Handling: hand and hoist-line implements – Grapple – Pivoted jaws
Patent
1998-03-09
2000-10-17
Kramer, Dean J.
Handling: hand and hoist-line implements
Grapple
Pivoted jaws
294 88, 294902, B66C 128
Patent
active
061319783
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a grapple for a skidder used in the logging industry. In particular, it relates to a grapple tong and an attachment for a grapple tong.
BACKGROUND OF THE INVENTION
Skidders are used in the logging industry for transporting or sorting logs by pulling them along the ground. This is achieved by a grapple on the skidder which comprises a pair of opposed tongs which grips the log or logs for pulling along the ground. The tongs are pivotally mounted members which are hydraulically or cable operated for moving towards and away from one another in order to effect the gripping action. The grapple is located at the end of a boom which can be raised or lowered by hydraulic or cable means.
A grapple can be used to transport a bundle of logs in which case the grapple is used to clamp all the logs between the tongs, or it can be used in applications where single or smaller diameter logs are transported. A problem which arises in the latter type of application is that the tongs of some grapples do not come close enough together when closed in order to effectively grip a log. A further problem which arises is that grapples which are designed for gripping a bunch of logs, referred to as bunching grapples, have a relatively long opening and closing time making them very time consuming to open and close for a single log or broken tree.
It is accordingly an object of the present invention to alleviate the above difficulties.
SUMMARY OF THE INVENTION
According to the invention there is provided a grapple comprising a pair of opposed tongs which are movable toward or away from one another about respective pivotal axes, each tong terminating in a grapple prong for gripping objects between the grapple prongs, characterized in that each tong is provided with a secondary prong thereon, which secondary prong is radially offset from the grapple prong with respect to the pivotal axis.
Further according to the invention there is provided a grapple tong comprising an elongate member terminating in a grapple prong and having a connecting formation thereon for connecting the grapple tong to a grapple head for pivotal movement about a pivotal axis, characterized in that the tong is provided with a secondary prong thereon, which secondary prong is radially offset from the grapple prong with respect to the pivotal axis.
Also according to the invention there is provided an attachment for a grapple tong which grapple tong comprises an elongate member terminating in a grapple prong and having a connecting formation thereon for connecting the grapple tong to a grapple head for pivotal movement about a pivotal axis, characterized in that the attachment comprises a base provided with a projection thereon for attachment to the grapple tong along the base, whereby the projection forms a secondary tong on the grapple tong which is radially offset from the grapple prong with respect to the pivotal axis.
Other objects and advantages of the invention will become apparent from the description of a preferred embodiment of the invention below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of examples, with references to the accompanying drawings, in which:
FIG. 1A is a three-dimensional view of a pair of tongs according to the invention, shown in dissembled condition;
FIGS 1B to 1D, respectively, show side views of the tongs of FIG. 1A assembled in a grapple, with the tongs in a fully open position, a semi-closed position, for gripping a bundle of logs, and a closed position for gripping a single log;
FIG. 2 is a three-dimensional view of a pair of tongs according to another embodiment of the invention, shown in dissembled condition;
FIG. 3 is a three-dimensional view showing a conventional grapple tong and a tong attachment according to the invention;
FIG. 4A is a three-dimensional view showing a conventional grapple tong and a tong attachment according to another embodiment of the invention;
FIG. 4B shows the tong of FIG. 4A with the tong attachment according to th
REFERENCES:
patent: 1346160 (1920-07-01), Barlow
patent: 2740210 (1956-04-01), Hamborg
patent: 3082031 (1963-03-01), Lindberg
patent: 3904232 (1975-09-01), Byles
patent: 4993914 (1991-02-01), Riddle
de Kock Elbie R.
Kramer Dean J.
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