GB2041469A - A cycle centre-pull brake - Google Patents

Abstract

A centre-pull cycle brake has two limbs 2, 3 which are connected at their upper ends by a connecting cable 4 which is of a fixed length, and ensures that the brake blocks 9 do not move more than a predetermined distance m apart, under normal operation. When it is necessary to remove the bicycle wheel, a lever 7 provided at the end of limb 2 is flicked over as shown to slacken the cable 4 and enlarge to M the distance between the brake blocks 9 so that the wheel can be passed out between them. The lever 7 carries a gudgeon 6 attached to the end of the cable 4 in a slot 7<3>. In the lowered position of normal use, the gudgeon is retained in a circular recessed portion 2<4> of limb 2. In the position shown, the gudgeon is retained in an indentation 7<5> and against the upper surface of head 2<2> of limb 2. <IMAGE>

Description

SPECIFICATION A cycle centre-pull brake The present invention concerns a centre-pull brake for use on a cycle, e.g. a bicycle or tricycle.

According to the invention, there is provided a cycle centre pull brake having two pivoted limbs each carrying a brake having two pivoted limbs each carrying a brake shoe at one end and having a head at the other end for connection to a connecting cable, wherein one of the said heads has a slot through which the cable passes and a recess at the outboard side of the head for locating a gudgeon attached to the corresponding end of the connecting cable, and wherein a lever is pivoted to the head for movement between two end positions in a plane parallel to the plane of the slot, the lever including an elongate slot for receiving the ends of the gudgeon, and being arranged so that in one end position the gudgeon lies in said recess and the connecting cable is in its tighter condition, and in the other end position the gudgeon is wedged against an external surface of the head and the connecting cable is in a slacker condition.

It will be seen that the lever forms a cable slackening apparatus pivotable about an axis at right angles to the longitudinal extent of the connecting cable. The lever is preferably attached to the left hand limb end.

Preferably, the lever and its slot are arranged so that on movement of the lever away from said one end position, the gudgeon is first disengaged from the recess and, during further movement of the lever towards said other end position, the gudgeon slides along the elongate slot towards an indentation and a heel at the end of the slot, the gudgeon being retained in the indentation by the heel, and further movement of the lever being prevented by wedging of the gudgeon against the external surface of the head.

The lever is preferably formed from sheet material bent into a U-shape with two opposite parallel flanges in each of which an elongate slot is formed. The sides of the head on which the lever is pivoted are preferably flat to correspond with the flat flanges of the lever.

The elongate slot or slots in the lever may have an open portion adjacent the heel through which one end of the gudgeon can be pulled out, so that the gudgeon itself can be turned through 90 . The lever also preferably has an opening in the base of the U-shape through which the gudgeon can be removed once it has been turned through 90 .

The lever may have a grip portion with a friction-promoting surface formation on it.

This grip portion can be held to move the lever from its position during normal operation to its position where it slackens the connecting cable.

The limbs are pivoted on a stirrup which is to be attached to the frame of a cycle. A cylindrical nut with an internal screw thread may be force fitted into the centre of the stirrup so as to leave an abutment head projecting on one side of the stirrup, and a locating boss projecting on the other side. In the case of a front brake, the locating boss fits into a bore in the front fork of the cycle, and a threaded bolt is inserted from the other side of the fork and screwed into the cylindrical nut. In this way, there is no projecting threaded portion on either side of the fork and a neat assembly results. In the case of a rear brake, the locating boss of the cylindrical nut receives the lock nut for locking the brake against the rear frame cross piece.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates in perspective a centre pull brake equipped with cable slackening apparatus according to the invention; Figure 2 illustrates, on an enlarged scale and from the front, the centre pull brake in its normal position of usage, and the position of the brake shoes; Figure 3 is a view similar to that of Fig. 2, after the cable slackening apparatus has been disengaged, to separate the brake shoes for facilitating removal or insertion of a bicycle wheel; Figure 4 is an exploded view illustrating, on an enlarged scale, the separate elements of the cable slackening apparatus; Figure 5 is a partial external view illustrated ing the cable slackening apparatus in a first position;; Figure 6 is a view corresponding to the view of Fig. 5, but showing the apparatus in cross-section; Figure 7 is an external plan view of the apparatus of Fig. 5.

Figure 8 is a view similar to that of Fig. 5, showing the cable slackening apparatus in a second position in which the connecting cable is slackened; Figure 9 shows the apparatus of Fig. 8 partly in cross-section; Figure 10 shows the apparatus, partly in cross-section, in a further position; Figure ii is a front view of the means for fixing the stirrup support of the brake relative to the front fork of the bicycle; and Figure 12 is a transverse cross-section taken along line 11-11 of Fig. 11.

This centre pull brake, with cable slackening apparatus and attachment means is for a bicycle, tricycle, tandem or the like. The brake has a stirrup support 1 which can be fitted on the fork head or rear frame crosspiece, with, at its ends, articulating means and means for restoring two symmetrical limbs 2 and 3 to their mutually separated position, these limbs 2 and 3 being equipped at their ends with brake shoes for clamping brake blocks 9 on the sides of the wheel.

In the upper portion the limbs 2, 3 are prolonged to form arms 2', 3', supporting, at their ends, the ends of a single connecting cable 4, which is connected to a pull cable 5, controlled by the brake lever or handle, by a saddle 0.

One of the arms 2', 31 has a plane-surfaced head 22 at one end with a central slot 23 through which a free section 4' of the cable 4 can pass. A recess 24 shaped as a segment of a circle is located at the lower end of the head 22 and faces the slot 23, to retain a centre cylindrical contact portion 6' of a gudgeon 6 through which cable section 41 extends. The cable is anchored in the gudgeon 6 by a ferrule 42. A lever 7 is pivoted to the head 22 by a pivot pin 8. The lever 7 has a U-shaped cross-section with flanges 7' and 72 which lie one on either side of the head 22. The pin 8 passes through the head 22 above and set back from the recess 24. Symmetrical slots 73, which are open to the outside, are formed on the flanges 71, 72 of the pivotal lever 7. The slots receive opposed ends 62, which are of reduced cross-section, of the gudgeon 6.

It is to be understood that, in the position of normal tension of the cable 4, as illustrated in Fig. 2, with a minimum separation m of the brake shoes relative to the rim J of the wheel concerned, the lever 7 occupies its low position (see Fig. 5) and the gudgeon 6 is held in place as a result of its positioning and centering on the recess 24. The line of action ofthe cable 4 passes across the engaging surfaces of the recess and gudgeon.

To slacken the cable 4, the pivotal lever 7 is turned about pin 8 in the direction of arrow F (Fig. 3). The ends 62 of the gudgeon 6 are entrained by the slots 73, and the central part 6' of the gudgeon is disengaged from the recess 24. On further rotation of the lever 7, the portion 6' slides on the outer profiled face 25 of the plane-surfaced head 22, and moves along the slots 73 until it reaches a position where ends 62 of the gudgeon engage in indented portions 75 of the slots which are slightly set back from a supporting heel portion 75.

During the turning movement of the lever 7, the gudgeon pin 6, is continuously in contact with the slots in the lever and with the surface 25 of the head 22. This ensures a controlled slackening of the cable 4 which, subject to the restoring force to which the limbs 2 and 3 are subjected, enables a maximum separation M of the brake shoes to be obtained (Fig. 3), so as to allow more space for the through passage of the wheel when the latter is to be removed from or reassembled on the bicycle. Moreover, this controlled apparatus enables contact of the brake shoes with the wheel to be avoided in the case of a warped or bent wheel, while at the same time the required braking action is preserved.

It also has to be noted that the opposed slots 73 are cut away opposite to the indented portions 75, and are connected to the profiled, set back surface 77, so as to permit the downward passaege of the ends 62 of the gudgeon 6; followed by the rotation of this gudgeon through 90 , so as to enable it to be outwardly removed through an opening 78 formed on the side face of the said pivotal lever 7, as illustrated in Fig. 10. This is necessary when the cable 4 is being removed from or reinserted in the arm 21 concerned.

This centre pull brake, which is thus equipped with a cable slackening apparatus also comprises means for fixing the stirrup support 1 on the fork head, in the case of a front brake, or on the rear frame cross-piece in the case of a rear brake.

With this in view, the stirrup support 1 (Fig.

11) has a through hole in which the outer milled part 1 0' of a sleeve nut 1 0 can be force fitted. This sleeve 10 projects at its opposite end 102, so as to form an abutment surface. At its inside the sleeve nut 10 has a long recessed portion followed by a screwthreaded part, and a screw 11 can be screwed into this part. The screw 11 is equipped with a cylindrical head 111 having a polygonal recess 112, by means of which it can be gripped.

It is to be noted that the inwardly projecting portion of the sleeve nut 10 forms an--abut- ment surface which enables the sleeve nut to be centred in the hole in the fork head 1 2, in the case of the front brake, or the lock nut to be centred against the rear frame crosspiece in the case of the rear brake. In accordance with this provision it is finally to be noted that attachment of the front or rear brake of the bicycle takes place directly by means of the screw 11, thereby ensuring a better attachment, and the whole assembly has a better appearance, particularly through eliminating the projection of the end of the screw.

Claims (6)

1. A cycle centre pull brake having two povited limbs each carrying a brake shoe at one end and having a head at the other end for connection to a connecting cable, wherein one of the said heads has a slot through which the cable passes and a recess at the outboard side of the head for locating a gudgeon attached to the corresponding end of the connecting cable, and wherein a lever is pivoted to the head for movement between two end positions in a plane parallel to the plane of the slot, the lever including an elongate slot for receiving the ends of the gudgeon, and being arranged so that in one end position the gudgeon lies in said recess and the connecting cable is in its tighter condition, and in the other end position the gudgeon is wedged against an external surface of the head and the connecting cable is in a slacker condition.

2. A brake as claimed in claim 1, wherein on movement of the lever away from said one end position the gudgeon is first disengaged from the recess, and during further movement of the lever towards said other end position, the gudgeon slides along the elongate slot towards an indentation and a heel at the end of the slot, the gudgeon being retained in the indentation by the heel, and further movement of the lever being prevented by wedging of the gudgeon against the external surface of the head.

3. A brake as claimed in claim 1 or claim 2, wherein the elongate slots in the lever have an open portion adjacent the heel through which an end of the gudgeon can be extracted, and wherein the lever also has an opening between the two slots through which the gudgeon can pass once it has been extracted through said open portion and turned through 90 .

4. A brake as claimed in any preceding claim, wherein the lever includes a grip portion which can be held to initiate pivoting of the lever.

5. A brake as claimed in any preceding claim, wherein the limbs are pivoted on a stirrup to be attached to the cycle frame, and the brake includes a cylindrical nut fitted in the stirrup and projecting on one side of the stirrup to form an abutment for the limbs and on the other side of the stirrup to locate the stirrup on a cycle frame, and a bolt having a cylindrical head and a polygonal recess which can be screwed into the cylindrical nut to secure the stirrup to the frame.

6. A cycle centre pull brake substantially as herein described with reference to the accompanying drawings.