US764521A - Hydraulic press. - Google Patents

Description

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S. S m RP WG 0I RL GU RM D Y H L 2 5, 4 6 7 m N APPLICATION FILED NOV. 3, 1903.

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nz/ NESS/fs i UNITED STATES Patented July 5, 1904.

PATENT OFFICE.

EDWARD OROWE, OE SHEEFIELD, ENGLAND, ASSIGNOR OF ONE-HALF TO DAVY BROS., LIMITED, OF SHEFFIELD, ENGLAND, AN INCORPORATED COMPANY.

HYDRAULIC PRESS.

SPECIFICATION forming part of Letters Patent No. 764,521, dated July 5, 1904.

Original application iiled Juno l5, 1903, Serial No. 161,538. No. 179,698.

To al?, whom t may concern,.-

Be it known that I, EDWARD CROWE, engineer and chief draftsman, a subject of the `King of Great Britain, residing at Birchholrn,

Bushey Wood, Totley Rise, Sheffield, England, have invented certain new and useful Improvementsin Hydraulic Presses, of which the following is a speeiiication.

This invention relates to hydraulic presses 1 o for forging and for other purposes-such, for eXample-as bendingand testingarmor-plates, Hanging, and the likein which the power for lifting the press-head is supplied from an accumulator or other source independent of i 5 that from which the power is derived for causing the press-head to perform its work.

The invention has for its object to effect economy of time and power, and so increase the speed of working and the efficiency of the ,zo press. This end is attained mainly by the provision of means whereby the idle descent of the press-head onto its work may be l effected quickly and by gravity alone and whereby the power of the pumps is caused to come into 2 5 action automatically immediately the tool earried by the press-head encounters the work.

The present application is a division of my copending application, Serial No.161,538,iiled June 15, 1903.

Reference is to be had to the accompanying drawing, which shows in an elementary form the improved apparatus and arrangement of parts, the two portions of the iigure being drawn to different scales.

The press comprises a main cylinderA and ram B (one or more) for imparting the Working stroke to the press-head and lifting-cylinders O and pistons D for imparting the return stroke. The pipe connections with these 40 cylinders are controlled by valves arranged to so operate that during the idle descent of the press-head the main and lifting cylinders can be connected at the same time with their respective exhausts in such manner that the 4 5 main cylinder A being permitted to draw from the exhaust-tank will descend freely by its own Weight, the main pumps meanwhile either running light or being out of work,

Divided and this application filed November 3, 1903. Serial (No model.)

while during the working portion of the pressstroke pressure can be supplied to the main cylinder A and exhausted from the lifting'- cylinders O and on the return stroke can be supplied to the lifting-cylinders O and exhausted from the main cylinder A alternatively.

Between the main cylinder A and the eX- haust-valve F there is provided a self-closing by-pass suction-valve Gr, which,while permitting the main cylinder to draw from the exhaust during the free descent of the press- 6o head, will be closed immediately the descent of the main ram is checked in consequence of the tool meeting the work, so that pressure then brought to bear on the main ram will cause its descent to be continued, but at a slower speed.

The upper end of the main cylinder A is connected by a pipe a with the valve-box of the valves Gand F and through a constantlyopen annularl passagef around thelatter valve 7o with the delivery-pipe p from the pumps P.

The exhaust-valve F is a piston-valve of two diameters, the upper portion, which works in the cylinder f3, being of larger diameter than the valve-face itself, so that the valve, which is normally held closed by pressure acting in cylinder f3' on the upper surface of the valve-body, will be opened by pressure acting upon the annular shoulder, representing the difference between the two diameters 8o when the cylinder f is exhausted. This cylinder is connected by the pipe f2 with an aecumulator or other source of auxiliary hydraulie power, which also supplies power to the lifting-cylinders C by way of the pipe c and branch pipes c.

H is a slide-valve controlled by means of a lever-handle, as shown, and connected with both pipes c and f2 and also with an exhaust in such manner that according as the valve H is moved to the one or the other end of its stroke the supply of power will be admitted to pipe c to lift the press-head and 'at same time will be exhausted from pipe f to permit the main exhaust-valve F to open, or, alternatively, the supply of power will be eX- hausted from pipe c to allow the press-head to descend and at same time will 4be admitted to pipe f2 to close the Valve F.

The action is as follows: When the liftingcylinders C are connected to the exhaust of the Valve H, accumulative pressure will be admitted to the cylinderfa of the main exhaust-valve F, which will be closed, and the press-head will descend by its own weight, the main cylinder A drawing water through the by-pass suction-Valve Gr until the presshead tool meets the'work, whereupon the valve G will close and the movement of the presshead will be continued at a slower speed under the power of the pumps. To lift the press-head, the valve H is shifted, so as to admit accumulator-pressure to the liftingcylinder C and at the same time connect the cylinder f3 of the main exhaust-valve F with its exhaust to allow the valve F to be opened by the pressure acting on its shoulder, and

thus permit water from the main press-cylinder A to flow back to the exhaust J. If

the pumps P are kept running, the water thereby supplied will return to the exhaust J through the open Valve F.

I claim- In a downwardly-acting hydraulic press wherein working and lifting rams are coning operated by pressure from an auxiliary source oi' supply independent of that whence power is supplied to the working ram, the combination of a valve for Controlling the exhaust from the cylinder of the working rain, the body of said exhaust-valve beingl formed as a plunger of two diameters fitted to work in a cylinder wherein it may be acted upon by the working pressure in a direction to open the Valve and by the auxiliary pressure in a direction to close the valve; a separate suction-valve on a by-pass to the exhaust- Valve adapted to be held open by the liow of water from the exhaust to the cylinder of the working ram while the exhaust-valve is closed during the idle part of the descent of the press-head and to close automatically when said flow ceases in consequence of such idle descent of the press-head being arrested; and a hand-operated valve adapted to control the distribution of auxiliary pressure to and its exhaustion from the cylinders of the liftingrams and that of the exhaust-valve plunger alternatively, substantially as specified.

EDWARD CROVE. Witnesses:

BAIN L. CAMPBELL, LUTHER J. PARR.

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