HK1069860A - Security lock supporting master keying - Google Patents

Description

Safety lock supporting main locking

Technical Field

The present invention relates to an improved lock and more particularly to a lock which can support a primary lock with a set of secondary keys.

Background

It is desirable to have a lock that can be rekeyed without having to change the lock, and that has the additional feature of having a master key and multiple secondary keys, and that does not require a new locking mechanism when one of the keys needs to be changed.

Us patent 4741188 discloses a pin tumbler lock which enables a key to be changed without changing the lock. The lock may also have a master key and a plurality of secondary keys, and one disadvantage of the pin tumbler lock is that it is expensive to manufacture due to the skilled machining and the complex assembly.

Us patent 4898011 discloses a lock for replacing a pin tumbler lock, which does not require replacement of the lock. Instead of aligning the key with the pin to rotate the cylinder, the key is aligned with the pin with holes to allow the plurality of elongated members to pass through to activate the bolt. Each key has an associated nub (bisuit) which holds one set of pins in place, and a matching key aligns the holes in the second set of pins with the holes in the first set of pins, with master keying being achieved by providing more than one hole on each pin.

WO98/40589 discloses a programmable cylinder lock having one or more master keys and which is rekeyable. The cost of manufacturing such locks and the capital required for the equipment are high.

Disclosure of Invention

It is an object of the present invention to provide a cheap and safe lock which can be rekeyed without replacing the lock and which allows for primary locking at one or more levels.

To this end, the present invention provides a lock of the type in which latch means can be activated if an elongate element is able to pass through an associated slot in a latch element, one of the elongate element or latch element being positioned by a locator and the other being positioned by a key shaped to correspond to the shape of the locator so as to align the slot of the latch element with the end of the elongate element, the improvement being that at least one latch element is provided with a wider slot to effect master keying.

The present invention is an improvement over the lock construction of us patent 4898011 which achieves a master lock at more than one level. The contents of patent 4898011 are incorporated herein by reference. When the bolt elements are positioned vertically, the wider slots extend in a vertical direction and are taller than the slots in the other bolt elements. In the context of the present invention, wider in relation to the slot in the bolt element arrangement means taller if the bolt element is positioned vertically. Throughout this specification, a slot in the bolt element refers to a hole through the body of the bolt element or a channel-like groove that can receive and guide the elongate trigger element.

In an embodiment of the invention having two sets of latch elements such that when the slots in each set of elements are aligned, the trigger element is passed, one set of latch elements being positioned by a locator and the other set being positioned by a key, the shape of the key corresponding to the shape of the locator so as to align the slots of the corresponding elements in each set of elements, the improvement wherein at least one latch element in a set of elements is provided with a wider slot to achieve master keying. When one set of bolt elements comprises an element having 5 position wide slots, there are 5 corresponding slots in the mating element of the second set of elements which allow passage of the trigger element, which means that there are 5 coding positions allowing 5 access levels to be controlled, the master key can enter the lock at all 5 levels, the second highest level does not allow access to the master level but allows access to the 4 lowest levels. Continuing with this hierarchy, all key holders are able to access the lowest level of locks, but the lowest level key holder is not able to access the higher level locks. The number of levels may be determined by the width of the slot and the number of bolt elements having wider slots, and the master key will typically be positioned at a location corresponding to the bottom or top of the wider slots so that it can enter the other levels.

Drawings

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

fig. 1 is a schematic view of the key and retainer configuration of patent 4898011.

Fig. 2A, 2B, 2C schematically illustrate the alignment of the slots and the use of wider slots to achieve the primary lock.

Detailed Description

As shown in fig. 1, a key 57 is inserted into the keyway 48, during which a set of latch or pin elements 50 are pushed downwardly with their lower ends 52 engaging a profiled edge 58 of the key 57, each latch element 50 including a slot 54, the slot 54 serving as a passage for a trigger element as described in patent 4898011, a nub or codable retainer 55 being disposed in the keyway 49, the nub or retainer 55 having a profiled edge 56 corresponding to the edge 58 of the key 57. When the key 57 and the retainer 55 are inserted into the respective keyholes 48 and 49, respectively, the slot 54 in each of the latch elements 50 in the keyholes 48 is aligned with the slot 54 in the latch element in the keyhole 49.

This is seen in fig. 2A, where the latch element 62 in the locator keyhole 49 has a slot or channel 64 that is identical to the channel 54 in the latch element 50 of the keyhole 48, and fig. 2B shows a wide or high slot 65 in the latch element 62 for the locator, with the bottom 66 of the slot 65 corresponding to the lowest position of the slot 54 in the corresponding element 50 for the key. There may be four positions or codes for the trigger arm 60 to pass through the slots 54 and 65. These positions are achieved by increasing the height of the key profile corresponding to the bolt elements 50 by an increment corresponding to from a portion of the thickness of the trigger 60 to the entire thickness of the trigger 60. If a portion of the thickness is increased, the increments are smaller, which allows more incremental positions to be accommodated in a given size of bolt element 50. The master key is the key with the highest height for the key profile corresponding to element 50. The keys and locators have corresponding profiles, meaning that the lowest level locator will have the lowest profile height for the bolt elements and all higher keys, including the master key, will allow the trigger to pass through the slot, but for locks with master locators, each lower level key cannot increase the key bolt element height enough to allow the trigger to pass through the slot in the pin in the key row.

The opposite configuration is seen in fig. 2C, where the 4 coding positions are obtained by gradually reducing the height of the key profile for the bolt elements, the top 67 of the slot 65 corresponding to the uppermost position of the slot 54 in the corresponding element 50 of the key. The master key has the lowest profile for that element, meaning that a lower level key will not lower the bolt element enough to pass the trigger 60 through the locator slot 65.

The wide (tall) slot 65 need not be in the retainer row 49 of bolt elements 62, and it is equally effective to have a wider slot in one element 50 in the key row 48. More than one wide slot pin element (50, 62) may be used in the set.

The keys and locators may be color coded to manage the location of the keys, which allows one lock mechanism to be used for a greater number of key combinations with 5 entry levels. The set of keys and detents can be replaced with a new set of keys and detents or the lowest detent can be replaced and this coding arrangement can be used in the lock mechanism disclosed in us 4898011 where the lock is not activated by turning the key or in the mechanism described in co-pending application PR8387 filed on the same day as this application by the present applicant.

It will be apparent to those skilled in the art of making locks that the invention is applicable to any lock in which the slot in the bolt is aligned with the end of the trigger element which passes through the slot to trigger the lock.

Claims (4)

1. In a lock in which a latch means can be activated if an elongate element is able to pass through an associated slot in a latch element, one of the elongate element or the latch element being positioned by a locator and the other being positioned by a key shaped to correspond to the shape of the locator so as to align the slot of the latch element with the end of the elongate element, the improvement being in that at least one latch element is provided with a wider slot to effect master keying.

2. A lock according to claim 1 wherein there are two sets of bolt elements such that when the slots in each set of elements are aligned the trigger element can pass through, wherein one set of bolt elements is positioned by the locator and the other set is positioned by a key, the shape of the key corresponding to the shape of the locator so as to align the slots of the corresponding elements in each set of elements, the improvement being that in one set at least one bolt element is provided with a wider slot so as to achieve master keying.

3. A lock according to claim 1 or 2, wherein the slot width corresponds to the thickness of the elongate trigger element, and a wider slot is the slot width plus one or more increments ranging from a portion of the trigger element thickness to the entire trigger element thickness.

4. A lock according to claim 3, wherein the width of the wide slot may be up to 5 increments wider than the width of the elongate trigger element.