JPH0224712Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sealing device at the front fork and head joint of a bicycle. As is well known, the ends of the handlebar post and front Hawk stem of a bicycle are inserted into the head pipe, and the handle post and the front Hawk stem are each provided with a cone part, and the head pipe is each provided with a one part. A structure was adopted in which a plurality of balls were interposed between the two parts to rotatably support the handle post and the front Hawk stem.

However, in the joints of the above structure, water easily enters the head pipe from the outside.
In particular, at the joint of the front fork stem, rainwater that collects on the shoulder of the front fork tends to rise up the stem due to capillary action and enter the head pipe through the joint, and the internal grease flows down from this joint. It also had the disadvantage of being easily leaked outside. For this reason, conventionally, as shown in FIG. 1, an annular groove c was formed in each of the lower one a and the lower ball pusher b, and an O-ring d was fitted into the annular groove to form a sealing device.

However, with the above sealing device, the lower one a
A groove c into which the O-ring d is fitted must be formed in the lower ball pusher b, and the operation of fitting the O-ring d into the groove c is also extremely difficult.

In view of the above circumstances, the purpose of this invention is to provide a sealing device for the joint between the front fork and head of a bicycle, which has an extremely simple structure and can reliably prevent water intrusion and the outflow of grease, etc. The feature is that it has a body that fits on the lower periphery of the lower one at the joint between the front fork and the head of the bicycle, and a bottom plate that supports the lower end surface of the lower one, and the inner circumference of the bottom plate has a required angle. An annular dust cover having an inwardly erected inclined piece is fitted onto the lower peripheral edge of the lower one. The invention will be explained below based on the illustrated embodiment. FIG. 2 shows the joint between the front fork and handle post of a bicycle and the head pipe. Reference numeral 1 denotes a front fork of a wheel of a bicycle, and a front fork stem 2 is installed at the center of the upper end of a shoulder portion 1a of the front fork 1. An annular lower ball pusher 4 is inserted downward and has a curved ball receiving portion 4a on its outer periphery at the base end of the reduced diameter portion 2a. Further, a fitting part 5b provided above the lower one 5 having a curved ball receiving part 5a on the inner periphery is fitted into the lower end opening of the head pipe 3, and a ball formed on the inner periphery of the lower one 5 is fitted. A plurality of balls 6 are interposed between the receiving part 5a and the ball receiving part 4a formed on the outer periphery of the lower ball pusher 4 to form a joint between the front Hawk stem 2 and the head pipe 3. On the other hand, 7 is a bicycle handlebar, and a handlebar post 8 is located at the center of the lower end of the handlebar 7.
is vertically installed, and the tip of the handle post 8 is inserted above the head pipe 3, and an annular upper ball pusher 9 having a ball receiving portion 9a on the outer periphery is provided at the base end of the inserted portion. A fitting part 10b provided below the upper one 10 having a ball receiving part 10a on its inner periphery is fitted into the upper end opening of the head pipe 3, and the ball receiving part 10a of the upper one 10 and the ball of the upper ball pusher 9 are fitted. A plurality of balls 6 are interposed between the receiving portions 9a to form a joint between the handle post 8 and the upper end of the head pipe 3. At the joint between the handle post 8 and the upper end of the head pipe 3, an O-ring 12 is fitted into an annular groove 11 formed on the inner peripheral surface of the upper part of the upper one 10, and an A sealing device is constructed by extending an annular eaves portion 13 that covers the upper outer periphery of the one 10.

In the sealing device as described above, water flowing down through the handle post 8 is blocked by the eaves section 13 and does not enter the joint at the upper end of the head pipe 3, and water that reaches the inside of the eaves section is also blocked by the O-ring. 12 and will not enter the joint. On the other hand, in this invention, the joint between the front hawk stem 2 and the head pipe 3 is made of a flexible material such as nylon, and its shape is a body part 14a of a required height to fit on the lower circumference of the lower one 5.
It has a bottom plate part 14b that supports the lower end surface 5c of the lower one, and has an annular inclined piece 14c with a tapered tip that stands up inward at a predetermined angle on the inner periphery of the bottom plate part 14b. The dust cover 14 is attached to the tip of the inclined piece 14c on the lower outer peripheral surface 4b of the lower cone pusher 4.
A sealing device is formed by contacting with and fitting onto the lower peripheral edge 5d of the lower one 5.

The sealing device configured as described above is extremely simple compared to the conventional sealing device using an O-ring.
It is also manufactured at low cost. Moreover, dust cover 14
When it is fitted into the lower one 5, the lower outer peripheral surface 4b of the lower cone 4 and the inclined piece 14 of the dust cover 14
Since the tapered tip of c contacts properly and the joint between the front Hawk stem 2 and the head pipe 3 is completely sealed, water that has risen up the front Hawk stem 2 due to capillary action etc. is also blocked by the dust cover 14. Grease and the like introduced into the joint to enhance the lubrication effect will not leak out. Furthermore, dust cover 1
4 is made of a flexible material, and the tip of the inclined piece 14c is tapered, so that the tip of the inclined piece 14c contacts the lower outer circumferential surface 4b of the lower cone pusher 4 in a flexible manner. It is possible to seal without generating friction at the contact portion of the lever.

In summary, according to the present invention, it is possible to manufacture at a very low cost a sealing device that is comparable in function to conventional sealing devices such as O-rings at the joint between the front fork and the head pipe of a bicycle.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the main parts of a conventional sealing device for the joint between the front fork and the head pipe, Fig. 2 is a longitudinal sectional front view showing the joint between the front hawk, the handle post and the head pipe, and Fig. 3 is a front view of the main part of the conventional sealing device for the joint between the front fork and the head pipe. FIG. 4 is an enlarged vertical sectional front view of the main part of the sealing device at the joint between the front fork and the head pipe, FIG. 4 is an oblique view of the dust cover, and FIG. 5 is an enlarged sectional view taken along the line A-A' in FIG. 4. 1...Front Hawk, 2...Front Hawk Stem, 3...
...Head pipe, 4...Lower ball pusher, 5...Lower one,
14...Dust cover.

Claims (1)

[Scope of utility model registration request] At the joint between the front fork and head of a bicycle, where a plurality of balls are interposed between the lower ball pusher provided on the front hawk stem and the lower ball provided on the head, the lower part of the lower ball is made of a flexible material. It has a body part of a predetermined height that fits around the periphery, and a bottom plate part that supports the lower end surface of the lower one, and stands up inward at a predetermined angle on the inner periphery of the bottom plate part, and has a tapered tip. 1. A sealing device characterized in that an annular dust cover having an inclined piece is fitted onto the lower peripheral edge of the lower cone with the tip of the inclined piece in contact with the outer peripheral surface of the lower part of the lower cone.