US616956A - Electromagnetic brake - Google Patents

Description

No. 6l6,956. Patented Jan. 3, I899.

F. C. NEWELL. V ELECTROMAGNETIC BRAKE.

(Application filed Feb. 5, 1898.]

2 Shaets-Sheet I.

(No Model.)

No. 6l6.956. Patented Jan. 3, I899.

F. C. NEWELL.

ELECTROMAGNETIC BRAKE.

(Application filed Feb. 5, 1898.)

2 Sheets-Sheet 2.

(No Model.)

UNITED STATES PATENT @FFICE.

FRANK C. NEWELL, OF CHICAGO, ILLINOIS.

ELECTROMAGNETIC BRAKE.

SPECIFICATION forming part of Letters Patent No. 616,956, dated January 3, 1899.

Application filed February 5, 1898. Serial No. 669,268. (No model.) I

To all whom it may concern:

Be it known that I, FRANK O. NEWELL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have-invented a new and useful Improvement in Electromagnetic Brakes, of which the following is a specification.

My invention relates to an improvementin brakes for cars, and primarily for cars which are propelled by electricity and are to that end equipped with electric motors.

My improvement involves the use of the track-brake variety of brake, or that which is normally held in suspension out of contact with the track-rail to'be forcibly brought into contact therewith for checking the motion of the car, and I produce this forcible contact, when the brake action is required, by electric power applied through the medium of a su'it ably-arranged electromagnet.

The immediate connection for use With which I have more particularly devised my improvement is that of an electric trolleycar, and though I do not limit my invention thereto, since the principle is applicable to an electric car driven by electricity generated or stored upon it, because of having so particularly devised it, the description hereinafter contained is in the main confined to the invention as adapted to that connection, and it is so illustrated in the accompanying drawings, in Which Figure 1 is a longitudinal sectional View of the bottom portion of a car equipped with my improvement; Fig. 2, a broken plan view showing the frame on which the electromagnetic track-brakes are suspended from the truck-frame and the sway-bar-carrying toggle-lever mechanism for actuating the ordinary brake-shoes against the wheels and operative by hand from brake levers or spindles on the platforms with which the sway-bar is connected; Fig. 3, an enlarged broken sectional view of a springcontr0lled thrust-rod detail of the electromagnetic brake mechanism; Fig. 4, a diagram of the electromagnetic brake mechanism and the circuits-on which it is operated; and Fig. 5, a diagrammatic representation of the arrangement of the armatures, fields, brake-magnets, and resistance when the break-circuit is closed.

As applied to an electric trolley-car, the

gist of my improvement consists in utilizing the inertia of the moving car after disconnecting the motor or motors from the line-wire preparatory to bringing the car to a standstill, to convert each motor into a currentgenerating dynamo, and thus cause it to supply the current for energizing the brakemagnet to set the brakes. This may be accomplished by the mechanism illustrated in the drawings,which embodies my invention in the best form at present known to me, and of which the following is a detailed description.

A denotes an electric trolley-car of any desired general construction, provided, as is now customary for driving it, with two electric motors B and C, Fig. 4, suitably placed on the car and each being connected with one of the axles, respectively, near the opposite ends of the car in any well-known or suitable manner.

To avoid confusion and because of the lack of novelty therein, I omit any description and any showing in the drawings of the connection with the running-gear of the car of the motors and of the electric connection with them of a trolley, and it is to be understood that the circuits leading from the dynamos, into which the motors are converted, and containing the electromagnetic brake mechanism, all as hereinafter described, and shown in Fig. 4, are quite separate from and independent of the circuits through which the motors are supplied with current for driving them.

D denotes the main frame of the car-truck, in which are supported the axles E E, carrying the wheels E E all in a usual or any proper way, and between the wheels there extend transversely of the side bars of the truck-frame D the bars D D, braced midway between their ends by the cross-bar D and forming a supplemental frame. On the bars D',near the opposite ends of the supplemental frame formed with them, are seated, at their angular socket ends 1 r, the hanger-bars F F in openings, near the extremities of which are supported, onadjustable springs q, rods 1).

G G are electromagnets, each comprisinga spool suitably wound with insulated wire and having its pole ends extended horizontally outward, as shown at m m in Fig. 1, with rectangular downward extensions on m, terminating at their lower ends in shoes m m which are preferably connected by an interposed section m of insulating material, such as wood, to afford a shield for protecting the wiring of the magnet against injury from objects encountered on the track and which might otherwise be forcibly projected against the magnets by the motion of the car. Each magnet G is supported on the frame D by havin g its pole-sectionsm pivotally connected, as

' shown in Fig. 1, with thelower ends of a pair of the spring-controlled rods 19, through the medium of which the magnets are loosely hung on the bars F, with the shoe terminals 071 of their poles respectively coincident with the rails m which form the armatures of the magnets. As will be seen, therefore, when the magnets are energized, as hereinafter described, they are attracted to the rails, and the two magnets, which are suspended from opposite sides of the longitudinal center of the car-truck between the wheels E E should be suitably connected, as indicated, to cause them to move uniformly together.

To each member of the pairs of Wheels E E (only one member of each pair is shown in Fig. 1, owing to the nature of the view selected for illustration) is applied a brakeshoe H, suspended by a link 1) from the bottom of the car and pivotally connected with a cross head II between its ends. These cross-heads are pivotally connected together at their upper ends in pairs lengthwise of the car by bars H and to their lower ends are pivoted shorter bars or arms H having longitudinal sockets Z, Fig. 3, extending inward from their free ends, at which they abut against rigid perforated arms r, depending from the angular ends of the hanger-bars D, the perforations in which coincide with the sockets Z to admit into the latter through the perforations thrust rods 70, pivotally connected with the outer ends of the magnetcore sections on and surrounded by springs confined between said ends and the arms r.

The members of each pair of the rods 19 are connected lengthwise of the car below the plane of the bars F by bars F, of non-magnetic material, having pivotally, connected with them, between their ends, levers 71, respectively connected, pivotally, at their upper ends with the opposite end portions of a swaybar I, fulcrumed midway between its extremities upon the brace-bar D These levers i are longer than the normal perpendicular distance between the sway-bar and either connectinghar F. Hence they normally extend beyond the bottom of the sway-bar with which they are so connected as to extend, respectively, at opposite sides of its opposite end portions. Each lever 11 is pivotally connected from a point between its ends bya link 2" with a hanger-bar F near its center. Thus when the magnets under the effect of energizing them, as hereinafter described, are attracted against the resistance of the springs q to engage their armatures afforded by the rails m the continued movement of the carsay, in the direction toward the wheelswill, with the magnets clinging to the rails, force the thrust-rods 70 adjacent to the wheels E against the bases of the respective sockets Z in the arms H thereby forcing the brake-shoes for the wheels E against the latter by the force exerted against the lower ends of the heads H. As the lower ends of these heads swing toward the wheels E their upper ends swing in the opposite direction, and by their connection through the bars H with the pivotal heads 11 of the brake-shoes for the wheels Ff set these shoes against the latter. The purchase for the pressure with which the brakes II are set is afforded by the stop effect of the rigid arms 7" adjacent to the wheels E and against which the socketed arms H bear.

Obviously when the car is travelingin the opposite direction under the same conditions of applying the brakes as already described, with the ear moving in the direction toward the wheels E the thrust for setting the brakes H is by the arms H adjacent to the wheels E when the purchase for the settingpressure is afiorded by the arms ll against the stops 0" adjacent to the wheels E When it is desired to apply the brakes H by hand from a platform, the brake-spindle (not shown) thereon is operated, and by its connection through the medium of a rod h or the like with the sway-bar I turns the latter, thereby, owing to the species of togglelever connection with it of the bars F and F, depressing the magnets G and at the same time forcing them in the direction toward the wheels E to set the brake-shoes ll against the wheels in 'the manner hereinbefore d'escribed.

Following is the description of the magnetcircuits and of the external resistance-cm euits illustrated in Fig. 4.

From the positive brush w of the motor B there leads the conductor 10 to a terminal r, and a wire to leads from the corresponding brush w of the motor 0 to a terminal 'u. A conductor w leads from the negative brush x of the motor 0 to a terminal 12 and from an adjacent terminal r there leads a conducting-wire 10 to the positive side of the field of the motor B, from the negative side of which leads a conductor 10 to a terminal 12 A conductor 10 leads from the negative brush x of the motor B to a terminal o adwhich may be understood to be provided in suitably-accessible position on a car-platform ple by the inertia of the car in motion when the line-current is cut off, there is always liability of one to generate voltage greater than the other and interfere with the latter by sending current through it in the reverse direction. This, as will be seen, is obviated by the described circuit-wiring when the circuits are closed by bringing the contacts into engagement with the terminals, since it produces excitement of the field of each from the armature of the other, for the field of one is connected in series with the armature of the other.

.From the terminal 0 there leads a conductor 8 through the magnets G G, emerging therefrom as the conductor 5, containing a solenoid-coil K and branching at y at one side to a contact-bar g and at the opposite side to the first of a series of resistances L, in any desired number,connectedin series, as shown, and the final one of which is connected bya conductor 8 with the terminal 12 The four resistance-coils L shown are connected, re spectively, by conductors 5 and s with terminalsf, f,f and f carrying the spring-contacts f f, f and f to bear against the under side of the contact-bar 9.

K is the solenoid-core, suitably supported with relation to the coil K and carrying on a rigid pendent arm 6 to move with the core a cut-out or contact-breaking finger d, of porcelain or other suitable non-conducting ma terial.

The operation is as follows: WVheu it is desired to stop the oarand preparatory thereto, the motors B and O are disconnected from the line-wire, the contacts controlled by the spindle S are caused to engage the adjacent series of terminals, thereby throwing the positive terminals of both motors into multiple connection with the conductor .9 s of the external circuit-that is to say, the terminals 11 o, and v are connected, the conductors w and 10 are connected to connect the negative terminal of the armature of the motor 0 with the field of the motor B, the negative terminal of the armature of the motor B is cuit is closed from both motors through the external circuit, including the magnet-brakes G.

By the inertia of the moving car the rotation of the axles converts the motors into generators (dynamos) to energize the magnets G, thereby engaging them with the rails to stop the car and causing their braking action to be supplementedin the manner described by applying the brake-shoes H to the car-wheels. The brake-shoes, however, may only be applied ontrailers and are not necessarily provided on the motor-car.

An important purpose of my improvement is to provide for producing the brake action as the immediate result of the circuit-closer produced by operating the spindle S, and this by a uniform quantity of current from the dynamos irrespective of the speed at which the car is moving at the time the disconnection is made with the line-wire. Accordingly the arrangement of the mechanism is such as to produce proper working of the magnetbrakes at the minimum speed of the car, depending upon the cutting in automatically of resistance according to the rate of greater speed at which the car may be moving to maintain the desired uniformity in the volume of current for operating the brakes, so that when the car is disconnected preparatory to stopping it, while running at the maximum speed with all the resistances in or while running at the minimum speed with all the resistances out or with any gradation of speed between these extremes, only enough current will be given from the dynamos to work the magnet-brakes. In this Way unduly sudden stoppage is avoided and there is no danger of burning out. The resistance mechanism accomplishes these objects as follows: The normal condition, with the magnet-oi rcuits open, of the solenoid is that shown. The moment the car is disconnected from the line-current and its continued motion converts the motors into generators the current which energizes the magnets G, if it be not too strong, or, in other words, if the motion of the car be slow, will traverse the solenoid-coil and passby way of the conductor 3, leading therefrom, to the contact-plate g, thence. to the contact f and terminal f and over the conductor 8 to the conductor 3 and terminal v", which is connected by the circuit-closer t with the fields of the dynamos through the terminal 12 and conductor 20 and the terminal o and conductor 10 Under these conditions all the resistances are cut out. Greater strength of current will energize the solenoid-coil K to suckin the core K accordingly. Thus if the core be moved only far enough to interpo'se the cut-out d between the contact f 13 and plate 9 the last of the resistance-coils L will be cut in, causing the current to pass through it to the conductor 8 from the plate g to the contact f and thence over the conductor 8 Still further movement of the core will actuate the finger d to cut out in addition the contact f thereby short-circuiting the current through the contact f to the conductor 3 and through the last two of the series of resistance-coils, and so on, the furthermovement of the core in accordance with the.

strength of current further cutting out the contact f to send the current through the last three resistance-ooils over the conductor 8 or also cutting out the contact f to out in all the resistance-coils and send the current through them immediately from the coil K to the conductor More or fewer resistance-coils than the four illustrated may be provided, as' desired, and to provide for the sudden stoppage of the car under the full force of the current generated whatever the speed of the car may be, and thus to provide an emergency stop, the core K may be held against movement under the suction-force of the coil K.

While, as hereinbefore stated, the drawings illustrate my invention in the form which I consider the best for its embodiment for the particular purpose for which it has been devised and which has been demonstrated by actual practical service to be operative, the structure may, to adapt the invention to different conditions, be variously modified by those skilled in the art without departure from my invention. Hence I do not wish to be understood as limiting my invention to the particular construction herein shown and described, nor to the details thereof and combinations of parts, except where the intention so to do is made manifest by the terms of the more specific among the appended claims.

What I claim. as new, and desire to secure by Letters Patent, is

1. In combination with an electric car, an electromagnet track-brake device in a circuit independent of the car-motor circuit and supported with its poles extending to coincide with a track-rail forming the magnet-armature and to yield longitudinally relative to the car, means for connecting, at will, in said independent circuit,the motor,thereby to convert it into a generator operated by the inertia of the car in motion to generate the current for actuating said device, brake-shoes connected with said device to be applied, when it is in engagement with its armature, by the inertia of the moving car, an external circuit including said device, and resistance mechanism in said external circuit provided with means for regulating it according to the speed of the car, substantially as described.

2. In an electromagnetic brake system for cars, an electromagnet track-brake device in a circuit independent of the car-motor circuit, means for connecting, at will, in said independent circuit the motor, thereby to convert it into a generator operated by the inertia of the car in motion to generate the current for actuating said device, and resistance mechanism in said external circuit comprising one or more resistance-coils, a contact-plate and one or more contacts each connected with a resistance-coil by a separate conductor, and a solenoid carrying on its core a cut-out finger to move between said contacts and contactplate, substantially as and for the purpose set forth.

' 3. In combination with an electric car, an

electromagn et track-brake device comprising a supplemental frame extending transversely of the car on the truck-frame and supporting hanger-bars carrying spring-controlled rods, electromagnets yieldingly suspended on said rods and included in an electric circuit inde pendent of the car-motor circuit and having their poles extended to coincide with the trackrails forming the magnet-armatures, means for connecting, at will, in said independent circuit the motor thereby to convert it into a generator operated by the inertia of the car in motion to generate the current for exciting said magnets to engage with the rails, and brake-shoes pivotally carried on heads connected together from their upper ends, in pairs, by bars and each having a spring-controlled thrust-rod connection, from its lower end, with a magnet, substantially as described. a

4. In combination with an electric car, an electromagnet track-brake device comprising a supplemental frame extending transversely of the car on the truck-frame and supporting hanger-bars carrying spring-controlled rods, rigid perforated arms r on said supplemental frame, electromagnets pivotally suspended on said rods-and included in an electric circuit independent of the car-motor circuit and having their poles extended to coincide with the track-rails forming the magnet-armatures, means for connecting, at will, in said independent circuit the motor thereby to convert it into a generator operated by the inertia of the car in motion to generate the current for exciting said magnets to engage with the, rails, brake-shoes on heads H connected in pairs from their upper ends by bars H and having socket-arms H extending from their lower ends against said arms 1', and spring-controlled thrust-rods 70 extending from opposite ends of the magnets through said perforated arms into said socket-arms, substantially as described.

5. In combination with an electric car, an electromagnet track-brake device comprising a supplemental frame on the truck-frame and supporting hanger-bars carrying spring-controlled rods, electromagnets yieldingly sus pended on said rods and included in an electric circuit independent of the car-motor circuit and having their poles extended to coincide with the track-rails forming the magnetarmatures, means for connecting, at will, in said independent circuit the motor thereby to convert it into a generator operated by the inertia of the car in motion to generate the current for exciting said magnets to engage with the rails, brake-shoes pivotally carried on heads connected together from their upper ends by bars and each having a spring-controlled thrust-rod connection, from its lower end, with a magnet, and means for operating said brake-shoes by hand, comprising a swaybar on said supplemental frame having near each end a toggle-lever connection with a magnet and a connection with the brake-spindle on the car-platform, substantially asdescribed.

6. In an electric car, the combination with the two electric motors for driving it of an electric circuit, independent of the motor-circuit, connecting the field of each motor in series With the armature of the other, said incuit, connecting the field of each motor in series with the armature of the other, said independent circuit being normally open and having terminals in serial alinement, an electromagnet track-brake device in said independent circuit supported With its poles extending to engage a track-rail forming its armature, an external circuit connected with said independent circuit and having a terminal in alinement with its terminals, one or more resistance-coils and a solenoid cut-out device therefor in said external circuit, and circuit-closers for said terminals and operative to close said circuits and thereby convert said motors into generators operated by the inertia of the car in motion, substantially as and for the purpose set forth.

FRANK C. NEWELL. In presence of R. T. SPENCER, DAN. W. LEE.

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