US2246207A - Drive mechanism - Google Patents

Description

June 17, 1941.. E, E, HEWETT 2,246,207

DRIVE MECHANISM Filed July 28, 1939- INVENTOR ATTORN EY Patented June 17, 1941 Ellis E. Hewitt, Ed'g'ewood, Pa, assignor to The Westinghouse Air Brake Company, Wilmerding, Pa.-, a corporation of Pennsylvania Application July 28. 1939, Serial No. 287,084

16 Glairns.

This invention relates to air compressors and more particularly to a drive mechanism therefor.

The Diesel type internal combustion engines employed for driving, either directly or indirect-' ly, locomotives such are. used for hauling certain modern, high speed, stream-lined trains, operate over a considerable range of speed which varies from a relatively low idling speed, employed when a train is stopped or when coasting down a grade, to a relatively high speed for producingsufficient torque to haul the train at high speed.

On these locomotives the air compressors which furnish compressed air for the control of the brakes on trains, are usually driven directly from the Diesel engines or from any other suitable source of power which is dependent upon the operation of said engines, and which there- From the above remarks it, will be apparent that the compressed air requirements on a train are independent of the speed ofthe driving en? gines or the like, since under certain conditions the demand for, compressed air is greatest when the engines are operating at idling speed. 1 The drive for the air compressors should therefore be such as to effect operation thereof at substan- 1 tially the most effi'cient speed when the air despeed locomotives operate continuously, so it is fore varies in speed in proportion to the engine speed. The compressors are thus operated at relatively high speed and capacity under high engine torque conditions at which time. the brakes on the train arereleased and the requirements for compressed air on the train are at a minimum. When a train is coasting down a grade with the Diesel engines idling, the requirements for compressed air onthe train are at a maximum for controlling the brakes ,on the train, but at this time, as will be evident, the air compressors operate atrelatively low speeds proportional to the idling speed of the en-. gines. The output of the compressors is thus reduced when the air requirements on the train are greatest. Obviously if a compressor is capable of producing a. sufficient quantity of compressed air at the low idling speed of the Diesel engines toinsure safe braking of the train,.then an excessive and'a substantially useless amount of compressed air is. provided when the Diesel engines are operating at high speed with the brakes on-the train released. Air compressors of very large size, Weight andcost are therefore re-. quired to adequately meet the requirements on these trains, and incase the compressors are designed for their greatest output efliciency at relatively low speeds Where the air requirements are usually greatest, then it will be evident that when the compressors are operating. at higher. speeds, an excessive waste of compressed air results. Further, the operation of the compressors at these high speeds is inefiicient and accompanied with a Waste of operating power as Well asexcessive heating of the compressors, excessive oil consumption and undue wear of the parts f compressor.

therefore obvious that except-when the air demands are heavy and up to the capacity of the air compressors, the compressors could be operated at areduced speed with a resultant reduction in the wear of parts, of oil consumption and also excessive heating of the compressors could be avoided. Further, the compressors could be designedto operate at the desired, most efilcient speed when the air requirements of the train are greatest and at all other times operate at reduced speeds and thus overcome the difficulties or shortcomings incident to the. systems of compressor drive now in use onhigh speed trains, asabove described.

,One object oi, the present invention is to providean improved drive for air compressors from a variable speed prime mover adapted to overcome the difficulties of conventional types of drive now in use in high speed trains, as above described. 4 -Another :object of the present invention is to provide an improved drive for air compressors froma variable speed primemovenadapted to drive the compressor at a speed in proportion to the air requirements on the train, that is, at a relatively high, most eflicient speed at the time the air requirements on the train are greatest and at a reduced speed at all other times or when the air requirements on the train are at a minimum.- 1

It is important to note that in order'to meet the heavy demands for compressed air required for braking a train a compressor need only operate at capacity a relatively small portion, such as twenty five percent, of the running time of a train. During the other portion of the running time of the train the air demands on the train are relatively low and in. high speed trains where these compressors operate continuously they need therefore onlyoperate at relatively low speed to meet such reduced demands. By controlling the speed of the compressor in accordance with the air requirements on the train it will be evident that the compressor will operate the major portion of the running time of a train at a relatively low speed and thereby effect a very material saving in actuating power and lubricant with a resultant lengthening of the life of the compressor and complete avoidance of excessive heating thereof.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawing, the single figure is a diagrammatic, sectional view of the improved drive mechanism shown connecting a prime mover to an air compressor.

Description of parts In the drawing the reference numeral I indicates a prime mover of any desired, variable speed type such as a Diesel, internal combustion engine which is provided with a crankshaft 2 extending from one end thereof and adapted to operate at Varying speeds over a range between an idling speed and a high speed corresponding to-the speedsof such engines as obtained in high speed train service. A bevel gear 3 is adapted to. be turned by the crankshaft 2 in any desired manner, but. for the purpose of illustration is shown secured directly to the end of said shaft so as to rotate with and at the same speed as the shaft.

The reference numeral 4 indicates an air compressor adapted to be operated from the engine L The air compressor 4 may be of any desired constructionbut for the purpose of illustration comprisesa casing, a crankshaft 5 journaled in a bearing 6 inthecasing and one or more pistons (not shownloperatively connected to the crankshaft for reciprocation thereby. These pistons are adapted upon reciprocation to operate in the-'well known manner to draw air from the atmosphere through an intake pipe I and to compress said air and discharge same into a discharge pipe 8 which in the present embodiment of the invention leads to a storage reservoir-9. This reservoir may be a main air supply reservoir on a locomotive and is employed for storing up a supply of compressed air delivered from the air compressor for use in con trolling the brakes on the train or for other uses.

The bevel gear 3 meshes with a bevel gear I0 which is secured to a vertically operating shaft II for turning said shaft. The shaft II is journaled at its lower end in a suitable bearing member I2 while the upper end of the shaft is rotatably mounted in a suitable bore provided in a nut I3. The nut I3 is screw-threaded into a suitable opening provided in a member I4 which is secured in any desired manner in predeterminedrelation to the bearing member I2 so as to rigidly support the shaft II at right angles to the axes of the crankshafts 2 and 5.

A sleeve I6 is slidably mounted on the shaft II and a pin II extends through said shaft into oppositely disposed slots I8 provided in the sleeve I 6 for turning said sleeve with said shaft, said slots providing for limited movement of said sleeve longitudinally of the shaft I I.

The upper end of the sleeve I6 is telescoped within. and supported by a sleeve I9 which is secured at its upper end to the inner race of a ballbearing 29 secured in member I4 in coaxial alignment with the nu-t I3. This ball bearing 20 supports the sleeve I9 against movement longitudinally of the shaft II. The sleeve I9 is provided at its lower end with two longitudinally extending slots 2| disposed opposite each other. The sleeve I6 is provided on each of its opposite sides with a driving finger 22, the two fingers being mounted to slide in the two slots ZI.

The sleeve I9 is provided adjacent the hearing 20 with a pair of oppositely disposed ears 23. One end of a lever arm 24 is pivotally connected to each of the ears 23' while at the other end of said arm there is provided a mass in the form of a governor weight 25. Each of the arms is pivotally connected intermediate its ends to one end of a link 26 the opposite end of which is pivotally connected to an ear 2'! provided on the sleeve I6, it being evident that the two links 26 and ears 21 are arranged opposite each other at opposite sides of the sleeve I6.

The sleeve I6 is provided in its upper end with a counterbore 28 which opens to a bore extending through the sleeve IS in axial alignment withthe lower face of the nut I3. A governor control spring 29 is disposed in the counterbore 28, with the lower end of the spring engaging the bottom of the c'ounterbore while interposed between the upper end of said spring and the adjacent face of the nut I3 is an antifriction bearing 30 adapted to provide free rotation of the spring 29 with the sleeve I5 and I9 relative to the nut I3. The sleeve 7 I6 is provided at its lower end with a disk 3| the peripheral face of which is disposed in frictional driving engagement with the friction face 32 of a driven disk 33 which is secured to the end of the compressor crankshaft 5 for turning said crankshaft and for thereby operating the air compressor 6.

Movement of the sleeve I6 lengthwise of the shaft II is adapted to effect movement of the disk 3| radially of the friction face of the driven disk 33, such movement being limited by engagement of the pin IT with the ends of the slots I8.. These slots are of such length as to permit movement of the disk 3| from near the center of the disk 33 as shown in the drawing outwardly to a position defined by engagement of said pin at the opposite ends of slots I8 and in which the peripheral edge of the disk 3|, is in engagement with the disk 33 adjacent its outer peripheral edge.

The nut I3 is provided on its upper face with an integrally formed gear 34 beyond which there extends a shaft 35 journaled at its outer end in the member I 4 for cooperation with the nut to support said nut in coaxial relation with the shaft II. A gear rack 35 is slidably mounted in suitable bearings in the member I4 at right angles to the axis of the gear 34 and is provided with gear teeth meshing with those on said gear. One end of this rack is connected for movement with a piston 31 which has at its outer face a chamber 38 connected through a pipe 39 to pipe 8 leading to reservoir 9 whereby fluid at the pressure delivered by the air cornpressor 4 and acting in said reservoir will at all times be in said chamber acting on the piston 31.. .At the opposite side of the piston 3'! there is provided a non-pressure chamber 4!! which is open to the atmosphere through a breather port M and in which there is provided a release spring 42 which encircles the rack 38 and bears at one end against the end of said chamber and at the opposite end against the piston 31 for opposing movement of the piston by the air pressure acting in chamber 33.

The, spring-42 islso designed" that when the pressure of-air delivered-by: the compressorl to reservoir 9 and acting. in chamber- 38 exceeds a chosen. degree-,- theipiston 31-iwillhbemmoved against said spring: and into engagement with the end wall 4310f the non-pressure chamber 40, :but. when said pressurezqis, less thansaid chosen degree, the springi42. willrmove the *DiS-r ton 31 awayffrom said ,wall in: the direction of the right hand to a position depending upon the degree of reduction in air pressure in chamber 38'below said chosen pressure; I 1 'It will be evident that since. the pistonz3'l is connected through the gear rack 3Gto-the gear 34, movement of said pistoniwill efieet rotation ofsaid gear and: thereby of the nut;vl3. The screw-threads on the nut [3c and; those in the member '14 with which saidnut cooperates are sodesigned that as the piston 3'liis'moved against the spring 42:said:nut'upon being turned will be moved in the direction 4 of the rack 36'and thus act to relieve the pressure of the governor control spring- 29 on the sleeve I6. Whenithe piston 3'l1'is movedbythei action;of the spring 42 inthe oppositedirection;the rack 36 and thereby the gear will operate. to turnthe nut I3 and move same in a direction awayfrom the rack 36, so as to thereby increasethe pressure ofthespring-ZB acting'ion' the sleeveJB:

Operation v When the engine I isoperating and turning the'crankshaft 2 the bevel gear 3.is operated to turn the. gear in and thereby the shaft II. ;This rotation of the shaft ll acts through the pin I! to turn the sleevel5 and, thereby the disk 3|. Since the disk 3| is in frictional driving contact with the compressor disk 33, rotation of: disk 3! effects rotation of said compressor'disk' and thereby operation of the compressor 4,-to compress air into the pipe 8z-and thence to the main reservoir 9 and pipe 39 leadingto pressurechamber 38 at one side of the speed change piston 31;

Rotation of the sleeve l6. actsthrough the ears 2'! to rotate the links 26 'and thereby the governor arms 24 and weights 25 and through-.theears. 23 to turn the sleeve'lfl inthebearing 2lleprovided in the member l4; Due tothe action poi-centrifugal force on the governor balls 25saidballs will move outwardly away from the sleeve; 16 and duringsuch movement will move thersleeve it along the shaft ll in the direction of the nut l3. This movement of the sleeve acts to compress. and thereby increase the force of spring 29' opposing, such movement and-will continue untilthe force of said spring is'increased to 'a degree suiiicient to counteract the action of cone trifugal force'onthe governor balls 25'. If the speed of rotation of the. engine crankshaft 2. and thereby ofthe shaft H and governor balls 25 is increased said balls will'operate to'drawthe sleeve I6 still further in-the direction of the nut I 3 until the pressure of the spring 29' is further increased sufficientlyto counteract the increased action of centrifugal force on the governor balls 25. In case the'speedof rotation of the engine crankshaft is reduced,' the reduced action of centrifugal force onthe governorba-lls 25 permits the spring 29 to expand and-move the sleeve l6 away from the nut I3; to a position in which the pressure of said spring is re-- duced to a degree where it is counterbalanced by the action of centrifugal fo'rceonthegovernor weights l9. Inother'words thegovernor device including-thearms24, balls 25 and links 28zwill;op erate to: position the-sleeve IS on the shaft lI:ina:positioncorresponding to the speed ofthe'drivingaengine 1|; 7, V

Movement of'the sleeve lfi in the direction of the nut l3 effectsmovement of the driving-disk 3i outwardly: towardnthe peripheral'edge of the driven disk 33 and said driving disk will assume a .positionlwith respect to the friction faceoi the drivencdisk corresponding to theipositionob: tained by, the-governorhalls 25 as determined bylthe'speedw of operation of the engine .l L. the speed of:theengine If is increased thedrivingv disk 3-l will .be movedv outwardly. further towardthe peripheral edge of the driven disk 33, while in caseithe' speed'of'theengine is reduced theidriving-disk 3| will be moved in the opposite direction towa-rd the center of the driven disk 33;

The speed: with which the air compressor is operatedfrom theengine l depends upon-the length of patnon thedriven disk 33 traversed by the peripheral face of the driving disk 3l and it will be obvious 'that asthe driving diskz3'l is movedoutwardlyitoward the edge of therdriven disk'33 the length, of'this pathisd correspondingly increased and since such outward movement isiin proportion tothe: increase in speed in t e: drivin engine I; it-.:wi11 'be 'evident that the speed:of:the.:air;compressor 4 willnot increase withthat iof theaengine. In; case thespeed of the engine ilaisrreduced the governoridevice including: spring; 29-- and balls l9 act :to, move thedriving disk :31: inathe direction :of the reenter of therdriven disk 33;:th'e degree of; suchw'movement depending upon the reduction in", engine speeckt In; other words"; for 'atv 'certain air pres-- sureactingxonathe pistonifl and ithereby' "holding the nuti |3L againstmovement; the-driving: disk 3| "LWill assume a "position :radiallyf of thedriven' disk: '33 dependent; upon the; engine speed; and the parts of the mechanism imay" be so designed thatsin' the: operation so far described; the 'speed of then airvcompressor will: 'remain'rsubstantially the:samexfor.. all engine speeds." 1

Let it be: assumed that thepressure'of air deliveredi'by the compressor "to reservoir -9 and actingisin 1 chamber 38' is' sufficiently low to permit spring-42:tohold the piston'31 inwits "extreme'right hand position as shown in theadraw- In this position of piston 31 and also of the nut I3' the compressor 4 is adap'ted to be operated at its maximum and most efficient speed and it willbe noted that this speed will remain" substantially constant' regardless of var: iationsinspeedof the engine L'for reasons hereinbefore described. It sho'uld however be noted thatth'e pressure in reservoir!) will usually only be-reduced sufli'ciently for the piston 31 to be'moved to the position described when a large amount of compressed air isbein'g used from the reservoir "9 for-the'cont'rol of brakes on'the' train at which-time the engine [will be idling. Howevereven though 'the engine issped up it"will have no material effect uponthe speed of the compressor ii i I Now as-the-pressure of fluid delivered by the compressor fto'thereservoir d'and acting'in chamber "as es the piston 31 11s increased and overcomesithe pressure of spring 41; th'e'pistorr 31 is -moved in 'the direction of' the nut l3 and acts-to turnthe'gear 34-and therebythe nut l3 relative to the member I4- in such a direction as to miov'e said nut toward'the rack 36 thereby permitting-anupward movement of theadjacent end of*sprin-g-29 and in efiect a-corresponding reductionin-the pressure-of-said spring-onthe sleeve IE. As the pressure of the spring on' sleeve I6 is thus relieved theaction of centrifugal force of the governor balls 25 throws said balls outwardly to a position where spring 29 is again compressedt'o'a degree sufficient to offset the reductionof pressure thereof on sleeve l6 due to th e actionof the nut I3.""Asa consequence of this action 'due'to the-increase in pressure in reservoir 9, the driving disk3l 'is pulled outwardly toward the outer peripheral edge of the driven disk 33 and thereby causes a corresponding'slowing down of the compressor 4.

'As" the pressure delivered by the compressor 4 to the reservoir 9 and piston chamber 38 is further increased; the piston 31' is moved further in the direction of gear wand thereby effects further movement of nut l3 in the direction of r'ack'=35,' whereupon the governor balls 25 are permitted to move outwardly to a new position sufficient to counteract the changed Condition of said spring and consequently effect movement of the driving disk 3| still further towards the peripheral edge of the cylinder disk 33' thereby causing a still further reduction in speed of the air compressor 4. r J I 'As the pressure of fluid delivered by" the compressor i'sstill further increased the piston 31 will continue to be moved in the directionof the gear 34 until such time as'said piston engages the Wall 43, atwhich time the nut I3'and thereby the spring '29 will be" conditioned to permit such outward movement of the balls 25 to eflect maximum slowing down of'the compressor 4:- With 'the'reservoir 9 "thus charged to the voir 9'." 5 When the-piston 29 is in its extreme left hand position the compressor will operate at its maximum and most efficient speed, while when in its'other ex't'reme position it will operate at a reduced speed; It is important to "note that the I speed o'f the compressor varies only'with the maximum pressure it is desired to carry, the nut I3 and thereby the adjacent end of the governor control spring 29 will be so conditioned, that the operation of the governor weights" 25' will be en-' abled to so position thedriving disk 3| relative to the driven disk 33 that the speed of thezcompressor will-be relatively low and below its-most efficient speed even though the engine may be operating at high speed to haul a-train; 'Under this pressure condition variations in speed of engine I will not effect any material changein speed of the compressor however, as will be evident;

If the pressure of'fluid in the reservoir-'9 and thereby in chamber 38 acting on the piston 31 is reduced sufficiently due .to being used :for the control of brakes on the train or the like, the c piston 31 and nut I3 will-operate, in amanner just the reverse of that described to change the condition of spring 29 was to provide increased resistance to the action of centrifugal force of the governor balls 25 and thereby move the balls inwardly to a position dependent upon the reduction of pressure in the reservoir 9'. A corresponding movement of the driving disk 3! toward the center of the driven disk 33-is thus effected and as, a result a corresponding increase in speed of the air compressor, 4 is obtained for, replenishing the compressed'air supply. As will be evident, the piston 31 will obtain a positionin chamber 38 which varies according to the degree of reduction in the pressure in the reservoir 9 and therefore through the action of the nut 13 and the governor device, the disk-3| will obtain a corresponding positionwith respect to the drivenv disk 33 and effect acorresponding .increase in speed of the compressor 4. -In-.other words regardless of the speed of theengine'l, the compressor 4 willoperate at-a speed depending upon the position of the piston 31 in its cylinder and therefore in accordance with the amount of compressed air used from the reserpressure 'of air delivered' thereby, since' the governorcontrol'of the drive with'engine I merely acts to offset changsin speed of said engine.- v

v e Summary o From the foregoingit will be evident that with this l'improved drive mechanism for an air-compressor which is driven from a' variable" speed prime: mover, the-compressor may be designed to operate at a certain. maximum speed for greatest efiici'ency and-the drive mechanismwill operate to prevent inoreasing the speed of the compressor over saidmaximum even though the prime *mover'mayoperate' over a considerable range of? different speeds; 1

'It' will be further noted 'that' with this impioved mechanismthe compressor will operate at its" greatest speed only when there is a heavy demand for compressed air 'and at all other times will operate "at a-relatively low speed. The compressor maythus *bedesign'ed to operate most efiicientlyfwith" aminimum -consumption" of power; it may be'of minimum size, weight 'and cost for the use intended and excessive oil consumption of the compressor and undue wear of the parts thereof as well as excessive heating of the compressor'areavoided; all pf which combined to increase the"reliability and'len gth 'of lifebfthe'compressor. Y I

While one illu'strative embodiment of the inventiori has been described in" detail it is not the intention"tolimit the scope to'such embodiment or otherwise thanby'the terms of the appended claims: v Having now'describedmy invention, what I clatim as new and desire 'tosec'ure by Letters Pat'- enlst' V 1.= In combination, an air compressor comprising a rotatable drive shaft, a" variable speed rotatable power shaft for turning'said drive shaft, a speed change mechanism connecting said shafts and adjustable tov'ary the speed ratio between said shaftsjand means-controlled jointly bythe speedofsaid power 'shaft and the pressure of the'air delivered by said'compres sor for'controlling the adjustment-of said mechanism 2; In combination, an air compressor comprising 'a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive shaftj'a speed change mechanism connecting said shafts and'adjustable to vary the speed ratio be tween saidsha'fts, means resp'onsiveto variations in speed'of said power shaft for adjusting said mechanism to compensate for' such variations, and means responsive to changes in'the pressure of air delivered by said compresssor for also controlling the adjustment of said mechanism.

3. In combination, an; air compressor comprising a rotatable "drive" shaft, a variable speed rotatable power shaft for turning said drive shaft, a spted change mechanism connecting said shafts -and-adjustable to vary the speed ratio betweensaid shafts, and means controlled jointly by the pressure of airdelivered by said compressor andtheispeed of rotation of said power shaft for adjusting said mechanism to compensate for variations in speed-of said power shaft and; for also ad usting said mechanism to increase; the speed of said compressor drive shaft upon a decrease inthe pressure ofxair delivered by said compressor and 'to' decreasethe speed of said'compressor drive shaft upon an increase in thepressureof air delivered by said compressor;

4; In combination, an-air compressor comprising a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive'shaft, a' speed" change mechanism connecting said shafts andadjustable to vary the speed'ratio between the shafts, and means for controlling the adjustment of said 'mechanlism including speed governor means responsive to variations in speed of said power shaftto adjust said mechanisni' to compensate for such variations in speed, and pressure sensitive means controlled by the'pressure of air delivered by said compressor and operative to' adjust said'mechanism'to increase the speed of said compressor drive shaft upon a reductioninsaid air pressure and to decrease the speed of said compressor driveshaft upon an'increase in the degree of said air'comp-ressor. V

5. In combination, an air compressor'comprising a rotatable drive shaft, a variable speed r tatable power shaft for'turnirig said drive shaft, a driven friction disk secured to the said compressor drive shaft, a driving friction disk secured to said power shaft for rotation therewith and cooperative with said driven diskto turn said drive shaft for operating said compressor, one of said disks being movable radially relative to the other to vary the'sp'e'ed ratio between said disks, and means controlled jointly by the speed of said power shaftl'and the'pr'es'sure of air delivered by said' compressor 'for controllingthe position of the one disk radially of the other disk.

6. In combination, an airco m pressor comprising a rotatable drive shaft, a'variable'speed ro tatablepower shaft for turning said drive shaft,v

a driven friction disk securedto said compressor drive shaft, a driving friction disk secured to said power shaft for rotation therewith and cooperative with said driven disk to turn said drive shaft for operating said compressor, one of said disks being movable radially relative to the other to vary the speed ratio between said disks, a speed governor device responsive to variations in speed of said power shaft for moving said one disk relative to the other to compensate for such variations in speed, and means responsive to the pressure of airdelivered by said compressor for modifying the response of said governor device to the speed of said power shaft for increasing thespeed of said compressor drive shaft upon a reduction in the pressureof air delivered by said compressor and for reducing the speed of said compressor drive shaft upon an increase in said air pressure.

'7. In combination, an air compressor comprising a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive shaft, a speed change mechanism connecting said shafts and adjustable to vary the speed ratio of said shafts, a spring, a speed governor device connected to operate with said power shaft and controlled by the opposing forces of said spring and centrifugal force for operating said mechanism to compensate for variations in speed of said power shaft, and means for varying the action of said spring on said governor device for operating said governor device to adjust said mechanism to vary said speed ratio. a

ing a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive shaft, a speed change mechanismconnecting said shafts and adjustable to vary the'speedratio of said shafts, a spring, a speed governor device connected'to operate with said power shaft and controlledbythe opposing forces of said spring and centrifugal :force for operating said mechanism to compensate for variations in speed of said power shaft, and means responsive tovariations in the pressure of air delivered by saidcompressor to vary the action'of saidspring on said governor device for thereby operating said governor device to adjust said mechanism to vary said speed ratio;

"9. Inbombination, an air compressor com prising a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive shaft, a speed change mechanism connecting said shafts and adjustable to vary the speed ratio of said shafts, a spring, a speed governordevice connected to operate with said power shaft'and .controlled by the opposing forces of said spring and centrifugal force for operating said mechanism to compensate for variations in speed of said power shaft, and means controlled by the pressure of air delivered by said compressor and operative to vary the action of said spring on said governor device for thereby effecting operation of said mechanismto increase and decrease the speed of said'compressor drive shaft upon a reduction and an increase, respectively, in said air pressure.

10. In combination, an'air compressor comprising a rotatable drive shaft, a variable speed rotatable power shaft for turning said drive shaft, a speed change mechanism connecting said shafts and'adjustable to vary the speed ratio off'said shafts, a spring, a speed governor device connected to operate with said power shaft'and controlled by the opposing forces of said spring and centrifugal force for operating said mechanismto compensate for variations in speed of said power shaft, a nut acting on said spring and adjustable axially for varying the action of said i spring on said governor device, and means controlledby' the pressure of air delivered by said compressor and operative upon an increase in said air pressure to actuate said nut to reduce the aotionof said spring on said governor device and upon a reduction in said air pressure to increase the action of said spring on said governor for thereby effecting operation of said mechanism to increase and decrease the speed of said compressor'drive shaft upon a reduction and an increase, respectively, in the pressure of air delivered by said compressor.

1'1. In'comb-ination, an air compressor comprising a rotatable drive shaft, a variable speed rotatable power shaft, a driven friction disk secured to said drive shaft for turning same, a driving friction disk secured to said power shaft for rotation therewith and cooperative with said driven disk to turn said drive shaft for operating said compressor, one of said disks being movable radially relative to the other to vary the speed ratio between said disks, a spring, a speed governor device connected to rotate with said power shaft and connected to said one disk, said speed governor device being controlled by the opposing pressures of said spring and centrifugal force and being operative in accordance with variations in speed of said power shaft to vary the radial position of said one disk with respect to --the other to compensate for such variations in speed, an axially movably nut backing up said spring for controlling said governor device, and means controlled by the pressure of air delivered by the compressor and connected to said nut and operative upon a reduction in said air pressure to turn said nut in a direction to relieve the action of said spring on said governor device and upon an increase in said air pressure to turn said nut in the opposite direction to'increase the actionof said spring on said governor device for thereby varying the speed ratio betweensaid disks inversely according to the pressure of air delivered by said compressor.

' 12. In combination, an air compressor, a driven friction disk for operating said compressor, a prime mover, a driving friction disk rotatable by said prime mover and having a peripheral face frictionally engaging an end face of said driven disk for driving said compressor, a spring, a speed governor device connected to rotate with said driving disk and subject to the opposing forces of said spring and centrifugal force and operative in accordance with variations in the rotative speed of said driving disk to move said driving disk radially of said driven disk to compensatefor such variations, an axially movable nut backing up said spring, and means for actuating said nut to vary the action of said spring on said governor for thereby varying the speed of said driven disk.

13. In combination, an air compressor, a driven friction disk operable upon rotation to operate said compressor, a prime mover, a shaft spaced from one end of said disk and disposed at right angles to the axis thereof and secured to rotate with said prime mover, a sleeve slidably mounted on said shaft lengthwise thereof, a frictiondisk secured to rotate with said shaft and movable with said sleeve radially of said driven disk and having a peripheral face in frictional driving engagement with the end face of said driven'di'sk, a governor control spring acting on said sleeve for opposing movement of said driving disk in the direction of the perimeter of said driven disk,'a

speed governor device rotatable by said shaft and connected to said sleeve controlled by the oppos ing forces of said spring on said sleeve and centrifugal force for moving said driving disk rad-iof air delivered by said compressor and icon-;

nected to said governor spring for varying the action thereof on said governor device,"said piston being operative when said air pressure eX- ceeds the pressure of the second named spring to change the action of the governor spring on said governor device so as to shift said driving disk inwardly of said driven disk for increasing the speed of said compressor and being operative when the pressure of fluid acting on said piston exceeds the opposing pressure of said second named spring for relieving the action of said governor spring on said governor device for thereby rendering the governor device operative to move said driving disk outwardly of said driven disk to thereby reduce the speed of said compressor.

14. In combination, an air compressor, a driven friction disk operable upon rotation to operate said compressor, a prime mover, a shaft spaced from one end of said disk and disposed at right angles to the axis thereof and secured to rotate with said prime mover, a sleeve slidably mounted on said shaft lengthwise thereof, a friction disk ecured to rotate with said shaft ass ss and movable with said sleeve radially of said driven disk and having a p'eripheralface in frictional driving engagement with the'end face of said driven disk, a governor control spring acting on said sleeve for opposing movement of said driving disk in the direction of th perimeter of said driven disk, 2. peed governor device rotatable by said shaft and connectedt'o' said sleeve controlled by the opposing forces of said spring on said "sleeve and centrifugal force for moving said driving disk radially of said driven disk to pos tions to compensate for variations in speed of said prime mover, an axially adjustable nut backing up said governor spring and operative upon rotation to vary the actionof said spring on said governor, a gear secured to said a nut for turning same, a gear rack formats/ting said gear, a second spring, a piston connected to said rack and subject to the opposing pressures of said second spring and of air delivered bysaid compressor, said piston being operative when the pressure of said second spring exceeds that of the air delivered by the said compressor to actuate said gear and nut to change the action of said governor spring on said governor device for thereby rendering said governor device operative to move said driving disk inwardly of said driven disk to increase the speed of said compressor, said piston being operative by the pressure of air delivered *by'saicl compressor when said air pressure exceeds that of the second named-spring to actuate said gear and'nut for relieving the action of said governor spring on said governor device to thereby render "said governor device effective to 'move said driving disk outwardly of said driven disk to reduce the speed of said compressor.

15. In combination, an air compressor, a driven friction diskoperable upon rotation to oper-.

atef said compressor, a prime mover, a shaft spaced'from-one end of saidydisk and disposed atright angles to the axis thereof and secured to rotate with said primemover, a sleeve mounted to slide on said shaft in thedirection of its length and secured to rotate with said shaft, a

friction driving disk having a peripheralfriction,

face in frictional driving engagement with an end face of said driven disk, said driving disk being secured to turn with said sleeve'and' being movable radially of said end face upon movement of said sleeve lengthwise of said shaft for varying the speed ratio between said disks, a speed governor deviceoperative in accordance with the speed of rotation of said prime mover for mov-- ing said sleeve on'said shaft and for thereby mov ing said driving disk relative to said driven disk to-vary the speed ratio between said disks to compensate for variations in speed of said prime mover, and means responsive to changes in the pressure of air delivered by said compressor to vary the operation of said governor-device for varying said speed ratio to vary the speed of said compressor inversely to the pressure of air being delivered by said compressor. 7

- 16'; In combination, an air compressor, a driven frlction disk operable upon rotation to operate said compressor, a prime mover, a shaft spaced from one end of said disk and disposed at right angles to the axis thereof and secured to rotate with said prime mover, a sleeve mounted to slide 'on said shaft in the direction of its length and said driven disk, said driving disk being secured to turn with said sleeve and being movable radially of said end face upon movement of said sleeve lengthwise of said shaft for varying the speed ratio between said disks, a second sleeve secured against axial movement and having a telescopic connection with the first sleeve and secured for rotation therewith, a spring extending through said second sleeve and acting on said first sleeve urging same and thereby said driving disk in the direction of the center of said driven disk, a speed governor device operatively connected to said sleeves and rotatable therewith, said speed governor device being controlled by .10 speed ratio between said disks upon a reduction in air pressure and increase said speed ratio upon an increase in air pressure.

' ELLIS E. HEWITT.

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