US2558891A - Reversible engine control apparatus - Google Patents

Description

y 1951 R. T. WHITNEY 2,558,891

REVERSIBLE ENGINE CONTROL APPARATUS Filed July 27, 1949 I1 .1 '4 wReversible 5 7/ Engine Crank Sheff rllh ZOO 'Z'LIE' 10o 5 Z) 1 6 6 Reversible .72 '72: Engine Crank Sheff INVEN TOR.

BY aphTZMmney P atented July 3, 1951 REVERSIBLE ENGINE CONTROL APPARATUS Ralph T. Whitney, Irwin, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding,

Pa., a corporation of Pennsylvania 6 Claims. 1

This invention relates to control apparatus and more particularly to control apparatus for reversible engines. 7

In certain control apparatus for reversible engines a direction sensing device is employed which, in the usual form, comprises a friction shoe for actuation into friction contact with a rotating crank shaft of a reversible engine to sense the direction of rotation of same through resultant movement in a corresponding direction to condition certain valve mechanism accordingly.

In such a direction sensing device, the above mentioned friction shoe is moved into sliding frictional engagement with the rotating crank shaft by operation of fluid pressure piston means and held in such sliding engagement for considerable time at the expense of wear on the shoe.

It is a prime object of the present invention to provide an improved direction sensing device for sensing direction of rotation of such as a reversible engine crank shaft which comprises improved means for conditioning the valve mechanism therein.

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

In the accompanying drawing; Fig. l is a schematic view substantially in section of a direction sensing device embodying the invention; and Figs. 2 and 3 are respective modifications of a portion of the device shown in Fig. 1.

Description Referring to Fig. l, the valve portion of the direction sensing device may comprise, in the usual form, a casing adapted to be mounted in a fixed position relative to a reversible engine and either on or immediately adjacent thereto. The casing usually encloses two poppet valves I and 2 contained in chambers 3 and 4 respectively, which chambers are open to such as forward and reverse control pipes I and 200, respectively. The poppet valves I and 2 are arranged side by side with parallel extending fluted stems 5 and 6, respectively, which stems extend into a chamber I common to both and connected to such as a pipe 300. The valves I and 2 control communication between the chamber I and the chambers 3, 4 respectively, hence between the pipe 300 and the forward and reverse control pipes I00 and 200, respectively. A spring 8 in each of the chambers 3 and 4 acts on the respective valve I, 2 to urge sametoward a'closed position, in which position the valve I is shown in the drawing.

7 Application July 27, 1949, Serial No. 106,995

The valve stems 5 and 6 are'adapted to be engaged by two spaced apart operating plungers 9 and II], respectively, which are slidably mounted in the casing and provided with stems II and I 2" which extend outwardly through said casing.- Two rockable cams I4 and I5, fulcrumed on pins secured in the casing, are provided for actuating the stems II and I2, respectively, and thereby the valves I and 2, respectively. These cams may be identical, but reversely arranged, and each is operatively connected to the respective plunger I I, I2 through the medium of a follower element I! which is rockably mounted on a pin secured in the casing. Each of the cams I4 and I5 is provided with a surface I9, which, when'in ngagement with the respective element I1, will unseat the respective valve I or 2. Adjacent to the surface I9, each cam is provided with a recess 20 which recess is adapted to receive the respective element I! to permit movement of'the respective plunger 9 or ID by a spring 2I to a position disposed away from stems 5 or 6 to permit closure of the respective valve I or 2 by the respective spring 8.

The two cams I4 and I5 are operatively connected for movement in unison by a link 22, and since the cams are reversed as above mentioned, movement of the link and cams to the position in which they are shown in the drawing will effect opening of the valve 2 and closing of the; valve I, while movement of said link and cams in a clockwise direction, as viewed in the drawing, to a position in which the surface I9 on the cam- I4 engages the respective element I! will effect opening of the valve I and closing of thevalve 2.

According to a feature of the invention, in lieu of the usual friction shoe for sliding fric tional engagement with such as the outer surface of an engine crank shaft to actuate the valve mechanism, I provide a contact element 30 for rolling engagement with the engine crank shaft or with an element secured to rotate with the crank shaft.

In Fig. l, the contact element 30 may be in the form of a segmental pinion 30 adaptedfor pivotal movement about a pin 3| secured to the casing between two opposite disengaged positions and during such movement into and out of engagement with teeth or serrations formed on the peripheral surface of a gear or similar element 32 which may be formed integral with or be re movably attached to such as the engine cranlr shaft designated in the drawing by an appropriate legend. The contact e1e'ment'30is connected to the pin 3| through the medium of an arm 33 which arm is operatively connected to the link 22 for actuating the valves I and 2 by a link 34, which link 34 is connected at its one end to said arm by a pin 35 (Fig. 2) and to said link 22 at its opposite end by a pin 36. The valves I and 2, cams I4 and I5, links 22 and 34, arm 33, and element 30 are held in the position in which they are shown'in Fig. 1 by action of a tension toggle spring 31 which is pin connected at its opposite ends to the casing by a pin 38 and to the arm by a pin 39. Such position of the above elements is defined by contact of the element 30 with the projecting end of a piston rod 40 which is operatively attached to an actuating piston 4| shown in the drawing in a repose position, with said element 30 disposed away from the gear 32 at this time. In a position opposite to that in which it is shown in the drawing, the contact element 30 will be held by spring 31 in contact with a similar piston rod 42 attached to an actuating piston 43 which will then be in its repose position in which it is shown in the drawing, and the links 34 and 22 and cams I4 and I will be so positioned, as previously described, that the valve I will beopen and the valve 2 closed with the chamber I, hence pipe 300, closed to the chamber 4, hence pipe 200, and open to chamber 3, hence to the pipe I00. The spring 31 will act to hold the parts of the device in the above defined respective positions.

The pistons 4| and 43 are slidably disposed in respective oppositely arranged, coaxially aligned actuating cylinders 45 and 46 disposed on opposite sides of the contact arm 30. Each of the cylinders 45 and 46 may contain a light compression spring 50 disposed in an atmospheric chamber 5| at one side of the respective piston 4| or 43, which spring is arranged to urge said piston toward its repose position in which it is shown in the. drawing in contact with a shoulder 52 formed in the casing. In each of the cylinders 45, 46 at the opposite side of the respective pistons 4| and 43 there is a pressure chamber 55, which in cylinder 45 is connected to a branch of the forward control pipe I00, and in cylinder device 46 is connected to a branch of the reverse control pipe 200.

In operation, with the engine crank shaft turning in its Forward direction, indicated by an arrow so titled in the drawing and with the contact element 30 disposed in the position in which it is shown in the drawing, with pipe 300 consequently connected to the reverse control pipe 200 by way of the unseated valve 2, assume that fluid under pressure is supplied to the forward control pipe I00 while the reverse control pipe 200 remains vented to atmosphere. Such fluid under pressure supplied to the forward control pipe I00 will flow to the pressure chamber 55 in the cylinder 45 and will cause, through movement of the piston 4| and attached rod 40, resultant movement of the contact element 30 into engagement with the teeth on gear 32 on the crank shaft rotating in its Forward direction. So long as the crank shaft continues to turn in its Forward direction, the contact element 30 will be held against further movement by rubbing contact with gear teeth 32. The effect of pressure of fluid in the chamber 55 acting on the piston 4| will be kept just sufiicient to maintain such rubbing contact, as an excessive force of element 30 on gear teeth '32 is not desired from the standpoint of wear and may be kept at a minimum through proper design of the spring 50 for a given size piston 4| and for a given pressure of fluid. As soon as the engine crank shaft, hence th gear 32,

4 I reverse direction of rotation, however, that is, from Forward to Reverse in compliance w t the example, the teeth on gear 32 will mesh w' t the teeth of the contact element 30 to cause piivotal movement of the arm 33 about pin 3| to th opposite side of said gear, whereupon spring 31 will cause it to assume its opposite position in which the element 30 is disposed away from th 35 teeth on gear 32 and in engagement with rod 4 2 attached to piston 43 in its repose position in which it is shown in the drawing, since chamber 55 in cylinder 46 is vented via the ahead control pipe I00 at this time. Such pivotal movement of the arm 33 will cause shifting of cams I4 and I5 and thereby resultant closing of the valve 2 and opening of the valve I for connecting the pipe 300 to the now vented ahead control pipe I00 for reasons beyond the scope of the present invention.

Similarly, while the crank shaft is yet rotating in its Reverse direction, if fluid under pressure is supplied to the reverse control pipe 200 while the forward control pipe I00 is vented, the piston 4| in cylinder 45 will be returned by spring 50 to its repose position, while fluid under pressure supplied to pipe 200 will flow to chamber 55 in cylinder device 46 and cause the piston 43 to move the contact element 30 into rubbing contact with the teeth on gear 32. As soon as the engine crank shaft reverses its direction of rotation, that is from Reverse" to Forward, the teeth on gear 32 will mesh with the teeth of element 30 to move arm 32 to the opposite side of said shaft whereupon spring 31 will snap it to its original position in which it is shown in the drawing, with said element 30 in contact with rod 40 attached to piston 4| in its repose position. As will be appreciated from previous description, the valves and 2 will be positioned accordingly through resultant movement of links 34, 22 and cams I4 and I5.

In order to relieve shock and prevent undue wear of the two end teeth or serrations on element 30 which may result from rubbing engagement with the teeth on member 32 said end teeth may be replaced by end teeth 10, referring to Fig. 2, which are pivotally connected to the element by means such as pins II and urged toward symmetrical relationship with the other teeth by such as leaf springs I2 in such a fashion that the teeth I0 will act a pawls which will ride the teeth on the crank shaft in one direction of its rotation and which will become effective to take hold when the crank shaft reverses its direction. The springs 12 may be secured by means of such as screws I3 to opposite sides of element 30 and arranged to urge the teeth I0 toward engagement with respective shoulders I4 formed in said element to accommodate the teeth. Rubbing engagement of the tooth I0 at either side of element 30 with teeth on the crank shaft will cause said tooth to leave shoulder I4 and pivot about pin II against action of the respective spring I2, thereby reducing the impact effect between element and shaft, while mating engagement of the tooth 10 with teeth on said shaft will allow return of said tooth into engagement with shoulder 14 to cause pivotal movement of arm 33 to the opposie side of said shaft in fashion as aforedescribed herein.

In lieu of teeth or serrations either on the contact element 30 or on the crank shaft or a gear associated therewith, the contact element may be provided with a segmental shoe of resilient material, such as rubber, as shown in Fig. 3. The

- craink shaft Summary It will be seen that I have provided improved means for conditioning such as valve mechanism comprised in direction sensing devices according to the direction of rotation of a reversible e11 ,gine. l Having .now described the invention, what I claim as new desire to secure by Letters Patentf-is:

1. Apparatusfor sensing direction of rotation of a reversiblerotatable shaft comprising in combination, apivotal element having a rest position at either side of and out of contact with said shaft and being adapted upon contact with said shaft to be moved thereby in the direction of either one or the other of said positions according to the direction of rotation of said shaft, a piston arranged to be operated by fluid under pressure to move said element from one of said positions into contact with said shaft, another piston arranged to be operated by fluid under pressure to move said element from the other of its positions into contact with said shaft, an engine forward control pipe arranged to convey fluid under pressure to and from said one piston, and an engine reverse control pipe for conveying fluid under pressure to and from said other piston.

2. Apparatus for sensing direction of rotation of a reversible rotatable shaft, comprising in combination, an annular element associated with said crank shaft for rotation therewith and comprising gear-like teeth around its peripheral face, a pivoted element comprising a segment having a series of gear-like teeth for intermeshing with the teeth of said annular element for moving said pivoted element from either side of said shaft in a direction toward a rest position at the opposite side and out of contact with said annular element, means for moving said pivoted element from either one of its rest positions into contact with said annular element, means carried by said pivoted element pivotally carrying opposite end teeth of said series, said pivoted element comprising means for supporting said end teeth for driving said pivoted element by said annular element only upon rotation of said annular element in a. direction for moving said pivoted element from one side of said crank shaft toward the opposite side.

3. Direction sensing apparatus comprising in combination with a rotatable shaft, a contact element movable from either of two disengaged positions at opposite sides of said shaft into engagement with said shaft to be moved past said shaft by such engagement upon reversal in direction of shaft rotation, toggle spring means operatively connected. to said contact element to move said contact element to a respective one of said disengaged positions after passing said shaft, and fluid pressure means operatively connected to said contact element to overcome action of said toggle spring means to effect said engagement.

4. Direction sensing apparatus comprising in combination with a rotatable shaft, shaft gear teeth secured for rotation with said shaft, a contact element having rigidly attached corresponding gear teeth movable from either of two disengaged positions at opposite sides of said shaft into rubbing engagement with said shaft gear teeth when said shaft is rotating in one direction and movable pastsaid shaft by meshing engagement with said shaft gear teeth upon reversal in direction of shaft rotation, toggle spring means operatively connected to said contact element to move same to a respective one of said disengaged positions after passing said shaft, and fluid pressure means operatively connected to said contact element to overcome action of said toggle spring means and effect said engagement.

5. Direction sensing apparatus comprising in combination with a rotatable shaft, an annular element having serrations about its periphery and arranged for rotation with said shaft, a pivotal element having serrations at one end for interlocking engagement with the serrations on said annular element for moving said pivotal element past said shaft, toggle spring means operatively connected to said pivotal element to move said pivotal element to a rest position free of said shaft after passing same, and fluid pressure means operatively connected to said pivotal element to move same against opposition of said toggle spring means for effecting such engagement.

6. Direction sensing apparatus comprising in combination with a rotatable shaft, a contact element having a resilient shoe movable from either of two disengaged positions at opposite sides of said shaft into endwise engagement with said shaft for rolling movement past said shaft upon reversal in direction of shaft rotation, toggle spring means operatively connected to said contact element to move same to a respective one of said disengaged positions after passing said shaft, and fluid pressure means operatively connected to said contact element to overcome action of said toggle spring means and effect said engagement.

RALPH T. WHITNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 740,547 Fiske Oct. 6, 1903 1,748,307 Peters Feb. 25, 1930 2,042,915 Twist June 2, 1936 2,464,998 Stevens Mar. 22, 1949

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