47 by means of set screws 53 extending into lug slots 54 receiving the tape or ribbon. The lugs 51 and 52 are adjusted whereby they arrive at the exact center between the pulleys 45 and 46 at the same instant when moved toward each other, the tape or ribbon 47 insuring that the lugs move simultaneously over equal distances. Cover plates 55 and 56 are respectively located over one-halfof the upwardly open slots 43 and 44 and are flush with the surface of the table 2. The plates 55 and 56 prevent unnecessary interruption in the continuity of the table surface, but yet permit free sliding of the lugs 51 and 52 respectively over half the Width of the table 2.

In operation, a work piece such as a masking sheet 57 has the edge 53 to be punched urged into the slot 22 and against the rear wall surface 19. The lugs 51 and 52 are then urged toward each other and a portion 59 of the lugs which extends above the surface of the table 2 contacts lateral edges 60 and 61 of the sheet 57 centering the sheet on the table 2. With the lugs 51 and 52. and the rear wall surface 19 simultaneously contacting the masking sheet, the sheet is exactly and repeatably located with respect to the punches 15 and hardened bushings 24. By moving the handle 7' downwardly, the hold-down bar 38 contacts the upper surface of the masking sheet 57 and clamps same against the table 2 in the slot 22. Further downward motion of the handle 7' urges the punches 15 through the masking sheet, placing spaced punched holes 62 therein corresponding to the spacing of the punches 15. The punched out portions (not shown) fall into the catch tray 41 for convenient storage until removed for disposal. The masking sheet 57, in the illustrated example, may then be engaged with slightly upstanding pegs 63 suitably secured to a precision adjustable straight edge 64 of a stop and repeat line-up table 65 of the type often used in the graphic arts industry.

Due to the extreme precision possible with the abovedescribed apparatus, the masking sheet 57 or other Work (including, for example, zinc or aluminum metal printing plates) may be'exactly located in desired position on the line-up table 65. Subsequent sheets, when punched in the above-noted manner, will always bear an exact known relationship with the masking sheet 57 since the holes punched therein will be located with respect to the transverse center line between the lateral edges contacted by the lugs 51 and 52.

In order to maintain high precision, it is necessary that the punches 15 retain a sharp edge where contacting the hardened bushings 24. A convenient method for periodically insuring maximum sharpness comprises removing the catch tray 41 which exposes the bottom of the hardened bushing 24, and inserting upwardly therethrough a punch-like member 66 (FIG. 7) and driving same (peening) with a hammer or the like (not shown) against the bottom surface 67 of the punches 15. This causes the relatively soft metal. (compared to the bushings or dies 24) forming same to bell or enlarge to a slightly greater diameter. The punches are then pushed down against the hardened bushings so that a thin Wire edge (not shown) on the bottom of the punch will be removed and the result will be an accurate, positive fit of the lower end of the punch in the die bore.

In a typical punch apparatus embodying this invention, the punches are spaced apart approximately 4 inches, the spacing being held to a tolerance of less than .001 inch. Clean, accurate holes may be punched in a great variety of difiicult-to-cut sheet materials such'as tissues, vinyls, acetates and, as noted above, zinc or aluminum printing plates.

It is to be understood that while one form of this invention has been illustrated and described, it is not to be limited to the specific form or arrangement of parts herein described and shown except insofar as such limitations are included in the claims.

What I claim and desire to secure by Letters Patent is:

1. A sheet punching apparatus comprising:

(a) a sheet supporting table, a riser bar fixed With respect to said table and having spaced bearing members extending therefrom, a shaft rotatably mounted in said bearing members, means operably secured to said shaft for selectively rotating said shaft through an arc,

(b) punch guide means on said riser bar, a plurality of spaced punching members axially slidable in said punch guide means, one of said punching members being at a center position of a line parallel to said shaft, connecting means between each of said punching members and said shaft for sliding said punching members in response to the rotation of said shaft, means forming a recessed open slot adjacent said riser bar for receiving said punching members thereinto,

(c) means in said table forming a receiving bore with a die opening into said slot for each of said punching members and aligned with said respective punching members across said slot, said punching members being reciprocably guided through said slot into said receiving bores upon actuation of said shaft rotating means,

(d) rod guide means on said riser bar, a rod slidable in said rod guide means, i

(e) a head fixed to said shaft, a slot extending through said head and intersecting said recess,

(f) a pin in said head slot and movabletherein toward and away from said recess, a resilient member in said recess and resiliently bearing against said pin for urging same tranvsersely of said head slot,

(g) a link pivotally connected between said pin and said rod whereby said head, pin and link operatively connect said shaft and said rod for sliding said rod in response to the rotation of said shaft,

(h) a hold-down bar having a height less than the height of said slot, said hold-down bar being operably secured to said rod for reciprocation in said slot,

(i) resilient means between said hold-down bar and said shaft, whereby said hold-down bar resiliently engages a sheet in said slot before said punching members enter said receiving bore upon actuation of said shaft rotating means,

(j) and adjustable lug means equally and simultaneously movable toward and away from said center position and engageable with a sheet to be punched to center said one punching member relative to opposed edges of said sheet.

2. A sheet punching apparatus as set forth in claim 1 wherein the connecting means between each punching member and the shaft includes a head member on the shaft, a link having one end pivotally connected to the respective head member and the other end pivotally connected to the respective punching member, and means securing the head member to the shaft for sliding said punching member in response to rotation of said shaft.

3. A sheet punching apparatus as set forth in claim 2 wherein the punch receiving bores open through the supporting table with a hardened bushing in each of said punch receiving bores and having the die openings therein and a removable catch tray is engaged in the table for receiving die cuts from the sheets.

4. A sheet centering device for punching apparatus and the like having a sheet supporting table comprising:

(a) means forming a pair of parallel closely laterally spaced upwardly open slots extending transversely across said supporting table,

(b) a pulley located at opposite ends of said slots and mounted with respect to said table for rotation about axes perpendicular to said table,

(c) a tape engaged with said pulleys in a loop forming parallel legs respectively located in said slots, means for drawing said tape taut against said pulleys, and

(d) a locating lug slidable in each of said slots and engaged with said respective legs, a portion of said lugs extending above the surface of said table for simultaneously contacting opposite edges of a sheet, whereby the sheet is located on said table.

5. In combination with a sheet punching aparatus having a sheet supporting table and a sheet receiving punching slot with a rear locating wall surface:

(a) a pair of parallel closely laterally spaced upwardly open slots extending transversely across said supporting table in parallel relation with said rear wall surface,

(b) pulleys rotatably mounted at opposite ends of said upwardly open slots, a tape engaged with said pulleys in a loop forming parallel legs respectively located in said upwardly open slots, resilient means for drawing said tape taut against said pulleys, and

(c) a locating lug slidable in each of said upwardly open slots and engaged with said respective legs, a portion of said lugs extending above the surface of said table for simultaneously contacting opposite edges of sheets to be punched,

(d) whereby sheets to be punched are centered laterally and squared with respect to said punch apparatus prior to punching due to simultaneous engagement with said lugs and said rear wall surface.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS Germany.

WILLIAM W. DYER, 111., Primary Examiner.

ANDREW R. IUHASZ, Examiner.

Claims (1)

1. A SHEET PUNCHING APPARATUS COMPRISING: (A) A SHEET SUPPORTING TABLE, A RISER BAR FIXED WITH RESPECT TO SAID TABLE AND HAVING SPACED BEARING MEMBERS EXTENDING THEREFROM, A SHAFT ROTATABLY MOUNTED IN SAID BEARING MEMBERS, MEANS OPERABLY SECURED TO SAID SHAFT FOR SELECTIVELY ROTATING SAID SHAFT THROUGH AN ARC, (B) PUNCH GUIDE MEANS ON SAID RISER BAR, A PLURALITY OF SPACED PUNCHING MEMBERS AXIALLY SLIDABLE IN SAID PUNCH GUIDE MEANS, ONE OF SAID PUNCHING MEMBERS BEING AT A CENTER POSITION OF A LINE PARALLEL TO SAID SHAFT, CONNECTING MEANS BETWEEN EACH OF SAID PUNCHING MEMBERS AND SAID SHAFT FOR SLIDING SAID PUNCHING MEMBERS IN RESPONSE TO THE ROTATION OF SAID SHAFT, MEANS FORMING A RECESSED OPEN SLOT ADJACENT SAID RISER BAR FOR RECEIVING SAID PUNCHING MEMBERS THEREINTO, (C) MEANS IN SAID TABLE FORMING A RECEIVING BORE WITH A DIE OPENING INTO SAID SLOT FOR EACH OF SAID PUNCHING MEMBERS AND ALIGNED WITH SAID RESPECTIVE PUNCHING MEMBERS ACROSS SAID SLOT, SAID PUNCHING MEMBERS BEING RECIPROCABLY GUIDED THROUGH SAID SLOT INTO SAID RECEIVING BORES UPON ACTUATION OF SAID SHAFT ROTATING MEANS, (D) ROD GUIDE MEANS ON SAID RISER BAR, A ROD SLIDABLE IN SAID ROD GUIDE MEANS, (E) A HEAD FIXED TO SAID SHAFT, A SLOT EXTENDING THROUGH SAID HEAT AND INTERSECTING SAID RECESS, (F) A PIN IN SAID HEAD SLOT AND MOVABLE THEREIN TOWARD AND AWAY FROM SAID RECESS, A RESILIENT MEMBER IN SAID RECESS AND RESILIENTLY BEARING AGAINST PIN FOR URGING SAME TRANSVERSELY OF SAID HEAD SLOT, (G) A LINK PIVOTALLY CONNECTED BETWEEN SAID PIN AND SAID ROD WHEREBY SAID HEAD, PIN AND LINK OPERATIVELY CONNECT SAID SHAFT AND SAID ROD FOR SLIDING SAID ROD IN RESPONSE TO THE ROTATION OF SAID SHAFT, (H) A HOLD-DOWN BAR HAVING A HEIGHT LESS THAN THE HEIGHT OF SAID SLOT, SAID HOLD-DOWN BAR BEING OPERABLY SECURED TO SAID ROD FOR RECIPROCATION IN SAID, SLOT, (I) RESILIENT MEANS BETWEEN SAID HOLD-DOWN BAR AND SAID SHAFT, WHEREBY SAID HOLD-DOWN BAR RESILIENTLY ENGAGES A SHEET IN SAID SLOT BEFORE SAID PUNCHING MEMBERS ENTER SAID RECEIVING BORE UPON ACTUATION OF SAID SHAFT ROTATING MEANS, (J) AND ADJUSTABLE LUG MEANS EQUALLY AND SIMULTANEOUSLY MOVABLE TOWARD AND AWAY FROM SAID CENTER POSITION AND ENGAGEABLE WITH A SHEET TO BE PUNCHED TO CENTER SAID ONE PUNCHING MEMBER RELATIVE TO OPPOSED EDGES OF SAID SHEET.

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