Claims
- 1. In a combination type lock having a hollow base containing a central plunger, a reset surface on the base, a circular surface fixed with respect to the base and having a plurality of notches therein, a plurality of lock plungers carried by the central plunger for movement relative thereto in an axial direction, each said lock plunger having a portion capable of being contained within a respective said base notch to thereby inhibit rotation of the central plunger but each said lock plunger also having a notch, so arranged that there is a plane which, if all said plunger notches lie therein, the lock plungers cease to inhibit rotation,
- improvements whereby the lock plungers are equally spaced from one another on a pitch circle, except for one blank space, said central plunger being guided for both rotational and slidable movement in the hollow base, a selection knob obscuring the lock plungers, means guiding the selection knob for rotational and axial slidable movement with respect to the central plunger, and a push pin carried by the selection knob operable to selectively depress said lock plungers, but when located over said blank space, said push pin being operable to depress said central plunger together with said lock plungers, abutting the lock plungers against the reset surface, and thereby effect reset of the lock plungers in said central plunger.
- 2. Improvements in a combination type lock according to claim 1 wherein said circular surface is the inner peripheral surface of an inwardly directed annulus carried by the base.
- 3. Improvements in a combination type lock according to claim 1 or claim 2 wherein said selection knob is a cup-like member having a skirt which partly shrouds the central plunger.
- 4. Improvements in a combination type lock according to claim 3 wherein a push member comprises a pin carried by the cup-like member and directed inwardly, and positionable above each of the lock plungers and said blank space in turn upon rotation of the selection knob.
- 5. Improvements in a combination type lock according to claim 1 further comprising a knob return spring located between the selection knob and the central plunger.
- 6. Improvements in a combination type lock according to claim 5 further comprising a base spring between the central plunger and the base which is stiffer than the knob return spring.
- 7. Improvements in combination type lock according to claim 1 wherein the central plunger has a stem which extends through the base, and further comprising a headed stem which extends through the selection knob, the head of which constrains axial sliding movement of the selection knob, and a fastener extending through the central plunger releasably retaining the headed stem to the central plunger.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| PG2563 |
Nov 1983 |
AUX |
|
BACKGROUND OF THE INVENTION
This invention relates to a combination lock of the same general type described in the specification which accompanied our (now abandoned, but published) Australian Patent Application No. 77731/81 dated the Nov. 20, 1981.
1. Field of the Invention
In that said specification there was described a combination type lock having a hollow base containing a central plunger, bearing surfaces between the base and central plunger guiding the plunger both for rotational and slidable movement, an annulus carried by the base and having a plurality of notches in a peripheral edge, a plurality of lock plungers carried by the central plunger for movement relative thereto in an axial direction, each lock plunger having a portion of its surface capable of being contained within a respective annulus notch which thereby inhibits rotation of the central plunger, but each lock plunger also having a notch intermediate its ends arranged that, upon selective depression of the lock plungers from initial positions, all of the lock plunger notches lie in the same plane as the annulus such that the lock plungers cause to inhibit rotation of the central plunger, and means to reset the lock plungers to their initial position.
2. Description of the Prior Art
A data bank search revealed also U.S. Pat. No. 4,191,035 HATCH; U.K. Patent No. 1,530,861 STANDEN; and U.S. Pat. Nos. 3,937,046 WANG; 3,910,078 S-B MANUFACTURING CO. LTD.; 4,176,533 NORDENDALE; 4,274,272 WANG; 4,266,415 CLARKE; and U.K. patent Nos. 1,566,017 MILLIKEN and 1,503,526 DANILIN. Of these, the most pertinent appear to be HATCH and STANDEN, but in all prior art known to the applicants, the ends of the lock plungers were visible from the exterior of the lock, and although extremely difficult to pick, it is nevertheless still possible to pick such a lock, and this possibility increases with age as some of the lock plungers would appear more polished than others due to consistent use.
The main object of this invention is to provide further improvements which will still further increase the difficulties of picking a combination lock of the type described, and in an embodiment of this invention a combination lock of the type generally described in that said specification is further characterised by a selection knob which extends over the lock plungers to obscure them, the selection knob being guided for rotational and axially slidable movement with respect to the central plunger, and having a push pin by which it can selectively depress the lock plungers.
More specifically, this invention consists of improvements in a combination type lock having a hollow base containing a central plunger guided for both rotational and slidable movement therein, a circular surface fixed with respect to the base and having a plurality of notches therein, a plurality of lock plungers carried by the central plunger for movement relative thereto in an axial direction, each said lock plunger having a portion of its surface capable of being contained within a respective said base notch to thereby inhibit rotation of the central plunger but each said lock plunger also having a notch, so arranged that there is a plane which, if all said plunger notches lie therein, the lock plungers cease to inhibit rotation, said improvements comprising a selection knob obscuring the lock plungers, means guiding the selection knob for rotational and axial slidable movement with respect to the central plunger, and a push pin carried by the selection knob operable to selectively depress said lock plungers.
It is important that the lock should not be readily breakable such that, by merely shearing the lock plungers, the central plunger becomes rotatable and thereby can operate a lock. In another embodment of this invention each of at least some of the lock plungers is provided with a pair of spaced notches, one of which extends to its inner end and is engageable with a cylindrical surface, each notch having a flat surface which divides the respective lock plunger into a semi-circular portion, and this arrangement maintains better strength than the arrangement which was described in our earlier said application.
PCT Information
| Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
| PCT/AU84/00245 |
11/23/1984 |
|
|
7/24/1985 |
7/24/1985 |
| Publishing Document |
Publishing Date |
Country |
Kind |
| WO85/02438 |
6/6/1985 |
|
|
US Referenced Citations (10)
Foreign Referenced Citations (6)
| Number |
Date |
Country |
| 8388 |
Aug 1922 |
AUX |
| 66315 |
Jan 1948 |
DKX |
| 845500 |
May 1939 |
FRX |
| 466937 |
Jun 1937 |
GBX |
| 376547 |
May 1973 |
SUX |
| 438767 |
Jan 1975 |
SUX |
Non-Patent Literature Citations (1)
| Entry |
| Australian patent application Ser. No. 77,731/81 filed on Nov. 20, 1981 and published on May 27, 1982. |
Patent Grant
4718260
