Detachably Fixed Cylinder Lock Core

Abstract

A cylinder lock core mechanism for insertion into and becoming detachably fixed to a lock housing under control of a special key operating upon a special tumbler in the key plug, the core being retained by a slidable retaining lug emerging through the surface of the core and being retractable by operation of the special key's rotation to cause the tumbler to coact with the retaining lug permitting the core to be withdrawn from the housing -- including a deadlock member coacting with the retaining lug under control of the key plug and guiding studs in the core structure whereby the member is cammed to free the retainer for movement only upon rotation of the key plug by the special key.

Description

BACKGROUND OF THE INVENTION

Conventional cylinder locks carried by doors and the like frequently are required to be changed for security purposes, or for changing combinations; consequently, it is desirable to have an arrangement whereby the lock core may be removed without taking out the lock housing. This has brought about the so called "removable core" type of lock similar to that illustrated in U.S. Pat. No. 1,964,787 wherein a special key operating upon a special tumbler coacts with the mechanism to permit the lock core to be removed from its housing for replacement.

As also shown in U.S. Pat. Nos. 1,986,676 and 2,122,478 the mechanism normally involved is essentially a latch or cam extending from the core into a cavity of the housing under control of the key plug's rotation in combination with a special key fitted to the plug.

SUMMARY OF THE INVENTION

The present invention relates to an improved type of removable core having a positive and simplified mechanism for detachably fixing the lock core in the lock housing with the further improvement of a "deadlatch" mechanism whereby the lock can not be picked readily by rapping or the like. More specifically, a sliding type of core retainer, or latch, is provided to emerge from the core to engage the lock housing and an auxiliary member coupled to the retainer is positively confined to a position between the key plug and the core structure until the key plug is rotated thereby holding the retainer in locked position in the housing.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the removable core and the lock housing into which it is detachably fixed.

FIG. 2 is a sectional view of the mechanism within the core which is key operated to provide for the emerging of the core retainer into the lock housing.

FIG. 3 illustrates the functioning of the mechanism of FIG. 2 in order to withdraw the core retainer from the lock housing.

FIG. 4 is a detailed perspective of the principal structure of the retainer and its auxiliary member coupled thereto.

FIG. 5 is a sectional view taken longitudinally of the core structure to illustrate the action of the key and key plug in cooperation with both the actual locking tumblers and the special tumbler for controlling the core retaining mechanism.

DETAILED DESCRIPTION

Referring to FIG. 1 a cylindrical lock housing 10 is provided with an hour-glass shaped opening into which a lock core 11 may be inserted axially under control of a key 12 and a key plug 13 to cause a retainer lug 14a to engage a recessed portion within the lock housing 10. As shown in FIG. 1 a rotation of the key 12 clockwise will cause the lug 14a to emerge from the core 11 and a counter-clockwise rotation of the key will cause the lug to be retracted into the core. Obviously when the lug 14a has emerged from the core 11 and has entered the housing 10 recesses portion the core can not be removed.

Referring now to FIG. 2, which is a sectional view taken transversely through the core 11 (when it has been inserted into the housing 10) just forward of the lug 14a, it is to be noted that the lug is in its emerged position with the recessed portion 10a of the housing 10. Attention is also invited to FIG. 4 to understand the internal structure of the core 11, which consists of the retainer 14 having having the lug 14a at one end and having a pin 14b at the opposite end loosely joined to a T-shaped member 15. When the core 11 is in its retained position, therefore, as shown in FIG. 2, the retainer 14 is confined by some studs 16 and 17 at its upper edge and by the key plug 13 at its lower extremeties. However, since the retainer 14 is pinned to the member 15, which is rigidly held between the stud 17 and the key plug 13, the core 11 remains firmly in its retained position. In other words, the member 15 provides a deadlatch against random displacement of the retainer 14.

Reference is now made to FIGS. 2, 3 and 5. It is well known in the prior art to use a special key, such as key 12 having an extra tip 12a for coacting with a special tumbler such as tumbler 18, wherein the special key also operates the normally operative lock tumblers, such as the tumblers 22 and their risers 21 (See FIG. 5) to lock and unlock the mechanism. The tip 12a in the present invention functions to cause the special tumbler 18 to be cammed out of the key plug 13 (See FIG. 2) so that rotation of the key 12 (counter-clockwise as in FIG. 2 and FIG. 3) causes the tumbler 18 to move against the toe of retainer 14, which via the pin 14b pulls the member 15 to be cammed downward by the stud 17 as rotation of the key plug 13 permits the free end of member 15 to enter the cavity 13a in the key plug 13 (See FIG. 3) so that the lug 14a is withdrawn from the recessed portion 10a of the housing 10, and the core 11 can then be withdrawn from the housing.

To replace the core 11 into the housing 10 a reverse procedure is followed, the key being rotated clockwise whereby the retainer 14 is slided to the right (as viewed in FIG. 2) and the lug 14a again emerges from the core 11 and slide into the recessed portion 10a.

The key normally used to "lock" and "unlock" the lock does not have an extra tip such as the tip 12a, and under some conditions as the key plug 13 is turned the lower end of member 15 may begin to enter the cavity 13a; however, such action will not move the retainer 14 without a positive movement of tumbler 18 (e.g., per key tip 12a), a detent 23 may be provided to retain member 15 normally in the position shown by FIG. 2. Similarly, a spring (not shown) may be provided to retain tumbler 18 normally seated in the key plug 13, permitting the tumbler 18 to emerge only when cammed by the key tip 12a.

A unique feature of the invention resides in the combination of the retainer 14 and the member 15 wherein the former is positively locked into the housing 10 by its coupling with member 15 which is confined between the stud 17 and the key plug 13 so that rapping, or other vibrations tending to release the retainer lug 14a from the recessed portion 10a, has no effect in reducing the security of the lock.

Claims

What is claimed:

1. A cylinder lock core capable of being detachably fixed within a lock housing comprising a key plug, a slidable retainer for engaging a recessed portion of said housing, said retainer being constrained within said core by a pair of guiding studs and said key plug, a tumbler within said key plug capable of being displaced by introduction of a key into said plug to engage and move said retainer upon rotation of said key, and a member coupled to said retainer for locking positively said retainer against random movement.

2. The invention claimed in claim 1 wherein said coupling member is confined between said guiding studs and said key plug.

3. The invention according to claim 2 wherein said coupling member is released from said confinement through a coacting notch in said plug as the latter is rotated by said key.