LOCKABLE COUPLING

Abstract: A cam lever (8) for a cam and groove coupling of the type having a male coupling member (2) that includes a groove (3) for engagement with one or more cams (16) provided on a corresponding female coupling member (1). The cam lever (8) includes a cam (16) and the cam lever (8) is selectively positionable to position the cam (16) to engage or disengage the male (2) and female (1) coupling members. The cam lever (8) also has locking mechanism (24) which may be engaged to maintain the cam (16) in position in which the coupling members are engaged. The engagement of the locking means (24) is independent of the external surfaces of the female coupling member (1) which provides the advantage that the locking mechanism (24) is unlikely to snag on other objects in use and thus inadvertently open which can be a problem with prior art constructions.

Description: FIELD OF THE INVENTION This invention relates to locking apparatus The invention has been devised particularly, but not solely, for locking cam and groove couplings for hoses and/or conduits which require some form of safety locking device to prevent inadvertent opening or release of the coupling BACKGROUND (a) Prior Art Cam and groove couplings are a common form of coupling The coupling generally comprises a male coupling member and a female coupling member The female coupling member usually has two cam levers the cams of which may be positioned in an engaged state to engage the cam with a groove in the male member to form the coupling Cam and groove couplings are usually used to connect hoses and/or conduits, such as liquid supply hoses or conduits together for transferring liquids In particular, cam and groove couplings are often used to join hoses or conduits which transport liquids which could cause dangerous spills if the coupling were to be inadvertently released For example, fuels such as gasoline, oil etc are often transferred between containers using hoses or conduits that incorporate cam and groove couplings Other products such as acidic, caustic or other dangerous or environmentally harmful chemicals are ajso transferred using hoses or conduits which incorporate cam and groove couplings In order to avoid the inadvertent release or opening of cam and groove couplings, at least one locking mechanism, marketed under the trade mark BOSS- LOCK, has been devised to keep the cam levers in the position required to maintain the coupling in the engaged state The locking mechanism comprises a selectively engageable pin provided on the cam handle, the pin being engaged with the aperture on the outside of the female coupling member in order to lock the mechanism and thus prevent the cam lever moving to the release position SUBSTITUTE SHEET This known locking mechanism has a number of disadvantages Firstly, it requires a non-standard or modified form of female coupling member to provide the engagement aperture for the locking pin Furthermore, the provision of the locking aperture on an external part of the female coupling member creates an additional s problem in that there is another protrusion or fixture on the outside of the coupling which can snag on other objects when the coupling is in use This potential problem for snagging is extremely undesirable, as snags can in some cases release the locking pin or otherwise damage it resulting in the release of the coupling Finally, these known locking mechanisms have the disadvantage that pull rings, or finger 10 rings or the like are required in order to release the locking pin from the lock position These rings provide a further feature which can snag in use and cause release problems, or problems with movement of the conduit in use It is an object of the present invention to provide a cam and groove coupling i or a female coupling member of a cam and groove coupling, or a cam lever for a cam and groove coupling, or locking means for a cam and groove coupling which will at least go some way toward overcoming the foregoing disadvantages, or which will at least provide the public with a useful choice 0 (b) General Discussion of the Invention In one aspect the invention consists in a cam lever for a cam and groove coupling having a male coupling member and a female coupling member, the cam lever including a cam, the cam lever being selectively positionable to position the cam to engage the male and female coupling members so that they are in an i engaged state, or disengage the male and female coupling members so that they are in a disengaged state, and having locking means to maintain the cam in a position in which the coupling members are engaged, the engagement of the locking means being independent of an external surface of the female coupling member 30 To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims which the following gives examples DRAWING DESCRIPTION s One preferred form of the invention will now be described with reference to the accompanying drawings in which Figure 1 is a diagrammatic front elevation of a cam and groove coupling in accordance with the present invention, 0 Figure 2 is a front elevation of a cam lever in accordance with the present invention, Figure 3 is a plan view of the cam lever of Figure 2, s Figure 4 is a front elevation of a locking assembly including a locking member in accordance with the present invention, Figures 5 and 6 are front elevations of the cam lever of Figures 2 and 3 including the locking assembly of Figure 4 showing the locking assembly in the engaged position 0 (Figure 5) and in the disengaged position (Figure 6), Figure 7 is a front elevation in partial cross-section showing the cam lever of Figures 5 and 6 in a disengaged position, and Figure 8 is a front elevation in partial cross-section showing the cam lever of Figure 7 in an engaged position DETAILED DESCRIPTION Referring to Figure 1 , a coupling which is commonly referred to as a cam and 0 groove coupling is shown The coupling comprises a female coupling member 1 and a male coupling member 2 which in use may be attached to respective hoses and/or conduits 4 and 6 which usually transport liquids such as water, gasoline, oil or various chemical products, for example SUBSTITUTE SHEET The female coupling member 1 has two cam levers 8 which are pivotally connected to the female coupling member 1 by pivotal connection 10 The male coupling member has a groove 3 which cams (described further below) on a cam (described further below) of each of the cam levers 8 so that the male and female coupling members engage to form the required coupling In the position shown in Figure 1 , the cam levers 8 are in a position which corresponds to a disengaged state for release of the male coupling member 2 from the female member 1 The cam levers 8 are free to move about the pivot pin 10 in a direction as indicated by arrows 12 in order to be disposed in a position such as that shown in dotted outline 14 in which the cams are in a position corresponding to an engaged state whereby they engage with the groove 3 male member is (if present) Referring to Figure 2, the cam lever 8 is shown in more detail It can be seen that the cam lever comprises a cam portion 16 having a contoured surface generally referenced 17 and a cam handle portion 18 An aperture 20 is provided for receiving the pivot pin 10 to provide the pivotal connection with the female member 1 The cam handle of Figure 2 has a recessed portion 22 which in use contains a locking assembly which will be discussed further below Referring to Figure 3, the lever of Figure 2 is shown from above in plan view to clarify the position of the recessed portion 22 and the pivot aperture 20 Figure 4 shows the locking assembly which is in use located in the recessed portion 22 of the cam handle The locking assembly is generally referenced 24, and comprises a locking member 25 having an engagement portion 26, a control or release lever 28 which may comprise a thumb screw or the like, a biasing means 30 which preferably comprises a coil spring, a collar 29 to retain the spring 30, and retainer 31 to retain the non-engaging end 35 of the locking member 25 Referring to Figure 5 the locking member 25 is shown in the position in which it is normally disposed by spring 30, which is a position corresponding to the coupling being in the engaged state so that engagement portion 26 engages with a part of the coupling to prevent release of the cam until the release lever 28 is moved against the spring 30 (to the right in figures 5 and 6 to the release position as shown in figure 6 engagement portion 26 from the coupling so that the cam may be moved to the position corresponding to the coupling being in the disengaged state In the position shown in figure 6 the engagement portion is retracted so that it is almost, or s completely, within the cam portion 16 of the cam lever 8 Once the lever 28 is released, it will be seen that the spring 30 will return the locking assembly to the position shown in Figure 5 Turning to Figure 7 the cam lever is shown in the release position with the 0 female coupling member 1 and the male coupling member 2 shown in a position ready for engagement The action of engagement by which the male coupling member is forced onto a bush or gasket 32 by the action of the cam 16 against the groove 3 As the cam handle 18 is rotated downward in a direction indicated by arrow 34 in figure 7, the locking member 26 is forced back into the cam handle 8 and then it slowly begins to extend back out from the cam handle as it follows the contour of the groove 3 until it reaches the position shown in Figure 8 Referring to Figure 8, it can be seen that the cam handle 8 is in the locked position so that the male and female coupling members are forced together and are 0 unable to be released without release of the locking means and rotation of the cam lever The engagement portion 26 has extended out away from the cam handle 8 past edge 33 of groove 3 so that edge 33 prevents the handle 8 from being rotated back to the position shown in Figure 7 Thus the handle 8 is effectively locked in a closed position which prevents the coupling from being released S It will be seen that the locking member may be configured so as to engage with parts of the coupling other than the male member 2 For example, the locking member may be configured so as to engage with the lower lip 37 of the female housing, or other adjacent parts of the female housing such as the sides (not shown) 0 of the aperture in the female housing in which the cam 16 is in use disposed These constructions all provide the advantage that the locking engagement requires no modification of the standard cam and groove coupling, and as the engagement is independent of external surfaces of the female coupling member, there is minimal risk of snagging or inadvertent release in use B TIT TE It will be seen that the invention has a number of other advantages Firstly, the locking assembly is essentially located within the cam handle 8 and is s independent of the female coupling member or any other non-standard features of the coupling Therefore, the male and female coupling members do not need to be modified in any way whatsoever to accommodate the locking mechanism so cam handles are easily interchanged between couplings Therefore, the cam lever which includes the locking assembly of the present invention can be installed on any 10 authorised standard cam and groove coupling without any modification to the coupling itself being required This is a significant advantage, as it means that standard couplings can be effectively changed to locking couplings by simply replacing the old handle with the present invention i The other significant advantage is that the locking means of the present invention is incorporated in a standard handle which has no protrusions or protuberances which are likely to snag when the coupling is in use Furthermore, even if the coupling does snag, the likelihood of the coupling 0 being released is extremely remote because the operating lever 28 of the locking assembly is very small and is almost completely protected by the pivotal connection support 36 (figure 8) of the female coupling member

Claims: 1 A cam lever for a cam and groove coupling having a male coupling member and a female coupling member, the cam lever including a cam, the cam lever being s selectively positionable to position the cam to engage the male and female coupling members so that they are in an engaged state, or disengage the male and female coupling members so that they are in a disengaged state, and having locking means to maintain the cam in a position in which the coupling members are engaged, the engagement of the locking means being independent of an external surface of the 10 female coupling member 2 A cam lever as claimed in claim 1 wherein the locking means includes an engagement means which engages with a part of the coupling to maintain the cam in the engaged state, the engagement means being provided adjacent to the cam i s 3 A cam lever as claimed in claim 1 or claim 2 wherein the locking means is provided substantially within the cam lever 4 A cam lever as claimed in any one of the preceding claims wherein the locking 0 means include release means for releasing the engagement means to allow the cam to be repositioned form the engaged state to the disengaged state 5 A cam lever as claimed in claim 4 wherein the release means does not substantially protrude beyond the cam lever 5 6 A cam lever as claimed in any one of the preceding claims wherein the cam lever is interchangeable with other cam and groove couplings 7 A cam lever substantially as herein described with reference to, and as illustrated 0 by, the accompanying drawings 8 A female coupling member for a cam and groove coupling, the female coupling member having a cam lever as claimed in any one of the preceding claims SUBSTITUTE SHEET . cam an groove coup ng avng a mae coup ng mem er an a emae coupling member, the female or the male coupling member having a cam lever as claimed in any one of the preceding claims. 10. Any new feature or combination of features disclosed herein. SUBSTITUTE SHEET

Inventors: MCKENZIE WARWICK ANDREW, MCKENZIE, WARWICK, ANDREW
Applicants: MCKENZIE WARWICK ANDREW, MCKENZIE, WARWICK, ANDREW
Application year: 1997
Main classification: F16L15
IPC codes: F16L37