GB2274134A

GB2274134A - Locking mechanism

Info

Publication number: GB2274134A
Application number: GB9225804A
Authority: GB
Inventors: Hiroshi Okuda
Original assignee: TOTAL PROD SALES Ltd
Current assignee: TOTAL PROD SALES Ltd
Priority date: 1992-12-10
Filing date: 1992-12-10
Publication date: 1994-07-13
Anticipated expiration: 2012-12-10
Also published as: GB2274134B; GB9225804D0

Abstract

A look operating mechanism has a locking bolt and a rotatable member to extend and retract the bolt. A first member 13 rotates with the rotatable member and acts to pivot a second member 22, which is connected to move the bolt, about an axis 23. The rotation of member 13 is limited by a stop 15 thereon engaging the member 22. A member 30, pivoted at axis 32 and carrying a bolt, can be pivotally connected to member 22 at a point 31 spaced further from axis 23 than axis 32. <IMAGE>

Description

LOCKING MECHANISM This invention relates to a locking mechanism in which a bolt is extended or retracted in response to an operating mechanism. The operating mechanism may be operable in response to a security device, which may be a key or a security code-operated mechanism or it may be operable in response to a simple handle which can be operated by anybody.

The invention is concerned with the part of the operating mechanism which converts rotational movement of one member into the extension or retraction of the locking member. According to one aspect of the invention, there is provided a lock operating mechanism having a locking bolt, a rotatable member rotatable to extend and retract the locking bolt, a first member rotatable with the rotatable member and a second member rotatable about an axis by engagement with the first member, the first member being provided with a stop for engaging the second member so that the rotation of the first member is limited, the locking bolt being movable in response to movement of the second member.The first member may be provided with a pair of stops, for engaging the second member on rotation in respective directions, for limiting rotation of the first member within a range of angles about a central position.

The first member may be provided with a probe and the second member may be provided with a recess into which the probe can extend, the probe moving out of the recess on rotation of the first member. The stop of the first member may engage the mouth of the recess to prevent further rotation of the first member.

The locking bar may be movable through a lever arrangement to provide increased movement of the locking bar in response to a given movement in the same direction of the second member.

According to another aspect of the invention there is provided a locking mechanism comprising a shaft rotatable to operate the mechanism, a locking bolt and a linkage between the mechanism and the bolt, the linkage comprising a first lever pivotable about a first axis in response to rotation of the shaft, a second lever pivotable about a second axis which forms part of or is connected for movement with the locking bolt, the second lever being hinged to the first lever about an axis which is further from the first axis than from the second axis. In either aspect of the invention spring means may be provided to bias the mechanism so that on movement from an inoperative position of the bolt, the mechanism is biased to move the bolt to its operative position.

An example of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side elevation of a locking mechanism; Figure 2 is a front elevation of the mechanism of Figure 1; Figure 3 is a front elevation of part of the interior of the mechanism; Figure 4 is a front view of the cam of Figure 3 with engaging levers in their rest position; Figure 5 shows the components of Figure 4 in a different position; Figure 6 shows the components of Figure 5 with a transverse locking bolt, and Figure 7 shows the components of Figure 6 with a hook bolt.

The mechanism shown in the drawings is the interior portion of a security locking mechanism. The exterior portion, not shown, includes an operating mechanism operable only by people with the appropriate security device or code and operation of the exterior device rotates shaft 11 shown in the present drawings. A knob 12 is mounted on the shaft 11 for an operator on the inside of the door to operate the mechanism and this knob can be turned by any operator, without using a security device or code.

Within the interior portion is a cam 13 mounted on the shaft 11 for rotation therewith. It has a central probe 14 which in the rest position of the mechanism extends along the longitudinal axis 17 of the housing. The probe 14 flows into an approximately circular portion of the cam coaxial with the shaft 11 but shoulder stops 15 are provided at the ends of the diameter transverse to the probe 14. A return spring 16 is provided to return the cam 13 to its rest position with the probe 14 extending vertically upward when the knob 12 is released.

The probe 14 extends into a socket 21 of a lever 22 pivotable about a stub shaft 23 extending from the front plate 19 of the interior portion casing 18 on the longitudinal axis 17 of the mechanism, the mouth of the recess being arranged to engage one or other of the shoulders 15 on the cam as the cam rotates. The mouth is shaped so that on rotation of the cam the probe moves from the recess towards the side of the mouth remote from the edge engaging the shoulder stop.When the The remote wend 24 of the lever is pivoted by a pin 54 to a spring loaded arm 25 loosely mounted in a slot 26 in the casing 18, a coil compression spring 27 being mounted around the member between the sides of the slot and a shoulder 28 on the member which spring assists movement of the lever on rotation of the cam from its central rest position which is therefore a position of unstable equilibrium.

Thus as the cam 13 is rotated either way from its central rest position, the spring 27 will assist corresponding rotation of the lever 22 away from its central position in the corresponding direction.

A hook bolt 30 is pivoted to the lever 22 by a slot aperture 31 at its pivot axis with the arm 25 to rotate about a stub shaft 32 on the rear plate 33 of the casing 18. The relative positions of the stub shafts and pivot (the shaft 55 is closer to the pin 54 than the shaft 23) provide magnification of the angle of rotation of the hook bolt relative to the angle of rotation of the shaft 11. A stub shaft 34 on the bolt 30 extends through a slot 35 in a transversely sliding bolt 36, the length of the slot 35 accommodating the relative divergence of the transverse path of bolt 36 (at right angles to the longitudinal axis) and the arc centred on the shaft 32.

The bolt 36 thus moves transversely with the hook bolt 30.

The mechanism contains the following components, working from the front rearwards: The front plate 19, formed with a stub shaft 23 and a shaft aperture 53 for receiving the shaft 11 on which the knob 12 is mounted; the hook bolt 30 formed with a central aperture 55 to fit on the stub shaft 32, the lower stub shaft 34 and the upper slot aperture 31 which engages the pivot pin 54 at the end of the lever 22; the locking bolt 36 formed with the central slot 35 for receiving the shaft 34 on the hook bolt 30; the lever 22 and cam 13; and the rear plate 56 of the mechanism formed with a stub shaft 57 about which the bolt 30 pivots.

The stub shafts 34 and 23 are aligned in the central rest position of the apparatus but not connected.

As the cam 13 is rotated, the bolts 30 and 36 move transversely from the casing 18 to enter a suitable stop plate, the bolt 30 having a hooking action suitable for a sliding door, and the bolt 36 being conventional. The mechanism can thus be used with doors opening towards or away from the operator of the mechanism, or on sliding doors, and the two bolts 30 and 36 provide double strength locking on hinged doors. The bolts can move in either direction in response to appropriate rotation of the cam 13, so that the locking mechanism is not handed.

Claims

1. A lock operating mechanism having a locking bolt, a rotatable member rotatable to extend and retract the locking bolt, a first member rotatable with the rotatable member and a second member rotatable about an axis by engagement with the first member, the first member being provided with a stop for engaging the second member so that the rotation of the first member is limited, the locking bolt being movable in response to movement of the second member.

2. A mechanism as claimed in claim 1 wherein the first member is provided with a pair of stops, for engaging the second member on rotation in respective directions, for limiting rotation of the first member within a range of angles about a central position.

3. A mechanism as claimed in claim 1 or claim 2 wherein the first member is provided with a probe and the second member is provided with a recess into which the probe can extend, the probe moving out of the recess on rotation of the first member.

4. A mechanism as claimed in claim 3 wherein the stop of the first member engages the mouth of the recess to prevent further rotation of the first member.

5. A mechanism as claimed in any one of the preceding claims wherein the locking bar is movable by the second member through a lever arrangement to provide increased movement of the locking bar in response to a given movement in the same direction of the second member.

6. A locking mechanism comprising a shaft rotatable to operate the mechanism, a locking bolt and a linkage between the mechanism and the bolt, the linkage comprising a first lever pivotable about a first axis in response to rotation of the shaft, a second lever pivotable about a second axis which forms part of or is connected for movement with the locking bolt, the second lever being hinged to the first lever about an axis which is further from the first axis than from the second axis.

7. A mechanism as claimed in any one of the preceding claims wherein spring means is provided to bias the mechanism so that on movement from an inoperative position of the bolt, the mechanism is biased to move the bolt to its operative position.

8. A locking operating mechanism substantially as hereinbefore described with reference to the accompanying drawings.