WO2009000008A1

WO2009000008A1 - Magnetic latching mechanism

Info

Publication number: WO2009000008A1
Application number: PCT/AU2007/000870
Authority: WO
Inventors: Franz Kocijan
Original assignee: Magswitch Technology Worldwide Pty Ltd
Priority date: 2007-06-22
Filing date: 2007-06-22
Publication date: 2008-12-31

Abstract

A magnetic latching arrangement comprising: a first surface; a first substantially cylindrical magnetically active unit having a distal and proximal end with the distal end being located adjacent one side of the first surface, the unit being located in a predetermined axial rotation by means of a resilient biasing force; a latching bolt attached to the substantially cylindrical magnetically active unit; wherein upon placement of a second predetermined magnetic field adjacent a second side of the first surface near the distal end of the unit, the unit is caused to rotate around an axis thereby causing at least one end of the latching bolt to undergo a translation from a first spatial position to a second spatial position.

Description

Magnetic Latching Mechanism FIELD OF THE INVENTION

[0001] The present invention relates to the field of magnetic latching and, in particular, discloses a permanent magnet latching device suitable for use as a latch or lock mechanism.

BACKGROUND OF THE INVENTION

[0002] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. [0003] The utilisation of permanent magnet devices to act as latching or locking mechanisms are known. For example, US Patent 5485733 discloses a latching mechanism driven by permanent magnets wherein the permanent magnet pivot on demand to provide a latching or locking mechanism. Similarly, US Patent 5076623 also discloses a latching mechanism with a permanent magnet being engageable and turnable or slideable between an engaged position and disengaged position. Similarly, US Patent 3744833 discloses a magnetic latching device that utilises magnetic attraction to latch any magnetic device.

[0004] The foregoing prior art is unsuitable for use in particular environments. For example, where heavy lifting of a latching door or access panel is required the arrangements are likely to be significant inferior.

[0005] Further, the arrangements can be difficult to manufacture and may exibit failure modes that limit their operation. SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide for an alternative form of magnetic latching device which overcomes or amoralities disadvantages in utilisation of prior art devices. [0007] In accordance with a first aspect of the present invention, there is provided a magnetic latching arrangement comprising: a first surface; a first substantially cylindrical magnetically active unit having a distal and proximal end with the distal end being located adjacent one side of the first surface, the unit being located in a predetermined axial rotation by means of a resilient biasing force; a latching bolt attached to the substantially cylindrical magnetically active unit; wherein upon placement of a second predetermined magnetic field adjacent a second side of the first surface near the distal end of the unit, the unit is caused to rotate around an axis thereby causing at least one end of the latching bolt to undergo a translation from a first spatial position to a second spatial position. [0008] The resilient biasing force can be provided by magnetic interaction between the unit and at least one biasing magnet placed adjacent the magnetically active unit. The number of biasing magnets can be two. The latching bolt can be rotationally mounted to the distal end of the unit and the end can be translated radially relative to the axis of the unit upon rotation of the unit. The unit preferably can include a diametrically magnetised magnet substantially adjacent the proximal end of the unit.

[0009] The second predetermined magnetic field can be formed from a^'second diametrically magnetised magnet having a controllable magnetic force, placed adjacent a second side of the surface and, upon activation of the controllable magnetic force, the unit and the second diametrically magnetised magnet clamp the surface in between. [0010] The first surface preferably can include a predetermined profile and the second diametrically magnetised magnet preferably can include a mating profiled surface which mates with the first predetermined profile upon activation of the latch. The latching arrangement can be utilised to lock or unlock a planar panel. The biasing magnet can comprise an annular ferromagnetic magnet. The second diametrically magnetised magnet preferably can include a handle grip for utilisation upon clamping to move the first surface. In some embodiments, the unit experiences an attractive force relative to the second predetermined magnetic field. In other embodiments, the unit experiences a repulsive force relative to the second predetermined magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:

Fig. 1 illustrates a magnetic field activation device;

Fig. 2 illustrates a sectional view of a first embodiment of the present invention;

Fig. 3 illustrates the magnetic fields associated with a diametrically magnetised magnet;

Fig. 4 to Fig. 15 illustrates photographs of a prototype implementation of the first embodiment; Fig. 16 illustrates an exploded perspective view of a second embodiment;

, . Fig. 17 illustrates a side plan view of the second embodiment;

Fig. 18 illustrates a bottom plan view of a second embodiment;

Fig. 19 illustrates a side perspective view of the mounting plate of the second embodiment; and Fig. 20 to Fig. 25 illustrates one prototype form of implementation of the alternative embodiment. DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

[0012] In the preferred embodiment, there is provided a magnetic latching mechanism that allows for simplified operation and rapid deactivation of the latch on demand.

[0013] Whilst the preferred embodiments will be described in respect of providing latching mechanism for manhole access covers, it will be readily evident to those skilled in the art that the preferred embodiment is not limited thereto and can be readily utilised in other environments where simplified latching capabilities are required.

[0014] The preferred embodiment utilises permanent magnet devices to activate and deactivate the latch. The permanent magnet devices preferably utilise rear earth magnets which are known to have an increased level of magnetic intensity. [0015] The preferred embodiment makes particular use of the magnetic switching device disclosed in US Patent 7012495 the contents of which are hereby incorporated by cross reference. The device disclosed (hereinafter called a magnetic switching device) is a switchable magnetic device which provides for simple switching of the intensity of a magnetic field between an effective "on" and "off state. The device of the aforementioned patent is illustrated in an exploded perspective in Fig. 1. The device operates to turn on and off the effective strength of a magnetic field upon rotation of arm 10. In the preferred embodiment the device of Fig. 1 is utilised to activate and deactivate a latching mechanism thereby allowing access to, in the examples provided, a manhole cover. [0016] Turning now to Fig. 2, there is illustrated a schematic sectional view drawn in schematic to illustrate the principals of the latching magnet operation of the preferred embodiment. The latch is formed within a manhole cover 50 which is inserted within a manhole formed within the surface 51. The latch locking and unlocking is based around the movement of two pins 52, 53 which engage mating surfaces 54, 55 of the manhole so as to lock the manhole in place. The pins 52, 53 are retractable upon activation of the magnetic latch so as to release the cover 50.

[0017] The Pins 52, 53 can be formed of stainless steel when utilised in a corrosive environment. Two spring pins 60, 61 are provided first on the back of the extension of the pins. The pins are attached by means of Delrin bushings 58, 59 around which one end are free to rotate. The main body 57 is also free to rotate around its central axis. The main body 57 is axially held in place by means of a plastic retaining ring 63. The main body includes an internal diametrically magnetised magnet 65. The structure of the diametric magnet can be as illustrated in Fig. 3 having polar ends 21, 22. The diametric magnet 65 is permanently affixed to the main body 57 and rotates with the main body. The diametric magnet 65 takes up a particular positional arrangement in conjunction with diametric magnet 67, 68 which act as "spring" magnets to hold the diametric magnet in a particular rotational position around its axis in the absence of other magnetic fields. The arrangement can be such that the pins 52, 53 remain in a locked state. The effect being that the manhole cover remains locked. [0018] In order to activate the latch arrangement, the main body 57 needs to be caused to rotate so that the pins 52, 53 are withdrawn. This can be achieved through the utilisation of a magnetic switching device 14 which is brought into close contact with the magnet 65. Operationally, a non-Ferris cover 70 is provided having a slot 71 in which, when the latch is in use, a steel plate 72 is inserted in the slot 71. The steel plate 72 acts to reduce the external field associated with the magnet 65 and maintains the latch in the locked state. [0019] Initially, when it is desired to activate the latch, the magnetic switch 14 can be placed above the steel plate 72 and. activated thereby allowing for the removal of the steel plate 72. Next, the magnetic switching device 14 is placed in the slot 71 and again activated. The activation of the magnetic switching device 14 causes a repulsion effect of the diametric magnet 65 which rotates to overcome spring magnets 67, 68. The rotation of the magnet 65 causes the main body 57 to rotate and thereby causing the latching pin 52, 53 to move inwardly. As a result, the manhole cover 50 is released. [0020] One form of prototype implementation of the embodiment of Fig. 2 will now be described with reference to the photographic illustrations of Fig. 4 to Fig. 15. The photographic of Fig. 4 to Fig. 15 represent a prototype implementation of the embodiment of Fig. 2.

[0021] Turning initially to Fig. 4, there is illustrated a water valve cover having a latching device incorporated therein. [0022] Turning to Fig. 5, initially a magnetic switching arrangement such as that described in the aforementioned US patent is utilised to remove a top steel shunt or external field reducer placed centrally in the valve cover.

[0023] Next, as illustrated in Fig. 6, the shunt or external field reducer is removed illustrating the recess. The switching device is then placed in the recess and activated so as to activate the lower assembly and allowing for retraction of the pins and extraction of the cover.

[0024] Turning to Fig. 7, there is illustrated a photograph of the bottom surface of the removed cover. The pins being clearly illustrated.

[0025] Turning now to Fig. 8, there is illustrated a photograph of the pins that have been removed. The pins are attached with a Delrin bushing. [0026] Fig. 9 illustrates the main body after the removal of the pins. A plastic retaining ring is holding the main body in place. This ring can be made of Delrin and provides a low friction surface for which the main body can rotate freely on. It can be split to allow for easy assembly. Removal of the Delrin split ring reveals the side spring magnets. The spring magnets pro vide for appropriate positioning of the main body. Fig. 11 illustrates a photograph of the removed components.

[0027] Turning next to Fig. 12, there is illustrated the arrangement with the Delrin retaining split ring removed. The two blind holes illustrated provide holes for the positioning spring magnets. The spring magnets are used to keep the main body in a default position when non-activated by external magnetic forces.

[0028] Fig. 14 illustrates the main body in more detail. And Fig. 15 illustrates the chamber with the main body removed. The chamber can be mounted to the cover from the underside. This will eliminate any physical access from outside the cover. The chamber can be made out of aluminium or other suitable non-Ferrous material. [0029] According to the teachings of the preferred embodiment, other arrangements are possible. For example, a single pin or latch can be provided rather than the dual pin arrangement of Fig. 2.

[0030] A further alternate arrangement will now be described initially with reference to Fig. 16 wherein an exploded perspective view of the alternative embodiment 80 is illustrated. In this embodiment, the central body 81 is designed to fit within recess formed on mounting plate 82 and is clamped by clamping plate 83. The central body 81 includes internal magnets. Affixed thereto is cover 84 and lever arm 85 which is attached to the central body 81 by means of screws 86, 87. The screws 88, 89 affix the plate 83 to the plate 82 thereby retaining central body 81 therein whilst it is free to rotate. Fig. 17 illustrates an assembled side perspective view of the arrangement 80 and Fig. 18 illustrates a top plan view of the arrangement 80 in an assembled form. [0031] In Fig. 19, there is illustrated a topside perspective view of the retaining plate 83 which includes cavities for insertion of "spring magnets" 91, 92 which operate to hold the main body 81 in a predetermined position. The arrangement of Fig. 16 — Fig. 19 operates in a similar manner to that before described when mounted on a manhole cover or the like and can be activated and deactivated on demand. [0032] Fig. 20 to Fig. 25 illustrates photos of a prototype constructed in accordance with the teachings of this alternative embodiment, hi Fig. 20, there is illustrated a top view of a manhole cover having two magnetic latching mechanisms constructed in accordance with the teaching of the alternative embodiment. Fig. 21 illustrates the manhole cover removed with the two latching mechanisms 210, 211 clearly seen. Fig. 22 illustrates a close up view of one of the latching mechanisms in a first engaging position and Fig. 23 illustrates a further view of the latching mechanism in a non- engaging position.

[0033] Fig. 24 is an alternative view of the latching mechanism in an engaging position and Fig. 25 is a similar view of the latching in a disengaged position. [0034] It will be evident to the skilled artesian that the preferred embodiment provides for a simplified form of magnetic latching mechanisms that can be simply constructed and simply activated and deactivated whilst providing a degree of security from tampering by a third party.

[0035] The present invention can be utilised for other forms of access panels. Indeed the use can be for any access panel requirements. For example, the invention could be utilised in concealed latch panel access mechanisms. [0036] In a further modified embodiment, the surface 71 can be of a predetermined shape so that it only mates with a corresponding key shape. [0037] It will be further evident to those skilled in the art that the preferred embodiments can be set up to operate in a locking or unlocking mode depending on the placement of the magnets 67, 68 and the interaction of the key magnets relative to the main unit 57. Additionally, although the preferred embodiment have been described with reference to a repulsive force being set up between the key 14 and the unit 57, it will be evident to the skilled person that an attractive force could be alternatively utilised. The attractive force can be operated to either lock or unlock the latch in the presence of a key. Further, other arrangements of biasing magnets are possible. For example, a soft annular ferromagnetic member many be utilised instead. [0038] Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

THE CLAIMS DEFINING THE INTENTION ARE AS FOLLOWS:-

1. A magnetic latching arrangement comprising: a first surface; a first substantially cylindrical magnetically active unit having a distal and proximal end with said distal end being located adjacent one side of said first surface, said unit being located in a predetermined axial rotation by means of a resilient biasing force; a latching bolt attached to said substantially cylindrical magnetically active unit; wherein upon placement of a second predetermined magnetic field adjacent a second side of said first surface near the distal end of said unit, said unit is caused to rotate around an axis thereby causing at least one end of said latching bolt to undergo a translation from a first spatial position to a second spatial position.

2. An arrangement as claimed in any previous claim wherein said resilient biasing force is provided by magnetic interaction between the unit and at least one biasing magnet placed adjacent said magnetically active unit.

3. An arrangement as claimed in claim 2 wherein the number of biasing magnets is two.

4. An arrangement as claimed in any previous claim wherein the latching bolt is rotationally mounted to the distal end of said unit and said end is translated radially relative to the axis of said unit upon rotation of said unit.

5. An arrangement as claimed in any previous claim wherein said unit includes a diametrically magnetised magnet substantially adjacent the proximal end of said unit.

6. An arrangement as claimed in claim 5 wherein said second predetermined magnetic field is formed from a second diametrically magnetised magnet having a controllable magnetic force, placed adjacent a second side of said surface and, upon activation of the controllable magnetic force, said unit and said second diametrically magnetised magnet clamp said surface in between.

7. A magnetic latching arrangement as claimed in claim 6 wherein said first surface includes a predetermined profile and the second diametrically magnetised magnet includes a mating profiled surface which mates with the first predetermined profile upon activation of the latch.

8. A magnetic latching arrangement as claimed in any previous claim wherein the latching arrangement is utilised to lock or unlock a planar panel.

9. An arrangement as claimed in any previous claim wherein said resilient biasing force is provided by magnetic interaction between the unit and at least one soft ferromagnetic member placed adjacent said magnetically active unit.

10. A magnetic latching arrangement as claimed in claim 6 wherein said second diametrically magnetised magnet includes a handle grip for utilisation upon clamping to move the first surface.

11. A magnetic latching arrangement as claimed in any previous claim wherein the unit experiences an attractive force relative to the second predetermined magnetic field.

12. A magnetic latching arrangement as claimed in any previous claim wherein the unit experiences a repulsive force relative to the second predetermined magnetic field.

13. A magnetic latching arrangement substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.