Self adjusting utility pliers

Details Self adjusting utility pliers Self adjusting utility pliers

2000-01-14

2001-11-06

Eley, Timothy V. (Department: 3723)

Tools

Tool jaw

Adjustable relationship between jaw

C081S407000, C081S408000, C081S411000, C081S392000

Reexamination Certificate

active

06311588

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to utility pliers and, more particularly to self-adjusting pliers that can be locked in a storage position and released to an operating position capable of grasping a workpiece.
BACKGROUND OF THE INVENTION
Many types of handheld utility pliers are known in the art. Conventional pliers typically include two rigid plier members interconnected in a scissors-like arrangement allowing for a workpiece to be grasped by jaw portions of the pliers in response to movement of handle portions of the pliers. Over the years, numerous improvements have been made to the conventional plier design in order to obtain a better and more efficient plier. For example, self-adjusting pliers have been developed in order to provide a set of pliers that more easily adjust to the size of a given workpiece.
A basic feature of self-adjusting pliers, such as those disclosed in application Ser. No. 09/108,561, hereby incorporated by reference, is that they provide two rigid structures having respective handle portions and jaw portions, a rack engagement structure mounted on one of the rigid structures, and a rack provided on the other rigid structure.
In these types of pliers, however, when there is an absence of a workpiece between the jaw portions and manual force is applied to the handle portions toward one another, the jaw portions eventually engage one another and then frictionally rub against one another as the rack engagement structure moves toward the rack and until the rack engagement structure engages the rack. Because users may have a tendency to work the tool without a workpiece between the jaw portions (e.g., to test the tools prior to a clamping operation), the point of engagement between the jaw portions tends to be a primary area of wear. In addition, the relative movement between the contacting jaw portions may cause some misalignment between the jaw tips during some points of operating the tool, which may be undesirable from a cosmetic point of view.
In addition, the self-adjusting pliers in the aforementioned incorporated Application have handle members that are spring biased apart. Thus, when the tool is not being used, the handle members are spread wide apart. As a result, such pliers occupy a relatively large amount of space when being stored. Thus, there exists a need to provide self-adjusting pliers that can be efficiently secured in a compact configuration for storage purposes.
SUMMARY OF THE INVENTION
It is the object of the present invention to fulfill the needs expressed above. In accordance with the principles of the present invention, this objective is accomplished by providing self-adjusting pliers comprising a first member providing a first handle portion and a first jaw portion and a second member providing a second handle portion and a second jaw portion. The first member defines a rack having a plurality of teeth, while a rack engagement structure is mounted to an intermediate portion of the second member and positioned adjacent to the rack. A spring structure is constructed and arranged to bias the first handle portion apart from the second handle portion into a fully opened position. The rack engagement structure is positioned relative to the rack such that during the initial manual movement of the first and second handle portions toward one another, the rigid structures pivot relative to one another. The rack engagement structure travels in disengaged, parallel facing relation with respect to the rack. The first member is connected to the second member such that, after the first and second jaw portions engage the opposing sides of the workpiece, continued manual movement of the first handle portion towards the second handle portion against the bias of the spring structure, will cause the rack engagement structure to move toward the rack until the rack engagement structure engages the rack. Continued application of manual force to the first handle portion towards the second handle portion causes the application of such force to the workpiece through the rack engagement structure. The rack engagement structure has a movement restrictive portion that is cooperable with the rack so as to limit the movement of the rack engagement structure toward the rack when the jaw portions contact one another in the absence of a workpiece therebetween, which reduces friction between the jaw portions when the jaw portions contact one another in the absence of a workpiece therebetween.
An objective of the present invention is also achieved by providing a selfadjusting pliers comprising a first member that provides a first jaw that has a first workpiece engaging surface and a first handle member and a second member that provides a second jaw opposing the first jaw and a second handle member opposing the first handle member. The second jaw has a second workpiece engaging surface that faces generally towards the first workpiece engaging surface. A spring structure biases the handle members apart from one another. The first and second jaws are operatively connected to the handle members such that manually moving the handle members towards one another against the bias of the spring structure moves the jaws towards one another in a closing direction to move the workpiece engaging surfaces towards one another for grasping a workpiece. The spring structure is constructed and arranged to move the jaws apart from one another in an opening direction towards and into a fully opened position when the handle members are manually released. The first member provides an engageable rack and the second member provides a rack engagement structure. The rack engagement structure and the engageable rack are constructed and arranged such that, when the rack engagement structure is engaged with the rack, movement of the handle members towards one another as aforesaid causes the handle members to pivot relative to one another about the rack engagement structure so as to continue moving the jaws toward another. The rack engagement structure and the engageable rack are positioned with respect to one another such that, as the jaws are being moved in the closing direction thereof to grasp a workpiece, the second member moves relative to the first member so as to engage the rack engagement structure with the engageable rack in response to the workpiece engaging surfaces of the jaws contacting opposing sides of the workpiece. A releasable lock is carried by one of the first and second members. The lock is manually movable between (a) a releasably locked position and a released position wherein, when the handle members have been moved toward one another into a fully closed position, the lock engages a structure on the other of the first and second members to prevent relative movement between handle members under bias of the spring structure and hence relative movement between the jaw portions, and (b) a released position wherein the lock is disengaged from the aforesaid structure to permit both relative movement between the handle portions and relative movement between the jaws.


REFERENCES:
patent: 4651598 (1987-03-01), Warheit
patent: 5660089 (1997-08-01), Chow
patent: 6000303 (1999-12-01), Chang
patent: 6101908 (2000-08-01), Azkona

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