AU625208B2 - Improved latch tongue - Google Patents

Description

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625208 COMMONWEALTH OF AUSTRALIA Patents Act 1952 WHITCO PTY. LTD. Name of Applicant(s): Address of Applicant(s): 450 Sherwood Road, SHERWOOD, QUEENSLAND 4075, AUSTRALIA t 0 0 o 00 0D 0 CO 0.

Actual Inventor(s): MR. GUNTHER SPREKELER of 62 Percy Street, TARRAGINDI, QUEENSLAND 4122, AUSTRALIA CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, Qld. 4000, Australia.

Address for Service: 0*06 0 0 00 00064 0 4r 041 *4 (I 4 COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: IMPROVED LATCH TONGUE The following statement is a full description of the invention including the best method of performing it known to us.

THIS INVENTION relates to an improved latch tongue for a lock.

In an earlier proposal there is disclosed a latch tongue for a lock for a security screen door. The tongue was provided with a series of teeth or serrations on a side face thereof which, in use, provided some degree of resistance to a lock fitted with such a tongue being forced. The serrations under such circumstances tended to engage an edge of an aperture in a striker mounted to a door frame.

In this earlier proposal the spacing or pitch of the serrations had a relationship to the thickness of the material of the striker and it was preferred that there be at least one l and one-half of a serration per thickness of the striker.

Thus, where a particular pitch for the serrations was chosen, that tongue was then only suitable for use with strike' off a particular thickness although the tongue could be used for S* ia a.l different strikers but not as effectively,

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Some locks, particularly security deadlocks do not employ strikers of relatively thin material against which the "2'6 latch tongue of the lock would locate but rather replaced the striker with a keeper. The keeper was either directly mounted to a frame adjacent the door to which the lock was fitted or was mounted to the frame by a separate mounting plate.

Keepers typically have a mounting portion through which A L g 3 fasteners may pass to fix the keeper to the frame and/or the mounting plate and a body portion. The body portion had a cavity with a tongue receiving aperture. The periphery of the aperture had a substantial width and serrated faced tongues were unsuitable for use with such keepers.

It is an object of the present invention to provide a latch tongue which at least minimises the disadvantage referred to above.

According to one aspect the invention provides a latch tongue for a lock, said latch tongue having a nose t tii portion, opposed side faces adjacent the nose portion and at least one deformable portion extending along one of said faces

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such that, in use, forcing of the lock causes a periphery of a tongue receiving aperture in a keeper to deform said portion to enable the tongue to resist forcing of the lock.

t t SThe deformtable portion may be a rib extending along .o a face of the tongue. Preferably the rib extends longitudinally of the face although it may extend transversely of the face if desired. If desired there may be more than one rib at spaced locations on the face. Preferably two spaced ribs are present. Where there are two ribs they are preferably located at or adjacent edges of the tongue.

The or each rib may be provided by either forming or providing a raised portion which extends beyond the plane of the face of the tongue. Alternatively the or each rib may l P s 4 be provided by forming a recess in the face where the or each rib is provided by an unrecessed area adjacent the recess.

It is preferred that one or more deformable portion be present on one face of the tongue although both faces may have one or more of such portions.

Where deformable portions are provided on both faces they may be ribs in the form of projections or ribs provided by forming recesses with narrow areas of material left remaining adjacent the recess as discussed above.

,1Q The nose portion has a keeper engaging face. This r tt S, face may be inclined and in which case the tongue is handed.

Alternatively the tongue need not be handed and the nose may w% be similarly contoured on both sides thereof to enable the tongue to be used for locks for right or left hand closing doors.

A particular preferred embodiment of the invention will now be described by way of example with reference to the drawings in which: Figure 1 is a perspective view of a lock incorporating a latch tongue according to an embodiment of the invention; Figure 2 is a fragmentary enlarged perspective view of a tongue according to an embodiment of the invention; Figure 3 is a perspective view of a keeper; and Figure 4 is fragmentary enlarged perspective view of the tongue with the deformable portions deformed.

i As shown in Figure 1, the lock 10 has a body 11, an operating knob 12, a major latch tongue 13 and a minor tongue 14. The operation of the lock 10 need not be discussed other than to say that with the lock either locked or deadlocked the tongue 13 projects from the body 11.

As shown in Figure 2, the tongue 13 has an inclined nose 15 and two opposed faces 16 (only one of w~ilch can be seen). Face 16 has a substantially rectangular recess 17 which defines two spaced, narrow deformable portions or ribs ~1Q 18, 19 which extend along the tongue and at edges of face 16.

These ribs can be deformed as is explained below.

Figure 3 shows a typical keeper 20. The keeper has a mounting portion 21 and a body portion 22. The keeper is normally fitted to a door frame so that face 23 is flush with the frame. A mounting plate 24 receivable by th'e keeper 4 14 facilitates fixing of the keeper to the frame.

The keeper body portion 22 has an aperture 25 for *:~~receiving the tongue. This aperture has a periphery 26 Sagainst which face 16 of the tongue may abut should an 201, attempt at forcing the lock be made. Periphery 26 has. a thickness T less than the length of ribs 18, 19.

In the emnbodiment shown the tongue 13 has a spherical hardened ball 27 imbedded which ensures that cutting through the tongue in that region with a hacksaw or the like is resisted. With reference to Figure 4, it can be seen how the ribs 18, 19 are deformed by an attempt to force 6 the lock. Depressions D are formed in the deformable ribs of a length corresponding to thickness T. These depressions D may be substantially step like in configuration and cause periphery 26 to be pressed into the ribs by a forcing attempt. This mating provides some resistance to the tongue being forced out of aperture 25 and hence opening of the door to which the lock is fitted.

It should be appreciated that ribs 18, 19 can be of S any suitable length and provided periphery 26 is of a ;Q thickness less than this length, the tongue functions readily with a variety of different keepers to resist the lock being forced.

Various other changes and modifications may be made to the embodiments without departing from the spirit and scope of the invention as defined in the appended claims.

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Claims (10)

1. A latch tongue for a lock, said latch tongue having a nose portion, opposed side faces adjacent the nose portion and at least one deformable portion extending along one of said faces such that, in use, forcing of the lock causes a periphery of a tongue receiving aperture in a keeper to deform said portion to enable the tongue to resist forcing of the lock.

2. The latch tongue as claimed in claim 1, wherein the at least one deformable portion comprises a rib extending along a said face of the latch tongue.

3. The latch tongue as claimed in claims 1 or 2, wherein 4 f said at least one deformable portion comprises two spaced ribs .t4. extending along adjacent edges of the said one face. fit

4. The latch tongue as claimed in claims 2 or 3, wherein the or each said rib is formed by providing a raised portion which extends beyond the plane of said face of the tongue.

The latch tongue as claimed in claims 2 or 3, wherein the or each said rib is formed by providing a recess in said face where the or each said rib is provided by an unrecessed area adjacent said recess.

6. The latch tongue as claimed in any one of the preceding claims, wherein the at least one deformable portion is present of- on oneAsaid faces. AI l t A'. 1 8

7. The latch tongue as claimed in any one of the keeper preceding claims, wherein said nose portion includes aihepp- engaging face.

8. The latch tongue as claimed in claim 7, wherein said keeper engaging face is inclined to facilitate engagement of the latch tongue into a keeper.

9. A lock including the latch tongue as claimed in any one of the preceding claims.

10. A latch tongue substantially as hereinbefore 0e@oc* described with reference to the accompanying drawing. DATED this 16th day of November 1990 S, WHITCO PTY. LTD. Sao, By their Patent Attorneys CULLEN CO. a iN t