US1024896A - Electromagnetically-operated switch. - Google Patents

Description

G. H. HILL.

BLEGTROMAGNBTIGALLY GPERATED SWITCH.

Patented Apr. 30, 1912.

APPLICATION FILED JANA, 1906.

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GEDRGE H.HILL- h 'am Attq.

G. H. HILL.

BLEGTROMAGNETIOALLY OPERATED SWITCH.

APPLIGATION FILED n.4, 1906.

1,024,896. Patented Apr. 30, 1912 2 SHEETS-SHEET 2'.

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UNITED STATES PATENT OFFICE.

GEORGE E. HILL, OF SbH'ENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC OOMPANY, A CORPORATION 01! NEW YORK.

ELECTROMAGNETICALLY-OPERATED SWI'IGH.

Specification of Letters Patent.

Patented Apr. 30, 1912.

Application filer! January 4, 1906. Serial No. 294,563.

To all whom it may concern:

Be it known that I, Gnonon H. HILL, a: citizen of the United States, residing at.

The present invention relates to switches and more particularly to electromagnetically-actuated switches wherein the energizing current is alternating.

In switches adapted to carry heavy currents it is necessary that the contacts be maintained in engagement with considerable pressure in order to make good electrical connection and prevent sparking. In electrom-agnetically-operated switches, such, for example, as are employed in controlling the motor circuits in electric locomotives or street cars, the proper engagement between the contacts is secured by maintaining a sufficient pull on the plunger of the electromagnet to force the contacts into engagement with each other with the proper pressure, the switch being, however, entirely free to open as soon as the pull on the electromagnet cease. The desired pull on the plunger of the electromagnet may readily be obtained when direct current is used for energizing the electromagnet, since the pull does not fluctuate but is maintained at a constant value and need be but little greater than that necessary to close the contacts. When a single phasealtcrnating current is employed, however, the magnetomotive force varies from zero to maximum during each quarter cycle, so that the pull upon the plunger uctuates widely; and, when the load upon the plunger is nearly equal to the pull of the clectromagnet the plunger vibrates and chatters, by reason of the load overcoming the pull of the electromagnct during the periods of low magnetomotive force, moreover, the pull upon the plunger does not increase as rapidly during the attraction of the plunger in the case of alternating current as it does when direct current is employed. It is evident, therefore, that if the usual type of electromagneticallyoperated switch applicable for use on direct currents is energized by alternating current, it is impossible to prevent chattering of the plunger and switch contacts unless the electromagnet is made much larger.

The object of the present invention is to produce an electromagnctically-actuated switch which will operate satisfactorily on alternatin currents.

I have ound that when there is no load upon the plunger of an electromagnet, except that due to its own weight, it may readily be maintained in its operated position without material vibration; and therefore the present invention contemplates a construction and arrangement of parts wherein, after the plunger of the electromagnet has been actuated to give a strong closing effort to the switch, it is relieved of this load, so that the function of the energizing current thereafter is solely to maintain the plunger raised.

The present invention in its various as pects will be more fully understood, and further objects and advantages will appear from the following description thereof. 1

I have illustrated a preferred embodiment of the present invention in the accompanying drawing, wherein- Figure 1 is a side elevation of my improved switch, parts of the casing surrounding the contacts being broken away; F ig. 2 is a front elevation of the switch; Fig. 3 is a cross-section taken approximatel through the center of the switch along a plane parallel with the plane of movement of the switch arm; and Fig. 4 is a bottom plan view of the movable switch member and operating connections between it and the plunger of the electromagnet.

Reference being had to the drawing, 1 indicates an electromagnet, and 2 and 3 the contacts of a switch adapted to be operated by said elcctromagnet. The electromagnet comprises a field frame 4, preferably composed of a number of U-shaped laminations clamped together, together with energizing coils 5 and 6 and a plunger 7. The field coil. Brackets 11 and 12 connect the lower ends of the arms 9 and 10 together, 'while the fastening bolts 13 aid in clamping the laminae into one rigid structure. A bracket 14 is secured to the p'osite end of the field magnet by bolts 15, thereby clamping the laminze securely together at this end of the magnetframe. Theswitch may be secured in position by means of bolts passing through cars 14 on bracket 14. The fixed contact member 2 is supported in the usual way within an arc chute 16 supported upon the side of the field magnet frame. The movable contact member 3 is supported upon the brackets 11 and 12, preferably by means of an arm 17 pivoted on one end. of a bellcrank lever 18, and held in its normal position with the shoulders 19 and 20 in engage ment with each other by means of a spring 21. crank'lever is rotated, contacts 2 and 3 are first brought into engagement with each other and then, upon the continued movement of the supporting lever, contact 3 moves across contact 2 with a wiping and rolling action. The movable contact is connected to,terminal 22 by means of a flexible conductor 23 which is secured at one end to thetermin'al and at its other end to the arm 17. The immediate operating means for the movable contact member is a toggle 24 pivoted at 25 between the brackets 11 and 12, and at 26 to one arm of the bell-crank lever 18.. The parts are so proportioned that when the switch is fully closed, that s, when the contacts 2 and 3 occupy the positions shown in Fig. 3, the joint 27 in the toggle is substantially in the line connecting the ivots 25 and 26, so that the toggle acts 0 its own accord to maintain theswitch closed. A pin 27, whereby the two parts of the toggle are hinged together, passes through a large opening 28 in the lower end of the plunger 7, or in a member 29 which is sccured to the lower end of the plunger. This opening may consist of a slotrelongated in a vertical direction, or ma be circular in shape, but having a consi erably larger diameter than the diameter of the in 27; so that after the toggle is straig tened the plunger may drop appreciably before striking-the pin. This lost motion between the toggle and the plunger permits the strain to be taken from the plunger after the switch has been closed so that any slight drop, or tendency to drop, in the plunger, will not be accentuated by reason of the back pressure of the switch member. By permitting the plunger to drop through a predetermined distance before engaging the toggle, the plunger is enabled to acquire sutficient momentum to displace the pin 27 out of alinement with the pivots 25 and 26 and thereby cause the switch to be opened. It will therefore be seen that the magnet may By this arrangement, when the bell-' be made sufficiently powerful to close the switch with a strong pressure between its contacts, while at the same time the opening of the switch is controlled by the plunger without requiring it to be constantly subjected to the tension due to the pressure between the contacts. Moreover, it will be seen that the toggle provides an increasing leverage as the plunger rises so that the contacts are pressed together with great force.

Beneath the main switch members I have shown interlocking switches or contacts 30 mounted in a casing 31 which is secured to the lower ends of the brackets 11 and 12. The rod 32 carrying the movable, elementsof the interlocks is actuated by means of a bell-crank lever 33 pivoted at 34 between the brackets 11 and i2 and having a sliding con nection 35 with a cross-bar 36 on one member of the toggle. These interlocks are similar to those shown in my prior application, Patent #815,826, dated March 20, 1906, but are located beneath instead of at the side of the electromagnet.

It is of course understood that while the arrangement shown constitutes the preferred form of my invention, it may be desirable in some instances to employ a different form of electromagnet for operating the toggle, or it may be desired to operate a different type of switch by means of the electromagnet shown and described, and therefore in some of its aspects the present invention is not limited to a construction embodying both of these features of invention. Moreover, while the present invention is particularly applicable for use in alternating current systems, it may of course be employed equally well in direct current systems. i i

What I claim as new and desire to secure by Letters Patent of the United States, is: 1. In an electromagneticallyoperated switch, fixed and movable switch members,

a toggle connected to said movable switch i member and arranged to. operate the same, an electroma et havin a lunger movable in the field ereof, and a lbst motion connection between said plunger and said toggle whereby when the switch is closed said plunger is substantially relieved from pres sure tending to move it out of the field of the magnet.

2. In an electromagnetically-operated switch, fixed and movable switch members, a toggle connected to said movable switch member for operating the same, an actuating coil, a plunger movable in the field thereof, an extension from said plunger having a hole therein, and a pin in said tog gle passing through said hole and considerably smaller than the hole in said extension.

3. In an electromagnctically-operated switch, a laminated U-shaped magnet frame, an energizing coil housed between the arms of said frame, a plunger movable v in said coil in a direction parallel to said of the arms of the magnet frame together,

arms, a movable switch member connected to said plunger, and brackets respectively at the free ends of the arms of the magnet frame and at the opposite end of said frame for clamping the laminae together, said movable switch member being supported upon the brackets at one end of said frame and the other brackets serving as a main support.

4. In an electromagnetically-operated switch, a laminated U-shaped frame, an energizing coil housed between the arms of said frame, aplunger movable within said coil in a direction parallel to the arms of said frame, brackets clamping the free ends a fixed switch member, a movable switch member pivotally supported upon said brackets, a toggle pivotally supported at one end of said movable switch member and at the opposite end to said bracket, and a loose'connection between said toggle and said plunger.

5. In an electromagnetically-operated switch, an electromagnet having a movable plunger, a fixed switch member mounted upon one .side of the electromagnet, a movable switch member, an operative connection between said movable switch member and the plunger of the electromagnet, auxiliary contacts including fixed and movable members located beneath the lower end of said plunger, and an operative connection between the movable member of said auxiliary contacts and said plunger.

6. In an electromagnetically-operated switch, a fixed switch member, a movable switch member, a lever to which said movable switch member is pivoted, a spring for yieldingly holding said movable switch member in a certain position relative to said lever, a toggle arrangedto move said lever and throw the movable switch member into engagement with the fixed switch member, an electromagnet having a movable plunger, and a lost motion connection between said plunger and said toggle.

7. In an electroniagnetically-operated switch, a fixed switch member, a movable switch member arranged for engagement therewith, a bell-crank lever to which said movable switch member is pivoted, a spring for yieldingly holding said movable switch member in certain relation to said lever, a toggle connected to said lever and arranged to operate the same, an electromagnet having a movable plunger, and a connection between said plunger and said toggle arranged to permit limited movement between said toggle and said plunger.

8. In combination with an electromagnet, a movable core the'rein,a circuit closing device, transmitting mechanism for operating said circuit closing device by said core-to close circuit, and a loose joint in said mechanism for permitting said core to be vibrated by current alternations in the magnet coil without imparting said motion to said circuit closing device.

9. In combination with an electromagnet, a movable core therein, a circuit closing device and mechanism interposed between said circuit closing device and said core for actuating said device by said core; the said mechanism including a pin' and a plate having an elongated slot receiving said pin, one of said parts being movable with respect to the other and one of said parts being connected to the core and the other to the circuit closing device; theaforesaid elements being constructed and arranged so that, upon the energizing of said magnet, said core shall be raised to transmit motion through said mechanism to operate said circuit closing device to close circuit, and thereafter upon said core assuming an equilibrated position in the magnet the relative movement of said pin and plate bration of said core bycurrent alternations in the electromagnet coil shall not be transmitted through said pin and plate to said circuit closing device.

10. In combination with an electromagnet, a longitudinally movable core therein, a circuit closer, transmitting mechanism for actuating said circuit closer including a horizontally projecting pin, and a p ate having an elongated vertical slot supported on said core and receiving said pin; the aforesaid parts being constructed and arranged so that upon the energizing of said magnet said core shall be raised to cause said plate in move said mechanism to operate said circuit closer, and thereafter upon said core assuming an equilibrated position in saidmagnet'said plate shall be moved up and down upon said pin, without imparting motion thereto, by the vibration of the core due to current alternations in the elcctromagnet coil.

In witness whereof, I have hereunto set my hand this second day of January, 1906.

BENJAMIN B. HULL, HELEN Onrono.

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