Lock for runners, particularly runners of sliding glass doors, on display-window cases

Abstract

A lock for the runners, particularly for runners of sliding glass doors on a display case which comprises a box-like housing including at the front sliding glass doors. A locking bolt is displaceable in axial direction and is adapted to enter into a bolt opening of another overlapping, opposing runner. A locking cylinder is operatively connected with the locking bolt, and a device is arranged for moving the locking bolt from its advanced bolt engagement position into its open position independently of the locking cylinder.The present invention relates to a lock for runners, particularly those of sliding glass doors or showcase windows, having a locking bolt on a first runner which can be displaced in axial direction and which engages in a bolt opening of another overlapping mating runner and with which a lock cylinder is coordinated.The one known lock for runners, a lock cylinder and a locking bolt are arranged parallel to one another in a common housing. The latter is fastened to one runner. In the open position of the lock, either with the key engaged in the lock cylinder or removed from it, the locking bolt releases the other runner. From this position the locking bolt can be pressed inwardly by hand in the bolt engagement direction, into a position in which the bolt is locked. The release of the locking bolt can be effected by the key which fits the lock cylinder. This construction has various disadvantages in use. During daytime operation with super vision of the display cases available in a store or office, if the locking bolt is in the locked position, the required key must always be sought out in order to release the locking bolt by means of the lock cylinder. However, if the locking bolt were left continuously in its open position, this could permit possible theft of the articles stored within the showcase even with supervision, since the open position of the locking bolt is obvious. This known development also permits possible misuse by, for instance pressing, the locking bolt without authorization, inwards.It is one object of the present invention, to provide a lock of a construction which is advantageous in use and designed so that the locking bolt has two bolted positions, namely locked-bolted and apparently locked-bolted, in addition to an unbolted position.It is another object of the present invention, to provide an improved lock for runners, particularly runners of sliding glass doors, on display window cases, which includes a locking bolt which is displaceable in axial direction and enters into a bolt opening of another overlapping, opposing runner, and has a locking cylinder operatively connected with the locking bolt. Means are also provided for moving the locking bolt from its advanced bolt engagement position into its open position independently of the locking cylinder.As a result of this development, a lock of this type which is of a construction which is advantageous in use is created. The lock in accordance with the present invention is characterized by three positions of closing (engaged-locked, engaged-unlocked and disengaged). These provide on the one hand the closed or truly locked position (truly locked-bolted), the "apparently bolted" position (apparently locked-bolted), and the open position of the lock. The locking bolt can only be brought out of the closed engaged-locked position (truly locked-bolted) of the lock when the locking bolt is released by means of the key corresponding to the lock cylinder. However, the locking bolt then still remains in an engaged-unlocked position (apparently locked-bolted). To be sure, it is only an "apparently bolted" position. This cannot be recognized from the outside. Only the sales personnel can know that the device is in an unlocked position. In this way it is possible for them to bring the locking bolt, without the use of a key, from this engaged-unlocked or "apparently bolted" (apparently locked-bolted) position into the open position by a simple manipulation. The open or disengaged position is then visible. This provides assurance to a great extent that after the sliding glass doors have been moved together, the sales personnel will not forget to bring the lock into the "apparently locked-bolted" position or the truly locked-bolted position. The parts for the construction of the present invention are simple. They are also trouble-free. The radially protruding lug of the locking bolt fulfills a multiple function: on the one hand it serves as stop for the axial movement of the locking bolt in the direction of release. On the other hand it secures the locking bolt against rotation in its released position. This has the advantage, that when the sliding doors are pushed closed, the stop for the locking bolt can enter unimpeded into the bolt opening corresponding to it. Furthermore, this locking lug secures the "apparently locked bolted" position, in which it rests against the bottom plate of the housing. In addition to this, the locking lug also serves as a stop for the rotation of the locking bolt in cooperation with the locking slide which is actuatable by the lock cylinder. The idle stroke, or lost motion which is provided in the eccentric drive, permits a favorable construction of the lock cylinder with only one position of withdrawal for the key. With the key removed, it can therefore not be noted in the "apparently locked-bolted" position of the lock what position the locking cylinder is in. The possibility of pushing the locking bolt into its "apparently locked bolted" position serves further the purpose of securing the lock. In order to be able to turn the locking bolt at all in this position, it must be pressed inwards by a certain amount. Only after this step can the locking bolt be turned. This fact further impedes unauthorized tampering.

Description

Claims

1. A lock for sliding doors comprising:

a housing mounted on one of said doors and having an opening alignable with a bore provided in the other of said doors;

a bolt receivable in said housing in line with said opening and receivable in said bore, said bolt being rotatable in said housing and axially shiftable therein while being provided with a lateral locking projection;

means in said housing forming an abutment for said projection restraining said bolt from axial withdrawal from said bore in one angular position of said bolt and permitting axial withdrawal in another angular position of said bolt;

a locking slide shiftable in said housing transversely of said bolt and engageable in one position of said slide with said projection for preventing rotation thereof while permitting such rotation in another position of said slide;

a locking cylinder mounted in said housing parallel to said bolt and adapted to receive a key, said cylinder being rotatable to shift said slide; and

an actuating handle on said bolt operable from the exterior of said housing to rotate said bolt and selectively engage said projection with said abutment and release said projection from said abutment.

2. The lock defined in claim 1, further comprising an eccentric drive between said cylinder and said slide adapted to allow angular loss motion of said cylinder through about 180.degree. between the drive of said cylinder and said slide.

3. The lock defined in claim 1, further comprising a detent for retaining said bolt in at least one of its angular positions, said abutment being formed by a bottom plate of said housing, said bolt being axially shiftable upon engagement of said projection by said bottom plate in an amount equal to the depth of engagement of the detent.