US3124694A

US3124694A - Combustion engines

Info

Publication number: US3124694A
Authority: US
Publication date: 1964-03-10
Anticipated expiration: 1981-03-10

Description

March 10, 1964 A. H. SEILLY ELECTRIC STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed April 13, 1962 2 Sheets-Sheet 1 .March 10, 1964 E|L| Y I 3,124,694

A. H. S ELECTRIC STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed'April 13, 1962 2 Sheets-Sheet 2 2 25 28 Fig.2 A

United States Patent 3,124,694 ELECTRIC STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES Alec Harry Seilly, Middlesex, England, assignor to C.A.V. Limited, London, England Filed Apr. 13, 1962, Ser. No. 188,617 Claims priority, application Great Britain Apr. 24, 1961 1 Claim. (Cl. 290-38) This invention relates to electric starting mechanism for internal combustion engines and of the kind comprising in combination an electric motor, an axially movable sleeve on which is formed or secured a pinion adapted for engagement with a toothed wheel on the engine, said sleeve being mounted on and having quick-pitch screw-thread or equivalent connection with the motor armature shaft or a shaft connected thereto, a solenoid core mounted on the sleeve, the core and sleeve having interacting parts whereby axial movement of the core in one direction will impart a corresponding initial axial movement to the sleeve, to eifect initial engagement of the pinion with the engine wheel, a solenoid winding surrounding one end of the core, a resiliently supported member carrying contacts of a pair of switches respectively, and a catch co-operating with the member, the arrangement being such that in use, when the initial movement has been imparted to the sleeve by energisation of the solenoid, the first switch is closed by tilting the member, to cause rotation of the motor at relatively slow speed, and thereby cause the screw-thread or equivalent connection to cause the sleeve to partake of further axial movement to engage the pinion fully with the toothed wheel of the engine, this further movement of the sleeve causing the latter to release the catch and allow the second switch to close thereby applying full power to the motor.

The object of the present invention is to provide an improved construction of such mechanism.

According to the invention in electric starting mechanism of the kind specified the catch is loaded in a direction to engage the member by means of a spring one end of which acts upon the catch, whilst the other end acts upon the core, so that when the initial movement has been imparted to the core, the force of the spring acting to hold the catch in engagement with the member is reduced.

In the accompanying drawings:

FIGURES -1, 2, 3 are part sectional fragmentary side views of one example of the invention and in successive stages of operation.

Referring to the drawings there is provided a rotor armature 1 having an extended axial shaft -2. Slidably mounted on the shaft and rotatable therewith is a nonmagnetic sleeve 3 having secured thereto a pinion 4. The pinion and shaft are interconnected by a quick pitch screw-thread 8 whereby when the shaft is rotated in one direction relative to the pinion the latter will be moved axially away from the armature 1 into mesh with teeth formed on the periphery of a flywheel 5' of the associated engine against the action of a compression spring 6 located between the pinion and an abutment '7 on the end of the shaft. The sleeve 3 is surrounded by an axially slidable hollow cylindrical iron core 9 of a solenoid having a winding 10 which is of annular form and is mounted on the rotor casing 11. The core 9 is provided with a shoulder 10 which abuts against an annular step 10a on the sleeve so as to permit limited relative axial movement of the core and sleeve.

Also mounted on the sleeve 3 is an axially slidable collar 12 which is loaded by a compression spring 13 and serves to move a plurality of catch balls 1-4 into engagement with an annular row of recesses 15 in the shaft 2 for securing the sleeve to the shaft when the pinion '4 is moved into engagement with the teeth on the flywheel 5 of the engine so preventing inadvertent return of the sleeve to its rest position before the engine has been fully started.

Adjacent the end of the solenoid nearest the armature is an annular electrically insulating disc 16 which carries a pair of

fixed contacts

17, 18 forming part of two electric switches respectively. The moving contacts 19*, 20 of the switches are carried by a substantially rectangular tiltable member =21 located against a shoulder 22 on the core 9 by a compression spring 23 of helically coiled conical form. A further compression spring 9b is interposed between the d-isc 16 and the shoulder 22 on the core 9 to urge the core towards the armature. At one angular position on the member 21 there is provided a tongue piece 24 which is inclined relative to the plane of the member in a direction away from the rotor. Extending from the disc 16 towards the armature at sub stantially the same angular position as the tongue piece 24 is a support 25 having pivotally mounted thereon a catch 26 in the form of a bell crank lever. On one arm of the catch is a projection 27 to engage over the tongue piece in the manner of a hook.

The catch is loaded into engagement with the tongue piece by means of a coiled torsion spring 29 of the housepiece by means of a coiled torsion spring 29 of the mousetrap type surrounding the pivot 2S, one end of the spring bearing on the other arm of the catch and the other end of the spring bearing on the end of the core. Mounted on the end of the sleeve nearest the armature is an annular catch release plate 30 provided to co-operate with the other arm of the catch when the sleeve moves away from the armature as during the starting sequence.

In use when the solenoid it) is energised, by closure of a switch (not shown), the core 9 and all the parts mounted thereon move axially away from the armature. When the shoulder 9a on the core abuts against the step 3a on the sleeve the sleeve is urged by the core axially away from the armature against the action of the spring 6 and eifects the initial engagement of the pinion 2 with the teeth of the flywheel 5. At the same time and as shown in FIGURE 2 the tongue 24 on the member 21 abuts against the projection 27 on the catch and the member is tilted against the action of the spring 23, allowing the

contacts

17 and 19 to close and permitting the starter rotor to be energised through a resistance (not shown). As the armature 1 is rotated the pinion is moved into full engagement with the teeth on the flywheel as shown in FIGURE 3, due to the action of the quick pitch screwthread 3 and as the armature is rotating slowly, because of the resistance in the circuit, the engagement will be smooth. As soon as the pinion is in full engagement with the flywheel the catch balls 1'4 will move into the recesses 15 to retain the sleeve relative to the shaft. Immediately prior to full engagement the catch release plate 30 moves the catch 26 angularly to release the tongue 24 and allow the

contacts

18, 20 to close. Closure of the

contacts

18, 20 short circuits the resistance and the armature rotates at full speed to rotate the flywheel.

Since one end of the spring 29 is located against the core the spring force on the catch is reduced as the core moves axially. Consequently when the catch release plate 39, which is rotating, contacts the relatively nonrotating catch, wear on the parts will be minimised. Moreover, minimum force is required to release the catch.

After the engine has been set in rotation the switch in the solenoid circuit is re-opened and the various parts are restored to their initial position by the screw connection between the shaft and the sleeve, the contacts 3 being separated by the action of the spring 911 on the shoulder 22 on the core 9.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

An electric starting motor for an internal combustion engine having in combination, an armature shaft, an axially slidable sleeve mounted on said shaft and pro- 'vided with a pinion for engagement with a toothed wheel of the engine, means interconnecting the sleeve and the shaft so that relative rotation thereof will impart axial movement to the sleeve, a hollow cylindrical solenoid core-surrounding said sleeve, a stationary annular electromagnet Winding surrounding one end of said core and serving, when energised, to impart axial movement to said sleeve through said core, a disc surrounding said core, mean-s engaging said disc and the core for permitting til-ting of the disc relative to the core, a first motor control switch movable to a closed position by said disc [for permitting an initial restricted supply. of current to the motor, a second motor controlled switch movable to a closed position by said disc for permitting a full supply of current to the motor, a pivotal catch member for preventing movement of said disc to close said second switch, a spring for urging saidcatch member into engagement with said disc, said spring having one limb'bearing against the catch member and its other limb bearing against said core so that when the core moves under the influence of the solenoid the .force required to move the catch will be reduced, and a tripping member mounted on the sleeve for moving the catch member to a position to release the disc.

References Cited in the file of this patent UNITED STATES PATENTS 2,727,158 Seilly Dec. 13, 1955 FOREIGN PATENTS 1,217,454 France Dec. 7, 1959