Excavating – Combined or convertible – With scraper
Reexamination Certificate
2000-03-07
2002-09-10
Will, Thomas B. (Department: 3671)
Excavating
Combined or convertible
With scraper
C172S275000, C414S686000
Reexamination Certificate
active
06446367
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a working vehicle having a front loader attached to the front of a tractor, and mainly to a working vehicle called a TLB (tractor-loader-backhoe) having a front loader attached to the front of a tractor, and a backhoe attached to the rear of the tractor.
2. Description of the Related Art
Conventionally, there is a working vehicle called a TLB which has a front loader attached to the front of a tractor, and a backhoe attached to the rear of the tractor.
In the TLB, the tractor includes a reinforcing frame extending longitudinally thereof. The front loader is attached to the front end of the reinforcing frame, and the backhoe to the rear end of the reinforcing frame.
The front loader includes side frames in post form attached to the reinforcing frame, braces for connecting the side frames to the tractor, booms attached to the side frames to be vertically pivotable by boom cylinders, and a bucket disposed at distal ends of the booms to be actuated by a bucket cylinder to perform scooping and dumping operations.
Regarding the TLB in operation, a load is applied to the side frames during an operation with the front loader. In addition, during an operation of the backhoe, the front loader is used as a stabilizer with the bucket of the front loader placed in contact with the ground. Thus, during an operation of the backhoe also, a load is applied to the side frames through the reinforcing frame.
The braces are provided to connect the side frame to the tractor, so that the load applied to the side frames is distributed to the braces. However, where the side frames are rigidly joined to the reinforcing frame, stress tends to concentrate on the joints therebetween, and it is difficult to distribute the load from the side frames to the braces. However, where the side frames are connected to the reinforcing frame in a fully free contact mode simply to receive the load, a drawback arises with respect to stability of the front loader.
In one construction to attach the side frames to the reinforcing frame, lower positions of the side frames are fitted, to be pivotable about a transverse axis, from above to loader mounts attached to the reinforcing frame, and upper positions of the side frames are pinned to the loader mounts. In this construction, the lower fitting positions of the side frames have considerable play, and an excessive load is transmitted from the side frames to the braces. This requires the braces to be reinforced. Particularly during an excavating operation with the backhoe attached to the tractor, with the bucket of the front loader placed on the ground to use the front loader as a stabilizer, the above construction has a drawback that the front loader cannot fully bear the load transmitted from the backhoe.
SUMMARY OF THE INVENTION
An object of this invention is to allow a load applied to the side frames to be distributed smoothly to the braces, to appropriately reduce the stress concentration on the portions of the side frame fixed to the reinforcing frame.
The above object is fulfilled, according to this invention, by a tractor comprising a tractor body, a reinforcing frame disposed around the tractor body and supported by the tractor body, a pair of right and left side frames for pivotably supporting a pair of right and left booms having a loader bucket attached to distal ends thereof, braces for connecting the side frames to the tractor body, and a connecting device for connecting the side frames to the reinforcing frame, the connecting device including at least two connected bosses attached to the side frames, at least two connecting bosses attached to the reinforcing frame, and pins inserted through bores of the connected bosses and bores of the connecting bosses.
With this construction, the side frames are not so fully rigidly joined to loader mounts of the reinforcing frame as by tightening bolts. Though very slight, movement is allowed so that a load applied to the side frames may be distributed (released) to the braces. As a result, without reinforcing the mounts that attach the side frames to the reinforcing frame, the front loader, and a backhoe attached as necessary, may perform operations with increased power.
Since the load applied to the side frames may be released appropriately to the braces, components of the reinforcing frame may have a small wall thickness to achieve reductions in weight and cost. The pin connection realizes a reduction in assembling steps, a simplified construction and low cost.
Further, in this invention, a rear mounting device is provided for attaching rear positions of the reinforcing frame to cylindrical portions of rear axle cases. The rear mounting device includes holders rotatable about an axis of the cylindrical portions, and mounting members for connecting the holders to the reinforcing frame, respectively. Preferably, the mounting members and the holders are bolted to together.
Such a mounting structure at the rear end of the reinforcing frame in combination with the mounting structure (pin connection) for attaching the side frames to the reinforcing frame effectively distributes the load acting on the reinforcing frame during a backhoe operation to the entire reinforcing frame and the entire front loader. Consequently, the reinforcing frame may be simplified and lightened.
Since the holders are mounted on the rear axle cases to be rotatable about the axis thereof, and bolted to the rear end of the reinforcing frame, the reinforcing frame is attached with errors in mounting dimension due to a welding distortion or the like of the reinforcing frame absorbed by play in rotation of the holders and in bolt receiving bores, and without producing a stress of assembly.
Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings.
REFERENCES:
patent: 4498839 (1985-02-01), Williams et al.
patent: 4565989 (1986-01-01), Lotter et al.
patent: 4755101 (1988-07-01), Hamada et al.
patent: 4802814 (1989-02-01), Kourogi et al.
patent: 5000269 (1991-03-01), Aoki et al.
patent: 5536134 (1996-07-01), Hirooka
patent: 5927665 (1999-07-01), Grabnic
patent: 6056502 (2000-05-01), Takemura et al.
patent: 2256213 (1992-02-01), None
Aoki Tsuyoshi
Kawamura Shoichiro
Muramoto Naoya
Takemura Toshihiko
Kubota Corporation
Petravick Meredith C.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
Will Thomas B.
LandOfFree
Tractor-loader-backhoe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tractor-loader-backhoe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tractor-loader-backhoe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2880437