Bicycle frame, rod system and method of assembly

Abstract

A lever assembly for a bicycle, comprising: a handlebar portion; a rod attached or attachable to the handle portion; a steering tube extendable through a head tube portion of the bicycle; and an attachment mechanism for securing the steering tube to the rod, where the attachment mechanism includes a wedge element configurable to force a portion of the steering tube into engagement with the inner surface of the rod.

Description

Technical Field

[0001] The preferred embodiment relates to a bicycle, and more particularly to a bicycle frame. The preferred embodiment relates to a rod system of a bicycle frame and a method of assembling a rod system of a bicycle frame, the rod system being provided for mounting a bicycle handlebar thereon. Background Art

[0002] In a bicycle assembly, an adjustment device for adjusting the height of a stem assembly can be provided at the front of the bicycle to accommodate riders of varying heights and body shapes. The stem assembly supports the bicycle's handlebars, and the adjustment device allows for the use of relatively taller or shorter stem assemblies, depending on the desired overall frame size. The stem assembly typically includes a main stem, which can be comprised of several components, with its lower end connected to the bicycle's front fork and its upper end connected to the handlebars. The number and relative heights of the stem components can be selected to accommodate the overall frame size requirements.

[0003] As is well known, a stem is attached to a bicycle handlebar via a bolt arrangement for manufacturing. However, this attachment arrangement is susceptible to variations in assembly methods. Thus, if the bolts are not fully or correctly tightened, the handlebar can fall off or be mounted in a crooked fashion, which can be dangerous. Overtightening the bolts can also cause the stem to break. Therefore, there is a need for a device for attaching a stem assembly to a handlebar that allows for consistent assembly. Summary of the Invention

[0004] In one aspect, a preferred embodiment provides a bicycle stem assembly. The bicycle stem assembly includes a handlebar portion, a stem attached or attachable to the handlebar portion, and a steering tube extendable through a head tube portion of the bicycle. The assembly includes an attachment mechanism for securing the steering tube to the stem, wherein the attachment mechanism includes a wedge element that can be configured to force a portion of the steering tube into engagement with an inner surface of the stem.

[0005] A stem is attached or attachable to the handlebar portion. A steering tube extends through the head tube portion of the bicycle between the stem and the fork. A wedge element is arranged and configured to force a portion of the steering tube into engagement with a wall of the stem to secure the steering tube to the stem.

[0006] The wedge element may comprise an opening for receiving a fixing means in the form of a steering fixing bolt or screw.The wedge element may be received within the opening of the rod.

[0007] The stem assembly may include adjustment means in the form of a spacer which may be located between the head tube and the stem to adjust the height of the handlebars in use.

[0008] In another aspect, a preferred embodiment provides an attachment mechanism for attaching a steering tube to a stem of a bicycle stem assembly. The attachment mechanism includes a wedge element and a compression screw or bolt that, during use, is received in an opening in the wedge element. To attach the steering tube to the stem, the wedge element and the steering tube are received together in the opening in the stem, and the compression screw or bolt is inserted and advanced into the opening in the wedge element to engage the wedge element with the steering tube and cause the wedge element and the steering tube to engage against the inner surface of the stem, thereby securing the wedge element and the steering tube in the opening in the stem. This, in turn, secures the steering tube in the stem.

[0009] In yet another aspect, a preferred embodiment provides a bicycle frame including a bicycle stem assembly. The stem assembly includes a handlebar portion, a stem, a head tube portion, and a fork. The stem assembly also includes a spacer, also known as an aero spacer, for adjusting the height of the stem assembly. The aero spacer is configured to provide a smooth transition between elements of the stem assembly to improve aerodynamic performance.

[0010] In some embodiments, the air spacer is positioned between the head tube portion and the stem. The air spacer may include an extension portion, the extension portion including an outer surface. The extension portion may be arranged and configured such that the outer surface of the extension portion defines a portion of a continuous outer surface of the frame. The continuous outer surface of the frame also includes an outer surface of the frame's top tube and an outer surface of the stem. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order that the preferred embodiments may be more readily understood, preferred non-limiting embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0012] Figure 1 is a perspective view of a bicycle lever system according to a first embodiment of the present invention; and

[0013] Figure 2 yes Figure 1 A cross-sectional view of a portion of a rod system showing a compression wedge of the rod system. DETAILED DESCRIPTION

[0014] refer to Figure 1 , a bicycle stem system or assembly 10 includes a handlebar portion 14, a stem 16, a head tube portion 18, and a fork 20. A top tube 22 and a down tube 24 of the bicycle frame extend from the head tube portion 18. A steering tube 26 extends through the head tube portion 18 from the fork 20 to the stem 16. Bearings located at the upper and lower ends of the head tube portion 18 support the steering tube 26 for rotation relative to the head tube portion 18, thereby steering the bicycle during use. In this example, the stem 16 defines a V-shaped stem.

[0015] The stem assembly 10 includes a stem attachment system for connecting the stem 16 to the fork 20 via the steerer tube 26. The stem attachment system includes a wedge element 28 that is positioned and configured to push or force an upper portion 30 of the steerer tube 26 into engagement with an inner wall 32 of the stem 16 to secure the steerer tube 26 to the stem 16.

[0016] To secure the steering tube 26 to the rod 16, the wedge member 28 and the upper portion 30 of the steering tube 26 are inserted into the opening in the lower surface of the rod 16. The wedge member 28 is positioned so that the wider portion of the wedge member 28 is positioned closer to the lower surface of the rod 16. A threaded steering securing bolt or screw 34 is then inserted through the opening in the upper surface of the rod 16 into the threaded hole in the wedge member 28. As the bolt or screw 34 is advanced further into the threaded hole opening, the complementary threaded coupling of the bolt 34 and the threaded retaining member of the wedge member 28 engage, and the wedge member 28 is pulled upward toward the upper surface of the rod 16. This causes the wider portion of the wedge member 28 to engage with the upper portion 30 of the steering tube 26 and push the steering tube 26 into engagement with the inner surface 32 of the rod 16, thereby securing the steering tube 26 in the opening in the rod 16.

[0017] The stem assembly 10 may also include adjustment means in the form of an air spacer 50 which may, for example, be positioned between the head tube 18 and the stem 16 to adjust the height of the handlebar portion 14 above the ground and the overall height of the stem assembly 10 in use.

[0018] The air spacer 50 includes an extension portion 52 including an outer surface 54. The extension portion 52 can be arranged and configured such that the outer surface 54 of the extension portion 52 defines a portion of a continuous outer surface or exterior surface 56 of the frame 58. The continuous exterior surface 56 of the frame 58 also includes an exterior surface 60 of the top tube 22 of the frame 58 and an exterior surface 62 of the stem 16.

[0019] The outer surface 54 of the extended portion 52 of the air spacer 50 spans between the upper outer surface of the stem and the upper outer surface 60 of the top tube 22 to provide a smooth, continuous outer surface 56 from the handlebar 14 to and along the upper surface 60 of the top tube 22.

[0020] Without the extension 52, there would be a gap between the rear surface 64 of the stem 16 and the angled surface 66 of the top tube 22. It will be appreciated that such a discontinuity along the surface of the frame 58 could negatively impact the aerodynamic performance of the bicycle. Therefore, the air spacer 50 allows for a smooth and continuous transition between the stem 16 and the top tube 22 for optimal aerodynamic performance while providing height adjustment of the stem assembly 10.

[0021] A variety of different sized handlebar drop ends can be bonded to the middle V-shaped bar. In some examples, the handlebar drop ends are bonded at the factory and are not removable.

[0022] This bar 16 comprises horizontal crossbar, V-shaped vertical tube and the attachment part of bar-steering tube.In one embodiment, these features can define an integral part.In another embodiment, such feature can comprise multiple parts.

[0023] A bearing tensioning system may include a compression screw, a captive nut, and a decorative cap to compression load the head tube bearing assembly.

[0024] A set of clamping screws may be used to secure the V-rod assembly 16 to the steering tube 26 .

[0025] The air spacer 50 allows for vertical adjustment of the handlebar 14 while maintaining aerodynamics and a smooth cosmetic surface. The air spacer 50, which can be of different sizes to provide different height adjustments, is placed on the steering tube 26. The air spacer 50 reaches behind the stem 16 and rises to the top surface 60 of the top tube 22. It also rises to the top surface 62 of the stem 16, thereby bridging the gap between the height range of the top surface 60 of the top tube 22 and the top surface 62 of the lower portion of the stem 16.

[0026] A head tube bearing is provided between the head tube 18 and the steering tube 26 .

[0027] exist Figure 1 In the configuration, the handlebar 14 and stem 16 combination is attached to the steering tube 26 using a mechanism that uses a compression bolt and nut insert to set the steering tube bearing into the frame under the correct preload. The stem 16 is tightened to the steering tube 26 by a steering wedge-type compression mechanism that pushes a wedge element 28 against a surface 70 of the steering tube 26 with increasing force. This force applied by the compression mechanism and the counterbalancing support force applied by the stem 16 provide a friction force that holds the handlebar 14 and stem 16 combination securely to the steering tube 26.

[0028] For more details, refer to Figure 2 , a radial force R acts on the steering tube 26 toward the inside surface 82 of the rod 16. The radial force R increases as the wedge element 28 is urged upward along the axis 80 when the steering fixing bolt or screw 34 is driven into the opening 84 and the complementary threads of the steering fixing bolt or screw 34 engage the inner wall of the opening 84. The radial force R acts in a direction perpendicular to the axis 80.

[0029] In this example, wedge element 28 is defined by a tapered block. The tapered block includes at least one inclined surface 86 to provide a wedge shape. This wedge shape causes the force acting on steering tube 26 to increase as wedge element 28 moves further along axis 80 into the opening in lower surface 88 of rod 16.

[0030] In some examples, a portion or all of the surface of the wedge element 28 that engages the steering tube 26 is flat. A portion or all of the surface 70 of the steering tube 26 that engages the wedge element 28 may also be flat, for example, Figure 2 The engagement provided by utilizing such a flat portion of the wedge member 28 and the steering tube 26 may be more secure than an engagement that would otherwise be achieved, such as by engaging a curved surface of the wedge member 28 and the steering tube 26 .

Claims

1. A rod assembly for a bicycle, comprising: Handlebar part; a stem attached or attachable to said handlebar portion; a steering tube capable of extending through a head tube portion of the bicycle; as well as an attachment mechanism for securing the steering tube to the stem, Wherein the attachment mechanism includes a wedge element, the wedge element can be configured to force a portion of the steering tube into engagement with an inner surface of the stem.

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