US1339939A - Power-operated reversing-gear - Google Patents

Description

J. H. ALTER.

PowER OPERATED REVERSING GEAR.

APPLICATION FILED OCT- 7, 1918.

Patented May 11, 1920.

sTATEs PATENT oEEIcE.

J'O-BN' H. ALTER, 0F CONNEAUT, OHIO.

POWER-OPERATED REVEBSING-GEAR.

Speoication of Letters Patent.

Patented May 11, 1920.

Application illed October 7, 1.918. Serial No. 257,139. 4

` guided. According to present day practice,

the link-motion of the one or rudder of the other is adjusted by Huid-pressure operating upon a piston contained in a cylinder, the iow of pressure fluid being controlled by means of suitable valve devices which are under the joint control of the engine driver (or steersman) and of the piston itself, the operation being that the englne driver (or steersman) displaces the valve devices so as to admit iuid to move the piston in the desired direction, which movement itself restores the valve devices to closed position when the piston has reached the location desired by the driver (or steersman). I have discovered that, owing to the joint control of this valve mechanism, any

-looseness in such mechanism and particularly in the joints thereof renders the piston movement entirely out of proportion to the engine manual adjustments, and also causes the piston, instead of remaining quiet at any one position, to perform a continuous reciprocation (technically known asA creeping) between the limits fixed by this looseness. The present invention provides a remedy for both these defects regardless whether the looseness arises from wear or inaccurate workmanship.

Accordingly it is the general object of this invention to provide expedients for cutting down so-called piston creeping, -for reducing valve looseness, and generally for reducing the tendency of the device to depart from the adjustment imposed upon. the same by the engine driver. Other objects of the invention are the provision of improvements of the general nature stated which can be installed upon or applied to existing devices with a minimum of diiiiat I, JOHN H. ALTERLa culty and expense; while further objects and advantages of the invention will become apparent as the description proceeds.

n the drawing accompanyin and forming a part of this application Ihave illustrated my improvements as applied to oneof the many reversing-gear devices now known and in use, although it will be understood that my improvements are not limited to use with this particular gear and that I am not restricted to the particular constructions and arrangements herein delineated, since my drawings, are intended to be merely illustrative of the principles of my invention. In this drawing Figure 1 is a side view of a locomotive showing a standard type of reversing gear and a standard type of link-motion; Fig. 2 is an enlarged detail view of the reversing-gear illustrated in Fig. 1 illustrating my improvements and their mode of coperation therewith; Fig. 3 is a partial view illustrating certain modiications of my invention; and Fig. 4 is a detail view showing other modifications of my invention.

Describing the parts by reference characters 1 represents generally the link-motion of a locomotive, the well known Stevenson link being here shown for purposes of illustration because of its simplicity but without intent to limit the invention to that type. Suitably articulated to this link-motion is an operating lever 2, here shown as of the lifting arm type, by means of which the link-motion parts are supported and their relative positions varied. 3 represents a cylinder carried by the side of the locomotive in a horizontal position and having a piston 4 connected to a piston rod 5, attached to a cross head 6 which in turn is connected by the drag link 7 to the lever 2. At one side of the cylinder 3 usually the top side is located the va'lve box 8 having therein a slide valve 9 connected to the stem 10 projecting through a stuiing box 11 and having its outer end pivoted at 12 to the l'ever 13 Whose opposite end is articulated at 1li-.to a connecting link '15 attached to the cross head 6. Also articulated to the lever 13 is a second link 16 pivoted at l17 to a lever 18 fulcrumed at 19; and to the lever 18 is articulated the reach rod 20 which extends into the cab and is there attached to the hand lever 21 by which it may be adjusted, said hand lever 'having a toothed sector 22 by which it may be locked in position.

' is suiciently The side of the valve box 8 is connected to the opposite end of the cylinder 3 by ports 25-26 arranged as in .conventional steamengine parts; and betweenv said ports is located an outlet port 27. The slide valve is ordinarily made with only a small amount of lap, either outside or inside. Supposing the lever 21 to be moved rearwardly and locked to its sector; the reach rod 20 is thereby moved forwardly rocking the lever 18, retracting thelink 16, moving the upper end of the lever 13 toward the rear 'and carrying with it the slide valve 9 so as first to place the port 26 in communication with the slide box interior and also, if the movement great placing the port 25 in communication with the exhaust 27. The piston 4 is immediately moved rearwardly by the fluid pressure raising the link-motion parts 1 and shifting the cross-head 6 toward the left. This movement of the cross-head carries with it the lower end of the lever 13 and thus produces a forward movement of the slide valve, the link 16 being held against movement by the sector 22. This movement of the piston continues until the valve 9 has been advanced suiciently to cover the port 26, when it stops; the fluid pressure in the forward end of the cylinder being generally greater than that in the rearward end of the cylinder owing to the weight of the parts 1 necessarily supported by that pressure. The

valve 9 is therefore ordinarily retained in central position, the lever 21 serving to displace the same toone side or the other depending upon the desired movement of the link-motion, and the piston serving to restore the valve to central position when such movement has been accomplished.

Supposing however that a small leak exists, for example from the forward end of the cylinder, the decreasing pressure will permit the 'piston to move forward until the valve has been displaced suiciently to admit more Huid pressure, and in any case material looseness existsin one of the numerous pivots of the controlling mechanism, a very considerable movement of the piston may thus be permitted before the lost motion is taken up sufficiently to operate the valve; and after the valve has thus been opened to permit the entrance of fluid pressure, thel same looseness inA the joints will prevent the closing of the v alve so as to shut off that pressure until the piston has progressed equally far in the other direction. For example the proportions of the lever 21 are not infrequently such that a movement ofl the same of 1th inch along its sector corresponds to amovement of the reach rod 20 of lgth inch and a movement of the piston 4 of two inches. The movement of the link 16 under these conditions might easily be not more than @15nd inch, while a combined play of all the various joints in the apparatus aggregating @nd inch is not at all unusual, to which must be added the looseness of fit of the lever detent in the sector 22. Under such conditions it is impossible to adjust the position of the piston 4 within less than two inches, which is sulicient to make a decided effect upon the operation of a locomotive, and the slightest leakage in the cylinder will produce an alternate creeping back and forth of said piston within the limits permitted gy this looseness of the valve mechanism.

his not only causes a continuous variation in the engine operation, but promptly wears out the cylinder at the particular region where the maximum running occurs, thereby increasing the leakage tendency, thereby increasing the creeping, which again increases the wear until the device becomes very unreliable.

In order to overcome this tendency I provide the valve with yielding devices, independent of the various connections, and tending always to move the same in one direction or the other so as to take up all looseness of the joints throughout the control system. This yielding means may be applied to any one of a large number of places. For example in the slide valve type here shown it may be either outside or inside of the valve box. In Fig. 2 I have shown the stem 10 as surrounded, outside of the box, with a helical spring 25 interposed between the bracket 26 which carries the pivot 19 and a washer 27 suitably attached to the rod as by the Cotter-pin 28. In Fig. 3 I have shown in full lines a spring 25 as surrounding the rod 10 between the slide valve 9 and the head-end of the valve box, the valve 9 being, in this particular embodiment, embraced be- .tween collars 10, 10a ri id with the rod;

and in the same view in otted lines I have shown a spring 25b interposed between saidl valveand the rear-end of the valve box. In other types or arrangements of valve the spring may be applied in similarly varying modes it being merely necessary that the spring act directly upon the valve with a tendency to move the same in one direction or the other. This may change the relative positions between the lever 21 and the piston 4 but at the same time renders that relative position more nearly constant and will insure an immediate response of the valve to any-movement of the piston.

I have also discovered that the most fruitful source of leakage is past the piston, which tendency is rapidly increased 1n case there be any wearing of the cylinder due to piston-creeping. Leakage at this. point is particularly objectionable from the fact that the loss of pressure on one side becomes added to the other side thus having a doublev effect. To prevent this I form said pist0n with two sets of packing rings and between lthose rings with an external circumto the atmosphere so that leakage from either side of the vpiston will not pass to the'opiposite side. This venting is accomv by means of a hollow-piston rod and can be eii'ected either by means of a bore in the main piston-rod or by the employment of an auxiliary yhollow-rod extending through the opposite end of the cylinder.

In the embodiment of my invention shown in Figs. 2 and 3' I have shown a piston arranged for use withv soft pacln'ngsuch as is generally used when air from the brake system is employed as a motive fluid. In

this embodiment I have shown the piston as v provided with a radial duct 30 communieating by means of a bore 31 with the auX- liary hollow rod 32 which Aassesthrough a gland .S3-carried by the cy lnder head 34. The soft packing 35 is introduced in two sections separated by a skeleton-ring 36 delining a channel which communicates with the duct 30 at all times. In the embodiment of my invention shown in Eig. 4 I have shown the main piston-rod 5 as formed with an axial bore 4:0 communicating with a radial duct 30* inthe piston 4*, said duct communicating with a circumferential groove 4l formed in the metal of the piston. In this case the piston wall at each side of `4this channel is' shown jas formed with' 42 which may be of metal or other substance equally eilicient for use with air or steam.

It will be obvious that my invention is' not limited to the particular features of construction herein described nor limited tothe particular reversing-gear here lshown but numerous changes can be'madewithin the scope of the claims hereto annexed.

I claim is 1. In power operated reversing gear, the e combination with a cylinder secured to the locomotive and a piston therein o ratively connected to the link-motion, ci)e adapted to place either end of said cvlinder communication with a source of fluid presp 'a valve connections between said piston and valve whereby said valve will be restored to central position, and means independent of either of said connections yieldingly forcing said valve in one direction.

2. In a wer operated reversing gear for locomotives the combination with a cylinder having ports and valve mechanism adapted to place either port in communication with a source of fluid pressure supply and to open the other port to the atmosphere, of .a hand lever operatively connected to said valve mechanism, a piston in said cylinder-v operatively connected to the link-motion and also to said valve mechanism, and spring means operatively connected to Said valve mechanism independently of either of said first connections and tending always to move the same in one direction.

3. In mechanism of the character described, the combination of the cylinder and a valve adapted to admit fluid pressure to either end thereof, of a piston in said cylinder, a rod connected to said'piston, a hand controlling lever, operative connections between both said hand lever and said piston rod 'and said valve, anda spring device operatively associated with said connections and adapted to take up all lost motion in the joints of said connections.

4.v In mechanism of the character described, the combination with a, cylinder and piston, of a valve adapted to place either end of'said cylinder in communication with pressure supply, a manually adjustable member, operative conneck v tions between said Bmember and valve, other connections between the piston rod and said Having thus described myA invention, what alveada'ted to close said valve after the samehas n opened by said member, and

yielding 'means operatively associated with saidv connections for automatically taking Aup the lostmotion in the joints thereof.

In testimony whereof I hereunto aix my signature. JOHN H. ALTER.

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