US2500293A - Vibratory dump truck - Google Patents

Description

March 14, 1950 ,pp. O'CONNOR 2,500,293

VIBRATORY DUMP TRUCK Filed June 9, 1944 l' llll /lllllllfl" Fig " II IIIIIIIIIII 3nventor F Jain C 05 a E E a flomeg:

Patented Mar. 14, 1950 VIBRATORY DUMP TRUCK John C. O'Connor, Dayton, Ohio, assignor to The OConnor Patent Company, Ann Arbor, Mich., a corporation of Michigan Application June 9, 1944, Serial No. 539,588

12 Claims.

1 This invention relates to vibratory apparatus and in particular to vibratory apparatus attached to or forming part of a truck to facilitate the load:-

ing and unloading of freight.

Many trucks are built with self-contained means for discharging the load. The usual method is to employ a hydraulic cylinder or mechanical means to'elevate the front end of the bed or box of the truck thus causing the material to slide to the rear and to be discharged therefrom. Another example of a self-unloading truck is one which is equipped with a concrete mixer. Such a truck is loaded with the ingredients at the builders sup-" ply yard, mixes the ingredients during the transit to the customers premises and discharges the mixed concrete by opening the mixer and continuing its operation.

The principal object of this invention is to pro-v vide a self-dumping truck in which the unloading is accomplished by. vibrating the material containing portion of the truck.

Another object of the invention is to provide means for uniformly distributing a load of material over an area.

Another object is to provide a self-dumping truck which is also capable of mixing the ingre- Figure V is a. fragmentary side elevation of a vibratory material mixing and conveying truck in which the vibratory forcejsapplied tothe frame of the truck.

Figure VI is a side elevation of a tractor and wagon in which the wagon is provided with vibratory unloading means driven from-the tractor.

These specific examples are, intended merely to illustrate the invention and not to impose limitations on the scope of the invention.

As mentioned in the objects, the present invention lies in utilizing vibration for the unloading of material from a truck. The vibraticnmay also be used, under certain conditions, to move material from the rear end of the truck bed to the forward end thus minimizing the labor or" loading.

Various methods may be used to generate the vibrations and transmit the vibratory force to the bed of the truck. In a copending application Serial Number 427,039, now Patent No. 2,353,492, granted July 11, 1944, a method of generating vibration in one portion of a structure without dients of a load prior'to the discharge of the load.

A further object is to provide a self-unloading truck which is capable of unloading loose, packaged or crated material and which unloads the material without tipping the bed of thetruck.

A still further object is to provide a self-unloading truck in which the unloading is performed by Figure I is' a simple schematic diag'ram of a structure in which a material contacting member may be vigorously vibrated without materially vibratingthe remainder of the structure or transmittihg vibrational energy to the foundation.

Figure II shows a portable structure similar that of Figure-I. j q g Figure III shows a self-unloading truck in which the unloading is accomplished by vibration applied'to the frame of the'truck.

Figure IV is 'a' fragmentary side elevation of selfeu'filoading truck similarto'that which is shown-"in Figure III but'equippedwith an'adjustableendgate. I

materially vibrating other portions is described. Theinvention herein'comprises the use of that method for producing the required vibration.

The simplest exciting mechanism, from the standpoint of performance and easeof'maintenance, is a rotating shaft carrying eccentric Weights. Such a shaft may be journaled in the frame of the truck. When the shaft is 'journaled in the frame of the truck the vibrational force is transmitted through the frame and the resilient member supporting the bed to the bed of the truck in the manner described in the mentioned copending application. According to that invention the vibratory system comprising the resilient members and the bed of the truck is designed to have'a resonant frequency in the range of the speed of the rotating shaft. When the speed of the shaft substantially equals the natural frequency of the vibratory system the vibratory. system acts as a tuned undamped vibration -ab- I sorber' and by its own vibration absorbs i-and counteracts the vibratory force applied to the frame of the truck by the rotating eccentric weights.

truck is closed and the'material is allowed to accumulate and circulate at that end.

Figure Ischematically illustrates a structure in.

which-vibratory. force applied to one member causesvibration of another member without vibrating the first member. The structure com- In this use 3, prises a material contacting member ID supported by springs II and I2 from a frame or base member l3 which in turn is resiliently mounted from a foundation II by springs IE and I6. A shaft journaled in the frame |3 carries an eccentric weight I8. Such a system is capable of several modes of vibration. The first mode of interest is a vibration in which the members Ill and I3 vibrate vertically on the springs l5 and Hi. This type of vibration may be excited by rotating the shaft H at an appropriate speed. At another and higher speed, another mode of vibration in'which the members Ill and I3 move in opposite directions may be produced. At an intermediate speed the member may be caused to vibrate on the springs H and I2 in such phase and amplitude that the resulting forces applied to the frame l3 cancel the centrifugal force of the rotating unbalanced weight l8 leaving the frame |3 substantially quiescent. This last mode is very efficient because practically no energy is transmitted through the springs l5 and It to the foundation from the quiescent base or frame l3. Such a structure may be made portable, as is schematicall illustrated in Figure II, by substituting resiliently tired wheels for the springs l5 and IS. The resulting structure comprises a material contacting or containing member l3, which may be a mold box, a short vibratory conveyer, or similar object to be vibrated, mounted on springs 20 and 2| from a frame 22. The frame 22 is carried on resiliently tired wheels 23 and 24. The frame 22 also journals a shaft 25 bearing an eccentric weight 23. The centrifugal forces produced by the rotation of the shaft 25 and eccentric weight 26 are transmitted through the frame 22 to the springs" and 2| and through them to the material contacting member l9. If the speed of rotation of the shaft 25 corresponds to the natural frequency of the material contacting member I! on the springs 20 and 2| a resonant vibration is set up in the member IS without producing an appreciable vibration of the frame 22. This structure thus has the advantages of being capable of producing a vigorous efllcient vibration and of being easily transported from one location to another.

As the material contacting member may be a conveyer and as the whole structure is portable, such a structure could be used to transport material from one location to another by loading the conveyer and then by the vibratory action of the conveyer automatically discharge the material from the conveyer at the destination. A structure used in this manner might be called a self-unloading or self-dumping truck. Figures 111 and IV show trucks so equipped. In each of these structures a truck 21 having a frame 28 carried on resilient wheels 2! and 30 (not shown in Fi ure IV) supports a bed or material containing box 3|. Springs 32 allowing unidirectional motion of the box 3| with respect to the frame 28 are interposed between the frame 28 and the box 3|. The springs 32 are in the form of cantilevers extending upwardly and forwardly from the frame 23 to the box 3|. These springs are stressed in bending so the resulting vibration is along a path inclined toward the rear in such a direction that material contained in the box 3| will be conveyed toward the rear of the truck. The springs 32 are a preferred form of resilient means for mounting the box 3|, but any other form of spring which would allow motion of the box 3| in a generally straight path inclined in the direction toward which the material is to move would be operatire.

The vibration is produced by the centrifugal force of a rotating eccentric weight 33 carried on a shaft 34 transversely journaled in the frame 28. The shaft 34 is driven by a V-belt 35 from a pulley 36 extending from an auxiliary transmission indicated generally as 31. The auxiliary transmission 37 is controlled by a lever 38 and provides means for connecting the pulley 33 to the engine of the truck. In this structure vibration of the box 3| is produced by the centrifugal forces of the weight 33 which are transmitted through the frame 28 and the springs 32. This type of truck is unloaded either while it is in motion or while it is standing still by engaging the auxiliary transmission 31 and driving the unbalanced weight 33 at a speed substantially equal to the resonant frequency of the box 3| on the springs 32.

In the dump trucks of Figures III, IV, V and VI, the vibration is shown as being produced by rotation of an eccentrically weighted shaft but, of course, the particular mechanism employed to apply cyclical force to the truck body is immaterial. Any means such as s, pneumatically reciprocated weight acting on a line at least approximately parallel to the direction of movement of the box 3| or other mechanisms, will function equally effectively.

In these structures, the resilient tires 29 serve as the base or isolating springs comparable to the springs l5 and |6 of Figure I. However, since the only function of the springs l5 and I6 is to vibrationally isolate the base I3 from the earth, the truck body 23 can be isolated either by the tires, as shown, or by ordinary vehicle springs (not shown).

This structure (as shown in either Figure III or IV) is capable of unloading any type of load except perhaps a wet mud. Suppose for example a crate of machinery is on the bed 3| and the weight 34 is rotated clockwise. The centrifugal force of the weight will tend to slide the bed 3| horizontally under the crate of machinery while the vertical centrifugal force will alternately increase and decrease the pressure between the crate and the bed. With clockwise rotation the bed tends to move forward when the pressure is least and to move rearward when the pressure is greatest. The resulting net force moves the load toward the rear. If the direction of rotation is reversed the direction of travel of the load is reversed and a crate placed at the rear of the truck bed will travel toward the front of the truck. It is desirable that the acceleration of the bed of the truck produced by the centrifugal force exceed the gravitational constant "9" in order that the force between the load and the bed of the truck shall become zero or nearly so during the forward motion of the bed.

The material containers of the trucks 21 may be equipped with an adjustable end gate so that the truck so equipped may be used for spreading material over an area. Figure IV shows the truck 21 so equipped. The box orbed3| isequipped with an adjustable end gate 39. The end gate 33 is provided with horizontally projecting ears 40 through which is threaded a vertical screw ll journaled in a bracket 42 secured to the side of the box 3|. The lower end of the screw 4| is provided with a hand wheel 43. When the truck is so equipped and the vibrator is operated the ma-:

terial is conveyed to the rear of the truck where it Jams against the and gate. The material at the bottom slides through under the end gate and is discharged. The rate of discharge is conproduced by the centrifugal forces of the rotat- I ing weight.

If the material is not allowed to escape the vibration of the bed merely piles it up against the end gate and the top layers or strata slide forward while the bottom strata are fed'toward the gate. The material thus circulates and in the process of circulation becomes thoroughly mixed. Because while being mixed, the material tends to accumulate at the rear end of the material container it is desirable to supply a hood or other cover to prevent its escape over the sides of the box. Figure V is a fragmentary view of the truck 21 showing a hood 44 added to the box or container 3|. The hood 44 is attached to the top of the material container 3| and cooperates with the sides and the end gate 39 to prevent the escape of the material as it circulates. After the material has been mixed by the circulation it is discharged by opening the end gates.

It is not necessary that motive power for driving the vibrator or rotating shaft be self-contained within the vehicle. The vibrating structure may be built into a wagon and the wagon drawn by a tractor equipped with a power takeoff. The structure shown in Figure VI includes a wagon 45 adapted to be drawn by a tractor 46. The wagon 45 comprises a frame 41 supported on resilient wheels 48 and 49 and a wagon box or bed 50 supported from the frame 41 by a series of springs A shaft 52 is journaled transversely in the frame 41 and carries an eccentric weight 53. The shaft 52 isadapted to be driven through a shaft 54 connected to the power take-off of the tractor 46. Universal joints 55 at each end of the shaft 54 permit operation of the vibrator without requiring alignment ofthe wagon and tractor. Atongue 56 acts both as draw bar for the wagon and to steer the wagon. Because the tractor is conventional it will not be described further except to say that the power take-off is of a type which may be controlled independently of the power transmission to the driving wheels. In this arrangement, as in the others, the box 50 and the spring 5| comprise a vibratory structure having a resonant frequency within the speed range of the shaft 52 hearing the unbalanced weight 53. Therefore, as in the other structure, a vibration of the box may be excited by rotation of the shaft 52 without materially vibrating the frame 49. This structure is admirably suited to the spreading of materials such as gravel on roads and lime or fertilizer on cultivated land.

The specific structures described illustrate the essential elements needed to produce a vibratory dump truck. A vibratory dump truck possesses several distinctive advantages over conventional dump trucks. One advantage is the fact that it may be built with a much lower center of gravity and is, therefore, much less likely to upset when maneuvering in construction areas. Another advantage is that it is capable of discharging the load without lowering the rear end of the bed.

material up to get rollers under it or employing a used as a low center of gravity concrete mixer and in that use is much more maneuverable than conventional transit mixers.

Having described my invention, I claim:

1. In a device of the class described, in combination, a-vehicle, a commodity container, re-

block and tackle to slide it along the bed. When I Y silient means supporting said container from said vehicle and forming therewith a vibratory system having a resonant frequency, a shaft bearing eccentric weights journaled transversely in said vehicle, and means for rotating said shaft at substantially the resonant frequency of the vibratory system comprising said container and said resilient means.

2. In a device of the class described, in combination, a vehicle, means for moving said vehicle, a material container, resilient means supporting said container on said vehicle and forming therewith a vibratory system, a shaft extending transversely of said vehicle and journaled therein, eccentric weights carried on said shaft, means for rotating said shaft at substantially the natural frequency of said system thereby exciting vibration of said container tending to move a material in said container toward an end thereof, and an adjustable gate closing that end of 'said container adapted to control the discharge energy supplied to the frame.

4. In a device of the class described,in combi nation, a vehicle chassis the frame of which is resiliently supported, a material container, resilient means for supporting the container from the vehicle frame and for forming with the container a vibratory system having a resonant frequency, and an unbalanced rotating weight that is journaled in the vehicle frame and that is rotated at the resonant frequency of the vibratory system.

5. In a device of the class described, in combination, a vehicle chassis the frame of which is resiliently supported, a material container, resilient means for supporting the container from the vehicle frame and for forming with the container a vibratory system having a resonant frequeney, and an unbalanced weight that is mounted on a shaft journaled in and extending transversely of the frame and that is rotated at a speed substantially equal to the resonant frequency of the vibratory system.

. 6. In a device of the class described, in combination, a vehicle chassis the frame of which is resiliently supported, a commodity container, resilient means for supporting the container from the vehicle frame andfor forming with the container a vibratory system havinga resonant frequency, a masssupported from and movable with respect to the frame, and means for cyclically moving the mass with the reaction force from the means applying vibratory force to the frame, said means operating at a frequency substantially equal to the resonant frequency of the vibratory system whereby the vibratory system by its own vibration absorbs substantially all the 7- vibrational energy imparted to the frame by the means for moving the mass.

'7. In a device of the class described, in combination, a Vehicle, means for moving said vehicle, amaterial container having a-longitudi- I nally extending approximately planar bed, a plurality of forwardly and upwardly extending leaf springs for supporting said container on said vehicle and forming with said container a vibratory system having a natural frequency of vibration, a shaft extending transversely of said vehicle and journaled therein, eccentric weights carried on said shaft, means for rotating said shaft at substantially the natural frequency of said system thereby exciting vibration of said container tending to movea material in said container toward an end thereof, and an adjustable gate closing that end of said container adapted to control the discharge of material from said container.

8. A portable vibratory conveyor comprising, in combination, a wheeled vehicle having a frame resiliently isolated from the ground, a conveyor body having a longitudinally extending substantially planar bed, a plurality of upwardly inclined, substantially parallel leaf springs for supporting said body on said frame and forming with said conveyor body a vibratory system having a natural frequency of vibration, and means for applying cyclical force to said frame at substantially the natural frequency of said system, thereby exciting vibration of said container tending to move material therein toward one end thereof.

9. A vibratory dump truck comprising, in combination, a truck frame, resilient means including wheels for supporting said truck frame, a material containing body having a longitudinally extending, substantially planar bed and an open rear end, an adjustable rear end gate, springs for supporting said body on said frame and forming with said body a vibratory system having a natural frequency of vibration, said springs being adapted to restrain movement of said body except along a path extending generally upwardly and rearwardl relative to said truck frame, and means for applying a cyclical force to said frame at substantially the natural frequency of said vibratory system thereby exciting vibration in said body for moving the material contained therein toward the rear end thereof.

10. A vibratory dump truck comprising, in combination, a truck frame, resilient means including wheels for supporting said truck frame, a material containing body having a longitudinally extend'ng, substantially planar bed and an open rear end, an adjustable rear end gate, a plurality of generally parallel, forwardly and upwardly extending leaf springs for supporting said body on said frame and forming with said body 9, vibratory system having a natural frequency of vibration, the ends of each of said springs being fixedly connected to said truck frame and to said for moving the material contained therein toward the rear end thereof.

11. A vibratory dump truck comprising, in combination, a truck frame, resilient tired wheels for supporting said truck frame on the ground, motive power means for said truck frame, a material containing body having a longitudinally extending, substantially planar bed and an open rear end, an adjustable rear end gate, a plurality of generally parallel, forwardly and upwardly extendingv leaf springs for supporting said body on said frame and forming with said body a vibratory system having a natural frequency of vibration, the ends of each of said springs being fixedly connected to said truck frame and to said body respectively and an eccentrically weighted, transversely extending, shaft journalled in said truck frame and rotatable in its journals for applying cyclical force to said frame at substantially the natural frequency of the vibratory system formed by said body and said springs and thereby inducing vibration in said body along a generally upwardly and rearwardly directed path for moving the material contained therein toward the rear end thereof.

12, A portable vibratory conveyor comprising, in combination, a frame having resilient tired wheels, a conveyor body having a longitudinally extending substantially planar bed, a plurality of upwardly and forwardly inclined, substantially parallel leaf springs for supporting said body on said frame and forming with said body a vibratory system having a natural frequency of vibration, means for fixedly mounting the ends of said springs on said frame and said body respectively and an eccentrically weighted transversely extending shaft journalled in said frame and rotatable for applying cyclical force to said frame at substantially the natural frequency of the system formed by saidibody and said springs, and thereby exciting vibration in said bod tending to move material contained therein toward one end thereof.

JOHN C. O'CONNOR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 749,695 Litchfield Jan. 12, 1904 833,761 Stevens Oct. 23, 1906 1,820,239 Merz Aug. 25, 1931 1,858,328 Heymann et a! May 17, 193 1,922,447 Miller et al 'Aug. 15, 1933 1,990,765 Wettlaufer Feb. 12, 1935 2,060,130 Scott Nov. 10, 1936 2,108,416 Smith et al Feb. 15, 1938 2,139,162 Jenkins Dec. 6, 1938 2,243,936 Wurzbach et al. June 3, 1941 2,353,492 O'Connor July 11, 1944 2,358,876 Overstrom Sept. 26, 1944 ,374,663 Garrier May 1, 1945 FOREIGN PATENTS Number Country Date 216,256 Great Britain May 29, 1924 648,127 Germany July 22, 1937

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