US2319964A - Hydraulic press - Google Patents

Description

F. C. WILSON HYDRAULIC PRESS May 25, 1943.

Filed- Juiy 20, 1940" 3 Sheets-Sheet '1 INVENTOR May 25, 19.43. F. c; WILSON I 9,

' HYDRAULIC PRESS Filed July 20, 1940 3 Sheets-Sheet 2 f ak? all ($072 BY J W ATTORNEY Patented May 25, 1943 UNlTED STATES PATENT OFFICE HYDRAULIC PRESS Frank C. Wilson, Arcade, N. Y. A

Application July 20, 1940, Serial No. 346,606 8 Claims. (01. 277-43) 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 effected :by a conventional handwheel.

One object of the invention is to provide a press in which the ram will remain in any position to which it may be adjusted between the limits of its range of movement, this object contemplating a construction wherein the fluid container is located at a lower elevation than the working cylinder and wherein the ram is balanced in its various free positions by the column of fluid which, except for atmospheric pressure, would otherwise be free to flow back into the container under the influence of gravity.

A further object is to provide a press wherein moderate working pressures may be developed rapidly without unduly increasing the effort required to operate the pump when high pressures are called for.

A still further object is a novel design and arrangementcf the parts of the press whereby high strength and rigidity in construction are obtained.

The invention is illustrated in the accompanying drawings in which:

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

Figure 2 is a detail section taken along line 22 of Figure 1.

Figure 3 is a fragmentary section taken along line 3-3 of Figure 6.

Figure 4 is a. side elevation of the press.

Figur 5 is an enlarged vertical section taken along line 55 of Figure 1.

Figure 6 is an enlarged vertical section taken along line 66 of Figure 1.

Figure 7 is a detail section taken along line 1-1 of Figure 6.

Figure 8 is asimilar section taken along the same line but showing different positions of the parts.

Figure 9 is a section through the relief valve and actuating mechanism therefor, the valve being shown seated.

The frame of the press which, as illustrated, is rectangular, is supported upon feet l2 and includes standards l3 of channel cross-section, cross plates M which connect the upper ends of the standards and bars I 5 which connect the lower ends thereof.

The working cylinder, indicated at I6, is mounted between the cross plates l4 substantially midway between the standards and above a table II. The latter comprises a pair of plates [8 which are connected by bolts I9, which overlie the flanges 20 of the standards and which rest upon pins H. Series of holes 22 are formed in the flanges 20 for accommodating the pins 2!, whereby to provide for the support of the table at various elevations. The table may be raised or lowered, as required, by a Windlass 24 which is mounted upon one of the standards l3. The drum of the Windlass carries two cables 25 and 26, the latter passing over pulleys 21, 28 and 29 and being connected by one of the bolts l9 to the far end of the table and the other passing over a pulley 30 and being connected by one of the said bolts to the near end of the table. In order to support the table at the desired elevation While the location of the pins 2| is being changed a ratchet 3| is preferably provided for engagement With a toothed ring 32 carried by the drum of the Windlass.

The ram 23 (Figure 5) is located co-axially of the working cylinder. It extends through an open,- ing 33 formed in the lower head 34 thereof and one side is formed to provide a gear rack 35. The teeth of the latter mesh with a pinion 36 which is mounted in the head 34 and which is adapted to be driven by a shaft 31 (Figure 1), the outer end of which is journaled in a suitable bearing 38 (mounted on one of the standards l3) and carries a handwheel 39. The spokes 49 of the handwheel are preferably adjustable lengthwise in the hub 4| in order to enable the desired leverage to be obtained, it being understood in this connection that in the use of the press in light pressing operations the ram may be actuated by the handwheel. The upper end of the ram is formed with a reduced shank 42 to which the piston 43 of the working cylinder is connected, the said shank being formed with a longitudinally extending slot 44. The lower end of the latter accommodates a key 45 which is adapted to prevent angular movement .of the piston upon the ram.

The oil or other fluid medium which actuates the piston 43 is withdrawn from a container 46 (Figure 4) by a pump 41 and is forced through a supply line 48 into the working cylinder at the upper side of the piston 43, the pump being carried by the container and the two being mounted as a unit upon one of the standards I3. The

container, as best shown in Figure 6, includes a cover-piece 49 and is formed adjacent its bottom with an outlet opening 50 which communicates with an inlet chamlber formed in the body 52 of the pump. The inlet chamber 5| in turn communicates through ports 53 with parallel bores 54 which are formed in the pump body to accommodate dual plungers 55 and 56, the bottoms of the said bores being formed to provide seats for check valves 51. Adjacent its lower end each of the bores 54 communicates through a laterally extending duct 58 (Figure 3) with a chamber 59, the said chamber having an outlet 60 to which the pipe line 48 is connected and.

the entrances thereto being formed to provide seats for check valves 6|. Movement of the latter away from the said seats is limited b-ya pin 61a. 7

The upper end of the plunger 55 is pivotally connected to ahandle 62 which in turn is pivotally connected to the cover-piece 49of the container by a link 63, a bracket '64 which is secured to the container adjacent the cover-piece providing an upper guide for the plunger. A yoke 65 is fixed to the plunger 55 by pins 66 in such relation to the bracket 64 and the body of the pump as 'tojpermita full stroke of the plunger. The said yoke is formed with a socket 61 for accommodating the upper end'of the plunger 56 and carries a key "68. The body of the latter is cylindrical; occupies abore which extends crosswise of the socket 6'! and is cut away as at 69; it is rotatable in one direction so that it enters an annular recess Tl (Figure '7) formed in the upper end oi: the plunger 56; and it is rotatable in the opposite direction so thatitmoves out of the said recess (Figure 8) The two limits of the angular movement of the key are determined by a stoppinjll (Figure 6)ww.hich also serves to hold the key. againstlengthwise displacement. It will thus beapparentjthat thekey may be adjusted tolock the plunger'56 to the yoke so that both plungers canbe operated; simultaneously or to disconnect the plunger 56 from the yoke so that the plunger .55 can be operated alone. In the latter event it will be noted that during each downward stroke oftheplunger 55 theplunger 56 will move toward the bottom of the socket 61 in the yoke While during, each upward stroke the plunger 56 will be partially withdrawn from the socket.

Any air which'is trapped in the latter during the downward strokes, of the plunger 55 may escape through a vent! la. 1

-A return pipe 12 which is connected to the supply line .48 ntersvthe container 46 through the coverpiece 49. and the lower end thereof, whichis immersed in the fluid in the container, carries a; body 13. The latter is hollow, providing a valve chamber 14 and being formed in the bottomwall with an opening15 through which the chamber communicates with the interior of the container! "A ball; valve I6 normally closes the opening 15, as bestshown in Figure 9.

r In the operation' of the press (assuming that the table -l-l7is properly adjusted and that the working cylinder is charged) the handwheel 39 is rotated to move the ram into engagement with'the, work. As this occurs the downward movement of. the, piston 43 causes fluid to be drawn from the container 46 in such an amount that the' "working cylinder will remain fully chargedithe check valves ofthe pump and the ballfvalve- '16 openingto permit fluid to enter the supply line through the pump and the return pipe 12. When the downward. movement of the ram is arrested as the latter engages the work these valves close automatically. The pump is then operated to develop the desired pressure. The working cylinder being fully charged at this time the development of such pressure begins with the first downward stroke of the handle 62, the check valves 51 opening during the upward strokes of the plungers 55 and 56 to permit fluid to enter the bores 54 and closing during the downward strokes of the plungers as the check valves 6| open to permit the said fluid to enter the supply line 48. Preferably the key 68 is adjusted to connect the p-lungers for simultaneous movement until the eiiort required to operate the pump begins to be excessive. The key may then be adjusted to disconnect the plunger 56 so that the plunger 55 only is thereafter operated in obtaining such additional pressure as may be required. This procedure has the advantage that relatively low or moderate pressures may be dev-eloped rapidly while at the same time provision is made for developing relatively high pressures without undue efiort.

In order to prevent overtravel of the ram in its working stroke with possible attendant injury to the press the piston 43 carries a depending tube 11 (Figure 5) which communicates through a lateral passage 18 and the upper part of the slot 44 with the high pressure side of the cylinder. The passage through the tube, however, is normally closed by a ball valve 19 which is held seated by a spring 80, the latter being arranged within the upper end of the tube and acting against an upper Wall of the passage 18. The actuating means for the valve 19 includes a stem 8| which is carried by a cross-pin 82, the said cross-pin extending through elongated slots 83 formed in the lower end of the tube 11 and carrying a sleeve extension 84. The parts are so designed that when the piston 43 approaches the limit of its working stroke the sleeve extension 84 will enter a well 85 which is formed in the head 34 and contact a sealing element 86 of fiber or any other suitable material. As the downward movement of the sleeve extension is arrested and the tube I1 continues such movement the stem 8| lifts the valve 19 off its seat against the action of the spring 80. Fluid is thus permitted to escape from the high pressure side of the working cylinder, the said fluid passing through the tube 11, entering a duct 81 in the head 34 through an opening formed in the sealing element and being conducted by a pipe 88 to the container 46. The pressure of the fluid medium within the working cylinder is thus automatically relieved and possibility of injury to any of the parts of the press is avoided. The construction described has the further advantage that the fluid which is permitted to escape in the manner described is returned directly to the container and any possibility of its accumulating in the lower part of the working cylinder or its leaking through the guide opening 33 in the lower head is eliminated.

In the normal operation of the press the pressure in the working cylinder is released upon completion of the working strokes of the ram by operation of a control lever 89. The latter is fixed to a shaft 90 which is mounted in the coverpiece 49 of the fluid container and carries a gear segment 9| (Figure 6) which meshes with a rack 92. The latter is axially movable in a bore which is formed in the cover-piece and the teeth thereor are annular; andits lower-endwhich is tubular and internally threaded; is screwed upon the upper end of a rod 93, the lower end of which is pivotally connected to an arm: 94. The said, arm is pivotally connected. to a depending extension 94w which isv formed or provided upon the body rack may be screwed and unscrewed upon the rod 93. The rack is held in the position to which it is adjusted by a sleeve 99, the said sleeve having pointed ends I013 which enter notches formed in, and at opposite sides of, the rack. The sleeve is biased toward the rack by a spring; IIJI which is arranged under compression upon the rod 93 between the sleeve and a pin I02. Rotational movement of the sleeve upon the rod is-prevented by a pin I93, the sleeve being slotted as at I94 to permit its axial movement upon the rod. The lower end of the push pin 95 terminates. above and in spaced relation with respect to the bridge portion of a strap I which is carried by the arm 94.

The control lever 89 normally occupies the position shown in Figure 4 in which a finger I06 on the shaft 90 engages a stop I01 and in which the ball valve I6 is permitted to occupy its seat.

To release the pressure in the working cylinder the control lever is moved ina counterclockwise direction until a finger I08 which is carried. by the shaft 90 engages the stop I01 (see Figure 6). During this movement of the control lever the rod 93 is lifted as is the outer end of the arm 94. As the latter is moved toward the body I3 an adjustable element I 99 lifts a push pin I II] which is movable lengthwise in a bore III formed in the body I3, the stem of the push pin in turn lifting a ball valve 2 I2 off its seat I I3 against theaction of a ballast pin H4 which occupies a bore H5, thereby to permit a small amount of fluid to escape from the chamber I4 through a port H6 and the bores H5 and I H into the container. The pressure in the chamber I4 is thus cracked and the spring .91 which has been compressed between the arm 94 and the ball valve I6 is thereupon operative to lift the latter off its seat and hold it in the position shown in Figure 6 to permit fluid from the supply line 48 to discharge into the container through the return pipe I2. If the ball valve IB should become stuck to its seat so that the spring 91 is not strong enough to unseat it when the control lever is operated in the manner described, the bridge portion of the strap I 95 will engage the lower end of the push pin 95 and positively actuate the latter as the arm 94 approaches the upper limit of its range of movement.

In order to prevent the development of working pressures higher than those for which the press is designed means is provided for automatically releasing a portion of the fluid under pressure when such pressure exceeds a predetermined limit. The said means includes a relief valve H'I (Figure 6) which is carried in a sleeve I I8. The latter is screwed into a threaded opening formed in the body I3 and is formed with an extension H9 which overlies the ball valve I6 and serves to limit the upward movement of the valve in. response to the. action of the push pin 95, The valve III is formed with one or more grooves I20 through which fluid from the chamber I4 may escape when the valve opens against the action of the spring I21, the said fluid escaping into the container 46 through an opening in a plug 122' which is screwed into the end of the sleeve II 8 to hold the spring I-2I under the proper compression.

It willrbe-noted that the container 46 is located at a lower elevation than the working cylinder; that the valve I6, in addition to the check valves of the pump, will open automatically, to permit the working cylinder to be charged as the ram is advanced toward a work engaging position by the handwheel; and that when the control lever 89 is operated to release the pressure in the working cylinder it need not necessarily be restored immediately to its original position to. close the valve I6. In any event, however, the ram will always remain in any free position to which it may be adjusted between the limits of its range of movement, this result being obtained by utilizing as a counterbalance the column of fluid which, except for atmospheric pressure, would otherwise be free to flow back into the container under the influence of gravity.

I claim as my invention:

1. Mechanism for controlling the release o fluid under pressure including a main valve, a pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, and means for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves ofi their respective seats, the stem which actuates the pressure cracking valve being located closer to said pivot than the stem which actuates said main valve, whereby the greatest leverage is applied to the pressure cracking valve while maximum movement is transmitted to the main valve.

2. Mechanism for controlling the release of fluid under pressure including a main valve, a

- companion pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, means for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves off their respective seats, means for positively transmit ting the movement of said lever to the stem which actuates said pressure cracking valve, and delayed-acting means for thereafter transmitting the movement of said lever to the stem which actuates said main valve, the stem which actuates the pressure cracking valve being located closer to said pivot than the stem which actuates said main valve, whereby the greatest leverage is applied to the pressure cracking valve while maximum movement is transmitted to the main valve.

3. Mechanism for controlling the release of fluid under pressur including a main valve, a companion pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, means for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves off their respective seats, means for positively transmitting the entire movement of said lever to the stem which actuates said pressure cracking valve, and delayed-acting means for transmitting the entire movement of said lever to the stem which actuates said main valve, the stem which actuates said pressure cracking valve being located closer to said pivot than the stem which actuats said main valve, whereby the greatest lever age is applied to the pressure cracking valve while maximum movement is transmitted to the main valve.

4Q Mechanism for controlling the release of fluid under pressure including a main valve, a companion pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, means for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves off their respective seats, the initial part of the movement of said lever being positively transmitted to the stem which actuates said pressure cracking valve, and resilient means for transmitting the movement of said lever to the stem which actuates said main valve, said resilient means being compressed during the initial part of the movement of said lever and expanding after said pressure cracking valve has been opened to elevate the stem which actuates said main valve, the stem which actuates said pressure cracking valve being located closer to said pivot than the stem which actuates said main Valve, whereby the greatest leverage is applied to the pressure cracking valve while maximum movement is transmitted to the main valve.

5. Mechanism for controlling the release of fluid under pressure including a main valve, a companion pressure cracking valve, a control member for first opening said pressure cracking valve and thereafter opening said main valve, an element which is adjustable to advance and retard the action of the pressure cracking valve with respect to the main valve, and a second element which is adjustable simultaneously to advance and retard the action of both the pressure cracking and main valves with respect to said control member.

6. Mechanism for controlling the release of fluid under pressure including a main valve, a companion pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, means for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves off their respective seats, the initial part of the movement of said lever being positively transmitted to the stem which actuates said pressure cracking valve, a stop on said lever, and resilient means for normally holding the stem which actuates said main valve in spaced relation with respect to said stop, whereby during the initial part of the movement of said lever said pressure cracking valve will be opened'while 'said'resilint means will be compressed, said stop moving toward said last mentioned stem during such movement and being operative when-it reaches a predetermined point to positively actuate said stem and thereby unseat the main valve if it has not already been unseated by said spring, the stem which actuates said pressure cracking valve being located closer to said pivot than the stem which actuates said main valve, whereby the greatest leverage is applied to the pressure cracking valve while maximum movement is transmitted to the-main valve.

7. Mechanism for controlling the release of fluid under pressure including a main valve, a companion pressure cracking Valve, means for positively opening said pressure cracking valve, delayed-acting means for opening said main valve, a control member, an element which is adjustable to advance and retard the action of the pressure cracking valve with respect to the main valve, and a second element which is adjustable simultaneously to advance and retard the action of both the pressure cracking and main valves with respect to said control member.

8. Mechanism for controlling the release of fluid under pressure including a main valve,'a companion pressure cracking valve, stems for actuating said valves, a lever, a pivot to which said lever is connected, a control member for rocking said lever on said pivot about an axis normal to the plane of said stems to raise said valves off their respective seats, the initial part of the movement of said lever being positively transmitted to the stem which actuates said pressure cracking valve, resilient means for transmitting the movement of said lever to the stem which actuates said main valve, said resilient means being compressed during the initial part of the movement of said lever and expanding after the pressure cracking valve has been opened to open the main valve, the stem which actuates said pressure cracking valve being located closer to said pivot than the stem which actuates said main valve, whereby the greatest leverage is applied to the pressure cracking valve while maximum movement is transmitted to the main valve, means which is adjustable to advance and retard the action of the pressure cracking valve with respect to the main valve, and means which is adjustable simultaneously to advance and retard the action of both the main and pressure cracking valves with respect to said control member.

FRANK C. WILSON.

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