WO2011058391A1

WO2011058391A1 - Seat post assembly

Info

Publication number: WO2011058391A1
Application number: PCT/IB2009/055008
Authority: WO
Inventors: Frank Hermansen; Carl Winefordner
Original assignee: Crank Brothers Inc.
Priority date: 2009-11-11
Filing date: 2009-11-11
Publication date: 2011-05-19
Also published as: TW201127676A

Abstract

A seat post assembly has a lightweight bridge (106) that snaps between tubular portions of a seat rail (108), where the bridge has ridges on opposing sides. A clamping mechanism (104) is connected to a seat post (102), where the clamping mechanism has two opposing clamps (116) and a single bolt (126) that attaches the clamps to the seat post. The clamps each have a curved groove (118) matching a curved ridge (112) at the base of the seat post. This allows the seat to be adjusted in angle. Each clamp also has a semi- cylindrical groove (120) that engages "with the tubular portions of the seat rail, where the upper portion of the groove has an opening (130) that engages with the ridges of the bridge to allow the clamping mechanism and bridge to move together and adjust the seat in a fore and aft position. An opening (124) is provided in both clamps for the bolt, where one portion of the bolt has a notch, and one opening has a groove to secure the bolt' when tightening or loosening the bolt.

Description

SEAT POST ASSEMBLY

TECHNICAL FIELD OF THE INVENTION

The present invention generally bicycle components, and in particular to a seat post assembly for securing a seat to a bicycle.

BACKGROUND OF THE INVENTION

A saddle or seat for bicycles are typically affixed to a bicycle frame by a seat post. The height of the seat can be adjusted by moving the seat post up or down within a tubular opening on the bicycle frame. The angle of the seat can typically also be adjusted for the comfort of the rider. There have been many different types of post and clamping mechanisms. However, due to the various components required and ranges of movement or adjustment of the seat and post, such mechanisms tend to be heavy and difficult to use. Some prior art seat assemblies are disclosed in U.S. Pat. No. 5,649,738, U.S. Pat. No. 5,664,829, and U.S. Pat. No. 5,466,042, all of which are relatively heavy and complicated. One recent type of seat assembly is disclosed in U.S. Pat. No. 7,431,391 to Ming-Hung Hsiao. The '391 patent teaches an assembly with outer clamps that pivot around a curved base, a single fastener, and a bridge to support the seat rails. However, as with most seat assemblies, the disclosed assembly is complicated and heavy. For example, the fastener mechanism and clamps require beveled edges to allow clamp rotation, and the fastener mechanism requires a washer (which is curved). Such beveled edges are more complicated to manufacture. Furthermore, the '391 patent shows that the bridge is shaped like a "U" even though the clamping loads cause pure compression between the rails, which means that the bridge "U" shape is not ideal and must be extra thick and strong to withstand the clamping loads.

The bridge also has a hole through the lower portion to receive the fastener screw, which is intended to key the bridge to the clamping system during seat adjustment, the head has a higher profile because of the "U" shaped bridge system and curved interface system, there are eight total components, there is a clamping head that is connected to a tube, and installing the seat is difficult because the fastener parts must be installed into the clamps and "U" shaped bridge after the seat rails are installed into the clamps and the bridge is placed between the rails. This makes it impossible to install the bridge onto the seat rails with the fastener installed because the fastener passes though the bridge and thus the bridge cannot twist or move out of the way.

Thus, it is desirable to have a seat assembly that is light weight, simple to manufacture, and simply for the rider to use, with adjustments for height, horizontal location, and angle.

OBJECTS OF THE INVENTION

In accordance with an embodiment of the invention, a seat post assembly has a bridge placed between saddle rails, where the bridge supports the rails such that a clamping mechanism can clamp the rails from the sides. The bridge engages with the clamping mechanism so that the bridge is keyed to the mechanism even when the saddle position and angle are adjusted. The bridge is in compression only, and thus can be extremely light weight.

In one embodiment, the assembly includes a seat post having an upper end that is secured to the saddle or seat, where the upper end has curved portion with two upwardly curved ends. The clamping mechanism, in one embodiment, has two opposing clamp portions with a curved groove that corresponds with the curved end of the seat post. The curved groove allows the clamps to be moved in an arc to adjust the angle of the seat without requiring beveled edges. Each clamp portion also includes a straight semi- cylindrical groove above the curved groove, where the semi-cylindrical groove fits onto the saddle rails. The semi-cylindrical grooves allow the seat to be adjusted frontward or backward horizontally along the seat rails. Each semi-cylindrical groove also has a notch or cut-out portion that engages with a corresponding protrusion on the bridge. This enables the bridge and clamping mechanism to move together for seat adjustment. Between the curved and semi-cylindrical grooves is a through hole that receives a single bolt for clamping the seat post to the rails for both angular and fore and aft adjustment.

The components of the seat post assembly are simple and inexpensive to manufacture. The light weight bridge and low number of components result in a light weight assembly, while still providing the necessary strength. The seat is easily installed and adjusted. In another embodiment, the seat post has a seat height identification system, which makes it extremely easy for the rider to always put the seat at the appropriate height, and easily change the marking (if necessary) after installing a new seat. There are a series of small depressions in the post. After the rider finds the correct seat height, the rider applies a small contrasting decal to the depression that is just above the bicycle frame seat tube clamp. Mountain bikers often lower their seat posts for difficult terrain, and this system makes it fast and easy to clamp the seat post back to the original preferred position when desired.

These and other features and advantages of the present invention will be more readily apparent from the detailed description of the embodiments set forth below taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows a clamping mechanism, a bridge, and a seat rail according to one embodiment of a seat post assembly of the present invention;

Fig. 2A shows a top portion of the seat post assembly of Fig. 1 without the clamp portions according to one embodiment;

Fig. 2B shows a clamp portion of the clamping mechanism of Fig. 1 according to one embodiment;

Fig. 3 shows the bridge of Fig. 1 secured to the seat rail;

Fig. 4 shows the clamping mechanism secured to the bridge and seat rail of Fig. 1;

Fig. 5 shows a perspective view of the seat post assembly with the clamping mechanism and bridge according to one embodiment;

Fig. 6 is a top view of the seat post assembly of Fig. 5;

Fig. 7 is a sectional view along line A-A of Fig. 6;

Fig. 8 shows a seat post assembly with adjustment markings according to one embodiment;

Fig. 9 shows the seat post assembly of Fig. 8 inserted into a frame of a bicycle for proper height adjustment;

Fig. 10 shows the seat post assembly of Fig. 8 inserted into a frame of a bicycle for improper height adjustment; Fig. 11 shows a seat post assembly according to another embodiment, where the seat post is offset from the clamping mechanism; and

Fig. 12 shows a side view of the base portion of the seat post in an offset position.

Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, wherein showings therein are for purposes of illustrating embodiments of the present disclosure and not for purposes of limiting the same. EMBODIMENTS OF THE INVENTION

Fig. 1 shows components of a seat post assembly 100 according to one embodiment of the present invention. Seat post assembly includes a seat post 102 secured to a clamping mechanism 104 and a bridge 106. Seat post assembly 100 clamps to a seat rail 108, which is attached to a bicycle saddle or seat (not shown). Referring also to Fig. 2A, clamping mechanism 104 includes a base portion 110 having upwardly curved ends 112 extending outward from a wall 114. In one embodiment, base portion 110 and seat post 102 are a unitary structure. In another embodiment, base portion 110 is press-fit into seat post 102.

Clamping mechanism 104 also comprises two opposing clamp portions 116. Referring also to Fig. 2B, each clamp portion 116 has an upwardly curved groove 118 corresponding to curved ends 112 of base portion 110. Groove 118 and curved ends 112 enable clamping mechanism 104 to be moved in an arc for changing the angle of the seat. Clamp portion 116 also has a straight semi-cylindrical groove 120 that fits into a tubular portion 122 of seat rail 108, which enables seat rail 108, and thereby the seat or saddle, to be moved up or back from seat post 102 to horizontally adjust the seat frontward or backward. Note that the "tubular" portion (or the rail) can be solid or hollow, and "tubular" as used herein does not require a solid tube. Along an upper area of each clamp portion 116, a notch 130 is formed along the interior. Notch 130, as will be described below with reference to bridge 106, enables clamping mechanism 104 to move with bridge 106. A through hole 124 between groove 118 and groove 120 accommodates a bolt 126 that can be tightened or loosened to secure or loosen clamping mechanism 104 to or from seat rail 108.

In one embodiment, bolt 126 has a first piece 702 with a threaded male end and a second piece 704 with a matching threaded female end (see also Fig. 7). First piece 702 has a smooth head 706 that allows first piece 702 to be rotated for tightening and loosening. Smooth head 706 has an opening 708 to allow a user to tighten or loosen clamping mechanism 104 with a tool, such as an Allen wrench or screwdriver. Thus, opening 708 can be hexagonal, a slit, bisecting slits, or other means. Second piece 704 has a head 710 that is secured against one of clamp portions 116, such that when first piece 702 is turned, second piece 704 remains stationary. In one embodiment, second piece 704 has a notch that corresponds to a slot 128 (see Fig. 2B) in through hole 124 of one of clamp portions 116. Thus, when second piece 704 is pushed into through hole 124, the notch can be fitted into slot 128 to prevent rotational movement of the second piece. The other clamp portion does not have the slot to allow free rotation of first piece 702. Both clamp portions 116 may have a conical bore 712 that allows the head of the first and second piece of the bolt to be flush or recessed with the clamp portions when tightened. Note that other securing structures and mechanisms may also be suitable. Both first and second pieces 702 and 704 have a portion that extends through each respective through hole 124, such that the threaded male end engages with the corresponding female end between an opening of the two clamp portions 116. In another embodiment, instead of a notch, second piece 704 has a turning means like piece 702. In that case, either both pieces 702 and 704 can be turned simultaneously (oppositely), or one or the other piece can be held with a tool while the other is turned. Seat post assembly 100 also includes bridge 106, which enables clamping mechanism 104 to be securely fastened to seat rail 108. Bridge 106, in one embodiment, is a unitary structure having opposing curved surfaces 132 that fit or "snap" between seat rail 108 into tubular portions 122. Bridge also has a raised portion 134 with a ridge 136 that is approximately the same length as the length of notch 130 of clamp portion 116. Ridge 136 engages within notch 130, so that bridge 106 and clamping mechanism 104 can move laterally together along seat rail 108. One function of bridge 106 is to provide an opposing force to the one applied by clamp portions 116. As such, bridge 106 is in almost pure compression and thus can be made using a minimum of light weight materials, such as aluminum, carbon fiber, or composite material. With the combination of components that are both light weight and few in number, seat post assembly 100 can be light and easy to make and use.

Fig. 3 shows bridge 106 secured to tubular portions 122 of seat rail 108. Seat rail 108, even when connected to a seat or saddle, is flexible such that tubular portions 122 can be pushed outward to "snap" bridge 106 therebetween. Note that curved surfaces 132 (see Fig. 1) fit flush with tubular portions 122, with ridge 136 (see Fig. 1) extending above tubular portions 122. Tubular portions 122 are typically a similar distance apart, but if tubular portions 122 of a particular saddle are slightly closer together, then bridge 106 will push the tubular portions apart to the desired distance. If tubular portions 122 are slightly farther apart than usual, then clamp portions 116 will push the tubular portions together until correctly fitting bridge 106. Most tubular portions have a diameter of 7mm; however bridge 106 and clamps 116 can easily be designed to fit tubular portions of other diameters or shapes. The smooth surfaces of curved surfaces 132 and tubular portions 122 enable bridge 106 to slide along tubular portions 122 for positioning.

Fig. 4 shows clamping mechanism 104 and seat post 102 secured to bridge 106 and seat rail 108. In operation, bolt 126 is loosened sufficiently to allow clamp portions 116 to engage tubular portions 122. Once engaged, bolt 126 is tightened, such as with an Allen wrench, screwdriver, or suitable tool, and clamp portions 116 are aligned with bridge 106. In particular, ridge 136 of the bridge is aligned with notch 130 of the clamp portions. Bolt 126 is further tightened to force ridges 136 into notches 130, but not to the point where bolt 126 cannot be further tightened. At this point, seat rail 108 (with attached seat) can be moved along an arc via the arc shaped groove of the clamp portions and the arc shaped curved ends of the base portion, enabling the seat angle to be adjusted. In addition, seat rail 108 can be moved forward and backward along via the tubular portions of the seat rail and the semi-cylindrical grooves of the clamp portions, enabling lateral seat position to be adjusted. Because ridges 136 and notches 130 are engaged, bridge 106 and clamping mechanism 106 move together during seat adjustment. Once the seat is adjusted to a desired position, bolt 126 can be tightened to secure the seat to the seat post.

Fig. 5 is a perspective view of seat post assembly 100 without the seat rail being attached. As can be seen, the curved surface of the bridge and the curved surface of the clamp portions form a cylindrical opening through which the tubular portions of the seat rail can be secured. Also seen are the ridges of the bridge engaging with the notches of the clamp portions to allow the bridge to move with the clamping mechanism.

Fig. 6 is a top view of seat post assembly 100, which shows raised portion 134 of bridge 106, clamp portions 116, and bolt 126. Fig. 6 also shows sectional line A- A, which represents the view of Fig. 7. Fig. 7, as mentioned above, is a sectional view along line A-A of Fig. 6. Curved surface 132 of bridge 106 and groove 120 of clamp portion 116 form a cylindrical opening 714 for engaging the seat rails. The bolt with first piece 702 and second piece 704 secures clamp portions 116 against the seat rails and forces tubular portions 122 of the seat rail against bridge 106.

There are many advantages to this seat post assembly. For example, only a single bolt clamps the seat rails and allows both angular and fore and aft adjustment for a simple clamping mechanism, each component is simple to manufacture, the design uses material more efficiently, e.g., less material for similar strength, which allows a lighter seat post, installation of the seat rail into the seat post clamp is very easy, and the design allows extremely efficient use of material for a light weight seat post. More particular, the presently described seat post assembly provides numerous advantages over the prior art seat post disclosed in the '391 patent. These include: 1) no requirement of a curved fastener interface; 2) no requirement of beveled edges; 3) no requirement of a washer (curved or otherwise); 4) a straight bridge which is far more efficient for the compression loads (allowing use of less material and is lighter); 5) fewer total parts for a simpler design and lower cost to manufacture; 6) lower profile; 7) the head and tube integrated as a single unit (which is lighter and less expensive and stronger); 8) the bridge is keyed to the clamps via simple engagement contours; and 9) installation is easier because the fastener is never removed from the clamps, and in fact, installation only requires the bridge to be slid into position, and then the rails will "snap" into the clamps (when the fastener is adjusted to the correct position), and then the fastener tightened. Adjustment is accomplished simply by loosening the fastener and moving the seat to the desired fore and aft position, and to the desired angle, and then the fastener tightened again.

Fig. 8 shows another embodiment of a seat post assembly 800. Assembly 800 includes seat post 102 that slides into an opening of a bicycle frame (not shown). A clamping mechanism on the frame allows seat post 102 to be set to a desired height for the rider. Seat post 102 has a series of indentations 802 along a length of the post. The position of the indentations, the total length of the indentations, and the separation between individual indentations may vary. For example, the position may be determined by the length of the seat post, the total length may be determined by the range of heights practicable for the bicycle, and the separation may be determined by the desired incremental adjustments in height. To adjust to a desired height, the rider may loosen the clamp, and move the seat to a desired height. The desired height can be determined through trial and error test riding, or with the help of a bicycle fit specialist. At that height, the rider or user can place a decal 804 over the indentation directly above the frame tube. Decal 804 can be a contrasting color to the seat post for easy visual identification. Decal 804 may be removable or of other marking forms, such as paint or a marker, to indicate the desired indentation.

Fig. 9 shows a correctly adjusted seat post height. Decal 804 is just above a clamp 902 that secures the seat post to a frame 904. In one use, the rider is initially riding the bicycle at a higher seat position, such as when going through less extreme terrain in a mountain bike. When the terrain becomes more extreme, the rider may want to lower the seat, which is safer but less efficient for pedaling. This can be easily accomplished by loosening the clamp, such as with a finger latch, depressing the seat, and then tightening the clamp. Then, when the riders wants to return the seat to the more efficient raised position, the rider loosens the clamp, raises the seat until decal 804 is just above clamp 902, and tightens the clamp. The decal allows the rider to simply feel along the series of indentations until encountering the decal, resulting in non-visual seat adjustment. If the decal is of a contrasting color, the rider can easily adjust the seat even in low light conditions by visual inspection.

Fig. 10 shows the seat post at a higher than desired position. The rider simply moves the seat post down until the decal or marker is just above the clamp.

Such a seat height adjusting system can also be used when a rider changes from one seat to another, which can result in a substantial difference in height between the rails of the saddle and the seat area and require adjustments to the seat post height. Also, a change in bicycle frame or shoes or pedals or crank arms can similarly affect where the seat post should be marked.

Thus, the seat post adjusting system can enable fast and easy clamping of the seat post back to the original preferred position when desired. This system is easy to see, even with limited light such as when night riding. In very dark conditions, the rider can feel the depressions, count them, and know approximately where to clamp the seat post entirely by feel.

The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. For example, the clamping mechanism and base portion may be offset from the seat post, as shown in Figs. 11 and 12. Furthermore, the rail has been described as tubular or cylindrical. However, the rail may not be 100% cylindrical, but may have flattened portions, although still be mostly cylindrical. The clamps and bridge may be slightly modified to accommodate different shapes, so the curved surface of the bridge and the semi-cylindrical groove of the clamps need to be completely cylindrical or a smooth curve. Having thus described embodiments of the present disclosure, persons of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.

Claims

1. A seat post assembly, comprising:

a base comprising a first and a second upwardly curved end located on opposite sides of the base;

a first clamp movable along the first upwardly curved end, the first clamp comprising an upwardly curved groove, a straight semi-cylindrical groove above the curved groove, and an opening between the curved groove and the semi- cylindrical groove;

a second clamp movable along the second upwardly curved end, the second clamp comprising an upwardly curved groove, a straight semi-cylindrical groove above the curved groove, and an opening between the curved groove and the semi- cylindrical groove, wherein the semi-cylindrical grooves of the first and second clamp fit onto tubular rails of a seat rail;

a bolt comprising a male end and a female end to secure the first and second clamp against the base and seat rail; and

a bridge comprising opposing curved surfaces adapted to engage and fit between the tubular rails.

2. The seat post assembly of claim 1, wherein the first and second clamps each have a notch along a top portion of the semi-cylindrical groove and the bridge has opposing ridges above the curved surfaces of the bridge, wherein each ridge fits into the notch.

3. The seat post assembly of claim 1, wherein the bridge is aluminum or a composite material.

4. The seat post assembly of claim 1, wherein the base is unitary with a seat post.

5. The seat post assembly of claim 1, wherein the male end extends through one of the openings and the female end extends through another one of the openings.

6. The seat post assembly of claim 1, wherein the openings are cone-shaped and the ends of the bolt have a tapered surface corresponding to the openings.

7. The seat post assembly of claim 1, wherein one of the ends of the bolt has an opening to rotate the bolt.

8. The seat post assembly of claim 7, wherein the opening is adapted to fit an Allen wrench or screwdriver.

9. The seat post assembly of claim 1, further comprising a seat post having a vertical series of indentions for use in adjusting the height of the seat rail.

10. The seat post assembly of claim 9, further comprising a marker for marking at least one of the indentations to designate a desired height.

11. The seat post assembly of claim 10, wherein the marker is a removable decal.

12. The seat post assembly of claim 1, wherein the base is offset from a seat post.

13. The seat post assembly of claim 1, wherein one of the clamps has a slot in the opening and one of the ends of the bolt has a notch corresponding to the slot.

14. The seat post assembly of claim 1, wherein the upwardly curved grooves of the first and second clamps have a substantially U-shaped cross section.

15 The seat post assembly of claim 1, wherein the bridge is substantially annular-shaped.

16. The seat post assembly of claim 1, wherein the bridge has opposing ridges both above and below the curved surfaces of the bridge to aid in securing the tubular rails.

17. The seat post assembly of claim 1, wherein the base is offset from a seat post.

18. The seat post assembly of claim 17, wherein the offset is along a longitudinal direction of a seat.

19. A seat post assembly for securing a seat to a frame, comprising:

a seat post;

a base connected to the seat post, the base comprising a first and a second upwardly curved end located on opposite sides of the base;

a first clamp movable along the first upwardly curved end, the first clamp comprising an upwardly curved groove, a straight semi-cylindrical groove above the curved groove having an opening along a top portion of the semi-cylindrical groove, and a hole between the curved groove and the semi-cylindrical groove; a second clamp movable along the second upwardly curved end, the second clamp comprising an upwardly curved groove, a straight semi-cylindrical groove above the curved groove having an opening along a top portion of the semi- cylindrical groove, and a hole between the curved groove and the semi-cylindrical groove, wherein the semi-cylindrical grooves of the first and second clamp fit onto tubular rails of a seat rail and enable the fore and aft position of the seat to be adjusted and wherein the curved ends and curved grooves enable the angle of the seat to be adjusted;

a bridge comprising opposing curved surfaces adapted to snap between the tubular rails and opposing ridges above the curved surfaces, wherein the ridges fit into the opening of the first and second clamps to enable the bridge and clamps to move together along the tubular rails.

20. The seat post assembly of claim 19, wherein the seat post and the base are a unitary structure.

21. The seat post assembly of claim 19, wherein the bridge is aluminum or a composite material.

22. The seat post assembly of claim 19, wherein the male end extends through one of the holes and the female end extends through another one of the holes.

23. The seat post assembly of claim 19, wherein the holes are cone-shaped and the ends of the bolt have a tapered surface corresponding to the holes.

24. The seat post assembly of claim 19, wherein one of the ends of the bolt has an opening to rotate the bolt.

25. The seat post assembly of claim 24, wherein the opening is adapted to fit an Allen wrench or screwdriver.

26. The seat post assembly of claim 19, wherein the seat post has a vertical series of indentions for use in adjusting the height of the seat.

27. The seat post assembly of claim 26, further comprising a marker for marking at least one of the indentations to designate a desired height.

28. The seat post assembly of claim 22, wherein the marker is a removable decal.

29. The seat post assembly of claim 19, wherein the base is offset from the seat post.

30. The seat post assembly of claim 19, wherein one of the clamps has a slot in the hole and one of the ends of the bolt has a notch corresponding to the slot.

31. A seat post for a bicycle, comprising:

a vertical series of indentations along at least a partial length of the seat post; and

a marker for identifying at least one of the indentations for adjusting the height of a seat.

32. The seat post of claim 31, wherein the marker is a removable decal.

33. The seat post of claim 31, wherein the marker is a contrasting color to the seat post.