US1718435A - Hydraulic cushion for metal presses - Google Patents

Description

June 25, 1929. F. J. RODE a' HYDRAULIC CUSHION FOR METAL PRESSES Filed April '7, 1928 3 Sheets-Sheet June 25, 1925. I F, J, RODE 1,718,435

HYDRAULIC CUSHION FOR METAL PRESSES Filed April 7, 1928 3 Sheets-Sheet June 25, 1929. F, J, RODE 1,718,435

HYDRAULIC CUSHION FOR METAL PRESSES Filed April '7, 1928 3 Sheets-Sheet 3 Patented June 25, 1929.

UNITED STATESy PATENT foFFlcE.

FRIEDRICH J'. RODE, OF CHICAGO, ILLINOIS, ASSIGNOR TO MARQETTE TOOL & MIG.

' CO., OF CHICAGO, ILLINOIS, A CORPORATION` 0F ILLINOIS.

HYDRAULIC CUSHION FOR METAL PRESSES.

i Application med april 7,

In hydraulic cushioning devicesy for presses of the character in which the metal is shaped by means of co-operating dies, one of which dies is reciprocable toward and away from the other, the wor'k being clamped or held by means of a blank or Work holding element that co-operates with the reciprocable die member, and the blank or work holder ele-v ment being resisted in its movement in one direction by the said cushion, it has been found that when the piston in the cushioning device starts to move 'against the stress or resistance of the liquid, and especially when said liquid is non-compressible, there is a severe shock imparted to the machinery before the liquid starts to move under the stress or action of the piston. This shock is undesirable and detrimental as it strains the parts of the press, oftentimes resulting in considerable injury.

It is oneof'the objects ofthe present invention to overcome these difficulties and objections and to provide in a cushion of this charactery improved means for automatically eliminating or relieving the parts of the press and machine `from such shocks or strams. f v

To the attainment of these ends and the accomplishment of othernew and useful objects as Will ap ear, the invention consists in the features o novelty inl substantially the construction, combination and arrangement of the several 'parts'hereinaftermore fully described` and claimed rand shown in the accompanying drawings illustrating this invention, andV in "which Y Figure 1 is a view partly in side elevation, partly in fsection, with arts broken away and .with parts omitted o asheet metal press having a cushioning means constructed in accordance with the uprinciples of this in-v vention applied thereto, tion which the parts will lassume when the ram or movable die-member issubstantially` at the limit of its upward movement.

Figure 2 is a view in side elevation of Figure l with parts omitted, parts broken away and `parts in section.`

Figure 3 is an enlarged view paru-y in @1evation,

partly in section `and partly broken away and with parts omitted, showin the position of the parte when the ram or p ungshowing the posiymeral 30.v

1928. Serial N'o. 268,325.

er is at the limit of its lowermost movement.

Referring more particularly to the drawings the numeral 10 designates generally the support of the press upon which the bed plate 11 rests, uprights 12 being provided and along whichl uprights the ram or plunger 13 carrying the movable die member 14 is reciprocable by means of a crank shaft 15 journaled in the uprights, and which shaft is rot-ated in a manner usual in presses of this character.

Mounted upon thebed plate 11 is a die 16 with which the reciprocatmg die co-operates. Encompassing the die 16 is a blank or work holding member 17, the latter being supported by means of pins 18 which pass loosely through the bed plate 11 and have contact with and are supported by means of apressure late or pad 19, all as usual in presses of t is character.

As shown in Figure 2 of the drawing, the pressure pad 19 constitutes an extension of a pad or plate 20, through the medium of supporting pins 21.

Arranged beneath the press and mounted upon a suitable support 22, which latter may be held in position by means of hanger memvation and is provided with a predetermined A supply of liquid through a suitable fill openine28. ading from the tank is a pipe 29 which has communication with the bottom of the cylinder 24 beneath the piston 25.

Arranged in the pipe 29 and at an suitable point is a valve containing e ement designated generally by .the reference nu- This element has a passage 3L therethrough, which when open will permit the liquid to flowv from the tank 27 through the upper portion of the pipe 29 and into the lower portion of the pipe 29 to' be delivered to the cylinder. 1

This passage 31 is provided with a valve seat 32 with which a valve 33 vco-operates for opening and closing the passage to permit or interrupt the flow of liquid therethrough. I

-The valve 33 is adapted to be controlled in any suitable manner so as to yieldingly hold the same upon the seat 32 and to that end there may be provided a cylinder 34 within which is a piston 35 that is connected tothe valve stem 36, the cylinder being held .in position in any suitable manner so that the valve stem 36 will pass through' a suitable guide 37.

Communicating with the top of the .cyl-

i inder 34 and on the upper `side of the piston is a pipe 38 which delivers iluid, such as air to the cylinder from any suitable source through a pipe 39, and from which pipe a. branch pipe 40 leads .that connects with the pipe 38. A pressure regulating valve 41 mayl be provided in the branch 40 and a gauge 42 may also' be provided in the pipe. When the fluid flows into the cylinder 34 the valve 33 Will'be moved against the seat 32 and the degree of pressure with which lthe valve 33 is held seated'by the fluid pressure may be controlled in any suitable manner nd varied by means of the regulating valve Fluid which is supplied through the pipe 39 is also delivered to the tank or receiver 27 by means of a branch pipe 43A leading to the tank and in which branch pipe is a pressure controlled valve 44 by means of whichb the pressure may be varied, a gauge y45 and a valve 46, by means of which latter the supply of i'luid to the tank or receiver 27 may be cut oi.

The valve 33 and valve seat 32 are so arranged that the pressure within the tank or receiver 27 will tend to seat the valve so that it will not be unseated by such pressure but is adapted to be unseated by the pressure exerted u on the liquid in the cyl1nder 24 beneath t e piston 25. That is when thedie 14 operates upon the work 47 toshape the same and depress the pad 19, the valve 33 will be maintained seated until the pressure upon the liquid in the cylinder 24 ex-.-

ceeds the pressure in the cylinder 34 which holds the valve 33 seated. When the pressure in the cylinder 34 is overcome the valve- 33 will be unseated and the liquid from the cylinder 24 will How back through the pipe 29 to the receiver 27. f

l The' deliveryl of the liquid from; the rer'eiver 27 into the cylinder 24 is controlled by means of another valve 48 which co-operates with a valve seat 49 arranged in a by-pass 50 in the passage 31, and the valve 48 is adapted to be actuated ffrom some movable part of the press preferably by L its other end to alever 54 ulcrumed as at 55, the lever being connected .to the stem 56 of the valve 4,8, a yieldable section 57 being preferably provided in the rod 52 to prevent injury to the parts. f

Thus during a predetermined time in the cycle of operation of the press or at the time whenv the ram 13 is approaching the limit of its upward movement, the crank 51 will begin to unseat the valve 48 so that by the time the crank is at the highest point the valve 48 Will be completely unseated to permit the liquid in the tank orreceiver 27 to be `delivered under the influence of the air or Huid pressure upon the liquid, through the pipe 29, passage 31, by-pass 50, and the Lower section f the pipe 29 to the bottom of the cylinder 24 beneath the piston 25.

While the liquid is thus flowing into the cylinder 24 the valve 33 will be seated. When the valve 48 is seated the liquid will be trapped in the lower section of the pipe 29 and the bottom of the cylinder 24 and will bedelivered back to the receiver 27, through the passage 31 when the valve 33 is unSeatedy fupon the liquid in the cylinder 24 by the piston 25. y

Wheh the Yliquid is thus trapped 1n the cylinder 24 and when the piston 25 is lowpressure pad 19, at

ered by depressing the acts agamst theinstant when the piston 25 the pressure.- of the liquid in the cylinder 24, the piston is suddenly interrupted rin its movement which causes a considerable stress or strain to be exerted upon'the crank IShaft 15 and other parts of the mechanism,

if some means is not provided to relieve such a shock.

Therefore to overcome this detrimental and sudden shock, means are provided Jfor enlarging aI portion of the spacein which the trapped liquid is contained. In the present exemplification of this invention a portion of the passage 31 in the valve containing element 30 is enlarged and this is accomplished by forming or providing an extension 61 which has communication with the passage 31. Within this extension 61 is arranged a piston 62 having a pisto`nrod'63 connected with a piston 64 that Aoperates in a cylinder 65. The supply pipe 39 for conducting fluid to the cylinder 34 and the tank4 sitioned that it will prevent any apprecia leaniount of the liquid from entering the extension 61 and the normal tendency of the yfluid pressure in the cylinder 65 behind the piston 64 is to hold the piston 62 in such a position.

When, however, the piston acts upon the trapped liquid in the cylinder 24 and the lower portion of' the pipe 29 and the adjacent portion of the passage 31, it willcause some of the trapped liquid to flow under a considerable pressure into the extension 6l to move the pistons 62 and 64 against the fluid pressure in the cylinder 65, thereby overcoming such pressure and permitting the space within which the trapped liquid is confined, to be temporarily and slightly enlarged, .with the result that the sudden shock or stress upon the crank shaftl and other portions of the press will be overcome.

As soon as the pressure upon the liquid in the cylinder 24 is increased suiliciently to overcome the pressure exerted upon the valve 33, the. latter will be unseated and the liquid will flow back to the tank or receiver 27. As soon as the pressure of the iiuid upon the pistons 64 and 62 is greater than the pressure upon the liquid, the pistons 64 and, 62 will be moved from the position shown in Figure 3, back to the position shown in Figure 1. -1

Ports or passages 68 and 69 may be provided respectively in the ycylinders 65 and extension 61 to permitl the escape of air and thereby not interfere with the operation of the pistons 62 and 64.

If desired a control valve 70 may be provided at any convenient point in the pipe 39 or extension 66.

By means of the control valves 41 and 67 the respective pressures in the cylinders 34 and 65 may be varied at will.

While the preferred form of the inventon has been herein shown and described, it is to be understood that various changes may be made in the details of construction and in the combination and arrangement of the several parts, within the scope of the claims, without departing from the spirit of this invention.

What is claimed as new is 1. In combination, a pressure pad, hydraulic means for resistingthe movement of the pad in one direction, said means, em-

' bodying a liquid and a piston element per-Y able upon the liquid `and means operating automatically at the time the piston starts to move against the stress of the liquid, to eliminate the shock to the actuating mechanism which would be caused by the sudden resistance of the liquid to the movement of the piston.

2. In combination, a pressure pad, hydraulic means for resisting the movement of the pad in one direction, said means embodying a liquid and a piston-element operable upon the liquid, variable resistance means for controlling the resistance pressure exerted by the piston upon the liquid,

and means operating automatically at the time the piston starts to move against the stress of the liquid, to eliminate the shock to the actuating mechanism which would be caused by the sudden resistance of the liquid to the movement of the piston.

3. In combination, a pressure pad, hy-

draulic means for resisting the movement of the pad in one direction, said smeans eniborlying a liquid and a piston .element operable upon the liquid, and fluid controlled means operable automatically at the time the piston starts to move against the stress of Vthe liquid, to eliminate the shock to the actuating mechanism which would be caused by the sudden resistance of the liquid to the 'movement of the piston.

4. In combination, a pressure pad, hydraulic means for resisting the movement of the pad in one direction, said means embodyingv a liquid and a piston element operable upon the liquid, variable resistance means for controlling the resistance pressure exerted by the piston upon the liquid, and fluid controlled means operable automatically at the time the piston starts to move against theA vstress of the liquid, to eliminate theshock tothe actuatin mechanism which would be caused by t e sudden resistance of the liquid to the movement of the piston. f

5. In combination, a `pressure pad, hydraulic means for resisting the movement of the pad in one direction, said means embodying a liquid and a iston element operable upon the liquid, uid pressure controlled means automatically operable at a predetermined time in the cycle of operation of the said pad to eliminate the shock to the movement of the pad which would be caused by the sudden resistance of the liquid to the movement of said piston, and lmeans :for varying at will the said uid pressure.

6. In combination, a pressure pad, hydraulic means for resisting the movement of the padin one direction, said means embodying a non-compressible liquid and a piston element operable upon the l1qu1d,

the cyc e of operation of thesaid pad to eliminate the shock to the movement of the pad which would be caused by the sudden resistance ofthe liquid to the movement o said piston, and means Jfor varying at Will the said fluid pressure.

7. In combination, a pressure pad, hydraulic means for resisting the movement of the pad in one direction, said means embodying a container' for the liquid and a piston operable upon the liquid, and means operable automatically to increase'the liquid containing area in the said container, ata predetermined time in the cycle of operation of the piston, to overcome the shock which would be caused by the sudden resistance of the liquid in said container to the movement ot' the piston.

8. In combination, a pressure pad, hydraulic means for resisting the movement of the pad in one direction, said -means embodying av container'for the liquid and a piston operable upon the liquid, and fluid pressure controlled means operable automatically to increase the liquid containing bodying piston,

area in the said container, at a predetermined time in the cycle of operation of the to overcome the shock which would be caused by the sudden resistance of the yliquid in said container to the movement of the piston.

9. 'In combination, a pressure pad, hy-

rdraulic means for resisting the movement of the pad in one direction, said means ema container for the liquid and a piston operable upon the liquid, fluid pressure controlled means operable automati- -cally to increase the liquid'eontaining area inl vthe said container, at a predetermined time in the cycle of operation of. the piston, to overcome the shock 'which would be caused by the sudden resistance of the liquid in said container to the' movement of the piston, and means for varying at will the said fluid pressure.

10. In combination', a pressure pad, hydraulic means for resisting the movement of the ad in one direction, said means embodying a container for the liquid anda piston operable upon the liquid, and means operable automatically to increase the liquid containing area in the saidv container, at a predetermined time inthe'cycle of operation of the piston, to overcome the shock which would be caused by the sudden resistance ofthe liquid in said container to the movement of the piston, the last said means. also operating automatically at a predetermined time in the cycle of operation of the piston'to restore 'the said container to the normal liquid containing area.

11. In combination, a pressure pad, hydraulic means for resisting the movement of the pad in one direction, said means embodying a liquid and a piston element operable u on the liquid, and means operating to eliminate the shock to the actuatingA mechanism which would be caused by the sudden resistance of the liquid to the movement of the piston.

12. In combinatiom a pressure pad, hydraulie means for resisting the movement o the pad in one direction, said means embodying a liquid and a piston element operable upon the liquid, and means operating at the time the piston -starts to move against thestress of the liquld, to eliminate the shock to the actuating mechanism which would be caused by the sudden resistance of the liquid to the movement of the piston.

In testimony whereof I have signed my name to this specification, on this 29th day of March, A. D. 1928.

FREDRIor-I J. RODE.

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