Wireworking – Joining wire – Implements
Reexamination Certificate
2000-01-18
2001-08-07
Larson, Lowell A. (Department: 3725)
Wireworking
Joining wire
Implements
C140S124000
Reexamination Certificate
active
06269845
ABSTRACT:
BACKGROUND OF THE INVENTION
Wire wrapping tools are well known in the art and are commonly used nowadays for the making of connections to terminals on a printed circuit board (PCB). See, for example, U.S. Pat. Nos. 4,177,555 and 4,194,700, whose contents are herein incorporated by reference, as examples of such tools. The wrapping tool wraps the wire around a sharp-cornered terminal which crushes any oxide layer between the terminal and wire and providing a tightly-held oxide-free metal-to-metal contact of the wire to the terminal. The typical tool is a wire-wrapping gun containing what is known as a removable bit and sleeve. The latter is typically fixed, and the bit rotates, usually clockwise (CW), within the sleeve. Wire from a spool, for example, is fed through the sleeve to the bit face. The bit has a bore for receiving the terminal, and when the bit is rotated around the terminal, structure on the bit face grabs the wire and wraps it around the terminal. The bit and sleeve are replaceably held on the tool by a front-facing collet which when tightened holds the sleeve within the tool. The bit is held in place within the sleeve by a shoulder on the bit. Replacement of the bit and sleeve is accomplished by loosening of the collet to release the bit and sleeve so it can be removed and replaced. Reasons for replacing include wrapping on a different size of terminal.
Tools also exist for unwrapping a wrapped wire from a terminal. A typical tool has a spiral groove cut into the end of an unwrap bit. When the unwrap bit is rotated counterclockwise (CCW) on the terminal, the bit face grabs the end of the wire and feeds it into the spiral groove allowing it to be unwrapped from the terminal. See U.S. Pat. No. 4,064,581, whose contents are herein incorporated by reference, which describes a hand tool having a wrapping bit at one end and an unwrapping bit at the opposite end. Using a gun-type power tool for wrapping and unwrapping requires that a first bit and sleeve is used for wrapping, and to unwrap the first bit and sleeve must be removed and replaced by an unwrap bit and sleeve that acts as a bushing for the bit, and the power tool must be capable of both CW and CCW operation.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an improved tool capable of wrapping and unwrapping wires on terminals.
Another object of the invention is a tool provided with a quick-release mechanism to allow rapid and simple replacements of bits and sleeves.
Still another object of the invention is a novel bit/sleeve combination capable of wrapping wires on terminals when rotated in one direction and unwrapping wires from terminals when rotated in the opposite direction.
In accordance with a first aspect of the invention, the tool of the invention features a quick-release for the bit/sleeve.
In a preferred embodiment, a bit driver comprises an outwardly facing concave surface that cooperates with a collet having a tapered split end adapted to engage the concave surface and held in loose engagement therewith by a biasable collet housing in a first position. When the collet housing is moved to a second position, it is biased toward the collet and the collet's tapered split end is cammed by the concave surface into a gripping relationship with a sleeve tightly holding the sleeve on the tool while the bit is driven. To release the bit and sleeve it is merely necessary to move the collet holder from its second to its first position, which preferably is accomplished by rotation of the holder no more than 30°.
In accordance with a second aspect of the invention, the tool of the invention features a motor reversing switch for allowing the tool to be used both for wrapping and for unwrapping wires.
In a preferred embodiment, the reversible switch is located in a protected region at the rear of the tool to prevent accidental activation.
In accordance with a third aspect of the invention, the tool of the invention features a novel bit/sleeve construction that allows the same combination to be used for unwrapping or for wrapping wires without having to replace the bit or sleeve.
In a preferred embodiment the combined wrap/unwrap bit/sleeve comprises a bit having a bit face that will wrap around a terminal a wire fed to it through the sleeve and also provided adjacent the bit face with a helical groove capable when exposed of unwrapping a wrapped wire, a sleeve within which the bit rotates, and an adaptor or sleeve extension surrounding the sleeve and cooperating with the sleeve to hold it in either if two positions, a first position when the sleeve projects forward over the bit face and surrounding the helical groove and can provide the usual sleeve function of feeding a wire to the bit face during wrapping, and a second position when the sleeve is moved rearward to expose the helical groove allowing it to carry out its unwrap function.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components.
REFERENCES:
patent: 3070380 (1962-12-01), Holmberg
patent: 3403440 (1968-10-01), Omori et al.
patent: 3440465 (1969-04-01), Pratt et al.
patent: 3799561 (1974-03-01), Humbert
patent: 4835410 (1989-05-01), Bhagwat et al.
patent: 5245749 (1993-09-01), Couch, Jr.
Baykov Sergey
Bazayev Edward
Scirbona Edward
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