TW202300383A - Front fork for a bicycle - Google Patents

Abstract

A front fork for a bicycle, in particular for a BMX bike or a mountain bike, having a fork steerer with an upper and a lower section, two blades each having an upper and a lower section as well as means for receiving a wheel axle fitted to each of the lower sections of the blades in which at least the lower section of the fork steerer and the upper sections of the blades are provided as an integrally shaped component and in which the upper sections of the blades are integrally shaped longside with the lower section of the fork steerer.

Description

front fork for bicycle

The present invention relates to a front fork for a bicycle, which is especially suitable for a BMX bicycle or a mountain bike.

The front fork is a component of a bicycle used to connect the front wheel to the bicycle frame. The front fork generally comprises: a steering fork (fork steerer), which is formed as a straight tube passing through the bicycle frame; a fork crown, which is fitted to the lower end of the steering fork; and two blades, etc. Connected to the crown, and each has a member at its lower end to receive the axle of the front wheel of the bicycle.

Additionally, front forks for bicycles are known to have a double crown. A double crown system consists of two prong systems arranged parallel to each other and spaced apart from each other, through which two substantially parallel knives pass.

Especially when the bike rides up bumps, down steps or jumps, considerable impact occurs which is transmitted from the bike's front wheel to the front fork.

The front fork thereby has to withstand enormous forces, which can negatively affect the stability and lifespan of this bicycle component. In this way, the steering fork may be damaged when riding forward or backward. Furthermore, the fork crown may be damaged during high axial loads, or the connection between the steering fork and the fork crown may crack or break completely.

For this reason, some front forks for bicycles are known in the prior art, which have attempted to increase the structural capacity of the fork so that it can withstand these higher loads and is less susceptible to damage.

Thus, a front fork for bicycles is known from German patent DE 20 2008 001 739 U1, wherein the blades are connected to the fork crown and provided with a rib, which is located on the upper section of one of the blades inside.

This rib does increase the rigidity of the knives in their upper section. However, this construction is still prone to damage in the connection area between the steering fork, crown and knife.

Furthermore, a frame system for bicycle front forks is disclosed in DE 20 2008 001 871 U1, wherein not only the head tube is provided with an axial rib, but also the blades are each provided with an axial rib.

In this embodiment too, only the individual components making up the front fork are reinforced by ribs. However, this construction also includes a steering fork, a fork crown and two knives, which are connected to one another, and where damage can occur during high loads in the region where these components are connected to one another.

Furthermore, a bicycle fork and a bicycle frame with a bicycle fork are known from German patent publication DE 20 2013 104 420 U1, wherein the steering fork comprises at least one flat part. This flat portion will considerably increase the lateral stiffness of the steering fork, so as to enhance its elasticity and life.

Finally, it is known from the publication of the German invention patent DE 20 2006 011 859 U1 that the front fork system for bicycles comprises a steering fork made of fiber-reinforced material and two blades, wherein the blades each have Two inner tubes butted with each other and an outer tube installed on the two inner tubes, wherein the butt joint portion of the two inner tubes forms a rib. In this configuration, the structural capacity is increased by clamping several tubes to each other and strengthening the connection area between the tubes by twisting of the prepreg.

One disadvantage of this construction is that the structural capacity is substantially dependent on the number of prepregs used, and an increased number of twists in one of the prepregs not only increases the structural capacity but also increases the weight of the fork.

It is therefore an object of the present invention to provide a front fork for a bicycle, in particular for a BMX bicycle or a mountain bike, in which the structural capacity in the area where the steering fork is connected to the blade is considerably increased, and preferably The ground has a weight as low as possible.

According to the invention, the object is achieved by the characteristics of claim 1.

The front fork system of the present invention includes a steering fork, which has an upper section and a lower section. The steering fork essentially consists of a straight tube and can be formed in one piece or consist of several parts.

In addition, the front fork system of the present invention has two blades, each with an upper and a lower section. The knives may also be formed in one piece or consist of several parts. At the bottom of each lower section of the knives there is provided means for receiving an axle. These members are fork ends into which the axle can be inserted and thereafter secured by fasteners.

According to the invention, at least the lower section of the steering fork and the upper section of the knife-shaped portion are integrally formed as one component. Thus, the section below the steering fork and the section above the knife are not, unlike those known in the prior art, separate parts arranged to be welded or welded to each other. For example, such components can be manufactured by a hydroforming process, in which composite shapes can be produced from a tube body by pressing a hot oil-water mixture into a hollow mold. By providing one integrally formed component, the disadvantages of known front forks are avoided, since there are no assembly seams between components in this highly stressed area which could break under high loads.

The upper section of the knives is here longitudinally integrally formed with the lower section of the steering fork.

In a preferred embodiment of the front fork of the present invention, the lower section of the steering fork is configured as a tube, which completely penetrates the assembly. In this embodiment, the region where the knife-like portions are integrally formed longitudinally with the steering fork covers the steering fork. In this way, a particularly large contact surface is created in the region where the knives are integrally formed with the steering fork. With the increased contact surface between the steering fork and the knives, the assembly gains an additional degree of stability and rigidity.

In another embodiment of the front fork of the present invention, the diameter of the section above the blades decreases towards the section below the blades. In this embodiment, the most stressed part of the component is strengthened with a larger aperture, while the aperture in the less stressed area of the blade is tapered to facilitate building a fine shape and to facilitate Material and weight can be reduced.

In a further developed embodiment of the front fork according to the invention, the bores of the knives, at least in the region where they are integrally formed with the steering fork, have a substantially oval shape. The contact surface between the knives and the diverting fork is significantly increased by an oval aperture compared to a circular aperture.

As an alternative to this, the diameter of the knives where they are integrally formed with the steering fork may be substantially drop-shaped, wherein the diameter of the blades tapers towards the hub. In this embodiment also results in an enlarged contact surface between the knives and the steering fork, while reducing material and weight.

A particularly preferred embodiment of the front fork of the invention provides a bore where the knives are integrally formed with the steering fork, substantially circular in its upper section, below the bore The segments have a tapered structure and form a base in a generally planar face in the lowermost segment thereof. In practical tests, this embodiment has proven optimal and achieves a high degree of stability and rigidity.

In addition, an embodiment of the front fork of the present invention is disclosed, wherein the upper section of the blades forms a rib running in the longitudinal direction from the area where the blades and the steering fork are integrally formed. The rib extends toward the lower section of the knife-shaped parts on the lateral surface of the knife-shaped parts. In a two-piece embodiment of the blades in which the upper and lower segments of the blades are connected to each other, the rib terminates in the contact area between the segments. In this embodiment, the lower part of the blade has a tapered shape in the direction for receiving the member of the hub. Alternatively, the section below the knife-shaped portions can also be formed as a uniformly shaped tube.

In another embodiment of the invention of the claimed front fork, it is foreseen that the front fork, at least in the area of the central assembly comprising the section below the steering fork and the section above the knives , is made of chromium- and molybdenum-alloy steel. Chromium-molybdenum steel is distinguished by its hardness, wear resistance and impact strength. Furthermore, this steel has a high solids/weight ratio and a high torsional strength, and is therefore a most suitable material for heavy-duty front forks of BMX bicycles and/or mountain bikes.

Figure 1 shows a front view of the front fork of the present invention. Figure 1 shows a steering fork (1) with an upper and a lower section (1', 1''), which is formed as a tubular body (4). The lower section (1'') of the steering fork passes through the upper section (2') of the knife-shaped part (2). The knife-like portions (2', 2'') are integrally formed longitudinally with the lower section (1'') of the steering fork. Thereby, the area (5, 5') where the knife-like parts are integrally formed with the steering fork covers the tube body (4) of the steering fork (1).

The diameter (6) of the section above the blade (2) decreases towards the section (2'') below the blade. In this way, a large contact area is created in the area (5, 5') where the knives are integrally formed with the steering fork, which provides a particularly high stability in this area. For this reason, Figure 1 also shows ribs (10) which originate from the area (5, 5') where the knives are integrally formed with the steering fork and which gradually progress towards the section below the knives. shrink. On each lower section of the knives there is provided means for receiving an axle.

Figure 2 shows a side view of a front fork according to the invention, wherein the means for receiving the axle are clearly visible.

Figure 3 shows an assembly with the lower section (1") of the steering fork and the upper section (2') of the knives integrally formed with it. The diameter (6) of the knives is derived from the knives The area integrally formed with the steering fork decreases towards the section (2'') below the knives. In this area, the ribs (10) located on each side are also shown in FIG. 3 as visible.

Figure 4 shows a section (7, 7', 7'', 7''') of one of the knives in the region where the knives are integrally formed with the steering fork. The cross-section (7, 7', 7'', 7''') of the knife-like portion is generally circular in the upper part, while the lower part of the cross-section tapers and is in a generally planar plane form a base. In this section, a rib (10) is formed in the transition region between the upper circular portion and the tapered portion. The cross-section shows a generally oval shape resembling an upside-down drop shape (9).

1: steering fork 1': upper section 1'': the lower section 2: knife-shaped part 2': blade, upper section 2'': knife-like part, lower section 3: Component 4: tube body 5,5': The area where the knife-like part and the steering fork are integrally formed 6: Caliber 7: Section 7': section, upper part 7'': section, lower part 7''': section, generally planar surface 8: Oval shape 9: drop shape 10: Rib

Figure 1 shows a front view of the front fork of the present invention.

Figure 2 shows a side view of a front fork according to the invention, wherein the means for receiving the axle are clearly visible.

Figure 3 shows an assembly with the lower section (1") of the steering fork and the upper section (2') of the knives integrally formed therewith.

Figure 4 shows a section (7, 7', 7'', 7''') of one of the knives in the region where the knives are integrally formed with the steering fork.

1: steering fork

1': upper section

1": lower section

2: knife-shaped part

2': blade, upper section

2": Knife, lower section

3: Component

4: tube body

5,5': The area where the knife-like part and the steering fork are integrally formed

10: Rib

Claims (8)

A front fork for a bicycle, in particular for a BMX bicycle or a mountain bike, the front fork has a steering fork (1) with an upper section (1') and a lower section (1"); two a knife-like portion (2), each having an upper section (2') and a lower section (2 "); and a member (3) for receiving an axle, which is fitted to the knife-like sections (2 ), each of the subsections (2") below Its characteristics are: At least the lower section (1'') of the steering fork (1) and the upper sections (2') of the knives (2) are provided as an integrally formed component, and the knives The upper sections (2') of the part (2) are integrally formed longitudinally with the lower section (1") of the steering fork (1). Such as claim item 1 for bicycle front forks, Its characteristics are: The lower section (1") of the steering fork (1) is formed into a tubular body (4), and the knife-like parts of the knife-like parts (2) are integrally formed with the steering fork ( 5, 5') are covering the pipe body (4). If either item 1 or 2 is preceded by a fork, Its characteristics are: The diameter (6) of the upper section (2') of the knives (2) decreases towards the lower section (2'') of the knives (2). If any one of claims 1 to 3 is used for bicycle front forks, Its characteristics are: The section (7) of the knives (2) integrally formed with the steering fork (1) is a substantially oval shape (8). If any one of claims 1 to 3 is used for bicycle front forks, Its characteristics are: The section (7) of the knife-like parts (2) integrally formed with the steering fork (1) is substantially Drop-shaped (9). If any one of claims 1 to 5 is used for bicycle front forks, Its characteristics are: The cross-section (7) of the knives (2) integrally formed with the steering fork (1) has a substantially circular shape in its upper part (7'), the lower part (7) of the cross-section (7) '') are tapered and form a base in a generally planar face (7'''). If any one of claims 1 to 6 is used for bicycle front forks, Its characteristics are: The upper section (2') of the knives (2) is provided with a rib (10) from the area where the knives are integrally formed with the steering fork (1) towards the knives (2) The lower section (2'') walks. If any one of claims 1 to 7 is used for bicycle front forks, Its characteristics are: The front fork is at least partially made of chromium and molybdenum alloy steel.

Images