GB2569085A

GB2569085A - Folding bicycle steering lock

Info

Publication number: GB2569085A
Application number: GB1712610.3A
Authority: GB
Inventors: Kalogroulis Alexander; Gerald Lambert Stuart
Original assignee: CROSSHEAD Ltd
Current assignee: CROSSHEAD Ltd
Priority date: 2017-08-06
Filing date: 2017-08-06
Publication date: 2019-06-12
Anticipated expiration: 2037-08-06
Also published as: GB201712610D0; GB2569085B

Abstract

A steering lock for a folding bicycle comprises a head tube casting 10, a steering tube 13 which passes through the head tube casting and rotates about steering axis 40, a steering clamp 9 which clamps to the steering tube 13 and an upper steering casting 8 which pivots about steering hinge pin 14. The head tube casting has an inner locking protrusion 30, while the upper steering casting 8 has an outer locking protrusion 32. When the upper steering casting is rotated about the steering hinge pin, and the steering clamp casting is rotated about the steering axis, the two locking protrusions are brought together. Alternatively there may be two outer locking protrusions 32, and the inner protrusion 30 is positioned between them.

Description

Field of the Invention

This invention relates to improvements in folding bicycles.

Background Art

GB2475793A (Lambert) discloses a folding bicycle that folds in stages, comprising a steering hinge pin that allows the upper steering assembly to be folded by bringing the handlebar assembly down to lie flat against the front wheel, a main hinge pin in the main frame assembly that allows the front wheel assembly, with upper steering assembly and handlebar assembly, to be pivoted to a position alongside the main frame assembly and a rear swingarm assembly, which is pivoted on two axes, that can be swung from an operative position to a folded position in which the rear wheel lies alongside the main frame on the opposite side to the front fork assembly.

Although this provides a compact arrangement, the front wheel assembly, steering assembly and handlebars are awkward and difficult to control as they are free to flop side to side as they pivot on the main steering axis within the head set casting. This side to side flop also creates a dangerous situation as, during the flopping motion, there are two stable positions that the front wheel assembly, steering assembly and handlebars can move to. In the first stable position, the front wheel moves a short distance until it rests against the main frame assembly. In the second stable position, the front wheel assembly pivots within the main steering axis within the head set casting until the front wheel axis of rotation is perpendicular to the main frame plane. In both stable positions the centre of gravity of the bicycle lies closer to the ground than before folding but in the second stable position it is much closer to the ground. The end result is that during folding the user experiences a situation in which the front wheel assembly, steering assembly and handlebars might first move into the first stable position but then, with only a small nudge to the bicycle, suddenly move into the second stable position. As the centre of gravity drops considerably during this flopping motion, there is a lot of energy released that the user has to suddenly control - the front section of the semi-folded frame effectively falls through a distance. This sudden flopping and drop can result in trapped fingers and hands as well as bruised and scratched lower legs.

Summary of the Invention

It is an object of the invention to provide a folding bicycle in which the side to side flop noted above is controlled by locking the parts that flop to a single, defined position. This will make the folding procedure easier and safer for the user.

Brief Description of the Drawings

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the Prior Art, GB2475793A (Lambert), showing the bicycle in it folded position.

Figure 2 is a perspective view of a folding bicycle 1 according to a first embodiment of the invention comprising; a main frame assembly 2, a seat assembly 3, a rear swing arm assembly 4, front fork assembly 5, upper steering assembly 7, steering clamp casting 9 and head tube casting 10.

Figure 3 is a perspective view of the folding bicycle 1 of figure 2 with the upper steering assembly 7 folded down.

Figure 4 is a perspective view of the folding bicycle 1 of figure 3 with the front fork assembly 5, upper steering assembly 7, handlebar assembly 18, steering clamp casting 9 and head tube casting 10 pivoted about main hinge pin 17 into the ideal folded position.

Figure 5 is a perspective view of the folding bicycle 1 of figure 4 with the front fork assembly 5, upper steering assembly 7, handlebar assembly 18 and steering clamp casting 9 having flopped into an undesirable position as would occur if the new locking details that are disclosed in figures 5, 6 and 7 were not operative.

Figure 6 is a perspective view of the head tube casting 10 of the folding bicycle 1 of figure 2 showing a new inner locking protrusion 30.

Figure 7 is a perspective view of the folding bicycle 1 of figure 2 showing the front fork 11 with front wheel 12 removed, upper steering assembly 7 (with handlebar assembly 18 removed), steering clamp casting 9 and head tube casting 10 with new outer locking protrusions 32, showing the upper steering assembly 7 folded to a position just before the inner locking protrusion 30 and outer locking protrusions 32 engage.

Figure 8 is a perspective view of the components shown in figure 7 with the upper steering assembly 7 folded to a locked position in which the inner locking protrusion 30 and outer locking protrusions 32 are fully engaged.

Description of the Preferred Embodiment

Referring to figure 1, a PRIOR ART folding bicycle 101 comprises a main frame assembly 102, a seat assembly 103, a rear swing arm assembly 104, front fork assembly 105, main hinge lock 106, upper steering assembly 107, steering clamp casting 109 and head tube casting 110. The front fork assembly comprises a front fork 111, a front wheel 112, a steerer tube 113 (not visible) that passes through head casting 110 and has steering clamp casting 109 attached to it. A steering hinge pin 114 passes through the steering clamp casting 109 and the upper steering casting 108. A main hinge pin 117 passes through the head tube casting 110 and the main frame assembly 102. Also visible are main hinge lock 106, rear wheel 115, drive assembly 116 with drive chain not shown and handlebar assembly 118.

Referring to figure 2, a folding bicycle 1 comprises a main frame assembly 2, a seat assembly 3, a rear swing arm assembly 4, front fork assembly 5, upper steering assembly 7, steering clamp casting 9 and head tube casting 10. The front fork assembly comprises a front fork 11, a front wheel 12, a steerer tube 13 (not visible) that passes through head casting 10 and has steering clamp casting 9 attached to it. A steering hinge pin 14 passes through the steering clamp casting 9 and the upper steering casting 8. A main hinge pin 17 passes through the head tube casting 10 and the main frame assembly 2. Also visible are main hinge lock 6, rear wheel 15, drive assembly 16 with drive chain not shown and handlebar assembly 18. Steering axis 40 is the steering axis of the folding bicycle 1 running through head tube casting 10 and about which the upper steering assembly 7, handlebar assembly 18 and front fork assembly 5 pivot to steer.

Referring to figure 3, the upper steering assembly 7 is shown folded down about steering hinge pin 14 so that the handlebar assembly 18 lies alongside and generally parallel to the front wheel 12. At this stage, the combined front fork assembly 5, upper steering assembly 7, steering clamp casting 9 and steering hinge pin 14 are free to pivot within head tube casting 10 about steering axis 40.

Referring to figure 4, the main hinge lock 6 has been released and head tube casting 10 has been pivoted about main hinge pin 17 so that front fork assembly 5 is folded towards the rear wheel 15. As head tube casting 10 pivots about main hinge pin 17, the combined front fork assembly 5, upper steering assembly 7, steering clamp casting 9 and steering hinge pin 14 are still free to pivot within head tube casting 10. Steering axis 40 has moved with head tube 10 to a new, folded position.

Referring to figure 5, the combined front fork assembly 5, upper steering assembly 7 with handlebar assembly 18 , steering clamp casting 9 and steering hinge pin 14 are shown after pivoting about steering axis 40 within head tube casting 10 to an undesirable position. The resulting position of front wheel 12 interferes with subsequent folding of the rear swing arm assembly 4 (not shown) and the front wheel 12 needs to be returned to the position shown in figure 4 to allow further folding. This flopping of the front wheel 12 is undesirable as it is difficult for the person folding the bicycle to control. In figure 5, the position that the front wheel 12 flops to would occur if the new locking details described below were not operative.

Referring to figure 6, head tube casting 10 with steering axis 40 is shown with an inner locking protrusion 30.

Referring to figure 7, the front fork 11 and steering clamp casting 9 are shown below and above the head tube casting 10 and they are connected to each other by the steerer tube 13 (not visible as it passes through the head tube casting 10 and steering clamp casting 9). The upper steering assembly 7, comprising the upper steering tube 31 and the upper steering casting 8, are shown partially folded down about steering hinge pin 14. A pair of outer locking protrusions 32 are shown attached to upper steering casting 8 and inner locking protrusion 30 can be seen on main tube casting 10. Steering lock assembly 33 can also be seen in this view.

Referring to figure 8, the upper steering tube 31, upper steering casting 8 and steering lock assembly 33 are shown fully folded down about steering hinge pin 14. Pair of outer locking protrusions 32 on upper steering casting 8 and inner locking protrusion 30 on main tube casting 10 are now fully engaged and stop any rotational movement between the upper steering assembly 7 and the head tube casting 10 about steering axis 40. Rotational movement between front fork assembly 5 about steering axis 40 is also stopped as front fork 11 is connected to the upper steering assembly 7 via steerer tube 13 (not visible), steering clamp casting 9 and steering hinge pin 14. As a result, the front wheel 12 is locked in a fixed position so long as upper steering casting 9 is folded down and inner locking protrusion 30 is engaged between pair of outer locking protrusions 32.

The result of the new locking method described above is that when the upper steering assembly 7 is folded down against the head tube casting 10, the inner locking protrusion 30 and outer locking protrusions 32 engage and prevent any flop of the front wheel and front fork assembly that would interfere with subsequent folding steps of the folding bicycle 1.

It will be appreciated that various changes and modifications can be made to the embodiment of the invention without departing from the scope of the claims.

folding bicycle main frame assembly seat assembly rear swing arm assembly front fork assembly main hinge lock upper steering assembly upper steering casting steering clamp casting head tube casting front fork front wheel steerer tube steering hinge pin rear wheel drive assembly main hinge pin handlebar assembly inner locking protrusion upper steering tube outer locking protrusion steering lock assembly steering axis

PRIOR ART

101 folding bicycle

102 main frame assembly

103 seat assembly

104 rear swing arm assembly

105 front fork assembly

106 main hinge lock

107 upper steering assembly

108 upper steering casting

109 steering clamp casting

110 head tube casting

111 front fork

112 front wheel

113 steerer tube

114 steering hinge pin

115 rear wheel

116 drive assembly

117 main hinge pin

118 handlebar assembly

Claims

Claim 1

A steering lock for a folding bicycle comprising:

A head tube casting 10 with a steering axis 40 passing through it and having at least one inner locking protrusion 30 that projects from it;

A steerer tube 13 that passes through the head tube casting 10 and which rotates around steering axis 40;

A steering clamp casting 9 that clamps to steerer tube 13 above head tube casting 10 and rotates with steerer tube 13 around steering axis 40;

A steering hinge pin 14 that passes through steering clamp casting 9 and which is perpendicular to and offset to steering axis 40 and offset above the top of head tube casting 10;

An upper steering casting 8 that pivots about steering hinge pin 14 and has at least one outer locking protrusion 32 projecting from it;

And which is characterised by the outer locking protrusion 32 being brought to a position in which it interferes with inner locking protrusion 30 when upper steering casting 8 is rotated about steering hinge pin 14 and steering clamp casting 9 is rotated about steering axis 40.
Claim 2

A steering lock for a folding bicycle according to claim 1, wherein one inner locking protrusion 30 is so positioned to interlock between two outer locking protrusions 32 so that rotary motion of the steerer tube 13 within the head tube casting 10 is not possible.
Claim 3

A steering lock for a folding bicycle according to claim 1, wherein one outer locking protrusion 32 is so positioned to interlock between two inner locking protrusions 30 so that rotary motion of the steerer tube 13 within the head tube casting 10 is not possible.
Claim 4

A steering lock for a folding bicycle according to claims 1,2 or 3, in which the weight of an upper steering assembly 7 that is attached to upper steering casting 8 keeps the inner and outer locking protrusions 30, 32 engaged when the upper steering assembly 7 is folded down from its unfolded position.