US376630A - Electro-magnetic device - Google Patents

Description

. (No Model.) 2 Sheets-Sheet 1,.

G. F. BRUSH. ELEOTRO MAGNETIC DEVICE.

' No. 876,880. Patented Jan. 17, 1888.

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ELBGTRO MAGNETIC DEVICE.

No. 376,630.; Patented Jan. 17, 1888.

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UNITED STATES PATENT OFFICE.

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ELECTRO MAGNET'IC DEVICE.

SPECIFICATION forming part of Letters Patent No. 376,630, dated January 17, 1888.

Application filed December 19, 1885. Serial No. 186,188. No model.)

To all whom it may concern Beit known that I, CHARLES F. BRUSH, of Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Electro-Magnetic Devices; and I do hereby declare the following/to be a full, clear, and exact description of the invention, such as will enable others skilled in the art towhich it appertaius to make and use the same.

My invention relates to an'improvement in electromagnetic devices.

Under certain circumstances it is desirable to arrange an electro-magnetic device in such manner that a temporarily abnormal current will not cause the device to respond, even though such temporaryincrease may be beyond a predetermined point, where a cont-inuous abnormal current will result in the functional act-ion of the device. This I believe has not hitherto been accomplished. For instance, if there be included in a circuit of arc lamps electro-niagnets whosearmatures are adjusted to respond to a certain strength of current, and it the supplying current be started suddenly, an abnormal flow of current will result, owing to the fact that the carbons of the lamps are in contact and the resistance of the external circuit therefore low. This abnormal current, though temporary, may be of astrength sufficient to cause the electroniagnets to attract their armatures, which, in the cases under consideration, is not desirable.

The object of my invention is to overcome the above difficulty, however caused, and I accomplish it by mechanism shown in the accompanying drawings, Figure 1 of which shows, partly in section, one form of myin- Fig. 2 illustrates the invention as embodied in a multiple series cut-out.

A is an electro-magnet whose coil forms part of a circuit, B B.

Gis an armature pivoted at D in such a manner that the end of the armature toward the electro-magnet and directly under its influence will be considerably heavier than the otherend.

E is a cylinder closed at its upper end and open at the lower. A plunger, F, fits nearly airtight in the cylinder and projects from the lower end. The bottom of the plunger is rounded and rests normally on the remote end of the armature. The weight of the plunger is such that while, when resting on the armature, it assists to overcome the preponderance of the heavier end, it does not do so entirely. A pin, G, fastened to the plunger F projects through the side of the cylinder, and working in a vertical slot, H, limits the vertical motion of the plunger. The cylinder at its upper end is attached rigidly to the rod K, which passes through a hole in the lug L, which is securely fastened to the frame-work (a portion of which is shown at Z) of the apparatus. The cylinder is adjustably supported by means of a setscrew, M, passing through the lug and impinging on the rod K. This adjustment, it will be seen, serves to determine the position of the armature.

The action is as follows: I will assume, for the purpose of illustration, that the electromagnet is in a circuit of are lamps fed by a dynamo-electric machine, and that the distance of the armature from the magnet has been suitably adjusted. 7 If no current be flowing, theparts will bein the position shown by the continuous lines in the drawings, the plunger F being at its highest position from the preponderance of the magnet end of the armature. If, now, the normal current be sent through the circuit 13 B, the magnet will attract the armature, and the latter will move up toward the magnet, but at a rate limited to the motion of the plunger, which, being nearly air-tight, drops slowly, dash-pot fashion, andif the armature attempt to move faster than the plunger drops the magnet is then deprived of the assistance of the weightof the plunger, and as the relations of the weights and distances are suitably proportioned the magnetis unable to raise the dead-weight of the armature alone. Consequently when the plunger has descended to its lowest point, as shown by the dotted lines, the weight of the plunger is borne by the pin G, resting on the bottom of the slot H in the cylinder, and the armature will make no further movement except under the influence of an increased current to which it is set to respond. If, now, the current be temporarily stopped, as by the flashing of the machine,

the carbons in the are lamps will all in a few seconds have come together and again complete the circuit, causing an abnormal flow of current until the ares have been reestablished.

The action of my improved apparatus,under these and the similar circumstances above indicated as due to the sudden starting of the machine at full speed, will be as follows: \Vhen the current is stopped, the electromagnet will become inoperative and the armature will fall back, raising the plunger to its highest point, This will occur in the case of flashing while the carbons of the lamps are feeding into contact.- Then upon the reestablishment and consequent abnormal flow of current the armature will be attracted and the plunger commence to descend; but owing to the slow movement of the plunger, as above explained, before the armature can get to a position where it would be raised completely by the magnet, under the influence of the increased current, the abnormal flow of current will have ceased, the normal arcsin the lamps having become established.

It will of course be understood that the movement of the armature when fully attracted by the magnet may be utilized to perform any desired function The magnet A may be located in a shuntto some electro-reeeptive device or devices operated by a main current.

In Fig. 2 I have shown the invention as applied to a multiple series cut-out, in which a is the supporting-frame having two insulated binding-posts, b c, fastened thereto. One end of the main circuit B is secured in the post 0. Incandescent lamps or other electro-receptive devices, (I, are included in the branch circuits 0, which latter are connected at their opposite ends to the conductor f, the opposite ends of which are connected, respectively, to the binding-posts b c. Electro-magnetg is wound with two coils, h and t, the coil h being ofhigh resistance and forming a constantly-closed shuntcircuit around the group of incandescent lamps or other clectro-rcceptive devices, (I. The other coil, 2', is of coarse wire, and has one of its terminals attached to a conductor, i", which is connected to the binding-post c, and its other terminal, 1, forming a contact, I, which is located in close proximity to the lower end of the conductor 6, attached to the binding-post Z). The terminal 2' serves as a spring-contact, and is normally out of contact with'the end of conductor i. An armature, G, is pivoted at d, the end Z, located beneath the electro-magnet, being considerably heavier than the opposite end, Z. The plunger F rests upon the end Z of the armature and operatesin the mannerhereinbefore described.

The operation of the multiple series cutout is as follows: \Vhen the lamps d d, &c., are in operative condition, the normal current on the line B B will divide itself between the lamps (Z, excepting the small percentage of current which will pass around the group by the shunt-circuit, including the fine-wire coil It. Should a number of the lamps (Z become inoperative from any cause, the increased current diverted through the fine-wire coil it will energize the magnet g sufficiently to raise the armature O and cause the latter to force the contact I into engagement with the lower end of the conductor 2", and thus form a shunt-circuit of low resistance around the group of lamps, through which low-resistance shunt the current will be diverted. As this low'resistance circuit has the coarse-wire coil of the magnet included therein, the current flowing through it, when the circuit is closed, will augment the strength of the magnet g, and thus hold the armature firmly in its raised position. In order to prevent the armature C from responding to an abnormal flow of current of short duration, due to the causes specified, or to any other, and which would operate to cut out the group of lamps d, I provide the cut-out with the plunger attachment, which causes the armature to rise so slowly that the abnormal flow of current will have ceased before the armature can rise to a position where it could be completelyraised by the lifting power of the magnet. Thus the cut-out will automatically switch out of circuit the group of lamps d whenever a predetermined number of them should fail to operate, but will not respend to an abnormal flow of current of short duration, and thereby accidentally switch the group of lamps out of circuit. The cut-out is provided with a switch-lever, S, for manually switching out of circuit the group of lamps d.

Fig. 2, and the descriptive matter relating thereto, is incorporated herein simply to make compliance with the request of the Patent Ofiice that some practical embodiment otthe invention should be disclosed; but by this disclosure I do not relinquish any right to claim any subject-matter of invention that may exist in the device illustrated in Fig. 2, and reserve such right for a separate application.

I do not limit myself to the special construe tion or arrangement of parts shown.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination, with a helix included in an electric circuit and an armature, of a supplemental actuating device constructed and arranged to operate slowly through a predetermined distance and assist the helix in moving the armature gradually to a predetermined distance from the helix and then to release the armature to the sole action of the helix, substantially as set forth.

2. In an electromagnetic device consisting primarily of. an elcctro-magnet and an armature controlled thereby, a dash-pot, the moving portion of which, without being connected, except by simple contact, with the armature or moving parts attached thereto, assists the armature, during it portion of its movement, I I In testimony whereof I have signed this to respond to the attractive influence of the specification in the. presence of two subsoribmagnet but at alimited rate of motion, the ing witnesses.

position of said movable portion .of the dash- CHAR-LES F. BRUSH. pot being controlled by said armature when XVitnesses: not under the influence of the magnet sub- ALBERT E. LYNCH,

stantinlly as setforth. L. B. LE VAKE.

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