US-12623741-B2 - Positionally optimized saddle dropper post

US12623741B2US 12623741 B2US12623741 B2US 12623741B2US-12623741-B2

Abstract

A bicycle frame includes a front triangle comprising a head tube and a bottom bracket shell, a tension bar comprising a first end and a second end, wherein the first end of the tension bar is pivotably connected to an upper portion of a telescoping seat post assembly, and a first fore pivot assembly at a first reach point. The first reach point is between a reach point of the bottom bracket shell and a reach point of the head tube. The first fore pivot assembly is pivotably connected to the second end of the tension bar. The frame further includes an aft pivot assembly at a second reach point, wherein the second reach point is closer to the reach point of the bottom bracket shell than the first reach point, and wherein the aft pivot assembly is pivotably connected to a lower portion of the telescoping seat post assembly.

Inventors

Christopher James Killer

Assignees

Christopher James Killer

Dates

Publication Date: 20260512
Application Date: 20220420

Claims (20)

1 . A bicycle frame comprising: a front triangle comprising a head tube and a bottom bracket shell; a tension bar comprising a first end, a second end, and one or more bends between the first end and the second end, wherein the first end of the tension bar is pivotably connected to an upper portion of a telescoping seat post assembly, the telescoping seat post assembly having a lower portion and the upper portion, the lower portion comprising a hollow section of material, the upper portion comprising a second hollow section of material proportioned to slide along an interior surface or exterior surface of the lower portion; a first fore pivot assembly at a first reach point, wherein the first reach point is between a reach point of the bottom bracket shell and a reach point of the head tube, and wherein the first fore pivot assembly is pivotably connected to the second end of the tension bar; and an aft pivot assembly at a second reach point, wherein the second reach point is closer to the reach point of the bottom bracket shell than the first reach point, and wherein the aft pivot assembly is pivotably connected to the lower portion of the telescoping seat post assembly.
2 . The bicycle frame of claim 1 , further comprising: a top tube assembly comprising a first end and a second end, wherein the first end of the top tube assembly is connected to the head tube, and wherein the second end of the top tube assembly comprises a portion in which a centerline of the frame is exposed proximate to the aft pivot assembly.
3 . The bicycle frame of claim 1 , further comprising: a seat tube assembly comprising a first end and a second end, wherein the first end of the seat tube assembly is connected to the bottom bracket shell, and wherein the second end of the seat tube assembly comprises a portion in which a centerline of the frame is exposed proximate to the aft pivot assembly.
4 . The bicycle frame of claim 1 , further comprising a top tube assembly connected to the head tube, wherein the first fore pivot assembly is connected to the top tube assembly proximate to the head tube.
5 . The bicycle frame of claim 1 , wherein the lower portion of the telescoping seat post assembly comprises a seat clamp.
6 . The bicycle frame of claim 1 , wherein when the telescoping seat post assembly is moved from a compressed first position to an extended second position, the telescoping seat post assembly pivots from a first effective seat tube angle to a second effective seat tube angle, and wherein the second effective seat tube angle is closer to vertical than the first effective seat tube angle.
7 . The bicycle frame of claim 6 , wherein when the telescoping seat post assembly is at the compressed first position, a saddle is at a first seat reach point, wherein when the telescoping seat post assembly is at the extended second position, the saddle is at a second seat reach point, wherein the second seat reach point is closer to the head tube than the first seat reach point.
8 . The bicycle frame of claim 1 , further comprising: a second fore pivot assembly at a third reach point, wherein the third reach point is between a reach point of the bottom bracket shell and the first reach point; a first linkage pivotably connecting the first end of the tension bar to the first fore pivot assembly; and a second linkage pivotably connecting the second fore pivot assembly to an attachment point on the tension bar.
9 . The bicycle frame of claim 8 , further comprising: a top tube assembly connected to the head tube, wherein the second fore pivot assembly is connected to the top tube assembly.
10 . The bicycle frame of claim 8 , further comprising: a top tube assembly connected to the head tube, wherein first fore pivot assembly is connected to the top tube assembly.
11 . The bicycle frame of claim 8 , further comprising: a down tube assembly, wherein the first fore pivot assembly is connected to the down tube assembly.
12 . The bicycle frame of claim 1 , further comprising: a first top stay connected at a first end to the head tube and at a second end to a first rear dropout; and a second top stay connected at a first end to the head tube and at a second end to a second rear dropout, wherein the aft pivot assembly is connected to both the first top stay and the second top stay.
13 . The bicycle frame of claim 1 , wherein a length of the tension bar is adjustable.
14 . The bicycle frame of claim 1 , wherein a pivot point of the first fore pivot assembly is adjustable.
15 . The bicycle frame of claim 1 , wherein an effective seat tube angle of the telescoping seat post assembly increases as the telescoping seat post assembly extends.
16 . The bicycle frame of claim 15 , wherein the effective seat tube angle of the telescoping seat post assembly increases substantially linearly as the telescoping seat post assembly extends.
17 . The bicycle frame of claim 15 , wherein the effective seat tube angle of the telescoping seat post assembly increases progressively as the telescoping seat post assembly extends in length.
18 . The bicycle frame of claim 1 , wherein the aft pivot assembly comprises: a retaining tube sized to fit the lower portion of the telescoping seat post assembly; a clamp for compressing the retaining tube around the lower portion of the telescoping seat post assembly; and an axle hanger connected to the retaining tube.
19 . A bicycle frame comprising: a front triangle comprising a head tube and a bottom bracket shell, a tension bar comprising a first end and a second end, wherein the first end of the tension bar is pivotably connected to an upper portion of a telescoping seat post assembly, the telescoping seat post assembly having a lower portion and the upper portion, the lower portion comprising a hollow section of material, the upper portion comprising a second hollow section of material proportioned to slide along an interior surface or exterior surface of the lower portion; a first fore pivot assembly at a first reach point, wherein the first reach point is between a reach point of the bottom bracket shell and a reach point of the head tube, and wherein the first fore pivot assembly is pivotably connected to the second end of the tension bar; and an aft pivot assembly at a second reach point, wherein the second reach point is closer to the reach point of the bottom bracket shell than the first reach point, and wherein the aft pivot assembly is pivotably connected to the lower portion of the telescoping seat post assembly.
20 . The bicycle frame of claim 19 , wherein the front triangle further comprises at least one structure that connects the head tube to the bottom bracket shell, wherein the at least one structure is directly connected to the head tube without a pivot and directly connected to the bottom bracket shell without a pivot.

Description

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63/185,000 filed on May 26, 2021, the contents of which are incorporated by reference as if fully set forth herein. TECHNICAL FIELD This disclosure relates to bicycles, and in particular, bicycles for riding off-road, such as mountain bikes, fat bikes and certain cyclo-cross or gravel bikes. More specifically, the present disclosure is directed to embodiments of a positionally optimized saddle dropper post. BACKGROUND Bicycles for primarily off-road use, including, without limitation, mountain bikes, fat bikes, and certain cross, or gravel bikes have evolved significantly since the first bicycles referred to as mountain bikes were sold in the late 1970s. Improvements in geometry, componentry, suspension, and tires have produced bicycles which are lighter, maintain traction, and more readily absorb than previous generations of bicycles. As such, modern off-road bicycles are highly capable and can typically climb, descend, and negotiate technical terrain better much better than older bikes. Dropper seat posts, typically comprising an upper half attached to the bicycle's saddle and a lower half, retained in a frame's seat tube, which allow the extension of the seat post to be adjusted on the fly, have contributed significantly to the modern bikes' ability to negotiate a wide variety of terrains and riding conditions. For example, a dropper seat post allows a rider to compress the seat post before descents and technical sections to a position closer to the top tube, thereby reducing the extent to which the saddle hinders the rider's ability to move her weight back and forth, as well as up and down. At the same time, a dropper seat post may be extended before climbing and sprinting such that the saddle is located further away from the bottom bracket, thereby supporting the rider's weight, and allowing for fuller leg extension when pedaling. Dropper seat posts in which an upper half telescopes relative to a lower half also provide the practical benefits of being simple to manufacture and service, relatively lightweight, and can be retrofitted to older frames. However, extending a dropper seat post along a single axis of reciprocation typically decreases the effective seat tube angle of the bicycle, while at the same time, maintaining the same saddle pitch across seat heights. This presents several recognized biomechanical problems, particularly when the dropper post is fully extended. First, while there are several models for optimizing a rider's seat position for pedaling efficiency, there is a general consensus that optimum pedaling efficiency at a full seat height is typically maximized when the seat is positioned such that a rider's front knee and front pedal are vertical when the pedals are horizontal. In other words, pedaling efficiency is maximized when, at the point of the pedal stroke where maximum force is applied by the rider's foot, the force applied by the rider is perfectly normal to the lever arm between the pedal and the bottom bracket. Further, pedaling efficiency is also maximized when the rider's center of mass is, to the extent possible, directly above the downstroke of the pedal. For this reason, track, triathlon, and other bicycles designed to efficiently translate the pedaling power of a rider in a “high” riding position where a rider can apply maximum force to a pedal have steep seat tube angles, typically between 78-80 degrees. Second, in addition to maximizing pedaling efficiency, maintaining perpendicularity between a rider's front knee and the front pedal at point of maximum power minimizes the incidence of knee pain arising from the rider applying full pedaling force obliquely to the lever arm of the pedal. For this reason, comfort, hybrid, and other bicycles designed around the expectation of a low saddle position have comparatively “slack” seat tube angles, of around 72 degrees or less. Third, raising the saddle height without decreasing saddle pitch (i.e., the angle of the saddle relative to the bicycle) increases the amount of rider weight placed on the forward, narrower portion of the saddle, which can, in mild cases, cause rider discomfort, and in more severe cases, can damage riders' reproductive health. In contrast to time trial and comfort bicycles, whose geometry has a single performance objective, such as maximizing efficient power transfer or maximizing rider comfort, the geometry of modern off-road bicycles represents a compromise between multiple diverse performance objectives and design considerations. For example, to improve control when descending on bumpy terrain, modern mountain bicycles have “long and slack” frame geometries, typically characterized by longer wheelbases, larger wheels (i.e., 29″ wheels, as opposed to 27.5″ or 26″ wheels) slacker (i.e., shallower) head tube angles and more suspension travel