DEVICE FOR ADJUSTING A BOWDEN CABLE

Abstract: The invention relates to a device for adjusting in a rest situation the mutual position of an inner and an outer cable (2, 3) of a Bowden cable (4) which is operable between a rest position and at least one active position as soon as a variation has occurred in respect of one or more points of engagement of the Bowden cable, or a change in length has occurred in at least one of the cables. Fixed to the inner cable (2) is a support element (5) which co-acts with a stop (6) connected to a frame. A pressure spring (8) is arranged between support element (5) and outer cable (3). Fixation means (9) are able to lock the sleeve (10) in a new position.

Description: DEVICE FOR ADJUSTING A BOWDEN CABLE The invention relates to a device for adjusting the mutual position of an inner and outer cable of a Bowden cable in a rest situation. A Bowden cable is usually used for remote operation 5 of a mechanical element. Examples hereof are the opera¬ tion of a cycle brake, the operation of a cycle gear, the operation of a hand brake in a car and the operation of the clutch plates in a car. A problem in the use of a Bowden cable is that due to wear of a part of the mechan¬ ic) ical element for operation (for instance wear of brake block or clutch plate) , the position of an operating member, such as for instance a lever, becomes dependent on this wear. Another possibility is that the inner or outer cable undergoes a change in length, wherein stret- 15 ching of the inner cable can for instance be envisaged here. Ease of operation is considerably enhanced when the operating member has fixed positions for the different positions of use of the member for operating. An example hereof is the depressing of a clutch pedal against a stop 20 for declutching and allowing the clutch pedal to rise to an end position for an engaged situation. Another example is the control lever of a derailleur of a modern racing cycle which only has a discrete number of positions instead of a continuous adjustment option. It will be 25 apparent that when the operating member has discrete positions this can result in variation in the position of the member for operating when no correction is made therefor. The German Cffenlegungsschrift DE 31014SS describes a device for lengthening the outer cable of a 30 Bowden cable. Arranged for this purpose on the outer cable is an end fitting which has on the side remote from the outer cable a resilient tongue with a tooth directed towards the inner cable with a perpendicular and an cbiiσue wall * oar . Around the cable is arranged a σuice sleeve which is fixed rigidly on the side remote from the end fitting. The guide sleeve is provided in the vicinity of the tooth with a toothing which co-acts with the tooth and on which the tooth engages resiliently. The sloping surfaces of the tooth and the toothing are herein placed such that the end fitting and the guide sleeve can only be moved apart, while the movement directed toward each other is blocked. Placed between the end fitting and the guide sleeve is a pressure spring which pushes end fit- ting and guide sleeve apart when the inner cable of the Bowden cable becomes longer. In this manner a lengthening of the inner cable is automatically compensated. The present invention has for its object to provide a device for adjusting the mutual position of an inner and an outer cable of a Bowden cable which is operable between a rest position and at least one active position as soon as variations occur in respect of one or more points of engagement of the Bowden cable, or a change in length has occurred in at least one of the cables . The device must preferably function such that variations in the system are automatically compensated. The invention provides for this purpose a device comprising: - a support element which is fixed to the inner cable, and fixed at a position where the inner cable is not enclosed by the outer cable, which support element is displaceable relative to the inner cable at least in the longitudinal direction away from the outer cable, - a biasing element received between the support element and the outer cable for generating a bias pressing apart the support, element and the outer cable, - a frame for mounting the Bowden cable, the operating means of the Bowden cable and the means for operating by the Bowden cable, which frame is provided with a stop for co-action with the support element in the rest position of the Bowden cable, and - fixation means for fixing the outer cable or the inner cable relative to an engagement point of the Bowden cable in an active position of the Bowden cable. Because the support element will lie against the stop of the frame, freedom of movement between the inner and the outer cable is created close to the support element when there are variations in the system. If the biasing element is sufficiently powerful it can thereby expand. The new position occupied by the biasing element can now be locked by the fixation means. In a preferred embodiment the fixation means are formed by an element provided with a toothing, which element is fixedly connected to the outer cable, and at least one ratchet engageable in the teeth, which ratchet is connected to the frame. The ratchet is preferably placed under a bias directed toward the toothed element. In a preferred embodiment the toothing also comprises rise surfaces directed to one side. These steps result in freedom of movement in one direction, whereby variations in length of the biasing element can be maintained. In another preferred embodiment the ratchet can be lifted out of the toothing by means of disengaging means. Due to the one-sided compensation direction of the fixa¬ tion means the maximum compensation potential is limited. It is conceivable after prolonged use of the Bowden cable for a relatively large compensation to be performed manually on the side of the operating member or the member for operating. In the ideal situation the fixation element can then begin to function again from the start- ing position. It is however necessary for this purpose that the ratchet which is displaced to one side over the toothing is again placed at the beginning of the tooth¬ ing. This is only possible when the ratchet can be re¬ leased relative to the toothing. Another example of a situation in which this may be desirable is for instance during changing of brake blocks. The fixation means have compensated for the change in length of the worn brake blocks, but must be placed once again in the zero posi- tion when the new brake blocks have the same dimension as the worn brake blocks originally had. Another situation in which release of the ratchet is desirable is during fitting of the Bowden cable with the device according to the invention. Release of the ratchet can take place manually by means of a manually operable member or by a stop arranged in the device (for instance incorporated in the operating member) . Such a variant is for instance useful in operating a hand brake of a car which can become jammed in an active position, which is possible when it is frozen fast. An entirely different preferred embodiment relates to a device wherein the position of the support element on the inner cable is adjustable. If for instance the support element is only slidable over the cable in one direction due to the specific form of the contact surface between the support element and the inner cable, it becomes possible to combine the function of the support element with that of the fixation means. Variations in length of the biasing element can then be absorbed by displacing the support element relative to the inner cable. This variant can be very useful in adjusting the inner cable. Yet another preferred embodiment of the device is characterized in that the biasing element is formed by a pressure spring, which pressure spring is placed parallel to the Bowden cable for at least part of the length. If a relatively large compensation length of the device is desired, it is important that the bias produced by the biasing element remains located within certain limits despite the length variation thereof. This can be real¬ ized by giving the biasing element a relatively long form. The spring constant of a long spring in any case remains relatively constant over large displacement lengths of this spring. A drawback of a long biasing element is that the device acquires a relatively long construction length. It is however possible by means of this preferred embodiment to allow the biasing element to run parallel to the Bowden cable. The spring can herein be placed on the outside of the outer cable and also supports on the outside of the outer cable. In this case it is recommended to enclose the biasing element with a protective housing such as a flexible sleeve. It is also possible to place the pressure spring between the inner and outer cable, in which case the outer cable will have to take a wider form along a determined length. Another preferred embodiment of the device comprises a fixation element for fitting on the outside of an elongate body with a substantially constant cross sec¬ tion, which element is formed by a wire structure of at least one wire running round the elongate body, wherein the object for fixing relative to the elongate body is placed at one end side of the wire structure and a pres¬ sure element is placed on the opposite end side of the wire structure to exert a force directed to the wire structure in order to discontinue the fixing action of the clamping element. The present invention will be further elucidated with reference to the non-limitative embodiments of the device and the fixation element according to the inven¬ tion shown in the following figures. Herein: fig. 1 shows a cross section through a schematically depicted adjustment device according to the invention, fig. 2 shows a cross section through the adjustment device of fig. 1 in a variant ready for production, and fig. 3 shows a cross section through a variant of the adjustment device with specific fixation element. The adjustment device 1 shown in fig. 1 for adjust¬ ing the mutual position of an inner and outer cable 2,3 of a Bowden cable 4 is shown in a rest position. Fixed to inner cable 2 is a support element 5 which co-acts with a stop 6 connected to a frame (not shown) . In this figure the stop 6 is connected to the frame (for instance with interposing of operating means) with interposing of a sleeve 7 running round inner cable 2. The adjustment device 1 shown in this figure is situated in a rest position since support element 5 lies against stop 6. In an active position the support element will be released from the stop 6. A pressure spring 8 is arranged between support element 5 and outer cable 3. Finally, the figure also shows fixation means 9 which are formed by a toothed sleeve 10 forming part of outer cable 3 and ratchets 11 co-acting therewith. The ratchets 11 are under a bias directed to the toothed sleeve 10 and engage in the toothing arranged in sleeve 10, thus preventing the toothed sleeve 10, and thus also outer cable 3, from being moved to the stop 6, since an actuating force F in this figure will exert a relative force on outer cable 3 relative to inner cable 2 which is directed toward the stop 6 parallel to the Bowden cable 4. Only in the shown rest position, when support element 5 lies against stop 6 is the device "recalibrated" . In the case of increased play between inner cable 2 and outer cable 3 the pressure spring 8 can then displace the toothed sleeve 10 relative to stop 6. After the displacement the ratchets 11 will lock the toothed sleeve 10 in the new position. After fitting of the adjustment device and re-ad¬ justment of the engagement points (not shown) of the Bowden cable, it may be desired to place the adjustment device 1 in a starting position in which the toothed sleeve 10 is situated as close as possible to stop 6. It is necessary for this purpose for the ratchets 11 to be releasable from the toothed sleeve 10. This can be real¬ ized for instance by manual release of ratchets 11 but this can also be realized in other manner as already described above. Figure 2 shows a variant 12 of the schematically shown adjustment device 1 of fig. 1 which is ready for production. Similar components are herein designated with the same numerals. Figure 3 shows an adjustment device 18 in which a wire structure 19 is arranged which herein functions as a unilaterally operating fixation means. The device func- tions as according to the device shown in fig. 1 and 2 and corresponding parts are also similarly designated. The wire structure 19 engages on a widened part 20 of outer cable 3. For good operation it is important herein that the widened part 20 is sufficiently form-retaining in cross section at the position of the engagement of the wire structure. The wire structure 19 is connected on one side to an earth ring 21 which is fixedly connected to the earth 16. The stop 6 is also fixedly connected to the earth 16 so that the distance between earth ring 21 and stop 6 remains constant. The wire structure 19 is con¬ nected at the other end side to the disengaging member 17. Using this device 18 it is possible in the shown rest position by means of the pressure spring 8 (see above the corresponding action of figure 1) to move the outer cable 3 of Bowden cable 4 further away from the support element 5 under the influence of the pressure spring 8. The adjustment device 18 does not obstruct this freedom of movement. The wire structure 19 does however block a movement directed toward support element 5 of the outer cable 3 of Bowden cable 4 and thus also of the widened part 20 which forms part of outer cable 3. In order to place the adjustment device 18 in a starting position in which the widened part 20 of outer cable 3 is situated as close as possible to stop 6, it is necessary to disengage the wire structure 19. Disengaging of the adjustment device 18 takes place by exerting on disengaging member 17 a force directed toward the earth ring 21. During exertion of such a force it will be possible to move outer cable 3 freely in the direction of stop 6. For a simple disengaging it is possible to provide the disen¬ gaging member 17 with a control button, but it is also possible for this purpose to include an automatic stop in a member operating Bowden cable 7 or a member operated by Bowden cable 4. *****

Claims: CLAIMS 1. Device for adjusting in a rest situation the mutual position of an inner and an outer cable of a Bowden cable which is operable between a rest position and at least one active position as soon as a variation has occurred in respect of one or more points of engage¬ ment of the Bowden cable, or a change in length has occurred in at least one of the cables, wherein the device comprises: - a support element which is fixed to the inner cable, and fixed at a position where the inner cable is not enclosed by the outer cable, which support element is displaceable relative to the inner cable at least in the longitudinal direction away from the outer cable, - a biasing element received between the support element and the outer cable for generating a bias pressing apart the support element and the outer cable, - a frame for mounting the Bowden cable, the operating means of the Bowden cable and the means for operating by the Bowden cable, which frame is provided with a stop for co-action with the support element in the rest position of the Bowden cable, and - fixation means for fixing the inner cable or the outer cable relative to an engagement point of the Bowden cable in an active position of the Bowden cable. 2. Device as claimed in claim 1, wherein the fixa¬ tion means are formed by an element provided with a toothing, which toothed element is fixedly connected to the outer cable, and at least one ratchet engageable in the toothing, which ratchet is connected to the frame. 3. Device as claimed in claim 2, wherein the ratchet is placed under a bias directed toward the toothed ele¬ ment. 4. Device as claimed in claim 2 or 3 , the toothing of which comprises rise surfaces directed to one side. 5. Device as claimed in any of the claims 2-4, wherein the ratchet can be lifted out of the toothing by means of disengaging means. 6. Device as claimed in any of the foregoing claims, wherein the position of the support element on the inner cable is adjustable. 7. Device as claimed in any of the foregoing claims, wherein the biasing element is formed by a pressure spring, which pressure spring is placed parallel to the Bowden cable for at least part of the length. 8. Device as claimed in any of the foregoing claims, wherein the device comprises a fixation element which is formed by a wire structure of at least one wire running round the elongate body, wherein the object for fixing relative to the elongate body is placed at one end side of the wire structure and a pressure element is placed on the opposite end side of the wire structure to exert a force directed to the wire structure in order to discon¬ tinue the fixing action of the clamping element. 9. Device as claimed in claim 8, wherein the wire structure is formed by interweaving a plurality of wires running round the elongate body.

Inventors: OLDE HEUVEL BERNARDUS JOHANNES, OLDE HEUVEL, BERNARDUS, JOHANNES, MARIA
Applicants: OLDE HEUVEL BERNARDUS JOHANNES, VEER KABEL B V V D, OLDE HEUVEL, BERNARDUS, JOHANNES, MARIA, VAN DER VEER KABEL B.V.
Application year: 1996
Main classification: F16C1
IPC codes: F16B7, F16C1