LOCKING ARRANGEMENT

Abstract: In a locking arrangement, particularly for alternatively connecting and disconnecting two members (11a, 11b) of a bicycle gooseneck (11), cam followers (19) retained in apertures (51) of one member (11b) are biased by a cam (17) when in a locking position into engagement with corresponding axial grooves (25) in the other member (11a). The cam (17) is rotatable between locking and unlocking position via a security lock (21). A similar arrangement is used in a down hole tool.

Description: Locking Arrangement This invention relates to a locking arrangement for a rotatable member and in particular a locking arrangement for locking rotation of one member relative to another member. The invention has particular, although not exclusive, utility as a securing device for vehicles having a handle bar or steering wheel for steering purposes, whereby the handle bar or steering wheel may be selectively locked into rotation with another member to permit steering of the other member or disconnected from that other member to prevent steering thereof. The locking arrangement may also be used for alternatively connecting and disconnecting two relatively rotatable members of a down hole tool. According to a first aspect, the present invention provides a bicycle locking apparatus having a locking member moveable by means of a security key between a first position in which the bicycle's front wheel is steerable and a second position in which steering of the front wheel is prevented. According to a second aspect, the present invention provides a locking apparatus for alternatively preventing and permitting relative rotation between first and second members, each of which is rotatable about a common axis with respect to a supporting frame characterised in that the first and second members are substantially fixed relative to each other in an axial direction and that the locking arrangement comprises a cam rotatable within a portion of one of the members from a first position at which substantial relative rotation between the members is permitted and a second position at which substantial relative rotation between the members is prevented. The locking apparatus may be adapted for use with a vehicle, which may be a non-motorised vehicle, for example, a bicycle or a tricycle. The locking arrangement may alternatively prevent and permit rotation between, for example, a) a part of a handle bar assembly and a part of a frame adapted to support a steerable wheel; b) a part of an assembly rotatable to steer a wheel and a part of a frame of the vehicle with respect to which the assembly is rotatable; c) a driving shaft of the vehicle rotatable by pedals and a part of a frame of the vehicle with respect to which the driving shaft is rotatable; d) a pedal and a part of a crank with respect to which the pedal is rotatable; e) a wheel and a part of a frame of the vehicle with respect to which the wheel is rotatable. The locking arrangement may be used to prevent relative rotation between the first and second members to permit use of the vehicle or it may be used to permit relative rotation to permit use of the vehicle. The cam is preferably rotatable by means of a cam actuator. The cam may be rotatable from its first to its second position about the common axis of rotation. Alternatively, it may be rotatable from its first to its second position about an axis substantially parallel to the common axis of rotation. The cam may be provided with one or more cam surfaces at its perimeter. Rotation of the cam between its first and second position preferably causes associated movement of the cam surface between respective first and second radial positions to vary the radial distance between the cam surface and the common axis. The cam surface may be displaced axially with respect to the common axis upon movement between its respective first and second radial position. Throughout this description , where the locking arrangement comprises a plurality of a particular element, for example, a plurality of cam surfaces, references to "the element" shall, unless the context otherwise requires, be taken as a reference to the element, each element or at least one of the elements. At its second radial position, the cam surface may co- operate with, or cause a co-operation between, the first and second members to prevent substantial relative rotation therebetween. The locking arrangement may be provided with a cam follower associated with the cam surface, or a plurality of cam followers each associated with the cam surface, with more than one cam surface or with a respective cam surface. The cam follower may be moveable radially with respect to the common axis; it may be moveable between a first position at which substantial relative rotation of the first and second members is permitted and a second position at which it co-operates between the first and second members to prevent substantial rotation therebetween. It may be caused or allowed to move between its first and/or second position by movement of its associated cam surface between its first and/or second position. The cam follower may be caused to move between its first and/or second position by its associated cam surface bearing upon the cam follower. The cam follower may be provided by a roller; it may be substantially cylindrical. The locking arrangement may have one of the first and second members arranged between the cam and the other of the members. Alternatively, the cam may be arranged between the first and second members . In a preferred embodiment, one of the first or second members is arranged with a portion extending around the exterior of a portion of the other member which itself extends around the cam. In this case, the cam may be arranged towards the interior of the locking arrangement with the first member extending around and spaced from the cam and the second member arranged around and spaced from the cam and the first member. Where the first member is arranged between the cam and the second member, its perimeter wall may be provided with one or more apertures. Where a plurality of apertures are provided, they may be spaced radially and/or axially around the perimeter wall. The cam follower may be axially displaced through or partially through an associated aperture when it moves between its first and/or second position. Preferably, in its second position, the cam follower co-operates with the second member to prevent substantial rotation between the first and second members about the common axis . This co-operation may be achieved by the cam follower bearing upon the second member. Preferably, when the cam surface is in its second position it biases its associated cam follower against the second member. The cam surface may bear upon the cam follower and the cam follower may bear upon the second member. The second member may be provided with one or more axially extending grooves located around its perimeter; the grooves may be located opposite the first member. Preferably, when the cam follower is in its second position it co-operates or engages with the or with a respective groove to prevent substantial relative rotation between the first and second members. The groove may be curved in cross-section; it may be substantially semi-circular in cross section. This may facilitate biasing of the cam follower out of co- operation with the groove to allow the cam follower to move from it second position to its first position to permit relative rotation between the first and second members. For example, when the cam surface is in its first position, the cam follower may be biased from its second position to its first position by a torque applied at the first or second member causing a surface of the groove to act against the cam follower to bias the cam follower away from its second position. The groove and the cam follower may have substantially similar radii; the groove may have a slightly greater radius than the cam follower. According to a third aspect, the present invention provides a locking arrangement for locking rotation of one member relative to another member comprising :- a head portion provided on one member having an aperture provided with an axially extending groove disposed at a prescribed angular position around the circumference of the aperture; a stem portion provided on another member to be receivable within the aperture so that the head portion may rotate relative to the stem portion or vice versa, the stem portion having an open socketed end to be disposed within the aperture in coaxial alignment therewith, the wall of the socketed end having a radially extending aperture disposed at a prescribed angular portion around the circumference of the wall capable of being brought into registry with the groove when the head portion and the stem portion are disposed at a prescribed angular position relative to each other; a cam rotatably disposed within the socketed end having a cam surface to define an annular space between the wall and the cam surface of variable radial extent dependent upon the rotatable position of the cam within the socketed end; a cam follower associated correspondingly with the radially extending aperture to be interposed for radial movement between the surface of the aperture and the cam surface within the confines of the radially extending aperture; and a cam actuator to rotate the cam alternatively to: (i) a locking position whereat the head portion and the stem portion are disposed at the prescribed angular position relative to each other and the radial extent of the annular space is at a minimum so that the cam surface biases the cam follower into simultaneous engagement with the groove and the radially extending aperture, locking rotation between the head portion and the stem portion, or to (ii) a rotatable position whereat the radial extent of the annular space is at a maximum so that the cam follower may be biased out of engagement with the groove permitting unimpeded rotation between the head portion and the stem portion. A plurality of grooves, radially extending apertures and cam followers may be provided at prescribed angular positions around the circumference of said aperture and wall respectively such that there is a one-to-one correspondence between the grooves, radially extending apertures and cam followers. Preferably, the grooves, radially extending apertures and cam followers are disposed at equi-angular positions around the perimeter of the aperture and the wall. A plurality of cam portions may be disposed in axially spaced relationship to each other, each cam portion being associated with a corresponding set of cam followers and radially extending apertures to extend axially the bearing obtainable between the cam followers and the grooves when in the locking position. Preferably, one cam and corresponding set of cam followers are angularly offset with respect to another cam and corresponding set to extend angularly the bearing obtainable between the cam followers and the grooves when in the locking position. The cam surface is preferably contoured to form a successive valley and crest associated with a corresponding cam follower and radially extending aperture, whereby when the valley is disposed in radial alignment with the corresponding cam follower and the radially extending aperture, by operation of the cam actuator, the radial extent of the annular space is at a maximum, and when the crest is disposed in radial alignment with the corresponding cam follower and the radially extending aperture, by operation of the cam actuator, the radial extent of the annular space is at a minimum. The cam or cam actuator may be associated with a security device, for example a security key and security lock arrangement, to permit rotation of the cam or cams. The locking arrangement or apparatus may be used on a motor vehicle, a non-motorised vehicle or a two wheeled vehicle. Two or more aspects of the present invention may be combined in a single embodiment. An embodiment of the invention will now be described, by way of example only, with references to the accompanying drawings, wherein: Fig 1 is a side elevation showing a gooseneck of a bicycle comprising both the first and second members; Fig 2 is a top view of Fig 1; Fig 3 is a sectional side elevation of the gooseneck taken along section 3-3 of Fig 2; Fig 4 is a sectional top elevation of the head portion of the one member of the gooseneck taken along section 4-4 of Fig 3; Fig 5 is a sectional side elevation of the other member showing the stem portion thereof, taken along section 5-5 of Fig 1 ; Fig 6 is a sectional top view taken along section 6-6 of Fig 5; Fig 7 is a top view of the cam; Fig 8 is a side elevation of the cam; Fig 9 is a bottom view of the cam; Fig 10 is a top view of the packing flange; Fig 11 is a side elevation of a cam follower; Fig 12 is a top view of Fig 11; and Fig 13 is a cross-section of part of a down hole tool incorporating a locking arrangement. Figs 1 to 12 illustrate a locking arrangement which functions as a security device for a bicycle and is fitted in the gooseneck of a bicycle, connecting the handlebars to the front forks of the bicycle. The gooseneck 11 comprises two parts, one member 11a to which the handlebars (not shown) of the bicycle are clamped in the conventional manner, and another member lib which is clamped to a frame (not shown) incorporating the front forks of the bicycle so that rotating the handlebars may cause rotation of the frame incorporating the forks for steering the front wheel of the bicycle. In the conventional gooseneck arrangement, the members are fixed relative to each other to directly transfer movement of the handlebars to rotation of the fork frame. In the present embodiment, however, the members are capable of rotation relative to each other. The locking arrangement is incorporated into the design of the gooseneck to selectively lock rotation of the one member 11a relative to the other member lib to permit steering, or alternatively to disengage the locking arrangement between the members permitting rotational movement of the one member 11a relative to the other member lib, thus making the bicycle unsteerable. The locking arrangement generally comprises a head portion 13 provided on the one member 11a, a stem portion 15 provided on the other member lib, a cam 17 interconnecting the head portion and the stem portion, cam followers 19 associated with the cam, and a cam actuator 21. The head portion 13 is formed at an end of the one member 11a opposite to the end which is clampingly attached to the handlebars. The head portion is formed with an aperture 23 so as to effectively form a sleeve within which the end of the stem portion 15 is disposed. The aperture 23 is provided with a series of axially extending grooves 25 which are disposed at prescribed equi-angular positions around the circumference of the aperture. The grooves are curved in cross-section in a semi-circular manner for reasons which will become apparent. The stem portion 15 is a clamped within a socket of the fork frame in a conventional manner by means of an anchor bolt 27 and plug 37 disposed within a central bore 29 formed within the other member lib. The anchor bolt and plug are arranged so that a head 31 of the bolt is disposed against a seat formed at one end of the bore 29 adjacent to the end of the stem in which the cam is located. A shank 33 of the bolt extends axially along the bore to threadedly receive the threaded end of the stem 35 to which is mounted the plug 37. The shank 33 of the anchor bolt 27 is hollow and internally threaded to receive the external thread of the stem 35. The plug 37 is receivable within a recess 39 provided at the other end of the bore and is of conical shape so as to frictionally engage the inner periphery of the wall 41 of the other member lib defined by the recess 39 so that tightening of the anchor bolt causes the plug 37 to be drawn towards the head 31 causing the wall to expand radially and thereby clamping the other member lib within the accommodating socket of the fork frame. The end of the stem portion 15 receivable within the aperture 23 of the head portion 13 is socketed to define an inner recess 43 which communicates with the bore 29 to define a seat 30 on which the head 31 of the anchor bolt sits, and a recess 45 which receives the cam 17. The inner and outer recesses 43 and 45 are disposed within the socketed end of the stem portion in co-axial alignment with the aperture 23 of the head portion. The outer recess is of marginally larger diameter than the inner recess to define an annular seat 47 on which the cam 17 sits. The outer recess 45 defines an annular wall 49 which is provided with a series of radially extending apertures 51 disposed at prescribed equi-angular positions around the circumference of the wall 49. The radially extending apertures 51 are divided up into two sets, the apertures of each set being disposed in the same radial plane and the sets being axially spaced from each other so as to define an outer set of apertures 51a and an inner set of apertures 51b. Each set of apertures 51 is angularly offset to the other and is arranged to correspond with the grooves 25 of the aperture 23. In the present embodiment, each radially extending aperture 51 and groove 25 is angularly disposed 60° from adjacent radially extending aperture and groove, respectively, to provide a total of six radially extending apertures and six grooves. The radially extending apertures are divided so that the apertures in one set are angularly disposed 120° from the adjacent apertures within the same set, thereby providing three radially extending apertures per set. The end of the stem portion 15 is accommodated within the aperture 23 of the head portion 13 so that the head portion may rotate relative to the stem portion, or vice versa. Accordingly, the grooves 25 of the head portion may be collectively brought into or out of registry with the corresponding radially extending apertures 51 of the stem portion by rotating the head portion relative to the stem portion or vice versa. In operation, the prescribed angular position of the grooves and radially extending apertures co-incide with the grooves and apertures being brought into registry with each other when the head portion of the gooseneck disposes the handlebars at the required angular position relative to the fork frame. The cam 17 comprises a pair of cams 53 disposed on opposite sides of the central circular flange 55, the latter being of commensurate diameter to the diameter of the outer recess 45 so as to be accommodated therein. Furthermore, the overall radial extent of each cam 53 is marginally larger than the diameter of the inner recess 43 to enable location and retention of the cam within the outer recess. The cam is disposed within the outer recess 45 so that an upper cam 53a is located in co-planar relationship with the outer set of radially extending apertures 51A and a lower cam 53b is located in co-planar relationship with the lower set of radially extending apertures 53b. The cam surface 57 extends axially and is formed with a succession of valleys 59 and crests 61 in corresponding relationship with the radially extending apertures 51 and grooves 25 so that there is a one-to-one correspondence between an adjacent valley 59 and crest 61 forming a single cam surface and a corresponding radially extending aperture 51 and groove 25. Thus, each radially extending aperture and corresponding groove has associated therewith a particular cam surface 57 comprising a single valley and crest. Consequently, three discrete cam surfaces are provided on each cam which combine to define an annular space of variable radial extent between the wall 49 and the cam surface 57 of each cam. The cam 17 is rotatable within the outer recess by the action of the cam actuator 21 in a manner to be described later so that the annular space between a radially extending aperture 51 and the cam surface 57 thereof may be varied between a maximum distance corresponding to a valley being disposed in opposite radial alignment with the aperture, and a minimum distance corresponding with a crest being disposed in opposite radial alignment with the aperture. The cam followers 19 are of circular cylindrical form and are associated correspondingly with the radially extending apertures so that one cam follower 19 is interposed between the surface of the aperture 23 of the head portion 13 and a cam surface 57, within the confines of a corresponding radially aperture 51. Each cam follower 19 is disposed so that the parallel planar ends 63 thereof are disposed transversely of the axial extent of the apertures 23 in the socketed end of the stem portion so that the circular surface 65 thereof may bear against the cam surface 57 and the surface of the aperture 23 when brought into engagement therewith. Accordingly, by variation of the radial extent of the annular space between the wall 49 and cam surface 57, the cam follower 19 is capable of radial movement through the radially extending aperture. Importantly, the diameter of the cam follower 19 is of a predetermined size to simultaneously engage a groove 25 and the wall 49 surrounding the radially extending aperture when the groove and the radially extending aperture are brought into registry, simultaneously with the crest 61 associated with the radially extending aperture being brought into opposite radial alignment with the aperture. Furthermore, each cam surface 57 is required to be precisely shaped so that the radial extent of the annular space between the wall and the cam surface is sufficient to accommodate a cam follower 19 therein so that the outermost surface of the cam follower sufficiently disengages from the groove which it previously engaged when a valley 59 of the cam surface 57 thereof is brought into opposite radial alignment with the radially extending aperture, to permit free rotatable movement of the head portion relative to the stem portion. The cam actuator 21 is in the form of a key operated lock located in the aperture 23 of the head portion. The lock comprises a barrel 67 which is rotatably disposed within a barrel housing 69 fixedly located within the top of the aperture 23 by means of a grub screw 71, and a lever 73 fixedly attached to the barrel and extending axially thereof to be accommodated within a central bore 75 provided in the cam 17. The lever 73 is elongated in cross-section in conjunction with the central bore 75 so that rotation of the lever causes corresponding rotation of the cam 17. The barrel 67 of the lock is of conventional, construction, being operated by insertion of an appropriately shaped key into the keyway thereof and by turning the key in an appropriate direction to cause rotation of the cam. The lock is designed so that rotation of the barrel causes the cam to rotate either to a locking position or to a rotatable position. At the locking position, the head portion 13 and the stem portion 15 are locked to each other to prevent relative rotation therebetween. This is achieved by the cam being rotated so that the crest 61 of each cam surface 57 is disposed in opposite radial alignment with the corresponding radially extending apertures 51 so that the annular space between the wall 49 and the cam surface 57 is at a minimum. To enable such rotation of the cam 17, the grooves 25 of the aperture 23 must be brought into registry with the corresponding radially extending apertures 51 of the stem portion so that the crest 61 of the cam surfaces bias the respective cam followers 19 outwardly into engagement with the grooves 25 and the wall 49 surrounding the radially extending apertures. At this position, the cam followers 19 lock rotation between the head portion and the stem portion permitting steering of the bike by way of the fixed gooseneck arrangement. At the rotatable position the barrel 67 of the lock is rotated so that the cam 17 is disposed with each of the valleys 59 of the cam surfaces disposed in opposite radial alignment with each of the corresponding radially extending apertures 51 so that the radial extent of the annular space between the wall 49 and the cam surfaces is at a maximum. At this position, the cam followers 19 can be biased out of engagement from the grooves by rotation of the head portion. Such rotation causes the side of the grooves to push each of the cam followers 19 radially inward through the radially extending apertures 51 since the crest 61 of the cam surfaces are no longer disposed in opposite radial alignment to the radially extending apertures to prevent such inward movement. Thus, the cam followers are pushed inwardly to be accommodated in the space between the wall 49 and the valleys 59 of the cam surface, thereby being biased out of engagement from the grooves 25 to subsequently permit unimpeded rotation of the head portion relative to the stem portion. It should be appreciated that the scope of the present invention is not limited to the particular embodiment described herein. For example, the invention is not limited to a dual cam and set of radially extending apertures, but may include a single cam and set of radially extending apertures. Furthermore, the prescribed angular position of the grooves, radially extending apertures, cams surfaces and cam followers need not be equi-angular but may adopt an angular arrangement whereby all of the grooves only register with all of the radially extending apertures at one prescribed angular position between the head portion and stem portion. Fig 13 shows a locking arrangement used in association with a down hole tool 100 (illustrated in cross-section about centre line 200) which has a first drill pipe 101 connected to a second drill pipe section 102. The locking arrangement comprises a plurality of cam followers in the form of rollers 103 carried in apertures in a circumferential wall 104 of an end of the second drill pipe 102 which is arranged within an end of the first drill pipe 101. Rotation of the cam 105 to a locking position causes outward movement of the rollers to co-operate with associated annular grooves 106 at a wall of the first drill pipe 101 to lock the pipes 101,102 together for rotation. The cam 105 is rotated to its locking position in the following way: a. an actuator in the form of a dart 110 is fed down an internal bore of the drill pipe; b. a pressurised fluid P is caused to act at the rear 111 of the dart 110 to force a tapered leading edge 112 of the dart to act against a co-operating activating edge 113 of a sleeve 114; c. the sleeve 114 is thus forced to slide downwardly; d. a portion of the sleeve 114 passes through and co- operated with a central aperture of the cam 105 by means of an auger thread. Downward movement of the sleeve 114 thus causes rotation of the cam 105 to its locking position. The sleeve 114 is biased to its unlocking position by means of a plurality of compression springs 115. When the fluid pressure P acting on the dart 110 is released, relative rotation between the first and second pipes 101,102 will tend to push the rollers 103 inwardly to their unlocked position. This biasing, and the biasing of springs 115, causes the cam 105 to rotate to its unlocked position to release the locking arrangement . A plurality of locking arrangements may be arranged at spaced positions along a string of drill pipes. Each locking arrangement may have an associated dart. The dart for the lowermost locking arrangement may be dimensioned or arranged so that it can pass through the uppermost locking arrangements. In an alternative arrangement, the dart 110 causes radial expansion of the sleeve 114 to rotate the cam 105 to its locking position.

Claims: Claims 1 A bicycle locking apparatus having a locking member (17) moveable by means of a security key between a first position in which the bicycle's front wheel is steerable and a second position in which steering of the front wheel is prevented. 2 An apparatus in accordance with Claim 1 in which, in its second position, the locking member serves to disconnect the handle bars from the frame incorporating the front forks of the bicycle. 3 An apparatus in accordance with Claim 1 or Claim 2 in which the apparatus is arranged at a bicycle gooseneck (11) between a first member (11a) connectable to the handle bars and a second member (lit") connectable to the frame incorporating the front forks of the bicycle. 4 An apparatus in accordance with any preceding claim in which the locking member comprises a rotatable cam (17). 5 A locking apparatus for alternatively preventing and permitting relative rotation between first (H a ) an< 3 second (lib) members, each of which is rotatable about a common axis with respect to a supporting frame characterised in that the first (H a ) an d second (lib) members are substantially fixed relative to each other in an axial direction and that the locking arrangement comprises a cam (17) rotatable within a portion of one of the members (11a, lib) from a first position at which substantial relative rotation between the members (11a, lib) is permitted and a second position at which substantial relative rotation between the members (11a, lib) is prevented. 6 A locking apparatus in accordance with Claim 4 or Claim 5 in which the apparatus comprises at least one cam follower (19) which, when the cam (17) is in its first position, is retained by the cam (17) in a locking position in which it causes a cooperation between the first (11a) and second (lib) members to prevent substantial relative rotation therebetween and when the cam (17) is in its second position is moveable to an unlocked position to permit relative rotation between the first (11a) and second (lib) members. 7 A locking apparatus in accordance with Claim 6 in which the cam follower (19) is provided in the form of a roller. 8 A locking apparatus in accordance with Claim 6 or Claim 7 in which, in its locking position, the cam follower (19) co-operates with a recess (25) provided at the first member (11a). 9 A locking apparatus in accordance with Claim 8 in which the recess is provided as an axially extending groove (25) in the first member. 10 A locking apparatus in accordance with Claim 8 or Claim 9 in which the apparatus has a plurality of cam followers (19) and a plurality of associated recesses (25) provided at the first member . 11 A locking apparatus in accordance with any one of Claims 6 to 10 in which the or each cam follower (19) is located in an aperture (51a, 51b) provided in the second member (lib). 12 A locking apparatus in accordance with any one of Claims 5 to 11 in which the first member (Ha) is a driving member and the second member (lib) is a driven member . 13 A locking apparatus in accordance with any one of claims 4 to 12 in which the cam (17) is rotatable by means of axial movement of a co-operating member ( 114 ) . 14 A locking apparatus in accordance with Claim 13 in which the co-operating member (114) extends through an aperture (115) passing substantially axially through the cam (17). 15 A locking apparatus in accordance with Claim 13 or Claim 14 in which the co-operating member (114) and the cam (17) co-operate by means of an auger screw thread. 16 A locking apparatus in accordance with any one of claims 13 to 15 in which at least one resilient member (115) biases the co-operating member (114) to a position in which the cam is arranged at an unlocked orientation. 17 A locking apparatus in accordance with any one of claims 13 to 16 in which the co-operating member (114) is adapted to be moved axially to move the cam (17) to a locking position by application of a presurised fluid. 18 A locking apparatus in accordance with claim 17 in which the presurised fluid is arranged to act upon an actuator (110) which, in turn, acts upon the co-operating member (114). 19 A locking apparatus in accordance with Claim 18 in which the actuator (110) is removable from the apparatus . 20 A locking apparatus in accordance with any one of claims 4 to 19 in which the cam (17) is rotatable by means of a security key. 21 A locking arrangement for locking rotation of one member (Ha) relative to another member (lib) comprising a head portion (13) provided on one member (Ha) having an aperture (23) provided with an axially extending (25) groove disposed at a prescribed angular position around the circumference of the aperture (23); a stem portion (15) provided on the other member (lib) to be receivable within the aperture (23) so that the head portion (13) may rotate relative to the stem portion (15) or vice versa, the stem portion (15) having an open socketed end to be disposed within the aperture (23) in coaxial alignment therewith, a wall (49) of the socketed end having a radially extending aperture (51) disposed at a prescribed angular position around the circumference of the wall (49) capable of being brought into registry with the groove (25) when the head portion (13) and the stem portion (15) are disposed at a prescribed angular position relative to each other; a cam (17) rotatably disposed within the socketed end having a cam surface (57) to define an annular space between the wall and the cam surface (57) of variable radial extent dependent upon the rotatable position of the cam (17) within the socketed end; a cam follower (19) associated correspondingly with the radially extending aperture (51) to be interposed for radial movement between the surface of the aperture (23) and the cam surface (57) within the confines of the radially extending aperture (25); and a cam actuator (21) to rotate the cam (17) alternatively ( i ) to a locking position whereat the head portion (13) and the stem portion (15) are disposed at the prescribed angular position relative to each other and the radial extent of the annular space is at a minimum so that the cam surface (57) biases the cam follower (19) into simultaneous engagement with the groove (25) and the radially extending aperture (51), locking rotation between the head portion (13) and the stem portion (15), or to (ii) a rotatable position whereat the radial extent of the annular space is at a maximum so that the cam follower (19) may be biased out of engagement with the groove (25) permitting unimpeded rotation between the head portion (13) and the stem portion (15). A locking arrangement in accordance with Claim 21 in which a plurality of grooves (25), radially extending apertures (51) and cam followers (19) are provided at prescribed angular positions around the circumference of said aperture (23) and wall (49) respectively such that there is a one to one correspondence between the grooves (25), radially extending apertures (51) and cam followers (19) . 22 A locking arrangement in accordance with of Claim 21 or Claim 22 in which a plurality of cam portions (57) are disposed in axially spaced relationship to each other, each cam portion being associated with a corresponding set of cam followers (19) and radially extending apertures (51a, 51b) to extend axially the bearing obtainable between the cam followers (19) and the grooves (25) when in the locking position. 23 A locking arrangement in accordance with Claim 22 in which one cam and corresponding set of cam followers are angularly offset with respect to another cam and corresponding set to extend angularly the bearing obtainable between the cam followers and the grooves when in the locking position. 24 A locking arrangement in accordance with any one of Claims 21 to 23 in which the cam actuator (21) has an associated security device to selectively permit or prevent rotation of the cam or cams. 25 A locking arrangement in accordance with any one of Claim 21 to 24 arranged to alternatively prevent and permit rotation between a part of a handle bar assembly of a bicycle and a part of a frame adapted to support a steerable wheel. 26 A locking arrangement in accordance with any one of Claims 21 to 24 arranged to alternatively prevent and permit rotation between first and second members of a down hole tool . 27 A bicycle provided with a locking arrangement or apparatus in accordance with one of Claims 1 to 25. 28 A down hole tool provided with a locking arrangement or apparatus in accordance with any one of Claims 5 to 24. 29 A locking arrangement substantially as hereinbefore described with reference to one or more of the accompanying drawings. 30 A down hole tool substantially as hereinbefore described with reference to one or more of the accompanying drawings. 31 A bicycle substantially as hereinbefore described with reference to one or more of the accompanying drawings.

Inventors: DINSE JOHN, DINSE, JOHN
Applicants: DINSE JOHN, DINSE, JOHN
Application year: 1996
Main classification: B62H5
IPC codes: B62H5, B62K21