JPS633589Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application This invention relates to a center bolt structure used in bicycle side-pull brakes, and in particular to an improvement in a retaining portion that supports a spring that is stretched between brake arms.

In the case of a side-pull type brake, a spring that is hooked between the brake arms to repeatedly drive the brake arms in the brake release direction is supported by a spring retainer that is integrally formed with a center bolt that attaches the brake arms.

As shown in FIG. 1, this spring holding part A is conventionally produced by die-casting into a cylindrical shape on a collar provided on a center bolt 1.

In this case, the manufacturing process is only one step, but the center bolt inserted during die casting may shift or move, which tends to result in defective products. There are also inherent drawbacks to die casting, such as the occurrence of casting cavities.

Furthermore, if you tighten the tightening nut on the bicycle hawk, excessive thrust will cause the flange B of the center bolt to tighten.
The die-cast holding part A is plastically deformed, and the center bolt itself is pulled in the direction of the fork. As a result, additional tightening force is applied to the brake arm, which has been set with appropriate tightening, resulting in the disadvantage that the brake cannot be operated smoothly and readjustment is required.

In addition, as shown in the second figure, there is also a configuration in which a spring retainer A' made of a metal annular body is caulked and fixed to the middle part of the center bolt 1, but in this case as well, the center bolt is tightened to the hawk. There is a risk that the caulking part may loosen and come off due to the thrust action that occurs.

Furthermore, in the mounting bolt and spring retainer for attaching a bicycle side-pull type brake disclosed in Utility Model Publication No. 50-8843, a structure in which a large diameter flange is sandwiched between a spring retainer and a polygonal retainer is known.

In the above configuration, the polygonal fixing metal is fitted into the polygonal cross-sectional opening formed in the spring retainer through the collar, so the polygonal fixing metal always collides with the spring retainer at the polygonal circumferential surface. There is.

Therefore, the loads applied to the spring retainer and the polygonal fixture are transferred to each other, and the stress cannot still be dispersed.

Problems that the invention aims to solve This invention was devised as a result of intensive research in view of the above circumstances, and its purpose is to easily and reliably fix the bolt to the center bolt, and to reduce the thrust and brake braking that occurs when tightening the fork. To provide a center bolt structure of a highly reliable side-pull type brake that can withstand repeated loads applied at times.

Means for solving the problem In order to achieve the above object, this invention has a flange protruding from the middle part of the center bolt used in side-pull type brakes, and a spring that is divided into front and rear parts with the flange in between. In the center bolt structure of a side-pull brake with a retainer attached, (a) a raised part that is integrally provided on the center bolt in contact with the front of the flange and has a smaller diameter than the flange that forms a corner on the outer periphery; (b) A tapered portion is provided that gradually increases in diameter from the circumferential surface of the center bolt toward the raised portion. (c) The spring retainer has a center bolt insertion hole in the center and a spring support groove in the left and right direction. (d) The spring support with the spring support groove is inserted from the front of the center bolt, and the cradle is inserted from the rear. The spring support is press-fitted onto the center bolt with the spring support groove facing forward at the position where the flange abuts, and the spring support and pedestal are attached through the flange in a non-contact manner. Technical measures are being taken.

Embodiments Hereinafter, preferred embodiments of this invention will be described based on the drawings.

The center bolt structure shown in FIG. 3 consists of a center bolt 1 having a flange 2, a spring support 5 inserted from the front, and a cradle 7 inserted from the rear. 7 are fixed to the center bolt 1 with the flange 2 in between.

That is, the center bolt 1 has a threaded groove portion 1 on the front and rear ends.
1 and 12, and is integrally formed with a disk-shaped flange 2 that protrudes in the circumferential direction slightly toward the front of the midway portion.

A fixing means 3 is formed on the axis of the center bolt at the front end of the collar 2.

In the case of this embodiment, the fixing means 3 consists of a raised part 31 connected to the collar part 2 and formed in the shape of a polygonal column, and a tapered part 32 connected to the raised part 31.

Since this is used to press-fit and fix the spring support 5 from the front, which will be described later, it is not limited to the above configuration, but may be, for example, one or more protrusions protruding in the axial direction or circumferential direction. It may or may not be connected to the brake 2.

Further, it is preferable that the cross-sectional shape has a feather-like shape and a tapered surface serving as a guide on the pressure-fitting side, but the shape is not limited thereto.

In short, the fixing means 3 of the present invention includes all shapes and configurations as long as the metal spring support 5 can be press-fitted and fixed at the abutting position of the collar 2.

Next, a fixing means 4 for a pedestal is formed on the axis of the center bolt at the rear end of the flange 2.

This fixing means 4 is not an essential component of this invention, and the fixing method may or may not be the same as that of the fixing means 3 for the spring support 5, and for example, a screw structure may be used.

In the illustrated example, the fixing means 4 have the same construction as the fixing means 3 for the spring support 5.

Next, the metal spring support 5 fitted into the center bolt 1 may be an annular body having a spring support groove 6 of a known structure, but in this embodiment, it is formed on the front outer periphery of a disk having an insertion hole 51 in the center. The illustrated example has a circumferential wall 52 protruding along the circumferential wall, and a pair of spring support grooves 6, 6 formed above and below the circumferential wall.

This spring support stand 5 is provided with a peripheral wall along the outer periphery on the front surface, and a pair of spring support grooves 6, 6 facing each other at positions parallel to and spaced from each other in the diametrical direction on the peripheral wall, and a brake spring is placed in the support grooves. When this happens, a gap is formed between the brake spring and the peripheral wall 52 adjacent to the brake spring, which is preferable because the load on the brake spring can be efficiently eliminated.

Therefore, as long as the above configuration is satisfied, the same effect can be achieved regardless of the planar shape or the number of spring support grooves (although it is two or more), which is preferable.

Further, in the case of this embodiment, the pedestal 7 is a metal disk having approximately the same outer circumference as the spring support 5, and has an insertion hole 71 in the center, and a wide flat raised part 72 is provided along the outer periphery of the back surface. A radial groove 73 is formed in the portion 72.

In this invention, the shape and configuration of the pedestal is not particularly limited, and may be any member that receives the thrust when tightening the fork, which will be described later.

Here, the insertion holes 51 and 71 provided in the spring support stand 5 and the pedestal 7 are set to a size approximately equal to the outer circumference of the center bolt 1, and the spring support stand 5 is set so that the spring support groove 6 faces the front. First, the pedestal 7 is press-fitted into the center bolt 1 from the front and rear directions with the raised portion 72 having the groove facing the back.

This press-fitting process may be performed by pressing from both the front and back directions until the flange 2 abuts, or by press-fitting from one direction, that is, by fixing one of the spring supports or pedestals with the center bolt inserted. Then, the non-fixed member may be press-fitted by applying pressure, and the fixed-side member may also be press-fitted via the collar portion 2 at the same time.

As a result, the spring support and the pedestal move to the clamping position where they abut the flange of the center bolt from the front and back.

At this time, the insertion holes of the spring support and the pedestal are guided by the tapered surface, plastically deformed to follow the polygonal columnar outer peripheral shape of the raised portion 31, and fixed to the center bolt.

The center bolt of the present invention, which fixes the spring support stand and cradle in this way, is similar to a normal center bolt with an integrally molded spring holding part, and together with other components constitutes a caliper brake, and is connected to the bicycle body through the fork. is fixed to.

An example of the assembly state of a side-pull type caliper brake using the center bolt structure of this invention is shown.

In the figure, 81 is a C arm, 82 is a Y arm, 3 is a boat rubber, 84 is a boat, 85 is a boat screw, 86 is a washer, 87 is a nut, 88 is a center bolt, 89
90 is a bag nut, 91 is a baked washer, 92 is a spring washer, 9
3 is a washer screw, 94 is a pipe screw, 95 is a lock nut, 96 is a daruma, 97 is a spring, 98
99 is the front spacer that comes into contact with the car body fork, and 99 is the rear spacer.

If the flange abutting portions are formed into recesses on the back of the spring support and the front of the pedestal, the width from the spring support to the pedestal can be set even thinner when the center bolt is attached.

In this way, in this invention, the spring support part and the pedestal are constructed separately, and each is fixed or attached to the center bolt, so when the brake is attached to the fork of the bicycle body via the center bolt, there is no possibility of excessive tightening caused by the tightening nut. The cradle absorbs most of the thrust in the axial direction of the center bolt that is generated when the brake is tightened, while the spring holder absorbs all of the repetitive load applied to the circumferential direction of the center bolt during braking. This results in improved durability.

Here, the width of the recess is set so that there is a slight gap between the support base and the cradle, so the cradle and the spring support base do not come into contact with each other and a slight gap is formed, allowing the center bolt to The structure is such that the thrust in the axial direction does not affect the spring support base.

It goes without saying that various other design changes may be made without changing the gist of this invention.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional example of a center bolt structure, Fig. 2 is a sectional view showing a different conventional example, Fig. 3 is a preferred embodiment of the center bolt structure according to this invention, and Fig. a shows each configuration. Perspective view showing the parts, b
Figure 4 is a cross-sectional view of the assembled state, Figure C is a perspective view seen from the rear side, and Figure 4 is a perspective view showing the installed state when a side-pull caliper brake is assembled using this center bolt structure. 1 is a center bolt, 2 is a flange, 3 is a fixing means, 5 is a spring support stand, 6 is a spring support groove, and 7 is a pedestal.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A side-pull type brake that has a flange protruding from the middle of a center bolt used in a side-pull type brake, and a spring retainer that is divided into front and rear parts across the flange. In the center bolt structure, a raised part is integrally provided on the center bolt that is in contact with the front of the collar and has a corner formed on the outer periphery and has a smaller diameter than the collar, and a raised part from the circumferential surface of the center bolt to the raised part. It has a tapered part that gradually increases in diameter in the opposite direction. The spring support base with the spring support groove is inserted from the front of the center bolt, and the spring support base is inserted from the rear, and the spring support base is placed at the flange abutting position, with the spring support groove facing forward. A center bolt structure of a side-pull type brake, which is press-fitted into the center bolt and is fixed to the center bolt, and the spring support stand and the pedestal are attached in a non-contact state via the flange. (2) The scope of the utility model registration claim, characterized in that the raised part and tapered part connected to the flange are also integrally formed with the center bolt at the rear of the flange, and the receiving part can be press-fitted and fixed. Center bolt structure of the side-pull brake described in item 1. (3) A practical use characterized in that the spring support base is formed by arranging a pair of spring support grooves in two stages parallel to the diametrical direction and slightly spaced apart from each other in a circumferential wall that protrudes forward along the outer periphery. A center bolt structure of a side-pull type brake according to claim 1 of the patent registration claim.