Tractors and skid steers are common utility vehicles in the farming, construction and landscaping industries. The primary benefit of these vehicles is their great versatility and the wide variety of implements that can be attached to and used with the vehicle. After an initial investment in a tractor or skid steer, owners of these vehicles can add increased functionality by purchasing a wide variety of specialized implements including loaders, backhoes, blades, post hole diggers, forks and bale spears, to name a few. Because of the ubiquity and great versatility of tractors and skid steers, owners of these vehicles continuously seek new and improved implements to perform specialized tasks.
Pinching fingers are a good example of an implement that is especially useful for performing a specialized task. Pinching fingers are essentially claws that can be opened and closed around material or an item to be transported by the utility vehicle. Because the pinching fingers can be closed around the material or item, bulky and irregularly shaped items can be picked up and securely held while transported by the utility vehicle.
Although they have many uses, pinching fingers are especially useful for transporting logs and clearing brush. Pinching fingers can be clamped around a log so that the log cannot roll when it is picked up, transported and loaded, increasing the safety of working with large logs. Pinching fingers can also be easily clamped around irregularly shaped items such as fallen trees or heavy farm equipment, making it easier to lift and move such items than with conventional implements such as a bucket or forks.
Pinching fingers, however, are not easily adapted for use with conventional tractors or skid steers. Most tractors and all skid steers have arms extending from the front of the vehicle for the operation of a loader or other implements. These implements can be raised and lowered by hydraulic cylinders attached to each arm and also rolled forward and backward by a separate cylinder or cylinders. This range of movement (up, down, forward roll and backward roll) is sufficient for operating most common implements including loaders, blades, forks and spears. Thus, two sets of hydraulic controls, one for raising and lowering the implement and one for rolling the implement forward and backward, are standard on most tractors and skid steers. Pinching fingers, however, also requires means for opening and closing the pincer claws.
Prior art implements for pinching and grappling a load have been adapted for use with conventional tractors and skid steers. These implements typically utilize a third set of hydraulic controls (or other power means) for opening and closing the pincer claws or grappler. This solution, however, increases the cost of the implement because hydraulic cylinders, couplers and lines must be incorporated into the design of the implement. In the case of a tractor or skid steer that does not already have the necessary controls and lines installed, an entire hydraulic control and power system must be installed on the tractor or skid steer to use the implement. This added cost and complexity has prevented many potential users of pinching fingers and grapplers from adopting this useful implements. Thus, those of skill in the art have sought an implement that can be easily attached to a conventional tractor or skid steer without the need for separate controls and power means for opening and closing the implement.
In addition to the problem of requiring a separate set of controls, prior art designs have not been easy to install and remove on a conventional tractor or skid steer. To maximize the versatility and thus the utility of these vehicles, implements must be designed so that they can be quickly interchanged with other implements. Thus, those of skill in the art have sought pinching fingers with simple mechanical means for installing and uninstalling the implement on a conventional tractor or skid steer.
Prior art designs also typically suffer from another deficiency in their operation. To provide structural stability and strength, the top set of pincer claws on a conventional grappler are constructed as a unified or solid piece that clamps in opposition to and against a solid bottom set of pincer claws, forks or a bucket. When grasping an item of uniform cross section, this design is adequate for providing uniform pressure at each claw to secure the item. However, when a solid item to be grasped has a tapered or irregular cross section, one claw may be restricted from closing on the item when the other claw closes on a larger portion of the item, causing the item is held by only one claw and not the other. In this instance, the item cannot be safely transported without the danger of the item moving and shifting during transport. Thus, those of skill in the art have sought a grappler and/or pinching fingers with independent claws that can be closed on an item even if another claw is restricted from closing, but without sacrificing the structural stability or strength of the implement.
Accordingly, an object of the present invention is to provide pinching fingers for a tractor, skid steer or the like that can be used by the vehicle without the need for an additional set of controls and power means for opening and closing the pinching fingers.
A further object of the present invention is to provide pinching fingers that are easy to install and remove on a conventional loader or skid steer.
Yet another object of the present invention is to provide pinching fingers that can be quickly interchanged with other implements on a conventional loader or skid steer.
An additional object of the present invention is to provide pinching fingers that may move and grasp independently so that both claws securely grasp a solid item of tapered or irregular cross section.
A still further object of the present invention is to provide pinching fingers attachment with sufficient structural stability and strength to grasp, lift and transport heavy items including logs, trees and other items.
Still another object of the present invention is to provide an improved vehicle with a pinching fingers attachment.
Yet another object of the present invention is to provide an improved method for using a pinching fingers attachment with loaders, skid steers and the like.
A further object of the invention is to provide a loader or skid steer with pinching fingers that are simple and easy to operate.
Finally, an object of the present invention is to provide a pinching fingers attachment that is economical to manufacture, durable and refined in appearance.