US2275921A - Reversing gears for diesel engines - Google Patents

Description

March' I, 1942.

G.' E. RAMsTAD v REVIEIRSING` GEARS FOR DIESEL ENGINES Filed Aug. 1, 1940 4 Sheets-Sheet l .Marh10,1942. l GERAMSTADL 2,2??921v REVERSING GEARS FOR DIESELvENGNES Filed-Aug. 1, 1940" l' v4 Sheng-sheet 2 -IIII- 5 Y n '"n" l um! f AHEAD um l NORMAL, LEAD v 44;

95 96 lol NORMAL SPEED attorneys March 1o, 1942. E, RAMS'TAD A'2,275,921

REvERsING GEARs FOR DIESEL. VENGINEs Filed'Aug. 1, 1940 sheets-sheet 3 nun 3 March 1o, 1942.

G. E. RAMsTAD REVERSIG GEARS FOR DIESEL ENGINES FiledAug. 1', 1940 v sheets-snaai 4` AHEAD Cfttornegs Patented Mar. l0, 1942 Y nEvEaslNG GEAns Foa DIESEL ENGmEs George E. Ramstad, Milwaukee, Wis., assignor to Nordberg Manufacturing Company, Mii

waukee,

Wis.. a corporation of Wisconsin Application August 1, 1940, Serial No. 349,271

1,1 Claims. (Cl. 123-41) This invention relates to reversing gears for Diesel engines, and particularly to the reversal and control of fuel injection in two cycle engines of the mechanical injection type.

In a pending application, Serial No. 258,777, filed February 27, 1939, issued June 3, 1941, as Patent Number 2,243,883 I describe a reversing gear for reversing not only the fuel pump mechanism, inlet and exhaust valves of a four cycle Diesel engine, but also for reversing the air starting mechanism. The whole mechanism is so interrelated, and is provided with such interlocks, that a single controller is movable from the neutral or stop position in two opposite directions for reverse directions of operation. There is thus a forward range of motion and a reverse range of motion of the controller. Each of these ranges is subdivided into three subranges. Counted in order from the stop position, each first sub-range is one in which the reversing movement for4 the various valve gears takes place, the second is an air starting range in which the engine is put into motion by compressed air, and the third is a fuel control range within which the starting air is cut oif'and the fuel feed is controlled, the feed increasing with displacement of the controller from neutral or stop position.

The present invention has to do with fuel injection only, and though the device is suited for use as the fuel injecting mechanism in the general control combination above defined, the novel features have to do solely with fuel control, and, hence, will be discussed on that basis. The invention permits use of the gear of my prior application with two cycle mechanical injection engines.

I have determined that with a two cycle mechanical injection Diesel engine, the time of injection should be varied in relation to engine speed, for very much the same reasons that the time of ignition is varied in relation to engine speed in internal combustion engines operating on the Otto cycle.

The present invention produces a simple means for displacing the fuel cam shaft of a two cycle Diesel engine, angularly with respect to its drive,

so that a single set of fuel cams may be set alternatively for forward and for reverse running.'

This primary adjustment is effected by means of a rack which engages a gear associated with the cam shaft drive. A reversing motor moves this rack full stroke between a vforward running position and a reverse running position. In order to modify the lead or timing of the fuel injection,

the parts are so formed that the gear is displaceable in the direction of its axis and transversely of the rack, and such displacement causes angular displacement of the cam shaft. In the preferred arrangement, the rack is provided with teeth which are oblique with reference to the rack, and the gear is mounted on straight splines so that it may be shifted transversely relatively to the rack. Such shifting, because of the lobliquity of the teeth, rotates the gearand hence .the shaft, in proportion to the lateral displacement .of the gear. Various alternative schemes will suggest themselves.

Movement of the rack between forward and reverse position entails movement of a secondary member which is connected through a variable stroke linkage with the gear displacing means in such a way that the motion of the secondary member moves the aforesaid gear laterally, more or less, depending on the'adjustment of the linkage. The adjustment of the linkage might be effected manually, but for best results it is effected by a servo-motor under the control of a governor v responsive to engine speed.4 It is not necessary or even desirable that suchservo-motor develop force suflicient to shift the linkage while the cams are 'actuating the fuel pump. By limiting the force developed by the servo-motor, the adjustment may be caused to be intermittent, occurring when the cam shaft is lightly loaded. This reduces wear. In this discussion, the term lead is used to define the crank angle between the start of injection and the dead point. l

Thus, the reversal of the engine is characterized by two concurrent adjustments ofthe angular position of the cam shaft relatively to the crank shaft. The first or basic adjustment is of considerable range and establishes the funda- Vthe desired variation of lead from normal speed to low speed is 4 in each position of running. From this it follows that the maximum angular rangeA of adjustment from minimum lead running forward to minimum lead running reverse is 108. On this basis, the primary adjustment could be'zset to give an angle of adjustment of 108, and the secondary adjustment could subtract from this 4 in each range from mid-position, in which case the setting for maximum or normal lead would involve a shift of only 100.

I prefer, however, and illustrate for purposes of disclosure, an arrangement in which the primary adjustment displaces the crank shaft through an angle of 100, and the lead varying adjustment lproduced by axial displacement of the gear adds 4 for minimum lead conditions to each direction of running, so that the extreme range of angular adjustment is108.

Because the two 'schemes are approximately equivalent and involve merely reversals of pitch, it is deemed necessary to illustrate only the preferred arrangement, in which the compensatory or lead adjustment is additive rather than subtractive.

While the lead adjustment could be made manually, the invention gives its greatest utility when the lead adjustment is made in response to engine speed by a governor. An important aspect is that the control of lead by the governor is precisely the same for both directions of running; i. e. the reversing gear introduces no disturbing factor as to the governor control. The particular form of the governor is not a feature of the invention and will not be developed in detail. It is desirable to use that type of govemor in which the speed responsive device pilots -a servo-motor and the motor develops the force necessary to shift the lead controlling linkage.

Again referring to a commercial embodiment of the invention, it has been found satisfactory so to arrange the governor that it sets the mechanism for normal lead at normal engine speed, and reduces the lead progressively to the minimum value at an engine speed of approximately 112 R. P. M. Below this speed, the minimum lead setting remains in effect, because a change of lead below this speed has rio practical significance.

The invention will now` be described with reference to the accompanying drawings, which are limited to the mechanism for changing the timing of fuel injection, omitting all air starting gear but showing means for varying the quantity of fuel injected. It should be understood, however, that mechanisms for accomplishing these purposes are well known and that the invention introduces no limitation on their use. In fact, it is contemplated that the invention will be incorporated in a complete reversing gear including mechanisms of the type mentioned.

In the drawings:

Figure 1 is a vertical section transverse to the crank shaft of a mechanical injection Diesel engine, taken on the axis of one of the cylinders of the engine and through the fuel pump which delivers fuel to that cylinder. The engine is shown set to run forward, and forward directions of motion of the various components are indicated by arrows. The reverse position of the cam for that cylinder is indicated in` dotted lines.

Fig. 2 is a vertical axial section through the reversing motor and rack,-with the lock mechanism, parts being shown in the up or forward running position, and a portion of the rack being broken away to reduce the length of the figure. y

Fig. 3 is a horizontal section on the axis of the cam shaft, drawn on a larger scale than Fig. 1,

sition and with the secondary adjustment zero, so that there is maximum or normal lead.

Fig. 4 is a view similar to Fig. 3, showing ahead position with the minimum lead setting and showing. also, the planetary drive for the cam shaft and the cam shaft with the cam in the ahead position of Fig. l.

Nora-With reference to Figs. 3 and 4, it should be observed that the right-hand end of each of these figures is toward the observer in Fig. 1.

Fig. 5 is a detail view of the axially .shiftable gear. f

Fig. 6 is a detail view of the back of the reversing rack.

Fig. 'l is a section on the line 1-1 of Fig. 4. Fig. 8 is a section on the line 0 8 of Fig. 4; and

Fig. 9 is a section on the line 9-9 of Fig. '7.

Referring first to Fig. l, |I represents the crank case and I2 represents the jacketed cylinder of a Diesel engine. Only one cylinder is shown, but normally the engine would have a plurality of cylinders connected to a common crank shaft with fuel injection pumps operated by cams on a single cam shaft, hereinafter described.

The piston I3 is connected byf the connecting rod Il to a corresponding crank I5 on the main crank shaft I6. The cam shaft I1 turnsat crank shaft speed, as will hereinafter be described, and is provided with fuel cams I3, one for each cylinder. 'I'he forward setting of the cam shaft is indicated in full lines in Fig. 1, and the reverse position of the cam for the illustrated crank angle is indicated in dotted lines.

A roller cam follower I3 coacts with the cam to 'reciprocate the fuel plunger 2| of a variable feed fuel pump of the type known in the art as a Bosch fuel pump. The plunger 2| works in a cylinder 22 and may be rotated about its longitudinal axis by a sleeve 23 which is splined to the plungerv and which is rotated by the displacement offa rack 24. The end of the plunger has a spill-back port indicated generally at 25, so that the angular position to which the plunger is turned determines the amount of fuel delivered per stroke. The variable spill-back occurs at the end of fuel delivery, so that the start of delivery is timed by the cam and the duration of delivery is controlledv by such angular position of plunger 2|. The fuel oil is delivered through a check valve 28 and pipe 21 to a fuel injection nozzle 28 of known form. 'I'he present invention is concerned merely with the timing of reciprocation of the plunger 2|.

The crank shaft I6 carries a pinion 3| and this drives a large gear 32 which is not fast on the shaft I1 but, on the contrary, is a ring gear on a cage 33 which rotates coaxially with the cam shaft I1. The cage 33 is the housing of a planetary transmission which is coaxial not only with the cam shaft I1, but with an axially aligned timing.control shaft 3l. The cage 33 carries a series of .beveled planet pinions 35 which mesh with a beveled sun gear 38 fast on the control shaft 34 and with a driving gear 31 fast on the cam shaft I1. 'I'he ring gear 32 has twice the pitch diameter of the crank shaft ,pinion 3| and,

consequently, the angular velocity of the cage 33 is half the angular velocity of the crank shaft, but since the sun gear 36 is at rest, except for the reversing adjustments hereinafter described, the driving gear 31 and the cam shaft I1 rotate and showing the reversing gear set in ahead po- A at twice the angular velocity of the cage 33.

pherlc port 51.

Consequently, the cam shaft turns at crank shaft speed, but in the opposite direction.

Remembering that reversal is to be effected by displacing the cam shaft I1 angularly with reference to the crank shaft I6, it will be apparent that for any desired angular adjustment of the shaft |1, an equal and opposite angular adjustment of the shaft 34 must be made.

The shaft 34 having been related to the components of the engine which are affected thereby, the discussion from now on will refer primarily to the control shaft 34. lIt may be remarked that'no effort has been made-to illustrate the bearings which support the cam shaft l1 or the crank shaft, because these features are conventional and do not enter into the invention.

As in my prior application, above identified, reversal is produced by admitting air to opposite ends of a pneumatic piston motor, the air supply being cut oi and the motor vented as soon as it has completed its working stroke.

The air motor is shown in detail in Fig. 2. In this figure 4| represents the air cylinder and 42 represents a motion controlling check cylinder that is separated therefrom by an interposed cylinder head 43. A piston 44 in the cylinder 4| is connected .by a rod 45 with a' check piston 45 in the cylinder 42. The lower end of the rod 45 extends beyond the cylinder 42 and is connected to a rack 41. The two Working spaces in the cylinder 42 are connected by a pipe 48 with adjustable throttling needlevalve 49. The working spaces are kept charged with oil under pressure by a branch pipe which leads from a portion of the force feed lubricating system of the engine, a check valve52 being interposed. The piston 46, therefore, merely prevents unduly rapid reversing motion.

To move the piston 44 and, consequently, the rack 41 to forward setting, which is the one shown in Fig. 2, air is admitted to the lpipe 53 until the shift is completed and then -pipe 53 is vented. For reverse shifting, air is admitted to the pipe 54 until the shift is completed, and then the pipe 54 is Vented. The admission and venting functions are controlled by a maneuvering gear functionally similar to that forming the subject matter of my prior application, and not hereinvolved.

Some means to latch the rack 41 in its two extreme positions are necessary and are embodied in a latching motor enclosed in the housing 55. Housing 55 takes the form of a diierential or shouldered cylinder in which works a combined latch piston and valve 56, also shouldered as shown. A coll compression spring 51 urges the piston to the right, so that a latch nose 58 will engage beneath a latch shoulder 53 on the back of the rack 41 when the rack is in its upward or ahead position, and will engage behind a companion shoulder 5| when the rack is in its reverse position.

Leading from the housing 55 at the side opposite the connections 53 and 54, and slightly offset axially therefrom, are two pipe connections. The first, 63, leads to the lower end of the cylinder 4|, and the second, 64, leads to the upper -end of the same cylinder. In the latching position of the piston 55, these connections communicate with exhaust ports 55 and 55 in the. piston 56, so that `both working spaces in cylinder 4| are then vented to atmosphere by way of atmos- When air under pressure is admitted to the pipe 53, the piston 55 moves outward so that the 75 exhaust ports 65 and 66 move out of register. At such time, the outward movement of the piston connects pipe-53 with pipe 63, and pipe 54 with pipe 54. Consequentlythe piston 44 is -moved upward full stroke, the space above the piston 44 being exhausted through the pipe 54.

When pressurefluid is admitted to the pipe 54, the reverse or downward motion takes place. At the end of thetraverse and-upon venting of the pipe 53 or 54, whichever was under pressure, the latch reengages. s

The apparatus shown in Fig. 2 is simplya full stroke vreversing motor with a `uid pressure latch which engages to hold the rack at the limit of motion vafter `it has arrived at such limit. Various mechanisms of this type are known and equivalents may be substituted. In fact, any full stroke motor which will remain in its full stroke position at both limits of traverse could be used. The sole object is to move the rack full stroke between two limiting positions and retain it in the nal limiting position. The upward position is the ahead setting-of the reversing gear, and the lower position is the reverse setting.

In Fig. 6. the back of the rack is illustrated. The latch shoulder 59 is shown. The cam slot 68 which coacts with a follower 69,'shown in Figs. A

3 and 4, is a part of the interlock of my prior application, which assures that the reversing motor moves full stroke before the reversing air is cut olf. The cam slot 68 and follower 69 are not a part of the present invention and are here illu:- trated merely to indicate the possibility of interconnection with the maneuvering mechanism of my prior application. No claim to such mechanism is made in the present application.

The rack 41,1as best shown in Fig. 8, has Qblique teeth, and meshes with a spirally toothed gear 1| which is mounted on straight splines 10 on the shaft 34. It is simpler to form the rack with inclined teeth and the gear 1| with spiral teeth than it would be .to make the splines 10 spiral. Hence, the construction illustrated is adopted, but the basic idea underlying the mechanism is that axial displacement of thegear 1| across the face of the rack 41 shall entail limited terbored to receive an axially shiftable plunger 16 which is held in place by the screw plugs 11 which are threadedyinto the gear 1|v (see Fig. 9). The cross-pin 16 is flat in cross section, as best kshown in Figs. 5, 8 and 9, and the threaded counterbores for the plugs 11 occur in inactive areas of the gear 1| fromwhich the teeth'are omitted. The maximum angle of motion of the gear'll is of the order of 108, so that the'omission of a portion of the teeth at diametrically opposite points is practicable.

The counterbored portion voflongitudinally slotted as indicated at 18 to yafford clearance for the pin, but the torsional reaction the shaft y34 is between the gear and the shait is taken up by the splines 10 and not by the pin 16. Similarly, as best shown in Fig. 7, the plunger 1.2 is arcuately slotted as indicated at 19, to permit free angular motion of the pin 18. Thus, the only duty imposed on the pin is to shift the gear 1| in the direction of the axis of the shaft 34.

The outer end of the plunger 12 is slotted or bifurcated so that it affords two parallel lugs or extensions 8|. These are each pinned on aligned axes 82 to one end of a corresponding one of a pair of longitudinally channeled spaced links 88. The other ends of these links are pinned on aligned axes 84 to a bifurcated yoke 85. The construction is such that the two links 83 are parallel at all times, swinging in unison so that they are, in effect, a single link. However, for ease of assembly, it is convenientto use two distinct links so connected that they move as one.

Each link has a longitudinal channel-like guideway 86 in which is slidable a fulcrum block 81. The two fulcrum blocks are pivoted on concentric axes 88 to a slider 89 which is guided in ways 9| to move at right angles to the axis of the shaft 34. At the inner limit ofmotion, the pivots 88 are coaxial with the pivots 82, and under this condition, regardless of the position of the pivots 84, the gear 1| is in its mid-position (see Fig. 3).

The slider 89 is connected by a link 92 with the controlling element f a governor mechanism 93 which is responsive to engine speed. So

' far as is material to the present invention, the

governor mechanism is such that when the engine speed is normal, the parts assume the position shown in Fig. 3, in which the pivots 88 align with the pivots 82. As engine speed is reduced from normal, the slider 89 is shifted progressive ly to the position shown in Fig. 4, which is the low speed position. This position is assumed at a chosen minimum engine speed and all speeds below that minimum. In one engine constructed according to the invention, this minimum speed was of the order of 112 R. P. M. but the minimum is a matter of choice. Because the load on this governor is substantial, the governor should be of that known type in which the member 92 is shifted by a servo-motor in response to the indi.

cation of a. speed responsive device. Since such governors are well known in the art, detailed illustration is not necessary.

The yoke 85 is pivoted at 94 to some part which moves a definite distance in a path parallel with the axis of shaft 34 during the full traverse of the rack 41. In the preferred embodiment, the pivot 94 is carried by a threaded member which is traversed in a direction parallel with the axis of the shaft 34 by a nut which rotates through adenite angle as the result of the displacement of the rack 41 through its full traverse.

Thus, the threaded member is shown at 95 and is provided with multiple right hand quick pitch threads, 4as clearly shown atl96. 'I'he nut 91 has companion internal threads 98 and is mounted to turn in bearings 99 formed in a part of the housing mechanism. The nut is provided with spiral teeth |0| which mesh with the spiral teeth on the gear 1|, it being understood that the axis of the nut 91 is parallel with the axis of the shaft 34. It will require only a moments reflection to appreciate that while the nut 91 is turned by the motion of the rack 41, it is unaffected by axial displacement of the gear -1|, for the pitch of the spiral threads is such that the gear 1| may be displaced axially while the nutl 91 and the rack 41 both remain at rest.

Operation v The operation of the device in motion from the .position shown in the drawings, which is forward running position. to reverse running position will now be traced.-

To bring about this action air is admitted to the pipe 54 until the piston 44 moves downward its full traverse. The first effect is to disengage vthe latch i8 and upon venting of the pipe 54,

the latch reengages. It is unnecessary to discuss the action of the interlock operated by the follower 69 and assuring full traverse before the air is cut off.

Assuming that the engine is at rest, the governor will position4 the slider 89 as shown in Fig. 4. As the rack 41 moves downward its full traverse, it will rotate the gear 1| and will also rotate the nut 91. The amount that the nut 91 rotates is directly proportional to the traverse of the rack, but the amount that. the gear 1| rotates is the combined eect of rotation by the rack and displacement of the gear 1| full stroke to the right as an incident to the displacement of the threaded member 95 full stroke to the left. This reverses the inclination of the links 83 and .forces the plunger 12 inward relatively to shaft 34. Consequently, the cam shaft |1 and cams |8 are displaced the maximum angle, here assumed to be 108. When the engine operates and as its speed rises above 112 R. P. M., the governor moves slider 89 progressively until pivots 88 and 82 align when normal speed is attained. By such motion, the gear 1| will be restored to its mid-position (Fig. 3),.establishing normal lead conditions.

Reduced to its simplest terms, the transverse of the rack imparts a denite angular rotation to the gear 1|. At the same time it displaces the pivot 84 a definite distance. The eect of the displacement of the pivot 84 is to reverse the inclination of the links 83. The governor 93 effects the lead adjustment which must be in opposite senses for opposite directions of rotation, the desired reversal of sense being produced by the reversal of inclination of the links 83. The lead adjustment is effected solely by axial displacement of the gear 1|.

While the particular arrangement shown is simple to manufacture and precise in operation, modifications within the broad scope of the invention are possible, and are contemplated.

In the rst place, various modifications of the spiral arrangement by which axial displacement of vthe gear 1I causes rotation of the shaft 34 while the rack remains at rest are obviously possible. The one illustrated is selected because it is the simplest to manufacture.

It has also been suggested that the device can be arranged for a subtractive rather than for an additive effect of the lead adjustment. This would, for example, involve reversal of the slope ofthe teeth on rack 41 and gear 1| and appropriate change of the stroke of `rack 41 on the diameter of gear 1|, to modify the extent of rotation of that gear imparted by the reversing cludlng a controlling member which when rotated changes the angular relationship between the cam shaft and the crank shaftto establish forward and reverse running conditions as to the timing'of fuel injection', and also to modify the lead of such injection; a reversing member shiftable full stroke between a4 forward running V position and a reverse running position; a driving connection between said reversing member and saidcontrolling member through which full stroke motion of the reversing'member rotates the controlling member suiciently to establish selectively said reverse running conditions, said driving connections including a displaceablev component so arranged that its displacement ro- -tates said controlling member through a lead adjusting range; a reversible motion transmitting mechanism, connected with said reversing member so as to be reversed by full stroke motion thereof, and connected with said displaceable component to actuate the same; and a lead adjusting device connected to actuate said reversible motion transmitting mechanism, and

through it to actuate said displaceable compo- `nent in relatively reverse senses in the forward the toothed actuator through a lead adjusting and reverse positions of said reversing member.

2. The combination defined in claim 1 in which the reversible motion transmitting mechanism comprises a sliding block linkage including an oblique link and a sliding block serving as a fulcrum therefor, the reversing member being connected to reverse the Obliquity of the'link and the lead adjusting device comprises a speed lilllesplcgansive governor arranged to shift the sliding oc l 3. The combination of an engine of the fuel injection type having a crank shaft, a cam shaft provided with fuel injection cams, and

A fuel injecting means operated by said cams; a

drive train .from the crank -shaft to the cam shaft including a controlling member which when rotated changes the angular relationship Vbetween the cam shaft and the crank shaft to ywhose displacement .changes the angular position of the controlling member relatively to the position of the toothed actuator througha lead adjusting range;

a member moved by said range; a member moved by said toothed actuf ator to two distinct 'positions by the-shift of the actuator between its two limiting positions; a reversible motion-transmitting mechanism arranged to be reversely set by the shift of the last named member and connected to movesaid axially displaceable components; shiftable lead controlling means arranged to actuate said axially displaceable component through said motion transmitting mechanism, the imparted motionV being reversed by reversal of the motion transmitting mechanism; and a governor responsive to engine speed for actuating said lead controlling means. n

5. The combination defined in claim 4 in which the governor is so arranged as to shift said lead controlling means progressively between full engine speed and a low limiting speed, .and to maintain said lead constant at a chosen minimum value at all speeds below said minimum speed. 1

6. The combination of .an engine of the fuel injection type having a crank shaft, a cam shaft provided with fuel injection cams, and fuel injecting means operated by said cams; a drive train from the crank shaft to the .cam shaft including a controlling member which when rotated changes the angular relationship between the cam shaft and the crank shaft to establish forward and reverse running conditions as to the timing of fuel injection; a toothed actuator shiftable full stroke between two limiting positions, one of which is'a forward andthe other a reversev setting; a gear splined to saidcon- Y trolling member and having teeth engaging the shift of the actuator between its two `limiting positions; a reversible motion-transmitting mechanism arranged to be reversely set by the shift of the last named member and connected to move said axially displaceable component: and shiftable lead controlling means arranged to actuate said axially displaceable component through said motion transmitting mechanism, the imparted motion being reversed by reversal of the motion transmitting mechanism.

4. The combination of an engine of the fuel injection type having a crank shaft, a cam shaft provided with fuel injection cams, and fuel injecting means operated by said cams; a drive train from Athe crankshaft to thecam shaft including a controlling member which when rotated changes the angular relationship between the cam shaft and the crank shaft to establish teeth of said toothed actuator', the forms of theV teeth and of the spline being so correlated that vaxial displacement. of the gear in opposite directions from normal midposition produces rotary adjustment of the, controlling member through opposite lead adjusting ranges; a member moved by the shift of saidtoothed actuatorto two distinct positions; a reversible motion transmitting device reversely set by shift of the last named member and connected to move said gear axially; and lead controlling means shiftable to` impart motion to said motion transmitting device, the imparted motion being reversed by reversal of the 'motion transmitting device.

'7. The combinationdened in claim 6 in which the toothed actuator has oblique teeth and the splined gear which meshes therewith has spiral teeth.

8. The combination defined in claim 6 in which the member moved by the shift of the toothed actuator to two distinct positions is a second gear meshing with said splined gear.

- 9. The combination of an engine of thefuel j injection type having a crank shaft, a cam shaft provided with fuel-injection cams, and fuel injecting means operated by said cams; a drive of which is driven by the crank shaft, and a third element of which is relatively fixed, but rotatable to change the angular relationship between the cam shaft andthe crank shaft, both to establish forward and reverse running conditions as to the timing of fuel injection and to modify the lead of fuel injection; a toothed actuator shiftable full stroke between two limiting positions, one of which is a forward and the other a reverse setting; a gear splined to said third element of the planetary train and having teeth engaging` the teeth of said toothed actuator, the forms oi' the teeth and of the spline being so correlated that axial displacement of the gear in opposite directions produces lead modifying angular adjustment of the third element of the planetary train; a member operlatively connected with said toothed actuator to 10. The combination defined in claim 9 in,

which the reversible motion transmitting device comprises an oblique link and a coacting sliding block, the member shifted by the toothed actuator serving in its two positions to establish relatively reverse oblique settings of the link, and the means for actuating the lead controlling means is connected to shift the block.

11. The combination of an engine of the fuel injection type having a crank shaft, a cam shaft provided with fuel injection cams and fuel injecting means operated by said cams; a drive train from the crank sli-aft to the cam shaft including a controlling member which when rotated changes the angular relationship between the cam shaft and the crank shaft to establish forward and reverse running conditions as to the timing of fuel injection, and also to modify the lead of such injection; a reversing motor shiftable full stroke between a forward running position and a reverse running position; two individually operable driving connections between said reversing motor and said controlling member. one of said connections being a direct connectionthrough which the reversing motor turns said controlling member through a range suilcient to effect reversal of timing relation and the other being a motion reversing connection comprising a shiftable fulcrum.member, a link fulcrumed thereon and connected to transmit motion to said controlling member and means whereby the reversing motor reverses the Obliquity of the link relatively to the 4direction of shift of the fulcrum member; and lead controlling means for shifting said fulcrum member.

- GEORGE E. RAMSTAD.V

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