GB2137688A

GB2137688A - Rack bolts

Info

Publication number: GB2137688A
Application number: GB08408955A
Authority: GB
Inventors: John Anthony Banham
Original assignee: Banham Patent Locks Ltd
Current assignee: Banham Patent Locks Ltd
Priority date: 1983-04-07
Filing date: 1984-04-06
Publication date: 1984-10-10
Also published as: GB8408955D0; GB2137688B

Abstract

A rack bolt comprises a racked shoot (2) mounted in a carrier (4) and a lock mechanism (14) mounted in a housing (16), the carrier and housing being received in mutually transverse bores in a door and the housing having an aperture (20) through which the carrier passes, so retaining the housing against withdrawal from its bore. The lock mechanism is connected to the shoot by engagement of key and keyway elements (24, 26) during the insertion of the carrier into said aperture. <IMAGE>

Description

SPECIFICATION Rack Bolts This invention relates to key-operated rack bolts, in which a bolt or shoot is thrown and withdrawn by means of a rack and pinion mechanism which can be operated by a key, e.g. through a cylinder lock mechanism.

According to the invention, there is pro vided a key-operated rack bolt comprising a racked shoot slidably mounted in a rack car rier and a housing containing a lock mecha nism for sliding the shoot, said lock housing having a tranverse aperture, and said carrier and housing being arranged to be inserted into mutually transverse bores in a door or the like with said carrier projecting into said hous ing aperture, thereby retaining the housing against withdrawal from its bore, and with the racked shoot operatively connected to the lock mechanism.

Preferably, engagement means for said con nection between the racked shoot and the lock mechanism comprise respective rotary elements in the carrier and the housing that can be aligned with each other to be placed in operative juxtaposition by the insertion of the rack carrier into said housing aperture, whereupon rotation of the lock mechanism extends and retracts the shoot. Thus, the rack carrier may mount a pinion engaging the rack of the shoot and having a coupling portion projecting transversely from the carrier, and the lock mechanism may comprise a cooperating coupling portion engagable with the pinion coupling portion by the insertion of the rack carrier axially into its bore.

Prior to said rotation of the rack carrier, it may be arranged that the pinion coupling portion is disposed within a projection of the cylindrical cross-section of said lock housing such that the bore made to receive the housing also provides clearance for the movement of said pinion coupling portion with the rotation of the rack carrier.

Preferably, the carrier is initially insertable with its engagement element angularly offset, with respect to the rack axis, e.g. by 90" from its final position and it can be slid axially into its bore to bring its engagement element into abutment with the lock housing, at which stage the element is located in the lock housing bore to permit the carrier to be rotated in order to align the respective engagement elements and permit them to be brought into engagement after a further axial movement of the carrier into its bore. It may be arranged that such axial movement itself brings the elements into engagement, e.g. by employing complementary key and keyway elements that are both aligned parallel to the carrier axis during the insertion of the carrier.

One embodiment of the invention is illustrated in the accompanying schematic drawings, in which: Figures 1 to 3 are front, side and plan views of a key-operated rack bolt according to the invention in position in a door, and Figure 4 is a sectional view on the line IV-IV in Fig. 1.

The rack bolt comprises a bolt or shoot 2 mounted for sliding movement in a carrier 4 in the form of a generally cylindrical circular cross section casing with an end plate 6 which in a conventional manner is let in flush in the edge of a door and has screws 8 passing through it to secure the carrier in place. The bolt or shoot 2 has a series of teeth 10 formed on it to provide a rack which is engaged by a pinion 1 2 mounted in the carrier 4 so that rotation of the pinion throws and withdraws the shoot 2.

The pinion is operated by a cylinder lock mechanism 14 in a housing 16, having a cylindrical cross-section of greater diameter than the carrier 4 and with a parallel pair of flats 18 formed on opposite flanks at its inner end region. In the region of the flats 18, a transverse aperture 20 extends through the casing. A rotary driver 22 projects from the lock mechanism into the aperture 20, coaxially with the housing and the cylinder of the lock mechanism. The pinion 1 2 is located in the aperture 20 coaxially with the driver and the driver and pinion are connected together through a radial key and keyway 24, 26 so that they are constrained to rotate together, but when they extend parallel to the shoot axis, as shown in Fig. 4, they are able to move relative to each other axially of the shoot 2.

To assemble the rack bolt in place, a first hole is drilled in the edge of the door to receive the bolt 4 with a sliding fit, and a smaller diameter hole is drilled directly above or below this to provide a clearance for the key portion 24 of the rack pinion 1 2 that projects beyond the radius of the rack carrier cross-section. A larger hole is then drilled in the face of the door to receive the housing 1 6 with its cylinder lock mechanism 14, the cylindrical housing being a sliding fit in that hole.

The housing 1 6 is put in place first and its aperture 20 is aligned with the rack carrier hole. With the lock cylinder keyway 26 oriented parallel to the axis of the rack carrier hole, the rack carrier can be slid into its hole and through the aperture 20, the carrier having its outer surface so formed as to leave a clearance for the keyway portion 26 of the friver 22 projecting into the aperture. This sliding movement stops when the projecting key portion 24 of the rack pinion abuts the side of the housing 16.

The projecting key portion 24 is now located in the space between a flat 1 8 and the drilling for the housing 16. This allows the rack carrier to be rotated through 90 degrees to bring the key portion 24 opposite the keyway portion 26, the carrier housing 4 having a suitable part-peripheral relief to avoid fouling the keyway portion of the driver 22 projecting into the aperture 20. The parts are now in a position in which the key and keyway are aligned as shown in Fig. 4 and they are automatically interengaged when with a final axis movement the rack carrier is inserted fully home and is secured in place by the screws.

An escutcheon 32 may be fitted on the face of the door over the lock cylinder housing 1 6 for appearance sake, but is not required to secure the lock in place. This is done simply by the rack carrier which occupies the aperture 20 and thereby fixes the housing 1 6 firmly in the door. Since the carrier 4 is inserted through the edge of the door and is therefore inaccessible when the door is locked, that provides an extremely secure arrangement which can only be circumvented if the door itself is destroyed.

Claims

1. A key-operated rack bolt comprising a racked shoot slidably mounted in a rack carrier and a housing containing a lock mechanism for sliding the shoot, said lock housing having a transverse aperture and said carrier and housing being arranged to be inserted into mutually transverse bores in a door or the like with the carrier projecting into said housing aperture, thereby retaining the housing against withdrawal from its bore, and with the racked shoot operatively connected to the lock mechanism.

2. A rack bolt according to claim 1 wherein the carrier extends through the housing.

3. A rack bolt according to claim 1 or claim 2 wherein engagement means for said connection between the racked shoot and the lock mechanism comprise respective rotary elements mounted in the carrier and the housing and arranged to be placed in operative juxtaposition by insertion of the rack carrier into the housing aperture while said elements are in alignment with each other.

4. A rack bolt according to claim 1 or claim 2 wherein the lock housing has a recessed face at said aperture for abutment with an engagement element projecting transversely from the rack carrier during insertion of the carrien, said element being disposed within the projection of the cross-section of the lock housing in the direction of its bore so that the carrier is rotatable in the housing bore to bring said engagement element into and out of alignment, in the axial direction of the carrier, with a cooperating element of the lock mechanism, said elements being then interengaged by continued insertion of the rack carrier into its bore.

5. A rack bolt according to claim 4 or claim 5 wherein the carrier is rotatable about its axis through 90 while its projecting engagement element lies within the projection of the housing cross-section, said element being displaceable thereby between a plane containing the axes of the carrier and the housing, in which plane it is aligned with the cooperating lock mechanism element, and a plane perpendicular thrust.

7. A rack bolt according to any one of claims 4 to 6 wherein said engagement element of the lock mechanism extends into the projection of the cross-section of the rack carrier and the carrier has a recess around at least part of its periphery to accommodate said lock mechanism element during said rotation of the rack carrier.

8. A rack bolt according to any one of the preceding claims wherein complementary key and keyway elements are provided for said connection of the shoot and lock mechanism.

9. A rack bolt according to any one of claims 4 to 8 wherein corresponding recessed faces are provided at opposite ends of the lock housing aperture.

10. A key-operated rack bolt constructed and arranged for use and operation substantially as described herein with reference to the accompanhing drawings.