Handling: hand and hoist-line implements – Hook – hoistline – or grab type – Locking device
Reexamination Certificate
1998-11-16
2001-01-23
Kramer, Dean J. (Department: 3652)
Handling: hand and hoist-line implements
Hook, hoistline, or grab type
Locking device
C294S104000, C414S740000
Reexamination Certificate
active
06176531
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to grappling systems for securing and lifting heavy cargo or loads, and more particularly to a grappling system that is easily mounted to a front-end loader or other equipment.
BACKGROUND OF THE INVENTION
It has been known to provide a grapple attachment which mounts to the bucket of a front loader-type tractor, such as that previously disclosed in U.S. Pat. No. 4,285,628. Such grapple systems typically include an upper, movable jaw member which is hinged so as to generally pivot or rotate about a horizontal axis between an open and closed configuration relative to the fixed bucket assembly. By swinging from an open to a closed configuration, the movable jaw member is able to trap and pin the target load within the mouth of the bucket. Once securely pinned within the bucket, the load may be lifted and transported to the desired destination.
In previous grapple designs, the actuating mechanism for controlling the position and relative orientation of the movable jaw member with respect to a stationary jaw assembly typically incorporates a direct linkage between a point on the fixed jaw assembly and a corresponding point on the pivoting jaw member. Generally, the direct linkage assembly includes a linear actuating power unit such as a hydraulic cylinder, which is physically located between the fixed jaw assembly and the pivot axis of the movable jaw member. The hydraulic cylinder, being so positioned, is capable of extending and contracting the effective length of the connecting linkage, thereby causing the movable jaw member to generally rotate about the horizontal pivot axis between an opened and closed configuration. As a consequence of this type of connecting linkage and actuation configuration, there are certain orientations of the jaw member which render the actuating mechanism with a very short effective lever arm, and hence very little mechanical advantage. While in such orientations, the resultant force ultimately transferred to the movable jaw member is quite small, because of the short lever arm, and as a consequence large, powerful actuators and associated heavy structural support members are often required to accommodate a broad or full range of grapple jaw movement.
Therefore, with particular regard to grapple assemblies which are adapted to be mounted and secured to a front-end loader or equipment adapted to carry a grapple, there is and continues to be a need for a grappling assembly that incorporates an actuating mechanism which is capable of maintaining a significant mechanical advantage over a broad range of grapple jaw movement, thereby reducing actuating power requirements and actuator related structural requirements.
SUMMARY OF THE INVENTION
The present invention entails a grapple system that includes an attaching frame and a jaw assembly mounted to the attaching frame. The jaw assembly includes a stationary jaw section and a movable jaw section. A shaft interconnects the stationary jaw section with the movable jaw section. There is provided an interconnecting linkage that is connected between the movable jaw section and a fixed point, which in a preferred embodiment is a fixed point associated with the stationary jaw section. The interconnecting linkage includes a pair of hydraulic cylinders interconnected by a rotating connecting link, the rotating connecting link being rotatable about the axis of the shaft that interconnects the stationary jaw with the movable jaw. In order to open and close or move the movable jaw, the hydraulic cylinders are actuated through a hydraulic control system. In the design shown herein, the extension of the two hydraulic cylinders results in the movable jaw being moved towards a closed position while the retraction of the hydraulic cylinders results in the movable jaw being moved towards an open position relative to the stationary jaw. At certain points in the opening and closing cycle, one cylinder may enjoy a more favorable mechanical advantage than another hydraulic cylinder. In such cases, the hydraulic cylinder enjoying the more favorable mechanical advantage will be extended or retracted while the others cylinder may remain, during this portion of the cycle, static, in which case the static cylinder simply serves as a connecting link.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.
REFERENCES:
patent: 2875913 (1959-03-01), Gohrke et al.
patent: 3119637 (1964-01-01), Eaves
patent: 3152706 (1964-10-01), Conrad
patent: 3194421 (1965-07-01), Lull
patent: 3203566 (1965-08-01), Kampert et al.
patent: 3356238 (1967-12-01), Aldred
patent: 3637250 (1972-01-01), Blonsky
patent: 4106646 (1978-08-01), Weisgerber
patent: 4280777 (1981-07-01), Gray
patent: 5078569 (1992-01-01), Cook
patent: 5518359 (1996-05-01), Pratt
patent: 1320-161 (1987-06-01), None
Coats & Bennett PLLC
Kramer Dean J.
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