US2154555A - Engine starting apparatus - Google Patents

Description

April 18, 1939. H. BAER ET AL l ENGINE S-TARTING APPARATUS Filed Aug. l, 1935 5 Sheets-Sheet l ml NN m s Q ma 4 Apri118,1939. 'H BAER ET AL 1 2,154,555

ENGINE STARTING APPARATUS Filed Aug. 1, 1935 s sheets-sheet 2 l 74 54 8.2v /7 i v a3' INVENTORS. #i Howard Bae/- Ma/*/n df fnn @ya/7 /irku VAApril 1s, 1939. H BAER ET AL 2,154,555

ENGINE TARTING APPARATUS Patented Api-.18, 1939 UNITED STATES ENGINE STARTING APPARATUS Howard Baer, Jersey7 City,

Finnegan, New York Aviation Corporatio N.. J., and Martin J.

, N. Y., assignors to Eclipse East Orange, N. J., a corporation of New Jersey Application August l, 1935, Serial No. 34286 5 Claims.

This invention relates to engine starters, and particularly to those of the type having an engine engaging member which is movable to engaging position to impart initial rotary movement to the engine crankshaft, and subsequently retracted, or demeshed when the cranking eifort is discontinued.

An object of the invention is to provide means for holding the engine engaging member in engine engaging position until the engaged engine member has attained a speed greater than that of the engine engaging member, such holding being eected by a novel method of operation which includes the step of utilizing energy derived from the same source as that which supplies the cranking force.

When the source of energy is a uid under pressure, as in the embodiment illustrated in the accompanying drawings, the holding means for the engine engaging member preferably takes the form of a mesh controlling piston movable in response to application of the fluid pressure, and having pressure trapping means associated therewith to hold the piston (and hence the engine engaging member) in the elective position until the engaged-element of the engine runs ahead of i. e., over-runsthe engine member of the starter.

In the illustrated embodiment the starter is shown as of the type including a piston (distinct from the mesh controlling piston above described) reciprocable within a uid receiving chamber, the motion of the piston being converted into rotation of the engine engaging member by suitable trans- 1ating mechanism; but it is to be understood that these drawings are for the purposes of illustration only and are not to be construed as a limitation of the scope of the invention, reference being had for this purpose to the appended claims.-

In the drawings:

Fig. 1 is a longitudinal sectional view of a device embodying the invention;

Fig. 2 is a diagrammatic view snowing one form of pressure generating and contrpl means;

Fig. 3 is a view of a second form of pressure generating and control means;

Fig. 4 is another longitudinal sectional view, but showing the piston in an extreme operative position; and

Figs. 5 and 6 are transverse sectional views through the overrunning clutches.

With reference to the drawings, and more particularly to Fig. l, the piston and engine starting gear unit comprises a body member I having a ange I2 by which it is secured to the engine crankcase I3 as by bolts I4, the ange being conveniently of a size standardized for aircraft engine starters. The engine crankshaft, or other drive shaft (not shown) is provided with an engine jaw II engageable by the starter jaw I as 5 will be later more fully described.

Screw threaded in a quickly detachable manner to an annular flange I6 integral with the body I0 is a cylinder I1 having a closed head I8, and slidably fitted within the cylinder is a piston coml0 prising the head I9 secured to the rotatable cylindrical piston body 20, the piston body and the main starter body lI0 being provided with co-operating helical grooves 2| and 22. A sleeve 2s is internauy drivab1y connected with the pis- 15 ton body 20 by splines 21'and 28 which permit the axial travel of the piston body relative to the sleeve, but restrain these two parts to unitaryrotation. An anti-friction thrust bearing 29 is preferably interposed between the end of the 20 sleeve 26 and a nose piece 30.

The starter jaw I5 is splined for limited axial travel within a second sleeve 3| andis normally retained'in the position shown by a central rod 32 which is connectedto the jaw I5 as by the nut 25 33 and shoulder 34.

This rod has a piston t within the bore of a sleeve 35 which is integral with the cylinder head I8, the head 5I of the rod being exposed to the gas pressure within the cylinder I'I. Trailing 30 from the head 5I is a tail piece 52 having a portion 53 constituting a slide valve adapted to close the port 54 in cylinder I8 when the piston moves forward to a suflcient extent to mesh the parts I5 and II, such forward movement opposed by the spring 56. As-shown the cylinder I8is received within the bore of the externally threaded extension 6I formed centrally of the piston head I 9 and engageable with a correspondingly internally threaded sleeve 62 terminating in 40 a portion 63 of reduced diameter constituting the inner race of an overrunning clutch 64, the outer race being constituted by the extending socket 66 of an internally splined sleeve 3I previously described. This sleeve 3| constitutes the inner race 45 of a second overrunning clutch 68, the outer race of which is constituted by the previously described sleeve 26.

E xhaust ports 36 are uncovered by the piston at the left-hand end of its stroke and an exhaust ring 31 preferably collects the discharge so that it may be led away to any desired point by..a suitable pipe 38. A spring 39 normally maintains the piston at the right-hand end of its travel as shown, and the piston is preferably equipped with a pair of piston rings 4 I. 'I'he cylinder head I8 is provided vwith a pipe 46 which may be connected to the breech of a cartridge iiring mechanism, as in Fig. 3, or to a pressure chamber, as in Fig. 2.

Referring rst to Fig. 2 it will be seen that the pipe 46 terminates in a valve housing 1I enclosing a pressure operated tubular valve member 12 which is apertured, as indicated at 13, to permit the establishment of communication between pipes 14 and 46, the former being in turn connected with a tank 16 constituting a source of fluid under pressure, the initiation of the fio-w of fluid being under the control of a manually A second pipe 18 leads from the cylinder head I8 to the lower chamber 19 of the valve housing 1| and operates to convey fluid to the said chamber 19 to move the piston 8| against the yielding opposition of the spring 82 and thereby eventually open the chamber 19 to the atmosphere by way of the vent 83, a second vent being shown at 84 for the purpose of preventing creation of undue pressure on the upper side of the piston. The corresponding piston 8| of Fig. 3 actuates a pawl 96 engageable with an indexing member 91 to rotate the cartridge container 98 step by step, for successive firing of the cartridges in anysuitable manner, as indicated, for example in the application of Romeo M. Nardone, Serial No. 457,301 filed May 29, 1930.

In order to hold the piston head I9 against rotation, a plurality of rods 9| are caused to extend through apertures in the piston head, the outer end of the rod being i'lxedly secured in the stationary head I8. One of these rods 9| is apertured as indicated at 92 and is also longitudinally bored to permit passage of fluid into the pipe 18 from the space to the right of the piston head I9 when the latter has advanced to the left to a sufcient extent to uncover the said port 92.

The operation of the mechanism so far described is as follows:

Upon valve 11 being opened, the high pressure fluid is conveyed from tank 16 by Way of the open port 13 and pipe 46 to the cylinder I1, and acts both upon the piston head and the central rod 32. There being practically no resistance other than the spring 56 to the movement of the rod,

operable valve 11.

it is instantly advancedto the left thus engaging the engine jaw II. At the same time the piston I9 advances, and enforces a rotary motion on the starter jaw I5 dueto the helical grooves 2l and 22, causing rotation of sleeve 26, and likewise sleeve 3| through overrunning clutch 68. The engine is accordingly turned over and when the piston reaches a point where the exhaust ports 36 are uncovered the iluid pressure will escape and the spring 39 can return the pistn to the normal position shown in the` drawings. At whatever point of the piston travel the engine starts under its own power, it is free to overrun theI jaws I5 due to their sloped or angular formation, and the spline connection of the jaw with the sleeve 3|.

Should the engine fail to so start, there will be no overrunning at the point II, I5, and hence no demeshing of the jaws, for the spring 56 is not strong enough, per se, to return rod 32 against the opposing force of the uid trapped under pressure in the small cylinder I8. The large cylinder I1, on the other hand, is exhausted of all pressure fluid due to the openings 36 and therefore spring 39 returns piston head I9 and its threaded extension 6I, theI return stroke of the latter being translated into a turning of sleeve 62 and a corresponding additional rotational impulse on sleeve 3| and jaw I5, the roller clutch 64 now being effective to drive while clutch 68 overruns. Meanwhile chamber 19 and pipe 18 release the pressure fluid to the atmosphere, through the port 83 and the resulting descent of plunger 8l restores communication between tank 16 and pipe 46. As a result a second charge of pressure fluid acts upon piston head I8 and thus continues the reciprocating movement of threaded sleeves 20 and 6I, and produces a corresponding continuation of the drive to engine member I I, the cycle being repeated Without demeshment of jaw I5, and the process continuing until the trapped uid in small cylinder 35 is released by reason of the overrunning of the jaw II, which overrunning can occur only when the engine fi'resthat is, develops its own motive power. The ring means of Fig. 3 will produce 'a similar multiplication of 'driving impulses, until the cartridge supply is exhausted, or the operator may intervene to stop the firing mechanism before all cartridges are discharged. Likewise, with the system of Fig. 2, it is also intended that the operator intervene to re-close valve 11 to prevent needless expenditure of fluid pressure after demeshment of the jaws II and I5.

What is claimed is:

1. In a device of the class described, the combination with an engine engaging member of means operating successively to drive said engine engaging member, rectilineally moving means for controlling the effectiveness of said successively operating means and means carried by one of said heretofore recited means to cause movement of said engine engaging member Ito engine engaging position.

2. In a device of the class described, the combination with an engine engaging member of means operating successively to drive said engine engaging member, rectilineally moving means for controlling the effectiveness of said successively operating means, means carried by one of said heretofore recited means to cause movement of said engine engaging member to engine engaging position, means for energizing said rectilineally moving means, and means responsive to a demeshing of said engine engaging member to discontinue the energization of said rectilineally moving means.

3. In a device of the class described, the combination with an engine engaging member, of means including a pair of torque transmitting clutches alternately effective to drive said engine engaging member, means including a common rectilineally moving member for actuating said clutches, the eii'ectiveness of said clutches being dependent upon the direction of rectilineal movement of said last named member, and means carried by said rectilineally moving member to cause movement of said engine engaging member to engine engaging position.

4. In a device of the class described, the combination with an engine engaging member, of means including a pair of torque transmitting concentrically disposed screws alternately effective to drive said engine engaging member, means including a common rectilineally moving member for actuating said concentrically disposed screws, the effectiveness of said concentrically disposed screws being dependent upon the direction of rectilineal movement of said last named member, and means carried by said rectilineally moving member to cause movement of said engine engaging member to engine engaging position.

5. In a. device of the class described, the combination with an engine engaging member, of means including a pair of torque transmitting elements alternately effective to drive said engine engaging member, means including a. common rectilinealiy moving member for actuating said elements, the eifectiveness of said elements being ciependenil upon the direction of rectilineal movement of said last named member, and means carried by said rectilinealiy moving member to cause movement of said engine engaging member to engine engaging position.

- HOWARD BAER.

MARTDI J. FINNEGAN.

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