US2568404A - Engine starting mechanism - Google Patents

Description

Sept. 18, 1951 R. M. NARDONE ENGINE STARTING MECHANISM Filed March 17, 1947 lllllllllllll llllllllllllll AffOR/VEY Patented Sept. 18, 1951 UNITED STATES, PATENT OFFICE ENGINE STARTING MECHANISM Romeo M. Nardone, Teaneck, N. J assignor to Joseph J. Mascuch, Maplewood, N. J.

Application March 17, 1947, Serial No. 735,277

3 Claims. 1

This invention relates to internal combustion engines, and particularly to the starting of such an engine by application of a starting torque to produce initial rotation.

An object of the invention is to provide a starter adapted for energization by the burning of a powder charge in a breech chamber forming an integral part of the starter housing.

Another object is to provide a starter housing of novel construction, featuring extreme strength and rigidity, thereby facilitating absorption of the torque reaction during the starting operation, and promoting effective motion ,translation between the power piston and the driven sleeve which actuates the engine-engaging member, without resort to translation assisting devices such as anti-friction balls or the like. This feature of the invention assures sufiicient cranking action from a single stroke of the power piston and a single motion translation couplefor example, a single set of inter-engaging screw threads.

Another object of the invention is to provide novel means for transmitting engaging thrust to the engine-engaging member in two stages, in the event of corner contact on first engagement; the novel means including a pair of spring couplings, one of which acts radially and the other axially of the actuating member.

A further object is to provide novel percussion means for setting off the powder charge and thereby starting the fluid pressure generation.

Another object is to provide a novel exhaust valve structure for control of the escape of the pressure fluid after the engine has been started.

Other objects and advantages to be derived from the use of the invention reside in the specific construction, combination and inter-relationship of parts whereby a compact, efficient and easily operated and maintained unit is produced; all of which objects and advantages will appear more clearly upon an inspection of the following specification, with reference to the accompanying drawings wherein:

Fig. 1 is a longitudinal sectional view of a device embodying the invention, but omitting the firing mechanism; the latter being shown in Fig. 2.

In these figures there is shown a unitary device including a sectional housing 5, 6, 1, a power piston 8, a driving screw 3, a driven screw iii, an engine-engaging clutch II, a powder barrel l2, and a firing pin l3 for ignition of the powder pellets II by percussive action against the cap of a cartridge inserted in barrel l2. Housing sections 6 and I are hydrogen-copper brazed, one to the other, and inner housing section 5 is similarly brazed to sections 6 and I, so that its inner flange may better withstand the thrust of ball bearing assembly 21. e

The inner face of section 5 is slotted to receive reaction sleeve I6, to which latter is brazed the splined sleeve 15, along whose splines the driving screw 9 is guided, as it advances with the power piston 8.

Driven screw ID has a thrust ring I! pressed on its forward end. The outer rim thereof is adapted tov engage thrust bearing 2|, and this engagement therefore limits forward (axial) motion of the screw, while permitting free rotation thereof, due to the ball bearing action. The engineengaging jaw clutch H has a shank whose splines slide along the splines 29 of screw I0, being urged into engine-engaging position by the compression spring 3|. Lock ring 32 secures member H against complete separation from the screw splines 29, and chevron packing 33 prevents engine oil entry into the screw chamber; the packing 33 being tightly secured by the action of ring 34 and wavy spring 35, and pressed thereby to sealing position in both radial directions.

Driving screw 9 is locked to the power piston 8 by lock ring 31 and therefore partakes of all axial motion of the piston. The latter has a circumferential rim 38 to retain the packing rings 39 in gas-tight, but sliding engagement with the inner surface of the enclosing cylinder. The cylinder head 30 has a radial recess adapted to receive the cartridge containing the powder pellets i4. Gases are generated by the burning of the powder in pellets l4, and these gases enter the cylinder through openings 44, to advance the piston 8 and screw 9, and thereby rotate the driven screw l6 and the engine-engaging element ll. Prior to such rotation, however, the screw H1 is thrust-forward a sufficient amount to produce engagement of its thrust ring IT with the thrust bearing 2|; this forward thrust being produced by the action of snap ring 5| against the groove 52 cut in the inner bore of screw ID. The snap ring is shiftable into and out of the peripheral groove 53 in the sleeve 54, which sleeve is attached to the piston and moves therewith.

During the above-described initial forward thrust of screw In, one of two events occur: either the jaw H meshes firmly with the engine jaw (not shown) of corresponding tooth contour, or a condition of incomplete mesh arises. In the latter event the attainment of a fully meshed condition awaits the occurrence of the first few degrees of rotary motion, and this occurs as soon as motion translation between parts 9 and I begins, namely, when ring I! engages thrust bearing 2|. These first few degrees of rotary motion shift the jaw ll sufiiciently to permit spring 3| to complete the meshing action; the spring 3| having been compressed to maximum stress as the ring I! moved forward to engage thrust bearing 2|. Continued rotary motion turns the jaw H and thereby imparts rotation to the engine to be started.

As the piston 8 approaches its extreme forward position, disc 6| on the piston engages head 62 of rod 83, and draws the said rod 83 along with it, thus drawing the exhaust valve 64 away from its seat 65 in the housing wall, and por mltting the gases in the cylinder to discharge to the atmosphere by way of exhaust port 66. As the valve opens the snap ring 61 moves radially to engage shoulder 68, and the valve is thus held open by positive restraint, which restraint prevailsuntil the return of piston 8 (under the urge of-spring 40) exerts positive contact pressure on the head of the valve 64, whereupon snap ring 61 moves back into its groove and the valve returns to its closing relationship to seat 65. Lock ring H prevents the ejection of piston 8 by spring 40, on any occasion requiring removal of head 12 from the cylinder. .A bronze ring 73, tapered at its outer diameter, prevents leakage of gases through the threads. A safety disc I4 is held in the head 12 by suitable members 16 and I1, and is adapted to disintegrate in the event of excessive pressure development, to permit escape of the pressure to the atmosphere.

Figure 2 shows the construction of the firing assembly. Firing pin I3 is normally held away from contact with the percussion cap in the cartridge in barrel l2 by a spring 8| bearing against a flange at the lower end of a thin sleeve whose upper end is turned over a shoulder on the pin I3. This spring 8| counteracts the larger spring 82 in its free position. Bell crank 83 carries a spring-pressed pin 84 whose end engages a slot in the skirt of the firing pin l3. Movement of hell crank 83 about its pivot pin 87 first retracts the said skirt and then (when the pin 84 reaches the dash line position) permits the pin l3 to snap forward, under the urge of the compressed spring 82, as soon as pin 84 escapes from the slot in the skirt of the firing pin. The firing .pin, upon springing forward, strikes a sharp blow on the percussion cap of the cartridge, causing explosion of the main powder charge, with resultant creation of fiuid pressure as the liberated gases seek an outlet. These gases pass through openings 44 and apply themselves against the surface of piston 8, causing it to advance, moving sleeve 54 and screw-shaft 9 along with it. Such movement operates the engine-engaging law clutch II, as previously described.

Before the above-described release of firing pin l3 by the manual control 83, the breech is of course locked securely against the lower end of the cartridge barrel l2 in the usual manner.

What I claim is:

1. In an engine starting mechanism, a cylinder having a rigid forward cylindrical extension integrated therewith a driving, non-rotatable screwshaft, an engine-engaging member including a splined shank extending rearwardly of the engine-engaging face, a driven screw-shaft having splines engaging said shank to rotate said engineengaging member, said driven screw-shaft also having a thrust ring secured thereto, means acting through said thrust ring for producing axial, engine-engaging movement of said engine-engaging member, and means rotatably mounted within said forward cylindrical extension of said cylinder for limiting the travel of said thrust ring and thereby limiting the axial movement of said driven screw-shaft.

2. A mechanism as defined in claim 1, wherein said limiting means includes a ball bearing assembly in the path of axial motion of said thrust ring, said assembly serving to facilitate free rotation of said driven screw shaft. 1

3. A mechanism as defined in claim 1, wherein a compression spring is interposed between said thrust ring and engine-engaging member to'insure complete meshing action between the engine-engaging member and the engine, even though corner contact occurs on initial engagement thereof.

' ROMEO M. NARDONE.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,771,776 Dal Lago July 29, 1930 1,903,079 Woolson 1 Mar. 28, 1933 2,045,913 Cofiman June 25, 1935 2,072,608 Smith 11 1 Mar. 2, 1937 2,144,196 Nardone 1 Jan. 17,- 1939 2,189,439 Temple Feb. 6, 1940 2,284,358 Baer 1 1 May 26, 1942 2,295,288 Nardone Sept. 8, 1942 2,299,464 Cofiman Oct. 20, 1942 2,375,029 Nardone May 1, 1945 2,400,878 Dunn May 28, 1946 2,429,863 Wright Oct. 28, 1947 2,454,528 Temple 1 Nov. 23, 1948 FOREIGN PATENTS Number Country Date 197,318 Great Britain Nov.- 20, 1924 274,309 Italy 1 May 17, 1930

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