Patent Description:
The height of the bicycle saddle will affect comfort and safety of riding. The current structure is equipped with an adjustable seatpost that can be operated to adjust the height of the saddle according to the rider's body shape, the rider's habits and the riding environment, such that the adjustable seatpost allows the rider to ride in the correct posture, thereby improving riding comfort and safety.

However, the inner tube of the adjustable seatpost can be lowered to achieve the effect of saving storage space. After the inner tube is lowered, the height of the inner tube needs to be re-adjusted if the rider would like to use it on the next ride. The rider may spend a lot of time looking for a suitable height of the saddle. This will cause inconvenience and trouble to the rider.

<CIT>, which shows the preamble of claim <NUM>, describes a liftable seatpost of a bicycle. As shown in <FIG> and <FIG> of the aforesaid prior art, the bushing <NUM> includes an upper sleeve <NUM> and a lower sleeve <NUM>. The bottom end of the upper sleeve <NUM> has an insertion slot <NUM>, and the top end of the lower sleeve <NUM> has an insertion portion <NUM>. The upper sleeve <NUM> is sleeved on the lower sleeve <NUM> in a way that the insertion slot <NUM> of the upper sleeve <NUM> is inserted into the insertion portion <NUM> of the lower sleeve <NUM>. However, the outer surface of the upper sleeve <NUM> protrudes out of the outer surface of the lower sleeve <NUM>. This cause that the structural volume of the liftable seatpost <NUM> at the position corresponding to the bushing <NUM> is relatively large, such that the visual appearance of the entire liftable seatpost10 is less simple and neat, resulting in that product appearance of the liftable seatpost <NUM> is slightly inferior. On the other hand, in the process of adjusting the overall height of the liftable seatpost <NUM>, the protrusion <NUM> of the inner tube <NUM> is abutted against one of the limiting grooves <NUM> of the lower sleeve <NUM>. When the protrusion <NUM> is abutted against one of the limiting grooves <NUM>, the stress is transmitted from the insertion portion <NUM> of the lower sleeve <NUM> to the insertion grove <NUM> of the upper sleeve <NUM> so as to be concentrated between the insertion portion <NUM> and the insertion slot <NUM>. Under long-term use, there may be wear between the upper and lower sleeves <NUM>, <NUM>, which shortens the service life of the entire bushing <NUM>.

It is a primary objective of the present invention to provide a liftableseatpost, which has a better appearance design and reduces wear between upper and lower sleeves.

To attain the above objective, the total height adjustable seatpost of the present invention comprises an outer tube, an inner tube, and a bushing. The inner tube is movably disposed upwards and downwards in the outer tube. The top end of the inner tube is located outside the outer tube, and the bottom end of the inner tube is received in the outer tube. The outer surface of the bottom end of the inner tube has a protrusion. The bushing is disposed between the inner tube and the outer tube and has an upper sleeve and a lower sleeve. The upper sleeve is rotatably disposed to the top end of the outer tube, and the bottom end of the upper sleeve has an upper baffle ring provided with a first engaging portion at a bottom end thereof. The lower sleeve is received in the outer tube and disposed to the bottom end of the upper sleeve. The bottom end of the lower sleeve has a lower baffle ring provided with a second engaging portion at the top end thereof engaged with the first engaging portion of the upper baffle ring, so that the upper sleeve and the lower sleeve are moved synchronously. The top edge of the lower baffle ring of the lower sleeve is abutted against the bottom edge of the upper baffle ring of the upper sleeve. The lower sleeve has a limiting portion at the bottom end thereof abutted against the protrusion of the inner tube. In addition, the outer surface of the upper baffle ring of the upper sleeve is flushed with the outer surface of the lower baffle ring of the lower sleeve.

It can be understood from the above illustration that since the outer surface of the upper baffle ring of the upper sleeve is flushed with the outer surface of the lower baffle ring of the lower sleeve, i.e., the outer surface of the upper baffle ring does not protrude out of the outer surface of the lower baffle ring, the structural volume of the liftable seatpost at the position corresponding to the bushing can be designed smaller without protruding too much from the outer surface of the outer tube, such that the overall appearance is simpler, neater and has a better appearance. On the other hand, since the top edge of the lower baffle ring of the lower sleeve is abutted against the bottom edge of the upper baffle ring of the upper sleeve, when the protrusion of the inner tube is abutted against the limiting portion of the lower sleeve, the stress generated from the protrusion can be effectively distributed through the full abutment between the top edge of the lower baffle ring and the bottom edge oof the upper baffle ring, such that wear between the upper and lower sleeves can be reduced.

In one of the aspects, at least one of the first and second engaging portions is a concave hole or bump, i.e., the first engaging portion is a concave hole and the second engaging portion is a bump, or the first engaging portion is a bump and the second engaging portion is a concave hole. In some case, the lower sleeve can be made of flexible material so as to allow the second engaging portion to be slightly elastically deformed for engaging with the first engaging portion conveniently.

In another aspect, the first engaging portion can be designed to have a small diameter section and a large diameter section located above the small diameter section and integrally connected with the small diameter section. In this way, the lower sleeve is not easy to detach from the upper sleeve.

In another aspect, the hardness of the upper sleeve can be designed to be greater than the hardness of the lower sleeve. For example, the upper sleeve is made of metal and the lower sleeve is made of plastic. In this way, the upper sleeve can be used to bear the stress applied by the protrusion of the inner tube.

In another aspect, the inner surface of the upper baffle ring of the upper sleeve is flushed with the inner surface of the lower baffle ring of the lower baffle ring. In this way, the upward and downward movement of the inner tube can be smoother.

In another aspect, the upper sleeve further includes an annular main body disposed above the upper baffle ring and connected with the upper baffle ring. A backing ring is disposed in the annular main body and located between the upper sleeve and the inner tube for reducing friction between the upper sleeve and the inner tube.

In another aspect, the outer tube further includes a plurality of positioning slots arranged equiangularly at the top end of the outer tube. The upper sleeve further has an indicating flange disposed in one of the positioning slots. In this way, the rider can easily know the preset overall height of the bushing.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

The technical content and features of the present invention will be described in detail by the following embodiment in coordination with the figures. The directional terms mentioned in the content of the specification, such as 'upper', 'lower', 'in', 'out', 'top', and 'bottom', are just for illustrative description on the basis of normal usage direction, not intended to limit the claimed scope.

Referring to <FIG>, the liftable seatpost <NUM> of the present invention comprises an outer tube <NUM>, an inner tube <NUM>, a sealing component <NUM>, and a bushing <NUM>.

The top end of the inner tube <NUM> is located outside the outer tube <NUM> and equipped with a clamping seat <NUM> for mounting a saddle (not shown). The bottom end of the inner tube <NUM> is penetrated into the outer tube <NUM> through the top end of the outer tube <NUM>. In addition, the outer surface of the bottom end of the inner tube <NUM> has three straight protrusions <NUM> (actually, at least one is sufficient, as shown in <FIG>, <FIG>, and <FIG>). The three protrusions <NUM> are arranged in an equally-spaced manner relative to the axis of the inner tube <NUM>.

As shown in <FIG> and <FIG>, a pneumatic cylinder <NUM> is disposed in the outer tube <NUM> and the inner tube <NUM>, and a trigger <NUM> is provided at the bottom of the outer tube <NUM>. When the trigger <NUM> is driven by a controller (not shown) to turn on the pneumatic cylinder <NUM>, the inner tube <NUM> can be lifted or lowered relative to the outer tube <NUM>. If the top end of the inner tube <NUM> does not bear the weight of the rider, the inner tube <NUM> will be lifted relative to the outer tube <NUM>, but if the top end of the inner tube <NUM> bears the weight of the rider, the inner tube <NUM> will be lowered relative to the outer tube <NUM>.

As shown in <FIG> and <FIG>, the sealing element <NUM> includes a cap <NUM> and a sealing member <NUM>. The cap <NUM> is screwed to the top end of the outer tube <NUM>. The sealing member <NUM> is sleeved on the inner tube <NUM> and pressed by the cap <NUM> to force against the outer surface of the inner tube <NUM>, thereby filling a gap between the outer tube <NUM> and the inner tube <NUM>. In addition, the inner surface of the cap <NUM> has a shoulder portion <NUM> located below the sealing member <NUM>.

As shown in <FIG>, <FIG>, and <FIG>, the bushing <NUM> is disposed between the outer tube <NUM> and the inner tube <NUM>, and includes an upper sleeve <NUM> and a lower sleeve <NUM>. In this embodiment, the upper and lower sleeves <NUM>, <NUM> are assembled together in a detachable manner. The upper sleeve <NUM> is rotatably disposed at the top end of the outer tube <NUM>, as shown in <FIG> and <FIG>. The upper sleeve <NUM> is made of metal so as to have a higher hardness. The upper sleeve <NUM> includes an annular main body <NUM> and an upper baffle ring <NUM>. The annular main body <NUM> is disposed above the upper baffle ring <NUM> and connected integrally with the upper baffle ring <NUM>. The upper baffle ring <NUM> is located at the bottom end of the upper sleeve <NUM>, and the bottom end of the upper baffle ring <NUM> has three first engaging portions <NUM> (actually, at least one is sufficient) arranged equiangularly. Each of the first engaging portions <NUM> is a concave hole. As shown in <FIG>, the first engaging portion <NUM> has a small diameter section <NUM> and a large diameter section <NUM> located above the small diameter section <NUM> and integrally connected with the small diameter section <NUM>. The large diameter section <NUM> is slightly round, and the small diameter section <NUM> extends from the bottom edge of the large diameter section <NUM> and decreases inwards.

As shown in <FIG>, <FIG>, and <FIG>, the lower sleeve <NUM> is received in the outer tube <NUM> and made of flexible material (such as plastic), such that the lower sleeve <NUM> can be slightly elastically deformed by an external force, and therefore the hardness of the upper sleeve <NUM> is greater than the hardness of the lower sleeve <NUM>. The lower sleeve <NUM> includes a lower baffle ring <NUM> located at the top end of the lower sleeve <NUM>, and a limiting portion <NUM> located at the bottom end of the lower sleeve <NUM>. The top end of the lower baffle ring <NUM> has three second engaging portions <NUM> (actually, at least one is sufficient) arranged equiangularly. Each of the second engaging portions <NUM> is a bump. The position of the second engaging portion <NUM> corresponds to the position of the first engaging portion <NUM> in a one-to-one manner, and the configuration of the second engaging portion <NUM> and the configuration of the first engaging portion <NUM> are complementary. Since the second engaging portion <NUM> is made of flexible material, the second engaging portion <NUM> can be slightly elastically deformed to be engaged with the first engaging portion <NUM>, so that the upper sleeve <NUM> and the lower sleeve <NUM> can be moved synchronously. In addition, the top edge of the lower baffle ring <NUM> of the lower sleeve <NUM> is almost completely abutted against the bottom edge of the upper baffle ring <NUM> of the upper sleeve <NUM>. Further, the bottom end of the lower sleeve <NUM> has three limiting portions <NUM> (actually, at least one is sufficient) arranged in an equally-spaced manner around the axis of the outer tube <NUM> and located above the protrusions <NUM> of the inner tube <NUM>. Each of the limiting portions <NUM> is formed by five limiting slots <NUM> arranged in a stepped manner along the axial direction of the outer tube <NUM>. One of the limiting slots <NUM> of the lower sleeve <NUM> is abutted against one of the protrusions <NUM> of the inner tube <NUM> (see <FIG> and <FIG>), i.e., the bushing <NUM> is abutted against the protrusions <NUM> of the inner tube <NUM> through the limiting portions <NUM> of the lower sleeve <NUM>. In addition, the outer surface of the upper baffle ring <NUM> of the upper sleeve <NUM> is flushed with the outer surface of the lower baffle ring <NUM> of the lower sleeve <NUM>, and the inner surface of the upper baffle ring <NUM> of the upper sleeve <NUM> is flushed with the inner surface of the lower baffle ring <NUM> of the lower sleeve <NUM>.

It can be seen from the above that since the outer surface of the upper baffle ring <NUM> of the upper sleeve <NUM> is flushed with the outer surface of the lower baffle ring <NUM> of the lower sleeve <NUM>, i.e., the outer surface of the upper baffle ring <NUM> does not protrude radially out of the outer surface of the lower baffle ring <NUM>, the structural volume of the liftable seatpost <NUM> at the position corresponding to the bushing <NUM> can be designed smaller without protruding too much from the outer surface of the outer tube <NUM>, such that the overall appearance is more concise and has a better appearance. On the other hand, since the top edge of the lower baffle ring <NUM> of the lower sleeve <NUM> is abutted against the bottom edge of the upper baffle ring <NUM> of the upper sleeve <NUM>, when the inner tube <NUM> is driven by the pneumatic cylinder <NUM> to a desired or a predetermined height, and the protrusion <NUM> of the inner tube <NUM> is abutted against one of the limiting slots <NUM> of the limiting portion <NUM> of the lower sleeve <NUM>, the stress generated from the protrusion <NUM> can be effectively distributed through the full abutment between the top edge of the lower baffle ring <NUM> and the bottom edge of the upper baffle ring <NUM>, such that wear between the upper and lower sleeved <NUM>, <NUM> can be reduced to increase the service life of the liftable seatpost <NUM>.

As shown in <FIG>, <FIG>, and <FIG>, in order to increase lubricating effect, a liftable seatpost <NUM> further includes a backing ring <NUM>. The backing ring <NUM> is a self-lubricating bearing in the embodiment. The backing ring <NUM> is disposed in the annular main body <NUM> and located between the upper sleeve <NUM> and the inner tube <NUM> for reducing friction between the bushing <NUM> and the inner tube <NUM>.

Claim 1:
A liftable bicycle seatpost (<NUM>) comprising:
an outer tube (<NUM>);
an inner tube (<NUM>) movably disposed upwards and downwards in the outer tube (<NUM>), and having a top end thereof located outside the outer tube (<NUM>) and a bottom end thereof received in the outer tube (<NUM>), an outer surface of the inner tube (<NUM>) having a protrusion; and
a bushing (<NUM>) disposed between the inner tube (<NUM>) and the outer tube (<NUM>), and having an upper sleeve (<NUM>) rotatably disposed at a top end of the outer tube (<NUM>) and a lower sleeve (<NUM>) received in the outer tube (<NUM>) and disposed at a bottom end of the upper sleeve (<NUM>), a bottom end of the upper sleeve (<NUM>) having an upper baffle ring (<NUM>) provided with a first engaging portion at a bottom end thereof, a top end of the lower sleeve (<NUM>) having a lower baffle ring (<NUM>) provided with a second engaging portion at a top end thereof engaged with the first engaging portion of the upper baffle ring (<NUM>), so that the upper sleeve (<NUM>) and the lower sleeve (<NUM>) are moved synchronously, characterized by
a top edge of the lower baffle ring (<NUM>) of the lower sleeve (<NUM>) being abutted against a bottom edge of the upper baffle ring (<NUM>) of the upper sleeve (<NUM>), a bottom end of the lower sleeve (<NUM>) having a limiting portion (<NUM>) abutted against the protrusion of the inner tube (<NUM>);
wherein an outer surface of the upper baffle ring (<NUM>) of the upper sleeve (<NUM>) is flushed with an outer surface of the lower baffle ring (<NUM>) of the lower sleeve (<NUM>).