US 3477523 A
Description (OCR text may contain errors)
Novr 11, 1969 E. E. LEWIS HYDRAULICALLY OPERATED TOOL FOR OPERATING UNDER NONATMOSPHERIC PRESSURES Filed March 20, 1968 y .fm/encor:- Zr'nesz: .flew/Is,
United States Patent O 3,477,523 HYDRAULICALLY OPERATED TOOL FOR OPER- ATING UNDER NONATMOSPHERIC PRESSURES Ernest Eber Lewis, Topsfield, Mass., assgnor to General Electric Company, a corporation of New York Filed Mar. 20, 1968, Ser. No. 714,585 Int. Cl. E211) 3/12, 7/12; F01d 15/06 U.S. Cl. 173--163 4 Claims ABSTRACT F THE DISCLOSURE A hydraulically operated tool is provided comprising a case for housing a hydraulic motor, an output device, such as a wrench, means for coupling the hydraulic motor toV the output device, and operating controls for the hydraulic motor. Hydraulic fluid which is supplied to operate the motor is further utilized for equalization of the internal case pressure with the ambient pressure so that the tool can be operated at great depths or high altitudes. In operation, the fluid, after leaving the motor, is first discharged into the case so that the case is filled. To effect pressure equalization, a diaphragm, positioned in the wall portion of the case, acts upon the case fluid to compress or expand the effective volume thereof in response to action thereupon by the ambient pressure.
This invention relates to power tools and, more particularly, to power tools which may be operated either manually or remotely at pressures other than atmospheric.
Submersible tools are well known and have been utilized for a number of various applications. Generally, when operating at rather shallow depths, the primary requirement of such a tool is merely that the case be water' tight so that the interior thereof is not in any way damaged. However, when operating at great depths or high altitudes, the ambient pressure induces very high stresses in the cases and housings for such tools, and effective means must be provided to counteract the effect of such pressure. Prior art devices have generally utilized pressure vessels; that is, vessels effectively isolating the effect of the ambient pressure so that the internal case structure operates independent of and without regard to pressure differences. However, such pressure vessels are necessarily more expensive and more complex than their counterparts which are utilized at atmospheric pressure operation. Furthermore, even when such pressure vessels are utilized, there are often interengageable parts which must sometimes necessarily be removed or substituted so that one or more seals are required to keep the internal structure independent of the ambient pressure. Since a large differential pressure appears across each seal in such a system, generally high quality or specially designed seals are utilized with such devices to provide effective pressure isolation. These requirements of the prior art have generally resulted in rather large cumbersome tools which are rather expensive and rather difficult to manipulate when operated.
It is, therefore, an object of this invention to provide an improved, inexpensive submersible tool operable at pressures varying greatly from atmospheric pressure.
It is another object of this invention to provide a submersible tool which does not require a pressurized case.
It is a further object of this invention to provide a submersible vessel which can operate with ordinary seals.
In accordance with my invention in one form thereof, I provide a power tool comprising a rather simple case for housing a hydraulic motor, an output device, such as a wrench, coupling means for connecting the output of the motor with the output device, and suitable operating controls for the hydraulic motor. Hydraulic uid applied to operate the motor is further utilized for equalization 3,477,523 Patented Nov. 11, 1969 of the internal case pressure with the ambient pressure so that the tool can be operated at great depths or high altitudes. Pressure equalization occurs by allowing the fluid, after leaving the motor, to be rst discharged into the case so that the case is filled. Pressure responsive means are positioned in a wall portion of the case and act upon the case fluid to compress or expand the effective volume thereof in response to the ambient pressure, and thereby, to effect pressure equalization.
The present invention may better be understood by reference to the following description when taken in connection with the accompanying drawings in which:
FIGURE l is an external view of the tool structure and the supply system therefor;
FIGURE 2 is a cross-sectional view of the hydraulically-powered tool of the present invention; and
.FIGURE 3 is a cross-sectional view of the hydraulically-powered tool taken along the line 33 of FIG- URE 2.
While my power tool may be operated under all ambient pressure conditions, ranging from ocean depths to outer space, the following description considers the operation of the tool when it is submerged in water.
In FIGURES 1 and 2, there is shown the hydraulically powered tool 1 of the present invention which comprises a case 3 including a large cavity `4 for housing a hydraulic motor 5, an output device 7 such as a wrench, means 9 for coupling the output of the hydraulic motor 5 to the output device 7, and suitable control means 11 for operating the hydraulic motor 5. Also shown in FIGURE l is a supply source 13 of hydraulic iluid for operating hydraulic motor 5. The source of hydraulic fluid is connected to a pump 14 so that a sufcient pressure differential may be created to operate hydraulic motor 5. The outlet from pump 14 is connected by line 15 to a supply inlet 17 in the case wall. The iluid flows into case 3 and through a conduit arrangement 19 into hydraulic motor 5. The fluid is then discharged from motor 5 into case cavity 4 and, finally, out a case drain outlet 21 and back through line 22 to the fluid supply source 13 so that continuous operation may be effected.
As seen in FIGURES l and 2, case 3 comprises elements which are so interconnected as 'to present an integral body. However, seals, such as those designated 23, must necessarily be provided at particular locations to insure the relative watertightness of the tool. Also, as seen in FIGURE 1, a socket 25 rather than a unitary output device, may =be inserted in a forward aperture of tool case 3 so that it may Ibe coupled with the output of the hydraulic motor shaft 27. The tool of the present invention may comprise a relatively lightweight case 3 and utilize a conventional seal 23 due to a novel pressure equlaization arrangement which creates an internal case pressure equivalent to the ambient pressure when the tool is submerged so that the eifective pressure across case 3 or across seal 23 is negligible.
A major feature of the present invention is the use of hydraulic motor 5 to drive output device 7 and a flow arrangement for the hydraulic fluid which is utilized not only to drive the motor, but to obtain the desired pressure equalization across the seals and the case. Pressure equalization is accomplished by causing the hydraulic fluid flowing into case 3, after it has flowed through motor 5 to drive output shaft 27 thereof, to completely fill the internal volume or cavity 4 of case 3 before it drains back through case drain outlet 21 into return supply line 22.
Of course, it would be expected that the fluid introduced in such an arrangement would normally be at approximately atmospheric pressure. Therefore, novel means 31 are provided to expand or contract the effective volume of the fluid within case cavity 4 in response to the ambient pressure at any depth or height and, thereby, to lower or raise the effective internal case pressure in response to such fluid volume variation. The pressure equalization means 31 takes the form of pressure responsive diaphragm 33 which is positioned in a portion of the case wall, exposed on one side 35 thereof to the surrounding atmosphere and pressure thereof, and exposed on the other side 36 to the hydraulic uid within case cavity 4 and the pressure generated thereby. Diaphragm 33, being responsive to both the internal case pressure and the external ambient pressure, is caused to move until the volume of fluid within case cavity 4 is altered to such extent that the internal case pressure equals approximately the ambient pressure.
Since it is known that the hydraulic oil selected will compress as a function of its bulk modulus, it is necessary to select diaphragm 33 on a basis to cover the dimensional changes over the complete range of pressures expected and still remain within its functional tolerance.
Diaphragm 33 need not be the simple configuration as shown. It might, for example, attain a cup shape for some applications.
Since the hydraulic liuid filling case cavity 4 is in a dynamic state and returns to supply source 13 through case drain outlet 21, it can -be seen that the Supply fluid is always at the reference pressure. Thus, the hydraulic pump requirements remain essentially only those to account for the necessary hydraulic motor pressure drop and line friction which has some effect on the effective pressure. Obviously, the pump requirements will increase over long line lengths but can be minimize-d with proper choice of line sizes and flows over the depth range expected.
In addition to the pressure equalization means described above, there is provided a hydraulic control System 11 which controls the direction of motor operation and the operating speed of the hydraulic motor. Hydraulic control system 11 includes a pressure compensated flow control valve 37 and a transfer valve 39. The flow control valve 37 is provided for regulating the uid flow rate and, hence, the output speed of hydraulic motor 5, through the system. Transfer valve 39 is provided to control the direction of fluid flow through motor so that it is reversible. Manual control means 41 and 43 attached to a handle 51 are provided to control the operation of flow control valve 37 and transfer valve 39, respectively. Both valves 37 and 39 and control means 41 and 43 are conventional and well known in the art and the particular str-uctural configurations thereof are not part of the present invention.
As can be seen from FIGURE 1, fluid flows from supply source 13 through pump 14 and into case 3 via supply line and case inlet 17. The fluid, once in the case, flows in conduit arrangement 19 into pressure compensated flow control valve 37 for regulating the fluid flow rate to hydraulic motor 5. After the hydraulic fluid has been discharged from ow control valve 37, it flows into transfer valve 39 and one of two lines, designated and 47, determined by the position of manual control means 43. In the normal off position, each line leading into hydraulic motor 5 is closed off. Depending upon which direction o-f rotation is desired for output shaft 27 of the hydraulic motor, manual control means 43 is operated, as seen FIGURE 3, to open one or the other of the lines 45 and 47 to the high pressure, at the same time opening the other to the drain side, so that the hydraulic uid may be directed into and out of the hydraulic motor 5.
After the uid has moved through motor 5 to operate motor output shaft 27, it is discharged through a suitable outlet port 49 in themotor housing into case cavity 4. By proper dimensioning of the motor outlet 49 and case drain outlet 21, case cavity d is completely filled 4by the hydraulic fluid after it flows through motor 2, and pressure equalization can be accomplished by the aforemenarmszs y tioned diaphragm arrangement. The hydraulic uid leaves case 3 through the drain line which also serves as the return line to the supply source of hydraulic fluid so that the system requires only a finite amount of Huid continuously circulating through the tool.
Since the internal case pressure is equal to the ambient pressure, it is important to ensure that, upon Vraising the tool to the surface, if it is submerged, no high pressures become trapped while at great ocean depths., Thus, the components 'and design must be such as to ensure this fact. In this case, the seals and cavities shouldn be designed and oriented to allow the contained pressure to change as the ambient pressure'clianges when returning to the surface.
As was stated previously, the fluid flow rate is regulated by flow control valve 37 within case 3. In a preferred form of the invention, output shaft 27 of hydraulic motor 5, which rotates at the predetermined speed as determined by the pressure compensated fiow control valve 37, is connected to a suitable tool such as wrench 25 by coupling means 9 in the form of an inertia-clutch arrangement. The basic principle of such mechanism is well known; that is, the spinning of an inertia mass to a given speed and then directly clutching this mass to the output device, such as the wrench. The momentum of the mass is thereby converted into impact torque. The size of the mass and its speed, as well as the stopping time, determines the impact torque output of the wrench. The type of impact arrangement used in this invention employs a conventional cam operated clutch (not shown) to engage the rotating mass with the output shaft. In this type of arrangement, the mass is accelerated to the desired speed, at which time a cam forces the mass to engage the output shaft thereby causing the impact.
It takes only a small amount of torque to bring this inertia mass up to speed, because this can occur over either one revolution or several revolutions, but the very fast stopping time as it is clutched to the output shaft can produce large output torques. As was stated previously, the pressure compensated flow control valve 37, which sets the oil flow to motor 5, effectively controls the wrench impact torque. I also provide additional fine adjustment means to control the impact torque comprising a manually operated needle Valve 53 positioned in a bypass across pressure compensated ow control valve 37 formed by conduits 55, 57. Valve 53 is adjusted by rotation of hand grip 59 in a conventional manner. The transfer valve 41 which controls the direction of oil ow to the motor serves to direct the output torque of wrench 25.
I have thus described a hydraulically operated tool which may be used at widely different ambient pressures. The tool utilizes hydraulic fluid supplied to the hydraulic motor within the case for filling the case and accomplishing pressure equalization between the internal case pressure and the ambient external pressure. This is accomplished through a diaphragm in a wall portion of a case which varies the volume of an effective pressure of the hydraulic fluid within the case in response to the ambient pressure.
One of the advantages of my improved tool is that it requires no external support but can be carried by hand and manually operated. This is particularly attractive for outer space uses. Alternatively, for operating at great ocean depths the tool can be attached to a submerged vessel, such as a submarine, and operated by a manipulator attached to controls 41 and 43. Under submerged c-onditions the tool appears substantially weightless and transfers only a low reaction torque to a diver holding it or to the maneuvering vessel. This feature also permits it to be used in an essentially zero g environment such as outer space.
While the invention has been described with specificity, it is the aim of the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.
5 What I claim as new and desire to secure by Letters Patent of the United States is:
`1. A hydraulically operated tool for operating under a wide range of ambient pressure conditions comprising:
a case having a cavity therein and including an inlet and an outlet to said cavity;
a hydraulic motor within said case cavity, said motor including a rotatable shaft and a housing having an inlet and outlet communicating with said cavity;
an output device drivingly engageable by said rotatable shaft;
means for connecting said case inlet with a source of hydraulic fluid at a predetermined pressure;
means for connecting said case outlet to said hydraulic iluid source;
means connecting said case inlet with said motor housing inlet for delivery of hydraulic fluid thereto;
said motor housing outlet and said case outlet being so dimensioned that iluid leaving said motor housing outlet is discharged into and lills said cavity before draining through said case outlet; and
a pressure responsive means disposed in a wall portion of said case and exposed on one side thereof to the ambient pressure and exposed on the other side thereof to the hydraulic fluid within the case cavity for equalizing the pressure within said case, with the ambientpressure surrounding said case. 2. The hydraulically operated tool as recited in claim 1 wherein said pressure responsive means comprises a diaphragm.
3. The hydraulically operated tool as recited in claim 1 wherein said conduit means further includes ud control means operable to control the direction of rotation of the rotatable shaft of said hydraulic motor.
4. The tool of claim 1 which includes a handle and controls for manual operation of the tool.
References Cited UNITED STATES PATENTS 2,904,964` 9/ 1959 Kupka 175-6 3,417,566 12/1968 Gould 173--163 JAMES A. LEPPINK, Primary Examiner U.S. Cl, X.R. 175-6; 253-2