[001] The present invention generally relates to bicycles, and more particularly to a folding bicycle and/or a collapsible bicycle frame.

Background

[002] There have been many attempts at producing folding bicycles that have collapsible frames. Many known folding bicycles are not convenient to fold or collapse, are unwieldy, unsafe or difficult to ride. Some known folding bicycles can also be relatively costly to manufacture.

[003] For example, US 3,623,749 discloses a portable bicycle having a seat assembly pivotally affixed to a bottom assembly, and a clamp joining the bottom assembly and a front wheel assembly permitting the front wheel assembly to be removably attached. This portable bicycle does not collapse in a vertical plane thereby leaving the collapsed bicycle relatively bulky. [004] US 4,895,386 discloses a bicycle with a collapsible frame having front and rear frame posts and cross-beams interconnecting the front and rear frame posts. A cross-beam of the frame is a two-part cross-beam, the parts of which are articulated. The two-parts of the cross-beam can be pivoted towards the front and rear frame posts. The structural integrity of the collapsible frame is questionable in view of the quadrilateral type frame structure without any diagonal supports.

[005] US 5,785,338 discloses a collapsible bicycle with a main frame that has front frame and rear frame sections. The front frame and the rear frame are pivotally connected. Again, the structural integrity of the frame could be questioned as it would appear significant torsional forces could be experienced in the front frame in the vicinity of reinforcing plate 15 or in the vicinity of the head tube.

[006] Structural integrity is an important consideration in the design of folding bicycles. In standard bicycles a commonly used frame is the diamond type frame, which is believed to provide a relatively strong structural frame arising from the basic engineering principle of the truss. A diamond type frame maintains shape without needing to rely on any angular strength or reinforcing members at the joints to retain the angle between each frame member. A truss is a structure comprising one or more triangular units. In a diamond type frame for a standard bicycle, a main triangle consists of a head tube, a top tube, a down tube and a seat tube. A rear triangle consists of the seat tube, and paired chain stays and seat stays. The top tube connects the head tube to the seat tube near the top, and the down tube connects the head tube to a bottom bracket, near the base of the seat tube, that supports a crankset.

[007] The Applicant is unaware of any folding bicycle or collapsible bicycle frame that makes use of the structural integrity of a diamond type frame.

[008] There is a need for a folding bicycle and or a collapsible bicycle frame which addresses or at least ameliorates one or more problems inherent in the prior art.

[009] The reference in this specification to any prior publication (or information derived from the prior publication), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that the prior publication (or information derived from the prior publication) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Brief Summary

[010] In a broad form, an embodiment of the present invention provides a folding bicycle and/or a collapsible diamond type bicycle frame.

[01 1] In a preferred form, a diamond type bicycle frame is utilised for structural integrity and to enable use of hinged, rotatable, pivotal, or the like, frame connection points. This advantageously allows the frame to be folded such that frame members are stacked, yet the structural benefits of the diamond type frame are retained when the folding bicycle is being ridden. In one example, a plurality of frame members can be stacked substantially parallel or adjacent when folded. [012] According to a first aspect, there is provided a diamond type frame for a folding bicycle, comprising a slide able to move along at least part of a seat tube. A top tube is pivotally joined to the slide, the top tube able to move towards a down tube. Seat stays are pivotally joined to the slide, the seat stays able to move towards chain stays. The down tube and the chain stays are pivotally joined to a base section, wherein the slide is able to be moved towards the base section to collapse the diamond type frame.

[013] Preferably, a bottom bracket for supporting a crankset is positioned at a point suitable for the posture of a rider, which may be, but is not necessarily, at the base of the seat tube. In one non-limiting example, the bottom bracket can be positioned along the chain stays and behind the base section of the seat tube towards a rear wheel position.

[014] In other particular, but non-limiting, forms: the seat stays are dual seat stays including two separated elongate members joined to opposite sides of the slide; the slide is a ring clamp; and/or the top tube is pivotally joined to a first side of the slide and the seat stays are pivotally joined to a second side of the slide. The ratio of the length of the chain stays to the seat stays can be varied, so as to allow different embodiments of the diamond frame to fold. In non-limiting examples, the chain stays may be longer in length than the seat stays, or may be approximately equal in length.

[015] According to yet further optional aspects, provided by way of example only: a head locking member is positioned about or integrated with a head tube; the top tube is pivotally joined to the head locking member; the down tube is pivotally joined to the head locking member; the down tube is releasably lockable in position relative to the head locking member; and/or, a pin or bolt passes through the head locking member and the down tube to lock the down tube in position.

[016] In other particular example embodiments: the base section of the seat tube is fixed to or integrated as part of the seat tube; the base section of the seat tube is part of the seat tube; the down tube is pivotally joined to a first side of the base section and the chain stays are pivotally joined to a second side of the base section; the down tube and the chain stays are joined at a common pivot point on the base section of the seat tube; and/or, the seat stays form a single seat stay section pivotally joined to the slide.

[017] Optionally, there is also provided collapsible handlebars, folding and/or rotating cranks, and/or a rotatable seat fixed to a seat post that is received within the seat tube.

[018] According to a second aspect, there is provided a collapsible diamond type frame for a folding bicycle, comprising a top tube pivotally attached to a member engaging a seat tube. Seat stays are pivotally attached to the member, and a down tube and chain stays are attached to a base section and able to rotate relative to each other. At least part of the top tube is able to rotate towards the down tube, and at least part of the seat stays are able to rotate towards the chain stays so as to collapse the diamond type frame.

[019] In another particular example embodiment the down tube is able to rotate relative to the chain stays to further collapse the diamond type frame.

Brief Description Of Figures

[020] Example embodiments should become apparent from the following description, which is given by way of example only, of at least one preferred but non-limiting embodiment, described in connection with the accompanying figures.

[021] Figure 1 illustrates a perspective view of an example embodiment of a folding bicycle when fully expanded and ready to be ridden; [022] Figure 2 illustrates a side view of the example folding bicycle illustrated in Figure 1;

[023] Figure 3 illustrates a side view of the example folding bicycle in a first partially folded position;

[024] Figure 4 illustrates a side view of the example folding bicycle in a second partially folded position; [025] Figure 5 illustrates a side view of the example folding bicycle in a completely folded position;

[026] Figure 6 illustrates a side view of another example folding bicycle;

[027] Figure 7 illustrates a side view of the example folding bicycle shown in Figure 6 when in a completely folded position;

[028] Figure 8 illustrates side views of an example rear hinged seat;

[029] Figure 9 illustrates side views of an example front hinged seat;

[030] Figure 10 illustrates a front view of example folding handle bars when in a usable position and also when in a folded position;

[031] Figure 1 1 illustrates perspective views of an example rotating crank, when in a usable position and also when in a rotated position;

[032] Figure 12 illustrates perspective views of an example folding crank, when in a usable position and also when able to be folded;

[033] Figure 13 illustrates a side view of a further example folding bicycle when in a fully expanded position and ready to be ridden, and also in a completely folded position; [034] Figures 14-17 illustrate side views of another example diamond type frame for a folding bicycle;

[035] Figures 18-20 illustrate side views of another example diamond type frame for a folding bicycle. Preferred Embodiments

[036] The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

[037] In the figures, incorporated to illustrate features of example embodiments, like reference numerals are used to identify like parts throughout the figures.

[038] Referring to Figures 1 and 2 there is illustrated a folding bicycle in a fiilly expanded position when the bicycle is ready to be ridden. The folding bicycle 10 includes a diamond type frame 12. A slide 14 is able to move along at least part of the length of a seat tube 16. In one example form, slide 14 is releasably attachable to seat tube 16. A top tube 18 (which can be one or more separate tubes) is pivotally joined to slide 14. Top tube 18 is able to move towards a down tube 20 when slide 14 is released. Seat stays 22 are pivotally joined to slide 14. Seat stays 22 are able to move towards chain stays 24 when slide 14 is released. Down tube 20 is pivotally joined to a base section 26, that is part of or attached to seat tube 16. Slide 14 is releasable from seat tube 16 to enable slide 14 to be moved towards base section 26 or a lower portion of seat tube 16 so as to collapse the diamond type frame 12.

[039] In one form slide 14, that is fixable to and in sliding engagement with seat tube 16, is a ring, cylinder, ring clamp or other type of circular or annular clamp able to be held or fixed to seat tube 16. A variety of clamping or engagement mechanisms are possible. For example, a clamp lever may tighten slide 14, for example a type of ring clamp, about seat tube 16. Additional holding mechanisms can be provided to help secure slide 14 to seat tube 16. For example, a flange or other type of protrusion(s) can be provided about seat tube 16 to assist with engagement and holding of slide 14 when clamped, tightened or fixed to seat tube 16. The extent of any such flange or protrusions could be limited so as to provide secure holding when slide 14 is tightened, but to also allow slide 14 to easily pass over any such flange or protrusion(s) when slide 14 is released. In another additional or alternate form, a locking pin or the like can be associated with slide 14 and seat tube 16 to fix, or assist in fixing, slide 14 to seat tube 16. Such a locking pin could pass below slide 14 and through seat tube 16, or through both slide 14 and seat tube 16. In an alternate form, a slide could be provided to be internal, or partially internal, to seat tube 16.

[040] Top tube 18 is hinged or pivotally joined (or by other rotatable engagement means) to a first side 14a of slide 14, and seat stays 22 are hinged or pivotally joined (or otherwise rotatable and engaged with) a second side 14b of slide 14. In an alternate version, top tube 12 and seat stays 22 could be joined at a common pivot axis provided as part of slide 14.

[041] In one non-limiting example, chain stays 24 are longer in length than seat stays 22. Also, again according to a non-limiting form, a bottom bracket 28 for supporting a crankset 30 is positioned along chain stays 24 and behind base section 26 towards a rear wheel position. In other forms, the bottom bracket can be located at other positions, for example at the base area of seat tube 16. [042] Seat stays 22 can be different types of seat stays, for example dual seat stays or single seat stays. In Figure 1, dual seat stays 22 are illustrated that include two separated elongate members 22a, 22b joined to opposite sides of slide 14. In an alternate form, the seat stays can form a single seat stay section by being formed into a single section that is hinged or pivotally joined to slide 14.

[043] A head member 32 is provided that is positioned about, or integrated with, a head tube 34. In one example form, head member 32 is able to be fixed in position thus providing a head locking member. Top tube 18 is hinged or pivotally joined to head locking member 32. Also, down tube 20 is hinged or pivotally joined to head locking member 32. As illustrated, top tube 18 and down tube 20 have separate pivot axes on head locking member 32. In an alternate form, top tube 18 and down tube 20 could have a common pivot axis as part of head locking member 32. Also alternately, an embodiment can be provided having only head tube 34 without distinct head locking member 32. In this fonn, top tube 18 and down tube 20 could be directly hinged, pivotally joined or attached to head tube 34 at different pivot axes or at a common pivot axis on head tube 34.

[044] In the example embodiment illustrated, down tube 20 is releasably lockable in position relative to head locking member 32. A pin 36, or bolt or the like, passes through head locking member 32 and down tube 20 so as to lock down tube 20 in position relative to head locking member 32. A variety of locking mechanisms can be used, one example of which is pin 36 that passes through down tube 20 and is secured in position. In one example, pin 36 may be provided with a folding or rotatable end section to ensure pin 36 is secured and does not fall out while the bicycle is being ridden. Alternatively, pin 36 could be provided with a thread onto which a locking lever or nut, such as a form of wing nut or rotating threaded lever, could be threaded.

[045] Base section 26 is optionally part of or fixed to seat tube 16. Base section 26 could be welded to seat tube 16 or integrally formed as part of seat tube 16. Base section 26 can be in the form of a bracket or a type of winged plate. In an alternate embodiment, there need not be provided a distinct base section 26. For example, down tube 20 and/or chain stays 24 could be directly hinged or pivotally attached to seat tube 16 at a lower or base section of seat tube 16. Down tube 20 and chain stays 24 could be attached to a section of the seat tube 16 at separate pivot axes or at a common pivot axis. Additionally, it should be noted that a variety of configurations of base section 26 could be utilised to achieve the desired effect of allowing rotation of seat tube 16 towards chain stays 24 and also rotation of down tube 20 towards chain stays 24. [046] In the example illustrated, down tube 20 is hinged or pivotally joined to a first side 26a of base section 26, and chain stays 24 are hinged or pivotally joined to a second side 26b of base section 26.

[047] Also provided as part of folding bicycle 10 are, for example, front forks 40, handle bars 42, seat post 44, seat 46, front wheel 48, rear wheel 50, pedals 52, crankarms (i.e. cranks) 54 and chain 56.

[048] Thus, there is provided, in the example form illustrated, a collapsible diamond type frame 12 for a folding bicycle 10. Frame 12 includes slide 14 fixable to and in sliding engagement with seat tube 16. Slide 14 is hinged or pivotally attached to top tube 18 and seat stays 22. Top tube 14 is able to rotate relative to down tube 20 and seat stays 22 are able to rotate relative to chain stays 24. Slide 14 is releasable from seat tube 16 to enable slide 14 to be moved towards base section 26 of seat tube 16 so as to collapse the diamond type frame 12. Down tube 20 is also able to rotate relative to chain stays 24 to further collapse the diamond type frame 12.

[049] Head locking member 32 provides a frame locking mechanism which locks the angle of the head tube 34 / goose neck to down tube 20, thus keeping frame 12 rigid and preventing frame 12 from folding whilst being ridden. Slide 14 provides a mechanical connection, such as in the form of an articulated arm joint, between top tube 18 and seat stays 22. Slide 14 is preferably captured in a mechanical stop at or near the top of seat tube 16.

[050] Seat 46 is preferably hinged and can lift upwardly, from the front section or rear section of seat 46, so as to provide clearance from rear wheel 50 when frame 12 is completely folded. Handle bars 42 are preferably able to be folded and include a horizontal member able to split to fold substantially parallel to the vertical stocks. Various crankarms 54 may be provided that are able to be rotated or folded to assist in reducing the size of the bicycle when in a collapsed form. Whilst folding, rotating or otherwise collapsing the crankarms/pedals is not necessary in order to fold the frame, this can reduce the folded size of the bicycle. An advantage is that by reducing the extent of protrusion of pedals, then normal or standard pedals can be fitted including those that support toe clips.

[051] In one example as illustrated, base section 26, at the bottom of seat tube 16, is set forward from a standard or traditional bicycle position for a bottom bracket holding a crankset. In the example illustrated, as opposed to a standard bicycle configuration, bottom bracket 28 is, optionally, attached to, or held by, and positioned along chain stays 24 rearwards of base section 26.

[052] Referring to Figure 3, bicycle 10 is shown in a first partially folded position. Front forks 40 and handle bars 42 are rotated 180° allowing the lead-in of front wheel 48 to be used to make the final collapsed form more compact. Head locking member 32 on or about head tube 34 is released and slide 14 moved part way down seat tube 16, thereby elongating the diamond type frame 12. Seat 46 has been lifted upwards at the front rotating around a hinge at the rear of seat 46, until seat 46 is substantially parallel to seat post 44. Seat post 44 can be rotated 90° within seat tube 16 to bring seat 46 into a position ready to fold beside rear wheel 50.

[053] Referring to Figure 4, slide 14 has been moved nearly all of the way to base section 26 of seat tube 16. At this point, frame 12 begins to fold back onto itself. Seat 46 and seat post 44 have been lowered into seat tube 16 and cross members of handle bars 42 have been split into two sections and folded parallel to the handle posts.

[054] Referring to Figure 5, bicycle 10 is illustrated as being in a completely folded position, for example ready for transport or storage. In a further example, a latch or magnets can be used to hold bicycle 10 in a closed position.

[055] Figures 6 and 7 illustrate an alternate embodiment showing a bicycle in a fully expanded and fully collapsed position, respectively. A larger front wheel 60 is fitted to , front drop out 62. A shorter front fork 41 can also be utilised. Front wheel 60 can be provided with a standard quick release mechanism to easily remove front wheel 60 from front drop out 62 to produce a very small folded package of frame 12 without needing to remove rear wheel 50 or having the complication of freeing the rear wheel cog from the chain.

[056] Figure 8 illustrates a side view of an example seat 46 attached to seat post 44. Hinge 45 is provided near a rear section of seat 46 to allow seat 46 to rotate upwardly relative to seat post 44. Figure 9 illustrates a side view of seat 46 attached to seat post 44. Hinge 45 is provided near a front section of seat 46 to allow seat 46 to rotate upwardly relative to seat post 44. This upward movement, whether hinged near a front or rear section of seat 46, allows seat 46 to clear rear wheel 50 when folded. A friction hinge or a snap clip can be used to secure seat 46 in the riding position. Once seat 46 is rotated into the vertical position, seat post 44 is then released using a conventional clamp and rotated 90° to place the seat in a position required to allow seat 46 to be retained on the bicycle whilst in a folded position.

[057] Figure 10 illustrates an example arrangement for a folding set of handle bars 42 that, when folded, pass on either side of rear wheel 50. A simple clamp 70 engaging with pin or protrusion 71 can be used to hold the two horizontal halves of the handle bars 42 firmly in place when in operation. When clamp 70 is released from pin or protrusion 71 then hinges 72, 74 allow the two horizontal halves to be folded as illustrated. [058] Figure 1 1 illustrates perspective views of an example rotating pedal crank 80, when in a usable position and also when in a rotated position. Crank 80 is in two sections, first section 82 and second section 84 which is able to be rotated through 90 degrees along the crank axis. This rotation is limited by lugs or stops, preferably provided at or near a join mechanism 88 that links first section 82 and second section 84 of crank 80. Slide 86 covers join mechanism 88 when crank 80 is in normal use. In one example, slide 86 can be tapered to fit the shape of a crank, and/or spring loaded so that slide 86 is held in position over join mechanism 88 which also holds crank 80 in a normal working position. Moving slide 86, which in the illustrated example is towards pedal 52 as crank 80 tapers towards pedal 52, releases join mechanism 88 and allows second section 84 to be rotated 90 degrees. This assists in reducing the size of the bicycle when collapsed. The rotation direction is preferably against the direction of pedalling, so that when in use a rider pushing on pedal 52 acts to keep pedal 52 in the correct position for use. A variety of join mechanisms 88 that allow rotation of second section 84 can be provided, for example a pin or bolt oriented along an axis of crank 80.

[059] Figure 12 illustrates perspective views of an example folding pedal crank 90, when in a usable position and also when able to be folded. Crank 90 is in two sections, first section 92 and second section 94 which is able to be folded 180 degrees. Hinge mechanism 98 links first section 92 and second section 94 of crank 90. Slide 96 at least partially covers and holds first section 92 and second section 94 together, preventing rotation relative to each other about hinge mechanism 98, when crank 90 is in normal use. In one example, slide 96 can be tapered to fit the shape of a crank, and/or spring loaded so that slide 96 is held in position at least partially over first section 92 which also holds crank 90 in a normal working position. Moving slide 96, which in the illustrated example is towards pedal 52 as crank 90 tapers towards pedal 52, releases first section 92 so that second section 94 can rotate about hinge mechanism 98 and allows second section 94 to be folded 180 degrees. This assists in reducing the size of the bicycle when collapsed. Preferably, hinge mechanism 98 is a vertical hinge located near where a traditional cotter pin used to be located. Second section 94 can be folded 180 degrees to allow pedal 52 to be stored protruding inwards towards the bicycle frame, as opposed to the normal riding position where pedal 52 protrudes outwards from the bicycle frame. A variety of hinge mechanisms 98 that allow folding of second section 94 can be provided, for example a pin or bolt oriented perpendicular to the axis of crank 90.

[060] Figure 13 illustrates a folding bicycle with shorter front forks 41 and chain stays 25. In this configuration the bicycle is provided with a larger front wheel 60 and a larger rear wheel 61. Front wheel 60 can be removed from front drop out 62, and rear wheel 61 can be removed from rear drop out 64 when the bicycle is to be collapsed. With the wheels 60, 61 removed the frame 12 in a fully folded position is even more compact as the front forks 41 and chain stays 25 are shorter in this arrangement than when using smaller wheel types. Advantageously, in this form when using larger wheels 60, 61 the folding bicycle has the appearance of a regular fixed frame bicycle.

[061] Thus, a folding bicycle has been provided that is able to be folded without the use of any special tools or the need to disconnect any frame member, or necessarily remove any component from the bicycle. Each main frame member is joined to corresponding main frame members via a horizontal hinge or pivot arrangement. A variety of hinges or pivots could be used, for example pin and socket or hole arrangements, bolt and nut arrangements, stud arrangements through holes joining plates, or a variety of other mechanical arrangements. The hinges or pivot arrangements transmit a twisting torque from the front of the bicycle frame to the rear of the bicycle frame, but allow the diamond truss arrangement to be collapsed in the vertical plane. In an optional example, a single front clamp could be utilised and released to allow the frame to collapse.

[062] In various forms, the top tube and seat stays connect together at or near the seat tube via a slide mechanism that traverses the seat tube. The five main members of the diamond type frame, along with the front forks, are brought together by sliding this slide connection down the seat tube to the bottom bracket. This action temporarily elongates the diamond type frame. As the slide passes the mid-point, however, the top side of the diamond type frame becomes inverted and the frame then begins to fold around the hinge points at the base section of the seat tube, thereby bringing the main members of the frame together in a parallel stack.

[063] The down tube and the top tube are joined to a head tube assembly or fixture, preferably, though not necessarily, using separate hinge points that are a small distance apart. The head tube assembly is clamped onto, or otherwise releasably fixed to, the down tube when the bicycle is unfolded in a riding position. In conjunction with the small distance between these two hinge points, this holds the bicycle frame rigid. When the clamp is released the head tube assembly can "rock" forward, thus releasing the truss structure and allowing the frame to fold.

[064] In a particular, but optional, example, in order to facilitate or assist the slide to continue down past the mid-point of the seat tube to the base section, the chain stays can be made to be longer than the seat stays. In one example form, this is achieved by locating the base section of the seat tube slightly forward of the bottom bracket such that the seat tube joins the lower part of the frame forward of the axis of rotation of the crankset.

[065] The bottom bracket or pedal crankset axis is thus positioned along the chain stays. This means that the distance between the crankset axis and the rear wheel cog does not alter when the frame is folded, thus leaving the drive chain in place. The seat stays are preferably, but not necessarily, narrower than the chain stays and are hinged in-board so that upon folding the seat stays fall inside the line of the chain drive. The right chain stay passes through the looped chain in a conventional manner. [066] Using an appropriate seat, folding handle bars and small diameter wheels, the folding bicycle can be folded into a very compact form that is generally linear in dimension making it suitable for transport in the boot of a car or storage in a cupboard. The folded bicycle is also of a shape and size that makes it easier to carry by a pedestrian or on public transport. However, the frame provides the feel of a regular bicycle when ridden. When the bicycle is in a folded form the wheels of the bicycle are at the extremities of the folded package, allowing the folded bicycle to be towed or pushed like a wheelbarrow when being transported by a pedestrian. [067] In an alternate embodiment, the bicycle can utilise larger diameter wheels, for example with quick release hubs, that creates a more conventional bicycle when in the expanded form, yet which can be made very compact for transport by removing the wheels and then folding the frame.

[068] The folding bicycle uses a standard chain drive for propulsion. When fitted with a small diameter rear wheel, a low number tooth cog at the rear can be used in combination with a moderate diameter chain ring on the pedal crank to give a sensible gearing. A suitable combination for a 300 mm diameter rear wheel being a 38 or 42 tooth chain ring to a 9 or 10 tooth rear cog. This produces a gearing ratio for a sensible cadence. A wide variety of other gearing combinations can be used to suit rider requirements.

[069] A small diameter rear wheel dictates the use of hub gears, or a hub gear/coaster brake combination when a bicycle with gears is desired. Alternatively, or in addition, gearing may be fitted into the bottom bracket. In the case where larger diameter wheels are used, derailleur gears optionally can be used. Conventional calliper or disc brakes can be fitted or a coaster brake may be used. A Bowden cable for a front brake may be routed through a hollow bolt in the gooseneck. If a coaster brake is fitted at the rear of the bicycle, this then retains the ability to spin the steering mechanism through 360°. Folding pedals fitted to conventional pedal cranks can further reduce the spatial extent of the folded form of the bicycle.

[070] Figures 14-17 illustrate side views of an alternate example diamond type frame 100 for a folding bicycle. Figure 14 illustrates frame 100 in an expanded or usable position. Frame 100 includes slide 1 14 (i.e. a moveable member), that if preferred can be releasably attachable to seat tube 116. Top tube 108 is pivotally joined to slide 114. Top tube 108 is able to move generally towards down tube 120 when slide 1 14 is moved in a downward direction. Seat stays 122 (which may be single or double seat stays near slide 1 14) are pivotally joined to slide 114. In one example top tube 108 and seat stays 122 are pivotally joined to slide 1 14 at a common pivot axis. Seat stays 122 are able to move generally towards chain stays 124 when slide 1 14 is moved in a downward direction. Down tube 120 is pivotally joined to bracket 128 (i.e. in this form a base section of seat tube 1 16) for supporting pedal crankarms. In one form, slide 1 14 is able to be mechanically released from seat tube 1 16 to enable slide 1 14 to be moved towards bracket 128 (i.e. base section) so as to collapse diamond type frame 100.

[071] In one form, slide 1 14 is a ring, cylinder, ring clamp or other type of circular or annular clamp able to be held or fixed to seat tube 1 16. A variety of clamping or engagement mechanisms are possible and include mechanisms hereinbefore mentioned. For example, a bolt or pin may pass through a section of slide 1 14, which might also pass through seat tube 1 16 so as to hold slide 114 to ensure frame 100 is kept in an open or expanded position. Top tube 108 and seat stays 122 are able to rotate with respect to each other about a horizontal axis of slide 114.

[072] A head member 132 is provided that is positioned about, or integrated with, a head tube that receives and holds forks 140. Head member 132 is provided with groove 137 that receives a pin or bolt provided at an end of arm 135. Top tube 108 is hinged or pivotally joined to head member 132. Arm 135 is hinged or pivotally joined to down tube 120. An end of arm 135 is also able to move in a constrained manner along groove 137, which in one optional example may only be possible after release of a locking mechanism, such as a pin or bolt, although this is not essential. [073] Referring to Figure 15, frame 100 is shown in a partially collapsed state where slide 1 14 has been moved towards bracket 128. This movement of slide 114 in a generally downwards motion can be facilitated by "rocking" of head member 132 so that forks 140 move towards down tube 120 and an end of arm 135 moves along groove 137. This play of movement provided by head member 132 enables top tube 108 to move towards down tube 120.

[074] Referring to Figure 16, frame 100 is illustrated in a further collapsed state where slide 1 14 is adjacent to, or partially overlaps, bracket 128. Down tube 120 and chain stays 124 are then able to rotate generally inwards towards seat tube 1 16. Down tube 120 and chain stays 124 rotate about a horizontal axis of bracket 128. Referring to Figure 17, frame 100 is illustrated in a fully collapsed or folded position. [075] Thus, in various forms there is provided, a diamond type frame 12, 100 for a folding bicycle, including a slide 14, 1 14 able to move along at least part of a seat tube 16, 1 16. A top tube 18, 108 is pivotally joined to the slide 14, 114, the top tube 18, 108 able to move towards a down tube 20, 120. Seat stays 22, 122 are pivotally joined to the slide 14, 1 14, the seat stays 22, 122 able to move towards chain stays 24, 124. The down tube 20, 120 and the chain stays 24, 124 are pivotally joined to a base section 26, 128, wherein the slide 14, 1 14 is able to be moved towards the base section 26, 128 to collapse the diamond type frame 12, 100. [076] Figures 18-20 illustrate side views of an alternate example diamond type frame 200 for a folding bicycle. Components of frame 200 are similar or the same as discussed for frame 100, other than a different form of top tube 208, seat stays 222 and member 214 which replaces a slide. In frame 200, member 214 is fixed in position relative to seat tube 116. Member 214 may include a pin, bolt or the like. Top tube 208 is hinged at a point along its length so that first section 208a and second section 208b are pivotally joined and can collapse and fold against each other. Similarly, seat stays 222 are hinged at a point(s) along its length so that first section 222a and 222b are pivotally joined and can collapse and fold against each other. In frame 200, a slide is not provided and instead second section 208b of top tube 208 and first section 222a of seat stays 222 are connected by member 214 to seat tube 1 16 and are able to rotate relative to seat tube 116.

[077] Referring to Figure 19, frame 200 is illustrated in a partially collapsed or folded position. Top tube 208 is collapsed and seat stays 222 are collapsed so that down tube 120 and chain stays 124 are able to move generally towards seat tube 1 16. Figure 20 illustrates frame 200 in a fully collapsed or folded position.

[078] Thus, in various forms there is provided, a collapsible diamond type frame 12, 100, 200 for a folding bicycle, comprising a top tube 18, 108, 208 pivotally attached to a member 14, 1 14, 214 engaging a seat tube 16, 1 16. Seat stays 22, 122, 222 are pivotally attached to member 14, 1 14, 214 (i.e. a slide member or a fixed member) engaging seat tube 16, 116, and a down tube 20, 120 and chain stays 24, 124 are attached to a base section 26, 128 and able to rotate relative to each other. At least part of the top tube 18, 108, 208 is able to rotate towards the down tube 20, 120, and at least part of the seat stays 22, 122, 222 are able to rotate towards the chain stays 24, 124 so as to collapse the diamond type frame 12, 100, 200.

[079] Components of the bicycle can be manufactured from conventional materials used in standard bicycle construction. For example, the frame members can be manufactured from steel, aluminium, carbon fibre or combinations thereof.

[080] Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. [081] Although a preferred embodiment has been described in detail, it should be understood that many modifications, changes, substitutions or alterations will be apparent to those skilled in the art without departing from the scope of the present invention.

[082] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.