US3850259A - Walking vehicle - Google Patents

Abstract

A walking vehicle is provided which comprises a main body having four corners, four leg mechanisms, one connected to each of the corners, a driving means for driving the leg mechanisms and a control means for controlling the driving of the leg mechanisms.

Description

United States Patent 1191 Ikeda et al. Nov. 26, 1974 WALKING VEHICLE 2,918,738 12 1959 Barr 180 8 E x 1 1 Kiichi Ikeda; Kimam Taguchi; 5333333 1371321 #2253 13?" 11111238111121 Taketoshl Nolaki; Shuntets" 3,134,453 5 1964 Cirami 180 8 E Mats m a of y ap 3,135,345 6/1964 Scruggs 180/8 E [73] Assignee: Agency of lndustrial Science &

Technology, kyo, Japan FOREIGN PATENTS OR APPLICATIONS 423,063 12 1925 Germany 180/8 E [22] Flledl 1973 627,988 11/1961 Italy 180 8 E [21] Appl. No.: 346,321

' Primary Examiner-Leo Friaglia 30 Foreign Application Priority Data Attorney Agent Firm-Kurt Kelman May 30, 1972 Japan 753731 A 27, 1972 J 47-50043 pr 57 ABSTRACT A walking Vehicle is provided which Comprises a main [58] i 280/1 181 body having four corners, four leg mechanisms, one 0 care connected to each of the corners, a driving means for driving the leg mechanisms and a control means for [56] References C'ted controlling the driving of the leg mechanisms.

UNITED STATES PATENTS 1,511,928 10 1924 Zboril 180 8 E 4 Claims, 36 Drawing Figures WALKING VEHICLE BACKGROUND OF THE INVENTION The present invention relates to a control system for a walking vehicle provided with four legs.

A walking vehicle with four legs has the following advantages over conventional vehicles using wheels, such as automobiles, rail-way cars, etc.:

It is possible to move along rough surfaces such as unpaved roads and rocky areas, etc., or steep surfaces such as mountain passages and slopes, etc.

It is also possible to move along surfaces such as marshes, deserts and icy and snowy lands, etc, whose physical properties such as supporting capacity, firmness and coefficient of friction, etc., are unstable.

Changes in direction and velocity can be easily performed.

Since, as above mentioned, the four-legged walking vehicle has advantages over the conventional vehicle using wheels in that the walking vehicle can move on and along all types of surfaces, it is capable of being utilized widely not only in the exploitation of the bottom of sea and the surfaces of heavenly bodies but also in rescue operations, high altitude and fire-extinguishing work, and other jobs too difficult for men to do directly.

Despite the above-mentioned advantages of the fourlegged walking vehicle, such vehicles have not come into generally use because of the complex construction thereof.

An object of the present invention is to provide a four-legged walking vehicle which has a simple construction and is able to perform various walking functions.

SUMMARY OF THE INVENTION In order to achieve the above mentioned object of the present invention, the four-legged walking vehicle according to the present invention is provided with a means for appropriately controlling the operation of the leg mechanisms secured movably to the corners of the main body of the walking vehicle so that the four legs are driven appropriately to walk the vehicle in complex patterns including forward walking, reverse walking and turn about.

Other objects and features of the present invention will become apparent from reading the detailed explanations of embodiments of the present invention with reference to the drawings, in which:

FIG. I is a side view of an embodiment of a fourlegged walking vehicle according to the present invention;

FIG. 2 is a bottom view of the embodiment shown in FIG. 1;

FIG. 3 is a side view of a portion of the embodiment in FIG. 1, showing a walking cycle comprising walking and return strokes of one leg mechanism;

FIGS. 4(a) to 4(e) are explanatory illustrations for showing one walking cycle with attitude variation when the four legs are driven out of phase from each other by 90;

FIGS. 5(a) to 5(d) are explanatory illustrations showing one walking cycle when the front leg mechanisms and the rear leg mechanisms are separately driven in phase while a phase difference of 180 exists between the front legs and the rear legs;

FIGS. 6(a) to 6(d) are explanatory illustrations showing one walking cycle when the front and rear legs on either side are in phase while the legs on one side are 180 out of phase from those on the other side;

FIGS. 7(a) to 7(d) show the attitude variation during one walking cycle according to FIGS. 6(a) to 6(a);

FIG. 8 shows the walking mode of the main body as it turns to the left;

FIGS. 9(a) to 9(d) show one walking cycle in the mode shown in FIG. 8;

FIG. 10 is a side view of another leg mechanism;

FIGS. 11(a) to 11(e) show the legs in the state of quick return;

FIG. 12 is a schematic illustration of one mechanism for providing quick return stroke;

FIG. 13 is another example of a mechanism for providing quick return stroke;

FIG. 14 is another example of a leg mechanism;

FIG. 15 is another example of a leg mechanism which is a modification of that shown in FIG. 10 and FIG. 16 is a further example of a leg mechanism.

Generally, the present four-legged walking vehicle comprises a main body, four leg mechanisms, one provided at each of four corners of the main body, for supporting and driving the main body, a driving means for driving the leg mechanisms and a control means for controlling the motions of the respective leg mechanisms.

FIGS. I and 2 show an embodiment of the walking vehicle, in which each of the legs 2 connected rotatably to the corners of the rectangular main body I comprises upper two linkages 4 each of which has an elongated slot 11 and lower two linkages 5. The upper linkages are connected rotatably at their upper ends to the main body I and are crossed to form a generally X- shape. The lower linkages 5 are rotatably connected with each other at their lower ends and are adopted to contact with a road surface. The upper end of each lower linkage 5 is connected rotatably to the lower end of an upper linkage 4.

At the center of the main body, there is mounted a motor 3 for driving the respective leg mechanisms so that the center of gravity center of the motor coincides with the center of gravity of the main body. The rotational output of the motor is transmitted equally to the front legs and the rear legs through a driving shaft 7 for the front legs and a driving shaft 8 for the rear legs and through suitable gear mechanisms 6. At the opposite ends of the respective driving shafts 7 and 8, are fixed arms 9 provided with outwardly extending eccentric pins 10. Each of the pins 10 is inserted into the slots 11 of the upper linkages 4 to form the crossing center of the two linkages 4, so that, upon the rotation of the driving shaft 7 (or 8), the pin 10 provided on the associated arm 9 is rotated around the shaft and reciprocates the two linkages 4 through their slots 11 to thereby alternatively expand and contract the lower end connection of the lower linkages 5 through a locus such as shown in FIG. 3. That is, assume that the main body 1 is fixed and the eccentric pin is rotated. When the pin is at the uppermost position, the associated leg is in the contracted state and the lower end connection of the lower linkages is at position A. If the pin is then rotated through an angle of the end connection is transferred to position B. When the pin is rotated through another 90, the leg is fully expanded and the connection reaches position C. When the pin is further rotated by 90, the position of the connection is moved to position D. In this manner, the lower end connection of the leg mechanism is expanded and contracted by the revolution of the arm 9 to complete one walking cycle for the leg.

The main body 1 can be made to perform various walking functions by changing the phase relationships between the legs.

Firstly, it is assumed that the positions of the eccentric pins 10 associated with the opposite ends of the driving shaft 7 and of the pins 10 associated with the driving shaft 8 are out of phase by 180 and are fixed so that the front left leg I and the rear right leg IV are in phase and also the front right leg II and the rear left leg III are in phase. Thus, the eccentric pins at diagonal opposite positions of the main body are in phase. FIGS. 4(a) 4(0) show the walking mode of the main body 1 due to the motions of the respective lower end connections of the legs. In the same figure, the symbol@ represents a leg whose end connection is in contact with the ground, symbol C shows a leg whose end connection is lifted above the ground, the arrows show the direction of motion of the legs, symbols A, B, C and D show the positions of the end connections of the legs in terms of the locus shown in FIG 3 and G is the position of the center of gravity of the total weight.

It is assumed that firstly all of the legs are in contact with the ground as in FIG. 4(a) and walking is started from this state. In this state, the front left leg I and rear right leg IV are at position D and the front right leg II and the rear left leg III are at position B, so that the attitude of the main body is maintained substantially horizontal by these four legs.

When the respective legs start to move in the arrow directions upon the rotation of the motor 3, legs I and IV are moved forwardly as their lengths expand and, since the G of the whole falls slightly off an imaginary line drawn between the legs [I and III (See FIGI 4(b)), the legs II, III and IV are grounded and support the weight of the main body. However, the major part of the total weight is supported by the legs 11 and III. Accordingly, since the friction between the ground surface and these two legs II and III which support the substantial part of the weight becomes larger than that between the surface and the leg IV bearing a relatively small weight, the end connection of the legs II and III become fulcrums which do not move with respect to the surface but cause the main body itself to move, while the leg IV slips along the surface, resulting in the movement of the main body in the direction opposite to the moving directions of the legs II and III. That is, the main body moves forward.

Since the legs II and III continue to expand until the end connections thereof reach the midway point of their strokes, i.e., reach the position D on the locus in FIG. 3 and the legs I and IV continue to contract until their end connections reach the position A, the main body is raised at the legs II and III and lowered at the leg IV, resulting in an inclination of the main body such that the leg 1 is lifted considerably from the ground surface as shown in FIG. 4(c).

Although the main body continues its forward movement even after reaching the state shown in FIG. 4(0), the leg IV will be lifted from the ground surface because the diagonal line drawn between the legs II and III is shifted behind G and the leg I is put in contact with the surface through an intennediate transition state in which the main body is supported by two legs, as shown in FIG. 4(c). Accordingly the body is supported by the legs I, II and III. In the last state, the attitude of the body is remarkably changed to one wherein the front left portion thereof is lowered.

Since, after intermediate stroke position of the legs shown in FIG. 4(0), the contracted legs I and IV begin to expand and the expanded legs II and III to contract, the tilted main body begins to recover its horizontal attitude. Since, even in this state, the substantial part of the total weight is still supported by the legs II and III, the friction between them and the surface are still larger than that between the surface and the leg I. Therefore the main body continues its forward movement with the legs II and III as fulcrums while the leg I slips along the surface. (See FIG. 4(d)) When the respective legs continue to move and reach position B or D, the lengths of the respective legs become the same and the weight is equally supported by the four legs so that the horizontal attitude of the body is recovered. (FIG. 4(e)) Thereafter the main body returns from the state shown in FIG. 4(e) to the initial state shown in FIG. 4(a), through a sequence similar to the sequence from FIG. 4(a) to 4(e) but with the moving modes of the right and left legs reversed, completing a full walking cycle.

In this manner, by making the two legs on either side out of phase leg and the diagonally opposite legs in phase, the main body can be made to move forward, alternatively rocking with the diagonal lines as axes.

FIGS. 5(a) to 5(b) show the movement of the main body in the case where the pair of front legs I and II are in phase and the pair of rear legs III and IV are also in phase but the phase of the front legs differs from the phase of the rear legs by 180. In this case, if the frictional forces of the end connections of the respective legs with respect to the ground surface are substantially the same, all end connections of the four legs slip with respect to the surface and thus the main body does not move forward but swings at a fixed position. However, since actually there may be differences in friction of force with respect to the surface between the ends of the front legs and the rear legs due to the respective motions of the legs and the displacements of the ends thereof, the main body can move forwardly. When the front leg I is in the most extended condition, the rear leg III is in the most contracted state. (See FIG. 5(a)) Since the position of the center of gravity G of the main body in this state is shifted slightly to the rear leg side, the contact point between the rear legs and the surface is not shifted even when the motion of the front and rear legs is commenced, so that the front legs slip along the surface and the main body advances as shown in FIG. 5(b). When the motion of the legs further continues and the main body begins to tilt forward, the position of G is shifted forward to the front leg side and the weight supported by the front legs increases while that supported by the rear legs decreases. Accordingly the friction forces of the front legs become larger and the rear legs slip, resulting in the forward movement of the main body through the state in FIG. 5(0) to the state shown in FIG. 5(d). Thereafter, the main body takes the attitude shown in FIG. 5(a) again with the front legs slipping and repeats the same cycles, resulting in a con tinuous walking movement.

In this manner, by making the front legs and the rear legs in phase respectively and making the front legs out of phase with respect to the rear legs by 71', the main body can advance while tilting to and fro.

FIGS. 6(a) to 6(d) show a case where the front and the rear left legs I and III and the front and rear right legs II and IV are in phase, respectively, and the left leg or legs are out of phase with respect to the right leg or legs by 180. In this case, if the respective legs have substantially the same friction with respect to the ground surface, the main body will merely slip and cannot advance. However, since G is shifted to and fro with the extending and contracting motions thereof, the main body can advance accordingly. FIG. 6 shows the positions of the leg points in the various states and FIG. 7 shows the attitudes of the main body corresponding to such positions of the leg points.

As shown in these figures, when the left legs I and III are in the most extended state and the right legs II and IV are in the most contracted state, G is closer to the right leg side. (FIGS. 6(a) and 7(a)) Accordingly the friction of the right legs becomes larger than that of the left legs and thus, even when the respective legs move, the contact points between the right legs and the ground surface do not shift and the left legs slip over the surface, resulting in the forward movement of the main body as shown in FIG. 6(b). Upon further motion of the legs, the left legs are contracted, tilting the main body leftwardly and thus shifting G to the left leg side (FIGS. 6(0) and 7(a)). Accordingly, the friction force of the left legs increases and consequently, even when the respective legs further move, the contact points of the left legs are not shifted and the right legs slip with respect to the surface, resulting in a further advancement of the main body as shown in FIG. 6(d). The main body then recovers the initial state shown in FIG. 6(a) upon the slipping of the left legs thereof and thus repeats its advancement in the same manner.

In this way, by making the left side and right side legs in phase, respectively, and making the left out of phase with the right by 180, the main body can move forwardly, alternately tilting to the right and left.

The description given above has been made for linear advancement of the main body. In any of the above cases, the walking efficiency is best when the phase difference is 180. However, the. main body can walk even when the phase difference is slightly varied from 180. In this case, however, the walking efficiency will be lowered slightly.

Now, non-linear motion of the main body will be described with reference to FIG. 8. That is, the turning mode will be explained.

As in the cases previously mentioned, when a pair of legs positioned diagonally which support the substantial part of the weight are in phase, the main body moves linearly. However, when the strokes of such two legs aremade different from each other during any time interval within their strokes, the main body can move non-linearly, that is, it can turn.

As shown in FIG. 8, assuming that the end connections of the two legs II and III are at positions Y and W, respectively, at a time t and the two legs make different strokes in direction and velocity so that these legs reach positions F and E, respectively, at a time At after the time t, the main body will move in the direction opposite to the arrows, resulting in a leftward turning by an angle 0.

During this turning movement, since the friction of the one of the two fulcrum legs II and III which supports the larger part of the weight becomes largest, the end connection of this leg will not be shifted relative to the surface and thus the other fulcrum leg will move with respect to the surface.

Accordingly, if the weight supported by the leg III at the position W is larger than that supported by the leg II at the position Y, the main body will be moved to a position defined by the leg positions W, X, Y and Z, while the leg II which was initially at the position Y slips on the surface and reaches the position F. As a result, the main body turns to the left, while moving slightly backward. On the other hand, although there is always one leg other than the fulcrum legs which is in return stroke and in contact with the surface, the friction thereof with respect to the surface is relatively small and accordingly the effect of such small friction can be ignored.

In such movement of the main body, the turning angle 6 0f the main body can be expressed as follows:

when

0 4% I 0, left turn,

6 be 0 right turn 9 #0 0 linear movement The traveling distance I of the main body can be expressed as follow:

As described above, in order to make the movement of the walking Vehicle non-linear, the strokes of the two fulcrum legs should be made different from each other for a suitable time interval of their walking and return strokes so that the vehicle turns or snakes because of the difference of the strokes. Changing the stroke or making the strokes different can be performed by varying the vertical position of the driving shaft 7 (or 8) in FIG. I or by changing the mounting position of the upper linkage thereof with respect to the body.

As a concrete example of the above described moving mode, an embodiment is shown in FIG. 9 in which such non-linear movement is achieved by displacing the phase of one leg from the phases of the remaining three legs.

In FIG. 9, legs I, III and IV are made in phase and only the leg [I is out of phase by with the other three legs (FIG. 9(a)). Since the extensions of the strokes of the legs II and III which are fulcrum legs are the same but in opposite directions, the vehicle moves backward slightly while turning left (FIG. 9b)). At this time, the front right leg II extended and the remaining legs are contracted. With further motion of the legs, the vehicle turns to the left and the attitude thereof becomes horizontal (FIG. 9(c)). Thereafter, the fulcrums are transferred to the legs I and IV and the vehicle moves straight because the moving directions and the strokes of the legs I and IV are the same, respectively (see FIG. 9(d)).

In the embodiments heretofore described, the phase of one or two legs is made different from other legs by 180.

Another example will now be described, in which, by making the respective legs different in phase or position from each other by a suitable angle, the main body can reach a destination while making complex movement. As a method of regulating the respective phases, it is possible to set them at any desirable position by providing an electro-magnetic clutch between the driving shaft 7 (or 8) and the associated arm 9 and applying an electrical signal to the clutch.

In the previous embodiments, although each of the legs mounted on the four corners of the main body 1 comprises two crossed upper linkages 4 and the two lower linkages connected rotatably to the upper linkages and is driven by a common motor 3, this construction is not critical and any other constructions may be utilized so long as it provides the vehicle with the same functions. For example, as shown in FIG. 10, a leg mechanism may be used in which a rod 12 is mounted rotatably on the main body 1, one end of which is connected to a rod of a piston 31 and the other end of which is connected to a walking arm 13 and the arm 13 which has a lower end in contacting with the surface and supports the main body is connected through a support arm 14 to the main body.

On such leg is mounted to each corner of the main body and driven by a piston to reciprocate each arm 13. In this case, by appropriately regulating the times at which fluid pressure is applied to each piston cylinder, the respective-legs will move reciprocally with any desired phase differences, so that the main body readily moves straight or snakes.

In the walking movement of the vehicle provided with four legs, the body is usually supported by three of the legs. However, when the three legs have the same walking and return strokes, one of the three legs must slip on the surface in the direction of movement of the vehicle. This slipping leg may be obstructive to the stability of walking and, for example, when the slipping leg encounters some protrusion or recess on the road surface and is caught thereby, the direction of the vehicle tends to be changed or the walking movement itself may be stopped.

In order to eliminate such slippage of the leg and ensure stable walking the legs other than the legs which, at that time, are in contact with the surface must be returned quickly and replaced on the surface at a forward position, all before the center of gravity has had time to shift outside the triangle defined by the three lines connecting the legs supporting the weight.

Assuming that the end point of each of the legs performs a walking motion, the cycle time of which is 2z, one walking stroke S of the leg supporting the weight corresponds to a half cycle, that is, 2. Accordingly, when the phase difference between the adjacent legs supporting the weight of approximately z/3, the gravity center must be within the triangle. Furthermore, it is necessary to lift the leg other than the three and bring it forward by strokes S while the three legs are moving by approximately z/3, respectively. Accordingly, the moving velocity of the leg in the return stroke should be about three times the velocity in the walking stroke.

The above relation will be described arithmetically with reference to FIG. 11.

FIG. 11(a) to 11(2) showthe phase relations of the four legs at the time the legs are in contact with the surface during one walking cycle.

When the legs I, II, III and IV are in the state shown in FIG. 11(a), the legs 11, IV and I move backwardly by 8A, 6B and 8D, respectively for the first time interval z/3 to move the main body forward.

While the leg III is quickly moved forward by 80,, as shown in FIG. 11(b). During the next z/3, the legs II, IV and III move backward by 6A 6B 6C respectively while the leg I moves forward by 8D,, as shown in FIG. 11(0) and thus the respective legs move backward and forward, alternatively.

As will be seen from FIG. 11(e), the travel distances of the respective legs have the following relations.

Taking the average of the traveling distances for every z/3 as 5 and SA4=SB3=SC1:SD2=S S can be expressed as Equation (4) differentiated by time is as follows ds/dl=V =3V5 (5) That is, the mean shifting velocity V of the leg in the return stroke must be three times the mean shifting velocity V8 of the leg in the walking stroke. However, in the return stroke, since the leg is lifted and then returned, the velocity V must be larger than three times the velocity S8.

As a mechanism for quickly returning the leg in the return stroke, any of various quick return mechanisms may be used. Examples of such mechanisms are shown in FIGS. 12 and 13 respectively.

The mechanism shown in FIG. l2,comprises spur gears 15 and 18 mounted on the shaft 7 (or 8) rotated by a suitable driving means, and fractional spur gears 17 and 19 mounted on a shaft 16. The gear 15 meshes with the gear 17 and, when the gear 15 is disengaged from the gear 17 after the shaft 16 is rotated fora predetermined fraction of one revolution, the gear 18 on the shaft 7 which has a larger size than that of the gear 15 and the gear 19 which has a smaller size than that of the gear 17 mesh with each other to thereby rotate the shaft 16 at a higher speed for the remaining cycle than that established by the meshing of the gears 15 and 17, so that the leg can be quickly driven for a particular time by the eccentric pin 10 on the arm 9 mounted on the shaft 16. On the other hand, in order to partially vary the speed of a leg in the walking stroke, it may be possible to provide a suitable number of fractional spur gears, which are similar to the gear 17 but have different sizes, on the shaft 16 and a corresponding number of spur gears having different sizes accordingly and meshing with the additional fractional gears for different angles so that the rotation of the shaft 7 can be transmitted to the shaft 16 at any desirable ratios for different time intervals.

In another mechanism shown in FIG. 13, a spur gear 20 mounted on the driving shaft 7 (or 8) rotated by a suitable driving means meshes with a fractional spur gear 21 mounted on the shaft 16. The gear 21 is biased by a spring 22 in the clockwise direction. Upon the rotation of the gear 20 in the anticlockwise direction, the gear 21 is rotated clockwise and, after a predetermined fraction of one revolution is completed and the gear 21 is disengaged from the gear 20. It is quickly brought into reengagement with the gear 20 by the effect of the spring 22, to thereby move the leg driven by the eccentric pin quickly for a particular time interval.

In the leg mechanism shown in FIG. 10 which utilizes the reciprocal motion of a piston as its power source, the walking stroke and the return stroke of the leg can be desirably made slow and quick by making the feeding and exhausting velocities of the working fluid into and from the piston cylinder slow and quick.

Furthermore, the leg can be constructed as shown in FIG. 14 in which one end of a walking arm 23 having a rectangular slot 23 and an upper end of an auxiliary arm 24 having an elongated slot 24 and secured rotatably to the body 1 by pin 24a are rotatably jointed by a pin 28. A pin 27 fixed on a disk 25 is connected to and driven by the driving shaft 7 which is inserted into the slot 24. A pin 26 fixed to gear box 6 of body 1 on opposite side of the disk 25 is inserted into the slot 23' respectively so that by the rotation of the disk 25 the walking stroke and the return stroke are made slowly and quickly respectively.

The mechanism shown in FIG. is similar to that shown in FIG. 10 but, instead of the auxiliary arm 14, a second piston 29 is provided, so that the arm 13 is contracted in the return stroke by exhausting the fluid contained in the piston cylinder. In this manner, since the second piston 29 lifts and quickly returns the leg in the return stroke, the return motion itself becomes easy and there is no slippage of the leg.

The mechanism which is shown in FIG. 16 is a modification of that shown in FIG. 15. The piston 31 is used to reciprocate the walking arm 13 and the piston 29 when actuated in the return stroke lifts the leg so that the slippage of the leg is eliminated.

The mechanisms described heretofore are mere examples of mechanisms using eccentric gears, cam mechanisms and/or crank mechanisms which may be used herein.

In these mechanisms, the phase controls and the speed control in reciprocal motion of the respective legs may be performed manually or by an electronic computer.

As will be clear from the foregoing description, in the present four-legged walking vehicle, the construction of each leg is simple, and the phase control of the respective legs is easily performed. And the vehicle itself can walk in various modes. Furthermore, the present walking vehicle can be used for various purposes by regulating the phases and speeds of the respective legs. It can also be used for education purposes such as simulation of the various walking modes of animal, experiments and analysis thereof, etc. Furthermore, since the present walking vehicle can be made to move in unique and fantastic modes by changing the attitude thereof, it can be used for toys, etc.

What we claim is:

1. A walking vehicle which comprises in combination, a main body, four leg mechanisms, one of said four leg mechanisms disposed at each of four edge locations of the main body for supporting and driving the main body, each of said leg mechanisms having two upper linkages each having an elongated slot disposed along its body, and two lower linkages movably joined at one end, said upper linkages connected rotatably at their upper ends to the main body at their lower ends one each respectively to a lower linkage, said upper linkages crossed to form a generally X-shape, a rotating member disposed at each leg mechanism and having an eccentric pin disposed thereon, said pin projecting each of the elongated slots of the upper linkages, and means for rotating each rotating member relative each other such that one leg mechanism is rotated about out of phase relative to an adjacent leg mechanism whereby walking movement of the vehicle is effected.

2. The walking vehicle of claim I wherein each rotating member is provided with a means for quickly returning from a non-ground contacting position to an extended ground contacting position.

3. The walking vehicle of claim 2 wherein the means for quickly returning comprises a first relatively small spur gear and a second relatively large spur gear disposed along a first rotating driving means, a first relatively large fractional spur gear disposed to mesh relative said first spur gear and a second relatively small fractional spur gear disposed to mesh relative the said second spur gear, said fractional spur gears disposed along a second rotating driving means connecting to one of said rotating members, said first spur gear and said first fractional spur gear being in mesh relationship when said leg is in retracted non-ground contact, said second spur gear and second fractional spur gear being in mesh relationship when said leg is in ground contact position.

4. The walking vehicle of claim 2 wherein the means for quickly returning comprises a spur gear mounted on a driving shaft, a fractional spur gear mounted on a shaft disposed to one of said rotating members, said spur gear positioned for mesh contact with the fractional spur gear, and a spring member disposed for returning the fractional spur gear from non-meshing position to re-engagement with said spur gear.

Claims (4)

1. A walking vehicle which comprises in combination, a main body, four leg mechanisms, one of said four leg mechanisms disposed at each of four edge locations of the main body for supporting and driving the main body, each of said leg mechanisms having two upper linkages each having an elongated slot disposed along its body, and two lower linkages movably joined at one end, said upper linkages connected rotatably at their upper ends to the main body at their lower ends one each respectively to a lower linkage, said upper linkages crossed to form a generally Xshape, a rotating member disposed at each leg mechanism and having an eccentric pin disposed thereon, said pin projecting each of the elongated slots of the upper linkages, and means for rotating each rotating member relative each other such that one leg mechanism is rotated about 180* out of phase relative to an adjacent leg mechanism whereby walking movement of the vehicle is effected.

2. The walking vehicle of claim 1 wherein each rotating member is provided with a means for quickly returning from a non-ground contacting position to an extended ground contacting position.

3. The walking vehicle of claim 2 wherein the means for quickly returning comprises a first relatively small spur gear and a second relatively large spur gear disposed along a first rotating driving means, a first relatively large fractional spur gear disposed to mesh relative said first spur gear and a second relatively small fractional spur gear disposed to mesh relative the said second spur gear, said fractional spur gears disposed along a second rotating driving means connecting to one of said rotating members, said first spur gear and said first fractional spur gear being in mesh relationship when said leg is in retracted non-ground contact, said second spur gear and second fractional spur gear being in mesh relationship when said leg is in ground contact position.

4. The walking vehicle of claim 2 wherein the means for quickly returning comprises a spur gear mounted on a driving shaft, a fractional spur gear mounted on a shaft disposed to one of said rotating members, said spur gear positioned for mesh contact with the fractional spur gear, and a spring member disposed for returning the fractional spur gear from non-meshing position to re-engagement with said spur gear.

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