US1742877A - Sheet-metal press - Google Patents

Description

n 7, 1930. F. J. RODE ET AL 1,742,877

SHEET METAL PRESS Filed March 18; 1929 3 Sheets-Sheet 1 Jan. 7, 1930. F. J. RODE ET AL 1,742,877

SHEET METAL PRESS Filed March 18, 1929 3 Sheets-Sheet 2 Jan. 7, 1930. F. J. RODE ET AL 1,742,877

SHEET METAL PRES S Filed March 18, 1929 S Sheets-Sheet 5 Patented 1.1.... 7, 1930 UNITED STATES PATENT OFFICE FRIEDRICH T. RODE AND JOSEPH HARRY J'OCHUM, 31%., OF CHICAGO, ILLINOIS SHEET-METAL PRESS Application filed March 18, 1929. Serial No. 347,752.

This invention relates to improvements in sheet metal presses of the type embodying a blank or work holding member that oo-operates with a movable member to clamp or hold the work therebetween while it is being shaped or formed over a forming die, the

- work holding member being resisted in its movement in one direction by a cushioning dev1ce.

One of the serious disadvantages of many cushioning devices for sheet metal drawing dies is that they follow the movable die or ram on the upward movement thereof, with the result that there will be created what is commonly known as back lash or back kick which not only injures the machine and shortens the life thereof but is in many other respects objectionable.

It is one of the objects of the present invention to provide improved means for controlling the upward or return movement of the work holding member, and which movement operates to lock or hold the work holding member against return with the movable die or ram, and improved means for releasing or allowing the work holderto return at a predetermined time in the cycle of operation of the press and which latter means will be operated or controlled from a movable part 20 of the press.

A further object is to provide an improved locking means embodying a dash pot construction, the movable memberthereof being operatively connected with the work holder 5 and operating to lock the movable member thereof against movement in one direction, and improved means for rendering the dash pot active and inactive.

To the attainment of these ends and the so ly in section and partly broken away of a accomplishment of other new and useful obsheet metal press constructed in accordance with the principles of this invention.

Figure 2 is an irregular sectional view taken on line 2-2, Figure 1, and showing the a parts in one position, that is with the work holder locked against return movement with the ram.

Figure 3 is a view similar to Figure 1 on an enlarged scale and with parts omitted showing the work holder released so as to permit the pressure pad to return to its normal position.

Figure dis an enlarged detail view of the controlling cam mechanism.

Referring more particularly to the drawings the numeral 10 designates generally the bed of a press, 11 the uprights, 12 a reciprocable ram, 13 a movable die member, 14 a stationary die member over which the work is shaped, 15 a blank or work holding ele; ment which co-operates with the movable die 13, 16 pins which support the work holder 15 and which passloosely through the bed 10 of the press; 17 a pressure pad upon which the pine 16 rest and 18 cushioning devices which are mounted upon suitable supports 19 below the body of the press and held in position by means ofhanger rods or members All of the above referred to parts are of the ordinary and well known construction and while there is illustrated in the drawings a cushioning device of the fluid pressure type,

it is to be understood that this invention is applicable to any form of cushioning means which yieldingly resistthe movement of the pressure pad 17 in one direction.

Supported in any desired or suitable manner preferably below the cushioning devices at 24 with the pressure pad 17, a lock nut 25 being provided, if desired.

Leading from the bottom of the cylinder 21 on one side of the piston 22, is a passa e 26 which has communication preferably by means of a pipe 27 with a valve casing 28 and leading also from the top of the cylinder 21 on the other side of the piston is a passage 29 which has connection by means of a pipe 30 with the valve casing 28. p Within the valve casing is a valve 31 which is adapted to control the passage of the liquid in the cylinder 21 from one side to the other side of the piston 22. Thus when the valve 31 is opened and the piston 22 is reciprocated in the cylinder 21 the liquid will flow from the cylinder through the respective passages to the other side of the piston.

In order therefore to control the movement of the piston 22 in the cylinder 21, it is only necessary to check or control the flow of the fluid from one side to the other side of the piston. To that end the valve 31 is provided and the valve is adapted to be seated by means of a spring 32 to close the passage and thereby interrupt the passage of the fluid from one side to the other of the piston.

The spring 32 operates to normally close the valve and the valve is adapted to be opened a ainst the stress of the spring 32 in any suita le manner preferably by means of an arm 33 mounted upon a rock shaft 34 which in turn is supported by means of a bracket 35.

Connected with the rock shaft 34 is another arm 36 and connected with this arm 36 is a rod or link 37. The free end of the rod or link 37 is pivotally connected as at 38 with a reciprocable member .39 movable in a suitable guide 40.

Connected with a movable part of the press such as the crank shaft 41 which reciprocates the ram 12, is a cam 42-having a shoulder 43. Carried by the end of the reciprocating member 39 is an anti-friction roller 44 which op-.

crates upon the cam 42 and the member 39 is preferably provided with a slot 45 through which a member 46 carried by the cam 42' passes so as to guide the upper end of the member 39 and at the same time permit it to have a free movement with respect to the cam. The cam 42 is carried by a member 47 that is connected by means of screw and slot con nections 48-49 with the shaft so as to permit the member 47 and also the cam 42 to be adjusted with respect to the shaft 41 and thereby vary or control the time of operation of the shaft 30 by the cam. I

The cylinder 21 and piston 22 constitute a dash pot in which a predetermined supply of liquid is maintained and this supply is sufficient to substantially fill the cylinder, the llquld being supplied from any suitable source such as a tank '50, through a pipe 51 which is connected with the pipe 27. The liquid in the tank 5Q'may be subjected to pressure supplied through a suitable pipe 50 from any suitable source not shown. A check valve 52 is arranged in the pipe 51 that permits the liquid to flow in one direction to the cylinders 21 from the tank 50, but will prevent it from flowing back into the tank 50.

If desired, a spring controlled pressure relief valve 53 may be provided and is located in a pipe 54, which latter has communication with the tank 50 preferably through the pipe 51.

It is thought that the operation of the device will be clearly understood from the foregoing, but briefly stated it is as follows.

When the parts are in their normal position, to-wit: as shown in Figure 3, the pressure pad 17 will be in engagement with the bottom of the bed plate 10 and the work holding element 15 will be substantially flush with the top of the stationary die 14, while the ram will be in its uppermost position.

At this time the cam 42 will be positioned so that the member 39 and rod or link 37 will be raised, causing the arm 33 on the rock shaft the stress of the spring 32, during the major portion of the operation of the press.

As the ram 12 descends the work 55 will be formed over the die 14 in the usual manner, and during the descending movement of the pressure pad 17 and the ram the cam 42 will still operate to cause the valve 31 to be maintained open. The valve will be held open until just at the time that the pressure pad 17 reaches the limit of its lowermost movement, which will also be at the time that the piston 22 reaches the limit of its lowermost movement in the cylinder 21.

At this time in the cycle of operation of the press the cam 42 will have assumed the position shown in Figures 2 and 4, that is so that the shoulder 43 of the cam will be positioned so that the anti-friction roller will drop to the low portion of the cam causing the member 39 and rod or link 37 to be lowered thereby rocking the shaft 34 to move the arm 33 to the position shown in Figure 2 so that the valve 31 will be closed by the action of the spring 32. Thi spring 32 also assists in causing the anti-friction roller 44 to drop off of the high portion of the cam. Immediately the valve 31 is closed the passage of the fluid from the top side to the lower side of tl e piston 22 will be arrested and as the fluid on the top side of the piston cannot bottom of the cylinder 22 which will in turn lock the pressure pad 17 against return movement. The lockingof the piston 22 is determined by the shape of the cam 42 and it will therefore be manifest that this cam may be so designed that the piston 22 may be then be free to rise in the cylinder 21 by rea-.

son of the fact that the fluid above the piston may then escape through the passage 29, pipe 30, valve casing 28, pipe 27, passage 26, to the lower side of the piston.

While the preferred form of the invention 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 a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, a dash pot operatively connected with said pad'and operable to lock said pad against return movement, and means operating automatically to control the locking and unlocking operation of said dash pot.

2. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, a dash pot operatively connected with said pad and operable to lock said pad against return movement, and means responsive in its operation to a movable part of the press for automatically controlling the locking and unlocking operation of said dash pot.

'3. In a press for drawing sheet metal and the.like, cushioning means, a pad movable against the resistance of said cushioning means, means for temporarily locking said 'pad against return movement, said locking means embodying a cylinde'r,-a piston movable therein, a fluid substantially filling the cylinder, means for transferring the fluid from one side to the other side of the piston to permit a relative movement of the cylinder and piston, and means for temporarily interrupting such transfer of the fluid to prevent such relative movement of the piston and cylinder.

4. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, ,a dash pot for temporarily locking the pad against return movement, said dash pot embodying a cylinder and piston, a passage for transferring fluid from one to the other side of the piston, a normally open valve for controlling said passage, and means for operating the valve to close said passage.

' 5. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, a dash pot for temporarily locking the pad against return movement, said dash pot embodying a cylinder and piston, a passage for transferring fluid from one to the other side of the piston, a normally open valve for controlling said passage, and means operating automatically at a predetermined time in the cycle of operation of the press for causing a quick closing action to be given to said valve to close said passage.

6. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, a dash pot for temporarily locking the pad against return movement, said dash pot embodying a cylinder and piston, a passage for transferring fluid from one to the other side of the piston, a normally open valve for controlling said passage, and means responsive in its operation to a movable part of the press for causing the valve to temporarily close said passage in the cycle of operation of the press.

7 In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, means for temporarily locking the pad against return movement, the last said means embodying a cylinder and piston relatively movable one with relation to the other and one of which is connected with said pad, the other being maintained stationary, a predetermined supply of fluid filling the cylinder,

means for directin the fluid back and forth to opposite sides 0 the piston to permlt such relative movement, and means operating automatically to control the last said means to prevent relative movement of the cylinder and iston.

8. n a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushion, a relatively movable piston and cylinder one of which is connected with said pad, the other bein maintained stationary, a predetermined supp y of fluid filling said cylinder, a passage for directing the fluid from one side to the other of the piston to permit such relative movement, a valve for controlling said passage, and means operating to cause said valve to be closed during only a predetermined portion of the cycle of operation'of the press to prevent such relative movement and thereby temporarily lock the said pad against return movement. I

9. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushion, a relatively movable piston and cylinder one of 5 which is connected with said pad, the other being maintained stationary, a predetermined supply of fluid filling said cylinder, a passage for directing the fluid from one side to the other of the piston to permit such relative movement, a valve for controlling said passage, and means operating to cause said valve to be closed'during only a prede termined portion of the cycle of operation of the press to prevent such relative movement and thereby temporarily lock the said pad against return movement, the last said means embodying a quick acting cam device.

10. In a press for drawing sheet metal and the like, cushioning means, a pad movable against the resistance of said cushioning means, means for temporarily locking sai pad against return movement, said locking means embodying a cylinder, a piston movable therein, a fluid substantially filling the g5 cylinder, means for transferrin the fluid from One'side to the other side 0% the piston to permit a relative movement of the cylinder and piston, means for temporarily interrupting such transfer of the fluid to prevent such re ative movement of the piston and cylinder, and a fluid pressure relief valve for said look- 111 means.

11 testimony whereof we have signed our names to this specification, on this 12th day of March, A. D. 1929. I i

e FREDRICH J. RODE.

J. HARRY JOOHUM, JR.

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