fig1 is a side view of a steering system for a vehicle having an auxiliary steering device of the present invention . as shown in this drawing , the steering system includes a driven bevel gear 22 . gear 22 is fixed to a steering drive shaft 12 extending from a steering wheel 11 over a joint 13 such that the gear 22 is rotated along with the steering drive shaft 12 of the steering wheel 11 . the driven bevel gear 22 gears into a drive bevel gear 21 whose rotating shaft 23 is mounted to a side wall of a steering shaft column 14 . fig2 and 3 show an auxiliary steering device in accordance with a preferred embodiment of the present invention . as shown in the drawings , the outside surface of the drive bevel gear 21 is provided with an eccentric pin 24 which is eccentric from the rotating shaft 23 of the drive bevel gear 21 . an end of a connecting rod 26 is pivoted to the eccentric pin 24 of the drive bevel gear 21 . the other end of the connecting rod 26 is pivoted to a top end of a crank lever 29 using a pin 34 . the crank lever 29 makes a reciprocating movement around a rotating shaft 28 . therefore , the crank lever 29 and the connecting rod 26 of the auxiliary steering device of the invention form a crank mechanism by the up and down movement of pedal 38 . the above crank mechanism formed by the crank lever 29 and the connecting rod 26 converts reciprocation angular motion of the crank lever 29 into a rotating motion of the drive bevel gear 21 . in order to hinge the one end of the connecting rod 26 to the drive bevel gear 21 , it is preferred that the one end of the connecting rod 26 is provided with a boss 26a , and the eccentric pin 24 of the drive bevel gear 21 is fitted in the boss 26a with interposition of a bearing 25 , for achieving smoother power transmission . after fitting the eccentric pin 24 in the boss 26a , a snap ring 43 is tightly engaged with the pin 24 at the outside of the boss 26a so that sudden separation of the boss 26a from the pin 24 is prevented . in order to pivot the other end of the connecting rod 26 to the crank lever 29 , the top end of the crank lever 29 is provided with a pin 34 while the other end of the connecting rod 26 is provided with a boss 26b , and the pin 34 of the crank lever 29 is fitted in the boss 26b with interposition of a bearing 35 , for achieving smoother power transmission . after fitting the pin 34 in the boss 26b , a snap ring 44 is tightly engaged with the pin 34 at the outside of the boss 26b so that sudden separation of the boss 26b from the pin 34 is prevented . the end section of the arm 30 is provided with a slide hole for movably receiving one end of a lift lever 36 . the other end of the lift lever 36 is pivoted to the front section 38a of a steering pedal 38 using a pin 37 and a snap ring 45 . the diameter of the through hole of the arm 30 is larger than that of the lift lever 36 so that the lift lever 36 is somewhat playable in the through hole of the arm 30 . when the lift lever 36 is playable relative to the through hole of the arm 30 as described above , the lift lever 36 can be slid in and turned about the through hole of the arm 30 . in order to couple the lift lever 36 to the front section 38a of the steering pedal 38 in such a manner that the lever 36 generates a reciprocation angular motion in accordance with pedal operation , the front section 38a of the pedal 38 is provided with a triangular recess 39 as shown in fig5 . the other end of the lift lever 36 is pivoted to the front section 38a of the pedal 38 using the pin 37 in the inside corner of the triangular recess 39 . as the other end of the lift lever 36 is received in the triangular recess 39 and pivoted to the inside corner of the triangular recess 39 , the lever 36 is vertically movable with the steering pedal ; that is , not vertically movable relative to the recess 39 but horizontally rotatable about its pivot point in the triangular recess 39 of the pedal 38 . therefore , the lever 36 generates a vertical angular motion and a horizontal reciprocation angular motion in accordance with a pedal operation . the center portion of the steering pedal 38 is pivoted using a pivot shaft 40 . shaft 40 transversely extends in the center of the pedal 38 and pivoted to the bracket plate 15 , so that the front section 38a of the steering pedal 38 can be levered vertically about the center shaft 40 when working the pedal 38 . therefore , the steering pedal 38 generates the reciprocation angular motion through the lift lever 36 . the bottom surface of the steering pedal 38 is biased upward by a pair of bottom springs 41 and 42 . springs 41 and 42 are provided on the front and rear sections 38a and 38b of the bottom surface of the pedal 38 , respectively . with the bottom springs 41 and 42 , the front and rear sections 38a and 38b of the pedal 38 are elastically returned to their original positions when removing the foot from the pedal 38 after working the pedal 38 . when the pedal 38 is in the original position , the steering system lets the vehicle travel straight . and fig8 shows arrangement of the steering pedal 38 of the auxiliary steering device of invention relative to the other pedals ; that is , a clutch pedal 16 , a brake pedal 17 and an accelerator pedal 18 . in fig8 the reference numeral 19 denotes a speed change lever . in the second embodiment of the invention , in order to reduce the friction between the arm 30 and the lift lever 36 and to allow a smooth motion , the end section of the arm 30 is provided with a ball housing having a ball socket 31 for receiving a ball 32 therein as shown in fig4 and 5 . the ball 32 is provided with a slide hole 33 for slidable reception of the one end of the lift lever 36 . with the slidable insertion of the lift lever 36 in the slide hole 33 of the ball 32 , the ball 32 sufficiently absorbs any deviation generated when converting the reciprocation angular motion of the lift lever 36 into an angular motion of the arm 30 . when there is the ball and socket joint for pivoting the lift lever 36 to the arm 30 , it is not necessary to make the diameter of the slide hole 33 of the ball 32 be larger than that of the lift lever 36 . in the third embodiment of the invention , the joint between the other end of the connecting rod 26 and the top end of the crank lever 29 may be achieved by a ball and socket joint . in the ball and socket joint , the other end of the connecting rod 26 is formed into a ball , while the top end of the crank lever 29 is provided with a ball socket for receiving therein the ball of the connecting rod 26 . the ball and socket joint is more profitable than the above pin coupling because the ball and socket joint forms a spherical pair instead of turning pair . in the forth embodiment of the invention , the crank lever 29 is integrated with an arm 30 into a single body . that is , the arm 30 extends from the bottom section of the crank lever 29 at an angle there between so that the arm 30 and the lever 29 form an l - shaped lever body 27 , which is rotatable about the rotating shaft 28 . herein below , the operation of the steering system having the above auxiliary steering device will be described with reference to the accompanying drawings . the steering system of fig3 lets the vehicle travel straight . when the steering pedal 38 in the state is kept by fixing the pedal 38 using the foot , the bevel gears 21 and 22 gearing into each other and the steering wheel 11 are fixed to the straight traveling state , so that the vehicle keeps traveling straight even when the operator &# 39 ; s hands are free from the steering wheel 11 . fig6 shows the auxiliary steering device of invention when steering the wheels in order for turning the vehicle rightward . fig7 shows the auxiliary steering device when steering the wheels in order for turning the vehicle leftward . when the steering pedal 38 is worked so that the front section 38a of the pedal 38 is pushed down as shown at the arrow of fig6 the l - shaped lever body 27 is turned about the rotating shaft 28 counterclockwise due to leverage of the lift lever 36 . the counterclockwise turning motion of the lever body 27 about the shaft 28 is transmitted to the drive bevel gear 21 through the connecting rod 26 and thereby rotates the gear 21 clockwise . the clockwise rotating motion of the drive bevel gear 21 is transmitted to the steering drive shaft 12 through the driven bevel gear 22 gearing into the drive bevel gear 21 , thus to rotate the drive shaft 12 rightward and to turn the vehicle rightward . on the other hand , when the steering pedal 38 is worked so that the rear section 38b of the pedal 38 is pushed down as shown at the arrow of fig7 the lever body 27 is turned about the rotating shaft 28 clockwise due to leverage of the lift lever 36 . the clockwise turning motion of the lever body 27 about the shaft 28 is transmitted to the drive bevel gear 21 through the connecting rod 26 and thereby rotates the gear 21 counterclockwise . the counterclockwise rotating motion of the drive bevel gear 21 is transmitted to the steering drive shaft 12 through the driven bevel gear 22 , thus to rotate the drive shaft 12 leftward and to turn the vehicle leftward . when working the steering pedal 38 in order to turn the vehicle to either side , the operator naturally uses the left foot because the pedal 38 is positioned in the left side of the operator &# 39 ; s seat , as shown in fig8 . the above - mentioned steering operations using the foot - operated steering pedals 38 are effective only when the eccentric pin 24 of the drive bevel gear 21 is positioned within the range including the points &# 34 ; lt &# 34 ;, &# 34 ; lo &# 34 ; and &# 34 ; rt &# 34 ; of fig6 . however when the eccentric pin 24 of the drive bevel gear 21 is positioned within the range including the points &# 34 ; lt &# 34 ;, &# 34 ; hi &# 34 ; and &# 34 ; rt &# 34 ; of fig6 the above - mentioned steering operations using the foot - operated steering pedals 38 will be reversed . in the steering system , the eccentric pin 24 of the drive bevel gear 21 may be positioned in either of the four points &# 34 ; lt &# 34 ;, &# 34 ; lo &# 34 ;, &# 34 ; rt &# 34 ; and &# 34 ; hi &# 34 ; when controlling the steering system by the steering wheel 11 . however , the control for the steering system by the steering pedal 38 is only effective within the range of ± 90 leftward and rightward turning angle of the drive bevel gear 21 . when the vehicle travels straight , the eccentric pin 24 of the drive bevel gear 21 is always positioned on the point &# 34 ; lo &# 34 ; due to restoring force of the steering wheel 11 . in addition , the steering system is sufficiently controlled by ± 20 leftward and rightward turning angle of the drive bevel gear 21 when the vehicle travels on a straight road such as a high way . therefore , there is no problem in controlling the steering system by the foot - operated steering pedal 38 of the auxiliary steering device of the invention . as shown in fig8 the steering pedal 38 is positioned in the left side of the operator &# 39 ; s seat so that the steering system having the auxiliary steering device of this invention can be naturally controlled by the foot - operated steering pedal 38 without handling the steering wheel 11 . this facilitates the steering operation for the vehicle . in the present invention , the steering pedal 38 preferably has a size similar to that of another pedal , such as the brake pedal 17 or the accelerator pedal 18 . the inclination angle of the steering pedal 38 in the straight traveling state is equal to that of the bracket plate 15 . in addition , it is preferred to make the front section 38a of the steering pedal 38 be vertically reciprocated within ± 4 cm range . the size of the lever body 27 , the length of the arm 30 and the sizes of the bevel gears 21 and 22 may be changed in accordance with conditions of a vehicle to which the auxiliary steering device of this invention is installed . however , it is preferred to let the diameter of the driven bevel gear 22 be less than that of the steering wheel 11 so that the hand - operated steering motion is not disturbed by the foot - operated steering motion when makes controlling the steering system by both . with the above auxiliary steering device , the steering system can be desirably controlled by a foot particularly when the vehicle travels on a straight road such as a highway having good driving conditions . that is , the steering system with the above auxiliary steering device can be controlled by either of an exclusive hand operation , an exclusive foot operation or a hand and foot operation . therefore , the steering system can be controlled by either of the above three operation types in accordance with road conditions and operator &# 39 ; s conditions . when the steering system is controlled by the foot - operated steering pedal , the operator &# 39 ; s hands are free from the steering operation so that the operator in operation of the vehicle may use his or her hands to operate a portable phone , handle the dashboard or the stereo system , enjoy something to eat or drink , or smoke without the danger of having a traffic accident . of course , when the operator of the vehicle feels sleepy , the operator may exercise , such as stretching the body with raised hands , while controlling the steering system by the foot - operated steering pedal . the steering pedal is positioned in the left side of the operator &# 39 ; s seat so that the operator naturally uses the left foot when working the steering pedal for controlling the steering system by the pedal . the auxiliary steering device has a simple construction so that the device is free from a problem caused by operational trouble and cost . the auxiliary steering device may be simply used with typical vehicles without changing the constructions of the vehicles . the steering system of the invention can be controlled by either the hands or the foot so that the operator may use the hand sense as well as the foot sense during operation of the vehicle and this prevents possible traffic accident . furthermore , the steering pedal of the auxiliary steering device is connected to the steering handle through a mechanical mechanism so that the operators may appropriately work the pedal without special exercise for operating the pedal . when the vehicle travels on a rapidly curved road , the normal steering state of the steering system controlled by the steering wheel is returned by simple separating of the foot from the steering pedal . hence , there is no problem in use of the auxiliary steering device in conventional steering systems . as described above , the present invention provides an auxiliary steering device for vehicle including a mechanism for converting a reciprocation angular motion of a steering pedal into a rotating motion of a steering drive shaft of the steering system , so that the auxiliary steering system lets the steering system be controlled by either the hand - operated steering wheel or the foot - operated steering pedal . although the preferred embodiments of the present invention have been disclosed for illustrative purposes , those skilled in the art will appreciate that various modifications , additions and substitutions are possible , without departing from the scope and spirit of the invention as disclosed in the accompanying claims .