Apparatus For Transmitting Force By Hydraulic Pressure

Abstract

A hydraulic pressure transmitter is connected by a flexible tube to a hydraulic actuator. The transmitter has a flexible bellows, with a closed outer end, whose interior defines a first chamber, has a cylinder, and has a piston reciprocable in the cylinder and defining therewith a second chamber, communicating with the bellows, and a third chamber communicating with the tube. The closed outer end of the bellows has a pressure plate thereon which is engaged by an operating button which can be depressed to collapse the bellows. A piston rod is secured to the closed bellows end and extends through a perforated rigid diaphragm into the second chamber, the inner end of the piston being shaped to sealingly engage in an aperture in an end wall of the piston. The piston is biased toward the piston rod by a spring, and has a small clearance with the cylinder walls for flow of hydraulic fluid therepast between the second and third chamber parts.

Parent Case Text

This is a continuation application Ser. No. 169,771 filed Aug. 6, 1971, now abandoned.

Description

FIELD OF THE INVENTION

This invention relates to apparatus for transmitting force by hydraulic pressure and, more particularly, to a novel, simplified and improved manually actuable force transmitting apparatus utilizing hydraulic pressure.

BACKGROUND AND SUMMARY OF THE INVENTION

There is a demand for mechanism for transmitting force, by hydraulic pressure, from one point to another and irrespective of the states between the two separated points. Such a hydraulic pressure transmitting apparatus is especially useful for remote control of adjustment means for selecting and fixing the inclination of seat backs in airplanes and the like.

In accordance with the invention, the force-transmitting apparatus comprises a pressure-applying component and a force-transmitting component interconnected by a flexible tube. The structure is designed in a way such that, by pushing a button of the pressure-applying component, a plunger of the force-transmitting component, or hydraulic fluid actuator, is projected by the hydraulic fluid confined within the pressure-applying component, the force-transmitting component and the tube. Thus, a force is transmitted to an object attached to the force-transmitting component and to which the force is to be applied.

An object of the invention is to provide an improved apparatus for transmitting force by hydraulic pressure.

Another object of the invention is to provide such an apparatus which is particularly adapted to the remote control of parts to be moved.

A further object of the invention is to provide such an apparatus which is simple in construction, economical to manufacture and readily adaptable to various applications.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

FIG. 1 is a side elevation view of apparatus embodying the invention;

FIG. 2 is a longitudinal sectional view corresponding to FIG. 1;

FIG. 3 is a plan view, partially broken away and partially in section, of the pressure-applying component;

FIG. 4 is a sectional view taken along the line X--X of FIG. 2; and

FIG. 5 is a sectional view taken along the line Y--Y of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing, the apparatus is actuated responsive to pressing of a button 1 which is movably mounted in a button receiving aperture of a style strip 2. A button engaging pressure plate 3 is secured to the closed outer end of a bellows 5, whose open inner end is clamped between a radially extending seat of a main body 6 and an annular retainer 7. A piston rod 4 is secured to the closed outer end of bellows 5 and extends through a rigid, perforated circular piston rod guiding washer or diaphragm 8 seated in the body member 6 and engaged by the inner end of bellows 5.

A hydraulic fluid or oil chamber is formed by bellows 5 and main body 6, and is divided into three parts a, b and c by washer 8 and a piston 9 reciprocable in a part of body 6 forming a cylinder. Chamber part a is formed by bellows 5 and perforated washer 8, which has a central aperture through which piston 4 extends in guided relation and, radially outwardly from this aperture, several holes or additional apertures for the flow of hydraulic fluid between chamber parts a and b. Chamber part b is defined by washer 8 and an end wall of piston 9, and chamber part c is defined by the cylinder of body 6 and the inner end of piston 9. Circular washer 8 acts as a guide for piston rod 4. It will be noted that piston rod 4 extends completely through chamber part a and, through circular washer 8, into chamber part b. The chambers a and b are in constant substantially unrestricted communication through the perforations in the member 8 which guide the piston rod 4.

The inner end of piston rod 4 is conical and is arranged to sealingly engage in a central aperture in the end wall of piston 9. Piston 9 is constantly biased by a spring 10, fitted in chamber part c, toward piston rod 4. Each chamber part a, b and c contains hydraulic fluid, and chamber part c communicates with the inerior of a flexible tube 12 which is secured to body part 6 by a coupling element 11, an O-ring 13 providing a fluid-tight seal at the inner end of coupling element 11. A similar coupling element 11, with another O-ring 13, connects tube 12 to the fluid pressure actuator, and tube 12 is enclosed in a protecting tube 14. The other end of tube 12 communicates with a bore in the main body 15 of the fluid pressure actuator. Both ends of protective tube 14 are press-fitted into the respective couplings 11 to help anchor tube 12 in the tube coupling elements.

Body 15 of the force-transmitting component or fluid pressure actuator is formed with a passage, for the flow of hydraulic fluid, extending from coupling 11 to a compartment d forming a hydraulic fluid chamber. Compartment d is formed by an annular recess in body 15, and is closed by a double diaphragm 16, 17, with a spring seat or plunger 18 engaging the outer surface of diaphragm 17. The diaphragms are clamped in position by a clamping ring 19.

Plunger 18 carries, centrally, a bearing member 24 for pushing against the member to which force is to be transmitted. A spring 20 has one end seating in an annular groove in the outer face of plunger 18 and its other end seated in a groove in the inner face of a guide 21 which is held in position by caulking an outer edge f of body 15 over a rim on the inner edge of guide 21. An annular spring 23 is interposed between clamping ring 19 and guide 21, and guide 21 is provided with setscrews 22 for connection thereto of the object to which force is to be transmitted. Annular spring 23 permits angular adjustment of guide 21 during its fitting to the part to which force is to be transmitted.

Style strip 2 has a depending skirt 2a on which are mounted a washer 25 and a spacing spring 26 which assists in mounting style strip 2 on the part to which it is to be attached. Skirt 2a is telescoped into a cup-shaped member 28 which has a central opening fitting over the body member 6, and cup-shaped member 28 is secured in position by a snap spring 27 engaged in an annular groove in body 6. Skirt 2a is prevented from displacement from cup-shaped member 28 by a spring clip 29 interengaged with parts 2a and 28. The arrangement is such that style strip 2 is rotatable with respect to body member 6.

A threaded plug 30 is engaged in the outer end of an axial bore 4a in piston rod 4, and bore 4a communicates with chamber compartment a. When the device is to be filled with hydraulic fluid, plug 30 is removed and, after refiling with hydraulic fluid, is replaced.

The outer end of the passage in body member 5 is sealed by a copper ball 31, and an airvent hole or bleed port, communicating with chamber d, is closed by a coppper ball 34 held in place by a threaded plug 33, the bleed port being opened during filling of the apparatus with hydraulic fluid to assure a solid hydraulic connection extending from bellows 5 to chamber d.

In the operation of the apparatus, when button 1 is pushed it moves inwardly to collapse bellows 5. By virtue of piston rod 4 being secured to button receiver 3, the piston rod is pushed inwardly so that the oil in chamber compartment a is forced out into the chamber compartment b through the passages in washer 8 and through the guide passage for piston rod 4. Oil under pressure is thus forced into compartment b simultaneously with the depression of piston rod 4 which, in turn, forces piston 9 downwardly. Forcing piston rod 9 downwardly decreases the volume of oil chamber compartment c, and the hydraulic fluid in compartment c is forced under pressure into compartment d through tube 12 to force diaphragm 16, 17 to the right. This projects plunger 18 whose force is exerted on the object to which the force is to be transmitted.

On the other hand, while the hydraulic fluid forced out of compartment c is delivered under pressure to compartment d, at the same time a portion of the oil will return to compartment b through the clearance between piston 9 and the cylinder formed in main body 6, so that balance of the hydraulic fluid will be restored. If the force exerted on button 1 is terminated, spring 20 will force plunger 18 to the left, this action being assisted by the spring 10 which biases piston 9 upwardly. The hydraulic fluid in compartment d returns to compartment c through tube 12. In compartment c, piston 9 is biased upwardly by spring 10, as stated, expanding compartment c to receive the hydraulic fluid returning from compartment d. Piston 9 lifts piston rod 4 to restore, to its initial expanded position, bellows 5 whose upper end is united with piston rod 4. The volume of compartment b is reduced by the upward movement of piston 9, so that hydraulic fluid therein is returned fully to the interior of bellows 5 or, respectively, into the compartment a through the apertures in washer 8 and the guide aperture for piston rod 4.

The hydraulic fluid forced out of compartment b is too great a quantity with respect to the capacity of compartment a, and the resulting superfluous hydraulic fluid is returned to compartment c, through the clearance between piston 9 and its associated cylinder in body 6. The hydraulic fluid in compartment b, when compressed by piston 9, restores compartment a and bellows 5 to their original position, and piston 9 is separated from piston rod 4 by the surplus hydraulic fluid resulting in disengagement of the conical end of piston rod 4 from the central aperture in piston 9, so that hydraulic fluid may flow between compartments b and c as well as through the clearance between piston 9 and the cylinder in body 6. When the surplus hydraulic fluid has all been returned to oil chamber compartment c, the conical tip of piston rod 4 is again engaged in the central aperture in piston 9. As bellows 5 is expanded, button 1 is returned to its initial position.

From the foregoing description, it will be clear that, in the pressure-applying part, there are formed three compartments a, b and c of the hydraulic fluid chamber, and when the upper or outer end of bellows 5 is depressed, the central aperture in piston 9 is blocked by the conical tip of piston rod 4, piston 9 acting as a separation between compartments b and c. This action prevents the internal pressure in chamber compartments a and b from an abrupt increase, even with a rapid increase in the internal pressure in compartment c and, at the same time, enables a slow return of the bellows. Pressure exerted on the pressure-applying part rapidly increases the internal pressure of compartment c to prompty transmit force to the force-transmitting part or hydraulic actuator. However, inspite of this immediate force transmission, any abrupt change of the internal pressure of the bellows 5 can be prevented by adjustment of pressure due to the structure of the pressure-applying part, thus precluding the possibility of sudden deformation or breakage, as well as the possibility of leakage of hydraulic fluid. Consequently, the device has the pronounced advantage of stability and durability.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

What is claimed is:

1. Apparatus for transmitting force by hydraulic pressure comprising, in combination, a hydraulic pressure transmitter; a hydraulic pressure actuator; a flexible tube interconnecting said transmitter and said actuator; said transmitter including a flexible bellows having a closed outer end and an open inner end; a perforated rigid piston rod guiding diaphragm engaging the inner end of said bellows and defining, with said closed outer end and the interior of said bellows, a first chamber; means forming a cylinder having one end connected to said diaphragm; a piston reciprocable in said cylinder and defining therewith and with said perforated diaphragm a second chamber in constant substantially unrestricted communication with said first chamber through the perforations of said diaphragm; said piston defining, with said cylinder, a third chamber communicating with said tube; and a piston rod secured to said closed outer bellows end and extending through said first chamber and, in guided relation centrally through said diaphragm, into said second chamber; said piston having an aperture in an end wall facing said second chamber, and said piston rod having an inner end engageable in said aperture to seal the same; whereby, when a pressure is applied to said closed outer end of said bellows, the inner end of said piston rod sealingly engages in said aperture to move said piston to force hydraulic fluid from said third chamber to said hydraulic actuator; said first and second chambers forming a fluid reservoir whereby, in the event that, for any reason, said third chamber, said tube and said hydraulic actuator are not completely filled with hydraulic fluid, when pressure is applied to said closed outer end of said bellows, hydraulic fluid initially is forced from said first chamber into said second chamber to move said piston away from said piston rod before said piston rod engages in said aperture, so that hydraulic fluid will flow from said second chamber through the aperture in the end wall of said piston into said third chamber to fill said third chamber, said tube and said actuator, whereupon further movement of said piston away from said piston rod is blocked and the inner end of said piston rod will sealingly seat in said aperture in the end wall of said piston to displace said piston to force hydraulic fuid from said third chamber through said tube to said hydraulic actuator.

2. Apparatus as claimed in claim 1, wherein said means forming a cylinder comprises a main body formed with a cylindrical bore communicating with said tube and receiving said piston and means clamping the open inner end of said bellows to said body; said diaphragm being a circular washer interposed between the open inner end of said bellows and said body; said washer being formed with a plurality of apertures therethrough, including a central aperture forming a guide for said piston rod; said washer providing for flow of hydraulic fluid between said first and second chambers.

3. Apparatus, as claimed in claim 2, in which said piston has a clearance in said cylindrical bore to provide for flow of hydraulic fluid between said second and third chambers.

4. Apparatus, as claimed in claim 1, including a depressable button engaged with the closed end of said bellows whereby to collapse said bellows responsive to pressure exerted on said button.

5. Apparatus, as claimed in claim 1, including spring means biasing said piston to engage the inner end of said piston rod.

6. Apparatus, as claimed in claim 1, in which said means forming a cylinder comprises a first body member formed with a cylindrical bore constituting said cylinder; a first coupling member securing an end of said tube in sealing relation to said first body member to communicate with said cylindrical bore; said actuator comprising a second body member formed with a hydraulic fluid chamber; and a second coupling member securing the opposite end of said tube to said second body member in sealing relation therewith and in communication with the hydraulic fluid chamber in said second body member.

7. Apparatus, as claimed in claim 6, in which the hydraulic fluid chamber in said second body member comprises an outwardly opening recess in said second body member; diaphragm means secured to said second body member and closing said recess; and a plunger engaged with said diaphragm means for movement therewith to transmit force to an object to be moved.

8. Apparatus, as claimed in claim 7, including spring means biasing said plunger to move said diaphragm means toward said chamber to force hydraulic fluid from said fluid pressure actuator into said first body member.

9. Apparatus, as claimed in claim 8, including a guide adjustably secured to said second body member and engaged with the outer end of said spring; said guide being constructed and arranged for connection to a part to be operated.