US2677238A

US2677238A - Hydraulic motor and system

Info

Publication number: US2677238A
Application number: US90879A
Authority: US
Inventors: Edward M Greer
Original assignee: Greer Hydraulics Inc
Current assignee: Greer Hydraulics Inc
Priority date: 1949-05-02
Filing date: 1949-05-02
Publication date: 1954-05-04
Anticipated expiration: 1971-05-04

Description

INVENTOR.

JEDW/I/PD M 5565/? BY J 2 May 4, 1954 E. M. GREER HYDRAULIC MOTOR AND SYSTEM Filed May 2, 1949 3mm. VOAuME- ///6// Nassau FLU/0 Jaw/2y Patented May 4, 1954 HYDRAULIC MOTOR AND SYSTEM Edward M. Greer, West Hempstead, N. Y., as-

signor to Greer Hydraulics, Inc., Brooklyn,

Application May 2, 1949, Serial No. 90,879

4 Claims.

This invention relates to fluid operated power motors and their operating system and more particularly to the operation of a single fluid motor that is connected to a common fluid pressure supply in combination with a plurality of similar motors.

This application is related to my co-pending application Serial No. 728,516 filed February 14, 1947, now Patent No. 2,487,126, dated November 8, 1949.

In the past where a plurality of fluid motors have been connected to a common fluid pressure supply, to operate one fluid motor there is ample fluid pressure available. Where a plurality of fluid motors are operated simultaneously from a common pressure source, especially when many power strokes are produced simultaneously this might produce an undesirable condition in which the actual power supplied would be below the predetermined pressure'required for the operation of each motor.

It is an object of this invention to utilize a fluid storage accumulator in combination with each motor where a plurality of fluid motors are connected to a common fluid pressure operating supply to insure adequate operating pressure for each power stroke of the motor.

A further object of this invention is to provide a fluid storage means in combination with a hydraulic motor where a plurality of fluid motors are connected to a common fluid pressure supply and in which a manual control valve is provided to connect both the fluid storage means and the common pressure supply to the motor for each power stroke.

Another object of this invention is to provide an individual hydraulic system for each hydraulic motor where a plurality of fluid motors are connected to a common fluid pressure supply which includes a fluid pressure storage means connected to said motor by means of a manually operated valve and in which a normally open sequence operated valve is interposed between the storage means and motor, said sequence valve being closed by a predetermined maximum pressure to prevent charging fluid into the fluid storage means during the operating stroke of the motor.

A further object of this invention is to provide means to utilize a small volume high pressure fluid pump in combination with a plurality of accumulators and check valves to store sufficient hydraulic fluid under pressure in each accumulator and retain said pressure by means of a check valve said accumulator being utilized to produce the work positioning stroke-of the hydraulic cylinder and when the hydraulic cylinder has been positioned in its working position, the high pressure fluid flow from said pump may be utilized to produce the power stroke of said cylinder, the small volume high pressure fluid pump producing a static force maintaining a working pressure on the hydraulic cylinder.

Another object of this invention is to provide a single small volume hi h pressure fluid pump connected to the individual hydraulic system of each of a plurality of motors in which a check valve is interposed between the supply system and the individual system of the press to permit flow from the supply system to the individual system but not vice versa and in which a fluid storage means in each individual system is normally charged to a predetermined pressure and in which a manually operated valve is utilized to connect the storage means to the motor to permit a large volume flow of fluid for positioning the work cylinder of the motor and subsequently the high pressure flow from the pump for the power stroke of said motor and subsequently by means of said valve means to close said power supply to said motor and allow said motor to dump the fluid and return the work positioning cylinder to its initial position and at the same time permit said pump to charge the storage means to a predetermined pressure.

Other objects of this invention will be apparent by referring to the detailed description of this device and its operation, as well as the accompanying drawing in which:

Fig. 1 is a diagrammatic layout of a fluid press and its individual hydraulic system that may be connected to a common fluid pressure supply,

Fig. 2 is a cross sectional view of the pilot operated valve, and

Fig. 3 is an alternate diagrammatic layout of a fluid cylinder and operating valve.

Referring to Fig. 1 there is illustrated a power press in with a hydraulic cylinder M. Th hydraulic cylinder 14 is provided with a piston I5 that in a work position bears against a platen or plate I6 of the press. The hydraulic cylinder I4 through a port I! is connected by means of a line IB to a rotary selector valve 19, the selector valve l9 being provided with three ports I, 2, and 3, port I being connected to the line 18, port 2 being connected to a return line 20 and port 3 being connected to a pressure supply line 2|, the supply line 2| being in turn connected to a check valve 23 and the opposite end of the check valve in turn being connected to the main pressure line P. The line 21 by means of a T coriting snugly with the bore 31.

3 nection is also connected through a line 25 to one port of a pilot operated valve 26. The pilot operated valve 26 is provided with three

ports

4, 5, and 6, line '25 being connected to port 4 of the valve. Port 6 of the valve is connected by means of line 21 to the line l9 through a T connection. Port 5 of the pilot valve 26 is connected by means of a line 29- to a fluid storage accumulator 39, the accumulator 39 being a hollow shell structure with an oil port I at one end thereof and an air port 8 being connected toa bladder 9 mounted within the accumulator shell. An auxiliary line 3| is connected below the oil port 1 to the line 29 and in ,turn connectedto a check valve 32. The opposite end of: the check valve is connected by means of a line 33 to the line 25. The selector valve 19 may be positioned in either of two positions. In the position illustrated, the valve l9 will provide a communicating passage between line 2| and line I8 while the valve l9 in its other position (illustrated in dotted lines) will provide communication between line l8 and line 29. Thus, the valve IS in one position permits chargin the hydraulic press .for a, positioning stroke and power stroke while the valve I9 in the other position permits the hydraulic press to discharge and allow the hydraulic iston to be restored to an open position (as illustrated in this figure the cylinder l5 will .assume an open position by gravity) Referringto Fig. 2 there is illustrated the pilot valve 26 which is generally barrel shaped. The

.valve 26 is comprised of a body member 36 with a central bore 31, the bore 3? being provided with an enlarged end bore 38. A pair of ports 4 and .5 are provided through the body 36 and are psitioned in a staggered relationship to each other connecting the exterior of the body 36 with the central bor 37. A plunger 39 is provided to lit the bore 31. The plunger 39 is provided with a central section 40 of smaller radius than th bore 31 to thus provide a cutout portion in the center of plunger 39, both ends of the plunger 39 fit- The end of the plunger 39 may be provided with seals 4| and 42. One end of the plunger 39 is provided with ya spring seat 44 and a spring 45 is mounted thereon. The opposite end of the spring 45 abuts against a plug 46, the plu 46 being threadably secured in the body 36 as illustrated. The plug 46 is provided with a cutout portion 41 to permit adjusting the position of plug 46 and thus in turn adjusting the compression of sprin 45. In the bore 3? at the opposite end thereof there is provided a lock ring groove 59 and when the plunger 39has been mounted within thebore 31, a circular snap ring 50 is compressed and passed through bore 37 and allowed to snap into the groove50 to form a stop for the plunger 39. The bore 3'! at the lock ring end is threaded to form the port 6. Thus, it is apparent that the valve 26 in its normal position permits a fluid flow between port '4 and port but when port 6 is connected to a fluid line and suiflcient fluid'back pressure is exerted through port 6, the plunger 39 will be forced to the left (as illustrated in Fig.

2) until port 4 is sealed off by the plunger to thus prevent the flow of fluid between

ports

4 and 5. When the back pressure through port 6 is released, the plunger 39 will be returned to the position illustrated in Fig. 2 by means of the resilient spring 45. It is also apparent that spring 45 may be calculated for a definite pressure value on plunger 39 and it'may be easily adjusted by means ofplug 46 to obtain an ,exactpressure up through line 33,into the accumulator.

value in port 6 to cause the valve to close port 4.

Referring to Fig. l we may follow the general operation of the single press l0 illustrated although we must assume that this press is only one of a plurality of presses in which each individual hydraulic system as illustrated in Fig. 1 will be connected to a single pressure source P. .The press ||l has been illustrated as a gravity return although any press'may be similarly connected and as in our prior application changes 'may be readily made to provide a pressure return to obtain a similar result. With the system as described above we may assume a predetermined fluid pressure is provided on the main supply line? and referring to my related application mentioned above we may further assume that this is a high pressure supplied from a small low volume pump. Thus the fluid pressure from P will pass through the check valve 23 being charged into the presssystem as illustrated in The fluid pressure from check valve 23 is charged into the line 2| and with thevalve l9 in the position illustrated in dotted lines, line Therefore,

line 25 to the port 4 through the normally opened sequence valve 26 out port 5 through theline 29 .and.be,charged'through port |;into the .accu- -mulator 3|] and will continueto-fill and charge the accumulator 3|] pressing the airbladder 9 and deforming the bladder 9 depending upon the .airpressure charged in the bladder 9 until the accumulator 39 is fully charged at apredetermined pressure which is equivalent to thepressure supply'P. With the accumulator 30 fully charged, we are ready to operate the hydraulic press In. It may be assumed that witha large piston l5 it is necessary to havea large fluid volume flow at a low'pressure quickly to'position the piston l5 into a work position, thusmoving valve l9 to the position illustrated in Fig. 1. Since we cannot obtain a large volume flow from the supply-system P, we do obtain the large fluid volume flow that is necessary from the accumulator 30 through line '3 lthrough' check valve 32 through line 33 throughline 25 through line 2| through port 3 of valve |9 out port I through line l6 into the p0rtl1 of the press charging the press cylinder and forcing it into its work position. Thus with-thejpistonl5in its working position, we no longerneeda large volume flow of fluidand the high -pressure low volume-flow that is continually available-at P will be charged into this supply line -2| and I8. The pressure developed on a non-compressible fluid produces'the power stroke on the piston 15. -When the pressure in line [8 has'inoreased to a predetermined pressure setting .in the sequence valve 26, the fluid pressure ,throughline 21 through port 6 closes the sequence valve 26 to close the port 4 of the valve and thus preventthe high pressure charged from the pump to-back up-into the accumulator. Due to the check valve 32, the fluid pressure cannotback Thus the highpressure is exerted only on the piston H of the press In toproduce the power stroke.

It is apparent that having completed the power stroke of the press that valve I9 may be moved to .the dotted position illustrated and thus the accumulator 39 will again be charged as described and at the same time with valve IS in a discharge position for the press, the piston 5 will drop by gravity forcing the fluid in the piston chamber out through port H at ,a low pressure .througheline |8 through port I of the valve l9 out port 2 through line 20 to the return line and back to the reservoir (not illustrated).

In Fig. 3 there is illustrated a still further embodiment of this invention in which the hydraulic system illustrated in Fig. 1 is connected to a four way rotary selector valve and fluid cylinder that require fluid pressure for operation in both directions. With a rotary valve 5!] connected to line 2! and the valve 58 in turn being connected by line l8 to one side of a cylinder MA while the opposite side of the cylinder I 4A is connected by means of a line 5| to the opposite port of the valve 50. The valve 50 is a three position rotary selector valve having a neutral or intermediate position in which all ports are disconnected or shut off. The position illustrated in Fig. 3 in solid lines will provide a connecting channel 52 in the valve to connect line 2| with line I8 while another connecting channel 53 connects line 5i with the return line 20. In the third position of valve 50 illustrated in dotted lines, channel 52 will connect line 2| with line 5| while channel 53 will connect line l8 with the return line 20. The fluid cylinder MA illustrated is similar to cylinder M of Fig. 1 except that it is provided with two fluid ports, port ITA at one end thereof and port 55 at the other end thereof. The operation of the fluid cylinder [4A may be readily followed by referring to Fig. 3. With the fluid under pressure supplied through line 2| and the valve 50 in the position illustrated in Fig. 3, the fluid will pass through the channel 52 through line It into port I 1A thus forcing the piston I5A to the left (Fig. 3) and any fluid that may remain within the piston cylinder on the lefthand side of the piston will be forced out the port 55 through line 5| through the channel 53 of the valve and out the return line 20. To release the fluid pressure and restore the fluid motor to the position illustrated in Fig. 3, the operating handle of valve 55 must be moved to the dotted position illustrated. In this position the fluid pressure from line 2! will pass through channel 53 through line 5| through port 55 into the piston cylinder of the fluid motor [4A forcing the piston I5A to the right and at the same time, the fluid within the piston cylinder to the right of the piston will be forced out port HA through line l8 through channel 53 and out the return line 20. The third or neutral position of valve 50 is utilized when the press or fluid motor MA is at rest and while the valve 50 remains in a neutral position, the fluid from P will be charged through the check valve 23 and line 25 as already described in Fig. 1 to thus recharge the accumulator or fluid storage means 35.

Having described the apparatus and a complete sequence of operation according to Fig. 1, it is apparent that the press may be replaced by any fluid motor operated device and in combination with its hydraulic system for operation may be modified in any way as long as a sufficient volume of fluid at a given pressure is supplied to position the press or fluid cylinder and a second high pressure of small velocity is supplied for utilizing the pressing or power operation without departing from the spirit of this invention and this invention shall be limited only by the appended claims.

What is claimed is:

1. A system of the character described for operating a hydraulic motor of the type having a cylinder with an inlet and a piston slidable in said cylinder, said system comprising a small volume high pressure fluid supply, a pressure accumulator having a fluid port, a normally open pressure controlled valve having an inlet port connected to said fluid supply, an outlet port connected to the accumulator fluid port, and a second inlet port connected to the inlet of said hydraulic motor to apply pressure to said valve to close the latter when the pressure in said hydraulic motor has risen to a predetermined amount, a selector valve having an inlet port, a discharge port and a control port, means connecting the fluid supply to said selector valve inlet port, mean connecting said accumulator port to said selector valve inlet port, a one way valve permitting flow only from said accumulator port to said selector valve inlet port, and means to set said selector valve to connect said control port to said discharge port, whereby said accumulator will be charged substantially to the pressure of said fluid supply, and to set said selector valve to connect said inlet port to said control port, whereby fluid both from said accumulator and said fluid supply will flow into said hydraulic motor quickly to move the piston to operating position and upon rise in pressure in said motor to the setting of said pressure controlled valve to closethe latter, and upon continued flow of the high pressure low volume fluid from said fluid supply, further to move the piston.

2. The combination set forth in claim 1 in which the hydraulic motor is of the gravity return type, whereby upon setting of said selector valve to connect the control port to the discharge port, the piston will return to retracted position with resultant drop in pressure in said hydraulic motor and opening of said pressure valve and fluid will flow from the fluid supply to the accumulator to charge the latter.

3. The combination set forth in claim 1 in which said pressure valve comprises a cylindrical casing having a longitudinal bore therethrough, and a pair of radially displaced bores extending into said longitudinal bore on opposed sides thereof defining the inlet and outlet ports, one end of said longitudinal bore defining the second inlet port, a

' inlet port comprises a coil spring in said longitudinal bore, and means are provided to adjust the tension of said coil spring.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 780,614 Nash Jan. 24, 1905 15150372 Irish Apr. 3, 1923 1,982,711 Vickers Dec. 4, 1934 2,214,817 Harrington Sept. 17, 1940 2,239,566 Mercier Apr. 22, 1941 2,264,375 Hill et al. Dec. 2, 1941 2,549,897 Evrell Apr. 24, 1951 2,579,116 Hirvonen Dec. 18, 1951