Novice
#1NBBSIR 80-1989 appears to be a genuine report suggesting some interesting enhancements to handcuff mechanisms. The report claims that prototypes were produced and tested. Has anybody come across these modified cuffs, or know of the study/report?
Maybe someone here might even be tempted to manufacture something along the lines suggested? Could be a reasonable market among enthusiasts . . .
Sorry if this is one of those topics that keep coming up!
Main content -
NBSIR 80-1989
A STUDY OF HANDCUFF IMPROVEMENTS
James E. Harris
Product Performance Engineering Division
Center for Consumer Product Technology
National Engineering Laboratory
National Bureau of Standards
Prepared by
Law Enforcement Standards Laboratory
Center for Consumer Product Technology
National Bureau of Standards
Washington, D.C. 20234
March 1980
Issued April 1980
Prepared for
National Institute of Justice
U.S. Department of Justice
Washington, D.C. 20531
[ *** Preamble ignored *** ]
DESCRIPTION OF OPERATION, MODIFIED HANDCUFFS
The modified (improved lock) handcuffs that were developed during this study operate on the same principle as the standard handcuff with the following additions. The improved handcuff has means to automatically lock the bolt in the active position. Locking of the bolt in the active position is called triple locking. Refer to figure 3 to follow the operation of the triple locking feature. When the double lock bolt is moved fully to the active position, the pawl spring now forces the corner of the bolt against the housing wall, so that movement to the inactive position is prevented by a ledge inside the handcuff housing. Once the double lock bolt is active, it can only be moved to the inactive position by unseating it from the ledge so that the corner of the bolt will clear the corner of the ledge. It can be seen that the bolt must be unseated prior to and during lateral motion when the bolt moves to the inactive position. As before the lateral motion of the bolt is caused by the tang of the key or the picking tool.
Two methods have been developed to unseat the bolt under normal operation. One method of unseating the bolt is by the use of a second key which is inserted through a new secondary keyhole located on the opposite side of the handcuff from the standard or primary keyhole as shown in figure 4. Rotation of the second key causes the tang to move the bolt downward and away (unseating) from the ledge. The standard or primary key is inserted through its keyhole and this second key is rotated so that the tang of the key moves the bolt to the inactive position. Both keys or two picking tools must be operated simultaneously to unlock the handcuff and since they are from the opposite sides of the ,handcuff the skill required is high. This results in a difficult feat for a handcuffed person to perform, which improves the security features of the lock. A second method of unseating the bolt is to use a hollow swivel with a concentric protruding pin that serves as a push rod when the chain link within the eye of the swivel is grasped and pressed upon the tip of the protruding pin as shown in figure 5. The pin transmits a force that presses the bolt downward and away (unseating) from the ledge. The key must then be inserted and rotated so that the tang of the key moves the double lock bolt to the inactive position. The action of grasping and pressing of the chain link against the pin to unseat the bolt must be done simultaneously with the turning of the key. These operations are difficult to perform by a handcuffed person because they require a high degree of manual dexterity. The security of the handcuff lock is thereby improved.
An additional improvement for the locking of the handcuff was developed that automatically double locks (and consequently could triple lock) the handcuff when applied about a wrist or other object. Refer to figures 6 and 7. I-Then the handcuff is applied and closed about a wrist, the pressure of the double/triple lock lever against the wrist will cause counterclockwise rotation of the lever. This rotation will move the other end of the lever to the left where it will engage the pusher, which has been lengthened to protrude from the body of the handcuff, and press upon it thereby moving the double lock bolt to the active position. The handcuff will then be multiple locked. This action is automatic when the handcuff is properly applies. By proper design of the geometry of the lever and its pivot, it will be impossible to apply excessive squeezing pressure to the wrist because the lever will activate the double lock and prevent further closure of the handcuff. Officers will not need to use the key to activate the double lock, a maneuver that is difficult to do in the dark or with a hostile individual. Also, officers will not forget to activate the double lock since this improvement causes automatic multiple locking. If combined with the previous improvement, triple locking is effected automatically when the double lock is activated.
The improvement of automatically triple locking makes it very unlikely that any directed shock would be able to unseat and unlock the bolt. In order to accomplish this, one shock would he required to unseat the bolt and while the bolt was unseated against the pawl spring force, a second shock at a right angle to the first would be required to move the bolt to the inactive position. it is very unlikely that anyone would be skillful enough to apply such shocks in the proper direction, intensity and sequence even if they knew how these shocks were required. Finally, it is doubtful if a single shock could replace the two right-angled components because of the internal friction of the sliding bolt against the ledge.
Maybe someone here might even be tempted to manufacture something along the lines suggested? Could be a reasonable market among enthusiasts . . .
Sorry if this is one of those topics that keep coming up!
Main content -
NBSIR 80-1989
A STUDY OF HANDCUFF IMPROVEMENTS
James E. Harris
Product Performance Engineering Division
Center for Consumer Product Technology
National Engineering Laboratory
National Bureau of Standards
Prepared by
Law Enforcement Standards Laboratory
Center for Consumer Product Technology
National Bureau of Standards
Washington, D.C. 20234
March 1980
Issued April 1980
Prepared for
National Institute of Justice
U.S. Department of Justice
Washington, D.C. 20531
[ *** Preamble ignored *** ]
DESCRIPTION OF OPERATION, MODIFIED HANDCUFFS
The modified (improved lock) handcuffs that were developed during this study operate on the same principle as the standard handcuff with the following additions. The improved handcuff has means to automatically lock the bolt in the active position. Locking of the bolt in the active position is called triple locking. Refer to figure 3 to follow the operation of the triple locking feature. When the double lock bolt is moved fully to the active position, the pawl spring now forces the corner of the bolt against the housing wall, so that movement to the inactive position is prevented by a ledge inside the handcuff housing. Once the double lock bolt is active, it can only be moved to the inactive position by unseating it from the ledge so that the corner of the bolt will clear the corner of the ledge. It can be seen that the bolt must be unseated prior to and during lateral motion when the bolt moves to the inactive position. As before the lateral motion of the bolt is caused by the tang of the key or the picking tool.
Two methods have been developed to unseat the bolt under normal operation. One method of unseating the bolt is by the use of a second key which is inserted through a new secondary keyhole located on the opposite side of the handcuff from the standard or primary keyhole as shown in figure 4. Rotation of the second key causes the tang to move the bolt downward and away (unseating) from the ledge. The standard or primary key is inserted through its keyhole and this second key is rotated so that the tang of the key moves the bolt to the inactive position. Both keys or two picking tools must be operated simultaneously to unlock the handcuff and since they are from the opposite sides of the ,handcuff the skill required is high. This results in a difficult feat for a handcuffed person to perform, which improves the security features of the lock. A second method of unseating the bolt is to use a hollow swivel with a concentric protruding pin that serves as a push rod when the chain link within the eye of the swivel is grasped and pressed upon the tip of the protruding pin as shown in figure 5. The pin transmits a force that presses the bolt downward and away (unseating) from the ledge. The key must then be inserted and rotated so that the tang of the key moves the double lock bolt to the inactive position. The action of grasping and pressing of the chain link against the pin to unseat the bolt must be done simultaneously with the turning of the key. These operations are difficult to perform by a handcuffed person because they require a high degree of manual dexterity. The security of the handcuff lock is thereby improved.
An additional improvement for the locking of the handcuff was developed that automatically double locks (and consequently could triple lock) the handcuff when applied about a wrist or other object. Refer to figures 6 and 7. I-Then the handcuff is applied and closed about a wrist, the pressure of the double/triple lock lever against the wrist will cause counterclockwise rotation of the lever. This rotation will move the other end of the lever to the left where it will engage the pusher, which has been lengthened to protrude from the body of the handcuff, and press upon it thereby moving the double lock bolt to the active position. The handcuff will then be multiple locked. This action is automatic when the handcuff is properly applies. By proper design of the geometry of the lever and its pivot, it will be impossible to apply excessive squeezing pressure to the wrist because the lever will activate the double lock and prevent further closure of the handcuff. Officers will not need to use the key to activate the double lock, a maneuver that is difficult to do in the dark or with a hostile individual. Also, officers will not forget to activate the double lock since this improvement causes automatic multiple locking. If combined with the previous improvement, triple locking is effected automatically when the double lock is activated.
The improvement of automatically triple locking makes it very unlikely that any directed shock would be able to unseat and unlock the bolt. In order to accomplish this, one shock would he required to unseat the bolt and while the bolt was unseated against the pawl spring force, a second shock at a right angle to the first would be required to move the bolt to the inactive position. it is very unlikely that anyone would be skillful enough to apply such shocks in the proper direction, intensity and sequence even if they knew how these shocks were required. Finally, it is doubtful if a single shock could replace the two right-angled components because of the internal friction of the sliding bolt against the ledge.