Background Art In line with the development of updated technology, the number of automotive vehicles have been significantly increased, and roads of main cities of the world are bumper to bumper. Thus, securing parlcing lots becomes the serious problem. As one way of securing parking lots, parlcing buildings, tower parlcing, etc. have been constructed, which are insufficient to solve parldng difficulties in downtown areas.

As another way of solving the parking difficulties, a directional control system for an automotive vehicle was proposed in order to reduce a unit area for parking one vehicle and park much more automotive vehicles.

Japanese Patent Publication No. Sho 42-21689 (published on October 25, 1967), Japanese Patent Publication No. Sho 49-30286 (published on December 6,1969), Korean Patent Publication No. 88-562 (published on April 15,1988) disclose directional control systems which minimize a radius of changed vehicle

in direction or elevate a vehicle body from the ground for direction change. Such systems have problems of changing the vehicle structure and further attaching a hydraulic equipment and an extra frame for supporting the equipment, and they are not put to practical use because of a change in the outer design and safety problems.

As disclosed in Korean Patent Publication No. 95-877 (published on February 3,1995), a directional control system A includes a cylinder 11 having a fixing means 10 attached to a support 3 via bolts; a forward/reverse motor 12 for elevation having an integrally formed reduction device 12a and fixedly mounted on one side of cylinder 11; and a forward/reverse motor 13 for right/left rotation having a reduction device 13a and mounted on the other side of cylinder 11.

A piston 14 is formed to reciprocate in cylinder 11, and a lead screw 15 turning left and right on its axis is joined to a female screw 14a formed in the middle of piston 14. Lead screw 15, joined to female screw 14a of piston 14, has a lower end fonning a free end when it is inserted into female screw 14a of piston 14, and an upper end which passes through the upper portion of cylinder 11 and on which an interloclcing sprocket 16 is mounted.

Interloclcing sproclcet 16 is connected to a drive sproclcet 12c, attached to an output shaft 12b protruding from the upper portion of forward/reverse motor 12, via a chain 17, thus transmitting forward/reverse rotating output of forward/reverse motor 12 to lead screw 15. Forward/reverse motor 13, mounted on the other side of cylinder 11 of directional control system A, is attached to a protruding end of piston 14 where a thrust bearing 18a is installed to move up and down as piston 14 reciprocates.

Rotary sprocket 20 is integrally mounted on a lower support means 19b while an upper support means 19a is fixed to a lower end of the protruding end of piston 14. Thrust bearing 18a is interposed between upper support means 19a and lower support means 19b, and a loclcing bolt 21's tip is assembled to piston 14's protruding end for isolating upper support 19a from rotary sproclcet 20 mounted on lower support means 19b and supporting vertical load. A hinge projection that is formed on one edge of lower support means 19b is joined to another hinge projection formed on one edge of braclcet 23 of a directional control guidance wheel 22 by a hinge assembly 24, and when braclcet 23 is erected, its upper part comes in close contact with the lower portion of lower support means 19b. On the contrary, when braclcet 23 is folded, its folding angle malces a right angle. Rotary sproclcet 20, mounted on lower support means 19b, is connected to rotary drive sprocket 13c attached to output shaft 13b of reduction device 13a of forward/reverse motor 13 via chain 17, and transmits an output of forward/reverse motor 13 to lower support means 19b and bracket 22 mounted on its lower portion. Directional control guidance wheel 22 selectively rotates left or right, and after rotation, it can return to its original position.

An automotive vehicle with the conventional directional control system, utilizing the power source and the general driving system of the above conventional front-drive automotive vehicle, must have an extra support. In addition, the directional control is available only when directional control guidance wheel 22 contacts the ground, and directional control guidance wheel 22 does not rotate easily. That is why the conventional directional control system is not practically used.

Summary of the Invention Accordingly, the present invention is directed to a directional control system for an automotive vehicle that substantially obviates one or more of the problems due to limitations and disadvantages of the conventional art.

It is an objective of the present invention to provide a directional control system for an automotive vehicle which is provided to each of suspensions of rear wheels of a front-drive vehicle and facilitates a change in the direction of the vehicle on a narrow road where the vehicle's direction is not easily changed just by turning a steering wheel.

It is another objective of the present invention to provide a directional control system for an automotive vehicle which has an elevating means which is foldable during drive not to hinder the vehicle from going in a particular direction.

To achieve the above objects, the present invention discloses a directional control system for an automotive vehicle.

According to the inventive directional control system, a reduction means, mounted on a directional control system body having an upper part attached to suspensions for an automotive vehicle, moves up and down elevating means joined to a cylinder while a lead screw rotates forward and reverse by using a rotating force transmitted from a first motor, and a loclcer opening part is mounted on a lower end of the body and has a straight surface on its bottom and an integrally formed loclcing pin release with slants on its lower portion. A lock guide is formed to have an integrally formed projection on its lower end so a loclcing state by a loclcer is released at a point where the cylinder is elevated. A bolt of an elevating bar is elevated by the rotation of a nut to which a rotating force from a second

motor is transmitted via a belt, and an operating bar, coupled to the elevating bar via a hinge, 90° rotates a folding part about a rotating shaft while the folding part is inserted into a circular hole.

The locker is mounted on the cylinder's lower end and is loclced in a loclcing groove of the folding part rotating about a shaft, and a fixing portion of the loclcer having a slant on its upper portion and releasing the loclcing state of the folding part has loclcing pins on its both sides to be pushed by slants of the loclcing pin release. A rotating wheel has an integrally formed bolt on a lower support of the folding part into which a nut on an end of the fixing portion of the rotating wheel is fastened, and a worm formed on an outer surface of the nut to rotate forward and reverse by a worm gear to which a rotating force of a third motor is transmitted through gears.

Additional advantages, objects and other features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary slcill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.

Brief Description of the Drawings FIG. 1 is a schematic view of the construction of a conventional directional control system for an automotive vehicle; FIG. 2 is a rear view of a directional control system of the present invention installed on an automotive vehicle;

FIG. 3 is a sectional view of the overall construction of the inventive directional control system; FIG. 4 is a schematic view of a folding part of the inventive directional control system being folded; FIG. 5 schematically depicts an elevating part of the inventive directional control system being moved up; FIG. 6 schematically depicts the elevating part of the inventive directional control system being moved down; FIG. 7 schematically depicts a released state of a loclcer of the inventive directional control system; and FIG. 8 is a block diagram of the present invention.

Best Mode for carrying Out the Invention The preferred embodiment of the present invention will become apparent from a study of the following detailed description, when viewed in light of the accompanying drawings.

FIG. 2 depicts the present invention provided to an automotive vehicle.

Fixing means 44 and 44a are secured to suspensions 43 and 43a rear wheels 42 and 42a of a vehicle body 41 by bolts, and directional control system body 45 is securely attached to fixing means 44 and 44a.

FIGS. 3 to 7 depict the construction of a directional control system in accordance with the present invention.

A reduction means 51, consisting of plural gears and positioned on directional control system body 45 attached to each of suspensions 43 and 43a of

vehicle body 41, elevates a lifter 61 joined to a cylinder 54 by a rotating force transmitted from first motor 52 while a lead screw 53 is rotating forward and reverse in cylinder 54.

On the lower end of body 45 is formed a loclcer opening part 55 having an integrally formed loclcing pin release 57 with slants 58 and 58a, and a straight surface 56 formed on its bottom, and a lock guide 59 having an integrally formed projection 59a. Loclcing by a loclcer 68 is released at a point where cylinder 54 is moved up so folding part 62 of lifter 61 by a second motor 64 rotates about a rotating shaft 63. A bolt 67a of elevating bar 67 is elevated by the rotating force of second motor 64 transmitted through a belt 65, and an operating bar 67c, coupled to elevating bar 67 via a hinge 67b, rotates folding part 62 about rotating shaft 63 while operating bar 67c is inserted into a circular hole 62a of folding part 62. Loclcer 68 contacting projection 59a of lock guide 59 and positioned on lower end of cylinder 54 rotates about a shaft 68a and is loclced in a loclcing groove 62b of folding part 62 to maintain the vertical state of folding 62.

Loclcing pins 69a and 69b for preventing rotation of loclcer 68 about shaft 68a are each provided to both sides of a fixing portion 69 of loclcer 68 which has an upper portion formed of slant 68b and rotates about shaft 68a when it contacts straight surface 56 and releases folding part 62 being loclced. Locker 68 is pushed to the inside by lower slants 58 and 58a of loclcing pin release 57 to be rotatable about shaft 68a.

A bolt 70a is fixed to lower support 70 of folding part 62, to which a nut 73, provided to an end of a rotating wheel 71's fixing part 72, is joined by a screw.

A worm 74 is integrally formed on an outer surface of nut 73, and rotates forward

and reverse by a worm gear 78 to which the rotating force of a third motor 75 is transmitted.

FIG. 8 is a block diagram of the present invention.

When a driver turns on a left rotation lcey 80, a central rotation lcey 81, or right rotation key 82 to move his or her automotive vehicle to the right, left or center, a main controller 83 which is supplied with power from the outside controls a first motor driving part 84 driving first motor 52 to lift the vehicle body. Main controller 83 controls first motor driving part 84 driving first motor 52 to fold or unfold folding of lifter 61, and controls a third motor driving part 86 driving third motor 75, thus turning rotating wheel 71 left, right or center while rotation sensors 87,88 and 89 correctly sense the rotating state.

According to the inventive directional control system when a driver either parlcs a front-drive vehicle turning it right or left in a small space or moves it to a road from the parlcing lot, as he turns on left rotation lcey 80 or right rotation lcey 82, folding part 62 of lifter 61 is being folded, and it is rightangled by second motor 64. After rotating wheel 71 turns to a desired direction by third motor 75, first motor 52 moves lifter 61 down along with cylinder 54 to lift the vehicle body's rear part in such a manner that the vehicle direction can be abruptly changed.

The following description relates to a case when the vehicle turns left for parlcing.

As the driver turns on left rotation lcey 80, main controller 83 controls a second motor driving part 85 to drive second motor 64. A nut 66, receiving the rotating force of second motor 64 through belt 65, elevates bolt 67a of elevating

bar 67.

As elevating bar 67 elevates, operating bar 67c, integrally coupled with bar 67 via hinge 67b, elevates to be vertical, and folding part 62, inserted into circular hole 62a and folded by 90°, is turned by 90° and unfolded vertically.

When folding part 62 is vertical, main controller 83 outputs a control signal to third motor driving part 86 driving third motor 75 to rotate third motor 75 forward, and worm gear 78 rotates forward, thus turning worm 74 left.

As nut 73 having a worm 74 formed on its outer surface turns forward, fixing part 72 of rotating wheel 71 with nut 73 joined to bolt 70a installed on the lower end of cylinder 54.

If rotation sensors 87,88 and 89 installed on lower support 70 of folding part 62, determine that rotating wheel 71 rotates left, main controller 83 stops third motor 75. As folding part 62 is unfolded and rotating wheel 71 turns to a desired direction, main controller 83 outputs a control signal to first motor driving part 84 to rotate first motor 52 of directional control system body 45 forward.

While lead screw 53 is rotating forward in cylinder 54 by the rotating force from reduction means 51, cylinder 54 is moved down, and lifter 61 is also moved down.

As lifter 61 joined to the lower end of cylinder 54 descends and rotating wheel 71 touches the ground, automotive vehicle 41 is elevated.

The moment cylinder 54 is completely moved down, loclcer 68, provided to the lower end of cylinder 54, contacts projection 59a of lock guide 59 and rotates about shaft 68a, and is then loclced in loclcing groove 62b of folding part 62, thus stably maintaining the vertical state of folding part 62.

As the rear part of vehicle body 41 is being lifted while only rotating wheel

71 touches the ground, front-drive vehicle 41 turns left abruptly to be easily parked or moved to a road by the use of front wheels and rotating wheel 71.

When the driver turns on central rotation lcey 81 after moving the vehicle, main controller 83 outputs a control signal to first motor driving part 84 to rotate first motor 52 reverse. While lead screw 53 rotates reverse in cylinder 54 by the rotating force transmitted via reduction means 51, cylinder 54 is elevated to move lifter 61.

When lifter 61 is being elevated, locldng pins 69a and 69b prevent the rotation of loclcer 68 that is coupled to fixing portion 69 to be rotatable about shaft 68a and having slant 68b on its upper portion, and it is elevated in the unlocked state.

When locldng pins 69a and 69b touch slants 58 and 58a of locldng pin release 57, provided to the lower end of directional control system body 45, to become wider to both sides, loclcer 68 can rotate about shaft 68a.

When straight surface 56 provided to the bottom of loclcer opening part 55 contacts slant 68b formed on loclcer 68, loclcer 68 rotates about shaft 68a to be released while loclcing groove 62a of folding part 62 is in lock so that folding part 62 can rotate.

As lifter 61 is completely elevated, main controller 83 outputs a control signal to third motor driving part 86 driving third motor 75 so third motor 75 rotates reverse and worm gear 78 integrally formed with the shaft rotates reverse, thus turning worm 74 that is in mesh with worm gear 78 right.

The reverse rotation of nut 73 having worm 74 on its outer surface rotates fixing part 72 of rotating wheel 71 with bolt 70a provided to the lower end of

cylinder 54 and joined to nut 73. When rotation sensors 87,88 and 89, mounted on lower support 70 of folding part 62, determine that rotating wheel 71 turns to the center, main controller 83 stops the rotation of third motor 75.

Therefore, as lifter 61 is elevated to release loclcer 68 and rotating wheel 71 turns to the center, main controller 83 controls second motor driving part 85 to drive second motor 64, and nut 66 receiving the rotating force of second motor 64 through belt 65 moves bolt 67a of elevating bar 67 down.

As elevating bar 67 is moved down, operating bar 67c joined thereto via hinge 67b is liable to move down, and since lifter 61 is elevated, hinge 67b is curved, and operating bar 67c rotates folding part 62, inserted into circular hole 62a, by 90° so that folding part 62 rotates about rotating shaft 63 by 90° to be folded. Therefore, the automotive vehicle is capable of going in a particular direction without the inventive directional control system's touching the ground because folding part 62 of lifter 61 is being folded.

According to the directional control system of the present invention, the directional control system joined to the suspensions for an automotive vehicle elevates the cylinder and elevating means to lift the vehicle. At the time of lifting the cylinder, the loclcer is released by the loclcer opening part with the loclcing pin release and the lock guide, and the bolt of the elevating bar is elevated so that the operating bar joined to the elevating bar via the hinge folds the folding part. The locldng pins prevents the rotation of the loclcer, and the rotating wheel with the bolt of the lower support joined to the nut rotates forward and reverse by the worm gear to which the rotating force of the third motor is transmitted. The inventive directional control system can be simply and easily provided to each of

the suspensions for the rear wheels of the front-drive vehicle via the fixing means.

Since the present invention easily changes the direction of the vehicle with much rotating force, and the folding part is folded when driving the vehicle not to cause a damage thereto, it can be in use with safety.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those sldlled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as recited in the accompanying claims.