NZ250127A - Door latch and handle assembly: latch and carriage with resilient mounting - Google Patents

Description

2 5 0 i p 7 Patents Form 5 Priority Date(s): Complete Specification Filed: Class: Publication Date: 2..6...MAR...199S P.O. Journal No: N.Z. No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION - 4 NOV 1993 A DOOR LATCH AND LATCH ASSEMBLY We, HAINES TECHNOLOGY PTY LTD, of 5th Floor, Trak Centre, 445 Toorak Road, Co*— Toorak, Victoria 3142, Australia,Ado hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - -1 - (Followed by 1A) 2 A POOR LATCH AND HANDLE ASSEMBLY PRIOR ART This invention relates to an improved latch assembly and an improved handle assembly and particularly such assemblies for doors, windows, gates and the like.

One known door latch assembly and handle assembly ha s a latch tongue which protrudes from the extremity of a door and when the door is in the closed position the latch tongue is held in a groove in the door surround and is unable to be opened until the handle is turned to withdraw the latch tongue. In this 10 known apparatus the latch tongue is directly connected to the handle assembly and a single spring is used to urge the latch tongue to return to the protruding position.

This type of apparatus has a single mechanism and a single spring between the latch tongue and the handle assembly thereby wear and tear 15 occurs on the one mechanism including when the handl6 Is being turned and when the door is pushed shut In the latter the latch tongue connects with the door surround and is pushed into the door in opposition to the spring so that the door is able to close. When in the closed position the latch tongue then releases Into the groove in the door surround. To cope with this wear and tear, 20 the spring is usually heavy duty. However, this results in it being difficult and noisy to merely close the door without turning the handle and requires a certain vigorous effort to force the tongue to laterally move against the resilience of the spring. This results in the door being closed roughly and a vibration of the door and Its enclosure and the applied force being directly received by the latch 25 mechanism workings.

In prior art known to Applicant, U.S. Patent specification 3,128,116 describes a pair of springs 183 and 200 to control a latch mechanism and latch bolt In a lock assembly suitable for domestic dwellings. The second spring 183 appears to be a kick off bar spring rather than a latch spring. Similarly, U.S. 30 Patent No. 3,089.720 describes springs 12 and 5 for control of a latch. This provides a latch bolt which will be retracted a predetermined distance ^nd then held under a camming influence on the strike plate to function as a friction latch, A "5/v'OV;993 2 u j i U.S. Patent No. 3,344,860 incorporates springs 46 and 41 in a door latch. It is claimed as a primary objective of the invention disclosed to simplify the installation of a lock construction of pressed steel construction. Pressed steel construction disclosed is intricate and difficult to manufacture.

Finally, U.S. Patent No. 3,222,097 discloses a secondary spring for controlling an automatic deadlock mechanism to prevent the latch bolt being released by a blade or similar tool.

In another form of latch mechanism a light spring may be used to operate the latch tongue. In these mechanisms however other spring systems need to 10 be externally applied to cause the handle or door knob to return to its normal position after the operating cycle is completed. This external system adds untidy bulk to the appearance of a door and is expensive as a whole separate mechanism is required. Furthermore, known door latch assemblies and handle assemblies are predominantly made of metal. Due to the difficulty in machining 15 metal parts, the inaccuracies in present production of metal parts, the requirement for lubricating metal latch and handle assemblies and the consequent life span of only about 10 years for metal latch assemblies and handle assemblies then replacement, maintenance and installation of these known assemblies is expensive and the product not considered to be of quality. 20 SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an Improved closure means which overcomes one or more of the aforementioned disadvantages of known mechanisms.

It is a further object of this invention to provide an improved latch 25 mechanism which overcomes one or more of the aforementioned disadvantages of known mechanisms.

It is a still further object of this invention to provide a door closure means that can be made of plastics and can take advantage of the qualities of plastics material.

According to one aspect of the Invention there is provided a latch assembly for retaining a door closed, the latch assembly comprising: i "fV a carriage means for mounting in the door and operable by ahyOpening I v means for facilitating opening of the door, connecting means connecting said carriage means with said opening means; and a latch tongue resiliently mounted to said carriage means; wherein said 5 mounting of said latch tongue to said carriage means results in the latch tongue moving with the carriage means when movement of the carriage means is effected by said opening means, said latch tongue being adapted to resiliently move relative to the carriage means upon closing of the door.

The carriage moans is slidably and resiliently mounted for movement in a casing means such that the carriage means extends substantially in the same alignment as the latch tongue and wherein said resilient mounting of said carriage means urges the carriage means to move relative to the casing means and in the opposite direction to the direction of movement of said carriage means effected by said opening means.

Preferably the resilient mounting of the carriage means to the casing means comprises a spring, said spring being located around at least a portion of the carriage means and within said casing means such that the spring acts between a surface of the carriage means and an internal surface of the casing means.

Preferably the latch tongue includes resilient arms forming said casing means adapted to house a latch tongue spring controlling movement of the latch tongue independently of the carriage means. Conveniently the resilient arms and the latch tongue are molded in one piece from moldable material as is the carriage means.

Preferably said carriage means includes two extending resilient arms, at least one of said arms having a post extending at an angle to 6aid one arm; said connecting means comprising a cam drive having a central means for connection to said opening means such that the opening means is able to rotate said cam drive, said cam drive further including parallel spaced curved lobe body portions for locating said cam drive to said carriage means; such that the extending arms of the carriage means fit between the spaced body^portions ofc the cam drive but on opposite sides of the central means of the cam drive; i "HiBigfitN 0 127 wherein said rotation of said cam drive by said opening means in one direction effects contact of at least one of said curved lobe body portions with a said post and forces the carriage means to move in opposition to the resilient mounting of the carriage means to the casing means.

Preferably the carriage means and the resilient arms of the latch tonguo are interlockabiy engaged to constrain said latch tongue spring.

Preferably the post of the arm of said carriage means and the curved lobe body portions of the cam drive are shaped and/or angled to provide a non linear amount of rotation of the cam drive relative to the amount of movement of said 10 carriage means.

Preferably the arms of the carrier means are of resilient material to allow flexing of the arms during assembly of the carriage means and casing means to allow partial pre-assembly of the latch components in one direction.

According to another aspect of the invention there is provided a handle 15 means for cooperating with a latch assembly to retract a latch tongue tha protrudes from the extremities of a door, the handle means comprising: a bearing drive shaft shaped to complement a receiving bearing surface of the latch mechanism whereby rotation of the bearing drive shaft retracts the latch tongue; a set of door handles effecting rotation of the bearing drive shaft, at least a first of said handles having an internal connecting cavity; and connecting means for connecting at least one end of the drive shaft to the first handle; said connecting means comprising at least one flexible locking means; whereby the internal connecting cavity of the at least first handle is configured to receive and lockably retain the flexible locking means, the locking means being retained within said door handle cavity by flexing when being inserted in a flexed state and the cavity being shaped such that when the locking means is fully Inserted the locking means is able to substantially and 30 resiliently return to its unflexed state and the shape of the cavity restricts tfrfe locking means from being withdrawn from the handle.

Preferably the bearing device shaft includes as least one : * / 9 v r- v--" u 6 attachment means for attaching to said connecting means, said attachment means comprising flexible arms for resilient insertion and locking in an internal cavity of said connecting means.

Preferably a cam drive aperture is provided in the cam drive and is 5 configured to allow relatively wide tolerance fit of the shaft therein.

Preferably the door opening means includes two escutcheon plate means for respectively attaching to fixing means attached to either side of said door, said escutcheon plate means locating said set of door handles but remaining fixed whilst allowing rotation of said door handles. 1 o Preferably the bearing drive shaft is made from a high strength plastics material and the connecting means and at least the internal portions of the at least first hand forming the interna! connective cavity being made from a self lubricating plastics material.

Preferably the bearing drive shaft is molded with internal cavities.

In a further aspect of the invention there is provided a door knob or handle comprising: a plurality of body parts, at least one of said body parts being molded from two sides and having ian internal structure connectable with a drive shaft for retracting a latch to allow a door to be opened; at least one intermediate means for locating between the body parts, said body parts and respective intermediate means having at least complementary abutting surfaces near their external edges; and connecting means for connecting the body parts and the Intermediate means such that when the body parts and the intermediate means are connected the internal structure is not accessible except through the opening of for the drive shaft.

Preferably the Intermediate means includes locating means for aiding locating of the body parts such that the outer edges of said body parts are substantially aligned but spaced from each other.

Preferably the intermediate means has an outer edge which extends over the outer edges of the abutting body parts. * £' , Preferably the door knob comprises only two main body-parts which0- ~S"OVl99r together with the intermediate means form the external surface of the door knob, one of said body parts having said internal structure and the other of said body parts being a closing gap.

Preferably the two body parts have planar circular outer edges and the intermediate means comprises a ring or disc.

Preferably the connecting means comprises clips that clip the internal surfaces of the body parts to the intermediate means.

Preferably the intermediate means and the body parts are welded together.

In order that the invention is more readily understood a particular embodiment thereof will now be described by way of example oniy with reference to the accompanying drawings wherein: BRIEF DESCRIPTION OF DRAWINGS Figure 1 is an elevational sectional view along section line 1-1 of a latch tongue mechanism in accordance with the invention; Figure 2 is an elevational sectional view along section line 2-2 of a latch tongue assembly in accordance with the Invention; Figure 3 is an end sectional view along section line 3-3 of the latch -tongue operating mechanism; Figure 4 is an assembled part sectional view of a door handle assembly for the latch tongue mechanism in accordance with the invention; Figures 5, 5a, 6 and 6a are elevational views of a handle lock and drive shaft; Figures 7 and 7a are elevational views of an escutcheon plate lock in accordance with the invention; Figure 8 is an exploded view of one side of a door handle and latch drive assembly; Figure 9 is an exploded view of the latch drive and latch mechanism including the casing; and 30 Figures 10A to 10D are assembly drawings of the latch tongue mechanism.

DETAILED DESCRIPTION OF DRAWINGS 0 1 J1 8 Referring to Figures 1, 3 and 9 a preferred embodiment of the invention comprising a latch mechanism is shown. The latch mechanism comprises a latch casing 10 a carriage means 30, a latch tongue 50 and a cam drive 70. The latch mechanism also includes two springs, the main spring 41 and the 5 latch tongue spring 61. The latch casing 10 is the main casing of the latch mechanism and comprises a body section 11 which has a rear surface 16 a front rim 17 and an opening 18. The body section 11 and the rear surface 16 is configured to house the carriage means 30 and the main spring 41 such that parts of the carriage means can extend out through openings in the rear surface 10 16 but so that the main spring is unable to extend past the rear surface but is held within the main section 11 of the latch casing. The front rim 17 of the latch casing 10 can have a quality commercial finish so that it may be the portion of the latch mechanism that is visible when inserted into a door in place of the present style of latch mechanisms. Alternatively a cover plate or other facade 15 may completely hide the latch mechanism from sight.

The latch casing 10 includes an extended rear section 12 of the main body and a separate latch casing body side section 13. The rear section 12 and the separate side sections 13 are configured to complement each other and to preferably fall within the sizing of the main body 11. In this way only a single 20 sized hole Is needed within the door frame. Both the rear section 12 and the side section 13 include holes 14,15 which align when the sections are properly located next to each other. The aligned holes allow for the mechanism such as a drive shaft of the opening means to be inserted. This will be discussed in detail in another section.

The carriage means 30 of the latch mechanism is formed from a body section 31 and extended arms 32. The carriage means body section includes front bearing rings 35, opening 37 and body receiver posts 36. The extended arms 32 include arm posts 34. The latch tongue 50 includes a latch tongue protrusion and a plurality of mounting arms 52. The arms 52 are adapted to 30 closely enclose the spring 61 to capture and retain the spring so that the ^ compressive force of the spring is substantially aligned with the direction of j movement of the latch tongue 50. Furthermore the arms 52 of the latch tongue • ^ /> . ft V V ^ • 9 50 are adapted to fit neatly within the large spring 41 to prevent escape of the arms 52 from the receiver posts 36 by restricting outward movement of the arms 52,fromJheir constrained position.jThe mounting arms including fixing points 53. The cam drive 70 includes a cam drive locating means 71 and a cam drive 5 body 72 having a curved driving surface 73.

In operation the cam drive 70 is positioned within the latch casing body extended section 12 and the separate side section 13 such that the cam drive locating means 71 aligns with the aperture 14 of the latch casing sections. A drive shaft (not shown) of an operating means is fitted into and engaged with the 10 cam drive locating means. The cam drive is able to rotate to a certain degree within the properly located extended section 12 and side section 13. These two sections can be maintained in position by screw, or other fixing means such as spring clips 18 engaging in apertures 19; or to be held together due to the construction of the operating means maintaining the two sections together. The 15 cam drive curved driving surface 73 effects movement of the carriage means 30 by contact with the arm posts 34 of the carriage means 30. When the carriage means is in position, the body 31 of the carriage means i9 looated in the main body 11 of the latch casing 10 and the arms 32 of the carriage means extend Into the extended section of the latch casing body with the drive rods 33 located 20 within the groove of 74 of the body of the cam drive 70 and the arms posts 34 being on the other side of the drive shaft of the operating means from the main section 11 of the latch casing. Thereby rotation of the drive shaft of the operating means, rotates the cam drive 70 and effects movement of carriage means 30 along the length of the casing means 10. The carriage means 30 25 includes body 17 and extended arms 32 which are m<wed by rotation of the driving surface 73 which carries with it the latch tongue 50 captured at post 36.

Thus the body 17 reciprocates In response to the cam drive 70 to move in piston like manner in the casing 10. Body 17 forms a large f-uttaca area against which spring 41 abuts under compression in assembly. The particular curve or 30 combination of curves forming the curved driving surface 73 of the cam drive in combination with the partiwlar shape of the arm posts 34 of the latch .carriage^ ' means can be altered tr ofrsct particular rates of movement or varyin^rates of 15Novm$$ movement of the carriage means in relation to the rate of rotation of the drive shaft of the operating means. One preferred configuration is to have a single curvilinear, curved driving surface 73 together with angled symmetrically opposite arm posts 34 on respective extended arms 32 such that the curved 5 driving surface encounters one of said arm posts 34, depending on the direction of rotation of the cam drive, at the furthest point from the axis of rotation of the drive shaft of the operating means. As the cam drive rotates further the curved driving surface remains in driving contact moves along with the arm post but with a continuously differing position on the arm posts. Thereby the rate of 1 o movement of the carriage means relative to the rate of rotation of the handle can be altered by altering the angle of the arm posts 34 relative to the direction perpendicular to the direction of travel of the carriage means and/or by altering the curve of the curved driving surface 73 of the cam drive 70.

The movement of the carriage means by the cam drive is directly related 15 to the movement of the latch tongue 50 and thereby the retraction of the latch tongue. This mechanism will be discussed later in greater detail. The return of the carriage means to its starting position so that the front surface of the front bearing rings 35 aligns with the front rim 17 of the latch casing and the latch tongue protrudes is effected by the spring 41 which is located around the 20 carriage means but within the main body 11 of the latch casing. The spring 41 at one end contacts the rear of the bearing rings 35 and at the other end contacts the rear surface 16 of the main body of the latch casing. Thereby when the cam drive effects movement of carriage means towards the rear of the latch casing the spring 41 is contracted. Upon release of the drive shaft of the 25 operating means then the spring resiliently returns the carriage means towards the starting position. The reverse side 75 of the cam drive contacts the arm posts 34 of the carriage means and restricts further movement of the carriage means out of the latch casing.

LATCH MECHANISM ASSEMBLY 30 With reference to Figures 10A to 10D the latch tongue 50 is attached to the carriage means by a combination of mounting arms 52 with fixing pdirits ' and the small spring 61. The latch tongue has a plurality of mounting^arms and o< nunnuiu i ii iu li 0 127 11 the spring is located within these mounting arms. The fixing points 53 connect with the rear surface of the receiver posts 36. The latch tongue thereby retains its position by the action of the spring acting between the front surface of the receiver posts 36 and the latch tongue and the mounting arms with fixing points 5 restricting the extent that the latch tongue can move away from the receiver posts 36.

The assembly of the latch is effected by first inserting the latch tongue spring 41 within the latch tongue 50 and fixing the latch tongue to the carriage means 30 by clipping the bayonet style mounting arms with their fixing points in 10 and around the receiver posts 36 after passing through the front opening 37 of the carriage means. The carriage means spring 41 is then affixed to the carriage means by passing the spring over the extended arms 32 including the drive rods 33 until it contacts the bearing rings 35. The two way cam drive 70 is then inserted between the drive rods 33 such that they are positioned in the 15 groove 74 and ahead of the arm posts 34. The curved surface 73 of the cam drive 70 may have a flattened portion so as to decrease the distance required between the extended arms 32 so as to facilitate insertion of this assembly into the casing. The cam drive 70 includes a pair of spaced apart lobes 72 with the arm posts 34 of the carriage 30 extending between the lobes as best shown in 20 Figure 9 forming a T bar drive behind the cam lobes thereby providing greater strength in the moldable arm posts 34 and the cam drive. During assembly of the components the cam drive 70 can conveniently be preloaded onto the arm posts 34 as shown in Figure 10D. It will be understood that the component assembly can be conveniently performed by automatic machinery with the 25 various components being assembled in a single direction as shown in Figures 10A to 10D. When this assembly Is almost fully installed the carriage spring compresses against the shoulder or other restraining means at the rear 16 of the main body 11 of th© carriage means. The assembly is then retained in the latch casing by inserting the drive shaft of the operating means through the 30 locating means, 71 and the holes 14 and 15 of the latch casing.

It is an important feature of this invention that the preferred material for manufacturing the majority of the parts of this latch mechanism is plastics. Thec~. • ' ■> * 2 5 0 12 12 particular advantages of using plastic is that intricate parts can be easily and precisely molded. In operation a latch made from plastics operates without lubrication and the material allows for flexibility, in working of the mounting arms 52. Whilst assembling the latch mechanism the latch tongue mounting arms 52 5 flexibly distort around the receiver posts 36 but with enough resilience to snap back into position around the receiver posts and contact the rear surface thereof. The particular structure of this latch mechanism also makes the latch suitable to be made from plastics. The dual springs minimize the bearing load on the parts and thereby in particular the spring 61 can be less resilient than the 1 o main spring 41 such that the closing of a door can be gentle and very little of the force of closing a door is relayed to the carriage means cam drive or operating means of the closing means. It will be appreciated that molding of the various components from strong moldabie plastics material is possible giving rise to ease of manufacture and assembly of the components despite having intricate 15 configuration.

Referring to Figures 4 and 8, there is shown a preferred form of the opening means comprising a drive means 110, a pair of fixing plates 120, connecting means 130, escutoheon plates 140 and handles 150.

The drive means 110 includes a bearing drive shaft 113 which 20 complements the cam drive aperture 71 in the cam drive 70 thereby rotation of the cam drive is effected upon rotatipn of the drive shaft. Since this shaft is the main bearing element it is essential that it is made from high strength material. A preferred material is moldingirom polycarbonate as this provides the strength but allows a decrease in the mass required. This will be discussed in further 25 detail. The drive means 100 also includes at least at one end of the drive shaft a pair of extending spaced flexible arms 111. A shoulder 114 separates the flexible arms from the major driving portion of the drive shaft 113. The flexible armaNlljl wso include protrusions or wedges for one way insertion into the connecting means 130.

The connecting means 130 Includes an internal receiving cavity 1^6 for receiving the flexible arms 111 of the drive shaft 110, and the -second connecting means includes an internal cavity 132 which allows for direct fitting ^ ■:jN°vI993SJ 0 1 13 to the drive shaft 113. The connecting means 130 also includes extending flexible arms 134 with releasing protrusions 135 and abutment end 133.

As shown in Figures 4 and 8 the door handle 150 includes an internal cavity with an opening 151 formed by edges 152 and having a rear surface 153.

In assembly the respective connecting means 130, escutcheon plates 140 and handles 150 are connected and held together in two assemblies. The connecting means 130 fits within the hole of the escutcheon plate 140 and the abutment end 133 is preferably sized to restrict the connecting means from passing completely through the escutcheon plate. The extending flexible arms 10 134 of the connecting means are then inserted into the opening 151 of the handles thereby deforming the arms by flexing them together. Upon full insertion past the edges 152 of the internal cavity of the handles, the natural resilience of the flexible arms allows them to return to their usual position and the locking protrusions 135 coact with the rear surfaces 153 to hold the 15 connecting means fixed to the handles, thereby turning of the handles directly turns the connecting means. Preferably the internal edges 152 form a square shape and the extended arms are planar and able to provide large contact with the edges. Also it is preferred that the internal portions at least of the handle and the connecting means are made from a lubricating type of material and 20 particularly a self lubricating plastic such as nylon. Such material is needed to cope with the torsional stresses and strains resultant from the handle driving the connecting means to drive the drive shaft and latch means.

■""" The abutment end or flange 133 and annular protrusion 133a interengages with the internal surface of the escutcheon plate 140 to form a 25 reinforcement against lateral forces applied to the door handle 150. 1 The next stage of assembly is to affix the fixing plates 120 by means of screw or otherwise to the door or to each other when located on either side of the door. The control hole 121 is sized to allow the drive shaft 113 and the shoulder 114 to pass through. The flexible arms 111 and protrusions 112 are 30 locked into the internal cavity 136 of the connecting means 137 in a similar manner to the connection between the connecting means and the hahdie^. ' Generally the opening means is sold in a partly preassembled form..: As shown 250727 14 in Figure 3 one part of the assembly will comprise a door knob 150 attached to the escutcheon plate MO, connecting means 130, and the flexible arms 111 and protrusions 112 at the end of the drive shaft 110. The other part assembly Includes the other door knob 150, escutcheon plate 140 and other connecting 5 means 131; with these two subassemblies together with a pair of fixing plates 120, the door latch may be finally assembled by attaching the fixing plates 120 to either side of the door or otherwise locating them in position. The ^scutcheon plate 140 Is then eorewed onto the fixing plates 120 by the partial thread 143 consisting of one or more extended flanges coacting with the fixing portions 123 10 of the fixing means. The fixing portions 123 or the extended flanges 143 are angled such that rotation of the escutcheon plate 140 provides a tighter fit. Locking grooves or notches 144 may also be incorporated.

The other side of the drive shaft 113 which does not include attachment means is so configured to allow a floating attachment of the drive shaft to the 15 connecting means 131. The sub assembly of the handle, escutcheon plate and connecting means is held in place by attachment as above to the fixing means 120. However the internal cavity 132 of the connection means 131 is extended and the drive shaft 113 extends a distance into the internal cavity 132 dependent on the thickness of the door and fitting of all of the elements of the 20 opening means. The drive shaft 113 however fits in the internal cavity such that rotation of the handle causes rotation of the drive shaft.

Q As shown in Figure 8, the drive shaft 113 when molded can be formed with apertures therealong to save material but maintain strength and flexibility.

This structure is not viable with use of metals and therefore a large cost saving 25 is effected by use of moldable plastics material. Also as shown in Figure 8 the drive means may be molded to provide better attachment points to the connecting parts by accentuating some of the edges of the drive shaft. The apertured drive shaft exhibits torsional flexibility to absorb higher than usual turning forces imparted to it without damage to the latch mechanism, but to warn 30 the user of impending damage if the force is increased.

In order to be able to make the complex internal structure of the handle or7 door knob 150 and to limit the amount of material required to make the door ^^/99j ° -5 j h t i* V /' 0 1 knob it is usually necessary to be able to mold from two opposed directions. To facilitate this and to form an internal cavity and it is required that the knob 150 comprise at least two body parts and be substantially hollow. As shown in Figure 4 the handle 150 is comprises of two body parts 155 and 156. The first 5 body part 155 is a cap to provide an external covering to the door knob that is presentable and stylish. The second body part includes an internal structure having a bore 152 and the rear surfaces 153 as shown in Figure 4 so as to hold connecting means 131 fixed to the handles, thereby effecting turning of the drive shaft when the door knobs are turned. It is difficult in practice for the two body 10 parts to be directly joined together, as it is difficult to accurately align the body parts and usually the joining edges do not meet in a smooth quality finish. To overcome this problem it is therefore also necessary to include an intermediate joining member 157 which can be in the form of a ring or solid disc such that the edges of the body parts 155,156 abut the ring or solid disc 157 and are 15 connected together to form a completed handle. It Is therefore necessary that the body parts and intermediate member have complementary surfaces so that a close abutment of these parts of the handle is possibis, To facilitate alignment the intermediate member or the body parts may have integral locating means such as projections or flanges 158.

To connect the two body parts and the intermediate member together there may be provided clips (not shown) made integral with the internal surface of the body parts of separately attached to the body parts. These clips deflect before passing through holes in the ring or disc 157 and the natural resilience of the material brings it back to the undetected position and does not allow for 25 release back through the holes due to protrusions connecting with the plate or disc. Alternatively and preferably the body parts and intermediate member may be welded together or adhesively bonded such as with glue.

The ring or disc 157 may also include overhanging external edges (not shown) such that the join between a body part and the intermediate member Is 30 hidden behind the overhang. Other external designs may also be used on the intermediate member such as a particular colour or pattern to distinguish'these^ goods from others. 0 1 2 16 Whilst one particular embodiment of the invention has been described herein it will be understood to persons skilled in the art that modifications may be readily effected without departing from the spirit and scope of the invention. 3'*r c 'V ;-\v *t\\\ v</ / 250127

Claims (13)

WHAT WE CLAIM IS:

1. A latch assembly for retaining a door closed, comprising: a carriage means for mounting in the door and operable by an opening means for facilitating opening of the door; connecting means connecting said carriage means with said opening means; and a latch tongue resiliently mounted to said carriage means; . wherein said mounting of said latch tongue to said carriage means results in the latch tongue moving with the carriage means when movement of the carriage means is effected by said opening means, said latch tongue being adapted to resiliently move relative to the carriage means upon closing of the door, and the carriage means is slidably and resiliently mounted for movement in casing means such that the carriage means extends substantially in the same alignment as the latch tongue and wherein said resilient mounting of said carriage means urges the carriage means to move relative to the casing means and in the opposite direction to the direction of the movement of said carriage means effected by said opening means.

2. A latch assembly as claimed in Claim 1, wherein the resilient mounting of the carriage means to the casing means comprises a spring, said spring being located around at least a portion of the carriage means and within said casing means such that the spring acts between a surface of the carriage means and an internal surface of the casing means.

3. A latch assembly as claimed in Claim 1, wherein the latch tongue includes resilient arms forming said casing means, the casing means being adapted to house a latch tongue spring controlling movement of the latch tongue independently of the carriage means. 250127

4. A latch assembly as claimed in Claim 3, wherein said carriage means includes two extending arms, at least one of said arms having a post extending at an angle to said one arm; said connecting means comprising a cam drive having central means for connection to said opening means such that the opening means is able to rotate said cam drive, said cam drive further including parallel spaced curved lobe body portions for locating said cam drive to said carriage means; such that the extending arms of the carriage means fit between the spaced body portions of the cam drive but on opposite sides of the central means of the cam drive; wherein said rotation of said cam drive by said opening means in one direction effects contact of at least one of said curved lobe body portions with a said post and forces the carriage means to move in opposition to the resilient mounting of the carriage means to the casing means.

5. A latch assembly as claimed in Claim 4, wherein the carriage means and the resilient arms of the latch tongue are interlockably engaged to form a housing constraining said latch tongue spring.

6. A latch assembly as claimed in Claim 5, wherein the post of the arm of said carriage means and the curved lobe body portions of the cam drive are shaped and/or angled to provide a non-linear amount of rotation of the cam drive relative to the amount of movement of said carriage means.

7. A latch assembly as claimed in Claim 6, wherein the arms of the carriage means are of resilient material to allow flexing of the arms during assembly of the carriage means and the casing means to allow partial pre-assembly of the latch components.

8. A latch assembly as claimed in Claim 4, wherein the curved lobe portions of said cam drive are preloaded onto said extending arms prior tojitting of the carriage into said casing means. 250127

9. A latch assembly as claimed in Claim 8, wherein the carriage means, latch tongue means, latch and carriage springs are preassembled with the latch tongue and associated spring constrained within the carriage body and loaded from one end thereof, said carriage spring being contained on the carriage body.

10. i A combination of latch assembly as claimed in any one of the preceding claims and a handle means to retract a latch tongue that protrudes from the extremities of a door, the handle means comprising: a bearing drive shaft shaped to complement a receiving bearing surface of the latch mechanism whereby rotation of the bearing drive shaft retracts the latch tongue; a set of door handles effecting rotation of the bearing drive shaft, at least a first of said handles having an internal connecting cavity; and connecting means for connecting at least one end of the drive shaft to the first handle; said connecting means comprising at l^ast one flexible locking means; whereby the internal connecting cavity of the at least first handle is configured to receive and lockably retain the flexible locking means, the locking means being retained within said door handle cavity by flexing when being inserted in a flexed state and the cavity being shaped such that when the locking means is fully inserted the locking means is able to substantially and resiliently return to its unflexed state and shape of the cavity restricts the locking means from being withdrawn from the handle.

11. The combination as claimed in Claim 10, wherein the bearing drive shaft includes at least one integral attachment means for attaching to said connecting means, said attachment means comprising flexible arms for resilient insertion and locking in an internal cavity of said connecting means. 250127 xo

•12. The combination as claimed in Claim 11, when dependent upon any claim dependent upon claim 4, wherein a cam drive aperture is provided in the cam drive and is configured to ailow relatively wide tolerance fit of the drive shaft therein.

13. A latch assembly for retaining a door closed constructed and arranged substantially as herein described with reference to, and as illustrated in, Figures 1-4, 5, 5A, 6, 6A, 7, 7A, 8, 9, 10A, 10B, 10C, and 10D of the accompanying drawings. HAINES TECHNOLOGY PTY LTD By Their Attorneys