GB2158909A

GB2158909A - Clamped swivel fluid-coupling

Info

Publication number: GB2158909A
Application number: GB08512653A
Authority: GB
Inventors: Mathias Konrad
Original assignee: GKN Walterscheid GmbH
Current assignee: Walterscheid GmbH
Priority date: 1984-05-18
Filing date: 1985-05-20
Publication date: 1985-11-20
Also published as: DE3418559A1; IT8505142A0; FR2564562A1; FR2564562B1; GB2158909B; IT1186285B; DE3418559C2; JPS60245896A; IT8505142A1; IT8506955V0; GB8512653D0

Abstract

A coupling comprising a bolt 1 having a hollow shank forming a first conduit 7 and radially disposed, axially spaced and equiangularly spaced bores 6 each of the same diameter as the first conduit 7. An annular housing 2 having an annular recess defines with the bolt an annular cavity 4, and the housing 2 has a second radial conduit 11. Seals 3 maintain fluid tightness when the bolt is tightened to a piece of apparatus 10 securing the housing from pivotal movement. The bores 6 are spaced axially by less than one bore diameter but such that at any transverse cross-section at a region pierced by one or more bores the width of the bore of sum of the widths of the bore at that section is substantially equal to or less than one bore diameter. <IMAGE>

Description

SPECIFICATION Adjustable fluid-coupling The invention relates to an adjustable fluid coupling of the kind comprising a bolt having a first conduit therein and a housing mounted for pivotal movement on said bolt when unconstrained, (for example by the bolt not having been tightened to clamp the housing to an abutment) surfaces of the bolt and the housing defining a cavity therebetween, the housing having a generally radially-disposed second conduit connecting with said cavity and the bolt having radial bores connecting the first conduit with said cavity and fluid sealing means between the housing and the bolt. Such a coupling enables the second conduit to be angularly positioned for utmost conveniei;ice in use following which the bolt may be tightened to secure the housing in that position.

In known adjustable fluid-couplings of this kind there are two principal drawbacks.

Firstly, if the housing and shank of the bolt about which the housing pivots are long, then there may be an unnecessarily large pressure drop for fluid flowing from the first conduit through the bores, the cavity and the second conduit. On the other hand, if the bores are too close together, especially if the bores are of large diameter, the bolt may be weakened to the extent that it will be less capable of withstanding the necessary pressure.

The invention provides therefore an adjustable fluid-coupling comprising a). a bolt having a first fluid conduit in its shank, b). a housing mounted for pivotal movement, when unconstrained, on said bolt; and c). sealing means between the bolt and the housing; the coupling being arranged such that walls of the housing and the bolt define an annular space therebetween, there being a second conduit in said housing communicating with said annular space, the bolt having a plurality of bores connecting the first fluid conduit with the annular space, the bores being spaced along the axis of the bolt and angularly spaced about said axis; the diameter of each of the bores being not less than the diameter of the first fluid conduit, and the axial distance between the centres of adjacent bores being such that at any transverse cross section of the bolt in a region pierced by one or more of said bores, the width of the bore or sum of the widths of the bores at that section is substantially equal to or less than the diameter of the first conduit.

Preferably three bores are provided and the axial distance between the centres of adjacent bores is less than a bore diameter.

Preferably peripheral edge surfaces of the bores are, at their radially outer ends relative to the bolt shank, chamfered. Desirably the coupling is aranged such that when the bolt is tensioned, the ratio of the change in axial length of the bolt to the change in axial length of the housing is not greater than 1. The centre of each bore is preferably spaced from the centre of an adjacent bore by about 0.86 of a bore diameter this being the optimum spacing without detriment to the strength of the bolt. The bolt shank in the region of the bores and extending up to the head of the bolt may be of larger diameter than a portion of the shank bearing the bolt threads.

Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section of an adjustable fluid-coupling, shown installed relative to a piece of apparatus, according to the invention, Figure 2 is a part-longitudinal, sectional view of a bolt forming part of the coupling shown in Fig. 1, Figure 3 is a schematic transverse sectional view on line Ill-Ill of Fig. 2, Figure 4 is a view similar to Fig. 2 of a further coupling according to the invention, Figure 5 is a view similar to Fig. 2 of the coupling shown in Figs. 1 to 3, and Figure 6 is a transverse sectional view on line VI-VI of Fig. 5.

The coupling shown in Fig. 1 comprises a hollow bolt 1 and a generally annular housing 2 through which the hollow bolt 1 extends.

The hollow bolt 1 is threadingly engaged in use with a piece of apparatus 10. At both end faces the housing 2 has a soft seal 3 which seals the housing 2 against the hollow bolt 1 and against a surface of the apparatus 10 in use. The hollow bolt has a first conduit 7 and three axially spaced, equi-angularly circumferentially spaced bores 6 with chamfered radially-outer ends 8.

The housing 2 has a second conduit 11, radially disposed, by which, for example, a pipe can be connected to the housing 2 by means of a suitable pipe coupling via screw threaded end 5. The housing 2 has an annular internal recess to define with a surface of the bolt an annular space or cavity 4. This results in the housing 2 being more easily deformable than the bolt 1.

The bores 6 connect the first conduit 7 and the annular cavity 4, and are axially spaced by about 0.86 of the bore diameter, such that at any cross section pierced by one or more of the bores 6, the width of the bore or sum of the widths of the bores at that section is equal to or less than the diameter of a bore 6. This is explained more fully with reference to Figs.

5 and 6 below.

Fig. 2 shows part of a longitudinal section of a hollow bolt 1 showing the disposition of the bores 6 relative to one another.

Fig. 3 shows the angular spacing of the bores 6 entering the first conduit 7.

Fig. 4 shows a coupling in which the hollow bolt 1, in the region of the annular cavity 4, is of larger diameter 14 which compensates for the weakening of the bolt shank by the bores 6.

Fig. 5 is similar to Fig. 2 but a transverse section at line VI-VI of Fig. 5 is shown in Fig.

6 to illustrate the relationship between the axial spacing of the bores and their width in relation to the diameter of conduit 7 (and bores 6). With reference to Fig. 6, each of the bores is axially spaced from an adjacement bore by an amount such that at any transverse cross section in a region of the bolt shank pierced by one or more bores, the width (x or y) or sum of the widths (x + y) is not greater than the diameter D of conduit 7 (or of bores 6). Geometrical analysis indicates that the closest axial spacing of the bores such that the criterion set out above is adhered to is 0.86 D.

The couplings shown in the Figures are so dimensioned that, in use when tensioned, the ratio of the change in axial length of the bolt to the change in axial length of the housing is not greater than 1. It has been found that this provides optimum performance of the coupling, improving the fluid-seal of the coupling even under pulsating fluid loads.

Two, or more than three, bores may be provided, though three are preferred.

Claims

1. An adjustable fluid-coupling comprising, a). a bolt having a first fluid conduit in its shank, b). a housing mounted for pivotal movement, when unconstrained, on said bolt; and c). sealing means between the bolt and the housing; the coupling being arranged such that walls of the housing and the bolt define an annular space therebetween, there being a second conduit in said housing communicating with said annular space, the bolt having a plurality of bores connecting the first fluid conduit with the annular space, the bores being spaced along the axis of the bolt and angularly spaced about said axis; the diameter of each of the bores being not less than the diameter of the first fluid conduit, and the axial distance between the centes of adjacent bores being such that at any transverse cross section of the bolt in a region pierced by one or more of said bores, the width of the bore or sum of the widths of the bores at that section is substantially equal to or less than the diameter of the first conduit.

2. An adjustable fluid-coupling as claimed in claim 1 in which three bores are provided and the axial distance between the centres of adjacent bores is less than a bore diameter.

3. An adjustable fluid-coupling as claimed in claim 1 or claim 2 in which peripheral edge surfaces of the bores are, at their radially outer ends relative to the bolt shank, chamfered.

4. An adjustable fluid-coupling as claimed in any of claims 1 to 3 arranged such that when the bolt is tensioned, the ratio of the change in axial length of the bolt to the change in axial length of the housing is not greater than 1.

5. An adjustable fluid-coupling as claimed in any preceding claim in which the centre of each of the bore is spaced axially from the centre of an adjacent bore by a distance substantially equal to a 0.86 of a bore diameter.

6. An adjustable fluid-coupling as claimed in any preceding claim in which the diameter of the bolt shank in the region of the bores and extending up to the head of the bolt is of larger diameter than a portion of the shank bearing the bolt threads.

7. An adjustable fluid-coupling substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.

8. An adjustable fluid-coupling substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.