GB2327727A - Hydraulic brake operation in bicycles - Google Patents

Abstract

A device in a hydraulic line extending from a brake lever operated means on the handlebars of a BMX bicycle to a brake mounted on the bicycle frame, comprises a first disc 8 fixed on the steering tube 5 of the frame and a second disc 9 rotatable with the handlebars. Hydraulic pipes 6, 7 are connected via pipe connections 16, 34 and an annular passage 11 defined by the discs, and the device enables a complete rotation, in either direction, of the handlebars about the axis of the steering tube.

Description

A DEVICE FOR THE CONNECTION OF A HYDRAULIC LINE BETWEEN A STEERING UNIT AND A FRAME ON BMX-BICYCLES The invention relates to a device for the connection of a hydraulic line between a steering unit and a frame on BMX-bicycles. These special bicycles must be designed so that the front wheel can be turned in both directions, whichever is required, using the handlebar, and in particular complete rotations of the front wheel can be carried out in either direction. The problem arises here of transmitting the power and/or the oil pressure from the brake lever on the handlebar to the brake bodies.

In the case of cable brakes, the transmission occurs via at the most four cables and one ball bearing, whereby high losses result in the cables. Furthermore, these known devices cannot be used for hydraulic brakes because transmission of the brake fluid from the rotating to the fixed part is not possible.

The object underlying the invention is to provide a device of this kind which enables hydraulic brakes to be used on special BMX wheels such as these. In addition, the design should be improved also with regard to the arrangement of the seals.

This object is solved according to the invention in that between the steering unit and the frame, a first disc, which is mounted on the steering tube and a second disc, which is connected to the steering unit and disposed on it so that it can rotate, are provided, and in that the discs are provided with annular grooves and connection bores for the attachment and connection of the hydraulic line.

Advantageous developments of the invention arise from the subsidiary claims.

The invention is described in greater detail in the following description, on the basis of embodiment examples shown in the drawings.

Fig 1 shows a view of the device incorporated on the bicycle, Fig 2 shows a first embodiment of the device in partial section, Fig 3 shows a plan view onto a device of this kind according to a first embodiment form, Fig 4 shows a longitudinal section according to Fig. 3, Fig 5 shows a further embodiment of the device in plan view, Fig 6 shows a longitudinal section according to Fig. 5, Fig 7 shows a plan view onto a further embodiment of the device and Fig 8 shows a partial section according to Fig. 7.

In Fig 1 the front part of the bicycle is shown, whereby the steering unit is disposed on the frame 1. This steering unit consists essentially of the handlebar 2 which is mounted on a front part 3, and the fork 4, whereby this steering unit is rotatably mounted on the frame 1.

Mounting occurs on a steering tube 5 of the frame 1 and there is a ball bearing socket 20 at the transition of the fork 4 to the steering tube 5. A fork shaft 21 is fastened on the fork 4, said shaft being mounted in the steering tube 5.

When a hydraulic brake is installed, transmission must take place from the rotating part, i.e.

the steering unit, to the fixed part, i.e. the frame. On the steering tube 5 of the frame 1 a first fixed cylindrical shell 8 is mounted, into which a cylindrical nut 9 is inserted which is connected to the steering unit. The two parts 8, 9 are provided with unions 16 and 34 respectively, on to which a hydraulic line 6 to the brake lever and a hydraulic line 7 to the brake are attached. The hydraulic line 6 is guided out laterally on the nut 9 via an angular connector 34 as union and the union 16 is guided diagonally downwards so that the danger of damage to the lines 6, 7 is considerably reduced. There are connection grooves and bores in the two discs 8, 9 so that the brake fluid can pass from line 6 to line 7 and vice versa. The part 9 is secured on to the fork shaft 21 with the help of a steering set nut 10.

In Fig 2 a first embodiment form for the design of the device is shown, whereby there is a ball bearing 18 between the two discs 8, 9 and in the outer area between the two discs 8, 9 there is an annular groove 11 running round, with connecting bores 14 and connector sockets 16 for the hydraulic lines 6 and 7 respectively. The annular groove 11 is sealed with the help of seals 25. In addition, the steering set nut 10 is provided with an extended shaft 26 on which the disc 9 and/or the ball bearing 18 are fitted.

With this embodiment the hydraulic power of the brake system acts between the contiguous surfaces of the discs 8, 9 and the connections can occur in an axial direction so that the outside diameter is somewhat reduced and, moreover, components which may be a hindrance, which protrude laterally, can be dispensed with.

According to the other embodiment of the device shown in Figs 3 and 4, the fixed, cylindrical disc 8 has a cup-shaped receiving part 35, on to which, towards the bottom, an annular flange 19 is connected, whereby the part 8 is pressed with this flange on the frame, i.e. into the steering tube 5. The fixed disc 8 has an outer ring 17 into which the second disc 9 is received. On the outer periphery 15 ofthe disc 9 there is a circulating annular groove 12 into which the connection bores 14 of both discs 8, 9 open out. The movable, cylindrical nut 9 is inserted into this cup-shaped receiving part 35 and is arranged over the shell 8 with a projection 36. Between the two parts 8, 9 there is a ball bearing 18 which is also responsible for the mounting ofthe fork. The unions 16 for the hydraulic lines 6, 7 are led out sideways on the parts 8, 9 whereby in the cylindrical part 37 of the nut 9 there is an annular groove 11 around the full circumference, which is sealed on both sides with the help of sealing rings 29 which are disposed in corresponding recessed grooves. The connection to the union 16 in the nut 9 is via an axial connecting bore or milled recess 14 and a further connecting bore 27 in the shell 8. The connection bore 14 is sealed towards the outside by a blind plug 33. In addition, the nut 9 is provided towards the bottom with an extended shaft 26 and thus fitted into the ball bearing 18.

The device is screwed on to the fork shaft 21, with the movable cylindrical nut 9 which has an internal thread. The nut 9 is fixed relative to the fork shaft 21 through clamping bores 28 in the nut 9, which are directed diagonally to the fork shaft 21.

This is provided on the system of the threaded steering sets. On the system of the plain steering sets, these bores are omitted. The nut is a bush placed on the fork shaft.

In the further embodiment shown in Fig 5 and 6, an annular hollow space 38 is formed by means of suitable steps 31 and 32 respectively, in the region of the cylindrical part 37 between the shell 8 and the nut 9, in which, on both sides of the hollow space 38, the sealing rings 29 can be inserted.

The invention essentially provides the advantage that for the arrangement of the seals deep recesses are no longer needed, which has a beneficial effect particularly for the production engineering; the sealing problem is also reduced. Through the hollow space and the seals being disposed above the ball bearing, there is the further advantage of a more compact construction.

In the embodiment of the device shown in Fig 7 and 8, instead of the nut 9 a suitably designed bush 9' is provided which is placed on the fork shaft 21. Fixing is done in the same way as for conventional thread-less steering sets, with the help of the front part. The clamping cone 39 serves the balance out the radial play ofthe device. Clamping bores 28 are not necessary on this embodiment form.

Claims (11)

1. Device for the connection of a hydraulic line between a steering unit and a frame on BMX-bicycles, consisting of a first disc mounted on the steering tube and a second disc rotatably mounted thereon and connected to the steering unit, and in that the discs are provided with annular grooves and connecting bores for the attachment and connection of the hydraulic line.

2. Device as claimed in Claim 1, characterised in that the second disc is disposed with its outer edge inside an inner circumference of an outer ring of the first disc, whereby the annular groove is formed in the outer edge of the second disc.

3. Device as claimed in Claims 1 and 2, characterised in that on both sides of the annular recess in the outer circumference of the movable, cylindrical shell, sealing rings are inserted in annular grooves.

4. Device as claimed in Claims 1 to 3, characterised in that a ball bearing is disposed between the discs, in that the annular groove is provided in the outer annular area between the discs, and the connection bores are connected to the annular groove.

5. Device as claimed in one of the Claims 1 to 4, characterised in that in the annular area of the parts steps (31, 32) form a cylindrical hollow space to receive the sealing rings.

6. Device as claimed in Claims 1 to 5, characterised in that the unions for the hydraulic lines are disposed laterally on the parts.

7. Device as claimed in Claims 1 to 6, characterised in that the annular hollow space is disposed above the bearing.

8. Device as claimed in Claims 1 to 7, characterised in that the first disc, provided with an annular flange, is pressed into the steering tube of the frame.

9. Device as claimed in Claim 1 to 8, characterised in that the second disc is mounted with the help of a steering set nut on the rotating fork shaft of the fork.

10. Device as claimed in Claims 1 to 9, characterised in that clamping bores which are directed diagonally to the fork shaft are provided in the nut.

11. Device as claimed in one of the Claims 1 to 10, characterised in that a bush placed on the fork shaft is provided as nut.