US2135768A - Starting gear for internal combustion engines - Google Patents

Description

Nov. 8; 1938. G. E. RAMSTAD` STARTING GEAR FOR INTERNAL COMBUSTION ENGINES.

2 'Sheets-Sheet 1 Filed July 6, 1936 Gttornegs Nov. 8, 1938. G. E. RAMSTAD STARTING GEAR FR INTERNAL COMBUSTION ENGINES Filed July 6, 1936 2 Sheets-Sheet 2 Gttornegs Patented Nov. 8, 1938 UNITED vSTATES PATENT OFFICE".A

STARTING GEAR FOR INTERNAL COMBUS- TION ENGINES Application July 6, 1936, Serial No. 89,173

3 Claims.

This invention relates to air starting gears for internal combustion engines and particularly reversible four cycle engines. While not limited to utility in connection with Diesel engines the device is intended particularly for that field of use.

For practical reasons, encountered particularly in the marine field, mechanically actuated air starting valves are desired. It is important that the starting gear be set for forward or reverse running by the mere act of setting the reversing valve gear of the engine, and that the air starting gear be rendered wholly inert by the turning off of the starting air and active simply by turning on such air.

The invention meets these requirements and offers a device having other substantial practical advantages which will become apparent as the description proceeds.

In the drawings,--

Fig. 1 is a vertical section through the axis of one cylinder on a plane perpendicular to the crank shaft and showing the starting mechanism for one cylinder.

Fig. 2 is a fragmentary view similar to a p0rtion of Fig. 1 and showing a modification. In this view the parts are shown in the inactive position assumed when the starting air is turned ofi'.

Fig, 3 is a view similar to a portion of Fig. 1, showing a further modification.

A portion Vof a cylinder is shown at 6 and a portion of the cylinder head at 1. Use of the usual piston connecting rod and crank shaft is contemplated, but these parts are conventional and are not illustrated. 'Ihe cam shaft is shown at 8 and is driven as usual from the crankshaft at half crank shaft speed.

This shaft ordinarily has cams for actuating the valve gear of the engine, and it will be assumed that this Valve gear is of a type which may be set for forward or reverse running by turning the reversing shaft 9 through an angle of 180. As many valve gears which could be arranged for this purpose are known (including that shown in my Patent No. 2,090,735, granted August 24, 1937) and as the present invention involves the air starting valves and is not affected by the engine valve gear, it is deemed unnecessary to illustrate the reversing valve gear of the engine. The cam I I on shaft 8*' is the air starting cam and is fast on the shaft.

Inserted through head 1 is the housing I2 which seats on shoulder I3 and is held to its seat by yoke I4 drawn down by nuts I5 on studs I6. Only one of the plurality of studs actually used is visible in the drawings. At the lower end of housing I2 is a seat for the poppet type air inlet valve I1 which has guide wings I8' on its stem to center it in housing I2.

'I'he upper end of the valve stem is shouldere at I9 and is fixed in a sleeve 22 by a nut 2| threaded on its end. Sleeve 22 makes a close sliding t in the upper end ofV housing I2r and carries at its upper end a cup-like cylinder 23 in which works a cup-shaped piston 24'. A vented cap 25 limits the upward motion of piston 24 andv acts as a seat for spring 26 which urges the piston downward. A link 21, acts inthrust with piston 24 and its lower headed end is retained by clip 28'. Spring 20 urges valve I1 closed.

The upper end of link 21 is pinned at 29 to rock lever 3| pivoted at 32. The other end of lever 3l is pinned at 33 to push rod 34, whose lower end is guided by a swinging link 35 pinned thereto at 36 and fulcrumed at 31 to a crank arm on reversing shaft 9.

At its lower end push rod 34 carries a roller 3B which is confined in the angular slot 39v on rocker 4I'. two cam followers to coact with cam II, one for forward and the other for reverse running.

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Rocker 4I is fulcrurned at 42 and has These followers take the form of rollers 43 rand 44. Roller 43 is conditioned to become effective when roller 38 is in the innerend of slot 39 (i. e., the end toward cylinder 6, as shown in Fig. 1) and roller 44 is conditioned to become effective when shaft 9 is turned 180 from the position shown in which case roller 38 is in the outer end of slot 39. Neither roller is, however, actually effective to coact with cam I'I unless the starting air is turned onr 'I'he starting air bottle or other source of starting air under pressure is indicated at 45 and supplies air to a three-way valve 46, which in the starting position shown in Fig. l connects. source 45 with passagel 41. In runningvposition valve 46 interrupts this connection and vents passage 41 to atmosphere. 48 to valve I1 and by passage 49 in the stem of valve I1 communicates with cylinder 23 beneath piston 24.

Consequently, when starting air is turned on, piston 24 is forced up overpowering spring 26, andv increasing the distance between valve I1 and pivot 29. With shaft 9 in the position shown this tilts rocker 4I so that roller 43 coacts with cam II. With shaft 9 turned 180 from the position shown roller 44 would coact with cam II upon the admission of starting air. When cylinder 23 is vented, as it is in running position yof valve 46, the rocker 4I is held in an intermediate Passage 41 leads through port the cylinder controls the exhaust of startingairk from the cylinder.

, By confining the rollerrrlllfin slot 39 piston 424 controls rocker'4l. As shown in Fig. 2 aspring 5| can be used to bias the rocker to its inert position in which both 'rollers' clear the cam.- In this figure parts similar to those in Fig: 1 are similarly numbered with the letter a. The slot 39 becomes an angular thrustsurface 39o/with'4 which roller 38a acts in unidirectional thrust.

The operation is essentially similar to" that al' ready described. Y 4 f y.

In Fig. 3 a further modification -is shown. Instead of changing the-eiectiveflength of the link 21 which connects valve lrlnwith rocker 3|, as in Fig. v1, the axisYK of the fulcrum for rocker 3| is shifted with similar effect. This Yarrange.- ment, unlike that shown in Fig..v1, requires only one air motor to shift therockersvfor a plurality of cylinders because with alined cylinders all the fulcra can be shifted asa unit. Y A,

In Fig. 3 the parts corresponding` to: those numbered to 2| and-34 to 48 of Fig, 1,are unchanged. Suchof these parts as `are visible in Fig. 3 are numbered as in Fig. 1v but with theV letter b. The parts 34a, to 44a of Fig. 2 can be substituted as before. Y 1 Y j Nut 2lb and shoulder ISbaiTord a rigid con;- nection between valveY IIb and, sleeve 22h, the sleeve being guided inohousing |2b. A spring2llb urges valve Ilb closed. 1 Y

A link 2lb pinned to sleeve 22h is pinnedv at 29bjto rock lever 3|b, whose otherv end is;Y pinned at'33b to push rod 34h. Rod 34h is functionally identical with rod 34 Fig. 2.Y A

Rocker 3|b is Ymounted `on the journal 32h, which is eccentrically mounted on shaft-50 c arried in the bearing pedestals 59; AnA arm 52 fast on shaft 50 is connected bylink53 with piston 54, the piston workingin cylinder 55.,A spring 56urges piston 54 downward. vA vented cap 51 limits upward rmovement' of vthe piston and the lower end of the cylinder limits its downward movement. Cylinder 55 is mounted on head 1b' and' a branch 58 of port 4'lb communicates'with its lower end. a

The normal position of piston 54 is at the lower end of cylinder.55. `Journal32b is then in its raised position and the cam follower shifts to inactive position. When starting air is turned-on the piston 54 moves up to the position of Fig.A 3, llowering journal 32h and rendering the cam follower active (see position indicated in Fig. l) In a multi-cylinder engine only one piston 54 and cylinder 55 needl be used, since a single shaft 50 can carry journals 32h, one for each cylinder. C

of Fig. Vl and rod34a. of

Other modifications Within the scope of the invention are possible and are contemplated.

What is claimed is,-

1. The combination of an internal combustion engine, including a working space, a cam shaft, and a reversing member shiftable between forward and reverse settings; a starting cam on said shaft; a rocker havingtwo cam followers, one for each direction of starting, said followers being brought selectively into coactive relation with said cam by reverse tilting of said rocker;

a-normally closed valve for admitting starting air to said working space; driving connections between said rocker and said valve, said connections being displace'able between two positions,

in which respectively they are conditioned to tilt the rocker reversely; connections through which the reversing member according to its setting, sets said driving connections selectively in said two positions; a shiftable element associated with said driving connections and having anormal position inrwhich. said connections irrespective of their position, set said rocker in Van. intermediate inactiveposition, and a starting position in vwhich said connections tilt said rocker in one'or the other direction as determined by thev position ofthe reversing member; means biasing said element to said normal position; a

motor for shifting said element to the second position; and means arranged to supply air to alternatively to cut off said lsupply 4and deenergize said motor.

2. The combination of an internal combustion engine, including arworking space, a cam shaft,

.-3,0 said starting valve and energize saidinotor, and

and a reversing` member shiftable between for- Ward and reverse settings, a starting cam on said shaft; a rocker having two cam followers, one for each direction of starting, said followers beingbrought selectively into coactive relation with said cam by reverse tilting of said rocker; a normally closed valve for admitting starting air to said working space; driving connections between said rocker and said valve, said 4connections being displaceable between two positions, in which respectively they are Yconditioned to tilt the rocker reversely; connections through which the reversing member. according to its setting, sets said driving connections selectively in said two positions; a shiftable element associated with said driving connections and having a normal position in which said connections irrespectiveof their position, set said rocker in an intermediate inactive position, and a starting position in which said connections tilt said rocker in one or the other direction as determined by the position of the reversing member; means biasing said element to said normal position; an air ymotor for shifting said element to the second

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