US2296975A - Engine starting mechanism - Google Patents

Description

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Patented Sept. 29, 1942 UNITED STATES PATENT OFF-ICE ENGINE STARTING MECHANISM Donald M. ,Bergcs, Alpine, N. L, assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 12, 1940, Serial No. 360,989

Claims.

This invention relates to internal combustion engine starting apparatus, and more particularly to engine starting apparatus of the inertia type, wherein there is considerable rotation of the driving elements, for momentum or 'inertia producing purposes, in advance of establishment of torque transmitting connection between said driving elements and the engine crank-shaft. The establishment of such connection is commonly referred to as meshing.

Where the meshing is brought about through the agency of linkage, the actuation of said linkagewhether manually or electro-m'agnetically induced-requires expenditure of considerable energy as it is necessary to overpower a comparatively sturdy opposing element such as, for example, a torsion spring similar to the one indicated by reference numeral I06 in Fig. 4 of the drawings ofPatent No. 1,833,948 granted December 1, 1931. The purpose of this opposing spring, or its equivalent, is to insure a return of the engine engaging clutch or gear element 'to'the 'demeshed position, and/or to insure the retention thereof in the dc-meshed position at all times other than the period of the actual cranking operation; and as the opposition of such spring or its equivalent must be overcome in order to mesh the starter with the engine, it is apparent that considerable force is required. In electromagnetically induced mesh'ingas in the Lansing patent above identified-the current drawn by the electro-magne't is considerable, for the reasons above indicated; and where the meshing is manually effected, the effort required is correspondingly high.

An object of the present invention is to provide, in a starter of the character indicated, a novel method of meshing, involving utilization of previously stored energy to produce the meshing movement, under the control of the operator as to the timeof such meshing movement, whereby there is secured the advantage of delayed meshing (to permit the building up of inertia, or momentum) but without the necessity of introducing a separate source of energy to produce such delayed meshing.

Another object is to provide novel meshing means for an inertias'tarter of the character indicated.

Afurther-object is to provide novel means for converting rotary into rectilinear movement, to produce corresponding rectilinear movement of the engine-engaging member.

Another object is to provide meshing mechaever, being controlled-manually as to the time .of utilization thereof.

These and other objects of the invention will become apparent from inspection of the following specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing:

Fig. 1 is a view, partly in elevation and partly in section, of an inertia starter by means of which the invention may be practiced; and

Fig; 2 is a transverse view along the line 2-2 of'Fig. 1.

Referring to the drawing, there is disclosed a combined hand and'poweractuated starter of the conventional inertia type. As shown, the starterincludes 'a'flywheel 2 constituting the inertia element, and an engine engaging clutch element 3 which is movable into driving engagement with a corresponding clutch member 4 provided on or connecting with the crankshaft or crankshaft extension of the engine to be started. The mechanism is housed within a suitable casing constituted by an inner section 5, intermediate sections 6 and I; and'a motor casing 8, the sections being removably secured together in any suitable manner, and the inner section 5 being provided with a'flange 9 to facilitate the mounting of the starter on the engine crankcase, or in any other suitable location.

The manually operable means for actuating the starter preferably takes the form of a cranking shaft I0 rotatably mounted in intermediate housing section 6, with the outer end thereof projecting from said housing, and provided at its inner end with suitable means, such as a bevel pinion I l, for meshing engagement with a similar pinion I2 .keyed to a shaft l3 constituting an integral extension of'the closed end of barrel 30. The said shaft l3 is further provided with a bushing 14 on which is rotatably mounted the hub of an internally toothed gear l5 coaxially disposed with respect to the flywheel 2, and adapted to mesh with a pinion l6 made integral with a bell shaped member I! provided at its opposite end with a skirt or flange constituting a spur gear l8 adapted to mesh with a pinion IS, the latter being preferably integral with a stub shaft 2'3 to which the flywheel 2 is rigidly secured by suitable nism utilizing centrifugal force; the force, howmeans, such as the key shown at 21; This stub shaft 20 is rotatably supported, as by ball bearings 22, in a suitable hub on a wall 23 extending across the section 6 of the starter casing. The bell-shaped member I1 is in turn rotatably supported, as by means of a stub shaft 25, bearings 26 and 21, in a compound boss 23a formed on wall 23.

The gear I is provided centrally thereof with an integrally formed pinion 59 which constitutes the sun gear for a plurality of planetary gears 5I, one of which is shown in section in the drawing, and one in elevation. These planetary gears 5|, of which three are preferably employed,

spaced at intervals of one hundred and twenty degrees about the sun gear 50, mesh with an internally toothed ring 52 which is rigidly secured in any suitable manner to the inner surface of housing section 5, such as by screws 52a; Each clamped thereto, and also to the barrel as indicated at 62. A retaining ring 66 carried by the outer ends of the screws 55 maintains bearings 53 in their proper positions on sleeves 54.

' A multiple disc clutch is preferably provided in association with the barrel 39 to insure relative rotary movement between the engine engaging member and the train of gearing above described, whereby the latter is protected from damage due to an excessive shock or load. 'As shown, the disc clutch comprises a plurality of inter-leaving discs 19, alternately splined to the inner surface of the barrel 38, and the outer surface of a shell 80, internally threaded to engage a correspondingly threaded screw shaft 15, to be further described. Resilient means, such as a plurality of coiled compression springs 8I, the pressure of which is adjustable by a nut 82 threadedly engaging the end 83 of the barrel, are provided to'press upon a flange 85 on member 8ll,and thus maintain the discs 19 in frictional engagement with a pressure suflicient to. insure transmission of torque from barrel 38 to shell 80, up to a predetermined capacity.

Fitted over the inner end of the starter is a cup-shaped member 89 that is preferably formed of metal and is provided with a flange 9| adapted to be clamped between flange 9 of the starter housing, and the engine flange 92. The inner portion of member 89 is bent inwardly toward clutch member 3, as at 93, and is provided with a central opening which is slightly larger in diameter than the outer diameter of the clutch member 3.

In order to prevent seepage of oil through the central opening in member 89, the latter preferably carries a washer 94 of leather or equivalent material. Normally the inner portion of washer 94 is held in engagement with the adjacent surface of the head of clutch member 3 by means of a metallic washer 95 and a flange sleeve 91.

Havingnow described the construction of a conventional inertia starter of the character to which the present invention is well suited, there remains to be described the novel means for connecting the clutch elements 3 and 4, and for controlling such connecting, or meshing.- In the form shown, centrifugal weights I36 are mounted on the outer ends of bell-cranks I31 pivotally supported in trunnions or bearings provided at angularly spaced intervals (see Fig. 2) about the periphery of a coupling cup I38 that is fastened by screws I39 to the web of flywheel 2 to constitute a part thereof, and has a tongue and groove connection I4I which couples its hub I42 to the armature shaft I43 of the motor 8, to be driven thereby. The inner portions of bellcranks I31 engage the rotatable outer race I46 of a ball-bearing assembly whose inner race I41 is in the form of a head-piece or flanged end fora rod 1 that passes through the central bore in stub shaft 20, and also through the central-bore inscrew shaft 15, to terminate in a .an annular member I5I surrounding coupling cup I38, and having a circumferential groove to receive pins I52 of a yoke I53 that has a boss I54 actuated by a rock-shaft I56 journaled in the starter housing and extending therefrom to receive a lever I51 adaptedfor manual rocking by means of link I58.

The leftward movement of rod II1, under the influence of the bell-cranks I31, is yieldably opposed by coiled compression spring I59, and the extent of the movement is positively limited by the shoulder I21 which is formed on shell by reason of the termination of the threads at the region indicated. This shoulder I21 stops the leftward movement of screw-shaft 15 (and hence ofrod 1) when the stop-nut I26 of the screwshaft assembly reaches a position of abutment with respect to said shoulder I21. Prior to such abutment, however, the spring I28 will have urged jaw 3 into full mesh with engine member 4, in view of the increased pressure which the screw-shaft 15 places upon said spring I28 during its leftward movement.

When the engine acquires sufficient momentum to cause member 4 to over-run member 3, the reverse screw action exerts a thrust upon rod II1 (as does also spring I59) to return it (and weights I36) to the position indicated in the drawing-the weights I36 having meanwhile slowed down with the decelerationof the flywheel. The operator will then return yoke I53 to the restraining position shown, thus restoring the mechanism to its original condition.

What is claimed is:

1. In an engine starter, in combination with an engine-engaging member, rotating means for said engine-engaging member, said rotating means including a flywheel and gear train, and means including weighted members mounted on said flywheel and a rod passing through said gear train for moving said engine-engaging member to engine-engaging position, said means also including a head-piece carried by said rod, and disposed in the path through which said weighted members move by centrifugal action, inresponse to rotation of said flywheel.

2. In an engine starter, in combination with an engine-engaging member, rotating means for said engine-engaging member, means including weighted members mounted on said rotating means for moving said engine-engaging member to engine-engaging position, the manual means for controlling the action of said weighted members and thereby fixing the time of establishment of driving connection between the starter and the engine.

3. In an engine starter, in combination with an engine-engaging member, rotating means for said engine-engaging member, said rotating means including a flywheel and means for starter energy in said flywheel prior to movement of said engine-engaging member to engine-engaging position, means including weighted members mounted on said flywheel for'moving said engine-engaging member to engine-engaging position, and manual means for controlling the action of said Weighted members and thereby fixing the time of establishment of driving connection between the starter and engine.

4. In an engine starter, in combination with an engine-engaging member, rotating means for said engine-engaging member, said rotating means including a flywheel and means for accelerating said flywheel prior to movement of said engine-engaging member to engine-engaging position, centrifugal means for moving said engine-engaging member to engine-engaging position, and manual means for controlling the action of said centrifugal means and thereby fixing the time of establishment of driving connection between the starter and engine.

5. In an engine starter, in combination with an engine-engaging member, rotating means for said engine-engaging member, said rotating means including a flywheel and means for accelerating said flywheel prior to movement of said engine-engaging member to engine-engaging position, centrifugal means for moving said engine-engaging member to engine-engaging position, means normally restraining movement of said centrifugal means in a radial direction with respect to the axis of rotation of said centrifugal means, and manually operable means for withdrawing said restraining means and thereby fixing the time of establishment of driving connection between the starter and engine.

DONALD M. BERGES.

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