Tractor-scraper With Moveable Floor

Abstract

A tractor-scraper combination includes a scraper having a bowl supported by a rear axle, and a floor slidable on the bowl and attached to and supported by hitch means on the tractor. Power means is provided for sliding the floor and tractor forwardly with respect to the scraper bowl and axle, providing an opening in the bottom of the bowl through which material is expelled.

Description

BACKGROUND OF THE INVENTION

This invention relates to tractor-drawn earthmoving scrapers and more particularly to means for unloading scrapers. The usual means of unloading such scrapers is to provide for sliding of a front portion of the scraper floor back under a rear portion of the floor. Material is then expelled through the front floor opening by extension of a rear wall ejector plate, or by lowering an elevator into the bowl and running it in reverse.

Other means provided for unloading scrapers comprise a floor that can be rotated upwardly and rearwardly.

Many of these constructions do not provide for complete opening of the bottom of the bowl which results in slower unloading times. Also, in scrapers where only a portion of the floor opens, an ejector mechanism, such as a push-type end wall, must be provided which increases the length and complexity of the machine. Also, when only a portion of the floor opens, the material can sometimes bridge the opening.

If the scraper floor is arranged to pivot upwardly and rearwardly, the center of gravity of the scraper is raised to adversely affect the stability of the machine.

SUMMARY OF THE INVENTION

The present invention provides a tractor-scraper combination in which substantially the entire floor of the scraper bowl is opened for unloading. The wheel base of the tractor-scraper combination is variable so that it is normally quite short but may be extended for unloading. No portion of the scraper need be raised to facilitate unloading. Accordingly, the tractor-scraper combination has a low center of gravity and a normally short wheel base, providing improved stability and maneuverability.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects of this invention will be apparent from the following description and accompanying drawings wherein:

FIG. 1 is a side elevational view of a preferred embodiment of the tractor-scraper combination of the present invention.

FIG. 2 is a cross-sectional view of the scraper taken in the direction of arrows II--II IN FIG. 1.

FIG. 3 is a partial, side elevational view similar to FIG. 1 illustrating another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a preferred embodiment of the present invention is shown as including a tractor 10 connected by hitch means 11 to a scraper 12. The tractor comprises a frame 13, an engine 14, an operator's station 15, and wheels 16. The tractor is connected to the scraper by hitch means comprising a swivel 17, a gooseneck 18, a transverse spreader 19 and a pair of spaced draft arms 20 (one shown).

The scraper comprises a bowl 22, including spaced side walls 23, supported on a pair of wheels 24 by a frame 25. A U-shaped floor 26 encompasses the lower portion of the side walls 23 and is supported on each wall by two pairs of rollers 27 and 28 engaging guide rails 29 attached to the side wall (FIG. 2). A cutting edge 31 is attached to the forward edge of the floor and projects forwardly and downwardly therefrom. A triangular bar 32 extends between the lower forward portions of the side walls for support thereof.

An elevator mechanism 33 may be disposed at the forward end of the bowl and above the cutting edge to assist in loading material engaged by the cutting edge. Such mechanisms are well-known and will not be further described. The present invention may also be embodied in other scrapers such as those in which the front of the bowl is closed by an apron.

The rear of the bowl is closed by an end wall 34 pivotally mounted on the side walls by a torsion bar 34a extending therethrough, to allow the lower end thereof to swing between the floor 26 and stops 35 fixed to the side walls. A link 36 is attached at one end to each end of torsion bar 34a disposed outwardly of the side wall and has the rod end of a hydraulic unloading actuator comprising a double-acting cylinder 37 pivotally connected to its other end at 38. The cylinder end of the unloading jack is pivotally connected to the scraper floor at 39. Draft arms 20 are pivotally connected to the floor at 41. The front of the bowl is adjustably supported for vertical movement by a pair of hydraulic jacks 42 (one shown) pivotally connected to the floor at 43 and to the transverse spreader by means of brackets 44.

In operation, the FIG. 1 scraper is loaded in the conventional manner by lowering the front of the bowl by jacks 42 until cutting edge 31 engages and directs the scraped material into the closed bowl upon forward movement of the tractor-scraper. Such loading may be assisted by elevator 33 in a conventional manner. When loading is completed, the front of the bowl is lifted by jacks 42 until the cutting edge clears the ground. The load may then be transported to the dumping site.

To unload the scraper, hydraulic cylinders 37 are extended by suitable control means (not shown) to rotate end wall 34 rearwardly to its phantom line position until it engages stops 35. Such positioning of the end wall forms an opening A in the bottom of the bowl. Further extension of the cylinders will produce relative motion as between the attached scraper floor and tractor and the scraper bowl to thus form a larger opening B. Accordingly, the wheel base of the tractor-scraper combination will be extended a distance of B minus A during the unloading phase of scraper operation. When the scraper has been unloaded, cylinders 37 are retracted until the floor again closes the bottom of the bowl in cooperation with the end wall, whereupon the tractor-scraper combination will again assume its normal wheel base configuration.

Another embodiment of the present invention is shown in FIG. 3. This embodiment is similar to the FIG. 1 embodiment except that only a front section 52 of a scraper floor 51 is slidable, while a rear section 53 is fixed to the side walls 22 of the bowl. A rear end wall 55 of the bowl comprises a conventional ejector plate which can be moved forwardly by a hydraulic actuator 56.

A pair of unloading cylinders 57 (one shown) are connected between the slidable front portion 52 of the floor and the side walls. Extension of the unloading cylinders will open the floor a distance C whereupon material may be pushed out the opening by end wall 55 upon extension of actuator 56. Such a construction will results in a wheel base extension only about one-half of that produced by the embodiment shown in FIG. 1, with a result that the unloading cylinders need be able to extend only about half as far, and the wheel base of the tractor-scraper combination will extend only half as far.

Claims

I claim:

1. In a tractor-scraper combination including hitch means attaching a wheel-mounted scraper bowl, having laterally spaced sidewalls, to a wheel-mounted tractor, the invention comprising floor means movably mounted in said scraper bowl to normally close a bottom opening thereof and wherein said floor means is operatively connected to said hitch means for movement therewith relative to said sidewalls, and further comprising means connected to said floor means for so moving said floor means relative to said sidewalls.

2. The invention of claim 1 wherein said floor means is slidably mounted on and disposed between said side walls.

3. The invention of claim 1 wherein the forward end of the floor means is attached to and vertically supported by extensible and retractable cylinder means attached to said hitch means.

4. The invention of claim 1 wherein said bowl further comprises an end wall pivotally mounted on the bowl to close the rear thereof and link means pivotally connected to the end wall for movement therewith and to said actuating means.

5. The invention of claim 4 further comprising stop means on the side walls for limiting rearward pivotal movement of the end wall.

6. The invention of claim 1 wherein the front of the bowl is normally closed by an elevator mechanism.

7. The invention of claim 1 further comprising an ejector-type end wall closing the rear of the bowl and slidable therein and actuating means connected to the said end wall and to said bowl for moving said end wall therein.

8. The invention of claim 7 wherein a front portion of the floor means is slidably mounted on the side walls and a substantial rear portion of the floor means is fixed thereto.