Patent Application
20180274651
Chainrings are sprockets that are attached to a crank of a bicycle. As used herein, the term “sprocket” refers to a toothed gear or wheel used to connect to a chain or belt, and the term “crank” is used to refer to the level arm between the pedal and the bottom bracket. Some bicycles often include one, two, or three chainrings. In bicycles that include more than one chainring, the chainrings are stacked adjacent to each other with minimal lateral spacing there between to facilitate gear shifting. As chains are narrow the spacing between the adjacent chainrings is also decreases. From time to time, the chainrings are removed and replaced due to wear and/or to adjust the drive ratio of the bicycle. There is a need in the art for chainrings that can be placed closer to each other and can be removed and replaced easier.
The present disclosure provides a new chainring system and method of installing and removing a chainring. The system eliminates the need for the use of special tools to install and remove a chainring.
Referring to the FIGS., generally the chainring of the present disclosure is described herein in further detail. In the depicted embodiment, the chainring assembly includes a ring shaped body 10 with a central through opening 12 and a plurality of tabs 14, 16, 18, 20, 22 that extend inwardly from a ring-shaped body portion 10. In the depicted embodiment, the body 10 includes a plurality of teeth 24 arranged about a periphery edge 26. In the depicted embodiment, the teeth 24 are configured to engage a chain and the periphery edge 26 of the chainring defines a circular shape. However, it should be appreciated that alternative embodiments exist. For example, the teeth could be configured to engage a belt and the chainring can be non-circular (e.g., oval). In the depicted embodiment, the chainring body is a machined piece of aluminum. However, it should be appreciated that many other constructions are also possible (forged alloys, carbon fiber composites, steel, etc.)
In the depicted embodiment, the chainring body 10 includes a first side 28 and an opposed second side 30. In the depicted embodiment, each tab 14, 16, 18, 20, 22 includes a locking recess 32 in the second side 30 that include a through aperture 34 that extend from the second side 30 to the first side 28 of the body 10. In the depicted embodiment, the aperture 34 in each of the tabs are located the same distance from a center point CP of the chainring body 10. In the depicted embodiment, each of the locking recesses 32 and through aperture 34 are identical. However, it should be appreciated that in alternative embodiment they aperture and recesses could have different configurations.
In the depicted embodiment, the locking recess 32 includes a non-circular periphery profile. For example the locking recess in
In the depicted embodiment, the assembly also includes an insert 36 that configured to be received within at least a portion of the locking recess 32 such that the rotation of the insert 36 relative to the chainring body 10 is constrained when the insert 36 is engaged with the locking recess 32. In the depicted embodiment, the rotational constraint is due to interference between the locking recess 32 and the flange 38 (e.g., interlocking engagement between the locking recess 32 and the flange 38). In the depicted embodiment, the flange 38, 46 has the same periphery shape as the locking recess. However, as discussed above the rotational constraint could alternatively be due to interference between other portions of the insert (e.g., the tube portion 40) and other portions of the chainring body (the aperture 34). As discussed above, in the depicted embodiment, the insert 36 includes a flange 38 configured to interlock with the locking recess 36 and a threaded tube portion 40 connected to the flange 38 that is configured to be received by the insert receiving aperture 34. In the depicted embodiment, the flange 38 has a thickness that is less than or equal to the depth of the locking recess (e.g, about 1-4 millimeters). In the depicted embodiment, the insert is formed of steel. It should be appreciated that many other construction are also possible (e.g., titanium, alloys, etc.).
In the depicted embodiment, the assembly also includes a faster 42 including a threaded portion that is configured to extend through the body 10 from the first side of the chainring body 10 and engage the threaded tube portion 40 of the insert 36.
The present disclosure also provides a new method of installing a chainring that includes the steps of engaging a flange of a threaded insert with a recess in the chain ring body; aligning the threaded insert with an aperture in a spider of a crank arm; inserting a threaded bolt through the aperture in the spider; and engaging the threads of the bolt with the thread of the threaded insert. In the depicted embodiment, the step of engaging the threads on the both with the threads of the threaded insert requires the use of only a single hex tool. In the depicted embodiment the insert with the flange establishes concentricity for the chainring to the spider when engaged with the threaded bolt. This method eliminates the need for a special tool to remove and install chainrings.
The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
