FIELD OF THE INVENTION The present invention relates to a door handle and latch assembly of the kind including a privacy latch apparatus.

BACKGROUND OF THE INVENTION

A door lock apparatus of the low security type, particularly suitable for domestic dwellings, or internal doors in offices, is disclosed, for example, in US patent specification No 4,142,748. This specification discloses a door latch mechanism is operated by inner and outer door handles coupled to a latch shaft extending through the latch mechanism. Handles are coupled to ends of the latch shaft by coupling devices enabling a door to be locked from the inside to prevent entry from the outside, but can still be opened from the inside by normal operation of the handle.

The inside coupling device has limited lost-motion, which is used to operate a cam device to unlock the door on actuation of the inner handle.

A common feature of such arrangements is that the lock can only be unlocked from outside by use of a pointed tool such as a screwdriver or hair pin or the like as disclosed in the abovementioned US patent specification.

The present invention has as its objective to provide a door lock apparatus with a privacy latch which does not require additional unlocking tools so that the door can be unlocked in an emergency situation.

The present invention also seeks to provide a door handle assembly which is relatively easily assembled.

SUMMARY OF THE INVENTION

The present invention is a development of a conventional handle assembly for cooperating with a latch shaft to retract a latch tongue of a latch assembly, the latch tongue protruding from the extremities of a door and adapted to be retracted upon rotation of a handle, the door handle assembly including: a set of door handles for effecting rotation of the latch shaft, at least a first of the set of door handles having an escutcheon plate having an internal connecting cavity; and connecting means for connecting at least one end of the latch shaft to the first handle; the connecting means being retained within the first handle and the cavity; the handle and the cavity being shaped so that when the latch shaft and connecting means are fully assembled, the latch shaft can be retracted from the connecting means upon application of greater than normal axial force to the second handle.

The present invention also provides a door handle assembly including a latch shaft for providing an operative connection between the door handles, the latch shaft being rotatable with the door handles; there being also provided a pivotal latch member mounted relative to the latch shaft for movement between a first position which prevents rotation of the latch shaft and a second position where the latch shaft is free to rotate.

The pivotal latch is preferably pivotally mounted for movement into engagement with a slotted connecting means operatively connected to the latch shaft. The latch member may be overcome by disengagement of the first door handle with the latch shaft to release the latch shaft from the first door handle and thereby allow operation of the door latch.

The invention also provides an escutcheon plate for a door handle assembly, the escutcheon plate including a skirt and a top to define a cavity, the top having a central opening, the cavity having pivotally mounted therein a latch member adapted to co-operate with a snib mounted in a slot in the top for movement between a first position and a second position, the latch member being operatively connected to the snib such that when the snib is in the first position, the latch member co-operates with a connecting means mounted in the escutcheon plate to prevent rotation of the connecting means, and when the snib is in the second position the latch member allows rotation of the connecting means. DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail with reference to the following drawings:

Figure 1 (not to scale) shows a partially exploded front view of part of the door latch mechanism embodying the removable rotary coupling shaft and a handle;

Figure 2 shows a partially exploded rear view of part of Figure 1 including additional features;

Figure 3 is a partial cross-sectional view of part of the assembly of Figures 1 and 2;

Figure 4 is a schematic sectional view of the latch assembly; and Figure 5 is a schematic sectional view of the latch assembly showing the disengaged door handle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To refer to Figure 1 of the drawings there is shown a handle generally designated as 150 and which has a cap 153, intermediate member 154 and body 155 which are assembled to form the completed handle 150. Body 155 has a central boss 156 with a square, axial opening 151 therethrough. Boss 156 has an outer surface 152 generally perpendicular to opening 151.

The handle 150 is used with an escutcheon plate 140 which has a skirt 141 and a top 142. A central opening 143 is provided in top 142.

To connect and hold together handle 150 and escutcheon plate 140, a connecting means 130 is provided. Connecting means 130 has an abutment end 133, an inner end body portion 132, and an outer end body portion 131.

Outer end body portion 131 is of square cross-section and is sized and shaped to fit into, and extend through, opening 143 of escutcheon plate 140, and opening 151 in handle 150. Body portion 131 terminates in two parallelled arms 134 and 135, with there being a gap 136 therebetween. Arms 134 and 135 have at their outer ends barbs 137 and 138 respectively. Barbs 137, 138 engage on surface 152 when handle 150, escutcheon plate 140, and connecting means 130 are assembled to thus hold the assembly together. Arms 134, 135 are preferably biased transversely outwardly to assist and reinforce in their engagement with surface 152. Arms 134, 135 may be generally rectangular (Figures 1 and 2) or slightly tapered (Figure 3) to assist in their passage into and through opening 151. Arms 134, 135 and hence connecting means may be made of any suitable material which provides sufficient resiliency in arms 134, 135 to pass through opening 151 and for 137, 138 to engage on surface 152. Suitable materials include, for example, nylon, plastics or metal.

Inner end body portion 132 is cylindrical and has a square, central opening 139 extending therethrough to gap 136. Body portion 132 is of lesser diameter than opening 143 in escutcheon plate 140 to enable it to pass therethrough. Abutment end 133 extends radially outwardly from body portion 132 and is of larger diameter than opening 143 so that it will contact inner surface 144 of top 142 of escutcheon plate 140 to prevent connecting means 130 from passing completely through opening 143.

When assembled, the length of connecting means 130 should be such that the handle 150, escutcheon plate 140 and connecting means 130 are held together in a relatively close assembly. By virtue of opening 151 and outer end body portion 131 being of similar shape and size, rotation of connecting piece 130 will cause rotation of handle 150, and vice versa. A fixing plate 120 is provided to enable the assembly to be attached to a door. Fixing plate has a generally circular body 121 with a central opening 122 of smaller diameter than abutment end 133. Two threaded, screw-receiving sockets 123 are provided to receive screws (not shown) passing through the door 200 from a similar fixing plate (not shown) on the other side of the door 200. A mounting member 124 having projections 125 is provided, with projections 125 extending beyond the periphery of body 121. Alternatively, projections 125 may be integral with body 121 (see Figure 2). Projections 125 enable escutcheon plate 140 to be securely yet releasably attached to fixing plate 120, as will be understood from the description of Figure 2.

A latch shaft 14 is provided and which is of square cross-section. Latch shaft 14 operatively connects handle 150 to another handle 250 on the other side of the door 200 (Figures 4 and 5). Shaft 14 has at its end two arms 17, each ending with an outwardly directed barb 19, 20 respectively. Between arms 17, 18 is a gap 21 to enable the arms 17, 18 to move towards each other for assembly with connecting means 130, as will be understood from the following description. At the inner end of arms 17, 18 is an outstanding rib 22 extending around latch shaft 14. At assembly, latch shaft 14 is passed through opening 122 in fixing plate 120 and through opening 139 in connecting means 130 such that arms 17, 18 move towards each other and, as barbs 19, 20 enter gap 136, move outwardly and are located within connecting means 130 and extend into gap 136. Barbs 19, 20 engage on body 131, as can be seen in Figure 3. As shaft 14 is of square cross-section, and opening 139 is also square, rotation of shaft 14 will cause rotation of connecting means 130 and thus handle 150, and vice versa. As latch shaft 14 passes through latch mechanism 350 (see Figures 4 and 5) and engages therewith, rotation of either handle 150 or handle 250 will cause rotation of shaft 14, retraction of latch bolt 352, and thus enable door 206 to be opened.

The latch shaft 14 may be made of any suitable material which provides sufficient resiliency in arms 17, 18 to enable them to pass through opening 139 and for barbs 19, 20 to engage on body 131. It is preferable that the material is such that a strong outwardly directed axial force on handle 250 will cause barbs 19, 20 to disengage from body 131 and thus remove shaft 14 from engagement with connecting means 130 and thus handle 150 (figure 5). Examples of such materials include, for example, nylon, plastics or metal. It is not possible for barbs 137, 138 to disengage from surface 152 when shaft 14 is fully engaged in connecting means 130 as arms 17,

18 of shaft 14 are located at least in part in gap 136 between arms 134, 135 and thus it is not possible for arms 134, 135 to move towards each other to cause disengagement.

Figure 2 shows the features of Figure 1 and additional features, which will be understood from the following description. Here, projections 125 are integral with body 121 of plate 120. As can be seen, they extend outwardly and are generally co-planar with the outer surface of plate 120, and are off-set from the inner surface to provide a step 126. Projections 125 engage under radially inwardly directed ledges 145 on skirt 141 of escutcheon plate 140. As ledges 145 have ends 146, this is by a snap- fit at assembly. Therefore, radially extending slots 127 are provided in plate 120 to make plate 120 more flexible and to thus assist assembly.

Mounted to and within the escutcheon plate 140 is a latch member 11 which is somewhat boomerang in shape. One end of latch member 11 has a hole 12 to enable latch member 11 to be pivotally attached to lug 9 by a pin 8 passing through hole 12. The other end of latch member 11 has a tongue 15 extending outwardly therefrom and which is adapted to extend under an L- shaped cover 7 extending over a slot 13 in top 142 of escutcheon plate 140. Mounted within slot 13 is a snib 10 having a hole 6 therethrough at the inner end 5 thereof. The outer end 4 of snib 10 extends outwardly beyond escutcheon plate 140 and is adapted to be grasped or pushed by a person to move snib 10 along slot 13. This therefore moves arm 11.

Mounted centrally on arm 11 is a lug l la which is adapted to selectively co-operate with slots 16 in abutment end 133 of connecting means 130. When snib 10 is moved along slot 13, lug l la engages in one of the slots 16 to thus prevent rotation of connecting means 130. This then prevents rotation of handle 150 and, in consequence, rotation of latch shaft 14 and handle 250. To release the locking, snib 10 is moved back along slot 13 to allow rotation of handle 150 and handle 250 to thus operate the latch mechanism 350. If lug l la is engaged in a slot 16 such that handles 150, 250 cannot be rotated and if it is necessary for handle 250 to be used to release latch mechanism 350 (due to an emergency, or otherwise), the application of a strong, axially-outwardly directed force to handle 250 releases shaft 14 from (locked) connecting means 130 to thus enable handle 250 to be used to rotate latch shaft 14 and thus operate latch mechanism 350. It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

It will also be understood that where the term "comprises" or its grammatical variants, is employed herein, equivalent to the term "includes" and is* not to be taken as excluding the presence of other elements or features.