Feb. 1, 2008
Should a high level SARGENT Signature master key be lost or stolen, reversing the blocking bars in each lock cylinder and replacing all of the keys is an alternate option to a complete rekeying of the key system.

The term high security has evolved to encompass manipulation resistant lock mechanism(s) and key control, usually patented. There are a number of different types of high security lock mechanisms. Some incorporate multiple shear lines designed to prevent standard picking/manipulation instruments from successfully operating the locking mechanisms. Some of these high security lock mechanisms require specialized servicing tools. Most high security lock mechanisms incorporate a key that has patent protection or is restricted and after-market key blank manufacturers respect this restriction. Some of the more unique keyways and key cuts require special equipment in order to duplicate or originate keys.

The bottom line is each high security lock mechanism has advantages that can be beneficial for specific types of applications. Locksmiths need to have a broad understanding of the “high security” lock mechanisms in order to recommend the lock mechanism(s) that will provide the optimum level of security, balanced with the end-users requirements and desire for convenience.

The Signature® high security lock mechanism incorporates patented key control and manipulation resistance. In addition, the developers considered the existing SARGENT® key systems during the design process. As a result, the SARGENT Signature lock mechanism is backwards compatible into existing SARGENT key systems.

According to SARGENT, “Signature is available using SARGENT key sections (including H, L, R and others), as well as restricted key sections. The Signature feature provides a solution for upgrading the level of security and key control over unauthorized duplication into existing master key systems.”

SARGENT Signature patent number 5,475,998 incorporates the existing pin tumbler lock mechanism with two additional locking mechanisms, one on each side of the keyway. Each locking mechanism incorporates a spring-loaded lock bar that projects into a locking groove in the shell when the lock mechanisms are in the locked position. The additional lock mechanisms are each controlled by three dimple cuts of varying depths of cuts at varying positions along the keyway into the lower portion of the key blade on each side. The positioning of these cuts and the depths of each cut control the locking bars.

In addition, each plug contains two spring-loaded blocking pins that are designed to prevent non-Signature keys from entering the keyway. These pins are located on each side of the keyway in line with the side pins.

The spring-loaded side pins and blocking pins are factory installed into the plug of each lock cylinder. The side pins and blocking pins are press fit into the plug. They remain within the body of the plug even when the plug is removed from the housing. However, the blocking bars and their springs are not retained into the plug. Care must be taken when removing the plug from the shell.

The tip of each Signature key blade is wedge shaped to permit key insertion when sliding past the blocking and side pins. When a Signature key with the proper bitting and side cut dimples is inserted into the lock cylinder, the pin tumblers align at the shear line and the side pins position themselves within the dimple cuts in the key. The side pins have a recess designed to accommodate the offset ridge on the top of the spring loaded locking bars. When properly aligned, each side pin recess is designed to accommodate the offset ridge and the upper portion of the locking bar. As the key starts to rotate, the locking bars slide into the recesses within the body of the plug clearing the shear line.

When the plug rotates back to the “locked” position, the spring-loaded locking bars extend back into the locking grooves in the shell. When the key is removed from the keyway, the pin tumbler top pins obstruct the shear line. The spring loaded side pins return to the “at rest” position, fixing the position of the locking bars between the side pins and the bottom of the locking groove in the shell.

The SARGENT Signature blocking bar ridge is offset for a purpose. This enables each blocking bar to be reversed, creating a new set of side pin battings. Should a high level SARGENT Signature master key be lost or stolen, reversing the blocking bars in each lock cylinder and replacing all of the keys is an alternate option to a complete rekeying of the key system.

Note: Signature keys six pin tumbler bittings can be originated or duplicated using standard key cutting machine.

Because Signature locks and keys can use standard keyways and standard appearing key stock, SARGENT decided to provide an identifier, a quill (feather). All of SARGENT Signature lock cylinders and keys have this quill stamped into the plug faces and the key bows.

To satisfy the end user's requirements, there are two styles of Signature key bows. One bow style contains the SARGENT logo embossed on one side and the Quill logo, specific Signature code pattern and space for one additional line of stamping. The SARGENT code pattern is seven characters. The sample key was stamped with 5J8Z124. The other bow style is blank on the logo side. This enables the end user to have a custom stamping die to personalize their keys. Contact the factory for details.

SARGENT Signature keys are patented, providing controls against unauthorized key duplication. SARGENT Manufacturing controls distribution of Signature key blanks and cylinders. Availability is determined by the keyway, side pin dimple and pattern configuration and geographic area.

End users' needs determine the area of exclusivity for their keyway and the side pin configuration. SARGENT Signature lock mechanisms are available having designated geographic boundaries. The National Boundary incorporates a unique signature pattern that will not be assigned to any other company within the United States .

The next geographic boundary option is Adjacent States, which includes the home state and all adjoining states. For example, a home state of Illinois will have adjoining states of Wisconsin , Iowa , Missouri , and Kentucky .

The third option is for companies that already have an Adjacent State boundary, and have expanded to an additional facility within an adjoining state. Smaller in scope than the National boundary, this incorporates additional states to the Adjacent States and incorporates all Adjoining States. For more information, contact the factory.

SARGENT Signature lock cylinders are serviced the same way as standard pin tumbler lock cylinders. There are two options. The first option is to use a follower to remove the plug from the housing once the cylinder is unlocked. The second method is to remove spring retainer and empty the top, master and bottom pins from the plug and bible.

Note: The blocking pins and side pins are secured into the plug, and are not affected when a plug is removed from the housing.

To provide an “extra hand”, SARGENT developed the Top Loading Tool Kit, part number 436-1. This tool is designed to accommodate mortise and rim cylinders, top loadable removable core cylinders and key-in-knob/lever cylinders. Once the lock cylinder is recombinated , the Top Loading Tool keeps the lock cylinder in position to install the replacement spring retainer.


Step 1. Remove the cam or the tailpiece from the rear of the plug. Key-in-lever/knob lock cylinder may have a “C” clip securing the plug. Be careful when removing as the “C” clip can easily slip out of position.

Step 2. Insert the key into the keyway and rotate the plug approximately 90 degrees.

Step 3. Slide the follower onto the rear of the plug.

Step 4. Slowly slide the plug out of the housing. As the plug begins to slide out, place your finger against the blocking bars to keep them in place.

Step 5. Insert the plug into a loading thimble or similar product, making sure the blocking bars are within the tool. The plug diameter of the SARGENT Signature is .508”.

Step 6. Once the plug has been secured, empty the pin tumblers. Make sure there are no master pins remaining in the shell.

Step 7. Load the correct bottom and master pins.

Step 8. Reassemble the lock cylinder. Test the operation of the lock cylinder.

For servicing Signature lock cylinders, SARGENT offers the Signature Keying Kit, part number 437S. This kit contains top, master, bottom pins, and springs. There are also replacement blocking bars and blocking bar springs. In addition, there are a number of servicing tools including a depth gauge and the field service tool.

For theft and vandal resistant applications, the SARGENT Signature Series lock cylinders are available as UL437 High Security mortise and rim cylinders.

SARGENT Signature lock cylinders offer varying levels of key control, from locksmith wholesaler controlled to factory controlled. Contact the factory for more information.

SARGENT Signature lock cylinders have a one-year warranty.

For more information, contact your authorized SARGENT distributor, SARGENT Manufacturing Company, telephone 800-727-5477 or website