US2402400A - Regulating device - Google Patents

Description

june 18, 1946. E- E HEWlTT ET. AL 2,402,400

' REGULATING DEVICE Filed Dec. 31, 1942 IVENTORS ELLIS E HEwrr-r BVROBERT :.WA'rsoN ATTORN EY Patented June 18, 1946 REGULTING DEVCE Ellis E. Hewitt, Edgewood, and Robert E. Watson, Swissvale, Pa., assignors to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application December 3l,1942, Serial No. 470,804

V11 Claims. i

This invention relates to regulating devices and more particularly to means for opposing movement and for 4defining different positions of a power operated member.

In the copending application of Roy R. Stevens, Serial No. ld3,'792, iiled October 29, 1942, -now Patent No. 2,383,278, of August 2l, 1945, there is disclosed a fluid motor embodying a power piston, a pilot piston, and valve means operable by the pilot piston uponmovement relativev to the power piston to establish a differential in fluid pressures on opposite sides of the power Vpiston for eiecting movement thereof. The power piston in turn is operable upon movement relative to the pilot piston to actuate the valve means 'to eeot equalization of the fluid pressures on opposite sides of the power piston for stopping same in a position corresponding to that of the pilot piston. The power piston. has aneutral position and at either side of such position has three other positions. The pilot piston has like positions, and a regulating device embodying a plurality of springs conned under pressure is arranged to become effective or ineffective in certain of these diiferent positions'for opposing pressure of uid on the pilot piston and to define such positions. In other words, a certain pressure of fluid provided on the pilot piston will cause a chosen positioning thereof determined by one of the springs while a diierent pressure of uid on the pilot piston will cause a diierent chosen positioning thereof determined by another spring, whereby the power piston may be caused to as-I -surne any cho-sen position by providing the required chosen degree of fluid pressure on the pilot piston.

The principal object of the present invention is the provision of an improved regulating device-r spring arrangement for opposing movement and for dening different positions of a member, such as the pilot piston above described.

Other objects and advantages will be apparent from the following more detailed description oi' the invention. y

vIn the accompanying drawing the single ligure is a sectional view 0f a portion Voi a control apparatus embodying the improved regulating device. l

Description In the-drawing, the reference numeral i indi cates the improved regulating device, and the reference numeral 2 indicates a lever which is mounted to turn on a fulcrum pin .2a which is fixed with respect to said device.

The lever 2 may have a "neutral position in which it is shown and `ateither side ofsaid positiona plurality of other positions such-as indicated by doty and dash linesV designated by legends A, 13, .and C at one side of .the neutral positiomand legends A, B-, andy C, at the opposite side of the neutral position.

An actuating member 3 is connected by apin li to the lever 2 for moving said lever to its different positions, and vactuating force-may be applied to this member by'pressure of iiuid on a pilot piston such as above described but which is not shown in the drawing since it is not essentialigc an understanding of the invention.

'flie regulating device I .comprises a tubular casing open at opposite en ds and substantially axially aligned with the free end of lever 2 when in fneutral position. .This casing is provided interiorly with a laterally extending annular Ywall 5 located substantially midway between one Vend and the center of thecasing, while occupying a substantially like position adjacent the opposite end of the casing is an adjustable nut 6 having screw-.threaded engagement interiorly with the casing. The outer end of this nut is provided with screw-threaded engagement 'with the casing .is

provided for entering one oranother of the slots 8 for securing said nut in an adjusted position.

Two oppositely arranged and axially aligned thimble-like elements 9 and iil-aredisposed in theV casing between the wall 5 and nut 6 with their smaller ends adjacenteachother and their larger and opposite ends arranged for engagement with the adjacent faces of said wall and nut, respectively. A coil spring Il encircling the two elements 8 and lil bears at one end against Athe element il and at the opposite end against the element lil. This spring is vcompressedto acertain degree by proper adjustment of nut 6 inthe casing therefore acts to urge the elements i? and i@ apart and into engagement with walll 5 and nut B, and to oppose movement Vof either of said elements .relative .to -the other yout of engagement with said wall or nut, respectively. A sleeve l2 is mounted to slide inan axial bore provided through the smaller end of element 9 and is provided within said element with an annular collar i3 between which and the portion of said element encircling the sleeve is interposed vone or more adjusting shims I4. A like and oppositely disposed sleeve l5 is slidably mounted in an axial bore through the smaller end of element I9 and is provided within said element with an annular collar I3 between which and the portion of said element encircling said sleeve is interposed one or more shims I1. The shims I4 and I'I are of such thickness as to allow the sleeves I2 and I5 to extend substantially the same distance beyond the adjacent ends of the respective elements 9 and I9, and .to also obtain a distance between the adjacent ends of said sleeves with said elements in contact with the collar 5 and nut 6, respectively, which corresponds to the distance between the positions indicated by the legends A and B, and A and B at the point of connection between the lever 2 and the regulating device, which will be later described.

In the end of the casing adjacent wall 5 there is a ring-like adjusting nut I 9 having screw-threaded engagement with the casing and provided in its outer face with slotsI 2|] for receiving a wrench to adjust the nut. A lock screw 2| having screwthreaded engagement in the casing in alignment with the periphery of n ut I9 is provided for turning into contactwith said nut to secure same in an adjusted position. An oppositely arranged and like nut 22 is provided in the opposite end of the casing and has screw-threaded engagement interiorly thereof. This nut in its outer end is provided with slots 23 for receiving a wrench to adjust the nut in the casing. A set screw 24 having screw-threaded engagement with the cas- 'ing in alignment with the periphery of nut 22 is provided for engagement with said nut to secure same in an adjusted position.

Between the wall 5 and nut I9 is a circular stop element 25 which isrconsiderably smaller in diameter than the central opening through wall 5 so as to be capable of movement therethrough without contacting said wall. One end of the stop element 25 is arranged for contact with the adjacent face of nut I9, while the opposite end is arranged for engagement with an annular portion of the thimble-like element 9 which extends inwardly of the wall 5. A coil spring 26 bears at one end against the collar I3 of sleeve I2 and at the opposite end against the stop element 25 through the medium of one or more adjusting shims 21. The stop element 25 is assembled in position before applying the nut I9 to the casing and then said nut is adjusted to move said element in the direction of the thimble-like element 9 to a position in which the space between the two elements with the elementJ 9 in contact with wall 5 equals the distance between the positions indicated by the legends Neutral and A at the point of connection between lever 2 and the regulating device, which connection will be later described. The number or thickness of shims 2'! between the stop element 25 and spring 26 is such as to provide a certain chosen pressure of spring 26 on the element 25 and sleeve I 2 when said element is adjusted by nut I9 to this relation with the thimble-like element 9.

A stop element 29, like the element 25, is interposed in the space between the adjacent ends of the thimble-like element I and nut 22 and is freely movable through the central opening in nut 6. One end of the element 29 is arranged for engagement with Ythe adjacent end of nut 22 while the opposite end is arranged for engagement with the adjacent end of the thimble-like element I IJ over the portion of said element which extends within the nut 6. A coil spring 30 bears at one end against collar I6 on sleeve I5 and at the opposite end against the adjacent face of stop element 29 through the medium of one or more shims 28.

The stop element 29 is assembled in the casing before applying the nut 22 and then said nut is adjusted for moving said element inwardly of the casing to a position in which the space between said element and thimble-like element I0 when in engagement with nut 5, equals the distance between the positions of lever 2 indicated by the legends Neutral and A at the point of connection between said lever and the regulating device which connection will be later described. The shims 2B are such that in this adjusted position of the stop element 29 the spring 3.0 will be so compressed as to exert a chosen degree of force against said stop element and sleeve I5.

In order to insure centering the thimble-like elements 9 and |9 and stop elements 25 and 29 with respect to the casing and to each other the cooperating surfaces on said elements and on the wall 5 and nuts 6, I9, and 22, respectively, are beveled or formed at an acute angle to the axis of the casing. Further, each two of the cooperating surfaces are formed differently so as to provide only a line contact between the surfaces in order to reduce to a minimum the reluctance to separation of the parts on which the surfaces are formed. Preferably the surfaces on the stationary parts constituting the wall 5 and nuts 6, I9, and 22 are provided within such parts in the form of straight, line bevels, While the cooperating surfaces on the movable elements 9, I0, 25, and 29 are arcuate in form. For 4,the same reasons, the surfaces on the thirnble-likeelements 9 and I9 provided for engagement by the stop elements 25 and 29 are within the elements and in the form of straight line bevels while the cooperating surfaces on the elements 25 and 29 are arcuate in form.

A rod 3| loosely extends through axial openings provided in the stop members 25 and 29 and in sleeves I2 and I5 and has one end adjustably connected by screw-threads to one end of a link 32. The opposite end of link 32 is pivotally connected by a pin 33 to the free end of lever 2, this connection between rod 3| and lever 2 constituting the point of connection between said lever Vand the regulating device I, hereinbefore mentioned. A lock nut 33a on the rod 3| is provided for engagement with the link 32 for securing said rod in an adjusted condition with respect to said link.

The stop member 25 has axially an annular cavity open at the outer end of said member and connected at its inner end to the larger end of a frusto-conical recess. A follower 35 is disposed in this cavity and has a nose portion disposed in lthe frusto-conical recess wherein it engages the stop member 25. The diameter of the follower 34 is less than the diameter of the cavity in the stop member 25 in order to allow centering of said follower with respect to said stop member when in contact therewith due to the cooperative action of the tapered engaging surfaces which may be formed like the cooperating centering surfaces heretofore described in connection with other parts of the device, or if desired, both of said surfaces may be formed at the same angle. When the follower 35 is disengaged from the stop element 25, said follower being of smaller diameter than the cavity in said element, provides for a certain free radial movement of the follower relative to said element.

The stop member 29 has axially a cavity open at the outer end oi the .member :and an ,inner frusto=conical recessv likegin the stop Vmerroier 25. and :disposed int-his cavity andrecessiis iaizfollower "3,6,like the follower 35'but oppositelydlsposed. The cooperating surfaces lon the follower 36. and element 2.9 are provided for centering said follower with `respect to said element, and with said-follower disengaged from said element said follower has a certain free radial movement relative to saidelement.

'The rod 3| also extends through the followers 35 `and 35' but not'loosely asin the stop elements 25 :and 29 and in thesleeves I2 and I5. A nut 31 isrprovided onthe rod 3| vfor contact with the follower 35 to hold same against movement von the rod inthe direction of lever 2, whilea look nut 38 is also provided on said rod for engagement with the nut 31 to secure same'in an ad` justed position. A castle nut 39 is provided on the end of rod 3| and engages the 'follower 36,

moving asamenut ofcontact with the adjusting nutt:.i. VThedierencein force zrequired to move the stop element 29 into contactfwith Vthe thimsaid nutbeing secured against turning on the rod by a cotter key 40.

With the two nuts I9 and 22 adjusted'as before described and with the stop elements and 29 in engagement with said nuts, the nut 31 is `a'djusted on the rod 3| to urge the two followers 35 and 35 into contact with said stop `elements and then the lock nut 3l!V is adjusted for secury ing the nut 31 against' movement. With the parts of the regulating device in theiradjustedcondition above described and shown in the drawing, the link 32 on the end of rod 3| is then adjusted relative to said rod for connection with the lever 2 by pin 33 with the lever in its neutral position shown. The pin 33 is then applied to link 32 and' lever .2 thereby connecting the regulatingdevice I to said lever.

Operation With `the parts of the regulating device I `in the condition shown in the drawing and above described, it will be notedthat the force of-sprlng II will urge the thimble-.like elements 9 vand I0 into contact with the wall 5 and adjusting nut 6 respectively while the pressure of springs .2 6 and 3G will urge the stop elements 25 and 29 into contact with the adjusting nuts |.9 and 22 respectively, for thereby actuating the rod 13| and link 32 to position the lever 2 in its "neutral position shown.

Now let it be assumedthat itis desired to. move the lever 2from its neutral" .position in the div rection Yof the right-hand- Io accomplish .this end force is applied throughrod 3, to lever 2 and thence through rod 3| to the ,follower V36 and stop element `23. When this Lforce is vin creased sufficiently to overcome thepressureof spring V on element ,28, said spring will yield to permit, movement of lever 2 asdesired and said element will be pulled out of Contact with the xed stop or adjusting nut 272. As the ,force applied to the lever 2 then continuestoinorease said lever will continue tov move against theincreasing force of spring 33 until the stop element 29. engages :the thimble-like element t0 whichl is subjecttothe preoompressed force of spring and which condition will be obtained at thetime the lever 2 attains the position indicated by the legend A. A certainY deiinite forceV .governed by spring 3B is thus reduit-eden Vthe lever Y2 l:.for

moving said lever from neutralposition tothe position A,and when thislatter position Ais attained, a definite increase in force `on `lever 2 vis Y required to overcome the precompressed- -force of spring I,I on the thimblelike-element I0. for

ble-Ylikecelement IB and to then-move lsaid-ele ment against spring .YI I constitutes a `range of force which-may :be applied through thev rod v3 for mcvingithe-leverzito the position .A. `.The application Yoi" 4anvrdegree :of ,forcerwithin this range to the rodr I will 4,tliercfore insure movementtofthe lever .2 tor-the. position .AJ

Letfitnowbe assumed that-it isrdesired totmove leverf2 :to :the position in'dicate'd bythe .legend 13; 'Ifo accomplish this end the "force :applied to :theilever throughrodi-is'increased to agdegree sufficient to. overcome the foppcsing .fierce :of spring f'II' following-which said spring will Yyield to ,permit movement off saidilever; andsuchmovement willicontinue as the force applied' to thezrod 3 is1increaseduntilthe end; ofrs'lieeve-v 5. moves Vinto contact with Vsleeve I2 `which defines dthexposition B.v Eurthermovemerit-ofthe lever-Ziwillthen be 'opposed by the pressure of spring F26 on the Asleeve I2, it being notedthat at this'instant-the pressure of spring Z-Iii's` less than that Vof Aspring 30 which was compressed vduring the initial'move ment Vof lever2f out 'o.f"neutral position. A certain. degree of forceis thus required on lever 2te move the. sleeve f5 'into contact with the sleeve I2, andadeniteeincrease in 'this forceis ithen requiredto Yovercome the vprecompressed force of spring 26,the difference betweensuch forcesconstitutingxarange of 'force which maytbe'iapplied to the .lei/'e112'v for 'obtaining contact between vthe vsleeves* |Y and I.2".w`nichy den'es .the position B of lever 2. It will thus be seen 'that if'a forceis appliedto. leverZ4 through rodf3 of-a degreeanywhere-within 'said vlatter frange, :a `positive:positioning fof the lever21infthe .position B\`will. be

attained. f

VIngorder to now .move theilever 2,from position B andffCi. the force `applied through rod3 totheclever must beincreased'to a degree-sufficient 'to 'overcome the 'forcesof'spring Ifl in addition fto the force oixspringjZii and `when this 'force condition is4 obtained, :the vIever Y2: will move to 'the position indicated'bvthe legend C, this :position fin the specicA 'embodiment of :the invention vshown in the drawing being dened "by meansfother than int/the regulatingfdevice IY and therefore not shown-inthe drawing.

Now let lit be assumed that with the lever 2 in position C itis desired to move said leverback to 'position 5 "To .do vtlfiisthe'force applied through rod"3 itc 'lever 2 is reduced to a value .within the range required :to 'effect' movement of sleeve .LEinto contact with sleeve I2 `but insuf- -icientfior'r'novingI sleeve I2V inwardly of the thimfble-likeelement v'As a result of this reduction in force on lever 2 thercombinediorce of'spring's tion B to position A, 'the -force on lever `2 isagain reduced to a value within the range required :for moving the stop element 29 into contactwith the thimble-'like element I'l but insuf cient'for'moving the flatter against, 'spring II', Asia-'consequence the spring I I will therefore return thev th-imble-like element l0 into contact with the adjusting nut 6 while the stop element 29 will be retainedinf contact with said thimblelike `element bv the f orce'still applied .toy lever In lorder to vthen move the 'lever 2 fromposn A 7 2. v'Thus the lever 2 will be returned from the position B to the position "A and bestopped in the latter position.

To now return the lever 2 from position A to its neutralposition, all force is removed from rod 3 and lever 2 and as a result Vspring 30 will urge the stop element 29 into contact with its fixed stop or the adjusting nut 22 which defines the neutral position of the lever 2.

It will thus be seen that the stop element 29, spring 30, thimble-like element I0, spring II, sleeves I5 and I2, andspring 26 are effective at different times to positively deiine the different positions of lever 2 to the right of and including neutral position in accordance with the lack of force in rod 3 or in the application of force within two specic ranges or in the application of `a certain maximum degree of force to said rod.

When the stop element 29 is moved out of contact'with stop or nut 22 upon movement of rod3I in one direction or out of contact with the thimble-like element I0 upon movement of said rod in the opposite direction, the stop element 29 is capable of certain free radial movement within the nut 6, while at the same time the rod 3| is also free for radial movement in the sleeves I5 and I2 and stop element 25 since the follower 35 is free for movement outwardly of the stop element as maiT occur with rod 3|. The rod 3| is fixed at one end to lever 2, but its opposite end and the stop element 29 are thus in a free floating condition on the end of spring 3|] which permits adjustment of said rod to said spring in case the spring is slightly deformed, but of greater importance, it should be noted that there is' no friction between parts to interfere with spring 30 accurately determining the positionA of lever 2 according to the force applied through rod 3 to said lever. This same free condition also exists when the thimble-like element I0 is disengaged from stop 6 and with the sleeves I5 and I2 also disengaged to thereby render the position of lever adjustable by spring II with extreme accuracy in accordancel with Vthe force applied by rod 3 to lever 2. Such accuracy of adjustment is required i in the use of the device only between neutral `position and position B, and is not required between the positions B and C, and this permits the use of sleeve I2 having sliding contact with the thimble-like element 9 during movement of the lever 2 from the position B to the position 0.

VWhen the lever 2 is rocked, the connectedend of rod 3| will shift to a slight extent radially of said rod and thereby tend to move said rod slightly out of axial alignment with the regulating device, but this will in no watr aiect the-accuracy of adjustment of the lever, due to the freedom for radial movement of the rod 3| and of the stop elements 29 and ID within the casing, as above described. In other Words, this iioating character of the rod 3| and stops 29 and 0 within the regulating device as above described provides for automatic adjustmentrof the rod-3| to the lever 2 for diiierent angular positions which said lever may assume.

Upon movement of the lever in a counterclockwise direction by force applied to rod 3, stop element 25 is initially moved against the spring 25 into contact with the thimble-like element 9 for deiining the position A. The tl'iimble-like element 9 may then be moved against spring I E until the sleeve I2 contacts sleeve I5 which denes the position B', following which the stop elements 25 and 9Y may continue movement together against the combined forces of spring II and spring 30 to the position C. Upon proper reductions in force applied through rod 3 to lever 2, the lever may be returned from position C' to the position B', position A' or neutral as determined by the degree of force acting on the lever 2. In other words, this operation is identical to that described in detail in connection with movement of the lever 2 to positions at the right hand side of "neutraP position, the stop elements 25 and 9 and sleeve I2 and the springs 26,II and 30 functioning in the identical manner. Also during this latter operation the stop element 25 is free for radial movement when disengaged from the stop member I9 and thimblelike element 9, While said thimble-like element is also free for radial movement when disengaged from the wall 5 and since the rod 3| is capable of a certain limited free radial movement with-- in the sleeve I5 and the stop element 29'under these conditions the same oating condition of the rod 3 I and of the operating stop element within the casing is obtained as previously described, in order to provide accuracy of adjustment of the position of lever 2 in accordance with the opposing pressure of the controlling spring or springs A more detailed description of the operation of these parts upon movement of the lever 2 in a counterclockwise direction from neutral position is not believed necessary herein since the operation is identical to the operation upon movement of lever 2 in a clockwise direction and above described.

Summary It will now be seen that I have provided a multi-spring regula-ting device which is operative with extreme accurac37 to oppose movement of an operating member and to dene positions of said member corresponding to chosen degrees of operating force applied to the member. During operation of the movable position defining stops and the means connecting same to the operating member, such stops and means have connections only with said member, and the respective control spring is thus in a free flowing condition and independent of any other force so that the control spring may determine with a maximum degree of accuracy the position of said member corresponding to the actuating force applied to the member, and regardless of angular changes in the position of said member with respect to the axis of the regulating device, The movable position deiining means are also self-centering with respect to each other and the casing, this result being. obtained by use of tapered or beveled surfaces on they cooperating parts. These beveled surfaces are also formed to provide only line contacts between the cooperating parts so as to reduce to a minimum the reluctance to separation of the parts in order that such separation may occur upon a slight change in control force on the operating member and thus provide the desired sensitivity of the structure and accuracy of control.

Having now described our invention what we claim as new and desire to secure by Letters Patent is:

1. In combination, a member movable by force, a coil spring, a movable stop engaging one end of said spring, support means carrying the opposite end of saidV spring and arranged to be engaged by said movable stop for limiting compression of said spring, stop means arranged for engagement by said movable stop to limit expansion of said spring, one of said means having an 9., axial opening, a rodv of; smaller diameter than saidr opening extendingv therethrough,y the surfaces; of said movable stopv and of said support means: and stop means which are provided for engagement being generally frusto-conical in shape for cooperation to centralize said movable stop with said openingrupon engagement of said movable stop with either said support means or said stop means, and one of each pair of cooperating surfaces being formed differently than the other to limit the surface of contact to less than the full area of the surface, means connecting` said rod to said member, and means connecting said rod to said movable stop, said movable stop and rod being movable against and byl said spring upon an increase and decrease respectively in the degree of force applied to said member, and` said movable stop and the connected end of said spring and rod being freely movable radially of said opening with said movable stop out of engagement with said stop means and support means.

2. In combination, a movable member arranged to be subjected to Van operating force for moving same, and a spring device connected to said member and cooperative therewith to define positions of said'member corresponding to the degree of said forceapplied to said member, said device comprising a casing, two coaxially arranged coil springs in said casing, a rst movable stop engaging one end of one of said springs and supporting one end of the other spring, a second movable stop engaging the opposite end of the other spring and arranged after a certain movement against the respective spring to engage said first movablestop and then move same against its spring, stop means fixed with respect to said casing andiengageable by each of said movable stops for limiting extension of the respective spring, means on said movable stops and stop means cooperative upon engagement of said movable stops with the respective stop means to centralize said movable stops with each other,

saidmovable stops being freely movable in saidv casing radially of said springs upon disengagement from said stop means, said iirst movable stop and said stop means therefore having central openings, and a rod of smallerdiameter than said openings extending therethrough and having one end connected to said second movable stop and the opposite end connected tofsaid member and operable by said member upon an increase in force thereon to successively move said movable stops against the respective springs. V3. In combination, a movable member arrange to be subjected to an operating force forV moving same, and a spring deviceconnected to said member and cooperative therewith to define positions of Said member corresponding to the degree of said force, said spring device comprising a easing having a bore, a first ring-,like xed stop associated Iwith said casing within said bore, a first circular movable stop of smaller diameter than said bore and disposed therein, a spring on said casing acting on said movable stop and operative to move said movable stop into contact-with said xed stop, a second ring-like fixed stop in said casing, a second circular movable stop of smaller diameter than said bore and disposed therein, a second spring interposed under pressure between said -first and second movable stops and operative to' urge Isaid second movablestop into contact the'. surfaces on said fixed stopsengaged by said movable stops beingy coaxial' with said bore and said 'surfaces and the cooperating contacting su-rfaces on said. movableA stops being generally frusto-conical in shape but formed dier'entlyto thereby centraline said stops in said bore andA to provide a linecontact between said fixed and movable stops, said fixed and movable stops having axially aligned openings, and a rodof smallerdiameter than said openings andtextendng through certain of said openings and having a connection with said member,r and means connecting said rod to said second movable stop for thereby rendering said springs successively effective to oppose movement of said member upon an increase in the degree of force applied thereto.

il. In combination, a movable membertarranged to be subjected to an operating force for moving same, and a spring device associated with said member andrcooperative therewith to'define vpositions of said member corresponding to the degree of said force, said device comprising a casing having a bore, two ring-like fixed stops spaced apart within said bore, a coil spring in said bore, a first movable stop in said bore of smaller diameter than said bore and subject to pressure of said'spring which is effective to move same into contact with one of said xed stops, a second movable stop ofsmaller diameter than the opening through said one xed stop and arranged to move` therethrough from a position in contact 'with the other fixed stop toa position in contact with said first movable stop, means included-in said xed and movable stops cooperative upon interengagement'to centrali'ze said movable stops in said `bore and to centralizesaid movable stops with each other upon interengagement, a sleeve slidably mounted'lin' said rst movable stop axially thereof and havingV an enlarged proportion arranged for contact with said lirst movable stop on the side adjacent said second movable stop, a spring interposed under pressure between said sleeve and second movable-stop and effective to urge said second movable stop against said other flxed stop and to yield to allow movement of said sleeve in the opposite direction, said second movable sto-p and said fixed stops having axially yaligned openings aligned with the opening in said sleeve, a rod of smaller diameter than said openings extending therethrough and having a connection with said member, and means connecting said rod-to said second movable stop for rendering said springs eifective to oppose movement of said member by force.

5. In combination, a movable member arranged to be subjected to an operating force for moving same, and a spring device associated with said member and cooperative therewith'to dene positions of said member corresponding to the degree of Ysaid force, said device comprising a casing, two fixed stops spaced apart in the said casing, av coil spring in said casing, a rst movable stop in said casing subject to pressure of said spring which is eiiective to movefsame into contact with one of said fixed stops, a second movable stop 'in said casingmovable axially through said one fixed stop from a position in said casing in contact with the other xed 'stop to a position in contact with said first movable stop, a sleeve slidably mounted in said first movable stop axially thereof and having an enlarged portion arranged for .contact therewith on the side adjacent said second movable stop, a spring interposed under pressure between said sleeve and said second movable lstop effective to urge said second movable stop against said second fixed stop and yieldable to allow movement of said sleeve inwardly of said first movable stop, said second movable stop and said first fixed Stop having axially aligned openings aligned with the opening through said sleeve, a rod loosely extending through said openings and having a connection with said member, means connecting said rod to said second movable stop for rendering said springs effective to oppose movement of said member by force, said second fixed stop being adjustable in said casing for adjusting the distance between the two movable stops when in contact with the respective fixed stops, adjusting shims interposed between the enlarged portion of said sleeve and said first movable stop for adjusting the position of said sleeve therein, and other shims interposed between the last named spring and said second movable stop for adjusting the pressure of said last named spring.

6. In combination, a member having a neutral position and movable by force out of said neutral position in either one direction or the opposite direction, and a spring device for moving said member to said neutral position and for opposing movement thereof in either direction from neutral position comprising a casing, two ring-like fixed stops in said casing, a rod connected to said member and extending through said stops and capable of free movement in said stops radially thereof, two movable stops loosely encircling said rod and disposed between said fixed stops, each fixed stop and the adjacent movable stop having generally frusto-conical nose and recess portions for interengagement to centralize the movable stop with the respective fixed stop, said movable stops being capable of free movement radially of said fixed stops upon disengagement therefrom, spring means acting on said movable stops for urging same apart into contact with the respective fixed stops and for opposing movement of Vsaid movable stops out of contact with said fixed stops, and means connecting each movable stop to said rod for movement therewith in a direction to move the respective movable stop against the spring means and providing for side movement of said rod in and relative to the other movable stop.

7. A regulating device comprising a tubular casing, four ring-like fixed stops therein spaced from each other in coaxial relation, two oppositely arranged inner movable stops of smaller diameter than the bore of said casing disposed between the two intermediate fixed stops and arranged to engage the adjacent faces thereof, a coil spring under pressure interposed between and acting on said movable stops, an outer movable stop of a diameter less than the inside diameter of the two intermediate fixed stops interposed between each of the outer xed stops and the adjacent inner movable stop and arranged to move between the respective outer xed stop and the adjacent inner movable stop for engagement therewith, a coil spring under pressure interposed between each of the outer movable stops and the adjacent inner movable stop, all of said movable stops having a central opening, a rod of smaller diameter than said centralv openings extending through the movable stops, and means connecting said rod to opposite ends of the two outer movable stops.

8.,A regulating device comprising a tubular casing, four ring-like fixed stops therein arranged in coaxial relation and spaced from each other,

two oppositely arranged inner movable stops of smaller diameter than the bore of said casing disposed between the two inner fixed stops and arranged to engage the adjacent faces thereof, a coil spring under pressure interposed between and acting on said movable stops, an outer movable stop of a diameter less than the inside diameter of the two intermediate fixed stops interposed between each of the outer fixed stops and the adjacent inner movable stop and arranged to move between the respective outer fixed stop and the adjacent inner movable stop for engagement therewith, a sleeve slidably mounted centrally in each of the inner movable stops, each of the two sleeves having on opposite ends a collar for limiting movement through the respective movable stop in the direction of each other to a position providing a chosen space between their adjacent ends with said inner movable stops in contact with the respective fixed stops, a coil spring under pressure interposed between and bearing against each of the outer movable stops and the adjacent collar, all of said movable stops having a central opening, a rod of smalle!` diameter than the central openings in said movable stops and extending therethrough, and means connecting said rod to opposite ends of the two outer movable stops.

9. A regulating device comprising a tubular casing, four ring-like fixed stops therein spaced from each other in coaxial relation, two oppositely arranged inner movable stops of smaller diameter than the bore of said casing disposed between the two intermediate fixed stops and arranged to engage the adjacent faces thereof, a coil spring under pressure interposed between and acting on said movable stops, an outer movable stop of a diameter less than the inside diameter of the two intermediate xed stops interposed between each of the outer fixed stops and the adjacent inner movable stop and arranged to move between the respective outer fixed stop and the adjacent inner movable stop for engagement therewith, a coil spring under pressure interposed between each of the outer movable stops and the adjacent inner movable stop, all of said movable stops having a central opening, a rod of smaller diameter than said central opening extending through the movable stops, and means connecting said rod to opposite ends of the two'outer movable stops, one of said fixed stops being fixed with respect to said casing, and all other fixed stops being removable from said casing and adjustable therein.

10. A regulating device comprising a tubular casing, four ring-like fixed stops therein spaced from each other in coaxial relation, two oppositely arranged inner movable stops of smaller diameter than the bore of said casing disposed between the two intermediate fixed stops and arranged to engage the adjacent faces thereof, a coil spring under 'pressure interposed between and acting on said movable stops, an outer movable stop of a diameter less than the inside diameter of the two intermediate fixed stops interposed between each of the outer fixed stops-and the adjacent inner movable stop and arranged to move between the respective outer fixed stop and the adjacent inner movable stop for engagement therewith, a coil spring under pressure interposed between each of the outer movable stops and the adjacent inner movable stop, all of said movable stops having a central opening, a rod disposed in the openings in said movable stops loosely thereof radially of said openings, and

means secured to said rod engaging opposite ends of the two outer movable stops, the surfaces of said means and outer movable stops arranged for engagement being generally frusto-conical in form for centralizing said rod with said outer movable stops. f

11. A regulating device comprising a tubular casing, four ring-like fixed stops therein spaced from each other in coaxial relation, two oppoitely arranged inner movable stops ofvysmaller diameter than the bore of said casing disposed between the two intermediate fixed stops and arranged to engage the adjacent faces thereof, a coil spring under pressure interposed between and acting on said movable stops, an outer movable stop of a diameter less than the inside diameter of the two intermediate xed stops interposed between each of the outer xed stops and the adjacent inner movable stop and arranged to move between the respective outer xed stop and the adjacent inner movable stop for engagement therewith, a coil spring under pressure interposed between each of the outer movable stops and the adjacent inner movable stop, all of said movable stops having a central opening, a rod disposed in the openings in said movable stops loosely radially of said openings, and means secured to said rod engaging the opposite ends of the two outer movable stops, the engaging portions ofA said fixed stops and movable stops be-

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