US3119630A

US3119630A - Means for steerably interconnecting vehicles in tandem

Info

Publication number: US3119630A
Application number: US80218A
Authority: US
Inventors: Robert J Oliver
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1961-01-03
Filing date: 1961-01-03
Publication date: 1964-01-28
Anticipated expiration: 1981-01-28

Description

Jan. 28, 1964 R. .1. OLIVER MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM '7 Sheets-Sheet 1 lll\ m.

Filed Jan. 3, 1961 Jan. 28, 1964 R. J. OLIVER 3,119,639

MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM Filed Jan. 3, 1961 7 Sheets-Sheet 2 inven or R. J. OLIVER Jan. 23, 1964 MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM '7 Sheets-Sheet 3 Filed Jan. 5, 1961 NEE QM Ev Maw QQN Jan. 28, 1964 R. J. OLIVER 3,119,630

MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM Filed Jan. 5, 1961 7 Sheets-Sheet 4 R. J. OLIVER 3,119,630

MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM Jan. '28, 1964 7 Sheets-Sheet 5 Filed Jan. 3, 1961 2116724071 9 Robert a?) 0Z2 #2? R. J. OLIVER 3,119,630

MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM Jan. 28, 1964 7 Sheets-Sheet 6 Filed Jan. 3, 1961 R. J. OLIVER Jan. 28, 1 964 MEANS FOR STEERABLY INTERCONNECTING VEHICLES IN TANDEM 7 Sheets-Sheet 7 Filed Jan. 3, 1961 w Q 1 5 w w 11 1 8 J0 MW L in a z/ 77 for;

J OZZY/27" United States Patent G 3,119,630 MEANS FOR STEERABLY INTERCONNECTENG VEHICLES IN TANDEM Robert J. liver, Lyons, Ill., assignor to International Harvester Company, Chicago, Ill., a corporation of New Jersey I y Y Filedllan. 3, 1961, Ser. No. 80,218

' 11 Claims. (Cl. 230*402) This invention relates to tandem connected components movable alongthe ground, especially tractors, and to means for connecting a plurality of components, especially tractors, in tandem and forsteering the same.

A prineipal object of the invention in preferred forms thereof i's'to provide for the interconnection of a plurality of tractors of the type normally having spaced forward and rearward ground-engaging support means, such as wheels, in tandem and conversion thereof into a tandem tractor unit in which contact with the ground is only through the rearward support means of the tractors.

Another important object is to provide for such interconnection and conversion as above set forth so as not to increase the stresses the structures of the component tnactors of the unit are under over those they are under as separate tractors. More paiticularly, it is an object to provide for such interconnection and conversion of tractors into a unit as above set forth not only soas not to increase the stresses in the component tractors of the unit due to 4 bending moments, but also so as not to impose any tappreciable torsional stresses therein which the tractors are not intended to withstand, while operating the unit in a curved path or during turning.

Another object is to provide means for interconnecting tnactors for the production of units as above set forth comprising a unitary rigid structure which is articulated for movement about the vertical and longitudinally horizontal axes, when the unit is on level ground, and which can withstand the great bending moment and torsion to which it is subjected without binding and interfering with relative pivotal movementof the portions of said structure about said axes.

' A further object is to provide means for interconnecting tractors for the production of units as above set forth comprising a unitary structure which can be exceedingly quickly and easily unitarily attached to and detached from the tractors during formation and disassembly of the unit,

respectively. 1

Still another object is to provide interconnecting means between tractors for the production of the unit as above set forth comp-rising a unitary structure from which the front tractor can be quickly and easily disconnected in a few seconds for independent use, leaving said stnucture still connected to the trailing tractor and ready for instant re- COIIIICCCIOII'Wl'lEIl the unit is again desired,

.Yet another object is to provide a tractor unit as above set forth in which receiving pocket or stirrup means are carried by the component tractors into which the aforesaid unitary structune is conveniently slipped and pinned during interconnection of the tractors and from which it-is quickly removed by knocking out the pins during disassembly of the unit.

A still further object is to provide rugged, simple, compact, and effective interconnecting means between the tnactors of the unit as above set forth which cannot become sprung or otherwise damagedby the roughest possible use.

Another object of great importance is to provide a tandem tractor unit in which the steeering wheel of the second tractor controls the steering of the unit through the means interconnecting the tractors in tandem.

A further object of great significance is to provide a tandem tractor unit in which the steering wheel of the second tractor controls the steering of the unit through the ent I964 ice will prevent the setting up of objectionable and destructive chattering or harmonic vibrations, such chattering or vibrations being prevented by a structure in which the control valve means of said fluid actuated means is connected directly to one of the portions of the means for connecting the tractors and further in which the control valve means senses only relative movement between the tractors inthe horizontal plane which is the only sensing desired, the latter functioning in-and thereby being necessary to the steering action of the .tandemized-tractors.

Other objects, advantages, and featuresof theinvention will appear from. the following illustnative description, read with the accompanying drawing, in which:

FIGURES 1 and 1A constitute a side-,elevational view of a tractor unit embodying a preferred form of the present invention;

FIGURES 2 and 2A constitute a top plan view of the unit of FIGURES 1 and 1A with the two tractors being shown in phantom lines for, convenience of illustration and of viewing; A 7

FIGURE 3 is an enlarged fragmentary side-elevational view of a mid portion of the unit of FIGURES 1 and 1A; FIGURE 4 is a fragmentary sectional view taken on line 44 of FIGURE 3 and in the direction of the arrows;

FIGURE 5 is an enlarged fnagmentary top plan view of the mid portion of theunit shown in FIGURE 3 with the rear' tractor omitted and certain parts shown bnoken ofi for. convenience of illustration and viewing. FIGURE 6 is a fragmentary portion of FIGURE 5 with the parts which are broken off in the. latter figure being shown and other parts being omitted for convenience of illustration and of viewing;

*FIGURE 7 is an enlarged view taken on line 77 of FIGURE 1A and in the direction of the arrows;

FIGURE 8.is an enlarged view taken on line 8-8 of FIGURE 1A and in the direction of the arrows;

FIGURE 9 is an enlarged view taken-on line 9-9 of FIGURE 1 and in the direction of the arrows;..and

FIGURE 10 is an enlarged fragmentary top plan vie as indicated by line 10-10 of FIGURE 1.

Referring to the drawing in detail, the tandem tractor unit therein depicted comprises a pair of wheeled tractors I and 2 of the type used on farms, from which the front wheel bolsters and included wheels have. been removed, and interconnecting or tandem hitch means between the tractors generally designated by the numeral 3. The interconnecting means includes. a rigid, articulated structure generally designated 4 which extends below the rear or trailing tractor 2 and at least .half of the front tractor 1, and means for connecting the substructure 4 to the tractors to be. pointed out below. 7

The structure 4 comprises a forward portion generally designated 5 extending under the front tractor 1 and a rear portion generally designated 6 extending under the rear tractor 2. The front portion 5 .has a pair of spaced, parallel, upwardly inclined, longitudinally extending members 7 of hollow rectangular section of decreasing height though constant width, from the rearmost ends to the forward ends of the members. The members 7' are connected to a U-shaped crossmember 8 by welding at the rear ends thereof. A pair of side plates 9 are welded to the opposite sides, respectively, of the member 8 to constitute a cross support structure with said member for the members 6. A longitudinally extending sleeve -11 containing a front and

rear bushing

12 and 13 is transversely centrally positioned between the upper and lower flanges of the U-shaped member 8, being suitably welded to the member. The web portion of the U-shaped member 8 contains a centrally located circular aperture of sufiicient size to receive the sleeve 11 which extends thereinto and is welded therearound to the web portion.

The rear portion 6 of the structure 4 comprises a pair of forwardly extending and converging side members 17 of hollow rectangular section of gradually increasing height, though constant width, from the rearmost ends to the forward ends of the members. The forward ends of the side members 17 are secured to a vertically extending, centrally bored, cylindrical terminal member 19 by welding. A reinforcing member 20 having an upper web portion and depending triangular shaped flanges along the opposite sides of the latter is joined to the side members 17 across the forward ends thereof and to the terminal member 19 welding along the several contacting edges thereof. A medially disposed fiat crossmember 23 is secured to the bottom surfaces of the side members 17 by welding. A V-shaped brace member 24 is welded at its forward ends to the side members 17 and along the bottom edge of the central portion thereof to the crossmember 23. A centrally disposed block or pad element 25 is welded to the bottom surface of the crossmember 23 while an L-shaped crossmember 26 having a horizontally disposed forwardly directed leg spaced below said block 25 is welded to the side members 17 and also along the rear edges of the crossmember 23 and block 25, thus forming a elevis with the crossmember 23 and block 25 for a purpose to be brought out below. A pair of downwardly inclined, forwardly converging, flat brace members 27 are additionally welded between the side members 17 and angle iron crossmember 26.

The front portion 5 of the structure 4 further includes a member generally designated 29 having a forwardly, A

longitudinally horizontally extending shaft portion 30 received within the sleeve 11 of the front portion and extending forwardly therebeyond. A collar 31 is secured to the front end of the shaft portion 30 by means of a pin 32, the collar abutting against the front surface of the sleeve 11 to retain the member 29 within the sleeve 11. The member 29 also has a yoke portion 34 having spaced, upper and lower rearwardly extending, coaxially vertically bored arm portions 35 and 36 provided with bushings 37 and 38. A vertical pin 40 extends through the bores in the portions 35 and 36 of the yoke 34 and also through the vertically bored terminal member 19 of the rear portion 6 of the structure 4, being secured to said member by means of a pin 41. Fittings 42 are provided for lubrication of the bearing surfaces of the yoke 34 and pin 40.

It should be apparent that the member 29 and the cooperative parts of the front and

rear portions

5 and 6 of the structure 4 provide a universal joint for relative movement of sai portions about the vertical and longitudinally disposed horizontal axes. There is no pivotal movement, however, about the transverse horizontal axis, normal to the longitudinal horizontal axis, the structure being substantially rigid in the longitudinal vertical plane for receiving and withstanding bending movements incident to the support of the tractors forward of the rear wheels thereof from which tractors the front bolsters and included wheels have been removed.

Four pocket or stiriup structures on each side of the tractors 1 and 2, namely 45, 46, 47, and 43 and 49, 50, 51, and 52, which constitute part of the interconnecting means 3, receive the structure 4, the latter being connected to each of the structures and consequently to the tractors by means of a single quickly insertable and removable horizontally disposed pin, as will be brought out below. The forward pocket or

stirrup structures

45 and 49 each comprises a flat plate 54 which is aflixed by means of three bolts to a pad 55 on the side of the clutch housing 56 of the front tractor 1, a generally L-shaped bracket member 57 welded to the plate 54 and extending outwardly therefrom and then downwardly and an inward guide and side wall member 59 having an upper vertical wall and inwardly inclined lower guide portion 60, the latter member being suitably welded at the bottom and the top thereof to the plate 54 and L-shaped bracket member 57, respectively. The outer leg of the member 57, the inner member 59, and the plate 54 are all horizontally coaxially bored, in the lower portions thereof, normal to the longitudinal axis of the tractor for reception of a single horizontally disposed pin 62 therethrough immediately below the received side member 7 of the structure 4 for retention of the side member within the pocket and consequent connection thereof to the tractor, which pin is secured in place by a quick attach and detach spring tension retained cotter element 63 located at the inner end of the pin.

The

rear pocket structures

46 and 50 connected to the front tractor 1 each comprise a pair of spaced

plate members

66 and 67 which are welded to each side of one of a pair of conventional axle carrier brackets 68 forming part of the

structures

46 and 59, respectively. Each of the latter brackets briefly consists of spaced, substantially vertically extending front and

rear members

69 and 70 of hollow square and U-shaped construction, respectively, between which a pair of bolts extend, clamping said two members to the rear axle carrier or housing 71 of the front tractor 1. The

plate members

66 and 67 are each outwardly crimped at 73 providing wider lower portions of the pocket structures for relatively snug reception of the side members 7 of the front portion 5 of the structure 4. The bottom portion of each of the

members

66 and 67 is also outwardly inclined for quickly and conveniently guiding or directing the side members 7 into received relation within the pocket structures. The

members

66 and 67 of each of the

structures

46 and 50 are horizontally coaxially bored normal to the longitudinal axis of the tractor for reception of a single horizontally disposed pin '76 which is secured in place by a quick attach and detach spring tension retained cotter element 77 as in the case of pins 62 and located at the inner end of the pin. The side members 7 of the structure 4 are also bored for passage of the pins therethrough when within the

pocket structures

46 and 50 for connection of the members to the front tractor 1.

The forward pocket or

stirrup structures

47 and 51 connected to the rear tractor 2 each have an outer plate 79 aflixed to a pad 81 on the side of the clutch housing 82 of the tractor by means of three bolts. Each of the structures also has an inner plate 84 welded to the plate 79, which inner plate extends inwardly and then downwardly presenting a vertical Wall portion 85. The plates 79 are crimped or offset inwardly to place their lower vertical wall portions in positions so as with the Wall portions 85 of the members 84 to relatively snugly receive the members 17 of the rear portion 6 of the structure 4. The

lower wall portions

86 and 85 of each of the

structures

47 and 51 are coaxially horizontally bored normal to the longitudinal axis of the tractor for reception of a single horizontally disposed pin 86 which is secured in place by a quick attach and detach spring tension retained cotter element 37 as in the case of the pins 62 and located at the inner end of the pin. The lower portions of the plates 79 are outwardly inclined for guiding reception of the side members 17 within the

pocket structures

47 and 51. The side members 17 of the structure 4 are also bored for passage of the pins 86 therethrough when within the

pocket structures

47 and 51 for connection of the members to the rear tractor 2.

The

rear pocket structures

48 and 52 connected to the rear tractor 2 each comprise a pair of spaced plate members 94' and 95' having

inturned flanges

96 and 97 along their rear edges thereof. The latter'flanges of each structure are welded along'each side of oneof a pair of axle carrier brackets 99 of identical construction to the brackets 68' on the front tractor and formingpart of the

structures

48 and 52. The lower portions of the plate members 94 and' 95 of each structure 48' and '52 are 'coaxially horizontally bored normal to the longitudinal axis of the tractor for reception of a single horizontally disposed pin 161 which is secured in place by a quick attach and detach spring tension retained cotter element as in the case of pins 62 and located at the inner endsof the pin. The lower ends of the plate members 94' and 95 are outwardly inclined to provide guide surfaces for ready ins'erti'on of the niembers17 of the structure 4 therebetween during assembly of the tractor unit. "The side members 17 of the structure 4 are also bored for passage of the pins 191 'thereth'rough when within the

pocket structures

48 and 52 for"connection of the members to the rear tractor 2.

A pair of spaced, generally triangular shaped plates 1'03 are welded to

the'inturned flanges

96 and 97 of the

plate members

94 and 95 of each of the structures 48 and 521 The heavy-duty drawbar 105 is connected to the

structures

48 and 52 between the rearwardly extending spaced plates 103 thereof by means of a pair of horizontally disposed pins 106 extending normally to the longitudinal axis of the tractor through the pairs of spaced'plates and received enlarged portions 107 of the drawbar welded to the forward ends of the side portions of the latter, which pins are suitably secured in place by quick attach and detach spring tension retained cotter elements also as in the case of the first-mentioned pins 62'. The fonvard enlarged portions 167 of the drawbar and also the spaced plates 1193 are, of course, bored for reception of the pins 1'06; The heavy duty drawbar 105 is additionally connected to the

structures

48 and 52 by 'a pair of fiatbottomed U-shaped members 168 welded to the d'rawbar on each side thereof and a pair of twisted straps 1139 pinned at their lower ends to the U-shaped members 108 and removably attached at their upper ends tothe rearward, U-shaped members 110 of the rear axle carrier brackets 99 by the usual eyebolts mounted on such carrier bracket members.

The structure 4 carries certain parts for steering the tractor unit which cooperate with the steering mechanism of the rear tractor 2. These parts includea doubleacting' hydraulic cylinder 117 pivotally connected at its rear end to the clevis formed by the members 25 and 26 by means of a verticalpin 11S and pivotally connected at its front end to a steering drive arm l ltl by means of a vertical pin 1 21; The arm 120 is pivotally connected at its inboard end between the lower'inturned andoutturned flanges of plates 1'22 and 123, respectively, which plates are welded to the outer and inner sides, respectively, of the left-hand member 17 of the structure 4, as viewed from the rear of the tractor unit, by means of a vertical pin 124. The outboard end of the arm 120 is pivotally connected to the rear end ofa link 128 by'means of a' vertical pin 126, the front end of which link is pivotally connected to a laterally extending portion 129 of th'eyoke portion 34 of the front portion 5 of the structure 4 by means ofa verticalpin 130.

Avalve 133 is' pivotally connected at its rear end to a transversely extending support lrnember .134'by means of a vertical pin 135 extending through a clevis member 136 threaded onto the end of the valve and through the support member received within the clevis, the support memher being welded at each side to the opposite side members 17 of the rear portion 6' of the structure 4. The valve is connected at its front end to one end of a transversely extending lever 13% by means of a vertical shoulder belt 139 extending through an element :137threaded onto the outer end of the stem of the valve and through the lever.

The opposite or outboard end of the lever 13% is pivotally connected to a link 1 41 by means of a vertical pin 142. The latter link is, in turn, pivotally connected at its opposite end to a depending bracket 143 connected to one side of the top portion 35' of the yoke 34' of the structure 4. The lever 13-8 is pivotally connected intermediate its ends to a steering'arm plate 146 by means of a screw 144 extending through a lever abutting washer and threaded into a pivot element 145 which is welded to the plate 146, the steering arm'plate 146 being Welded to a stop plate 147. The steering arm plate 146 and stop plate 147 are bolted as a unit 'to' the bottom of the mounting plate portion or flange'1'48 on the lower end of the steeringpivot shaft 150' of the rear tractor 2' by means of two diagonally disposed bolts 149. The pivot shaft is connected through a pinion 151 thereon to the steering wheel 152 through the usual sector 153 and worm, not shown, and universally jointed shaft means 1-55. Although the tractor 2 has been disclosed as having a mechanical steering mechanism, power steering maybe provided if desired, the present invention being equally cooperable with either steering mechanism of the tractor. The forward portion of the stop plate 147 makes abutting contact with stop elements 156 welded to a supporting member 157 in turn bolted to the under portion of the tractor 2 adjacent the front end thereof'so as to limit the amount of turning of the rear Wheels 158 of the forward tractor in either direction of the longitudinal center line of the tractor unit.

Fluid'line 169 connects the valve '133 to the source of hydraulic pressure, not shown, in the forward tractord, leaving the source of hydraulic pressure of the rear tractor exclusively available for operation of the machinery or equipment drawn by the tractor unit, while fluid line 161 connects the valve to the hydraulic reservoir, not shown, of the forward tractor;

Fluid lines

163 and 164 extend from the valve 133 to the front and rear portions, respectively, of the double acting cylinder 117 for operation of the piston of the cylinder and 'the attached linkage and connected front portion 5 of the structure 4 and front tractor 1 in the opposite directions of reciprocal movement thereof.

Considering the steering operation of the tractor unit, rotation of the steering wheel 15 2 of the rear tractor 2 in either direction causes corresponding rotation of the steering pivot shaft 150 and attached

plates

146 and 147, as seen in FIGURE 3. The intermediate pivot 145 of'the lever 5133, which is mounted off-center to the left, as vie-wed'fro-m the rear of the tractor unit, from the axis of rotation of the pivot shaft 150 and attached

plates

146 and 147, in turn, swings in anarc 166 (see FIGURE 6) about said axis in a clockwise or counterclockwise direction, as seen from above, depending upon the direction of turn of the steering wheel. inasmuch as the outboard pivot 1-42 of the lever 138 is stationary when this swinging movement first takes place, the opposite end of the lever swings forwardly and rearwardl-y for clockwise and counterclockwise rotation of the steering wheel, respectively, thus moving the inner valve member, not shown, of the valve 133 so as to internally connect the supply line 1641 with the

fluid lines

163 and 164, respectively, thus to initiate movement of the piston of the cylinder 117 and the connected linkage in a rearward and forward direction, respectively. The rearward and forward force, respectively, on the piston is transmitted through the piston rod and

links

120 and 128 to the projecting portion 129 of the yoke 34 and from thence as a clockwise and counterclockwise rotational force, respectively, as seen from above, into the rest of the front portion 5 of the structure 4, into the attached front tractor i1, and into the rear wheels of said tractor which are the front steering wheels of the four-wheeled tractor unit. During forward movement of the tractor unit the above action will obviously cause turning of the unit towards the right and left, respectively.

The inner valve member of the valve i133 has very limited travel, only moving a fraction of an inch in each of the opposite directions from a neutral position in which the lines 164} and 161 are connected to neither of the

lines

163 or 164, thus to maintain the cylinder 117 and the connected linkage, from portion of the structure 4, and attached front tractor in a state of rest in whatever position the piston of the cylinder, linkage, portion 5 of structure 4, and front tractor may be. Upon even very slight movement of the steering wheel 152, therefore, the valve member of the valve 133 is moved sufiiciently from its neutral position to pressurize one or the other parts or sides of the cylinder 117 to initiate the pivotal movement of the front portion 5 of the structure 4 and the attached tractor about the vertical axis through the pivot pin 40 of the frame 4. Upon only slight movement of the steering Wheel 152 in either direction, the rotational movement of the front portion 5 of the frame 4 is translated to the lever 133 by means of the link 14 1 whereby to rotate the lever about its intermediate pivot point, even while the pivot itself is moving in the abovedescribed arcuate path and move the end 139 of the lever sutficiently to return the valve member of the valve 133 to its neutral position and thus to arrest the rotation movement of the front portion 5 of the structure 4 and the attached tractor. During greater movement of the steering wheel, the turning movement will prevent the valve member from returning to its neutral position until the move ment of the wheel has stopped. The present construction, therefore, stops rotation or turning of said front portion of the structure and attached front tractor at an angle of turn, from any steered condition of the tractor unit in which said valve member is in its neutral position, corresponding to the amount the steering wheel 152 has been turned.

The interconnecting means 3 of the tractor unit supports the front tractor 1 in a proper position so that the previously removed front wheel bolster of the tractor can easily with an ample amount of clearance be moved under the mounting plate or flange portion 169 of the steering pivot shaft of the tractor for mounting thereto by means of the usual four bolts preparatory to separation of the tractor from the structure 4 for independent use of the tractor. This supported position of the tractor, of course, also facilitates removal of the front wheel bolster thereof during formation of the tractor unit.

Should it be desired to operate one of the tractors independently of the unit for lighter farm or other Work, the front tractor 1 can be quickly disconnected from the unit after mounting of the front wheel bolster as above mentioned merely by pulling the front four quick detach

cotter elements

63 and 87 and knocking or pulling out the four

pins

62 and 76. Such disconnection only takes a few seconds and constitutes one of the important features of the present invention. The front tractor is, of course, readily reconnected by the reverse process.

For such independent use of the front tractor, the drawbar 105, which is the sole drawbar of the tractor unit, is very quickly disconnectable from the rear tractor by removing the two pins 106 and two nuts of the eyebolts of the axle carrier brackets 99 and reconnectable within the

pocket structures

46 and 50 and to the axle carrier brackets 68 of the front tractor by insertion of the same pins and threading on of the nuts of the eyebolts of the rear portions 70 of the axle carrier brackets 68. In order to obtain the proper level of the drawbar when mounted on the front tractor, the pins 173 of the latter are removed from the rear holes of the U-shaped members 108 and the braces 109 repinned in the forward holes 174 of said members.

Should it be desired to operate both tractors independently, the structure 4 can be quickly and easily removed from both of the tractors merely by withdrawing the four connecting pins on each of the tractors, namely 62, 76, 86, and 101, after first disconnecting the two attaching bolts between the

members

146 and 147 and the flange at the bottom of the steering pivot shaft 150 of the rear tractor and hydraulic lines and 161 from the front tractor. Prior to such removal of the structure 4, the front wheel bolster of the front tractor would be mounted in place and the rear tractor supported by suitable means as by a jack placed rearwardly of the crossmember 23. After such removal, the front wheel bolster of the rear tractor would be mounted in place while the rear tractor remained supported.

For connecting the structure 4 and formation of the tractor unit, the forward tractor 1 can be conveniently backed into proper spaced relation to the rear tractor 2 while the latter is supported after removal of the front wheel bolster thereof and the structure 4 conveniently and easily slipped into the stirrup or

pocket structures

45, 46, 47, and 48 and 49, 50, 51, and 52 as by the use of jacks and pinned. The unit is completed by reconnecting the pair of connecting bolts between the

members

146 and 147 and the flange of the steering pivot shaft 150 of the rear tractor and reconnection of fluid lines 160 and 161.

As previously indicated, the interconnecting means 3 of the tractor unit is rigid in the longitudinal vertical plane for withstanding bending moments resulting from its support of the tractors forwardly of the rear wheels thereof while it permits free pivotal movement in the horizontal plane and transverse vertical plane normal to the longitudinal vertical plane to provide for turning or steering of the tractor unit and also relative roll between the two tractors.

It is further pointed out that the structure 4 supports each of the tractors at a midpoint which most significantly relieves the tractor structures of all stresses in excess of those they are intended to receive in their normal use as individual tractors as a result of the removal of the front wheel bolsters and cantilevered arrangement of the tractors.

Also very significant, by having the rear tractor 2 supported at a midpoint with the forward portion thereof extending in unsupported, flexible cantilever fashion rather than being rigidly tied to the structure 4 at the front, said structure not only takes the excess bending moment above indicated but also substantially all of the torsional stress resulting from operating the tractor unit in a curved path or while making a turn. This torsional or twisting stress which is imposed on the structure 4 results from the bending moment previously mentioned being set up within said structure while the forward and

rear portions

5 and 6 thereof are disposed at an angle to each other due to the turning movement of the tractor unit, thus causing the vertex of the angle formed by such portions at the medial yoke and pin portion of the structure to swing in an arc to set up the twisting forces. The structure 4 therefore takes substantially all of the torsional or twisting stress rather than the tractor structure which is not designed and intended to withstand such stress and which would otherwise fail or be seriously damaged.

There is, of course, but a single operator of the tractor unit who sits on the rear tractor 2 and has other operating controls running to the forward tractor, but inasmuch as these controls do not form part of the present invention they are not disclosed.

Although it is clearly preferably to remove the front wheel bolster of the front tractor during formation of the tractor unit, the bolster may be left on the tractor, if desired, if sufficient clearance is provided between the wheels thereof and the ground to assure that the wheels are out of contact with the ground during operation of the unit. In this case, of course, the interconnecting means 3 would have to be formed so as to support the front of the forward tractor in a higher position to provide such clearance between the wheels and the ground.

Although one double-acting hydraulic cylinder has been disclosed as the motor means for producing pivotal movement between the forward and rearward portions of the structure 4', two single-acting cylinders may be employed on opposite sides of the tandem tractor unit, respectively, for instance, or other suitable motor means may be employed, if desired.

It should be understood that although the tandem tractor unit which has been illustrated and described has two tractors, such unit not necessarily limited to two tnactors. For example, the substructure of the interconnecting means could extend rearwardly under a third tractor from which the front wheel bolster has been removed, for instance, the structure being suitably articulated between the second and third tractors to permit moving of the tandem tnactor unit in curved paths as for turning.

While reference has been made to the tractor unit as operating over the ground, the same can, of course, operate on any suitable supporting surface, indoors as well as out, and accordingly, the word ground is used in the specification and appended claims as a convenient expression intended to cover any suitable supporting surface of tandem connected articles.

Although the foregoing portions of the specification have referred particularly to tandem connected tractors and the interconnecting means therefor, it is not intended necessarily to limit the invention to tractors inasmuch as the same is applicable to other vehicles, mobile equipment, and other articles and components for interconnection thereof in tandem so as to be movable along the ground as a unit.

It should be understood that such terms as horizontal and vertical appearing in the specification are merely relative to the position of the tandem tractor unit shown in the drawing, that is, when on perfectly level ground, and accordingly such terms in the appended claims are not to be construed in the absolute sense but rather as pertaining to the subject tandem units of the claims when on level ground.

Although a specific, preferred form of the invention has been disclosed, modifications and other forms are had in mind and accordingly, the invention should be limited only by the terms of the appended claims, liberally construed in the overall light of the invention in its various aspects.

What is claimed is:

1. A mobile unit comprising a pair of components each having ground-engaging support means movable along the ground and the center of gravity of each being longitudinally beyond said support means so that each unconnected to the other component would tip toward the ground, connecting means interconnecting the components in tandem so as to prevent the aforesaid tipping and provide for unitary longitudinal'movement of the components along the ground, said connecting means including a structure which is rigid in the longitudinal vertical plane and articulated at a longitudinal location for swinging movement between the two portions thereof adjacent the articulation in the horizontal plane, said-two portions of said structure being attached to the components respectively so as to permit relative swinging movement between the components solely at the location of articulation of said structure for permitting longitudinal movement of the unit along the ground selectively in straight and curved paths, said structure supporting each component longitudinally beyond said support means in the direction of the end of the component longitudinally between which and said support means the center of gravity of the component is located, actuating means comprising motor means connected to one of said portions, means operatively connecting said motor means to the other of said portions for causing swinging movement between said portions and consequently between said components in one direction upon movement of the second named connecting means in one direction and in the opposite direction upon movement of the second named connecting means in the opposite direction, means for conducting energy to the motor means, motor control means connected to said energy conducting means selectively operable for permitting passage of energy received by the control means to the motor'means through said energy conducting means for effecting movement of the second named connecting means and for preventing passage of energy beyond the control means for arresting swinging movement between said portions substantially maintaining the positions of said portions relative to each other after the arresting of the swinging movement between said portions, one of the components having steering control'means oper atively connected to the motor control means for operating the latter for producing said swinging movement be tween said portions.

2. The subject matter of claim 1, the end of one of the components between which end and said support means its center of gravity is located being the end closest to the other component in the connected condition of the components, the support afforded by said structure to said one component longitudinally beyond said support means being longitudinally removed from said end for at least reducing twisting forces in said one component during substantially longitudinal movement of the connected components along the ground in other than a straight path.

3. The subject matter of claim 1, each of said two portions of said structure being attached to its respective component by means comprising pin means, said structure being quickly and simply removable from the components when connected in tandem merely by removal of said pin means, said structure being easily connec'table to the components for connecting the components in tandem by the reverse pinning process.

4. A construction for tandemizing two vehicles with the vehicles facing in the same direction, each vehicle having rear axle housing means and rear ground-engaging support means, the construction comprising means for connecting the vehicles in tandem so that during movement along the ground they engage the ground solely through the rear support means thereof, the connecting means including a structure which is rigid in the longitudinal vertical plane and articulated at a longitudinal location for swinging movement between the twoportions thereof adjacent the articulation on opposite sides of the latter in the horizontal plane, said two portions of said structure being attached to the vehicles respectively so as to permit relative swinging movement between the vehicles solely at the location of articulation of said structure for permitting longitudinal movement of the tandemized vehicles selectively in straight and curved paths, said structure supporting each vehicle substantially forward of the rear axle housing means thereof, said forward portion supporting the front vehicle forward of its housing means at a single longitudinal location, sai'd rearward portion supporting the rear vehicle forward of its housing means at a single longitudinal location, said longitudinal location of support of each of the vehicles being intermediate the front end and housing means of the vehicles and longitudinally substantially removed from each, the connection between said two portions of said structure comprising a yoke on one of said portions, means on the other of said portions received within the yoke, and pin means extending between the yoke and said means received therewithin, theforw ard portion of said structure having a pair of laterally spaced forwardly extendingportions for passage under the rear axle housing'means of the front vehicle and providing support of the front vehicle forwardly of the rear 'axlefhousing means at opposite sides of the vehicles respectively, the rearward portion of said structure having a pair of rearw'ardly extending portions for passage under the rear vehicle which converge toward the front.

5. A construction for tandemizing two vehicles with the vehicles facing in the same direction, each vehicle having rear axle housing means and rear ground-engaging support means, the construction comprising means for connecting the vehicles in tandem so that during movement along the ground they engage the ground solely through the rear support means thereof, the connecting means including a structure which is rigid in the longitudinal vertical plane and articulated at a longitudinal location for swinging movement between the two portions thereof adjacent the articulation on opposite sides of the latter in the horizontal plane, said two portions of said structure being attached to the vehicles respectively so as to permit relative swinging movement between the vehicles solely at the location of articulation of said structure for permitting longitudinal movement of the tandemized vehicles selectively in straight and curved paths, said structure supporting each vehicle substantially forward of the rear axle housing means thereof, the means for connecting the vehicles in tandem including means for connecting the forward portion of said two portions to the rear axle housing means of the front vehicle, means connected to said forward portion for solely supporting, forward of said housing means of the front vehicle, the front vehicle on said structure at a longitudinal location which is intermediate the rear axle housing means and front end of the vehicle and substantially removed longitudinally from each, means for connecting the rearward portion of said two portions to the rear axle housing means of the rear vehicle, and means connected to said rearward portion for solely supporting, forward of said housing means of the rear vehicle, the rear vehicle on said structure at a longitudinal location which is intermediate said housing means and front end of the vehicle and substantially removed longitudinally from each, said means for connecting the forward portion to said housing means of the front vehicle comprising a pair of means for connection to said housing means of the front vehicle on opposite sides of the vehicle respectively each comprising a pair of wall means horizontally spaced apart at the lower termini part of which is below said housing means, said means connected to said forward portion for solely supporting the front vehicle comprising a pair of means for connection to the front vehicle on opposite sides of the vehicle respectively forward of said housing means thereof each comprising a pair of wall means horizontally spaced apart at the lower termini and interconnected above said termini, said forward portion including a pair of forwardly extending members for passing under said housing means of the front vehicle and for extending within the four pairs of wall means, at least a pair of pin means extending through the rear pairs of wall means respectively and the received members of said structure respectively for sole attachment of said structure thereto, at least a pair of pin means extending through the front pairs of wall means respectively below the received members of said structure respectively for sole retention of said structure within said means, the front vehicle and connected means being quickly and simply removable from said structure and attached rear vehicle when the vehicles are tandemized for independent use merely by removal of said pins, the front vehicle and connected means being easily connectable to the structure and attached rear vehicle by the reverse pinning process.

6. The subject matter of claim 5, said means for connecting the rearward portion to said housing means of the rear vehicle comprising a pair of means for connection to said housing means of the rear vehicle on opposite sides of the vehicle respectively each comprising a pair of wall means horizontally spaced apart at the lower termini, said means connected to said rearward portion for solely supporting the rear vehicle comprising a pair of means for connection to the rear vehicle on opposite sides of the vehicle respectively forward of said housing means thereof each comprising a pair of wall means horizontally spaced apart at the lower termini and interconnected above said termini, said rearward portion including a pair of forwardly extending members for extending within the four pairs of wall means, at least a pair of pin means extending through the rear pairs of wall means respectively and the received members of said structure respectively for sole attachment of said structure thereto, at least a pair of pin means extending through the front pairs of Wall means respectively below the received members of said structure respectively for sole retention of said structure within said means, said structure being quickly and simply removable from both vehicles for independent use of the vehicles merely by removal of said pins, said structure being easily connectable to the vehicles by the reverse pinning process.

7. A construction for tandemizing two vehicles with the vehicles facing in the same direction and for turning the front vehicle for steering the tandemized vehicles, the vehicles each having rear axle housing means, rear groundengaging support means, and normally prior to tandemizing a front bolster with attached ground-engaging support means and from at least the rear vehicle of which the front bolster and attached support means are removed in the tandemized condition of the vehicles, the rear vehicle having limitedly rotatable means at least near the front thereof for turning the front bolster normally attached to the means prior to tandemizing for steering the vehicle and a steering wheel operatively connected to the rotatable means for rotation of the latter in either direction, the construction comprising means for connecting the vehicles in tandem so that the latter at least most of the time during movement along the ground engage the ground solely through the rear support means thereof, the connecting means comprising a structure which is substantially rigid substantially in the longitudinal vertical plane and articulated at a longitudinal location for swinging movement between the two portions thereof adjacent the articulation on opposite sides of the latter substantially in the horizontal plane, said two portions of said structure being attached to the vehicles respectively, when the latter are tandemized, so as to permit relative swinging movcmerit between the vehicles solely at the location of articulation of said structure for permitting substantially longitudinal movement of the tandemized vehicles selectively in straight and curved paths, said structure supporting each vehicle, when the vehicles are tandemized, substantially forward of the rear axle housing means thereof, the construction including actuating means comprising motor means connected to one of said portions of said structure, means operatively connecting the motor means to the other of said portions of said structure effective to cause swinging movement of the forward portion of said two portions of said structure relative to the rearward portion of said two portions of said structure and consequently of the front vehicle relative to the rear vehicle of the tandemized vehicles, at least during substantially longitudinal movement of the tandemized vehicles, in one direction upon movement of at least part of the second named connecting means in one direction and in the opposite direction upon movement of at least part of the latter connecting means in the opposite direction, means for conducting energy to the motor means for operation of the latter, motor control means connected to said means for conducting energy selectively operable so as to permit passage of energy received by the control means to at least part of the motor means through part of said means for conducting energy for elfecting movement of at least part of the second named connecting means in said one direction, for effecting said swinging movement of said forward portion relative to said rearward portion of said structure in said one direction, so as to permit passage of energy received by the control means to at least part of the motor means through part of said means for conducting energy for effecting movement of at least part of the second named connecting means in said opposite direction for effecting said swinging movement of said forward portion relative to said rearward portion of said structure in said opposite direction, and so as to prevent passage of energy beyond the control means for arresting swinging movement of said forward portion relative to said rearward portion of said structure during swinging; movement of the same in either direction and for substantially maintaining the position of said forward portion relative to said' rearward portion of said structure after the arresting of the swinging movement of said forward portion, motor control means operatingmeans relatively nonrotatably connectible to said rotatable means of the rear vehicle and operatively connected to the motor control means effective to operate the latter so as to produce said swinging movement of said forward portion relative to said rearward portion of said structure in said one direction upon appreciable turning of the steering wheel of the rear vehicle of the tandemized vehicles in one direction and so as to produce said swinging movement of said forward portion relative to said rearward portion of said structure in said opposite direction upon appreciable turning of said steering wheel in the other direction, the motor control means being connected to said rearward portion of said structure, and means connecting said forward portion of said structure and the motor control means operating means effective through the latter to operate the motor control means so as to arrest swinging movement of said forward portion relative to said rearward portion of said structure in either direction and prevent further swinging movement thereof until further operation of the motor control means upon the swinging movement bringing said forward portion of said structure to a position relative to said rearward portion of said structure substantially corresponding to the position in which said steering wheel has been placed by the operator of the tandemized vehicles.

8. The subject matter of claim 7, the support afforded by said structure to the rear vehicle forward of said housing means thereof being at least substantially to the rear of the front end of the vehicle for at least substantially reducing twisting forces in the rear vehicle during movement of the tandemized vehicles in other than a straight path.

9. A construction for tandemizing two vehicles with the vehicles facing in the same direction and for turning the front vehicle for steering the tandemized vehicles, the vehicles each having rear axle housing means, rear groundengaging support means, and normally prior to tandemizing a front bolster with attached ground-engaging support means and from at least the rear vehicle of which the front bolster and attached support means are removed in the tandemized condition of the vehicles, the rear vehicle having limitedly rotatable means at least near the front thereof for turning the front bolster normally attached to the means prior to tandemizing for steering the vehicle and a steering wheel operatively connected to the rotatable means for rotation of the latter in either direction, the construction comprising means for connecting the vehicles in tandem so that the latter at least most of the time during movement along the ground engage the ground solely through the rear support means thereof, the connecting means comprising a structure which is substantially rigid substantially in the longitudinal vertical plane and articulated at a longitudinal location for swinging movement between the two portions thereof adjacent the articulation on opposite sides of the latter substantially in the horizontal plane, said two portions of said structure being attached to the vehicles respectively, when the latter are tandemized, so as to permit relative swinging movement between the vehicles solely at the location of articulation of said structure for permitting substantially longitudinal movement of the tandemized vehicles selectively in straight and curved paths, said structure supporting each vehicle, when the vehicles are tandemized, substantially forward of the rear axle housing means thereof, the construction including actuating means commotor means connected to one of said portions of said structure, means operatively connecting the motor means to the other of said portions of said structure effective to cause swinging movement ofthe forward portion of said two portions of said structure relative to the rearward portion of said two portions of said structure and consequently of the front vehicle relative to the rear vehicle of the tandemized vehicles, at least during substantially longitudinal movement of the tandemized vehicles, in one direction upon operation of the motor means in one direction and in the opposite direction upon operation of the motor means in the opposite direction, means for conducting energy to the motor means for operation of the latter, motor control means connected to said means for conducting energy selectively operable so as to permit passage of energy received by the control eans to the motor means through part of said means for conducting energy for opera-ting the motor means in said one direction for said swinging movement of said forward portion relative to said rearward portion of said structure in said one direction, so as to permit passage of energy received by the control means to the motor means through part of said means for conducting energy for operating the motor means in said opposite direction for said swinging movement of said forward portion relative to said rearward portion of said structure in said opposite direction, and so as to prevent passage of energy beyond the control means for arresting operation of the motor means in either direction and consequently swinging movement of said forward portion relative to said rearward portion of said structure during swinging movement of the same in either direction and for substantially maintaining the position of said forward portion relative to said rearward portion of said structure after the arresting of the swinging movement of said forward portion, motor control means operating means relatively nonrotatably connectible to said rotatable means of the rear vehicle and operatively connected to the motor control means effective to operate the latter so as to produce said swinging movement of said forward portion relative to said rearward portion of said structure in said one direction upon appreciable turning of the steering wheel of the rear vehicle of the tandemized vehicles in one direction and .so as to produce said swinging movement of said forward portion relative to said rearward portion of said structure in said opposite direction upon appreciable turning of said steering wheel in the other direction, the motor control means being connected to said rearward portion of said structure, and means connecting said forward portion Olf said structure and the motor control means operati-ng means effective through the latter to operate the motor control means so as to arrest swinging movement of said forward portion relative to said rearward portion of said structure in either direction and prevent further swinging movement thereof until further operation of the motor control means of said structure to a position relative to said rearward portion of said structure substantially corresponding to the position in which said steering wheel has been placed by the operator of the tandemized vehicles.

prising 10. In combination with a pair of tractors from which the front wheel bolsters have been removed; connecting means for hitching the tractors in tandem so that steering may be accomplished from the rear tractor, said connecting means comprising a forward portion supporting the front tractor in proximity to its center of gravity, a rear portion supporting the rear tractor in proximity to its center of gravity, and an intermediate portion connected to the front portion pivotally in the vertical transverse plane and connected to the rear portion pivotally in the horizontal plane; power means mounted on the rear portion and connected with the intermediate portion for pivoting the intermediate portion in the horizontal plane; control means responsive to steering of the rear tractor for engaging the power means; and followup means re- References Cited in the file of this patent UNITED STATES PATENTS Wells June 28, 1932 Wright Dec. 20, 1955 Gaspardo Aug. 26, 1958 ROCklWCll May 5, 1959 Toth July 28, 1959 Gar-man Nov. 29, 1960

Claims

1. A MOBILE UNIT COMPRISING A PAIR OF COMPONENTS EACH HAVING GROUND-ENGAGING SUPPORT MEANS MOVABLE ALONG THE GROUND AND THE CENTER OF GRAVITY OF EACH BEING LONGITUDINALLY BEYOND SAID SUPPORT MEANS SO THAT EACH UNCONNECTED TO THE OTHER COMPONENT WOULD TIP TOWARD THE GROUND, CONNECTING MEANS INTERCONNECTING THE COMPONENTS IN TANDEM SO AS TO PREVENT THE AFORESAID TIPPING AND PROVIDE FOR UNITARY LONGITUDINAL MOVEMENT OF THE COMPONENTS ALONG THE GROUND, SAID CONNECTING MEANS INCLUDING A STRUCTURE WHICH IS RIGID IN THE LONGITUDINAL VERTICAL PLANE AND ARTICULATED AT A LONGITUDINAL LOCATION FOR SWINGING MOVEMENT BETWEEN THE TWO PORTIONS THEREOF ADJACENT THE ARTICULATION IN THE HORIZONTAL PLANE, SAID TWO PORTIONS OF SAID STRUCTURE BEING ATTACHED TO THE COMPONENTS RESPECTIVELY SO AS TO PERMIT RELATIVE SWINGING MOVEMENT BETWEEN THE COMPONENTS SOLELY AT THE LOCATION OF ARTICULATION OF SAID STRUCTURE FOR PERMITTING LONGITUDINAL MOVEMENT OF THE UNIT ALONG THE GROUND SELECTIVELY IN STRAIGHT AND CURVED PATHS, SAID STRUCTURE SUPPORTING EACH COMPONENT LONGITUDINALLY BEYOND SAID SUPPORT MEANS IN THE DIRECTION OF THE END OF THE COMPONENT LONGITUDINALLY BETWEEN WHICH AND SAID SUPPORT MEANS THE CENTER OF GRAVITY OF THE COMPONENT IS LOCATED, ACTUATING MEANS COMPRISING MOTOR MEANS