Patent Search

Thanks for the reply, Billy. Of course it helps if one knows the right tools for efficiently searching the USPTO database <blush>, Lots of single-dial padlock patents in the 70-21 class. I am amazed at how much these types of lock differ internally. The Soref & Foote design for Master Lock (using a spring-loaded plunger to secure the shackle and which can be depressed by a simple cylinder/lever plate mechanism for key operation) appears to use an economy of parts compared to other designs. Elegance in simplicity. Clearly the plunger spring must be designed to hold up over the life of the lock and resist rapping. (These patents never talk about shackle hardness and resistance to bolt cutters!)

A few of the designs place the keyway in the center of the dial at the front of the lock. That's certainly convenient but it does complicate the design (as evidenced in the drawings) compared to having the keyway in the back.

Some of the workding in these patents anticipated a general market (forgotten combinations but not lost keys) for this type of padlock. In sddition to the venerable #1525 padlock (AFAIK never intended for sale to the general public), Master Lock offers its #2076DAST Sphero dual combination/key padlock as a consumer product and it comes with two keys. Nice. I've discovered this lock can be hard to locate in stores, though, compared to the #2075DAST combo-only lock.

Now, just because a patent exists doesn't mean the padlock was manufactured and perhaps turned a profit. That will be harder to determine. Sincerely,

John Wood (Code 5550) e-mail: snipped-for-privacy@itd.nrl.navy.mil Naval Research Laboratory

Thanks for the reply, Billy. Of course it helps if one knows the right tools for efficiently searching the USPTO database <blush>, Lots of single-dial padlock patents in the 70-21 class. I am amazed at how much these types of lock differ internally. The Soref & Foote design for Master Lock (using a spring-loaded plunger to secure the shackle and which can be depressed by a simple cylinder/lever plate mechanism for key operation) appears to use an economy of parts compared to other designs. Elegance in simplicity. Clearly the plunger spring must be designed to hold up over the life of the lock and resist rapping. (These patents never talk about shackle hardness and resistance to bolt cutters!)

A few of the designs place the keyway in the center of the dial at the front of the lock. That's certainly convenient but it does complicate the design (as evidenced in the drawings) compared to having the keyway in the back.

Some of the wording in these patents anticipated a general market (forgotten combinations but not lost keys) for this type of padlock. In addition to the venerable #1525 padlock (AFAIK never intended for sale to the general public), Master Lock offers its #2076DAST Sphero dual combination/key padlock as a consumer product and it comes with two keys. Nice. I've discovered this lock can be hard to locate in stores, though, compared to the #2075DAST combo-only lock.

Now, just because a patent exists doesn't mean the padlock was manufactured and perhaps turned a profit. That will be harder to determine. Sincerely,

John Wood (Code 5550) e-mail: snipped-for-privacy@itd.nrl.navy.mil Naval Research Laboratory