Venting Valve For Hydraulic Jack

Abstract

A filler plug and venting valve assembly to regulate the pressure in the liquid reservoirs of hydraulic jacks comprises a housing that is mounted on the jack to open into the reservoir. It contains a flexible valve sleeve that responds to the difference in pressure between the reservoir and atmosphere to permit air to be drawn into the reservoir when oil is taken from the reservoir and air to be vented from the reservoir when oil is returned to the reservoir and also flexes to permit oil to be added to the reservoir through the valve.

Description

BRIEF SUMMARY OF THE INVENTION

It is the purpose of the invention to provide a combined filler plug and venting valve for use in conjunction with the liquid reservoir of an hydraulic jack or the like that is constructed in such a way that it will regulate airflow to and from the reservoir, and will permit filling of the reservoir but will also seal it to prevent leakage during shipment of the jack or during unusual handling of the jack.

The invention accomplishes this by means of a valve device which includes a housing containing a flexible sleeve valve that responds to pressure differentials between the atmosphere and the oil reservoir and will deflect to permit oil to flow through the valve mechanism and enter the reservoir. The wall thicknesses of different portions of the flexible sleeve are controlled to provide a means for determining the maximum and minimum pressures in the reservoir.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automotive type service jack having a hydraulic operating mechanism which includes the valve assembly of this invention;

FIG. 2 is a sectional view on an enlarged scale showing a portion of the hydraulic mechanism for the jack in FIG. 1 including the valve assembly of this invention;

FIG. 3 is an enlarged cross section through the valve assembly of this invention;

FIG. 4 is an enlarged cross section similar to FIG. 3 but showing the flexible valve element in a position that permits the intake of air; and

FIG. 5 is a view similar to FIGS. 3 and 4 showing the flexible valve in a position to permit the expulsion of air.

DETAILED DESCRIPTION OF THE INVENTION

The service jack 1 of FIG. 1 has a hydraulic-type operating mechanism 3 which is described in detail in U.S. Pat. No. 2,447,650. The jack 1 and the mechanism 3 are disclosed as typical environments for the valve assembly of this invention and it will be apparent that the valve assembly can be used with the hydraulic liquid reservoirs of other specific hydraulic mechanisms.

The hydraulic mechanism 3 includes a base 5 that contains a pump chamber in which a pump piston 7 reciprocates as the handle 8 is pumped up and down by an operator. The pressure generated by the pump 7 causes flow of hydraulic oil through suitable valved passages 9 to the pressure side of a ram chamber 11 so as to force the ram 13 upwardly or to the right in FIG. 2. The oil which is moved by pump 7 is stored in an annular oil reservoir 15 that is provided between the walls of the ram cylinder 17 and the reservoir cylinder 19. A release valve 21 may be manually operated so that when it is seated movement of the pump 7 will apply pressure to the ram 13 and when it is unseated pressure on the pressure face of the ram 13 will be relieved so that the jack is lowered and the system is at reservoir pressure. During operation of the pump 7 oil is removed from reservoir 15 and forced into cylinder 11 and the reverse flow occurs when the pressure is released.

In accordance with this invention, a valve assembly 23 is threaded into the filler hole 24 for the reservoir 15. The assembly 23 includes a nipple 25 to receive a hydraulic line or connection whereby hydraulic oil may be fed into the reservoir 15 through the valve assembly 23. In addition, as will be described, the valve assembly 23 includes a flexible valve sleeve that not only permits filling, as just mentioned, but automatically deflects to permit air to be drawn through the nipple 25 as oil is removed from reservoir 15 and expelled from the reservoir as oil is returned to the reservoir during operation of the mechanism 3.

As seen in FIG. 3, the valve assembly 23 comprises a tubular valve housing or body 27 which includes a valve retainer member 29 that provides the nipple 25 at its outer end. The nipple 25 includes a central passage 31 in retainer 29 that terminates in the cross passage 33 opening out of opposite sides of a reduced diameter section 35 of the retainer 29. The valve body 27 has an annular shoulder 37 on which is seated the enlarged flange 39 of a rubberlike flexible tubular valve member 41. The retainer 29 has a press fit in the body 27 and holds the flange compressed against seat 37 to produce a fluidtight seal.

Extending away from the flange 39 the valve member 41 has a lengthy sleeve section 43 with a portion 43a of a thicker wall section and a portion 43b of a thinner wall section. The thicker portion 43a preferably coincides in length with the retainer portion 35 and the inner diameter 44 of the valve 41 fits snugly on the reduced diameter section 35 of the retainer 29. The valve sleeve 43 passes through a valve chamber 45 in the body 27 which is substantially larger in diameter than the section 43 to give the portion 43a room to expand or flex outwardly and uncover the opposite ends of the cross opening 33 (FIG. 5). The terminal end of the portion 43b fits snugly in and is supported on a reduced diameter section 47 of the valve body 27. This portion of the valve body is exteriorly threaded at 49 so that the valve assembly 23 can be screwed into the filler plug hole 24. Atmospheric air pressure reaches chamber 45 on the outside of sleeve section 43 by way of transverse aperture 51 which contains a filter 53.

Referring to FIG. 4, during operation when oil is being drawn from the reservoir 15, pressure in the reservoir drops below atmospheric. As a result, the pressure in chamber 45 on the outside of sleeve portion 43b is higher than that inside the sleeve and the sleeve deflects or collapses off the diameter 47. Air can then pass from passage 51 through the chamber 45 and diameter 47 to reach the reservoir 15 and reduce the vacuum in it. By controlling the wall thickness of the rubber in portion 43b the pressure differential required to cause it to leave seat 47 can be controlled, thereby controlling the maximum vacuum (minimum pressure) in the reservoir 15.

Referring to FIG. 5, during operation when oil is being returned to the reservoir, pressure is built up producing a seal of portion 43b on surface 47 and expanding portion 43a to connect inner diameter 44 with the ends of cross passage 33. Air from the reservoir 15 is therefore expelled to atmosphere through passage 31 and the maximum pressure that the reservoir will hold is controlled by the fit or squeeze of bore 44 on diameter 35 and the wall thickness of valve portion 43a.

It will therefore be seen that by adjusting the wall thicknesses 43a and 43b in accordance with the limits determined by functioning of the jack 1 and by the atmospheric conditions where the jack is used, the maximum and minimum pressures in reservoir 15 can be controlled as desired.

It is apparent that the reservoir 15 can be filled with oil simply by attaching a hose or other suitable connection to nipple 25, the pressure of the oil deflecting the section 43a, as in FIG. 5, to enable the oil to reach the reservoir. Conversely, the valve is normally in the static position of FIG. 3 where it will prevent leakage or escape of oil during shipment of the jack, eliminating the need for a special seal, and in the event of unusual handling of the jack.

Claims

I claim:

1. In a hydraulic pumping mechanism having a housing providing a reservoir for hydraulic liquid, a venting valve mounted on the housing in communication with the reservoir, said valve having a body with first and second passages opening to atmosphere, the first passage forming means for the infeed of hydraulic liquid and the outflow of air under pressure in the reservoir, the second passage forming means for the inflow of air to relieve vacuum in the reservoir, and flexible valve means closing the first and second passages and operated by high pressure in the reservoir to open the first passage and connect it to the reservoir and to close the second passage and operated by vacuum in the reservoir to open the second passage and connect it to the reservoir and to close the first passage.

2. A valve as set forth in claim 1 wherein said valve means comprises a resilient rubberlike sleeve having an inner periphery closing the first passage and an outer periphery closing the second passage, the inside of said sleeve communicating at all times with said reservoir.

3. A valve as set forth in claim 2 wherein the portion of the sleeve closing the first passage has a greater resistance to deflection than the portion of the sleeve closing the second passage.

4. A valve as set forth in claim 1 wherein said valve means comprises a resilient rubberlike sleeve having longitudinally adjacent wall sections, the first of said wall sections being thicker than the second and having an inner periphery closing the first passage, the outer periphery of the second wall section closing the second passage, the inside of said sleeve communicating at all times with said reservoir.

5. A valve as set forth in claim 4 wherein said body has a chamber containing said sleeve, said chamber having an end portion engaged by the second wall section of the sleeve, said second passage opening into said chamber on the outside of the sleeve, said body having a projection in said chamber containing said first passage and fitting inside the first wall section of the sleeve.

6. In an hydraulic pumping mechanism having a housing providing a reservoir for hydraulic liquid, a venting valve device mounted on the housing to communicate with the reservoir, said valve including a valve body, a rubberlike valve element mounted in the body having two portions of different resiliency, and a pair of gas passages in the body for connecting the reservoir to atmosphere, said passages being sealed by said valve element, one of said valve portions sealing one of the passages against inflow of air but flexing to provide venting, the other of said valve portions sealing the other of the passages against outflow but flexing to provide for inflow of air.

7. A device as set forth in claim 6 including means associated with the first one of said passages for receiving hydraulic liquid to be fed to the reservoir, the first one of said valve element portions flexing to provide for hydraulic liquid flow through the body into the reservoir.

8. A venting valve for attachment to a hydraulic pumping mechanism, said mechanism having a housing providing a reservoir and a filler hole for the reservoir, said venting valve including a valve body having an end portion adapted to be mounted in said filler hole whereby said valve is attached to said mechanism, said valve body including an internal chamber having a reduced diameter end section for opening into the filler hole, said valve body including a reduced diameter projection extending into the chamber at the end opposite said end section, said projection having a transverse passage adjacent its inner end opening into said chamber, said body having passage means providing a passage connecting the transverse passage to the outside of the valve, said body having an opening therein connecting the chamber to the outside of the valve, a rubberlike transversely resilient valve sleeve element sealingly secured to one end in the body and having a first annular wall portion with an inner surface fitting tightly around the projection to provide a resilient closure for the transverse passage, said sleeve element having a second annular wall portion with an outer surface fitting on the surface of said end section to provide a resilient closure for the end section and chamber, said first and second wall portions being of selected thicknesses so that the first wall portion unseats from the cross passage at a relatively high pressure on the inside of the sleeve element and the second wall portion unseats from the end section at a predetermined pressure less than atmospheric inside of the sleeve element.

9. A valve as set forth in claim 8 wherein said passage means includes a nipple for connection to a source of liquid for filling the reservoir.