US2188956A - Hydraulic press - Google Patents

Description

F051). 6, 1940- A. A. QNORIN ET AL HYDRAULIC PRESS 4 6 Sheets-Sheet 1 Filed 001:. 10, 1935 Feb. 6, 1940. NORIN ET AL 2,188,956 I HYDRAULIC PRESS I Filed Oct. 10; 1955 6 Sheets-Sheet 2 lllliiiillliiiliiiiiillfl'm FebQG, 1940. A. A. NOIRIN ET AL. I I 8 HYDRAULIC PRES S Filed Oct. 10,1935 6 Sheets-Sheet s m N :1 Lil -'-o\ R W 4 b Feb. 6, I A.'A. NORIN ET AL HYDRAULIC PRESS Filed Oct. '10. 1955 e sheets-sheet 4 Feb. 6, 1940. A. A. NORIN ET AL HYDRAULIC PRESS Fi led Oct. 10, 1935 e Sheets-Sheet 5 a It;

Feb. '6, 1940.

A. A. NORIN ET AL HYDRAULIC' PRESS Filed Oct. 10, 1935 6 Sheets-Sheet 6 Patented Feb. 6, 1940 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to hydraulic presses and more particularly to a hydraulic device adaptable for use as a press or in connection with similar tools wherein a maximum number of applications of energy to a concentrated work point is desired, and especially where it is desirable that the application of a predetermined maximum amount of energy should be applied substantially instantaneously.

It is common practice, in connection with hydraulic pumps, to use a power source, such as an electric motor, of a power rating sufficiently high to store and maintain a constant pressure from which energy may be drawn at any time l6 and transferred to the point of application. Such pumps consume a very great amount of energy in maintaining the pressure and require large and expensive motors and complicated mechanisms in which a great amount of energy is lost in the transferfrom the point of generation to the point of useful work. Maintaining ahigh pressure at some point within such pumps necessitates the dissipation of a great amount of energy other than that required to do the work.

It is an object of the present invention to pro-' vide a hydraulic press using a power source of minimum size and power rating and in which the energy is directed from a suitable energy conserving device, preferably a flywheel, directly to the point of application, and in which all of the energy used is expended in useful work at the moment of application.

The present invention maintains a source of maximum potential energy and transfers a desired amount of this potential energy to the point of application without appreciable loss of energy during its transmission. In other words, the invention uses a minimum amount of power to maintain a potential energy at a maximum and this maximum amount of energy is available for useful Work at a desired point of application with a minimum loss of energy during the transfer from the source to the point of application.

A further object is to provide a hydraulic device of the character described having a completely closed hydraulic circulating system, so far as the flo'w of fluid is concerned, in which there is substantially no loss of fluid and all the parts are self-lubricating by means of the fluid used within the pumping system.

Another object is to provide a novel reversing arrangement which is entirely automatic and controlled solely by fluid pressure at the time of application of such pressure to the work; that is, the reverse operation is preferably accomplished by the predetermined maximum useful pressure applied to the work.

A further object is to provide a hydraulic press 5 of minimum size and maximum energy producing capacity which will be of few parts, without gears, or mechanically operated trips, valves, or detents, and in which all separate pipes or con- .duits are eliminated; also, which may be manu- 10 factured at a minimum cost and. be easily and quickly assembled.

The invention' also contemplates a momentum controlled fluid pressure unit of very small size relative to the pressure developed and which may 15 be easily and cheaply installed in connection with existing presses without materially increasing the overall dimensions of the original installation. In fact, in many instances the dimensions may be materially reduced. Also the installation of the unit may be accomplished very quickly and at a minimum cost.

Further objects will 'be apparent from the specification and the appended claims.

In the drawings:

Figure 1 is a perspective view of one embodiment of the invention incorporated in a portable device having a piston operated pressing tool associated therewith.

Fig. 2 is a somewhat diagrammatic view illustrating the use of a plurality of pistons with a single controlling valve.

Fig. 3 is a vertical section through the pressure developing unit and taken on a line substantially corresponding to line 33 of Fig. 4.

Fig. 4 is a left hand end view of the embodiment illustrated in Fig. 3.

Fig. 5 is a transverse sectional view through the lower base of the machine and'the control valve therein and taken on a line substantially corresponding to line 55 of Fig. 3.

Fig. 6 is a longitudinal sectional view through a controlling valve somewhat similar to that illustrated in Fig. 5, but arranged to provide for automatic fluid-controlled return stroke of the 45 work piston. The conduits or channels in this embodiment are illustrated diagrammatically.

Fig. 7 is a somewhat diagrammatic side elevation illustrating one application of the pressure unit to an ordinary press.

Fig. 8 is a front view of the embodiment illustrated in Fig. '7.

Fig. 9 is a vertical section through the reciprocating pump valve and thechannels or conduits leading to the reservoir and is taken on a line 55 substantially corresponding to line 99 of Fig. 3.

Fig. 10 is a diagrammatic view illustrating the position of the controlling valve and associated elements after the valve has been manually or otherwise moved to fluid blocking position to cause a working operation of the device.

'Fig. 11 is a diagrammatic view similar to Fig.

10 but with the controlling valve moved by bypassed fluid pressure to pressure relieving position, and with the associated elements moved to a position whereby energy is stored to continue the movement of the valve to the normal position shown in Fig. 5 after pressure to the by-pass is closed. Fig. 12 is a transverse sectional view through the controlling valve and illustrates the return conduit to the reservoir and is taken on a line substantially corresponding to line l2-I2 of Fig. 5.

Fig. 13 is a detail section taken on a line substantially corresponding td' line l3|3 of Fig. 5.

Fig. 14 is a fragmentaryelevation of an indicating dial arrangement .for determining the operating pressure. rd

Referring to the drawings in detail, the em- 5,-

3 end to provide a channel 39 communicating with the oil chamber 6 and the piston passage 23 through a series of perforations 3| in the sleeve bodiment illustrated, comprises a pump unit I which encloses substantially all of the operating V parts and which, due to the small number of parts used, may be of a minimum size to provide a maximum amount of available energy. The unit I comprises an integral lower base 2 for supporting the pistons, and an upper base 3 having inturned flanges 4: by which it may be secured to the base 2 by means of suitable bolts or machine screws 5. The upper base 3 provides 1 a reservoir 5 for containing a supply of a suitable fluid, such as oil, and is provided with a cover 1 having vent openings 8 therein and a bafile plate 9 arranged to prevent the fluid from being thrown through the vents. It will be apparent that the lower and upper bases 21-and 3 may be a single integral casting if desired.

A crank shaft I0 is mounted in suitable antifriction bearings II in the upper base 3, and a flywheel or so-called balance wheel l2 of appropriate size, in accordance with the energy to be developed by the machine, is secured to the crank shaft it) outside the casing-as illustrated. A comparatively small electric motor or other power source i3 is preferably directly connected to the crank shaft III as illustrated in Fig. 1. It will of course be apparent that any suitable transmission, such as a belt, may be used from. the motor l3 to the crank shaft II] in accordance with the speed required of the pump.

'ton I6 is somewhat shorter than the piston 05 and is operatively connected to an eccentric E8 on the crank shaft ID by means of a connecting rod i 9. In a similar manner the piston I5 is connected to an eccentric 20 on the crank shaft ill by means of a connecting rod 2|. The eccentrics l8 and 20 are degrees ofiset on the crank shaft as illustrated in Fig. 4, whereby when one piston is being raised, the other piston is moving downwardly- Y A valve sleeve 22 is inserted in the base '2 between the pistons and i5 and preferably in the same vertical plane and is provided with a reciprocating valve 23 operatively connected to an eccentric 26 on the crank shaft to by means of a connecting rod 25. The valve eccentric 24 is preferably positioned at ninety degrees relative to the piston eccentrics l3 and 20 as illustrated in Fig. 4. It will therefore be apparent that when the pistons are at the extreme limits of their stroke and their eccentrics are positioned as in Fig. '4, and moving in the direction of the arrow, the valve 23 will be in its mid-stroke position and traveling at its highest speed, and, vice versa, when the pistons are in mid-strokeand traveling at their highest speed, the valve 23 will be at or adjacent its stroke limit and traveling at its slowest speed. This relationship is important for the proper co-operation of the valve and. pistons in order to prevent pressures developing in the system which might cause a dissipation of energy which could otherwise be made available for useful work.

The valve 23 is provided with reduced portions forming passages 26 and 21 between the valve and the sleeve 22. The valve is also provided with spaced comparatively wide split rings 28 and 29. These rings are hardened and ground step-split rings, the'step split preventing leakage of oil from eitherside to the other. The sleeve 22 is reduced in diameter at its upper cylinders of the'pistons l4 and I5, the pistons will alternately pump this oil into the interior of the sleeve 22 if the valve 23, is positioned to permit the oil to pass through the respective openings in the sleeve.

Another series'of perforations 36 is provided in the sleeve 22 and positioned intermediate the openings 33 and 35. These openings 33 communicate with a so-called work pressure passage 31 in the base to which may be connected a suitable cylinder 38 having a work applying piston 39 therein normally held in the position illustrated by means of a light spring 40. This spring is only sufliciently strong to return the piston to normal position after it has been applied to the work.

The operation of the above described portion of the device is as follows: i

The piston 54 has just completed its downward stroke (Fig. 3) and during this downward stroke, the valve 23 has been making the upper half of its upward stroke and the upper half of its downward stroke. Therefore the valve ring 28 has been above the openings 33 at all times d'uringfii downward stroke of the piston l4, and the valve ring 29 has necessarily been moved upwardly and downwardly in a corresponding manner from and to the position shown in Fig. 3 and relative to the openings 35. It is therefore apparent that during the downward stroke of the piston M, the fluid will be forced from the cylinder of the piston M through the conduit 32, the series of openings 33, the valve passage 21, and through the series of openings 36 into the work pressure channel 31.

- During the time that the piston I4 is substan tially stopped in its lowermost position, the valve speed. The ring 28 therefore quickly passes the openings 33 leading to the piston, at a time when the piston is not moved sufliciently to cause any material pressure or vacuum in the channel 32 and thereby dissipate energy. As soon as the valve 23 has moveddownwardly sufliciently to permit the ring 28 to pass the openings 33, the piston 14 increases its upward speed due to the relative position of the eccentric on the crank shaft, and oil is then drawn from the reservoir 6 through the sleeve channels 36, the openings 3|, the valve passage 26, the'openings 33 and the channel 32 leading to the cylinder of the piston. The work-pressure channel 31 into which the oil is pumped by the downward movement of the piston I4 is normally open to the reservoir 6 through a suitable channelv and therefore there will be no appreciable pressure developed in the system due to the fact that the oil freely circulates from the reservoir 6 through the cylinder of the piston l4 and into the channel 31 from which it freely returns to the reservoir 6. Means is provided whereby the passage from the work pressure channel 31 to the reservoir may be temporarily closed when desired to apply energy for the operation of the work piston. This mechanism will be described in detail later.

The piston l5 and the fluid controlled thereby operates in exactly the same manner; that is, during the upward stroke of the piston l5, the valve ring 29 is positioned above the series of openings 35 in the valve sleeve 22 and the piston therefore draws fluid from the reservoir 6 through a conduit 4| which communicates with the open bottom end of the valve sleeve 22, and, through the series of openings 35, also communicates with a channel 34 leading to the lower end of the cylinder of the piston l5. While the piston I5 is at 'the upward limit of its stroke,

the valve 23 moves downwardly to position the the downward stroke of the piston I 5, the fluid in the conduit 34 flows through the openings 35, the valve passage 21, and through the sleeve openings 36 into the work-pressure passage 31 and from there returns to the reservoir 6 through the return passage previously mentioned. It will therefore be apparent that, when the return passage from the channel 31 to the reservoir 6 is closed, all down strokes of the pistons will create a pressure in the work passage 31 and against the working piston 39 to move the piston against the work. As soon as this pressure is released by opening, the return passage, a light spring 46 will return the pistonto the normal I position illustrated.

In order to permit free flow of fluid from and to the reservoir 6 and to provide free and unrestricted movement of the valve 23 the valve is provided with an internal'bore as indicated by the dotted lines 41a in Fig. 3 and in full lines in i Fig. 9. The open lower end of this bore com- In order to close the return passage from the channel 31 to the reservoir 6 and apply pressure 'to the piston 39 and to reopen the passage as soon as the work has been accomplished, a control mechanism is provided which is illustrated in detail in Fig. 5. This control mechanism comprises a horizontally positioned valve member 42 which is slidably mounted in a sleeve 43 inserted in the base asillustrated This valve is provided with a restricted portion 44 providing a fluid passage 45 within the sleeve. The valve is also provided with a special wide step-split ring 46 and step-split piston rings 41. The workpressure channel 31 communicates with the valve passage 45 through a series of openings 48 in the valve sleeve 43, and the valve passage 45 communicates through a similar series of openings 49 in the valve sleeve, with a vertical conduit 50 indicated by the dotted circle in Fig. 5 and leading directly to the. reservoir 6. It will therefore be clear that with the valve 42 in the position illustrated in Fig. 5 any fluid pumped into the passage 31 will freely pass through the sleeve openings 48, the valve passage 45,the sleeve openings 49 and through the conduit 56 into the reservoir from which it is returned to the pistons in the manner previously described. Therefore, with the valve in this normal position as illustrated, there will be a free circulation of fluid and no material pressure will be developed. It will also be apparent that if the valve 42 is moved to the right as shown in Fig. 10 so that the. ring 46 passes the openings 48, the passage to the reservoir will be closed and pressure will immediately develop in the channel 31 tooper ate the piston 39, and as soon as the valve is moved to the left again to uncover the openings 48, a further unrestricted circulation of the fluid will againtake place and the piston 39 will be returned to its normal position by the spring 40.

The valve 42 is provided. with a longitudinal bore 5| therethrough, the bore being enlarged adjacent the right hand end to provide a valve seat 53. The right hand end of the valve bore 5| is closed by means of a plug 54 threaded therein and provided with openings 55 for the circulation of fluid therethrough. A so-called poppet valve 56 is seated against the valve seat 53 by means of a spring 51 hearing against the plug 54. The poppet valve 56 is provided with a valve stem 58 extending through the control valve and extending from the base andprovided with a suitable packing box 59 through which the valve stem may be moved. A piston 66 is positioned adjacent the right hand end of the valve sleeve 43 and normally held against the end of the valve sleeve 43 by means of a spring 6| bearing against a suitable plug or cap 62 having an inwardly extending portion 62efor the purpose of limiting the outward stroke of the piston.

The piston 66 is provided with a restricted portion 63 forming a passage communicating with the bore of the valve sleeve 43 through auxiliary passages 43a. A channel. 64 communicates with the bore of the valve sleeve through the passage formed by the restricted portion 63 of the piston andthe passages 43a. This channel 64 also communicates with the pressure conduit 31 through normally closed passages 65 and 66. These passages 65 and 66 are normally closed by means of needle valves 61 and 68, respectively. The valves 61 and 68 are yieldably retained in closed position by means of springs 69 and m. The tension of the spring 69 controlling the valve 61 may be manually adjusted by means of ill a thumb screw 1| bearing against the spring 69.

of a lock nut 12. The valve 61 may be adjusted to open at the maximum working pressure in the pressure in the passage 31, and the valve 68 is adjusted to function at a somewhat higher pressure and provide a safety valve in case the valve 61 should stick or fail to operate properly.

The operation of the device, is substantially as follows:

With the machine running at comparatively high speed and the parts in the position described, th'e fluid will be freely circulating from the reservoir through the conduits and back to the reservoir. However, if the valve stem 58 is pushed inwardly either manually or otherwise, the poppet valve 56 will open slightly against the pressureof the spring 51, thereby permitting the fluid in the right hand end of the sleeve and adjacent the piston 60 to pass freely through the openings 55 inplug 54 and through the valve the valve to be freely moved to the right by any suitable means such as a solenoid 14 or a manually or mechanically operated lever.

As the valve moves to the right, the series of valve sleeve openings 48 communicating with the pressure channel 31 will be closed by the split ring 46 and as soon as this takes place, pressure develops in the passage 31 to move the working piston 39 to apply pressure to the work. As soon as the pressure is increased to a predetermined value, to which the needle valve 61 is adjusted, the valve 61 will open and some pressure will be applied through the passage 64 between the valve piston 60 and the valve 42. The high pressure also tends to expand the wide split ring 46, as well as the other piston rings 41, and

these rings therefore develop considerable fric-.

tion against the walls of the sleeve 43 to prevent movement of the valve. These rings are comparatively wide and are normally of larger dimension than the piston chamber.

fore arranged to provide less resistance than the" friction of the valve ,42, and the fluid back of the piston is freely vented to the chamber by a suitable conduit indicated by the dotted circle- Bl' in Fig. 5 and in full lines in Fig. 131 The pressure against the piston 60 will therefore first compress the spring GI and the piston will move to the right against the stop He. As soon as the piston strikes the stop 52, the pressure of the fluid from the passage 64 will overcome the resistance of the split rings of the valve and the valve will move to the left until the sleeve openings 48 leading from the passage 31 are open slightly. At this point the valve 42 would stop and would not completely uncover the openings 48 as the pressure of the fluid is immediately relieved. However, as soon as this pressure is relieved, the piston 60 is returned to its normal position by means of the spring 6| thereby mov- Thereforetheir natural tendency to expand forces them.

ing the piston 60 to the left. I'he pressure of the piston on the fluid intervening between the piston and the valve forces the valve completely to the left to the normal position illustrated and thereby quickly and completely opens the sleeve passages 48, thereby preventing any restriction in the free flow of the fluid through the entire system. This entire operation is substantially instantaneous and the valve does not hesitate at an intermediate position.

In order to, provide for remote control of the device and instantaneous application of pressure at any desired moment, a solenoid 14 or any other suitable electrical device may be provided to operate the valve stem 58, whereby the valve may be moved inwardlyto close the return passagev to the reservoir. This arrangement is illustrated Fig. 1 in which the solenoid may be mounted in a suitable casing 15 and connectedto a suitable controlling device such as a trigger or lever 16 which may be arranged to control an electrical switch or other suitable mechanism.

In Fig. 1 the trigger it is mounted on a pres-' I sure applying tool 11 in which a punch 18 is connected to the piston 39 mounted in the cylinder 38, the cylinder 38, being connected to the pressure passage 31 by means of a conduit 18.

A number of pistons may be mounted in line on a single crank shaft as illustrated in Fig. 3,

the crank shaft being suitably extended for the purpose, or, the pistons and reciprocating valves may be arranged in a ninety degree V-shaped assembly, such as illustrated diagrammatically in Fig. 2 and the controhvalve may be placed in the angle as shown.

Regardless of the number of pistons or the number of reciprocating valves associated therewith, the application of pressure may be effectively controlled by means of a single control valve, such as illustrated in Fig. 5.

It is sometimes desirable to return the powerapplying piston 39 by fluid pressure instead of by means of the spring 40. In such cases, the

work piston performs a complete cycle by fluid pressure, that is, a working movement and return with eachcontrol movement of the valve 42. In order to accomplish this, the control valve is slightly modified as illustrated in Fig. 6'.

The embodiment illustratedin Fig. 6 comprises a valve sleeve having a valve 8| slidably' mounted therein. The valve 8| is somewhat similar to the valve 42 illustrated in Fig; 5 and is provided with a special type of wide split rings 82 and '83, as well as an ordinary split ring 84 adjacent the end of the valve. The valve is provided with two restricted portions forming passages 85 and 85, respectively. The internal construction of the valve is substantially identi cal with the valve 42 and is provided with an internal longitudinal bore 5la, a valve seat 53, a

poppet valve 56a normally seated by means of a spring 51a and retained by means of a perfo-r rated plug 5 5a having openings 55a therethrough. The valve 56a is provided with a valve stem 58:: which may be controlled manually or by a suitable solenoid as previously described. A piston 59a extends through this supplementary valve and the valve may be pushed inwardly with the main control valve-8| to the position illustrated, by means of a collar 90 secured to the valve stem. The main control valve 8| is shown in this embodiment at the extreme right hand end of the through a series of openings 95.

sleeve and when it returns to the extreme left hand limit of its movement, the reduced end 9| openings 93 in the valve sleeve. The other end of the cylinder 38a is connected to the interior of the sleeve 80 by means of a conduit 94 communicating with the. interior of the sleeve The pressure passage 31 is provided with a conduit 96 communicating 'with the interior of. the sleeve through a series of openings 91 at the left hand end of the sleeve. The pressure passage 31 also communicates with the interior of the sleeve adjacent its center by means of a conduit 98 communicating with the interior of the sleeve through a series of openings 99-. 'Another series of openings Hill is provided through the sleeve 80 and a passage communicates with the space at the left hand side of the auxiliary valve 81 so as to permit free flow of oil from the back of the auxiliary valve to the reservoir 6 through a conduit lfllia, when the valve-is moved. Another series of openings I02 are provided adjacent the other end of the sleeve 99 and communicating with the valve passage 86 and a conduit 86a leading to the reservoir 6 to permit free flow of oil to and from the valve. I

The operation of the device .is substantially as follows:

With the valve 8| in the position illustrated, the mechanism is in position to provide a forward stroke of the work piston 39a and the pressure will immediately be applied from the pressure passage 31 through the conduit 98, sleeve openings 99, valve passage 85, sleeve openings 99, and through the conduit 92 to the right hand end of the work cylinder 38a to move the piston 39a against the work. During this movement of the piston 38a the oil from the left hand end of the work cylinder freely moves throughthe conduit 94 and sleeve openings 95 and'backto; the reser voir through the return condit IOOa Q-As soon as the work is contacted and the prissure in-'-' creases to a predetermined amount ontrolled by the adjustable valve 61, this valve '61 raises .slightly and permits pressure to be applied through the conduit 64a to the right hand end of the valve 8|. The friction of the valve 9| due to the pressure on the rings prevents its being moved and the piston a moves to the right compressing the spring 6|a until it contacts the stop 62a. As soon as the piston strikes the stop 62a the pressure from passage 64a overcomes the resistance of 'the split rings of the. valve 8| and the valve moves to the left until the rings 92 and 83 partially pass their respective sleeve I openings 95 and 93. At this point the valve 42a tween'the piston and valve 8|, thereby moving the valve still further to completely uncover the sleeve openings, and reverse the application of pressure to the work piston 39a. This operation is; of course, substantiallyinstantaneous and the pressure is not increased above the predetermined work pressure.

With the valve in this latter position, the pressure is applied from the pressure passage 31 through conduit 98, the sleeve openings 99, valve passage 85, sleeve openings 95 and the conduit 94 to the left hand end of the work cylinder 38a, thereby returning the piston 39a to its normal position. During this movement of the piston 39a the oil in the right hand end of the cylinder 98a freely moves throughthe conduit 92, sleeve openings 93, valve passage 88, and returns to I the reservoir 6 through the return conduit 86a.-

As soon as the piston 39a returns to its normal position illustrated,' the pressure in the pressure passage 31 again opens the valve61, admitting pressure to the channel 64a and to' the right hand end of the control valve 8|. This pressure first moves the piston 60a against the stop 62a again compressing the spring 6|a and then moves the valve 8| to the left.' 'During this latter movement, the outwardly extending end 9| of the control valve pushes the auxiliary valve 81 also to the left until the ports 91 are partially opened, thereby again relieving the, pressure. The compressed spring 6| a acting on the piston 60a and the fluid intervening between the piston and valve then moves the-valve 8| and auxiliary valve 91 still farther to the left to completely open the ports 91. The fluid then flows freely through the ports 91 and the return condlit IBM to the reservoir 6. In this latter position, it will be apparent that the pumping pistons may continue topperate with the result that there will 1 to use as high a pressure asin the work stroke,

and adjustable means is provided whereby the pressure may be limited as found desirable in accordance with the weight and frictionoi. the piston. An auxiliary duct 94a connects the channel 94 with the duct 64a, and this auxiliary duct is normally closed by an adjustable yielding needle valve 941). This valve may .be similar to --valve 61; however, it may be adjusted to open at a much lower pressure, thereby operating the lar adjusting means is of course applicable to the embodiment illustrated in Fig. 5.

It should be particularly noted that in the embodiments illustrated,'there are no separate pipes or conduits and no couplings or other similar devices. All of the fluid conduits or channels, as well as the valve and piston'cylinders, may be provided merely by boring, drilling, or otherwise machining suitable passages in a single block of material.

It is believed thatthe present invention provides a device capable of developing a higher working pressure with a smaller machine and the present drawings are one-half size and Fig.

- minute.

is full size of machines now in actual use, and

these machines are capableof developing more than 5,000 pounds working pressure at 1200 R. P. M. with a M; H. P. motor and-operating a world-applying piston 150 or more times per The advantages of the device will be readily appreciated when it is understood that the size of the casing of the unit developing the above noted power is only 6 x 7" x 12".

An important feature of the present-invention is that no pressure is generated higher than the pressure applied to the work and no appreciable *pressure is ever generated except at the time of application to the work. The control valve may operate at apressure considerably lower than the wo'rk'pressure. A dial or other indicating device such as illustrated in Fig. 14 may be provided for the adjustable valve at. The thumb screw ll may be arranged to rotate a pivotally mounted dial via by means of a pinion lib secured to the thumb screw shaft and meshing with a gear lie on the dial. I

The smallsize and low cost of the device relative to the energy developed make it particularly desirable for use in connection with presses already installed, as it may be located adjacent thereto or supported within or on the frame, as shown in Figs. "land 8, and saves the cost of installation of a new machine. In Figs. "'1 and 8 the unit i may be mounted on any suitable part of an ordinary press frame I02; for instance'itmay be supported on ashelf I03 or it may be supported entirely within the frame. The motor it may also be mounted in any suitable manner within the frame of the press and may drive the flywheel i2 by means of a belt I04 on suitable pulleys. The unit is oper-v atively connected to a pressure cylinder'iiii by means of the conduits 92 and 9d, and when a spring is used to return the work piston the,

conduit 98 may be omitted.

The controlling valve of the pressure unit may be manually operated, or any suitable switching arrangement may be used for momentarily connecting the solenoid circuit to a suitable electrical power source.

Modifications may be made by those smiled in the art without departing from the spirit of'the invention, and it is therefore desired that the invention be limited only by the scope of the appended claims.

Having thus described this invention, what is claimed and desired to secured by Letters Patent is: I

1; Ina momentum operated pressure generatconduits for time circulation of I fluid there-' through, the combination with a pump for freely circulating said fluid. oi an independently oper-' able valve for blocking said fluid to enable said momentum to generate a predetermined high pressure in 'said fluid, an energystoring means associated with said valve, and means automatically operable by said predetermined high pressure to direct less'than said predetermined pr essureftomovessaid valve to reduce said high vi3 sure and to store energy in said storing I aiding its ing unit for a hydraulic press, said unit having said] storing means automatically operfor-obstructing said circuit to cause said momentum to create a high pressure in a part of said circuit, means for directing said preessure to a work surface, means for directing said pressure to store energy to move said obstructing means and substantially simultaneously directing said pressure to move said obstructing means to partially relieve said pressure, said storing means being adapted to continue the movemeent of said obstructing means to completely relieve said pressure. g

3. In a press of the character described having a fluid pressure conduit and momentum-controlled means for maintaining a substantially constant flow of fluid therethrough, said conduit having unobstructed communication with a work-performing means, a, movable member for closing said conduit to e nable said momentum to create a high pressuretherein, a fluid-filled icy-pass communicating with said pressure coinduit and with said member, means normally closing said by-pass to trap fluid therein to normally prevent movement of said member to close said pressure conduit, means operable to vent said by-pass and permit movement of said memher to close said pressure conduit, said by-pass closing means being operable at a predetermined high pressure in said pressure conduit to admit pressure to said by-pass whereby said pressure will move said member to open said pressure conduit.

' 4. In a high pressure hydraulic power unit for pressure applying tools, said unit having fluid filled conduits for a free fluid cycle, the combination with power storing drive means for freely circulating said fluid through said con-- duits, of means for blocking one of said conduits to enable said power storing drive means to exert'a substantially instantaneous high pressure in said blocked conduit, a normally closed fluid duct for directing pressure from said blocked conduit to said blocking means to cause said blocking means to reduce the pressure in said 4 blocked conduit, means to open said duct at a predetermined pressure in said blocked conduit and to close said duct with a drop in pressure,

resilient power-storing means operable by presreservoir through said conduits-a reciprocable piston, a movable valve for simultaneously blocking said fluid circulation and directing a predetermined pressure therefrom to one side of said piston, means for directing pressure to move said valve to relieve the pressure from said one side 0isaid piston and direct pressure. to the other side, said last means being automatically operable to again direct pressure to move said valve to permit free fluidcirculation and stop said piston after a single cycle.

6. In a comparatively small pressure generating unit having a momentum controlled circulating fluid circuit, a piston valve slidable to close said circuit to enable said momentum to develop a predetermined fluid pressure, and to direct said pressure to a flrst work conduit arranged to control a work performing means, an auxiliary valve movable simultaneously with said piston valve to obstruct a second work conduit arranged to control a work performing means, means operable at said predetermined pressure in said first work conduit to move said piston valve to release the pressure therein and simultaneously direct the pressure to said second work conduit, and means operable at a predetermined pressure in said second work conduit to move said piston valve to release the pressure in said second work conduit and simultaneously move said auxiliary valve to permit free circulation of said fluid circuit.

7. A press of the character described, comprising an unobstructed fluid circuit including a work pressure chamber for directing pressure to a work performing means. a pump for freely circulating fluid in said circuit, a fly wheel operably connected to said pump, power means constructed and arranged to supply only sumcient energy to said flywheel to maintain a predetermined constant momentum and only sufficient energy to said pump to freely circulate said fluid, movable means for obstructing said fluid circuit between said pressure chamber and the intake of said pump to enable said momentum to create a pressure in said working chamber greater than energy supplied from said power means during the work period, a fluid channel for directing said fluid pressure directly against said obstructing means to open said fluid circuit, and means for venting said channel to said circuit to enable free movement of said obstructing means to obstructing position.

8. In a momentum operated hydraulic press having, conduits for free circulation of fluid therethrough, means operable to block said fluid to enable said momentum ,to generate a high pressure in said blocked fluid, means to enable said pressure to perform work, energy storing means, and means automatically operable at a maximum predetermined pressure to enable energy to be stored in said storing means, said 9. A power unit of the character described. comprising an integral pump and channel block forming one wall of a fluid reservoir, said reservoir being at atmospheric pressure, channels in said block to enable fluid to be freely circulated from and to said reservoir, one of said channels being constructed and arranged to direct fluid pressure therein to a work performing means, a pump in said block and forming a part thereof to freely circulate fluid through said channels, a valve in said block and movable to interrupt the circulation of fluid in said channels to cause the fluid in one of said channels to exert a working pressure against said work performing means, a normally closed fluid filled by-pass channel in said block between said pressure conduit and said valve and arranged to normally cause the fluid therein to prevent movement of said valve, control means operable from outside said block to vent said by-pass and enable movement of said valve to obstructing position, and means operable at a predetermined working pressure to movev said valve toallow circulation of said interrupted fluid.

10. A power unit of the character described, comprising an integral pump and channel block forming one wall of a fluid reservoir, said reservoir being at atmospheric pressure, channels in said block to enable fluid to be freely circulated from and to said reservoir, one of said channels being constructed and arranged to direct fluid pressure therein to a work performing means, a

pump in said block and forming a part thereof to freely circulate fluid through said channels, a piston valve longitudinally movable to interrupt the circulation of fluid in said channels to cause the fluid in one of said channels to exert a working pressure against said work performing means, a normally closed fluid filled by-pass channel between said pressure channel and one end of said valve and arranged to cause fluid therein to normally prevent movement of said valve, said valve having a normally closed longitudinal bore, a vent valve in said bore, means accessible from outside said block to open said vent valve to vent said by-pass and simultaneously move said valve to obstruct said circulating fluid, and means operable at a predetermined workingpressure to move said valve to allow circulation of .said interrupted fluid.

ALLAN A. NORIN. ALBERT M. OLSON.

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