DEVICE FOR DETERMINING THE SLACK IN ARTICULATED JOINTS AND FOR MEASURING THE STEERING ANGLES OF MOTOR VEHICLES

Abstract: A device for determining the slack in articulated joints and for measuring the steering angles of motor vehicles, to be positioned in a recess (4) provided in each runway (6) of a vehicle lift, characterised by comprising: a base plate (2) to rest on the bottom of said recess (4), a pair of first actuators (10) arranged parallel to each other and fixed to said base plate along two of its opposing sides, an intermediate plate (12) fixed to the rods of said first actuators (10) and having two opposing edges slidable within guides (14) formed in the bodies thereof, a pair of second actuators (16) arranged perpendicular to the first actuators and fixed to said intermediate plate (12) along two opposing sides, an upper plate (18) fixed to the rods of said second actuators (16) and having two opposing edges slidable within guides (20) formed in the bodies thereof, a platen (26, 34) resting on said upper plate (18) via ball supports, means (32) for locking said platen (26, 34) to said upper plate (18), and means (30) for maintaining the position of said plate (26, 34) elastically centered with respect to said upper plate (18).

Description: Device for determining the slack in articulated joints and for measuring the steering angles of motor vehicles This invention relates to a device for determining the slack in articulated joints and for measuring the steering angles of motor vehicles. In motor vehicle service stations devices are provided for measuring the slack in the vehicle articulated joints. These devices comprise a lower plate and an upper plate movable horizontally relative to the lower plate in the two perpendicular directions. These devices are generally installed in pairs on a vehicle lift, the lower plate being fixed to the corresponding runway and the upper plate supporting a wheel of the vehicle which is to be checked and which has previously been driven onto the lift. To determine the presence of any slack in the articulated joints of the steering system and to measure its extent, the upper plate is made to move relative to the fixed lower plate while observing the behaviour of the vehicle during these movements, viewing from below with the aid of an electric lamp. A drawback of this known device is that it has a rather large height (about 7 cm) , and as it is generally installed permanently on the vehicle lift this can in practice be used only for this purpose. Circular ball plates are also known for measuring the SUBSTITUTESHEET suspension geometry and the wheel steering angles. These are also generally mounted on the vehicle lift runways in suitable recesses provided within them, so restricting their use to this one purpose because of their particular configuration and the nature of the functions performed. Hence those vehicle service stations equipped both for determining slack and for measuring steering angles must necessarily be provided with two vehicle lifts or in any event two separate stations, one equipped with the accessories of one type and the other equipped with the accessories of the other type, with obvious cost and space considerations. Alternatively, the accessories for the two different measurements could be mounted interchangeably on one and the same vehicle lift, but this would require a series of operations for installing the appropriate accessories before effecting a given type of measurement and their removal after making this measurement. An object of the invention is to provide a device which can be used both for determining the slack in articulated joints and for measuring the steering angles of motor vehicle wheels. A further object of the invention is to provide a device SUBSTITUTE SHEET which can be converted from one to the other form for the appropriate use. A further object of the invention is to provide a device in which this conversion can be effected with the maximum speed and ease by the operator. A further object of the invention is to provide a device which can be mounted on conventional vehicle lifts without thereby restricting them to this specific use. A further object of the invention is to provide a device which combines multi-purpose with compact construction, safe and reliable operation and minimum space requirement such as to enable it to be accomodated within the recess generally provided in the runways of vehicle lifts. A further object of the invention is to provide a device with enables the upper plate to be subjected to 90° or 45° movements, on the basis of the particular measurementes to be made. These and further objects which will be apparent from the description given hereinafter are attained according to the invention through a device for determining the slack in articulated joints and for measuring the steering angles of motor vehicles, to be positioned in a recess provided in each runway of a vehicle lift, characterised by comprising: SUBSTITUTESHEET - a base plate to rest on the bottom of said recess, - a pair of first actuators arranged parallel to each other and fixed to said base plate along two of its opposing sides, - an intermediate plate fixed to the rods of said first actuators and having two opposing edges slidable within guides formed in the bodies thereof, - a pair of second actuators arranged perpendicular to the first actuators and fixed to said intermediate plate along two opposing sides, - an upper plate fixed to the rods of said second actuators and having two opposing edges slidable within guides formed in the bodies thereof, - a platen resting on said upper plate via ball supports, - means for locking said platen to said upper plate, and - means for maintaining the position of said plate elastically centered with respect to said upper plate. The present invention is further clarified with reference to the enclosed sheets of drawings in which: Figure 1 is a plan view of a device according to the invention fitted into the recess in the runway of a vehicle lift. Figure 2 is a plan view thereof without the upper plate or SUBSTITUTESHEET the overlying platen. Figure 3 is a plan view thereof without the platen. Figure 4 shows the device in the same view as Figure 1 but with a circular instead of octagonal platen, Figure 5 is an enlarged longitudinal section therethrough on the line V-V of Figure 1 , and Figure 6 is an enlarged cross-section therethrough on the line VI-VI of Figure 1. As can be seen from Figure 1 the device according to the invention comprises a base plate 2 in the form of a regular octagon of dimensions suitable to allow it to be accommodated within the recess 4 provided in each runway 6 of a vehicle lift. The base plate 2 comprises two rectilinear slots 8, the purpose of which will be apparent hereinafter. Two actuators 10 in the form of two hydraulic cylinders are applied to the base plate 2 in proximity to those opposing sides thereof parallel to the two slots 8 , and have their rods connected to a substantially rectangular intermediate plate 12 of smaller surface area than the base plate 2. It is movable horizontally relative to said base plate 2 under the control of the two cylinders 10. For this purpose the mutually facing lateral surfaces of these are provided with guides 14 engaging two opposite edges of the SUBSTITUTESHEET plate 12 in order to guide it in its translational movements, which are therefore parallel to the axis of the cylinders 10. A further two actuators 16 in the form of hydraulic cylinders are fixed to the plate 12 on the two sides not engaged in the guides 14, and have their rods connected to a third rectangular plate 18, which in this manner can slide horizontally in a direction perpendicular to the direction in which the underlying intermediate plate 12 slides and is guided in its movements by the engagement of two of its lateral edges in corresponding guides 20 formed in the body of the cylinders 16. This upper third plate 18, which is smaller than the underlying intermediate plate 12 and comprises a central circular hole 22, is provided on its upper surface with a plurality of ball supports 24, on which there rests an octagonal platen substantially analogous to the base plate 2 and forming the support platen for a wheel of the motor vehicle. From the centre of the lower surface of the octagonal platen 26 there projects downwards a mushroom-shaped appendix 28, the head of which has a diameter greater than the diameter of the hole 22 to allow said platen 26 to undergo substantial movements relative to the underlying rectangular SUBSTITUTESHEET plate 28, while preventing its complete separation. In addition, between the mushroom-shaped appendix 28 of the octagonal platen 26 and the underlying rectangular plate 18 there are interposed two pairs of spiral springs 30, the purpose of which is to maintain the two plates 26 and 18 mutually centered elastically in the absence of external forces. Within the rectangular plate 18 there are also provided two small cylinders 32 with their axis perpendicular to this plate and with their rod emerging upperly and engaging in a corresponding hole provided in the overlying platen 26 and facing said rod when said platen 26 is centered with respect to the plate 18. The device of the invention also comprises a circular platen 34, which can replace the octagonal platen 26. This circular platen 34 is also provided with a lower mushroom- shaped appendix 28 and holes 36 to be engaged by the locking cylinders 32, and is also provided with a graduated edge 36, with which there is associated a pointer 38 rigid with the base plate 2. The device of the invention further comprises a plurality of sensors and connectors, which enable the device to be connected to a small control centre preferably applied SUBSTITUTE SHEET below the runway 6 in which the device is installed, and also enable the operating cycle described hereinafter to be correctly executed. As the control centre is constructionally and operationally of conventional type it is not shown on the drawings. It comprises a vessel, a pump and a plurality of solenoid valves, and miscellaneous controls and regulators depending on the types of motor vehicles concerned. All the components are miniaturized, and because they are housed below the runway 6 they substantially limit the connections to the device of the invention. In practice only one control centre is required for the two devices mounted in the two runways of the vehicle lift; two connection pipes are therefore provided between the control centre and the device mounted in the same runway 6, plus a further two connection pipes between the control centre and the device mounted in the other runway of the vehicle lift. Finally, an electrical supply is required for the control centre. To determine the existence of possible slack, two devices of the aforedescribed type are firtly positioned on the vehicle lift in the recesses 4 generally provided in its two runways 6. During this, care must be taken that each device is positioned such that the two cylinders 10 rigid with the base plate 2 have their axis perpendicular to the SUBSTITUTESHEET longitudinal axis of the corresponding runway. In order for the measurements to be correctly effected, the two devices must be positioned at a distance apart equal to the wheel gauge of the vehicle under measurement, hence as the runways of a vehicle lift are generally wide enough to allow the same lift to be used for vehicles with different wheel gauges, each device is made transversely movable within the corresponding recess 4 of the runway 6 either manually or mechanically. In the first case a downwardly directed appendix 40 is fixed to the octagonal base plate 2 to engage in holes provided in the base 44 of the recess 4 corresponding to the different transverse positions which the device can assume within the recess. In the second case a transverse cylinder 42 is positioned below the base 44 of the recess 4 so that its rod engages in the appendix 40 which projects lowerly from the base plate 2 and passes through a transverse slot 46 provided in said base 44. In either case there is no problem in hydraulically feeding the cylinders 10, 16 and 32 whatever the position of the base plate 2 within the recess 4, because the slots 8 provided in said plate enable the feed pipes to pass through it whatever its position. Because of the fact that, as will be apparent SUBSTITUTESHEET hereinafter, the device of the invention must be able to be positioned within the recess 4 in two separate positions rotated through 45°, the appendix 40 should be situated exactly at the centre of the plate 2. To determine the existence of slack in a motor vehicle, the two devices contained in the recesses 4 of the two runways 6 must firstly be set to the correct distance apart by transversely adjusting at least one device manually or mechanically. Having completed this positioning, the vehicle is driven onto the runways of the vehicle lift and positioned such that its two front wheels lie exactly at the centre of the platens 26 of the two devices, so that these are locked relative to the underlying plates. Then, after deactivating the two cylinders 32 and hence releasing the platen 26 from the plate 18, the two pairs of cylinders 10 and 16 are caused to undergo small longitudinal and/or transverse movements, to determine whether slack exists or not. This determination is generally effected with the aid of a lamp which upwardly illuminated the region to be checked and is provided with pushbuttons to control the cylinders 10 and 16. If the wheels are to be subjected to small pulse SUBSTITUTE SHEET movements at 45° to the longitudinal axis of the runway, each device can be positioned in its respective recess rotated through 45°. Under these conditions it is necessary to operate only one of the two pairs of cylinders 10 or 16 to obtain the pulse movements in the required direction. In this respect, in such cases the device of the invention could be formed with only one pair of cylinders 10 or 16 or with only one of the plates 12 or 18. If it is also required to determine the wheel steering angle the octagonal platen 26 can be replaced by the circular platen 34, onto which, after being locked to the plate 18 by the cylinders 32, the corresponding steered wheel of the vehicle is driven. The plate 34 is then released and the wheel is steered and the angle or rotation of said plate 34 is read by the position of the pointer 38 on the graduated edge 36. Basically, because of the combination of the slack determination and steering angle measurement instruments into a single unit and because of the original arrangement and coordination of the various interacting parts, the device of the invention enables the conventional method to be considerably modified and considerable advantages to be achieved, and in particular: SUBSTITUTE SHEET - slack determination and steering angle measurement on a motor vehicle can be effected at choice with a single device without having to move the vehicle from its position on the vehicle lift, - the device is multi-purpose while being of extremely small overall size, allowing it to be contained within the conventional recesses provided in the runways of the vehicle lift, - it can be removed from the vehicle lift, which is therefore not constrained to this specific use, - it can be used without distinction in either the right or left runway, - it enables the upper platen to be moved not only parallel and perpendicular to the runways but also at an angle of 45° thereto, - it can be used for vehicles of practically any wheel gauge, and - it is simple to install and does not require external connections other than to the electricity supply. SUBSTITUTE SHEET

Claims: C L A I M S 1. A device for determining the slack in articulated joints and for measuring the steering angles of motor vehicles, to be positioned in a recess (4) provided in each runway (6) of a vehicle lift, characterised by comprising: - a base plate (2) to rest on the bottom of said recess (4) , - a pair of first actuators (10) arranged parallel to each other and fixed to said base plate along two of its opposing sides, - an intermediate plate (12) fixed to the rods of said first actuators (10) and having two opposing edges slidable within guides (14) formed in the bodies thereof, - a pair of second actuators (16) arranged perpendicular to the first actuators and fixed to said intermediate plate (12) along two opposing sides, - an upper plate (18) fixed to the rods of said second actuators (16) and having two opposing edges slidable within guides (20) formed in the bodies thereof, - a platen (26,34) resting on said upper plate (18) via ball supports, - means (32) for locking said platen (26,34) to said upper plate (18) , and - means (30) for maintaining the position of said plate SUBSTITUTE SHEET (26,34) elastically centered with respect to said upper plate (18) . 2. A device as claimed in claim 1 , characterised in that the base plate (2) is in the shape of a regular octagon, the distance between its opposing sides being substantially equal to that dimension of the recess (4) measured along the longitudinal axis of the runway (6) . 3. A device as claimed in claim 1, characterised in that the base plate (2) can be moved transversely within the corresponding recess (4) . 4. A device as claimed in claim 3, characterised in that the base plate (2) is provided with at least one downwardly directed appendix (40) engagable within holes provided in the base (44) of the recess (4) . 5. A device as claimed in claim 3, characterised in that the base plate (2) is provided with at least one downwardly directed appendix (4) passing through a transverse slot (46) provided in the base (44) of the recess (4) and engaged by an actuator (42) positioned transversely below said base (44) . 6. A device as claimed in claim 3, characterised in that the base plate (2) comprises at least one trasverse slot (8) through which the feed pipes for said first and second actuators (10,16) and said locking means (32) can pass SUBSTITUTE SHEET whatever the transverse position of said plate (2) within the corresponding recess (4) . 7. A device as claimed in claim 1, characterised in that the first and/or second actuators (10,16) consist of hydraulic cylinder-piston units. 8. A device as claimed in claim 1, characterised by comprising means (28,22) for limiting the horizontal movements of the platen (26,34) relative to said upper plate (18). 9. A device as claimed in claim 1, characterised in that the upper plate (18) comprises a central substantially circular aperture (22) in which there engages an appendix (28) projecting from the lower surface of said platen (26,34) . 10. A device as claimed in claim 9, characterised in that the appendix (28) is substantially of mushroom shape, with the diameter of its head greater than the diameter of the aperture (22) provided in the upper plate (18) . 11. A device as claimed in claim 1, characterised by comprising at least one actuator (32) of substantially vertical axis applied to the upper plate (18) and engaging said platen (26,34) to lock it to said upper plate on command. SUBSTITUTE SHEET 12. A device as claimed in claim 1, characterised in that springs (30) are interposed between said platen (26,34) and said upper plate (18) to maintain them in a mutually centered position in the absence of external forces. 13. A device as claimed in claim 1, characterised by comprising a control centre for the actuators (10,16,32,42) which is common to two devices applied to the two runways (6) of the vehicle lift. 14. A device as claimed in claim 1, characterised in that the platen (26) is in the shape of a regular octagon. 15. A device as claimed in claim 1 , characterised in that the platen (34) is of circular shape. 16. A device as claimed in claim 15, characterised in that the platen (34) is provided with a graduated edge (36) with which there is associated a pointer (38) rigid with the base plate (2).

Inventors: ROSSATO ERIDE, ROSSATO, ERIDE
Applicants: ROSSATO ERIDE, ROSSATO, ERIDE
Application year: 1993
Main classification: G01B5
IPC codes: B62D5, B62D15, B62D17, G01B5, G01M17