US2519801A - Governor - Google Patents

Description

Aug. 22, 1950 v T. TOGNOLA GOVERNOR Filed May 1, 194a u ll! 7 w 1 w? Mw JINVENTOR w b W BY ATTORNEY u l i Patented Aug. 22, 1950 GOVERNOR Tullio Tognola, Sidney, N. Y., assignmto Bendix Aviation Corporation, New York, N. Y., a corporation of Delaware Application May 1, 1946, Serial No. 666,464

16 Claims.

This invention relates to a governor adapted to stop an internal combustion engine at a predetermined speed. The device is adapted to stop the engine by grounding its current supply. It will be described in connection with the grounding of a magneto primary circuit, but it is to be understood that this particular description is for illustrative purposes and not for purposes of limitation.

Many internal combustion engines, of both stationary and movable type, are ignited by magnetos. Magnetos operate at a speed proportional to the speed of the engine, their sparking rate increasing as the rate of firing of the engine increases. Such engines are frequently operated inadvertently or by design at ineiiicient or even dangerous speeds. It is desirable that such engines should be controlled by a governor capable of stopping the engine when it exceeds a selected speed. Devices of some complexity have heretofore been made to achieve this purpose, but it is believed that no satisfactory governor has yet been produced that is adapted to instant application to any magneto-fired engine with out tools more complex than a screw driver.

It is an object of this invention to develop a short circuiting device adapted to stop an internal combustion engine at a predetermined speed.

Another object of the invention is to develop a governor that will be operative whenever the engine is in operation, but which will not interfere with the operation of the magneto or decrease its efficiency as long as the engine is operating within the selected speed range.

Another object of the invention is to make a self-contained governor unit that may be connected with ease to an internal combustion engine and which will, when so applied, function with a maximum of efficiency.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for purposes of illustration only and is not intended as a definition of the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

The drawing shows diagrammatically a magneto with the governor attached thereto. In the drawing, a magneto box or casing Ill contains a magneto of which the secondary It, the primary [2, a condenser IS, a breaker J4, and a 2 ground I5 are diagrammatically shown. The magneto circuit thus diagrammed is conventional.

In order to put the magneto in position for starting, a switch box IE containing a switch I! is provided. When the switch element I! is thrown into contact with switch element I8, the primary of the magneto is grounded through ground I9 so that no current is generated in the secondary H and the engine cannot run. When the switch I! is open as indicated in the drawing, a conductor 20 connects the magneto with the switch and a conductor 2| within the cable 22 connects the switch with the governor, and current is generated in the secondary H, operating the engine.

The cable 22 and the connections thereof constitute a portion of the invention. The core of the cable 22 is a conductor 2i which is preferably made of copper or other wire of good conductivity, which is encased in flexible insulating material of any satisfactory type. The insulating material is surrounded by a conductive sheath or shield 25 which may well be of flexible metal mesh. That protective metal shield is attached at one end 23 to the box 24 that preferably encloses the governor. The box is metal, or it is provided with a conductor to which the cable covering is attached. It will be considered in the further description of this invention that the box is of metal and that the flexible metallic sheath of the cable is attached thereto. At its other end the cable sheath is provided with a connector 26 which is attached to the metallic box ii that houses the switch. In this case also, the box need not be metallic so long as a conductive means is provided between the connection 26 and the ground l9. It will be considered in the further description of the invention that the box IE is metal and that it is connected at 21 to the ground 19.

The function of the operative parts of the governor is to connect the magneto primary [2 through conductors 20 and 21 to box 24, and through cable sheath 25 to the ground at [9. While the engine is operating within its permitted speed range, no such connection is made and the magneto continues to function, but when the speed of the engine exceeds a, predetermined value the connection is made between conductor 2| and sheath 25 and the magneto primary is grounded, stopping the engine. This is accomplished by means of a relay having a coil 30, an armature 3i, and an armature contact 32 which is connected by conductor 33 to the box 24. When the relay coil 30 is energized the contact 34 on the arm 3| closes with contact 32 completing the connection between the conductor 2| and the ground 19 and stopping the engine. The contact 32 is itself a magnet which may be of permanent or electro character. Alternatively, a mechanical catch may be employed to hold the armature 3| in grounding position, dispensing with the use of a magnet at 32.

In the form of the invention which is bein described, it is desired to stop the engine completely until the governor has been reset. Therefore, a resetting button 35 which must be operated by hand is provided for the disengagement of relay arm 3| from contact 32,-or' for the releasing of a mechanical catch.

A particular problem arises in connection with such a device which because it must be continually in operative connection with the magneto, tends to bleed the primary of current necessary to the proper generation of a high tension current in the secondary. That problem has been solved in a noveland successful manner. Referring again to the drawing it will be observed that the conductor 2| is joined to a conductor 40 which feeds the primary 4| of a transformer 42. The primary is connected through conductor 43 to ground through the box at 44. The secondary 45 of the transformer 42 has a center tap 46 which is connected to the conductor 41 and to ground. The ends ofthe secondary coil are connected to a full wave rectifier 48 which is in turn. connected to a conductor 49. A fully rectified current is therefore supplied by the secondary and the rectifier tubes to the governor circuit. A

condenser 50 is connected across the conductors 41 and 49. The relay coil 30 and the main path of a strobotron tube 5| are in the main governor circuit and are in parallel with the condenser 50. Also in parallel with the relay and the main circuit of the strobotron are three resistances 52, 53, 54 of which 53 is variable and is preferably a potentiometer. These resistances are of graduated value, 52 being preferably of least resistance. 54' of larger, and 53 selectively of greatest resistance.

If desired the ground connection through cable 22 can be omitted, the box 24 being grounded at 44, but this requires two ground connections, one at I 9 and one at 44, which is not always desirable.

The inductance of coil 4| is high compared to that of coil l2, being on the order of 3-5 mh. to .75 h., so that it does not affect the operation of the magneto by draining current from the primary. When the 'engine is operating within its preselected speed range, a very minor amount of current passes through lines 20, 2|, and 40 to the transformer primary 4| which is duly rectifled by the rectifier 48. The voltage drop between line 58 and line 41 is determined by the current flow and the amount of resistance 53 that is put I in the circuit below the line 58. The strobotron has a critical voltage and does not fire until the difference in potential between the cathode and control grid, i. e., between lines 58 and 41, equals or exceeds that value. That value is normally between 80 and 125 volts for the tube described. The resistance 53 will be set to establish a potential difierence approximately equal to the firing or triggering voltage of the tube at the desired cut-out speed.

The direct current flowing from the terminals of rectifier 4'8 divides, some serving to charge condenser 50 and some leaking off through the potentiometer 53 to ground. This current flow increases as a function of the speed of the magneto and hence, of the engine by which it is driven. When the voltage drop or potential difference between lines 58 and 41 and hence, between the cathode and control grid of tube 5| equals or exceeds the triggering voltage of the tube, the latter is instantly rendered conductive. The condenser then discharges across the main electrodes of tube 5|, energizing coil 30, operating the relay armature 3|, and short circuiting the current within the magneto primary in the manner heretofore described. At the same time the current within the transformer secondary iscut OE and the tube 5| is quenched.

The engine is immediately brought to a stop and cannot be restarted until the relay armature 3| has been returned, by means of reset button- 35, to its original position.

As a specific example of an operative mechanism, a device conforming to the foregoing specification was constructed and operated in which the resistance 52 was of the value of .5 megohm. The potentiometer 53 had a maximum value of 5 megohms and the resistance 54 had a value of l megohm. The condenser was of .25 mi. The transformer primary was of 1200 turns of No. 38 copper wire in which L=.75 h. and the secondary was of 10,000 turns of No. 38. The strobotron was No. 63l-Pl. The operating range of the test unit lay between 1,000 and 2,500 magneto R. P. M. The inductance of transformer coil 4| was between 3 and 5 mh. and that of coil 12 was .75 h. so that it did not drain any appreciable current from the magneto during operation. The primary of the transformer was connected in parallel to the magneto primary, at the high tension side terminal of the magneto switch; the secondary winding had its tap grounded and both its ends connected to a condenser across its output terminals. The strobotron was connected over a relay coil in parallel with the condenser terminals while the tube control grid was connected to the potentiometer.

, The average starting voltage of a strobotron tube 631-P1 is to volts, measured between t the regulating grid and the cathode. The potentiometer should be capable of adjustment to insure a minimum of about volts across the control elements of the tube at the desired cutout speed to thereby insure the establishment of a sufiicient potential to fire the'tube and operate the governor.

An advantage of this invention is in the production of a self-contained governor unit that is adapted to be connected by a singe wire to the switch box of an engine and that requires no other electrical installation.

Another advantage of the invention is in a governor that operates from the primary magneto circuit without weakening its efiiciency.

Another advantage of the invention is a governor unit which is capable of being adjusted to different cut-01f speeds by the simple control of a variable resistance.

Although only a single embodiment of the invention has been illustrated and described in the accompanying drawing and specification, it is to be expressly understood that the invention is not limited to said embodiment. Various changes may be made therein, particularly in the design and arrangement of the parts illustrated and in the materials used, without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art. For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1. An electric circuit having a source for generating an alternating current of variable intensity, current operable means to ground said circuit, means to generate current of intensity proportional to that of said A. C. circuit, and means responsive to the intensity of said genera-ted current to pass a current through said grounding means whereby to ground said circuit when the intensity of said generated current attains a selected level.

2. A magneto circuit, current operable means to ground the said circuit, means adapted to generate a current having an intensity proportional to the speed of the magneto, and means responsive to the intensity of said current to pass a current through the grounding means when the intensity thereof reaches a selected level.

3. A magneto circuit, current operable means to ground the said circuit, means adapted to generate a current having an intensity proportional to the speed of the magneto, and electronic valve 'means to pass the said current through the grounding means when a selected magneto speed is reached.

4. A magneto circuit, a relay adapted by operation to ground the circuit, and means to operate the relay at a selected magneto speed comrising a direct current circuit, means to proportion the said current to the speed of the magneto, and means to operate the relay when the voltage-drop across selected points in said 3). C. circuit attains a selected intensity comprising an electronic valve operable in response to said voltage-drop.

5. A magneto circuit, a relay adapted upon operation to ground the said circuit, a transformer operable by current from the magneto, and a rectifier, a condenser and an electronic tube in circuit with said transformer and said relay, the activating circuit of the tube being bypassed through a variable resistance around the relay, and the firing path of the tube being in the relay circuit.

6. A magneto primary circuit, a relay adapted upon operation to ground the said primary circuit, a transformer operable by current from the magneto, and a rectifier, a condenser, a series of resistances and a normally non-conductive electronic tube in the relay circuit, the grid of the tube by-passing the relay through a part of the resistances, and the main path of the tube serving to discharge the condenser through the relay.

7. In electrical apparatus of the class described, a main circuit comprising a source of electrical energy for generating a, variable current in the circuit, means including an inductance for grounding said circuit, and a control circuit inductively coupled with said main circuit and comprising rectifier means for converting alterhating current into direct current, a condenser and a resistance connected in parallel to the output terminals of said rectifier means, and a normally non-conductive electronic valve and said inductance connected in series across said resistance, said valve beingrendered conductive when the voltage-drop across a selected part of said resistance reaches the on-set voltage of said valve thereby permitting said condenser to discharge through said inductance and valve to sheet operation of said grounding means.

3. Electrical apparatus as defined in claim 7 and comprising releasable means for holding the grounding means in operative position for grounding said main circuit.

9. In electrical apparatus of the class described, a main circuit comprising a source of electrical energy for generating a variable current, a control circuit energizable by said main circuit includin a normally non-conductive electtronic valve, a condenser, means connecting the valve in the discharge path of the condenser, and means responsive to the discharge of said condenser through said valve for rendering said main circuit impotent.

10. In electrical apparatus of the class described, a main circuit comprising a source of electrical energy for generating a variable current, a control circuit energizable by said main circuit including a condenser and an energy consuming load, means operable in accordance with the voltage-drop across at least a portion of said load for controlling the discharge of said condenser, and means responsive to said discharge for rendering said maincircuit impotent.

11. In electrical apparatus of the class described, a main circuit comprising a source of electrical energy for generating a variable current, a control circuit energizable by said main circuit including a condenser, means for controlling the discharge of said condenser including an energy consuming load in said control circuit and an electronic valve operable in response to the voltage-drop across a selected portion of said load, and means responsive to the discharge oisaid condenser for rendering said main circuit impotent.

12. In electrical apparatus of the class described, a main circuit comprising a source of electrical energy for generating a variable current, a control circuit energizable by said main circuit and including a normally non-conductive electronic valve and a condenser, and means operable by the discharging of said condenser through the valve in said control circuit to ground said main circuit when the current therein attains a predetermined value.

13. In electrical apparatus of the class described, a transformer including primary and secondary windings, a source of electrical energy for generating a variable current in said primary, and a circuit including said secondary, said circuit comprising a capacity, an energy consuming load, and means responsive to the voltage-drop across a selected part of said load to control the discharging of said capacity.

M. In electrical apparatus of the class described, a transformer including primary and secondary windings, a source of electrical energy for generating a variable current in said primary, and a circuit including said secondary, said 011'- cuit comprising a capacity, an energy consuming load, and means including an electronic valve having its control element connected to said load for controlling the discharging of said capacity.

15. In electrical apparatus of the class described, a transformer including primary and secondary windings, a source of electrical energy for generating a variable current in said primary, a circuit including said secondary, said circuit comprising a capacity, an energy consuming load, and means responsive to the voltage-drop across a selected part of said load to control the discharging of said capacity, and means rendered operable by the discharge of said capacity to short-circuit said primary.

16. In electrical apparatus of the class described, a. transformer including primary and secondarywindings, a source of electrical energy for generating a variable current in said primary, a circuit including said secondary, said circuit comprising a capacity, an energy consuming load, and means including an electronic valve having its control element connected to said load for controlling the discharging of said capacity. and means including an inductance rendered operable by the discharging of said capacity to shortcircuit said primary winding.

TULLIO TOGNOLA.

REFERENKIES @I'lllED v The following references are of record in file of this patent:

Number Number UNITED STATES PA Name te Field Feb. 2%, i891 Compton July 4, 1916 Curtis Oct. 16, 1928 Bird Nov. 10, 1936 Miller Jan. 19, 1937 Jones Feb. 8, i938 Knowlton May '2, 1%9 Sturm et al Dec. 2%, 19% Scott June 16, 19%,); Reagan Feb. 29, 1221 Baumann Aug. 1 1, i945 FOREIGN PATENTS Country Date Switzerland Oct. 16, 1933

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