Cutlery – Cutting tools – Plural cooperating blades
Reexamination Certificate
1999-07-26
2001-10-23
Payer, Hwei-Siu (Department: 3724)
Cutlery
Cutting tools
Plural cooperating blades
C030S135000, C030S271000
Reexamination Certificate
active
06305086
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to tools used for repairing electronic systems, and, in particular, to electronic pin cutoff tools.
BACKGROUND OF THE INVENTION
Just as electronics systems are ubiquitous in the modern world, conductive pins used to carry signals are ubiquitous in electronic systems. Conductive pins may extend from a printed circuit board, such as a personal computer “motherboard”, where they may be employed as “jumpers” to effect semi-permanent electronic configuration settings, for example. Additionally, such pins are also frequently employed on the backplanes of an electronics systems' card cage. The backplane is itself typically a printed circuit board whose conductive traces interconnect the various signal lines brought into the backplane's edge connectors from the electronics cards plugged into the backplane's edge connectors. That is, printed circuit boards housing system electronics and fitted with edge connectors plug into connectors on such backplanes. On the opposite side of the backplane from the edge connectors, protruding conductive pins make electrical connection with the signal lines within the backplane edge connector, thereby “bringing out” these signals to the back side of the backplane. These conductive pins are typically arranged in an array of closely spaced rows and columns and are used, for example, to test and monitor the electronics housed within the card cage.
Sometimes, in order to repair or otherwise modify the electronics system, these pins must be removed. Specialized tools, pin cutoff tools, are used to cut the pins. Pin cutoff tools typically are of a pliers-like construction, having handles which, when forced together, apply a leveraged force to pincer tips on the opposite side of a pivot point from the handles. When closed over a pin, the pin is cut off by the pinching action of the pincer tips.
Because the pins are typically positioned very close to one another on the circuit board, getting the pin cutoff tool properly positioned is a difficult proposition. Consequently, neighboring pins are often inadvertently bent or broken, thus requiring their own replacement and compounding the problem that the pin cutoff tools was intended to solve. Additionally, since a great deal of force must be brought to bear in order to clip the pins off in the pincer tips, the pins often fly off, caroming into sensitive electronics equipment.
A pin cutoff tool that cuts targeted pins without damaging neighboring pins, and that does so while substantially reducing the likelihood that a cut pin will be ejected into neighboring electronics equipment would therefore be highly desirable.
SUMMARY
A pin cutoff tool in accordance with the principles of the present invention employs shears, rather than pincers, to sever pins. The pin cutoff tool is formed in a pliers-like configuration, with working surfaces formed within the jaws, and a pair of handles situated in working arrangement opposite a pivot point to provide leveraging advantage to the shearing surfaces. The shearing surface elements are arranged laterally, that is orthogonal to the lengthwise axis of the tool and parallel to the interior surfaces of the jaws.
In an illustrative embodiment stops are formed within the jaws of the tool to prevent over-travel. Additionally, a stop, such as a nut and bolt, or rivet, arrangement, may be employed to limit the amount which the jaws may be opened, thereby reducing the likelihood of damaging pins situated near the pin being trimmed. The jaws may be formed to have a relatively narrow opening such that, when closed, the sheared pin will be less likely to be ejected from the jaws of the tool than if the interior opening were wider. In another aspect of the invention, a substance may be applied to the interior surfaces of the jaws to further reduce the likelihood that the pin will be ejected. Such a substance may be a resilient, cushioning material, such as rubber or foam, and may also provide an adhesive surface to capture the sheared pins. Grooves may be formed in the jaws to accommodate neighboring, closely situated pins, and, to further facilitate the use of the tool in cramped quarters, the jaws may be relatively narrow, so that neighboring pins in a direction orthogonal to the plane of the channels are not disturbed
REFERENCES:
patent: 29543 (1860-08-01), Baker
patent: 483869 (1892-10-01), Randle
patent: 881092 (1908-03-01), Broadbooks
patent: 908969 (1909-01-01), De Arment
patent: 1349563 (1920-08-01), Day
patent: 1399958 (1921-12-01), Gilbert
patent: 3091853 (1963-06-01), Polayes
patent: 3352010 (1967-11-01), Keller
Lucent Technologies - Inc.
Payer Hwei-Siu
Wiegard James W
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