US2052128A - Starting device for internal combustion engines - Google Patents

Description

A. CALLSEN Aug. 25, 1936.

STARTING DEVICE FOR INTERNAL COMBUSTION :ENGINES Original Filed April 18, 1932 2 Sheets-Sheet 1 A. CALLSEN Aug. 25, 1936.

STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Original Filed April .18, 1932 2 Shets-Sheet 2 I Ill/Ill Patented Aug. 25, 1936 PATENT orr ce- STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Albert Callsen, Stuttgart, Germany, assignor to Robert Bosch Aktiengesellschaft, Stuttgart,

Germany Original application April 18, 1932, Serial No. 606,006. Divided and this application March 26, 1935, Serial No. 13,169. In Germany April 12 Claims. (Cl. 290-38) The present invention relates to a starting device for internal combustion engines, in which an electric motor is employed and preferably also an inertia mass which is brought to a high speed of rotation by means of the electric motor, and

then coupled to the internal combustion engine to be started, and in which a friction clutch is introduced into the driving connection to the pinion engaging in the rim of the flywheel of the engine.

This application is a division of my applica tion Ser. No. 606,006, filed April 18, 1932.

In a known arrangement the pinion is permanently connected with the inertia mass so as to transmit power through a. spring-loaded plateclutch.

This construction has the disadvantage that each time on the engagement of the pinion in the toothed rim of the flywheel oi the motor the pinion as well as the toothed-rim of the flywheel are strongly worn and even are often damaged. It is also already known in electric starters which have no separate inertia mass to make the plate-clutch inserted between the pinion and the armature of the starting motor capable of transmitting power by a pressure member which can screw axially on the driving shaft. In this case the clutch only establishes the power connection when the pinion on coming into engagement, is prevented from freely rotating. In order however, that the pinion may fully engage, it must become engaged by an auxiliary force before the transmission of the main torque, since an immediate engagement under full load would not be possible because the flank pressure of the teeth is so great from the first moment of the engagement that the axial attractive force of the armature does not suflice to entirely push in the pinion. This second construction is thus not at all possible for flywheel starters-because in these the full torque is present immediately upon engagement. V

According to the present invention the drawback of the first-mentioned construction is removed, whilst the starting device of the secondnamed construction is also made applicable to flywheel starters in that the power connection between the pinion and the inertia mass, which is efiected by a plate-clutch operated by an axially screwing pressure member, is capable of being initiated at will.

An example of construction of a starter according to the invention is shown in the accom-.

pcnying' drawings, in which:-

1 is a semi-diagrammatic sectional view of a starter having an axially adjustable armature, in the position of rest,

Figure 2 is a plan of connections of the starting device,

Figure 3 shows the starter in engagement, but with the plate-clutch out of engagement, and

Figure 4 shows the starter in the working position.

In Figures 1, 3 and i, l is the armature of an electric starting motor which in known manner can be axially displacedvby the magnetic force of the field winding. n the armature shaft 2 is keyed a flywheel 3 and a pinion 4 is revolubly mounted on the shaft 2. The pinion 4 has a shank 5 which has an external thread 6 of quick pitch. A nut i can move on the shank by means of the thread 6. The torque of the armature l is transmitted to the pinion 4 through a plateclutch 6. The plates 9 of the clutch engage by means of projections ID in recesses H in the flange it of the flywheel 3, whilst the plates i3 engage by projections M in grooves l5 in the nut i. A. spring ii is tensioned between the nut l and a stop i6 on the shank 5 of the pinion, and the spring tends to push the nut '1 against the plates.

In an opening of the casing l8 a lever 19 is pivotally mounted above the plate-clutch 8. One end of the lever projects into the casing, and

strikes against a flange 2! on the nut i when the lever is rocked, and displaces this latter on the shank 5.- The lever ,is pulled back by a spring 24 into its position of rest. Further, a switch 22 is so arranged on the casing l8, that the switch arm is brought into the switched on position by a finger 23 on the lever l9 when the lever is rocked. The switch arm carries a contact 26, opposite to which a contact 21 is fastened in an insulated manner on the casing. The switch arm 25 is held in its on position by a holding coil 28 and is raised by a spring 29 as soon as the holding coil is deprived of current.

In the diagram of connections, Fig. 2, 30 is a 0 battery, one pole of which is connected to earth and the other pole to a brush 34 of the starting armature I. To the other brush 35 is connected one end of an auxiliary field winding 3! and one end of the holding coil 28 of the switch 22 as well as one end of the main field winding 33. The two other ends of the windings 28 and 3| are connected to one pole of the switch 32, the other pole of which is earthed. The second end of the winding 33 is connected to the insulated contact 21 which lies-opposite the contact 26 on the switch arm 26 connected to earth.

The mode of operation of the starting device is as follows:.- A

In order to start the internal combustion englue, the switch 32 is closed, thus closing the circuit through the auxiliary field winding 35. It is plain from Fig. 2 that the holding coil 28 in parallel with the auxiliary field winding is also excited by the closing of the switch 32, but as that coil is unable to close the switch 22 which controls the circuit through the main field winding of the ,motor, the closing of the switch 32 brings the auxiliary field Winding only into operation. The result'of this is, first, that the, armature l is axially displaced in known manner by themagnetic force of the auxiliary field winding 3! and set in .slow, rotation. At this time the clutch is sufiiciently engaged, that is, there is a sufiicient frictional clutch connection between the armature i and the pinion #3, by way of the pressure of the nut i against the clutch plates under the tension of thespring H and the engagement between the nut and the shank of the pinion, to cause the pinion topartake of the slow 'rotation of the armature and to be carried along with it until the pinion engages in the toothed rim 36 of the engine fiy'wheel.

As soon as the pinion is in engagement and is prevented by the rim of the flywheel 36 from further rotation, the nut l, which is sufiiciently engaged with the clutch plates by the pressure of spring I! to continue in rotation, first screws itself along the shank of the pinion further toward the plates in consequence of the threaded connection between the nut and the shank of the 'pinion and their relative rotary movement and thereby puts the pinion. I

The torque of the starting motor is however too small in this first, switch position to turn over the engine and the motor stops. The lever i9 is now moved into the position shown in Fig. 3. On rocking the lever, the nut 'i is moved away from the clutch plates towards the stop it against the tension of spring H and thereby the clutch released. At the same time the switch arm 25 is pressed by the finger 23 against the contact 21. The working current circuit is thus now out in, since the main field winding is' also earthed through the switch 22. The starting motor now runs idly with the inertia mass at a high speed and a series wound motor attains of course a very high speed. Inorder to re-engage the clutch 8, the lever is is moved back into its starting posiclutch into operation on the tion. The spring H again pushes the nut i towards the plates and thus initiates the driving connection between the armature i and flywheel 3 on the one hand and the hand.

The nut i now presses the plates together with a force which corresponds to the torque required on the pinion or, what amounts to the same pinion ti on the other v thing, in accordance with the load imposed on the inertia mass in turning over the engine. The working current circuit of the starting'motor remains closed by the holding coil 28 so that the starting motor can further assist the action of the flywheel 3. When the speed of the starter on starting the engine is exceeded by the speed of the. engine, the pinion comes out of engagement in known manner.

In the above-described mode of operating the starting device. it is to be noted that the succession of operations are the advancement of the pinion into engagement with the toothed rim of the flywheel by displacement of the armatureupon closure of the switch a: of the auxiliary winding, then disconnecting the pinion from the inertia mass and setting the latter into full speed rotation by movement of the lever I 9 to throw out the the connected inertia mass are in slow rotation due to the initial excitation oi the auxiliary field winding only.

However the pinion can also be put in engagement by the lever i9 instead of with the aid of the displaceable armature, the nut l and the shank of the pinion being so formed that the nut can again. screw itself back towards the clutch to a distance corresponding to the displacement for engaging the pinion, in order to make the clutch operative.

This makes it possible to effect the engagement of the pinion with the toothed rim of the engine fiywheel after the inertia mass has been set in and while it is still in full speed rotation and without damage to either the pinion or the engine flywheel, for at the moment when the pinion is moved by the lever toward the engaging position of the pinion with the engine flywheel the clutch becomes disengaged and the connection between the pinion and the rapidly rotating inertia mass is thereby broken and remains so as long as the lever is pressed against the nut. After the pinion is thus engaged with the toothed rim of the engine flywheel, the lever i9 is moved back to its neutral position and this movement of the lever, of course, relieves thenut d from the pressure of the lever against it, whereupon the spring it again pushes the nut towards the'clutch plates and thus initiates the driving connection between the rapidly rotating inertia mass and the pinion to turn over the engine through the established engagement of the pinion with the toothed rim of the engine flywheel.

In carrying out the last-described method of starting by the device with the electric motor and circuit arrangements shown in the drawings; the first operationstep of setting the inertia mass in full speed rotation before the pinion is engaged with the engine flywheel may be performed by leaving the switch 32 for the auxiliary field winding of the motor open so as to avoid that displacement of the armature which would ad- Vance the pinion into engagement with the engine flywheel before the inertia mass has been spceded up, and manually closing the switch 22 for the main field winding as may be required to set the armature and the connected inertia mass into full speed rotation. I

A further advantage of the starting device ac.-

cording to the invention consists in that the use tor, a pinion freely mounted on the shaft of the armature, said pinionhaving a shank, a nut mounted to rotate on the shank of said pinion, a

plate-clutch between said pinion and said inertia mass controlled by said nut and means to displace said nnt. relatively to said pinion to operate said clutch at will.

engines comprising an electric motor having a rotor and shafttherefor, an inertia. mass secured to the rotor of said motor, a pinion freely mounted on the shaft of the rotor, a sleeve secured to said pinion, an external thread'on said sleeve, a nut engaging said external thread, a plateclutch connecting said pinion and said inertia. mass and controlled by said nut, a spring urging said nut to engage said plate-clutch, and a lever operable at will to displace said nut to disengage said clutch.

3. A starting device for internal combustion engines comprising an electric motor having a rotor and a shaft therefor extending beyond said rotor, an inertia mass secured to the rotor of said motor, a pinion freely mounted on the shaft of the rotor, a sleeve secured to said pinion, an

external thread on said sleeve, a nut engaging said external thred, a plate-clutch connecting said pinion and said inertiamass and controlled by said nut, a spring urging said nut to engage said plate clutch, a lever operable at will to displace said nut to disengage said clutch and means to close-the power circuit of said motor upon operation of said'lever.

4. A starting device for internal combustion engines comprising an electric motor having a rotor and a shaft therefor extending beyond said rotor, a power circuit for said motor, an inertia mass secured to the rotor of said motor, a pinion freely mounted on the shaft of the rotor, a sleeve secured to said pinion, an external thread on said sleeve, ,a nut engaging said external thread,

a plate-clutch connecting said pinion and said inertia mass and controlled by said nut, a spring -urging said nut toengage said plate-clutch, a

lever operable at will to displace said nut to disengage said clutch, a switch to close the power circuit of said motor upon operation of said lever and means to hold the said switch in the closed position.

5. A starter for internal combustion engines comprising an electric motor having an axially displaceable rotor and shaft, a main power circuit, an auxiliary field circuit adapted to axially displace the rotor of said motor and connected in parallel with the main power circuit, a switch in the main power circuit, a holding coil for said switch, an inertia mass secured to the rotor of said motor, a pinion freely mounted on the shaft of said rotor, a, nut mounted on said pinion, a

plate-clutch operated by said nut and connecting said pinion with said inertia mass, and a lever operable at will to disengage said clutch and to close said switch upon operation.

6. A starting device for an internal combustion engine comprising the combination, with an internal combustion engine having a gear adapted to be driven to turn over said engine, oi an electric motor having an axially movable armature, a shaft axially movable with said armature, an

auxiliary field winding adapted upon excitationto impart axial movement to said armature and to rotate the same at relatively low speed, a pin ion rotatably mounted on said shaft out of errgagement with said engine gear in one position of said armature and shaft but movable upon said axial movement of said armature and shaft to engagement with said engine gear, a main field winding for said motor adapted on excitation to impart high speed rotation to said armature, an inertia mass mounted for rotation with said armature, a clutch-controlled driving connection between said inertia member and said pinion, a

a displaceable rotary driving member out ofengagement with the engine in the non-starting position, means to shift said driving member into said engagement to start the engine, a friction plate clutch between said driving member and said inertia mass, means comprising a control member automatically movable in dependency on the position of said driving member to control said clutch and manually operable means to displace said control member to operate said clutch at will.

8. A starting device for an internal combustion engine comprising an electric motor, a displaceable driving member out of engagement with the engine in the non-starting position and bodily movable into said engagement to start the engine, means for driving said member from said motor including a multiple-part clutch automatically operating to establish a connection between said driving member and said motor and disengageable to break said connection, a single manually operable member and means actuated thereby to shift said driving member from its said non-starting position into engagement with the engine, to temporarily disengage said clutch upon said engagement of said driving member with the engine and to set said motor into full speed operation while said clutch is thus disengaged. 9. A starting device for an internal combustion engine comprising an electric motor, a .displaceabie pinion out of engagement with the engine in the non-starting position and bodily movable into said engagement to start the engine, means for driving said pinion from said motor including a multiple-part clutch automatically operating to establish a driving connection between said pinion and said motor and disengageable to break said connection, and means tion engine comprising an electric motor, a rotatable member adapted to be rotatably driven by said motor, said rotatable member being normally out of engagement but movable axially into engagement with a part of the engine to turn over the latter, a clutch normally establishing a driving connection between said rotatable mem loci and said motor and operable at will to break and remake the connection, means to energize said motor for low speed operation thereoi and to energize said motor for high speed opera tion thereof, means automatically operating to move said member axially into engagement with said engine part when said member is connected through said clutch with said motor and the letter is set into low speed rotation; and means operable upon said clutch at will when said member is connected to said engine part to break the connection between said member and said motor while retaining said member in connecbetween said member and said motor whereby the torque of the high speed drive -of said motor may be transmitted through said member to said engine part to turn over the latter.

11. A starting, device for an internal combus= tion engine comprising an electric motor operable at low andhigh speeds, a displaceable pinion out of engagement with the engine in the nonstarting position and bodily movable into said engagement to start the engine, means for driving said pinion from said motor comprising a multiple-part friction clutch automatically operating to establish a driving connection between said pinion and said motor and disengageable to break said connection, means including said motor and said pinion-driving means automatically operating to advance said pinion into engagement with the engine upon actuation of said motor at low speed, a member manually operable to temporarily disengage said clutch after said advancement of said pinion into engagement with the engine, and means operated by said member in disengaging said clutch to establish an energizing circuit for the full speed operation of said motor.

12. A starting device for an internal combustion engine comprising the combination, with an internal combustion engine having a gear adapted to be driven to turn over said engine, of an electric motor operable at low and highspeeds and having an axially movable armature, means 5 for energizing said motor for low speed rotation and axial movement of said armature during said low speed rotation, a rotatable pinion out of engagement with said engine gear when said armature is in its initial position but.shiitable i axially into engagement with said engine gear upon said axial movement of said armature. a clutch-controlled driving connection between said motor and said pinion automatically operating upon said low speed rotation and axial move- 15 ment of said armature to rotate said pinion idly at the low rotation speed of said motor and advance said pinion into engagement with said engine gear and therafter upon high speed rotation of said motor to impart the torque of said 20 high speed rotation through said pinion to said engine to turnover the latter, and means comprising a lever operable at will, upon said advancement of said pinion into engagement with said engine gear, in one direction of movement 25 to disengage said clutch and energize said motor into high speed rotation and in an opposite direction of movement to re-engage said clutch.

ALBERT CALLSEN.

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