AU776119B2

AU776119B2 - A lock mechanism

Info

Publication number: AU776119B2
Application number: AU42081/01A
Authority: AU
Inventors: Allan Brady
Original assignee: Tyco Water Pty Ltd
Current assignee: Viadux Pty Ltd
Priority date: 2000-05-04
Filing date: 2001-05-04
Publication date: 2004-08-26
Anticipated expiration: 2021-05-04
Also published as: AU4208101A

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: A LOCK MECHANISM Applicant: WANG INDUSTRIES PTY LTD Thcfllng statement is, aul ecrpio f-hs nenin The following statement is a full description of this invention, including the best method of performing it known to me: 1 Documen3 2 A LOCK MECHANISM The present invention relates to a lock mechanism and is principally although not exclusively for use to lock covers which are applied to sewer pits or storm water drains. It will be convenient therefore, to describe the invention in relation to that particular application, although it is to be appreciated that the invention will have wider application and could apply for example in relation to many different forms of closures for closing an opening. For example, a lock mechanism according to the invention could apply to a door or cupboard closure, or to closures such as are found in shipping containers.

In relation to sewer pits and storm water drains, it is preferable that the closures for these be lockable, so that they cannot be opened by unauthorised persons. However, the lock mechanism for such closures is preferably very simple and durable and has high resistance to corrosion and clogging, such as by inundation with slit, dirt, mud etc.

The requirement for simplicity is partly to encourage relocking of the closure when access to the sewer pit or storm water drain is no longer required.

Additionally, it is preferred that the lock mechanism be such as to indicate to personnel who replace the closure, that the lock mechanism used to lock the closure in place is activated. A problem with some known lock mechanisms, is that the relevant personnel may inadvertently or deliberately neglect to lock the closure so that it can subsequently be removed by unauthorised persons.

It is an object of the present invention to provide an improved lock *...*mechanism which overcomes or alleviates at least some of the problems with prior art mechanisms. It is a further object of the invention to provide a lock mechanism which includes an indication that the mechanism has been locked.

A lock mechanism according to the present invention includes a lock housing, and a latch bolt located within the lock housing which is moveable between an extended locked position and a retracted unlocked position. A key is provided for operating the lock mechanism, which key has engagement means for engaging the latch bolt for moving it between the extended and retracted positions. The arrangement is such that the key cannot be removed from engagement with the latch bolt when the latch bolt is in the unlocked position.

W-SHARON~ndri n Wl15855.0c 3 A lock mechanism according to the invention can have a very simple form. In one embodiment, the housing of the lock mechanism is formed as part of the closure it is operable to lock. In one preferred arrangement, the latch bolt is of elongate extent and is snugly located within a bore formed in an edge or wall of the closure, the latch bolt being displaceable within the bore between the locked and unlocked positions. In this arrangement, in the locked position, one end of the latch bolt extends into an opening in the frame which supports the closure. Retraction of the latch bolt to remove the end thereof from the bore of the frame supporting the closure disposes the latch bolt in the unlocked position.

In the above arrangement, the key of the lock mechanism is insertable in a second bore in the closure which intersects with the bore containing the latch bolt so that the key may be inserted into the second bore for engagement with the latch bolt. In a preferred arrangement the first and second bores are 15 disposed perpendicular to each other along axes that do not intersect, with each of the bores being arranged to snugly receive the respective latch bolt and key.

The first and second bores could alternatively be disposed other than perpendicular to each and that may be preferable in some applications of the invention to permit easy key access.

S* 20 The latch bolt and the key include cooperable engagement means which cooperate to displace the latch bolt preferably upon rotation of the key. The cooperable engagement means can take any suitable form and in one form, the :..key includes first and second engagement sections for engaging the engagement means of the latch bolt and the arrangement is such that only the first engagement section of the key can facilitate engagement with and disengagement from the engagement means of the latch bolt. By this arrangement, when the second engagement section of the key is engaged with the engagement means of the latch bolt, advantageously the key cannot be removed from the lock mechanism. Thus, the lock mechanism can be arranged so that retraction of the latch bolt to the unlocked position can only occur after sufficient rotation of the key has brought the second engagement section thereof into engagement with the engagement means of the latch bolt. As such, in the unlocked position, the key cannot be removed from the lock mechanism and thus the key provides a visual indication that the lock mechanism is in an W:%SHAR ON\Ar 5s15855 .dc unlocked condition. To remove the key from the lock mechanism, the operator must rotate the key to retumrn the first engagement section thereof to engagement with the engagement means of the latch bolt, which returns the latch bolt to the extended locked position. Therefore, the arrangement is such that the key can only be retrieved from the lock mechanism by the operator by relocking the closure relative to the supporting frame.

In a preferred arrangement of the invention, the key has an elongate form and includes a plurality of longitudinally extending splines preferably at one end thereof, which are arranged to engage a grooved or toothed section of the latch bolt, such that rotation of the key causes displacement of the latch bolt.

The key is preferably cylindrical and preferably the splines extend circumferentially about one end thereof. The splines may be disposed about the full circumference of the key, or about a portion only of circumference. The circumferential extent of the splines is dependent on the required travel of the latch bolt and the diameter of the key.

In the above arrangement, the first engagement section of the key includes one or more splines that extend fully to and open into the distal end of the key. In the second engagement section, the splines terminate prior to the distal end of the key, so as to be closed at the distal end. As such, splined engagement between the key and the latch bolt can only occur when the key is introduced for engagement with the latch bolt through the first engagement section. After that engagement, rotation of the key may occur to displace the latch bolt and that rotation will bring the second splined engagement section of the key into engagement with the grooved or toothed section of the latch bolt and because the splines of that second engagement section terminate prior to the distal end of the key, attempts to remove the key from engagement with the latch bolt fail, because the closed ends of the splines jam relative to the grooved or toothed section against further disengaging movement.

In one form of the invention, the grooved or toothed section of the latch bolt is formed by a plurality of axially spaced circumferentially extending rings with grooves of reduced diameter formed between each ring. Alternatively, the grooved or toothed section of the latch bolt may be formed by a toothed rack arrangement and this might be most applicable if the latch bolt is of square or W..SHdROc,, WP d re 15M' 1 SSda rectangular cross-section. Alternatively shaped latch bolts may also be provided with the groove or toothed section formed appropriately.

The arrangement of the invention advantageously additionally permits the key to be used as a handle to lift the closure out of the supporting frame when the latch bolt has been retracted to the unlocked position. The use of the key as a handle is available by virtue of the non disengageable engagement between the engagement means of the respective key and latch bolt when the latch bolt is in the unlocked position. Advantageously, the key may therefore be inserted into the lock mechanism for retraction of the latch bolt to the unlocked position and then used as a handle to lift the closure out of its seated position within the supporting frame. Of course, the materials of both the key and the latch bolt must be able to support the load of the closure for use of the key as a ~handle to be viable. It is envisaged however, that both the key and latch bolt would normally be manufactured from metal, which would have the required load capability. Alternatively, it is equally possible that the key and/or the latch bolt might be manufactured from other materials, such as plastics and in that circumstance, use of the key as a handle may not be vilable.

If the key is to be used as a handle, it may be configured to include a suitable gripping area which facilitates secure hand gripping and in a very simple form, the lever may include a bore extending transversely to the longitudunal axis thereof and located toward the end of the key opposite to the engagement means thereof. A cross member may be inserted into the bore and gripped by the operators figures for lifting the closure. Alternatively, the of the key may be formed with its own handle type configuration for gripping purposes.

To ensure secure locking of the closure within the supporting frame, it is preferable that the closure include a pin which is acceptable within a bore formed in the supporting frame which is spaced from and preferably substantially opposite to the latch bolt and which may be fixed relative to the closure against movement. By this arrangement, the closure will be fixed to the frame at two points, when the latch bolt is extended into the locked position.

Without such a pin, it may be possible to lift and pivot the closure from a position substantially opposite the latch bolt and to cause removal of the latch W ASHARON ritewpvs1615855 doc 6 bolt from its bore within the supporting frame without its withdrawal from the unlocked position by the key.

The invention may be used with closures having any particular shape as long as the closure fits into a supporting frame against which, or within which, the latch bolt can extend to engage. Thus, the closure may be circular, square, rectangular or otherwise shaped. In relation to closures for sewer pits and storm water drains, the closure advantageously generally includes a planar main section and a peripheral edge which extends perpendicular to the main section generally in a direction into or toward the pit or drain and the latch bolt may be housed within the closure in a bore which extends through the peripheral edge. Likewise, the bore for accepting the key can be formed in the peripheral edge and that is advantageous from a closure lifting point of view, **Idbecause the closure can be lifted from one edge thereof to pivot about the other *edge.

15 It is essential to the above described embodiment of the invention that g.

the respective bores for accommodating the latch bolt and the key intersect in such a manner that the key is only able to engage the latch bolt when it is oriented so that the first engagement section engages the grooved or toothed section of the key. Advantageously, the operator can easily orient the key suitable for this engagement, simply by turning the key until it properly registers with the grooved or toothed section. Thereafter, the key can be further rotated to displace the latch bolt as required.

The attached drawings show an example embodiment of the invention of the foregoing kind. The particularity of those drawings and the associated description does not supersede the generality of the preceding broad description of the invention.

Figure 1 is a part plan view of a closure 10 incorporating the lock mechanism according to the present invention. The particular closure shown is a sewer pit closure or lid and Figure 2 shows that lid as installed relative to a supporting frame. With reference to each of these figures, the closure 10 is of generally circular configuration and includes a main planar section 11 and a peripheral edge section 12. As shown in Figure 2, the peripheral edge section 12 includes a downwardly depending section 13 which has a lower surface 14 and an edge surface 15. The closure 10 is supported in a frame 16 which is W \S-ARONWrlre vsN185855 docc partly shown in Figure 2 and which is formed to define a recess 17 for snug receipt of the peripheral edge section 12, as shown. The above described arrangement is well known and commonly used for providing a closure for sewer pits and storm water drains. The closure 10 is commonly made of metal or a combination of metal and infilled concrete while the frame 16 is generally formed of concrete.

As shown in Figures 1 and 2, a locking pin 18 and a counter pin 19 extend between the closure 10 and the frame 16 according to the invention and in the arrangement shown in Figure 2, the closure 10 is locked within the frame 16.

In the arrangement of Figure 2, the peripheral edge section 12 includes bores 20 and 21 for accommodating each of the locking and counter pins 18 ~and 19. The bore 20 extends fully through the peripheral edge section 12, so that each end of the locking pin 18 extends outwardly of the edge section 12, while the bore 21 is a closed bore, so that only one end of the counter pin 19 .:.extends from the edge section 12. As will be explained hereinafter, the locking pin 18 is arranged for axial displacement within the bore 20, while the counter pin 19 is fixed against movement relative to the bore 21.

Removal of the closure 10 from the frame 16 requires the locking pin 18 to be displaced radially inwardly, so that the end 22 of the pin 18 is released from accommodation within the bore 23 formed in the frame 16. By that release, the closure 10 may be lifted to pivot about the opposite edge and by that movement, and by slight shifting movement of the closure 10 to release the counter pin 19 from the bore 21, the closure can be removed from the frame 16.

Figures 3 to 7 illustrate the arrangement by which displacement of the locking pin 18 within the bore 20 can be achieved. With reference to Figure 3, a key 24 of generally cylindrical, elongate extent is provided. The key 24 includes a locking pin engagement end 25 which is configured for engagement with an engagement section 26 of the locking pin 28, which is shown in Figure 4. The engagement end 25 is splined and includes a first engagement section 27 and a second engagement section 28. The engagement section 27 includes a spline or splines which extend fully to the distal end 29 of the locking pin 18. The second engagement section 28 includes splines which terminate prior to that distal end 29.

W %SHARON nreMproMvsW15855.doc 8 The arrangement of the first and second engagement sections 27 and 28 is such as to permit the engagement end 25 to be brought into engagement with the section 26 of the locking pin 18, by virtue of the splines of that section 27 extending to the distal end 29 of the pin 18. It is not possible for the second engagement section 28 to be brought into engagement with the engagement section 26 until after that section 26 has been engaged by the first engagement section 27, because the splines of the second engagement section 28 terminate prior to the distal end 29 of the pin 18.

The arrangement of Figure 5 is also shown in Figure 6 but taken through the cross-section VI. In Figure 6, the locking pin 18 is shown engaged with the splines of the first engagement section 27. Rotation of the key 24 in an anticlockwise direction will cause the splines to mesh with the engagement section 26 and to displace the locking pin 18 to withdraw it from the bore 23. As shown in Figure 6, the bore 20 in the peripheral edge section 12 intersects with the bore 30 which accommodates a portion of the key 24 and receipt of the locking pin 18 and the key 24 within the respective bores 20 and 30, is a snug fit. Thus, as explained earlier, it is not possible for the second engagement section 28 to engage the engagement section 26 of the locking pin 18 until that section 26 has first been engaged by the first engagement section 27, because the pin 24 is restricted against movement which would allow such engagement.

Accordingly, the key 24 can only engage the pin 28 when the splines of the first engagement section 27 are oriented suitably to engage the section 26 of the locking pin 18, as shown in Figure Upon rotation of the key 24 in an anti-clockwise direction, the pin 18 is retracted from the bore 23 of the frame 16 and that retracted position is shown in Figure 1. That rotated position is also shown in Figure 7 and in that figure it can be seen that the first and second engagement sections 27 and 28 of the key 24 have been rotated. Also, it can be seen that the pin 24 cannot be withdrawn from the bore 30 because the splined engagement of the second engagement section 28 with the engagement section 26 of the locking pin 18 will not permit withdrawal. Accordingly, the key 24 can be used to lift the closure 10 and to assist with that, a finger grip cross-bar 31 may be provided.

The arrangement of the invention provides a very simple locking mechanism. The parts of the mechanism are extremely robust, and the bores W:%SHARONW%Pt 5855.doc 9 to accommodate the mechanism, which become the housing of the mechanism, can be formed in the casting process which is normally used in the manufacture of such components as closures for sewer pits and storm water drains. The operation of the lock mechanism is also extremely simple, such that an operator is required only to insert the key 24 in the bore 30, rotate the key until the first engagement section 27 meshes with the engagement section 26 of the locking pin 18 and then rotate the key 24 to withdraw the locking pin 18 from the bore 23 formed in the frame 16. The closure 10 can then be removed with the key 24 remaining in place. When the closure is replaced, the key is rotated in the reverse direction to cause the pin to engage again within the bore 23 and thus the closure is locked against unauthorised removal.

Even if an operator was to remove the key 24 after removal of the closure 10 from the frame 16, by rotating the key 24, that rotation would extend the locking pin 18 so that the closure could not be reinstalled in the frame 16 15 until the key 24 was reinserted in the bore 30 and rotated to retract the locking pin 18. Thus, a major benefit of the present invention is that it minimises or potentially eliminates the possibility that the closure 10 could be reinstalled in the frame 16 and left unlocked.

A further advantage of the invention, is that a single key can be employed by a single operator to unlock any number of closures which have cooperating lock mechanisms. Equally, the keys can be altered so that only certain keys can unlock certain closures.

A further advantage of the invention, is that the bore 30 can extend fully S through the peripheral edge section 12. As shown in Figure 2, the bore opens into the opening 32 of the frame 16, so that any road material, such as dirt, mud, gravel, etc can fall through the bore 30 and into the pit or drain without failing the lock mechanism. Thus, the lock mechanism can remain fully operational even in unclean environments.

The locking pin 18, may be held within the bore 20, by a spring loaded arrangement, which may act on the rear end 33 of the pin 18. While a suitable arrangement is not illustrated, a person skilled in the art would be able to devise such an arrangement. Alternatively, other locating devices, such as an abutment pin, may be employed to ensure that the locking pin 18 remains appropriatly positioned relative to the bore 30, for engagement by the pin 24.

W:SHARO MNdp vs%15855.doc The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description.

DATED: 4 May 2001 PHILLIPS ORMONDE FITZPATRICK Attorneys for: WANG INDUSTRIES PTY LTD W \SHARON drew\povsl615855.doc

Claims

1. A lock mechanism including: a lock housing; a latch bolt located within the lock housing which is movable between an extended locked position and a retracted unlocked position; a key for operating the lock mechanism, the key having engagement means for engaging the latch bolt for moving it between the extended and retracted positions; wherein the key cannot be removed from engagement with the latch bolt when the latch bolt is in the unlocked position.

2. A lock mechanism according to claim 1, wherein the housing is formed as part of a closure it is operable to lock.

3. A lock mechanism according to claim 2, wherein the latch bolt is of elongate extent and is snugly located within a bore formed in an edge or wall of the closure. 9

4. A lock mechanism according to claim 3, wherein the latch bolt is displaceable within the bore between the locked and unlocked positions.

5. A lock mechanism according to claim 3 or claim 4, wherein the key is insertable in a second bore in the closure which intersects with the bore containing the latch bolt.

6. A lock mechanism according to any one of the preceding claims wherein the first and second bores disposed perpendicular to each other along axes that do not intersect, with each of the bores being arranged to snugly receive the respective latch bolt and key.

7. A lock mechanism according to claim 5, wherein the latch bolt and the key include cooperable engagement means which cooperate to displace the latch bolt upon rotation of the key. m ff*Chwr M CWMAI 12

8. A lock mechanism according to any one of the preceding claims wherein the key includes first and second engagement sections for engaging the engagement means of the latch bolt such that only a first engagement section of the key facilitates engagement with and disengagement from the engagement means of the latch bolt.

9. A lock mechanism according to any one of the preceding claims, wherein the key has an elongate form and includes a plurality of longitudinally extending splines.

A lock mechanism according to claim 9 wherein the splines are arranged to engage a grooved or toothed section of the latch bolt such that rotation of they key causes displacement of the latch bolt.

11. A lock mechanism according to any one of the preceding claims wherein the key is cylindrical and the splines extend circumferentially about one end thereof.

12. A lock mechanism according to claim 11, wherein the splines are disposed about the full circumference of the key.

13. A lock mechanism according to claim 11, wherein the splines are *,disposed about a portion of the circumference of the key.

14. A lock mechanism according to any one of claims 10 to 13, wherein the grooved or toothed section of the latch bolt is formed by a plurality of axially spaced circumferentially extending rings with grooves with reduced diameter formed between each ring. A lock mechanism according to any one of claims 10 to 13, wherein the grooved or toothed section of the latch bolt is formed by a toothed rack arrangement.

W:%tonir\ayvhPmvisbnwt$UM: echam ctbm doc 13

16. A lock mechanism according to any one of claims 2 to 15, wherein the key can be used as a handle to lift the closure out of a supporting frame when the latch bolt has been retracted from the unlocked position.

17. A lock mechanism according to any one of claims 2 to 16, wherein the closure includes a pin which is acceptable within a bore formed in a supporting frame which is spaced from the latch bolt and which may be fixed relative to the closure against movement.

18. A lock mechanism according to any one of claims 2 to 17, wherein the closure is a circular shaped closure. o

19. A lock mechanism according to any one of claims 2 to 17, wherein the closure is a square shaped closure. S

20. A lock mechanism according to any one of claims 2 to 17, wherein the closure is a rectangular shaped closure. S e*

21. A lock mechanism according to any one of claims 5 to 20, wherein the respective bores for accommodating the latch bolt and the key intersect in a manner such that the key is only able to engage the latch bolt when it is oriented so that the first engagement section engages the grooved or toothed section of the key.

22. A locking mechanism substantially as herein described and illustrated. DATED: 04 May 2001 PHILLIPS ORMONDE FITZPATRICK Attorneys for: WANG INDUSTRIES PTY -LTD t W Ionia\Da in\PmMba4\lskc medhansm dm.doc