US2539902A

US2539902A - Hold-down guard mechanism for trimming presses

Info

Publication number: US2539902A
Authority: US
Inventors: John D Foley
Original assignee: H O CANFIELD CO
Current assignee: H O CANFIELD CO
Priority date: 1948-01-24
Filing date: 1948-01-24
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

Jan. 30, 1951 J. D. FOLEY HOLD-DOWN GUARD MECHANISM FOR TRIMMING PRESSES Filed Jan. 24, 1948 INVENTOR. LIUHN D. FOLEY ATTORNEY.

Patented Jan. 30, 1951 UNITED STATES PATENT OFFICE HOLD-DOWN GUARD- MECHANISM FOR TRIMMING PRESSES John D..Foley, Westport, Conn assignor to The H. O. Canfield '00:, Bridgeport, Conn., a-corporation of Connecticutv Application J anuary.-24, 1948, Serial No; 4,2011.

- 1 claim. I

The present invention relates to a holddownguard mechanism for trimming presses, andhas for-an object to provide a.-mechanism of. this character of relatively simple and inexpensive construction, and which will'be automatic in operation as to power actuation so that it does not depend upon the volition or judgement of the.

operator of the press to perform-its actuating function.

The guard mechanism ofthe inventionis especially adapted for cooperative incorporation in a trimming press of the type which trims molded. articles from a sheet or'strip of molded rubber. or the like, and wherein the flexibleenature. of'

such material is such that. the operator. must holdthe. material. relatively closeto .the. die and punch ofthe. press,v so as to. properly position the articleto betrimmedwithinthe. die. With. this requirement in .viewit is a further object of."

the invention to. provide. a. guard' mechanism which will effectually prevent positioning of the fingers of the operator inthepathoffthepunch while at the. same time permittingthe material to be held in close proximity, to the punchand" die. It is further. proposed to providexa guard mechanism having aguard elementadaptedto act as a holding means for the materialto be trimmed; ,so as to firml retain it upon the die preparatory to engagement oil the. die by the:

punch.

A further object is to provide a guard mecha-. nism having means for automatically causing the actuation of the. power. means for driving the punch; and particularly to provide a precision electric switch of the micro type; which adapted'to operate withinvery closelimits, so" that the punch. cannot be operated until the guard is in an exact predetermined position in relation to thedie.andthework... Another object is to provide a guard'mechanism particularly adaptedfor cooperation;withqaw solenoid operated trimming press, the: micro switch,,

forming part of the mechanism, being so connected as to directly openand closethe electric circuit of; the solenoid, and. resulting in a fast-z.

operating press without an unduelag betweenthe operation of'the guard mechanismand the;punch actuating solenoid.

With the above and other objects in view, an embodiment of the invention is. shown in the ac-. companying drawings, and this embodimentiwill be. hereinafter more fully described with refer: ence. thereto, and the invention. will be fi'nally point'ediout in the claim.

"Inthedraw-ings:

Fig. 1 is a side elevationof'a trimming press embodying the invention, the dot-and-dash linesv indicating the position of the guard mechanism inits-operative position, as well as the position of the article to be trimmed.

Fig. 2 is a front elevation.

Fig. 3 is a -horizontal sectional plan view taken along the line 3-3 of Fig. 1.

Similar reference characters indicate corresponding parts throughout the severalfigures of the drawings.

Referring to the drawings, the trimming press, according to the illustrated exemplary embodiment. of the. invention, comprisesv a horizontal table or bed Iii, upon: which there is rigidly secured avertical cylindrical post H, having ad.-

justably: mounted thereonfor vertical adjust-- ment abearing head l2, secured in-its position... ofadjustmentby means of a clam-ping bolt l3.- providedrin .therearward split portion I4 of the.

head.

In theforwardly projecting end of the head there is provided a vertically disposed bearing bushing. I5 for supporting the punch driving shaft, as will presently more fully appear. In-

termediate post Hand the bearing bushing "5,, the. bearing. head is provided with a transverse vertical shoulder l6 and a transverse recess IT,

avertically disposed platel8 being engagedat.

its lower end in the recess Hand rigidly secured by screws I9 to the shoulder 16. Upon the forward side of the plate l 8.there is secured a bearing block 20 having a bearing bushing 2i therein. in axial alignment with the bearing bushing. l5...

and which in cooperation therewith provides a relatively long bearing support for the punch. drivingshaft.

Inspaced relationabove the bearing block 20.

there. is secured uponthe. forward face. of'the;.

plate 18 asol'enoid unit 22 having avertically movable plunger. armature 23, the winding. of." the coil of the solenoid being such as to drive the armature downwardly when it is energized.

A punch driving shaft' 2A is engaged for vertical movement in the bearing bushings. l5 and .2 l

andis provided near itsupper endwith a collar. 25," between which and, the bearing blockv 20' thereisprovid'ed a helical'compression spring 26;.

normally-forcing the shaft upwardly. At its upper endathe shaft is provided with a transverse.

semi-cylindrical groove 21, engaged by a cross.-

shaft '28 providedat'thelower end of the. plunger.

23, so that upon down movement of the plunger.

the..shaft.is.pressed downwardly, the spring returning.;.-the .shaft..and'jplunger. to their raisedpgisiti. when theisolenoid is..de.-energized;

. Wit 1 -a=verticalsocket29 in the lower-endof the shaft 24' there is engaged the punch 33 secured in place by a set screw 3!, and which is adapted to cooperate with a die 32 secured upon the table l9. The surface of this die surround.- ing its cutting edge is of truncated cone shape for the purpose of providing clearance space for the operators fingers, as will hereinafter more fully appear.

Anelectric switch 33 of the micro type is secured at the upper end of the plate I8 upon its rearward side, and is provided with an actuating pin 34 for engagement by the guard mechanism, as will presently more full appear. This switch is connected in the circuit of the solenoid, so

that the solenoid is energized and de-energized in the respective closed and open positions of the switch.

The safety mechanism comprises a U-shaped band member 35 engaged about the forward end of the bearing head [2 and secured at its side by means of screws 33, the leg portions or" the band projecting rearwardly from the bearing head and being provided in rearwardly spaced relation thereto with a-transverse shaft 37, upon the pro jecting ends of which there is pivotally mounted a U-shaped lever 38. The lever extends forwardly at each side of the bearing head and is provided in the forward end of each of its side legs with a slot 39, for cooperation with the vertically movable guard assembly, as will presently more fully appear.

At each side of the bearing head, in transverse alignment with the axis of the punch actuating shaft, there is secured upon the band member 35 by means of screws 40 a bearing block 4|, having a vertical bearing passage 12 therein. In the bearing blocks 4! there are engaged for vertical sliding movement slide rods 33, threaded at their lower ends and screwed into the upper flattened end portions 44' of the side arms 45 provided at each side of the tubular guard member 36. The guard member is axially aligned with the punch 30, and is normally disposed in its raised position between the lower end of the punch and the die 32, being sufiiciently spaced above the die to permit placing of the material to be trimmed upon the die. At the upper end of each of the rods 43 there is provided a forked head portion 41, engaged by the forward end of one of the side legs of the lever 38, and provided with a cross pin 48 engaged in the slot 39 of the lever.

The lever 38 is normally maintained in its raised position by means of helical expansion springs 49 connected between studs e upon each of the side legs of the lever and studs 5i provided at each side of the plate I8. Downward movement is imparted to the lever by means of pull rods 52, connected to each of the side legs of the lever by means of studs 53, these pull rods extending downwardly through passages 54 in the bed It to a cross-head 55, to the central part of which there is secured a pull rod 55, connected at its lower end to an operating pedal 5'! connected by a hinge 58 to the floor. The pedal is normally held raised through the action of the springs 4'9. Upon pressing the pedal downwardly the lever 38 is swung downwardly to bring the guard member downwardly into guarding relation with the die 32 and the work engaged thereon, as shown by the dot-and-dash lines in Fig. l.

A yoke member 59 is secured at its lower end to the side legs of the lever 38, and upon its upper mounted contact screw 60 held in its adjusted position by retaining nuts 6 l and 62, this contact screw adapted as the lever 38 is swung downwardly to engage and depress the pin 34 of the micro switch 33, as shown by the dot-and-dash lines, Fig. 1. The micro switch is so positioned with respect to the contact screw that the circuit 53 of the solenoid is closed at the exact predetermined point when the guard member engages the work piece to press it against the die, whereupon the downward operation of the plunger presses the punch downwardly into engagement with the die. It will thus be seen that if a finger of the operator is disposed in the path of the punch, the guard member cannot be brought downwardly to the point where the micro switch will be actuated. The tapering of the surface of the die permits the fingers to be placed in very close proximity to the cutting edge of the die without danger of being hit by the punch.

I have illustrated and described a preferred and satisfactory embodiment of the invention, but it will be understood that changes may be made therein, within the spirit and scope thereof, as defined in the appended claim.

What is claimed is:

In a press holddoWn-guard mechanism, a fixed tool part, a vertically movable tool part, power means for vertically moving said movable tool part downwardly and upwardly respectively into and out of relation to said fixed tool part, a holddown-guard element comprising a tubular wall surrounding said movable tool part and vertically I movable downwardly and upwardly in parallel' relation to the movement of said movable tool part respectively into and out of guarding relation to said fixed tool part, said fixed tool part having an opening for engagement by said movable tool part and having an annular downwardly tapered wall surrounding said opening and disposed directly beneath the tubular wall of said holddown-guard element, means normally urging said holddown-guard element into raised position, manually operable actuating means connected to said holddown-guard element to move it downwardly into holding relation with the upper side of the work engaged upon said fixed tool part independently of the movement of said movable tool part and said power means, means for controlling the operation of said power means, and means carried by said manually op: erable means for operating said last named means at a predetermined point of movement of said holddown-guard element.

, JOHN D. FOLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name r Date 618,065 Dicks Jan. 24, 1899 779,427 Jessop Jan. 10, 1905 915.438 Hornor Mar. 16, 1909 1,179,477 Thomas Apr. 18, 1916 1,551,447 Wilde Aug. 25, 1925 1,684,296 Brodsky Sept. 11, 1928 2,236,730 MacBlane Apr. 1, 1941 2,315,151 Booth Mar. '30, 1943" 2,348,566 Papazian May 9; 1944""-