GB2031099A - Freewheel hub with back-pedalling brake - Google Patents

Abstract

A freewheel hub with a back- pedalling device for bicycles or the like comprises a driver (7), a hub shell (10), a grip-roller coupling (11) between the driver and the hub shell and a brake casing (16) inside the hub shell provided with a uniformly smooth inner bore. The brake casing can be expanded by means of a cone (15) axially displaceable via inclined gear surfaces (13) (14) (Fig. 3, not shown). The brake casing is prevented from independent rotation by means of radially inwardly directed dogs (21) acting against stop surfaces (22) of a bearing part (3) secured to the hub spindle (1). The spindle is uniformly smooth. Both the brake cone on the circumferential part thereof engaging the brake casing and the brake casing on its inside in the engagement zone of the brake cone have axially directed fluting (15a and 16a). <IMAGE>

Description

SPECIFICATION Freewheel hub with back-pedalling brake The invention relates to a freewheel hub with back-pedalling brake device for bicycles and the like, comprising a drive, a hub shell, a grip-roller coupling between the driver and the hub shell, a brake casing inside the hub shell provided with a uniformly smooth inner bore, which brake casing can be expanded by means of a cone axially displaceable via inclined gear surfaces and provided with a friction device against the brake casing, the brake casing being prevented from independent rotation by mean of radially inwardly directed dogs acting against stop surfaces of a bearing part (arm cone) secured on the hub spindle.

In a known freewheel hub with back-pedalling brake device there is provided as backpedalling brake a relatively thick-walled brake casing with an inerior profile for the backpedal lock and a cone engaging into the brake casing, which cone on an extension has as back-pedal lock a separate grip-roller coupling controllable by a control ring, the control ring itself being connected by means of friction springs to the surrounding brake casing which again is prevented from independent rotation via the arm cone. This design of a freewheel hub with back-pedalling brake device has satisfactory operational reliability but is expensive, in particular with regard to the number of components for the brake device.

In accordance with the invention there is provided a freewheel hub with a back-pedalling brake device for bicycles or the like, comprising a driver, a hub shell, a grip-roller coupling between the driver and the hub shell, a brake casing inside the hub shell provided with a uniformly smooth inner bore, which brake casing can be expanded by means of a cone axially displaceable via inclined gear surfaces and provided with a friction device against the brake casing, the brake casing being prevented from independent rotation by means of radially inwardly directed dogs acting against stop surfaces of a bearing part secured on the hub spindle, wherein the spindle carrying the hub components is made uniformly smooth, and wherein both the brake cone mounted directly on the hub spindle, on the circumferential part thereof engaging into the brake casing, and the brake casing on its inside in the engagement zone of the brake cone have an axially directed fluting. This design brings about, with respect to the com ponents required, an extremely simple freewheel hub with a back-pedalling device, wherein the actual components used do not necessitate any particular production outlay.

It is advantageous for a reliable operation of the freewheel hub if a compression spring is disposed axially between the brake cone and the brake casing inside the brake casing, which compression spring bears at one end against the retaining dog of the brake casing and, at the other end, against a collar part of the brake cone.

A simple design is achieved in that the friction device on the brake cone comprises a loop spring embracing the collar part and having radially projecting spring ends engaging in one of a plurality of slots of the divided brake casing.

A further simplified construction of a freewheel hub with a back-pedalling brake device may be achieved if the friction device on the brake cone is formed by the conical compression spring disposed inside the brake casing and bearing at one end against the retaining dog, the other coil end of said compression spring encircling the brake cone at a shoulder of the collar part by frictional resistance.

By way of example, two embodiments of a freewheel hub according to the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows in longitudinal section a hub according to the invention; Figure 2 shows on an enlarged scale a partial view of the essential parts of another embodiment of a hub according to the invention; and Figure 3 shows diagrammatically a view which applies to both embodiments.

In the drawings the numeral 1 denotes a hub spindle which is smooth in the zone inside the hub shell and which has screwed onto it at one end a fixed cone 2 and at the other end an arm cone 3. The arm cone 3 has a brake arm 4 (only partly shown) which is fastened to the frame (not shown) of the bicycle or the like by means of a separate clamp or clip, whereas for mounting the hub spindle in the frame clamping nuts (merely indicated) are used. A driver part 7 with a sprocket 8 is mounted on the fixed cone 2 via a rolling bearing 6. The driver 7 carries one end of a hub shell 10 via a ball-bearing 9, the other end being supported on the arm cone via a ball-bearing 5.

The driver 7 mounted directly on the hub spindle 1 projects axially with an extension part 7a relatively deeply into the hub shell 10 having a stepless interior bore and carries on this extension 7aa grip-roller locking mecha nism 11 which, upon forward rotation of the driver 7, is applied in drive direction from the interior against the hub shell 1 0. Moreover, a coaxial coupling member 1 2 is connected to the extension 7 a of the driver 7 so as to be incapable of independent rotation therewith and is retained axially by means of a locking ring 7b.This coupling member 12 has in clined surfaces 1 3 (see Fig. 3) which, during backward rotation of the driver 7, co-operate with corresponding inclined surfaces 14 on a brake cone 1 5 in such a way that the brake cone is moved axially away from the driver into a brake casing 1 6. This brake cone 15 is mounted axially displaceably on the hub spindle 1 and, during back-pedalling, is prevented from co-rotation with the coupling member 1 2 by means of a friction brake in the form of a loop spring 1 9 which is arranged on a collar part 15b of the brake cone 15; in this case the loop spring engages with a radially projecting end into one of a number of axial slots 1 8 of the brake casing 1 6 divided in longitudinal direction, said brake casing being encircled and prestressed radially inwards by a spring 1 7. The brake casing 1 6 in turn has radially inward directed dogs 21 which bear against contact surfaces 22 in the arm cone 3 and thereby ensure that the brake casing is incapable of independent rotation inside the hub shell.

Fig. 3 illustrates in a development the coupling member 1 2 and the brake cone 15. The forward-rotation direction of the coupling member 1 2 is indicated by arrows. When the coupling member 1 2 rotates forwards, it drives the brake cone 15 in the direction of the arrow via entrainment surfaces 31 of the coupling member 1 2 and entrainment surfaces 33 of the brake cone 15, in which case the loop spring 19 rubs on the collar part 15b of the brake cone 1 5. However, when the coupling member 1 2 is rotated backwards contrary to the direction of the arrow, the inclined surfaces 1 3 of the coupling member 1 2 are applied against the inclined surfaces 14 of the brake cone 15; but since the brake cone 1 5 is now prevented from co-rotation in backward direction by the loop spring 19, the brake cone 1 5 is shifted to the left in Fig. 3, i.e. into the brake casing.

The brake cone 15 is provided on its outer circumference, which in the event of axial displacement in an expanding direction is able to co-operate with the inner zone of the brake casing 16, with axially directed flutes 15a resembling teeth; furthermore, in the inner zone acted upon by the brake cone the brake casing has axial fluting 16a. The brake cone 15 rotatably mounted on the hub spindle 1 is acted upon in this case by a coaxial compression spring 20 which is conically wound, is applied with its small diameter against the collar part 15b of the brake cone 1 5 and with its large coil end bears inside the brake casing 1 6 against the dog 21 thereof.This compression spring 20 ensures constant application of the brake cone 15 against the coupling member 1 2 in axial direction both during the inoperative condition and during forward pedalling (see Fig. 3).

Fig. 2 shows another embodiment of the invention. This illustration shows above all, in partial section, the design of the hub differing from the abové-described embodiment of the hub according to Fig. 1, whereas the remaining components (not shown) of the freewheel hub are unaltered in respect of the embodiment according to Fig. 1. Accordingly, like.

components are indicated with the same refeg- ence numerals.

With otherwise similar construction, in the embodiment of Fig. 2 the compression spring 20, which presses the brake cone 1 5 with its coupling or inclined-surface teeth 14 axially against the corresponding teeth 1 3 on the coupling member 12, is so designed that coil 20a adjacent the brake cone is fitted on to a coaxial shoulder 15e of the brake cone 1 5 so that the brake cone 15 is not only pressed in axial direction by this spring arrangement, but is also prevented from co-rotation in the manner of a friction brake when, during backward rotation of the driver 7, the inclined gear surfaces 1 3 of the coupling member 1 2 are rotated and are applied against the inclined gear surfaces 1 4 of the brake cone 15; ; the brake cone 15 is then displaced axially and forced into the brake casing 16, thus expanding the latter from inside against the bore of the hub shell 10.

The above-described embodiments of a freewheel hub with a back-pedalling brake device according to Figs. 1 and 2 enable a simple and particularly robust construction of a freewheel hub with a very effective backpedalling brake device to be achieved, in which case the hub shell may have a smooth bore without a scraper or wiper edge; similarly, apart from the fluting in the operative zone of the brake cone, the brake casing is designed to be smooth inside, and likewise the spindle carrying the hub is made smooth, i.e. without steps or grooves.

Claims (6)

1. A freewheel hub with a back-pedalling brake device for bicycles or the like, comprising a driver, a hub shell, a grip-roller coupling between the driver and the hub shell, a brake casing inside the hub shell provided with a uniformly smooth inner bore, which brake casing can be expanded by means of a cone axially displaceable via inclined gear surfaces and provided with a friction device against the brake casing, the brake casing being prevented from independent rotation by means of radially inwardly directed dogs acting against stop surfaces of a bearing part secured on the hub spindle, wherein the spindle carrying the hub components is made uniformly smooth, and wherein both the brake cone mounted directly on the hub spindle, on the circumferential part thereof engaging into the brake casing, and the brake casing on its inside in the engagement zone of the brake cone have an axially directed fluting.

2. A freewheel hub as claimed in claim 1 wherein a compression spring is disposed axially between the brake cone and the brake casing inside the brake casing, which compression spring bears at one end against the retaining dog of the brake casing and, at the other end, against a collar part of the brake cone.

3. A freewheel hub as claimed in claim 2, wherein the axially disposed compression spring has a conical coil cross-section.

4. A freewheel hub as claimed in claim 1, wherein the friction device on the brake cone comprises a loop spring encircling a collar part of the brake cone and having radially projecting spring ends engaging in one of a plurality of slots in the brake casing.

5. A freewheel hub as claimed in claim 3, wherein the friction device on the brake cone is formed by the conical compression spring disposed inside the brake casing and bearing at one end against the retaining dog, the other coil end of said compression spring encircling the brake cone at a shoulder of the collar part by frictional resistance.

6. A freewheel hub substantially as hereinbefore described with reference to and as shown in Figs. 1 and 3 or Figs. 2 and 3 of the accompanying drawings.