GB2194583A - Locking means for a capstan latch mechanism - Google Patents

Abstract

A simple arrangement applied to the shaft 11 of a capstan latch mechanism comprises a rod 14D having a fork 14 member which can be brought into or out of locking engagement with a correspondingly shaped portion 13 on the shaft. As shown a solenoid 15 is employed to move the rod 14D, with a manual back-up lever 18 being provided. <IMAGE>

Description

SPECIFICATION Locking means for a capstan latch mechanism This invention relates to a heavy security lock such as that used in a blast door and is an improvement in means to lock the door by a simple arrangement applied to the shaft of a capstan latch mechanism.

According to the present invention there is provided a security lock comprising a rod having a fork member which can be brought into or out of locking engagement with a correspondingly shaped portion on a shaft.

The rod may be moved manually by means of a suitable linkage or it may be moved in and out of its locking position by means of an electrically actuated solenoid.

The invention will be more fully understood from the following description of an embodiment given by way of example only with reference to the Figures of the accompanying drawing in which: Figure 1 is a front elevation, partially in cross-section of improved means for locking a blast door and is shown in the locked position; Figure 2 is a side elevation, also partially in cross-section, of the improved locking means of Fig. 1.

Referring to the Figures, a blast door 10 is fitted with a capstan latch mechanism, not shown, that operates from a shaft 11. Keyed to the shaft 11 by a key 12 is a collar 13 provided with opposed chordal recesses 13A.13B. These recesses 13A and 13B are retained in the upright position when locked by the prongs 14A and 14B of a sturdy twoprong fork member 14 welded at 14C to a rod 14D which acts as the inner core of a solenoid coil 15. The rod 14D is moved into the unlocked position, not shown, by electrical energy being applied to the solenoid 15, and returns to the locked position by the force of gravity. When in the unlocked position, a microswitch 16 is actuated by the prong 14A of the fork member 14, giving an electrical indication at an observation point that the latch mechanism is unlocked.Conversely, when in the locked position with the prongs 14A and 14B respectively engaged in the recesses 13A and 13B of the shaft collar 13, the prong 14B actuates a microswitch 17, indicating the locked condition at the observation point. The rod 14D may alternatively be moved into the locked position by a first order lever 18 having a fulcrum 18A fixed to the blast door 10 and co-operating with a pin-slot mechanism 18B of which the pin is fixed to the upper part of the rod 14D.

The solenoid 15 is housed in a steel casing 19 which is bolted to the blast door 10 by means of four heavy holding bolts 20.

The operation of the locking means is elementary yet effective and fool-proof. To lock the blast door 10 the lever 18 is used to lower the prongs 14A and 14B of the rod 14D into the recesses 13A and 13B. The closed microswitch 17 indicates to the user at a remote position that the door is in fact locked. To unlock the door, the solenoid 15 is actuated by a direct current source, not shown, and the rod 14D is thereby raised, the two prongs 14A and 14B being withdrawn from their respective recesses 1 3A and 1 3B and the capstan latch mechanism, not shown, can be turned by the shaft 11 to unlock the blast door 10.

1. A lock comprising a rod, a shaft, and means for moving the rod, the rod having a fork member which said means can bring into or out of locking engagement with a corresponding shaped portion on the shaft.

2. A lock as claimed in Claim 1, wherein the fork member has two prongs which engage in two opposed chordal recesses provided in the shaft.

3. A lock as claimed in either of Claims 1 and 2, wherein the means for moving the rod are selected from an electrically actuated solenoid, earth gravity, suitable mechanical linkage, or a combination thereof.

4. A lock as claimed in any one of Claims 1 to 3, which is additionally provided with means to indicate the locked or unlocked positions to the use at a remote position.

5. A lock substantially as hereinbefore described with reference to the accompanying drawings.

6. A security arrangement including a lock as claimed in any one of Claims 1 to 5 and as described herein.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Locking means for a capstan latch mechanism This invention relates to a heavy security lock such as that used in a blast door and is an improvement in means to lock the door by a simple arrangement applied to the shaft of a capstan latch mechanism. According to the present invention there is provided a security lock comprising a rod having a fork member which can be brought into or out of locking engagement with a correspondingly shaped portion on a shaft. The rod may be moved manually by means of a suitable linkage or it may be moved in and out of its locking position by means of an electrically actuated solenoid. The invention will be more fully understood from the following description of an embodiment given by way of example only with reference to the Figures of the accompanying drawing in which: Figure 1 is a front elevation, partially in cross-section of improved means for locking a blast door and is shown in the locked position; Figure 2 is a side elevation, also partially in cross-section, of the improved locking means of Fig. 1. Referring to the Figures, a blast door 10 is fitted with a capstan latch mechanism, not shown, that operates from a shaft 11. Keyed to the shaft 11 by a key 12 is a collar 13 provided with opposed chordal recesses 13A.13B. These recesses 13A and 13B are retained in the upright position when locked by the prongs 14A and 14B of a sturdy twoprong fork member 14 welded at 14C to a rod 14D which acts as the inner core of a solenoid coil 15. The rod 14D is moved into the unlocked position, not shown, by electrical energy being applied to the solenoid 15, and returns to the locked position by the force of gravity. When in the unlocked position, a microswitch 16 is actuated by the prong 14A of the fork member 14, giving an electrical indication at an observation point that the latch mechanism is unlocked.Conversely, when in the locked position with the prongs 14A and 14B respectively engaged in the recesses 13A and 13B of the shaft collar 13, the prong 14B actuates a microswitch 17, indicating the locked condition at the observation point. The rod 14D may alternatively be moved into the locked position by a first order lever 18 having a fulcrum 18A fixed to the blast door 10 and co-operating with a pin-slot mechanism 18B of which the pin is fixed to the upper part of the rod 14D. The solenoid 15 is housed in a steel casing 19 which is bolted to the blast door 10 by means of four heavy holding bolts 20. The operation of the locking means is elementary yet effective and fool-proof. To lock the blast door 10 the lever 18 is used to lower the prongs 14A and 14B of the rod 14D into the recesses 13A and 13B. The closed microswitch 17 indicates to the user at a remote position that the door is in fact locked. To unlock the door, the solenoid 15 is actuated by a direct current source, not shown, and the rod 14D is thereby raised, the two prongs 14A and 14B being withdrawn from their respective recesses 1 3A and 1 3B and the capstan latch mechanism, not shown, can be turned by the shaft 11 to unlock the blast door 10. CLAIMS

1. A lock comprising a rod, a shaft, and means for moving the rod, the rod having a fork member which said means can bring into or out of locking engagement with a corresponding shaped portion on the shaft.

2. A lock as claimed in Claim 1, wherein the fork member has two prongs which engage in two opposed chordal recesses provided in the shaft.

3. A lock as claimed in either of Claims 1 and 2, wherein the means for moving the rod are selected from an electrically actuated solenoid, earth gravity, suitable mechanical linkage, or a combination thereof.

4. A lock as claimed in any one of Claims 1 to 3, which is additionally provided with means to indicate the locked or unlocked positions to the use at a remote position.

5. A lock substantially as hereinbefore described with reference to the accompanying drawings.

6. A security arrangement including a lock as claimed in any one of Claims 1 to 5 and as described herein.