US 4,748,833 AGranted

Button operated combination lock

Assignee501 Nagasawa Manufacturing Co., Ltd.

InventorChiyokichi Nagasawa

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Abstract

This invention relates to a so-called "keyless" type button operated combination lock which can be unlocked by a button operation and locked by a handle operation. A number of buttons exposed on the front side of a case can be set in a combination and a key plate that engages with a bolt lock and keeps it in the locked state is unlocked by setting the buttons, and actuator keys to which they are attached, to a combination but prevents unlocking if the unlocking operation is erroneously carried out. These keys are made in the same shape and size, and the set positions for the memory state and the non-memory state can be interchanged by reversing key positions. These keys are loosely inserted into corresponding slits in the key plate and permit the selection of various operating conditions in conjunction with the key plate slits. When the keys are brought into the "ON" state, they are detachably hooked to the lock plate. The handle, which is operative in the interlocking arrangement with the bolt lock, permits the key plate and the lock plate to simultaneously operate under engagement with each other via a cam pin. Another cam pin engages only with the above-mentioned cam pin and with the lock plate. These cam pins are interchangeable with each other so that the lock of the invention can be fitted to the door as a right-handed type or a left-handed type.

Claims6

Dependent claims

In a button operated combination lock of the type in which a number of button operable actuator keys are disposed with the surfaces thereof accessible in a case frame so as to be capable of being set in a selected combination lock memory state and engaging with, and disengaging from, a key plate, said key plate being engaged with a bolt lock;

the improvement wherein said key plate is slidably supported inside said case frame and has a number of slits bored at predetermined positions therein;
all of said actuator keys being in the form of similar flat plates, each of said said keys being loosely inserted into a corresponding one of said slits and being retractable from said case frame;
a transverse slot formed in each of siad keys intersecting and engaging with said key plate loosely, each of said slots running parallel to and being displaced longitudinallly from the transverse centerline of its associated key, said keys being set in said selected memory state by mounting a preselected set of said keys in said lock with the slots thereof displaced from the transverse centerline in a first direction relative to said key plate with the remainder of said keys being mounted in said lock in inverse relationship to the preselected keys with the slots thereof displaced from said transverse centerline in a direction opposite to said first direction, the slots thereof engaging the key slits when the keys are actuated;
a lock plate slidably mounted in said case frame;
said lock plate and said actuator keys each including means for detachably retaining said actuator keys to said lock plate;
and handle means operative in an interlocking arrangement with said bolt lock and engaging with said key plate and with said lock plate for alternatively opening said lock or resetting said keys in the selected combination memory state by detaching said actuator keys from said lock plate.

3 more elements

Dependencies are inferred from the claim text.