US3597622A

US3597622A - Electrical switches for use in starter motors for i.c. engines

Info

Publication number: US3597622A
Application number: US28317A
Authority: US
Inventors: Ronald Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-27
Filing date: 1970-04-14
Publication date: 1971-08-03
Anticipated expiration: 1988-08-03
Also published as: SU376977A3; ES379659A1; GB1290524A; BR7019297D0; FR2043690A1; JPS4940424B1; DE2024432A1

Abstract

An electrical switch is for use in an internal combustion engine starting mechanism of the kind including a starter motor, a pinion driven by the starter motor and engageable with a toothed wheel on the engine, and a solenoid for moving the pinion into engagement with the toothed wheel, the solenoid including an armature having an inner part for moving the pinion and an outer part coupled to the inner part. A switch of this kind includes a housing and first, second and third fixed contacts secured in the housing in spaced relationship and lying in a common plane. A movable carrier is mounted for movement in a direction at right angles to the plane of the fixed contacts and a conductive bridging piece is resiliently mounted on the carrier and is urged to lie in a plane parallel with the plane of the fixed contacts. A sleeve slidably mounted in the housing is engaged at one end with the carrier and projects at its other end from the housing for engagement with the outer part of the armature. A push rod is slidable within the sleeve and projects at one end from the sleeve for engagement by the inner part of the armature, resilient means urging the sleeve and the push rod outwardly. A movable latch member is movable by the push rod and is resiliently urged to a position wherein it projects above the plane of the fixed contacts to prevent the bridging piece engaging the third fixed contact during movement of the carrier towards the fixed contacts. The arrangement is such that in use upon energization of the solenoid the outer part of the armature moves the carrier through the sleeve towards the fixed contacts, the bridging piece engaging the latch member and thus being tilted relative to the carrier during further movement of the carrier. The bridging piece in its tilted condition engages the first and second fixed contacts to complete a first circuit of the starter motor and the latch member is then moved by the push rod when the pinion of the starter motor is fully engaged with the toothed wheel of the engine to permit the bridging piece to return to its original position with respect to the carrier so as to engage the third fixed contact to complete a second circuit of the starter motor. The second circuit when completed causes energization of the starter motor at a full torque value while completion of the first circuit causes energization of the starter motor at a reduced torque value.

Description

United States Patent Ronald Wilson 13 Chelmsley Lane. Marston Green, Birmingham, England [72) inventor [2l Appl. No. 28,317 [22] Filed Apr. 14, 1970 [45] Patented Aug. 3, 1971 [32] Priority May 27,1969

[33] Great Britain [3|] 26636/69 [54] ELECTRICAL SWITCHES FOR USE IN STARTER Primary Examiner-G. R. Simmons Attorney-Holman, Glascock, Downing & Seebold ABSTRACT: An electrical switch is for use in an internal combustion engine starting mechanism of the kind including a starter motor, a pinion driven by the starter motor and engageable with a toothed wheel on the engine, and a solenoid for moving the pinion into engagement with the toothed wheel, the solenoid including an armature having an inner part for moving the pinion and an outer part coupled to the inner part. A switch of this kind includes a housing and first, second and third fixed contacts secured in the housing in spaced relationship and lying in a common plane. A movable carrier is mounted for movement in a direction at right angles to the plane of the fixed contacts and a conductive bridging piece is resiliently mounted on the carrier and is urged to lie in a plane parallel with the plane of the fixed contacts. A sleeve slidably mounted in the housing is engaged at one end with the carrier and projects at its other end from the housing for engagement with the outer part of the armature. A push rod is slidable within the sleeve and projects at one end from the sleeve for engagement by the inner part of the armature, resilient means urging the sleeve and the push rod outwardly. A movable latch member is movable by the push rod and is resiliently urged to a position wherein it projects above the plane of the fixed contacts to prevent the bridging piece engaging the third fixed contact during movement of the carrier towards the fixed contacts. The arrangement is such that in use upon energization of the solenoid the outer part of the armature moves the carrier through the sleeve towards the fixed contacts, the bridging piece engaging the latch member and thus being tilted relative to the carrier during further movement of the carrier. The bridging piece in its tilted condition engages the first and second fixed contacts to complete a first circuit of the starter motor and the latch member is then moved by the push rod when the pinion of the starter motor is fully engaged with the toothed wheel of the engine to permit the bridging piece to return to its original position with respect to the carrier so as to engage the third fixed contact to complete a second circuit of the starter motor. The second circuit when completed causes energization of the starter motor at a full torque value while completion of the first circuit causes energization of the starter motor at a reduced torque value.

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INVENTOR 614/42 I ORNEYS ELECTRICAL SWITCHES FOR USE IN STARTER MOTORS lFOR LC. ENGINES This invention relates to electrical switches for use in internal combustion engine starting mechanism of the kind including a starter motor, a pinion driven by the starter motor and engageable with a toothed wheel on the engine, and a solenoid for moving the pinion into engagement with said toothed wheel, said solenoid including an armature comprising an inner part movable axially to move the pinion, and an outer part surrounding said inner part and movable axially in response to energization of the solenoid, said outer part being coupled to said inner part through a spring so that said inner part normally moves with said outer part and said spring permitting said outer part to move relative to the inner part when the inner part is held against movement by tooth'to tooth engagement of the pinion and said toothed wheel.

According to the invention, an electrical switch for use in a starting mechanism of the kind specified includes, a housing, first, second and third fixed contacts secured in the housing in spaced relationship and lying in a common plane, a movable carrier mounted for movement in a direction at right angles to the plane of said fixed contacts, a conductive bridging piece resiliently mounted on said carrier and urged to lie in a plane parallel with the plane of said fixed contacts, a sleeve slidably mounted in the housing and engaged at one end with said carrier and projecting at its other end from the housing for engagement by said outer part of said armature, a push rod slidable within said sleeve and projecting at one end from the sleeve for engagement by said inner part of said armature, resilient means urging said sleeve and said push rod outwardly, and a movable latch member resiliently urged to a position wherein it projects above the plane of the fixed contacts and prevents said bridging piece engaging said third fixed contact during movement of said carrier towards said fixed contacts, said latch member being movable by said push rod, and the arrangement being such that in use upon energization of the solenoid said outer part of the armature moves said carrier through said sleeve towards the fixed contacts, said bridging piece engaging said latch member and thus being tilted relative to the carrier during further movement of the carrier, the bridging piece in its tilted condition then engaging the first and second fixed contacts to complete a first circuit of the starter motor and said latch member being moved bysaid push rod when said pinion of the starter motoris fully engaged with the toothed wheel of the engine to permit said bridging piece to return to its original position with respect to the carrier so as to engage the third fixed contact to complete a second circuit of the starter motor, said second circuit when completed causing energization of the starter motor at a full torque value while completion of said first circuit causes energization of the starter motor at a reduced torque value.

In the accompanying drawings,

FIG. 1 is a sectional view of an electrical switch according to one example of the invention,

FIG. 2 is a sectional view on the line 2-2 in FIG. 1, and

FIG. 3 is a diagrammatic view of a starting mechanism for an internal combustion engine.

Referring to the drawings, the switch includes a synthetic resin molded housing 11 which is adapted to be secured to the casing 12 of a starter motor solenoid 10. Adjacent its ends remote from the casing 12, the housing 11 carries three angularly spaced

fixed contacts

13, 14, 15, the contact surfaces of the contacts 13, M, 15 lying in a common plane generally at right angles to the axis ofthe casing 12, and each ofthe fixed contacts including a portion which extends through the wall of the housing 11 and defines an external terminal. The housing 11 is closed by a mild steel plate which constitutes a partition wall 16 between the housing 11 and the casing 12, the partition wall carrying a hollow pole piece 17 which extends axially into the casing 12. Slidably mounted in the pole piece 17 and extending into the casing 12 at one end, and extending into the housing 11 at its other end is a metal sleeve 18 which is urged towards the casing 12 by a compression spring 19 acting between the housing 11 and an integral shoulder formed in the bore of the sleeve 18. Within the housing 11 the sleeve 18 is formed with an external shoulder 21 and carried by the sleeve 11 in abutting engagement with the shoulder 21 is a molded, insulating carrier 22, the carrier 22 being secured to the sleeve 18 by deforming the end of the sleeve 18 outwardly. An insulating washer 23 is trapped between thedeformed portion of the sleeve 18 and the carrier 22, and loosely mounted on the carrier 22 is a copper bridging piece 24. The washer 23 lies generally at right angles to the sleeve 18, and the bridging piece 24 is urged against the washer 23 by three angularly spaced springs 25 acting between the bridging piece 24 and the carrier 22. Thus, the bridging piece 24 is urged by the springs 25 to lie generally parallel with the plane of the fixed contacts l3, 14, 15.

Slidably mounted within the sleeve 18 and projecting at its ends from the sleeve 18 is a metal push rod 26, the rod 26 being urged towards the casing 12 by a spring 27 acting between the end of the spring 19 and a shoulder 26:: on the rod 26, the sleeve 18 being formed with an internal shoulder against which the shoulder 26a of the rod 26 abuts. The spring 27 surrounds the rod 26, and the bore through the sleeve 18 is formed with clearance to accommodate the spring 27, and moreover, the spring 27 is of a much lower rate than the spring 19. At its-end remote from the casing 12 the housing 11 is formed with a recess 28 which is partially closed by an internal shoulder 29 against which one end of the spring 19 abuts. Positioned within the recess 28 on the side of the shoulder 29 remote from the casing 12 is one limb 32 of a crank lever 31. The other limb 33 of the lever 31 extends towards the bridging piece 24, and the lever is pivotally mounted, intermediate its ends, on the wall of the housing 11. A hairpin spring acts between the lever 31 and the housing 11, and urges the lever 31 to pivot to a position wherein the limb 33 of the lever extends generally parallelwith the sleeve 18, and the limb 32 thereof extends generally at right angles to the sleeve 18, the limb 32 engaging the shoulder 29 to prevent further movement of the lever under the action of the hairpin spring. The limb 33 of the lever 31 is so dimensioned that in the rest position of the lever 31, the free end of the limb 33 is closer to the bridging piece 24than are the

fixed contacts

13, 14, 15.

In use, the armature of the solenoid 10 is slidably mounted within the casing 12, the armature including an outer sleeve 34 which is attracted towards the pole 17 when the solenoid is energized, and an inner shaft 35 which is coupled, at one end, to the outer sleevethrough, springs 36, and coupled at its other end through a lever arrangement 37 to the pinion 38 of a starter motor 39. The arrangement is such that when the solenoid 10 is energized the armature thereof is drawn towards the pole piece 17 thereby moving the pinion 38 of the starter motor 39 towards a toothed wheel 41 on the engine with which the starter motor is associated. Assuming that the pinion 38 moves into full engagement with the toothed wheel 41 without any obstruction, then the shaft 35 and the sleeve 34 of the armature will move as one. However, should the pinion 38 abut against the'toothed wheel 41 in tooth to tooth engagement, then the shaft 35 will be arrested after moving a short distance, and the sleeve 34 will continue to move, the springs 36 coupling the shaft 35 and the sleeve 34 being compressed.

The fixed contact 13 of the switch is, in use, electrically connected to oneterminal of a DC source, the other terminal ofthe DC source being earthed. The fixed terminal 14 is electrically connected through one of the'four field windings of the starter motor 39 to earth, and the fixed contact 15 is elec trically connected through the other three field windings of. the starter motor 39to earth.

The operation of the switchis as follows. When the solenoid 10 is energized, the armature of the solenoid starts to move towardsthe pole piece IV'ag'ainst the action of an armature return spring (notshown )and the shaft 35 of the armature engages the rod 26 and moves the rod 26 relative to the sleeve 18 until the sleeve 34 of the armature engages the sleeve 18 whereafter the sleeve 18 and the rod 26 are moved together, the pinion 38 of the starter motor 39 being moved towards the toothed wheel 41 of the engine. During this movement, the carrier 22 together with the bridging piece 24 are being moved towards the

fixed contacts

14, 15, 16. The dimensions of the parts of the switch and the armature are such that when the armature has completed its full stroke, the bridging piece 24 will be in engagement with the

contacts

13, 14, 15.

Assuming that the pinion 38 engages the toothed wheel 41 in tooth to tooth engagement, then the pinion 38 and the shaft 35 of the armature will be arrested, and so the rod 26 will cease to be moved by the shaft 35. However, the sleeve 34 of the armature will continue to move, thereby stressing the springs 36 and the sleeve 18 and the carrier 22 will continue to move with the sleeve 34 of the armature, and will move relative to the rod 26 until the internal shoulder of the sleeve 18 engages the shoulder 26a of the rod. The rod 26 will then be moved with the sleeve 18 since the shoulder 26a of the rod 26 is abutting against the internal shoulder of the sleeve 18. The limb 33 of the lever 31 is at this time adjacent the contact 15, and closer to the bridging piece 24 than the contact and so the movement of the sleeve 18 will move the bridging contact 24 into engagement with the limb 33 of the lever 31. Further movement of the sleeve 18 will cause the bridging piece 24 to tilt relative to the carrier 22 compressing some of the springs since the bridging piece 24 is engaged with the limb 33, and so that bridging piece 24 will only engage the

contacts

13, 14. The bridging piece 24 completes the circuit between the

contacts

13, 14 thereby energizing said one field winding of the starter motor 39 and operating the motor in a low torque condition. Thus the pinion 38 of the starter motor will be rotated relative to the toothed wheel 41, and the tooth to tooth engagement of the pinion 38 and the toothed wheel 41 will be broken. The pinion will then be moved into full engagement with the toothed wheel 41 under the action of the springs 36, and'the shaft 35 of the armature will be moved towards the rod 26. The length of the rod is such that it will be engaged by the shaft 35 before the shaft 35 has completed its full movement under the action of the springs 36 and so the rod 26 will be moved by the shaft 35 relative to the sleeve 18, towards the end of the housing 11 remote from the casing 12. The bridging piece 24 is formed with a slot adjacent the point at which the limb 33 of the lever 31 engages the bridging piece 24, and the rod 26 is so dimensioned that as the pinion 38 achieves full engagement with the toothed wheel 41 then the rod 26 strikes the limb 32 of the lever 31, thereby pivoting the lever 31 relative to the housing and moving the limb 33 of the lever 31 into the slot in the bridging piece 24. When the lever 31 is pivoted, the bridging piece 24 is no longer spaced from the contact 15 by the limb 33, and so is moved by the springs 25 into engagement with the contact 15 in addition to the contacts l3, 14. Thus when the pinion 38 is in full engagement with the toothed wheel 41, the bridging piece 24 is permitted to complete also the circuit through the remaining three field windings of the starter motor 39 so that the starter motor is operated at high torque and cranks the engine to start the engine.

When the solenoid 10 is deenergized, the armature return spring moves the armature away from the pole piece 17, and the springs 19, 27 return the sleeve 18 and the rod 26, together with the carrier 22 and the bridging piece 24, to their original positions, thereby breaking the circuits through the windings of the starter motor 39. It will be appreciated, that since the

contacts

13, 14, l5'lie in the sameplane, then both circuits of the motor will be broken simultaneously. in the rest position of the carrier 22 the bridging piece 24 is spaced from the limb 33 of the lever 31, and so the lever 31 returns to its original position in readiness for a further operation.

Upon energization of the solenoid 10 should the pinion 38 of the starter motor have moved immediately into full engagement with the toothed wheel 41 of the engine, then the shaft and sleeve of the armature would have moved as one, thereby moving the sleeve 18 and the push rod 26 to cause the closure of the

contacts

13, 15, fractionally after the closure of the

contacts

13, 14.

In the preferred embodiment the lever 31 is formed from insulating material, but it is envisaged that if desired the end of the rod 26 which engages the lever 31 could carry an insulating cap so that the lever 31 need not be formed from insulating material.

lCLAlM:

1. An electrical switch for use in a starting mechanism of the kind specified including a housing, first, second and third fixed contacts secured in the housing in spaced relationship and lying in a common plane, a movable carrier mounted for movement in a direction at right angles to the plane of said fixed contacts, a conductive bridging piece resiliently mounted on said carrier and urged to lie in a plane parallel with the plane of said fixed contacts, a sleeve slidably mounted in the housing and engaged at one end with said carrier and projecting at its other end from the housing for engagement by said outer part of said armature, a push rod slidable within said sleeve and projecting at one end from the sleeve for engagement by said inner part of said armature, resilient means urging said sleeve and said push rod outwardly, and a movable latch member resiliently urged to a position wherein it projects above the plane of the fixed contacts and prevents said bridging piece engaging said third fixed contact during movement of said carrier towards said fixed contacts, said latch member being movable by said push rod, and the arrangement being such that in use upon energization of the solenoid said outer part of the armature moves said carrier through said sleeve towards the fixed contacts, said bridging piece engaging said latch member and thus being tilted relative to the carrier during further movement of the carrier, the bridging piece in its tilted condition then engaging the first and second fixed contacts to complete a first circuit of the starter motor and said latch member being moved by said push rod when said pinion of the starter motor is fully engaged with the toothed wheel of the engine to permit said bridging piece to return to its original position with respect to the carrier so as to engage also the third fixed contact to complete a second circuit of the starter motor, said second circuit when completed causing energization of the starter motor at a full torque value while completion of said first circuit causes energization of the starter motor at a reduced torque value.

2. A switch as claimed in claim 1 wherein said latch member is in the form of a cranked lever having first and second limbs, said lever being resiliently urged to a position wherein said first limb extends generally at right angles to said sleeve and said second limb extends generally parallel to said sleeve and above the plane of the fixed contacts.

3. A switch as claimed in claim 2 wherein said bridging member is formed with a slot so that when said lever is pivoted by said push rod said second limb of the lever is moved into said slot to permit said bridging member to return to its original position relative to the carrier so as to engage said third fixed contact.