US2212140A

US2212140A - Chronometric mechanism

Info

Publication number: US2212140A
Application number: US126398A
Authority: US
Inventors: Ferris Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-02-18
Filing date: 1937-02-18
Publication date: 1940-08-20
Anticipated expiration: 1957-08-20

Description

Aug. 20, 1940. w. FERRIS 2,212,140

CHRONOMETRIC MECHANISM Filed Feb. 18, 1937 ll Sheets-Sheet 1 F Fig.1. 5 4

INVENTOR VVALTER FEFeFeIS ATTORNEY Aug. 20, 1940.

w. FERRIS 2,212,140

CHRONOMETRI C MECHANISM Filed Feb. 18, 193' Fig.5.

ll Sheets-Sheet 3 INVENTOR MEI-ER FEHFHS ATTORNEY Aug. 20, 1940. w. FERRIS 2,212,140

CHRONOMETRIC MECHANISM Filed Feb. 18, 193' ll Sheets-Sheet 4 v9 2N? v V V \vmxw INVE TOR 55 VVALTEH ERFQIS WTORNEY Aug. 20, 1940. w. FERRIS 2,212,140

CHRONOMETRIC MECHANISM Filed Feb. 18, 1937 ll Sheets-Sheet 5 5] INVENTOR WALT EFF FEFERIS BY m ATTORN EY Aug. 20, 1940. w. FERRIS CHRONOMETRIC MECHANISM Filed Feb. 18, 193' ll Sheets-Sheet 7 J INVENTOR 55 WALTER FERRiS BY 2 E ATTORNEY Aug. 20, 1940. w; FERRIS 2,212,140

CHRONOMETRIC MECHANISM Filed Feb. 18, 193' ll Sheets-$heet 8 INVENTOR ALTER FERHIS BY Aug. 20, 1940.

w. FERRIS 2,212,140

CHRONOMETRIC MECHANISM Filed Feb. 18, 193

ll Sheets-Sheet 9 INVENTCR WALT ER FERRIS wkmw ATTORNEY Aug. 20, 1940- w. FERRIS CHRONOMETRIC MECHANISM Filed Feb. 18, 193 ll Sheets-Sheet 10 Fig.1 C].

IIL

INVENTOR VVALTEFe F ERF? IS ATTORNEY Aug. 20, 1940. V w FERRIS 2,212,140

CHRONOMETRI C MECHANISM Filed Feb. 18, 193 ll Sheets-Sheet ll INVENTOR VVALTER F ERFHS TTORNEY Patented Aug. 20, 1940- UNITED STATES PAranr orrica 18 Claims.

This invention relates to apparatus for controlling the speeds of prime movers such as the apparatus disclosed in Patent No. 2,198,035 which issued on application Serial No. 47,008, filed October 28th, 1935, of which this application is a continuation in part.

The function of the apparatus disclosed in the above patent is to maintain the speed of a prime mover proportional to a standard or measuring speed, such as the speed of a chronometric mechanism, a constant speed electric motor ora moving body.

The primary object of the present invention is to provide a chronometric speed controller by means of which the speed of a prime mover. may either be maintained constant or be varied according to a predetermined schedule.

More specific objects and particular advantages of the invention will appear hereinafter.

The invention is exemplified by the chronometric controller shown Lin the accompanying drawings in which the views are as follows:

Fig. 1 is a top plan view-of the controller mechanism with certain parts shown in section or partly'broken away to expose other parts, the view being taken through the upper part of the controller casing as indicated by the line i--'l of Fig. 2.

Fig. 2 is a front view of the controller mecha nism as indicated by the line 22 of Fig. 1.

Fig. 3 is a vertical section taken on the line 33 of Fig. 1.

Fig. 4 is an elevation of the right side of the controller mechanism as indicated by the line 4 -4 of Fig. 1.

Fig. 5 is a vertical section taken on the line 5-5 of Figs. 1 and 2.

Fig. 6 is a rear view of the controller mechanism as indicated by the line 6-15 of Fig. l, certain parts being broken away and other parts being shown in section.

Fig. 7 is an elevation of the left side of the controller mechanism as indicated by the irregular line 'l'! of Fig. 1%

Fig. 8 is a sectional plan view of a difierential gear and associated parts, the view being taken in the plane of line of Fig. 3.

F g. 9 is a sectional 99 of Fig. 2.

Fig. 10 is a transverse section taken on the line llllll of Fig. 1 but showing certain gears out of mesh with each other.

Fig. 12 is a bottom sectional plan view showing plan view taken on the line the control valve on a larger scale, the view being taken on the line 12-52 of Fig. 7.

Fig. 13 is a view showing a part of the escapement mechanism on a larger scale.

Fig. 14 is a sectional plan view taken on the 5 line 16-!4 of Fig. 13.

Fig. 15 is aschematic drawing showing the controller employed to control the speed of a hydraulic motor. I

Fig. 16 is a view showing another method of operating the control valve.

For the purpose of illustration, the invention has been shown in Fig. 15 as being employed to control the speed of a hydraulic motor l which drives variable load 2, but it is to be understood 15 that the invention may as readily be employed to control the speed of any other type of prime mover as explained in the patent referred to above.

Motor i is energized by motive liquid supplied 9 thereto by a pump 3 which is connected to motor i by a supply channel t and a return channel 5 and which has its displacement varied by the controller in response to any variation in the speed of motor l relative to a standard or meas= uring speed as will be presently explained.

Pump 3 may be of any suitable type. The pump shown schematically in Fig. 15 has not been illustrated nor described in detail as it is fully illustrated and described in Patent No. 2,074,068. It is deemed sufilcient to state that it has its pistons b fitted in cylinders formed in a rotatable cylinder barrel 1 which is jonrnaled upon a central valve shaft or pintle 9 through which liquid flows to and from the cylinders, that cylinder barrel l is rotated at a substantially constant speed by a prime mover not shown, that pistons 6 react against an annular reaction surface 9 which is carried by a slide block iii and which is eccentric to cylinder barrel i when the Pump is delivering liquid, and that slide blocl: i0 is shiftable transversely of pintle e to vary Dump displacement and consequently vary the rate at which pump 3 delivers liquid to motor i.

As shown, slide block it is urged in a direction to decrease pump displacement by a piston ll fitted in a cylinder 12, and it is adapted to be moved in a direction to increase pump displace ment by a wedge or cam it having its inclined or cam face in engagement with a roller it car= 5o ried by slide block it and its opposite face in engagement with a roller it carried by a stationary abutment l6.

Cam i 3 has one of its ends connected to a piston H which is fitted in a stationary cylinder 16. 55

The other end of cam I3 is connected to a piston I9 which is fitted in a stationary cylinder 23. Liquid for operating pistons II, I! and I9 is supplied by a gear pump 2I which is ordinarily driven in unison with pump 3 and arranged in the casing thereof as shown in the above patent.

Gear pump 2i draws liquid from a reservoir 22 and discharges it into a branched supply channel 23 at a rate in excess of the rate at which gear pump liquid is utilized. The liquid discharged by gear pump M in excess of requirements is exhausted through a relief valve 23 which enables gear pump ii to maintain in channel 23 a constant pressure equal to the resistance of valve 23.

In order that gear pump 2! may also supply liquid to pump 3 to make up for leakage losses according to the usual practice, channel 23 may be connected direct to channel 5 or, if it is desired to supercharge pump 3 ate. pressure lower than the pressure employed for operatingservomotors II-IZ and I9-23, channel 23 may be connected to channel 5 through a low pressure resistance valve 25 as shown.

Channel 23 has one of its branches connected to cylinder I2 and another branch connected to cylinder 23 so that piston II exerts a constant force upon slide block I3 and tends to move it in a direction to decrease pump displacement, and piston I9 exerts a constant force upon cam I3 and tends to move it downward or in a direction to Epermit piston IE to move slide block I0 toward zero displacement position.

Liquid for operating piston H to move cam I3 upward is supplied by gear pump 2i to cylinder I8 under the control of a valve 33 having three spaced, apart heads or pistons 3!, 32 and 33 formed thereon and closely fitted in the bore 33 of a valve casing 35 which has an annular groove or port 36 formed in the wall of bore 3 and con trolled by piston 32.

A branch of supply channel 23 is connected to valve casing 33 and communicates with that part of bore 33 between pistons 3i and 32. Cylinder I8 is connected to port 33 by a channel 37. That part of bore 33 between

pistons

32 and 33 is shown as communicating with a drain channel 38 which isconnected to valve casing 35 and discharges into reservoir 22 but, in practice, a duct extends inward from the end of valve 30 into communication with the space between

pistons

32 and 33 so that liquid may be discharged therethrough into the casing which encloses the controller mechanism.

The arrangement is such that, when valve 30 is shifted toward the left from its central or neutral position, liquid may fiow from gear pump 2| through channel 23, valve casing 33 and channel 31 to cylinder I8 and raise piston ll, thereby raising cam I3 and causing it to shift slide block I0 toward the left to increase the displacement of pump 3 with a resultant increase in the speed of motor i and, when valve 30 is shifted toward the right from its central or neutral position, liquid may escape from cylinder I8 through channel 37, valve casing 35 and channel 38 into reservoir 22 and permit piston I9 to move cam I3 downward, thereby permitting piston Ii to move slide block I0 toward the right to decrease the displacement of pump 3 with a resultant decrease in the speed of motor I.

Valve piston 32 has been shown as being exactly the same width as port 36 so that the slightest movement of valve 30 toward the left .will permit liquid to flow from the gear pump to servemotor III8 and cause it to increase pump displacement, and the slightest movement of valve 33 toward the right will open channel 31 to the drain channel and permit liquid to escape from cylinder I8 so that servo-motor IIIZ may decrease pump displacement.

However, piston 32 may be made slightly wider than port 36 and then shaded. That is, it may I have a plurality of fine tapered grooves formed around its periphery at each of its ends as shown in Fig. 12 of the above patent so that, when Valve 33 is in its central or neutral position, port 31 will communicate with both the supply channel and the drain channel and there will be a very slight flow or seepage from channel 23 to the drain.

If piston 32 is provided with grooves, a slight movement of valve 33 toward the left will increase the now of gear pump liquid into port 36 and decrease the flow therefrom so that liquid will flow through channel 31 and operate servomotor IlI8, and a slight movement of valve 30 toward the right will decrease the fiow of gear pump liquid into port 36 and increase the flow therefrom so that liquid may escape from servomotor l'iI8"and permit servo-motor III2 to decrease pump displacement.

In either case, the pressure in channel 31 is lower than the pressure in channel 23 due to the liquid being throttled as it passes between the edge of piston 32 and the edge of port 36. However, the area of piston I? is so much greater than the area of piston I3 that this low pressure liquid is able to move piston ll and cam I3 upward when valve 30 is shifted toward the left.

Provision is ordinarily made for limiting the movement of valve 30. As shown, valve 30 has a flange 39 fixed thereon to limit the valve movement in one direction by engaging the end of valve casing 35 and to limit the valve movement in the opposite direction by engaging the head of a stop screw 30 which is threaded into valve casing 35. a

Motion is imparted to valve 30 through a differential GI which has one of its legs driven at a speed exactly proportional to the speed of motor I and a second leg driven at a speed exactly proportional to a standard or desired speed as measured by the chronometric mechanism shown in Figs. 1 to 14. The third or output leg of the differential is connected through intervening mechanism to valve 30 so that any deviation of motor I from the desired speed results in movement of the third or output leg of the differential and a consequent shifting of valve 30.

Differential ll has been shown as being of the gear typebut it may be any other type, it only being necessary that rotation of one leg causes positive rotation of one or both of the other legs.

For the purpose of illustration, one leg of differential M has been shown in Fig. 15 as being driven by motor I through a drive which in-. cludes a pair of spiral gears 32 one of which is fixed upon the shaft of motor I and the other of which is fixed upon one end of a shaft 43 having a bevel gear 4 5 fixed upon the other end thereof, a bevel gear 45 which meshes with gear 44 and is fixed upon one end of a shaft 46, a bevel gear 31 which is fixed upon the other end of shaft 66 and mesheswith a bevel gear 48, and a spur gear 39 which is fixed for rotation with gear 48 and meshes with an external ring gear 50 which forms a part of one leg of differential ll. In practice, however, one leg of diiferential M is ordinarily driven from motor I through a drive of the type illustrated in Figs. 1 to 14 which show he details of the controller mechanism and to which attention is not. directed.

The controller has its mechanism arranged within a casing 55 and primarily supported by two frame members 56 and which are arranged in fixed positions within casing 55 as by being bolted to suitable bosses formed upon the bottom wall thereof. Frame members 56 and 51 are connected to each other by a plurality of shouldered bolts 58 which hold them in fixed positions in respect to each other and form therewith a rigid frame for supporting the control mechanism.

A shaft 6| (Figs. 2, 3 and 6) which is adapted to be driven by motor I in any suitable manner, is journaled in a bearing 62 carried by one side wall of casing 55. Shaft 6| has a gear 63 splined thereon and in mesh with a gear 64 which is journaled upon a stub shaft 65 fixed in the side wall of casing 55.

Gear 64 has clutch jaws 66 formed thereon and arranged in complementary sockets 6i formed in a clutch member 68 which is splined upon a shaft 69. Clutch member 68 has a flange formed thereon and overlapping gear 63 to retain it in position upon shaft 6|.

vA spring H, which is arranged around shaft 69 between a collar 12 fixed thereon and the end of clutch member 68, urges clutch member 68 against gear 64 to retain it upon shaft 65 and to retain jaws 66 in sockets 61.

Shaft 69 is connected by a universal joint 16 to a shaft 14 which is journaled' in frame members 56 and 51. When shaft 5! is driven, shaft 14 will be driven through

gears

63 and 64, clutch member 58, shaft 69 and universal joint 73.

If it is desired to change the speed of shaft "I4 relative to the speed of shaft 6!, clutch member 68 may be moved along shaft 69 against the resistance of spring ii until jaws 66 clear sockets 6'! and then swung laterally clear of

gears

63 and 64 which may then be removed and replaced by gears having a different ratio, and then clutch member 68 may be returned to its initial position.

Shaft 74 has fixed thereon two gears 78 and i9 which have the same pitch diameter. Gear 16 meshes with a gear 86 (Fig. 9) which is journaled upon a stub shaft 6i fixed in frame member 56. Gear 89 is shown as meshing with a gear 82 which is splined upon a shaft 83 (Fig. 3) and restrained from movement along shaft 83 by means of a set screw. Shaft 83 is journaled in frame members 56 and 51 and has fixed'thereon a gear 84 which meshes with the ring gear 50 of differential 4|.

The arrangement .is such that, when input shaft 6! is rotated in one direction, gear 32 may be meshed with gear 80 as shown and, when input shaft 6| is rotated in the opposite direction, gear 82 may be shifted along shaft 83 out of mesh with gear 66 and into mesh with gear 16 so that ring gear 50 will be driven in the same direction regardless of the direction in which the input shaft 6i rotates. That is, with the controller mechanism constructed as shown, ring gear 56 will always be driven counterclockwise as viewed in Fig. 5 and clockwise as viewed in Fig. 15.

Ring gear 59 is fastened by a plurality of bolts 96 to the outside of a differential case consisting of two parts 9| and 92 as best shown in Figs. 3 and 8. Bolts 90 fasten the two parts of the differential case to each other and clamp an internal ring gear 93 therebetween. Case part 9i is provided with a hub 94 which is journaled in a hearing bushing 95 arranged in frame member 56, and case part 92 is provided with a hub 96 which is journaled in a bearing bushing 9'! arranged in frame member 6? so that differential 65 is rotatably supported by

frame members

56 and 5?.

Ring gear 93 meshes with a planet pinion 9&3 journaled upon a shaft 99 which is fixed in a flange or head tilt] arranged within differential case part 9i. Flange 366 is fixed upon or formed integral with a shaft HJI which extends through hub 94 and is rotatably supported by two bearings E92 and i653 fitted, respectively, in case part 6i and in bearing bushing 95.

Pinion 98 also meshes with a sun gear tilt fixed upon a shaft m5 which extends through hub 86 and is rotatably supported by two bearings M6 and i9? fitted, respectively, in flange ill!) and bearing bushing 6?. Shaft 95 has fixed on the outer end thereof an escape wheel lflii which forms a part of a chronometric mechanism to be presently described.

When shaft )5 and sun gear i6 3 are rotating in one direction at a measured speed under the control of the chronometric mechanism and gear case 95-92 is rotating in the opposite direction at a speed which has the same ratio to the speed of shaft I65 that the pitch diameter of ring gear 93 has to the pitch diameter of sun gear M6, the axis of planet pinion 96 will remain stationary and no movement will be imparted to shaft HM.

If the speed of gear case 9i92 should increase or if the speed of sun gear B64 should decrease, planet pinion 623 would be carried around by ring gear 63 and thereby rotate shaft Elli in the direction of rotation of ring gear 93. Conversely, if the speed of difierential case 6i92 should decrease or if the speed of sun gear 164 should increase, planet pinion 66 would be carried around by sun gear 596 and thereby rotate shaft till in the direction of rotation of sun gear i636.

Motion is transmitted from shaft till to control valve til through a sleeve H2 which is journaled upon the outer part of shaft fill and restrained from axial movement thereon by a pin Hi3 which extends through sleeve H2 and is arranged within an annular groove ti l formed in the end of shaft ldl.

Sleeve H2 is caused to rotate with shaft Hit by a safety clutch mechanism consisting primarily of a notched wheel H5 fixed to or formed upon shaft E66 near the outer end thereof, and a detent H6 which is urged by a spring li'i into engagement with the teeth of wheel H5 and is arranged in a socket iii? fixed to sleeve M2 or formed integral therewith.

When shaft Hill is rotated in one direction or the other, the clutch mechanism will cause sleeve i if to rotate with it and cause valve Bil to be shifted in one direction or the other through mechanism to be presently described, thereby causing the speed of motor i to be corrected or varied. As will be presently explained, rotation of sleeve H2 in either direction is limited by a suitable stop in order to avoid derangement of certain associated mechanism. If shaft it! should continue to rotate after rotation of sleeve 5 it had been arrested by a stop. the safety clutch would yield and thereby prevent damage to the controller.

Rotation of ring gear 56 by motor 9 will cause ring gear 93, through planet pinion 68 and sun gear 666 to tend to rotate both of shafts lfil and it. However, shaft till is yieldingly restrained from rotation as by means of a weight H9 fixed in adjusted position upon an arm i283 which is fastened to sleeve H2 and extends radially outward therefrom so that, when ring gear 56 is rotated in a counterclockwise direction as viewed in Fig. 5 and thereby tends to rotate shaft IOI in the same direction, weight II 9 will yieldingly restrain shaft -IOI from rotation and enable motor I to transmit torque through the differential to shaft I05 and rotate it and escape wheel I08 in a clockwise direction as viewed in Fig. 5.

Escape wheel I08 drives a pendulum bob I25 (Figs. 3 and 4) and has its speed controlled thereby. Bob I25 is supported by two thin flexible ribbons I26 and i21 which are arranged parallel to each other and attached to bob I25 at spaced apart points so that bob I25 may oscillate freely but is restrained from movement in any other direction. Ribbon I26 extends downward from the periphery of 'a deflector sheave I28, ribbon I21 extends downward from the periphery of a winding drum I29, and the ends of both ribbons are fastened to drum I29 which may be rotated to raise and lower bob I25 and thereby vary the effective pendulum length.

By thus supporting bob I25 on parallel ribbons, the power impulses transmitted to the bob impart only translatory movements thereto without the rotation which is imparted to a bob by the rigid pendulum rod ordinarily employed in clocks. This arrangement permits the pendulum to operate accurately at very short lengths even with the large heavy bob employed in the present invention for the reason that this arrangement avoids the rotary acceleration and deceleration of the bob which would require a large part of the available energy and would seriously affect the-time of oscillation at short pendulum lengths.

The teeth of escape wheel I08 are engaged successively by two pallets I30 and I3I (Figs. 13 and 14) which are secured to or formed integral with a pallet plate I32 and extend from opposite edges thereof. Fallet plate I32 is fastened by two bolts I33 to a driving arm I34 having a circular hub I35 formed upon its upper end and journaled upon a pin I36 which is fixed in frame member 51 above escape wheel I08 as shown in Fig. 3.

The upper end of pallet plate I32 is shaped to provide a concave contact surface I31 which is complementary to the circular periphery of hub I35 and is held in contact therewith by two adjusting screws I38 which extend inward from opposite edges of arm I34 and into contact with a cylindrical stud or boss I39 fixed to or formed upon pallet plate I32. Screws I38 engage boss I39 below the center thereof and thus urge pallet plate I32 upward and hold contact surface I31 in contact with hub I35.

The holes in arm I34 for bolts I33 are slightly elongated so that, by loosening bolts I33 and then loosening one and'tightening the other of adjusting screws I38, the lower end of pallet plate I32 may be swung in one direction or the other to adjust pallets I30 and I 3| relative to the teeth of escape wheel I88, contact surface I31 sliding around upon the periphery of hub I35 so that pallet plate I32 in effect swings upon the axis of pin I36 during such adjustment A stiff rod I40 is fixed at its upper end to arm I 34 and forms therewith and with pallet plate I32 an escape lever through which power impulses are transmitted to cause pendulum bob I25 to oscillate. If the escape lever transmitted power impulses to the same contact spot in all positions of bob I25, the power impulses would vary in intensity as bob I25 was raised or lowered for the reason that the distance between that contact spot and escape wheel I08 would vary.

In order that equal power impulses may be transmitted to bob I25 in all vertical positions thereof, the lower end of rod I40 is provided with a frictionless roller I4! which is arranged at a fixed distance from escape wheel I08 and engages different points on bob I25 as bob I25 is raised or lowered. As shown, roller MI is arranged between and substantially in contact with two vertical guides I42 and I43 (Figs. 3 and 9) which are formed upon opposite sides of an opening I44 extending vertically through bob I25.

When escape wheel I08 is rotated, the teeth thereof will successively engage pallets I30 and I3I alternately and transmit power impulses through the escape lever to pendulum bob I25, thereby causing bob I25 to oscillate. The power impulses transmitted to bob I25 will be equal at all times for the reason that the distance between escape wheel I08 and the point at which the impulsesare applied to bob I25 remains constant regardless of the effective length of the pendulum.

The end or contact face on pallet I30 is inclined inward and downward, and the end or contact face on pallet I3I is inclined outward and downward as shown in Fig. 13. That is, the outer ends of the pallets are beveled or inclined in the same direction in respect to the direction in which the escape wheel rotates as indicated by the arrow.

in Fig. 13.

The arrangement is such that the chronometric mechanism is self-starting for the reason that, when power is applied to shaft I05 to rotate escape wheel I08, the tooth on the left side of escape wheel I08 in respect to Fig. 13 will act upon the beveled end of pallet I30 and force the escape lever toward the right, thereby causing rod I40 to swing bob I25 toward the right. Then, a tooth on the right side of the escape wheel will act upon the beveled end of pallet I3I and force the escape lever toward the left, thereby causing rod I40 to swing bob I25 toward the left where it is again urged toward the right by a tooth of the escape wheel engaging the beveled end of pallet I 30. The interference between either pallet and the escape wheelteeth is very small when the bob is in neutral position, so that the small moment imparted by weight II9 will be sufficient to swing the bob slightly and let a tooth of the escape wheel past the pallet.

The cumulative effect of a few of such impulses causes the pendulum bob to swing through its normal arc and then the pendulum is kept swinging by slight impulses imparted to the bob.

through the escape lever by the teeth of the escape wheel passing over the beveled ends of the pallets.

-Defiector sheave I28 and winding drum I29 (Figs. 1, 2, 3 and 4) are arranged, respectively, upon two shafts I and I5I which have the inner ends thereof supported by frame member 51 and the outer ends thereof supported by a U- sffiped sub-frame I52 bolted or otherwise secured to frame member 51. Sub-frame I52 is shown in full in Fig. 4 but has been broken away in Figs. 1, 2, 3 and 6 in order to expose other parts of the mechanism.

Winding drum I29 has a gear I53 secured thereto or formed upon its hub and in mesh with a segmental gear I 54 formed upon the upper end of a bell crank lever I55 which is pivoted upon a stub shaft I56 (Fig. 6) having one of its ends fixed in frame member 51. A roller I51, carried by a pin I51 fixed inthe lower end of lever I55,

and I21, drum I29, gears I53 and I54 and lever I55.

Cam wheel I58 (Figs. 4 and 9) is arranged upon the hub of a gear I59 fixed upon one end of a shaft I66 which is journaled in frame member 51 and in a spring container I6I arranged in frame member 56 and restrained from rotation relative thereto.

Spring container I6I (Figs. 7 and 9) has a torsional spring I62 arranged therein with its inner end fastened to shaft I66 and its outer peripheral surface in frictional contact with the inner peripheral surface of container IBI. The function of spring I62 is to assist pendulum bob I25, during downward movement thereof, to turn the gears through which cam wheel I58 is driven when raising bob I25.

The reason that the outer end of spring I62 is not fastened in a stationary position is that the operator, in raising pendulum bob I25, might cause cam wheel I59 to turn so far that roller I57 would ride over the high point thereof and permit bob I25 to descend. He might then continue rotation of cam wheel I58 with the result that spring I62 would be wound up beyond its limit and caused to break if its outer end were fastened. With the arrangement shown, spring I62 would simply slip around inside of container I6! and no damage would result. The use of spring I62 is necessary only when pendulum bob I25 is to be raised at so slow a rate that a large number of reduction gears are required between gear I59 and the motor which drives it as otherwise bob I25 would descend under its own weight and turn the gears through which it is raised.

Cam wheel I58 (Figs. 4 and 9) is clamped upon the hub of gear I59 between a spacer ring I 69 and a trip arm I64 by a disk I65 which is fastened to the end of the hub by bolts I56. By loosening bolts I66, cam wheel I58 and trip arm I55 may be adjusted relative to each other and to a cam ring I67 which is bolted to the other side of gear I59 and arranged in a recess formed in frame member 51. The function of trip arm I66 and cam ring IB'I will be presently explained.

When gear I59 is rotated, cam wheel I59 will rotate with it and cause lever I55, through the engagement of roller I 57 with the periphery of cam wheel I58, to be swung upon shaft I56 and cause gear segment I56 to rotate gear I53 and winding drum I29 to raise or lower pendulum bob I25 depending upon the direction in which the cam wheel is rotated. Cam wheel I58 is adapted to be rotated at a very slow speed in the direction of the arrow in Fig. 4, thereby swinging the lower end of lever I55 outward and causing segmental gear I55 to rotate gear I53 and drum I29 in a direction to raise pendulum bob I25 through a given distance during a given period of time, for instance, to raise bob I25 from the position shown in Fig. 4 to the upper limit of its movement during a period of six hours.

After bob I25 has been raised, it may be lowered by disengaging certain gears, as will be presently explained, and then the bob may be moved downward by its own weight, spring I52 assisting the bob to rotate the several gears and shafts.

Gear I59 (Figs. 4 and 6) meshes with a gear Ill fixed to one end of a shaft I'I2 which extends through and is journaled in

frame members

56 and 57. Shaft IIZ has a gear I'I3 journaled thereon (Fig. 6) and urged by a spring II i against a friction disk I which is fixed to shaft H2 and forms with gear I73 and spring I I I a friction clutch which permits the controller to be manually adjusted and also prevents damage to the mechanism should it stall as by bob I25 being raised too high.

Gear I73 meshes with a gear I76 (Figs. 5 and 6) fixed-upon a shaft III which is journaled in frame members 56 and 5'I and has a gear I78 fixed thereon. Gear I78 meshes with a gear IIII journaled upon a stub-shaft I86 carried by a plate IBI (Figs. 1, 5, 6 and 10), which is pivoted near its front end to frame member 5? by means of a trunnion I92 upon which it may be rocked to disengage gear I79 from gear I'I8 as shown in Fig. 10.

The rear end of plate IISI is supported by an adjusting screw I93 which normally engages the top of frame member 57 and is threaded through an arm I which is fixed to the rear part of plate I III and extends laterally from the upper edge thereof. By turning screw I83, plate IBI may be so adjusted that gear I79 meshes properly with gear I78.

Gear I19 has a gear I85 fixed for rotation therewith and in mesh with a gear I86 which is journaled upon a stub-shaft I8? fixed in plate I8I. Gear I86 has a gear I68 fixed for rotation therewith and in mesh with a gear I89 fixed upon a shaft I96 which is journaled in frame member 56 and in the end of trunnion I82 as shown in Fig. 1 so that plate I8I, when swung upon trunnion I82, turns about the axis of gear I99 which remains stationary.

Shaft I96 has been shown in Fig. 1 as being connected by a tongue and slot connection to the output shaft of a reduction gear I9I which is connected to and driven by a synchronous electric motor I92 carried by frame member 56. Reduction gear NH and motor I92 are ordinarily combined in a single unit which may be obtained in the open market from manufacturers of electric clocks.

The arrangement is such that, when motor I92 is energized, cam wheel I58 may be rotated at a very slow speed so that the speed of motor I may be varied throughout a given period of time at either a uniform or a non-uniform rate according to a predetermined schedule as determined by the contour of cam wheel I58. That is, electric motor I92 and the mechanism associated therewith constitute a secondary chrono- F metric mechanism for controlling the speed of the primary chronometric mechanism.

If the speed of motor I is to be kept constant, the mechanism for changing the pendulum length is unnecessary. If the speed of motor I is to be adjusted at the will of the operator and then kept constant by the controller, shaft I 98 may be connected directly to the output shaft of an ordinary electric motor which is manually controlled as by means of a push button switch. If the speed of motor I is to be kept proportional to the speed of an external moving body, shaft I99 may be driven from that body through intervening mechanism as shown in the application referred to above.

In order that the operator may adjust the controller manually, shaft I'IE (Fig. 6) has fixed thereon an adjusting knob I93 by means of which shaft I52 and the gear III fixed thereon may be rotated manually, friction clutch lit-I75 permitting shaft I12 to be rotated while gear H3 is held stationary due to it meshing with gear H5. Gear I?! will rotate gear I59 and thereby rotate cam wheel I58 to adjust the controller.

When motor I92 is energized, it will rotate gear I59 through the above described intervening mechanism in a counterclockwise direction as viewed in Fig.4, thereby causing cam wheel I58 to rotate in the same direction and move roller I51 and the lowfi nd of'bell crank lever I55 toward the right so tksegmental gear I54 on the upper end of lever I55 will rotate gear I53 and thereby rotate drum I29 which will wind ribbons I26 and I21 thereon and gradually raise pendulum bob I25.

After pendulum bob I25 has been raised, it may be permitted to descend by moving gear I18 out of mesh with gear I18. For this purpose, a release lever I96 has one of its ends connected to plate I8I and its other end in contact with a release button I91 which is arranged'in a socket I98 formed in casing 55 as shown in Figs. 4, 5 and 7. Button I91 is normally retained in its inoperative position by a spring I99 arranged around it within socket I98.

In order that lever I96 may be adjusted so that its front end will remain substantially in contact with the lower end of release button I91, it is adjustably connected near its rear end to plate I8I. As shown, lever I96 is connected to plate I8I by a pivot 200 and its upper edge is engaged at a point beyond pivot 200 by an adjusting screw 20I which is threaded through a flange 202 formed upon the upper edge of plate I8I. By turning screw 20I, lever I96 may be so adjusted that its front end will be substantially in contact with the lower end of release button I91 when gear I19 is meshing properly with gear I18.

When release button I91 is depressed, lever I96 will swing plate I8I upon trunnion I82 and thereby raise gear I19 out of mesh with gear I18. Then, the weight of pendulum bob I25 and the force exerted by spring I62 will be able to rotate the several shafts and gears so that pendulum bob I25 may descend. In order to stop the pendulum bob at a predetermined point in its downward travel, trip arm I66 is adapted to engage a suitable stop, such as the pin I51 (Figs. 4 and 6) which carries roller I51 and is fixed to the lower end of lever I55.

Just before trip arm I66 engages pin I51, the outer end thereof engages a cam 206 arranged upon the lower end of a trip lever 201 which is pivoted intermediate its ends upon shaft I56 between lever I55 and frame member 51. The upper end of trip lever 201 is urged rearward by a spring 208 but it is normally restrained from rearward movement by a flange .209 formed upon and permit the rear part of plate I8I to fall but,

screw I83 will engage flange 208 and hold gear I19 out of mesh with gear I18, thereby permitting pendulum bob I25 to descend.

As pendulum bob I25 moves downward, it and spring I62 will rotate the several shafts and gears and thereby cause trip arm I66 to revolve about the axis of shaft I60. When pendulum bob I25 approaches the limit of its downward movement, trip arm I66 will engage cam 206 and swing trip lever 201 upon shaft I56 to move flange 209 from beneath screw I83, thereby permitting the rear end of plate I8I to fall and gear I19 to mesh with gear I18.

Just as flange 209 moves from under adjusting screw I83, trip arm I64 engages pin I51 and stops further descent of the pendulum bob so that gear I18 ceases to rotate before gear I19 meshes therewith. In order to provide ample time for gear I18 to cease rotating before gear I19 meshes therewith and to cushion the fall of plate I8I, a dashpot is ordinarily provided.

As shown in Fig. 11, a dashpot plunger 2I2 is pivoted at its upper end to an arm 2I3 which is fixed to plate I8I. The lower end of plunger 2I2 has a head formed thereon and loosely fitted in a dashpot 2M which is formed in frame member 51 and connected by a channel 2I5 to a reservoir 2I6 also formed in frame member 51. The lower end of dashpot 2I4 is closed by a. check valve 2I'I which permits liquid to flow freely from reservoir 2I6 into dashpot 2M but prevents it from flowing in the opposite direction.

When plate IBI falls, plunger 2I3 tends to eject liquid from the lower part of dashpot 2M but check valve 2 I 1 prevents it from passing into channel 2I5 so that liquid must be squeezed out of the lower part of dashpot 2I into the upper part thereof between the wall of the dashpot and the periphery of the plunger head, thereby retarding the downward-movement of plate I8I. When plate I8I is raised, plunger 2I2 will move upward with it and check valve 211 will permit liquid to flow freelyfrom reservoir 2I6 through channel 2 I5 into the lower part of dashpot 216 to keep it filled.

Reservoir 2I6 is supplied with liquid from an oil pan 2I8 which is arranged above the controller mechanism and supported from frame members 56 and 51 by four posts 2I9. Pan .2I8 is supplied with oil from a suitable source, such as gear pump 2I, through a channel not shown. The bottom of pan 2I8 has a. plurality of small perforations 220 formed therein through which oil may flow to lubricate all parts of the controller mechanism and keep reservoir 2I6 filled. In order to prevent motor I92 from being bathed by the lubricating oil, it is ordinarily arranged beneath a shield 22I which is fastened to frame member 56.

It has been previously explained that, if the prime mover being controlled drives ring gear 50 (Fig. 8) of differential BI at a speed which varies relative to the speed of escape wheel I08, shaft IOI will be rotated in one direction or the other depending upon whether the speed of gear 50 increases or decreases relative to the speed of.

escape wheel I08. In order to maintain the speed of the prime mover proportional to the speed of escape wheel I08, the rotary movements of shaft IOI are utilized for operating valve 30 (Figs. 12 and 15) to thereby vary the speed of the prime mover. I

Movements are transmitted from shaft IOI through an arm 226 which is fixed to sleeve I I 2 or formed integral therewith as shown in Figs. 2, 3, 7, 8 and 15. Arm 225 is pivoted at its free end to the upper end of a lever 226 which is pivoted intermediate its ends upon a pin 221 and has its lower end connected by a link 228 to the stem 229 of valve 30.

From an inspection of Fig. 15 it will be obvious that, if pin 221 is stationary and if the speed of motor I decreases or the speed of escape wheel I08 increases so that shaft I0! is rotated in a counterclockwise direction, arm 226 will swing the upper end of lever 226 toward the right and cause the lower end th'ereofto shift valve 30 toward the left to permit liquid from gear pump 2| to flow to cylinder l8 and increase the displacement of pump 3 with a resultant increase in the speed of motor I; and that, if the speed of motor 1 increases or the speed of escape wheel I08 decreases so that shaft IOI is rotated in a clockwise direction, arm 225 will swing the upper end of lever 226 toward the left and cause the lower end thereof to shift valve 30 toward the right to permit liquid to escape from cylinder I8 and thereby permit servo-motor -42 to decrease the displacement of pump 3 with a resultant decrease in the speed of motor I.

When valve 30 is shifted in one direction or the other to effect movement of slide block l and thereby correct a variation in the speed of motor I relative to the speed of escape wheel I08, it is necessary to transmit motion from slide block l0 back to valve 30 in order to prevent pump 3 from hunting.

For this purpose, a push pin 233 extends through the wall of casing 55 and has one of its ends in'contact with slide block I0, as shown in Fig. 15, and its other end in contact with a lever arm 234 as shown in Figs. 1, 4, 6, 7, 9 and 15.

Lever arm 234 is fixed upon a shaft 235 which is supported at its ends in bearings 236 and 23l carried by the substantially U-shaped lower part of a hanger 238 at opposite ends thereof. Hanger 238 is pivoted at its upper end to frame members 56 and 51 by means of a shaft 239 so that shaft 235 may be moved toward and from slide block it as will be presently explained.

The vertical part of hanger 235 has a stop screw 240 threaded therethrough and in contact with one end of a push pin 24| which is slidably fitted in a suitable bore formed in frame member 57 and has its other end in contact'with cam ring I61 as best shown in Fig. 9. The arrangement is such that the lower part of hanger 235 and shaft 235 will be swung toward or from slide block i6 when cam ring I6? is rotated.

Shaft 235 has a lever 245 (Figs. 6 and 7) journaled thereon and a vertical lever arm 246 fixed thereon alongside lever 245 and provided at its upper end with a flange 247 which overlaps a boss 248 and a fiange 249 formed upon lever 245. An adjusting screw 25!) is threaded through boss 248 into contact with flange 24?. A- bolt 25H is threaded into flange 241, extends through flange 249 and has a helical spring 252 arranged there on between flange 249 and a suitable collar which is retained in position upon bolt 25i. Spring 252 urges flange 249 toward flange 24? and holds adjusting screw 250 in contact .with flange 24?, thereby causing lever 245 to normally operate as an integral'part of lever arm 246 and shaft 235. By turning screw 250, the angle between lever arm 234 and lever 245 may be varied to thereby adjust the controller in respect to slide block It.

Lever 245 is connected near its upper end by a link 255 to a lever 256 intermediate the ends thereof.

Levers

245 and 256 have a plurality of holes formed therein for connecting link 2255 thereto in various positions to thereby adjust the controller. Lever 256 is pivoted at its upper end to frame member 56 and urged toward the right in respect to Fig. '7 by a spring 251 which holds lever arm 234 in contact with push pin 233 and holds stop screw 250 (Fig. 9) against push pin 24!.

The lower end of lever 256 is pivoted to one end of a link 258 which has its other end oon-= nected to lever 226 by the pin 221 upon which lever 226 is swung to operate valve 30.

In order that the accuracy of the controller may not be impaired by slack or lost motion in the mechanism through which motion is transmitted from arm 225 and slide block Hi to valve 30, and to avoid the necessity of closely and accurately fitting the pins which connect the several parts of that mechanism, spring means are provided for taking up all slack or lost motion in that mechanism.

Spring 251, by causing lever arm 234 ,to press push pin 233 firmly against slide block i0, takes up all slack in the joints between link 255 and

levers

245 and 256 so that there is no lost motion in that part of the mechanism.

In practice, all slack in the other parts of the mechanism is taken up by other springs and auxiliary levers which have been omitted from the drawings to avoid complicating the views. In lieu thereof, the controller has been shown in Fig. 15 as being provided with a light flexible spring 259 which urges valve 30 toward the right and thereby takes up all slack in the joints between valve stem 225, link 2213, lever 226, link 258 and lever 256 so that there is no lost motion between arm 225 and valve 30 or between slide block it and valve 35. Spring 259 or its equivalent, while strong enough to take up the slack in the joints mentioned, is so light and flexible that it does not add appreciably to the power required to swing arm 225.

OPERATION When motor i is operating at the desired speed and driving ring gears 55 and as of differential at in a clockwise direction as viewed in Fig. 15, ring gear as will tend to carry planet pinion at around with it and thereby tend to rotate shaft ifii in a clockwise direction. However, weight H will oppose a definite turning moment to rotation of shaft ifii and thereby cause sun gear M4 to rotate in a counterclockwise direc tion and drive the chronometric mechanism.

Each time a pallet lit or Eliii (Fig. 13) engages a tooth of escape wheel iiiii, it will momentarily arrest rotation of sun gear 555 (Fig. 8), and thereby cause shaft lei to rotate through a small angle in a clockwise direction as viewed in Fig. 15 and raise weight 599. Each time a pallet M5 or 93! releases a tooth of escape wheel let, weight He will fall and rotate shaft till through a small angle in a counterclockwise direction, and then a pallet will engage another tooth of escape wheel E68 and again momentarily arrest rotation of sun gear i5 3. Weight H6 in falling will impart a turning moment to sun gear W4 through pinion 96. The effect is that weight M5 is raised intermittently by power derived from motor 8 and falls intermittently, but continuously transmits a definite turning moment to sun gear M4 to enable it to drive the chronometric mechanism. Sun gear 904 will thus be rotated intermittently but, since the oscillation period of a constant length pendulum remains constant, the overall or net speed of sun gear Hi4 will be constant as long as cam wheel iiiii (Fig. remains stationary.

If motor ,i is rotating at exactly the desired speed as determined by the adjustment of the chronometric mechanism, shaft lei will be rotated through the same limited angular distance in each direction of rotation and cause arm 225 to oscillate through a very limited range which has a fixed angular position as long as motor 5 continues to rotate at exactly the desired speed. Oscillation of arm 225 through this limited range causes valve 30 to be oscillated through a range which is so small that the adjustment of pump 3 is not materially affected. In practice, it is found that such limited oscillation of valve 30 causes the speed of motor I to vary momentarily much less than one-tenth of one percent above and below the desired speed. Since such slight momentary variations are immaterial in actual practice, they have been disregarded in the foregoing description and will be disregarded hereinafter.

If motor I deviates from the desired speed and thereby drives the differential gears and 93 at a different speed, or if pendulum bob I25 is raised or lowered and thereby causes sun gear I04 to rotate at a different speed, the variation in the relative speeds of gears 93 and IM will cause planet pinion 98 to be carried around sun gear I05 in one direction or the other and thereby rotate shaft IOI in one direction or the other.

If the speed of motor I decreases so that the speed of

gears

58 and 93 is decreased or if pen- -dulum bob I25 is raised so that the speed of sun gear I84 is increased, shaft IIlI will be rotated in a counterclockwise direction as viewed in Fig. 15 and cause arm 225 to swing the upper end of lever 225 toward the right. Lever 226 will pivot upon pin 221 and shift valve 30 toward the left and permit liquid to flow from gear 2i to cylinder I8 and shift slide block II) toward the left, thereby increasing the displacement of pump 3 and consequently increasing the speed of motor I as previously explained.

Since push pin 233 is held in contact with slide block In by the action of spring 251 (Figs, '7 and 15), movement of slide block I0 toward the left permits push pin 233 and the lower end of lever arm 234 to move toward the left, shaft 235 to ro tate in bearings 23B and 237 and the upper end of lever 2 35 and link 255 to move toward the right, thus permitting spring 257 to move the lower end of lever 255 and link 258 toward the right so that pivot pin 22'! is moved toward the right substantially simultaneously with the movement of slide block In toward the left with the result that valve 39 is returned to its neutral position and further adjustment of pump 3 ceases as soon as arm 226 ceases to swing toward the right. Until another variation occurs, lever 228 will remain in this new position, its upper end having been shifted toward the right to open valve 30 and its lower end having been shifted toward the left to close valve 38 during the above described adjustment of pump 3.

If the speed of motor I increases so that the speed of

gears

50 and 93 is increased or if pendulum bob I25 is lowered so that the speed of sun gear I8 3 is decreased, shaft IiJI will be rotated in a clockwise direction as viewed in Fig. 15 and cause arm 225 to swing the upper end of lever 226 toward the left. Lever 225 will pivot upon pin 221 and shift valve 30 toward the right to permit liquid to escape from cylinder I8 and thereby permit servo-motor II-I2 to shift slide block I 0 toward the right to decrease the displacement of pump 3 with the resultant decrease in the speed of motor -I as previously explained.

As slide block In moves toward the right, push pin 233 will swing the lower end of lever 235 toward the right and thereby rotate shaft 235 in

bearings

236 and 237 and swing the upper end of lever 245 and link 255 toward the left. Link 255 will swing the lower end of lever 25B and move link 258 toward the left and thereby move pin 221 toward the left substantially simultaneously with the movement of slide block I0 toward the right so that valve 30 is returned to its neutral position and further adjustment of pump 3 ceases as soon as arm 225 ceases to swing toward the left. Until another speed variation occurs, lever 226 will remain in this new position, its upper end having been shifted toward the left to open valve 30 and its lower end having been shifted toward the right to close valve 30 during the time the displacement of pump 3 was being reduced to correct the variation in the speed of motor I.

The control mechanism is thus capable of maintaining the speed of motor I proportional to a standard or measuring speed as determined by the adjustment of the chronometric mechanism. That is, it will keep the motor speed substantially constant as long as the pendulum length remains constant and itwill keep the motor speed at a predetermined ratio to the speed of sun gear I04 when the pendulum length is varied slowly. If pendulum bob I25 should be raised or lowered at high speed, the adjustment of motor speed would lag behind the adjustment of the measuring speed.

If the axis of shaft 235 remained stationary during extensive adjustment of the controller to vary the speed of the prime mover through a wide range or if the speed of the prime mover should tend to vary so much from the desired speed that arm 225 would tend to swing lever 22 6' beyond the range it can accurately adjust valve 39, arm 225 would engage one or the other of two stops 260 and 25! which are fixed in frame member 56 upon opposite sides of arm 225. Then, continued rotation of shaft IIH would cause detent H6 to ride over a tooth of ratchet wheel II5, thereby keeping lever 228 within its useful range and preventing damage to the controller.

In order that continued adjustment of the controller to vary the speed of motor I through a wide range may not cause lever 226 to be shifted beyond the range in which it can accurately adjust valve 30, cam ring I67 (Figs. 4 and 9), push pin 2M and hanger 238 (Figs. 4, 6 and 9) are provided. When motor I92 (Figs. 1 and 7) is energized and gear I19 (Figs. 5, 6 and 10) is in mesh with gear I78, motor I92 will rotate cam wheel I58 (Figs. 4 and 9) which will swing lever I upon shaft I56 to gradually raise pendulum bob I25 and thereby cause slide block II] (Fig. 15) to be gradually moved toward the left in respect to Fig. 15 to increase the speed of motor I as previously explained. Since cam ring IE1 is fixed for rotation with cam wheel I 58, it will be rotated in unison therewith and cause push pin 25F to swing hanger 238 upon shaft 239 and thereby move shaft 235 in the same direction that slide block i8 is moved. that is, toward the left in respect to Fig. 15. The contour of cam ring I6? is such that shaft 235 is moved at a rate proportional to the rate at which slide block ID is moved so that lever 226 is displaced but little from its initial position during the time that the speed of motor I is being increased by raising pendulum bob I 25.

With the controller constructed and adjusted as shown, the speed of the prime mover controlled by the controller will be gradually increased when motor I92 is energized to raise pendulum bob I 25 as previously explained. If it is desired to employ the controller to gradually decrease the speed of a prime mover, pendulum bob I25 would be raised manually by turning knob I93 and the controller would be adjusted to gradually lower bob I either by reversing cam wheel I58 and cam ring IE1 or by reversing the direction of rotation thereof.

In one case, it is simply necessary to turn cam wheel I58 and cam ring I01 over in respect to gear I59. In the other case, it is simply necessary to reverse the direction of rotation of gear I59 either by changing a part of the gearing or re-. versing the direction of rotation of the motor which drives the gearing. In both cases trip ann I64 would be shifted to a position in which it would not interfere with trip lever 201.

Fig. 16

This figure illustrates a different method of operating the control valve. As shown, control valve is urged toward the right by a spring 210 which has one of its ends connected to the stem 229 of valve 30 and its other end connected to thecasing in which valve 30 is fitted and which is the same as valve casing 35 except that it has a dashpot 21I arranged upon its right end.

Dashpot 21I has a cylinder 212 formed. in its casing in communication with the bore of valve casing 35"- and a dashpotplunger 213fitted in cylinder 212 with its stem extending into the bore of casing 35 The left end of cylinder 212 is open to a drain channel 214, and the right end of cylinder 212 has been shown as being connected to drain through a channel 215 which connects the two ends of the cylinder to each other and has a needle valve 216 extending into it to restrict the flow of liquid therethrough.

The right end of cylinder 212 is connected through a check valve 211 and a channel 219 to a reservoir 219 which is kept filled with oil supplied thereto through one or more of the perforations 229 formed in oilpan 2I8. Check valve 211 permits liquid to flow freely from reservoir 219 into the right end of cylinder 212 but prevents liquid from escaping therefrom except through channel 215 through which it may flow only at a limited rate due to thethrottling action of needle valve 216.

When valve 30 is moved toward the left, liquid from reservoir 219 will fiow through channel 218 and check valve 211 into the right end of cylinder 212 and move plunger 213 with it, reservoir 219 being arranged high enough to provide sufficient head to enable the liquid to move plunger 213 in cylinder 212 and to keep its stem in contact with the end of valve 30.

When valve 30 is moved toward the right by spring 210, plunger 213 must eject liquid from the right end of cylinder 212 but check valve 211 will be closed so that this liquid must flow through channel 215 past needle valve 216 which will limit the flow of liquid therethrough and thereby retard the movement of valve 30.

Valve casing 35 is connected in circuit in the same manner that valve casing 35 is connected in circuit and as shown in Fig. 15 so that, when valve 30 is shifted toward the left, liquid may flow to cylinder I8 to increase the displacement of pump 3 with the resultant increase in the speed of motor I and, when valve 30 is shifted toward the right, liquid may escape from cylinder I8 and permit the displacement of pump 3 to be decreased with the resultant decrease in the speed of motor I.

Valve 30 is adapted to be moved toward the left by a lever 226 which is pivoted at its upper, end to arm 225, pivoted at its lower end to link 258 by a pin 221 and extends alongside an abutment 280 fixed to valve stem 229 so that, when the lower end of arm 225 swings toward the left, lever 22$ will engage abutment 280 and move valve 30 toward the left.

It hasbeen previously pointed out that, when motor I is operating at the desired speed and driving ring gears and 93 of differential M in a clockwise direction as viewed in Fig. 15, shaft IOI will be rotated in a clockwise direction and swing the lower end of arm 225 toward the left through a small angle each time a pallet I30 or I3I '(Fig, 13) engages a tooth of escape wheel I08, and it will be rotated in a counterclockwise direction and swing the lower end of arm 225 toward the right each time a pallet I30 or I3I releases a tooth of escape wheel I08 and permits weight II 9 to fall.

Since shaft I0! is rotated in a clockwise direction due to rotation of gear 93, the lower end of arm 225 will be swung toward the left at a relatively slow speed and, since shaft I 0| is rotated in a counterclockwise direction by weight II9 when falling, the lower end of arm 225 will be swung toward the right at a relatively high speed.

The arrangement is such that, when a pallet I30 or I3I engages a tooth of escape wheel I08 and causes shaft IOI to be rotated in a clockwise direction as previously explained, arm 225 will swing lever 226 upon pin 221 and lever 226 will engage abutment I80 and shift valve '30 toward the left and, when the pallet disengages a tooth of the escape wheel and'permits weight II9 to fall and rotate shaft IOI in a counterclockwise direction, arm 225 will swinglever 226' out of contact with abutment I 8 0 and permit spring 210 to move valve 30 toward the right. The movement of valve 30 toward the right under the influence of spring 210 is retarded by dashpot 21I so that, as long as the speed of motor I remains constant, valve 30 moves but little ,toward the right before lever 226 again engages abutment I80 and moves it toward the left. The result is that, as long as the speed of motor I remains constant, valve 30 is oscillated through such a small range that its movement has no material effect upon the displacement of pump 3. If the speed of motor I varies from the desired speed as measured by the chronometric mechanism, arm 225 will be oscillated through a different range and thereby cause valve 30 to be shifted to correct that variation in speed as previously explained.

The invention herein set forth is susceptible of various modifications and adaptations without departing from the scope thereof as hereafter claimed.

The invention is hereby claimed as follows:

1. In a chronometric controller, the combination of a three-legged differential having a first leg driven from an external source of power and a second leg provided with a weight which resists rotation thereof and thereby causes rotation of the third leg, and a chronometric mechanism having an escapement connected to said third leg to control the speed thereof and permitting said third leg to rotate intermittently and thereby cause said weight to be alternately raised and permitted to fall, said weight being raised by power derived from said external source and transmitting this power when falling to said chronometric mechanism to drive the same.

2. In a chronometric -mechanism, the combination of a pendulum bob, means including an escapement for transmitting power impulses to