GB2044402A

GB2044402A - Air bleeder

Info

Publication number: GB2044402A
Application number: GB8005400A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1979-02-22
Filing date: 1980-02-18
Publication date: 1980-10-15
Also published as: JPS55122575U; SE8001329L

Abstract

A base portion 42 of a cap made of a resilient material for an air bleeder has a substantially larger area than the cross-sectional area of a hole 32 provided in an outer surface of a device body containing hydraulic oil. The base portion of the cap is fitted over the body of an air bleeder between an outer driven portion 18 thereof and the outer surface of the device body and is sealingly pressed against the outer surface of the device body so that any clearance between the hole in the outer surface of the device body and an outer screwed portion of the bleeder body screwed therein is completely covered by the base portion of the cap in a watertight manner. <IMAGE>

Description

SPECIFICATION Air bleeder The present invention relates to an air bleeder suitable for use with hydraulic devices.

Conventionally, oil hydraulic brakes and cylinders used with automotive vehicles and industrial machines are provided with an air bleeder for bleeding air confined within the cylinders and brakes. That is, as shown in Fig. 1 of the accompanying drawings, an air bleeder 10 is fixed to a device 30 containing hydraulic oil, not shown, so that a threaded stem 1 2 of the bleeder body 1 3 is screwed into a threaded hole 32 provided in an outer surface 34 of the body 36 of the device 30, which hole communicates with an air-bleeding passage 38 provided in the body of the device. The head portion 41 of a cap 40 of a resilient material such as rubber is fitted over the head 14 of the bleeder body so as to protect the passage 38 from being clogged with dust and so on.The cap is attached at its base portion 42 to a portion 1 6 of the bleeder head 14 in order to prevent it from falling off. The bleeder body is provided with hexagonal nut 18 formed integrally with the head 14 by which the bleeder is driven in order to be screwed into or out of the threaded hole 32 in the outer surface 34 of the device body 34. Normally, the passage 38 is closed by an end 20 of the bleeder pressing on a conical surface 32a of the hole 32. Loosening of the bleeder and removal of the cap opens the passage 38 to the atmosphere through a small hole 22 provided in the side surface of the bleeder and an axial passage 24 formed in the bleeder and communicating with the small hole 22, and open at the top of the head of the bleeder to the atmosphere.

With such a bleeder, dirty water and other contaminants are liable to enter the passage 38 in the device body 36 through the clearance between the outer threaded stem 12 of the bleeder body 13 and the inside surface of the hole 32. Thus the bleeder rusts at its stem 12 and becomes difficult to loosen to bleed air from the device. Excessive loosening causes the bleeder, which has a hollow structure, to be broken, which brings about losses such as a leakage of hydraulic oil or possibly replacement of the whole device.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide an air bleeder for use with a device containing hydraulic fluid, which bleeder prevents water from entering any clearance formed between the outer threaded stem of the bleeder and an inner threaded hole in the body of the device containing hydraulic fluid.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the present invention will be apparent from the description taken with reference to the accompanying drawings, In the drawings: Fig. 1 is a partially sectionai view of a prior art air bleeder screwed in a body containing hydraulic fluid; Fig. 2 is a view similar to Fig. 1 of a preferred embodiment of the air bleeder according to thepresent invention; Fig. 3 is a view similar to Fig. 1 of a modification of the air bleeder according to the present invention; Fig. 4 is a view similar to Fig. 1 of a further modification of the air bleeder according to the present invention; and Fig. 5 is a view similar to Fig. 1 of a still further modification of the air bleeder according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The same reference numerals denote similar or corresponding parts or portions throughout the drawings. Thus the same or similar descriptions will not be repeated, for the purpose of simplification.

In a preferred embodiment, shown in Fig.2, of an air bleeder according to the present invention, a base portion 42 of a cap 40 is fitted over a body 13 of the bleeder between an outer-polygonal driven portion such as a nut 18 and an outer surface 34 of the device body 36, and pressed watertightly against the outer surface 34 by the nut 18 so as to seal a threaded stem 12 of the bleeder body 13 from outside and thus to prevent the entry of water into the clearance between the threaded stem 12 of the bleeder and the hole 32 and therefore the formation of rust on the outer surface of the stem 12 of the bleeder.In this case, the outer diameter of the nut 1 8 and the base portion 42 of the cap 40 each have an area large enough to cover the hole 32; the outer diameter of the base portion of the cap and the diameter of the driven portion of the bleeder body should preferably be each at least 1.5 times the diameter of the hole in the surface of the device body.

In a modification, shown in Fig. 3, of the present invention, the base portion 42 of the cap 40 is provided with an inner annular groove 42a which is filled with grease 44. This bleeder acts to prevent the generation of rust more effectively than the bleeder of Fig. 2 as well as to facilitate the loosening of the air bleeder. Of course this improvement can be incorporated equivalently by forming a corresponding annular groove in the bleeder body.

In a further modification, shown in Fig. 4, of the present invention, both the nut 1 8 and the base portion 42 of the cap 40 are substantially increased in area compared with those of Figs. 2 and 3.

In a still further modification, shown in Fig. 5, of the present invention, a washer 50 is placed between the nut 1 8 and the base portion 42 of the cap 40. The washer 50 and the base portion 42 of - the cap have a substantially iarger diameter than the inner diameter of the hole 32; the outer diameter of the washer and the outer diameter of the base portion of the cap should preferably be each at least 1.5 times the diameter of the hole in the surface of the device body.

The bleeders of Figs. 4 and 5 more effectively prevent the entry of water into the clearance between the stem 12 of the bleeder body 13 and the hole 32 in the device body 36 than the bleeder of Fig. 2. The base portions 42 of the caps 40 shown in Figs. 4 and 5 may be provided with an inner annular groove filled with grease as shown by 42a in Fig. 3 which serves even more effectively to prevent the formation of rust on the stem of the bleeder body, as described above.

As an example of such modification, it will be clear that the driven portion of the bleeder body which in the particular embodiments illustrated is a hexagonal nut, is not restricted to such a shape at all, but may be of any design, whether polygonal or not, which allows the bleeder to be screwed in and out.

Although the present invention has been shown and described with reference to one preferred embodiment and several modifications thereof, it should not be considered as limited to these, however, or mere and simple generalizations thereof, or other detailed embodiments. Yet further modifications to the form and the content of the particular embodiment and modifications may be made, without departing from the scope of the present invention, which it is therefore desired should be defined not by any of the purely fortuitous details of the shown embodiment and modifications, or of the drawings, but solely by the

Claims

appended claims. CLAIMS

1. An air bleeder for use with a device containing hydraulic fluid, comprising: a bleeder body including a head, threaded stem adapted to be screwed into a hole provided in a surface of the device containing hydraulic fluid, and an outer driven portion located between the head and the stem, the body having an internal passage extending substantially axially therethrough; and a cap of resilient material, having a head portion disposed over the head of the bleeder body and a base portion fitted over the bleeder body between the driven portion and the threaded stem, the base portion having a diameter sufficiently large to cover the hole into which the bleeder is screwed, and adapted to seal the gap between the driven portion and the surface of the device into which the bleeder is screwed.

2. The air bleeder claimed in claim 1 in which the outer diameter of the base portion of the cap and the diameter of the driven portion of the bleeder body are each substantially larger than the diameter of the threaded stem of the bleeder body.

3. The air bleeder claimed in claim 1 in which the outer diameter of the base portion of the cap and the diameter of the driven portion of the bleeder body are each at least 1.5 times the diameter of the hole in the surface of the device.

4. The air bleeder claimed in claim 1 further comprising a washer disposed between the driver portion of the bleeder body and the base portion of the cap.

5. The air bleeder claimed in claim 4 in which the outer diameter of the washer and the outer diameter of the base portion of the cap are each substantially larger than the diameter of the threaded stem of the bleeder body.

6. The air bleeder claimed in claim 4 in which the outer diameter of the washer and the outer diameter of the base portion of the cap are each at least 1.5 times the diameter of the hole in the surface of the device.

7. The air bleeder as claimed in any of claims 1 to 6 in which an annular groove, adapted to be filled with grease, is formed in the base portion of the cap in the surface in contact with the bleeder body.

8. The air bleeder as claimed in any of claims 1 to 6 in which an annular groove, adapted to be filled with grease, is formed in the surface of the bleeder body in contact with the base portion of the cap.