WO1995016095A1

WO1995016095A1 - Magnetic latch

Info

Publication number: WO1995016095A1
Application number: PCT/US1993/011941
Authority: WO
Inventors: Robert D. Brady
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-12-08
Filing date: 1993-12-08
Publication date: 1995-06-15
Anticipated expiration: 1996-06-08
Also published as: AU6014394A

Abstract

A magnetic latch (10) comprises a latch arm (12) having pendulum legs (44) and mounted onto a bottom plate (16) for engaging a cabinet, door, door frame member, window, lid, or other enclosure (18, 19). A screw (20) or other fastening mechanism may be used to attach the bottom plate (16). A top plate (22) is provided having an adjustably positionable magnet (24) coupled thereto and having a retainer (26) for retaining and securing the latch arm (12) thereto. The magnet (24) is preferably of a substantially flat and elongated configuration. The top plate (22) is secured to a predetermined area distant from the bottom plate (16) preferably by a screw (28), adhesive, or other mechanical fastening mechanism.

Description

Magnetic Latch

Technical Field

This invention relates to magnetic safety latches, and more particularly to a disturbance responsive magnetic latch for mounting on cabinet doors, chests, windows, child play apparatuses, child proofing cabinets and other enclosures, and the like, and which is responsive to vibrations, shaking, and other disturbances such as those encountered in seismic events, moving vehicles, boats, and airplanes.

Background Art

Numerous latching devices have been proposed and implemented for securing cabinets, windows, and doors in a closed position. Such latching devices are set to be in either a locked or an unlocked position. As such, these devices do not provide for protection against sudden vibrations or movement caused by earthquakes or other seismic events. For example, conventional latches are often dislodged from their locked position and the contents scattered and in many cases destroyed during earthquakes and other seismic events.

Abrupt and sudden disturbances are also often encountered in vehicles such as airplanes, automobiles, motor homes, boats, and the like. In such situations conventional approaches to latching doors, windows, chests and the like, are often inadequate to protect against such disturbances, and particularly unpredictable disturbances, often with disastrous results. Furthermore, such latches, since they are either in an on or locked position at all times are not useful as a backup safety latch. Furthermore, two such devices may not be used in combination with each other in order to provide a backup or safety feature because either both will be in the locked position and thus interfering with normal usage of the doors, or if one is locked and the other left unlocked there is no backup or safety function achieved, and if both are left unlocked there is no protection whatever, and in fact the doors will remain open. A search of the prior art did not disclose any patents that read on the claims of the instant invention, however, the following U.S. Patents were considered related;

U.S. Patent No. 5,035,415 issued to Brady, July, 30, 1993 U.S. Patent No. 4,848,812 issued to Slaughter, July 18, 1989 U.S. Patent No. 4,452,475 issued to Bloch et al, June 5, 1984

U.S. Patent No. 3,844,597 issued to Elrod et al., October 29, 1974 U.S. Patent No. 3,635,511 issued to Waller, January 18, 1972 U.S. Patent No. 3,388,938 issued to Peterson, June 18, 1968 U.S. Patent No. 3,312,492 issued to Remhof, April 4, 1967 U.S. Patent No, 2,971,789 issued to Weaver, February 14, 1961

A prior patent issued to the present inventor, U.S. Pat. No. 5,035,451, disclosed a disturbance responsive magnetic latch including a latch arm with sping legs and preferably mounted to a planar mounting surface. A second mounting surface was provided having a magnet and a retainer attached thereto for securing the latch arm. Such disturbance responsive magnetic latch was a significant advance over prior latches.

The present invention provides improved latching, securing, and adjustment means allowing for greater reliability and broader applications.

Slaughter discloses a concealed safety lock having a magnetic bolt disposed within a throughbore of the device. This device was used in either an on or locked position or an open or unlocked position. No means were provided which could activate the locking mechanism by sudden motion or other disturbances and thus such device was severely limited in use and application as either a backup safety latch or as a latch responsive to sudden vibrations or other disturbances.

Bolch et al. show a door with a magnetic sealing strip as a latching device. Such device prevented the opening or unlatching of the door due to sudden motion, however, it was not activated by such motion and as such was, when activated, always in a locked position.

The Waller, Remhof, and Weaver patents all disclose latching devices of a genre where magnets are used to lock a latch in a closed position. None show a device which is activated or locked by sudden movements. Nor are any of these patents useful as a backup latch or as a safety latch

SUBSnTUTE SHEET (RULE 26) The remaining prior art disclose mechanical devices used to latch doors or lids shut and are included for illustration and are representative of the art to which this invention relates.

Accordingly, it is the primary object of this invention to provide a disturbance responsive latch which is activated by vertical or horizontal motion such as that encountered in earthquakes, moving vehicles, boats, and the like, which is easy to install, which is simply and easily adjusted, and which may be used in combination with conventional latches without interfering with their function or the normal opening and closing of a door, window, chest, or the like.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Disclosure of the Invention

To achieve the foregoing objects, and in accordance with the purposes of the invention as embodied and broadly described herein, a magnetic latch for selectively securing or opening a cabinet door, or other enclosure such as a window, chest, door, child proofing household articles, and the like is provided, comprising: a bottom plate for engaging a face of said cabinet door or other enclosure; latch means operably coupled to a pivot pin and having a pendulum leg integral therewith, said latch means being coupled to said bottom plate; means for securing said bottom plate to said cabinet door or other enclosure; a top plate having a magnet coupled thereto, said magnet having adjustment means secured thereto for adjustably positioning said magnet on said top plate; retainer means mounted on said top plate in a normally non-latching relationship with said latch means so that a disturbance or motion causes magnetic attraction to place the latch means in a position to engage the retainer means when the cabinet door or other enclosure is moved to open; and means for securing said top plate to said cabinet or other enclosure. The adjustment means preferably include means for optimally positioning of the magnet on the top plate in relation to the retainer means. The adjustment means also preferably includes means for maintaining a change in the positioning of the magnet during any disturbance to the cabinet, door, window, or other enclosure.

In accordance with the present invention there also is provided a motion responsive magnetic latch for selectively locking a cabinet door to a cabinet in response to movement of said cabinet door, comprising: a bottom plate for engaging a face of said cabinet door; a latch arm operably linked to a pivot pin and having a pendulum leg integral therewith, said latch arm being operably mounted to said bottom plate; means for securing said bottom plate to said cabinet door; a top plate secured to said cabinet and having an adjustably positionable magnet coupled thereto for attracting said latch arm; retainer means secured to said top plate for retaining said latch arm in a normally non-latching relationship between said latch and said retainer means so that a disturbance or motion causes magnetic attraction to place the latch arm in a position to engage the retainer means when the door is moved to open thereby limiting movement of said door in response to sudden or abrupt movements; and means for securing said top plate to said cabinet.

The present invention is a novel and improved latching device which is sensitive and responsive to vertical and horizontal shaking, rocking, or vibrational motion and activated by the same. The latch includes a latch arm operably secured to a pivot pin and secured to a bottom plate for engaging the door, door frame member, window, cabinet, or other enclosure member. Means are included for securing the bottom plate to the door. A top plate is provided having a magnet coupled thereto and having retainer means for retaining the latch arm thereto. The magnet may be pad shaped of a substantially flat and elongate configuration, or round, oval, or any other configuration corresponding to the design of the top and the bottom plate. Means are also provided for adjustably positioning the magnet on the top plate and maintaining the position of the magnet in a disturbance or sudden movement. Means are provided for securing said top plate to a cabinet or cabinet frame member.

The latch is typically mounted to the inside of the door or other enclosure, but may be mounted otherwise depending upon the application. The two mounting plates are operably spaced so that when the door is closed the latch arm is in a rearmost or unlatched position. If a sudden motion or disturbance occurs the door or other enclosure moves slightly towards an open position and the latch arm moves into the proximity of the magnet and into its magnetic field. The magnet is preferably positioned on the top plate by means of an adjustment wheel and pin operably secured to the magnet. The latch arm becomes firmly secured to the magnet, and as the door moves further open the latch arm slips into the retaining means and the door is prevented from opening further. The latch is very sensitive to horizontal motion traverse to the door, which is the critical direction of door movement during an earthquake, for example, as well as vertical motion due to shaking, rocking, or vibrational motion. Deactivation of the latch is accomplished by simply closing the door to a completely shut position.

Brief Description of Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a preferred embodiment of the invention and, together with a general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention.

FIG. 1 shows a side elevational view of a disturbance responsive magnetic latch, according to the invention.

FIG. 2 shows a side elevational view of such latch showing the latch arm secured by the retainer, according to the invention.

FIG. 3 shows a bottom perspective view of the retainer portion of such latch, according to the invention.

FIG. 4 shows a front perspective view of the latch arm portion of such latch, according to the invention.

Fig. 5 shows a schematic representation of such latch with pendulum legs and pivot point, according to the invention.

Best Mode for Carrying Out the Invention

Reference will now be made in detail to the present preferred embodiments of the invention as illustrated in the accompanying drawings.

In accordance with the present invention, there is provided a magnetic latch for selectively securing or opening a cabinet door or other enclosure, comprising: a bottom plate for engaging a face of said cabinet door or other enclosure; latch means operably coupled to a pivot pin and having a pendulum leg integral therewith, said latch means being coupled to said bottom plate; means for securing said bottom plate to said cabinet door or other enclosure; a top plate having a magnet coupled thereto, said magnet having adjustment means secured thereto for adjustably positioning said magnet on said top plate; retainer means mounted on said top plate in a normally non-latching relationship with said latch means so that a disturbance or motion causes magnetic attraction to place the latch means in a position to engage the retainer means when the door or other enclosure is moved to open; and means for securing said top plate to said cabinet door or other enclosure.

Fig. 1 shows a disturbance responsive magnetic latch 10 according to the preferred embodiment of the invention. The latch preferably comprises a latch arm 12 operably secured to pivot pin 30 by securing pin 30 in apertures in bottom plate 16 and securing latch arm 12 below pin 30 as shown in Fig. 4. The latch arm 12 is secured to a bottom plate 16, preferably with edge walls 40 forming channel 42 which is mounted onto a door or door frame member 18. Bottom plate 16 may be composed of any durable resilient material such as plastic, metal, composite, wood, or the like. Pivot pin 30 is housed in support shoulder 32 and is pivotally secured within walls 40 and may be integral or separate from latch arm 12. Mounting means for base plate 16 is preferably provided by screw 20, however, other conventional mechanical fastening means may also be used, such as bolts, adhesives, pins, and the like. Screw 20 is secured in adjustment slot 21. By varying the position of bottom plate 16 on door 18 and locking plate 16 into position by screw 20, thereby providing a means for precise and incremental adjustment of latch arm 12 is provided.

A top plate 22 having a magnet 24 coupled thereto and a retainer 26 with housing 38 operably secured thereon is mounted on to a cabinet or frame member 19 by screws 28 in apertures 23 or other conventional fastening means at a predetermined position separate from base plate 16. As shown in Fig. 2, latch arm 12 is secured by retainer 26 when latch arm 12 is moved or shaken by a disturbance and attracted to magnet 24 on the top plate 22. Top plate 22 may be composed of plastic, metal, composite, wood, or and durable resilient material. Magnet 24 is preferably adjustably mounted on top plate 22 by pin 36 which is adapted to receive and adjustably secure adjustment wheel 34. By rotation of adjustment wheel 34 the position of magnet 24 on top plate 22 can be positioned as desired and adjusted for increased sensitivity of latch 10 to disturbances. This is extremely convenient and useful for various applications such as cabinet doors, windows, child play apparatuses, doors, and the like.

Referring now to Fig. 3, top plate 22, magnet 24, and retainer 26 are shown detached from a door. Adjustment wheel 34 retainer 26 with housing 38 are shown according to one preferred embodiment of the invention. It is apparent that a wide variety of magnets differing in shape and magnetic strength may be used depending upon the application in which latch 10 is used. It is also apparent that top plate 22, housing 38, and retainer 26 may be configured in a wide variety of ways according to the teachings of the present invention. Furthermore, retainer 26 may be constructed in a variety of shapes and corresponding to different embodiments of the hooked end of latch arm 12. For example, housing 38 may be configured with curved walls, or retainer 26 may be configured as a shallow hook, a moderately pronounced hook, or a more sharply defined hook. Alternatively, retainer 26 may be shaped as a groove, clasp, or other retaining structure.

Bottom plate 16 is preferably configured in a substantially flat elongated configuration as is illustrated, detached from a door or door frame member, in Fig. 4. Walls 40 define channel 42 in which pivot pin 30 is secured which in turn pivotally supports latch arm 12. Latch arm 12 preferably includes pivot arm 14 made integral therewith. Latch arm 12 preferably is hooked at one end as shown in Fig. 4, however, it may be alternatively configured so long as it is adapted to be received and retained by retainer 26.

Top plates 22 and bottom plate 16 may, in alternative embodiments be secured to a door or door frame member by means of adhesives, or by a combination of screws and adhesives. Retainer 26 is preferably hooked at one end as illustrated in Fig. 3, but may, in an alternative embodiments, be replaced by a ratchet, nipple, shouldered pin, or equivalent latching means.

Preferably the disturbance responsive latch 10 is composed of a plastic such as a thermoplastic or similar durable material but may be otherwise. Latch 10 is preferably manufactured by injection molding, however, many alternative manufactures well known in the art may also be utilized. Referring now to Fig. 5, a schematic representation of the magnetic latch of the present invention is shown according to another embodiment of the invention, however, the principles illustrated in Fig. 5 correspond to the general principles of the present invention as embodied in the other embodiments described herein. The latch mechanism comprises a 2-arm pendulum 44 with upper arm 46 and lower arm 48 and pivot point 50. The center of gravity (CG) 52 of pendulum 44 lies on a point between the two arms as shown, where a line joining pivot point 50 and the CG from the angle 0, with the CG falling directly below the pivot point.

The gravitational force acting on the CG, which is equal to the mass M times the acceleration of gravity, is separated into two components, one acting along the line joining the CG and pivot point 50, and another which acts perpendicular to it. This second component of force (M x G)sin0, is what causes the pendulum to rotate. If 0 is large, then a large force is required to induce rotation of the pendulum. Conversely, if 0 is small, it takes relatively little force to induce rotation.

Placing upper arm 46 in close proximity to a magnet effectively shifts the location of the CG toward the right in Fig. 5, because the magnetic force acting upward on the upper arm counteracts the gravitational force acting downward on it. With the CG essentially beneath the pivot point, the angle 0 is significantly reduced, and the pendulum swings more freely than it would in the absence of the magnet. In order to have a balanced pendulum (ie., one with its CG beneath the pivot point) without the magnet, lower arm 48 would have to be significantly longer and/or more massive than arm 46. Since the length of the upper arm is constrained by the distance it must travel to engage and lock, its size cannot be reduced. Also, reducing the size of upper arm 46 would reduce its strength. Therefore, the only alternative would be to increase the size and weight of the lower arm. This, however, would reduce the sensitivity of the pendulum to high frequency type motions, such as those sometimes encountered in earthquakes. The magnet makes it possible to retain a compact size of the magnetic latch, while at the same time provide sufficient latch strength, and proper latch sensitivity to earthquake ground motion.

In operation and use bottom plate 16 attaches to a cabinet door or other hinged member, such as a window, child play apparatus, door, or other enclosure. In the event of a disturbance such as an earthquake or other seismic event which causes the cabinet or other enclosure to shake pendulum leg 14 will move up and down in accentuated vibration. That is, small vibrations from the earthquake or other disturbance will be accentuated by the pendulum leg 14 of latch 12 best seen in Fig. 4. The corresponding retainer 26 on top plate 22 is secured to the cabinet or other enclosure and when latch arm 12 is moved in an upward direction from the accentuated vibrations, it is attracted and secured by magnet 24 which will hold it in an imminent interlock position. If the door is moved further in the outward direction , the latch arm 12 will be retained by retainer 26 and the door will be held in place thereby preventing spillage of the contents of the cabinet. Magnet 24 also functions to hold and position latch arm 12 prior to engagement with retainer 26 in position for interlocking with retainer 26 and thereby prevents vibrations of the door or cabinet from pulling latch arm 12 away from its imminent interlock with retainer 26. Magnet 24 is positioned as desired on top plate 22 by adjusting adjustment wheel 34 on pin 36.

Deactivation of the latch is accomplished by simply depressing latch arm 12, or closing the door, window, or other enclosure to a full shut position. This will move the latch arm 12 past the zone of magnetic attraction and allow latch arm 12 to detach from retainer 26 and magnet 24 and return to its normal, or open, position.

While the above description contains many specificities, they should not be construed as imitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other possible variations are within its scope. For example the magnetic latch of the invention could include machine controlled or machine de-activated components, for example, responsive to off-balance vibrations or eccentric vibrations. The latch of this invention could also be applied in many different applications, for example, in recreational or marine vehicles, or in aeronautical apphcations. In such application the latch could be set to respond only to sudden, unexpected disturbances, such a when the vehicle or craft has been landed, moored, or parked. The latch may also be very conveniently used around a house for both active and passive child proofing various cabinets, chests, and other enclosures. The latch may be composed of alternative materials such as plastics or wood, and various configurations and designs, for example, one or more latch arms, may be successfully utilized for the base plate or hooking mechanisms. Those, skilled in the art will recognize that permutations of bottom plate 16 and top plate 22 will allow for attachment of disturbance responsive magnetic latch 10 to cabinets or enclosures 19 which are partially inset or fully inset doors. Adjustment wheel 34 allows for precise position of magnet 24 on top plate 22, allowing for sensitivity adjustments of latch 10 and adaptation and use of latch 10 in a wide variety of applications. Also different embodiments of top plate 22 will allow attachments of disturbance responsive magnetic latch 10 to the vertical side or horizontal top member of a cabinet , window, child play apparatus, or enclosure openings.

Therefore, additional advantages and modifications will readily occur to those

SlβSTTTUTE SHEET (RULE 26) skilled in the art. The invention in its broader aspects is, therefore, not limited to the specific details, representative apparatus and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

SUBSTΓΓUTE SHEET (RULE 26)

Claims

1. A magnetic latch for selectively securing or opening a cabinet door or other enclosure, comprising:

a bottom plate for engaging a face of said cabinet door or other enclosure;

latch means operably coupled to a pivot pin and having a pendulum leg integral therewith, said latch means being coupled to said bottom plate;

means for securing said bottom plate to said cabinet door or other enclosure;

a top plate having a magnet coupled thereto, said magnet having adjustment means secured thereto for adjustably positioning said magnet on said top plate;

retainer means mounted on said top plate in a normally non-latching relationship with said latch means so that a disturbance or motion causes magnetic attraction to place the latch means in a position to engage the retainer means when the door or other enclosure is moved to open; and

means for securing said top plate to said cabinet door or other enclosure.

2. The magnetic latch of claim 1 wherein said latch means comprises a latch arm.

3. The magnetic latch of claim 2 wherein said retainer means further includes a hook at one end thereof.

4. The magnetic latch of claim 1 wherein said means for securing said bottom plate comprises screws.

5. The magnetic latch of claim 1 wherein said means for securing said bottom plate comprises adhesives.

6. The magnetic latch of claim 1 wherein said adjustment means for adjustably positioning said magnet comprises an adjustment wheel operably coupled to a pin secured within the magnet.

7. The magnetic latch of claim 1 wherein said magnet is of a substantially flat configuration.

8. The magnetic latch of claim 1 wherein said retainer means comprises a hook shaped element.

9. The magnetic latch of claim 1 wherein said means for securing said top plate to said cabinet door or other enclosure comprises screws.

10. The magnetic latch of claim 1 wherein said means for securing said top plate to said cabinet door or other enclosure comprises adhesives.

1 1. A motion responsive magnetic latch for selectively locking a cabinet door to a cabinet in response to movement of said cabinet door, comprising:

a bottom plate for engaging a face of said cabinet door;

a latch arm operably linked to a pivot pin and having a pendulum leg integral therewith said latch arm being operably mounted to said bottom plate;

means for securing said bottom plate to said cabinet door;

a top plate secured to said cabinet and having an adjustably positionable magnet coupled thereto for attracting said latch arm;

retainer means secured to said top plate for retaining said latch arm in a normally non-latching relationship between said latch and said retainer means so that a disturbance or motion causes magnetic attraction to place the latch arm in a position to engage the retainer means when the door is moved to open thereby limiting movement of said door in response to sudden or abrupt movements; and

means for securing said top plate to said cabinet.

12. The motion responsive magnetic latch of claim 11 wherein said latch arm further includes a hook at one end thereof.

13. The motion responsive magnetic latch of claim 11 wherein said means for securing said bottom plate comprises screws.

14. The motion responsive magnetic latch of claim 11 wherein said means for securing said bottom plate comprises adhesives.

15. The motion responsive magnetic latch of claim 11 wherein said magnet is of a substantially flat elongate construction.

16. The motion responsive magnetic latch of claim 11 wherein said retainer means comprises a hook shaped element.

17. The motion responsive magnetic latch of claim 11 wherein said means for securing said top plate comprises screws.

18. The motion responsive magnetic latch of claim 11 wherein said means for securing said top plate comprises adhesives.

19. The motion responsive magnetic latch of claim 11 wherein said magnet is adjustably positionable by means of an adjustment wheel operably coupled to a pin secured to said magnet.

SIBST1TUTE SHEET (RULE 26)