US2737928A - Hydraulic press - Google Patents

Description

March 13, 1956 D- B. NEFF ETAL HYDRAULIC PRESS 4 Sheets-Sheet 1 Filed Dec. 15. 1952 FIG. I

INVENTORS CECIL E-ADAMS y DRY ENEFF HYDRAULIC PRESS 4 Sheets-Sheet 2 Filed Dec. 15. 1952 mm 1 F a. 4 fl WWW A w M w Wm, 5 a \\\s LW 5 .w M H wymgsx, I A \+W- co a 3 2 a Y 5 M 5 7 M a 9/H/% 6 B H a M A d. R II m 0 T H" /Il/ 1. n m m w m 3 2 a 4 J 3 H e o o M 0 o W a H w w n w w o n 8 3 March 13, 1956 B. NEFF ETAL HYDRAULIC PRESS 4 Sheets-Sheet 5 Filed Dec. 15, 1952 FIG. 3

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BY on auzrr Jam/M1? W March 13, 1956 D. B. NEFF ETAL 2,737,928

HYDRAULIC PRESS Filed Dec. 15. 1952 4 Sheets-Sheet 4 FIG.

INVENTORS CECIL E. lDAMS 3y DARBY B.- NEFF MZM United States Patent HYDRAULIC PRESS Darby B. Nell and Cecil E. Adams, Columbus, Ohio, assignors to Denison Engineering Company, Columbus, Ohio This invention relates generally to hydraulic apparatus and is more particularly directed to hydraulic bench presses of the manually controlled type.

An object of this invention is to provide a bench press of small compact design having a novel control mechanism which will require the use of both hands of the operator during a portion of the cycle of operation to render the press safe for use and then, after the danger period is passed, the control becomes automatic in operation so that the cycle will be completed even though the operator may release the manual controlling elements.

Another object of the invention is to provide a bench press having a C-frame with base, back and head sections, the base section having a compartment to form a reservoir and receptacle for the major portion of the operating mechanism of the press, the construction providing a compact design in which the parts, normally subject to leakage of hydraulic fluid, are contained in the reservoir and any leakage will be confined therein thus causing no inconvenience.

Another object of the invention is to provide a hydraulic press having a power cylinder with a movable ram and a control mechanism for controlling fluid flow from the pump to the power cylinder, the press having manually actuated members for initiating the valve operation and additional mechanism responsive to predetermined movement of the ram to maintain valve and power cylinder operation whereby the cycle of operation will be automatically completed after having progressed to a predetermined stage. I

A further object of the invention is to provide a hydraulic press having a power cylinder with a movable ram and a control mechanism, including a valve with a spool and two control knobs which must be operated in unison to move the spool to a predetermined position to initiate forward operation of the ram, the control knobs being held in a certain position to keep the spool in its predetermined position until the ram has progressed far enough to actuate a means which causes the application of fluid pressure resulting from the forward operation of the ram to the valve spool to retain it in position to continue the forward operation of the ram; the use of two control knobs requiring the operator to employ both hands during the dangerous portion of movement of the ram after which the operators hands may be removed from the control without interrupting the cycle of ram operation. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a vertical sectional view taken through a hydraulic bench press formed in accordance with the present invention, the internal parts of the press being shown inside elevation;

Fig. 2 is an elevational view of the press taken from the back;

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Fig. 3 is a detail horizontal sectional view taken through line III-III of this figure and showing the control mechanism;

Fig. 4 is a vertical sectional view taken through the press on the plane indicated by the line lV--IV of Fig. 3;

Fig. 5 is a detail vertical sectional view taken through a portion of the control valve and operating mechanism therefor showing the valve in one position of operation;

Fig. 6 is a similar view showing the valve in another position of operation;

Fig. 7 is a detail vertical sectional view taken through the lower portion of a hydraulic power cylinder used in the press shown in Fig. 1 to show a check valve which serves as an unloading valve; and

Fig. 8 is a diagrammatic view of the hydraulic circuit employed in the press, parts of the hydraulic power cylinder and control valve mechanism therefor being shown in vertical section.

Referring more particularly to the drawings, the numeral 20 designates the hydraulic press forming the present invention. This press includes a modified C-shaped frame 21 which may be cast or otherwise formed from suitable metal. This frame includes a base section 22, a back section 23 and a head section 24, the latter projecting forwardly from the back section and overhanging the forwardly projecting portion of the base section. The head section has a bottom wall 25 which is formed with an opening 26 to receive suitable tooling, not shown, em

ployed when the press is in operation. The back sectionhas a forward wall 27 from the rear of which projects a lug 28, the purpose of which will be set forth hereinafter. Wall 27 also has a slot 39 extending upwardly in the central portion thereof, the purpose of this slot will also be set forth hereinafter.

The base section 22 includes the major portion of the operating mechanism of the press although, as illustrated in Fig. 2, the back section supports and substantially encloses the driving motor 31 which is secured to and supported by one of the side walls of the back section and the fluid pump 32 which is coupled, as at 33, to the driving shaft 34 of the motor 31, the pump 32 being supported by a bracket 35 also fixed to a side wall of the back section. The base section is formed with a compartment 36 which forms a reservoir to receive the hydraulic fluid employed to transmit the energy developed by the motor 31 to other mechanism which translates it into motion. This fluid is drawn from the reservoir by the pump 32 through a line 37 and forced through another line 33 to the control valve mechanism indicated generally by the numeral 39. The line 38 also communicates with a relief valve 40 which is diagrammatically shown in Fig. 8. This relief valve also communicates with an exhaust line 40A extending back into the reservoir 36. The relief valve may be located in any desired position. However, in one embodiment of the invention, it is also located in the reservoir 36 to prevent any possible leakage from being discharged exteriorly of the reservoir. The valve mechanism 39 controls the flow of fluid under pressure from the pump 32 to a power cylinder 41, lines 42 and 43 extending from the valve 39 to the upper and lower ends, respectively, of the cylinder 41. As shown in Fig. 1, the valve mechanism 39 and power cylinder 41 are also located within the reservoir 36 formed in the base section 22. The lines 42 and 43 are formed in the bodies of the valve and cylinder and thus reduce the amount of pipe or tubing used in the press.

Cylinder 41 receives a piston 44 for longitudinal movement, a ram 45 projecting from the piston through the upper end of the power cylinder into the space between the base and head sections to do useful work. As the piston 44 reciprocates in the power cylinder 41, the ram 45 will be projected into and retracted from the space between the base and head sections of the frame 21. Any suitable tools may be secured to the upper end of the ram 45 when the press is to be operated. The direction and rate of movement of the piston 44 in the power cylinder is controlled by the position of a valve spool 46 in the casing 47 of the control valve mechanism 39.

Control valve mechanism 39 is of the generally designated four-way type, the casing including a bore 48 for receiving the spool 46, a port 50 with which the line 38 leading from the pump 32 communicates, and upper and lower work or cylinder ports 51 and 52, respectively. Port 51 communicates with line 42 leading to the upper end of the power cylinder 41 while port 52 communicates with line 43 leading to the lower end thereof. Spool 46 is formed with an external groove 53 which serves in various positions of the spool to establish communication between the inlet port 50 and either of the work ports 51 and 52. Spool 46 is also formed with a plurality of internal recesses or passages which connect either port 51 or 52 with exhaust when the other port is connected with the inlet port. Spool 46 is normally biased in an upward direction by a coil spring 54 disposed between the inner end of the recess at the lower end of a spool and a plate 55 secured to the bottom of the casing 47 This plate has an opening 56 through which fluid may flow from the casing to the reservoir. The upper end of the casing 47 has a top section 57 secured thereto, this section having a passage 58 formed therein which establishes communication between the upper end of the bore 48 and a downwardly directed tube 59 secured to the cover 56. Tube 59 terminates in spaced relation from the bottom wall of the reservoir 36.

It will be obvious from the drawing and the description thus far given that fluid may flow from either end of the bore 48 into the reservoir. The valve spool 46 .is shown in the position occupied when the press is idle in Figs. 4 and 8. In this position, the groove 53 establishes communication between the inlet groove 50 and the lower or bottom work groove 52. Fluid under pressure from the pump 32 is thus directed from the groove 50 to the groove 52. This fluid has access to the lower end of the power cylinder through conduit 43 but, inasmuch as the spool 46 is blocking the top cylinder groove 51 to prevent exhaust from the upper end of the cylinder and has lateral passages 69 establishing communication between the groove 52 and the interior of the spool 46, fluid may flow through the passages 60 and the interior of the spool to the lower end of the bore 48 from which it may flow from port 56 to the interior of the reservoir. Since the fluid follows the line of least resistance, it will flow into the reservoir rather than into the lower end of the power cylinder.

To actuate the spool 46, the press is provided with a pair of control knobs 61 shown more particularly in Fig. 3. These control knobs project from the forward wall of the base section, being carried by rods 62 which extend through openings in the forward wall of the base and loosely connected at their inner ends with a transversely extending equalizer bar 63. This bar is pivotally secured at its central point to a link 63A which is, in turn, secured to a bell crank 64 pivoted, as at 65', to the top section 57 of the control valve mechanism 40. Crank 64 has a rearwardly extending branch 66 which is provided with an adjustable screw 67. This screw is disposed in vertical registration with the end of a pushrod 68 pro jccting from the spool 46 through an opening in the top section 57. The pushrod is normally maintained in engagement with the end of screw 67 due to the force exerted on the spool by the spring 54. The expansion of the spring 54 moves the spool 46 in an upward direction transmitting this movement to the 'pushrod 68 which, in turn, transmits such movement to the bell crank 64 causing movement thereof about the pivot 65. This movement is transmitted to the control rods 62 forcing these members forwardly through the openings in the front wall of tion is limited by collars 70 secured to the rods 62. Movement of the spool 46 is also limited by engagement of the upper end thereof with the end of a projection 71 formed on the cover section 57 and extending into the upper end of the bore 48. The valve spool is shown in this position in Fig. 5. When the valve spool occupies this position, the inlet port 50 is connected by the groove 53 with the top cylinder port 51 and fluid from the pressure source will then be directed through the line 42 to the upper end of power cylinder 41.

This fluid will be applied to the upper surface of the piston 44 and will tend to move it, together with the ram 45, in a downward direction. When the piston 44 moves in a downward direction, fluid will be discharged from the lower end of the power cylinder through line 43 to groove 52 and will flow through the lateral ports 60 and additional lateral ports 72 to the interior of the spool from which it will flow to the lower end of the bore 48 and through port 56 to the interior of the reservoir. Immediately prior to engaging the bottom wall of the power cylinder, piston 44 will, as shown in Fig. 7, expose a p011 73 extending laterally from the power cylinder. This port communicates with a chamber 74 which, in turn, communicates with another port 75 leading from the passage 43. Chamber 74 receives a check valve 76 and a spring 77 which normally urges the check valve into position to close the port 73. When the upper end of the power cylinder is connected with the pressure source and the piston 44 occupies its lowermost position, fluid supplied to the upper end of the power cylinder may be discharged through the passages 73, 74, and 75 to the passage 43 from which it may flow directly into the reservoir 36. The pump or other pressure generating means will then be unloaded even though the valve spool 46 is in position to cause the retraction of the piston 44 and ram 45.

The control mechanism also includes a rod 78 termed, in the trade, a shipper rod. This rod is guided in an opening formed in the lug 28 and another opening formed in the top '57 of the casing 47. This rod extends downwardly through the tube 59 which projects from the top member 57. The rod 78 is provided with a collar '80 for engagement with the top member 57 to limit the downward movement of the rod. It is also provided with an adjustable, resilient, lost-motion mechanism designated generally by the numeral 81. This mechanism includes a collar 82 which is adjustably secured to the rod 78 and a collar 83 disposed for sliding movement on the rod 78. The latter collar is connected with collar 82 by a frame 84 to permit the collar 83 to move toward the collar 82 and limit the movement in the opposite direction. Between the collars 82 and 83, there is provided a coil spring 85. This lost motion connection permits the transmission of motion from the ram 45 to the rod 78 through an arm 86, secured to the ram 45 and projecting rearwardly through the opening 30 to and surrounding the rod 78. When the ram moves in an upward direction, the arm 86 will move likewise. It will engage the collar 83 causing it to move in an upward direction also. This upward movement is transmitted through the spring 85 and collar 82 to the rod 78 causing this rod to move upwardly until a resilient disk valve 87 engages the lower end of the downwardly projecting tube 59. After the disk 87 engages the tube, further movement of the arm 86 merely serves to compress the spring 85. The valve 87 is supported on the rod 78 by a collar 88. When the valve engages the tube 59, free flow of exhaust fluid through this tube is resisted to create a back pressure. Some exhaust flow, however, is permitted through a port 90 formed in the tube adjacent its lower end.

In the operation of the press, the operator engages both control knobs 61 and moves them inwardly. This motion is transmitted through the rods 62, bar 63, link 63A, and bell crank 64 to the pushrod 68 moving this red and the spool 46 in a downward direction to the position shown in Fig. 6. In this position, spool 46 establishes communi cation between the inlet port 50 and the bottom cylinder port 52. Fluid may then flow from the pressure'source through the line 43 to the lower end of the power cylinder 41. This fluid is applied to the bottom of the piston 44 causing this piston and the ram 45 to move in an upward direction. Fluid in the power cylinder 41 above the piston will be exhausted through line 42 to groove 51 from which it will flow through lateral ports 91 formed in spool 46 to the interior of the spool and then to the upper end of. the bore 48 from which it will flow through passage 58 and tube 59 to the interior of thereservoir.

If the operator should release either knob 61 during the upward movement of the ram 45 before the arm 86 engages the collar 83, the spring 54 will move the spool 46 upwardly to the position shown in Figs. 4 and 8. In this position, communication between the top cylinder groove or port 51 and the ports 91 in spool 46 will be interrupted and the upward movement of the ram 45 will be precluded. If both knobs are released, the spool will be moved to the position shown in Fig. 5 in which the top cylinder port 51 will be connected with the source of fluid pressure and fluid will flow to the upper end of the power cylinder to cause the retraction of the ram 45; When the control knobs 61 are held in their innermost positions until the ram 45 moves in an upward direction a sufiflcient distance to cause the arm '86 to engage the collar 83 and move the rod 78 in an upward direction causing valve 87 to close the lower end of tube 59, a back pressure will be created on the fluid flowing from the upper end of the power cylinder. This back pressure will be applied to the upper end of the valve spool 46 and will hold this spool in its lowermost position shown in Fig. 6.

At this time, knobs 61 may be released without interrupting the operation of the power cylinder. Since the lost motion mechanism 81 is adjustable on the rod 78, the point at which automatic operation will commence may be varied depending upon the desires of the manufacturer and user and the tooling with which the press is equipped. It is desirable to delay the automatic operation until the relatively movable die elements or other tooling members have approached one another sufliciently to prevent the operator from inserting his hands or other body members therebetween. This feature constitutes a safety measure and renders the device as foolproof as possible.

When the ram has reached the end of its movement in an upward direction which will be determined by the tooling disposed in the press or the engagement of the piston 44 with the upper end of the power cylinder, the ram will stop moving. When this interruption to movement occurs, the flow of exhaust fluid from the upper end of the power cylinder will cease and the back pressure will be dissipated through the port 90. The spring 54 may then move the valve spool 46 to its uppermost position, assuming the control knobs 61 have been released, to connect the fluid pressure source with the upper end of the power cylinder and effect the retraction of the ram. The force exerted by the ram will be determined through the adjustment of the relief valve 40 in the usual manner. t

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

We claim:

1. Hydraulic apparatus comprising a source of fluid pressure; a reversible fluid motor having a movable element; control mechanism between said pressure source and said motor, said control mechanism having a reversing valve movable between two extreme positions in which said motor is connected with said pressure source and caused to operate in forward and reverse directions; selectively operated means for moving said reversing valve to one extreme position to cause forward operation of said motor; resilient means tending to urge said reversing valve to the other extreme position to cause said motor to operate in the opposite direction; means responsive to continuous forward movement of the movable element of said fluid motor for applying fluid pressure to said reversing valve to prevent movement thereof by said resilient means; and motion transmitting means actuated by the movable element ofsaid motor at a selected stage of forward operation for rendering said fluid pressure applying means operative.

2. Hydraulic apparatus comprising a source of fluid pressure; a reversible fluid motor having a movable element; control mechanism between said pressure source and said motor, said control mechanism having a reversing valve movable between two extreme positions in which.

said motor is connected with said pressure source and caused to operate in forward and reverse directions; manually operated means for moving said reversing valve to one extreme position to cause forward operation of said motor; resilient means tending to urge said reversing valve to the other extreme position to cause said motor to operate in the opposite direction; means responsive to continuous forward movement of the movable element of said fluid motor for applying fluid pressure to said reversing valve to prevent movement thereof by said resilient means; and motion transmitting means actuated by the movable element of said motor at a selected stage of forward operation for rendering said fluid pressure applying means operative.

3. Hydraulic apparatus comprising a source of fluid pressure; a reversible fluid motor having a movable element; control mechanism between said pressure source and said motor, said control mechanism having a reversing valve movable between two extreme positions in which said motor is connected with said pressure source and caused to operate in forward and reverse directions; valve operating means having a pair of actuating elements and motion transmitting means extending between said elements and said reversing valve, movement of both elements to certain positions being necessary to place said reversing valve in one extreme position to cause forward motor operation; resilient means tending to urge said reversing valve to the other extreme position to cause said motor to operate in the opposite direction; means responsive to continuous forward movement of the movable element of said fluid motor for applying fluid pressure to said reversing valve to prevent movement thereof by said resilient means; and motion transmitting means actuated by the movable element of said motor at a selected stage of forward operation for rendering said fluid pressure applying means operative.

4. Hydraulic apparatus comprising a source of fluid pressure; a reversible fluid motor having a movable element; control mechanism between said pressure source and said motor, said control mechanism having a reversing valve movable between two extreme positions in Which said motor is connected with said pressure source and caused to operate in forward and reverse directions; valve operating means having a pivoted lever; a link pivotally connected intermediate of its ends to said lever; a pushrod connected for universal movement to each end of said link; resilient means tending to urge said reversing valve to the other extreme position to cause said motor to operate in the opposite direction; means operative during continuous forward movement of the movable element of said fluid motor for applying fluid pressure to said reversing valve to prevent movement thereof by said resilient means; and motion transmitting means actuated by the movable element of said motor at a selected stage of forward operation for rendering said fluid pressure applying means operative.

5. A hydraulic press comprising a source of fluid pressure; a cylinder having a reciprocable ram; control mechanism for'said ram between said pressure source and said cylinder, said control mechanism having valve means with a casing communicating with the pressure source, opposite ends of said cylinder and exhaust; a valve spool in said casing, said spool being movable between a first position to connect one end of said cylinder with said pressure source and the other end to exhaust to cause forward operation of said ram and a second position to reverse such connections to cause reverse operation of said ram; manually operated means for moving said spool to the first position; resilient means tending to shift said spool from said first to said second position; fiow resisting means rendered operative by said ram at a selected stage of movement in the forward direction to resist the exhaust flow from said cylinder to create a back pressure; and passage means for applying such back pressure to said spool to resist movement thereof from said first position by said resilient means.

6. In a hydraulic press, a reciprocable ram; control mechanism for said ram having a reversing valve; actuating means for said reversing valve, said means being operative to dispose said valve in a position to cause said ram to move in one direction, spring means tending to move said reversing valve to a second position to cause said ram to move in the opposite direction; means for resisting the movement of said valve to said second position by said spring means, said resisting means having means responsive to continuous movement of said ram in said one direction to maintain a hydraulic pressure; and means for applying such pressure to said valve.

7. In a hydraulic press, a reciprocable ram; control mechanism for said ram having a reversing valve; actuating means for said reversing valve, said means being operative to dispose said valve in a position to cause said ram to move in one direction, spring means tending to move said reversing valve to a second position to cause said ram to move in the opposite direction; means for resisting the movement of said valve to said second position by said spring means, said resisting means 'having means responsive to continuous movement of said ram in said one direction to maintain a hydraulic pressure; means for applying such pressure to said valve; and a bleed passage for dissipating said hydraulic pressure when movement of said ram in said one direction is discontinued to permit movement of said valve by said spring means.

8. In a hydraulic press, a reciprocable ram; control mechanism for said ram having a reversing valve; actuating means for said reversing valve, said means being operative to dispose said valve in a position to cause said ram to move in one direction, spring means tending to move said reversing valve to a second position to cause said ram to move in the opposite direction; passage means for fluid displaced by movement of said ram in said one direction; means for opposing fluid fiow from said passage to create a back pressure, said valve being exposed to such back pressure to oppose movement of said valve by said spring means; and motion transmitting means actuated by said ram at a predetermined stage of movement to render said fluid flow opposing means operative.

9. In a hydraulic press, a reciprocable ram; control mechanism for said ram having a reversing valve; actuating means for said reversing valve, said means being operative to dispose said valve in a position to cause said ram to move in one direction; means automatically tending to move said reversing valve to a second position to cause said ram to move in the opposite direction; passage means for fluid displaced by movement of said ram in said one direction; means for opposing fluid flow from said passage means to create a back pressure in said passage means, said valve being exposed to such back pressure to resist movement by said automatic means while said ram ,is moving in said one direction; motion transmitting means actuated by said ram at a predetermined stage of movement thereof to render said fiow opposing means operative; and bleed passage means for dissipating the back pressure when movement of said ram in said direction is discontinued to permit said valve to move to said second position and cause movement of said ram in the opposite direction.

R ferences {Iiteei in the file of this patent UNITED STATES PATENTS 1,676,866 Maury July 10, 1928 1,829,184 Daly Oct. 27, 1931 2,169,470 Miller Aug. 15, 1939 2,473,167 Mills June 14, 1949 2,512,731 Adams June 27, 1950 FOREIGN PATENTS 403,154 Great Britain Dec. 27, 1933

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