HK1072798B - End connection device for an operating cable, with system for ensuring correct assembly - Google Patents

Description

The present invention relates to an end connection device, or terminal device, for an operating cable of the so-called push-pull type according to the preamble of claim 1. An end connection device having the characteristics set forth in the preamble of Claim 1 is known from US-A-4478531.

These devices are often used, especially in the automotive field, for connecting one end of an operating cable to a control member, such as the control lever of the gearbox of a motor vehicle.

The terminal device must allow a jointed connection between the end of the cable and the control member. For this purpose the terminal device, which is usually assembled on the control member, for example at one end of the gear shift lever, has a spherical seat into which the ball head of a pin attached to one end of the operating cable is to be snap-engaged. A releasable connection between the cable and the control member is thus achieved.

German Patent Application DE 198 13 721 A1, for example, discloses a terminal device designed to reduce the force required to insert the ball head of the pin associated to the control lever into the spherical seat formed in the hollow terminal, without thereby reducing the disassembly force and so risking causing the ball head to disengage from its seat during operation. To this end, this known device comprises:

• an outer body connected to the operating cable by a connection rod and having an opening arranged perpendicularly to the rod;
• a ball headed pin assembled on the end of the control lever;
• a sleeve inserted into the opening of the outer body and having at least two first recesses and two second recesses defining a first position and a second position, respectively;
• a bush slidably mounted in the sleeve and having a spherical seat for accommodating the ball head of the pin; the bush being provided with elastic catches for engaging in the recesses of the sleeve in order to lock the bush in the abovementioned two positions inside the cavity of the terminal body.

With the bush in the first position, the spherical seat can expand, because of the presence of slits, to snap-engage the ball head of the pin. When the bush is moved into the second position, the whole portion of bush forming the spherical seat is contained in the sleeve inside the terminal body, and is therefore now unable to expand to allow the ball head to disengage from its seat.

According to this known arrangement, therefore, the terminal can adopt a pre-assembled condition, in which the ball head is received in the associated seat in the bush, and the bush is held in the terminal body by its own catches engaging in the abovementioned first recesses. During assembly, however, this represents a disadvantage, because if a terminal is left in the pre-assembled condition it can erroneously be assumed by the operator to be in the final assembled condition, with the inevitable consequence that the cable will come out of the control member as soon as the cable is operated in normal use.

It is an object of the present invention to provide an end connection device for an operating cable that will retain the advantages of the prior art discussed above but that cannot be mistakenly left in the pre-assembled condition.

This and other objects are achieved according to the invention by virtue of an end connection device having the features defined in Claim 1.

Further features and advantages of the device according to the invention will result clearly from the detailed description which follows, with reference to the accompanying drawings, in which:

• Figure 1 is a perspective view, sectioned on an axial plane, showing part of an end connection device according to the invention, in the pre-assembled condition;
• Figures 2 and 3 are views in axial section of the device of Figure 1, in the pre-assembled condition and final assembled condition, respectively; and
• Figures 4 and 5 are perspective views of a bush and an outer body, respectively, that form part of a device according to the invention.

Referring to the figures, an end connection device according to the present invention is generally indicated 10. The device 10 comprises an outer body 11 intended to be connected in a manner known per se, for example by a connection rod (not shown), to one end of an operating cable (also not shown). The body 11, which is preferably formed by plastic moulding, has a central through opening 12 suitable for receiving at a (lower) end a bush 13 and closed at the other (upper) end by a cap or cover 14 (shown in Figures 2 and 3). The body 11 is advantageously over-moulded onto the connection rod, which is generally made of metal and is arranged perpendicular to the axis of the opening 12.

The bush 13 has at its lower end a spherical seat 15 suitable for receiving and snap-engaging, in a manner known per se, a ball head 16 of a pin 17 attached to a control member (not shown), such as the control lever of a motor vehicle gearbox. The seat 15 is bounded at its lower end by a circumferential edge 18 of slightly smaller diameter than that of the ball head 16. Below the circumferential edge 18, the bush 13 forms a lead-in portion 19 which has a tapering inner surface 20. In order to insert the head 16 into the seat 15 the lead-in portion 19 must therefore be expanded elastically, particularly at the circumferential edge 18. For this purpose a series of notches 21 are formed in the portion 19 which are oriented vertically, that is in the direction in which the head 16 is inserted into the bush 13, thereby dividing the portion 19 into elastically deformable segments.

An upper portion of the bush 13 forms an annular protuberance 22 projecting radially from the outer surface of the bush for snap-engaging with a series of ramp-shaped projections 23 provided on the internal surface of the cavity 12 of the body 11. Once again, there are formed in the upper portion of the bush 13, which forms the protrusion 22, a series of notches 24 oriented vertically, that is in the direction in which the bush slides into the cavity 12, thereby dividing this portion into elastically deformable segments. In this way, when the bush 13 is pushed up into the cavity 12, starting from the position shown in Figure 2, the deformable segments of the upper portion of the bush bend radially inwards due to the protuberance 22 sliding over the ramp surface of the projections 23 on the body 11, until the protuberance moves past the projections 23. In this position (Figure 3), corresponding to the assembled condition of the device, the bush 13 is locked axially downwards in the cavity 12, as well as the ball head 16 is locked axially in the seat 15 of the bush.

The body 11 also forms at the top end of the cavity 12 a series of protrusions 25 projecting radially inwards and defining an upper limit position for the bush 13 in cooperation with the annular protuberance 22 of the bush.

Clearly, the projections 23 on the body 11 can be formed as a single annular projection running all the way around the circumference of the cavity 12. The same applies for the protrusions 25.

In order to prevent the connection device from being erroneously left in a pre-assembled condition in which the ball head 16 is received in the seat 15, but the bush 13 is not fully inserted into the cavity 12 and therefore does not ensure that the head 16 is locked in its seat, according to the invention the bush 13 is provided with an elastically deformable element 30, which in its undeformed condition extends into the spherical seat 15 in such a way as to oppose the insertion of the ball head 16. In the illustrated embodiment, the element 30 consists of four curvilinear arms 31, substantially in the form of circular arcs, formed integrally with the bush 13, which extend radially from the top of the spherical seat 15 and are connected to each other at their lower ends. In the undeformed condition (Figure 2) the elastic element 30 defines an upper abutment surface with which the ball head 16 comes into contact before or as soon as the latter has begun to elastically deform the lead-in portion 19 of the bush 13 by acting on the circumferential edge 18.

The shape and dimensions of the elastic element 30 may of course be varied from those illustrated, provided the element is stiff enough to oppose the insertion of the ball head 16 into the seat 15 unless sufficient force is exerted on the head 16 to move the head and bush assembly into the final assembled position described above, in which the protuberance 22 on the bush snap-engages with the projections 23 of the body 11.

Claims (3)

1. A connection device for connecting one end of an operating cable to a control member, particularly a control lever of a vehicle gearbox; the device comprising an outer body (11) to be attached to the operating cable, having a through opening (12); a pin (17) intended to be connected to the control member and having a ball head (16); a bush (13) arranged to be inserted into the through opening (12) of the body (11) to be locked inside it in a final assembled position and having a snap-action seat (15) for receiving the ball head (16) of the pin (17); and elastically deformable means (30) for elastically opposing the insertion of the ball head (16) into the seat (15); characterized in that said elastically deformable means (30) are provided in the seat of the bush and are configured to assume a first undeformed condition, in which they define an upper abutment surface for the ball head (16) inside the seat (15) so as to elastically oppose the insertion of the ball head into the seat, and a second deformed condition, in which they are pushed by the ball head (16) towards the outside of the seat (15) as a result of the insertion of the ball head (16) into the seat (15).
2. A device according to Claim 1, characterized in that said elastically deformable means (30) are formed integrally with the bush (13).
3. A device according to Claim 1 or 2, characterized in that said elastically deformable means (30) comprise a plurality of curvilinear arms (31) that extend radially inwards from a top portion of the seat (15) and are connected to each other at their lower ends.