Rekeying tool for a lock

A rekeying tool for a lock having a lock body, cylinder, upper and lower tumbler pins and upper springs, includes a cylindrically elongated follower having opposing ends. At least one of the ends is hollow and has a V-shaped or U-shaped groove. A cylindrically elongated solid piston having a corresponding V-shaped or U-shaped groove at an end is resiliently positioned in the hollow end of the follower. The solid piston includes a cut-through channel and a pin. The pin extends a cross-section of the hollow end of the follower and passing though the cut-through channel to guide reciprocating travel of the piston from an inwardmost position to an outwardmost extension. The V-shaped or U-shaped groove of the solid piston is substantially aligned with the corresponding V-shaped or U-shaped groove of the hollow end of the follower when the piston is at the outwardmost extension.

FIELD OF THE INVENTION

This present invention relates generally to a lock and, more particularly, to a lock rekeying tool for effectively inspecting, maintaining and rekeying the pins and springs within a lock assembly having a lock cylinder and lock body.

BACKGROUND OF THE INVENTION

This invention relates to a rekeying tool for a lock assembly, shown inFIG. 1, for example, having a lock body with a locking cylinder rotatably alignable therein. The locking cylinder includes a plurality of radially extending bores (typically five to six) alignable with mating bores in the lock body. Each bore in the lock body includes an upper pin and corresponding spring biasing the upper pin toward an axially aligned lower tumbler pin in the corresponding mating bore of the locking cylinder. Further describing the bores in the locking cylinder body, each is perpendicular to and aligned in a row along the cylinder's axis.

Locks of this type tend to wear, particularly on the contact surfaces of the pins. For example, the pins in the locking cylinder are constantly rubbed by the key to adjust the position of the pins so that the cylinder may be turned within the lock body. The rubbing causes wear and eventually lock failure. This problem is often corrected by replacing the tumbler pins within the rotatable cylinder. Still further, select tumbler pins are replaced with pins of different length when rekeying the lock.

A problem is presented when rekeying or maintaining a lock, in that, when the lock cylinder is removed from the lock body, the upper pins, which remain disposed within bores in the lock body, are not positively maintained in position, and, since the same are resiliently urged into the space formally occupied by the cylinder, the upper pins and springs become dislodged from the bores in which they were originally positioned; therefore, necessitating the repositioning of the same before the lock is reassembled.

Since the upper pins positioned in the lock body do not wear, as do the lower tumbler pins, upper pins are not typically replaced with new pins. Therefore, there is often no reason for their removal when replacing the lower tumbler pins. However, the springs may sometimes need maintained and replaced if the spring force is damaged or worn with use. Still further, the pins in both the lock body and lock cylinder are relatively small in size, and the same are not readily repositioned without considerable effort on the part of the locksmith. As a result, the process of inspecting, maintaining and/or rekeying a lock is intricate, requires careful skill, and often time consuming.

While these devices may accomplish their particular objective, the aforementioned patents do not disclose a single-unit, lock rekeying tool made and used to more effectively inspect, maintain and retool the pins within locking cylinders having a tail extension. Moreover, various lock assemblies have differently designed lock bodies and cylinders. Some lock cylinders have various tail extensions. Therefore, multiple tools and steps are required to prevent the tumbler pins and springs from being dislodged while removing these types of locking cylinders. When rekeying or servicing such locks, the tail extension must be removed or two tools are needed to slide the locking cylinder from the lock body: a hollow tool and a solid tool. The locksmith must work with both tools interchangeably to gain access to the small pins and springs of the lock assembly.

More specifically, the first tool (i.e., having a hollow cross-section) is used to encase the tail extension. Otherwise, on account of the changing configuration and outside diameter of the locking cylinder (particularly at the transition between the tail extension and actual cylinder housing) pins and springs could easily dislodge as the cylinder is being guided from the locking cylinder. To make repairs and/or rekey the lock, a second tool (i.e., having a solid cross-section) is slid behind the hollow tool. The second tool is needed to better manipulate, repair and/or replace the several paired spring and pin combinations in the mating bores of the lock body. Finally, to re-assemble the locking cylinder in the lock body, the task is reversed (i.e., changing from the second tool back to the first tool) to slide the locking cylinder back in place in the assembly.

SUMMARY OF THE INVENTION

The purpose of the instant invention is to eliminate the need for two separate tools. The instant invention uniquely combines both the hollow and solid tools into a single tool, thereby allowing the user to eliminate steps and need to switch between the different tools.

Accordingly, the rekeying tool in this invention includes a cylindrically elongated follower having opposing ends. At least one of the ends is hollow and has a V-shaped or U-shaped groove. A cylindrically elongated solid piston having a corresponding V-shaped or U-shaped groove at an end is resiliently positioned in the hollow end of the follower. The solid piston includes a cut-through channel and a pin. The pin extends a cross-section of the hollow end of the follower and passes through the cut-through channel to guide reciprocating travel of the piston from an inwardmost position to an outwardmost extension. The V-shaped or U-shaped groove of the solid piston is substantially aligned with the corresponding V-shaped or U-shaped groove of the hollow end of the follower when the piston is at the outwardmost extension.

Thus, it will be seen that, with the instant rekeying tool, the upper pins and spring of the lock body can be checked, and lower tumbler pins in the lock cylinder can be replaced without repeatedly switching between the hollow and solid tools. As a result, by using the instant rekeying tool, steps are eliminated in the rekeying and/or servicing process, thereby saving time, avoiding mistakes, and preventing aggravation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference toFIGS. 2 through 5, a rekeying tool40, in this case, includes an elongated hollow follower42which has substantially the same outside diameter and cylindrical shape as a locking cylinder or plug12of a lock assembly10. Two pistons44A,44B are spring-biased within an inside diameter of the hollow follower42. Each solid piston or inside follower44A,44B is positioned at and biased outward, at opposite ends of the hollow follower42. The outermost end of each solid follower44A,44B has a V-shaped or U-shaped groove50A,50B extending longitudinally inward. More specifically, the wide opening of the groove50A,50B is at the very outer end of the solid follower44A,44B, respectively, and the groove progressively narrows inwardly. Each groove50A,50B is used as a vertical pin guide when checking and/or replacing the upper pins18and corresponding springs20in the lock body14. A matching V-shaped or U-shaped groove60A,60B is formed at each opposing end of the hollow follower42of the rekeying tool40to shadow or conform to the corresponding V-shaped or U-shaped groove50A,50B of the corresponding solid followers44A,44B, when the solid followers are at its farthest (i.e., outwardmost) extended position, which is discussed further infra with reference to the in-and-out movement of each solid follower.

Each solid follower44A,44B includes a guide channel49A,49B cut along its longitudinal axis. A set screw or pin48A,48B, passes through one of the corresponding cut-out channels49A,49B to properly orient and reciprocally guide its respective solid follower44A,44B, inwardly and outwardly along the elongated axis of the hollow follower42. The ends of the corresponding cut-through channel49A,49B act as stops along a traveling path (for an inwardmost position and an outwardmost extension of travel for each solid follower44A,44B). Further, each solid follower44A,44B is biased by one or more springs46pushing the solid followers outward, toward its corresponding outwardmost extension within the hollow follower42of the rekeying tool40. When at its outwardmost extension, each V-shaped or U-shaped groove50A,50B of the corresponding solid follower44A,44B, respectively, is aligned with the corresponding V-shaped or U-shaped groove60A,60B of the hollow follower42. Therefore, each set screw or pin48A,48B holds its corresponding solid follower44A,44B in position and acts as a limiting in-and-out guide.

As a result, the in-and-out reciprocating travel of solid followers44A,44B allows the rekeying tool40to adjustably fit different models of locking cylinder plugs12. More specifically, in operation, the bias of each solid follower44A,44B allows it to collapse inside the hollow follower42of the rekeying tool40, thereby allowing any tail extension26of the locking cylinder12to pass into the hollow follower42.

In use, therefore, to avoid having to remove the tail extension26from the cylinder12, the tail extension26of the locking cylinder12(which may have different lengths and shapes) is pushed against the solid follower44A,44B and into the hollow follower42of the rekeying tool40as best seen inFIG. 5. The locksmith then guides the rekeying tool40into the lock body14to push out and replace the locking cylinder12therewith.

Once the locking cylinder12is removed, the locksmith can rekey the lock by replacing the selected lower tumbler pins16in the locking cylinder12. The locksmith can also service the lock body14by retracting the rekeying tool40to check and replace (if necessary) the springs20and upper pins18by using the corresponding V or U-shaped groove50A or50B of the respective solid follower44A,44B (now at its outwardmost extension) and the corresponding, aligned V or U-shaped groove60A,60B of the hollow follower42(which, in combination, form a pin guide as discussed supra).

After checking and replacing the pins18and springs20as needed, the locking cylinder12is reassembled with the lock body14by reversing the steps (i.e., axially aligning and inserting the tail extension26of the locking cylinder12with the hollow follower42and then slidably guiding the locking cylinder12back in place in the lock body14). As the locking cylinder12is guided into the lock body14, the rekeying tool40is simultaneously pulled out. Like the disassembly step of the process, the outer surface of the hollow follower42keeps the upper pins18and springs20from being dislodged as the locking cylinder12replaces the rekeying tool's position in this re-assembly step.

The newly developed rekeying tool described above should be understood to extend to any and all modifications, variations, adaptations, deviations and embodiments that would occur to one skilled in this technology, once having possessed the teachings of the present invention. Therefore, the present invention should be limited only by the claims.