Title of Invention

SHORT RADIUS STEERING SYSTEM FOR PARKING VEHICLES

Abstract

SHORT RADIUS STEERING SYSTEM FOR PARKING VEillCLES includes a steering wheel (part no.8), fixed at the rear end, for the front wheel driven vehicles. Driven by a primary hydraulic cylinder (part no.I) the steering wheel moves down in the vertical direction to lift the rear end of the vehicle off the ground, and an auxiliary hydraulic cylinder (part no.II) steers the wheel through a rack and pinion for any inclination to achieve the exact steering angle. For the rear wheel driven vehicles the steering wheel is fixed at the front end. A control system controls the vertical and angular movement of the steering wheel. For heavy vehicles instead of one steering wheel the system includes two or more steering wheels. In another embodiment instead of hydrau~ic cylinders, electric motors or pneumatic cylinders are used.

Full Text

FORM 2. THE PATENT ACT, 1970. COMPLETE SPECIFICATION (SECTION 10) 1. SKIDLESS SHARP STEERING SYSTEM, 2. KODAMKANDETH UKKRU VARUNNY, IV/330 MAN ALUR, TRICHUR DISTTRICT, JCERALA P.C 680617. INDIA. INDIAN The following specification particularly describes and ascertains the nature of the Invention and the manner in which it is to be performed A SKIDLESS SHARP STEERING SYSTEM for installing on motor vehicles, comprising of an additional rear wheel suspended from the rear axle bar, for the front wheel driven vehicles, which can be moved up and down by a hydraulic cylinder. The wheel hits the ground and lifts the rev of the vehicle and thus the vehicle rests on its own front wheels supported by the additional rear wheel This rev wheel is steered by means of a rack and pinion attached to the hydraulic piston rod, on top. The piston rod moves through a slot with two parallel sides, made at the centre of the pinion. This pinion is driven by the rack actuated by an auxiliary hydraulic cylinder. Both the cylinders are controlled by a hydraulic circuit. During the turn the front wheels will be held in the parallel position. The system is intended for steering the vehicle with a very short tuning radius, basically for parking in narrow bays. The system can steer the vehicle even at right angle with the inner front wheel in the “stand still” position, in a difficult situation, in forward and reverse direction. The Invention is more clearly described below with reference to the accompanying drawings. In Sheet ml, figure 1 is an assembly of the system. Part 1 is 1 the main hydraulic cylinder of appro: 70 mm dia and 200 mm stroke used for moving the additional rear wheel up and down. Part 2 is the 8 mm thick MS. Plate support structure attached to the rear axle bar of the vehicle and supporting die main hydraulic cylinder. Part 3 is the rack driving the pinion for steering the wheel. Part 4 is die pinion through which the piston of the main cylinder is moving up and down. Part 5 is die piston of appro: 250 mm length. Part 6 is the bracket carrying the wheel. Part 7 is the axle for the wheel. Part 8 is the additional wheel of appro: 9” (Ma x 5” width, used for steering the vehicle. Part 9 is the clamp on Right side for the M.S. Plate structure, Part 10 is the rear axle bar of the vehicle on which die M.S. support structure Ins been attached. Part 11 is the auxiliary hydraulic cylinder of appro: 60 mm bore for actuating the rack. In sheet no.2. Figure 2 indicates the conventional steering system. The front wheels are mounted on short axles pivoted at A and B. When the axis of these 2 axles are produced, they meet at a point 0 on the straight line passing through die axles of the rear wheels. This point is known as “Instantaneous Centre” ,with respect to which 4 wheels describe 4 concentric Arcs when the vehicle turns. Normally angle AOC is approximately 23 degrees and angle BOD is 20 degree for small cars. The biggest radius ie O B is known as “Turning radius” and this works out to approximately 6 meters, when the distance between the pivot points ie AB is 4 ft and the wheel base AC is 7 ft For a perfect skidless steer the equation is cot θ 1 - cot θ = CD / AC. In sheet no.3, figure 3 indicates the proposed steering system. Part Z represents the additional wheel positioned at right angle to the line OZ, ie appro: 23 degrees, with the rear axle CD. The straight line passing through the axle of this wheel, meets at a point 0 on the straight line passing through the front axles, at about 1ft away from the pivot point on L.S. This will be the new instantaneous centre, with respect to which the 3 wheels will make 3 concentric arcs when the vehicle turns in the forward or reverse direction towards left. The turning radius in this case is OZ which is much shorter and works out to approximately 2.28 metres. Zl and Z2 ve the positions of the additional wheel after fee vehicle turned through 90 degree towards left, in forward and reverse direction. In sheet no.4, figure 4 indicates the proposed steering system when the vehicle turns towards right Pot Z represents the additional wheel positioned at right angle to the 2 line OZ, ie appro: 23 degrees with the rear axle DC. The straight line passing through the axle of this wheel, meets at a point O on the straight line passing through the front axles at about 1 ft away from the pivot point on right side This will be the new instantaneous centre, with respect to which the 3 wheels will make 3 concentric arcs when die vehicle turns towards right. The turning radius in ttw case is OZ and works out to be the same ie 2.28 meters, as in the case of Figure 3. Zl is the position of the additional wheel after the vehicle turned through 90 degree towards right, in forward direction.. The vehicle can also turn through 90 degree towards right in reverse direction, with the same tuning radius. Figure 4 also indicates the latest 4 wheel steering system developed recently in Japan When the frost wheels steer to the right the rear wheels steer to the left, as the vehicle turns to right The instantaneous centre in this case will be 01. The right side 2 wheels will describe a common arc with 01B = Ol D as radius, and the left side 2 wheels will describe another common arc with Ol C = Ol A as radius. These two arcs which are concentric will have their instantaneous centre at Ol. In this case the turning radius will be C Ol which is equal to A Ol. Even if the inner wheels steer through 23 degrees the timing radius will work out to 3.65 meters: obviously quite larger than the 3 wheel system. Also in this system, since all the four wheels have to be steered, it is quite likely that the various complicated links in the steering mechanism can develop “play” which can disturb the instantaneous centre resulting in excessive tyre wear and can also lead to major accidents due to tyre skid on fast speed. The system is also expensive and is not popular any where in the world. In sheet no.5, Figure 5 shows how 2 additional wheels Z3 and Z4 can be used at the rear, instead of one. in the case of heavy vehicles. In this case 2 main hydraulic cylinders will be used for vertical movement of the 2 wheels, and 2 auxiliary cylinders will be used for steering the wheels. There also the turning radius remains as O Z4 as in the case of single wheel. Z5 and Z6 show die position of the two additional wheels after the vehicle turned through 90 degree towards left Figure 6 gives the Hydraulic circuit required for controlling the main cylinder for vertical movement and the auxiliary cylinder for steering. Part 1 is the oil reservoir. Part 2 is the gear pump operating at about 25Kg/cm square pressure. Part 3 is the direction 3 control valve in the auxiliary circuit Pail 4 is the auxiliary cylinder. Part 5 is the two way hydraulic valve in the auxiliary circuit Part 6 is the main cylinder. Part 7 is the two way hydraulic valve in the main circuit Part 8 is the pressure relief valve in the main circuit Part 9 is the direction control valve in the main circuit. The pump is driven from the engine. Normally the direction control valve 9 is kept with its delivery back to the reservoir. When this valve is actuated, the oil flow is diverted into the valve 7. Normally the oil flow is directed into the bottom of the main cylinder. When valve 7 is actuated the oil flow will be diverted to the top of the main cylinder and also to the bottom of the auxiliary cylinder. The steering wheel will now move down wards and lift the rear of the vehicle by about 1” from ground The vehicle can now make a sharp turn either to the extreme right or to the extreme left, depending on the position of valve 5. If necessary, any direction between extreme right and left can be chosen by operating valve 3. The drive for the pump can be taken through a D.C. clutch in which case valve 9 will be eliminated The system is intended basically for parking in the narrow parking bays where the conventional steering system will find it difficult to maneuver. The system will also be helpful to negotiate in narrow passages. The inclination of the steering wheel can be adjusted in such a way so that the instantaneous centre will fall exactly at the point where the front inner wheel contacts the ground, and there by the vehicle can turn exactly at right angle keeping the inner front wheel stationary However since this will increase the tyre wear, the instantaneous centre is kept at about 1 ft away from the front wheel contact point, for normal operation.

Documents:

0290-che-2006 abstract-duplicate.pdf

0290-che-2006 claims-duplicate.pdf

0290-che-2006 description (complete)-duplicate.pdf

0290-che-2006 drawings-duplicate.pdf

290-che-2006- form1.pdf

290-che-2006-abstract.pdf

290-che-2006-claim.pdf

290-che-2006-correspondence-others.pdf

290-che-2006-correspondence-po.pdf

290-che-2006-description(complete).pdf

290-che-2006-drawings.pdf

290-che-2006-form 9.pdf