US1731188A - Electric switch - Google Patents

Description

Oct. 8, I929. T. M. AVERY ELECTRIC SWITCH Filed July 22, 1921 2 Sheets-Sheet 1 Z'we MA very,

T. M. 'AVERY ELECTRIC SWITCH Oct. 8, 1929.

Filed July 22,- 1921 2 Sheets-Sheet 2 PM ff. A any, %/W@ Patented Oct. a, 1929 UNITED STATES PATENT OFFICE 'rnv'n 1r. AVERY, or ens- 's mums, NEW ronx, assIGNoB 'ro UNIoN BAG ararnn' coBronarIoN, or NEW roux, N. Y., a conroRa'rroN or NEW Yomr n ELECTRIC SWITCH Application filed July 28,

The present invention relates to im rovements injelectric switches or relays an more particularly to those'of the kindused for controlling the operation of a reversible electric 5 motor. I g The primary object of the invention is to provide'a novel and improved switch or relay of'this kind which is capable of acting quickly and, if necessary, at' frequent intervals in response to -a suitable controlling device, to supply current to a reversible electric motor to-cause running thereof in either forward or reverse direction, the motor circuit-controlling contacts being adjustable, whereby the gaps between them may be reduced to a minimum, and electro-magnetic devices operative in response to the controlling device servmg to so control the motor contacts that the direction of 'running of the motor will be changed immediately or the running of the motor initiated or interrupted promptly, as demanded by the controllin device, thus enabling a very close regulatlongof the motor to be obtained.

To these and other ends, the invention con sists in certain improvements and combinations and arrangements of parts, all as will be hereinafter more fully described, the fea-. tures of novelty being pointed out particularly in the claim at the end of the specification. I In the a ompanying drawings Figure l i -epresents a front elevation of an electric switch or relay constructed in accordance with the preferred embodiment of the invention;

through the switch or of Figurel; v 40 Figure 3 is a top lan view of the switch or relay as shown m i rel; Figure 4 is a bottom view of the switch shown in Figure 1; an Figure 5 represents diagrammatlcally a controlling systememploying the or relaV 1 s an element thereof.

v Electric switches or relays embodying the present inventionare applicable all installations where it is desira 1e or necesto sary to control the operation of an electric .ing screw bein gener lly to 1921. Serial No. 480,740.

motor and especially a reversible electric motor. The invention is particularly applicas ble to regulating or controlling systems, wherein the electric motor is employed as a 'reglulating or compensating means, the switc or relay when used in such systems securing promptresponseof the motor to the, device which controls it. In the present instance, the switch or relay is shown generally as applied to a system for controlling the speed of a web of paper or other materialtravelling through a paper bag making machine or the like, for the purpose of maintainingcorrect registration between the travelling web and a device or mechanism in the machine which operates on the web, substantially as illustrated and described in my Patent No. 1,517,099, granted November 25, 1924.

It is to be understood, however, that the in vention is not restricted to this particular use and also that the invention is not restricted to p the precise construction shown, as other uses 7 for the invention will suggest themselves and equivalent constructions are contemplated, and these will be included within the scope of the claim.

2 secure to its rear side and which serve to 30 support the switch or relayaon a wall, the

frame of a machine or the like, it being preferable to so mount the switch-or relay that t the base 1 occupies anupright position; A

removable cover '3 is preferably fitted to the a baselto normally enclose and thus protect the Figure 2 represents a vertical section. relay on the line 2-2 and 7 and contains a socket 10 in which a contact 11 ma be fitted adjustably, a clamp-,

I provided to secure the contact-in proper ad usted position. The base 1 has a pair of terminals 13 and 14 secured 10o which latter extend preferably through the base, as shown, and form bindingiposts for the respective motor connections. 'Additional screws 17 and 18 may be provided to assist in securing the terminals 13 and 14 to the base. Each terminal is provided with a contact holder which is formed with a socket 20 to receive a contact 21 and a clamping screw 22 is provided to secure the contact in proper positionwithin its respective holder.

The ends of the blades or arms 4 and 5 opposite to the contact holders are secured to a post or standard 23 which is secured rigidly to the base by a suitable number of screws 24. Preferably, the rigid stifl'ening strip 6 of each blade terminates short of the post or standard 23 and the relatively yielding or resilient strip 7 of each blade serves to connect the same with the post or standard, under the clamping action of the screws 25.

Electro- magnets 26 and 27 are provided to actuate or controltherespective switch blades 4 and 5. Each of these electro-magnets has a core which is preferably in substantially the form of a horse-shoe, the poles of which are presented to the, armature 8 on the respective switch blade, in order to secure a strong pull upon the armature when thecorresponding electro-magnet is energized by a current of relatively small strength. Preferably and as shown, the core of each electro-magnet comprises a pair of similar parallel pole- pieces 28 and 29 which are connected at the rear of the base 1 by an iron plate 30, these parts forming a core of substantially horse-shoe form with the poles thereof presented to the respective armature. It is also preferable to provide one of these pole-pieces with a winding, as is shown, in order to adapt the electro-magnet to operate under the influence of a current of small strength. When a single winding is used, the pole-piece which is without a winding will become a consequent pole to complete the magnetic circuit with the ara mature. An intermediate binding post 31,

which is common to both electro-magnets,

and a pair of binding posts 32 and 33, which are individual to the respective electro-magnets, are preferably provided to enable the necessary connections to be made. 1

Means is provided for adjusting the gaps between the contacts 11 of the switch blades and the cooperating contacts 21 for the terminals 13 and 14,.in order to secure prompt engagement of these contacts when their re spective electro-magnets are energized. Breterably and as shown, a post 34 is fixed by the screws 35' or otherwise tothe base 1 at a point adjacent to the contact-carrying ends'of the switch blades and this post has oppositely-extending arms 36' which overlie the switch blades 4and 5 and carryset'screws 37 which are adjustable in the respective arms of the post and are arranged to bear against the averages outer sides of the respective switch blades. By this arrangement, the set screws 37 will limit the outward swing of the switch blades, and hence will control the air gap between the armature and the electro-magnet of the respective switch blade, and these set screws will also control the air gaps between the contacts 11 on the respective switch blades and the corresponding relatively fixed contacts 21 on the base. The contacts ordinarily will be adjusted so that this air gap is substantially constant, usually about one-quarter of an inch, thus maintaining constant the, distance throughwhich each switch arm must move,

in order to engage the respective pair of con-,

13 and 14, through the respective switch blades 4 or 5. Preferably and as shown, the

line terminal is connected to one side of a fuse-block38, the other terminal of which is connected by a conductor 39 to the post or standard 23, by a screw 40.

One example of a practical application of the switch or relay is shown diagrammatically in Figure 5. In this instance, it is employed, for the control of an electric motor which functions to compensate for variations in the speed of a travelling web and to thereby maintain, within relatively close limits, correct registration between the web and a de vice or rnechariism which operates thereon. 41 represents a reversible direct current motor of the type using three terminals, the terininal 42 .being connected to the conductor 43 which is connected to one side of the line circuit which may supply current at the usual voltage, the terminal 44 of the motor is connected by a conductor 45 to the terminal 14 of the switch, the terminal 46 of the motor is connected by a conductor 47 to the terminal 13 of the switch, and aconductor 48, which is connected to-the other sideof the line circuit, extends to the fuse-block 38. The electro-magnets which control the switch blades are preferably connected in aseparate or local circuit which may be adapted to carry a current of relatively low voltage. As indicated, B represents a battery having a switch S connected therein and one side of this battery is grounded on the frame of the machine on which the system is used, as indicated at G. The conductor 49 of this local circuit leads to the common binding post .31 for the two electromagnets-26. and 27, this binding post being connected to one tcrminalof each electro-magnet winding. The other terminals of the electro-magnets which areconnected to the mounted on a shaft 54, so that they will be revolved in definite timed relation to the speed of operation of the device or mechanism which is to be registered with the web, these contacts being connected respectively to col-' lector rings 55 and 56, and the conductors 50 and 51 being connected to brushes 57 and 58 which constantly engage the respective collector rings, and a controlling contact 59 which is carried by a sprocket 60, which is freely rotatable relatively to the contacts 52 and 53 and is driven in accordance with the actual speed of the web, is caused to engage one or the other of the contacts 52 or 53, when variations in speed occur between the contacts 52 and 53 and the contact 59. The contact 59 is grounded on the frame of the machine, as indicated at G, through the shaft 54.

The mode of operation of the system thus described is briefly as follows :-When the controlling contact 59 is in a neutral position between the contacts 52 and 53, the local circuit of'the switch will be open and, in consequence, the motor circuit through the conductors .45 and 47 will be open, and hence the motor will be at rest.v Should-the speed of the web accelerate relatively to the speed of operation of the device or mechanism which is timed with the shaft 54, the contact 59 will engage the contact 52, thus completing the local circuit through the electro-magnet 26, in consequence of which the switch blade 4 will be actuated to engage its contacts 11 and 21, and the motor circuit will then be completed through the conductor 47. The motor will then run in one direction, andthrough the medium of the compensating mechanism which is fully shown and described in my application above referred to, it will retard the speed of advance of the web. Should the speed of the web become retarded relatively to the speed of operation of the device or mechanism which is timed with the shaft 54, the controlling contact 59 will engage the contact 53 andithe local circuit will then be closed through the electro-magnet 27, in consequence of which the switch blade 5 will be actuated to-engage its contacts 11 and 21, thus completing the motor circuit through the conductor 45. The motor will then run in an opposite direction, and through the medium of compensating mechanism as above referred to, the speed at which the web is advanced through the machine will be accelerated. As soon as the necessary correction has been made in the speed of the web, the controlling contact 59 will resume a neutral position between the contacts 52 and 53 and the motor circuit will be broken through the conductors 45 and 47.

A It is to be understood that the switch members have a normal tendency to disengage the contacts'when said members are not attracted by their electro-magnets. By mounting the switch in upright position so that the switch members are arranged vertically or substantially so, the switch members may be so balanced that a very delicate force will be sufficient to attract them and thereby cause engagement of the contacts.

By arranging the electro-magnetS in close proximity to the pivotal points of the switch blades and the motor controlling contacts at the free ends thereof and remote from their pivotal points, quick action is secured in the contact engaging and disengaging operations, and this action is assisted, to a great extent, by the regulating screws which regulate the air gaps between the contacts within relatively close limits, with the result that the motor or other device controlled by the switch will respond instantly to the demands of the controlling device. The switch will therefore insure close and correct regulation when used in a regulating system, and furthermore, itis adapted for use in situations where the switch is required to operate frequently or at cuit-controlling contact at its upper end, a

fixed circuit-controlling contact mounted at one side of said member to be engaged by the contact thereon when said member moves in one direction, an electro-magnet located at the same side of said switch member at which said fixed contact is located and operative, when energized, to move said member immediately in a direction and to an extent suflicientto cause engagement of said contacts, and a stop mounted at the side of the switch member opposite to that side atwhich the electro-magnet and fixed contact are located, the switch member having a normal tendency to rest against said stop, one of said contacts being adjustable in a direction toward or from the other contact to determine the gap between said contacts when the switch member rests against said stop and to space the switch member from the electro-magnet' when said member is in attracted position, and said stop being adjustable to limit the retraction of the switch member and to determine the gap between said contacts and also the gap between the switch member and the electro-magnet when the switch member is in-released position.

In testimony whereof I hav e hereunto set

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