AU771240B2 - Lock for double hung sash window - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT US C OrFIC Applicant(s): "h,4 W A. 004 47 898 Invention Title:

TR

LOCK FOR DOUBLE HUNG SASH WINDOW L SE r r The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 LOCK FOR DOUBLE HUNG SASH WINDOW FIELD OF THE INVENTION This invention relates to a lock for a double hung sash window and relates particularly but not exclusively to a lock for a double hung sash window which is fabricated from aluminium or like extrusions.

DESCRIPTION OF PRIOR ART Hitherto, double hung sash windows have been known and locks have been provided for locking the two sashes in a closed condition. Typically, there is a latch or locking mechanism fitted on one sash which swings to cooperate with another part of the lock or latching mechanism carried by the other sash. Typically, the locking is effected centrally of the top rail of the inner sash with the bottom rail of the outer sash midway of the window opening. In other words, when the top rail on one sash is aligned with the bottom rail of the other sash window is fully closed then the locking can be fully effected.

Reference is now made to our co-pending Australian patent application no. 56100/96 which relates to an improved lock. The description in that specification is to be imported herein by reference.

Reference is also made to Australian patent application no. 39904/93 by J N Putland which relates to a different improved lock.

OBJECT AND STATEMENT OF THE INVENTION It is an object of the present invention to provide an alternative form of lock for a double hung sash window which in at least some preferred embodiments is superior to the lock arrangement in the aforementioned Australian i patent applications.

o\ 35 Therefore according to a first broad aspect of the present invention there is provided a lock for a double hung sliding sash window for permitting locking of one sash o•* \\melb_files\home$\joannem\keep\47496-99 Crane.doc 23/01/04 3 relative to the other so that the sashes can no longer be opened or closed relative to one another, said lock having a locking tongue member to be carried by a frame part of one of the sashes for movement into a tongue receiving opening carried by the other sash, said locking tongue member being moveable by rotational operation of a handle rotatably mounted to one of the sashes said handle being drive connected with a push rod to move said push rod to extend or retract said push rod relative to said handle in a direction parallel to a plane of said one of the sashes, said push rod co-operating with said locking tongue member to cause said locking tongue member to move in a direction transverse to the direction of movement of the push rod so said tongue member will move into or out of said tongue receiving opening as said push rod is so moved.

Preferably the extension of said push rod causes said locking tongue member to move into said tongue receiving opening.

Preferably there are two locking tongue members, one on each side of said one of the sashes and wherein there are respective tongue receiving openings on each side of the other of the sashes.

Preferably both of said locking tongue members 25 are moveable by respective push rods operated from a single o o common handle.

Preferably said handle carries a pinion gear which is rotated as said handle is rotated and wherein said gear is drive engaged with a rack gear connected with said push rod.

Preferably each of said push rods is connected 0:0" with a respective rack and is rack drive engaged with said pinion gear.

Preferably said tongue is mounted within a body 35 for movement in a direction transverse to the plane of said one of the sashes.

Preferably said tongue has a cam surface which is \\melb_files\home$\joamem\keep\47496-99 Crane.doc 23/01/04 3a engaged by a corresponding cam surface carried at a free end of said push rod and the extension of said push rod \\melb files\home$\joanem\keeP\47496-99 Cranedoc 23/01/04 4 causes both cam surfaces to engage to cause said tongue to move out of said tongue receiving opening.

Preferably said tongue is biased by spring means to extend into said tongue receiving opening so that when said push rod is retreated said tongue will extend under the influence of said bias into said tongue receiving opening.

Preferably said body carries a swingable arm, said swingable arm has a track locating pin means thereon, said pin means being able to extend or retract to engage in a slot in a track of a window frame of the double hung sash window, said pin means serving to guide said one sash for sliding movement relative to said track when extended, and when retracted permitting said one sash to be moved generally perpendicularly to the plane of the window.

Preferably said arm carries pressing means for pressing on said track when said pin means is retracted whereby to move said track away from said one sash and to permit said one sash to be moved in a direction generally perpendicular to the plane of the window.

Preferably, said window frame has a generally "U" shaped transverse cross section jamb part which extends the height of the sash at one side of the sash, the having its open ends directed towards said sash, there being a jamb liner received in said shaped jamb part, said jamb liner also extending the height of the sash and able to advance or retreat in said jamb part towards or away from said sash, spring biasing means between said jamb part and said jamb insert biasing said jamb insert towards said 30 sash, said jamb liner carrying sash engaging surface means for engaging with a side edge of said sash.

Preferably said sash engaging surfaces are "V" shaped in transverse cross section and engage with oo 0 0 oo\ \\melbfiles\home$\Priyanka\Keep\speci\47496-99.doc 22/12/03 5 complimentary shape transverse cross section edge surfaces at said side edge of said sash, whereby to locate said sash relative to said jamb liner, permits said sash to slide up and down relative to said jamb liner, and to inhibit against movement of said sash in a direction perpendicular to the plane of said sash.

Preferably said jamb insert is able to retreat in said jamb part so as to enable said sash to move in a direction perpendicular from the plane of said sash.

Preferably said sash carries pressing means for pressing against said jamb insert to cause said jamb insert to retreat in said jamb part to permit said sash to move in a direction perpendicular from the plane of said sash.

Preferably the lock as described above as a first part of this invention is fitted to said sash window of the sash window of the invention referred to herein.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention can be more clearly ascertained reference will now be made to the accompanying drawings wherein: Figure 1 is a front elevational view of one example of a preferred embodiment; Figure 2 is a close up view showing the top part of one of the sashes; Figure 3 is a perspective view similar to that of Figure 2 and showing only part of the top of the sash; Figure 4 is rear perspective view showing components of the lock; Figure 5 is a plan view which diagrammatically shows operation of push rods and locking pins; Figure 6 is a perspective view similar to that of Figure 3 but showing the locking mechanism displaced from the sash and locking pins for co-operation into opening in the other sash; Figure 7 is an exploded perspective view showing components of the push rods and locking pin; H:\Ga I e\Keep\speci\cAP. PP5924. Boral. Lock. doc 9/09/99 6 Figure 8 is a front elevational view of a swingable arm and pin means used for locating in a track of the outer peripheral frame of the window and for pressing against the outer peripheral frame when the swingable arm is rotated; Figure 9 is an isometric view of the outer peripheral frame showing how the sash frame engages therewith; Figure 10 is a transverse cross sectional view at one side of the outer peripheral frame showing the relationship of the outer peripheral frame with two sash window frames; Figure 11 is a side elevational view of a spring means used in the outer peripheral frame; Figure 12 is a perspective view of the spring means shown in Figure 11, and Figure 13 is an isometric view of a bottom corner of the lower part of the sash 9 showing pivot pin means.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring firstly to Figure 1 it can be seen that there is a window having an outer peripheral frame 1 typically of aluminium extrusion. Mounted within the outer peripheral frame 1 are a pair of sash windows 3 and Sash window 3 has its own sash frame 7 of aluminium extrusion, and sash window 5 has its own sash frame 9 of aluminium extrusion. The sash window 5 is provided for up and down sliding movement relative to sash window 3 by sliding in tracks provided in the vertical outer peripheral 30 frame 1. When sash window 3 and sash window 5 are in the o*o position shown in Figure 1, the sash windows 3 and 5 can be locked relative to one another by operation of a handle 11 mounted midway at the top of the sash frame 9 of the window Figure 2 shows that the handle 11 can be rotated in an anti-clockwise direction to effect unlocking. A lock barrel is provided within the handle 11 to effect locking H:\Gale\Keep\speci\CAP.PP5924 .Boral .Lock.doc 9/09/99 7 of the handle 11 to, in turn, lock the sash windows 3 and together so that the whole window assembly cannot be opened without releasing the lock barrel and rotating the handle 11.

Figure 3 is a perspective view showing how the sash frame 9 and the sash frame 7 interlock when the top of the sash frame 9 is aligned with the bottom of the sash frame 11. In this case, the upper part of sash frame 9 is shaped with a downwardly extending flange 15, and the lower-most part of the sash frame 7 is shaped with a complimentary outstanding flange 17. The flanges 15 and 17 locate one behind the other when the windows 3 and 5 are in the fully closed position. This prevents lateral back and forth movement of one window relative to the other. The glazing has not been shown in Figure 3 to aid clarity.

Referring now to Figure 4 there is shown a rear view of the lock mechanism. It can be seen that the handle 11 is carried by a front housing 19. The housing 19 can, in turn, be fastened to the upper part of the sash window 9 as it includes two tubular internally screw threaded tubes 21 integrally formed therewith. Suitable apertures are provided in the face of the upper part of the sash frame 9 to allow the tubes 21 to pass therethrough. Screws (not shown), can be inserted from the opposite side of the upper part of the sash frame 9 into the screw threaded tubes 21 to thereby fasten the housing 19 to the face of the upper part of the sash frame 9 as generally shown by the mounting positions shown in Figures 1, 2 and 3. A further opening is provided in the upper part of the sash frame 9 to allow a pinion gear 23 to also pass into the body of the upper part of the sash frame 9. The pinion gear 23 is mounted on an axle which is supported in the housing 19 and connects with the handle 11 through the lock barrel 13 for rotation.

The pinion gear 21 has rectangular block shape rack gears 25 and 27 associated therewith. The rack gears 25 and 27 have a transverse rectangular dimension which enables sliding fitting within the hollow body of the upper sash H:\Cale\Keep\speci\CAP.PP5924 Bora1.Lock.doc 9/09/99 8 frame 9. The rectangular hollow section of the upper part of the sash frame 9 can be seen in Figure 3 by the rectangular hollow body part 29. Each of the rack gears and 27 has an elongate slot 31 through which the tubes 21 pass. Accordingly, as the handle 11 is rotated, the pinion gear 23 is rotated which, in turn, drives the rack gears and 27 so that they extend or retract. The rack gears and 27 are, in turn, connected with push rods 33 which, in turn, co-operate with locking tongue members 35. Only one of the locking tongue members 35 is shown in Figure 4 being the left hand side. A similar locking tongue 35 is provided at the right hand side. As the push rods 33 extend, the locking tongue members 35 are caused to be retracted so that they can withdraw from a tongue receiving opening 36 in the opposite window sash.

Figure 6 shows that at one side of the sash frame 7 there are provided three tongue receiving openings 36 provided on a plate 37 which is, in turn, attached to the sash frame 7. Attachment can be by any convenient means to provide suitable locking of the sash windows 7 and 9 relative to one another..,- A similar plate 37 with corresponding tongue receiving openings 36 is provided on S•the other side of the sash window 7 The push rods 33 are held captive relate to the :o ~25 rack gears 25 and 27 by screw means which pass through screw openings 39.

Figure 5 diagrammatically shows how the push rods ~35 can be extended or retracted. Here it can be seen that a cam surface in the form of a block shaped cam 39 with a 30 ramp surface 41 moves with the push rods 33 in a direction o* transverse to the plane of the sashes 3 and 5. The ramp surface 41 engages with a corresponding ramp surface 43 formed integrally with the tongue 35. The tongue 35 has a rectangular main body part 43 which is suitably housed within a block 45 which is attached at the side edge of the sash frame 9 as will be described hereinafter. The block therefore provides a housing for the block 43 and also H:\Gale\Keep\speci\CAP.pp5924.Boral .Lock. doc 9/09/99 9 for the cam surface 39. Spring means 47 is mounted within the block 45 to urge the tongue 35 outwardly from the sash frame 9 and into a tongue receiving opening 36. Thus, when the push rods 33 are retracted by operation of the handle 11, the spring means 47 pushes the tongues 35 into the corresponding tongue receiving openings 36 at each side of the sash frame 9. When the push rods 33 are extended the ramp surfaces 41 engage with the blocks 43 on their ramp surface and causes retraction of the tongues 35. This, in turn, releases locking of the sash windows relative to one another. It can therefore be seen that the tongues 35 move in a direction transverse to the plane of the sashes resultant from a corresponding movement of the push rods 33 in a direction parallel with the plane of each of the sashes and windows. This, in turn, is effected by rotation of the handle 11. It can also be seen that the ramp surfaces or cam surfaces when engaged cause the tongues to move out of the tongue receiving openings 36. It can also be seen that the tongues 35 are biased by the spring means 47 to extend into the tongue receiving openings 36 when the push rods 33 are retracted and so the tongues will extend under the influence of the bias of the spring o means 47 into the tongue receiving openings 36. It should be appreciated that the push rods 33 move within the hollow body 29 of the sash frame 9 and that part of the block is also mounted within the hollow body of 29 of the sash frame 9.

Figure 7 shows an exploded perspective view of the cam surface block 39, block 35 and block 43 carrying the tongue ~The block 45 has a rectangular transverse cross sectional shaped body part 49 which neatly fits within the hollow body 29 of the sash frame 9. It also has an upper part 51 with an undercut slot or space 53. In other words, the upper part 51 overhangs the body part 49 and there is a space 53 therebetween.

Figure 3 shows an elongate slot 55 in the top H:\Ga e\Keep\speci\CAP.PP5924. Boral. Lock.doc 9/09/99 10 surface of the upper part of the sash 9 and this slot enables a screw to pass through a screw opening 57 in the upper part 51 and into the body part 49. When the screw is tightened, it clamps the block 49 at the end of the upper part of the sash 9. The upper part 51 is then mounted at the top of the upper part of the sash frame 9 as also shown in Figure 3.

Referring now to Figures 9 and 10 it can be seen that the outer peripheral frame 1 has three individual aluminium extrusions. A first extrusion comprises a standard window frame 63 which has a depending leg 65 for permitting structural mounting to a building. The second extrusion is a generally shaped extrusion 67 which is fitted to the standard frame 63 and is dimensioned so that it nestles therein. The free ends of each of the arms of the shaped extrusion 67 have inwardly directed tongues 69. The third extension, which is mounted within the "U" shaped extrusion 67 is a jamb liner 71. The jamb liner 71 has a generally shaped configuration in transverse cross section which provides two internal cavities 73 and in the jamb liner 71. The transverse width of the jamb liner 71 is such that it can be neatly received between the tongues 69. Ribs 77 provided on the jamb liner 71 prevent the jamb liner 71 from being displaced laterally outwardly of the shaped extrusion 67. The jamb liner 51 can be fitted within the shaped extrusion 67 by sliding longitudinally therein. The jamb liner 71 can therefore move to advance or retreat within the shaped extrusion "0 67 except that it is limited in its advancing by the engagement of the tongue 69 with the rib 77.

Spring means 79 shown in Figures 11 and 12, in the form of leaf springs, are fitted to the top and bottom 0:0 of the jamb liner behind each cavity 73 and 75 as shown in Figure 10. The spring means 79 have a generally arcuate shaped body portion 81 and a return folded clip part 83.

The clip part 83 is provided to clip over the thickness of the metal in the jamb liner 71. Thus, the spring means 79 H:\Gale\Keep\speci\CAP.PP5924. Boral.Lock.doc 9/09/99 11 engages with the bottom surface 85 of the shaped extrusion 67 and urges the jamb liner 71 outwardly. The spring means 79 can be made of any suitable material.

Stainless steel is typically a suitable material.

Each of the cavities 73 and 75 of the jamb liner 67 have a pair of leading faces 87 and 89 which are inclined inwardly and define respective slots 91 and 93 therebetween. The sash frame 7 and 9 each carry a glide member 95 of a suitable plastics material which can be extruded. The glide member 95 can therefore be fitted to the sash frames 7 and 9 in a manner similar to that shown where the glide member 95 has slots 97 which engage with inwardly directed ribs 99 formed internally of the sash frame 7 and 9. The glide member 95 has correspondingly oppositely inclined faces to the faces 87, 89 of the jamb liner 71.

The inclined surfaces 87 and 89 define tracks and the corresponding surfaces of the glide members 95 locate the respective sash frame 7 and 9 relative to the outer peripheral frame 1 and permit the respective sashes 7 and 9 to slide upwardly and downwardly in the tracks in the outer peripheral frame 1. The U shaped extrusion 67 and the sash liner 71 are new components which fit to the existing 25 standard window frame section 63. The bias of the spring oo means 79 maintains the windows 7 and 9 located in the respective tracks formed by the respective incline surfaces 87, 89 at each of the cavities 73 and Figure 10 shows that sash 9 has a protruding finger 101 which locates in the slot 93 between the inclined leading faces 87 and 89 above cavity 75. The finger 101 therefore assists in retaining the sash window 9 relative to the outer peripheral frame 1. Returning now to Figure 2, 4 and 8 it can be seen that the finger 101 forms an integral part of the block 45. The block 45 carries a swingable arm 103 which has an axle 105 which passes through an upstanding rib 107 on the block 45 (see Figure H: \Ga le\Keep\speci\CAP.PP5924. Sora .Lock.doc 9/09/99 12 Each arm carries a pin 107 and the pin 107 is dimension with the same transverse dimensions as the finger 101. Thus, the pin 107 extends further into the slot 93 than the finger 101 when the arm 103 is swung to the vertically extending position as shown in Figures 2 and 3.

This further assists in maintaining the sash window 9 held relative to the outer peripheral frame 1 for its upwards and downwards sliding movement.

When the arm 103 is swung so that the free end moves inwardly of the outer peripheral frame 1, pressing means 109 forming part of the arm 103 engages with the jamb liner 71 and pushes the jamb liner 71 away from the sash 9 against the bias of the spring means 79. The jamb liner 71 tends to bow outwardly ie the region closest to the pressing means 109, extends further away from the sash 9 than the portions of the jamb liner 71 at the top and bottom of the frame i. This occurs because of the flexibility of the metal in the jamb liner 71. Thus, under such condition the top of sash 7 and the bottom of sash 9 may still be engaging with the jamb liner 71. Under such conditions, the sash window 9 can be swung downwardly from the outer peripheral frame 1 in a manner similar to that described in our aforementioned patent application 56100/96.

oo*.

Referring now to Figure 13 there is shown detail of pivot pin means 113 at a bottom corner of the sash frame 9 of sash window 5. A similar pivot means 113 is mounted on the opposite side of the sash window 5. The pivot pin means 113 is generally circular in transverse cross-section having a diameter which approximately equals the width of the slots 91 in the jamb liner 71. The vertical faces 115 are flattened to permit easy movement within the slots 91.

The pivot pin means 113 forms an integral part of an "Lshaped" block 117 which is shaped to fit in a sliding manner in the sash frame 9 as shown. The L-shaped block 117 therefore has an upstanding lug 119 and a main body 121. The main body 121 has the face which projects H:\Gal e\Keep\speci\CAP.PP5924. 8oral. Lock .doc 9/09/99 13 outwardly of the jamb frame 9 as the glide member Thus, the transition between the outer surface of the glide member 95 and the block 117 is smooth and continuous. This also assists in the location of the pivot pin means 113 between the slots 91. The block 117 is fastened to the sash frame 9 by a screw 123 which passes through the lug 119 and into the sash frame 9.

Thus, when the jamb liner 71 is moved away from the sash window 9 by operation of the pressing means 109, the pivot pin means 113 is still retained in the slots 91.

Under such conditions, the sash window 5 can be swung downwardly out of the outer peripheral frame 1 to permit cleaning.

It can therefore be seen that the sashes have engaging surfaces being the inclined surfaces to the leading faces 87 and 89 and that these are all complimentary V shaped in transverse cross section. Such permits the sash to be located relative to the jamb liner and inhibits movement of the sashes in a direction perpendicular to the plane of the sashes until such time as the arms 103 are rotated to cause the pressing means 109 to push the jamb liner 71 away from the sash window 9. The pressing means 109 effectively provides a cam arrangement which pushes the jamb liner 71 away from the sash window 25 109.

2 10 Modifications may be made to the above embodiment without departing from the ambit of the invention. The glide member 95, instead of being made from a plastic material may, in fact, be made from metal or other material. Typically, however, in order to facilitate easy •smooth gliding without undue binding, the glide member is made of a plastics material such as rigid PVC.

Other modifications may be made. For example, "instead of the U shaped extrusion 67 fitting to an existing standard window frame section 63, the U shaped extrusion 67 may be provided with a flange 65 similar to that of the standard section 63 to permit fastening to the structural H:\Ga e\Keep\speci\CAPPP5924 Boral .Lock.doc 9/09/99 14 part of the building in which the window is to be mounted.

It should be appreciated that with the above embodiment, the sashes are minimised for rattling because of the arrangement of spring biased mounting within the jamb liner 71. Further, operation of the arms 103 to effect downward swinging of the sash 9 is a relatively easy operation. The arrangement provides for smooth sliding of the sashes and enhance security over known sash window arrangements. Further, screws which fasten components in the sashes are not exposed. Additionally, the plastics material parts which are exposed to sunlight are maintained to a minimum. Further, standard spring balances can be used by locating within the hollow cavities 73 and Figure 10 shows a known spring balance 111.

Other modifications may be made to the invention as would be apparent to persons skilled in the art of production of windows. These and other modifications may be made without departing from the ambit of the invention the nature of which is to be determined from the aforegoing description.

C

.o.

H:\Gale\Keep\speci\CAP.PP5924.Boral Lock.doc 9/09/99

Claims (15)

1. A lock for a double hung sliding sash window for permitting locking of one sash relative to the other so that the sashes can no longer be opened or closed relative to one another, said lock having a locking tongue member to be carried by a frame part of one of the sashes for movement into a tongue receiving opening carried by the other sash, said locking tongue member being moveable by rotational operation of a handle rotatably mounted to one of the sashes said handle being drive connected with a push rod to move said push rod to extend or retract said push rod relative to said handle in a direction parallel to a plane of said one of the sashes, said push rod co-operating with said locking tongue member to cause said locking tongue member to move in a direction transverse to the direction of movement of the push rod so said tongue member will move into or out of said tongue receiving opening as said push rod is so moved.

2. A lock as claimed in claim 1 wherein a retraction movement of said push rod inwards from a side edge of said sash causes said locking tongue member to move into said tongue receiving opening.

3. A lock as claimed in claim 1 or claim 2 wherein 25 there are two locking tongue members, one on a left hand side and a right hand side respectively of said one of the 000 sashes, and wherein there are respective tongue receiving openings on each right and left hand side of the other of the sashes.

4. A lock as claimed in claim 3 wherein both of said locking tongue members are moveable by respective push rods operated from a single common handle. A lock as claimed in any one of the preceding claims wherein said handle carries a pinion gear which is rotated as said handle is rotated and wherein said gear is drive engaged with a rack gear connected with said push rod. \\melbfiles\home$\joannem\keep\47496-99 Crane.doc 23/01/04 15a

6. A lock as claimed in claim 4 wherein each of said push rods is connected with a respective rack and rack \melb-files\home\ joa~em\keep\ 47 496 -99 Cranedoc 23/01/04 16 drive engaged with said pinion gear.

7. A lock as claimed in claim 1 or claim 2 wherein said tongue is mounted within a body for movement in a direction transverse to the plane of said one of the sashes.

8. A lock as claimed in claim 7 wherein said tongue has a cam surface which is engaged by a corresponding cam surface carried at a free end of said push rod and the extension of said push rod causes both cam surfaces to engage to cause said tongue to move out of said tongue receiving opening.

9. A lock as claimed in claim 8 wherein said tongue is biased by spring means to extend in a direction into said tongue receiving opening so that when said push rod is retreated said tongue will extend under the influence of said bias into said tongue receiving opening. 1 A lock as claimed in claim 7 wherein said body carries a swingable arm, said swingable arm having a track locating pin means thereon, said pin means being able to extend or retract as said arm is swung to engage in a slot in a track of a window frame of the double hung sash window, said pin means serving to guide said one sash for sliding movement relative to said track when extended, and when retracted permitting said one sash to be moved generally perpendicularly to the plane of the window.

11. A lock as claimed in claim 10 wherein said arm carries pressing means for pressing on said track when said :i pin means is retracted whereby to move said track away from i said one sash and to permit said one sash to be moved in a 30 direction generally perpendicular to the plane of the window.

12. A lock as claimed in any one of the preceding claims fitted to. a double hung sliding sash window.

13. A lock as claimed in claim 12 wherein said sash o: 35 frame is made from hollow extruded material and at least •said push rod is mounted within a hollow part thereof. \elbfiles\home\Priyanka\Keep\speci\4 22/12/03 \\melb-files\home$\Priyanka\Keep\speci\47496-99.doc 22/12/03 17

14. A lock as claimed in claim 12 or claim 13 wherein said double hung sliding sash window is mounted within a window frame, said window frame being, in use, fittable within a window opening, said window frame having a generally shaped transverse cross section jamb part which extends the height of the sash at one side of the sash, the having its open ends directed towards said sash, there being a jamb liner received in said shaped jamb part, said jamb liner also extending the height of the sash and able to advance or retreat in said jamb part towards or away from said sash, spring biasing means between said jamb part and said jamb insert biasing said jamb liner towards said sash, said jamb liner carrying sash engaging surface means for engaging with a side edge of said sash. A lock as claimed in claim 14 wherein said sash engaging surfaces are shaped in transverse cross section and engage with complimentary shape transverse cross section edge surfaces of said sash, whereby to locate said sash relative to said jamb liner, to permit said sash to slide up and down relative to said jamb liner, and to inhibit against movement of said sash in a direction perpendicular to the plane of said sash.

16. A lock as claimed in claim 14 or claim 15 wherein 25 said jamb insert is able to retreat in said jamb part so as to enable said sash to move in a direction perpendicular to the plane of said sash.

17. A lock as claimed in claim 16 wherein said sash carries pressing means for pressing against said jamb 30 insert to cause said jamb insert to retreat in said jamb part to permit said sash to move in a direction perpendicular to the plane of said sash. *o **o \\meib files\hone$\Priyanka\Keep\speci\47496-99.doc 22/12/03 18

18. A lock for a double hung sash window as claimed in any one of the preceding claims, and substantially as herein described with reference to the accompanying drawings. Dated this 22 nd day of December 2003 DOWELL AUSTRALIA LIMITED By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia *o* \\melbfiles\home$\Priyanka\Keep\speci\47496-99.doc 22/12/03