Metal working – Means to assemble or disassemble – Tumbler lock
Reexamination Certificate
2000-02-09
2001-10-02
Hughes, S. Thomas (Department: 3726)
Metal working
Means to assemble or disassemble
Tumbler lock
C029S432000, C083S518000, C070S372000, C070S431000
Reexamination Certificate
active
06295725
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to apparatus used by locksmiths for the assembly of interchangeable core locks and more particularly, to an improved such device and process that simplifies and shortens the duration of such an operation.
BACKGROUND OF THE INVENTION
In cylinder locks of conventional design, a cylindrical key-receiving plug having a first series of radially disposed channels is rotatably mounted within a cylindrical bore in a housing having a second matching series of channels known as “pin chambers”. The pin chambers are in coaxial alignment with the first series of channels and open upon the bore. The opposite extremities of the pin chambers, furthest from the bore, are closed. Each pin chamber is adapted to confine a coil spring in abutment with the closed extremity, and a bottom pin that is urged toward the key-receiving plug by the spring. In some cases, one or more top pins, control pins or master pins may be positioned between the spring and the bottom pin within the pin chamber. The combination of pin lengths determines a code for opening the lock.
In certain types of cylinder locks, generally referred to as interchangeable core locks, the portion of the housing that contains the plug and pin chambers is part of an assembly known as a “core” that is slideably removable from the lock when released by a control key. The controlled removeability of the core is desired by institutions and others where a high turnover of employees necessitates a periodic change of locks to maintain security. Cores of several different codes may be kept by the institution, all keyed to a single control key but requiring different operating keys to open the individual locks. Changing of the locks requires a total recoding of the core to accept another key. In such a case, assembly of a new and different core is required.
The core further contains the cylindrical bore that houses the key receiving plug and the wall of the bore has a series of apertures axially aligned with the first series of channels and diametrically opposed thereto. The extremities of the pin chambers furthest from the bore are closed by means of friction fit discs or “caps” as they are commonly called. Assembly of the core requires insertion, in the proper order of bottom pins, master pins, control pins, top pins, springs and finally caps into the pin chambers. As all of these parts are very small, assembly can be a long and tedious operation. Insertion or application of the caps can be a particularly frustrating part of the operation. The caps are very small and, in addition to the obvious problem of inserting them into the similarly small pin chambers, they must be squarely and precisely aligned in order to achieve the appropriate friction fit. They must then somehow be driven into the pin chamber by striking with a hammer, mallet or the like to achieve the friction fit. Misalignment entails removal of the cap and reinsertion with the possibility of further misalignments before proper cap installation is achieved. This operation must be repeated for each pin chamber of which there are conventionally either six or seven.
Thus, a method and apparatus that would permit simplified, convenient and aligned installation of a plurality of friction fit caps into the pin chambers of a core all at one time would be highly valued by locksmiths.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a simplified, convenient and accurate method for achieving multiple cap insertion that obviates the need for cap handling and assures proper alignment and insertion of all of the caps into all of the pin chambers of a single core on the first attempt.
It is another object of the present invention to provide an apparatus that makes the operation of installing the multiple caps into the pin chambers simple, convenient and accurate.
SUMMARY OF THE INVENTION
According to the present invention, there are provided a method and an apparatus for the installation of interchangeable core lock caps that replace the prior art individual cap installation techniques with one that, with a single mechanical stroke, punches the caps for a plurality of pin chambers from a strip of appropriate metal and frictionally fits them into the plurality of pin chambers. The method and apparatus of the present invention reduce the possibility of misalignment of the caps with the pin chambers to virtual zero and eliminate entirely the need to handle the small caps.
These advantages are achieved by: 1) placing a lock core having pin chambers loaded with the appropriate pins into a fixture, inserting springs into the core, the fixture has a slanted die with apertures registered with the pin chambers; 2) placing a strip of metal in a fixed position over the die; and 3) through a mechanical plunger linked to a plurality of punches, driving the plurality of punches sequentially through the metal strip to form punched metal caps. The punched metal caps are then driven into frictional engagement with the registered pin chambers of the lock core through continued action of the plunger.
REFERENCES:
patent: Re. 35518 (1997-05-01), Sussina
patent: 3176488 (1965-04-01), Jacobi
patent: 4663839 (1987-05-01), Foshee
patent: 6044530 (2000-04-01), Room et al.
King Ricky Lee
Robinson Robert F.
A-1 Security Manufacturing Corp.
Hong John C.
Hughes S. Thomas
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