US2081760A - Engine starting mechanism - Google Patents

Description

May 25, 1937. 'R M. NARDQN'E ENGINE STARTING MECHANISM] l Filed March 22. 1930 2 Shets-Sheet 1 May 25,1"937-- R.l MZNARDQN l 2,081,760

ENG-INE STARTNG MECHANI SM Filed March 22. 1930 2 Sheets-Sheet 2 Gttomeg- Patented May 25, 1937 UNITED STATES PATENT OFFICE EN GINE. STARTING MECHANISM Romeo M. Nardone, East Orange, N. J., assignor to Eclipse Aviation Corporation, East Orange, N. J., a corporation of New Jersey Application March 22, 1930, Serial No. 438,220

6 claims. (ci. 121-37) This invention relates to starting apparatus suitably supported and housed within a substanfor internal combustion engines. tially cylindrical casing section 4 which is de- One of the objects of the invention is to protachably connected to the housing or crankcase Vide novel engine starting mechanism that is 5 of the engine to be started by suitable means simple and rugged in structure, light and comsuch. as screws 6, while the power actuating pact, and especially well adapted for use with means are in turn suitably housed and supaircraft engine installations. ported in a second casing section 'l which is de- Another object is to provide an engine starter tachably connected to casing section 4 by any which embodies a novel and efficient fluid pressuitable means (not shown). Section 'l is open sure engine in combination with a booster magat its outer end in order to facilitate assembly 10 neto eiective during operation of the starter to andmaintenance of the power actuating means, augment or displace the normal ignition means and is provided with an end plate 8 detachably of the engine being started. secured thereto by any suitable means and form- A further object is to provide a uid pressure ing a closure for the casing, a bearing for the actuated engine starter in which the engineshaft of the power actuating means, and dis- 15 engaging member is adapted to be automatically tributing passageways for the motive fluid. moved into cranking engagement by the pressure The power actuating means preferably comof the fluid admitted to the fluid pressure actuatprises a fluid pressure engine or motor, the ing means. The above and other objects will crankshaft of which is drivably connected to the appear more fully in the detailed description of driving or engine-engaging member of the 20 the invention which follows'. starter, through a suitable reduction gear train One embodiment of the invention is described and other drive transmission means. In the form and illustrated in the accompanying drawings, shown, a plurality of radially arranged cylinders, but it is to be expressly understood that these one of which is shown at 9, are secured by any drawings are fOl the DUIDOSS Of illllSlJIatOll Only. suitable means (not shown) to the outer end of 25 and are not to be construed as a denition of casing section 1, the upper ends of the cylinders the limits of the invention, reference being had extending radially from said casing. There may for this purpose to the appended claims. be any suitable number of these cylinders ar- In the drawings: ranged singly or in pairs but preferably three u Fig. 1 is a longitudinal sectional view of one cylinders are employed. Each cylinder 9 is 30:

` form of the present invention, taken on line provided with a cylinder liner l0 which extends |-2 of Fig. 2; within casing 'land forms an expansion chamber Fig. 2 is a transverse sectional View taken on Il within which a piston l2 is reciprocated, said line 2-2 of Fig. 1; and liner being held in its proper position within the '35 Fig. 3 is a drawn out perspective view of a casing by means of a shoulder I3 which is 35 piston of the ud pressure engin@v and a portion clamped between cylinder casting 9 and casing of its cylinder. section 1.

Referring now to the drawings, wherein like Novel means are provided for reciprocating reference characters indicate like parts throughpistons l2, which means do not require any me- 40 out the several views, the embodiment of the chanical connection between the pistons and the 40 present invention shown therein comprises an crankshaft but only a surface contact between engine starter of the type having a` driving or these members. As illustrated herein and also engine-engaging member which is adapted for in my co-pending application No. 6,555 filed Febadvancement into cranking engagement with a ruary 14, 1935 (to which latter application refmember of the engine to be started, and for erence is to be had for claims to this feature), 45 cranking actuation thereafter by power means the crankshaft is built up of two main elements through a suitable train of reduction gearing It and l5, each of which comprises a shaft porand other drive transmission means, the power tion Ma and lLia, a crank pin portion and aY means comprising a novel fluid pressure engine, counterweight portion Mc and 50. These two n the pressure of the fluid supplied to which is also elements of the crankshaft are secured together 50 adapted for causing movement of the driving by any suitable means such as a `screw I6 passing member into cranking engagement with the through the crank pin portions. Shaft portion engine member. lila is suitably journaled as by means of a roller In the form shown, the driving member, drive bearing El in a boss I8 formed in the inner face transmission means, and reduction gearing are of casing section 1, while shaft portion ld is suitably journaled as by means of a ball bearing I9 in a boss 25 formed integrally with and centrally of end plate 8. Piston I2, which is made of very light material and left hollow inside in order to reduce its weight to a minimum, may be provided, if desired, with a central web or rib 2| formed integral therewith and extending a substantial distance below the plane of the bottorn edge of the piston for the purpose of contacting with the crankshaft. As shown more clearly in Fig. 3, web 2| is thicker at its sides, which form an extension of the surface of piston l2, than it is in its center portion, and is provided at its bottom with an enlarged shoe retaining portion 22 which is suitably grooved to receive a metal bearing shoe 23, the bottom of which is suitably rounded for a bearing contact with the outer race of a roller bearing 24 which surrounds the crank pin formed by the crank pin portions of crankshaft elements I4 and I5.

Since web 2i, 23 extends transversely across piston I2 on a diameter thereof, and since this web must contact with roller bearing 24 and at times extends between counterweight portions I 4c and |50, it is desirable that suitable means be provided to prevent piston I2 from turning about its axis within the cylinder. For this purpose, a pin 25 (Figs. 2 and 3) having an enlarged cylindrical head 25 and a flattened portion 21 projects through a hole in the lower portion of cylinder liner Il), the flattened portion 2l engaging a longitudinal groove 28 formed in the outer surface of piston I2 and web 2l. A groove 29 is formed in the inner surface of casing section 'l to accommodate the enlarged head 26 of pin 25, which construction not only allows the independent assembly of the cylinder 9, liner Il?, and piston I2, and prevents the piston from 'turning relative to the liner, but also prevents the entire liner and piston assembly from turning after assembly relative to the cylinder and casing section 1.

Suitable means are provided for supplying and exhausting a motive fluid to the above described fluid pressure engine, said means, in the present embodiment, comprising passageways disposed within casing section 1, end plate 8, and cylinders S, and utilizing the shaft portion |50I as a distributing valve. As shown, each of the cylinders 9 is provided with a channel Sil opening into the top of expansion chamber II through a port 3| formed in liner Iii, which channel is a continuation of a similar channel 32 formed in end plate 8. These channels act as both intake and exhaust passages for the cylinders. A main supply passage 33 and an exhaust opening 34 are also provided in end plate supply passage 33 being suitably connected, as by means of a supply pipe 35 and a main control valve (not shown) in said pipe which may be conveniently located as in the cockpit of an aeroplane, to a source of fluid under pressure (not shown), such as a compressed air tank, while exhaust passage 34 may discharge directly into the atmosphere. Main supply passage 33 and channel 3l), E32 lead to the interior of boss 20 within which shaft portion I5a of the crankshaft is journaled. Interposed between the interior of said boss and the crankshaft, and xedly secured to the former, is a valve bushing 36 which is provided with a plurality of ports registering with the respective passages in end plate 8. A main supply port 3l registers with passage 33 and extends annularly around the interior of bushing 36, and a plurality of cornbined supply and exhaust ports 38 register with passages 3i).

Shaft portion i551, of the crankshaft, which extends within bushing 3B and rotates relative thereto, is provided with a pair of longitudinal grooves or passages such that as it rotates with bushing 36 it performs the function of a distributing valve. For this purpose, a supply groove 39 is provided intermediate the ends of shaft portion ld, and of sufficient length to conneet main supply port 3l with any of the cornbined supply and exhaust ports 38 whenever the crankshaft is in such a position that said groove registers with one of the latter ports. The second or exhaust groove llil is formed in the outer end of shaft portion i511, suitably located circumferentially on said shaft with respect to supply groove 39, approximately therefrom, and is of sufficient length to connect the ports 38 with the main exhaust opening 34.

The rotation of the crankshaft of the fluid pressure engine is transmitted to the driving or engine-engaging member by suitable means inl cluding a train of reduction gearing and other drive transmission means. The reduction gearing, in the embodiment shown, comprises a large internal gear 4l which meshes with and is driven by a pinion 42 suitably secured to shaft portion Ila of the crankshaft as by splines 43 or a double-D. Internal gear 4I is drivably connected any suitable manner, as by means of a double-D 44, to a hollow stub shaft 45, the inner end of which is rotatably supported in a boss 46 formed in the inner face of casing section 1, and the outer end journaled in a ball. bearing 41, the outer race of said bearing being carried by a rotatable member of the drive transmission means later to be described. An enlarged portion 48 of stub shaft 45 is provided intermediate boss 46 and hub 49 of gear 4|, and prevents longitudinal movement of said shaft and the assembly thereon.

Formed integral with hub 49 of gear 4I is a pinion or sun gear 50 which meshes with a plurality of planetary gears 5|, preferably three in number, the planetary gears in turn engaging with a stationary internal ring gear 52 secured to the interior of casing section 4 in any suitable manner as by means of screws (not shown). Dowel pins 53 preferably extend into casing 4 and ring gear 52 to prevent shearing of the screws. Planetary gears 5| are journaled on bushing 54 surrounding sleeves 55 which are countersunk in and mounted on an annular base plate 56, which forms a part of the drive transmission means later to be described, by means of screws 5l, and are held in proper operative position on the bearings thus formed by means of a retaining ring 58.

The drive transmission means, which includes base plate 56, is adapted to transmit the rotation of the fluid pressure engine crankshaft as received by said plate through the reduction gearing, to a driving or engine-engaging member which is adapted to be moved into engagement with and to crank a member of the engine to be started. In the form shown, base plate 56 is preferably formed integral with a cylindrical driving barrel member 59 which is rotatably supported in an elongated boss l formed integral with and located centrally within casing section 4 adjacent itsconnection with engine casing 5. Driving barrel 59 also carries the outer race of ball bearing 4l previously referred to. Suitable means may be provided to prevent longitudinal movement of driving barrel 59 within boss',

and, in the form shown, comprise a washer 6| abutting the inner end of boss 60 and a snap ring surrounding the inner end of driving barrel 59 and abutting washer 6I.

A driving or engine-engaging member 63 having a clutch jaw 64 is slidably supported in and drivably connected to driving barrel 59 by any suitable means such as splines 65, and is adapted to be moved into engagement with a corresponding clutch jaw 66 formed on a rotatable member ofthe engine to be started, for the purpose of cranking the latter. The splined engagement between driving member 63 and driving barrel 5B providesva positive driving connection between these members and also allows the former to be moved longitudinally into cranking engagement with vengine clutch jaw 66 by suitable means later to be described.

`An oil sealing member 61 is suitably secured betweenthe flanges of starter casing 4 and engine casing 5, and surrounds driving member 63 and the inner end of the drive transmission means to prevent oil from leaking from within engine casing 5 back into the starter mechanism, said member 61 being provided with a washer 68'of leather or other suitable material which is securedthereto by any suitable means such as a retaining ring 69 and rivets 1.

VIt is desirable that the movement of driving member 63 into cranking engagement with the engi'ne'member be automatic', and means have therefore been provided which are actuated by the pressure of the fluid admitted to the fluid pressure engine and which are effective to move driving member 63 into cranking engagement whenever the fluid pressure engine is actuated. In the form shown, an operating rod 1| extends centrally through the bore of stub shaft upon which the reduction gearing is mounted, with its inner end bearing against the outer end of driving member 63. The outer end of operating rod 1| abuts the face of a piston 12 which is housed within a recess 'I3 formed in end plate 8, and is freely slidable therewithin. A small passageway 'M connects the recess 13 with the main supply passage 33 to which the fluid under pressure for operating the fluid pressure engine is supplied by means of pipe 35. With this construction it is apparent that whenever the main control valve (not shown) in sup-ply pipe 35 is opened-Huid under pressure will not only be supplied to the fluid pressure engine but will also act on piston 'l2 to force driving member 63 to theileft, as viewed in Fig. 1, into engagement with the engine member.

It is also desirable, in some instances, to operate a booster magneto or other current means from thestarter'mechanism when the engine is being started so as to insure proper ignition and quick starting, and such a magneto may be drivably connected to the reduction gear train so as to be rotated at a high speed during the cranking operation. In the present embodiment, a booster magneto T5 of any suitable type is mounted on starter casing section l and secured thereto by any suitable means. The shaft 16 of the magneto carries a clutch member 'il which is keyed thereto and held thereon by a nut 18, and which is provided with a plurality of teeth F9 which engage corresponding splines 89 formed on the interior of a second cupped shapedclutch member 6i rotatably mounted in a boss 82 formed in the lower part of casing section A short shaft 33 is made integral with clutch member `8i and has gear teeth formed on its surface intermediate its ends, constituting a pinion 84 which meshes with internal gear 4I. The inner end of shaft 83 is journaled in a suitable strut bearing member 85 which is secured to casing section 1 by any suitable means such as a screw 86. .Pinion 84 and gear 4I constitute step-up gearing driven by the iluid pressure engine and housed within the starter casing, to which shaft 16 of the booster magneto may be drivablyconnected by means of clutch members 'I1 and 6i.

The operation of the apparatus is as follows: The normal at rest position of the parts of the starter mechanism is as shown in Fig. 1, with clutch jaw 64 of driving member 63 disengaged from engine clutch jaw 66. When it is desired to crank the engine with which the starter is associated, the main control valve (not shown) in supply pipe 35is opened, and a motive fluid under pressure is supplied to the iluid pressure engine through the main supply passage 33. From main supply passage 33 the fluid is conducted to o-ne of the cylinders of the fluid pressure engine through main supply port 31, supply groove 39 of shaft portion 15a of the crankshaft, combined supply and exhaust port 33, channels 32 and 3|), and port 3l of the cylinder which is on its pressure stroke. The fluid under pressure enters expansio-n chamber Il and acts upon piston l2 forcing it downward, and, through the contact between bearing shoe 23 and roller bearing 24 of the crank pin, exerts a force on the crankshaft and rotates the same. After the crankshaft has rotated through approximately 180, exhaust groove 46 registers with supply and exhaust port 38 and connects the interior of expansion chamber I I with the atmosphere through port 3l, channels 36, and 32, port 38, exhaust groove 46, and main exhaust opening 34. At this time piston H is being driven upwardly by the action of roller bearing 24 on shoe 23, the positive drive of the crankshaft being derived from one of the other cylinders on its pressure stroke, and the expanded fluid is exhausted to the atmosp-here.

Simultaneously with the admittance of fluid under pressure to the fluid pressure engine, fluid is admitted through passage 'i4 to recess 13, and acts upon piston 'i2 to force operating rod 'Il to the left, as viewed in Fig. 1 and to move driving member 63 and its clutch jaw 6d into cranking engagement with engine clutch jaw 66. Rotation of the crankshaft lli is then transmitted through pinion 42, internal gear M, pinion 53, planetary gears 5i, base plate 56, driving barrel 59, and

splines 65 to the driving member 63, and the r latter is rotated, cranking the engine to be started.

When the engine starts under its own power, engine clutch jaw 66 will overrun clutch jaw 64 and, due to the inclined shape of the teeth thereon, will force clutch jaw 66 and driving member 63 to the right out of engagement with the engine clutch jaw. After the supply of fluid to the fluid pressure engine has been shut oif and the starter mechanism rendered inoperative, the pressure of any fluid which might remain within the passageways of the starter is insufficient, due to leakage and other causes, to force driving member 63 to the left into engagement again with the engine member, particularly in view of the inclination of the jaw teeth and the relatively high peripheral speed of the clutch jaw 66, as contrasted with the zero, or at best negligible, peripheral speed of the clutch jaw 64.

Should a backfire of the engine being started gines.

occur during the starting operation, the various parts of the starter mechanism will be adequately protected against injury since the reverse torque caused by the backfire will be transmitted back through the drive transmission means and reduction gearing to the crankshaft of the uicl pressure engine where the shock will be cushioned due to the compressible character of the motive fluid..

It will be seen from the above description that there is provided by this invention a starter for internal combustion engines which is entirely independent of electrical energy for its operation, and hence well suited for use with engine installations Where it is desired to avoid the use of batteries for starting, such as in large aircraft. The starter described includes as its power operating means, a novel, compact and efficient iluid pressure engine combined with reduction gearing and other drive transmission means for actuating a driving member adapted for automatic cranking engagement with a member of the engine to be started under the action of the fluid under pressure supplied to the fluid pressure engine. The latter includes a novel piston and crankshaft arrangement which requires no direct connection between these elements, and hence allows the use of very light parts without the sacrifice of strength. It will be understood, however, that the usual connecting rods may be employed if desired. Means are also provided for the operation of ignition current means from the gearing or" the starter, another feature which is highly desirable in starters to be used in aircraft enrIhe fluid engine cylinders are arranged intermediate the fluid supply control means and the gearing to secure compactness and light Weight.

It will be obvious that the invention is not limited to the form shown in the drawings, but is capable of a variety of mechanical embodiments. For example, any suitable type of iiuid distribution means may be substituted for the specific arrangement shown and described, and any suitable number of cylinders may be employed in the fluid pressure engine. Likewise, other forms of reduction gearing or clutch mechanism may be substituted for the gear train and magneto driving coupling described herein. Various other changes, which will now appear to those skilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention, and reference is therefore to be had to the appended claims for a denition of the limits of the invention.

What is claimed is:

l. In apparatus of the class described, the combination of a fluid pressure engine having a crankcase, a crankshaft journaled therein and a plurality of radially arranged pistons for actuating a common crank pin of sai-d crankshaft, a driving member adapted to be driven by said engine, said driving member being normally out of engagement with but adapted to be moved into engagement with and to crank a member of the engine to be started, a rod extending through said crankcase in parallelism with said crank shaft, and actuated by the pressure ofthe fluid supplied to said fluid pressure engine for causing said rod to engage and move said driving member into cranking engagement with the engine member, and means for supplying pressure fluid to at least one of said pistons to cause said crankshaft and driving member to begin to rotate simultaneously with the beginning of movement of said driving member into cranking engagement.

2. In an engine starter of the type having a driving member normally out of engagement with but adapted to be moved into engagement with and to crank a member of the engine to be started, the combination of a fluid pressure engine having a plurality of cylinders and a crankshaft, said crankshait having fluid transmitting passages formed therein to distribute the motive fluid to and from said cylinders, a pinion secured to said crankshaft, an annular gear meshing with said pinion and adapted to transmit rotation therefrom to the driving member, a second pinion integral with said annular gear, and a rod extending through said annular gear and pinion, said rod being effective upon actuation of the fluid pressure engine for causing advance of the driving member into engagement with the member of the engine to be started, and means for admitting pressure uid to said cylinders independently of any movement of said rod.

3. In an engine starter of the type embodying a driving member normally out of engagement with but adapted to be moved into engagement with and to crank a member of an engine to be started, the combination with said driving member of a multi-cylinder fluid pressure engine having a crankshaft, means including a reduction gear train for drivably connecting said crankshaft and said driving member, a second shaft adapt-ed to be driven by said gear train, and a fluid pressure actuated member distinct from said driving member and passing centrally through said gear train and adapted to move the driving member into engagement with the engine member simultaneously with actuation of the fluid pressure engine.

Il. In combination with the driving member of a clutch. means including a fluid pressure engine and a reduction gear train for actuating said driving member, and a member distinct from said driving member and passing centrally through said gear train and adapted to urge said driving member into operative position only when a huid under pressure is admitted to the fluid pressure engine.

5. In a device of the class described, a driving pinion, a pair of driven pinions disposed in parallelism therewith, fluid pressure driving means for said first named pinion, an annular gear constituting the sole driving connection from said rst named pinion to each of said driven pinions, one of said driven pinions being integral with said annular gear, a drive controlling rod movable through said annular gear, and means branching from a common conduit through which pressure fluid is supplied to actuate both said rod and said driving pinion.

6. In a device of the class described, an annular member and teeth on its inner surface, a set of driving teeth meshing with said first named teeth., fluid pressure driving means for said first named teeth and a third set of teeth meshing with said rst named teeth, said annular member constituting a sole driving connection from said driving teeth to said third set of teeth, and a pressure fluid actuated drive controlling rod movable through said annular member and common means for conducting pressure uid into position to actuate said rod and driving teeth.

ROMEO M. NARDONE.

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