US1269655A - Electric switch. - Google Patents

Description

UNITED STATES PATENT OFFICE.

WILLIAM C. STEVENS, OF SUMMIT, NEW JERSEY, ASSIGNOR TO THE GUTLER-HAMMER MFG. CO., 0F MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented June .18. 191 R.

Application tiledA April 4, 1916. Serial No. 88,864.

To all 'whom it may concern:

Be it known that I, VVILLrAM a citizen of the United States, residin at Summit, in the county of Union and tate of New Jersey, have invented new and useful Improvements in Electric Switches, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This inventwn relates to improvements in electromagnetic switches for motor control and other purposes and more particularly to that type of switch wherein a single e011 serres to actuate the same and also to restrain its operation during excessive current conditions.

The invention has'among its objects to provide a :switchv of the aforesaid,type which will be more positive and reliable in operation and susceptible of a wider range of adjustment than those heretofore proposed.

A further object is to provide such a switch wherein adjustment may be obtained without atlecting the magnetic circuits thereof.

Other objects and advantagesof the invention will hereinafter appear.

The invention will now be more speciically described in connection with the accompanying drawing which illustrates one of the variousI possible embodiments thereof.

In the drawing,

Figure 1 is a front elevation of the switch, and,

Fig. 2 is a, side elevation thereof partly in section.

The switch includes cooperating contacts 1 and 2, the former heilig fixed to a support 3 upon a panel ft and the latter heilig yieldingly mounted 'in a conventional manner upon a movable arm 5. The arm 5 is lnounted upon a pivot pin (i carried by a'ud bctween extensions 7 of nou-magnetic bracketS fixed lo the panel 4. The' arm 5 is hifurcated or longitudinally slotted, to slraddle the hracket B and receive a .second arm 9 also pivotally mounted upon the pin 6. These two arms form armatures for an electromagnetic winding l0, and said arms arc so designed that the mechanical inertia of the C. STEVENS,

, former will materially exceed that of the mounted on panel 4. The core 11 is ositioned to aline with the upper end o the arm 9 while plate 12 has an extension 13 paralleling the core to aline with the upper end of arm 5. The core 11 and extension 13 thus form holes for the arms 9 and 5 respectively and said arms are respectively provided with non-magnetic plates 11 and 15 to prevent sticking thereof to said poles` Both arms 5 and 9 have rearward extensions, the former having a slotted extension 5." and the latter an extension 9 fitting Within the former. Extension 5 carries a cross bar 17 forming a stop for extension 9 and sab.y cross bar has an adjustable stop screw'lS to engage bracket 8, said extension 5 being bifurcated to straddle said screw. The arm 9, including its extension, is of magnetic material but the arm is of magnetic material only from its upper extremity including the entire extension 5, being of non-magnetic material. However, thenonmagnetic extension 5 is provided at its rear end with a magnetic block 19 in line with the end of magnetic plate 12 which projects downwardly through bracket 8. The front.

face of this block is in close proximity to the' magnetic flux thereof will hc divided between the two paths indicated in broken and dotted lines. The flux taking the broken line path obviously tends to attract thc arm 5 to close the switch, while that taking the dotted line path tends to attract the arm 9. Further, it will be observed that the flux taking the dotted line p'ath, in passing'through the magnetic block l!) attached to `the extension of arm 5 :in its way to the extension of arm S), also sei-vesto attract or holdA said block with the result of opposing,lr thx-attraction o1' arm 5 bythe flux taking the broken line path. Moreover, in view of the relation of the block 19 and extension 9 ol' armi), said arm may move to attracted position without varying the attractive force exerted on the block 19 and hence the force in opposition to the closure of arm 5.

The arm 9, however, is connected tothe 75 I to the point X, the remainder of said arm. i f

inertia of said extension of arm 5 through a tension spring 20. rl`his spring is connected at one end to a lug 21 on the magnetic block 18 and 1s connected at its opposite end by an adjustable device to a lug 23 on the extension of arm t). Hence it will be observed that when tli i arin 9 is attracted it will tension the spi-ing 20 thereby offsetting or compensating for the mechanical inertia of the ariii 5 to the extent of thc energy stored in said spring. In other words, the arm 9 upon attraction increases the sensitiveness of the ai'iii 5 to attraction by the magnet through the iiiediuin of springr 20.

Thus, considering the switch iii its entirety, the winding 1() when energized will exert opposing pulls on arm 5 and a unidirectional pull on arm 9. The pull on arm 9 is opposed only by the relatively slight mechanical inertia thereof and the minimized opposing force of spring 20,. while the magnetic opposing pull on arm 5 1s supplemented by the relatively great mechanical arm. Arm 9 will accordingly respond prior to arm 5 and in approaching pole 1l reduces the reluctance of the path of that flux actingr to attract the same and to oppose attraction of ai'm 5. This insures a strong opposingr same time eti'ects a change in the relative relnctances of the two magnetic circuits whereby a decrease in current will effect a greater reduction in thc flux of the dotted line circuit than in the linx of the broken line circuit. Moreover, the attraction of arm 9 tensions the spring 21| to supplement the closing piill exerted on arni 5 whereby at sonie critical currentl value the coinblned magnetic and mechanical forces exerted on arm 5 will necessarily preponderate the combined magnetic and mechanical opposing forces to close the switch. On the other hand, the construction described insures a time elenieiit in the closure of the switch whereby it' the winding is initially subjected to a current rising above said critical value the pi'epoiideration of the two opposing forces will necessarily be reversed with the resultof maintaining` the switch in open position until the current falls to said critiral value.

lf desired. the arni 5 may be designed to have, such ii'iechaiiical inertia as to posi tively insure against its attraction without the assistance of spring 20 oi' any of the well known means may he provided to retard the building up of the linx of the broken line circuit upon initial energization of winding 10. Such means will positively insure an opportunitV vfor action of thc. other means to control the switch as described. ltloieover. with the construction described, the sensitivcness of the ariii 5 for attraction by winding It), and hence the critical current "aluc, may be varied through a wide range pull on arin 5 but at the' of such pulls by mechanical and magnetic adjustments. The mechanical adjustment is afforded by the adjustable device 22 associated with the tension spring, which device enables varia,- tion of the degree of tension of spring 20 effected by attraction of arm 9. Thisnin turn, varies the degree of supplementation of the closing pull of magnet 10 and without in any wisc affecting the normal positioning of,the arm 5 or, in other words, without in any wise affecting either inagnetic circiiit. 0n the other hand, the magnetic adjustment is provided for by the adjustable stop screw 18 on the extension of arm 5, which provides for variation of the air gap between the lower extremityof the magnet frame and the magnetic block 19 on arm 5, and proportional variation in the air gap between the arm 5 and pole'13.. This in turn effects a variation in the relative reluctances of the two magnetic circuits with a consequent variation in the effect of rising and falling currents upon the fluxes of the two circuits. Obviously, therefore, these adjustments individually vide for adaptation of 'the varying conditions.

It will, of course, be understood that when the switch closes the arm 5 ap roaches poles 13 and 1l of the magnet to re uce the reluctance of the broken line magnetic circuit and at the same time separates the block 19 from the loweiend of the magnetic frame to increase the air gap in the dotted line magnetic circuit which insures a strong holding pull on arm 5 and further insures against subsequent prcdoinination of the opposing fluxes. j

WVhat I claim as new and desire to secure by Letters Patent is:

In an electromagnetic switch, in combination, coperating switch contacts, an actuating member for one of said contacts, electroinagnetic means subjecting said member to opposing pulls variable relatively by variations in the current supplied to said means and means adjustable to vary the sensitiveness of response of said member for aotua tion of said contact whilemaintainin a given relative adjustment of the opposing pulls of the said electromagnetic means.

In an electromagnetic switch, in combination, cooperating switch contacts, an actuating member for one of said contacts, electromagnetic means subjecting said meinbei-'to opposing pulls variable relativeljr b v variations in the current supplied to said means, means to eti'ect relative adjustment for response of said member at any one of a number of critical current values and means adjustable to vary the sensitiveness of response of said member while maintaining a given relat-iveadjustment of the opposing pulls of said electromagnetic means.

and jointly roswitch to wi ely 3. In an electromagnetic switch, in combination, coperating contacts, an actuating.

member for one of said contacts, an electromagnetic operating winding for said member having magnetic circuits whereby its magnetic flux exerts opposing pulls on said member and means subjected to a uni-directional pull. by said Winding and responsive to vary the sensitiveness of response of said member.

4. In an electromagnetic Switch, in combination, cooperating contacts, an actuating member for one of said contacts, an electromagnetic operating winding for said member having magnetic circuits whereby its magnetic linx exerts opposing pulls on said member and means subjected to a uni-directional pull by said winding and rcsponsive prior to said member to supplement the magnetic pull on said member in a single direction.

5. In an electromagnetic switch, in combination, coperating contacts, an actuating member for one of said contacts, an electromagnetic operating winding for said member having magnetic circuits whereby its magnetic flux exerts opposing pulls on said member-and means subjected to a uni-directional pull by said winding and responsive prior to said member to mechanically supplement the magnetic pull on said member in a single direction.

6. In an electromagnetic switch, in combingtion, copcrating contacts, an actuating member for one of said contacts, an electromagnetic operating winding for said membei' having lmagnetic circuits whereby its magnetic linx exerts opposing pulls` on said member and means subjected to a uni-directional pull by said winding and responsive prior to said member to supplement. the magnetic pull on said member in a single direction, said means being adjustable to vary the degree of supplementation of the pull on said member.

7. In an electromagnetic switch, in combination, cooperating contacts, an actuating member for one of said contacts, an operating winding for said member having magnetic circuits whereby its magnetic linx cxerts opposing pulls on said member and means responsive to said winding independently of said member to vary the reluctance of the magnetic circuit, thc flux of which opposes actuation ot said member.

8. In an electromagnetic switch, in conibination, coperating routards, an actuating member for one ot said contacts, an operating winding for said member having magnetic circuits whereby its magnetic flux ex erts opposing pulls on said I nember and means responsive to .said winding independ ently of said member to vary the reluctance of the magnetic circuit, the flux of which opposes actuation of said member, said means upon attraction also acting to supplement the reverse pull on said member.

t). In an electromagnetic switch, in combination, cooperating contacts, an actuating member for one of said contacts, an operim 10. In an electromagnetic switch, in com- 30 bination, coperating contacts, an actuating member for one of said contacts, an operting winding for said member having magnetic circuits whereby its magnetic flux exerts opposing member having means to adjust the Same for relative reluctance variation 4of said magnetic circuits, and means subjected to a uni-directional pull by said winding and.

responsive thereto to supplement the actut 9 atin pull on said member, said means 1ncluding adjustable means for varying the degree of such supplementation.

11. In an electromagnetic switch, in combination, cooperating contacts, an actuating member for one `of said contacts, an operating,r winding for said member having magnetic circuits whereby its magnetic flux exerts opposing pulls on said member, said member having means for adjustin same to vary relatively the norma reluctances of said magnetic circuits, means subjected to a uni-directional pull by said winding and adapted upon response to reduce the reluctance of one of said ma circuits and means controlled bysai former means to supplement the actuating pull on said member, said last mentioned means bein adjustable to vary the degree of such supp ementation. i

12. In an electromagietic switch,in.eoml bination, cooperating contacts, an electromagnetic wjnding and separately and progressively responding amature members for said winding, the member last to re 115 spend being operatively connected to one of said contacts for actuation thereof and said windingr having a magnetic circuit including both ot said members, such circuit subjecting said contact actuating member to a 12o restraining pull and being subjected to a reduction of its reluctance upon response of the other of said members.

I3. In an electromagnetic switch, in com- 9.'7 said magnetic" to a uni-directional pull: f;

pulls on said member, said 35 the 10a etic los bination, coperating contacts, an electro- 1,25`

magnet having separately and progressively responding armature members, the member last to respond heilig operatively connected to one of said contacts for actuation thereof, said electron'iagnet having a magnetic 13oy circuit including both of said members, such actuating pull of said contact actuating circuit subjectlng said contact actuating member following the attraction of the member to a restraining pull and being-subother of said members. 10 jected to a reduction in its reluctance upon In Witness whereof, I have hereunto subs response of the other of said members and scribed my name.

an energy storing connection between said armature members acting to supplement the WM. C. STEVENS.

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