Mortise lock

Details Mortise lock Mortise lock

2000-05-22

2002-05-28

Arthur, Gertrude (Department: 3661)

Locks

Special application

For closures

C070S010000, C070S011000, C070S106000, C292S169140, C292S169170, C292S335000

Reexamination Certificate

active

06393878

ABSTRACT:

BACKGROUND
This invention relates generally to mortise locks, and more particularly to a mortise lock for use where a high level of security is desired.
A mortise lock is designed to fit into a mortised recess formed in the edge of a door which is opposite to the edge of the door that is hinged to the door frame. The mortise lock generally includes a rectangular housing, or case, which encloses the lock components. The principal lock component is a beveled latch bolt which projects beyond the edge of the door and into an opening in the door frame to latch the door in a closed position. The latch bolt is moveable to a retracted position inside the case to permit opening of the door by operation of a latch operator, such as a door knob or lever handle.
Mortise locks are typically configured so that the latch operators mounted on the inside and outside surfaces of the door can operate independently. The outside latch operator can either be rotated to retract the latch bolt, or locked against rotation to prevent retraction of the latch bolt. Preferably, the inside latch operator can always be rotated to retract the latch bolt. The locking of the outside latch operator is usually controlled by a manual actuator, such as, for example, push buttons or a pivoted toggle, which is exposed at the edge of the mortise lock near the latch. The manual actuator has an associated link within the mortise lock case which, in one position of the manual actuator, engages a moveable portion of the outside latch operator inside the lock case so as to prevent rotation of the latch operator. In a second position, the link disengages from the moveable portion thus permitting rotation of the outside latch operator. The inside latch operator is usually unaffected by the manipulation of the manual actuator and remains rotatable at all times.
Adjustments must be made to the mortise lock depending on whether the lock is mounted in a left-hand or right-hand door. A mortise lock mounted in a left-hand door must be rotated 180° about a vertical axis for mounting in a right-hand door. Consequently, the latch bolt must also be rotated 180° about a horizontal axis so that the beveled face of the latch faces the door-closing direction. In addition, the inside and outside latch operators of the left-hand door mounted lock become the outside and inside latch operators, respectively, of the right-hand door mounted lock. Therefore, a change must be made if the latch operator controlled by the locking mechanism happens to be the inside latch operator when the lock is installed.
The necessary adjustments to the mortise lock can be accomplished without opening the case. Typically, the latch bolt can be pulled partially out of the housing, usually against the force of a spring, rotated 180° and then allowed to be pulled back into the housing by the spring. However, this arrangement can lead to tampering after the lock is installed since the latch bolt can be reversed even when the mortise lock is in the door, which would prevent the door from closing. Moreover, conventional mechanisms for reversing the operation of the locking mechanism are complicated and difficult to manipulate.
Further, some mortise lock applications require a high degree of security, including government buildings, banks, prisons and storage facilities, as well as other applications where a higher degree of security may be desired. The latter may include institutional settings such as schools, and in particular classrooms. A typical classroom function mortise lock includes a latch bolt operable by an inside or outside lever handle. The outside lever handle may be locked against rotation by a key-operated cylinder in the outside of the door. A significant problem with this arrangement is that the latch can only be locked from the outside. As a result, if a teacher inside the room wants to lock the door, she must open the door to operate the outside cylinder.
For the foregoing reasons, there is a need for a mortise lock for use in applications where a high degree of security is preferred. The new, high security mortise lock should be lockable from the inside of the door. The new lock should also conveniently handle high traffic use. Ideally, the high security mortise lock is reversible and the latch assembly for use in the lock includes a latch bolt that cannot be reversed after the lock is installed in a door. Reversal of the latch bolt for use with a door of the opposite hand should be easily accomplished in the field. Any corresponding changes in the locking mechanism during reversal to effect locking of the outside latch operator should also be uncomplicated. The new latch assembly and locking mechanism should be straightforward to manufacture and use.
SUMMARY
Therefore, it is an object of the present invention to provide a high security mortise lock, particularly for use in institutional applications such as schools.
Another object of the present invention is to provide a high security mortise lock which can be locked from the inside of the door.
Still another object of the present invention is to provide a high security reversible mortise lock wherein the latch assembly cannot be reversed when the lock is installed on the door.
A further object of the present invention is to provide a new latch assembly and locking mechanism for a high security mortise lock which are simple to reverse in the field prior to installation in the door.
According to the present invention, a mortise lock includes a housing for a latch bolt and a deadbolt which are mounted in the housing for movement between a retracted position where the latch bolt and deadbolt are inside the housing and an extended position where a portion of the latch bolt and deadbolt extend from the housing. First means are provided for moving the deadbolt between the retracted and extended positions. Second means, including a moveable member in the housing, are provided for retracting both the latch bolt and the deadbolt. A blocking element is mounted in the housing for movement between a first position and a position where the blocking element prevents movement of the moveable member. A locking lever operatively connects the deadbolt and the blocking element so that when the deadbolt is extended the blocking element is automatically moved to the position blocking the moveable member. A latch lever operatively connects the deadbolt moving means and the locking lever when the blocking element is in the blocking position for moving the blocking element out of the blocking position by operation of the first moving means. The first deadbolt moving and latch retracting means may comprise a key-operated cylinder.
Also according to the present invention, a security mechanism for a mortise lock is provided. The mortise lock is of the type comprising a housing for accommodating the lock components including the security mechanism, a latch bolt and deadbolt mounted in the housing for movement relative to the housing between extended and retracted positions, first means for moving the deadbolt between the retracted and extended positions of the deadbolt, second means, including a moveable member, for moving the latch bolt and the deadbolt to the retracted position, a blocking element mounted in the housing for movement between a first position and a position where the blocking element prevents movement of the moveable member, and a locking lever operatively connecting the deadbolt and the blocking element so that when the deadbolt is moved from the retracted position to the extended position of the deadbolt element is moved to the blocking position. The security mechanism comprises an arm member integral with the locking lever and a latch lever which operatively interengages the first moving means and the arm member when the blocking element is in the second position of the blocking element and the deadbolt is in the retracted position of the deadbolt so that the blocking element is moveable to the first position by operation of the first moving means.
In accord with the present invention, a latch assembly c

Affiliated with

Also associated with

Rating

Mortise lock does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Mortise lock, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mortise lock will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2851238