Patent Application
20130140836
No related application.
1. Field of Disclosure
This disclosure relates generally to a post driver with grapple mechanism, and more particularly, to a grapple member on a post driver which is biased toward a generally horizontal position at rest, but which rotates into a generally vertical position suitable for post-driving when a post is grappled.
2. Background Art
Post drivers that utilize the pile driving principle of raising a weight to some distance above a post and then dropping the weight in order to drive the post rely heavily upon the skill of the operators to properly position the post and post driver in the correct position. Indeed, many post drivers require at least two operators—one to position the post and another to operate the skid-steer and the post driver itself. When a post is properly positioned within the post driver, the kinetic energy of the falling might is transferred into the post, pushing it into the ground. However, when a post is not properly positioned within the post driver, various issues may arise. The weight may fail to contact the post upon falling, and may instead impact upon the frame of the post driver (a dry fire), or the post may be extend too far into the post driver such that the overall driving performance of the driver is reduced due to a shorter stroke length. Additionally, the use of two operators creates inefficiencies and slowdowns, and puts the operator in charge of positioning the post in a position of some danger.
Hydraulic grapple mechanisms have been added to some existing devices to reduce the number of operators necessary to drive posts. Generally, such mechanisms include hydraulics for actuation of the grapple, as well as for swinging the grapple mechanism into and/or out of proper alignment with the post driver. Additionally, most such grapple mechanisms are located on the front of the housing of the post driver, creating two problems. First, when swinging from a horizontal to a vertical position, the post is angled directly at the operator in the skid-steer. If the post slips out of the grapple mechanism, it will fell toward the skid-steer and the operator. Second, this positioning puts the post driver in between the operator and the post, making it hard for the operator to see what is happening.
The post driver includes a grapple mechanism which is connected to the post driver on one side, rather than in the front of the post driver. The grapple connects to the post driver via a hinge which allows substantially 90 degrees of rotation between a horizontal position for picking up posts, and a vertical position for driving the post into the ground. A biasing mechanism such as a spring or counterweight preferably biases the grapple mechanism toward its horizontal position. However, the biasing mechanism is prefer ably not so strong as to hold the grapple mechanism in the horizontal position even when a post is grappled. Preferably, the weight of a grappled post is sufficient to overcome the biasing mechanism, causing the grapple mechanism to pivot about the hinge and into the vertical position. The grapple mechanism is therefore preferably sized, shaped and weighted so as to swing to a substantially vertical position when a post is grappled and lifted.
The jaws of the grapple are preferably actuated by hydraulics or other suitable mechanisms, and are preferably geared rotatable jaws to rotate open and closed rather than a sliding jaw. Sliding jaws tend to limit the range of post size and weight that can be effectively grappled, whereas geared rotatable jaws allow for a broader range of post sizes and weights while using fewer components.
Accordingly, an aspect of the present disclosure is a post driver comprising a main housing, a grapple mechanism rotatably attached to the housing, the grapple mechanism including geared rotatable jaws, and a biasing mechanism associated with the grapple mechanism, wherein the biasing mechanism allows for rotation of the grapple mechanism when the grapple mechanism is grappled with a post, but which mechanically prevents rotation of the grapple mechanism when the grapple mechanism is not grappled with a post.
In another embodiment, an aspect of the present disclosure is a grapple mechanism rotatably attached, to a post driver about a pivot point, the grapple mechanism comprising rotatable jaws, gears for rotating the jaws, a grapple housing supporting the jaws and gears, and a biasing mechanism structured to bias the grapple mechanism in a generally horizontal position when at rest, but having an insufficient bias to maintain the grapple mechanism in the generally horizontal position when the rotatable jaws grapple and lift a post.
In another embodiment, an aspect of the present disclosure is a post driver comprising a main housing, a grapple housing pivotally connected to a side of the main housing other than a front side, and hydraulically actuated geared rotatable jaws associated with the grapple housing, wherein pivoting of the grapple housing about a pivot point positions the geared rotatable jaws underneath the main housing from the side of the main housing.
For a better understanding of the present disclosure, reference may be made to the accompanying drawings in which:
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawing and will herein be described in detail. If should be understood, however, that the drawings and detailed description presented herein are not intended to limit the disclosure to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives felling within the spirit and scope of the present disclosure as defined by the appended claims.
Referring to
As shown in
Gears 14 and jaws 16, 18 are secured to a grapple housing 24. The grapple mechanism 10 is preferably attached to the post driver 1 via the grapple housing 24. As shown in
When, the grapple mechanism 10 is at rest, the grapple housing 24 is preferably biased by a biasing mechanism, shown in
In operation, the post driver 1 with the grapple mechanism 10 in its horizontal position is lowered to grapple a post 3, As shown in
Once the jaws 16, 18, are positioned around tire post 3, the operator uses the hydraulics to close the jaws 16, 18 around the post 3. The hydraulics, via hydraulic lines 12, cause the gears 14 to rotate so as to rotate the jaws 16, 18 into a closed position which either pinches the post 3 or closes around the post, depending on the size of the post 3. Having secured the post 3 in the jaws 16, 18, the post driver 1 can be lifted back up toward its post driving position. As the post driver 1 is lifted, the grapple mechanism lifts the post 3. As the weight of the post 3 begins to be carried by the grapple mechanism 10, the biasing spring 22 is no longer capable of holding the grapple mechanism 10 in its horizontal resting position. The weight of the grapple mechanism 10 in combination with tire weight of the post is sufficient to overcome the tension of the spring 22, and the grapple mechanism. 10 pivots about pin 20.
Thus, the weight of the post 3 causes the grapple mechanism 10 to swing into its vertical position, shown in
Additionally, by positioning the grapple mechanism 10 to one side of the post driver 1 rather than at its front, when the post 3 swings from its resting horizontal position into a vertical position for driving, the post 3 is never angled at the operator of the skid-steer. If the post 3 were to slip horn the jaws 16, 18, the post 3 would merely fall to one- side of the post driver 1, rather than back toward the operator.
In another embodiment, the biasing mechanism: which biases the grapple mechanism 10 toward a position generally parallel with the ground may not be an additional component at all. The biasing mechanism may instead be the size, shape, and weight distribution of the grapple mechanism 10 itself including jaws 16, 18. In such an embodiment, the weight distribution of the grapple mechanism 10 itself may be designed so as to cause the grapple mechanism 10 to reside in its generally horizontal position (parallel with the ground) when no post is grappled, but which swings into a substantially vertical position when a post is grappled and lifted.
As is evident from the foregoing description, certain aspects of the present disclosure are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. It is accordingly intended that the claims shall cover all such modifications and applications that do not depart from the spirit and scope of the present disclosure. Moreover, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. Although any methods and materials similar to or equivalent to or those described herein can be used in the practice or testing of the present disclosure, the preferred methods and materials are described above. Other aspects, objects and advantages of the present disclosure can he obtained from a study of the drawings, the disclosure and the appended claims.
