Tools – Wrench – screwdriver – or driver therefor – Sliding jaw – cam-closing
Reexamination Certificate
1999-01-25
2001-03-27
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Sliding jaw, cam-closing
C081S309000
Reexamination Certificate
active
06205892
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates in general to an adjustable wrench, and in particular to a ratcheted adjustable bolt wrench. Still more particularly, the present invention relates to an adjustable, three-jawed wrench that is ratcheted, to be used for any size hexagonal bolt.
2. Description of the Prior Art:
Bolt wrenches are an old art. There are primarily three general types of wrenches: socket wrenches, fixed end wrenches, and adjustable wrenches. In each type of wrench, there are several common ideal features. The wrench should be easy to use, since one-handed applications may be necessary in practice. Second, the head of the wrench, the section of the wrench that actually grips a bolt, must be able to grip the bolt in such a way that the corners of the standard hexagonal bolts are not stripped. Once stripped, the bolts become very difficult if not impossible to work with, and must be mechanically cut and replaced.
Of the three basic types of wrenches in current use, adjustable wrenches offer the most versatility. Further, adjustable wrenches are easier to use than socket or fixed end wrenches, both of which require the user to either replace the socket for different applications or change out the entire wrench. This is time consuming and tedious in working conditions. An adjustable wrench allows the user to adjust a single tool unit to the various shapes and sizes of bolts, both metric and standard.
The only drawback to adjustable wrenches is their gripping ability. Specifically, adjustable wrenches currently available are not able to fit a bolt as snugly as socket of fixed end wrenches. This often leads to stripping of the bolt head, which further complicates the loosening or tightening of a bolt. Generally, the advantage that socket and fixed end wrenches have in this regard is an increased contact area with the bolt head. Socket and fixed end wrenches are typically designed to contact each of the six corners of the bolt head as well as each side. The greater the contact area, the tighter the fit between the wrench and bolt. Thus, what is needed is a wrench that has the versatility of an adjustable wrench, but also the advantages of fixed and socket wrenches.
Most adjustable wrenches have two bolt claws that are adjustable relative to each other to contact the bolt head, typically on two opposing sides of the hexagonal bolt. Increasing the number of sides contacted, and the number of corners contacted would be ideal. This could be accomplished by increasing the number of bolt claws on the adjustable wrench, thus increasing the surface area of the bolt head contacted. There are pliers in the art that have such a feature. For instance, the Stallings (U.S. Pat. Nos. 1,250,690 and 1,498,488) inventions are pliers with two opposing claws, with a third pivotally mounted claw located central to the other two. The claw contact region is a complex structure, and the use of these pliers is directed towards general gripping of rounded surfaces such as pipes. These devices would not be suitable for a bolt wrench.
There are several other inventions directed towards an adjustable wrench. The Whelan (U.S. Pat. No. 1,401,931) invention is an adjustable pipe wrench that uses two opposing complex surfaced claws for gripping a pipe, with a third attachment coupled in such a manner to allow both parts to slide and pivot, increasing the contact surface area of the pipe being gripped. The Wei (U.S. Pat. No. 5,542,319) invention is an adjustable bolt wrench using two opposing bolt claws with a ratcheted handle. Although an improvement on the prior art, these two devices are either not directed towards a bolt wrench, or do not incorporate the advantages of fixed end wrenches by increasing the contact area of the bolt head and wrench. Thus, there is a need for a wrench that incorporates the ease of use of an adjustable wrench with the advantages of fixed end and socket wrenches.
SUMMARY OF THE INVENTION
An object of this invention is to provide a wrench that is easily adjustable in working conditions to various sized bolt heads.
Another object of the present invention is to provide an adjustable wrench with increased surface area contact between the bolt head and the contact portion of the adjustable wrench.
Another object of the present invention is to provide an adjustable wrench with a ratcheted operation to increase the ease and efficiency of use.
Another object of the present invention is to provide an adjustable wrench that has a specifically fitted bolt claw structure that will grip at least two of the bolt head sides and three equally spaced corners.
Additional objects, features and advantages will be apparent in the written description which follows. The invention is an adjustable wrench comprising a stationary arm with a terminal end and a grip end, the terminal end defining a lower bolt claw. A ratchet arm is coupled to the stationary arm, the ratchet arm being movable to control the movement of upper, lower and central bolt claws. The upper, central, and lower bolt claws define a fitted opening which forms a portion of the shape of a standard hexagonal bolt head, the fitted opening being adjustable to fit different sized bolt heads upon movement of the ratchet arm relative to the stationary arm.
The central bolt claw is fitted through a slot in the upper bolt claw which defines an inclined ramp surface such that movement of one claw is coupled to movement of the other claw. The central and upper claws move in unison in reaction to the stationary arm and lower bolt claw to form a tightly fitted surface for a bolt head. The stationary arm has a complex profile on its lower surface for contact with a ratchet pawl pivotally attached to the ratchet arm. The ratchet arm, having a grip end and a proximal end, is coupled to the central bolt claw at the proximal end. The ratchet arm is normally biased away from the stationary arm by a biasing spring, being manually pushed away from the stationary arm during adjustment of the wrench to a bolt.
Further, the central bolt claw is formed to fit an additional corner of a hexagonal bolt. The grip ends of the ratchet and stationary arms are held by the user in one hand to operate the single unit wrench. This configuration allows simplicity of use and improved gripping ability for standard hexagonal bolt heads.
REFERENCES:
patent: 680540 (1901-08-01), Ogle
patent: 1250690 (1917-12-01), Stallings
patent: 1401931 (1921-12-01), Whelan
patent: 1498488 (1924-06-01), Stallings
patent: 2592098 (1952-04-01), Zimdars
patent: 3195381 (1965-07-01), Meggs
patent: 5249490 (1993-10-01), Kennel
patent: 5542319 (1996-08-01), Wei
Gunter, Jr. Charles D.
Smith James G.
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