US2255092A - Rotational speed responsive device - Google Patents

Description

Sept. 9, 1941.

M. T. WINTSCH 2,255,092 ROTATIONAL SPEED RESPONSIVE DEVICE Filed Sept. '7, 1938 I 2 Sheets-Sheet 2 Patented Sept. 9, 1941 ROTATIONAL SPEED BESPONSIVE DEVICE Max Theodore Wintsch, Lancaster, Pa., of one-half to Newton M. Weaver,

asslgnor Lancaster,

Application September 7, 1938, Serial No. 228,843

7 Claims.

- This invention relates to a rotational speed responsive device and more particularly to a device for'indicating the speed of rotational bodies and for controlling the speed of operation thereof. 7

My invention contemplates an electrical system for rotational speed indication and/or control in which an electrical relay, responsive only to current of a predetermined frequency or frequencies, is effective for controlling the initiation of a signal and/or a control device, said relay being tuned so as to resonate at such predetermined frequency and being electrically connected to a variable reactance which is periodically varied by altering its field of magnetic flux,- preferably by periodically introducing into itsmagnetic field ferrous metal, such as wrought iron armature pieces, whereby the current flow in a winding of said reactance is periodically increased and decreased, the lines of force or magnetic flux being greatly increased as the ferrous metal armature pieces approach the magnetic held between the pole pieces of the reactance,

reaching a-maximum point when an armature piece is in axial alignment with the reactance core pole pieces, and decreasing as the armature pieces move out of the magnetic field. The means for introducing such armature pieces into tion for a predetermined interval, for permanently interrupting such circuit, until said latch position, thus rendering the signal and/or conthe field of the reactance core, and thus varying the reactance of said core and its winding, is

, connected to the apparatus, the rotational speed of which is to be indicated and/or controlled.

A variable reactance suitable for the purpose may comprise a permanent magnet, preferably formed of cast Alnico, having a pair of operatng coils connected in series and mounted on to the two pole pieces of the magnet, and a nonmagnetic disk carrying uniformly spaced armature pieces, preferably also formed of Alnico" or iron. If desired, a magnetizable metal core may be-provided having an energizing field coil positioned thereabout, instead of a magnet.

My invention also contemplates, but in a somewhat more limited sense, a system in which there is provided a slow release relay controlled by a tuned master relay, which slow release relay is effective for initiating a control upon the operation of said master relay for a predetermined interval. This unit preferably comprises a slow release relay, as previously mentloned, and a mechanical latching arrangement effective for no mally holding the low voltage ignition system in closed circuit, if used on an internal combustion engine, but effective, upon deenergizatrol inoperative, so that in the event of failure of the apparatus to properly function, either by reason of the rotational speed of the machine decreasing below or increasing above the prescribed range, or by reason of failure of the electrical system, the signal and/or controlwill be initiated. This type of speed control device is well suited for use in place of the usual mechanical centrifugal speed governors in any industrial application.

It will become apparent that my invention contemplates other features and combinations, as the detailed description thereof is considered in conjunction with the attached drawings, in which: a

Figure l is a schematic diagram illustrating the apparatus of my invention in a preferred form for use on an automobile or other internal combustion engine, for example;

permanent.

Figure 2 is a similar view showing a modification of my invention designed primarily for steam or air propelled rotational bodies and incorporating an appropriate control for the braking or propelling fluid; and

Figure 3 is a similar view illustrating an embodiment of my invention in which a multi-reed relay is employed for rotational speedcontrol, as employed on an electrically propelled engine for example.

Referring first to'Figure 1, there is provided a master relay 2 which is tuned by a condenser *3 connected across the operating winding thereof. The relay 2 and condenser 3 form part of a tuned circuit including reactor 4 and an adjustable resistance 5. The reactor 4 comprises an Alnlco permanent magnet 6 having armature coils l and 8 surrounding poles 9 and I0, 'respectively, cast integral with the magnet 6. The coils 1 and I are connected in series by wire H.

The other side of coil 1 is connected by wire I! to the sliding contact H of adjustable resistor 8, which resistor is connected by wire I 4 toone side of the coil of master relay 2. Likewise, wire I connects the coil '8 with the other side of the coil of master relay 2, condenser 3 bridging the wires l4 and I5. This provides a tuned circuit including the relay 2, condenser 3, and resistor 5 which circuit is periodically energizedwhen the and coils 1 and 8, the capacity of the condenser reactance is varied. The windings on the relay 2 3, and the-- value of resistance 5 are pre'determined and set so that the entire circuit will resonate only when current of a predetermined frequency flows therethrough.

The air gap between pole pieces 9' and i0 is 24 to its current source and 'efiecting illumination thereof.

In Figure 1, there is shown, in addition to the signal 24, a control relay 2! which is energized when armature 18 of master relay 2 is in open position and in contact with back point of contact 28 as shown. Relay 2'I has slow release characteristics such that it must remain deen-' ergized for a predetermined period of time, say three seconds, before itsarmature will fall.

In the embodiment shown in Figure 1, lead 28 connects directly from battery 2i to the primary ignition circuit C and lead 30 connects from the other side of the battery 2|, through switch 26 and wire 25 to front point of contact 3i of control relay 2i. The circuit for the primary ignition circuit C is completed through armature 32 of control relay 2?, the other front point of increased lines of magnetic flux to pass more readily therebetween, with concomitant increase of the amplitude of the current passing through the tuned relay circuit. As the armature pieces I I progressively move away from the opposed pieces 9 and l0,"thus increasing the air gap therebetween, there is a gradual diminution of current flow. It will be apparent, therefore, that as the armature pieces II progressively approach and recede from the gap between the pole pieces 9 and I0, there is built up a frequency of current, which, when it reaches the point of resonancefor which the circuit is tuned, will energize relay 2, causing it to lift its armature it.

For purposes of illustration, let it be assumed that with the standard automobile speedometer cable driving the disk It through its driving shaft tact 28, armature l8, and wire 22.

I9 a speed of movement of the vehicle of miles per hour will efiect revolution of the cable and shaft l9 at the rate of 750 revolutions per minute and let it be further assumed that disk l6 carries four ,equally spaced armature pieces I1. With such hypothetical basis, the circuit including the relay 2, condenser 3, reactor 4, and resistor 5 would be so tuned and adjusted to resonate at 50 cycles per second. (The rotation of the disk lSat 750 revolutions per minute; would effect afrequency of 3000 cycles per minute or 50 cycles per second.)

When the speed of disk iS-reaches 750 revolutions per minute, and the circuit is in resonance, relay 2 will be energized and its armature i8 lifted into engagement with front point of contact 20, (the relay 2 is shown in'deener'gized position in Figure 1 and current will flow from a battery 2|, through/wire 22 connected to armatrue It, front point of contact 20, and through wire 23 connected to a signal light 26, the other side or the light 2.4 being permanently connected to the other side of the battery 2 5, through wire 25, when switch 26 is closed.

' From the foregoing, it will be clear that when the apparatus, the rotational speed of which ,'is

to be indicated and/or controlled is not in rotation or has not attained a predetermined speed,

relay 2 will not be energized and consequently signal light-24 will not be illuminated, but that, immediately the speed of rotation reachesa predetermined point, resonance will be established in the circuit causing the master relay 2 to lift its armature. l8 and thus connecting signal light 21 is energized, current is fed to the primary ignition circuit C.

In the event the maximum speed of rotation be reached, lifting armature l8, thus deenergizing control relay 21, and such speed be maintained for a predetermined time, concomitantly causing control relay 2? to be deenergized for a time period longer than its time lag, armature 32 will fall, being latched against return by latch 37 positioned in the path of travel thereof. Upon release of armature 32 from its closed position, the supply of current for the primary ignition circuit C will fail and the enginewill be stopped. a

The latch 31 is preferably so positioned that thevehicle operator cannot conveniently hold it against operation. If the apparatus be directly interconnected with the speedometer drive 50; cable under the dash board this 'will insure that the operator will bring the car to a complete stop to reset the latch 31 and thus permit closing of the primary ignition circuit. This will efiectively aid in the apprehension of code violators and thieves since, if pursued by'an oficer, it will-be impossible to exceed a predetermined speed, say 50 miles per hour, without the control relay becoming deenergized and locking the primary ignition system out of operation until switch 3? is manually reset. In Figure 2,I have shown a similar circuit but here there is employed a tuned reed relay and a somewhat diiferent control. This particular apparatus is suited for use on mobile or stationary engines employing fluid propulsion, such as steam, water, or air, or fluid braking.

In thebasic principles, the system of Figure 2 is the same as the device of Figure'l. It includes a tuned reed master relayed which has a tuning condenser'eii connected across its operating winding 60. Like the circuit shown in Figure 1, master relay 38 constitutes part or a resonant circuit including -a variable reactance al, the

series coils 42 and 43. of'which are connected in closed circuit with the operating coil 40 of If a six volt light be used, rotation of the disk the master relay ll by wires 44 and 4!. The

' necessary.

When reed 49 is caused to vibrate by reason oi the attainment of resonance in the tuned circuit effected by rotation of the rotatable disk of reactor 4| at a predetermined speed, contact 41 or reed 49 will be vibrated into and out of engagement with contact point 48 in accordance with the frequency vibration natural to the reed 46. When contact 41 is in engagement with contact point 49, current for the operating winding of a control relay 49 is fed from a motor generator set 50, through contact point 48, contact "I, reed 48 and a wire II which connects with the mounting for the reed 48. The other sideoi the operating winding of relay 49 is normally connected through wire 51 and switch it to the other side of the motor generator 56.

Thus, it will be apparent that relay 49 is normally deenergized, but is energized when the circuit including the operating winding 49 of master relay 38 is in. resonance.

When relay 49 is deenergized, its armature 54 lies in open position in engagement with back points of contact 55 and 56 which are eiiective for connecting one side of high voltage supply S with a solenoid type fluid control valve through lead B, contact 56, armature 5t, contact 58 and lead 59. The other side of the operating winding, for the control valve 5'! is normally connected to the source 3 through lead 56..

The valve 51 normally holds the supply pipe SE for fluid, either for propulsion or braking, closed so that the fluid is eflective for causing rotation of the apparatus or for holding the brakes against operation. When master relay 3B is energized however, the relay 43 is also energized, lifting armature H and interrupting the flow or current to control valve 91, the fluid pressure will cause valve 5? to open and the fluid will be exhausted to atmosphere through a whistle 62, and at the same time, either slowing down or stopping the apparatus or applying the braking mechanism When master relay 38 is energized by reasons of the speed or rotation of the disk of reactance 4i effecting resonance in its circuit, the armature 54 of relay 49 will rise (by reason of current flow thereto from motor generator 50) into engagement with front points of contact 63 and 6B, thus connecting signal light 65 with wire 60 from source 8 through wire 65, front point of contact 54, armature 94, front point of contact 53 and wire 9?. The signal light 65 is connected permanently to the other side orthe source S by wire Slit If desired, a "neon pilot light 69 may be provided which is connected across the leads 44 and This light will be illuminated whenithe reactance disk is in rotation at a speed suiiicient to eii'ect a flow of current -in the circuit including the neon light and thus illuminate the, same.

at low speed will result in its illumination.

In the system shown in Figur 3, there is ,provided a minimum and maximum rotational speed ing a laminated magnetizable core. As in the embodiment shown in Figure 2, there is provided a vibrating reed relay generally indicated by the numeral 19. This relay is provided with a pair of energizing coils Ii and 12 connected in series by wire 13. The relay has a tuning condenser I4 connected across the windings of coils H --12.

v The variable reactance designated generally by the numeral 15 includes a pair of operating coils l6 and IT whichare positioned around the legs of an, electromagnet 18 which is energized by a field coil "connected to a direct current motor generator set 90 by wires 8| and 92. The operating coils I5 and 11 are connected in series by wire 93 and they constitute a part of a tuned circuit including coils ll and 12, the latter of which is connected by lead 84 to condenser 14, also forming part of, the'tuned circuit. Coilfli v is connected to condenser 14 by lead 85 and coil control. device in combination with an indicating signal. Also, in this embodiment, there is Dro- I1 is connected by lead to the co pleting the circuit, I

The relay I9 is provided with a plurality of individual reeds B'i-ln the embodiment illustrated there being 9-e ach of which isrconnected to a common bar 89 and each being adjusted for natu 1| comural vibration at a predetermined frequency, the

group as a whole being adjusted to vibrate within a prescribed range of frequencies predetermined in accordance with the range of rotational speed desired. The reeds 91 make contact, when in vi bration, with a common contact bar i I When any of the reeds El in vi ation, an consequently making contact with hair 2, or. rent will. how to control; relay 5% from the motor generator Bil, through lead connected to one side of the generator it and lead at connecting lead M with bar 89. Current wfil flow through the reed or reeds 8! which happen to be in vibration and thence through common connecting bar 88 to a wire 93 which leads to control relay 9@. The other side of the motor generator at is normally connected to the relay Si! by a connecting wire 99, joining with the common lead 3 E.

,It will be observed, therefore, whenever master relay Ill is in operation, control relay 862 will likewise be energized, regardless of the particular reed or reeds 8? of master relay ill which are in vibration. The relay 89 shown in deenergized position in Figure When relay so is energized, its armature 95 will he brought into enga ement with back points of contact 98 S'l', thug closing the circuit for the holding coil 98 for the circuit breaker it one be employed, and for also closing the circuit for the solenoid of an electro-pneumatic valve 99. the holding coil 98 is from motor generator to through lead 9i to bacl: point of contact 3i", through armature 95 to "each point of contact 96 which connects through wire iflil to the holding coil St. The other side of the coil is normally connected to the motor generator 86 through common lead M, The circuit for the solenoid coil of the valve 99 is the same, a lead llli connected to the coil being also connected with lead I00 from back point of contact 96 of relay 9B.

The electro-pneumatic valve 99 is normally held closed whengits coil is energized but is opened by the fluid, which may be steam or air, passing through conduit I02 and if desired a whistle 13 -may be provided in this line which will be sounded when valve 99 is deenergized, such sounding being effected by means of the exhausting steam or air passing therethrough from conduit I02.

When relay 99 is deenergized-that is when none of the reeds 81 is in vibration-its armature exists in the tuned circuit.

95 will fallinto engagement with front points of contact I 04 and I05thus completing the circuit for a warning signal light I which is then connected to the motor generator through common lead 8|, lead I01, front point of contact I04, armature 95, front point of contact I and lead I00. The other side of the light is connected by a wire I09 to the common lead 9I which connects with the motor generator 80.

Since the control relay 90 is effective for shutting down the machine when speeds below, as

. common lead 91 from motor generator 90,

through wires III and H2. As previously pointed out common lead 8I is normally connected to the other side of the solenoid 99 and holding coil 98.

For purposes of illustration,it will be assumed that the rotational speed is to be controlled between limits of 375 and 600 revolutions per minute and that,the rotating disk of the variable reactor is connected through its shaft to rotate at the samespeed as the apparatus to which it is connected and the speedof which is to be indicated and/or controlled, and further, it will be assumed that the rotating disk of reactor 15 is provided with four armature pieces 9. Under such conditions, when a speed of' 375 R. P. M. is attained by the apparatus, the current flowing in the tuned circuit including the coils II-J2, condenser and coils I6 and I1 will have a frequency of cycles and the first reed of the series, 81a, will be adjusted to vibrate at about that frequency. When a speed of 600 R. P. M. is attained by the apparatus the frequency in the circuit will be 40 cycles and accordingly reed 87b should be adjusted to vibrate at about that frequency, and the seven intermediate reeds should be adjusted to vibrate within the range between 25 to 40 cycles so that at least one of the reeds will be in vibration at all times when the speed of rotation of the apparatus is such that afrequency between the range of, 25 and 40 cycles If desired, a pilot light II l may beprovided connected by leads I I5 and II 6 across the coils I6 and 11 of the variable reactance I5 and this the speed of rotation of the apparatus continues within the prescribed range (between 375 and 600 R. P. M.) the functioning of the device will remain unchanged, excepting that various of the reeds 87 may from time to time be in vibration. In the event, however, a speed below or above the prescribed range obtains, then thetuned circuit will be out of resonance with any of the reeds and none will vibrate thus opening the circuit for control relay 90, whereupon valve 99 will be deenergized and the control fluid will be exhausted through warning whistle I03 and the brakes will be applied or the supply of propelling current will be disrupted. Light I06 will beenergized and holding coil 98 will be deenergized,

, if the vehicle be electrically propelled, permitting the circuit breaker which it controls to fall and thus interrupt the supply of propelling current for the vehicle.

The group of reeds disposed in the vicinity of reed 81a may be used to control an electro-valve similar to the valve 99 effective to increase the supply of operating power and thus increasing the speed of rotation of the machine and the group of reeds disposed adjacent reed 91b may be used to control a second valve disposed so as v to operate in a manner similar to valve 99 initiating a warning signal and cutting off the supply of operating power so as to reduce the speed of rotation to within the prescribed limits. While I have described and illustrated certain preferred embodimentsof my invention it will be understood that the same is not so limited but may be otherwise embodied and practiced within the scope of the following claims.

I claim:

1. A rotational speed responsive device com prising in combination a tuned relay, a variable reactance connected in series with said relay, means for producing a current which varies in accordance with the variations of the reactance, said relay being responsive only to current of a predetermined frequency established by said reactance, a source of current, and a slow release relay effective for interrupting the supply of current from said source upon energization of said first mentioned relay for a predetermined interval greater than the time lag of said slow release relay.

pilot light H4 will be illuminated whenever current is flowing in the tuned circuit and will indicate proper'functioning of the variable reactor circuit.

The operation of the device shown in Figure 3 will be briefly described in order to insure clarity of understanding of the invention. The machine operator presses button IIO which effects enerin the tuned circuit will increase until the mini-' mum speed of 3'75 R. P. M. is reached at which time reed 81a will vibrate and control relay 90 will become energized extinguishing the light I06 which will give the operator an indication that minimum speed hasbeen attained and that the starting button IIO-may be released. So long as ing of said relay into resonance, an electro-pneumatic valve for controlling said apparatus and a control relay effective for deenergizing said electro-pneumatic valve upon energization of said read relay.

3. A rotational speed responsive device comprising in combination a reed relay including a' plurality of reeds having natural periods of vibration in a prescribed range, a reactance connected in series with said relay, means for tuning said relay, a control relay effective upon energization for completing an electrical circuit, saidv reactance being connected to the apparatus the rotational speed of which is to govern the operation of said device, the plurality'of said reeds engaging a common contact bar and effective for energization of said control relay within said prescribed range of frequency induced by said reactance device.

4. A rotational speed responsive device comprising in combination a reed relay including a plurality of reeds having natural periods of vibration within a prescribed frequency range and eitective when in vibration for contact with a common contact bar, a variable reactance connected to the apparatus, the rotational speed of which is to govern the operation of said device, and electrically connected in series with said relay, means for timing said relay, eaid reactance being effective for bringing the circuit including its operating winding and the operating winding of said reed relay into resonance within said prescribed frequency range. and electrical means connected in circuit through said bar when at least one of said needs is in vibration.

5. A rotational speed responsive device comprising in combination a tuned relay, a variable reactance connected in series with said relay, means for producing a current which varies in accordance with the variations of the reactance,

said relay being responsive only to current of a predetermined frequency established by said reactance a source or current, a slow release relay effective for interrupting the supply of current from said source upon energization of said first mentioned aeay for a predetermined interval greater than the time lag of said slow release relay and means ior'latching said slow release relay in open position.

6. A rotational speed responsive device comprising in combination a tuned relay, a variable reactance connected in series with said relay. means for producing a current which varies in accordance with the variations of the reactance, said relay being responsive only to current of a predetermined frequency established by said reactance, a source of current, and a time lag relay eflective forinterrupting the supply of current from said source upon energization of said first mentioned relay for a predetermined intervalgreaterthanthetimelagofsaidtimelag 7. A rotational speed responsive device comprising in combination a reed relay including a plurality of reeds having natural periods of vibration within a prescribed frequency range and effective when in vibration tor-contact with a common contact bar, a variable reactance connected to apparatus, the rotational speed 0! which is to govern the operation or said device and electrically connected in series with said relay, means for tuning said relay, said reactance being eflective for bringing the circuit including its operating winding and the operating winding of said reed relay into resonance within said prescribed irequency range, and a control relay connected in circuit through said bar when at least one otsaidreedsisinvibration.

MAX THEODORE WINTSCH.

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