Patent Application
20080238027
1. Field of the Invention
The present invention generally relates to bicycles and, more specifically, to joining of components of a bicycle frame.
2. Description of the Related Art
One type of bicycle frame is an assembly of multiple components assembled together into a desired shape. The individual components of such a bicycle frame may comprise metal tubes that are cut, shaped and joined together, typically by a welding process and/or composite tubes that are cut, shaped and bonded together typically using adhesive. In general, a bicycle frame is configured to support a seat assembly, a pedal crank assembly, a rear wheel and a steering assembly. The steering assembly typically includes a handlebar, front fork and front wheel coupled to one another and permitted to rotate relative to the bicycle frame. If the associated bicycle is intended for off road use, the bicycle frame may provide rear wheel suspension. Such a frame may include a main frame and sub-frame pivotally connected to the main frame. The sub-frame supports the rear wheel and a shock absorber may be connected between the main frame and the sub-frame to influence relative movement between the main frame and the sub-frame.
Commonly, when composite tubes are used in the construction of a bicycle frame it is at times desirable that the components that are bonded to the composite tubes be made of a different material such as an aluminum, magnesium, or steel. This is often common when bonding dropouts to seat stays or chain stays of a bicycle frame. The connection between the dropouts and the seat stays or chain stays is a particularly high-stress connection, which requires a relatively large contact surface area and proper adhesive application in order to obtain a strong connection.
Presently a dropout that can be bonded to a composite seat stay or chain stay and transmit disc brake loads is commonly large and overbuilt in order to transmit braking forces.
Thus, a need exists for a lightweight dropout that can be bonded to a composite chain stay or seat stay and support and transmit disc brake loads.
A preferred embodiment is a bicycle frame dropout including an axle recess being capable of receiving at least a portion of an axle of a hub of a bicycle wheel. The dropout also includes a disc brake tab integrally formed with the dropout. A pivot bearing support is integrally formed with the dropout. A cavity is sized and shaped to receive a stay. The cavity includes a mounting interface, which comprises a first surface and a second surface facing the first surface. The first surface and the second surface are capable of permitting rotation of the stay relative to the dropout in a first rotational direction and opposing rotation of the stay relative to the dropout in a second rotational direction opposite the first rotational direction.
Another preferred embodiment is a bicycle frame lug including a cavity sized and shaped to receive a frame member. The cavity includes a mounting interface, which comprises a top surface, a bottom surface, a first side surface, a second side surface, and an end surface. The first side surface and the second side surface are capable of permitting lateral rotation of the frame member in a first rotational direction and opposing lateral rotation of the frame member in a second rotational direction opposite the first rotational direction. The end surface is capable of axially supporting the frame member within the cavity.
Yet another preferred embodiment is a bicycle frame including a main frame and a subframe pivotally connected to the mainframe. A frame component is attached to the subframe and includes a cavity sized and shaped to receive a portion of the subframe. The cavity includes a mounting interface, which comprises a top surface, a bottom surface, a first side surface, a second side surface, and an end surface. The first side surface and the second side surface are capable of permitting lateral rotation of the portion in a first rotational direction and preventing lateral rotation of the portion in a second lateral rotational direction opposite the first rotational direction.
An aspect of the present invention involves a method of attaching a bicycle frame tube to a frame component, including inserting the frame tube into a cavity of the frame component at an insertion angle that is not aligned with a longitudinal axis of the cavity and rotating the frame tube until the frame tube is substantially aligned with the longitudinal axis of the cavity and contacts both a first surface and a second surface defined by opposing wall portions of the frame component.
These and other features, aspects, and advantages of the present invention will now be described in connection with preferred embodiments of the invention, in reference to the accompanying drawings. The illustrated embodiments, however, are merely examples and are not intended to limit the invention. The drawings include the following eight Figures.
The bicycle 10 includes a frame 12, preferably comprised of a generally triangular main frame portion 14 and an articulating frame portion, or subframe 16. The subframe 16 is pivotally connected to the main frame 14. The bicycle 10 also includes a front wheel 18 carried by a front suspension assembly, or front fork 20. A steerer tube (not shown) is journaled for limited rotation about a steering axis defined by the main frame 14. The fork 20 is secured to the main frame 14 by a handlebar assembly 22, as is well known in the art. A rear wheel 24 of the bicycle 10 is carried by the subframe 16. A shock absorber 26 is pivotally connected to both the main frame 14 and the subframe 16 to provide resistance to the pivoting motion of the subframe 16 and, thus, provide resistance to the suspension travel of the rear wheel 24.
In addition, a seat 28 is connected to the frame 12 by a seat post 30, which is received within the seat tube of the main frame 14. The seat 28 provides support for a rider of the bicycle 10. A pedal crank assembly 32 is rotatably supported by the main frame 14 and drives a multi-speed chain drive arrangement 34, as is well known in the art. The bicycle 10 also includes front and rear brake systems 36, 38 for slowing and stopping the bicycle 10. Although the front and rear brakes 36, 38 are illustrated as disc type brakes, alternatively, rim type brakes may be provided, as will be appreciated by one of skill in the art. Rider controls (not shown) are commonly provided on the handlebar assembly 22 and are operable to control shifting of the multi-speed chain drive arrangement 34 and front and rear brake systems 36, 38.
With reference to
Attached to the forward portion of each of the stays 56 and 58 preferably are pivot lugs 62 and 64 that are configured to pivotally attach the seat stay assembly 42 to the rocker link assembly 44. The pivot lugs 62 and 64 preferably are the outer portions of a clevis type pivot assembly in which portions of the rocker link assembly 44 are inserted into the pivot lugs 62 and 64. As will be appreciated by one skilled in the art, the pivot lugs 62 and 64 are one example of a suitable pivot types and other suitable pivot types may also be used. The pivot lugs 62 and 64 preferably comprise a portion of material that extends rearward so as to insert into the stays 56 and 58 such that the pivot lugs 62 and 64 have a certain amount of structural overlap with the stays 56 and 58.
The lugs 62 and 68, in some embodiments receive a large amount of force during normal operating conditions and also require a great deal of precision manufacturability in order to precisely couple to the rocker link assembly 44. Thus, it is preferable, in some embodiments, to construct the pivot lugs 62 and 64 of the metallic material such as aluminum, magnesium, scandium, or steal such that greater durability and precision can be achieved. This is particularly advantageous in that the seat stay assembly 42 can be a lighter assembly by using a carbon fiber or composite material to construct the stays 56 and 58 while reserving the heavier but more durable materials for the specific wear prone positions such as the pivot lugs 62 and 64 and the dropouts 46 and 48.
With continued reference to
With reference to
In the particular illustrated embodiment, the axle recess 82 preferably is a 10 mm quick release style axle recess such that a typical 10 mm hub axle may reside within the axle recess 82. As will be appreciated by one skilled in the art, the axle recess 82 may be of any suitable size, including that suitable for a 20 mm thru-axle or a 12 mm thru-axle. Furthermore, although the particular illustrated embodiment has been shown with a non-drive side dropout 48 that comprises both an axle recess 82 and an cavity 86 for mounting a non-drive side stay 58, in other embodiments the non-drive side dropout 48 may be configured such that it is attached to a chain stay with the disc brake tab 84 attached to a separate frame component. That is, in some embodiments, the non-drive side dropout 48 may comprise an axle recess, a cavity for the non-drive side stay, and a pivot bearing support, omitting the disc brake tab. In other embodiments the non-drive side dropout 48 may comprise a cavity for receiving a stay, a pivot bearing support, and a disc brake tab, omitting the axle recess. As will be appreciated by one skilled in the art this aforementioned alternative is commonly used with a four bar linkage in which the rear wheel hub is carried by the chain stay rather than the seat stay. Such a construction is often referred to as a “faux” four bar linkage in the bicycle industry.
In the particular illustrated embodiment, the disc brake tab 84 is a typical 51 mm international standard rear wheel disc brake tab that is configured to receive a typical 51 mm international standard disc brake caliper. As illustrated, the disc brake tab preferably comprises a forward or upper tab portion 84a and a rearward or lower tab portion 84b that cooperate to define the disc brake tab 84. Each of the tab portions 84a and 84b both preferably are configured to receive a 6 mm bolt that is typically used to attach a disc brake caliper. As will be appreciated by one skilled in the art, other suitable disc brake tabs may be used such as a 74 mm post mount or a 51 mm international standard tab that is configures to directly receive brake calipers for 4″, 6″, 7″, or 8″ disc rotors. Furthermore, in some embodiments the disc brake tab 84 may be omitted for such bicycle designs that do not use a disc brake but used a rim style brake or a coaster style brake.
In some embodiments, it is preferable to bond the stay 58 to the dropout 46 by a suitable adhesive. This can be particularly advantageous when the dropout 48 is made of a metal such as aluminum, scandium, steel, or magnesium and the non-drive side stay 58 is made of a composite such as carbon fiber or thermoplastic. When the non-drive side stay 58 is made of a composite it is highly unlikely that coalescence-type welding (e.g., arc welding) will be a suitable process to join the non-drive side dropout 48 to the non-drive side stay 58. Thus, as will be appreciated by one skilled in the art, using adhesive or other chemical joining processes can be particularly advantageous.
With continued reference to
The side surfaces 94 and 96 preferably are arranged in a spaced-apart configuration such that they face one another and are arranged such that they are at least partially offset along the axis AC (
This arrangement of the side surface 94 and the side surface 96 also defines a stay opening 100 in which the non-drive side stay 58 can be inserted laterally through the non-drive side dropout 48 (see
A method for installing the non-drive side dropout 48 onto the non-drive side stay 58 is described with reference to
The method of attaching the stay 58 to the dropout 48 is particularly advantageous in that the amount of adhesive that is wiped away during installation of the non-drive side stay 58 is substantially reduced. That is, in some prior art embodiments, a stay opening is provided in which a stay must be inserted into a recess or cavity such that the insertion angle is such that the longitudinal axis of the stay and the longitudinal axis of the recess are aligned during the insertion process. Thus, when adhesive is applied to such an arrangement a great deal of the adhesive is wiped away during insertion of the stay. With the above described embodiment, the non-drive side stay 48 can be inserted into the non-drive side dropout 58 by an insert and twist method while a substantial amount of adhesive is maintained in proper position on the mounting interface 88 such that an excellent bonding connection can be achieved.
Furthermore, the particular shape of the mounting interface 88 is also particularly advantageous in that it efficiently and effectively transfers torque to non-drive side stay 58 during operation, particularly with a disc brake caliper. That is, the shape of the mounting interface 88 is such that vertical rotation of the stay 58 is resisted by the shape of the dropout 48, in particular by the top and bottom wall surfaces 90, 92. This is particularly advantageous because this is the direction of the force that is quite often produced by a disc brake caliper. Furthermore, the mounting interface 88 is sized and shaped such that the stay can rotate laterally in one direction and lateral rotation in an opposite direction is substantially resisted or prevented. Once again, this is advantageous in that typically a dropout such as the non-drive side dropout 48 on a typical bicycle does not experience large amplitude lateral rotational forces and thus side rotational restraint provided by the adhesive is ample to maintain the non-drive side dropout 48 in a secured configuration with the non-drive side stay 58. However, in other applications, it may be desirably to insert the stay (or other frame tube or member) into the dropout (or other frame lug or component) in a different relative orientation. For example, in one arrangement, the top and bottom surfaces could be offset from one another such that the stay is inserted at an angle with the dropout cavity in a vertical direction and rotated vertically upward or downward into position within the cavity. In other arrangements, the walls defining the cavity may not be arranged in a top, bottom, left, right fashion, but may be rotated therefrom. Furthermore, the walls defining the cavity may include rounded or circular surfaces, rather than the generally flat surface shown herein.
Another particular advantage provided by the mounting interface 88 of the non-drive side dropout 48 described above is the ease at which the non-drive side dropout 48 can be manufactured. Due to the open nature of the mounting interface 88 when the non-drive side dropout 88 is to be manufactured it can easily be forged using conventional methods such that minimal amounts of post-forge machining are needed to finalize the mounting interface 88 or any other of the attributes of the non-drive side dropout 48. Furthermore, if one were to prefer a machining manufacturing method, that too could be more easily achieved in that the open nature of the mounting interface 88 is once again easily accessible for machining using, for example, a rotary machining tool. The prior art dropouts that use a laterally enclosed opening to receive a stay are very difficult and costly to machine the opening. Furthermore, in some prior art embodiments it is nearly impossible to forge the opening to receive the stay.
Although the above described embodiment with reference to the figures has been described with reference to a non-drive side dropout 48, other suitable embodiments are also within the scope of the technology. For example, as will be appreciated by one skilled in the art, the mounting interface 88 can be employed with a wide variety of frame components including fork dropouts, bottom bracket lugs, frame tube juncture lugs, seat post clamps, head tube lugs, drive side dropout's, suspension pivot eyelet lugs, or other suitable frame components, including fork leg-to-lug connections. Furthermore, as will be appreciated by one skilled in the art, the mounting interface 88 can be used with a dropout or frame lug on any full suspension frame or hardtail frame. The above disclose technology can equally be used with, what is vernacularly referred to in the art as, a Horst Link or a non-Horst Link, or faux link, style suspension frame. Also, the above described technology can be equally used with frame components such as dropouts on single pivot style suspension frames.
Furthermore, although the above described embodiment has been disclosed with reference to a metallic frame component and a composite frame tube, the technology can just as easily be used with a metallic frame tube and a metallic frame component that may be welded or bonded together, or a composite frame tube and a composite frame component that may be bonded together as described above.
Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while the number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to perform varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims.
