US3368292A

US3368292A - Vehicle for conditioning snow slopes, and for transportation thereon

Info

Publication number: US3368292A
Application number: US464496A
Authority: US
Inventors: Prinoth Ernesto
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-06-19
Filing date: 1965-06-16
Publication date: 1968-02-13
Anticipated expiration: 1985-02-13
Also published as: DE1780647B2; SE328488B; DE1658409B1; DE1780647A1; CH460545A; DE1780647C3; GB1107053A; GB1107052A; DE1455735A1

Description

2 2 9 t w M 3, w 3 w m mm Feb. 13, 1968 E. PRINOTH VEHICLE FOR CONDITIONING SNOW SLOHES,

FOR TRANSPORTATION THEREON Filed June 16, 1965 INVENTORI esi7= ILu-ok Feb. 13, 1968 E. PRINOTH VEHICLE FOR CONDITIONING SNOW SLOPES AND FOR TRANSPORTATION THEREON 4 Sheets-Sheet 5 Filed June 16, 1965 INVENTOR, ERNESTO PRINOTH Feb. 13, 1968 E. PRINOTH I 3,363,292

VEHICLE FOR CONDITIONING SNOW SLOPES AND FOR TRANSPORTATION THEREON Filed June 16, 1965 4 Sheets-Sheet 4 INVENTOR;

BJWAJQM United States Patent M 3,368,292 VEHICLE FOR CONDITIONING SNOW SLOPES, AND FOR TRANSPORTATION THEREON Ernesto Prinoth, Villa Espcria, Bolzano, Italy Filed .inne 16, 1965, Ser. No. 464,496 Claims priority, application Italy, June 19, 1964, 13,430/64; May 24, 1965, 11,370/ 65 6 Claims. (CI. 3710) This invention concerns a tracked vehicle having multiple tracks forming a single or double band capable of resilient adaptation to the ground both transversely and longitudinally, particularly for conditioning the surface of the snow on ski slopes, and for transport over the snow.

Ski slopes require conditioning in order to consolidate freshly-fallen, light powder snow, or to break up and pulverize the hard, crusted surface of old snow. I have found that this is best accomplished by running over the snow with a light-weight, broadtrack vehicle, such as the present invention, which breaks up the crust,

squeezes out entrapped air in the upper layer of snow,

and lightly compacts the snow. When the snow is very light, it cannot be packed, as there is not enough internal cohesion for the crystals to cling together. However, if light snow is allowed to stand for a period of 2 to 5 hours after being treated, the snow crystals appear to undergo a metamorphosis, resulting in excellent internal cohesion. Thus, immediately after running over fresh powder snow with the machine of the present invention, the upper layer of snow shows no improvement in its load-bearing capacity, yet a few hours later that same snow becomes firm, and is able to support the weight of a man.

In order to execute the above work rapidly and without risk that the vehicle may sink, slide sideways on snow slopes extending transversely to the direction of travel or stop in hollows of opposed declivity, it is necessary that the vehicle exert a uniform pressure per unit area over a large width of track with a force sufiicient to squeeze out the air from the upper stratum of the snow which then consolidates automatically after a relatively short period.

To achieve this object the invention proposes a vehicle on a generally rectangular chassis, on the side frame members of which are supported the independent and resiliently flexible shafts of a centre train of wheels around which is carried a band loosely connected on both sides to several endless belts which are symmetrically distributed, parallel to the longitudinal axis of symmetry of the centre train of wheels. The band is connected to said belts by means of sections secured to the outer surface of the belts in a direction extending transversely to said train and having an external cutting angle, thus acting as cleats for gripping the ground. The skeleton framework formed by said cleats unites all the belts in the form of a band as wide as the chassis and wound round the train of wheels, the resilient adaptability of the train to the longitudinal outline of the earth being transmitted to the band of belts which in turn, by the loose transverse connection between the various belts, adapts itself in a flexible manner to the transverse outline of the snow surface to which all the points of the band conform at every moment of the travel of the vehicle.

The changes in direction of the band of belts described above are effected in various manners.

In order to consolidate a strip of snow which is wider than the band, two of the vehicles may be flexibly connected together side by side by means of hinges having a common fore-and-aft extending hinge axis. In this case, steering is effected through differential acceleration and/ or braking of the engines, and to this end the respective engine controls are coupled so that the engines and brak- Patented Feb. 13, 1968 ing of both vehicles can be controlled from one of the vehicles. More especially for levelling still wider paths or open spaces covered with snow, two vehicles are connected in side by side relationship by a planing frame extending transversely of their tracks and hinged to the vehicles at their lateral ends.

The planning frame is adjustable in height relative to the vehicles chassis, and is provided with cutters extending transverse to the direction of forward travel. Means are also provided for varying the inclination of the frame so as to adjust the cutting angle of the cutters, and operative connections for this and the height adjustment are provided for control from the drivers position in the vehicles. The hinges connecting the frame to the chassis are preferably resilient, such as a block of rubber carried on the chassis and adjustably mounted in sliders on the frame, traction means such as a metal chain being provided to receive the tractive forces between the chassis and the frame.

According to a further form of the invention when it is necessary to consolidate a strip of snow as wide as the band, for example a pathway, with a high degree of compression, two vehicles are connected together one behind the other by means of a ball and socket joint and flexibly connected hydraulic cylinders, which transmits from the rear vehicle a steering couple to the front vehicle. Because of its low pressure per unit of ground, the front vehicle slides laterally into the new direction of travel oi which it is followed by the rear vehicle. In such a case, the propulsion motors of the two vehicles work in unison.

When, finally, a vehicle must for any reason, travel alone there is connected to the ball joint and to the hydraulic cylinder steering device mentioned in the first form of the invention, a bar provided with hollow groundengaging members shaped like the prow of a boat, which plows through the snow so that, by operating the steering device, said bar operates in the same manner as a vehicle in front.

Other features and advantages of the invention will be apparent from the accompanying drawings which illustrate one of the possible embodiments of the above described invention. In the drawings:

FIGS. 1, 2 and 3 show schematically plans, respectively, of two vehicles according to the invention travelling one behind the other and side by side, and a vehicle according to the invention travelling alone;

FIGS. 4, 5 and 6 show schematically and on an enlarged scale relative to the preceding figures, a side view of a vehicle, a plan of its chassis with a band of belts, and a front view of the band from the direction of the arrow A of FIG. 5;

FIG. 7 is a front view of a pair of vehicles in a side by side working position, connected by a planing frame;

FIG. 8 is a plan of a rigid planing frame according to the invention, shown on an enlarged scale; and

FIGS. 9 and 10 are side views of the connection of the planing frame to the chassis of a vehicle, in the withdrawn position and the working position, respectively.

With reference to FIGS. 1, 2 and 3, a single track vehicle is indicated as a whole by 1, while in the arrangement using two vehicles one behind the other, the front vehicle is indicated by 1a and the rear vehicle by 1b. In the arrangement with two vehicles side by side the right vehicle is indicated by 1a and the left by 1b. As will be seen in the above figures and more clearly in FIG. 4, each vehicle has a motor 2 preferably of the gasoline engine type to facilitate starting, a change-speed gear box 3, a backrest 4 with incorporated fuel tank, a seat 5 for the driver, a seat 5a for the passengers and a pair of levers to control the engines (accelerator in the forward 3 position and brake in the rear position) indicated by

references

6, 6a, 6b, and a lever 7 to control the steering device.

When travelling with two vehicles one behind the other, as shown in FIG. 1, each vehicle has two levers 6, which are normally movable independent of one another, but which are connected together so as to move as one when the vehicles are joined in tandem. The levers 6 of the front vehicle are then connected to the levers 6 of the rear vehicle by any conventional motion-transmitting means (not shown) such as a Bowden cable, for example, so that the driver, seated on one of the two vehicles, preferably the front one, operates a lever 6 and controls both of the engines 2 simultaneously and in the same manner. The steering device is controlled by means of the lever 7 which is near to the driver, the lever 7 of the other vehicle being disconnected, so that it is inoperative. The two vehicles are connected together by a removable rigid triangle 8, the base of which is hinged to one vehicle and the vertex of which is connected by a ball and socket joint to the other vehicle. The unit is also provided with a removable steering device formed, for example, of two hydraulic cylinders with pistons and rods indicated as a whole by 9 and 9a respectively. The heads of the cylinders are loosely connected to the base of the triangle 8, and the bases of the rods are connected by means of ball and socket joints to the vehicle which is connected to the ball and socket joint at the vertex of the said triangle.

If it is desired to make a turn, the lever 7 is moved transversely in the desired direction, for example, to the right, so that pressurized fluid is fed to the cylinders so that a piston 9 is pushed out and the piston 9a is withdrawn and the front vehicle passes, as shown in FIG. 1,

from the position In to the position 1a.

The universal connection of the two vehicles makes it possible to adapt the unit to the longitudinal contour of the ground. No change, reversing the arrangement relatively to the drawing in FIG. 1 of the unit formed by the triangle and the steering device, is necessary.

During travel with two vehicles disposed side by side (FIG. 2), the steering levers 7 are locked, and the

connections

8, 9, 9a, are cleared away.

The two vehicles are connected together by hinges 11 which enables the unit to adapt itself to the transverse contour of the ground. On each vehicle, the lever 64:, 6b, adjacent the respective engine operates to advance the engine throttle when pushed forwardly from the neutral center position, and to apply the brakes when pulled rearwardly therefrom. The levers 6b, 6a, remote from the engines of the respective machines are independent of the other levers adjacent their respective engines. The lever adjacent the engine of one vehicle is connected by any suitable motion-transmitting means (not shown), such as a Bowden cable or the like, to the lever remote from the engine of the other vehicle, so that the levers connected in this manner are moved together and in the same direction through the same angular distance.

In FIG. 2, levers 6a are connected together, and so are levers 6b. If the driver, seated for example on the right hand vehicle 1a, wishes to turn left, he pushes the lever 6a forward, thus accelerating the engine of the right-hand vehicle and in this manner turning the unit to the left in a turn of relatively large radius, whereas the same displacement of the lever 6a of the vehicle on the left will have no result. If it is desired to reduce the radius, it is necessary to brake the left engine, which is effected by pulling back the lever 6b of the right vehicle which acts through the aforementioned motion-transmitting means to move the lever 6b rearwardly on the lefthand vehicle, thereby operating the brake. It will thus be seen that the operating interconnection between the control levers 6a and 6b of the two vehicles enables the engines to be operated at different speeds, or one engine to be accelerated and the other braked, to turn the unit to the right or left.

For levelling open snow covered spaces or broad tracks, the hinges 11 connecting two

individual vehicles

1a, 1b, travelling side by side as shown in FIG. 2, are replaced as shown in FIGS. 7 to 10' by a rigid, rectangular frame of suitable length in the direction transverse to the line of forward travel. The lateral ends of the frame are flexibly connected to the vehicles, and are also adjustable both vertically and angularly with respect to the ground. Both long sides of the frame have cutters mounted thereon, with their cutting edges facing forwardly, and these cut ters slice through the snow in the same manner as a carpenters plane with a double blade.

However, when the pair of vehicles has to level the track, the frame is lowered and inclined until it sweeps more or less parallel with the track itself, the elevations of which are cut away, while the frame uniformly distributes the snow on the track.

When, however, the pair of vehicles must be transported without planing, the frame is suitably raised.

A planing frame according to the invention shown in FIG. 8 is constructed in the form of an elongated rectangle 25 of square steel, provided with reinforcing diagonals 26 of metal sections. In line with each lower face of the side members 25 there are

welded cutters

27 and 28 respectively, the cutting edges of the two cutters being turned in the same direction.

The system for the control of the height and inclination of the planing frame may be accomplished by various conventional remote control systems from the driving position. In the embodiment shown, remote control is effected by means of four electric motors 30, each located on an angle of the planing frame and, each motor actuating a screw jack 31 through a reduction gear 29. AS will be seen in FIGS. 9 and 10 the lower end of the jack shaft is welded to the upper face of a side member 25' of the planing frame, while the upper end of the frame is connected to a motor 30 and associated reduction gear 29. Formed on the face of the shaft turned towards the vehicle is a slot through which projects a part of the screw jack slider with a female thread (see FIG. 7). This projection is connected by means of a metal plate and vulcanization to one of the faces of a rubber joint 32 of the silent block type, the opposed face of which is in turn vulcanized to a metal plate 33, detachably secured to the adjacent side member 12 of a

single vehicle

1a, 1b (see FIG. 8).

However, when a motor 3% is working, the

whole unit

29, 30, 31 is elevated together with the corresponding angle of the

frame

25, 26, since the endless thread of the jack screws itself in the female screw portion thereof, which is secured to the chassis 12 of the vehicle.

In order to eliminate tensile stresses from the rubber of the resilient joints 32, such as may occur during the turning of the double vehicle In and 1b, lengths of small chain and like (not shown for clarity) are incor porated in the joints 32 in the longitudinal direction of the planing frame and secured with minimum initial tension at one end to a plate 33. The opposite end of the chain is attached to the metal plate connecting the joint to the sliding member of the jack 31. When the said chains extend, however, they take the tension and when they are released, they permit the joint 32 to work under compression.

The two motors 30 on each vehicle are controlled by flexible electric cables connected to a control panel arranged in the driving position. The driver may therefore effect all the various operations controlling the height from the ground and the inclination of the planing frame with respect thereto.

It should be noted that the cross acting as braces for the planing distribute on the track the wave cut away by the front cutter 27.

pieces 26, apart from frame, also serve to of fragments of snow Owing to the fact that the planing frame extends transversely between the two vehicles, the

cutters

27 and 28 closely follow the contour of the ground; a feature which is not realised with any prior apparatus known to me.

If a vehicle has to travel alone, the ball joints of the triangle 8 and the points of engagement of the steering system, for example the bases of the piston rods 9, 9a, are connected as shown in FIG. 3 to a turning device indicated as a whole by 10. This device consists of a bar 10a, to the lower part of which are secured hollow members 1012, shaped like the prow of a boat which, during travel, plow through the snow without sinking too deeply therein, with minimum resistance in the direction of travel and maximum resistance in a direction extending transversely thereof. The two control levers 6 of the engine are connected together and when the steering lever 7 is inclined over to one side or the other, a turn is executed as described with reference to FIG. 1. FIG. 3 shows the lever 7 inclined to the left, which causes the vehicle to turn in this direction under the steering torque transmitted by the members 10b through the rotating bar 10a and the triangle 8.

The arrangement of the band of belts is shown in FIGS. 4 and 6. Situated on the trans-verse centre line of the rectangular chassis 12 is a flexible, resilient shaft 18, fixed at its ends to resilient supports 18a of rubber or the like which are, in turn, secured to the chassis on which the shaft 18 is thus spring mounted. On the longitudinal centre line of the chassis, a rocker 13 is secured to the shaft 18, and mounted on opposite ends of the rocker are the axle shafts of a pair of

identical bearing wheels

14, 14, so that the torsion caused by the oscillations of the rocker 13 is fully absorbed by the rubber supports 18a.

The lightness and simplicity of the above-described construction for spring-mounting the

center bearing wheels

14, 14 on the chassis, is one of the advantageous features of the invention.

In line therewith the chassis has at both ends a pair of twin rubber tired driving and supporting wheels 15, 15 'keyed on the resiliently

flexible shafts

17, 17, both of which are supported at their ends in rocker bearings located in the side frame members of the chassis 12. The rear shaft is supported in fixed bearings 17a, while the front shaft is carried in bearings 17b which are longitudinally displaceable under the action of a belt stretcher, having a cam shaft 19.

The driving means are provided with resiliently deformable pneumatic tires which present a path-making device moulded with teething of a predetermined modulus, meshing with corresponding metal projections of the belts.

After operating the belt tensioning devices, the two shafts 17 are bent towards each other, as shown in FIG. 5, and remain in this condition during travel. Two advantages are achieved by this:

(1) Powerful contact is obtained between wheels and belts, so that the latter are always driven by the former in any condition of travel, in each case ensuring a powerful contact of the band with the ground.

(2) The shafts 17, being bent in the horizontal plane, have a better spring suspension action under vertical impulses due to the roughness of the ground.

The initial resilient spring bending of the shafts 17, from which the above advantages are derived, is made possible by the fact that the ends of said shafts are supported at opposite sides of the relatively wide chassis, and there is thus a considerable distance between the support points.

However, due to the initial bending, contacts and spring mounting are improved in a simple and economical manner.

Since the shafts 17, which as explained hereinafter are also driving shafts of the wheels 15, are simultaneously stretched continuously with flexion alternating in the horizontal plane and with torsion and/or are also occasionally stretched with flexion in the vertical plane they are constructed of an alloy steel of very great strength.

The transmission of the driving couple to the wheels, 15, 15, which are keyed on the

shafts

17, 17, is effected as follows: the change speed gears 3 located, as shown in FIG. 1, in a position at the side, drives a sprocket wheel 22 over which is passed a chain 21 which, in turn, is passed over a sprocket wheel 20, keyed near one of the supports 17a of the rear shaft 17 which is thus kept rotating. Near the wheel 24 there is keyed on this shaft a second sprocket wheel (not shown) over which passes the chain 16, in turn, meshing with a sprocket wheel (not shown) mounted near one of the supports 17b of the rear shaft 17, which is then kept rotating. The fact that the engine power is transmitted to the

wheels

15, 15 near one of the side frame members of the chassis makes it possible to occupy the entire width thereof with a single band of belts.

The band of belts of the invention is indicated by 23 as a whole, and is composed of a centre belt 23:; wound round the train of

wheels

14, 15, intermediate side belts 23b, and end side belts 23c. As shown in FIG. 5, which is a top view of the band 23, the centre belt 23a of each opposed band of the chassis is strongly but loosely connected to the

side belts

23b and 23c; on the right, in the direction of forward travel of the vehicle, by means of the cleats indicated by 24a, and on the left by the cleats 2412. These cleats are formed by metal strips of triangular cross-section (see FIG. 4), the apexes of which face outwardly and bite into the snow as the vehicle advances over the ground.

All the

cleats

24a and 24b unite the

various belts

23a, 23b and 23c into a single band 23, which is resiliently flexible transversely of the vehicle, and is wound over a train of

wheels

14, 15, the looseness of which, in the longitudinal plane of the vehicle, is obtained, according to the invention, by means of the independent spring mounting of the

shafts

17 and 18 and by means of the resilient oscillation of the rocker shaft 13 of the bearing wheels 14 in the resilient supports 18a by means of the shaft 18.

I claim:

1. Apparatus for conditioning ski slopes and for transport over the snow, comprising:

a pair of individual tracked vehicles disposed side-byside, and connected together along their adjacent sides by flexible hinge means, whereby either of said vehicles can tilt with respect to the other about the pivot axis of said hinge means;

each of said vehicles comprising a generally rectangular chassis having side frame members with wheel shaft supports mounted thereon;

transverse shafts mounted on said supports;

wheels mounted on said shafts;

an endless belt track band trained around said wheels, said track band being substantially the same width as said chassis;

a motor mounted on each of said chassis and having a driving connection to its respective track band; and

control means on at least one of said vehicles operable to regulate the driving speed of both of said vehicles, whereby the track bands of both vehicles may be driven at the same speed or the track band of one vehicle may be accelerated and the track band of the other vehicle braked, so as to steer the unit.

2. The apparatus of claim 1, further characterized by:

control means on each of said vehicles comprising independently operable first and second motor contro s;

said first motor control on each of said vehicles being connected to the motor driving that vehicle, so as to operate the same;

said second motor control being connected to the motor driving the other Vehicle, whereby the operator can control the motors of both vehicles by manipulating said first and second motor controls on either of said vehicles; and

each of said motor controls being operable to accelerate its respective motor when moved in one direction from a neutral midpoint, and to brake its respective motor when moved in the other direction.

3. Apparatus for conditioning ski slopes, comprising:

a pair of laterally spaced, individual tracked vehicles;

an elongated leveling frame disposed transversely between said vehicles;

a pair of fore-and-aft spaced, flexible connections joining each of the laterally outer ends of said frame to the sides of said vehicles, each of said pairs of connections being disposed in a line generally parallel to the line of forward travel, and said connections being resilient to allow each of said vehicles to tilt with respect to said leveling frame about an axis passing through said pair of connections as said apparatus follows the contour of the ground; and

cutters mounted on said frame and extending transversely to the direction of forward travel, said cutters being operable to slice through the top surface of the snow to break up the crust and level the surface, said frame serving to distribute the snow more or less evenly across its width as the machine advances.

4. The apparatus of claim 3, wherein said flexible connections include means for raising and lowering the ends of said leveling frame with respect to the associated vehicle, and for varying the inclination of the frame with respect to the ground.

5. Apparatus for conditioning ski slopes and for transport over the snow, comprising:

a pair of individual tracked vehicles disposed one in front of the other and connected together in tandem;

the connection between said vehicles consisting of a rigid triangular draft member hinged along one side to one of said vehicles for vertical swinging movement, and a universal joint connecting the opposite apex of the triangle to the other vehicle; and

steering means in the form of a pair of hydraulic rams, each of which is flexibly connected at one end to said one vehicle and at the other end to said other vehicle on opposite sides of said universal joint and at points spaced laterally outwardly therefrom, each of said hydraulic rams comprising a cylinder with associated piston rod;

said hydraulic rams being controllable from one of said vehicles to force said vehicles into angled relationship to one another, thereby causing the apparatus to turn in one direction or the other, each of said vehicles has its own propulsion motor, and each vehicle has a motor control level, and means interconnecting the control levels of said vehicles whereby movement of either control lever causes simultaneous and corresponding movement of the other control lever.

6. A tracked vehicle for travel on snow, comprising:

a chassis having an endless belt track band of substantially the same width as said chassis and propulsion means for driving said track band;

steering means for said vehicle, comprising a rigid triangular member hinged along one side to the front end of said chassis for vertical swinging movement, and a transverse bar connected by a universal joint to the opposite apex of the triangle;

ground-engaging members mounted on said bar, said members being shaped to have minimum resistance in the direction of forward travel and maximum resistance in the direction transverse thereto; and

a pair of hydraulic rams, each of which is flexibly connected at one end to the front of said vehicle, and at the other end to said bar on opposite sides of said universal joint and at points spaced laterally outward therefrom, each of said hydraulic rams comprising a cylinder with associated piston rod;

said hydraulic rams being controllable from said vehicle to force said bar around to an angled relationship, whereby said ground-engaging members cause said vehicle to turn in one direction or the other.

References Cited UNITED STATES PATENTS 655,686 8/1900 Cawley 305-29 1,310,604 7/1919 Burgess 18014 2,051,864 8/1936 Knox et al 28O124.3 2,367,751 1/1945 Bombardier. 2,436,681 2/1948 Swenson. 2,749,189 6/1956 France et a1 1805 X 2,925,873 2/1960 Laporte 1805 2,933,143 4/1960 Robinson et al 180-14 3,011,576 12/1961 Howes 30535 X 2,112,559 3/1938 Davidson 1805 X 2,272,619 2/1942 Flynn et al. 180-5 3,157,239 11/1964 Bernotas 180-51 FOREIGN PATENTS 620,491 5/1961 Canada.

1,110,037 10/1955 France.

ABRAHAM G. STONE, Primary Examiner.

R. L. HOLLISTER, Assistant Examiner.

Claims

6. A TRACKED VEHICLE FOR TRAVEL ON SNOW, COMPRISING: A CHASSIS HAVING AN ENDLESS BELT TRACK BAND OF SUBSTANTIALLY THE SAME WIDTH AS SAID CHASSIS AND PROPULSION MEANS FOR DRIVING SAID TRACK BAND; STEERING MEANS FOR SAID VEHICLE, COMPRISING A RIGID TRIANGULAR MEMBER HINGED ALONG ONE SIDE TO THE FRONT END OF SAID CHASSIS FOR VERTICAL SWINGING MOVEMENT, AND A TRANSVERSE BAR CONNECTED BY A UNIVERSAL JOINT TO THE OPPOSITE APEX OF THE TRIANGLE; GROUND-ENGAGING MEMBERS MOUNTED ON SAID BAR, SAID MEMBERS BEING SHAPED TO HAVE MINIMUM RESISTANCE IN THE DIRECTION OF FORWARD TRAVEL AND MAXIMUM RESISTANCE IN THE DIRECTION TRANSVERSE THERETO; AND A PAIR OF HYDRAULIC RAMS, EACH OF WHICH IS FLEXIBLY CONNECTED AT ONE END TO THE FRONT OF SAID VEHICLE, AND AT THE OTHER END TO SAID BAR ON OPPOSITE SIDES OF SAID UNIVERSAL JOINT AND AT POINTS SPACED LATERALLY OUTWARD THEREFROM, EACH OF SAID HYDRAULIC RAMS COMPRISING A CYLINDER WITH ASSOCIATED PISTON ROD; SAID HYDRAULIC RAMS BEING CONTROLLABLE FROM SAID VEHICLE TO FORCE SAID BAR AROUND TO AN ANGLED RELATIONSHIP, WHEREBY SAID GROUND-ENGAGING MEMBERS CAUSE SAID VEHICLE TO TURN IN ONE DIRECTION OR THE OTHER.