FOLDING BICYCLE WHEEL

Abstract

A bicycle wheel includes a hub, a rim and spoke members extending between the hub and the rim; the hub comprising a plurality of hub members, wherein the wheel comprises three or more sectors, each sector comprising a circumferential rim section, an axial hub member and one or more spoke members extending between the hub member and the rim portion, wherein the wheel may be moved between a deployed configuration and a fully collapsed configuration, wherein in the deployed configuration the rim portions form a continuous circular rim of the wheel, wherein in the fully collapsed configuration the rim portions are arranged side by side in an axially adjacent arrangement, and wherein the hub members engage and form an axially expandable or collapsible hub.

Claims

1. A bicycle wheel, comprising: a hub comprising a plurality of hub members; a rim; and spoke members extending between the hub and the rim; wherein the wheel comprises three or more sectors, each sector comprising a circumferential rim section, an axial hub member and one or more spoke members extending between the hub member and the rim portion; wherein the wheel may be moved between a deployed configuration and a fully collapsed configuration; wherein in the deployed configuration the rim portions form a continuous circular rim of the wheel; wherein in the fully collapsed configuration the rim portions are arranged side by side in an axially adjacent arrangement; and wherein the hub members engage and form an axially expandable or collapsible hub.

2. The bicycle wheel as claimed in claim 1, wherein the hub includes a shaft extending axially of the wheel; and further comprising: a collar located co-axially around the shaft, the collar comprising three or more part cylindrical collar members, the collar members being axially slidable and rotatable in relation to the other collar members.

3. The bicycle wheel as claimed in claim 1, wherein each hub member comprises a respective collar member, each collar member forming the hub member or extending radially outwardly from the hub member.

4. The bicycle wheel as claimed in claim 3, wherein each collar member is axially slidable in relation to one or two other collar members.

5. The bicycle wheel as claimed in claim 3, wherein each collar member comprises a body having a part-cylindrical internal surface and one or more mountings for a spoke member, preferably two spokes, of a respective rim portion.

6. The bicycle wheel as claimed in claim 1, further comprising: a first collar member secured to the hub shaft, the first collar member extending outwardly from the shaft, and having first and second engagement surfaces extending parallel to the axis of the shaft, each of the engagement surfaces being arranged for slidable engagement with a corresponding engagement surface of an adjacent collar member.

7. The bicycle wheel as claimed in claim 6, wherein each engagement surface includes a formation configured to engage a complementary formation of a corresponding engagement surface of an adjacent collar member.

8. The bicycle wheel as claimed in claim 6, wherein the or each projection comprises one or more axially extending ribs or spines, and wherein the or each projection extends tangentially to the axis.

9. The bicycle wheel as claimed in claim 8, wherein the or each projection extends at a constant radius from the axis, and having a cylindrical profile.

10. The bicycle wheel as claimed in claim 8, wherein the engagement surfaces are planar or curved in cross-sectional profile.

11. The bicycle wheel as claimed in claim 1, further comprising: first second and third collar members arranged around the cylindrical shaft member, the first collar member being secured to or integral with the shaft and having first and second engagement surfaces arranged to engage and cooperate with a third engagement surface of a second collar member and a fourth engagement surface of a third collar member respectively; and a fifth engagement surface of the second collar member being arranged to engage a sixth engagement surface of the third collar member.

12. The bicycle wheel as claimed in claim 8, wherein when the engagement surfaces are engaged in this way, the second, third or both collar members move slidingly along the shaft relative to each other and/or the first collar member and are prevented from axial rotation by abutment of each collar member between engagement surfaces of the two adjacent collar members.

13. The bicycle wheel as claimed in claim 6, wherein the engagement surfaces of the first collar member have one or more projections or recesses extending at a constant radius, so that the projections and recesses are part cylindrical in radial cross-section.

14. The bicycle wheel as claimed in claim 6, wherein the first collar member has one or more of: two recesses, one on each engagement surface; two projections, one on each engagement surface; or one projection and one engagement on one projection and one engagement surface and one recess on the other engagement surface.

15. The bicycle wheel as claimed in claim 6, wherein the second and third collar members slide axially along the shaft in opposite directions.

16. The bicycle wheel as claimed in claim 6, wherein a locking member secures one or both of the collar members to the shaft.

17. The bicycle wheel as claimed in claim 16, wherein the locking member comprises a pin that extends through a radially extending bore in the body of the second or third collar member and be received in a socket in the shaft, the pin being biased, for example by a spring, into the engaged position in which the pin is engaged within the socket so that movement of the collar relative to the shaft is prevented.

18. The bicycle wheel as claimed in claim 17, wherein the shaft includes one or more channels, the or each channels being configured to guide the pin as the respective collar member is moved axially along the shaft.

19. The bicycle wheel as claimed in claim 18, wherein the channel is configured to engage an end of the pin as the collar member is moved axially outwardly of the hub between the deployed position and towards the fully collapsed position.

20. The bicycle wheel as claimed in claim 19, further comprising a first channel in the shaft serves to guide the movement of the guide pin extending radially inwardly from the second hub member, the first channel extending parallel to the axis of the shaft for a first distance and between a first end and a second end and extending circumferentially from the second end at a constant location on the wheel axis.

21. The bicycle wheel as claimed in claim 20, further comprising a second channel in the surface of the shaft serving to guide movement of the third hub member.

22. The bicycle wheel as claimed in claim 21, wherein the first section of the second channel extends along the surface of the shaft in a spiral configuration and a second section of the second channel extends at a constant axial location along the wheel axis.

23. The bicycle wheel as claimed in claim 3, further comprising: a collar clamp to secure the collar members in the deployed configuration of the wheel.

24. The bicycle wheel as claimed in claim 23, wherein the collar clamp is arranged to apply a radially, inwardly-directed force against a radially, outwardly-facing surface of two collar members.

25. The bicycle wheel as claimed in claim 1, wherein adjacent rim sections are secured together in the deployed position by a rim lock arrangement, wherein the rim lock arrangement comprises a channel extending circumferentially into an end of each rim section and arranged to align with a corresponding channel extending into the end of an adjacent rim section to form a continuous channel in the deployed configuration of the wheel, and further comprising a latch member being located in the channel, the latch member being slidable between a retracted position wherein the latch member is located wholly within a single channel and an extended position wherein the latch member is located partially within each channel of two adjacent rim sections.

26. The bicycle wheel as claimed in claim 1, wherein each rim section supports a respective tyre section, each tyre section having end walls arranged to abut the end walls of an adjacent tyre section when the wheel is in the deployed configuration.

27. The bicycle wheel as claimed in claim 2, wherein a bearing is located between the shaft and collar.

28. The bicycle wheel as claimed in claim 25, wherein the rim lock arrangement comprises a rim clamping member engaging adjacent rims and applying a clamping force to the rims to prevent relative movement of the rims.

29. A foldable bicycle, comprising: a frame; and two wheels; the frame comprising two parts connected together by lockable hinges and movable between a first position in which the frame is extended for riding by a user and a second position in which the frame is folded; a front wheel detachable from the frame; and a rear wheel as claimed in claim 1.

30. A foldable bicycle, comprising: a frame; and two wheels; the frame comprising two parts connected together by lockable hinges and movable between a first position in which the frame is extended for riding by a user and a second position in which the frame is folded; a front wheel and a rear wheel as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0118] The invention is further described by means of example but not in any limitative sense with reference to the accompanying drawings of which:

[0119] FIG. 1 shows a side elevation of a wheel in accordance with the invention;

[0120] FIG. 2 shows a plan view of the wheel shown in FIG. 1;

[0121] FIG. 3 shows an exploded view of the wheel shown in FIGS. 1 to 2;

[0122] FIG. 4 shows a side elevation and perspective view of the hub of the wheel shown in FIGS. 1 to 3;

[0123] FIG. 5 is an enlarged partial cross section of the hub shown in FIG. 4;

[0124] FIG. 6 shows four side views of the hub shaft and first hub member of the wheel;

[0125] FIGS. 7 and 8 are side views of the hub shaft and hub members showing the second hub member moving from a deployed position towards a collapsed position;

[0126] FIGS. 9 and 10 are cross sectional views of the hub shaft and hub member showing the second hub member moving towards the deployed position;

[0127] FIGS. 11 to 13 are side views showing successive stages of movement, following on from FIG. 8, showing the second hub member moving to a collapsed position;

[0128] FIGS. 14 to 15 are side views showing successive stages of movement, following on from FIG. 13, showing the third hub member moving from a deployed position to a collapsed position;

[0129] FIGS. 16 to 18 show use of the rim lock arrangement;

[0130] FIGS. 19 to 23 show successive steps in folding of the wheel shown in the preceding figures;

[0131] FIG. 24 is a side view of a bike comprising the wheels in accordance with the invention;

[0132] FIG. 25 shows a side view, rear view and perspective view of the bike shown in FIG. 24 in a folded configuration;

[0133] FIGS. 26 and 27 show views of an alternative hub of the present invention;

[0134] FIGS. 28 and 292 show views of a further alternative hub including a clamping arrangement; and

[0135] FIGS. 30 and 31 show an alternative rim section including a clamping arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0136] FIGS. 1 to 4 show a foldable bicycle wheel in accordance with this invention. The wheel comprises a hub (1), for example an internally geared hub (1) as is commonly known in the art. The hub (1) comprises a cylindrical hub shaft (2), a first hub member (3), a second hub member (4) and a third hub member (5). The first hub member (3) comprises a first collar member (6) secured to the hub shaft (2), the first collar member (6) extending from the first hub member (3). The second hub member (4) comprises a second collar member (7), and a circular ring (8). The third hub member (5) comprises a third collar member (9) and a circular ring (10). The first collar member (6), second collar member (7) and third collar member (9) collectively form a cylindrical collar (10).

[0137] Three rim sections (11, 12, 13) are connected to respective collar members (6, 7, 9) by pairs of tubular spoke members (14) connected to the rims by mountings (15).

[0138] Latch members (16, 17, 18) are slidably received in channels in the ends of the rim sections (11, 12, 13) respectively. One or more of the latch members (16, 17, 18) may be secured by locking members e.g. (19). One of latch members may be a fixed locking member.

[0139] A brake disc (20) and sprocket (21) with bearing (22) are mounted on the hub shaft (2).

[0140] The spoke members (14) are received in sockets (23) in each of the collar members (6, 7, 9). The sockets (23) may be circular slots.

[0141] FIG. 5 shows a cross sectional view of the hub (1). The arrangement is shown in plan view, from the edge of the wheel in FIG. 6. FIG. 5 is enlarged for clarity. The hub shaft (2) is connected to the first collar member (6) by a narrow connecting portion (25) to define engagement slots (26) on either side of the first collar member (6).

[0142] The second collar member (7) has a cylindrical channel (27) dimensioned to form a sliding fit with the hub shaft (2). Radially extending, axially parallel first (28) and second (29) engagement surfaces of the first collar member (6), abut the engagement surfaces of the second (7) and third (9) collar members, discussed below. The first engagement surface (28) abuts and engages a third engagement surface (30) of second collar member (7). The third collar member (9) extends between the first (6) and second (7) collar members to complete the enclosure of the collar (10). A fourth engagement surface (31) of second collar member (7) abuts and engages a fifth engagement surface (32) of the third collar member (9). A sixth engagement surface (33) of the third collar member (9), abuts and engages the second engagement surface (29) of the first collar member (6). Each engagement surface has a projection or recess to ensure that the engagement surfaces are securely coupled together in the deployed position of the wheel.

[0143] Projections (34, 35) of the third (30) and the sixth (33) engagement surfaces extend into the engagement slots (26) of the first collar member (6). Projections (34) and (35) extend over the surface of the hub shaft (2). This arrangement improves the contact between the second (7) and third (9) collar members and the hub shaft (2), reducing any liability for wear or damage in use. The projections (34) and (35) are cylindrical in radial cross section so that the projections (34) and (35) lie against the cylindrical surface of the hub shaft (2). When the second (7) or third (9) collar members are free to rotate then the projections (34) and (35) may be withdrawn rotationally from the sockets (23), to disengage the first (28), second (29), third (30) and sixth (33) engagement surfaces. Projection (37) extending from the fifth engagement surface (32) of the third collar member (9) is received into a recess (38) of the fourth engagement surface (31) of second collar member (7). The projection (37) has parallel planar sides (39) and the recess (38) has corresponding parallel planar sides (40). The close fit between the sides (39) of a projection (37) and the sides (40) of the recess (38) prevents rotation of the third collar member (9) relative to the second collar member (7), until one of the collar members has been slidably moved along the wheel axis to disengage the fourth engagement surface (31) from the fifth engagement surface (32).

[0144] Each of the sockets (23) are configured to receive ends of the spoke members (14) so that the collar members (6, 7, 9) can support their respective rim sections (11, 12, 13) as shown in FIG. 1.

[0145] FIG. 6(a)-(d) show four views of the hub shaft (2) and the first collar member (6). A first channel (41) has a first portion (42) extending parallel to the wheel axis and a circumferential portion (43) extending around the circumference of the hub shaft (2) at a constant location along the wheel axis. First (44) and second (45) locking apertures are located at either end of the first channel (41). The first (44) and second (45) locking apertures maybe located within the first channel (41) or located offset relative to the first channel (41). The first channel (41) has a constant radial depth so that a first locking member (46) or other projection may slide smoothly along the first channel (41) in use. The first locking aperture (44) has a greater radial depth to hold the first locking member (46) or the second collar member (7) in the fully deployed position. The second locking aperture (45) also with a greater radial depth is used to hold the second collar member (7) in the fully collapsed position.

[0146] A second channel (47) extends from the centre of the hub shaft (2). The second channel has a first helically extending portion (48a) extending helically around the circumference of the surface of the hub shaft (2) and a circumferentially extending portion (48b) extending around the circumference of the surface of the hub shaft (2) at a constant location on the wheel axis. Third (49) and fourth (50) locking apertures are located at either end of the second channel (47). The third (49) and fourth (50) locking apertures maybe located within the second channel (47) or located offset relative to the second channel (47). The second channel (47) has a constant radial depth so that a second locking member (51) or other projection may slide smoothly along the second channel (47) in use. The third locking aperture (49) has a greater radial depth to hold the second locking member (51) or the third collar member (9) in the fully deployed position. The fourth locking aperture (50) also with a greater radial depth is used to hold the third collar member (9) in the fully collapsed position.

[0147] The first locking member (46), for example a pin, comprises a head (52), shaft (53) and end (54) mounted in a threaded bore (55) in the second collar member (7) so that the end (54) of the first locking member (46) is received in the first locking aperture (44) provided in the hub shaft (2). Engagement of the first locking member (46) within the threaded bore (55) so that the end (54) is received in the first locking aperture (44) prevents unwanted movement of the second hub member (4) from the fully deployed position of the wheel, discussed below. Engagement of the first locking member (46) within the threaded bore (55) so that the end (54) is received in the second locking aperture (45) prevents unwanted movement of the second hub member (4) from the fully collapsed position of the wheel, discussed below.

[0148] The second locking member (51), for example a pin, comprises the same features as the first locking member (46) and mounted in a threaded bore (not shown) of the third collar member (9) so that the end of the second locking member (51) is received in the third locking aperture (49) provided in the hub shaft (2). Engagement of the second locking member (51) within the threaded bore of the third collar member (9) so that the end of the second locking member (51) is received in the third locking aperture (49) prevents unwanted movement of the third hub member (5) from the fully deployed position of the wheel, discussed below. Engagement of the second locking member (51) within the threaded bore of the third collar member (9) so that the end of the second locking member (51) is received in the fourth locking aperture (50) prevents unwanted movement of the third hub member (5) from the fully collapsed position of the wheel, discussed below.

[0149] In an embodiment, the hub shaft (2) may only include two of the locking apertures, as described above. For example, the hub shaft (2) may include the second locking aperture (45) and the fourth locking aperture (50). By way of further example, the hub shaft (2) may include the first locking aperture (44) and the third locking aperture (49).

[0150] In another embodiment the bores (55) may not be threaded. Biasing members, such as resilient springs, may be used to bias the first (46) and second (51) locking members towards the locking apertures (44, 45, 49, 50) so that each end (54) of the locking members (46, 51) is received in one of the locking apertures (44, 45, 49, 50).

[0151] FIG. 7 shows the hub members (3, 4, 5) in the deployed position in which the locking members (46, 51) are engaged so that the collar members (6, 7, 9) completely encase the hub shaft (2). In the deployed position the first locking member (46) is received in the first locking aperture (45), preventing movement of the second hub member (4).

[0152] When the first locking member (46) is released or unscrewed from the first locking aperture (44) so that the second collar member (9) is released from the second first aperture (44) the first locking member (46) is free to move in an axial direction along the first portion (42) of the first channel (41) allowing the second collar member (7) to be pulled parallel to the wheel access away from first (3) and third (5) hub members and first (6) and second (7) collar members (to the left as shown in FIGS. 8 and 11). This movement moves the two spoke members (14) located in the sockets (23) of the second collar member (7) and the corresponding rim section (12). In this way, the wheel segment glides along the hub axis (to the left as shown in FIGS. 8 and 11. The wheel sector may then be rotated with the first locking member (46) passing circumferentially around the circumferential portion (43) of the first channel (41) until an end stop position is reached (see FIG. 13). Here the first locking member (46) may be screwed downwardly to locate the end (54) of the first locking member (46) within the second locking aperture (45) of the hub shaft (2).

[0153] FIGS. 9 and 10 show movement of the second hub member (4) towards a fully deployed position. As the second hub member (4) moves towards the fully deployed position, the first locking member (46) is urged upwardly over an inclined ramp surface (56) so that the first locking member (46) is positioned above the first locking aperture (44) so that the first locking member (46) may be screwed downwardly into the first locking aperture (44). Alternatively, when a resilient spring is used, as described previously, the first locking member (46) is urged upwardly over an inclined ramp surface (56) so that the first locking member (46) upon moving off the ramp surface is urged downwardly into the first locking aperture by the resilient spring.

[0154] FIGS. 12 and 13 show successive stages of rotation of the second collar member (7) as the first locking member (46) moves circumferentially within the circumferentially extending portion (48) of the first channel (41). FIG. 14 shows the second collar member (7) is the fully collapsed position.

[0155] FIGS. 14 and 15 shows the movement of the third hub member (5) to the fully collapsed position. When the second locking member (51) is released or unscrewed from the third locking aperture (49) so that the third collar member (9) is released from the third locking aperture (49) the second locking member (51) is free to move in a helical direction with along the spiral circumferentially extending portion (48b) of the second channel (47). When the third hub member (5) reach the end of the spiral circumferentially extending portion (48b) the third hub member (5) may be rotated circumferentially with the second locking member (51) following the first portion (48a) of the second channel (47). This movement moves the two spoke members (14) located in the sockets (23) of the third collar member (7) and the corresponding rim section (13). In this way, the wheel segment helically glides spirally along the circumferentially extending portion (48b) of the second channel (47) in an opposite direction to the second hub member (4) (to the right as shown in FIGS. 14 and 15. The wheel sector may then be rotated with the second locking member (51) passing circumferentially around the first portion (48a) of the second channel (47) until an end stop position is reached (see FIG. 15). Here the second locking member (51) may be screwed downwardly to locate the end of the second locking member (46) within the fourth locking aperture (50) of the hub shaft (2).

[0156] FIGS. 16 to 18 illustrate the locking and unlocking of the rims. Adjacent rim sections (11) and (12) have annular channels which abut at (57) so that channels are continuous.

[0157] A latch member (16) is slidable along the channels and may be secured in locked or unlocked positions using a locking member (19) having a threaded shaft (58) and a locking end portion (59) which may be received in first (60) or second (61) apertures in the wall of the rim portion (11). A tyre portion (62) (63) are mounted on the outer circumference of the rim portion (11) and (12) to form a continuous tyre in the fully deployed position as shown in FIG. 20(a).

[0158] A window (64) in the side of the rim portion (11) provides a visual indication that the wheel is locked in the deployed position and may be used safely. The unlocked position in shown in FIGS. 16 and 17.

[0159] FIGS. 17 and 18 show the locked position in which the latch member (16) has been slidably moved so that it is received partially within each of the channels. The latch member (16) is secured using the locking member (19) with the locking end portion (59) received in the second aperture (61).

[0160] A latch member (17) is also located in the channels of adjacent rim sections (12) and (13) and is slidable and locked via a locking member (19) as described above. A fixed latch member (18) is also located in the channels of adjacent rim sections (13) and (11).

[0161] FIGS. 19 to 23 illustrate the successive stages in folding of the wheel from the deployed position to the fully collapsed position.

[0162] In FIGS. 19(a)-(c) the latch member (16) has been moved to the unlocked position (as described above) which allows the wheel sector comprising rim section (12), second hub member (4) and collar member (7) to be moved slidably moved axially along the first channel (41), as described above, so that the second hub member (4) is displayed axially from the first (3) and third (5) hub members as shown in FIG. 20(a)-(c).

[0163] In FIGS. 20(a)-(c) the second hub member (4) is rotated circumferentially (anticlockwise) along the first channel (41), as described above, so that the wheel sector including second hub member (4) are located side by side and in adjacent spaces in relation to the first rim section (11).

[0164] In FIGS. 21(a)-(c) and 22(a)-(c) the latch member (17) has been moved to the unlocked position (as described above) which allows the wheel sector comprising rim section (13), third hub member (5) and collar member (9) to be moved helically, as described above, along the second channel (47) in the opposite direction to the previous motion of the sector comprising the rim section (12), second hub member (4) and collar member (7).

[0165] In FIG. 23(a)-(c) the three rim sections (11) (12) (13) are located side by side in adjacent space relation in fully collapsed position of the wheel.

[0166] FIGS. 24 and 25 show a bike (65) comprising the foldable bicycle wheel as described above. The frame of the bike (65) comprises a first hinge (66) located on a top tube (67) and a second hinge (68) located on a bottom tube (69). The first and second hinges (66, 68) are located along a vertical plane. The frame is pivotably moveable about the first (66) and second (68) hinges from a riding configuration, as shown in FIG. 25, to folded configuration, as shown in FIG. 26. In the riding configuration releasable locking means are provided to maintain the bike in the riding configuration by preventing pivotable movement about the hinges (66, 68). A further locking means may be provided to maintain the bike (65) in the folded configuration. In the folded configuration the handles bars of the bike (65) are located adjacent the seat. If both wheels of the bike (65) are in the fully collapsed position then the rim sections (11, 12, 13) of each wheel may be positioned adjacent a seat tube (70) with each set of rim sections on opposing side of the seat tube (70). Each brake disc (20) includes a brake disc guard (71) with one or more wheels (72), for example caster wheels, depending from each brake disc guard. A bottom bracket (73) includes a stand (74), such as a peg leg stand. In use the wheels (72) and stand (74) allow the bike to freestanding when in the folded configuration. A user may hold the bike, for example by the seat or handle bars, and pull the bike along on the wheels (72).

[0167] Each rim section of a wheel in accordance with this invention comprises a separate tyre section. Each tyre section may be composed of solid elastomeric material encasing an inflatable inner tube section. Each tyre section may have a valve which extends through the corresponding rim section. The ends of each of the tyre sections may be configured to compress against each other when the wheel is in the fully deployed position so that the tyre sections form a substantially continuous tyre surface. The tyre sections may be tubular, clincher or tubeless in design as is common practice.

[0168] FIGS. 26 and 27 show a further embodiment of the hub (100) for use in the wheel as described above. The hub may be an internally geared hub (100) as is commonly known in the art. The hub (100) comprises a cylindrical hub shaft (200), a first hub member (300), a second hub member (400) and a third hub member (500). The first hub member (300) comprises a first collar member (600) secured to a first cylindrical shell casing (7800). The second hub member (400) comprises a second collar member (700) attached to an outer circumference of a circular ring (800). The third hub member (500) comprises a third collar member (900) attached to an outer circumference of a circular ring (1000). The first collar member (600), second collar member (700) and third collar member (900) collectively form a cylindrical collar (1000). The hub (100) further comprises a second cylindrical shell casing (7900). Both the first (7800) and second (7900) cylindrical shell casings are attached to the hub (100) via an attachment means, for example screws (8000) at both ends of the hub (100), to form a single cylindrical enclosure enclosing the cylindrical hub shaft (200). The hub (100) further comprises a pin (8100) extending longitudinally through the centre of the hub (100). The pin (8100) is connected to the gears of the hub (100) as is commonly known in the art.

[0169] FIGS. 28 and 29 show a hub including a clamping arrangement for clamping the collars in the deployed position of the wheel.

[0170] FIG. 28 shows a hub in the deployed configuration of the wheel. A hub shaft (101), as second (102), and third (103) collar members interlocked with the third collar member (109), which is fixed to the hub shaft (101). A clamping member comprises a cam surface (105), mounted on a transverse shaft (106), and having a cam lever (110). The cam surface (105), has a variable radius from the transverse axis (106), so that a variable clamping force is applied to contact member (107). The contact member (107) is slidably mounted upon shaft (108) so that the clamping force is applied to both second and third collar members (102) (103) as the clamping member (110) and cam surface (105) are rotated by a user. A bearing (104) comprises a low friction polymeric material. A cylindrical sleeve manufactured by lgus may be employed.

[0171] FIGS. 29 and 30 illustrate a rim clamping arrangement for securing adjacent rim sections in the deployed position of the wheel. The rim section (200) has an annular channel in which a slidable latch member (201) is slidable between locked and unlocked positions within the channel. A rim clamping member comprises a clamping plate (202) extending circumferentially in contact with the radially, inwardly-facing surface (203) of the rim (200). The clamping plate (202) has a circumferential concave channel (204) configured to slide over the corresponding convex surface of the radially, inwardly-facing rim surface (203). The clamping plate (202) is radially movable upon a projection (not shown) extending radially inwardly from a proximal engagement with the radially inner surface of sliding member (201) having a distal radially innermost portion upon which a transverse pivot pin (205) and cam member (206) are rotatably mounted. The radius of the cam surface (208) of the cam member (206) is dependent on angular location of the cam member so that raising or lowering of the cam lever (207) exerts a variable clamping force on the clamping member (202) to secure the clamping member (202) and sliding member (201) in relation to the rim (200). In the configuration shown in FIG. 33, two adjacent rim members may be secured together to prevent movement thereof during use of the wheel.