US3860277A - Latching assembly with magnetic locking - Google Patents

Abstract

A latching assembly for a door swingable toward and away from a doorjamb or the like between a closed and an open position, comprising a pair of latch members mounted on the door and jamb, respectively, and relatively movable between an engaged latching position and a disengaged unlatched position. Each latch member includes one or more latching surfaces engageable with a latching surface on the other latch member when in the latched position preventing movement of said door relative to said doorjamb. Permanent magnet holding means is provided for holding or locking said latching members in said latched position, and selectively controlled electromagnetic means is used for producing a magnetic unlocking force with a polarity opposing that of said permanent magnet means for unlocking and relatively moving said latching members out of said latched engagement when said door is to be opened.

Description

1*Jan. 14, 1975 LATCHING ASSEMBLY WITH MAGNETIC LOCKING [75] Inventor: William S. Wang, Marina Del Rey,

Calif.

[73] Assignee: Consolidated Controls Corporation,

Bethel, Conn.

[21] Appl. No.2 225,598

Related U.S. Application Data [63] Continuation of Ser. No. 3,132, Jan. 15, 1970, Pat.

[52] U.S. Cl 292/251.5, 292/201 [51] Int. Cl. E05c 19/16 [58] Field of Search 292/201, 252, 261, 299,

[56] References Cited UNITED STATESPATENTS 9/1923 Englund 292/15 5/1944 Duby 335/290 2/1952 Manting 292/251.5

2,888,290 5/1959 Pierce 292/25l.5 3,312,492 4/1967 Remhof.... 292/201 1123,636 3/1953 Mark 292/25l.5 X

Primary Examiner-Richard E. Moore Attorney, Agent, or FirmPhilip C. Peterson [57] ABSTRACT A latching assembly for a door swingable toward and away from a doorjamb or the like between a closed and an open position, comprising a pair of latch members mounted on the door and jamb, respectively, and relatively movable between an engaged latching position and a disengaged unlatched position. Each latch member includes one or more latching surfaces engageable with a latching surface on the other latch member when in the latched position preventing movement of said door relative to said doorjamb. Permanent magnet holding means is provided for holding or locking said latching members in said latched position, and selectively controlled electromagnetic means is used for producing a magnetic unlocking force with a polarity opposing that of said permanent magnet means for unlocking and relatively moving said latching members out of said latched engagement when said door is to be opened.

13 Claims, 13 Drawing Figures PATENTED 14MB 3. 860.277

sum 2 OF 2 MW IT :90 18 188 W LATCHING ASSEMBLY WITH MAGNETIC LOCKING This is a continuation of application Ser. No. 3,132, filed Jan. 15, 1970, now US. Pat. No. 3,658,370, issued Jan. 25, 1972.

The present invention relates to a new and improved magnetic latching assembly, and more particularly to a latching assembly wherein magnetic forces are used to hold or lock a pair of mechanically engageable latch members in latched engagement.

The magnetic latching assembly of the present invention is particularly well suited for application in modern aircraft for latching doors or closure panels on compartments containing oxygen equipment and masks and other emergency supplies for the passengers. In this specific application it is desirable that the latching as sembly be hidden or generally unaccessible to the passenger and preferably mounted on the inside of the door or closure member within the compartment which contains the oxygen mask. Normally, unlatching is accomplished by electrical means actuated by the pilot of the aircraft; in addition, however, means must be provided whereby a passenger, with proper instruction, can manually unlatch the latch assembly from outside of the compartment so that in cases of emergency, when the normal electrical unlatching system fails, the door can be opened and fast access can be had to the emergency oxygen equipment inside the compartment.

The latching assembly of the invention is arranged so that the latching or holding means, which holds and maintains the door in a closed or shut position, is not dependent on magnetic force but instead holding forces are established by a positive mechanical latching engagement between one or more latching surfaces on a pair of cooperating latch members and thus the latch ing assembly is able to withstand considerable G loading, such as might be caused by rapid aircraft acceleration and deceleration or by other forces, such as prying or hammering on the door by a passenger. The latching assembly of the present invention is normally unlatched by a controlled electrical impulse delivered at the desirerd time, and the energy of the impulse may also be used to aid in opening the door.

The previously described features are objects of the present invention, and it is another object of the invention to provide a new and improved door latching assembly in which permanent magnet means is used to provide a holding or locking force for retaining a pair of latching members in positive mechanical latched engagement.

Another object of the invention is to provide a latching assembly of the character described wherein unlocking of the engaged latch members out of latched position is accomplished by electromagnetic means developing a force in opposition to the holding force of said permanent magnet means.

Another object of the present invention is to provide a new and improved door latching assembly of the character described using electromagnetic force for unlocking the latch members, which force is also effective to aid in opening the door with which the latching assembly is used.

Another object of the present invention is to provide a new and improved latching assembly which is completely hidden within a compartment on the inside of an access door thereof, yet which may be latched or unlatched from outside of the compartment by means of a tool or finger inserted through a slot or opening in the door or compartment wall.

Another object of the invention is to provide a new and improved latching assembly of the character described including means for visually indicating when the latching assembly is in an unlatched position, even though the door is still closed.

Another object of the invention is to provide a new and improved latching assembly of the character described wherein mechanical latching or holding force is attained with spherical latching surfaces.

Another object of the invention is to provide a new and improved latching assembly of the character described wherein one of the latch members includes a spheroid mounted adjacent the free outer end of a deflectable support member.

Another object of the invention is to provide a new and improved latching assembly described in the preceding object including an opposite latching member comprising socket forming means for receiving said spheroid and including a plurality of spheroids therein in annular ringlike array for movement radially inwardly and outwardly into and out of latching engagement.

Another object of the invention is to provide a new and improved latching assembly of the character described which is reliable and simple in operation, low in cost, and which can be mass produced in volume yet meet stringent safety test requirements.

Briefly, the foregoing and other important objects and advantages of the present invention are accomplished by providing a new and improved latching assembly having a pair of latch members mounted on a door and doorjamb, respectively, and movable relatively between an engaged, latched position and disengaged, unlatched position. Permanent magnet holding or locking means is provided for normally maintaining the latch members in an engaged latch condition, and electromagnet means is provided for momentarily opposing and nullifying the magnetic holdingforce with a force of opposing polarity for moving the latch members to an unlatched position, permitting the door to be opened.

In one embodiment, the latching members comprise a spheroid mounted adjacent the free, outer end of a flexible support rod and the spheroid is movable into and out of engagement with socket forming means comprising a plurality of spheroids in annular ringlike array movable radially inward and outward into and out of latching and unlatched engagement with the spheroid on said flexible rod.

For a better understanding of the present invention, reference should be had to the following detailed description taken in conjunction with the claims and drawings, in which:

FIG. 1 is a side elevational view of a typical aircraft seat including a compartment mounted in the back portion of the seat for containing emergency oxygen equipment for the passengers on the aircraft;

FIG. 2 is an enlarged fragmentary sectional view taken on a vertical plane through the aircraft seat of FIG. 1 showing the compartment and closure door thereof in enlarged detail with one embodiment of a door latching assembly constructed in accordance with the features of the present invention;

FIG. 3 is a sectional view showing the latching assembly as seen in the direction of arrows 3-3 of FIG. 2;

FIG. 4 is an elevational view of a compartment door on the rear of the aircraft seat;

FIG. 5 is a cross-sectional view taken substantially along line 55 of FIG. 3;

FIG. 6 is a cross-sectional view similar to FIG. 3 and illustrating a tool or implement being extended through an opening in the door for manually unlatching the latching assembly;

FIG. 7 is a view similar to FIG. 6 and illustrating a tool inserted through an opening in the door for manually latching the latching assembly;

FIG. 8 is an enlarged vertical sectional view similar to FIG. 2 showing another embodiment of a latching assembly constructed in accordance with the features of the present invention;

FIG. 9 is a rear elevational view of the seat compartment of FIG. 8 as seen in the direction of arrows 99;

FIG. 10 is a fragmentary vertical sectional view similar to FIG. 8 but illustrating the latching assembly in an unlatched position and the compartment door in a partially open position;

FIG. 11 is a transverse sectional view taken substantially along line 11-11 of FIG. 8;

FIG. 12 is a transverse sectional view similar to FIG. 11 taken substantially along line 1212 of FIG. 10; and

FIG. 13 is a vertical sectional view of yet another embodiment of a latching assembly constructed in accordance with the features of the present invention and employing a modified manual unlatching system.

Referring now more particularly to the drwings, in FIG. 1 is illustrated atypical aircraft seat 10 having a base orseat 12 permanently attached to thefloor 14 of an aircraft or other vehicle and anupstanding back portion 16 with anupper head rest 16a. Theupstanding back portion 16 is pivotally mounted on the seat por-.

tion 12 for angular adjustment to provide for comfort of the passengers in the aircraft. In order to provide oxygen and other equipment for the passengers in case of an emergency, an enclosure orcompartment 26 is mounted in theback portion 16 of theseat 10, and the compartment is adapted to contain an oxygen mask and other necessary emergency equipment as needed or required. Thecompartment 26 includes a pair ofvertical sidewalls 11, abottom wall 13, a rear orback wall 15, and atop wall 17, theforward edge portion 24 of which forms a jamb for adoor 30. Thedoor 30 is normally closed so that the interior of thecompartment 26 is not accessible to the passengers except in an emergency. The door is hinged to thebottom wall 13 of the compartment and is pivotable from a closed position (solid lines, FIGS. 2, 6, 7, 8, and 13) to an open position (dotted lines FIGS. 1, 2, and 10).

In accordance with the present invention, in FIGS. 2 through 7 is illustrated one embodiment of a new and improvedlatching mechanism 20 comprising afirst latching subassembly 22 mounted on the inside surface of thecompartment top wall 17 adjacent the forward edge ordoorjamb 24 and a second latching subassembly 28 mounted adjacent the upper edge on the inside surface of thecompartment door 30. Thelatching subassembly 22 includes abase 32 preferably stamped from sheet metal and provided with severalelongated slots 34 for receivingsheet metal screws 38 or other suitable fasteners used for securing the subassembly in place on the compartmenttop wall 17. The base includes a pair of upstanding, spaced apart,parallel flanges 40 having circular openings therein to receive and support the opposite ends of anelongated pivot pin 42 on which pin is pivotally mounted aU-shaped latching lever 44.

As viewed in FIGS. 2, 6, and 7, the right-hand leg 44a of theU-shaped latching lever 44 is supported by thepin 42, and the bight or middle portion orleg 44!) of the lever is movable between a generally horizontal, latched position (FIGS. 2 and 6) and an unlatched position (dotted lines in FIG. 2 and in FIG. 7). Thelefthand leg 440 of the U-shaped latch lever forms a latching dog adapted to mechanically engage aslot 46a formed adjacent the free outer end of alatch lever 46 of thesecond latching subassembly 28. Thelatch lever 46 is mounted on apivot pin 48 carried on asupport bracket 50 having abase portion 52 secured to the inside surface of thecompartment door 30. Thebracket 50 includes a pair of upstanding flanges 54 (FIG. 3) through which thepivot pin 48 extends and thelatch lever 46 is disposed to pivot between the flanges between a generally horizontal, latched position (FIGS. 2, 6 and 7) and a downwardly deflected, unlatched position (dotted lines FIG. 2) out of engagement with thelatching leg 440 of thelatch member 44. Thelever 46 is biased to pivot in a clockwise direction (arrow A in FIG. 2) about thepivot pin 48 by acoil spring assembly 56 so that upon disengagement with thelatching leg 440 of theU-shaped latch member 44, thelever 46 will automatically pivot to the unlatched position. In this position, the free outer end of the lever projects outwardly beyond the outer face of the door 30 (dotted lines FIG. 2) through a keyhole shapedslot 30a (FIG. 4) and provides a visual indication that thelatching mechanism 20 is in the unlatched position (even if thedoor 30 remains in the closed or upright position).

In accordance with the present invention, the latch levers 44 and 46 are held or locked in mechanically latched engagement with the upper end of thelatching leg 440 in theslot 46a by means of magnetic force which is supplied from permanent magnet means mounted on thebight portion 44b of theU-shaped latch lever 44. As best shown in FIG. 5, the permanent magnet holding force is established by abar magnet 60 and a pair of North and South, L-shapedpole pieces 62 and 64 which are attached by anonmagnetic rivet 66 to thelatch lever 44. The L-shapedpole pieces 62 and 64 are formed of soft iron material which is readily magnetized, and each includes an elongated leg in contact with one face of thebar magnet 60 which is sandwiched between the legs. The outer end faces of the short legs of thepole pieces 62 and 64 lie on a common plane and are adapted to contact opposite end portions of a platelike softiron core member 68 which is secured to thebase member 32 by a pair ofnonmagnetic rivets 72, or the like.

As shown in FIG. 5, thepole piece 62 is magnetized by thepermanent magnet 60 and becomes a north pole having a pole face labeled N which is attracted to the adjacent surface of the core 68, which also becomes magnetized by the influence of thepermanent magnet 60. Thepole piece 64 becomes a south pole having a pole face labeled S which is mutually attracted to thecore 68 and a completed magnetic circuit is thus provided to hold and maintain or lock thelevers 44 and 46 (which may be constructed of nonmagnetic material) in mechanically latched engagement against the biasing force of thespring 56 which exerts force tending to pivot thelever 46 into the unlatched position. The magnetic attraction between theplatelike core member 68 and therespective pole pieces 62 and 64 set up by thepermanent magnet 60 is sufficient to overcome the unlatching force exerted by thespring 56, and is also of sufficient strength to overcome the force of gravity acting on the latch levers as well as normal inertial forces developed because of acceleration and deceleration of the aircraft. It is significant to note that an opening pull exerted on the upper edge of thedoor 30 in the direction of the arrow B in FIG. 1 is resisted by the mechanical engagement between the latchinglevers 44 and 46 and is not dependent on magnetic holding forces. Moreover, because there is no requirement for the latch levers 44 and 46 to be made of magnetic or magnetizable materials, a wide range of suitable materials can be used to provide the needed strength. The magnetic flux path between thepermanent magnet 60 andcore 68 does not pass through the body of thelatch lever 44 and is entirely independent thereof.

In order to manually latch or unlatch themechanism 20, a thinknifelike tool 74 having acurved finger 74a projecting outwardly of the forward end (FIG. 70 is inserted through theslot 30a in thedoor 30. As thetool 74 is thrust inwardly in the direction of the arrow C, thelatch lever 46 is pivoted in a counterclockwise direction from the unlatched position (dotted lines FIG. 2) to the latched or horizontal position of FIG. 7, and simultaneously the upper curved surface of thefinger 74a of the tool engages a forward projection 44d on thelatch lever 44 and pivots the lever in a clockwise direction until latched engagement is established between the upper end of thelatch leg 44c and theslot 46a. As thelatch lever 44 is pivoted in clockwise fashion from the unlatched position to the latched position (FIG. 7, dotted lines), an attractive magnetic force develops between thepole pieces 62 and 64 and thecore 68. This force helps to move thelever 44 into the latched position and thereafter maintains or magnetically locks thelevers 44 and 46 in latched engagement. Thefinger 74a of the tool can also be used to unlatch the system by placing the finger on top of the projection 44d and pivoting thetool 44 in a clockwise fashion until the magnetic attraction between thepole pieces 62 and 64 and the core '68 is no longer sufficient to hold the levers together against the force of thespring 56. In this case, when thetool 74 is withdrawn from theslot 30a, thespring 56 acts to move thelever 46 to the unlatched position (dotted lines FIG. 2). In order that a pencil or other available implement can be used for manual latching or unlatching in case of an emergency, theslot 30a in the door includes an enlarged rounded portion 30b (FIG. 5) to accommodate a pencil, screwdriver, or other implement 76. The forward face of thelatching leg 44c above the projection 44d is formed with an indentation Me to receive the end of the implement for manipulating thelatch lever 44 into or out of latched engagement. TheU-shaped latch lever 44 is formed with a pivot stop or pivot limiting heel 44f on the upper end of theleg 44a. Engagement of the heel 44fagainst the base 32 (FIG. 7) limits the downward travel of theforward latching leg 440 to the position shown and thus permits ready engagement of thetool 74 or other im plement for latching the assembly.

In accordance with the present invention, automatic unlatching of the latchingsystem 20 to permit access to the interior of thecompartment 26 by the passengers is normally effected by electrical means, such as a switch or the like, operated by the pilot in the cockpit.

For this purpose, an electromagnetic coil winding is mounted on thecore 68 and thebase 32 is formed with anenlarged slot 32a in order to accommodate the winding. The coil winding comprises a relatively large number of turns wound onto the core so as to provide a magnetic polarity opposite that of the permanent when this occurs thelatch member 44 is pivoted about thepin 42 in a counterclockwise direction from the latched position to the unlatched position releasing thelatch lever 46 so that the door may be opened. As long as the coil winding 80 is energized, the system cannot be relatched; however, as soon as the coil is deenergized thesoft iron core 68 may again be attracted by the magnetism of thepole pieces 62 and 64 under the influence of thepermanent magnet 60, and relatching is readily accomplished with thetool 74 or other implement.

The latchingsystem 20 provides a reliable, safe system which is normally unlatched by electrical energy and which provides positive mechanical engagement to hold the compartment door closed. The latched engagement is maintained by permanent magnetic locking or holding forces which can be overcome either by electromagnetic forces in normal operation or in case of electrical failure the system can be unlatched manually. The latch system does not depend upon magnetic force for holding the compartment door in a closed position and, accordingly, can be used in a variety of different applications wherein greater, more positive mechanical latching strength is required.

Referring now to FIGS. 8-12, therein is illustrated another embodiment of a latching assembly with magnetic locking constructed in accordance with the features of the present invention and generally referred to by thereference numeral 120. The latching assembly includes afirst latching subassembly 122 which is mounted on thetop wall 17 of thecompartment 26 and asecond latching subassembly 128 which is mounted on the inside surface of thecompartment door 30 adjacent the upper edge.

The second latching subassembly comprises abase assembly 130 formed of aflat washer 132 secured to the inside surface of thedoor 30 by spot welding or suitable fasteners. Asecond washer 134 with with a raised central portion is secured to theflat washer 132 to provide a recess 136 (FIG. 8) in order to accommodate adisk 138 which is attached to the inner end of a support post orrod 140 which projects outwardly of the inside surface of thedoor 30 at substantially right angles thereto. The space orrecess 136 is larger than the space occupied by thedisk 138 and headed inner end of the support post orrod 140, and the raisedwasher 134 is provided with a central aperture slightly larger than the diameter of the rod to permit some free play or angular movement of the rod with respect to an axis or median line perpendicular to the door surface. The outer end of therod 140 is headed over against a spherical latch member orball 142 which is secured in place adjacent the free, outer end of the rod by the heading operation. In order to maintain the rod in a generally perpendicular attitude relative to thedoor 30, yet permit some free play or angular movement of the outer end of the rod within reasonable limitation, a stabilizingspring 144 is coaxially aligned on the rod adjacent the inner end portion thereof. Thespring 144 is formed with a plurality of helical convolutions which progressively decrease in diameter from a maximum adjacent thewasher base 134 to a minimum outwardly thereof on the body of the rod midway between the ends thereof. When thespherical latch member 142 at the outer end of therod 140 is deflected from the normal position wherein the rod is normal to thedoor 30, thespring 144 acts to restore or return the rod and ball to the normal or median position.

In accordance with the present invention, thefirst latching subassembly 122 includes a socketlike assembly generally indicated as 150 and adapted to receive and latchingly engage the single spherical ball orenlargement 142 on the free outer end of thesupport post 140 of the latchingsubassembly 128. Thesocketlike latching assembly 150 includes a cylindrical,hollow sleeve 152 open at both ends and having a radially inwardly extendedflange 154 at the forward end which provides a retaining ring at the forward end of the sleeve. A coaxially aligned, frustoconically shaped guide surface is provided on the forward face of theflange 154 in order to aid in axially centering thespherical latch member 142 as it is moved in an axial direction into the interior of thesocket assembly 150. Thecylindrical sleeve 152 is supported from a pair ofside flanges 156 disposed on opposite sides thereof and a pair of ribs 158 (FIG. 13) connect the sleeve to theflanges 156.

The rearward end of thesleeve 152 is partially closed by acap member 160 having a central aperture therein in order to accommodate the forward end portion of an elongated, axiallymovable latch plunger 162 having an enlargedforward end portion 164 which is mounted to slide within the sleeve. The rearward end portion of the latch plunger includes a reduceddiameter neck 162a and asleeve 167 is mounted adjacent the outer end of the neck to act as a grommet or bushing during reciprocal sliding movement of the plunger in a supportingaperture 170a formed in an upstandingrear flange 170 of a support bracket for thesubassembly 122. The enlargedforward end portion 164 of theslidable latch plunger 162 is movable between a forward or latched position as shown in FIGS. 8 and 11 to a rearward or unlatched position shown in FIGS. and 12 wherein latching engagement with theball 142 of the latchingsubassembly 128 is released. The latchingplunger 162 is biased toward the rearward or unlatched position by means of acoil spring 172 disposed between the rearend closure wall 160 on thesleeve 152 and a cross pin 174 (FIG. 8) extended transversely through the body of theplunger 162.

In accordance with the present invention, the enlargedforward end portion 164 of the latchingplunger 162 is formed with a deep axial recess orcounterbore 1640 which provides space for receiving and accommodating thespherical latch ball 142 of the latchingsubassembly 128 when the latchingsubassemblies 122 and 128 are in engaged latched position, as best shown in FIG. 8. A second, more shallow recess orcounterbore 164b of larger diameter is formed in theenlarged head portion 164 on theplunger 162, and a frustoconicalouter surface 1640 is formed to extend outwardly and forwardly of the second counterbore 1641).

In order to provide mechanical latching engagement for holding and retaining thespherical ball 142 in latched engagement with the latchingsubassembly 122, a plurality ofspherical latch balls 166 are mounted in circumferentially spaced array within thesleeve 152. Each of thelatch balls 166 is formed with a diametrically disposed drilledpassage 166a therethrough in order that a spring-steel C-ring 168 may be extended or threaded therethrough. The C-ring 168 is constructed of spring wire and has a nominal diameter when unstressed, as shown in FIG. 12, which diameter is considerably larger than its diameter in a compressed or stressed condition, as shown in FIG. 11. When theenlarged head portion 164 of the latchingplunger 162 is moved into the forward or latched position (FIG. 8), the latchingballs 166 are forced by thefrustoconical surface 1640 into thecounterbore 164b, which is smaller in diameter than the interior bore of thesleeve 152. When this occurs, theballs 166 are moved radially inwardly and the C-ring 168 is compressed to provide latching engagement between the ring ofballs 166 ofsubassembly 122 and thesingle ball latch 142 of the latchingsubassembly 128. In this condition, a low friction mechanical latched engagement is established between the spherical ball surfaces for holding thedoor 30 in the closed position.

In order to unlatch the latchingassembly 120, theplunger 162 is moved rearwardly to the unlatched position as shown in FIG. 10, and theenlarged head portion 164 is shifted to the rear end of thesleeve 152. When this occurs, any outward pull on theball 142 and expansion of the C-spring 168 to its normal unstressed position moves theballs 166 radially outwardly and out of engagement with thesingle latch ball 142, as shown in FIG. 12. When this occurs, thedoor 30 may be freely opened and pivoted to provide immediate access to the interior of thecompartment 26. Latching mechanical engagement between the latchingsubassemblies 122 and 128 is maintained by tangential contact between the spherical surfaces of thesingle ball 142 of the latchingsubassembly 128 and a plurality ofballs 166 contained in thesocket forming sleeve 152 of the latchingsubassembly 122. Because of this arrangement, exactly accurate alignment between thesubassemblies 122 and 128 is not a necessity and close manufacturing tolerances of the individual assemblies are not required. The mechanical holding ability of the latchingassembly 120, however, is not impaired even though close tolerances are not required.

Thespring 172 biases thelatch plunger 162 to the rear or the unlatched position and, in accordance with the present invention, the plunger is normally main tained in the forward or latched position by means of apermanent magnet member 176 which is sandwiched between the longer legs, respectively, of a pair of L- shaped north andsouth pole pieces 178 and 180 as best shown in FIG. 13. The pole pieces are made of soft iron which is readily magnetized by thepermanent magnet 176 and the permanent magnet and the pole pieces are mounted as a unit on a nonmagnetic sleeve orgrommet 181 which is carried on the reduceddiameter neck portion 162a at the rear end of the plunger 162 (FIG. 8).

As shown in FIG. 13, thenorth pole piece 178 includes a short leg having an end face in a common plane, with the end face of the short leg of thesouth pole piece 180. The aligned end faces of the respective north and south pole pieces are adapted to contact and exert magnetic attraction on a pair of fixedpole members 182 and 184 (FIG. 13), respectively, which are mounted at opposite ends of a flat core member 186 (FIG. 8) of anelectromagnetic coil 190.Rivets 188 or other suitable fastening means (FIGS. 8 and 13) are provided to secure thecore 186 and thepole pieces 182 and 184 together. These members are formed of soft iron or other material which is readily magnetizable but does not retain permanent magnetism to any extent.

The coil winding 190 and circuitry connected thereto are polarized so that when electric current is supplied to the coil thepole piece 182 becomes a north pole andpole piece 184 becomes a south pole. With this polarity, theelectromagnetize pole pieces 182 and 184 and the permanentmagnet pole pieces 178 and 180 repel each other causing theplunger 162 to shift to the rear and unlatch the mechanism.

When no current is supplied to theelectromagnetic coil 190, thecore 186 andpole pieces 182 and 184 are magnetized by thepermanent magnet 176 acting through the L-shapedpole members 178 and 180. Attractive forces are developed betweenpole members 182 and 184 and thepole pieces 178 and 180 so that a completed series magnetic holding circuit is established through themembers 176, 178, 180, 182, 184, and 186 for holding thelatch plunger 162 in the forward or latched position against the force of thebias spring 172. It should be remembered, however, that it is the mechanical latching engagement between theball 142 and ring ofballs 166 which provides the mechanical latching for holding thedoor 130 in the closed position, and this mechanical force is many times greater than the magnetic holding or locking force between the pairs ofpole pieces 178 and 180 and 182 and 184. The latchingassembly 120 thus provides a system having mechanical latching with magnetic locking or holding for maintaining the latch assembly in the engaged or latched position.

In normal operation, when it is desired to unlatch theassembly 120 so that thedoor 30 can be opened, electric current is supplied to the coil winding 190 causing thecore 186 to be magnetized and thepole pieces 182 and 184 to become electromgnetized as north and south poles, respectively. When this occurs, magnetic repelling forces are developed between the pairs ofpoles 182 and 178 and thepairs 184 and 180. These repelling forcesovercome or replace the permanent magnet holding force and shift theplunger 162 andhead portion 164 rearwardly within the socket orsleeve 152 from the latched position of FIG. 8 to the unlatched position shown in FIG. 10. When this occurs, the ring or array of latchingballs 166 is free to shift radially outwardly as the C-shapedspring 168 expands. Latching engagement between theballs 166 and thesingle latch ball 142 of the latchingsubassembly 128 is then released, permitting thedoor 30 to be opened freely, as shown in FIG. 10. Because of the socket and ball latching arrangement, close alignment between the latchingsubassemblies 122 and 128 is not a necessity because the frustoconical guide surface on the forward face of theflange 154 of the socket guidies theball 142 and support stem into axial alignment with thesocket sleeve 152 as the door is closed. After the door has been closed and theball 142 is centered with thedeep counterbores 164a and 164b in thehead portion 164, thelatch plunger 162 is shifted forwardly against the force of thebias spring 172 until the attractive magnetic forces developed by thepermanent magnet 176 between thepole pieces 178 and and theadjacent pole members 182 and 184 are sufficient to hold and retain the flanges in latched engagement as shown in FIG. 8. This attractive retaining force is large enough to overcome the biasing force of thespring 172 and the force of thespring 168, and as thehead portion 164 shifts forwardly in thesleeve 152 theballs 166 are cammed inwardly by theconical surface 1640 into thecounterbore 164b. The surface of the counterbore l64b acts as a containment surface preventing radially outward travel of theballs 166. Theballs 166 are thus maintained in contact against theball 142 and prevent thedoor 30 from being opened.

Manual unlatching of theassembly 120 is accomplished by apull ring 192 accessible through anopening 15a in therear wall 15 ofcompartment 26. Thepull ring 192 is pivotally connected to thesleeve 167 on the rear end of thelatch plunger 162 and is readily grasped by the finger and moved rearwardly to mechanically unlatch the assembly when desired, or if the electrical system fails. By manually moving thepole pieces 178 and 180 far enough rearwardly to diminish the magnetic attractive force between these pole pieces and theircounterparts 182 and 184, the force of thespring 172 is then available to hold theplunger 162 in the unlatched position until it is relatched. When it is desired to relatch thelatching system 120, thedoor 30 is closed so that therod 140 andball 142 of the latchingsubassembly 128 is positioned in centered alignment in thesocket sleeve 152. Theplunger 162 is moved forwardly against the bias of thespring 172 until themagnetic pole pieces 178 and 180, which are magnetized by thepermanent magnet 176, exert sufficient magnetic attraction on thepole members 182 and 184 todrawthe plunger 162 forwardly into the latched position. The latchingassembly 120 is maintained in the latched position of FIG. 8 until it is unlatched either by electromagnetic energy supplied by energizing the coil or by manually moving theplunger 162 rearwardly as by pulling on thering 192. The latchingassembly 120 thus provides a low cost, extremely reliable latching system for use with an aircraft oxygen compartment.

Referring now to FIG. '13, a different type of manual unlatching mechanism is provided, which includes an L-shapedlever 196 pivotally mounted on apin 198. One leg of the lever is attached to thepin 174 on theplunger 162 and the forwardly extending leg of the lever terminates approximately even with the front face of thedoor 30. The forward end of the forward leg of thelever 196 is accessible through anopening 30a formed in thedoor 30 so that the lever maay be moved to manually unlatch or latch the latchingassembly 120.

Although the present invention has been described with reference to several illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

What is claimed as new and desired to be secured by letters Patent of the United States is:

l. A latching assembly for a door swingable toward and away from a doorjamb, said latching assembly comprising a pair of mechanically engageable latch means mounted on said door and jamb, respectively, and movable relatively between an engaged, latched position and a disengaged, unlatched position, permanent magnet means for retaining mechanically latched engagement between said pair of said latch means in said latched position, electromagnet means having a polarity while energized opposing said permanent mag net means for overcoming the retaining force thereof permitting relative movement between said pair of said latch means to said unlatched position so that said door can be opened, one of said pair of said latch means including a pair of relatively movable members, said permanent magnet means mounted on one of said members and said electromagnet means mounted on the other of said members.

2. The latch assembly ofclaim 1 wherein said holding force exerted by said permanent magnet means extends in a direction generally normal to the direction of movement of said door toward and away from said doorjamb.

3. The latch assembly ofclaim 1 wherein one of said latch members is mounted for pivotal movement relative to the other, said permanent magnet means providing magnetic force for normally biasing said pivotally mounted latch member toward said latched position to engage said other latch means until said force is overcome by opposing magnetic force developed by energization of said electromagnet means.

4. The latch assembly ofclaim 3 wherein said pivotally mounted latch member includes stop means engageable with said other member for limiting the pivotal movement away from said latched position.

5. The latch assembly ofclaim 1 wherein the other of said latch means includes an elongated stem supported at one end in cantilever fashion and an enlargement mounted adjacent the outer free end of said stem for latching engagement with said one latch means in said latched position.

6. The latch assembly ofclaim 5 wherein said enlargement comprises a spherical ball mounted on said stem, said stem being laterally flexible adjacent said outer free end and movable axially relative to said one latch means into and out of latching engagement therewith.

7. The latch assembly of claim 6 wherein said one latch means comprises socket forming means including a plurality of circumferentially spaced latching balls movable radially of the axis of said stem into and out of latching engagement with said enlargement on said stem and means for moving said balls into and out of latching engagement with said enlargement.

8. The latching assembly of claim 7 wherein said one latch means includes a hollow sleeve for containing said balls and an elongated plunger mounted for axial sliding movement relative to said sleeve permitting radial movement of said balls in response to the axial position thereof, said permanent magnet means normally urging said plunger into an axial position wherein said balls are in said latched position.

9. The latching assembly of claim 8 wherein the force exerted by said electromagnet means while energized is active to move said plunger into a second axial position permitting said balls to move radially outward out of latched engagement with said enlargement.

10. The latch assembly ofclaim 9 wherein magnetic force attraction between said permanent magnet means and said latch means is in a direction generally parallel of said plunger.

11. The latching assembly ofclaim 1 including manually actuated means for moving said one member against the holding force of said permanent magnet means toward said unlatched position.

12. The latching assembly ofclaim 1 including manually actuated unlatching means acting on said one member of said one pair of latch means carrying said permanent magnet means for moving said one member relative to the other member of said pair toward said unlatched position.

13. The latch assembly ofclaim 1 including spring means for biasing said one latch means away from said latched position.

Claims (13)

1. A latching assembly for a door swingable toward and away from a doorjamb, said latching assembly comprising a pair of mechanically engageable latch means mounted on said door and jamb, respectively, and movable relatively between an engaged, latched position and a disengaged, unlatched position, permanent magnet means for retaining mechanically latched engagement between said pair of said latch means in said latched position, electromagnet means having a polarity while energized opposing said permanent magnet means for overcoming the retaining force thereof permitting relative movement between said pair of said latch means to said unlatched position so that said door can be opened, one of said pair of said latch means including a pair of relatively movable members, said permanent magnet means mounted on one of said members and said electromagnet means mounted on the other of said members.

2. The latch assembly of claim 1 wherein said holding force exerted by said permanent magnet means extends in a direction generally normal to the direction of movement of said door toward and away from said doorjamb.

3. The latch assembly of claim 1 wherein one of said latch members is mounted for pivotal movement relative to the other, said permanent magnet means providing magnetic force for normally biasing said pivotally mounted latch member toward said latched position to engage said other latch means until said force is overcome by opposing magnetic force developed by energization of said electromagnet means.

4. The latch assembly of claim 3 wherein said pivotally mounted latch member includes stop means engageable with said other member for limiting the pivotal movement away from said latched position.

5. The latch assembly of claim 1 wherein the other of said latch means includes an elongated stem supported at one end in cantilever fashion and an enlargement mounted adjacent the outer free end of said stem for latching engagement with said one latch means in said latched position.

6. The latch assembly of claim 5 wherein said enlargement comprises a spherical ball mounted on said stem, said stem being laterally flexible adjacent said outer free end and movable axially relative to said one latch means into and out of latching engagement therewith.

7. The latch assembly of claim 6 wherein said one latch means comprises socket forming means including a plurality of circumferentially spaced latching balls movable radially of the axis of said stem into and out of latching engagement with said enlargement on said stem and means for moving said balls into and out of latching engagement with said enlargement.

8. The latching assembly of claim 7 wherein said one latch means includes a hollow sleeve for containing said balls and an elongated plunger mounted for axial sliding movement relative to said sleeve permitting radial movement of said balls in response to the axial position thereof, said permanent magnet means normally urging said plunger into an axial position wherein said balls are in said latched position.

9. The latching assembly of claim 8 wherein the force exerted by said electromagnet means while energized is active to move said plunger into a second axial position permitting said balls to move radially outward out of latched engagement with said enlargement.

10. The latch assembly of claim 9 wherein magnetic force attraction between said permanent magnet means and said latch means is in a direction generally parallel of said plunger.

11. The latching assembly of claim 1 including manually actuated means for moving said one member against the holding force of said permanent magnet means toward said unlatched position.

12. The latching assembly of claim 1 including manually actuated unlatching means acting on said one member of said one pair of latch means carrying said permanent magnet means for moving said one member relative to the other member of said pair toward said unlatched position.

13. The latch assembly of claim 1 including spring means for biasing said one latch means away from said latched position.

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