GB2172357A

GB2172357A - Pipe coupling

Info

Publication number: GB2172357A
Application number: GB08506710A
Authority: GB
Inventors: Stanley Terence O'flynn
Original assignee: General Motors Overseas Commercial Vehicle Corp
Current assignee: General Motors Overseas Commercial Vehicle Corp
Priority date: 1985-03-15
Filing date: 1985-03-15
Publication date: 1986-09-17
Also published as: GB2172357B; GB8506710D0

Abstract

A pipe coupling (1) for connecting a pipe (14) to a fluid housing (20) in which a radiused seat (11) on the bolt head (4) may be provided to engage a conical seat (15) on a connector body (3), and a radiused seat (18) on the connector body may be provided to engage a conical seat (23) on the fluid housing, thereby forming a continuous line of contact between the bolt head and the connector body, and between the connector body and the fluid housing. Alternatively the continuous line of contact may be formed by a circular ridge of semi-circular cross-section on one surface engaging a flat face on the co-operating surface. <IMAGE>

Description

SPECIFICATION Pipe coupling This invention relates to a pipe coupling for connecting a pipe to a fluid (gas or liquid) housing, for example, a storage tank, internal combustion engine, heating radiator, fluid pump housing, etc. In particular, this invention relates to a pipe coupling in which the longitudinal axis of the pipe is at an angle to the longitudinal axis of the coupling.

A known pipe coupling of this type is commonly referred to as a "banjo" connector. Known banjo connectors comprises a bolt for screw threading to an aperture in a fluid housing and having a central passageway, a connector body having a passageway through which the bolt shank can pass and which is connected to a pipe, and two fluid sealing washers, one positioned between the bolt head and the connector body, the other positioned between the connector body and the fluid housing.

These banjo connectors have been known for many years. They have the disadvantage that when the bolt is screwed tightly to the fluid housing, the load (pressure) is spread over the whole of the surfaces of each washer. Consequently, leakage of fluid often occurs from these pipe couplings, and in an effort to prevent leakage, the bolt is often overtightened thereby causing thread damage.

It is an object of this invention to overcome this disadvantage.

In accordance with the present invention a pipe coupling for connecting a pipe to a threaded aperture in a fluid housing, comprises (a) a bolt comprising a bolt shank having a bolt head at one end, the shank having a threaded outer surface for screw threading to the threaded aperture in the fluid housing, the threaded outer surface extending from the other end of the shank along part of its length, and a passageway extending from the other end of the shank along the longitudinal axis of the shank, the passageway being open at the other end of the shank and being connected by at least one aperture to the outer surface of the shank adjacent the bolt head; and (b) a connector body having a through passageway through which the bolt shank extends and a pipe passageway for connection to a pipe and connected to the through passageway such that the longitudinal axis of the pipe passageway is at an angle to the longitudinal axis of the bolt shank; characterised in that the bolt head directly engages the connector body and the connector body directly engages the fluid housing, the engaging surfaces being so shaped as to form a continuous line of contact between the bolt head and the connector body and between the connector body and the fluid housing.

As a continuous line of contact is formed between the engaging surfaces, the load generated by screwing the bolt tightly to the fluid housing is concentrated on the lines of contact, and is therefore of substantially infinite value. The risk of fluid leakage is therefore substantially reduced. Further, as washers are not required, the number of components forming the pipe coupling is reduced.

Preferably the bolt head has a radiused seat for engaging a corresponding conical seat in the connector body, or vice versa; and the connector body has a radiused seat for engaging a corresponding conical seat in the fluid housing, or vice versa; the engagement of the radiused seats with their corresponding conical seats forming the continuous line of contact between the bolt head and the connector body, and between the connector body and the fluid housing.

As the bolt and connector body are usually manufactured by a turning process, the inclusion of radiused or conical seats can be achieved with little increase in manufacturing costs.

Where the bolt head has a radiused seat and the connector body has a corresponding conical seat, preferably the radiused seat is positioned on the bolt head adjacent the bolt shank, and the conical seat is defined by a tapered surface at the opening to the through passageway in the connector body adjacent the bolt head. Where the connector body has a radiused seat and the fluid housing has a corresponding conical seat, preferably the radiused seat is positioned adjacent the opening to the through passageway adjacent the fluid housing, and the conical seat is defined by a tapered surface at the opening to the threaded aperture in the fluid housing.

Alternatively, each continuous line of contact may be defined by a substantially circular ridge of substantially semi-circular cross-section on one surface engaging a flat face on the corresponding surface.

Preferably the longitudinal axis of the pipe passageway is at right angles to the longitudinal axis of the bolt shank.

The connector body may be connected to the pipe by any suitable method, for example by welding or by screw fixing.

Preferably the bolt and connector body are made of hard metal, for example, steel. This arrangement provides a better leak proof coupling, and readily allows the coupling to be re-used.

This invention is now described by way of example with reference to the accompanying drawing which is a cross-sectional view of a pipe coupling in accordance with the invention.

Referring to the drawing, the pipe coupling 1 comprises a bolt 2 and a connector body 3. The bolt 2 comprises a bolt head 4 connected to one end of a shank 5. The shank 5 has a threaded outer surface 6 extending from the other end 7 of the shank along part of the length of the shank. The shank 5 also has a passageway 8 extending from the other end 7 of the shank along the longitudinal axis A of the shank. The passageway 8 is open at the other end 7 of the shank and is connected by four apertures 9 to the outer surface 10 of the shank adjacent the bolt head 4. The bolt head 4 has a continuous radiused seat 11 formed at the junction of the bolt head and the bolt shank 5.

The connector body 3 comprises a through passageway 12 through which the bolt shank 5 can pass and which is connected to a pipe passageway 13. The longitudinal axis B of the pipe passageway 13 is at right angles to the longitudinal axis A of the bolt shank. A pipe 14 is fixed in the pipe passageway 13. The connector body 3 has a conical seat 15 defined by a tapered surface 16 at the opening of the through passageway 12 on the side 17 of the connector body adjacent the bolt head 4, and a radiused seat 18 adjacent the opening of the through passageway on the other side 19 of the connector body.

In use, the bolt 2 is threaded in a threaded aperture 21 in a fluid housing 20. The opening of the threaded aperture 21 has a tapered surface 22 which defines a conical seat 23 in the fluid housing 20. When the bolt 2 is securely fastened to the fluid housing 20, radiused seat 11 engages conical seat 15 to form a continuous line of contact between the bolt head 4 and the connector body 3, and radiused seat 18 engages conical seat 23 to form a continuous line of contact between the connector body 3 and the fluid housing 20. Because of the continuous lines of contact the load applied at the engaging surfaces is substantially infinite, and the risk of fluid leakage is substantially reduced.

Claims

1. A pipe coupling for connecting a pipe to a threaded aperture in a fluid housing, the pipe coupling comprising (a) a bolt comprising a bolt shank having a bolt head at one end, the shank having a threaded outer surface for screw threading to the threaded aperture in the fluid housing, the threaded outer surface extending from the other end of the shank along part of its length, and a passageway extending from the other end of the shank along the longitudinal axis of the shank, the passageway being open at the other end of the shank and being connected by at least one aperture to the outer surface of the shank adjacent the bolt head; and (b) a connector body having a through passageway through which the bolt shank extends and a pipe passageway for connection to a pipe and connected to the through passageway such that the longitudinal axis of the pipe passageway is at an angle to the longitudinal axis of the bolt shank; characterised in that the bolt head directly engages the connector body and the connector body directly engages the fluid housing, the engaging surfaces being so shaped as to form a continuous line of contact between the bolt head and the connector body and between the connector body and the fluid housing.

2. A pipe coupling as claimed in Claim 1, wherein the bolt head has a radiused seat for engaging a corresponding conical seat in the connector body, or vice versa; and the connector body, has a radiused seat for engaging a corresponding conical seat in the fluid housing, or vice versa; the engagement of the radiused seats with their corresponding conical seats forming the continuous line of contact between the bolt head and the connector body, and between the connector body and the fluid housing.

3. A pipe coupling as claimed in Claim 2 in which the bolt head has a radiused seat and the connector body has a corresponding conical seat, wherein the radiused seat is positioned on the bolt head where the bolt head is connected to the bolt shank, and the conical seat is defined by a tapered surface at the opening to the through passageway in the connector body adjacent the bolt head.

4. A pipe coupling as claimed in Claim 2 or Claim 3 in which the connector body has a radiused seat and the fluid housing has a corresponding conical seat, wherein the radiused seat is positioned adjacent the opening of the through passage adjacent the fluid housing, and the conical seat is defined by a tapered surface at the opening to the threaded aperture in the fluid housing.

5. A pipe coupling as claimed in Claim 1, wherein each continuous line of contact is defined by a substantially circular ridge of substantially semi-circular cross-section on one surface engaging a flat face on the corresponding surface.

6. A pipe coupling as claimed in any one of the preceding claims, wherein the longitudinal axis of the pipe passageway is at right angles to the longitudinal axis of the bolt shank.

7. A pipe coupling substantially as hereinbefore defined with reference to, and as shown in, the accompanying drawing.