Tools – Wrench – screwdriver – or driver therefor – Pivoted side jaw
Reexamination Certificate
1998-03-06
2001-05-01
Morgan, Eileen P. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Pivoted side jaw
C081S090100
Reexamination Certificate
active
06223630
ABSTRACT:
BACKGROUND
This invention relates to ratchet wrenches, and more particularly to open-end ratchet wrenches that can be placed on a workpiece from the side.
There are many occasions when it is desirable to apply torque to a workpiece (such as nuts, bolts, and in-line hydraulic fittings) in order to, for example, rotate the workpiece with respect to a threaded member. Two well known tools for rotating workpieces are ratchet wrenches and open-end crescent wrenches. Ratchet wrenches are typically close-ended devices that completely encircle the workpiece and are thus installed on the workpiece from the top (or bottom, depending upon the orientation of the workpiece). By contrast, open-end wrenches can be installed from the side of the workpiece.
Open-end wrenches are particularly useful in small spaces where there may only be sufficient room to install the wrench from the side. Moreover, in confined spaces, there is often insufficient space to accommodate the ratchet mechanism of typical close-ended ratchet wrenches. In addition, open-end wrenches are a must for tightening/loosening in-line fittings of hydraulic or fuel lines, which can only receive a wrench from the side.
Typical open-end crescent wrenches lack a ratchet mechanism. As a result, during a tightening or loosening operation, the wrench must be removed from the workpiece after it has rotated the workpiece a relatively small amount (such as 30 degrees), and then replaced thereon at a different angle for continued rotation. This procedure is repeated (often many times) until the workpiece is completely tightened or loosened.
Open-end ratchet wrenches that resemble typical crescent wrenches have been developed for confined and in-line fitting applications. Some open-end ratchet wrenches employ numerous spring-loaded rollers, cams, or pawls for engaging the workpiece; others use an insert shaped to fit over the workpiece and engage an internal ratchet mechanism. Some of these wrenches encircle the workpiece to such an extent that, even though the wrenches have open ends, they must actually be installed vertically from above or below the workpiece.
Another open-end ratchet wrench, described in my U.S. Pat. No. 5,456,143, includes a pair of elongated plates that are pivotally mounted to a pair of spaced jaws on the wrench handle. A spring mounted on the handle engages the plates and biases them toward each other so that the plates grasp and turn the workpiece when the handle is rotated in a driving direction. The spring bias is overcome when the handle is turned in the opposite direction, allowing both plates to pivot on the jaws and slide over the faces of the workpiece in a ratcheting manner.
SUMMARY
This invention features, in a general aspect, a wrench having a pair of jaws disposed on a handle and spaced to define an opening for a workpiece, and a pair of plates each of which includes a workpiece engaging surface adjacent the opening; the plates are mounted on the jaws for selective movement between: a) a first position in which the plates are immobile with respect to each other so that rotation of the handle in a first direction causes the plates to grasp the workpiece between the engaging surfaces and turn the workpiece in the first direction, and b) and a second position in which a first one of the plates is pivotable with respect to a second one of the plates so that rotation of the handle in a second, opposite direction causes pivoting of the first plate and allows the engaging surfaces to slide over the workpiece, thereby allowing the workpiece to remain stationary. Thus, the wrench tightens (or loosens) the workpiece when rotated in the first direction, and slips over the workpiece in a “ratcheting” manner when rotated in the second, opposite direction.
The invention unites features of an open end wrench and a ratchet wrench in a wrench that is rugged and simple to make. The wrench has a minimal number of moving parts and thus is much easier to manufacture (and repair) than wrenches which use many individual pawls or rollers to provide ratcheting. In preferred embodiments, the plates each engage the workpiece over a relatively large surface area, thereby maximizing torque transmission and minimizing contact stresses imposed on the wrench and the workpiece. This reduces the risk of damage to the wrench and the workpiece.
The spacing between the jaws and the configuration of the elongated plates permit the plates to operate the workpiece while engaging only four faces of the workpiece and encircling the workpiece through an arc of only 240 degrees. As a result, the wrench can easily be inserted onto and removed from the workpiece from the side for ease of use in cramped spaces. In preferred embodiments, the ratcheting operation is assisted by a spring which biases one of the plates toward the opening, which makes turning the workpiece fast and easy while requiring no clearance behind the workpiece.
Preferred embodiments may include one or more of the following additional features.
The plates are mounted for the selective movement in response to rotation of the handle. No separate locking or unlocking mechanism is needed to change the operating state of the wrench. For example, after turning the workpiece in the first direction, the wrench is simply rotated in the opposite direction to move the plates to the second position for ratcheting.
The first plate is mounted to a first one of the jaws so that the distal end of the plate is immobile in the first position, and is pivotable with respect to the second plate in the second position. A distal pin on the distal end of the first plate is received by a slot disposed in a distal region of the first jaw. The distal pin is disposed in a first portion of the distal slot when the plate is in the first position, and is disposed in a second portion of the distal slot when the plate is in the second position.
The first portion of the distal slot is oriented so that the engagement of the distal pin therein holds the distal end of the first plate immobile with respect to the second plate when the wrench is rotated in the first direction, and the second portion of the distal slot is oriented to allow the distal end of the first plate to pivot with respect to the second plate when the wrench is rotated in the second direction.
A proximal pin on the proximal end of the first plate is received by a slot disposed in a proximal region of the first jaw. This proximal slot and the first portion of the distal slot are oriented (preferably along a common arc of curvature) to allow the selective movement of the first plate between the first and second positions. The center of the common arc of curvature is disposed in the opening. The second portion of the distal slot is arranged transversely to the arc of curvature.
The proximal pin is also mounted to the proximal end of the second plate. A distal pin at a distal end of the second plate is received by a slot disposed in a distal region of the second jaw. This distal slot is, with the proximal slot, oriented to allow the selective movement of the second plate between the first and second positions.
The plates and the spring are arranged so that turning the wrench over with respect to the workpiece reverses operation of the wrench in the first and second directions. That is, with the wrench turned over, the wrench tightens or loosens the workpiece when rotated in the second direction, and produces the ratcheting action when rotated in the first direction.
The plates are identically configured. This significantly simplifies manufacture and, along with the manner in which the plates are movably mounted to the jaws renders the wrench easily scalable in size. Each plate preferably has a plurality of the engaging surfaces, and each surface is elongated so as to engage a face of the workpiece over a major portion of a length of the face. The engaging surfaces are flat. The engaging surfaces are arranged to define an angle therebetween equal to an angle between adjacent faces of the workpiece.
Other features and advantages of the invention will
Danganan Joni B.
Fish & Richardson P.C.
Morgan Eileen P.
LandOfFree
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