Metal working – Method of mechanical manufacture – Disassembling
Reexamination Certificate
2000-03-20
2001-07-17
Watson, Robert C. (Department: 3723)
Metal working
Method of mechanical manufacture
Disassembling
C029S270000, C029S278000
Reexamination Certificate
active
06260253
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to tools for extracting inaccessible broken key ends from lock keyways, particularly automobile ignition locks, without damage or modification to the lock structure.
2. Description of the Related Art
It is not uncommon for the end portion of a key to break off in a lock keyway, particularly an automobile ignition lock utilizing tumblers. Such automobile locks usually constitute the primary electrical switch for the vehicle and employ the key to impose a torque on the switch once the key is properly inserted, and keys are often bent or otherwise stressed due to the forces imposed thereon during use.
When a portion of the automobile ignition key is broken off within the lock keyway or slot, such broken end is usually inaccessible, often prevents the ignition switch from being operated and renders the vehicle inoperative. Until the inaccessible broken key end portion is removed from the lock, operation of the vehicle is usually prevented.
Broken key extractors are known and such devices may use a variety of tools for endeavoring to coax the broken key end from the lock. Adhesives, hook probes, and the like, may be used. However, the difficulty encountered in removing broken keys from tumbler locks often is so great that the lock must be entirely replaced at considerable expense.
As of this date, easy to use, dependable apparatus for removing broken key portions from tumbler locks has not been available to the general public.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an extractor for removing broken keys from tumbler locks wherein the extractor tool is of a low cost, dependable, easy to use and relatively quick and may be operated by those having conventional mechanical skills.
Another object of the invention is to provide an extractor tool for removing broken key portions from tumbler locks wherein the extractor tool does no damage to the lock and its associated mechanism and permits the lock to be operated in the normal manner after key extraction.
Yet another object of the invention is to provide a method of extracting an inaccessible broken key portion from a tumbler lock keyway which can be practiced by persons of ordinary mechanical skill.
SUMMARY OF THE INVENTION
In the practice of the invention, a pair of thin deformable elongated retractor elements are inserted into a tumbler lock keyway or slot in such a manner as to grip an inaccessible key end located within the lock. Preferably, the practice of the method of the invention utilizes the accessible portion of the broken key, or a similar key blank, to be used as a guide for inserting the retraction elements into the lock, and into the grooves defined in the sides of the inaccessible broken key end. Once the accessible key portion is used to guide the extractor elements into the desired position, the accessible key portion is then removed from the lock. Thereupon, the retractor elements are twisted about each other causing the elements to twist within the lock and those portions of the retractor elements engaging the inaccessible key end portion within the lock tightly grip the broken key end permitting the same to be pulled from the keyway.
To aid in the retraction of the inaccessible key end after the retractor elements are twisted, a spreader tool of a plier type having thin jaws receivable within the keyway is used to hold tumblers, dust covers, electric switches, and other obstructions, located within the lock out of the lock keyway as the inaccessible broken key end is pulled from the lock. In this manner, the broken inaccessible key end can be pulled from the lock opening without damage to the lock.
In order to improve the gripping of the inaccessible key end portion by the retractor elements, the retractor elements are provided with friction enhancing means in the form of a tooth spirally formed on the elements throughout the elements' blade length whereby the twisting of the elements causes the elements' tooth to firmly grip and partially imbed into the broken key end to increase the frictional connection between the retraction elements and the broken key end permitting the key end to be pulled from the lock.
The retractor elements and spreader can be economically manufactured by conventional fabricating techniques, and the practice of the method of the invention, and the apparatus thereof, are relatively simple and practiceable by users of ordinary mechanical skill.
REFERENCES:
patent: 5938440 (1999-08-01), McSpadden
patent: 5967778 (1999-10-01), Riitano
Watson Robert C.
Young & Basile P.C.
LandOfFree
Broken key extractor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Broken key extractor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Broken key extractor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2449579