US1912911A - Speed responsive apparatus - Google Patents

Description

Jime 6, 1933.

F. H. NICHOLSON SPEED RESPONSIVE APPARATUS Filed Jui 2 1951 L 2 Brake Y Ma nezl C D 1 Y X E Bmlie (271211 0111129 Y Mgg'nez. .D o Y Relay Bela P101; -up 2 5 Cazpem b 9 1,1 11 b xa low C VCI \/('2 V65 SPPQd Relay Release *7 1 72 17297 FL 5 Relay P101-Zlp- ,9 g Relag CUPPQHZ Relay Helease' 9 4 e b 1,1- p253 70 1kg]? kelag CI Speed Current Relay zme P iCli up Hg. 4.

I 5 INVENTOR. Relay 1 1g A Release By F H160 0150/7 ,15 litz/121M411 ML ATTORNEY.

Patented June 6, 1933 UNITED STATES PATENT OFFICE FRANK H. NICHOLSON, OF'EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA SPEED RESPONSIVE APPARATUS Application filed July 20, 1931. Serial 110,551,967.

My invention relates to speed responsive apparatus. I

One object of my invention is the provision of novel and improved speed responsive apparatus which is simple, rugged, reliable, and inexpensive to manufacture, and which at the same time is highly sensitive to speed variations both accelerating and decelerating.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating one form of apparatus embodying my invention. Fig. 2 is a similar view showing a modified form of the apparatus illustrated in Fig. 1, and also embodying my invention. Figs. 3, 4 and 5 are diagrams, showing graphically, the operating characteristics of a portion of the apparatus illustrated in Figs. 1 and 2.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, speed responsive apparatus embodying my invention is here shown as comprising a cam member B and a cam follower A which cooperates with the cam member B. The cam member B is of suitable electrical conducting material, such as brass, and is intended to be operatively connected with any body or device whose linear or angular speed it is desired to measure, in such manner that the speed of rotation of the cani member will be proportional at all times to the speed of the body or device. For example, assuming that it is desired to measure the speed of a locomotive or car, the cam member B may be connected directly with, or geared to, an'axle or other convenient part of the running gear of the locomotive or car, in which event the speed 'of rotation of the cam member will increase or decrease as the speed of the locomotive or car increases or decreases.

The cam follower A, which is likewise constructed of suitable electrical conducting material, such as brass, is pivotally supported at one end on a suitable pivot indicated at 1 in the drawing, and has its free end shown, is such that its peripheral surface is substantially in the form of a portion of a spiral, the two ends of the spiral surface being joined by a radially extending portion 2. With this construction, it will be seen that if the cam member B is rotated in the direction indicated by the arrow, each time the radially extending portion 2 passes the end of the cam follower A, the follower will leave the surface of the cam member for a substantially fixed interval of time, the length of which depends upon'the mass of the follower A and the pull of spring S. It will also be seen that since the time interval during which the cam follower is out of engagement with the cam member during each revolution of the cam member is substantially fixed, the time interval during which the cam follower remains in engagement with the cam member during each revolution will decrease as the speed of rotation of the cam member increases.

Secured to the cam member B, and in electrical contact therewith, is a slip ring 4 which cooperates with a brush 5. The function of the slip ring 4 and the brush 5 will become apparent as the description proceeds.

The apparatus also includes a reactance C v and an electro-responsive indicating device, here shown as a relayD. The reactance C and the relay D are connected in series in a circuit which passes from terminal X of a suitable source of current, not shown in the drawing, through cam follower A, cammenn ber B, slip ring 4, brush 5, reactance C, and the winding of relay 1) to the other terminal Y of the source. Connected in multiple with the reactance C and relay D in the circuit just traced, is an asymmetric unit R which is so disposed that it will offer its highest resistance to current which tends to flow through the branch path including this unit from terminal X to terminal Y of the source.

The operation, as a whole, of the apparatus thus far described is as follows: When cam member B is rotated, the previously described coaction between the cam member and the cam follower will cause the circuit for relay D and reactance C to be opened for a fixed interval of time during each revolution of the cam member, and to be closed for a variable interval of time the length of which is inversely proportional to some function of the speed of rotation of cam member B. Each time the circuitfor relay D and reactance C is opened, the current in the winding of relay D will start to decrease, but this current will not immediately decrease to zero because the energy stored in this winding and in reactance C will cause a circulating current to flow in the closed circuit formed by reactance C, the winding of relay D, and asymmetric unit R, and this circulating current will delay the decay of current in the winding of relay D. Similarly, each time the circuit for reactance C and relay D is reestablished, the current in the winding of relay D will start to build up, the rate of growth of this current being determined by the inductance of the circuit. For a given proportioning of the parts, the growth and decay of the current in the winding of relay D when cam member B is rotated at a relatively low speedis indicated by the curve 7 shown in Fig. 3. Referring to this figure, the line a-b of the curve 7 indicates the magnitude of the current in the winding of relay D when cam member B is at rest. When the circuit for reactance C and relay D is first opened, due to the cam follower A leaving the surface of cam member B, the current in the winding of relay D will fall along the line b-c. When this circuit is next reestablished by the cam follower reengagmg the cam member, the current in the winding of relay D will .build up along the.

line cb It will be obvious that the final value of the current in the winding of relay D will depend upon the time during which cam follower A remains in engagement with cam member B. The next succeeding revolution of cam member B will cause the current in the winding of relay D to trace the line b -c b etc.

It will be seen that if relay D is constructed to have a pick-up value as indicated by the line 8 in Fig. 3, and a release value as indicated by the line 9, relay D will remain picked up, and hence will hold its front contact 6 closed, as long as cam member B rotates below a predetermined speed.

Referring now to Fig. 4, I have here shown a curve 10 which indicates the growth and decay of the current in the winding of relay D when the cam member B is rotated at a relatively high speed. It will be noted from an inspection of this curye that the open circuit interval during which the current in the winding of relay D is decreasing, is the same length as when the cam member B was rotating at the slower speed, but that the closed circuit interval is considerably shorter. It will also be noted, that the current in the winding of relay D never reaches the value at which this relay will pick up and close its front contact.

It follows from the foregoing that by properly selecting the electrical and mechanical characteristics of the elements of the apparatus, it is possible to cause relay D to open and close its front contact 6 at any desired speed of rotation of cam member B.

Referring now to Fig. 5, the curve 11 here shown indicates the variation which takes place in the maximum or peak value of the current in the winding of relay D as the speed of rotation of cam member B varies, and the curve 12 indicates the variation in the minimum value of the current in the winding of relay D as the speed of rotation of cam member B varies. From an inspection of these curves, it will be seen that if it is desired to have the relay operate its contact at a certain definite speed of rotation of cam member B, this result may be accomplished by constructing the relay in such manner that at the desired speed, its pick-up and release values will fall on these curves. For example, assuming that it is desired to have relay D operate its contact at the speed indicated by the vertical line 13 in Fig. 5, this may be done by constructing relay D to have pick-up and release values corresponding to the points where line 13'crosses the curves 11 and 12.

Relay D may be utilized to control any suitable electro-responsive device in such manner that the device will occupy one condition when this relay is energized, and another condition when this relay is deenergized. For example, if the apparatus is mounted on a locomotive in such manner that the'speed of rotation of cam member B varies with the'linear speed of the locomotive, relay D may be utilized to control a speed governing device for the locomotive.

As here shown, relay D controls a brake controlling magnet E which applies the brakes on the locomotive when this magnet becomes deenergized. The circuit for magnet E is carried over front contact 6 of relay D and it will be apparent, therefore, from the foregoing, that as long as the speed of the locomotive is below some predetermined speed, magnet E will be energized, but that if the speed of the locomotive increases beyond this speed, magnet E will-become deenergized, thus enforcing a low speed limit on the locomotive. It should be definitely understood, however, that apparatus embodying my'invention is in no way limited to this particular use.

Referring now again to Fig. 1, it should be pointed out that if the cam member B is connected to a device which may rotate in either direction, such for example, as a reversible motor, the connection between the motor and the cam member will be so designed that the cam member will rotate in the same direction for either direction of rotation of the motor.

Under some conditions, it is undesirable,-

to carry the circuit for reactance C and relay D through cam member B. When this'is the case, the apparatus may be constructed in the manner illustrated in Fig. 2. As here shown, an inertia member AA, the mass of which is determined largely by the mass of an integral cylinder M, 'is pivotally mounted for rotation about a suitable pivot indicated at 14 in the drawing, the pivot 14 being concentric with the axes of the cylinder M. The inertia member AA is connected with the cam follower A by a spring T which constantly urges the inertia member toward the position in which a contact finger 15 attached to the right-hand end of the inertia member engages a contact member 16 attached to the cam follower A. The circuit for relay D as here shown, is from terminal X, through inertia member AA, contact 15-16, cam follower A, and then as previously described in connection with Fig. 1, to terminal Y.

With the apparatus constructed in the manner shown in Fig. 2, each time the radial portion 2 of the cam member B passes the end of the cam follower A, a cam follower will leave the surface'of the cam member for a fixed interval of time in the manner previously described. When the cam follower leaves the surface of the cam member, the spring T will become stressed and will exert a downward pull on the inertia member AA but due to the inertia of the inertia member, the. inertia member will lag behind for a fixed interval of time, and during this interval of time, contact 1516 will be open. By properly proportioning the mass ofthe inertia member AA, the tension of spring T, the mass of cam follower A, and the tension of spring S, the contact 15-16 may be made-to open and close the circuit for reactance C and relay D in substantially I the same manner as cam follower A and cam member B interrupted this circuit in Fig.

1. The operation of the electrical portion be obtained without this reactance by constructing relay D to have a reactance which is the equivalent of the combined reactance of reactance C and its own winding.

Although I have herein shown and de-,

by the body for periodically interrupting an electrical circuit for substantially uniform intervals which recur at a frequency which varies with the speed of the body, an electro-responsive indicating device, an electrical circuit controlled by said means and including said indicating device, and an asymmetric unit connected in multiple with said device.

2. Apparatus for indicating the speed of a movable body comprising means controlled by the body for periodically interrupting an electrical circuit for substantially uniform intervals which recur at a frequency which varies with the speed of the body, an electroresponsive indicating device, a reactance; an electrical circuit including said means, said indicating device and said reactance, and an asymmetric unit connected across said reactance and said electro-responsive device in said circuit.

3. Speed responsive apparatus comprising a rotatable cam member of electrical con ducting material, a cam follower of electrical conducting material biased into engagement with said cam member, said cam member and said cam follower being so constructed that said follower will move out of engagement with said cam member for a substantially fixed interval of time during each revolution of said camimember, an electroresponsive indicating device, an electrical circuit for said device including said cam member and said cam follower, and an asymmetric unit connected in multiple with said device in said circuit.

4. Speed responsive apparatus comprising a rotatable cam member of electrical conducting material, a cam follower of electrical conducting material biased into engagement with said cam member, said cam member and said cam follower being so constructed that said follower will move out of engagement with said cam member for a substantially fixed interval of time during each revolution of said cam member. an electro-responsive indicating device, and an inductive electrical circuit for said device controlled by the contact formed by said cam member and said cam follower.

5. Speed responsive apparatus comprising a rotatable cam member of electrical conducting material, a cam follower of electrical conducting material biased into engagement 6 with said cam member, said cam member and said cam follower being so constructed that said follower will move out of engagement with said cam member for a substantially fixed interval of time during each rev- 10 olution of said cam member, an electro-responsive indicating device, means controlled by said cam member and said cam follower for supplying current to said device, and an asymmetric unit connected across said device.

6. Speed responsive apparatus comprising a rotatable cam member of electrical conducting material, a cam follower pf electrical conducting material biased into engage ment with said cam member, said cam mem- 2 ber and said cam follower being so constructed that said follower will move out of engagement with said cam member for a substantially fixed interval of time during each revolution of said cam member, an electroresponsive indicating device, a reactance; an electrical circuit including said cam follower, said cam member, said indicating device, and said reactance, and an asymmetric unit connected in multiple with said reactance and said indicating device in series in said circuit.

7. Speed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower biased into engagement with said cam member, an electro-responsive indicating device, an asymmetric unit, and means controlled by said cam member and said cam follower for supplying to said device and said asymmetric unit connected in multiple current which is periodically interrupted for substantially uniform intervals which recur at a frequency which varies with the s eed of rotation of the cam member, 45 8. peed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower, means for biasing said cam follower into engagement with said cam member, a relay, a reactance, an asymmetric unit, a closed circuit formed by said asymmetric unit connected in multiple with said relay and said reactance in series, and means controlled by said cam member and said cam follower for supplying to said closed circuit current which is periodically interrupted for substantially uniform intervals which recur at a frequency which varies with the speed of rotation of said cam member. 3

9. Speed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower, means for biasing said cam fol- 65 lower into engagement with said cam memcircuit current the magnitude of which is periodically decreased for substantially uniform intervals which recur at a frequency which varies with the speed of the body.

10. Speed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower, means for biasing said cam follower into engagement with said cam member, a contact member attached to said cam follower, a spring, a pivoted inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, a relay, and an inductive cir-. cuit for said relay controlled by the contact formed b said fixed contact and said contact mem er.

11. Speed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower, means for biasing said cam follower into engagement with said cam member, a contact member attached to said cam follower, a spring, a pivoted inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, a relay, an asymmetric unit, and means controlled by the contact formed by said contact linger and said contact member for supplying current to said relay and said asymmetric unit connected in multiple.

12. Speed responsive apparatus comprising an oscillating member, an inertia member operativzly connected with said oscillating member, a contact controlled by said oscillating member and said inertia member, an asymmetric unit; an electro-responsive device, and a circuit controlled by said contact and including said asymmetric unit and said device connected in multiple.

13. Speed responsive apparatus comprising an oscillating member, an inertia member operatively connected with said oscillating member, a contact controlled by said oscillating member and said inertia member, a reactance, an asymmetric unit, an electroresponsive device, and a circuit controlled by said contact and including said asymmetric unit connected in multiple with said reactance and said electro-responsive device connected in series. V

14. Apparatus for indicating the speed of a body comprising a member which is oscillated at a speed which is proportional to the speed of the body, a contact member carried by said oscillated member, a spring, an inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, and an electro-responsive device controlled by the contact formed by said contact finger and said contact member.

15. Apparatus for indicating the speed of a body comprising a member which is oscillated at a speed which is proportional to the speed of the body, a contact member carried by said oscillated member, a spring, an inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, an electroresponsive device, an asymmetric unit, and a circuit controlled by the contact formed by said contact finger and said contact member and including said asymmetric unit and said electro-responsive device connected in multiple.

16. Apparatus for indicating the speed of a body comprising a memper which is oscillated at a speed which is proportional to the speed of the body, acontact member carried by said oscillated member, a spring, an inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, an electroresponsive device, an asymmetric unit, a reactance, and a circuit controlled by the contact formed by said, contact finger and said contact member and including said asymmetric unit connected in multiple with said reactance and said electro-responsive device connected in series.

17. Speed responsive apparatus comprising a rotatable cam member substantially in the form of a portion of a spiral, a cam follower, means for biasing said cam follower into engagement with said cam member, a contact member attached to said cam follower, a spring, a pivoted inertia member provided with a contact finger and biased by means of said spring to the position in which said contact finger engages said contact member, a relay, a reactance, an. asymmetric unit, and means controlled by said contact finger and said contact member for supplying current to a closed circuit including said asymmetric unit connected in multiple with said reactance and said relay connected in series.

18. Apparatus for controlling the speed of a movable body comprising a contact, means connected with the body for controlling said contact in such manner that when the body'is at rest in any position the contact will be closed but that when the body is moving said contact will become periodicallyopened for substantially uniform intervals which recur at a frequency which varies with the speed of the body, an

means connected with the body for controlling said contact in such manner that when the body is at rest in any position the contact will be closed but that when the body is moving said contact will become periodically opened for substantially uniform intervals which recur at a frequency which varies with the speed of the body, an electro-responsive device, an electrical circuit controlled by said contact and including said device, an asymmetric unit connected in multiple with said device and means for controlling the speed of said body controlled by said device.

20. Apparatus for controlling the speed of a movable body comprising a contact, means connected with the body for controlling said contact in such manner that when the body is at rest in any position the contact will be closed but that when the body is moving said contact will become periodically opened for substantially uniform intervals which recur at a frequency which varies with the speed of the body, an electro-responsive device, a reactance; an electrical circuit including said contact, said electro-responsive device, and said reactance; an asymmetric unit connected across said reactance and said electro-responsive device in said circuit, and means for controlling the speed of said body controlled by said device.

21. Apparatus for controlling the speed of a vehicle comprising a contact, means connected with the vehicle for controlling said contact in such manner that when the. vehicle is at rest in any position said con tact will be closed but that whenthe vehicle is moving said contact will become periodically opened for substantially uniform intervals which recur at a frequency. which varies with the speed of the vehicle, a relay adjusted to release its armature when the average value of the current in its winding decreases below a predetermined value, an electrical circuit controlled by said contact and including the winding of said relay, and a brake controlling magnet for the vehicle controlled by a front contact of said relay.

22. Apparatus for controlling the speed of a vehicle comprising a contact, means connected with the vehicle for controlling said contact in such manner that when the vehicle is at rest in any position said contact will be closed but that when the vehicle is moving said contact will become periodically opened for substantially uniform intervals which recur at afrequency which varies with the speed of the vehicle, a relay adjusted to release its armature when the average value of the current in its winding decreases below a predetermined value, an electrical circuit controlled by said contact and including the winding of said relay, an asymmetric unit connected in multiple with the winding of said relay, and a brake controlling magnet for the vehicle controlled by a front contact of said relay.

23. Apparatus for controlling the speed of a vehicle comprising a contact, means connected with the vehicle for controlling said contact in such manner that when the vehicle is at rest in any position said contact will be closed but that when the vehicle is moving said contact will become periodically opened for substantially uniform intervals which recur at a frequency which varies with the speed of the vehicle, a relay adjusted to release its armature when the average value of the current in its winding decreases below a predetermined value, a reactance; an electrical circuit including said contact, the winding of said relay, and said reactance; an asymmetric unit connected across said reactance and the winding of said relay in said circuit, and a brake controlling magnet for the vehicle controlled by a front contact of said relay.

In testimony whereof I aflix my signature.

FRANK H. NICHOLSON.

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