US2202068A - Directional control means for movable trucks and the like - Google Patents

Description

May 28, 1940. 1. F. SCHRECK DIRECTIONAL 'CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6, 1939 4 Sheets-Sheet 1 i H I l ailrlillllllllillfli ,IDIIIIWH INVEN fizwlll z FJZfiYJeG/H y 1940- I. F. SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6, 1939 4 Sheets-Sheet 2 Flag, 3

INVENTO P HfTOR/VEY y 28, 1940- I. F SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6, 1939 4 SheetsSheet 5 y 28, 1940- F. SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6, 1939 4 Sheets-Sheet 4 INVENTGR [WWI z 2. 15 cZ/zne. a/C

L WITNE MM Patented May 28, 1940 UNITED STATES DIRECTTONAL CONTROL MEANS FOR MOV- ABLE TRUCKS AND' THE LIKE Irvin F. Schreck, Cleveland, Ohio, assignor to Bond Foundry & Machine Company, Manheim, Pa, a corporation of Pennsylvania Application June 6, 1939, Serial No. 277,583

16 Claims.

This invention relates to movable trucks, racks, and similar vehicles for transporting articles over short distances such as about a shop or mill and is particularly directed to the provision, in a truck or the like having swivel casters, of means including a supplementary non-swiveling caster, preferably adjacent each end of the truck, to facilitate control of the direction of its movement, especially when it is being pushed from the rear.

When all casters on a truck of this general character are free to swivel it is difficult to guide it, as the swivel casters move about their swivel axes in directions other than parallel to the desired path of travel of the truck, and my invention therefore contemplates bringing a supplementary caster at the leading end of the truck into engagement with the floor to facilitate accurate control of the direction of travel of the truck by inducing the swivel casters to remain'in alignment parallel to said desired path of travel, especially when the truck is manipulated from its opposite end. The supplementary casters are rotatable in engagement with the floor on axes normal to the longitudinal center line of the truck and are incapable of swiveling as the load supporting casters do, as I have found greatly enhanced control of the truck is attained when the load supporting casters do not participate in the determination of the direction of its travel but are automatically constrained to follow the desired course by the action of one of the supplementary casters.

Moreover, the invention in certain of its embodiments also contemplates automatically bringing a direction-controlling supplementary caster into contact with the floor upon manipulation of a folding push bar at the end of the truck which when raised to operative position affords a convenient hand grip for the operator to facilitate moving and guiding the truck. Additionally, some embodiments of the invention include means for yieldingly maintaining the supplementary nonswiveling caster in engagement with the floor during movement of the truck whereby such caster is caused to closely follow the floor and remain in contact with it even when irregularities are encountered which might otherwise cause it to either assume an excessive proportion of the truck load or else, as when passing over a depression in the floor, clear the floor entirely and thus become inoperative to control the swivel casters. It is therefore a principal object of the invention to provide in a truck or similar vehicle having swivel casters, a supplementary non-swiveling castenpreferably one adjacent each end. of the truck, adapted to be brought into engagement with the floor for rotation only in a plane parallel to thesides of the truck to thereby facilitate control of its direction of movement over the floor.

A further object is to provide automatic mech- .5 anism for moving a non-swiveling caster into yielding engagement with the floor preparatory to manipulation of the truck to facilitate control of the direction of movement of the latter and for thereafter retracting said caster from floor en- ,g gagement to permit the truck to be moved sideWise on its swivel casters in a direction transversely of the plane of rotation of the non-swiveling caster wheel.

Another object of the invention in certain of its embodiments is to provide, in a truck having swiveling load supporting casters, a supplementary non-swiveling caster adjacent each of its ends and means interconnected with such supplementary casters whereby they may selectively be brought into engagement with the door by manipulation of operating means adjacent the respectively opposite ends of the truck to facilitate guiding it as it is moved along the floor.

' Other objects, purposes and advantages of the invention will hereafter more fully appear or be understood from the following description of certain illustrative embodiments thereof shown in the accompanying drawings, and While in general its objects and. purposes are somewhat analogous to those of the caster control means for movable trucks and the like forming the subject of U. S. Letters Patent of Irvin F. Schreck and Chester S. Mann No. 2,132,973, issued October 11, 1938, the present invention constitutes improvement thereon in certain respects.

In the drawings, Fig. 1 is a fragmentary side elevation, partly in vertical section, of a truck equipped with one embodiment of the invention shown in position for operation of the truck from the left hand end in said figure;

Fig. 2 is a' bottom plan View thereof and- Fig'. 3 is an enlarged end view of the truck with the control mechanism in neutral or inoperative position, other positions of certain parts being indicated by broken lines. 1

Fig. 4 is a fragmentary view generally corresponding to a portion of Fig. 3 but showing a modified embodiment of the invention adapted for foot operation;

Fig. 5 is a fragmentary top plan view of the mechanism shown in Fig. 4;

. Fig. 6 is a fragmentary detail corresponding to Fig. 4 but showing more clearly certain parts in positions which are indicated therein only in broken lines and Fig. 7 is a fragmentary staggered vertical section on the line '|'I in Fig. 4.

Fig. 8 is a fragmentary end view corresponding generally to Fig. 3 but showing another modification of the invention adapted for foot operation;

Fig. 9 is an enlarged fragmentary top plan view thereof and Fig. 10 is a fragmentary side elevation of the control mechanism with a portion of the truck body in vertical section.

Fig. 11 is a fragmentary side elevation, also enlarged, of a truck equipped with another embodiment of the invention;

Fig. 12 is a fragmentary top plan view of mechanism shown in Fig. 11 removed from the truck and Fig. 13 is an end View thereof partly in vertical section;

Figs. 14 and 15 are respectively a fragmentary side elevation and fragmentary bottom plan View generally corresponding to Figs. 1 and 2 but on a smaller scale showing still another embodiment of the invention.

In the several figures like reference numerals are used to designate the same parts, those performing the same or substantially similar functions in the several embodiments of the invention illustrated being distinguished by alphabetical exponents appended to their respective designating numerals. 7

Referring first more or less generally to the drawings the truck T, the specific details of construction of which are not material, is merely typical of any truck or other vehicle adapted to be supported from swivel casters and may be provided with two pairs of such casters C, C respectively located adjacent its ends. In accordance with the invention supplementary casters generally designated I I are disposed at opposite ends of the truck T substantially on its center line and generally U-shaped push bars 2, 2' are hinged to brackets 3, 3, l, 4 on the ends of the truck body whereby either bar when raised affords a hand grip to facilitate operation of the truck. In some embodiments of the invention shown in the drawings chains 5, 5 interconnect the push bars respectively with the subjacent supplementary casters and the latter are interconnected by a rod Il' whereby they are simultaneously operated to facilitate the guiding and control of the truck when either push bar is raised preparatory to moving it.

As the supplementary casters I, i at the opposite ends of the truck are substantially identical in structure and operation in each embodiment of the invention, specific description of one of them in each case will be understood as applying also to the other at the opposite end.

Thus the caster Ia at the right hand end of the truck shown in Figs. 1, 2 and 3, which assists the guiding and control of the truck Ta .when it is being operated through the instrumentality of the push bar 2a at its left hand end in said figures comprises a base plate 6a secured to the truck bottom through the cooperation of an integral upstanding flange Ia fitting over the adjacent edge of a corner iron t forming a part of the truck frame and a clamp 8 held to the base plate by bolts 9 and nuts Ill and embracing the horizontal flange of the corner iron. The supplementary casters thus may readily be attached to conventional trucks whether initially constructed for their reception or not.

The plate 6a includes an integral downwardly depending ear Ma substantially aligned vertically with the flange Ia and another ear I50 parallel thereto adjacent the opposite edge of the base plate. These ears are provided with aligned holes IBa each having at its lower part flat faces intersecting at an inverted angle forming a notch the sides of which are tangent to the upper circular part of the hole, as best shown in Fig. 3. A rod Ila extends through these holes in the base plate ears of both casters and interconnects the latter beneath the truck. Between the base plate ears the rod Ila carries a sleeve I8a secured to the rod by a set screw Ma, and an integral downwardly and laterally projecting arm 20a on the sleeve supports an axle 2Ia which extends laterally outwardly for the reception of the supplementary caster wheel 22a rotatable on the axle but restrained by the rigid attachment of the axle to the arm from swiveling about a vertical axis as do the casters C.

The arm 20a is formed with an integral projection 23a and the chain 5a suspended from the push bar 2a is attached to this arm by a cap screw 24a, the chain thus interconnecting the caster and push bar in such a way that when the latter is raised an upward pull is exerted upon the adjacent supplementary caster arm 2 Ia causing the latter to turn the rod Ila generally about its axis; due to the loose fit of the rod in the holes Ifia the first movement of the arm, however, causes the rod to ride out of the notches in these holes and move upwardly into their circular parts,

Thus as either push bar is raised preparatory to its use as a handle for guiding and moving the truck the adjacent chain automatically actuates the supplementary guiding caster mechanism without attention from the operator to facilitate the guiding and control of the truck as will now be more fully described.

For example, when the mechanism is in neutral position as indicated in full lines in Fig. 3 and the push bars at both ends of the truck are lowered as when the truck is merely standing unattended, the casters Ia and Hz and their associated mechanisms are substantially in static balance and their interconnecting rod I'Ia rests in the notches at the bottoms of the holes I6a with its lower faces forming angles of substantially 45 with the vertical and horizontal. In this position the arms 20a, 20a hold both supplementary caster wheels elevated above the floor and above the plane of the swivel casters C, C, and the truck may be pushed in any direction without the aid of the supplementary casters so long as the push bars remain lowered.

When the truck is to be pushed for an appreciable distance, however, it is usually most convenient to utilize one of the push bars and raising either of them for this purpose brings into play the supplementary casters to facilitate guiding and control of the direction of travel. Thus when the push bar 2a is raised to operative position as shown in Figs. 1 and 2 it acts through the chain 5a to raise the subjacent supplementary caster Ia and bring the rod Il'a out of the notches in the holes I6a to rotate it about its longitudinal axis in a counterclockwise direction as viewed in Fig. 3. The caster Ia under these conditions moves to its upper dotted line position indicated in said figure while the supplementary caster Ia at the opposite end of the rod and adjacent the now leading end of the truck, being disposed on the opposite side of the rod from 75 the caster la, is brought by the movement of the rod into engagement with the floor, as indicated by its lower dotted line position in Fig. 3. Both operating chains 5a, 5a are desirably so adjusted that the adjacent supplementary caster is moved through a somewhat wider arc than one just sufiicient to bring the supplementary caster at the opposite end of the truck into contact with the floor when the push bar is lifted to operative position, and the rod Ha is therefore placed under torsional tension so that its inherent torsional elasticity yieldingly maintains such supplementary caster in intimate engagement with the floor as long as the push bar remains elevated. Thus throughout the time the latter is being utilized in the normal way for operating the truck the supplementary caster is caused to closely and yieldingly follow any irregularities in the floor rather than ride over depressions without touching them or partially lift the truck upon encountering an obstruction. The torsional yieldability of the rod moreover absorbs vibration and slight movements of the caster and prevents their transmission to the hands of the operator, and/or oscillation of the push bar on its hinges during operation of the truck, while the firmness with which the caster is maintained in contact with the floor, combined with its inability to rotate in any plane other than one parallel to the center line of the truck, tends to restrain the truck against movement other than in a plane parallel with such center line except when positively directed in a difierent path by the operator. The usual difficulties in directing swivel caster trucks, which have arisen from absence of adequate control of the planes in which the caster wheels rotate are thereby eliminated and the ease and convenience with which the truck can be guided in a desired direction greatly enhanced.

The push bar, when released, again folds against the truck end and the consequent relaxation of the tension on the adjacent chain enables the rod Ila to return to its notches in the holes l6a and thereby restore the supplementary casters to balanced position with both wheels elevated above, and therefore out of engagement with, the floor. The notches, moreover, tend to restrain the rod from turning about its axis and keep both wheels retracted from the floor even when the truck is moved over a rough surface as an ordinary swivel caster truck so that it may be pushed sidewise, or in any other direction, without the aid of the push bars, and the supplementary casters then do not participate in or interfere with the direction of movement of the swivel casters C, C in any way.

In the embodiment of the invention shown in Figs. 4-7 inclusive the supplementary casters lb, 1'!) and certain associated parts are substantially the same as in that just described but somewhat different mechanism is utilized for operating them. The supplementary casters lb, l'b in these figures are operated by chains at 5b, 5'?) at the ends of the truck but these chains, instead of being connected with push bars for automatic action upon manipulation of such bars, are connected with mechanism arranged for foot operation independently of any push bar or other guiding means with which the truck may be equipped. The supplementary caster at either end of the truck is thus brought into play by operation of foot actuated mechanism disposed at its opposite end and may be released in a like manner when, for example, the truck is to be pushed sidewise.

The mechanism controlling the operation of the supplementary casters lb, l'b is supported from an integral specially formed part of the caster base plate 6b which is thus provided with an overhanging web 30b defining with the end of the base plate an inverted channel 3| b withinv which the foot actuated levers are arranged for pivotal movement in a vertical plane parallel to the adjacent end of the truck. A main actuating lever 32b is thus pivotally supported on a pin 33b extending across the channel and threaded into the base plate and is provided with an outwardly projecting foot pedal 34b by whichit is operated. On its opposite end this lever has an integral projection 35b adapted to receive a cap screw 35b whereby the chain 5b is attached to the lever, the opposite end of this chain being connected to the projection 23'b on the arm 20'?) of the adjacent supplementary caster lb.

Thus when the foot pedal 34b is depressedthe chain is raised, operating the supplementary casters lb, Ib and associated mechanism in the same way that the casters la, la are operated by raising of the push bars in Figs. 1-3 inclusive. Means are also provided for releasably locking this mechanism in operative position to eliminate the necessity for attention of the operator during movement of the truck, such means comprising a latch lever 37b pivoted on a pin 38b spanning the channel 3Ib and threaded into the base plate. The end of this lever nearest the main lever is adapted to fall by gravity into a notch ltlb formed in the upper edge of the latter when the notch moves into position to receive it upon movement of the main lever to operate the supplementary casters and the latch lever thus automatically holds the main lever looked after the foot is removed from the pedal 33b; the supplementary caster lb at the opposite end of the truck is consequently held in engagement with the floor to assist in guiding the truck until the latch lever is subsequently operated to release the main lever, the latch lever having for this purpose a foot actuated operating pedal Mb projecting oppositely with respect to its pivot from the main lever and operable to release the latter to permit the supplementary casters to return to neutral position.

Thus with regard to the guiding and controlling iunction of the supplementary casters this embodiment of the invention operates similarly to the one first described, the independently operable levers provided for bringing them into play being preferred in some instances, as in trucks not equipped with push bars or comparable guiding handles, or when it is not desired to have the supplementary casters operate automatically. It will of course be understood that the latch lever 37?) rests against the main lever 32b Without engaging in the notch Mb both when the mechanism is in neutral position and when the main lever 32'!) and associated actuating mechanism at the opposite end of the truck has been operated to bring the supplementary caster lb into engagement with the floor, and that when the entire mechanism is in neutral or inoperative ment of the invention shown in Figs. 1-3.

Of course, after being so actuated, either main lever may readily be released by moving the adjacent latch lever by foot pressure on its pedal to withdraw its end from the notch in the main lever and allow the rod ilb to return to its notches in the holes I61: and hold the casters in neutral position.

Figs. 8-10 inclusive illustrate other mechanism for actuating supplementary casters lc, lc corresponding to those shown in the previous figures, its operation being somewhat similar to that of the mechanism shown in Figs. 4-7. Instead of including means for lifting one supplementary caster to turn the caster connecting rod and bring the supplementary caster at the opposite end of the truck into engagement with the floor, however, in this embodiment of the invention means are provided for directly actuating the rod ilc which is therefore extended an appreciable distance beyond the ends of the truck to facilitate their connection therewith. Thus a main actuating lever 320 has a square hole which receives the adjacent end of the rod and is secured to it by a set screw 42c whereby the shaft may be turned (clockwise in Fig. 8) by foot pressure on an integral pedal 3 30 formed on this lever to operate the shaft in substantially the same manner as the corresponding rod in the preceding figures is operated by raising one supplementary caster to bring the supplementary caster [0 at the opposite end of the truck into yielding engagement with the floor. Means are also here provided for releasably locking the main lever in operative position comprising a foot actuated latch lever 3'lc pivoted to the main lever 320 on a pin 380. The latch lever extends through a slot in the main lever 32c and has an integral pedal Me projecting laterally above the upper surface of the main lever oppositely from the pedal 34c thereon. The downwardly projecting lower end of the latch lever beneath the main lever is curved inwardly toward the truck and forms a detent 43c adapted to engage ratchet teeth 440 on the lower edge of the ear l tc of the adjacent supplementary caster base plate, the latch lever being urged about its pivot 380 in a direction to maintain this detent in engagement with the teeth by a spring 450 interposed between the pedal 4 I0 and an abutment lfic integral with and projecting adjacent this pedal from the main lever 320. Thus when the latter is depressed to operate the rod lie the detent engages in a tooth 44c and automatically holds the main lever depressed until released by disengagement of the detent from the ratchet teeth upon foot operation of the latch lever by its pedal 4 l c.

The embodiment of the invention shown in Figs. 11-13 inclusive comprises supplementary casters Id, I'd which are of different construction from those heretofore described, and while adapted to be operated by push bars similar to those in Figs. 1-3 or other suitable mechanism, the operating mechanism employed is largely a matter of choice and chains 5d, 5d in the drawings therefore merely illustrate the manner in which connection of such operating mechanism with the casters may be effected.

The supplementary casters ld, l'cl comprise caster wheels 2201, 22d adapted for vertical movement relatively to the truck as distinguished from the generally arcuate movement of the supplementary caster wheels heretofore described and the wheels 22d, 22d may therefore be provided with fiat treads instead of the curved treads utilized on the latter to facilitate positive engagement with the floor during oscillation caused by irregularities therein. In this embodiment of the invention the caster wheels 22d, 22d are moved vertically by cam action and are brought into positive engagement with the floor and retained therein through manipulation of their operating means in such a way as to inhibit their yielding movement upon encountering irregularities in the floor.

The supplementary caster ld thus includes a base plate 6d secured to the bottom of the truck and having a pair of integral downwardly depending arms 4703 which support a transverse shaft 48d to which an eccentric cam 39d rotatable with the shaft is secured by a set screw 50d for controlling the position of the caster wheel. The shaft 38d is operated by a crank arm 5ld secured to one of its ends and a collar 52d at its other end cooperates with the crank arm to retain the shaft in proper position longitudinally while an operating chain 5d and rod lld interconnecting the casters ld, I'd are fastened to the projecting end of the crank arm by a nut ingly resist its downward movement under the influence of the cam 49d which operates to depress the blooks through an actuating yoke 59d formed by slidable plungers 60d extending through holes in the base plate arms and an interconnecting rigid cross bar 86d engaged by the cam face. Thus when the cam 39d is moved by operation of the crank arm d clockwise to the position shown in Fig, 11 the caster wheel 22d is depressed against the force of the springs 58d into floor engaging position, and when the cam moves or is free to move in the opposite direction the springs raise the wheel from the floor.

The movements of the cams 49d and 49d of both casters are controlled simultaneously through interconnection of their crank arms 51d, 5! 'd by the rigid rod lid, and connections of the latter with the chains 5'61, 5d respectively at the ends of the truck therefore operate both casters when either chain is pulled, as by raising a superjacent push bar (not shown) from. which the chain passes to connection with the casters over a sheave (62d or 62d) at a lower corner of the truck. Thus the cam of the supplementary caster at the end of the truck opposite that at which the push bar or the like being operated is posi tioned is rotated to depress the corresponding caster wheel while the wheel of the other caster simultaneously rises above its neutral position under the influence of its springs. The cams and crank arms are desirably so adjusted and arranged that neither cam. ever attains full deadcenter position and the force of the springs of the depressed caster therefore is sufficient to return the entire supplementary caster mechanism to neutral position when the chain is released, its return to this position being enhanced somewhat by the weight of the rod llcZ inducing the springs 58d of both casters to become mutually balanced.

The embodiment of the invention shown in Figs. 13 and 14 is adapted for the same purposes as the others and due to its greater simplicity and relatively inexpensive construction it may sometimes be preferred.

It comprises a longitudinally extending bifurcated rod I'le pivoted at its center on a bracket 646 depending from the bottom of the truck substantially at the intersection of its longitudinal and transverse center lines. The rod extends slightly beyond the ends of the truck and is connected at its ends through chains-5e, 5'e respectively with push bars 2e, 2'e. Near its ends the rod supports transversely disposed axles 2|, 2le on which supplementary caster wheels 22c, 22'e can rotate in a plane parallel to the longitudinal center line of the truck and be brought into engagement with the floor by appropriate movement of the rod on its pivot induced by operation of the push bars 2e, Ze, through the chains 5e, 5e, to assist in guiding the truck in the same manner as those in the embodiments of the invention already described. As their structure and operation will be apparent from the foregoing more specific reference thereto would be superfluous.

While I have herein illustrated and described with considerable particularity several embodiments of my invention operating in accordance with the same general principles and adapted to facilitate guiding and control of a truck equipped with swivel casters, it will be apparent that they embody many differences in details of construction and specific features of their operation and that numerous other embodiments thereof op erating according to these general principles may be devised; it is therefore to be understood that I do not desire or intend to restrict or confine my invention in any way to any or all of the embodiments to which reference hasherein been made or to any specific details of the construc-' tion of any embodiment thereof as changes and I modifications in the form, structure, and arrangement of the several parts, in the operating mechanisms utilized therefor, and in the mode of operation employed will readily occur to those skilled in the art and may be made if desired without departing from the spirit and scope 'of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect by Letters Patent of the United States:

1. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, supplementary casters respectively adjacent the ends of the truck, and means operable from the ends of the truck for selectively bringing the wheel of one supplementary caster substantially into said horizontal plane while maintaining the other supplementary caster retracted from said plane.

2. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, supplementary, non-swiveling casters adjacent the ends of the truck having wheels movable relatively thereto, and means adjacent each end of the truck operable to bring the wheel of the supplementary caster adjacent the opposite end thereof substantially into said plane While maintaining the other supplementary caster wheel retracted therefrom.

3. In combination with a truck or the like in cluding a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane; supplementary non-swiveling casters having movable wheels adjacent the ends of the truck, means adjacent each end of the truck operable to move the wheel of the adjacent supplementary caster relatively to said plane, and means interconnecting the supplementary casters operable on movement of one supplementary caster wheel in one direction relatively to said plane to move the other such wheel in the opposite direction.

4. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, supplementary non-swiveling casters having movable wheels adjacent the ends of the truck, a rod extending longitudinally beneath the truck interconnecting the supplementary casters, and means adjacent the ends of the truck respectively operable to move the rod in opposite directions to thereby move a .corresponding supplementary caster wheel substan tially into said plane.

5. In combination with a truck or the like including a plurality of swivel castershaving caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, means interconnecting the supplementary casters operable when the wheel of one is moved relatively to said plane to move the wheel of the other in the opposite direction relatively thereto, and means interconnected with each supplementary caster for moving its wheel relatively to said plane.

6. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a movable rod interconnecting said casters, and actuating means adjacent each end of the truck for moving the wheel of the adjacent supplementary caster in one direction relatively to said plane to thereby operate said rod to move the wheel of the other supplementary caster in the opposite direction relatively to said plane.

'7. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a

rod extending between the supplementary casters supporting them for movement substantially about its axis, and means adjacent each end of the truck respectively operable to rotate the rod to thereby move the supplementary caster adjacent the opposite end of the truck substantially into said plane.

8. In combination with a truck or the like including a plurality of swivel casters having caster wheelsdisposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a rod, interconnecting the supplementary casters, means carried by the rod supporting the su plementary caster wheels for movement substantially about the rod axis, means adjacent each end of the truck operable to move the wheel of the adjacent supplementary caster about said axis in one direction relatively to said plane to thereby rotate the rod to move the wheel of the other supplementary caster in substantially the opposite direction relatively to said plane.

9. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a rod interconnecting the supplementary casters, means carried by the rod supporting the supplementary caster wheels for movement sub stantially about the rod axis, and actuating means for each supplementary caster operable to move the wheel thereof away from said plane to thereby rotate the rod and move the wheel of the other supplementary caster yieldingly into said plane.

10. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a rod interconnecting the supplementary casters, means carried by the rod supporting the supplementary caster Wheels for movement substantially about the rod axis, a push bar pivoted to each end of the truck, and means interconnecting each push bar with the subjacent supplementary caster wheel supporting means operable on movement of the push bar in one direction to move the wheel of said supplementary caster in a corresponding direction relatively to said plane to thereby rotate the rod about its axis to move the wheel of the other supplementary caster in the opposite direction relatively to said plane.

11. In combination with a truck or the like including a pliu'ality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a rod interconnecting the supplementary casters, means carried by the rod supporting the supplementary caster wheels for movement substan tially about the rod axis, a push bar pivoted to each end of the truck, and means interconnecting each push bar with the rod operable when the push bar is moved to operative position torotate the rod and thereby move the wheel of the supplementary caster adjacent the opposite end of the truck yieldingly into said plane.

12. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, a movable rod extending longitudinally of the truck interconnecting the supplementary casters, and means carried by each supplementary caster operable to rotate the rod to thereby move the wheel of the other caster yieldingly into said plane.

13. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster Wheel movable into and out of said plane, an actuating lever associated with each supplementary caster, means interconnecting each lever with the adjacent supplementary caster wheel for moving it in one direction relatively to said plane, and means interconnecting the supplementary caster wheels operable when one is moved in said direction to move the other in the opposite direction relatively to said plane.

14. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, an actuating lever associated with each supplementary caster, means interconnecting each lever with the adjacent supplementary caster wheel for moving it in one direction relatively to said plane, means interconnecting the supplementary caster wheels operable when one is moved in said direction to move the other in the opposite direction relatively to said plane, and means for releasably locking each lever after its actuation to move said adjacent supplementary caster wheel.

15. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movable into and out of said plane, an actuating lever associated with each supplementary caster, means interconnecting each lever with the adjacent supplementary caster wheel for moving it in one direction relatively to said plane, means interconnecting the supplementary caster wheels operable when one is moved in said direction to move the other in the opposite direction relatively to said plane, and means for releasably locking each lever after its actuation to move said adjacent supplementary caster wheel, each of said last mentioned means comprising a latching lever adapted to engage in a notch in the adjacent actuating lever to thereby inhibit movement thereof in one direction.

16. In combination with a truck or the like including a plurality of swivel casters having caster wheels disposed in substantially the same horizontal plane, a supplementary caster adjacent each end of the truck comprising a caster wheel movably into and out of said plane, an actuating lever associated with each supplementary caster, means interconnecting each lever with the adjacent supplementary caster wheel for moving it in one direction relatively to said plane, means interconnecting the supplementary caster wheels operable when one is moved in said direction to yieldingly move the other in the opposite direction relatively to said plane, and means for releasably locking each lever after its actuation to move said adjacent supplementary caster Wheel.

IRVIN F. SCI-IRECK.

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