The present invention relates to an excavator assembly having a rearwardly extending excavator arm and a rotatable post mounted on a tractor, wherein the excavator assembly is fastened to the tractor's three-point suspension, i.e., two lower draw bars and a top stay, wherein the excavator assembly is disposed between the draw bars and mounted by means of a vertical frame which is secured to the excavator post, and wherein the frame is adapted to form an attachment for a rearwardly facing, tippable tractor shovel.
From DE-A-2 757 921 there is previously known a silage milling device, comprising an individually detachable excavator in the form of a rigid arm which is pivotally and swingably connected to a tractor-mounted shovel assembly and carries a milling drum at its outer end.
The object of the present invention is to provide an improved excavator assembly which is more versatile than prior art excavator assemblies of the above defined type.
To this end it is proposed in accordance with the invention that in an assembly of the kind described the excavator comprises an articulated two-part excavator arm having means at the outer free end of the outer arm memberfor pivotally mounting an excavator bucket and an hydraulic cylinder for pivoting said bucket, and in that the lower part of the frame has a downwardly open recess permitting a drag to be connected to the tractor's normal hitch. The arrangement according to the invention allows the excavator bucket and the tractor shovel to be individually attached and detached from the tractor, thus allowing the tractor to be used as needed with any one of or both the excavator bucket and the tractor shovel, or with another tool. When the tractor shovel is detached, a conventional trailer can be attached to the tractor and can be loaded by the excavator bucket or other tool, such as a timber loading hook or grab.
A practical embodiment of the invention is characterized by the provision of two sets of fastener holes in the frame for both the top stay and the two draw bars, the sets of holes being disposed in different vertical planes.
A further feature of the invention is that the excavator post is situated to one side of the tractor's centerline. The purpose of this is to permit the top stay to be utilized for fastening the tractor shovel, and to make room for release of the latching hook, so that the tractor shovel can be emptied. This arrangement also provides sufficient space for a simple and robust shovel pivoting means between the draw bars. The driver also has a better view of the area being excavated, and when a trailer also is attached to the tractor, he can complete the entire excavation job in essentially one work operation. This arrangement also permits the excavator arm to reach farther out to the side making it easier to excavate alongside a wall or fence.
The invention will be explained in greater detail in the following with reference to the accompanying drawings, which show a preferred embodiment of the invention.
The drawings show the rear part 1 of a tractor with a rear wheel 2. Mounted in the conventional manner on the tractor are two draw bars 3 and 4 and a top stay, indicated by a centerline 5. The draw bars are tiltable by means of hydraulic arms in a vertical plane, while the top stay is normally a conventional tie rod which can be arranged to be easily adjustable.
The excavator assembly consists of a vertical frame 6 which is rigidly fastened to the excavator post 7. The frame 6 is substantially T-shaped with an upright member 8 and two lower, projecting legs 9 and 10. Two sets of holes 11 and 12 for the top stay 5 are arranged at the upper part of the vertical member 8. The two rows of holes also permit the excavator post to be positioned diagonally. Lugs 13 with two sets of holes 14 and 15 for fastening the draw bars 3, 4 are secured to the outer ends of the legs 9 and 10. If the fastener holes 11 and 15 are used, the excavator bucket will be located farther away from the tractor, and if the holes 12 and 14 are used, the excavator bucket will be mounted closer to the tractor. This position is precisely the position which the tractor shovel will have when it is being utilized without the excavator bucket. In this case the tractor shovel is fastened to the same three bolts as those to which the excavator is fastened. Attached to the upper end of the rotatable post 7 is a bracket 16 with an inner arm 17 hinged to the outer end thereof, and an outer arm 18 is hinged to the outer end of the inner arm 17. The two arm members are moved by means of hydraulic cylinders 19 and 20. An excavator bucket 21 is pivotally fastened to the outer end of the arm 18, and it can be pivoted by means of a hydraulic cylinder 22. An additional frame 23 is secured to the vertical frame 6, which can be a standard frame, and a tractor shovel 24 is secured to the frame 23.
The tractor shovel is hinged to the frame at 25 and secured at the upper edge thereof by means of a latching hook 26.
The post 7 of the excavator assembly is pivotable by means of a special assembly which requires little space, and this assembly consists of a hydraulic cylinder 27 which is secured to the frame 6 by means of lugs 28 and which turns a rotatable shaft 29 fastened to the frame via lugs 30. A sprocket wheel 31 is secured to the shaft and via a chain 32 it drives a sprocket wheel 33 on the rotatable post 7. With a gear ratio of 2:1 between the wheels, the excavator arm can be pivoted 180° with a relatively short cylinder 27.
By means of the embodiment illustrated in the drawings, the excavator bucket and tractor shovel can both be mounted on the tractor at the same time. The tractor shovel can retain its normal position and perform its normal functions, i.e., be raised, lowered and tipped.
The excavator bucket can excavate mass, for example, frozen earth, frozen fertilizer and the like, and empty it into or push it onto the tractor shovel. The tractor shovel can then be elevated by means of the three-point suspension, transported in the normal way and emptied by releasing the latching hook 26.
The tractor shovel can also be used as a support foot for the excavator. It could also in that case be filled with mass, to make it even sturdier. Optionally, additional support feet can also be arranged at the rear corners of the shovel, for use in especially difficult terrain. These must in that case be disposed so as not to hinder normal use of the shovel.
When mass is being dug into with the tractor shovel, the shovel will force its way into the mass owing to the work done by the excavator, so that the tractor will stand firm even if the ground is very slippery.
The excavator can also operate as a normal excavator, digging both rearwardly and to both sides of the tractor shovel. It can also dig a ditch even if the tractor shovel is mounted. The excavator can of course also be used as a normal digger. The shovel is then removed, which permits greater excavation depths and excavation closer to the tractor.
When excavating without the tractor shovel, the projecting legs 9 and 10 can be extended and provided with mechanical or hydraulic support feet.
The excavator is so small that the tractor's own hydraulic pump will have sufficient oil capacity for the excavator's hydraulic cylinders. An automatically closing hydraulic oil outlet is found at the rear of the tractor. Oil can be led from the outlet to the various hydraulic cylinders via an extra valve block, etc. This permits one to avoid the conventional method requiring the use of an extra pump driven from the tractor's power outlet. This also saves space, so that there will be room for the excavator's frame, post and rotating means between the tractor and the shovel.
By means of the frame configuration described above, a tractor trailer could for example be connected to the tractor hitch. The excavator frame can optionally be elevated into a somewhat higher position. One could then excavate on both sides of the trailer and optionally empty the excavated mass directly into the trailer. The trailer can be driven away and emptied even with the excavator bucket mounted.
The invention is not restricted to the exemplary embodiment described hereinabove and illustrated in the drawings. For example, instead of the bucket on the end of the excavator arm, a grab could be provided for loading timber and the like.
As mentioned previously, the lower part of the frame has a downwardly-open recess. This is necessary to provide space for connecting/dis- connecting a trailer, and also to provide the necessary clearance between the frame and the trailer hitch when the machine is in the normal excavating position.
The extension bracket 16 is provided so that the arm, when being pivoted, will clear the upper shovel bracket. The extension bracket is also important because the arm will then more easily clear the shovel, allowing one to excavate to a greater depth at the sides of and in back of the shovel.
The excavator assembly of the invention, when utilized strictly as an excavator, can perform the same work as other types of small three-point- mounted excavator assemblies. In addition, the excavator assembly of the invention can perform the following tasks
By means of the excavator assembly of the invention, therefore, it is possible using a conventional tractor or the like to perform entirely new combinations of tasks. This will be of particular importance in steep terrain. The fact that the excavator can remain attached to the tractor even when one needs to attach another implement to the rear of the tractor or to replace one rear-mounted implement with another is very important. On many farms, the farmer will be able to get by with one tractor less than he would need if he were using a conventional tractor-excavator.
The excavator post does not necessarily have to be placed to one side of the tractor's centerline. By using a special shovel, the excavator post could be placed on the tractor centerline.
The tractor's own hydraulic pump would not necessarily have to be used; a separate pump operated from the tractor's power outlet could also be utilized.