US611088A - Bergk - Google Patents

Description

N0. GIL O88. Patented Sept. 20, I898.

- T. VON ZWEIGBERGK.

GOVERNING, REVERSING, AND BRAKING CONTROLLER.

(Application filed Feb. 23, 1898.)

(No Model.) 4 Sheets-Sheet l.

I J r 4% 1 L 6 I 0 ol 'ofe E 5 7 J a na V p V --6 D D3172 "V1 v3 d v V 0 10 l V5 1 h din I 6 2% I v 1 v I I E H d III (1)4 j E o E l L43 71""1: c e flbtven 0! N0. 6ll,088. Patented Sept. 20, I898. T. van ZWEIGBERGK. GOVERNING, REVERSING, AND BRAKING CONTROLLER.

(Application filed Feb. 23, 1898.)

(No Model.)

4 Sheets-Sheet 2.

d 2 1T Yfzfn 6 5566, J lfw enZ mr $426M %Wa MZ W No. 6ll,088. Patented Sept. 20, I898.

T. VON ZWEIGBERGK.

GOVERNING, REVERSING, AND BRAKING CONTROLLER.

(Application filed Feb. 23, 1898.) (N0 L) 4 Sheets-Sheet 3.

Patented sm. 20,1898.

No. 6ll,088.

T. VON ZWEIGBERGK. GOVERNING, IEVEBSING, AND BRAKING CONTROLLER (Application filed rm as, 1090.) v

4 Sheets-Shut 4.

(N0 Nodal.)

. duait H kg m 43min ylq fneaaeai (S49. 5 1M m: warns vt-rzas co. wmouwov, msmwonm. n. cy

UNITED STATES PATENT OFFICE.

TIIORSTEN VON ZIVEIGBERGK, OF CLEVELAND, OIIIO, ASSIGNOR TO THE VALKER COMPANY, OF SAME PLACE.

GOVERNING, REVERSING, AND BRAKING CONTROLLER.

SPECIFICATION forming part of Letters Patent No. 611,088, dated September 20, 1898. Application filed February 23, 1898. Serial No. 671,870. (No model.)

To (all whom it may concern/.-

Be it known that I, THORSTEN VON Zwnrc- BERGK, a subject of the King of Sweden and Norway, residing at Cleveland, in the county of Ouyahoga and State of Ohio, have invented a certain new and useful Improvement in Governing, Reversing, and Braking Controllers, of which the following is a full, clear, and

exact description, reference being had to the accompanying drawings.

One of the objects of myinvention is to provide a simple and compact controller which while requiring but two operating-handles shall have the capacity ofperforming the three operations of governing and reversing the motors of a car and applying a brake thereto.

Another object is to combine with the controller, brake, and connections an automatic switch for governing the current to the brake.

A third object is to provide simple and'eificient means for cutting out either motor and the equalizing cross connection between them provided for the electric brake.

The invention consists of the means I employ for attaining the objects above set out and other minor objects, and it may be best described as consisting of the combinations of parts hereinafter specified, and definitely enumerated in the claims.

The drawings clearly show my invention.

Figure 1 is a front elevation of the controller, the front cover being removed; and Fig. 2 is aside elevation of the same with the cover in place, but a portion of it broken away. Fig. 3 is a top view of the controller; and Figs. 4:, 5, and 6 are horizontal sections of the controller on lines r 4, 5 5, 6 6, respectively, of Fig. 1. Fig. 7 is an enlarged plan of the detent mechanism of the two cylinders, the position of the two operating-levers being indicated by dotted lines. In this view the govorning-cylinder is at the off position and the reversing-cylinder at the reversing position, while in Fig. at, where the same mechanism is shown on a smaller scale, the governing-cylinder is at the off position and the reversing cylinder at the ahead position. Fig. Sis a diagram showing the development of the two cylinders, their contact-fingers,

and the connections with the motors, resistances, electric brakes, &c.

The same letters of reference designate the same parts on all of the figures.

Iwill first describe the construction and operation of the controller itself and then its connection with the motors, resistances, and brakes and its operation when installed.

The controller shown includes a governing and a reversing switch, each consisting of a row of contact-fingers and a cooperating contactcylinder, the term cylinder being used in its ordinary acceptation in the controller art and meaning a shaft and various contact-segments carried thereby through the intervention of suitable insulation.

In the governing-switch, D represents the shaft of the cylinder, and d to (1 inclusive, the contact-segments, which are supported by suitable ribbed arms (Z, projecting from hubs D, which surround an insulating-sleeve D which itself surrounds the shaft. The arrangement of the governing-switch (which is of the series-parallel type) is such that the contact segments or plates d to c1 are all electrically connected together, and the contact plates (Z to (Z are electrically connected together, while the contact-plate d is insulated from all the others and is connected with the controller-frame, which latter is grounded. The connection between the contact-segments referred to is preferably made by copper strips D which are embedded in proximate hubs, while insulating-col lars D are placed between those hubs which are not in electrical contact and beyond the end hubs. The shaft D is j ournaled in suitable bearings e 6', carried by the controllerframe E, and has the usual operating lover or handle D Suitably insulated and supported are a series of contact-fingers u to a adapted to engage with the contact-plates of the governing cylinder. These contact-fingers are connected with resistances and with the motors in the usual manner, so that the lever D by turning the cylinder into successive positions connects the motors in series with themselves and with a number of resistances and then successively cuts out these resistances, then connects the motors in parallel through resistances, and then cuts out these resistances, leaving in its final position the motor in parallel without resistance.

H represents the shaft of the reversing and braking cylinder. This cylinder is built of segments h to 71 inclusive, disposed and connected as hereinafter explained. These segments are carried in the usual manner by suitable arms 71, extending from hubs H, which are separated by insulating-collars H 'np and surround an insulated sleeve ll which itself surrounds the shaft H. This shaft is journaled in suitable bearings e and 6 carried by the controller-frame, and is independent of the shaft J of the reversing-leverj, hereinafter referred to, and is adapted to be turned on its axis without regard to that lever.

The shaft H carries at its upper end the detent-wheel or, as it is usually called, indicator-wheel K, rigidly secured to it, and has notches with which a spring-pressed roller g is adapted to engage. The hub of this indicator-wheel projects above the shaft H, so as to leave a central recess, and in this recess loosely stands the shaft J, with which the re- .versing-leverj engages. This shaft J is also journaled in a suitable bearing 6 carried by the frame.

Between the bearing 6 and the hub 70 is a sleeve M, loose on the shaft J, but compelled to rotate with'it by a spline j on the shaft taking into a longitudinal groove n in the sleeve. On the under side of this sleeveis a projection 02, adapted when the sleeve is in its lowest position to engage with a corre spondingly-shaped notch 70 in hub 70. On the 'upper side of the sleeve N is a projection 12 which is adapted when the sleeve is elevated to engage with either of a pair of notches e and e on the under side of the bearing 6 From this construction it follows that if the sleeve N is in its lowest position the shaft J, and. hence the reversing-lever j, is in rigid engagement with the shaft H and'capable of operating the reversing-cylinder, whereas if the sleeve N is elevated theshaft J and the oprating-leverj are not only disengaged from the shaft H, but are locked in place by the projection 71. en gaging with one of the notches in the stationary bearing a.

Surrounding the sleeve N is an annular groove a into which take pins 19, projecting inward from a yoke or lever P, which is pivoted on a horizontal pivot to lugs projecting from the frame. This lever is therefore adapted to shift the sleeve along the shaft J.

Surrounding the shaft D of the governingcontroller above its detent-wheel L is a cam in the form of a collar 0, having projecting rims o 0 which at a certain point incline downward, as at 0 and thus leave between them a cam-groove 0. The downward bend 0 in this cam-groove is on the side which is next to the lever P when the lever D is at its off position. Into this groove projects a roller 19, carried by the lever P. This roller being in the depression 0 of the cam-groove when the operating-handle D is at the off position then holds the lever P in its lowest position, which is when the sleeve N is in engagement with the hub of the detent-wheel K on the shaft H. When, however, the operating-lever D is turned in either direction from the off position, the roller 19 is elevated by the higher portion of the groove 0 coming beneath it, and this elevates the sleeve N into engagement with one of the notches in the bearing 6 thus releasing the shaft H and locking the shaft J and the leverj.

From the description just given it will be apparent that whenever the lever D is at working position-that is, when there is any current on-the lever j is necessarily dis-. connected from the reversing-cylinder and locked in position. It is therefore not only impossible to reverse the motors while the current is on, but it is impossible to displace the reversing-lever. If desired, the rim 0 of the cam 0 may be omitted and a spring acting downward on the lever P substituted therefor. When the governing-lever is at the 06 position, if. the reversing-lever is turned to its oif position, which is between the ahead and the reverse positions, the projection n will come under the bearing e between the notches e and c. This prevents the elevation of the sleeve when in this position, and the sleeve holds the lever P and its roller 1) in stationary position, and this roller prevents the rotation of the collar 0 and thereby locks the governing-cylinder against movement. The lever j is removable only in its ofi position, and preferably the lever D also, as is customary; but, as shown, when the lever j is at its off position the lever D cannot be turned even if left on, and thus it the motorman is obliged to leave his car he may simply set the reversing-lever at the off'position, and he can then take off this lever, which is much smaller than the lever 13, and put it in his pocket.

The construction and operation thus far described are not claimed in this application, but in another application filed by me April 29, 1898, Serial No. 679,195.

In order that the controller may be able to govern and reverse the motors and apply the electric brake with simply its two cylinders and Without the necessity of lengthening the shaft of the governing-cylinder and putting on several contactsegments below those re-. quired for the governing operations, I add to the reversing-cylinder (on either side of the reverse position) contact-plates adapted to reverse the electric brake, I provide electricbrake positions for the governing-cylinder, which are back of the off position, and I supply a suitable connection between the two cylinders, so that when the operating-lever D is turned to one of these electric-brake positions the reversing-cylinder (from which turned thereby either into the position of electrio-brake ahead or electric-brake reverse, according as the reversing-lever left it at the ahead or the reverse position.

I will now describe in detail the connection between the two cylinders above referred to and its operation.

Referring more particularly to Figs. 4: and 7, where the detent-wheels L and K are shown in plan, it will be seen that the rollers q and g, which engage with the notches of these detent wheels, are carried by independent arms Q and Q, which for simplicity of construction are pivoted on one pivot at g and are forced into position by one spring g surrounding the studs 1 which project toward each other from lugs g on the backs of arms Q, and Q. If the lever D is revolved to the right, it turns the governing-cylinder through four series positions and three parallel positions until its movement is stopped by the projection Z of the indicator-wheel engaging with the roller g. This movement is totally independent of the reversing-cylinder. hen the lever D is brought back to the off position, the reversing-lever j is released and thrown into en gagement with the reversing cylinder, and the latter may be turned to reverse the motors by means of that lever. Between the ahead and reverse positions of this reverse-lever is the off position at which it may stop, if de sired, and at which it looks the lever D as stated. In the indicator-wheel K, on the side next to the indicator-wheel L, are a pair of notches 7t and These notches are in such position that one or the other of them is engaged by the projection Z of, the indicatorwheel L when the latter is moved from the off position to the first electric-brake position. Thus if, as shown in Fig. '7, the reversing-lever has left the indicator-wheel K in the reverse position (the car thus moving backward) the projection Zen gages with the notch h and before the lever D has come into the first electric-brake position the indicatorwheel K is turned to the right a distance sufficient to bring it into the electric-brake reverse position-that is, the last indicatornotch 7,1 comes into engagement with the roller and the last row of contact-segments 71 to 7t into engagement with the contactfingers. This leaves the electric brake so connected up that it is applied through two resistances. These resistances are cut out as the lever D is moved to the second and third electric-brake positions. lVheu the lever D is brought back to the olt position, it brings back the indicator-wheel K and the cylinder secured thereto to its former position. If in this position the reversing-lever is set at the ahead position, the notch L is brought into the position formerly occupied by the notch and if new the lever D is turned to the electriobrakc position the projection Z engages wilh the notch k and swings the re versing-cylinder into the position of electricbrake ahead, which is the position where the third indicator notch it engages with the roller g; It will thus be seen that if the re versing-lever leaves the reversing-cylinder at the ahead position that cylinder is in position to be turned into the electric-brake ahead position by the movement of the lever D to the electric-brake position, while if the reversing-lever leaves its cylinder at the reverse position that cylinder will be turned to the electric brake reverse position by the same movement of the lever D Therefore in ordinary running the lever D is the only one that need be handled, its forward move ment governing the motors and its rearward movement the electric brake, and when the car is to be reversed the one reversing movement of the leverj leaves the lever D in position to perform the same operations for the rearward movement of the car The operation of the controller for the series and parallel positions and of the revers ing-switch for the ahead and reverse positions will be readily understood by those skilled in the art from Fig. 8, where the controller is represented as connected with two motors and the resistance R, which may be in the circuit in its entirety (r) or only as to its portion 7' or its portion 0' R R R R represent the conductors leading to this resistance. A AA A AA and F FF F FF represent the conductors to and from the respective armatures and fields of the motors. T represents the conductor from the trolley, and S that to the automatic switch for the electric brake. The contact-fingers for the governing cylinder are represented by a to U10, inclusive, and those for the reversing and braking-cylinder by 4) to 12", inclusive. Of the latter the fingers 2), c and o are adapted to be held out of the path of their corresponding segments, thus cutting out the lines they represent, as hereinafter explained. 0 represents a conductor leading from contact fingers it and L6 to contact-finger o, and C represen ts a conductor leading from contactfinger a to contact-finger o".

I will now describe the course of the current for a few positions of the controller, as illustrative. When the governing-cylinder is in position No. *1 series and the reversingcylinders in position ahead, the current comes from the trolley via T to contact-finger it to contact-plate (Z to contact-plate d), to contact-finger it, through the total resistance r to conductor C, to contact-finger o, to con tact-plate 7t, to contactplate 72 to contact finger 73 through the armature of motor No. 1 to contact-finger N, to plates 7t it, to contact finger c, through the field of motor No. l to contact-finger 2 to contact-plates d d, to contact-finger it conductor G to contact-finger o, to contact-finger o through the armature of motor No. 2 to coutact-finger o to contact-finger r, and through the field of motor No. 2 to the ground. The positions 2, 3, and i cut out portions and then the whole of the resistance R, while the reverse position of the roversingcylinder rev rses the di- 45 and by means of the contact-segment h conswitch is at the brake position.

rection of the motors. In position No. 5 the current passes from the trolley to contactfinger u plate 01 plate d contact-finger u through the portion r of the resistance, and, dividing, partly to the conductor 0 and partly to the contact-finger of, plates (1 and d, contact-finger "a and the conductor 0 The current thus comes to the plates 0 and c of the reversing-switch and passes through the motors in parallel, coming out via the con- (luctor FF to the ground and via the conductor F to the plate al to the ground. Parallel position 6 leaves only the portion r of the resistance in circuit, and portion 7 cuts out the whole of it.

I will now describe the connection and operation of the brake.

In the diagram Fig. 8 I have indicated at B B brake-shoes for each axle of the motorcar, and B 13 B B indicate similar shoes to two trail-cars. This brake operates in the usual manner of an electric brake that is, by the current generated by the movement of the motor-armature flowing through fieldcoils carried by'the brake-shoe, which find an armature in a disk secured to the axle, and hence retard or stop that disk and the axle. Thus in turning on the electric brake the electric-brake terminal (indicated at S) is substituted for the trolley-terminal, and the current is reversed by the reversing-cylinder.

The electric-brake portion of the governingswitch shown is such as to connect the motors in parallel, though, if desired, they might be connected in series. If they are connected in parallel, it is necessary that there be a cross connection between their fields when they are braking to equalize their currents and prevent the greater current generated by one motor from flowing back and counteracting the current from the other motor. This cross connection, however, is only desirable when the motors are operating as generators for the electric brake. I therefore establish the cross connection at the reversing-cylinder nected with the segment h and the portion h of the segment it, (said segments adapted to engage with the field-terminal of motor No. 2,) and the contact-finger '0 which is connected with the field of motor No. 1, but is adapted to be cut out, as hereinafter explained. When this finger c is not cut out, there is in each of the electric-brake positions, therefore, a cross connection from F through h and h or through h and h to '0 to FF.

Should a motor burn out, it is not only necessary that it should be cut out, but that the equalizing cross connection between the two motors be cut out, so as to prevent the grounding of the brake-current when the reversing- I accomplish this by endowing the contact-fingers o, '0 and 42 which are part of the connection from the governing-cylinder and of the cross connection between the motors, with the capacity of being withdrawn entirely from the path of the reversing-cylinder, and I provide hooks V, adapted to take over pins '0, projecting from these fingers, and thus retain them in this withdrawn position. If motor No.1 should burn out, the motorman opens his controllercase and withdraws the contact-fingers o o and hooks them back out of the way, while if motor No. 2 is disabled he withdraws the fingers 12 41 y In either case he runs his car on the parallel positions 5,6,or 7 of the controller. In Fig. 8 the hollow squares at the right of the contact-fingers o o o illustrate the withdrawn position of those fingers.

I do not claim in this application, broadly, either the method of cutting out a motor by withdrawing a contact-finger or the mechanism incident thereto, as such are shown and claimed in applications, Serial Nos. 671,289 and 679,194, which I filed February 23, 1898, and April 29, 1898, respectively. I do claim herein, however, the combination of parts by which I can cut out one of a plurality of motors and alsoa cross connection between them when the parts are at electric-braking positions.

In order to automatically govern the electric brake, I provide between the terminal S and the brake an automatic switch S, capable of increasing the resistance to the brake-current when the latter rises too high either from the operators cutting out resistance too quickly or from the too-rapid revolution of the motorarmatures. This switch consists of a magnet s in circuit with the brake through a resist- .ance and one or more armatures adapted to short-circuit a whole or a portion of the resistance. In the form shown in the drawings there are two armatures, and three paths in parallel are thus provided for the current, the first and least resisting being via the conductor s to the armature to the conductor 5 and the magnet, the second being through a port-ion of the resistance 5 to the conductor 3, the armature s to the magnet, and the third being through the whole resistance 8 to the magnet. When the current first flows, it passes mostly along the first of these paths. As the current increases in strength the magnet draws the armature s away from its contact-point and leaves the current flowing mostly through the second path. If the currents strength increases still more, the second path is opened and the current flows through the whole resistance 3 The spring 8 resisting the movement of the armature s is weaker than the spring 8 which resists the movement of the armature 8 which results in the first-mentioned path being opened first. As the force of the current dies down the resistance is short-circuited by the armatures and again fails, it will be seen that such an being rigid with the reversing-switch, said automatic switch is very desirable for preventing the current rising too high on the one hand and for preventing it being wasted in overcoming useless resistance on the other.

hen there is no trailcar, the current passes from the brake on the motor-car direct to the ground. In order to provide for the application of electric brakes on the trailer, however, I provide between each brake and the ground connection a spring-jack WV. This jack has two terminals 20 w normally in contact with each other, and thus when there is no car following closing the circuit from the brake to the ground. \Vhen, however, a trailer is attached, a plug W, having a terminal w and a proximate bar of insulation 10 is inserted between the springs w and w. The spring is connected with the electric brake on the trailer, and it thus carries the current from the electric brake on the motorcar to that on the trailer, while the insulatingbrake w holds the spring 10 out of action. The current thus goes to the ground from the trailer. If a second trailer is used, it is plugged into the first trailers ground connection in a similar manner. Th us the electric brakes, no matter how many are used, are all in series, the current going to the ground from the last one.

Having described my invention, I claim 1. The combination, with a pair of motors and a controller, of a reversing-switch having contact-fingers and contact-plates adapted to connect the motors in one direction or in the reverse direction and having a contact-finger connected with the field of one motor and a contact-plate adapted to connect that finger with the field of the other motor, whereby a cross connection between the fields of the motors is adapted to be established by the movement of the reversing-switch, substantially as described.

2. The combination, with a pair of motors, and an electric brake, of a reversing-switch adapted to stand in four positions and having contact-fingers and suitable connections between the fingers and motors whereby when the switch is in the first position the motors are connected in one direction, when the switch is in the next position the motors are reversed and a cross connection established between their fields, when the switch is in the third position the motors are reversed without such cross connection, and when the switch is in the fourth position they are connected as originally except they have such cross connection, substantially as described.

3. In a controller, in combination, a switch, adapted to apply an electric brake, a reversin g-switch having positions for the motor and for the electric brake, a lever adapted to move the reversing-switch from the motor ahead position to the motor reverse position, and vice versa, and connecting mechanism between the applying-switch and the reversing-switch, one member of said mechanism mem her having two engageable parts with one of which a member moved by the applyingswitch must engage when that switch moves from the off to the electric-brake position, and vice versa, but the position in which the reversing-lever has left the reversing-switch determining with which one of said two engageable parts the other member engages,substantially as described.

4. The combination, in a controller, of a governing-cylinder, a reversing-cylinder, a plate secured to the shaft of the reversingcylinder, an arm carried by the governingcylinder and adapted to engage a shoulder on said plate when the governing-cylinder is turned to an electric-brake position if the reversing-switch is in the ahead position, and adapted to engage another shoulder on said plate when the governing cylinder is so turned if the reversing-cylinder is in the reverse position, the movement of the governing-cylinder in either event swinging the reversin g-cylinder to the corresponding electricbrake position, substantially as described.

5. The combination, in a controller, of a governing-cylinder, a reversing-cylinder, an operating-handle for the latter, a plate or other arm rigid with the shaft of the reversing-cyliuder, an arm moved by the governingcylinder and adapted to engage with said plate when the governing-cylinder moves from off to the electric-brake position in either of two positions according as the reversing-lever has left the reversing-switch in its ahead position or its reverse position, said two engageable positions of said plate being substantially the same angular distance apart as the ahead and the reverse positions of the reversing-switch, substantially as described.

6. The combination, in a controller, of a governing-cylinder, a reversing-cylinder, a projection carried by the governing-cylinder, a plate having two notches carried by the reversing-cylinder, one of said notches being adapted to be engaged by said projection when the governing-cylinder is turned to an electric-brake position if the reversing-cylinder is in its ahead position, and the other of said notches being adapted to be engaged by said projection when the governing-cylinder is so turned if the reversing-cylinder is in the reverse position, the movement of said projection, in either event, swinging the reversing-cylinder to the corresponding electricbrake position, substantially as described.

7. The combination, in a controller, of a governing-cylinder adapted to move in one direction from its off position to govern motors, and in the other direction to apply an electric brake, a reversing-cylinder having positions for the motors ahead or reversed and for the electric-brake ahead or reversed, a notched indicator wheel or plate for each cylinder, a spring-pressed roller or detent for each cylinder adapted to take into said notches, the indicator-wheel of the governing cylinder having a projection Z which comes between the last electric-brake position and the last parallel position, and by impinging on one side or the other against the roller for that indicator-wheel forms a stop for the governing-controller in either direction, and the indicator-wheel of the reversing-switch having a pair of notches 70 70 distinct from those used by the spring-pressed roller for that wheel and occupying such position that the projection Z,when the governing-switch moves from the off to the first electric-brake position, will engage with the notch 70 if the governing-switch is in the reverse position, or with the notch 70 if the governing-switch is in the ahead position, and in either case will move the reversing-switch to set it at an electric-brake position for that direction of car movement for which the reversing-switch was set before the governing-switch moved to apply the brake, substantially as described.

8. The combination, with a pair of motors and an electric brake, of a cross connection between the two motors, said cross connection being by means of a contact-finger and a contact-plate which are brought into engagement at an electric-braking position of a controller and a cut-out for each motor and for the cross connection which may be operated independently of the position of the controller which establishes the cross connection, whereby when either motor burns out its cut-out and the cut-out of the cross connection may be opened and the electric brake operated by the other motor, substantially as described.

9. The combination, with a pair of motors and an electric brake, of a cross connection between the two motors, said cross connection being by means of a contact-finger and a contact-plate of a controller which are brought into engagement at an electric-braking position, said contact-finger being adapted when the controller is at an electric-brake position to stand withdrawn from the path of the surface of the contact-plate with which it normally contacts in such position, and mechanism for retaining the contact-finger in this "withdrawn position whereby the cross connection may be cut out whenever a motor is to operate the electric brake, substantially as described.

10. The combination with an electric brake, of a controller adapted to apply the brake and govern it by cutting out resistance, and an automatic switch included in the circuit between the controller and the brake and short-circuitinga resistance at the time the brake is applied, but adapted to open that short circuit when the current strength increases to a desired amount, substantially as described,

11. The combination with an electric brake and a controller adapted to apply the brake, of an automatic switch inserted in the circuit to the electric brake, and adapted to increase the resistance to the current in that circuit as the strength of the current increases, substantially as described.

12. The combination with a motor, an electric brake, and a resistance, of a controller adapted to apply and govern the motor and brake by means of that resistance, and an automatic switch in the circuit between the controller and electric brake adapted to counteract too great an increase of the current strength caused by too rapid a revolution of the motor or too quick a cutting out of resistance by the controller, substantially as described.

13. The combination, with a motor, a controller and an electric brake, of an automatic switch in circuit with the electric brake, said switch comprising a magnet, armatures therefor and a resistance, said armatures when drawn toward the magnet being adapted to cut outpaths of less resistance than those th ereatter remaining, the armature which cuts out the path of least resistance being operated by a less magnetic pull than the other, substantially as described.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

THORSTEN VON ZWEIGBERGK.

Witnesses:

ALBERT H. BATES, E. B. GILOHR-IST.

cut out and thus the remaining motor used

Images