Bicycle seat post

A seat post is disclosed. The seat post includes a pneumatic cylinder, a hollow pneumatic piston, a gap, a seal, a hydraulic cylinder, a hollow hydraulic piston, and a valve. The gap exists between the pneumatic cylinder and the pneumatic piston and communicates with the inside of the pneumatic piston. The seal is disposed at the pneumatic cylinder for sealing the gap. The hydraulic cylinder is disposed in the pneumatic piston and communicates with the inside of the pneumatic piston. One end of the hydraulic piston passes through pneumatic piston and is inserted into the hydraulic cylinder. The other end is disposed in the pneumatic cylinder and communicates with the inside of the pneumatic cylinder. The valve connects the pneumatic piston and the hydraulic cylinder for opening or closing the communication between the pneumatic piston and the hydraulic cylinder.

RELATED APPLICATIONS

The application claims priority to Taiwan Application Serial Number 99220386, filed Oct. 21, 2010, which is herein incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a connection between a seat and a bicycle frame. More particularly, the present disclosure relates to a seat post.

2. Description of Related Art

A seat post is a tube for fixing a seat on a bicycle. More specifically, the seat post is telescopic for changing the height of the seat to fit users. Furthermore, the seat post can use threads, clamp, or pneumatic cylinder to fix the height of the seat.

As to the pneumatic cylinder, the seat post has a control lever for actuating the pneumatic cylinder. The seat post will be extended when the pneumatic cylinder is actuated and the user does not sit on the seat yet. The seat post will be contracted when the pneumatic cylinder is actuated and the user is sitting on the seat. The height of the seat is fixed when the pneumatic cylinder is shut down. Obviously, the adjusting speed of the pneumatic cylinder is better than threads and clamp.

However, the drawback of the pneumatic cylinder is that the pneumatic cylinder is easily to be compressed when the pneumatic cylinder is shut down and under a force. In other words, the height of the seat is changed when the user is sitting on the seat and compresses the pneumatic cylinder, even if the height of the seat is fixed. Therefore, some strength of the user for pedaling will transmit to the pneumatic cylinder and compress the pneumatic cylinder. It wastes the work of the user for pedaling. As above, it is difficult to increase the fixing stiffness of the seat post.

SUMMARY

The present disclosure provides a seat post for a bicycle. The seat post uses hydraulic pressure and gas pressure for resisting the compression and maintaining the adjusting speed.

According to one embodiment of the present disclosure, a seat post includes a first piston set, a second piston set, a valve, a liquid, and a gas. The first piston set includes a first cylinder, a first hollow piston, a gap, and a seal. The first cylinder connects to a frame of a bicycle. One end of the first hollow piston is inserted into the first cylinder and has a through hole. The other end of the first hollow piston connects to a seat of the bicycle. The gap exists between the inside of the first cylinder and the outside of the first hollow piston and communicates with the inside of the first hollow piston. The seal is disposed at the first cylinder for sealing the gap. The second piston set includes a second cylinder and a second hollow piston. The second cylinder is disposed in the first hollow piston and communicates with the inside of the first hollow piston. The cross-sectional area of the inside of the second cylinder is the same as the cross-sectional area of the gap. The gap, the inside of the first hollow piston, and the second cylinder composes a first chamber. One end of the second hollow piston passes through the through hole and is inserted into the second cylinder. The other end of the second hollow piston is disposed in the first cylinder. The inside of the second hollow piston communicates with the inside of the first cylinder. The inside of the first cylinder and the second hollow piston composes a second chamber. The valve connects the first hollow piston and the second cylinder for opening or closing the communication between the first hollow piston and the second cylinder. The liquid is stored in the first chamber. The gas is stored in the second chamber.

According to another embodiment of the present disclosure, a seat post includes a pneumatic cylinder, a hollow pneumatic piston, a gap, a seal, a hydraulic cylinder, a hollow hydraulic piston, a valve, and a locking hub. The pneumatic cylinder connects to a frame of a bicycle. The hollow pneumatic piston is received in the pneumatic cylinder and includes a through hole. One end of the hollow pneumatic piston connects to a seat of the bicycle. A gap exists between the outside of the hollow pneumatic piston and the inside of the pneumatic cylinder and communicates with the inside of the hollow pneumatic piston. The seal is disposed at the pneumatic cylinder for sealing the gap. The hydraulic cylinder is disposed in the hollow pneumatic piston and communicates with the inside of the hollow pneumatic piston. The cross-sectional area of the inside of the hydraulic cylinder is the same as the cross-sectional area of the gap. One end of the hollow hydraulic piston passes through the through hole and is in the hydraulic cylinder. The other end of the hollow hydraulic piston is disposed in the pneumatic cylinder. The inside of the hollow hydraulic piston communicates with the inside of the pneumatic cylinder. The valve connects the hollow pneumatic piston and the hydraulic cylinder for opening or closing the communication between the hollow pneumatic piston and the hydraulic cylinder. The locking hub includes two planes. The two planes are respectively disposed at the inside of the hollow pneumatic piston and the outside of the hollow hydraulic piston, wherein the two planes resist against each other.

According to yet another embodiment of the present disclosure, a seat post includes a pneumatic cylinder, a hollow pneumatic piston, a gap, a seal, a hydraulic cylinder, a hollow hydraulic piston, a valve, and a locking hub. The pneumatic cylinder connects to a frame of a bicycle. The hollow pneumatic piston is received in the pneumatic cylinder and includes a through hole. One end of the hollow pneumatic piston connects to a seat of the bicycle. A gap exists between the outside of the hollow pneumatic piston and the inside of the pneumatic cylinder and communicates with the inside of the hollow pneumatic piston. The seal is disposed at the pneumatic cylinder for sealing the gap. The hydraulic cylinder is disposed in the hollow pneumatic piston and communicates with the inside of the hollow pneumatic piston. The cross-sectional area of the inside of the hydraulic cylinder is the same as the cross-sectional area of the gap. One end of the hollow hydraulic piston passes through the through hole and is in the hydraulic cylinder. The other end of the hollow hydraulic piston is disposed in the pneumatic cylinder. The inside of the hollow hydraulic piston communicates with the inside of the pneumatic cylinder. The valve connects the hollow pneumatic piston and the hydraulic cylinder for opening or closing the communication between the hollow pneumatic piston and the hydraulic cylinder. The locking hub includes at least one groove and at least one rotating spindle. The groove is located on one of the outside of the hollow hydraulic piston and the inside of the hollow pneumatic piston, and the rotating spindle is located on the other of them.

DETAILED DESCRIPTION

FIG. 1is a plan view of a seat post according to one embodiment of the present disclosure.FIG. 2is a cross-sectional view viewed along line2-2ofFIG. 1. The seat post includes a first piston set100, a second piston set200, a valve300, a liquid400, and a gas500. The first piston set100includes a first cylinder110, a first hollow piston120, a gap140, and a seal130. The first cylinder110connects to a frame (not shown) of a bicycle (not shown). One end121of the first hollow piston120is inserted into the first cylinder110and has a through hole122. The other end123of the first hollow piston120connects to a seat (not shown) of the bicycle. The gap140exists between the inside of the first cylinder110and the outside of the first hollow piston120and communicates with the inside of the first hollow piston120. The seal130is disposed at the first cylinder110for sealing the gap140. The second piston set200includes a second cylinder210and a second hollow piston220. The second cylinder210is disposed in the first hollow piston120and communicates with the inside of the first hollow piston120. The cross-sectional area of the inside of the second cylinder210is the same as the cross-sectional area of the gap140. The gap140, the inside of the first hollow piston120, and the second cylinder210composes a first chamber. One end221of the second hollow piston220passes through the through hole122and is inserted into the second cylinder210. The other end222of the second hollow piston220is disposed in the first cylinder110. The inside of the second hollow piston220communicates with the inside of the first cylinder110. The inside of the first cylinder110and the second hollow piston220composes a second chamber. The valve300connects the first hollow piston120and the second cylinder210for opening or closing the communication between the first hollow piston120and the second cylinder210. The liquid400is stored in the first chamber. The gas500is stored in the second chamber.

The second cylinder210moves toward the second hollow piston220and presses the liquid400when the valve300is closed and the user is sitting on the seat. The liquid400in the second cylinder210cannot flow into the gap140and inside of the first hollow piston120because the valve300is closed. Furthermore, the first hollow piston120and the second cylinder210barely move, because the compressibility of the liquid400is less than the gas500. Therefore, the compression resistance of the seat post is improved.

FIG. 3illustrates the seat post ofFIG. 2in one operating mode. The second cylinder210moves toward the second hollow piston220and presses the liquid400into the gap140through the inside of the first hollow piston120, when the valve300is opened and the user is sitting on the seat. The moving distance of the second cylinder210and the first hollow piston120are the same as the increased distance of the gap140because of the same cross-sectional area of the inside of the second cylinder210and the gap140. Therefore, the second cylinder210and the first hollow piston120move synchronically for contracting the seat post, lowering the height of the seat, and compressing the gas500in the first cylinder110.

FIG. 4illustrates the seat post ofFIG. 3in another operating mode. The compressed gas500in the first cylinder110pushes the first hollow piston120and the second cylinder210back when the valve300is opened and the user leaves the seat. Furthermore, the distance of the gap140is decreased for pushing the liquid400back to the inside of the second cylinder210, extending the seat post, and raising the height of the seat.

Therefore, the height of the seat is raised when the valve300is opened and the user leaves the seat. On the contrary, the height of the seat is lowered when the valve300is opened and the user is sitting on the seat. The height of the seat is fixed when the valve300is closed. It is obvious that the seat post maintains the adjusting speed of the seat post.

As shown inFIG. 2, the valve300includes a base310and a restoring rod320. The base310connects to the first hollow piston120and the second cylinder210. The base310includes a through hole311. One end321of the restoring rod320passes through the through hole311of the base310for opening or closing the communication between the first hollow piston120and the second cylinder210. The other end322of the restoring rod320protrudes from the base310. The end321of the restoring rod320opens the communication between the first hollow piston120and the second cylinder210when the end322of the restoring rod320is pushed. On the contrary, the end321of the restoring rod320is restored and closes the communication between the first hollow piston120and the second cylinder210when the pushing force releases the end322of the restoring rod320.

The seat post further includes a control lever600. The control lever600is pivoted on the first hollow piston120for operating the valve300. One end610of the control lever600pushes the restoring rod320. The other end620of the control lever600is operated by the user. The valve300is opened when the user operates the control lever600to push the restoring rod320. On the contrary, the restoring rod320and the control lever600are restored and the valve300is closed when the user releases the control lever600.

FIG. 5is a cross-sectional view of a seat post according to another embodiment of the present disclosure.FIG. 6is a cross-sectional view viewed along line6-6ofFIG. 5. The seat post includes a pneumatic cylinder710, a hollow pneumatic piston720, a gap730, a seal130, a hydraulic cylinder810, a hollow hydraulic piston820, a valve300, and a locking hub900. The pneumatic cylinder710is considered as the first cylinder110. The hollow pneumatic piston720is considered as the first hollow piston120. The hydraulic cylinder810is considered as the second cylinder210. The hollow hydraulic piston820is considered as the second hollow piston220. The pneumatic cylinder710connects to a frame of a bicycle. The hollow pneumatic piston720is received in the pneumatic cylinder710and includes a through hole721. One end of the hollow pneumatic piston720connects to a seat of the bicycle. A gap730exists between the outside of the hollow pneumatic piston720and the inside of the pneumatic cylinder710and communicates with the inside of the hollow pneumatic piston720. The seal130is disposed at the pneumatic cylinder710for sealing the gap730. The hydraulic cylinder810is disposed in the hollow pneumatic piston720and communicates with the inside of the hollow pneumatic piston720. The cross-sectional area of the inside of the hydraulic cylinder810is the same as the cross-sectional area of the gap730. One end821of the hollow hydraulic piston820passes through the through hole721and is in the hydraulic cylinder810. The other end822of the hollow hydraulic piston820is disposed in the pneumatic cylinder710. The inside of the hollow hydraulic piston820communicates with the inside of the pneumatic cylinder710. The valve300connects the hollow pneumatic piston720and the hydraulic cylinder810for opening or closing the communication between the hollow pneumatic piston720and the hydraulic cylinder810. The locking hub900includes two planes910. The two planes910are respectively disposed at the inside of the hollow pneumatic piston720and the outside of the hollow hydraulic piston820, wherein the two planes910resist against each other.

The two planes910are disposed at the inside of the hollow pneumatic piston720and the outside of the hollow hydraulic piston820directly. Thus, the outside of the hollow hydraulic piston820and the inside of the hollow pneumatic piston720resist against each other directly. Therefore, the hollow hydraulic piston820and the hollow pneumatic piston720are only axially moved according to the locking hub900. Furthermore, the pneumatic cylinder710cannot rotate about the hollow pneumatic piston720, because the hollow pneumatic piston720connects to the hydraulic cylinder810, and the hollow hydraulic piston820connects to the pneumatic cylinder710. Therefore, the operation of the seat post includes extension and contraction except for rotation. Thus, the seat post disposed on the bicycle can fix the horizontal angle of the seat.

As shown inFIG. 5, the valve300is the same as that shown inFIG. 2. The base310of the valve300connects to the hollow pneumatic piston720and the hydraulic cylinder810. The restoring rod320of the valve300passes through the base310for opening or closing the communication between the hollow pneumatic piston720and the hydraulic cylinder810.

The seat post further includes a control lever600, and the control lever600is the same as that shown inFIG. 2. The control lever600is pivoted on the hollow pneumatic piston720for operating the valve300.

FIG. 7illustrates the seat post ofFIG. 5in another embodiment of the present disclosure.FIG. 8is a cross-sectional view viewed along line8-8ofFIG. 7. The hollow pneumatic piston720includes a cushion722positioned in the through hole721of the inside of the hollow pneumatic piston720. The two planes910are respectively disposed at the cushion722in the inside of the hollow pneumatic piston720and the outside of the hollow hydraulic piston820. The cushion722resists against the hollow hydraulic piston820. Furthermore, the cushion722is made of anti-abrasion material, such as copper, for increasing the lifetime. Additionally, the shape of the cushion722is cylindrical. The cushion722reduces the friction between the hydraulic cylinder810and the pneumatic piston as the roller when the hydraulic cylinder810and the pneumatic piston move relative to each other.

FIG. 9is a cross-sectional view of a seat post according to another embodiment of the present disclosure.FIG. 10is a cross-sectional view viewed along line10-10ofFIG. 9. The seat post shown inFIG. 9is similar to that shown inFIG. 5. The difference betweenFIG. 9andFIG. 5is that the locking hub900ofFIG. 9includes at least one groove920and at least one rotating spindle930. The groove920is located on one of the outside of the hollow hydraulic piston820and the inside of the hollow pneumatic piston720. The rotating spindle930is located on the other of them and received in the groove920.

In detail, the locking hub900includes two grooves920. The two grooves920are respectively located on the outside of the hollow hydraulic piston820and the inside of the through hole721in the inside of the hollow pneumatic piston720. The rotating spindle930is positioned between the two grooves920.

FIG. 11illustrates the seat post ofFIG. 10in another embodiment of the present disclosure. The locking hub900includes only one groove920. The groove920is located on the outside of the hollow hydraulic piston820and the rotating spindle930is fixed at the inside of the through hole721in the inside of the hollow pneumatic piston720, or the groove920is located on the inside of the through hole721in the inside of the hollow pneumatic piston720and the rotating spindle930is fixed at the outside of the hollow hydraulic piston820. In this embodiment, the rotating spindle930is fixed at the outside of the hollow hydraulic piston820. All of the locking hubs900ofFIG. 9have the same advantage as the locking hub900ofFIG. 5.

As shown inFIG. 9, the valve300is the same as that shown inFIG. 5. The seat post further includes a control lever600the same as that shown inFIG. 5.

Any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. §112, 6th paragraph. In particular, the use of “step of” in the claims is not intended to invoke the provisions of 35 U.S.C. §112, 6th paragraph.