US3312808A - Mechanically latched contactor - Google Patents

Description

April 4, 1967 w. F. DEHN 3,312,808

MECHANICALLY LATCHED CONTACTOR Filed March 17, 1965 4 Sheets-Sheet l agg e0 35 56 34? 4@ l' E; INVENTOR l: 50 @Z 5545 WILLIAM F. DEHN J |31 54 Y 56 47 57 jiu: 57

av (7 (i 40 4 35 April 4, 1967 w. F. DEHN 3,312,808

MECHANICALLY LATCHED -CONTACTOR Filed Match 17, 1965 v 4 Sheets-Sheet 2 INVENTOR WILLIAM F. DEI-4N BY e.

Filed March 17, 1965 April 4 v1967 w. F. DEHN y 3,312,808

MECHANICALLY LATCHED CONTACTOR 4vSheets-'Sheet 5 ZSQ 57 INVENTOR WILLIAM F. DEHN April 4, 1967 w. F. DEHN 3,312,808

MECHANI CALLY LATCHED CONTACTOR Filed March 17, 1965 4 Sheets-Sheet 4 325 325 53/ 338 55733 338 335 55o y 33o 337 34 342 345 356 l 5+ 354 324 342 52' M336 3Go 554 336 3 @s se? 3% 35e@ 35 +9 3&7 364 s@ 30, 5 3545 305 50( 304 320 3 530242) 32 5/5 321 2, :21 3oz v 3 58 5/3 als @f5 3l@ VON X 340 E Ex( a 35 54s s E 3 554 33e lNvl-:NTOR

WILLIAM F. DEHN I 365 3&2 34. 3.676a Bv 3@ @und $567 30/ l @s 1 5@ United States Patent C 3,312,808 MECHANICALLY LATCHED CNTACTOR William F. Dehn, Wauwatosa, Wis., assignor to Allen- Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Filed Mar. 17, 1965, Ser. No. 440,573 Claims. y(Cl. 200-169) This invention is related to an improved mechanical latch for mechanically holding or locking electrical switching devices, e.g. switches, relays, con-tactors, etc., in a desired contact open or contact closed position in response, `for example, to an external force or energization of a magnetic coil therein. The parti-cular control circuitry used for coil energization is a matter of choice to include, but not limited to, two-wire control.

-While the concept of mechanically latching electrical switch devices within the scope of this invention has been investigated by others, each known latch is complex, unreliable and/or unpredictable. The present invention avoids each of these disadvantages and thus satisfies the longstanding need for -a simple, efiicient and reliable mechanical latch.

The advantages of a mechanical latch are most evident when considering an electrically actuated switch or contactor which is to remain in its actuated position for a period of time. Through mechanical latching a magnet coil of the switch is energized only when it is desired to open or cl-ose the switch contacts with necessary latch action; thereby eliminating the possibility of noise originating in the initiating circuit, overheating of the initiating circuit, etc. Lighting circuits, especially night lighting, serve as good examples for application of the invention.

One object of the invention is to provide a simple -and effective mechanical latch for electrical switch devices with two moving elements which are maintained in abutting relation by a spring; one element which locks into a holding structure and is simultaneously primed for unlocking.

A more specific object is to provide the above described mechanical latch wherein a single spring connecting the latch and latch actuator is used to bias the latch toward a locking position when required and yet toward an unlocked position when locked.

A further object is to provide a simple mechanical latch with a minimum of moving parts which results in more reliable and longer use.

Another object is to provide a mechanical 'latch which is compact and easily adaptable to electrical switch devices of all descriptions.

Another object is t-o provide a most eicient mechanical latch with a minimum of moving parts and minimum surface contact.

A still further object is to provide a more economical latch for electrical switch devices, particularly in view of the latch simplicity,

A still further object is to provide a simple mechanical latch for -an electromagnetic device which can accommodate any desired control circuit to include two-wire control actuated by means of a simple single pole switching means.

Other objects of the invention are and will become apparent from the specification herein.

FIG. l is a front, cutaway view of a latch embodiment of this invention in combination with an electromagnetic device represented by a contactor shown in an inactive or normal operating position.

FIG. 2 shows a side view of the latch yand contactor combination taken along line 2 2 of FIG. 1.

FIG. 3 shows an enlarged fragmentary view of FIG. l

after the magnet coil has -been energized, thus lifting ythe armature, contact carrier and attached latch to a position above the mechanical latch locking position; and further showing line -contact between the latch lock detent and the beveled catch surface.

FIG. 4 shows an enl-arged fragmentary view of FIG. l with the latch cammed to its holding position after the coil has been deenergized.

FIG. 5 shows an enlarged fragmentary view of a combination similar to FIG. l, viz. a contactor in combination with a second latch embodiment of the invention, the combinati-on shown in the same position as FIG. 1 and taken along line 5-5 of FIG. 8.

FIG. 6 shows the combination of FIG. 5 after coil energization and consequential rise of armature contact carrier and attached latch to a position of line contact Abetween the latch lock detent and the beveled catch surface comparable to FIG. 1.

FIG. 7 shows the combination of FIG. 5 in the latch locking position after the coil has been de-energized comparable to FIG. 4.

FIG. 8 shows a side view of the combination of FIG. 5 taken along line 8 8 of FIG. 5.

FIG. 9 shows an enlarged fragmentary view of a cornbin-ation similar to FIG. l including a still further latch embodiment with a portion of a contactor in an inactive or normal operating position comparable to FIGS. l and 5.

FIG. l0 shows the combination of FIG. 9 after coil energization and consequential rising of the armature, contact carrier and attached latch to a position comparable to FIGS. 3 and 6. K

FIG. ll shows the the combination of FIG. 9 after coil de-energization with the latch in its locking position, i.e., the latch lock detent in surface contact with the beveled catch surface.

FIG. 12 shows a side view of FIG` 9 as taken along line 12-12 of FIG.,9.

FIG. 13 shows a cross-sectional, fragmentary view of the mechanical latch feature of this invention used with an electrical switch.

FIG. 14 shows a cross-sectional, fragmentary view of the combination in FIG. 13, but with the switch mechanism having been tripped by downward movement of the switch actuator and the latch mechanism having .been moved to a position where line contact exists between the latch and latch catch surface.

FIG. 15 shows a partial cross-sectional, vfragmentary view of the latch in FIG. 13 as the latch would appear in its latched or locked position.

FIG. 16 shows a fragmentary, cross-section, side view of the mechanical latch in combination with the switch as shown in FIG. 13. .l

While only three embodiments ofthe latch mechanism feature of the present invention are shown in the drawings, the invention is not intended to be limited in scope to these embodiments. Moreover, the invention is not limited to a particular electric switch device,v let alone a particular electromagnetic device, although the drawings illustrate a specific contactor and switch. Fin-ally, the number of mechanical latch assemblies used with a switch is a matter of choice to one skilled in the art, eg., only one latch assembly, properly located with respect to operating balance would be sutlicient in the case of the contactor combination shown in FIGS. 1-l2.

Turning to the drawings, the electromagnetic device, depicted here as a contactor, will be described by means of its basic elements since only the fundamental operation of the contactor is necessary to understand its relationship to the latch assembly. Referring to FIGS. 1 and 2 a mounting plate 1 is attached to the frame 2 and forwardly extending arms 3 and legs 4, which support the operating portions of the contactor. Contact carrier 5 slidably supported by the forwardly extending when magnet coil 14 is energized.

' -The slidable carrier 5 moves between two extreme positions with the first or lower extreme position occurring during inactivity of the magnet coil 14, i.e., a nor- -mal operating position (see FIG. l), while the second position or upper extreme position occurs when the magnet coil 14 has been energized and laminated magnet armature 12 abuts xed laminated yoke 13. It should be noted that this lower extreme position is limited by Contact carrier abutting forwardly extending leg 4 (FIG. 1). Somewhere between these two extreme positions, the movable contacts 15 and 16which are secured to the contact carrier 5 by conducting Spanner 17, abut stationary contacts 18 and 19 which are conductively attached to terminals 20 by means of contact elements 21. The terminals have clamping screws 22 so as to hold line wires (not shown) attached thereto. Compression springs 25 located in contact cages 6 abut the conducting Spanner 17 on its underside (the spanner also being located within the contact cages 6) so that upward movement of the contact carrier 5 is permitted after movable contacts 15 and 16 have abutted stationary contacts 18 and 19, i.c., spanner 17 compresses spring 25 after the contacts are closed. Deenergization of magnet coil 14, whether immediately upon abutting contact of the armature 12 and fixed yoke 13 or a controlled time thereafter, will interrupt the magnetic field which results in separation of the armature 12 from fixed yoke 13 and consequential downward movement of the contact carrier 5. Additional features of the `contacter shown in the drawings include arc chamber 26, arc chamber cover 27, molded cover 28 and auxiliary switch 29' with its actuating tongue 30.

The latch assembly 35, of which two are shown in FIG. l, is fundamentally made up of three elements, viz. latch 36, latch actuator 37 plus outer and inner fixed latch guides 38 and 39, respectively. These guides are part of a wrap-around casing 4G for the latch assembly 35 which is attached to forwardly extending legs 4 at 41. Latch actuator 37 is attached to the contact carrier 5 by means of connecting element 42, mounting ears 43 and bolts 44 to provide simultaneous movement therewith; while concave cam surface 45 of the .latch actuator 37 contacts latch 36 for movement thereof. Connecting elements 42 also include holding plate 46 which limits downward motion of the contact carrier by abutment of the latch 36 in its locking position (see FIG. 4), although it should be noted that various expedients can beused to limit this downward motion including spring 25.l.-' ;.The latch 36, itself, consists of a free end 47 abutting the cam surface 45 of the actuator 37, a latch lock detent 48 and a protrusion 49 which includes reset surface 50 engageable with a bottom surface 54 of window 55, blanked from outer latch guide 38. The shape of the latch 36 is signifiy cant for two reasons: (1) to permit pivoting about the catch 56, i.e. thelatch center of gravity isV preferably located outside of the latch mass above the catch, and (2) the latch lock detent 48 should permit line contact with the catch 56 before the latch 36 pivots about the catch, i.e. when the latch is biased toward the inner latch guide 39 `(sce FIG. 3). Obviously, the latch shape must permit y desired movement thereof. f

l Connecting latch 36 and latch actuator 37 are tension spring 57 mounted on pins 58 and 59 which are respectively attached to the latch and latch actuator (see FIG. 2). The wrap-around casing provides-surfaces for both holding the latch in its locking position, i.e. the beveled catch surface 60 of catch 56, and for resetting the latch 36 after unlocking, i.e. bottom surface 54 in window 55 `which abuts reset surface of protrusion 49. Y

The operation of the structure shown in FIGS. 1 thru 4 is as follows: When the contactor rests in the normal, inactive position of FIG. 1, the contact carrier 5 is in its lower extreme position as Iare the movable latch assembly parts (36 and 37) due to direct connection the-rebetween, viz. connecting element 42 and mounting ears 43. Upon energizing the fixed, magnet coil, the movable, laminated magnet armature 12 moves toward the fixed, laminated yoke 13 carrying with it the Contact carrier 5 and movable latch assembly parts. While electrical and mechanical contact between movable contacts 15 and 16 and stationary contacts 18 and 19 is made during the armature movement toward the yoke 13, the upward movement continues toward yoke abutment by virtue of the fact that movable contacts 15 and 16 are spring supported. Near or at the upper limit of arm-aturemovemcnt, i.e. the extreme upper position, the latch locking detent 48 rises above the catch 56 of the inner latch guide 39 as shown in FIG. 3, whereupon the bias of the tension spring 57 pulls the latch against the inner latch guide 39. The contact carrier 5 may continue on to an upper extreme position (not shown) although the contactor can be so designed that the upper extreme position is achieved when the -latch 36 first contacts the inner latch guidel39, (FIG. 3).

At this point in the locking sequence, the circuit through the movable contacts 15 and 16 and stationary contacts 18 and 19 is complete as the energized magnet coil 14 holds the magnet armature 12 and fixed yoke 13 in abutting relationship, However, by the use of the mechanical latch feature of this invention, the -magnet coil circuit may be deenergized without interrupting the electrical connection through the line contacts 15, 16 and 18, 19, c g. by the control of a two-wire coil circuit. To accomplish this end, the current through the coil 14 is interrupted causing the contact carrier 5 and its attached latch actuator 37 to move downwardly (see FIGS. 3 and 4), This downward movement brings the latch lock detent 48 and inner guide catch 56 into line contact (if such contact is nonexistent) as shown at 62 in FIG. 3; while further downward movement of the latch actuator 37 results in separation of ror reduced abutting pressure between the latch free end 47 and the actuator 37. vLatch free end 47 is therefore free to move toward the inner guide 39 as the latch center of gravity causes the latch to pivot on beveled catch surface until surface contact is made between the latch lock detent 48 and beveled catch surface 60 of catch 56 (see FIG. 4). Further movement of the magnet armature 12 and contact carrier 5, after coil deenergization, is limited by holding plate 46 which abuts latch 36 in its locking position as shown in FIG. 4. Whether the latch free end 47 abuts the cam surface 45 when the latch is in a locked position is a matter of design.

In the locked position, the tension spring 57 biases the upper `part of latch 36 away from the inner guide 39 while the surface cont-act between latch lock detent 48 and beveled catch surface 60 along with holding plate 46 hold the latch in the locked position shown in FIG. 4.

When it is desired to interrupt the contacts 15, 16 and 18, 19, magnet coil 14 is `again energized so as to lift the contact carrier 5 along with the moving parts of the latch assembly 36 and 37 to their upper position thereby separating the latch lock detent 48 from`the beveled catch surface 60. Due to the spring bias of latch 36 away from the inner guide 39, said separation results in immediate movement of the latch lock detent 48 and the upper portion of latch 36 down and away from the inner guide 39 as latch 36 pivots about the latch free end 47. Subsequent deenergization of magnet coil 14 will interrupt the magnetic field so as to cause the armature and moving latch assembly parts to move downward to the position shown in FIG. l. During this downward movement, the reset surface 58 of latch protrusion 49 abuts the bottom surface 54 of window 55 in the outer latch guide 38 which causes-the upper portion of the latch 36y to abut the inner latch guide 39 and thereby bias said portion toward said guide by moving the latch free end 47 to a position between the inner and outer guides. In this position the latch lock and unlock cycle has been-completed such that energization of magnet coil 14 will cause upward movement of the armature and latch assembly.

FIGS. -8 show another embodiment of the latch assembly 135 which is similarly associated with an electromagnetic device, here again shown as a contractor, in the manner of FIGS. 1-4. The contactor is represented by contact carrier 105, movable contact 115 and fixed contact 118 plus contact compression spring 125. Structurally, this latch assembly embodiment differs -only in the particular latch actuator 137 which is narrower than the distance between inner latch guide 139 `and outer latch guide 13S plus the fact that said actuator is pivoted on the mounting pin 159 and has a concave cam surface 145 tending toward a V-shape. The remainingv parts of the latch assembly are substantially the same as those in FIGS. 1 through 4 and have been correspondingly indicated by reference numerals in the 100 series.

In operation the sequence is the same as that outlined for FIGS. 1-4, i.e. FIGS. 5-7 correspond respectively to FIGS. 1 and 3-4 in regard to the position of the armature (not shown), contact carrier 105 and latch 136. The pivoted latch actuator 137 rides against the outer latch guide 138 during the upward movement of the contact carrier 105 and during a part of the relatively short downward movement when the coil circuit is interrupted. After the latch lock detent 148 and the inner latch 1guide catch surface 139 abut in line conta-ct at 162 (see FIG. 6), the latch actuator continues downwardly a distance permitted by tension spring 157. This distance is sufficient to separate or release pressure contact between the latch 136 and latch actuator 137 so as to permit pivoting of latch 136 about catch 156 with free end 147 moving toward the inner guide 139; and at the same time pivoting the latch actuator 137 to the inner guide 139 by free end 147 contact with the side walls of the concave cam surface 145'. In this position (FIG. 7) the tension spring 157 biases the latch away from the inner latch guide 139. The downward movement of the contact carrier 105 is stopped by a holding plate 146 abutting the top of latch 136 in its locked position (FIG. 7), although it is again noted that various other expedients can be used to limit such downward movement'. Unlocking includes the same Vsequence as out-lined in the operation of FIGS. 14, viz. lifting of the latch 136 to permit latch pivoting about free end 147 and away from the inner guide 139, followed by resetting of the latch during lowering of latch 136 and contact carrier 105 to the position of FIG. 5.

FIGS. 9-12 depict the third latch embodiment and illustrate further the use of the forwardly extending legs 204 as the beveled catch surface 260 for latch lock detent 24S. The combination of contactor and latch assembly is basically the same as that illustrated by FIGS. 1-4 and simil ar .parts have been referred to by corresponding reference numerals in a 200 series.

The principal difference injlatch assembly structure of this embodiment is to be found in the latch actuator cam surface 245 which is raised near a point intermediate the outer latch guide 238 and forwardly extending leg 204 along with the latch structure at free end 247 which permits movement from one side of the latch actuator 237 to the other. Attention is called to the fact that the actuator is Vsubstantially as wide as the distance between outer latch guide 238 and the extended leg support 204.

In operation, the sequence is substantially similar to that of the previous embodiments with FIGS. 9-11 showing latch assembly position corresponding to those of FIGS. 1 and 3-4. Specifically, latch 236 is moved upwardly by latch actuator 237 until the latch lock detent 248 rises above the beveled catch surface 260 of extended leg 204 (FIG. After the coil current is interrupted and line contact is established at 262 (FIG. lO), the latch downward direction 236 pivots about catch 256 as latch actuator 237 moves away from latch 236 permitting free latch end 247 to move toward extended leg 204 and over the hump of the actuator cam surface 245. Again, final downward movement of the contact carrier 205 ends when the holding plate 246 abuts latch 236 in its locked position (see FIG. l1), although other expedients may be used to limit this movement, e.g. tension spring .257.

The release of latch 236 is similar -to that of FIGS. 1-4 in that the latch actuator 237 is raised to separate the latch detent 24S from beveled surface 260 at which time the bias of tension spring 257 causes -the latch to pivot away from the extended leg 204 about latch free end 247. Downward movement of the latch 236 results in resetting the latch as latch protrusion 249 engages the bottom surface 254 of window 255 in outer latch guide 238.

Another possibie use for the present invention is with a switch, e.g. the snap-acting switch illustrated by FIGS. 13-16. Here, an external force activates the snap switch while the mechanical latch feature permits removal of this external force without the normal return of the switch to its original position.

The particular switch in FIGS. 13-16 is basically that switch shown in U.S. Patent No. 2,796,487; and accordingly, this description will only include those features of the switch necessary for understanding of the mechanical latch feature.

An enclosure 301 provides the outer protection for housing 302 in which snap action mechanism 303 is located. This ymechanism 303 includes a vertically moving plunger 304 which slides through an aperture 305 of housing 302 to abut actuator p-oint 306. The lower end of plunger 304 abuts, and thereby transfers motion to, U-shaped, resilient toggle or contact carrier 307. Carrier 307, in turn, includes a lower spring seat 308 which abuts biasing spring 309.

A resilient leaf 312 is hingedly secured to both ends of carrier 307 by means of carrier notches 313. This resilient leaf 312 includes movable contact blades 314 to which two pairs of oppositely mounted, movable contacts 315 and 316 are attached. Correspondingly, two pairs of lixed contacts 318 and 319 are located adjacent the movable contacts 315 and 316 along with respective contact terminals 320 and terminal screws 321.

Thus, the snap action mechanism 303 operates in the as plunger 304 is moved by actuator point 306 to thereby move carrier 307 until resilient leaf 312 is snapped from the downward bowedposition of FIG. 13 to the upward bowed position of FIG. 14. As is also evident from the FIGS. 13 and 14, biasing spring 309 will return the resilient leaf 312 to its downward bowed position when actuator point 306 is relieved of its motivating force.

An operating head 324 is located immediately above enclosure 301 for the purpose of housing an actuator for snap-action mechanism 303 in cavity 325. The upper end of cavity 325 is closed by main plunger 326 in combination with a seal 327 which is secured to the operating head 324 by means of a force lit between cover plate 328 and st-op plate 329. As will be seen from FIGS. 13 and 14, screws 329:1 are used to secure cover plate 328 to the operating head 324. The lower portion of lcavity 325 is filled in part by fixed, casing guide 330 and partially by the movable, latch assembly 335. Y

It should be noted at this point that although the particular mechanical latch embodiment to be used with the switch of FIGS, 13-16 is not limited to the embodiment illustrated, those parts of the mechanical latch assembly 335 which are common or similar throughout the figures will be designated hereafter by similar reference numerals differing only by the use of a 300 number series. Therefore, the latch is designated as 336 while the latch actua mechanical latch of the tor is indicated by reference numeral The principal difference to be found in the mechanical latch assembly 335'of FIGS. 13-16 is the casing 338 which serves as the housing for latch 336 and latch actuator 337. As will be apparent, this casing 338 is movable (being guided by fixed, casing guide 330) in the same manner as connecting elements 42 are movable in the previous figures. The latch actuator end of casing 338 is closed by end wall 339. Retaining wire 340, which is integral with main plunger 326, retains independent disk 340e within the cavity of main plunger 326 and consequently restrains the compressed, overtravel spring 341 which abuts said disk 340a. The gap between end wall 339 and disk 340a created by the particular location of retaining wire 340 (see FIG. 13) exists when a downward external force is not being applied to main plunger 326 to thereby enhance therlocking step depicted in FIG. which will be described later.

Compression spring 342 abuts flange 343 of main plunger 326 in order to locate this main plunger with respect to the latch assembly l335 as well as to aid biasing spring 309 in the return of snap action mechanism 363 (and consequently the latch assembly 335) from the position of FIG. 14 to the position of FIG. 13. It should be noted at this point, however, that operati-on of the snap action mechanism 303 may only require spring 341 (which would, itself, abut end wall 339) and biasing spring 309 thus eliminating the need for retaining wire 340, disk 340a `and return spring 342. Moreover, the particular shape of casing 338 may be other than that shown in the FIGS. 13-16, e.g. a cylindrical shape.

As is the case in the previously described structure, the latch actuator 337 has a cammed surface 345 which abuts the free end 347 of the latch 336. In addition, a holding pla-te 346-cut from the wall Iof casing 338 is located adjacent the latch lock detent 343 of latch 336 for abutment therewith as shown in FIG. l5. The location of holding plate 346 with respect to latch 336 must be such that the latch 336 will be permitted to move to the position of FIG. 14 and yet establish contact as shown in FIG. 1S.

Further similarity to previously described structure resides in the fact that latch 336 includes a protruding portion 349 including a reset sunface 350. This protr-usion 349 is again capable of extending externally from casing 338, viz. into cutout 353 of casing guide 330. With the return of the latch assembly from the position of FIG. 15 to the position of FIG. 13, it will be seen that reset surface 350 will abut the end 354 of cutout 353 for resetting purposes. Cutout 356 in casing `guide 330 is opposite from cutout 353 and receives latch lock detent 343 of latch 336; the cutout 356 including a beveled surface 360 against which detent 348 abuts for line contact at 361 as shown in FIG. 14 and for a lock position as shown in FIG. l5.

Finally, the latch 336 and latch actuator 337 are maintained in an operating relationship by Imeans of tension spring 357 which is secured to latch 336 by pin 358 and to latch actuator 337 by pin 359. This relationship is best shown in FIG. 16 which also illustrates the rfact that pin 359 locates latch actuator 337 with respect to the casing 338. Y

End wall 362 completes the Vcasing 338 at an end opposite Vfrom end wall 339. As is best seen in FIGS. 13 and 14, the motion transferred from casing 338 to snap action mechanism 303 is affected by rod 363, with flange 364, attached to end wall 362 by screw 365. Other means used to secure said rod 363 to said end wall 362 such as by riveting. Previously mentioned actuator point 366 is threadedly attached to rod 363 for abutment with the vertically moving plunger 304, while intermediate the lian-ge 364 and end Wall 362 circular diaphragm 366 is held in place by washers 367 and 368. This circular diaphragm 366 is secured to t-he enclosure d by groove 369 so that the lsnap action mechanism 303 is sealed from the operating head casing 304- for obvious reasons,

S eg. to maintain clean operating conditions in mechanisrn 303.

Because the operation of the mechanical latch as used in FIGS. 13-16 is similar to the operation of the latches previously outlined above, only a rbrief operational description of this particular latch combination is considered ne-cessary. Referring first t-o FIG. 13 Vand beginning with the switch in the position shown, an external downward force on Amain plunger 326 will result in downward movement of casing 338 as compression spring 341 forces disk 340e to abut casing end wall 339. Consequently, both latch actuator 337 (through pin 359) and actuator point 306 (through end wall 362 and rod 363) are moved. Suiiicient downward travell of motivated carrier 307 will cause resilient leaf 312 to bow upward thereby opening contacts 316 and 319 while closing contacts 315 and 318 as shown in FIG. 14. At some point during this downward motion, latch lock detent 34S of lat-oh 336 travels below beveled surface 360;`whereupon detent 348 is pivoted into the cutout portion 356 of cylinder 4guide 330 since the latch 336 is biased in that direction (see FIG. 14). As will be further noted from FIG. 14, the relationship between latch lock detent 348 and beveled catch surface 360 at this point is that of a line contact therebetween as indicated by reference nurneral 361. Depending upon the switch requirements, downward movement of the casing 338 may -or may not occur after latch lock detent 348 makes contact with beveled surface 360.

When the external force is removed from main plunger 326, a switch, such as that shown in FIGS. 13-l5 and which has not been equipped with the mechanical latch feature of this invention, would return to the position shown in FIG. 13. However, by means lof the invention described herein, the removal of external force from main plunger 326 `will not change the existing contact relationship, i.e. movable contacts 315 will remain in contact with fixed contacts 318. Specifically, latch 336 will pivot at the point of line contact 361 (ie. contact between `latch lock detent 348 and beveled catch surface 360) when the casing 338 and main plunger 326 are free to be moved upwardly by compression spring 309, aided by return spring 342, if available. It is apparent that during this pivoting period, latch 336 is fixed `with respect to casing guide 330 as opposed to lat-ch actuator 337 which may continue its rupward movement. In addition, the gap `between disk 340a and end wall 339 (the gap resulting from the removal of external force from main plunger 326) 4permits and encourages this Vupward movement of latch actuator 337 (and casing 338) while at the same time aiding the pivoting of latch 336 by reducing the pressure between 4latch 336 and latch actuator 337, i.e. only tension spring 357 provides pressure therebetween. As this pivoting of latch 336 continues, latch actuator 337 is rotated about pin 359 by latch free end 347 which moves along cammed surface 345 until latch actuator `337 abuts the detent side of casing guide 330 as shown in FIG. 15.

The net result of this pivoting by latch 336 and latch actuator 337, from the position orf FIG. 14 to that shown in FIG. 15 is a primed latch 336 which is biased away from the beveled catch surface 360. The latch assembly 335 is thereby locked `in this position by a surface to surface contact relationship between latch detent 348 and beveled catch surface 360 again shown in FIG. 15. In

this locked position, `spring 357 may be of suiiicient strength to prevent further upward movement of theV casing 338 and carrier 307 although additional locking may be provided by lholding plate 346. For example, the embodiment shown in FIG. 15 calls for contact between a holding plate 346 and latch 336 after the latch and latch actuator 337 have separated. This separation is encouraged by the gap, whic-h necessarily eliminates any lack of a restraining force from spring 341, between end wall 339 and disk 340e. It should be noted, however, that contact between latch 336 and latch actuator 337 may be maintained during this locked position while, at the same time, utilizing holding plate 346. F-or example, the holding plate 346 may Vbe caused to abut latch 336 While the latter remains in contact with latch actuator 337 by reshaping the latch 336. It is noted that this construction would require a force to `restrain the actuator 337 such as could be supplied by spring 341V to end wall 339. In turn, disk 340g could be thereby eliminated.

To unlatch the latch assembly 345 from the FIG. l position, an external downward force on main plunger 326, suicient only to separate the detent 348 from beveled end surface 360, is necessary since latch 336 is biased away from the beveled catch surface 360` during the latching. This slight downward force on main plunger 326 will cause the latch 336 to pivot away from the beveled catch surface 360 (about latch free end 347) and permit -compressed spring 309 to return the snap action mechanism 303 and the latch assembly 335 to the position shown in FIG. 13 (aided by return spring 342 if needed and used). During this unlatching sequence it is also necessary to reset the latch assembly 335; which resetting is accomplished as reset surface 350 on the protrusion 349 of latch 336 contacts the end abutment portion 354 of cutout 353 during the return of latch assembly 335 to the position of FIG. 13, i.e. the unlatched position.

Thus, it will be evident that the above-described invention provides a signicant improvement in an electromagnetic -device and mechanical latch combination by providing a more eicient, compact economical and extremely adaptable assembly.

I claim:

1. In ycombination with an electrical switch device including a movable switching means, a mechanical latch assembly comprising a latch actuator means mechanically associated with said movable switching means for movement therewith, independent latch means comprising lock means at one end and a free end abutting said actuator means for movement therewith, catch means adjacent said mechanical latch assembly for accommodating said lock means in a locking position, resilient means acting to lbias the lock means end of the latch means in a direction toward the catch means when said free end is away from said catch means and to bias said lock means end of the latch means away from said catch means when said free end is toward s-aid catch means.

2. In combination with an electrical switch device including a movable switching means, a mechanical latch assembly comprising a latch actuator means mechanically associated with said movable switching means for movement therewith, independent latch means comprising lock means at one end and a free end abutting said actuator means movement therewith, catch means ad-V jacent said mechanical latch assembly for accommodating said lock means in a locking position, resilient means to limit any separation between said actuator means and said latch means, said resilient means further acting to bias the lock means end of the latch means in a direction toward the catch means when said free end is away from said catch means and to bias said lock means end of the latch means away from said catch means when said free end is toward said catch means.

3. In combina-tion with an electrical switch device including a movable switching means, a mechanical latch assembly means comprising a latch actuator means mehancally associated with Said @lavable Switching mans for movement therewith and having a cam surface, independent latch'means comprising lock means at one end and a free end abutting said actuator means at said cam surface for movement therewith, catch means adjacent said movable switching means for accommodating said lock means in a locking position, said latch means and said actuator means each including pivotal means to which resilient means are connected so as to limit any separa-tion of said actuator means from said latch means while permitting movement of said free end toward said catch means during said separation, said resilient means further acting to bias the lock means end of the latch means end in a direction toward the catch means when said free end is away from said catch means and to bias said lock means end of the latch means away from said catch means when said free end is toward said catch means.

4. The combination of claim 1 in which said catch means accommodates said lock means only when said lock means end of the latch means is biased toward said catch means.

5. The combination of claim 1 including reset means to move the free end in a direction away from the catch means.

6. vThe combination of claim 1 wherein the lock means is adapted for line contact with said catch means.

7. The combination of claim 1 wherein the latch means has a center of gravity which encourages latch pivoting about said free end.

8. The combination of claim 1 including a holding means which restricts movement of said switching means when said catch means accommodates said lock means.

9. The combination of claim 8 wherein said holding means comprises a plate means which abuts said latch means when said catch means accommodates said lock means.

10. The combination of claim 1 wherein the lock means is adapted for line contact with said catch means and wherein holding means restrict movement of said switching means when said catch means accommodates said latch lock means.

11. The combination of claim 10 wherein said holding means comprises a plate means which abuts said latch means when said catch means accommodates said lock means.

12. The combination of claim 3 in which the cam surface of the actuator means is concave.

13. The combination of claim 3 in which the actuator means pivots about said pivotal means thereof in the plane of said free end movement.

14. The combination of claim 13 in which the actuator means cam surface is concave.

15. The combina-tion of claim 3 in which a disc means is interposed between said latch assembly and a resilient means through which a switch moving force is transferred whereby said -discY means abuts said latch assembly when said force is exerted.

References Cited bythe Examiner UNITED STATES PATENTS 2,749,415 6/1956 Davis 20o- 167 3,201,545 8/1965 Kruzie 335-170 3,244,836 4/1966 Myers 1 20o-16a ROBERT K. SCHAEFER, Primary vEaaminer. I-I. JONES, Assistant Examiner.A

Claims (1)

1. IN COMBINATION WITH AN ELECTRICAL SWITCH DEVICE INCLUDING A MOVABLE SWITCHING MEANS, A MECHANICAL LATCH ASSEMBLY COMPRISING A LATCH ACTUATOR MEANS MECHANICALLY ASSOCIATED WITH SAID MOVABLE SWITCHING MEANS FOR MOVEMENT THEREWITH, INDEPENDENT LATCH MEANS COMPRISING LOCK MEANS AT ONE END AND A FREE END ABUTTING SAID ACTUATOR MEANS FOR MOVEMENT THEREWITH, CATCH MEANS ADJACENT SAID MECHANICAL LATCH ASSEMBLY FOR ACCOMMODATING SAID LOCK MEANS IN A LOCKING POSITION, RESILIENT MEANS ACTING TO BIAS THE LOCK MEANS END OF THE LATCH MEANS IN A DIRECTION TOWARD THE CATCH MEANS WHEN SAID FREE END IS AWAY FROM SAID CATCH MEANS AND TO BIAS SAID LOCK MEANS END OF THE LATCH MEANS AWAY FROM SAID CATCH MEANS WHEN SAID FREE END IS TOWARD SAID CATCH MEANS.

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