US2301838A - Hydraulic press - Google Patents

Description

Nov.'10, 1942. F. c. WILSON 2,301,838

HYDRAULIC PRESS Filed July 20, 1940 2 Sheets-Sheet 2 Fig.4.

INVENTOR Patented Nov. 10, 1942 UNITED STATES PATENT OFFICE HYDRAULIC PRESS Frank C. Wilson, Arcade, N. Y.

Application JulyZi), 1940, Serial No. 346,605

2 Claims.

This invention relates to improvements in hydraulic presses of the kind wherein a manually operable pump is availed of to develop the fluid pressures utilized in actuating the ram and, although not necessarily so limited, the invention contemplates a press in which the movement of the ram to and away from its work engaging positions and its actuation in light pressing operations are eiiected by a conventional handwheeln One object of the invention is to provide a novel construction and arrangement of the parts of the press whereby to obtain simplicity and compactness in design.

A further object is a press of the type generally described in which provision is made for minimizing dissipation of the working pressures, this object contemplating a construction where in such pressures tend to seat the pressure releasing valve.

A still further object is to provide a press in which the working cylinder is charged at all times and wherein the loading of the said cylinder occurs simultaneously with, and as an incident to, the adjustment of the ram to a work engaging position.

A still further object is to provide for facility in adjusting the table of the press.

The invention is illustrated in the accompanying drawings in which:

Figure 1 is a side elevation of press embodying the features of the invention.

Figure 2 is a horizontal section taken along line 2-2 of Figure 1.

Figure 3 is a fragmentary section taken along 7 which connect the upper ends of the standards and bars l3 which connect the lower ends thereof. p

The working cylinder, indicated at M, is

mounted between the cross-plates l2 substantially midway between the standards and above a table [5. The latter comprises a pair of plates l6 (Figure 2) which at one end are pivotally connected by bolts H to the opposite sides of a holder l8 and which at their opposite ends are pivotally connected by bolts H) to a holder 25 The said holders are similar and are slidable upon the standards H to enable the table 15 to be adjusted the proper distance below the ram 2! of the working cylinder, the table being supported in. its various positions of adjustment upon pins 22 which may be inserted in holes 23 formed in the standards. To facilitate adjustment of the table, handles 24 are provided upon the holders I8 and 2E) and at one end of the table the bolts l9 pass through horizontal slots 25 formed in the plates l6. As a result, the table may be elevated or lowered, one end at a time, without undue effort by a single operator, the slots 25 permitting the holders l3 and 20 to move away from and toward one another as the distance between them varies.

The piston 26 (Figure 4) of the working cylinder is suitably secured to a reduced shank portion 27 of the ram 2| which has a lower end movable through a guide opening 23 formed in the lower head 29 of the cylinder. Along its back the ram is formed to provide a gear rack 30, the teeth of which mesh with a pinion 3! which is fixed to the inner end of a shaft 32. The outer end of the said shaft is journaled in a bearing 32a, which is carried by one of the standards H, and carries a handwheel 33 which is available to move the ram toward and away from the' table l5 and to operate the ram when only light pressures are required.

The fluid utilized in operating the ram is contained in a tank 34 which is mounted upon the top of the working cylinder, the said tank having a closure 34a which is adapted to permit air to readily enter and leave the tank. The fluid is withdrawn from the tank and forced into the cylinder M by a pump 35. The cylinder 35 of the latter is preferably formed integrally with the working cylinder and includes a plunger 31 which is movable in a bore 38, the said bore communicating with the tank 34 through an inlet passage 39 and with the working cylinder through an outlet passage 40. A spring loaded check valve 4| which normally closes th'e'passage 39 opens during downward strokes of the plunger 31 to permit fluid'to enter the pump and a spring loaded check valve 42 which normally closes the passage 49 opens during upward movements of the plunger to permit the fluid to enter the work ing cylinder. The plunger 31 is operated by a handle 43; The'latter is formed with a hub 4a which fits over, and is suitably secured upon, 'a stub'shaft '45 carried by the lower end of the working cylinder, an extension 46 ofthe hub being connected by a link 41 to the lower end of the plunger.

The pressure in the working cylinder is released by: and the fluid therein is permitted to return to the tank through a valve 48 which is mounted in an inverted cup-shaped member 49, it being noted that the said valve is so designed that the pressure of the fluid in the working cylinder urges it against its seat. Sealing of the outlet port is thus insured, thereby preventing dissipation of the working pressures as a result of leakage. The member 68 is fitted in an opening 58 formed in the top of the cylinder, extends into the tank and is formed with passages 5| through which the working cylinder communicates with the tank.

The valve :28 may be opened by a wheel 52 which is fixed to the outer end of a cylindrical element 53. The said element is rotatably sup ported in a horizontal bore formed in the lower head of the working cylinder and is formed to provide outer and inner gear segments 54 and 55, respectively. The former meshes with a rack 58 which is movable lengthwise in a vertical bore formed in the head 28 and which is connected by a rod 5'! to the outer end of an arm 58, the inner of the said arm being pivotally connected to an extension of a ring 59 which is suitably secured upon a neck portion of the member 49. Adjacent its pivoted end the arm 53 overlies the stem 86 of the valve 48, the latter being normally held closed by a spring 61. The valve may be opened by rotating the wheel 52 clockwise, movement of the wheel in this direction causing a downward movement of the rod 51 and a corresponding movement of the outer end of the arm 58.

Means is provided for cracking the pressure in the working cylinder in order to facilitate opening of the valve 58. The said means includes a spring loaded ball valve 62 which normally closes an axial passage 63 through the valve 58 and the stem 68 thereof, the said passage providing communication between the working cylinder and the tank. A pin 64 which is located in the passage 63 and which is of a smaller diameter than that of the passage rests upon the valve 62. Its upper and extends above the upper end of the stem 68 of the valve 48 and supports the arm 58 so that the forked outer end thereof which straddles the rod 51 is located under and in close proximity to a head 65 on the rod. It will thus be apparent that upon operation of the wheel 52 to open the valve 58 in the manner described the arm 58 will first open the valve 52 to permit an initial escape of fluid from the working cylinder through the passage 53 and thereby crack the pressure in the cylinder. The efiort required to unseat the valve 48 as the arm 58 thereafter engages the stem 68 and moves .it downward is thus substantially reduced and opening of the valve against the seating action of the fluid is facilitated.

As a precautionary measure the invention contemplates the automatic release of the pressure 7 in the working cylinder in the event that the ram approaches a predetermined safe limit in its working stroke. To this end a rack 56 (Figures 4 and 6) which is movable lengthwise in a vertical bore formed in the head 29-is provided, the teeth of the rack meshing with the inner gear segment 55 formed on the element 53. The upper end of the rack extends into the working cylinder and into the path of the piston so that it will be engaged by the piston when the latter approaches the limit of its working stroke and will be moved downward. The resultant clockwise movement of the element 53 is transmitted by the rack 56 and rod 5'! to the arm 58 andthe pressure in the working cylinder will, therefore, be automatically released in the manner described.

In the use of the press, assuming the working cylinder to be charged and the wheel 52 to be adjusted to a position corresponding to the closed position of the valve 48, the handwheel 33 may be turned to adjust the ram toward the work. During this movement of the ram the valve 48 opens in response to atmospheric pressure upon the fluid in the tank and against the action of the spring SI and fluid from the tank enters the working cylinder, the latter being charged as the ram is moved to engage the work. Upon operation of the pump, therefore, the development of pressure within the working cylinder begins with the first upward stroke of the handle 43. When the pressing operation has been completed the wheel 52 may be turned to release the pressure in the working cylinder in the manner described and permit the ram to be elevated to the desired position.

Apart from the advantages heretofore noted the press described has the further advantage that it is extremely simple and compact in design, it being noted in this connection that all piping is eliminated. A still further advantage obtained is that the operator can stand in a position, during operation of the pump, which will enable him to keep a close watch upon the work and the progress of the ram.

I claim as my invention:

1. A hydraulic press including a ram, a working cylinder, a fluid container, a pump for with drawing fluid from said container and for forcing it into said cylinder, means for permitting the return of said fluid from said cylinder to said container to release the pressure in said cylinder, said means including a normally closed valve, a lever for opening said valve, a rod having one end connected to said lever and one end which is formed to provide a gear rack, a manually rotatable element for actuating said rod to open said valve, said element having two pinion sections, one of which meshes with said gear rack and a rack element which meshes with the other of said pinion sections, one end of said rack element being located in the path of said ram, whereby when the latter approaches a predetermined safe limit in its working stroke it moves said rack element lengthwise to actuate said rod and automatically open said valve.

2. A hydraulic press including a ram, a working cylinder for operating said ram, afluid container supported on said cylinder, a pump for withdrawing fluid from said container and for forcing it into said cylinder, means for permitting the return of said fluid from said cylinder to said container to release the pressure in said cylinder, said means including a normally closed valve, a pivotally mounted lever in said container for opening said valve, a rod having an upper end which extends into said container and which is connected to saidlever and a lower end which is formed to provide a gear rack, a manually rotatable element for actuating said rod to open said valve, said element having two pinion sections, one of which meshes with said gear rack and a rack element which meshes with the other of said pinion sections, one end of said rack element extending into said cylinder and into the path of said ram, whereby when the latter approaches a predetermined safe limit in its working stroke it moves said rack element lengthwise to actuate said rod and automatically open said valve.

FRANK C. WILSON.

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