Closure fasteners – Bolts – Sliding
Reexamination Certificate
1999-05-07
2001-09-04
Estremsky, Gary W. (Department: 3627)
Closure fasteners
Bolts
Sliding
C292S039000
Reexamination Certificate
active
06283516
ABSTRACT:
The present invention relates to a lock mechanism.
BACKGROUND OF THE INVENTION
Locks which provide security on one side and easy and quick operation from the other side are used widely, particularly for doors providing an emergency exit from a building.
Commonly such locks use an engineered rack and pinion operating mechanism to operate several strong bolts simultaneously to secure the door. The door is thus secured at various points around its perimeter to provide security and prevent access from one side of the door. When such a door is an emergency exit it is necessary to comply with safety requirements to provide an operating lever inside which will operate by a single simple movement to retract the bolts and unlock the door to allow a safe and quick exit through the door from the building. Typically, a horizontal bar is provided on such doors for the operation of the lock mechanism.
Thus for lock mechanisms used for such doors there are conflicting requirements. One requirement is the security to prevent access from one side whilst the other requirement is a safety requirement to provide for simple and quick operation of the lock mechanism from the inside to allow the door to be unlocked quickly in an emergency.
The lock mechanisms currently available with a direct drive mechanism to the bolts such as a rack and pinion do not provide adequate security since they do not provide resistance to the application of pressure to the ends of the bolts.
GB-A-2289084 disclose a lock mechanism for use on a door hinged in a door frame at a first side. The lock mechanism comprises bolt members moveable between an engaged position in the door frame and a disengaged position. The bolt members are arranged to engage said door frame from at least two of the sides of said door which are not hinged. Latch means are arranged to prevent movement of at least one of the bolt members from the engaged position to the disengaged position. A latch release arrangement is used to disengage the latch means and allow movement of the bolt member. The latch release arrangement and the bolt members are arranged to be operable in response to a single movement of an operating member to allow the latch means to be disengaged and the bolt members to be disengaged from said engaged position. The bolt members are arranged to be directly driven between said engaged and disengaged positions by movement of the operating member.
The lock mechanism of GB-A-2289084 utilises a direct drive mechanism between the operating member, e.g. a handle, and the bolt members providing for positive and visible locking since the position of the operating member will indicate whether the bolt members are properly engaged or not. Such a direct driven bolting arrangement provides for a heavy duty lock mechanism which together with the latching arrangement, which operates when the bolt members are engaged, provides for high security.
Typically, such lock mechanisms include three bolt members—a horizontal bolt member, an upper bolt member and a lower bolt member. A European Standard has made the requirement that application of pressure to the end of the lower bolt member which is able to move the lower bolt member from the engaged position to the disengaged position should not be able to effect movement of the remaining bolt members from the engaged position to the disengaged position.
The present invention therefore seeks to provide a lock mechanism which complies with the European Standard.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a lock mechanism for use on a door hinged at a first side, said lock mechanism comprising a first bolt member and at least one further bolt member, each bolt member being movable between an engaged position extending from the door and a disengaged position, each bolt member being arranged to be directly driveable between said engaged and disengaged positions by movement of a drive member, the first bolt member having a first end for engagement with the drive member and a second end remote from the drive member, the first bolt member being adapted to be reduced in length on application of a pressure towards said first end at said second end.
Advantageously the first bolt member is compressible.
Advantageously the first bolt member comprises a first portion and a second portion coupled together so that said second portion moves towards said first portion on application of a pressure towards said first end at said second end. Preferably said second portion is slidably movable with respect to said first portion. Advantageously said first portion and said second portion are coupled together by a compressible link.
Advantageously the lock mechanism further comprises stop means for preventing movement of said second end with respect to said first end beyond a predetermined displacement. Preferably said stop means comprises a stop member for engagement with a fixed part of the lock mechanism which is fixed with respect to the axis of rotation or oscillation of the drive member, the stop member being mounted on the first bolt member. Preferably the stop member is movable between free and stopped positions with respect to the first bolt member, said free position not enabling engagement of the stop member with said fixed part of the lock mechanism and said stopped position enabling engagement of the stop member with said fixed part of the lock mechanism.
Advantageously the stop member is mounted on one of said first and second portions, the other of said first and second portions including maintaining means for maintaining the stop member in said stopped position on application of a pressure towards said first end at said second end. Preferably said maintaining means comprises a projection slidable with respect to said one of said first and second portions. Preferably the projection is slidable in a slot provided in said one of said first and second portions.
Advantageously the stop member is mounted on said first portion.
Advantageously the stop member is pivotable about a pivot point between said free and said stopped positions.
Advantageously the stop member is rotatable about a mounting point between said free and said stopped positions.
Advantageously the stop member is biased towards said free position.
Advantageously said second portion is biased to move away from said first portion.
According to a second aspect of the present invention there is provided a bolt member for a lock mechanism for use on a door hinged at a first side, the bolt member having a first end for engagement with a drive member of the lock mechanism and a second end remote from the first end, the bolt member being adapted to be reduced in length on application of a pressure towards said first end at said second end. Preferably the bolt member is compressible.
Advantageously the bolt member comprises a first portion and a second portion coupled together so that said second portion moves towards said first portion on application of a pressure towards said first end at said second end. Preferably said second portion is slidably movable with respect to said first portion.
Advantageously said first portion and said second portion are coupled together by a compressible link.
Advantageously the bolt member further comprises a stop member for engagement with a fixed part of the lock mechanism which is fixed with respect to the axis of rotation or oscillation of the drive member and for preventing movement of said second end with respect to said first end beyond a predetermined displacement. Preferably the stop member is moveable between free and stopped positions with respect to the first bolt member, said free position not enabling engagement of the stop member with said fixed part of the lock mechanism and said stopped position enabling engagement of the stop member with said fixed part of the lock mechanism.
Advantageously the stop member is mounted on one of said first and second portions, the other of said first and second portions including maintaining means for maintaining the stop memb
Estremsky Gary W.
Kelly Joseph R.
Surelock McGill Limited
Westman Champlin & Kelly P.A.
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