US2404181A - Mechanical drawing press - Google Patents

Description

u y 4 w. KLOCKE.

MECHANICAL DRAWING gRE'SS Filed March 16, 1945 anuinm gig in III 42 F ATTORNEY I Patented July 16, 1946 UNITED STATES PATENT OFFICE MECHANICAL DRAWING PRESS William Klocke, Woodhaven, N. Y.

Application March 16, 1945, Serial No. 583,096

8 Claims.

This invention re ates to mechanical drawin presses and provides improvements therein.

Standard actions for mechanical drawing presses through the last half century have been the Leavitt action (U. S. Patent 451,224), the Klocke adaptation of the Leavitt action (U. S. Patent 955,173) used at the beginning and continued throughout the great development of the automobile industry, and, in later years, the Klocke-Dobson action (U. S. Patent 1,411,036). The Klocke-Dobson type of action has met with increasing favor in recent years, because of the economy of its construction and because, it-was found that in drawing certain metal and alloy sheets diflicult to draw, notably stainless steel sheets, better results were obtained with a blankthe parts of the blank-holder slide operating mechanism (including links for holding down the blank-holder slide under tension) are located above the bed of the press and within the lateral dimension of the side frames, the arrangement A struction which minimizes the number of working parts, in which the working parts are readily accessible so that damaged parts are readily removed and replaced, and which is economical to build.

The invention further provides a superior blank-holder action of the type wherein the blank-holder slide is actuated from a crank or eccentric through toggles, there being less recession of the blank-holder slide at the mid-part of the dwell than with any of the previously known standard constructions referred to above. The invention further provides a blank-holder action by which overlapping movement of the punch and blank-holder slides at the top of the strokeis avoided, or greatly minimized, maintaining at the same time the desirable dwell of the blank-holder throughout somewhat more than 90 of the punch slide movement, beginning at about half-way of the down-stroke of the punch slide and continuing until slightly after the punch slide reverses movement at the end of the working stroke.

One embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a View in side elevation of said embodiment; Fig. 2 is a view in front elevation; Fig. 3 is a detail view of the blank-holder slide, partly in side elevation and partly in vertical section; Fig. 4 is a diagram of the timing of the punch and blank-holder slides.

Referring to said drawing, numeral I0 designates the frame of the press comprising the bed crown l2, and side frames l4, l5.

Numeral l8 designates the punch-slide which is connected to a crank 2| on a crank-shaft (or equivalent) through an adjustable connecting rod 22. Crank-shaft 20 may be driven in a suitable manner, as through a gear wheel 24, pinnon 25, shaft 26 and fly wheel pulley 28, all mounted at the top part of the frame If].

Numeral 30 designates the blank-holder slide, mounted to reciprocate in gibs 32, 33 on the side frames l4, l5. The blank-holder slide is provided with a central opening 35 in which the punchslide 18 works, and through which a punch carried thereon (not shown) projects. guides 31 may be provided on the blank-holder slide 30 for the punch slide l8. The blank-holder slide 30 is usually, and preferably, attached to a cradle by means of adjustable connections 4|, 42, 43 and another similar one behind the adjustable connections 43, not shown. The adjustable connections are used in a well known way to adjust the position of a blank holder and the blank-holder slide with relation to a die on the bed I l in such manner that a sheet of metal between the blank holder and die will be properly gripped at the bottom of thestroke position of the .side frames |4, 5 and carry studs or pins 5| 52.

Attached to the pins 5|, 52 are links 55, 56 which work under tension in the blank holding position of the blank-holder slide 30.

Numerals 60, 6| designate bell cranks, one on the outside of each of the side frames l4, l5. These bell cranks 60, 6| turn on pins 63, 64 seated in the side frames. Advantageously; the bell cranks 50, 5| are located well above the'level of bed I I. The links 55, 56 are attached at their lower ends to pins 66, 61 on the bell cranks 60, 6| respectively. The links 55, 56 and the arms of the bell cranks to which they are attached constitute the levers of toggles.

Interior Above the bell cranks 13 at either side. The rock arms 72, 13 are connected to the bell cranks 60, 6| through relatively long links H, 18. The links H, 18 are attached to pins 89, 8| on the rock arms 12, I3 respectively and to pins 84, 85 on the bell cranks 69, El respectively. The rock arms 12, 13 and the links I1, 18 constitute the levers of toggles.

The rock shaft 111 is oscillated by means of a crank arm 8'! and pitrnan rod 89. The crank arm 81 is advantageously fastened on the crank shaft 29, the pitman rod 89 being attached to the pin 9| on the crank arm and to the pin 88 on the rock arm I2. The two cranks 2| and H! may be 7 60, BI is a rock shaft 1e. running across the press and having rock arms 12,

B. The crank pin 9| of the blank-holder actuating mechanism may be set on shaft'Zfl at the same angle as the crank in 2| which drives the punch slide. The blank-holder slide reaches blank-holding position slightly ahead of the punch contacting the sheet. Theblank-holder slide dwells in blank holding position throughout about one-half of the downward movement of the punch slide. The dwell of the blank-holder slide is continued for a few degrees after the punch slide starts its upward movement, so that the punch can start to pull out from the drawn shell before the shell is released by the blank holder.

set at the same angle on shaft 29 which is advantageous to economical manufacture. The arrangement of the parts is such that when the pins 5|, 66 on which the link 55' turns and the pin 63 on which the bell crank .60 turns are in dead center position (blank holding position), the centers on which the rock shaft 1|) and link ll turn (pins 8! 84 and center of rock shaft 19) move through a short are over dead center position, and also the centers on which the crank 87- and pitman rod 85 turn (center of shaft 29, pinv 9|, and pin 89) also move in a short are over dead center position.

The rock shaft 1i) is advantageously mounted in bearings 93 on the front of the side frames l4,

by readily assembled, and damaged parts are-l readily removed and replaced by new parts. This is of very great practical importance in shops having limited head-room, and in all kinds of shops in limiting the time a damaged press is out of use. a

a The blank holder operating parts comprise ten. sionelements or links 55, 56, which, in the blank holding position of the blank holder slide, press the blank holder slide down under tension, which,

. as previously stated, has been found to give su perior results in the dhawing of certain metals,

stainless steel sheets, for example. In all sizes of presses the location of the bell cranks 5| El and rock shaft HI, well above the bed of the press rovides a clear working space for feeding the press, and-enables drawn shells to be ejected or removed downwardly through the bed. The blank holder operating parts being located at the sides of the frame, and at a height above the bed, are out of the way so'as notlto be apt .to strike or injure the; workman. In medium and large size presses these parts would .be well above the head level of a gram Fig. .4, the movement of the punch slide be ing shown by the curve P and the movement of Thereafter the blank holder slide and punch slide move upwardly together, favoring the length of the interval that both the punch slide and blankholder slide are lifted from the die on the bed.

By setting the crank-pin 9| on shaft 29 at, (or

ap roximately at, within a lead of about 15) the same angle as crank-pin 2|, overlapping movements of the blank-holder slide and punch slide at the top of the stroke position is avoided or greatly minimized with reference to blank-holder actions in which the crank-pin which drives the blank-holder slide is set angularly considerably in advance of the crank-pin which drives the punch slide. There is obtained by the present invention (with its other advantages) the same thing with crank-pins set at the same, or nearly the same, angle as is accomplished in other constructions by setting the crank-pin for driving the blank-holder slide angularly in advance of the crank-pin for driving the punch slide, to wit, a blank-holder dwell beginning 'at about one-half way'of the down stroke of the punch slide and continuing to the end of the down stroke of the punch slide, and slightly or somewhat longer to enable the punch to start pulling away from the drawn shell before the shell is released by the blank-holder.

In the drawing, the blank-holder slide and its actuating parts are shown in blank-holding position. The pin 9| of crank 81 moves through an are passing through dead center with relation to the 'pin 80, and in this position the pitman rod 89 moves the crank arms 12, 13 and links 11, 18 through arcs passing through dead center with relation to the pins 84, and 85 and the axis of shaft 19. The links TI, l8 being relatively long, the amount of movement imparted to the bell cranks 69, .6! will be small as compared with the movement which would be imparted by 'a shorter link, for the reason that the arc through which the pin .89 is movedover dead center, for a shorter link, is deeper than the arc for a longer link, and consequently the amount of movement imparted to the bell cranks 66, 5| is greater for the shorter link.

While the pin 9| is moving in a short are in its dead. center position, and while the pin 8-!) is moving in a short arc across its dead center, the links 55 and 55 connected to the bell cranks 60 and 6| and to the cradle of the blank holder slide are on dead center with reference to the pins 63., 64. The amount of movement imparted to the bell cranks 56, 6| being very small, as just described, the .amount of recessive movement of the blank-holder slide will be verysmall. In presses according to the present invention the recession is on the order of a few thousandths of an inch (.014"), whereas in standard presses of the types referred to,[the amount of recession is about 3 times as much. Actually, however, there may not be any recessive movement of the blank-holder slide because of elasticity in the the blank-holder slide being shown by the curve links 55, 55. These links 55, 56 hold the blankas previously stated and as will be seen from.

the diagram Fig. 4, is such that both slides move upward in harmony and that the reversal of movement thereof at the top of the stroke occurs virtually simultaneously.

With the parts of the blank holder operating mechanism located well above the bed level, as illustrated in the drawing, drawn shells may be readily pushed or ejected through the bed of the press. This is an advantage of much practical importance over previous presses having rockshafts below bed level.

Drivingforce is imparted to the several levers and arms at good workin angles, thereby avoiding binding, an achievement often difiicult to obtain in press-construction, and this with the harmonious movement of the punch and blankholder slides referred to above, provides a very easy and smooth running press.

What is claimed is:

1. In a mechanical press, a frame, a blankh'older slide and actuating means therefor, said actuating means comprising a bell-crank, a link connecting one arm of said bell-crank and said slide, a toggle comprising a link connected to the other arm of said bell-crank anda rock arm pivotally connected to the frame of the press at a level above said bell-crank and above the working space between the bed of the press and the blank-holder slide, and a crank and pitman rod for moving the levers of said toggle to and from alinement.

2. A mechanical press according to claim 1, further comprising a crank-shaft for driving a punch slide, and wherein said crank for actuating said blank-holder slide is set at substantially the same angle as the crank on said crank-shaft.

3. In a mechanical drawing press comprising a frame, a bed, a blank-holder slide and actuating means therefor, said actuating means comprising a bell-crank pivoted on the press frame, a link connected to said blank-holder slide and to said bell-crank at a point below and substantially in line with the link connection to the blank-holder slide and acting on said blank-holder slide under tension in the blank-holding position of said slide; a toggle connected at one end to said bell crank and at its other end to the press frame a a point above its connection to said bell crank, and a crank and pitman rod for actuating said toggle, said parts being so interrelated and arranged that the center on which said bell crank turns and the center on which the link connecting the blankholder slide and bell crank turns, are in substantial alinement, and the centers on which the toggle turns, and the centers on which said crank and pitman rod turn are also in substantial alinement, in the blank-holding position of said slide.

' 4. In a mechanical drawing press according to claim 3, wherein said bell crank is pivoted at a point substantially above the level of the bed of the press.

5, In a mechanical drawing press comprising a frame, a bed, a blank-holder slide and actuating means therefor, said actuating means comprising a bell-crank pivoted 0n the press frame at a point substantially above the level of the bed of the press, a link connected to said blank-holder slide and to said bell-crank at a point below and substantially in line with the link connection to the blank-holder slide and acting on said blankholder slide under tension in the blank holding position of said slide, a rock-shaft, mounted at the upper part of the press-frame, having a rockarm, a link connecting said rock-arm and an arm of said bell-crank, said link and rock arm together constituting a toggle, and a crank and pitman rod for actuating said toggle, said parts being so interrelated and arranged that the center on which said bell-crank turns and the centers on which the link connecting the blankholder slide and bell-crank turns are in substantial alinement, and the centers on which the toggle turns, and the centers on which said crank and pitman rod turn, are also in substantial alinement, in the blank-holding position of said slide.

6. A mechanical drawing press, according to claim 5, further comprising a main crank-shaft at the top of the press frame, and wherein said crank which is connected to said pitman rod is a part of said main crank-shaft.

7. A mechanical press according to claim 3, further comprising a crank-shaft and a punch slide driven thereby, and wherein said crank arm forming part of the blank-holder actuating mechanism is set at substantially the same angle as the crank on said crank-shaft which drives the punch slide, and wherein said blank-holder reaches blank-holding position about mid-way of the down-stroke of said punch slide, dwells until slightly after said punch slide begins its upward stroke, and thereafter moves upwardly simultaneously with said punch slide.

8. In a mechanical drawing press, a frame, a blank-holder slide and actuating means therefor, said actuating means comprising a bell-crank, a link connecting one arm of said bell-crank and said slide, a toggle comprising a link connected to the other arm of said bell-crank and a rock arm, a crank-shaft and pitman rod for moving the levers of said toggle to and from alinement, a rock shaft having said rock arm thereon, running from one side to the other of the frame at a level above said bell-crank and above the working space between the bed of the press and the blank-holder slide, acting to transmit blank-holder actuating force from one side of the press to the other, and duplicates of said bell-crank, link, and toggle-constituting parts at the side of the press opposite said pitman rod.

WILLIAM KLOCKE.

Disclaimer 2,404,181.William Klocke, Woodhaven, N. Y. MECHANICAL DRAWING PRESS. Patent dated July 16, 1946. Disclaimer filed Feb. 17, 1948, by the inventor.

Hereby enters this disclaimer from claim 1, of any arrangement of the link connected to the slide which does not extend upwardly from the bell-crank.

[Ofiic'ial Gazette March 23, 1948.]

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