US2851888A

US2851888A - Portable punch press

Info

Publication number: US2851888A
Authority: US
Inventors: Scholin Axel
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-09-22
Filing date: 1953-09-22
Publication date: 1958-09-16
Anticipated expiration: 1975-09-16

Description

Sept. 16, 1958 A. scHoLlN 2,351,838

PORTABLE PUNCH PRESS Filed Sept. 22, 1955 5 Sheets-Sheet 1 5 x m i2 66 are! ,fic/oZziz Sept. 16. 1 58 A. SCHOLIN 2,851,888

PORTABLE PUNCH PRESS Filed Sept. 22. 1953 5 Sheets-Sheet 2 Sept. 16, 1958 A, g iZExIQLEN $553,838

PORTABLE PUNCH: mass Filed Sept. 22, 1953 5 Sheet M-Sheet 4 PORTABLE PUNCH PRESS 5 Sheets-Sheet 5 Filed Sept. 22, 1953 United States Patent PORTABLE PUNCH PRESS Axel Scholin, Chicago, in.

Application September 22, 1953, Serial No. 381,617

4 Claims. (CI. 74-38) The present invention relates to a portable punch press particularly designed for punching metal sheets.

The punch press comprises a frame having a fixed head and a movable plunger interconnected to the head by means of a pair of toggle links. A crank operated by an electric motor mounted on the frame operates a pair of horizontal arms connected at one end to one of the toggle links. Each of the horizontal-arms has a slot engaging the pin of a crank and is free to idle until a trig ger-operated lever system is manually operated to move a latch member into engagement with the horizontal arms to arrest movement of the crank pin in the slot, at which time the arms are effective to rock the toggle links and raise and lower the plunger.

It is an object of this invention to provide a punch press with a handle to facilitate carrying it from place to another and another handle cooperating with the carrying handle to facilitate positioning it properly with respect to the work material.

Another object is to provide a trigger adjacent the carrying handle'to facilitate control of the punching operation when the motor is running.

Other objects of the invention and the various advantages and characteristics of the present portable punch press will be apparent from a consideration of the following detailed description, taken in conjunction with the accompanying drawings showing a preferred illustrative embodiment of the invention, in which:

Fig. 1 is an elevational view, taken from the right hand side, showing a punch press embodying the invention;

Fig. 2 is a fragmentary elevational view of the left hand side of the punch press, looking in the directions of the arrows 2-2 in Fig. 3;

Fig. 3 is an end elevational view, taken from the rear of the punch press looking in the direction of the arrows 3-3 of Fig. 2;

Fig; 4 is a fragmentary vertical sectional view of the punch press showing the horizontal arms and the trig ger controlled mechanism for operating the latch member to prevent the horizontal arm from idling relative to the crank pin;

Fig. 5 is a detail perspective view of the latch member;

Fig. 6'isa front elevational view of the punch press, taken along the line 6-6 of Fig. 4;

Fig. 7 is a transverse sectional view, taken along the line 7-7 of Fig. 6;

Fig. 8 is a fragmentary side elevational view showing one of the bearings for the shafts of the various gears;

Fig. 9 is a cross sectional view, taken along the line 9-9 of Fig. 8; i

Fig. l() is a fragmentary elevational view of the operating mechanism withthe frame and motor omitted;

Fig. 1 l is a view similar to Fig. 10, showing the mechanism with the crank pin in two different positions, one position being shown in dotted lines; and

Fig. 12 is a detail perspective view of the yoke operated by thetrigger to move the latch member into latching en- 2,851,888 atented Sept. 16, 1958 Referring to the drawings, the punch press comprises 7 a frame 10 having a base portion 11 provided with a flat bottom 12 so that it may stand upright on any suitable flat supporting surface and a bed 13 on which die block 14 is secured by a plurality of bolts 15. A suitable die 16 may be held in the die block in any suitable manner, as by a set screw 17. The die 16 is provided with a vertical bore 13 which is aligned with a larger bore 19 extending through the base portion of the punch press. Although the die 16 is for punching holes through a sheet of metal it will be understood that different types of dies suitable for other operations, such as stamping, forming, or shearing, may be substituted for the die 16.

A fixed intermediate frame portion 20, spaced above the bed 13 cooperates therewith to form a throat 21 to permit entrance of the work pieces. A horizontal bore 22 provides a guide-way in which a stop member 23 is slidably mounted. The stop member is held in any adjusted position by a screw 24. The throat 21 is deeper than the insertion of the work requires, and the stop member 23 effectively limits the depth to which the work piecesflm'ay be inserted. Frame portion 20 is provided with a vertical bore 25 aligned with

bores

18 and 19. A plunger 26', slidably mounted in bore 25, is provided with a recess 27 extending upwardly from its lower edge. A punch pin 28, adapted to fit with die 16, is held in place in the recess 27 by means of a set screw 29. A stripper member 30 is pivotally mounted on the fixed portion 20 to swing back into throat 21 and is provided with a spring 31 urging it outwardly.

The upper end of plunger 26 is pivotally secured to the lower end of a toggle link 32. The upper end of. link 32 is pivotally connected to the central portion of a bifurcated toggle link 33 which straddles it. The upper end of toggle link 33 is pivotally secured to a bracket 34 fixed relative to the top of frame 10. The top of frame 10 is provided with a threaded vertical bore 35 anda tubular sleeve 36 is threaded therein. Bracket 34 is provided with a stud 37 which extends through sleeve. 36 and is secured in place by a nut 38 tightened against the top of the sleeve. The vertical position of sleeve 36 may be adjusted within a limited range to regulate the position of bracket 34 and thereby vary the stroke of plunger 26 which is determined by the vertical distance between the pivot at the upper end of toggle link 33 and the pivot at the lower end of toggle link 32.

A pair of parallel horizontal arms 39 are held in spaced relationship by an intermediate bar 4% and each arm is pivotally connected at one end to the lower end of toggle link 33. The portion of each arm 39 extending beyond the end of bar 40 is provided with a longitudinal'slot 41 and a crank pin 42 extends through both slots 41. The crank pin is mounted on a pair of crank arms 43 which are rotated by an electric motor 44 having a motor shaft44.

- The motor is provided with a base 45 and is mounted on the rear of frame it) by means of a plurality of screws or bolts 45'.

A plate 46, secured to the rear edge of frame 10 by a plurality of bolts 46 is provided with a pair of plates 47 extending rearwardly therefrom in parallel spaced relationship. Plates 47 may be integral with plate 46 or welded thereto. Plate 46 is provided with a large central opening 47' (Fig. 4) aligned with a corresponding opening in the frame 10 to permit arms 39 to pass therethrough. A plurality of spacing rods 48 extend trans versely between opposite edge portions of the plates-47.

A roller 48' is rotatably mounted on the rod 48 adjacent the upper edge of plates 47 for a purpose hereinafter described.

Each plate 47 is provided with a plurality of self-aligning bearing assemblies 49 aligned in opposite plates to support a plurality of shafts 50 carrying a series of gears 51, the shafts 50 and gears 51 comprising a reduction gear train for motor 44. The platesv 47 are not thick enough to provide suitable bearing support for the shafts 50, and their thickness is built up, as shown in Figs. 8 and 9, by annular disks 52 secured on opposite sides of each plate 47 adjacent each hearing by means of screws 53. Each disk is provided with an outwardly dished flange 54 having its inner surface rounded, and the periphery of the bearing alloy 55 is shaped to fit within the flanges 54. A pin or stud 56, projecting from the bearing alloy, is positioned within a recess 57 in the edge of plate 47 to prevent the bearing alloy from rotating in the plane of the plate 47. The pin 56 fits in recess 57 loosely enough to permit a slight movement transverse to the plane of the plate 47 and the rounded outer end of the bearing alloy 55 in contact with the rounded inner surface of flanges 54 'moves in the same direction to permit selfalignment of each bearing with its shaft.

A latch member 58 is mounted on crank pin 42 and moves therewith as the crank arms 43 are rotated by the motor. As shown in Fig. 5, the latch member comprises two

parts

59, 60, each provided with a semicircular recess 61 which fits around crank pin 42. The

parts

59, 60 are secured together by bolts or screws 62. The latch portion 59 has a pair of

legs

63 and 64 adapted to straddle the end of the bar 40 secured between the arms 39. The leg 64 of the latch member is provided with a shoulder 65 facing the end of bar 40. The underside of leg 63 engages the upper surface of bar 40 to limit the lowermost position of

legs

63 and 64 and to maintain the straddling relationship with the bar 40 while the motor 44 is running.

Operation of motor 44 rotates the crank pin in a fixed orbit and the latch member 58 is moved forwardly and rearwardly with the crank pin. The crank pin is freely rotatable in the recess 61 and the weight of the

legs

63 and 64 keep the leg 63 in engagement with the top of bar 40. The roller 48' coacts with leg 63 to prevent the latch 58 from swinging upwardly by centrifugal force as the crank pin 42 starts its forward movement. Roller 48' engages the upper surface of leg 63 and holds it down as the latch moves forwardly. The length of

legs

63 and 64 is sufficient to keep the bight portion between

legs

63 and 64 from striking against the rear end of bar 40 and to prevent disengagement of the leg 63 from the top of bar 40 throughout the orbit of the crank pin. The crank pin 42 extends through the slots 41 and does not move the horizontal arms 39 as long as the latch member isfree to reciprocate relative to the bar 40.

Frame is provided with a rearwardly extending handle 66 adjacent its upper edge. A trigger 67, pivoted to frame 10 below handle 66, as indicated at 68, has a finger piece 69 extending approximately parallel to the handle a short distance below it so that the handle and finger piece may be grasped in the operator's hand and a slight squeeze will lift the lever 70 on the opposite side of pivot 68. A lever 71 pivoted at its upper end to lever 70 is pivoted at its lower end to a horizontal rod 72 (Figs. 10 and 12).

A horizontally disposed yoke 73, positioned below latch member 58 has a forwardly extending tongue 74 pivotally mounted on rod 72 and its rear end is pivotally mounted on a rod 75 carried by the plates 47 (Fig. 4). The tongue 74 is directly below the lower arm 64 of latch member 58. When the trigger 67 is squeezed upwardly against handle 66 the lever 71 lifts the front end of yoke 73 upwardly and tongue 74 moves latch member 58 pivotally upwardly about crank pin 42 until the shoulder 65 is aligned with bar 40. As the orbit of crank pin 42 moves the latch member forwardly shoulder 65 engages the rear end of bar 40 and moves arms 39 forwardly.

The forward movement of arms 39 tends to straighten the toggle links 32 and 33. Since the bracket 34 holds.

the upper end of toggle link 33 in fixed vertical position the link 32 moves downwardly and carries plunger 26 with it to drive punch pin 28 downwardly into the bore 18 of die 16 to punch a hole in a work piece, such as a metal strip or sheet, positioned on the die. As long as the squeezing pressure against trigger 67 is maintained the punch pin will be driven downwardly with each forward movement of the arms 39, and a work piece on die 16 may be moved between strokes to form a series of holes in the work piece very rapidly. If the trigger is squeezed and the pressure is immediately released, the punch will operate once and then the arms 39 will resume their idling motion.

The punch press is provided with a pressure pad comprising a bracket 76 secured to the upper surface of the intermediate fixed portion 20 of the frame by means of screws 77 and having a horizontal flange 78 terminating adjacent the upper end of plunger 26. Toggle link 32 has one lower edge cut away, as indicated at 79, and a stud 80, slidably mounted in a longitudinal recess (not shown), has one end bearing against a block 81 loosely positioned on flange 78. A compression spring 82 encircling stud 80 between the block 81 and the edge of toggle link 32 adjacent the stud exerts constant force against the block 81 to retain it in place. Spring 82 exerts force which raises the toggle link 32 after termination of the downward motion and maintains the angle between

links

32 and 33 shown in Fig. l. A leaf spring 83 is secured to frame 10 by a screw 84 and engages the rear edge of toggle link 33 to prevent overthrow of arm 39 in the direction of the motor when the toggle has been moved rearwardly by the upward movement of plunger 26.

Handle 66 is sufficient for carrying the punch press, but because it is sometimes necessary to position the press with some degree of precision I prefer to provide an auxiliary handle 85 which is secured to the bottom of frame 10 by any suitable means, such as screws 86. The handle 85 in addition to facilitating the accurate positioning of the punch press, also facilitates carrying it around because it permits the use of two hands for this purpose.

Although I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details may be modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact details of construction described.

I claim:

1. A portable punch press comprising a frame, a carrying handle, a motor mounted on said frame, a pair of toggle links pivotally mounted on said frame, a horizontally movable arm connected at one end to one of said toggle links, a crank operatively connected to said motor, a crank pin mounted eccentrically of said crank, said movable arm having a longitudinally extending slot fitting around said pin, said slot being long enough to permit said arm to idle during the complete rotation of said crank, a latch member pivotally mounted on said crank pin and movable therewith, a bar rigidly secured to said horizontal arm, said latch member having a pair of legs straddling said bar in a vertical direction as said latch member is reciprocated by rotation of said crank, a trigger mounted on said frame, said trigger including a finger piece positioned adjacent said carrying handle and a lever operatively engaged with said latch member, said lever being moved upwardly upon actuation of said finger piece to move said latch member into engagement with said bar whereby said horizontal arm moves said toggle links to actuate a punch.

2. A portable punch press comprising a frame, a carrying handle on said frame, a motor mounted on said frame, a crank rotated by said motor, a crank pin mounted eccentrically of said crank, a pair of toggle links operable to actuate punching mechanism, said toggle links being normally held in inactive position, an arm pivotally secured at one end to one of said toggle links, operatively connected with said crank pin, a bar secured to said arm, a latching member mounted on said crank pin, and a trigger mounted on said frame, said trigger having a finger piece positioned adjacent said carrying handle and operable to move said latch member into engagement with said bar and thereby cause said arm to move said toggle links out of said inactive position.

3. A portable punch press comprising a frame having a fixed head, a movable plunger interconnected to said fixed head by means of a pair of toggle links connected to said head and plunger respectively, a horizontal arm connected to one of said toggle links, means for reciprocating said arm to actuate said toggle links to move said plunger downwardly, said means including a crank arm, a latch member directly connected to said crank arm and reciprocable therewith, said arm being provided with a longitudinally extending slot into which said crank arm extends and in which it is slidable to permit said horizontal arm to idle while said latch member is being reciprocated, a finger operated trigger operable to move said latch member into engagement with said horizontal arm and thereby translate movement of the latch member into reciprocation of said arm to actuate said toggle links to move said plunger and means for rotating said crank arm.

4. A portable punch press comprising a frame member including a fixed head, a vertical plunger interconnected with said head by means of toggle links, a horizontal arm connected to one of said links, said arm having a longitudinal slot, a crank provided with a crank pin engaging said slot, means for rotating said crank, said arm idling while said crank is being rotated, a latch member mounted on said crank pin, and a trigger operated lever system manually operable to bring said latch member into engagement with said arm to arrest movement of said crank pin in said slot, whereby subsequent movement of said crank pin is effective to actuate said toggle links to reciprocate said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 1,434,060 Lautenschlager Oct. 31, 1922 1,650,411 Yates Nov. 22, 1927 1,838,582 Skillman Dec. 29, 1931 1,926,576 Beatty Sept. 12, 1933 2,189,742 Ruppert Feb. 6, 1940 2,562,044 Klocke July 24, 1951 2,576,328 Allison Nov. 27, 1951 2,652,291 Magarian Sept. 15, 1953 FOREIGN PATENTS 14,279 Great Britain June 25, 1904