NZ204970A - Swivel type tube coupler - Google Patents

Description

2049 Priority Date(s): Complete Specification Filed: *?!?.. /?.l.6.437/eff.

Publication Date: .. .5.P! .

P.O. Journal, Nc: . W.h.

No.: Date: NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION TUBE COUPLING DEVICES J- f - & S. *3 l^9K©cln Ufarkf , Wrttoi*, 3|rw*i*afuiiM 156 7^, KtyWe, IMI NORGREN ENOTS LIMITED of Eastern ftvonu&, Liohfiolk, Jtaffordahire WS13 68C^ England, a British Company hereby declare the invention for which*#/ we pray that a patent may be granted to jgg|j/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) 2 049 7 0 -c»~ 70080 Tube Coupling Devices This invention concerns improvements in tube coupling devices, and more particularly so called "swivel" coupling devices which are intended to enable relative rotation ("swivelling") between the coupling 15 device and a member connected thereto whilst maintaining a fluid-tight seal between them.

Swivel coupling devices generally are known and typically comprise a male member rotatably and sealingly retained within a female member, the latter 20 usually being an integral part of a tube coupling body to which, in addition, one or more tubes may be connected. The male member usually has a screw thread for connection to a member to or from which fluid is to be led via the coupling device, for example a fluid 25 flow valve or a fixed fluid flow pipeline, but other types of connection are possible.

In one such known swivel coupling device, the male member comprises a tubular spigot portion received within the female member, there being an 30 elastomeric 0-ring or like sealing member between the external surface of the spigot portion and the internal surface of the female member. The female 204970 70080 member is provided at its outer end with a radially inwardly directed lip which extends into a circumferential groove formed in the external surface of the spigot portion of the male member, thereby 5 retaining the male member therein but allowing it to rotate relative thereto. Both the female and male members are made of metal, for example brass or zinc alloy. This arrangement has two disadvantages. Firstly, after a period of use, the lip tends to 10 become worn and this may ultimately lead to the male member becoming disengaged from the female member. Alternatively, galling followed by seizure could occur thus preventing swivelling. Secondly, the female member has to be specially formed to accept and retain 15 the male member. It would be advantageous if certain standard tube coupling devices could be readily adapted by stockists and users to swivel coupling devices. It is an object of the present invention to provide a swivel coupling that may be made by such 20 adaption and that also mitigates the problem of wear or seizure referred to above.

According to the present invention there is provided a tube coupling device of the swivel type including a hollow body member having a female 25 /§ terminal portion, n 1 nmji f iidi nn 1 j bored male member ' having an externally cylindrical spigot portion sealingly received within said female portion, and terminating in a connecting portion externally of the female portion, and retaining means retaining -the male 30 member in said female portion so that relative axial movement therebetween is substantially prevented but permitting of relative rotation between the male member and the hollow body member about the 2 04 9 3 70080 longitudinal axis of the male member, wherein said retaining means comprises a plastics bush retained, substantially against axial movement, within the female portion of the body member, the bush having a 5 circular cylindrical bore extending therethrough with integral plastics detent means extending towards the axis of the bore and wherein the spigot portion of the male member is received within the bore of the bush and has a circumferential recess formed therein into 10 which the detent means extends so as normally to prevent withdrawal of the male member from the body member.

The coupling device may be of any desired form such as a straight, elbow or T and the body will have 15 a corresponding configuration as appropriate.

Usually, in the case of a straight coupling, for example, the female portion will constitute one end portion of the body for swivel connection, via the male member, to some other item and the opposed end of 20 the body will be provided with means for connection to a tube. Such connection may be of any desired type for example a compression connection or a so-called "push in" connection. However, it is within the scope of this invention for any one coupling device to have 25 two or more swivel connections. The body may be made of a suitable metal,such as brass, or a suitable plastics material, and may, for example, instead of being the body of a discrete tube-to-tube coupling device, be part of apparatus, such as a valve body, in 30 which the bush and male member are retained.

The bush may be fixedly secured in the female portion of the body in any desired way. However, where, as preferred, a swivel coupling device of the invention has been assembled using, inter alia, a 20497 0 70080 conventional, non-swivel body, the mode of retention of the bush will to a large extent be dictated by the nature of the interior form of that body. For example, in the case of a straight coupling body that 5 would normally be used, in conjunction with suitable collets and 0-rings, to connect two tubes by a "push-in" connection, the bush is suitably designed and retained in the body in a manner analogous to that in which the collet is retained. Such an embodiment 10 is described later with reference to the accompanying drawings. On the other hand where, for example, the body is internally threaded and would normally be used to connect tubes by means of a compression fit, the bush may be retained in the body by means of 15 screw-threaded engagement therewith. It can therefore be seen that one and the same body may be used either in a conventional non-swivel coupling device or, by selecting a suitable bush and male member, in a swivel coupling device of the invention. This has obvious 20 advantages for stockists and users in that one and the same body may be readily adapted to alternative forms.

The bush is in the form of a one piece plastics moulding, preferably of an acetal polymer. In preferred embodiments, the bush is fixedly secured 25 within the female portion of the body member against both axial and rotational movement relative to the body member, the cylindrical wall of the bore extending through the bush providing a non-lubricated bearing surface rotatably supporting the spigot 30 portion of the male member which may be of a metal such as brass. However, in addition or alternatively in certain cases, the bush may be rotatable relative to the body member. In either case, during swivelling 2 049 70080 of the coupling device, any wear will be insignificant and furthermore there is little likelihood of seizure occurring between relatively rotating parts.

The connecting portion of the male member 5 externally of the female portion may provide for any type of connection. Usually, however, it will comprise an external screw thread in which case a portion of the male member externally of the female portion is preferably provided with a number of flats 10 for engagement by a spanner.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings of which:- Figure 1 is a sectional side elevation of a 15 swivel coupling device of the invention shown as connecting a flexible fluid flow tube to a valve block; and Figure 2 is a sectional side elevation, on an enlarged scale, of the bush that forms 20 part of the coupling device shown in Figure 1.

Referring to Figure 1, the coupling device includes a hollow brass body 1 in the form of a 90° elbow and comprising two identical bored and undercut 25 female portions 2 and 3 interconnected by a bore 4.

The portions 2 and 3 are formed internally with, inter alia, conical surfaces 5 and 5" respectively. Referring to portion 2, this houses an elastomeric O-ring seal 6 and a tube-gripping collet 7 of brass 30 which respectively serve to form a fluid-tight seal with, and retain within the body 1, a plastics tube V * J .a 204970 70080 8. The plastics tube 8 is connected to the coupling device merely by pushing it into the device until it reaches the tube stop 9 formed in the body 1. The operation of such "push-in" fittings is known to those 5 skilled in the tube-coupling art and is described in, for example, British Patent No 1 270 648. Briefly, the collet 7 comprises a plurality of flexible arms lOeach provided with a tooth 11 which lightly grips the tube 8. If an attempt is made to withdraw the 10 tube without first depressing the collet 7, the collet moves axially outwards with the tube and co-acts with the conical surface 5 thereby increasing its grip on the tube thus preventing withdrawal of the tube. However, if the collet 7 is depressed axially inwardly 15 whilst withdrawing the tube 8, the tube can readily be withdrawn form the coupling.

Referring to the portion 3, this also houses an elastomeric 0-ring 6' but, instead of the tube gripping collet 7, it fixedly retains a plastics bush 20 12 moulded from an acetal or other suitable polymer which in turn retains and rotatably supports an axially bored brass male member 13.

Referring also to Figure 2, the bush 12 comprises an outer annular support portion 14, having 25 an internal, cylindrical surface 15, from which there axially extend a plurality of (for example four) spaced flexible arms 16. As in the case of the collet 7, the arms 16 of the bush 12 are sufficiently spaced that the bush 12 may be located in the portion 3 30 simply -by pushing it thereinto by hand whereupon the arms 16 first contract radially as they pass along the converging conical surface 17 formed in portion 3 and then expand radially, upon further insertion of the V *• 204970 70080 bush, as they pass along the diverging conical surface '. The final assembled position of the bush 12 is as J shown in Figure 1. The bush 12 is formed with an integral, radially outwardly extending, flexible 5 flange 18 which abuts a shoulder 19 formed in the female portion 3 and serves to take up any "rattle". The innermost end of each flexible arm 16 comprises two portions, namely a radially outer portion 20 which engages the conical surface 5' and a radially inner 10 portion 21 from which there projects, generally inwardly towards the axis of the bush 12, a resilient detent lip 22 having a planar and face 22'.

The axially bored brass male member 13 comprises a spigot portion 23, a central portion 24 15 having a diameter greater than the spigot portion 23 and formed externally with a number of spanner flats 25, and an externally screw threaded portion 26. The spigot portion 23 has a circumferential channel 27 of rectangular section formed therein which provides an 20 annular abutment surface 28 extending normally to the axis of the member 13.

The member 13 is assembled into the coupling simply by pushing it into the bush 12 whereupon the forward end of the spigot portion 23 passes through, 25 and sealingly engages, the 0-ring 61 and each lip 22 eventually snaps into the channel 27, the end face 22' of which lip abuts the surface 28 thereby permanently retaining the male member 13 in the coupling. The internal surface 15 of the portion 14 of the bush, and 30 to some extent the internal surface of each arm 16, provide a non-lubricated bearing surface for the spigot portion 23 of the male member 13 whereby the body 1 of the coupling device may readily rotate 2 04 970 8 M70080 relative thereto. In Figure 1, the male member 13 is shown to be screw-threadedly engaged in a tapped port of a valve body 29.

Because the brass male member 13 is 5 substantially solely located, and rotatably supported, by the plastics bush 12, wear of the relatively , rotating components will be minimal. Although, as will be seen from Figure 1, there will be metal to metal "rotating contact between the inner end of the 10 spigot portion 23 and the body 1, any wear that occurs here is of little consequence and, in any case, will be minimal because the contacting surfaces will be lubricated by fluid passing through the coupling during use. Further, as will be appreciated, the body 15 1 could be used either in the manner shown in Figure 1, or the portion 3 could alternatively be provided with a collet such as 7 so as to provide an elbow coupling for connecting together two tubes in a push-in mode. In either event, the collet or bush and 20 male member, as the case may be, can readily be assembled into the body 1 by a stockist or user without using tools.

Claims (6)

2049 9 70080 WHAT^WE CLAIM IS;

1. A tube coupling device of the swivel type including a hollow body member having a female terminal portion, a fcudTiialy bored male member having an externally cylindrical spigot portion 5 sealingly received within said female portion, and terminating in a connecting portion externally of the female portion, and retaining means retaining the male member' in said female portion so that relative axial movement therebetween is substantially prevented but 10 permitting of relative rotation between the male member and the hollow body member about the longitudinal axis of the male member, wherein said retaining means comprises a plastics bush retained, substantially against axial movement, within the 15 female portion of the body member, the bush having a circular cylindrical bore extending therethrough with integral plastics detent means extending towards the axis of the bore and wherein the spigot portion of the male member is received within the bore of the bush 20 and has a circumferential recess formed therein into which the detent means extends so as normally to prevent withdrawal of the male member from the body member.

2. A tube coupling device as claimed in Claim 1 25 wherein the bush is fixedly secured within the female portion against both axial and rotational movement relative to the body member and wherein the male member can rotate, within the bore of the bush, about its longitudinal axis. 30

3. A tube coupling device as claimed in Claim 1 or Claim 2 wherein the female portion of the body 20497 0 10 70080 member has an internal frusto-conical surface that converges towards the outer end of the female portion of the body member and an internal cylindrical surface intermediate said frusto-conical surface'and said 5 outer end, and wherein the bush comprises an annular portion located within and by said cylindrical surface, said annular portion having integral therewith a plurality of spaced, generally axially extending, radially flexible arms each having an 10 enlarged portion at the end thereof remote from the annular portion, each said enlarged portion being wedged between said internal frusto-conical surface of the female portion and the outer surface of the spigot portion of the male member and having an 15 integral detent lip extending generally towards the axis of the bush and into said circumferential recess formed in the spigot portion of the male member.

4. A tube coupling device as claimed in Claim 3 wherein the bush is formed, adjacent to said annular 20 portion, with an integral, resilient flange that abuts a shoulder formed internally of the female portion of the body member, said flange serving to prevent axial rattle of the bush relative to the body member.

5. A tube coupling device as claimed in any o/j 25 of Claims 1 to 4 wherein the recess in the spigot portion of the male member defines, in part, an annular surface extending substantially normally to" the longitudinal axis of the male member and facing the open end of the female member and wherein the 30 detent means has a planar surface extending parallel to, and abutting, said annular surface.

6. A swivel tube coupling device substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2 of the accompanying draWln9S- DATED THIS Ji^DAY OF 19 S3 A. J. PARK & SON PER C<1^ AGENTS FOR THE APPLICANTS 35