US2049740A - Counterbalancing mechanism for steam locomotives - Google Patents

Description

J. KUPKA Aug. 4, 1936.

COUNTERBALANCING MECHANISM FOR STEAM LOCOMOTIVES 2 sheets-Sheet 1 Filed May 29, 1934 a/OV KUPKA INVENTOR- Aug. 4, 1936.

J. KUPKA COUNTERBALANCING MECHANISM FOR STEAM LOCOMOTIVES Filed May 29, 1934 2 sheets-Sheet 2 JOHN Ku/(A INVENTOR ATTORNEY Patented Aug. 4, 1936 oni-ran stares y 2,049,740 y coUN'rnnnALANciNc MscHANrsi/i Fon lS'illlitAMlf LOCOMTIVES John Kupka, Schenectady, N. Y.,

Walter D. Maring assigner toV Application May 29, 1934, Serial 728.123

4 claims. (ci. 121-415) f This invention pertains to steam locomotives and more particularly to means for counterbalancing the reciprocating parts of a steam locomotive having two cylinders with main pins set at an angle of ninety degrees.

In kthe counterbalancing arrangements heretofore employed the reciprocating masses of the driving mechanism of suchV steam locomotives are counterbalanced by providing balance weights in the wheel centers so arranged that the hori- Zontal component of the said revolving balance Weights in the wheel centers counteracts, partially, the inertia effects set up by the periodic movement of the cross heads, pistons and piston rods as well as the main rods.

'Ihe inconvenience attendant upon this meth- 0d of counterbalancing is a most pronounced increase in the track stresses at higher operating speeds.

Due to the fact that revolving masses are employed to counterbalance. purely reciprocating masses, a free component acting at right angles to the path of the reciprocating masses appears. Said free component tends in a steam locomotive of conventional design to cause va periodic fluctuation in the driving wheel loads where such balance weights are provided. Since the magnitude of this additional track stress increases withl the speed of the locomotive, it obviously is necessary to restrict the maximum operating speed of the locomotive to a rate much below its capacity.

yThe object of thisinvention is to effect a counterbalancing of the reciprocating masses of such steam locomotives without having to fear the harmful eiect oi the dynamic augment of the static axle load regardless of the operating speed'- Another object is to effect a decrease of tire wear Which is directly" attributable to-` said dynamic augment-which is often referred to as hammer blowl According to thisV invention, the valve motion, which operates the piston valves of the locomotive, is: rearranged to eliminate the balance weights in the wheel centers as far as the purely reciprocating parts are concerned.

As has already been mentioned, it is necessary that the main pins ofl the locomotive be set at ninety degrees with respect to each other and inasmuch as any valve motion to operate pisto-n valves is derived by combining the movement of two eccentrics or their equivalents, one with a constant throw which is synchronous, as far as movement and angle are concerned, with the main: pin while the other isset at ninety degrees to the main pinvvv and is provided with a variable throw or its equivalent in the shape of a variable travel, it is here prcposedto make use of the main pinset-up of the main driving mechanism of thellocomotive in the following man- 5."

trolled by said eccentric armor its equivalent 10i is now transferred across `the engine Vto the other side thereof without, however, changing its constant angular relationship with the main pin. It will be apparent atv once` that since the main pins of any conventional steam locomotive are l54` set mutually yat ninetydegrees'the new position of the eccentric arm or its equivalent in relation tothe main-pin atthe other side of the locomotive can either be one of total opposition or, alternatively, one of'complete juxtaposition.

Fig.' 1 is a fragmentary elevational View of the right side of a locomotive, depictingJal valve motion of the Walschaert/type together-with a portion of the right cylinder and one of the driving wheels; and

Fig. 2 is a perspective viewed from the left side of the locomotive-the boiler, driving wheels and frame being. omitted in order to showmore clearly the valve motionsv and other essential parts on both sides of the locomotive and their inter- 30 relationsV Y Ordinarily, the valve motion located on either side of alocomotive'serves to'operate the piston valve on the same side, but here that does not hold true.` On'the contrary, the principal parts 35 of the valve motions in the present case are each transposedto the side of the locomotive opposite their respectively associated piston valves.` Thus, the principal parts of the valve motion illustrated in Fig. l operates the left hand piston valve- 40 the transposition being effected by means of a suitable cross-shaft4 In Fig. 1, vI is a main pin on a right hand driving wheel; 2 is an eccentric arm carried by the same wheel and sodisposed that the eccentric 45 pin 2l is located diametrically opposite the main pin; 3 is an eccentric rod having an enlarged portion 3a which is preferablyformed with an internal cavity lled with lead to serve as a counter-balance weight; 4 is anexpansion link of the 50 Vusual form; 5 a radius rod; 6' a lever arm attached to a cross-shaft 'l extending transversely of the locomotive; 8 is another cross-shaft like- Wise extendingtransversely of the locomotive; 9 is alever arm attached tocross-shaft 8; l0 is the 55 usual combination lever; II a. union link; I2 the right hand cross-head; I3 a link interconnecting the combination lever with the piston valve stem; I4 is an adjusting member on the piston valve stem; I5 is a suitable bracket for the cross-shaft bearings; I6 is a lifting bar; I1 the reversing shaft; I8 the reversing lever which is connected to the reverse gear in` the cab; I9 the right hand piston rod and 20 the main rod interconnecting the cross-head and main pin.

In the perspective View, Fig. 2, the valve motion and other parts located on the left side of the locomotive and corresponding to like parts on the right side are identified by like reference numerals with prime marks added. Thus, the main pin on the right side is identified by reference numeral I While the left main pin is identified by numeral I'.

In order not to obscure any of the parts, a clear showing of which is considered essential, the driving wheels and axle have been omitted in Fig. 2 and the right hand main rod is shown broken off near its main pin.

It will be observed that, on the whole, the modified valve motion Vis very similar to the conventional Walschaert valve motion. The physical diiferences consist in (l) the location of the eccentric pin at an angle of one hundred and eighty degrees to the main pin instead of ninety degrees; (2) the provision of an auxiliary weight on the eccentric rod and; (3) the provision of cross-shafts and lever arms for effecting the necessary transpositions.

The main pins on either side of the locomotive are disposed mutually at ninety degrees in accordance with conventional practice. Hence, the eccentric pin on each side is at ninety degrees to the main pin on the opposite side; and since the valve motions are, in part, transposed, it follows that the resultant piston valve sequences are identical with those obtained with the conventional arrangement. The whole purpose of this transposition is to enable putting the eccentric pin on each side at one hundred and eighty degrees to the main pin on the same side so that the motion of the eccentric rod and its auxiliary weight will be at all times in direct opposition to the motion of the horizontally reciprocating drivng members including the piston, pistonrod, crosshead and main rod. The object, as stated at the outset, is to counterbalance the inertia eiect of these last mentioned reciprocating members Without putting the necessary balance weights in the driving wheels and to do this in such a way as to avoid as faras practicable vertical reciprocation of the balance weightsthus eliminating or greatly reducing the hammer blow effect.

In the arrangement described a large part of the valve motion including particularly the eccentric rod and its auxiliary weight reciprocate in a generally horizontal plane. The auxiliary weight is located at that end of the eccentric rod having the least amplitude of vertical motion. There is, it is true, some vertical as well as horizontal reciprocation of the auxiliary weight and the former is theoretically detrimental; but its magnitude is relatively small and the greater part of the auxiliary weight is borne by the frame of the locomotive which is spring supported. The residual hammer blow effect due to the vertical reciprocation of the eccentric rod and auxiliary weight is relatively insignificant. It could, manifestly, be almost entirely eliminated by an obvious change of design, but to do so would introduce complications Which it is desirable to avoid. A compromise design, such as that illustrated, approaching the ideal but falling a little short of it, is commercially preferable to the introduction o1' complications incidental to a realization of 'the theoretical ideal solution. In other words, it is not considered commercially feasible to so design and construct the mechanism that the auxiliary weight will move only in a straight horizontal path; and particularly is that true in applying the invention to existing locomotives. Oi course, such refinements might be resorted to in designing new locomotives if the designing engineer were so disposed; but it is doubted that the gain would offset the added complication. That, however, is a matter of individual opinion and I am not to be construed as disclaiming such alternative arrangements which come within the scope of my broad inventive concept.

It, doubtless, will be clear that the auxiliary Weight 3cr-is not the only part of the moving mass which serves to counter balance the horizontal inertia effect of the driving members. The eccentric rod as awhole and the expansion link, in part, contribute to the aggregate counterbalancing mass. On the other hand, those parts of the valve motion which move in the same direction as the adjacent driving members contribute somewhat to the inertia effect to be counterbalanced.

While I have shown an auxiliary weight as a distinct entity, it will be obvious that the necessary added mass could beV incorporated into the design of the valve motion parts in such a way that it would not appear as a distinct entity. Also it will be apparent that the auxiliary weight need not necessarily be incorporated'as an integral part of the valve motion-although that is considered by far the 'most convenient and practicable arrangement.

Cross-shafts I and 8 are provided at their opposite ends with lever arms corresponding to lever arms 9 and S respectively-the lever arm at the Vremote end of cross-shaft 'I being connected with the combination lever on the left side of. the locomotive and the lever arm on the remote end of cross-shaft 8 being connected to the radius rod on the left side. The valve motion parts comprising elements I0, II, and I3, obviously, in each case are components of the valve motion operating the piston valve on theirown respective sides of the locomotive. Since these vlatter' parts are components of the valve motion as a whole, it follows that the valve motions are not transposed in their entireties. Those parts which are transposed I choose to designate for convenience of identification as the principal parts ofthe valve motion.

It is believed that anyone skilled in the art will be able to at least roughly calculate the Y amount of auxiliary weight needed to effect a balance in any particular case; but in any event it can be determined by trial.

Inasmuch as th-e inertia effects are proportional to the square of the velocity it is highly desirable that the velocity of the opposing masses be equal at all times. This means that the eccentric pin is preferably located at the same radial distance from the center of rotation of the driving wheels as the main pin.V Any arrangement which would not afford equal velocities at all times between the opposing masses would not maintain a balance at all speeds because the masses are of xed value.

The present inventionmay, of course, be used with suitable modifications with other forms of valve operating mechanisms and is, therefore, not to be construed as limited in its application to the Walscliaert type of valve motion.

What is claimed is:

1. The combination in a steam locomotive of a driving wheel having a main pin, reciprocatory driving means connected with said main pin, an eccentric pin carried by said driving Wheel and disposed diametrically opposite said main pin, and a valve motion connected to said eccentric pin, said valve motion including a reciprocatory counterbalancing mass arranged to move in a path which is at least approximately parallel to the path of said driving means and at all times in directional opposition to said driving means.

2. In a steam locomotive, tWo steam cylinders disposed individually on opposite sides of. said locomotive, a pair of driving wheels having a common axis of rotation and likewise disposed individually on opposite sides of said locomotive, a main pin for each of said driving Wheels individually, said main pins being disposed mutually at an angle of ninety degrees about the center of rotation of said driving Wheels, an eccentric pin for each of said driving Wheels individually, each of said eccentric pins being disposed diametrically opposite its associated main pin along a line intersecting the axis of rotation of. said driving Wheels, piston valves for each of said cylinders individually, a pair of valve motions for operating each of said piston valves individually, the principal part of each of said valve motions being disposed at the side of the locomotive opposite its associated piston valve, said principal parts including, in each case, an eccentric rod which is connected to the eccentric pin on the side opposite its associated piston valve, said valve motions each including a counterbalancing mass, and reciprocatory driving means on each side of the locomotive interconnecting said cylinders and driving Wheels, the aforesaid Ycounterbalancing mass on each side of the locomotive being of. a suitable magnitude to bring about a substantial counterbalancing of the horizontal inertia effect of the said reciprocatory driving means on the same side of the locomotive.

3. The combination in a locomotive of a pair of steam cylinders disposed individually on opposite sides thereof, a piston valve for each of said cylinders individually, a pair of driving wheels having a common axis of rotation and disposed individually on opposite sides of said locomotive, main pins for said driving wheels individually, disposed mutually at an angle of, ninety degrees f about said center of rotation, eccentric pins carried by said driving wheels individually and disposed in each instance at an angle of one hundred and eighty degrees about said center of rotation` to the main pin carried by the same driving wheel, and a valve motion interconnecting each of said eccentric pins with the piston valve for the cylinder on the opposite side of the locomotive.

4. In a steam locomotive, a steam cylinder, a driving Wheel, reciprocatory driving means interconnecting said steam cylinder with said driving Wheel, an eccentric pin carried by said driving Wheel, and a valve motion including an eccentric rod, said eccentric rod being connected at one end to said eccentric pin, and a lumped counterbalancing mass carried by said eccentric rod at a point remote from said eccentric pin, said counterbalancing mass, supplemented by the mass of said valve motion, being of such magnitude as largely or Wholly to counterbalance the horizontal inertia eiect of said driving means.

JOHN KUPKA.

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