A DEVICE FOR THE CORRECT POSITIONING OF THE LOWER STEERING SHAFT ON THE STEERING-BOX PINION AND ON THE UPPER SHAFT

Abstract: The subject of the present invention is a device for the correct positioning of the lower steering shaft on the steering-box pinion and on the upper steering shaft respectively, comprising a bush (1) with a reference tooth (2) which, as well as ensuring the correct positioning of the clamping screw (4), also simultaneously ensures the secure clamping of the screw (4) for the correct connection of the aforementioned members. A bush without the reference tooth, which is replaced by a bracket welded to the fork, is envisaged as a variant of the invention.

Description: The present invention relates to a device for the correct positioning of a steering shaft to a steering-box pinion according to the preamble of claims 1 and 2. It is known that the connection of the aforementioned members is normally achieved by the tightening of a screw which connects the universal-joint fork of the lower steering shaft to the steering-box pinion and to the upper shaft. This operation is not very reliable with a view to the safety of the vehicle since, during the positioning and/or connecting operations described above, the person carrying out the mounting cannot easily see to check reliably whether the clamping screw is engaged exactly in the groove of the steering-box pinion and of the upper shaft. It is also known that the problems described above have been overcome by patent No. 54187B/86 of the same Applicant. The solution described in that document relates to a safety ring for the correct connection of the lower steering shaft to the steering-box pinion and to the upper shaft which, although ensuring on the one hand the perfect positioning of the screw, on the other hand limits the operator's movements in positioning the members. In order to overcome the above-mentioned disadvantages, the present invention provides a device of the type specified above, having the features recited in the characterizing portions of independent claims 1 and 2. The invention also simplifies the mounting of the aforementioned members, the simplicity of mounting being due to the fact that the operator no longer has to carry out the operation of sliding the steering shaft upwards to insert the steering-box pinion. In the following the present invention will be described with reference to the appended drawings, provided by way of non-limiting example, in which: Figure 1 is an exploded view of the detail which is the subject of the present invention, in a first embodiment, that is, with a reference tooth; Figure 2 shows a side view and two sectional views of the detail of Figure 1; Figure 3 is an exploded view of the detail which is the subject of the present invention, in a second embodiment, that is, with a reference bracket welded to the fork; Figure 4 is a section of the detail of Figure 3. With reference to Figures 1 and 2, a fork, indicated 3, has holes 11 and 12 formed in its upper part, into which the lower steering shaft 13 is inserted; holes into which a clamping screw 4 is fitted to connect the fork 3 of the universal joint 14 of the lower steering shaft 13 to the steering-box pinion 5 and to the upper shaft, not shown, are indicated 6 and 7; a nut is indicated 15 and serves for the tightening of the screw 4; a bush, indicated 1, is mounted on a cylindrical shank 8 of the steering pinion 5 by means of a splined hole 9 and is held by a Seeger ring 10 without a groove; a hole formed in the bush 1 is indicated 9a and a groove which enables the passage of the clamping screw 4 is indicated 16; a suitably-shaped reference tooth on the bush 1 is indicated 2 and is arranged to determine the exact position of the fork 3 and thus enable the free passage of the clamping screw 4 through the groove 16 formed in the pinion 5; arms are indicated 17 and 18; a back of the fork 3, against which the reference tooth 2 of the bush 1 abuts to determine the exact position of the clamping screw 4 in the holes 6 and 7 and in the groove 16 of the pinion 5, is indicated 18a. With reference to Figures 3 and 4, the parts described in detail in Figures 1 and 2 are indicated by the same reference numerals, whilst, as a possible variant of the solution described, a C-shaped bracket welded to the fork 3 is indicated 19 and is constituted by an upper part 20 which determines the end of travel of the pinion 5 when it is fitted into the fork 3, thus determining the correct positioning of the screw 4 and the secure clamping of the universal-joint fork 3 of the lower steering shaft 13 to the steering-box pinion 5 and to the upper shaft, as described above. In order to mount the device which is the subject of the present invention correctly, the operator must proceed in the following manner: a) with respect to the first solution described, that is, the bush 1 with a reference tooth 2, the steering box pinion 5, on which the bush 1 is already mounted, is inserted into the fork 3; the clamping screw 4 is then fitted in the holes 6 and 7 and tightened with the nut 15. The clamping of the screw 4 is ensured by the perfect positioning of the reference tooth 2 formed on the bush 1 which is positioned on the back 18a of the fork 3. If the operator does not push the pinion 5, on which the bush 1 is keyed, right to the end, the reference tooth 2 is not positioned on the back 18a of the fork 3 and the holes 6 and 7 are thus not aligned and the anomaly is therefore immediately identified. b) with respect to the second solution described above, however, the operator must proceed in the following manner: the steering box pinion 5, on which the bush 1 is already mounted, is inserted until the cylindrical shank 8 meets the upper part 20 of the bracket 19; the screw 4 is then fitted into the holes 6 and 7 and tightened with the nut 15.

Claims: 1. A device for the correct positioning and/or connection of a steering shaft to a steering-box pinion (5), said steering shaft comprising an upper steering shaft and a lower steering shaft (13) which is connected to a splined cylindrical shank (8) of the pinion (5) by means of a universal joint comprising a fork (3), characterized in that it comprises a split bush (1) having a splined axial hole (9) in which the splined shank (8) of the pinion (5) is engaged and a pair of tangential holes (9a) disposed in tangential alignment with a circumferential groove (16) in the cylindrical shank (8), the bush (1) and the shank (8) of the pinion (5) being fitted into said fork (3); the fork (3) having a pair of aligned holes (6, 7) disposed in alignment with the aligned holes (9a) in the bush (1), a clamping screw (4) being engaged in said groove (16) in the cylindrical shank (8) and extending through the holes (6, 7, 9a) in the fork (3) and the bush (1) to connect and clamp the universal joint to the pinion; said fork (3) having a U-shaped configuration including two arms (17, 18) and a back portion (18a), the bush (1) carrying a reference tooth (2) adapted to abut the back portion (18a) of the fork (3) to define the exact position wherein the holes (6, 7, 9a) in the fork (3) and the bush (1) are aligned for the passage of the clamping screw (4). 2. A device for the correct positioning and/or connection of a steering shaft to a steering-box pinion (5), said steering shaft comprising an upper steering shaft and a lower steering shaft (13) which is connected to a splined cylindrical shank (8) of the pinion (5) by means of a universal joint comprising a fork (3), characterized in that it comprises a split bush (1) having a splined axial hole (9) in which the splined shank (8) of the pinion (5) is engaged and a pair of tangential holes (9a) disposed in tangential alignment with a circumferential groove (16) in the cylindrical shank (8), the bush (1) and the shank (8) of the pinion (5) being fitted into said fork (3); the fork (3) having a pair of aligned holes (6, 7) disposed in alignment with the aligned holes (9a) in the bush (1), a clamping screw (4) being engaged in said groove (16) in the cylindrical shank (8) and extending through the holes (6, 7, 9a) in the fork (3) and the bush (1) to connect and clamp the universal joint to the pinion; a C-shaped bracket (19) being welded to the fork (3) and having an upper part (20) arranged to abut the shank (8) of the pinion (5) to determine the exact position wherein the holes (6, 7, 9a) in the fork (3) and the bush (1) are aligned for the passage of the clamping screw (4). 3. A device according to claim 1 or 2, characterized in that the shank (8) is provided with a smooth reduced diameter end portion extending beyond said bush (1) and further comprising a Seeger ring (10) secured to said smooth end portion to hold said bush (1) on the pinion (5).

Inventors: PINNA, PIERO
Applicants: FIAT AUTO S.P.A.
Application year: 1988
Main classification: B62D1
IPC codes: B62D1, F16D1