US1286001A - Automatic switch. - Google Patents

Description

A. V/A H HOESCT ETL AUTOMATIC SWITCH.

APPLTQATTON FILED APR. 2. 1917.

l yT a 1: mum BOV. 6, 1918. 2 SHEETSQSHEU 1.

mfua'now. Henry H Gesch en, Wi H iam H Hoesc hen,

UMTED erariale sans ormone,

HENRY A. HOESCHEN AND `JVULINJI l-. HOESCHEN, OF OMAHA, NEBRASKA, ASSGNORS T BAKER ICE MACHINE COMEANY, OF OMAHA, NEBRASKA, A CORPORATION OF NEBRASKA.

AUTOMATIC SWITCH.

Specification of Letters Patent.

Patented Nov. 26, 1918.

automatically, to stop and start the motor or to stop and start the operation of other 'electrically-operated devices, in accordance with conditions which are varied by the operation of the motor or the like. Thus where an electric motor is employed to op crate a compressor for a refrigerant, it may be desirable to stop and start the motor au tomatically according to decreases anc in creases of temperature in a rei'rigerating chamber which is cooled by the compressed refrigerant. Themain switch provided by our invention is actuated by electromagnets or solenoids which are energized alternately by electrical ener supplied thereto by the closing of contro -circuits, the latter being eiiected by a thermostat or the like, and the control circuits being opened alternately by the movement of thejmain switch, after being closed for a suliicient time to cause operation of the main switch. lt is the object of our invention to provide various structural refinements in switches of the class set forth, including an improved torni of solenoid adapted to exert a uniform pull upon a core or armature having a relatively long stroke, improved contact forming means for the main switch by which burn ing of the conta-cts by arcing is reduced to a minimum, means for maintaining the con-` trol-circuit closed during amaximum pref portion of the period of operation ci' the main switch whereb, stopping ci the open ation at an internas iate or dead position is avoided, and means for locking the main switch both in open and closed positions so that the .saine .is movable vonly by energica tion of the' appropriate solenoid or electro magnet, eiected by the closing ci" the a spective ccontrol-cucnitu lin the accompanying drawings, lignre is a front View of a switch n hanism em l v l Y bodymg our invention a go t4 ed to engage the fiat races 21 on being in vertical section, and illustrative circuit connections being indicated diagrammatically, Fig. 2 is a vertical section through the axes of the actuating lever and the main switch arms, Figs. 3, l and 5 are detail front views showing diierent` posi- Vtions of the actuating lever relatively to the locking cam-slot, and Fig. 6 is a detail side View ci one of the solenoids.

ln thc illustrated embodiment of our iiiren 'm1, there is provided a suitable supi por ing plate or switchboard '7, preferably of insulating material and arranged in a vertical position. Near the center of said plate Y there an opening through which a stud S is passed as shown in Fig Q, said stud haring an inte "l cylindrical collar or the by a nut i0 screw; of. r? stud i iront the collar, he tion being threaded and shouldered, carrying a nut ll 7which holds washer l2 against the shoulder. @n the stud between the washer l2 and collar 9 there is pivotally mounted a hub 13 having integral unwardly extending arms le and l5 and a, downwardly extending arm ld The is le and 15 extend divergently "Iron-i the hub and near their spaced ends each carries a series of resilient contact-plates l?, which are secured to the arms by screws i9 insulated therefrom by plates 29 as sholi'n. lThe end-portions of the contactplates a curif'ed away `trom the arev ad;

of terminaleposts 2, Q3, :Ell and mounted on the plate l the shown. The faces 2l. each s terminal-posts are slim 1l;T i tively to. each other, 1 tact-plates are moved toward and from said faces the ends oi the plates will engage and disengage serially, the outer plates engaging tac-es first ben slightly' bent bosco. next comes into contact with the the outermost contac'oplates i8 carr i ends small blocks carbon and also make 21 as the a move at terninal-posts. inns. in brea cuits formed through said te posts and contacts, any resulting arcs will be formed between the blocks 26 and the posts, and burning of theplates 17 thereby avoid-A ed. The terminal- posts 22, 23, 24 and 25 are connected, respectively, with bindingposts 27, 2 29 and 30 arranged near the lower edge of the'plate 7, the connecting conductors being indicated in Fig. 1 by lines 31. The described parts constitute the main switch mechanism, and the circuit-closing and open-circuit positions thereof are shown by fullfand dotted lines, respectively, in Fig. 1. ,It may be noted that at a position intermediate the eXtreme positions just mentioned, the arms 14 and 15 are symmetrical to a vertical plane through the axis of the pivot-stud 8, so that the weight of the arms tends to cause them to remain in either of the eXtreme positions to lwhich they are moved.

The solenoids A and B for actuating the main switch are mounted on. the plate 7 at opposite ysides of the pivot-stud 8. For each solenoid there is an upper angle-plate 3 2 and a lower angle-plate 33 of which the foot-portions are bolted to the face of the plate 7. Between the horizontal portions of said angle-plates there is a spool consisting of an up er end-plate 34, a tubular sleeve 35 and a ower end-plate 36 through which the sleeve 35 extends to tit within an open ing through the lower angle-plate 33. The peripheral portions of the plates and 36 are connected to each other by a plurality 0f vertical side-bars 37. The solenoid coil 38 is wound on the sleeve 35 between the ende lates, being of course, suitably insulated) therefrom. The upper end-plate 34 has a conical projection 39 extending down .into the sleeve 35 in spaced relation to the inner ksurface thereof. A tubular core 40 fits slidably within the sleeve the central oienin of the core being slightly larger tran tie largest diameter of the conical projection 39, so that when the core is raised to its highest position it .will not contact with said member 39. The parts 34, 36, 37, 39 and 40 are of soft iron, and the sleeve 35 if of non-magnetic material such as brass. When the solenoid is energized by a suitable current passing through the coil 38, the core 40 is drawn upwardly with a comparatively uniform force, owing to the pro` vision of the conical member 39 by which the air-gap of the magnetic circuit is reduced to a minimum and magnetic leakage avoided. i

To the lower ends of the solenoid cores 40 are pivotally connected the upper ends of links 41, and the lower ends of said links are pivotally connected with the lateral arms 42 of a rocking-lever which is pivotally mounted on a stud 43 secured to the plate 7 near the lower edge thereof, the axis of said studbeing in the vertical plane of the axis of the pivot-stud 8. Alternate energizaton of the solenoids moves the-rocking-leverbetween the position shown by full and dottedlines in Fig. l.

forked and straddles an extendedportion The rocking-lever has an upwardly extending arm -44 of which the upper end is,

45 of the arm 16. In said part 45 there is a i cam-slot consisting of two similar curvilinear portions symmetrically arranged with respect to the center of the arm 16, the said slot-portions having convave outer sides a and convex inner sides b. The ends ofy the cam-slot aremore distant from the'axis of the stud 8 than the central or intermediate portion of the slot', and the longitudinal center-line of theslot is a slightly modified epicyclodal curve generated upon a` circle concentric with said stud 8. A small roller I 46'its within the cam-slot, said roller being revoluble u'pon a pin 47 extending between the forked ends of the arm 44. When the rocking-lever is -tilted to either of the extreme positions shown by full and dotted lines in Fig. 1, the roller 46 rests in an end of the cam-slot, which thus formsa stop for limiting movement of the rocking-lever. As the rocking-lever is vmoved from al position such as shown in Fig. 3 toward a position such as shown in Fig. 4, the roller first presses upwardly against the side a' of the slot. and tends to tilt 'the switclrarms 14,

15 slightly farther in the direction of the arrows c in Flg. 3. As the movement of the rocking-lever continues, the 4rollerl presses against the sideI b of the slot as shown in` Fig, 4, moving the switch-arms in the direction of the arrow in said figure, and after passing the intermediate posltion shown in Fig. 5 the roller presses against the other side L of the slot so'that the movement4 ot the switch-arms is continued 1n the d1rec' tion of the arrow d until the roller has al@ most reached the end ofthe slot opposite that from which its movement started. It will be seen that when the roller is in either end of the cam-slot, the switch-arms are', in

effect, locked in position, since a force ap` -plied to the switchsarms and tending'to ent upper andvlower-end-portions 49 'and 50'which extend angularly toward thev face of the switchboard 7, as shown in Fig. 2.`

Said resilient end-portions form sliding contacts or brushes for engagement witi arcuate contact- plates 51, 52 and 53 secured on the face of the switchboard, the lower brush 50 constantly engaging the plate 5l, and the upper brush 49 having portions engageable with both of the plates and yEach of the arcuate contact-plates is disposed concentrically with the pivot-stud i3 of the rocking-lever, and the upper plates 52 and 53 are so arranged that the brush et) will disengage therefrom, respectively, near the termination of the movements of the rocking-lever caused by energization of the solenoids yA and B. The plates 52 and 53 are connected by wires 54 and 55 with the respective solenoids A and. B, the other terminals 'ofthe solenoids being connected by wires 56 and 57 .with binding-posts 58 and y59nearthe lower edge of the switchboard`7. A binding-post 60 is connected by wires 6 1 with the lower contact-plate 51.

Referring now to the illustrative circuitdiagram at the lower part of Fig. l, there is indicated a three-phase alternating-current motor 62 whih receives electrical energy from supply- mains 63, 6e and 65 connected through a manually-controlled switch 66. The branch 64 of the motor-circuit is er,N tended directly from the switch 66 to the motor, the branch 63 is connected with the binding-posts or terminals 27 and 28 of the automatic switch, and the third branch 65 is connected with the binding- posts 29 and 30. A thermostatic device is indicated, having a movable central member 67, a fixed Contact 68 which is engageable by the member 67 when the temperature reaches a determined maximum, and a ixed Contact 69 with which the member 67 is engageable when the temperature reaches a determined minimum. The contact 68 is connected with the binding-post 58 and the Contact 69 is connected withI the binding-post 59, while the energy for the thermostat-and-solenoid l circuits is derived from the mains 63 and 65,

f ce

which are connected respectively with the binding-post and the central member 67 of the thermostat by wires 70 and 71. lt will be seen that when the automatic main switch is in the closed position shown by the full lines in Fig. 1, a circuit through the solenoid B may be closed by movement of the thermostat-member 67 into engagement with the contact 69. Upon energization of said solenoid B the rocking-lever and switch will be moved to the open position shown by dotted lines in F ig. 1, and near the end of such movement the brush 49 will disengage from the contact-plate 53, thereby opening the circuit through the solenoid B. lit then the thermostat-member 67 moves to engagement with the contact 68 a circuit will be thereby closed through the solenoid A., causing the switch to be returned to the closed position,. and near the end of the closing movement the brush 49, will be disengaged 'n yact-plate 52 to open the circuit thi-eaV solenoid A. 1t should be particularsJ ed that the opening of each oli' the solenoid-circuits occurs only after the movement of the rocking-lever caused by energin-L t n or" the respective solenoid is nearly brush t9 ren'iaining in Contact es 5f). and 53 except at the expo nu t the rocking lever. Thus theie'is no reossinbity of the s `atch-mechanis i stopping at an intermediate position, as there is not only the momentum of the part-s to complete the movement after the breaking of the solenoid-circuit, but also a certain continued pull from the solenoid itself, due to the fact that its energization is not lost instantaneously upon the opening of the circuit. Duc tothe proportionally large part of the operating period during which the solenoid-circuits remain closed, smaller sol-eneide may be used, and less energizing current, 'than in switches of this general character 'wherein the circuit of the actuating solenoid or electromagnet is broken at or near the beginning of the moveemnt of the switch. The smaller operating current required for the solenoids, makes it possible to control the same directly from a, fairly delicate thermostatic device without danger of .injuring or destroying the thermostat contacts, while the contacts of the main switch may be of such proportions as to control effectively a very heavy current in the motorcircuit or the like.

New, having described our inventiomwhat we claim and desire to secure by Letters Patent is:

1. 1n an automatic electric switch, a pivoted main switch member having a carnslotted arm, a pivoted controlling-lever, a part carried by said controlling-lever and entering the cam-slot in said arm of the main switch. member, means for actuating said controlling-lever in alternating directions to move the part toward opposite ends of the cam-slot and simultaneously actuate the main switch member, the ends of said camslot forming abutments to limit movement of the controlling-lever, and the 4sides of said cam-slot adjoining the ends thereof adapted to engage said part to prevent movement of the-main switch member when said part is seated in either end of the cam-slot.

:2. 1n an automatic electric switch, a pivoted main switch member, an oscillating controlling member pivoted on an axis parallel with that ol said switch member, there being in the switch member a cam-slot having symmetrical end-portions curved divergingly from central portion adjacent to the pivotal axis oli switch member,l the controlling member having a part entering` said cam-slot and engageable with the sides thereof to a 'the switch member aboutg-yits fb traversing the intermedmte nerf r li e tion o1 the slot and to hold the switch membei' substantially stationary when. traversing the termlnal portions of the slot, and means' for acuaing said controlling member, said elements opening the circuits` during movement of the eonroiling member subse nent:` to the phases of movement during Whie ythe main switch member is actuated.

A structure as speciiedin claim 2,v 2o which the controlling member 1s gravit'-` biased to positions at which the part in t cani-siot lies in the terminal portlons of Said slot, whereby said controlling vmember after q )assing an intermediate position` of unstable 25 equilibrium tends to more on to the respe tive extreme position thereof.`

HENRY A. HoEscHEN; WILLIAM HoEsoHEN. A

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