US1996521A - Automatic starting mechanism - Google Patents

Description

April 2, 1935.

I AUTOMATIC STARTING MECHANISM Filed May 28, 1952 I Y m Vmvrok flow/z LU. M A TTORNEY P. MAURER 1,996,521 I Patented Apr. 2, 1935 UNETED STATES PATENT OFFIE Paul Maurer, Clifton, N. J., assignor to Eclipse Machine Company, Elmira, N. Y., a corporation of New York Application May 28, 1932', Serial No. 614,221

Claims.

This invention relates to automatic starting mechanism for internal combustion engines and more particularly to controlling devices for venting closure of a starting switch while the engine is running and causing closure thereof in case of engine stall.

In automatic starting mechanism of the type employing a control relay energized from an engine driven generator'to hold the starting switch open during self-operation of the engine, it is of course desirable that the action of the relay be uniform and reliable. That is, the relay should hold the starting circuit open during the lowest idling speeds of the engine, but should release unfailingly when the engine stops.

It has been found that in order for the relay to hold open under the influence of the feeble current supplied by the generator at idling speeds, or supplied by thestarting motor when the armature thereof is spinning by momentum in its residual field, the magnetic circuit of the relay should be substantially closed. On the other hand, however, when the relay armature is allowed to contact its pole piece, a residual flux is maintained in the magnetic circuit thus closed, which may in some cases prevent the release of the relay when the exciting current drops to zero.

Moreover, when the armature of the relay is allowed to contact the pole piece, the releasing action of the relay is affected by the area of the surfaces in contact, and variations of this area due to inaccuracies in formation of the parts or wear in service may materially alter the characteristics of the relay.

It is an object :of the present invention to provide a novelcontrol relay for automatic starting mechanism'which is uniform and reliable in operation irrespective of reasonable tolerances in manufacture and wear in service.

It is another object to providesuch a device embodying means for accurately and permanently whereby opening of such switch causes the to be biased toward idle position.

Further objects and advantages will be apparent to those skilled in this art from the following description taken in connection with the accompanying drawing in which:

Fig. i is a semi-diagrammatic showing of a preferred embodiment of the invention;

Fig. 2 is an enlarged detail partly in longitudinal section showing one method of spacing the relay armature from its pole piece; and

Fig. 3 is a view similar to Fig. 2 showing a slightly different arrangement with respect to the spacing means.

Referring to Fig. l of the drawing, there is illustrated a battery I grounded at 2 and connected by a lead 3 to a magnetic starting switch indicated generally at 4. The starting switch is connected through a single turn coil 5 and lead 6 to a starting motor SM which is grounded at T to complete the starting circuit.

A solenoid 8 is provided for closing the starting switch 4, and is energized from the battery I by means of a control circuit including battery lead 3, ignition switch 9, lead ll, lead I2, fixed contact 13 and movable contact I4 which is mounted on a spring strip 15 grounded at Hi to complete the control circuit.

Contact I 4 is normally in engagement with contact l3 but is arranged to be. moved onto! engagement therewith by means of a pivoted lever (1 which is moved bya magnetic plunger isso as to engage a weight member IS on the end of the spring'strip l5. and bend said strip backward to break contacts l4, I5. Plunger i8 is normally biased toward its upper position as -il-- lustrated by yielding means such as a spring 2| and is retracted into position to open contacts [3, I4 when the engine starts by a solenoid 22 having a fixed pole piece 20. Solenoid 22 is connected at one end by a lead 23 to the starting morelay adjusting the sensitivity and electro-magnetic Side Of t Starting Switch 4 and is grounded balance of the relay.

It is a further object to provide such a device in which the adjusting means may readily be set to compensate for variations in the characteristics of the individual automatic starting device.

It is another object to provide such a device embodying an arrangement whereby magnetic sticking of the relay is eiiectively prevented.

It is another object to pr'ovide such a devicein which the electro-piagnetic balance of the relay is under the control. of a manually operable member such as the ignition switch of the engine at its opposite end as indicated at 24. Coil 22 also serves to maintain the plunger IS in its retracted or switch-open position as defined by the pole piece 20, by virtue of current generated by the starting motor when spinning by momentum whereby reclosure of the contacts is prevented until the starting motor comes substantially to rest. I

Means are provided for maintaining the plunger l8 retracted duringthe self-operationoi' the engine in the form of a solenoid 25 connected at one end by a lead 26 to an engine driven generator G, and also grounded atits opposite end at 24.

In commercial devices of this character, some difliculty has been encountered in securing entirely uniform action of the relay under thecontrol of the feeble currents generated by the starting motor during spinning and by" the generator during slow idling of the engine. In other words, relays which are arranged to unfailingly be held downby these feeble currents are usually constructed with substantially closed magnetic circuits and therefore occassionally fail to release when the currents\cease altogether, by reason of the residual flux in the magnetic circuit of the relay; whereas if the springs 2| are made sumciently still tounfailingly release the relay, the relay may fail to be held down during motor spin or during very slow idling of the engine.

' ture I8 is prevented from making direct contact with the pole piece 211, the effect of such inaccuracies or wear is' reduced, and'the action of the relay is uniform and dependable. Obviously, however, if there be a non-magnetic gap between the armature and pole piece, more ampere turns are required to secure the flux necessary to hold the armature I8 in its retracted position.

According to the present invention, the prob lems here presented are solved by interposing a on-magnetic spacing means in the form of a disc 21 between'the armature l8 and the poles piece 20, and supplying a'source of additional ampere turns in the form of a third solenoid 28,

"solenoid being grounded auxiliary circuit.

the magneto-motive force of which is adjustable in order to compensate for the additional reluctance in the magnetic circuit of the relay caused by the spacing means 21. As here shown this is accomplished by connecting the solenoid 28 to the battery I through the ignition switch 9, lead 29, variable resistance 3| and lead 32, the at 24 to complete the It will be understood. the he thickness of the spacing means 21 has b en exaggerated in the drawing inasmuch as the actual thickness thereof would be a matter of a few thousandths of an inch only. This spacing means may be formed in any suitable way, as for instance by plating the end of the armature or of the pole-piece or both, or as illustrated-in Figs. 2 and 3 it may be formed as a separate disc inserted loosely in the core 33 of the relay. I Q

As illustrated in Fig. 2, the core is provided with a shoulder 34 adapted to limit the upward movement of the spacing disc 21, and the arnia: ture l8 is slightly reduced in diameter from the diameter. of the pole piece 20. As shown in Fig. 3, a shoulder 35 is rolled in the core 33 for the same'purpose and the armature I8'is provided with a slightly reduced extension for engaging the spacing member 21. r

In adjusting the device for-use, suitable values are selected for limiting values of current traversing the holding coils 22 and 25 below which limits the relay must release and above which limits the relayjmust be retained in running position. The coils are thereupon energized'selectively by currents of the limiting values and the resistance 3l1s adjusted to vary the flux through the auxiliary coil 28 until release of the relay.

ed out be maintained within close limits through long periods of service. If, however, the magnetic balance should be disturbed in any way, the resistance 3| may readily be adjusted to once more secure the desired balance.

It will be understood further that it may be desirable to vary the characteristics of the relay in accordance with the electrical characteristics of various installations. That is, the electrical characteristics of the starting motor and of the generator may vary considerably, and the coil. 28 with the variable resistance 3| offers a convenient and positive method of obtaining the optimum by is of course much too small to have a perceptible effect on the armature l8. When the starting switch 4 is closed by solenoid 8, the starting circuit is closed and the starting motoris energized to crank the engine. At the same time, the motor shunt coil 22 is energized through the lead 23, but the flux produced thereby is opposed bythe single turn coil 5 which retains the armature l8 in its upper position as long as the coil 5 is traversed by the heavy cranking current.

When the engine starts, the reduction in current flow through the series coil 5 and the concomitant rise in voltage across the shunt coil 22 enables the shunt coil to overcome the series coil and attract the armature is against the pole piece 20. Contacts l3, l4 are opened thereby, deenergizing solenoid 8 and causing the starting switch 4 to open. Shunt coil 22 is thereby cut off from the battery I but is still energized to a small extent by current generated by the spinning of the armature of the starting motor in its residual field. This flux throughcoil 22, assisted by the flux in the auxiliary coil 28 is sufficient to retain the armature l8 in its attracted position,

until the starting motor comes substantially to rest. 'i

When the enginestarts the generator G 1 driven thereby picks up and energizes the generator coil 25 to retain the armature l8 in its attracted position as long as the engine is self-operative. It will be understood that during slow idling the flux from the generator coil 25 may fall to a very low value, but as above pointed out, the auxiliary coil 28 is so adjusted as to assist coil 25 sufli-' ciently to retain the armature It as long as the engine is self-operative.

It has been found that the' sensitivity of the nently than in those cases where the armature is allowed to make direct contact with its pole piece.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in thedesign and arrangements of the parts without departing from the spirit of the'invention as defined in the claims appended hereto.

What is claimed is:

1. In an automatic starting mechanism for internal combustion engines, a starting switch, a control relay therefor having an armature normally biased to idle position, magnetic means for attracting and holding said armature while the engine is self-operative, and adjustable electromagnetic means under the control of the operator for supplementing the residual magnetic holding e'iiect of the holding means and opposing the" normal biasing of the armature when in attracted position. j)

2. In an automatic starting mechanism for internal combustion engines,- a starting switch, a control relay therefor having an armature normally biased to idle position, magnetic means for attracting and holding said armature while the engine is self-operative, and adjustable electromagnetic means for supplying a constant magnetic flux to assist the residual magnetic holding eii'ect of said holding means.

. 3. In an automatic starting mechanism for internal combustion engines, a starting switch, a control relay therefor having a fixed pole piece, and an armature normally biased to idle position, magnetic means responsive to rotation of the engine for attracting and holding said armature during self-operation of the engine, means providing a non-magnetic gap between said pole piece and armature, and adjustable electromagnetic means under the controlof the operator for producing a magnetic flux in a holding direction for the armature to assist the residual magnetic holding effect of said holding means.

4.'In an automatic starting mechanism for internal combustion engines, a starting switch, a control relay therefor having an armature normally biased to idle position, magnetic means for moving said armature to running position when the engine starts and for holding the armature in running position responsive to self-operation of the engine, and electromagnetic means for supplying a constant magnetic flux supplementing the residual magnetic holding eifect of the holding means to retain the armature in running position. 5. In an automatic starting mechanism for internal combustion engines, a starting switch, a control relay therefor, electromagnetic means for retaining said relay in position'to prevent closure of the starting switch while the engine is self-operative, and adjustable electromagnetic meansunder the control of the operator for supplementing the residual magnetic holding eilect of said retaining means by a substantiallyconstant force which is insuiiicient by itself to retain said relay in switch open position.

6. In an electrical system for internal combustion engines, a starting system including a battery and a starting motor, an engine driven generator, a magnetic starting switch. a control relay for said starting switch including a movable armature and a pole piece, means for holding said armature against the pole piece during selfoperation of the engine, nonmagnetic means for spacing the armaturefrom the pole piece, and

adjustable means for setting up a substantially constant magneto-motive force through the relay supplementing the residual magnetic holding eifect of said holding means to compensate for the reluctance caused by said spacing means.

7. In an electrical system for internal combustion engines, a starting system including a battery and a starting motor, an engine driven generator, a control relay for said startingmotor including a movable. armature and a pole piece, a coil energized by rotation of the starting motor for holding the armature against the pole piece during spinning of the starting motor, a coil energized by rotation of the generator for holding the armature against the pole .piece during self-operation of the engine, a third coil energized from said battery to exert a supplemental holding effect on the armature, and means for adJusting the flux of the third coil to secure for holding the armature against the pole piece during spinning of the starting motor, a coil energized by rotation of the generator for holding the armature against the pole piece during.

and to secure uniformity of control of the relay by the first and second coils. 9. In an automatic starter control for internal combustion engines a magnetic starting switch, a control circuit therefor including an electromagnetic relay, means for biasing said relay to switch closing position, said relay including electromagnetic means responsive to a running'function of the engine for holding said relay in switch open position, additional electromagnetic means for supplementing the holding effect of said holding means inopposing said biasing means, and manually operable means for energizing and deenergizing said additional means.

10. In an automatic starter control for internal combustion engines a magneticstarting switch, a control circuit therefor including an electromagnetic relay, means for biasing said relay to switch closing position, said relay including electromagnetic means responsive to a running function of the engine for holding said relay in switch open position, additional electromagnetic means for supplementing the holding effect of said holding means whereby it is necessary for said biasing means to overcome both the residual holding effect of the holding means and the holding eflect'of the. supplemental means in order to move the relay to switch open position, and

means whereby the energization 'of said supple-,

PAUL mm.

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