NZ757272A - Magnetic door latch mechanism and assembly - Google Patents

Abstract

A latch mechanism for a hinged or pivoting door has a latch member with a magnetic latch head and is moveable between extended and retracted positions. A bias spring acts on the latch member to apply a bias force toward the retracted position, wherein the latch member is operatively drawn to its extended position by magnetic force when the latch head aligns with a magnetically susceptible strike member. The latch member is retractable by actuators on each side of the door. The latch mechanism may further include a latch mode mechanism user selectable to configure the latch mechanism into one of: a passage mode, a privacy mode, and an open-passage mode. ended position by magnetic force when the latch head aligns with a magnetically susceptible strike member. The latch member is retractable by actuators on each side of the door. The latch mechanism may further include a latch mode mechanism user selectable to configure the latch mechanism into one of: a passage mode, a privacy mode, and an open-passage mode.

Description

– 1 – Magnetic Door Latch Mechanism and Assembly Field of the invention The present invention relates to a door latch mechanism and assembly that employs a magnetically operated latching action. The latch assembly may be used in a swinging door fitted within a doorway of a building.

Background A door latch assembly conventionally includes a spring-biased latch head that projects from the edge of a hinge-mounted door which is arranged to engage a strike plate in a corresponding door frame. A characteristic of spring-biased moving latches is that the latch head is always resiliently biased to its extended position whether the door is open or closed. When the door closes, an angled face of the latch head engages the exposed edge of a strike plate on the door frame, causing the latch head to momentarily be pushed inwardly against the spring force and, with further pivoting of the door (which may be less than one inch) the latch head then returns to its outward extension within the strike plate aperture by means of the spring force and door latching is complete. This is an almost universal arrangement for automatic latching to occur whenever a door is pivoted to its closed position, so that there is no requirement for a user to manually latch a closed door to keep it from reopening. This is in contrast to a deadbolt which may be driven manually, or by key operation via a lock cylinder or other independent actuation.

An inherent characteristic of a spring-biased latch as outlined above is that a certain level of force is required to be exerted on the door in order to overcome the latch mechanism spring bias force. Moreover, the force required to be exerted in order to latch the door closed may be somewhat greater than the latch spring bias, since force is transferred from the strike plate to the latch head by way of an angled surface contact that also involves frictional losses. Thus, in order to latch the door closed either: the latch spring bias must be overcome by the user operating the door handle or applying closing force to the door; or the latch spring bias must be overcome by a door closing mechanism. – 2 – In many circumstances it is desirable for a door to be operable to latch closed automatically, i.e. without the user needing to manipulate the handle and/or apply closing force to the door. Door closing mechanisms for this purpose are widespread that typically employ a spring and a motion damping device (e.g. hydraulic or pneumatic) to apply force to the door in the closing direction and also control the motion so that the door does not swing violently. One of the difficulties with a door closing and latching system such as this is getting the right balance of spring forces and motion control on the door closing mechanism to provide a desirable door shutting motion while also ensuring the door latches closed reliably. The closing mechanism should not rely on momentum of the door in order to overcome the latch spring bias because then the door may not latch closed reliably if the door shutting momentum is interrupted. Thus, the closing mechanism spring should be capable of applying sufficient force to the door during the final closing movement to overcome the latch spring bias, but on the other hand the closing mechanism force should not be so much as to make the door unduly difficult to open.

A number of the issues outlined above may be addressed, or their impact mitigated, by use of a magnetically operated latch mechanism. In a magnetically operated door latch, the latch head remains retracted while the door is open and is drawn out into its extended configuration by magnetic forces when the latch head aligns with the strike plate aperture in the door frame. This operating principle avoids the aforementioned difficulties that may be associated with overcoming a latch spring bias, and also has other benefits, such as:  improved aesthetics since the latch bolt remains retracted while the door is open;  improved aesthetics since the strike plate does not require a protruding lip to bear against the latch head when closing;  improved safety for users since there is no protruding latch bolt or strike plate lip on which clothing may be caught;  relatively quiet operation since the latch head is not required to impact the strike plate;  the door latch may be equally used on doors that open in either direction, or on doors that swing in both directions. – 3 – Notwithstanding the potential benefits outlined above, there are challenges in designing a magnetically operated door latch that enables the benefits to be realised while also including a full range of features, such as operation in both a 'passage mode' and a 'privacy mode'.

Summary of the invention The present invention provides a latch mechanism for a hinged or pivoting door, comprising: a housing adapted for mounting in or on a door; a latch member supported by the housing for reciprocating movement between an extended position and a retracted position, the latch member including a latch head having a magnetic component; a bias spring acting on the latch member to apply a bias force to the latch member toward the retracted position; wherein the latch member is operatively drawn to its extended position by magnetic force when the latch head in use aligns with a magnetically susceptible strike member mounted on a corresponding door fixture.

The latch mechanism may include an actuator mechanism arranged to act upon the latch member to apply retracting force thereto, the actuator mechanism being operable by means of first and second interfaces accessible from opposite sides of the housing, wherein the first and second interfaces in use couple to respective door handles or the like on opposite sides of the door.

The actuator mechanism may comprise a cam member rotatable about an axis transverse to movement of the latch member, the cam member being rotatable by means of the first and/or second interfaces and arranged to bear upon the latch member to apply force thereon toward the retracted position.

The actuator mechanism may include first and second independently operable actuation members having the respective first and second interfaces. The first and second independently operable actuation members may comprise first and second cam members supported for coaxial rotation about an axis transverse to movement of the latch member, the first and second cam members being independently rotatable by means of the respective first and second interfaces and each arranged to bear upon the latch member to apply force thereon toward the retracted position. – 4 – The latch mechanism may further include a latch mode mechanism user selectable to configure the latch mechanism into one of: a passage mode in which the latch member may be retracted through operation of the actuator mechanism by means of either the first and second interfaces; and a privacy mode in which the latch member may be retracted through operation of the actuator mechanism by means the first interface but not the second interface.

The latch mechanism may further include a latch mode mechanism user selectable to configure the latch mechanism into one of: a passage mode in which the latch member may be retracted through operation of the actuator mechanism by means of either the first and second interfaces; a privacy mode in which the latch member may be retracted through operation of the actuator mechanism by means the first interface but not the second interface; and an open-passage mode in which the latch member is retained in the retracted position and prevented from moving into the extended position.

The latch mode mechanism may be arranged to block retracting movement of the latch member when the privacy mode is selected.

The latch mode mechanism may be arranged to block extending movement of the latch member when the open-passage mode is selected.

The latch mode mechanism may include a mode selection member supported by the housing for indexable movement transverse to the latch member movement, the mode selection member having a respective index position corresponding to each selectable mode.

The mode selection member may have a default position corresponding to said passage mode, the mode selection member being urged toward the default position by a mode selector bias spring. – 5 – The latch mechanism may further include a motion damping mechanism arranged to act on the latch member to as to control extending motion thereof in use. The damping mechanism may comprise a rotational motion damper supported by the housing and having a pinion gear that engages with a rack gear provided on the latch member.

Further aspects, features and advantages of the present invention will be apparent to those of ordinary skill in the art from the accompanying description and drawings.

Brief description of the drawings In order that the invention may be more easily understood, the following detailed description is provided including description of several embodiments, presented by way of example only, and with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of components of a magnetic door latch according to a first embodiment of the invention in a passage version; Figure 2 is an exploded perspective view of components of a magnetic door latch according to the first embodiment including an open-passage mode; Figures 3A and 3B are cut-away perspective views of the assembled magnetic door latch of Figure 2, illustrating engagement and disengagement of the open-passage mode; Figure 4 is an exploded perspective view of components of a magnetic door latch according to the first embodiment in a privacy version; Figures 5A and 5B are perspective views of the assembled magnetic door latch of Figure 4 with nearside housing removed, illustrating engagement and disengagement of the privacy mode; Figures 6A and 6B are side views corresponding to Figures 5A and 5B, respectively; Figures 7A, 7B and 7C are side views of the magnetic door latch of Figure 4, with nearside housing removed, illustrating operation of the cam mechanism; Figure 8 is an exploded perspective view of components of a magnetic door latch of Figure 4, including a latch motion damper; Figure 9 is a perspective view of the assembled magnetic door latch of Figure 8, with nearside housing removed and damper component displaced; – 6 – Figures 10A and 10B are partial cutaway perspective views of the assembled magnetic door latch of Figure 8 with latch retracted and extended, respectively; Figure 11 is an exploded perspective view of components of a magnetic door latch according to a second embodiment of the invention including selectable privacy and passage modes; Figure 12 a perspective sectional view of the assembled magnetic door latch of Figure 11; Figures 13A and 13B are views similar to Figure 12, illustrating engagement and disengagement of the privacy mode; Figure 14 is a view similar to Figure 12 diagrammatically indicating three different ways in which the privacy mode may be disengaged; Figures 15A, 15B and 15C are partial cutaway perspective views of the magnetic door latch according to the second embodiment illustrating disengagement of privacy mode and retraction of the latch through use of the cam mechanism; Figures 16A and 16B are perspective sectional views of the magnetic door latch according to the second embodiment illustrating disengagement of privacy mode by way of the cam mechanism; and Figures 17A and 17B are views similar to Figure 12 of a modification of the second embodiment magnetic door latch that permits open passage mode.

Detailed description Several versions and variations of magnetic door latches according to embodiments of the invention are illustrated in the accompanying drawings and described below.

On a note of terminology, features of the door latch assembly, mechanisms and components may be described herein using reference to relative orientations or directions such as left/right, upper/lower, forward/back, and the like. In general such terms are to be understood as referring to the assembled latch mechanism as if it were installed in a door, where the direction in which the latch head extends is considered the 'forward' direction.

Thus, considering the latch head extension direction as forward, the door has left and right faces. – 7 – In the description that follows, with regard to door structures in which the door latch may be installed, reference may also be made to the 'inside' or 'internal' and 'outside' or 'external' which are commonly used terms that delineate features that lie to one side or the other of the doorway. It should be appreciated these terms are generally used in a relative sense that does not necessarily imply or import other meanings or features unless clearly stated. Moreover, when considering the door having a forward direction as defined by the latch head extension, the left-hand side may be the 'inside' and the right-hand side may be the 'outside', or vice versa.

A 'passage' set is typically used for interior doors that don't need locks but do require a latching feature. These types of latches are often installed on doors in a general living area, for example. A 'privacy' set, on the other hand, is used where locking functionality is desired from one side of the door, such as bathrooms and bedrooms. A privacy latch may have a pin that enables locking from the inside, and an emergency release access hole on the outside.

Certain features of a door latch are similar on both sides of the door when installed. For example, in a passage set latch each side of the door has a respective knob, handle or other actuator that can be user-operated from that side of the door. For ease of reference, similar features of the embodiments that are provided on each side of the door are designated by a reference numeral followed by a suffix 'A' or 'B' corresponding to respective sides of the door. It will be appreciated that A or B may arbitrarily correspond to left or right, inside or outside, unless otherwise stated.

A 'passage' version of a magnetic door latch 10 according to a first embodiment of the invention is seen in an exploded perspective view of its components in Figure 1. The general structure of the door latch 10 comprises an elongate housing having components 11A and 11B which, when assembled together, support therein an elongate latch body slider 50. The housing components 11A, 11B are secured together at the rear by way of an assembly screw 15. The first housing component 11A has a faceplate 12 at its forward end that lies flush with the swinging edge of a door when installed, in conventional manner. Thus, when installed the rest of the housing and components therein lie within – 8 – the door structure, apart from the latch head 52 which selectively extends through the faceplate aperture 13, as explained below.

When assembled the latch body slider 50 is supported by the latch housing 11 for longitudinal reciprocal movement between a retracted position and an extended position.

In the extended position the latch head 52 on the end of the latch body slider 50 projects through the faceplate aperture 13 (and in use engages with the cavity of a strike plate or the like). A magnet 54 is carried within the latch head 52. In the retracted position the entire latch body slider including head 52 resides within the latch housing, the end surface of the latch head 52 being generally flush with the end surface of the faceplate 12.

Rearward travel of the latch body slider 50 is limited by a rear stop formation 17 (part of the housing component 11B) against which a slider rear plate 51 bears at the rearward limit of movement. The latch body slider 50 is urged toward its retracted position by means of a latch return spring 58 which is installed to act between the slider rear plate 51 and a latch spring boss 18 formed on the housing component 11A. The latch return spring 58 acts in compression between the latch spring boss 18 and the rear plate 51, biasing the latch body slider to the retracted position in the absence of magnetic forces acting on the magnet 54 in in the latch head 52.

The magnetic door latch 10 also includes a handle cam 30 which is rotatably supported within the housing 11 and within a cam receiving slot 55 of the slider 50. The handle cam 30 is oriented to have its axis of rotation transverse to the longitudinal extent of the slider 50 whereby a cam-handle interface 32 is accessible through an aperture 14B of the housing component 11B, with a similar cam-handle interface accessible through a corresponding aperture in housing component 11A (not labelled). The respective cam- handle interfaces 32 engage with door handles or the like on opposite sides of the door when the latch is installed, for user operation of the latch. In this passage set latch 10, the handle cam 30 is a unitary component that includes two radially projecting cam heads 33.

The cam heads 33 are adapted to engage latch body cam shoulders 56 formed on the latch body slider 50 to the rear of the cam receiving slot 55.

Operation of the passage set latch 10 when installed for use in a door is as follows. When the door is open the latch body slider 50 is driven to its retracted position – 9 – by means of the latch return spring 58, whereby the latch head 52 is retracted from the face plate 12. When the door is closed the latch head 52 aligns with a magnetically susceptible strike plate in the door frame (not seen). Magnetic attraction forces between the magnetic latch head and the strike overcome the bias force of the latch return spring 58, causing the slider 50 to move into its extended position wherein the latch head 52 projects out through the faceplate aperture 13 and engages with the strike plate, securing the door closed. To open the door, a user on either side of the door may turn the respective handle (not shown) which causes rotation of the handle cam 30. Rotation of the handle cam causes the cam heads 33 to engage the latch body cam shoulders 56, making the slider 50 move in the rearward direction toward the retracted position. When the latch head it fully retracted by operation of the handle the door may be opened by the user by pushing or pulling the door handle as appropriate. Upon release of the door handle by the user the latch body slider 50 is maintained in the retracted position by the spring 58.

Figure 2 is an exploded perspective view of components of a magnetic door latch according to the first embodiment, further including a latch mode mechanism 60 enabling the latch to function in an open-passage mode. In open-passage mode the latch does not engage with the strike when the door is closed, allowing the door to be freely pushed or pulled open without the user needing to operate the handle. For use in open- passage mode the door might typically be provided with a spring closing mechanism or the like to return the door to the closed position and maintain the door closed in the absence of user interaction.

The latch mode mechanism 60 includes inside and outside latch pins 62A, 62B that are aligned with one another parallel to and forward of the handle cam axis. Each latch pin 62 has a user-operable portion that extends outside of the housing 11, and an engaging portion that projects into the housing through a respective hole (not labelled).

The latch pin engaging portions engage into respective sides of a latch lock component 64. The latch pins 62 and latch lock 64 are supported in the housing so as to be displaceable from side to side between an engaged position and a disengaged position.

The latch mode mechanism 60 is biased toward the disengaged position of the latch lock by means of a latch lock spring 68. – 10 – When the magnetic latch 10 is in its retracted configuration the open-passage mode may be engaged by displacing the latch lock 64 to its right-hand-side (engaged) position, by pushing on the pin 62A or pulling on the pin 62B. As explained below, this causes a flange of the latch lock to engage with a latch body lock detail formed on the slider 50 that prevents the slider from moving forward. A latch lock position slider 65 is mounted within the housing 11A and held in place by a slider retainer plate 67 and slider retainer plate screw 61. The latch lock position slider 65 is mounted between the inside of the housing 11A and the slider retainer plate 67. The latch lock position slider 65 is mounted to permit a small amount of forward-rearward movement, and is urged toward its rearward position by a mode lock spring 66.

Figures 3A and 3B are cut-away perspective views of the assembled magnetic door latch of Figure 2, illustrating engagement and disengagement of the open-passage mode. In Figure 3B the open-passage mode is disengaged wherein the door latch 10 is free to operate in passage mode as described hereinabove in connection with Figure 1.

When the latch body slider 50 is in its forward position (latch head 52 extended) as seen in Figure 3B the latch mode mechanism is prevented from moving to its engaged position by interference between the latch body slider and the latch lock 64. Moreover, the latch mode mechanism is biased toward this disengaged position by force of the latch lock spring 68.

When the latch is retracted (e.g. as seen in Figure 3A) the latch mode mechanism 60 may be engaged to place the magnetic latch 10 in open-passage mode. This is effected by movement of the latch pins 62 and associated latch lock 64 in the direction indicated by arrow "E" from the disengaged to the engaged position shown in Figure 3A.

In the engaged position a flange on the latch lock 64 engages with a latch body lock detail 59 of the slider 50 which prevents forward movement of the slider. The latch lock 64 is retained in the engaged position, against the bias force of latch lock spring 68, by a latch lock detent 63 which bears against a latch lock position slider detent 69 (spring 68 is not required for open passage mode as a stand-alone feature). In order to disengage the open-passage mode the user may push or pull one of the latch pins 62 in the direction – 11 – indicated by arrow "D" to overcome the engagement of detents 63, 69 and return the latch lock 64 to its disengaged position (Figure 3B).

Figure 4 is an exploded perspective view of components of a magnetic door latch 100 according to the first embodiment in a privacy version. Components that are substantially common with the magnetic door latch 10 are designated with common reference numerals preceded by the digit "1". Comparing Figure 4 with Figure 2 it will be apparent that there are many similarities between the latch 100 and the latch 10.

However, in the latch 100 the latch mode mechanism 160 implements a privacy mode selector as opposed to latch mode mechanism 60 which implements the previously described open-passage mode. When the privacy mode is engaged the latch head 152 is held in its extended position (keeping the door closed and latched), as compared to the open-passage mode in which the latch head is held in its retracted position.

Privacy mode allows for the magnetic latch 100 to be selectively held with the latch head in an extended position whilst the door is closed. Typically the latch will be arranged so that a user on the inside of the door can activate the privacy mode to prevent a person on the outside of the door from operating the latch. In the latch 100 shown in Figure 4, the privacy mode is selectable by the inside use by pushing on the latch pin 162A which shifts the latch lock 164 into a position that engages with a lock detail (159 seen in Figures 5-7) on the latch body slider that prevents the latch body slider 150 from being retracted.

The privacy mode is intended to be engaged or disengaged by a user on the inside of the door only, although there are circumstances (e.g. in an emergency) when it may be desirable to allow for disengagement of the latch lock from the outside. From the outside the privacy mode of the latch 100 can only be disengaged (not engaged) by use of the outside latch pin 162B. The latch pin 162B is concealed by a fascia (not shown) when the latch is installed and can only be manipulated by the user by pushing through a small outside locking pin access hole. On the other hand, a user on the inside can engage the privacy mode by pushing on the inside latch pin 162A, or can disengage the privacy mode by pulling on that latch pin. – 12 – Figures 5A and 5B are perspective views of the assembled magnetic door latch 100 with nearside (outside) housing removed, illustrating engagement and disengagement of the privacy mode. In Figure 5B the latch head 152 is shown extended (ordinarily in this configuration engaged with a strike plate, not shown), and with the privacy mode engaged from the inside by the user pushing on the inside latch pin 162A in the direction indicated by arrow "E". When so configured, the latch body slider 150 is restricted from rearward displacement by engagement of the latch lock 164 with a latch body lock detail 159 on the slider 150. The privacy mode can be disengaged by pulling on the inside latch pin 162A, or by pushing on the outside latch pin 162B through the access hole in the direction indicated by arrow "D".

Figures 6A and 6B are side views corresponding to Figures 5A and 5B, respectively. In Figure 6A the latch 100 is shown in its neutral state – the latch slider 150 is retracted by the latch return spring 158. In this configuration the latch lock 164 is inoperable. Figure 6B shows the latch 100 in its activated state wherein the latch head 152 is pulled out of the housing by the magnetic attraction of the strike (not shown). In this configuration the latch lock 164 is able to engage with the latch body lock detail 159 to prevent the latch head from retracting.

The privacy mode can also be disengaged by manipulating the door handle, but only from the inside of the door. For this purpose the handle cam 130 in the door latch 100 is split into two coaxial parts 130A and 130B (operable by the inside and outside door handles, respectively). The two handle cams 130A and 130B are mounted so as to be individually rotatable by respective inside and outside door handles (not shown) only. The cam head 133A of the inside handle cam 130A is arranged to interact with the spring biased latch lock position slider 165 so that rotation of the inside door handle can disengage privacy mode whereas the outside handle cam 130B, which is separately rotatable, does not affect the latch mode mechanism 160.

Figures 7A, 7B and 7C are side views of the magnetic door latch 100 of Figure 4, with nearside (inside) housing removed, illustrating operation of the cam mechanism to release the privacy mode and withdraw the latch head. In Figure 7A the latch 100 is seen in its activated state (latch head extended) and with the privacy mode engaged (latch lock – 13 – 164 engaged with latch body lock detail 159 preventing retraction of the latch body slider 150). The end 175 of the latch lock position slider can be seen received within an axially- aligned groove 135 formed for this purpose in the centre of the inside cam head 133A.

With the end 175 of the latch lock position slider received in the groove 135 the slider detent 169 is able to engage with the latch lock detent 163 to maintain the latch lock 164 in its privacy mode position. If the inside cam 130A is rotated in either direction the cam head 133A presses the latch lock position slider 165 forward releasing the latch lock 164 (Figure 7B). Further rotation of the inside cam 130A causes the cam head 133A to engage the latch body cam shoulder 156A, retracting the latch body slider 150 and latch head 152 (Figure 7C).

Figures 8, 9 and 10 illustrate the magnetic door latch 100 further incorporating a latch damper mechanism. Figure 8 is an exploded perspective view of components of the magnetic door latch including a latch motion damper; Figure 9 is a perspective view of the assembled magnetic door latch of Figure 8, with nearside housing removed and damper component displaced; and Figures 10A and 10B are partial cutaway perspective views of the assembled magnetic door latch of Figure 8 with latch retracted and extended, respectively.

Operation of the magnetic door latch shown in Figures 8, 9 and 10 is essentially the same as described hereinabove in connection with Figures 4-7, although at least the forward motion of the latch body slider 150 (and thus the latch head 152) is controlled by a damper 170. The body of the latch damper 170 is in use mounted within an aperture formed in the forward side wall of the housing 111B. The damper 170 has a damper pinion gear 171 that projects into the housing to engage with a latch damper rack 172 formed on a forward portion of the latch body slider 150. The damper 170 is operative to apply damping resistance to rotational motion of the pinion gear 171 which in turn is applied to the linear motion of the slider 150. The purpose of the damper is to slow motion of the latch head 152 when it is, in use, magnetically engaged by the strike, to prevent or reduce noise during the latching operation. The damper 170 may preferably function to damp motion of the slider 150 primarily in the forward direction, so that the rearward retracting motion of the latch is less impeded. Although a rotary damper is shown in the – 14 – drawings a linear damper device may alternatively be employed, in which case the rack and pinion coupling would not be required.

Figure 11 is an exploded perspective view of components of a magnetic door latch 200 according to a second embodiment of the invention including selectable privacy and passage modes. Figure 12 a perspective sectional view of the assembled magnetic door latch 200. The magnetic door latch 200 has two housing portions 211A and 211B that fit together to form an elongate housing that supports a latch slider 250 for reciprocal linear movement between retracted and extended positions. The housing is in use installed within a door, with the rear of the housing portions 211A, 211B being held together by a rear plate 220 and the front secured within a latch body front housing 248. When installed the faceplate 212 of the front housing 248 typically lies substantially flush with the swinging edge surface of the door. The front housing 248 has a generally cylindrical shape with external longitudinal ridges that facilitates an interference-fit installation of the latch 200 into a circular hole formed in the door. A corresponding strike 280 is installed in the door frame by means of strike plate 281. The strike 280 has a cavity 285 that, when the door is closed, aligns with the faceplate aperture 213 of the latch, and includes a magnet 284 with magnetic polarity arranged to attract the latch magnet 254 when the latch faceplate aperture 213 and strike cavity align.

The latch slider 250 affixes to the latch head 252 by means of a latch head assembly screw 249 which passes through the latch slider, latch head and magnet locator 253 to secure the latch magnet 254 within the front of the latch head. The housing portions 211A and 211B are secured to the latch body front housing 248 by way of a front housing assembly screw 247. When assembled the front housing assembly screw passes through a slot in the latch slider 250 behind the latch head – the slot allowing for an operational range of linear movement of the slider relative to the housing for extension and retraction of the latch head. The latch slider 250 is biased to the retracted position of the latch head by a latch slider spring 258 that acts between a latch spring boss 218, formed as part of the housing portion 211A, and the rear of the slider 250. The latch slider spring 258 ensures that the latch head remains retracted when the door is open. – 15 – The latch housing supports inside and outside cam members 230A, 230B for rotational movement within respective circular handle apertures 214A and 214B formed in the side faces of the housing portions. The cam members 230A, 230B are coaxial and individually rotatable by means of respective inside and outside door handles (not shown) that engage with respective cam-handle interfaces 232A, 232B. The cam members reside within a cam receiving slot 255 of the slider 250. The inside and outside cam members each have a respective cam head 233A, 233B operable to retract the latch slider by action on respective latch slider cam shoulders 256A, 256B.

The main functional difference between the magnetic latch 200 and the previously described latch 100 is that the latch 200 allows for multi-mode operation. Specifically the magnetic latch 200 provides both a privacy mode and a passage mode governed by operation of the locking mode mechanism 260, the components and functions of which are described below.

The components of the locking mode mechanism 260 include inside and outside user-operable locking pins 262A and 262B. When the latch 200 is installed in a door the inside locking pin 262A projects from the inside of the door adjacent the door handle which enables it to be pushed or pulled by the user to engage the different modes of the latch. On the other hand the outside locking pin 262B does not have a projection that extends beyond the door surface and is accessible to the outside user only through an outside locking pin access hole, such that the locking pin 262B can only be pushed from the outside. The inside and outside locking pins engage with opposite ends of a locking pin body 264 within the latch housing whereby manipulation of the inside and/or outside locking pins 262A, 262B effects displacement of the locking pin body, orthogonal to the latch slider axis, into two or more positions corresponding to the different latching modes.

A locking pin compression spring 268 is located between the locking pin body 264 and the interior surface of the outside housing 211B, coaxial with the shaft of the outside locking pin 262B. The locking pin spring 268 provides a biasing force on the locking pin body toward a passage mode of the latch, as explained further below.

The locking pin body 264 is arranged within the locking mode mechanism 260 to interact with a locking pin catch 265. The locking pin catch 265 is mounted adjacent to the – 16 – interior surface of the inside housing 211A by means of a locking pin catch case 267 which is secured in place by the front housing assembly screw 247. The locking pin body 264 extends through a window in the locking pin catch 265 which is supported to allow for a small amount of linear movement parallel to the axis of the latch slider. The position of the locking pin catch 265 relative to the locking pin body 264 and inside handle cam 230A is biased by two locking pin catch springs 266. The end of the locking pin catch 265 that is opposite to the springs 266 has a cam follower 275 that rests in a groove 235 formed in cam head 233A when the inside cam 230A is in its neutral position. Rotation of the inside cam 230A in either direction causes the cam head 233A to bear on the cam follower 275 resulting in displacement of the locking pin catch 265.

The purpose of the locking pin catch 265 is to engage with the locking pin body 264 to hold the locking pin body in place corresponding to a selected latching mode until the mode is changed through user input. To this end the locking pin body 264 has a series of mode position detent grooves 263 arranged to engage with the locking pin catch detent 269, which is urged into engagement by the springs 266. In the absence of user input the engagement by the locking pin catch detent 269 is sufficient to hold the locking pin body 264 in a selected mode position against the force of the locking pin spring 268.

User input may be supplied by pushing or pulling on the inside locking pin 262A, pushing on the outside locking pin 262B, or turning the inside door handle causing rotation of the inside handle cam 230A. Pulling or pushing on one of the locking pins 262 directly moves the locking pin body 264 from one mode position to another. Rotation of the inside handle cam 230A causes displacement of the locking pin catch 265, which disengages the locking pin catch detent 269 from the mode position detent groove 263 sufficiently for action of the locking pin spring 268 to move the locking pin body 264.

Figures 13A and 13B are views of the magnetic latch 200 similar to that seen Figure 12, illustrating the privacy mode engaged and disengaged configurations respectively.

The privacy disengaged configuration shown in Figure 13B is the resting state of the locking mode mechanism 260 according to the bias force provided by the locking pin spring 268. While the locking mode mechanism is so configured the latch 200 is operable – 17 – in passage mode (as previously described) wherein the latch body slider 250 can move between extended and retracted positions by operation of either the inside or outside handles.

When the latch body slider 250 is in its extended position as seen in Figure 13A the locking mode mechanism 260 can be configured to engage the privacy mode of the latch. In privacy mode the latch head can only be retracted by operation of the inside handle, not from the outside. This is accomplished by preventing the retracting movement of the latch body slider 250. Specifically, as can be seen circled at L2 in the Figure, when configured in privacy mode a portion of the locking pin body 264 engages with detail 259 on the latch body slider 250 which blocks rearward displacement of the latch body slider and latch head. To engage the privacy mode a user must push on the inside locking pin 262A with sufficient force to overcome the locking pin spring 268 as well as the spring loaded catch detent 269. When configured in the privacy mode the locking pin body 264 is held in place by engagement of the catch detent 269 in a respective mode position detent groove 263, as seen circled at L1 in the Figure. If the latch slider body 250 is in a retracted position (e.g. as shown in Figure 13B) the locking pin body 264 is prevented from being configured into its privacy mode position by interference with the detail 259 on the latch body slider.

Disengagement of privacy mode back into passage mode of the latch 200 can be done by pulling on the inside locking pin 262A or pushing on the outside locking pin 262B.

Alternatively privacy mode may be disengaged by user operation of the inside handle effecting rotation of the inside cam 230A. These three means of disengaging privacy mode for the latch 200 are diagrammatically indicated by arrows R1, R2 and R3 shown in Figure 14.

Figures 15A, 15B and 15C are partial cutaway perspective views of the magnetic door latch 200 illustrating disengagement of privacy mode and retraction of the latch through rotation of the inside handle cam. Figures 16A and 16B are perspective sectional views of the magnetic door latch 200 substantially corresponding to Figures 15A and 15B respectively. – 18 – Referring to Figures 15A and 16A the latch 200 is shown with privacy mode engaged wherein the latch head 252 is extended and residing within the cavity 285 of the strike 280. In this configuration the locking pin body 264 is positioned at its furthest extent toward the 'outside' of the latch such that the outside locking pin 262B projects out from the outside housing portion 211B and the inside locking pin 262A is against the inside housing portion 211A. In this position of the locking pin body 264 the latch slider 250 is prevented from retracting by the latch body lock detail 259 (not seen in these drawings).

Figure 16A shows that with the locking mode mechanism 260 engaged in privacy mode the catch detent 269 is engaged in the mode position detent groove 263 that is nearest to the inside locking pin 262A. Figure 15A shows that the cam follower 275 of the locking pin catch 265 is seated in the groove 235 formed in the middle of the inside cam head 233A Referring to Figures 15B and 16B the latch 200 is shown following initial rotation of the inside cam 230A by user operation of the inside door handle. Initial rotation of the inside cam 230A moves the groove 235 out of alignment with the cam follower 275 wherein the cam head 233A forces displacement of the locking pin catch 265 against the bias of springs 266 (best seen in Figure 15B). The small displacement of the locking pin catch 265 effected by rotation of the cam is enough for the catch detent 269 to clear the mode position detent groove 263 (Figure 16B) sufficiently for the locking pin body 264 to move under action of the locking pin spring 268 bias force. In other words, rotation of the inside cam 230A releases engagement of the catch 265 with the locking pin body 264 allowing the locking pin body to return to its spring biased position corresponding to passage mode configuration of the latch.

Further rotation of the inside cam 230A (Figure 15C) causes the cam head 233A to meet the corresponding latch body cam shoulder 256A and move the latch body slider 250 to draw the latch head 252 away from its magnetic attraction with the strike 280.

Once the door is open and the latch head is no longer aligned with the strike the latch body slider is retained in the retracted position by the return spring 258.

Figures 17A and 17B are perspective sectional views of the assembled magnetic door latch according to a second embodiment including a modification that permits the magnetic door latch to also operate in open-passage mode. The modification to the latch – 19 – 200 is simply that the outside locking pin 262B has a longer shaft length such that the locking pin body 264 can adopt three different mode positions corresponding to an open- passage mode, an ordinary passage mode, and a privacy mode. In each mode position of the locking pin body 264 the catch detent 269 is aligned to engage with a respective mode position detent groove 263.

Figure 17A shows the latch 200 with the locking mode mechanism 260 configured in the neutral passage mode in which the latch head is able to extend and engage the strike and each of the inside and outside handles is independently operable to retract the latch head. From the neutral passage mode the inside locking pin 262A can be pushed to configure the latch into the privacy mode as previously described. Moreover, in this embodiment the inside locking pin 262A can also be pulled to configure the latch into the open-passage mode as shown in Figure 17B. The locking mode mechanism 260 is only able to adopt the open-passage mode configuration while the latch head is retracted due to the open-passage slider detail 246 on the latch body slider 250. While the latch head is extended the open-passage slider detail 246 is arranged to engage the locking pin body 264 to prevent the locking pin body from moving into the open-passage mode position.

When the latch head is retracted and the locking pin body 264 is placed in the open- passage mode position the locking pin body engages the open-passage slider detail 246 to prevent the latch body slider from moving forward, as shown in Figure 17B.

The latch 200 is designed for ease of installation. The vertical and lateral dimensions of the mechanism, apart from the locking pins 262, are within the circular profile of the latch body front housing 248. This allows the latch without the locking pins to be installed into a circular bore formed in the door. The latch may be installed in either orientation (i.e. the 'privacy' selection feature may be on either side of the door), and the locking pins are inserted after the mechanism is secured in the door.

The invention has been described by way of non-limiting example only and many modifications and variations may be made thereto without departing from the spirit and scope of the invention. – 20 – The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. – 21 –

Claims (13)

CLAIMS 1.:

1. A latch mechanism for a hinged or pivoting door comprising: a housing adapted for mounting in or on a door; 5 a latch member supported by the housing for reciprocating linear movement between an extended position and a retracted position, the latch member including a latch head having a magnetic component; a bias spring acting on the latch member to apply a bias force to the latch member toward the retracted position; 10 wherein the latch member is operatively drawn to its extended position by magnetic force when the latch head in use aligns with a magnetically susceptible strike member mounted on a corresponding door fixture.

2. A latch mechanism according to claim 1 including an actuator mechanism 15 arranged to act upon the latch member to apply retracting force thereto, the actuator mechanism being operable by means of first and second interfaces accessible from opposite sides of the housing, wherein the first and second interfaces in use couple to respective door handles or the like on opposite sides of the door. 20

3. A latch mechanism according to claim 2 wherein the actuator mechanism comprises a cam member rotatable about an axis transverse to movement of the latch member, the cam member being rotatable by means of the first and/or second interfaces and arranged to bear upon the latch member to apply force thereon toward the retracted position.

4. A latch mechanism according to claim 3 wherein the actuator mechanism includes first and second independently operable actuation members having the respective first and second interfaces. 30

5. A latch mechanism according to claim 4 wherein the first and second independently operable actuation members comprise first and second cam members supported for coaxial rotation about an axis transverse to movement of the latch member, the first and second cam members being independently rotatable by means of the – 22 – respective first and second interfaces and each arranged to bear upon the latch member to apply force thereon toward the retracted position.

6. A latch mechanism according to any one of claims 2 to 5, further including a latch 5 mode mechanism user selectable to configure the latch mechanism into one of: a passage mode in which the latch member may be retracted through operation of the actuator mechanism by means of either the first and second interfaces; and a privacy mode in which the latch member may be retracted through operation of the actuator mechanism by means the first interface but not the second interface.

7. A latch mechanism according to any one of claims 2 to 5, further including a latch mode mechanism user selectable to configure the latch mechanism into one of: a passage mode in which the latch member may be retracted through operation of the actuator mechanism by means of either the first and second interfaces; 15 a privacy mode in which the latch member may be retracted through operation of the actuator mechanism by means the first interface but not the second interface; and an open-passage mode in which the latch member is retained in the retracted position and prevented from moving into the extended position. 20

8. A latch mechanism according to claim 6 or 7 wherein the latch mode mechanism is arranged to block retracting movement of the latch member when the privacy mode is selected.

9. A latch mechanism according to claim 7 wherein the latch mode mechanism is 25 arranged to block extending movement of the latch member when the open-passage mode is selected.

10. A latch mechanism according to claim 8 wherein the latch mode mechanism includes a mode selection member supported by the housing for indexable movement 30 transverse to the latch member movement, the mode selection member having an index position corresponding to each selectable mode. – 23 –

11. A latch mechanism according to claim 10 wherein the mode selection member has a default position corresponding to said passage mode, the mode selection member being urged toward the default position by a mode selector bias spring. 5

12. A latch mechanism according to any preceding claim further including a motion damping mechanism arranged to act on the latch member to as to control extending motion thereof in use.

13. A latch mechanism according to claim 12 wherein the damping mechanism 10 comprises a rotational motion damper supported by the housing and having a pinion gear that engages with a rack gear provided on the latch member. – 24 –