US2813206A - Integral positive engagement starter - Google Patents

Description

Nov. 12, 1957 A. E. JENSEN 2,813,206

INTEGRAL POSITIVE ENGAGEMENT STARTER Filed March 19, 1956 AEJENSE/V INVENTOR. 6 277% A TOR/VEYS United States Patent Ofiice 2,813,206 Patented Nov. 12, 1957 Arvid E. Jensen, Ypsilanti, Mich, assignor to Ford Motor Company, D'earborn, Mich, a corporation of Delaware Application March 19, 1956, Serial No. 572,538 2 Claims. (Cl. 290-38) This invention pertains to a motor vehicle integral posi tive' engagement starter and more particularly to astarter which utilizes one of thefield coils in the starter motor to effect the, engagement of the starter pinion with the ring gear of aflywheeL.

-It is an object of this invention to provide a simplified construction for a positive starter motor pinion assembly motivator. Itis an object of this, invention to provide a starter motor construction wherein the fieldcoils are used to attract a plunger which motivates .an arm which is con nected-to starter motor pinion, effectinga driving relation between said pinion and an engine turning means such as the flywheel. It is a further object of this-invention to provide a construction where there are means to divert the starting current wholly through the field coils bypassing the armature thereby providing anincreased amount of flux for attracting the above mentioned arm and restrict armature revolution until the armhas been moved and the pi-nion andcfiywheel have been engaged or prepared'for engagement.

Other objects and advantages ofth'is i-nvention will be made more apparent as this description proceeds, particularly when considered in connection withthe accompanying-drawings "wherein: a

Figure 1 shows-an embodiment of invention in side elevation with a portion cutaway;

Figure 2 shows the assembly of Figure '1 viewed from an V Figure 3 isa schematic wiring-diagram for an embodimen't of thisinvention; and

Figure 4 is a schematic wiring diagram showing a variation of Figure 3.

In this embodiment, a bellcrank is pivoted to a starting motor housing and this bellcrank has a plunger arm and a bifurcated arm with each prong of the bifurcated arm having an inwardly extending slotted flange with a pinion rim loosely fitting into the slots although the connection between the pinion and arm may take many forms. The plunger is adapted to fit into a formed core in the motor frame and field coils and acts as a pole shoe when drawn into the core. The slots fit about the rim of a member which urges the starter motor pinion into driving engagement with the motor vehicle engine flywheel thereby turning said flywheel in preparation for starting of the engine. When current is applied to the field coils, the plunger is attracted rotating the bellcrank and forcing the pinion assembly into engagement with the flywheel. When the starter is de-energized, stopping current flows through the field coils, a. spring returns the bellcrank to its initial position thereby allowing for disengagement of the starter motor pinion from the flywheel. An overrunning clutch is preferably placed between the starter motor pinion and the armature shaft so that in the event that the starter is applied after the engine has become self sustaining, the armature will not be driven at excessive speeds. This invention may also be provided with a switch which bypasses the armature sending full starting current through the field coils. This switch is opened by the plunger arm of the bellcrank when it has nearly completed its travel into the field coil thereby sending full current through the armature and turning the pinion with full torque. Bypassing the armature current until the switch is opened not only provides a large current through the field coils thereby aiding in attracting the plunger into the core but restricts the torque applied tothe pinion during engagement with the. flywheel thereby providing a smoother mesh. The pinion is held in engagement until the starting circuit is opened thereby providing the additional advantage of a positive start.

Looking at Figure 1 is seen a starter motor assembly incorporating an embodiment of this invention. Starting motor 21 has armature. shaft 22 which is journaled in bearing 23. Pinion assembly 24 is attached to armature shaft 22 by means of a loose helical spline barrel 27 so that it can rotate and slide longitudinally with and on shaft 22.. An overrunning clutch is placed between barrel 27 and shoulder 26 of pinion 24 so that a high rotation of pinion 24, such as that as would be experienced when the engine becomes self sustaining, will not turn the armature Latex-cessive speeds. Spring 30 is placed about barrel 27 of pinion assembly 24 and abuts against shoulder 26 and collar 28 which is slidably mounted on barrel 27. Collar 28is spring-urged against shoulder 52 which is fixed to shaft 27. Bellcrank .31 is pivoted at 32 to the starter motor housing and the vertical arm of bellcrank 31 is bifurcated'and each prong is provided with an inwardly extending slotted flange 19 which rides on rim 20 of collar 28. The horizontal arm of bellcrank 31 is provided with plunger 34 which reciprocates in core 35 which is formed through field coil windings 36.- Spring return 37 urges bellcrank 31 to its initial position as shown in Figure 1. Arm 38, opening switch, is operated by the horizontal armof bellcrank 31in its lattermost travel into core 35. Thrustbearing Snapring 33 snaps about a groove on shaft 22.:and against the end assembly. In Figure 2 is shown-an end view of the relationship between bellcrank 31 and :starter motor 21 and also is cutaway to show the engagement :between bifurcated arm of bellcrank 31 and rim 20. Also shown is the engagement between pinion 24-and flywheel 25, the teeth of which are tapered to provide .a more certain engagement.

In Figure 3 is shown a schematic wiringdiagram for an embodiment of this invention. Battery 40 supplies potential to field windings 41 which are connected at 42 and 43 to brushes 47 which are connected through commutator to the armature. Brushes 48 connect the armature through commutator 45 to ground 51. Connection 42 is connected to ground 46 through switch 44 which is opened by arm 38 when bellcrank 31 and plunger 34 are drawn downwardly by field coil 36.

In Figure 4 is shown the connection between 42 and ground 46 with resistance added.

The operation of this embodiment is as follows. Current is sent through field coils 36 by the motor vehicle battery when the starter button or switch is turned on. A field is set up in the center of field coil 36 which attracts plunger 34 which may be of a ferrou material. This downward movement of the horizontal arm of bellcrank 31 imparts a rightwardly movement to the vertical arm of bellcrank 31 thereby causing collar 28 to be moved rightwardly compressing spring 30 under the pressure of roller 33 in groove 29. Pinion 24 is moved rightwardly by the force of spring 30. If the teeth in pinion 24 are not aligned with those of flywheel ring gear 25 at first, spring 30 will be compressed supplying and storing necessary force to urge proper engagement between the teeth of pinion 24 and those of flywheel 25 when they do come into alignment. The teeth on pinion 24 and flywheel 25 are chamfered to receive each'other readily. The fact that the starting motor frame is saturated with flux momentarily on the first surge of current through the field coils aids in drawing plunger 34 into core 35; Once the plunger 34 is so drawn into core 35 it remains there during the entire period of starter motor activation thereby providing field coil 36 with a complete pole shoe and also keeping pinion 24 engaged with flywheel ring gear 25. When starter motor switch 50, seen in Figure 3 is opened manually or automatically, field coil 36 becomes de-energized and spring 37 forces the horizontal arm of bellcrank 31 upwardly imparting a leftwardly movement to collar 28 which abuts shoulder 52 on barrel 27 and pinion 24 is drawn out of engagement with flywheel ring gear 25. The helical splined connection aids in driving pinion 24 into full engagement with flywheel ring gear 25 after the initial engagement has been made. Also, the engagement is more readily broken when the engine becomes self sustaining. V

In Figure 3 is shown a wiring diagram for an embodiment of this invention including switch 44 and ground 46. Switch 44 supplies certain additional advantages. When starter switch 50 is manually closed, battery potential is applied through field coils 36, 41 and switch 44 which is closed during non-operation of the starting motor provides a low resistance path to ground from connection 42 thereby bypassing the relatively high resistance 'path offered through brushes 47, commutator 45 and the armature. This sends very high current through field coils 36, 41 additionally aiding in quick and complete traction of plunger 34 into core 35. Near the end of plunger 34 travel, bellcrank arm 31, contacts arm 38 opening switch 44 thereby sending full current through brushes 47, commutator 45 and the armature to ground 51. In this manner, little or no torque is developed in the armature during the movement of bellcrank 31. A resistance may be placed between connection 42 and ground 46 such as resistance 55 in Figure 4 so that a slight current is diverted through the armature turning armature shaft 22 at a low speed and low torque thereby facilitating engagement between pinion 24 and flywheel ring gear 25-by providing multiple alignments between the teeth of pinion 24 and flywheel ring gear 25.

Itwill be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

What is claimed is:

1. An internal combustion engine starter assembly comprising a frame, a field coil supported on said frame, an armature rotatably mounted in said frame, an armature driven thereby, said pinion being engageable with engine crankshaft turning means, a bell crank having one end adjacent said pinion and the other end attached to a plunger,

and an opening through the frame to permit the bell crank to carry the plunger through the frame and into the field coil, said bell crank being spring biased to move the plunger away from the field coil and frame, the end of the bell crank remote from the plunger and adjacent the pinion being connected to the pinion through a spring whereby the pinion will be moved into engagement with the crankshaft turning means when the plunger moves through the frame and into the field coil.

2. An internal combustion engine starter assembly comprising a frame, a field coil supported on said frame, an armature rotatably mounted in said frame, an armature shaft supporting said armature, an armature shaft pinion slidably mounted, on the armature shaft and rotatably driven thereby, said pinion being engageable with engine crankshaft turning means, a .bell crank having one end adjacent said pinion and theother end attached to a plunger,

' and an opening through the frame to permit the bell crank to carry the plunger through the frame and into the field coil, said bell .crank being spring biased to move the plunger away from the field coil and frame, the end of the bell crank remote from the plunger and adjacent the pinion being connected to the pinion through a spring whereby the pinion will be movedinto engagement with the crankshaft turning means when the plunger moves through the frame and into the field coil, the armature being normally electrically short cir-cuited by a shunt, said shunt being opened by passage of the plunger into the field coil.

7 References Cited in the file of this patent UNITED STATES PATENTS 1,301,478

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