AU660389B2 - Door latch and lock - Google Patents
Door latch and lock Download PDFInfo
- Publication number
- AU660389B2 AU660389B2 AU63067/94A AU6306794A AU660389B2 AU 660389 B2 AU660389 B2 AU 660389B2 AU 63067/94 A AU63067/94 A AU 63067/94A AU 6306794 A AU6306794 A AU 6306794A AU 660389 B2 AU660389 B2 AU 660389B2
- Authority
- AU
- Australia
- Prior art keywords
- cam
- latch
- bolt
- spindle
- follower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Lock And Its Accessories (AREA)
Description
1 DOOR LATCH AND LOCK 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 .1 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 avoided 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 key, from the outside in cases of emergency.
Brief Summary of the Invention It is therefore an object of the present invention to provide a door latch and/or lock which meets at least some of the above requirements.
Accordingly, the invention provides a door latch comprising: a bolt movable between an extended position and a retracted position; a first rotatable spindle adapted to be rotated by a handle on a first side of the latch and to move said bolt between said extended and retracted positions upon such rotation; a second rotatable spindle which is mechanically isolated from the first spindle and which is adapted to be rotated by a handle on a second side of said latch and which also moves said bolt upon such rotation; t oo.. a first cam provided on said first spindle; a second cam provided on said second spindle; a first follower adapted to be activated by said first cam; and a second follower adapted to be activated by said second cam, both said followers engaging the bolt.
In one embodiment the invention provides locking means for selectively locking said second spindle against rotation, said locking means being actuable only from the second side of the lock.
.In a preferred embodiment, the first and second spindles are arranged to rotate about the same axis.
I Preferably, the bolt is biased t.owards the extended position so that rotation of one of the spindles is required to move the bolt to the retracted position.
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 which: Figure 1 is a cross-sectional view through a first embodiment of the lock according to the invention.
IN:\LBMM00149:BFD Figure 2 is an exploded plan view of the movable member.
Figure 3 is a plan view and end view of the follower.
Figure 4 is a plan view and an end view of one of the guide plates.
Figure 5 is a plan view and a side view of the tongue.
Figure 6 is a plan view of the locking cams or plates.
Figure 7 is a plan view of the cam which activates the follower.
Best Mode and Other Embodiments of the Invention As shown in Figure 1, a door lock 10 of the present invention comprises a first case half 11 and a second case half 12. The first case half 11 may be located, for example, on the interior of a train guard's compartment door and the second case half 12 may be located on the outside of the compartment door. As will be appreciated from the following description, the door on which the latch and lock 10 is mounted may always be opened from the inside.
In a preferred embodiment, the first or inside c',se half 11 is internally subdivided by a slide plate 13. A detail of the slide plate 13 is shown in Figure 4. Note that the slide plate further comprises a central web 40 which is characterised by a central opening 41 which serves as a journal. The web 40 is bordered along its longitudinal side edges by rails or guides 42. A longitudinal slot 43 extends from one lateral edge toward the central opening 41.
The central opening 41 is capable of journaling two separate cams 30, 31.
Preferably, both cams have square central openings which are adapted to receive the separate square spindles 15, 16 which extend toward the plate 13 from each of the handles 17, 18. Each camrn is typically provided with a symmetrical lobes 32. This cam is shown in Figure 7. When a handle is rotated, its respective cam also rotates so that one lobe 32 or the other impinges on the back 34 of a follower In a preferred embodiment each lobe 32 can impinge on a ridge 134 formed across the follower 35 and shown in Figure 3.
Figure 3 illustrates the follower in more detail. As shown there, the follower comprises a central opening 36 which fits around a cam. The cam acts on the ridge 34 of the follower. The rear 37 of the opening 36 is rounded to tolerate the sliding of the cylindrical cam body 135. The front 38 of the follower 35 is adapted to engage a rear portion of the tongue 57.
A detailed drawing of the tor.ue 50 is shown in Figure 5. Figures and 2 illustrate how the single tongue is engaged by the two separate followers 35. In this particular example, the front 38 of the follower 35 is presented with a gap 39 which is flanked on either side by a raised shoulder 51. This arrangement of gap 39 and shoulder 51 create a carriage for the rear portion of the tongue 50. As shown more clearly in Figure 5, the tongue 50 comprises a bevelled front portion 52 and a T-shaped rear 57.
The rear 53 further comprises a shank 54 in which there is formed a central opening and a tail 56 which is characterised by projections which extend on either side of longitudinal recesses 58 which tlank the body 54.
As shown in Figures 1 and 2 the shoulders 51 of both followers 35 engage the tail 56 of the tongue 50 by abutting against or engaging the projections 57.
A small upstanding post 60 projects from an inner surface of the first case half 11.
A resilient compression spring or the like 61 extends between the post 60 and the bevelled front 52 of the tongue 50. In use, the spring 61 rests within the central opening 55 of the tongue 50. Thus, when either handle is rotated, a lobe 32 of a cam impinges on and retracts a follower 35. The retraction of the follower 35, because of the engagement between the follower and the tongue, likewise causes the retraction of the tongue against the resilient bias imposed by the spring 61. Additional return springs may be interposed between the rear 34 of the follower 35 and the rear 65 of the first case half 11. A flat "S" type spring 66 (not shown) may be used for this purpose. Thus, when the handle is released, the tongue and other moving parts return to the position depicted in Figure 1 under the influence of the springs 61, 66.
In preferred embodiments, the two main spindles 15, 16 are co-linear and drive similar cams which are journalled into the same opening 41. This simplifies the design and allows two identical followers 35 to be used in a symmetrical arrangement with respect to the slide plate 13.
It will be appreciated from the previous description that the tongue 50 is inidependently operable from either handle 17, 18 and that the handles operate independently of one another owing to the separate spindles 15, 16. Because it is intended that the interior handle 17 never lock, it is unnecessary that the first case half 11 be provided with a key opetated lock. However, it may be advantageous to key lock the outside handle 18. To this effect, the spindle 16 associated with the outside handle 18 is provided with a locking plate cain 70. An adjacent lock mechanism 71 runs parallel to the spindle 16 and is also provided with a locking plate or locking cam 72. The adjacent cams 70, 72 are shown in Figure 6. Both cams are generally round, having a similar maximum radius which is interrupted, preferably, by a single feature. As shown there, one of the cais 70 is provided with a scallop or recess 73 feature while the other cam 72 *is provided with a flat spot 74 feature. As can be appreciated from the top portion of S, Figure 6, when the flat spot 74 faces the other cam 70, the cam 70 is free to rotate. This allows operation of the tongue 50 from the outside handle 18. When the flat spot 74 is rotated out of position as shown in the bottom portion of Figure 6, the cam 70 is immobilised and therefore the spindle 16 is inoperative.
S•Note that in a preferred embodiment, the first case half 11 is provided with a recess ,0 which like the channel formed by the guides 42 on the slide plate 40, is adapted to receive a reciprocating follower 35. In this way, undesirable rotation or cocking of the IN:ALiBMM00149:BFD 4 individual followers 35 is prevented, one follower being laterally guided by the recess the other by the guides 42.
While the invention has been described with reference to particular details of construction, these should be understood as having been provided by way of example and not as limitations to the scope or spirit of the invention.
Claims (7)
1. A door latch comprising: a bolt movable between an extended position and a retracted position; a first rotatable spindle adapted to be rotated by a handle on a first side of the latch and to move said bolt betwf .n said extended and retracted positions upon such rotation; a second rotatable spindle which is mechanically isolated from the first spindle and which is adapted to be rotated by a handle on a second side of said latch and which also moves said bolt upon such rotation; a first cam provided on said first spindle; a second cam provided on said second spindle; a first follower adapted to be activated by said first cam; and a second follower adapted to be activated by said second cam, both said followers engaging the bolt.
2. The latch of claim 1, wherein: each cam further comprises two lobes wherein rotation of the cam in either direction will activate the follower on which it impinges.
3. The latch of either of claims 1 or 2, wherein: the follower further comprises a central opening through which a body of the cam passes and an upstanding shoulder on which either lobe of a cam may impinge.,
4. The latch of any one of claims 1-3, wherein: the latch further comprises a first case half; the case half being subdivided by a slide plate; the slide plate further comprising a central opering which is adapted to journal both cams. The latch of any one of claims 1-4, further comprising: a locking mechanism, the locking mechanism further comprising a first locking cam mounted on said second spindle and a second locking cam mounted on an adjacent lock body; the first locking cam characterised by a peripheral recess; the second locking cam being characterised by a peripheral flat spot; wherein rotation of the first locking cam is inhibited by the second locking cam unless the 00•°go •flat spot is adjacent the first locking cam. The latch of claim 5, wherein both cams apart from their respeetive recess or flat spot are circular.
7. The latch of any one of claims 4-6, wherein the slide plate further comprises a longitudinal slot which serves as a guide for the bolt.
8. The latch of any one of claims 1-7, wi.zrein: the bolt further comprises a central opening; Sa compression spring is located within the opening; 6 the compression spring being resiliently biased when the bolt is retracted.
9. A latch substantially as hereinbefore described with reference to the drawing figures. DATED this Twenty-eighth Day of March 1995 Clift Engineering (Oberon) Pty Limited Patent Attorneys for the Applicant SPRUSON FE-RGUSON 149tBFD DOOR LATCH AND LOCK Abstract The invention relates to a door lock or closure (10) wherein the bolt (50) is operable from either of two independent spindles (15, 16). In a preferred embodiment, each of the spindles bears a cam (30) and both cams activate independent followers Each of the followers (35) engages the bolt ee g* *e o 9 i. o Fiur* oo [N:\LIBMM00149:LMM
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU63067/94A AU660389B2 (en) | 1991-12-06 | 1994-05-12 | Door latch and lock |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AUPK9915 | 1991-12-06 | ||
AU63067/94A AU660389B2 (en) | 1991-12-06 | 1994-05-12 | Door latch and lock |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU29901/92A Division AU655692B2 (en) | 1991-12-06 | 1992-12-04 | Door lock |
Publications (2)
Publication Number | Publication Date |
---|---|
AU6306794A AU6306794A (en) | 1994-08-11 |
AU660389B2 true AU660389B2 (en) | 1995-06-22 |
Family
ID=3747941
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU63067/94A Expired AU660389B2 (en) | 1991-12-06 | 1994-05-12 | Door latch and lock |
Country Status (1)
Country | Link |
---|---|
AU (1) | AU660389B2 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU156028B2 (en) * | 1952-11-12 | 1953-01-15 | National Brass Company | Key in knoblock |
AU6044880A (en) * | 1980-07-16 | 1982-01-21 | Masco Building Products Corpoation | Latch/bolt lock |
AU605727B2 (en) * | 1988-02-08 | 1991-01-17 | Yale Security Inc. | Door lock having disengaged outer lever handle when in the locked condition and means to bias the handle toward horizontal position |
-
1994
- 1994-05-12 AU AU63067/94A patent/AU660389B2/en not_active Expired
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU156028B2 (en) * | 1952-11-12 | 1953-01-15 | National Brass Company | Key in knoblock |
AU6044880A (en) * | 1980-07-16 | 1982-01-21 | Masco Building Products Corpoation | Latch/bolt lock |
AU605727B2 (en) * | 1988-02-08 | 1991-01-17 | Yale Security Inc. | Door lock having disengaged outer lever handle when in the locked condition and means to bias the handle toward horizontal position |
Also Published As
Publication number | Publication date |
---|---|
AU6306794A (en) | 1994-08-11 |
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