AU627495B2 - Improved rack lock - Google Patents

Description

V

AUSTRALIA

PATENTS ACT 1952 627495 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: o 040 TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Address for Service: CLYDE INDUSTRIES LIMITED 140 Arthur Street, North Sydney, New South Wales, 2001, Australia ARTHUR S. CAVE CO.

Patent Trade Mark Attorneys Level Barrack Street SYDNEY N.S.W. 2000

AUSTRALIA

0000 0# a o at *r 0 Complete Specification for the invention entitled IMPROVED RACK

LOCK.

The following statement is a full description of this invention including the best method of performing it known to me:- 1 ASC 49 G0O 1 0081 1 2/C0' '1/e.

i r 1156T/PP 0385j 1 IMPROVED RACK LOCK The present invention relates to locking devices and in particular relates to a tamper resistant locking mechanism comprising a wheel and a rack lock for use in providing locking of a member such as a door curtain against movement relative to an adjacent fixed member where the latching takes place generally at a location remote from the lock.

More particularly, the invention relates to improvements in door locks of the type employing racks or bars which enable translation of movement of the bars by a central locking cylinder including a handle to a latching "°°position. The improvements relate to the provision of a combined wheel and rack mechanism which by virtue of its configuration allows for increased travel of the racks and 15 enables a corresponding reduction of the width which is taken up by the wheel and racks when compared to the prior 0.0 art mechanisms. The locking mechanism also comprises a dead lock cylinder associated with the handle.

There are in existence a number of locks of the variety 0.0 20 known in industry as bar and rack locks. These locks 5 generally comprise at least one and preferably two racks having engaging means located on one of their ends which .engage a complementary part of an actuating handle associated with the mechanism.

In these rack locks, as the handle is turned about its axis the engagement between the knob and the part of the rack causes substantially linear movement of the rack.

Australian Patent 518869 by LOWE AND FLETCHER AUSTRALIA PTY LTD discloses one such rack lock comprising a cylinder lock, which has connected thereto extendable and retractable locking bars operable by rotation of an annular rotatable member. The lock assembly also has axially projecting members located on the rotatable member which co-operate with a shaped aperture provided on its associated locking bar.

Another such rack lock is disclosed in Australian Patent 507140 by Firma Frame Nominees Pty Ltd and comprises a latch and bar means operable by means of a movable lock A mechanism such that the latch bar is operable between a /1 p 0385j 2 position inward of the edge of a door to which it is attached and outward of the said edge so that a portion of the end of the bar engages with an engaging means associated with the door frame.

As with other locks in this class of locks the aforesaid locks suffer from significant disadvantages.

One disadvantage associated with the known rack locks is the tendancy for arcing of the racks at the central locking mechanism upon application of an axial load to the racks. This effect is created by the nature of the engagement between a projection on the locking cylinder and a recess in the locking bar, whereby rotation of the locking cylinder, when in use, tends to urge the bars radially outwards from the centre of the locking cylinder. This 15 effect is wholly undesirable and is one reason for the need to provide a wide lock housing to accommodate the prior art mechanisms.

The prior art locking arrangements including those *..referred to above have necessitated the wider than necessary oo 20 housing to compensate for the undesirable translation of axial into arcuate movement of the racks. This effect also reduces the mechanical advantage during rotation of the lock and can lead to wear of the lock at linkages and also to possible jambing against the housing in severe cases.

The prior art rack locks have been designed so as to reduce or prevent tampering with the lock by application of axial load at the extremities of the lock. Where this occurs it is disadvantagous if a weakness exists in the fittings at wear surfaces such as at pivotal connections between the bar and the central lock and also by virtue of the arcing tendancy previously described.

The prior art devices which use pivotal couplings can become sloppy at the coupling due to the fact they are primary wearing surfaces.

The action of these locking mechanisms is such that an axial force exerted on either of the rack or latch bars tends to create an unwanted turning moment about the centre of the cylinder lock.

This action that is, the turning moment generated by

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0385j 3 the handle is, when the door is properly used, a desirable action however the positive or negative (tension or compression) axial loads applied to the bars are properly generated from the central locking mechanism.

It is undesirable therefore for a rack lock to be more predisposed towards tampering by the application of axial loads at the extremities of the locking bars due to the presence of such disadvantages as worn connections and arcing. Furthermore, if rotational play exists in the rotating cylinder or if play exists in the connections between the locking bar and the cylinder this can exacerbate the disadvantages of and the predisposition towards tampering of the rack lock assembly when an axial force is improperly applied to the outward extremities of the locking bars.

In addition to the aforesaid prior art problems, a further problem has been manifest in that the hinge pins which directly or indirectly link the handle and the locking cylinder with the locking racks tend to arc and move up during load transfer between the locking racks and the handle when the locking racks are subject to applied axial loads, leading to accelerated wear. Where arcuate movement of the racks occur, the axial travel of the racks enabled by engagement between the handle and racks is rendered inefficient due to a reduction in mechanical advantage of the locking mechanism.

The present invention seeks to ameliorate the disadvantages of the prior art by providing an improved rack lock assembly having a central locking assembly which in cooperation with racks prevents unwanted rotation of the central locking assembly if and when an axial force is applied to the extremities of the locking bar such that tampering of the lock is prevented and in combination with increased travel of the racks due to an increased mechanical advantage a reduced width of the lock mechanism and housing is enabled by use of a teeth array on the racks to provide the load transfer surface for load transfer between the rack and a toothed wheel.

The invention also seeks to provide a rack lock locking 0385j 4 mechanism adapted to eliminate rotational and axial play in or about the central locking assembly or in the racks.

In one broad form the present invention comprises: a locking mechanism of the type comprising a cylindrical or substantially annular handle which is part of a central locking assembly an associated wheel, at least one locking rack which advances and retracts in response to rotational movement of said handle, characterised in that the locking mechanism is adapted with means to prevent actuation of said locking mechanism if and when an axial compressive load is applied to said locking bars at or near o athe extremities of said locking bar or bars, means to prevent arcuate movement of said racks and means to enable 1an increase in travel of said racks thereby enabling a 15 reduction in width of the locking mechanism housing.

In another form the invention comprises a tamper o resistant lock of the type comprising a central rotatable handle and associated wheel adapted to engage with advancing o e and retracting locking racks or bars which engage latching 0 20 means remote from said central rotatable handle characterised in that the tamper resistance is provided by the provision of lugs on the wheel and cam elements or o: protrusions on the locking racks such that a camming effect takes place by interaction between camming surfaces on the respective lugs and protrusions so as to prevent unwanted p rotational movement of the handle and the said racks when an axial compressive load is applied to said locking racks in a direction towards the handle.

In the broadest form the present invention comprises; a locking mechanism of the rack and pinion type comprising a central locking assembly and a pair of racks for mounting on a corrugated door curtain and which moves between a locked and unlocked mode to effect locking and unlocking of the door; the locking mechanism comprising; an annular rotatable handle for setting in the door curtain having on one side a finger grip and on the other side a wheel having associated therewith an array of teeth \.kA N grouped into two diametrically spaced sets, 0f 0385j a pair of locking racks disposed on diametrically opposite sides of the annular handle, each having an array of teeth which engages with one of the said sets of teeth, wherein at least one tooth in each set is spaced apart at a distance greater than the distance between the remaining teeth to thereby create a wide space in each tooth set, a wide space on each tooth array on the locking racks in which the said spaced apart tooth travels, separate passages along which each one of the locking bars advance and retract laterally of the handle and in S:000: opposite directions to engage fixed structures laterally of the door, :0 diametrically opposed lugs on the wheel which mutually 15 engage with respective projections on each of the locking racks when the locking mechanism is in the locked mode; wherein, when the locking mechanism is to be moved from the unlatched to the latched mode, the handle is rotated so that by virtue of the engagement between the array of teeth on each rack and the corresponding set of teeth, each locking :rack advances towards the latched mode such that when the handle is nearing the end of its rotational travel a lug and respective projection on each rack engage in such a way that if an axial force is applied to the racks, other than by the handle, return of the locking mechanism to the unlatched mode is prevented.

In the preferred embodiment the said mechanism includes at least two sets of diametrically opposed and radially extending teeth on a wheel at the back of the handle which are adapted to engage corresponding teeth in an array of k teeth on the said locking bars. Adjacent at least one tooth on the wheel are diametrically opposed lugs which engage corresponding projections or cam elements on the locking bars. This prevents unwanted actuation of the lock results in the wheel being restricted within certain limits and can only be effected by manual operation of the central locking assembly and not by the application of an inwardly directed Saxial load at the extremities of the locking bar or bars.

In the preferred embodiment the lock mechanism width to __i SI 0385j 6 rack travel ratio is dramatically reduced due principally to the elimination of arcuate movement of the racks which previously necessitated a wider housing to accommodate this.

The handle is adapted with a cylindrical dead lock which provides an unlocked mode allowing opening from the inside but preventing external opening and a deadlocked mode preventing opening from either outside or inside.

The invention will now be described in more detail according to a preferred embodiment and with reference to the accompanying illustrations wherein: Figure 1: shows an elevational view of the locking mechanism in the latched configuration; Figure 2: shows an elevational view of the locking mechanism in the open configuration.

15 Referring to figure 1 there is shown an elevational o view of a locking mechanism 1 in the latched configuration.

The locking mechanism according to the embodiment described essentially comprises a housing 2, racks 3 and 4 and a 0 handle 5. The handle 5 is adapted to sit in a recess within 20 the housing to enable rotational movement thereof. The term ee oo ohousing refers to that space within which the central locking assembly and racks are disposed and which may be bounded on one side by the door curtain itself and on the other side with a cover. Racks 3 and 4 are adapted to slide axially along passages 6 and 7 respectively, in response to rotational movement of the handle When the locking mechanism is in the latched configuration as shown in figure 1, the racks 3 and 4 are extended laterally and by engagement with extension racks 8 and 9 enable latching of a door curtain with which the lock is intended for use.

The overall concept of the rack locking mechanism as shown, is similar to the known rack lock mechanisms insofar as the use of a wheel and racks is concerned but not in the manner of operation between the protrusions or camming elements 10 and 11 on the rack locks 3 and 4 respectively and the diametrically opposed lugs 12 and 13 on th handle The rack lock also differs from the prior art rack locks in relation to the nature of the engagement between the 4 I, 0385j 7 000000 c D D o o 0 0 o 0 5 0o 0 ooo oeo Do 3 0 1)3 ooe,

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e •0~ teeth arrays and teeth sets on the wheel 14, 15 and 16 and 17 respectively.

When the locking mechanism is placed in the latched configuration, the handle is rotated by an operator such that the lugs 12 and 13 respectively on the wheel are moved into camming engagement with protrusions 10 and 11 respectively. The lugs and protrusions sit in a different plane to the plane in which the teeth arrays move so that the operation between the lugs and the protrusions are not interferred with when engagement takes place between the respective teeth arrays. When in this configuration, if any axial movement is applied to the racks 3 and 4 from the extremities thereof, the engagement between the lugs 12 and 13 and the respective protrusions 10 and 11 prevent any 15 axial movement of the rack locks and therefore any rotational movement of the central locking assembly. This provides a safeguard in the locking mechanism so that the only manner in which the locking mechanism can operate so as to be released from the latched configuration is by rotation 20 of the handle by a user of the locking mechanism.

When the locking mechanism is to be placed in the open or unlatched configuration as shown in figure 2, the handle 5 is turned in the direction of arrow 18 such that the lugs 12 and 13 disengage from protrusions 10 and 11. At the same time teeth 19 and 20 begin rotating towards surfaces 21 and 22 of the rack locks 3 and 4 respectively. This has the effect of urging each rack in opposite direction so that the teeth arrays on the racks 3 and 4 advance in a direction towards the handle. Referring to figure 2, the locking mechanism is shown in the fully open configuration.

In this configuration it can be seen that teeth array 14 engages with tooth set 15 and teeth array 16 engages with tooth set 17 via at least three of the teeth in the respective teeth sets and arrays.

Preferably, the door curtain to which the locking mechanism is attached is placed in the open configuration following a 900 arcuate movement of the handle in the direction of arrow 18. When this occurs, the extension 4. pieces 8 and 9 are freed from a latching engagement with a a.

0385j 8 fixed structure associated with the door curtain with which the locking mechanism is intended for use.

When the locking mechanism is to be returned to the latched configuration the handle is simply turned through an arc of 90 in the opposite direction to the direction of arrow 18.

The locking mechanism is also adapted with a deadlock 23 which can operate as a deadlock and this is shown in figure 1. It is intended that the lock 23 be disposed essentially within the turn knob 5 and with a key access means presenting to the exterior of the door with which the °!locking mechanism is to be used and another handle *°:presenting to the interior of the door with which the locking mechanism is to be used.

e a 15 As can be seen from figure 1, in the latched

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configuration of the locking mechanism there is no engagement between any of the teeth of the teeth and arrays and sets 14, 15, 16 or 17. This is due to the increases o spacing which exists in the array between tooth 24 and 0 20 surface 21 in rack 3 and between tooth 25 and surface 22 Ln ev •rack 4. In addition to this, the absence of a tooth from the teeth sets 15 and 16 which result in spaces 26 and 27 on the wheel facilitates the disengagement between the teeth sets and arrays when the handle is to be moved from the latched to the open configuration.

The absence of the teeth also allows engagement between the lugs 12 and 13 and protrusions 10 and 11 respectively as the handle is rotated towards the latched configuration.

The disengagement between the teeth arrays and sets, as a result of the absences of teeth in the described positions enables any applied axial load to the ends of the racks 3 and 4 to be transferred through the protrusions 10 and 11 to the lugs 12 and 13 thereby preventing any rotation of the wheel as the resultant force from an applied axial load passes through the center of the turn knob and also by virtue of the fact that the racks are not free to rotate due to restraint by the walls 28 and 29 in the housing 2. The walls 28 and 29 prevent any rotational movement in the racks which was evident in the prior art mechanisms. When jambing i t 0385j 9 between the protrusions 10 and 11 and the lugs 12 and 13 respectively occur, the only way this can be removed is to apply a positive rotational movement to the handle 5. Once the lug and cam surfaces are disengaged, the respective teeth arrays and sets begin re-engagement and thus movement of the racks 3 and 4 is achieved.

The handle 5, as previously mentioned, is adapted with teeth sets 15 and 16 The teeth sets are mounted on the wheel 30 which is disposed in an alternate plane to the plane of the lugs and protrusions.

Thus the locking mechanism employs in its operation :0:wheel gearing in order to maximise the mechanical advantage by maximising travel of the racks 3 and 4.

00 00 Figures 1 and 2 show the workings of the locking 15 mechanism by virtue of the fact that the cover plate 31 has been removed. The plate has been removed for clarity 00 however, this plate is affixed to the housing 2 by means of screws passing through holes 32 and 33 which align with holes 34 and 35 respectively when the plate 31 overlies the 0 20 mechanism. The lock is then affixed to a door (not shown) 0 via holes 36 and 37.

Due to the configuration of the locking assembly which incorporates the respective interengagement of the teeth arrays and sets, major advantages are imparted to the lock.

Firstly, there is high resistance to any movement in the wheel 30 or racks 3 and 4 if an axial load is applied to the lock at the extremities of the rack when the rack is in the latched mode. Also, there is an elimination of wearing couplings at or near the lock assembly thus, increasing the life of the lock and reducing the likelihood of wear related failures which occurred in the prior art. The elimination of at last one tooth from each of the engaging arrays enables any axial compressive force on the racks to be conveniently redirected along a line slightly eccentric or in alignment with the center of the handle via the lugs and protrusions. This, in addition to the fact that the racks travel in passages 6 and 7 eliminates any possibility of arcing of the rack. As a result of the adoption of the sets p\i of teeth 15 and 16 on wheel 30 and teeth arrays on the racks Ir;\ 0385j 3 and 4, arcing of the racks during turning of the knob is eliminated thereby enabling a considerably more narrow housing to be used in order to accommodate the locking mechanism. Thus, the use of the wheel 30 effectively eliminates the inefficiencies which result from axial force components being created by unwanted arcuate movement at pin connections as in prior art mechanisms.

A further advantage of the present invention resides in the fact that no load is taken by the locking barrell as is often the case with the prior art. This protects the lock 23 from damage during normal usage and also if the assembly is tampered with. The lock 23 comprises a locking barrell which is allowed at least 1800 rotation and allows 15deadlocking of the door when the locking mechanism is in the closed mode. The provision of the deadlocking facility in the handle 5 provides additional security from inside the door. The handle 5 is in the preferred embodiment disposed on the inside of the door and this enables opening of the D door from the inside when the lock mechanism is not deadlocked and prevents opening from the outside irrespective of whether the lock is deadlocked or not.

Due to the overall efficiency of the locking mechanism in the utilisation of the interengaging teeth, the width of the lock is reduced by at least 25 per cent in comparison to the prior art locking mechanisms. The present invention has increased efficiency over a wider arc with an increase in the mechanical advantage over that arc. The prior art mechanisms have a mechanical efficiency over a much smaller arc.

The further significant advantage of the present invention resides in the increase in travel of racks 3 and 4 over their operating range upon rotation of handle compared to the travel in the prior art locking bars. Due to the arcuate action of the prior art locking bars a compromise must be made between the width of the lock and the minimum amount of travel required. The more travel required, the wider the lock must be according to the prior art lock mechanisms. The present invention reduces the 4 -ok required width of the assembly and increases the travel by <i 0385j fr, 11 the eliminacion of the above described arcuate motion of the racks and additionally the working arc of the handle has been increased. Preferably the working travel of the bars i is 25mm however, the travel is not necessarily limited to S this amount. 1 The invention is primarily suited for use with garage doors of the variety having a rolling curtain however, it is conceivable that the locking assembly may be adapted to other types of doors.

It will be recognised by persons skilled in the art that numerous variations and modifications can be made to the present invention without departing from the overall spirit and scope of the invention as broadly described o herein.

03 00 o 0 a L I 0 4

Claims (14)

1. A locking mechanism of the rack and pinion type comprising a central locking assembly and a pair of racks for mounting on a corrugated door curtain and which moves i: 5 "fetlckn n Sbetween a locked and unlocked mode to effect locking and unlocking of the door; the locking mechanism comprising; an annular rotatable handle for setting in the door curtain having on one side a finger grip and on the other o 10 side a wheel having associated therewith an array of teeth 0: grouped into two diametrically spaced sets, 0 a pair of locking racks disposed on diametrically Sopposite sides of the annular handle, each having an array oo0 of teeth which engages with one of the said sets of teeth, :0 15 wherein at least one tooth in each set is spaced apart at a distance greater than the distance between the 0 0° remaining teeth to thereby create a wide space in each tooth set, 000 0a wide space on each tooth array on the locking racks 00000 20 in which the said spaced apart tooth travels, separate passages along which each one of the locking bars advance and retract laterally of the handle and in opposite directions to engage fixed structures laterally of the door, diametrically opposed lugs on the wheel which mutually engage with respective projections on each of the locking racks when the locking mechanism is in the locked mode; wherein, when the locking mechanism is to be moved from the unlatched to the latched mode, the handle is rotated so that by virtue of the engagement between the array of teeth on each rack and the corresponding set of teeth, each locking rack advances towards the latched mode such that when thc handle is nearing the end of its rotational travel a lug and respective projection on each rack engage in such a way that if an axial force is applied to the racks, other than by the handle, return of che locking mechanism to the unlatched Ell mode is prevented. K

2. A locking mechanism according to claim 1 wherein, when t the handle is rotated in the opposite direction, travel of P 0385j 13 the spaced apart tooth in each set within the corresponding wide space in the tooth array of each rack enables the lugs to release from the respective protrusions before the spaced apart tooth and remaining teeth on the rack and wheel interengage to retract the racks to the unlatched mode.

3. A locking mechanism according to claim 2 wherein the spaced apart tooth in each set may be created by elimination of at least one tooth between the spaced apart tooth and the remainder of the teeth in each set.

4. A locking mechanism according to claim 3 wherein each e set of teeth has a leading end and a trailing end with the o spaced apart tooth being at the trailing end.

A locking mechanism according to claim 4 wherein the spaced apart tooth of each tooth set are diametrically S 15 opposed.

6. A locking mechanism according to claim 5 wherein the .o0: array of teeth on each locking rack have a leading end and a :.OL trailing end.

7. A locking mechanism according to claim 6 wherein, when :.oo 20 the locking mechanism is moving between the unlocked and locked mode the leading end of the set and the leading end of the tooth array on the rack initially engage then progressively engage towards the trailing end of the set and array respectively to thereby urge the racks in an axial direction away from the handle. 2

8. A locking mechanism according to claim 7 wherein when the trailing ends of the sets of teeth on the wheel and the array of teeth on the racks respectively are releasing from engagement, simultaneously, the lugs on said handle engage with the respective protrusions on each of said racks, said lugs causing said racks to advance an additional distance in the direction away from said handle to a position of full advancement.

9. A locking mechanism according to claim 8 wherein, when said lugs and protrusions are fully engaged, said teeth sets and arrays on the wheel and racks respectively are Sdisengaged and at the same time, said spaced apart tooth on said wheel moves into the wide space on each rack but ilid without engaging the trailing end of the teeth array on each I L1"91 D 1* *q. r I 1 C d~~ll O *O I -7 I -1 0305j 14 rack.

A locking mechanism according to claim 9 wherein the Shandle further comprises diametrically disposed shoulders at least one of which engage a wall to thereby contain rotational movement of the handle.

11. A locking mechanism according to claim 10 wherein the said diametrically disposed shoulders of the handle restrict rotational movement of the handle to within the range of 0 0 0 to 90

12. A locking mechanism according to claim 11 wherein, when the locking mechanism is to be moved from the closed mode to the open mode, the handle is positively rotated such that the lugs and protrusions disengage thereby enabling engagement between the spaced apart teeth and the wide spaco 15 on each rack and thence progressive reengagement between the teeth sets and arrays commencing at the said trailing ends of the said teeth sets and arrays.

13. A locking mechanism according to claim 12 wherein the handle also comprises a key actuated locking cylinder 20 disposed concentrically therein.

14. A locking mechanism according to claim 13 wherein each of the locking racks have connected thereto, extension racks which enable latching where a wide door curtain is used which places the fixed structures at an extended distance from the locking mechanism. A locking mechanism as hereinbefore described and with reference to the accompanying illustrations. DATED this 29th day of May, 1992. CLYDE INDUSTRIES LIMITED By Its Patent Attorneys DAVIES COLLISON CAVE L I