Patent Application
20060283056
1. Field of the Invention
This invention resides in the field of materials handling equipment that is used in the construction industry or other industries where earth moving is involved or the loading of materials is needed. In particular, this invention addresses components or attachments for use on backhoes or excavators that render the equipment usable for lifting heavy objects.
2. Description of the Prior Art
Various types of equipment are designed for scooping, lifting, moving, and depositing material such as sand, soil, gravel, and mud. Of these, the term “backhoe” generally refers to a power-operated boom with a normally vertical arm that is pivotally mounted to the boom and a rectangular bucket that is pivotally mounted to the arm. The boom, arm and bucket are able to pivot in combination within a single plane, forward or back, and in many cases the bucket can be pivoted laterally as well. The term “loader,” or particularly “front loader,” generally refers to a tractor that has a wide rectangular bucket mounted to its front end. The term “loader backhoe” generally refers to a tractor that has a loader with a wide rectangular bucket on the front and a backhoe on the rear, the backhoe being able to swing right or left over a range of about 200 degrees. The term “excavator” generally refers to a backhoe whose entire upper structure can rotate right or left over a range of 360 degrees. The term “backhoe or excavator” is used collectively herein to refer to any of these types of equipment.
In some cases, a backhoe or excavator is used for transporting heavy objects to or from a worksite. Objects that are often transported in this manner include structural components, logs, boulders, blocks and the like, often with decorative surfaces or features. A gripping claw or thumb is positioned on the equipment at a location close to the bucket such that the claw or thumb and the bucket together can grasp the object from both sides. Descriptions of claws or thumbs or other structures that allow a backhoe or excavator to grasp an object in this manner are found in the following United States patents:
The contents of these patents are incorporated herein by reference.
When a backhoe or excavator is used in this manner, it is important that a solid grip on any object be maintained. For many objects, however, it is also important to avoid damage to the object or to its surface. When logs are transported by these devices, for example, it is important not to pierce the log surface in such a manner that the log adheres to the gripping members but rather to allow the log to be released by simply separating the members. When decorative boulders and polished building materials are transported, it is important to avoid scratching or otherwise defacing the surface.
The present invention resides in an attachment to the boom of a backhoe or excavator that operates in conjunction with the bucket to grip large or heavy objects but has a distinct profile that offers a number of advantages over the thumbs and claws of the prior art. The attachment includes one or more plates having an exposed edge oriented to face the bucket opening when the bucket is pivoted back toward the boom. (In the claims hereto, the word “a” denotes “one or more.”) The edge has a scalloped shape formed by a series of convex (i.e., outwardly curved) protrusions arranged along the edge, each protrusion forming a smooth curve with no sharp points exposed, thereby allowing only the curved edges contact the object. In addition, the edge itself forms a generally concave curve, i.e., the extremities of the protrusions, which are the outermost sites along each individual protrusion that are closest to, and capable of contacting, the object, follow a line that describes a concave curve. In this way, at least two of the protrusions contact the object, and for curved objects such as logs or cylindrical or spherical objects in general, the series of protrusions generally follow the curvature of the object to reduce the chances of slippage.
In preferred embodiments of the invention, the attachment consists of two or more plates arranged in parallel orientation, preferably with scalloped edges curved and oriented in the same manner so that both plates operate in conjunction for further prevention of slippage. The plates can be joined by a connecting or base plate, optionally with additional transverse plates for dimensional stability, to form a unitary structure. The plate (or plates) is designed for secure attachment to the boom with no moving parts such as pivot pins, positioning pins, struts or arms. There is therefore no need for maintenance and no deterioration of the parts due to wear. The attachment allows the boom and bucket to grasp the object and to lift it, maneuver it, and place it securely without damage to the surface of the object or to the object itself.
Still further embodiments, features, and advantages of the invention will be apparent from the description that follows.
FIG.3 is a perspective view of the gripping attachment of the embodiment shown in
While the concepts and features that define the present invention can be implemented in a variety of configurations and constructions, a general understanding of these concepts and features can be gained by a detailed study of one particular embodiment. The attached drawings and the following description focus on one such embodiment.
The various plates of the gripping attachment can be joined by conventional means, such as bolting, welding, machining, or the like, and entire attachment can likewise be secured to the boom 12 through the base plate 33 by any of these methods as well. The securement of the base plate 33 to the boom can be either a permanent securement or a detachable securement.
The foregoing is offered primarily for purposes of illustration. Further variations in the contours, shapes, and relative dimensions and sizes that are still within the scope of the invention will be apparent to those skilled in the art.
