AU655692B2 - Door lock - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

O 0r IS 4 0 4a o 44400 44, 04,4 0900 o 4 D Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Clift Engineering (Oberon) Pty Limited 24/30 Bathurst Road Oberon New South Wales 2787

AUSTRALIA

Edward Graham Robertson Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Door Lock ASSOCIATED PROVISIONAL [31] Application No(s) PK9915 APPLICATION DETAILS [333 Country

AU

[323 Application Date 6 December 1991 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815/3 -2- BACKGROUND OF THE INVENTION This invention relates to door locks, and more particularly, though not exclusively, to door locks which can be restricted so as to only open from one side.

In many situations it is desirable that a person on one side of a door be able to open the door simply by turning a handle on the door in the usual way, but for the door not to be openable from the other side simply by turning the handle. For example, in recent years, guards on trains, particularly at night, have been subjected to attacks which might have been vRyoided had the door only been openable from the inside so that the attackers were not able to gain access to the guards compartment from the outside. On the other hand, it should also be possible to allow the door to be opened, for example using a special a akey, from the outside in cases of emergency.

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-3- BRIEF SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a lock which meets at least some of the above requirements.

Accordingly, the invention provides a locking mechanism comprising: a first rotating spindle; the spindle provided with a first cam; the first cam having a flat portion; a second rotating cam; the second cam having a concave portion; the cams arranged so that the second cam can rotate freely when the flat portion of the first cam is adjacent the second cam but cannot rotate when the first cam engages with the concave portion.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of a lock according to the invention will now be more fully described, by way of example, with reference to the drawings, of o* which: 0000 aoor o 0 e CSH/LMM/578E ,i

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Figure 1 is a cross-sectional plan view through a first embodiment of the lock according to the invention; Figure 2 is an exploded plan view of the movable member, two spindles and bearing means forming parL of the lock of Figure 1; Figure 3 is a side view of the movable member of Figure 2; Figure 4 is a side view of one of the spindles of Figure 2; Figure 5 shows different positions of the locking means of the lock of Figure 1; and Figure 6 is a cross-sectional plan view, similar to Figure 1, through a second embodiment of a lock according to the invention.

DETAILED DESCRIPTION OF THE DRANINGS As shown in Figure 1, a lock 1 for a door, particularly for a door for a guards compartment in a railway carriage, comprises a first part 2 for fitting to the inside of the door and a second part 3 for 15 fitting to the outside of the door.

The inside part 2 is provided with a bolt 4 which is movable between a retracted position and an extended position (as shown) in which it fits into a recess in a door frame to latch the door closed.

The bolt 4 is provided with a tail portion 5 which is engagable by a 20 forward portion 6 of a movable member 7. As best shown in Figure 3, the forward portion 6 of movable member 7 is provided with two upstanding side wings which engage the tail portion 5 of bolt 4. The movable member 7 further comprises a rear portion 9 offset from the forward portion 6. The rear portion 9 is provided with an elongated aperture 10 within which sits a bearing member 11.

The bearing member 11 comprises a central support portion 12 and two, oppositely extending butt axles 13. One of the butt axles 13 fits into a circular recess 14 in one end of an inside spindle 15, whose other end is connected to a handle 16 on the inside of the door. The inside spindle 15 can thus rotate on butt axle 13 when the handle 16 is turned. On inside handle 15, there is further provided a semi-circular cam 17 having a flat face 18 which abuts against a shoulder 19 provided on the rear portion 9 of movable member 7. Thus, when handle 16 is turned, the flat face 18 of cam 17 moves against shoulder 19 causing movable member 7 to move rearwardly and thus pull bolt 4 into a retracted position to open the door.

In a similar fashion, th other butt axle 13 fits into a recess in one end of an outside spindle 21, whose other end Is connected to

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a handle 22 on the outside of the door. The outside spindle 21 is also provided with a semi-circular cam 23 having a flat face 24 which abuts against shoulder 19 of movable member 7. Thus, when the outside handle 22 is turned, movable member 7 is caused to move rearwardly so as' to move bolt 4 to its retracted position thus opening the door. It will be appreciated, however, that inside spindle 15 and outside spindle 21 rotate complete independently of each other.

Lock 1 is further provided with a locking spindle 25 extending between the inside part 2 and outside part 3 of the lock 1. A handle 26 is provided on the inside to rotate locking spindle 25. A recess 33 is provided in outside part 3 so that access to locking spindle 25 can be obtained. Locking spindle 25 is provided with a keying recess 34, such as of square cross section, into which a square key can be inserted from the outside in order to rotate the locking spindle 25, if desired.

e oIn order to prevent the door being opened from the outside, the oo locking spin!le 25 is provided with a first locking plate or cam 27 having a flat portion 28 and a circular portion 29. Outside spindle 21 is provided with second locking plate or cam 30 having a concave portion 31 and a circular portion 32, When the bolt 4 is in its normal, closed position, outside spindle 21 is positioned so that concave portion 31 of second locking plate 30 is adjacent first locking plate 27 which interferes with its rotation, as best seen in Figure In this view, first locking plate 27 is shown in the locked 25 position with part of its circular portion 29 engaged with concave portion 31 of second locking plate 30. In this position, second locking plate 30 cannot be rotated, thus preventing outside spindle 21 from being rotated and therefore preventing the door from being opened from the outside.

When it is desired to allow the door to be opened from the outside in the normal way, handle 26 is turned so that flat portion 28 of first locking plate 27 is adjacent second locking plate 30, as shown in Figure In this position, second locking plate 30 is free to be rotated, as shown in Figure Thus, a person on the inside of the door can always freely open the door by turning handle 16 and can, by roving handle 26, select whether the door can be opened from the outside using handle 22. When IV locking spindle 25 is turned by handle 26 to the position where second Slocking plate cannot move, the door being effectively locked from the LMM/578E -6outside, it can nevertheless be opened in emergencies by inserting a suitable key into the recess in the outside end of locking spindle There is shown in Figure 6 a second embodiment of a lock according to the invention in which similar features to those shown in Figure 1 have identical reference numerals and will not be further described. In this embodiment, the third spindle 34 only extends within the outside part 3 of the lock 1 and has mounted thereon the first locking plate 27. A keyed recess 35 is provided in the end of the third spindle 34 so that a suitable key can be inserted into the recess 35 from the outside of the door in order to lock or unlock the door, for example in an emergency. The third spindle 34 does not, in this embodiment, extend to the inside part 2 of the lock nor is there a S0 handle provided on the inside to enable the third spindle to be turned 0 0 0from the inside. Such a lock could be used, for example on a lavatory 0 0: 15 door where it need only be openable, when closed, from the inside by a user, although it could be opened from the outside, in an emergency by a person with a suitable key.

Although only particular embodiments of the invention have been 0" 0 described, it will be appreciated that various modifications and 20 improvements can be made without departing from the scope of the 0 00 0 0 present invention.

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Claims (8)

1. A locking mechanism comprising: a first rotating spindle; the spindle provided with a first cam; the first cam having a flat portion; a second rotating cam; the second cam having a concave portion; the cams arranged so that the second cam can rotate freely when the Flat portion of the first cam is adjacent the second cam but cannot rotate when the first cam engages with the concave portion.

2. The locking mecnanism of claim 1, wherein the firstcam is circular but for the flat portion.

3. The locking mechanism of either of claims 1 or 2, wherein the second cam is circular but for the concave portion.

4. The locking mechanism of any one of claims 1-3, wherein: each cam has a centre and a maximum radius; and the cams are spaced together so that a distance between their centres is less than a sum of their maximum radii. .oo

5. The locking mechanism of any one of claims 1-4, wherein the S. 20 first spindle is a locking spindle.

6. The locking mechanism of any one of claims 1-5, wherein the second cam is operated by a second spindle.

7. The locking mechanism of claim 6, wherein the second spindle is attached to a handle. o: 25

8. A locking mechanism substantially as hereinbefore described with reference to Figure 0***S0 DATED this TWENTIETH day of OCTOBER 1994 S" Clift Engineering (Oberon) Pty Limited Patent Attorneys for the Applicant SPRUSON FERGUSON SMM/7E 0578E i i P SABSTRACT Door Lock A door lock comprises a bolt movable between an extended position (as shown) and a retracted position. A first rotatable spindle (15) is arranged to be rotated by a handle (16) on a first side of the lock and to move the bolt between said extended and retracted positions upon such rotation. A second rotatable spindle (21) is arranged to be rotated by a handle (22) on a second side of the lock and to move the bolt upon such rotation. A locking means 27, 30) for selectively locking said second spindle against rotation is also provided, said locking means being actuable from one or both sides of the lock This allows the bolt to be moved from handle (16) Z while handle (22) is in the locked position. W, 0 Figure 1 a 49 4 p 9t s 0 0 6 4 1 CSH/0578E