US2072707A - Locomotive - Google Patents

Description

March 2, 1937.

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March 2, 1937.

v. z. cARAcRlsTl LOCOMOTIVE Filed Aug. 11, 193e Y 3 Sheets-Sheet 2 lNVENToR l//RG//v/af Z (4mm/m ATTORNEY arch 2, 1937.

V. Z. CARACRISTI LOCOMOTIVE Filed Aug. 11 193e s sheets-sheet 5 INVENTOR V//v//ww Z W40/w77 @NWN ENQ/M ATTORNEY Patented Mar. 2, 1937 UNITED STATES www PATENT OFFICE LOCOMOTIVE Application August 11, 1936, Serial No. 95,475

Claims.

The present invention relates to locomotives in which power is furnished by reciprocating engines and has for its purpose the provision of an improved locomotive of this kind.

5 The present case is a continuation in part of my application Serial Number 76,750, led on April 28,'1936.

The usual arrangement in these locomotives is to have a cylinder on each side, each of the pistons lo being connected through piston rod, cross-head and connecting rod to the driving pin on the main driver on its side and power being transmitted to the other drivers through side rods.

In order to furnish all the power by means of tWo cylinders, these cylinders and their pistons must be of large size, and the parts transmitting the power from the pistons to the drivers must be correspondingly heavy. The distributing valves must likewise be large in order to admit the required amount of steam without excessive wire drawing and to permit the exhaust to leave without undue back-pressure.

'Ihese factors result in placing a limit on the speed at which it is possible or advisable to run such locomotives. The large masses comprising the piston, piston rod, cross-head and connecting rod must be reversed twice for each complete revolution of the drivers and this throws great stresses on the cylinders themselves and on the o parts transmitting the force between the piston and the drivers as well as on frames and other parts of the locomotive.

The large size of the distributing valves results when their movement and reversal occurs at high speeds in throwing excessivel stresses on the parts involved.

It is one of the main purposes of my invention to remove these difficulties and to provide a locomotive which can safely be operated at high 40 speeds.

Railroads have found it necessary in the past to use two quite distinct types of locomotives, one of these types being designed for passenger service and the other for freight service. The

former type is capable of pulling relatively short trains of passenger cars at high speeds and the latter is designed for pulling heavy freight trains at lower speeds. If one type could be designed to serve both purposes, this would evidently be a great advantage as the number of locomotives required by a railroad would be considerably reduced.

My invention provides a locomotive meeting this condition as with my novel design the same locomotive will be adapted for either service.

(Cl. 10S-120) To refer more specifically to one feature of the invention, the particular disposition' of the cylinders which I use and other features which I employ and which will be fully described hereinafter reduce the amount of unbalanced masses to a minimum and moreover keep the stresses resulting from such unbalanced masses as are present confined within the engine frame. There is therefore no appreciable impact or blow on the rail from this cause and as far as this factor is concerned, the revolutions of the drivers per minute and the speed of the locomotive may safely be much greater than is the case where there are substantial unbalanced masses, which is of necessity often the case in present designs.

Further and more detailed advantages of the invention will be clear from the following description.

In describing my invention reference will be made to the accompanying drawings. In these Fig. 1 shows a later-a1 elevation of a locomotive according to my invention, this gure being rather diagrammatic and meant mainly to illustrate the relative location of the cylinders, crank shafts and drivers. Fig. 2 is a lateral elevation of a portion of the frame in the vicinity of the drivers and shows on a somewhat enlarged scale the means for carrying the cylinders, cross-head guides and crank shafts, one of the cylinders and its power transmitting parts being shown in position. Fig. 3 is a similar view still further enlarged of a portion of the frame with one of the castings carrying a cylinder and two of the castings carrying crank shafts. Fig, 4 is a. half top view of Fig. 3. Fig. 5 is a section on line 5 5 of Fig. 4, the cylinder having been omitted both in this and in the preceding figures for the sake of clarity; Fig. 6 is a cross-sectional enlarged view on line 6 6 of Fig. 2; and Fig. 7 is a view similar to Fig. 1, portions however being omitted, showing a variation.

'Ihe general arrangement used by me in carrying out my invention is illustrated more or less diagrammatically in Fig. 1. In the locomotive here shown to illustrate the invention there are four drivers I l on each side of the locomotive. It will be clear from what follows that some other number might be used. These drivers are preferably and in accordance with ordinary practice, although not necessarily, fixed on their axles 2 2. That they need not be so fixed to the axle and that in fact the axle need not extend through from side to side but that the two opposite drivers might have independent short aXles will be clear from what is said below.

'I'he cylinders are located at a level above the drivers and at an inclination to the horizontal. These cylinders appear in Fig, 1, at 4 4. They are so inclined to the horizontal that the axis of each intersects the axis of corresponding crank shaft 3.

Steam is supplied to the cylinders by means of the pipe 5 and the branches 'i--l and the exhaust is carried off by the pipe 9 to which it is delivered by the branches l l-l I. It will be understood that the necessary valve gear, not shown, for controlling the admission and exhaust of the steam will be used, and that such gear may be of any usual or preferred type.

This location of the cylinders is necessary vbecause of space limitations. With the cylinders so placed and so inclined, a diiculty arises if the pistons are connected directly to the drivers by means of a cross-head and connecting rod.

An alternating upward and downward thrust in that case'would be exerted on the driver, the downward thrust causing a pounding blow on the rail and the upward pull removing some of the weight from the driver and transferring it to the other drivers, thus decreasing the tractive power that can be exerted by the driver. To yavoid this 'the following provision is made.

Instead of transmitting the power from the cross-head 6 of each cylinder directly to the corresponding driver, I transmit it to an auxiliary crank shaft or jack shaft 3 and from it to the driver by means of the rod lil. The crank shafts 3 3 are placed between pairs of drivers and forward of the front pair and lie in the same plane with the axles of the drivers or at least substantially so. They are, as will be more fully described below, mounted in xed space relation toY the cylinders. The power transmission from the crank shafts to the drivers is thus always in a horizontal direction and the downward and upward components of the force exerted on the drivers are avoided and all such stresses are absorbed within the frame itself.

It will be noted from the above -brief outline of the general disposition of the cylinders and drivers that each pair of drivers is connected to its pair of cylinders but is wholly independent of the other drivers and other cylinders.

The supports for the cylinders and vfor the crank shaft bearings may be made integral with the frames if desired. In the form of the invention herein illustrated and described, however, the invention is shown as applied to a locomotive with frames of the ordinary construction and the parts necessary for supporting the cylinders, crank-shaft bearings, etc. are separately fabricated and secured to the frame.

The frame is in accordance with ordinary ipractice made up of two similar halves Ill- I4 connected by suitable cross-bracing, not shown. To carry the cylinders I preferably provide separate castings iii-I6, one for each pair of cylinders. With the exception of the front one, these castings will all be alike thereby reducing the cost of manufacture and providing for interchangeability.

Referring more particularly to Figs. 4, 5, and 6, one such casting i6 is here illustrated. It consists of a more or less skeletonized body I8 extending from side to side of the locomotive and resting on each of the frames at the points 2tl- 20. The casting is secured to the frame by means such as the bolts 22-22 and is provided commodate a cylinder which is secured in place by any desired means such for example as bolts 25 passing through anges 21 on the cylinder and flanges 29 on the cradle.

The bearing points 20-20 are located so far forward and backward from the cylinder cradle 24 that firm support is furnished to the cylinder.

To support the cross-head guides I providebrackets 2% on the two sides of the castings I6. The brackets on each casting serve to carry the cross-head guides for the cylinder forward of it. It is for this reason that the castings are not all exactly alike. The foremost one of them, I6a, carries no such bracket and may be somewhat shortened in the forward and aft direction. For the rearmost cylinder a separate casting IBb is preferably provided carrying the guide bracket 26a. The casting |619` extends across the two frames ill and is secured to them in any preferred manner.

The means for carrying the crank shaft comprises for each pair of cylinders a casting 30 resting on the lower branch of each half of the frame and being secured to it by any suitable means, such as bolts 32-32. 'Ihe crank shaft 3 extends at each end through a bearing 34-34.

An important feature in connection with the transmission of the power through the crank shafts is the angular disposition of the crank pins receiving the power from the piston through the connecting rods 8 relatively to the pins delivering this power from the crank shafts to the rods I0. Each crank has a double pin at each end.

Of these the pin 36 is laterally in line with theY axis of the correspondingcylinder Il and is engaged by one end of the corresponding connecting rod, the other pin 38 being inline with the pin l2 on the driver and being connected to it by the rod I0. The two pins 36 and 38 of each crank are not co-axial but are relatively offset, subtending an angle at the center equal to the angle at which the cylinder 4 is inclined to the rail on which the drivers run. The eifect of this is that unnecessary .and excessive stresses on the cylinder heads and parts transmitting the power from the piston to the driver are avoided. When the rod lil is in its extreme forward or in its extreme backward position, at which time the axis of the driver, the axis of the crank shaft and the pins 38 and i2 are all in line, or, in other words, when the pin 38 is on dead center, the

piston is at one end of its stroke and will therefore be exerting no force. Furthermore, when the connecting rod 8 is at right angles to its crank radius and therefore transmitting the maximum power, the rod I0 will be at right angles to its crank radius and therefore in the best position to transmit this maximum power to the driver with minimum stresses to the pins and rod.

The pin 36 at one end of each shaft 3 is 90 in advance of that at the other end.

Each of the cross-head guides is connected by suitable means to its bracket 26. A transverse section of such bracket, guide and cross-head is shown in Fig. 6. The guide is of the cross-sectional shape shown at 40. It has a T-slot 4I into which ts the corresponding portion of the cross-head 42.' The pin 44 connects the forked upper Iend 43 of the connecting rod to the crosshead.

The presence of the castings supporting the cylinders and the crank shafts makes it possible to omit some of the ordinary cross-bracing between the two halves of the frame.

From the above description it will be underto a pair are of the same size.

stood that each pair of drivers together with a corresponding pair of cylinders and the parts operatively connecting the two constitutes a unit separate and independent from the other units. A number of advantages result from this. For one thing repairs to one of the cylinders or associated parts will involve the handling of comparatively light parts only and the repairs can be rapidly made and need not tie up the locomotive for any lengthy period. In practice, for example, a cylinder or a crank shaft can be removed and a substitute put in place usually without any lossof time of the locomotive from service, the defective part being then repaired and kept on hand as a replace part. In fact, an entire unit from cylinders to drivers and including the cylinder supports and crank shaft supports or any portions of such a unit can be removed and a substitute unit or part put in without tying up the locomotive for any extended period of time.

A further and important advantage is that the drivers need not all be of exactly the same diameter. It is sufcient if the two belonging It is entirely permissible to remove one such pair of drivers, turn down the tires or replace them and put the drivJ ers back into place without doing anything to the drivers, whereas according to the locomotive of the usual design if one tire needs turning down or replacing, all the others must have similar treatment as all the tires must be of the same size.

The location of the cylinders in accordance with the invention makes it possible to adopt cylinder proportions with relatively larger diameters as compared with the stroke than is possible with locomotives of the ordinary type under existing track clearance conditions. with the elimination of substantially all unbalanced rotating masses, and with the absorption within the frame of the vertical components of the force exerted by the pistons makes it possible to use locomotives of the new design interchangeably in freight or passenger service. Such a locomotive according to the new design may for example be used in freight service and have suicient horsepower output to pull a heavy train at forty-live miles an hour, and may also be used in passenger service to pull a train at eighty or eighty-five miles an hour without the piston speed exceeding allowable limits, or severe pounding on the rail o-r straining of locomotive parts occurring.

It will be clear that the location of the auxiliary crank shafts relative to their associated wheels may be changed as shown in Fig. 7, where each such crank shaft is put back of its associated pair of wheels instead of forward of it. The several rods lilo then extend forward to the crank pins of the respective drivers. Other things remain unaltered and the advantages of the invention are evidently realized equally well by this arrangement.

What I claim is:

l. In a locomotive, the combination of a plurality of axles each mounted in bearings and having driving wheels at its opposite ends, a plurality of auxiliary crank shafts mounted in bearings and one lying parallel to and forward of each of the axles, a crank pin on each of the wheels, a doublepin crank on each end of each auxiliary crank shaft, a rod connecting each wheel crank pin to one of the pins of the corresponding double-pin crank of the nearest forward crank shaft, a cylin- This, coupled der for each double-pin crank mounted rigidly relatively to the crank shaft at right angles to it and with its axis inclined to the horizontal and intersecting the axis of the crank shaft, a crosshead for each cylinder, and a connecting rod from each cross-head to the second pin of its doublepin crank, the two pins of each double-pin crank subtending an angle equal to thatv at which the cylinders are inclined to the horizontal.

2. The combination in accordance with claim 1, said cylinders each being located forward of its associated crank shaft.

3. The combination in accordance with claim 1, the cylinders and the auxiliary crank shafts being mounted in bearings carried by the frame of the locomotive.`

4. The combination according to claim 1, each cylinder being secured to the frame by meanspermitting its ready removal and replacement.

5. The combination according to claim 1, each cylinder being secured to the frame by means permitting its ready removal and replacement, there being further provided guides for said crossheads rigidly secured to the frames.

6. The combination according to claim 1, the cylinders and crank shaft bearings being rigidly fixed to the frame, while the bearings of the wheel axles have the usual freedom of vertical motion relatively to the frames.

7. In a locomotive, the combination of a plurality of axles each mounted in bearings and having driving wheels at its opposite ends, an auxiliary crank shaft associated with each pair of driving wheels and mounted in bearings and all lying parallel to and in the same horizontal plane with the axles, a crank pin on each of the wheels, a double-pin crank on each end of each auxiliary crank shaft, a rod connecting each wheel crank pin to one of the pins of the corresponding doublepin crank of its associated crank shaft, a cylinder for each double-pin crank mounted rigidly relatively to the crank shaft at right angles to it and with its axis inclined to the horizontal and intersecting the axis of the crank shaft, a cross-head for each cylinder, and a connecting rod from each cross-head to the second pin of its double-pin crank, the two pins of each double-pin crank subtending an angle equal to that at which the cylinders are inclined to the horizontal.

8. In a locomotive, the combination of a plurality of axles each mounted in bearings and having driving wheels at its opposite ends, a plurality of auxiliary crank shafts mounted in bearings and one lying parallel to and to the rear of each of the axles, a crank pin on each of the wheels, a double-pin crank on each end of each auxiliary crank shaft, a rod connecting each wheel crank pin to one of the pins of the corresponding double-pin crank of the nearest crank shaft to the rear of the wheel, a cylinder for each double-pin crank mounted rigidly re1- atively to the crank shaft at right angles to it and with its axis inclined to the horizontal and intersecting the axis of the crank shaft, a crosshead for each cylinder, and a connecting rod from each cross-head to the second pin of its double-pin crank, the two pins of each doublepin crank subtending an angle equal to that at which the cylinders are inclined to the horizontal.

9. In a locomotive the combination of a plurality of driving wheels, the wheels of each pair being rotatably mounted on opposite sides of the locomotive co-axially with each other, a plurality of auxiliary crank shafts each associated with a pair of driving wheels and mounted in bearings and all lying parallel to and in the same horizontal plane With the axes of the Wheels, a crank pin on each of the wheels, a double-pin crank on each end of each auxiliary crank shaft, a rod connecting each Wheel crank pin to one of the pins of the corresponding double-pin crank of its associated crank shaft, a cylinder for each double-pin crank mounted rigidly relatively to the crank shaft at right angles to it and With its axis inclined to the .horizontal and intersecting the axis of the crank shaft, a cross-head for each cylinder, and a connecting rod from each cross-head to the second pin of its double-pin crank, the two pins of each double-pin crank subtending an angle equal to that at which the cylinders are inclined to the horizontal.

110. Ina locomotive, the combination of a plurality of axles each mounted in bearings and having driving Wheels fixed at its opposite ends, an auxiliary double-pin crank for each driving wheel mounted to rotate about an axis parallel to the axles and in a plane with them, a crank pin on each of the Wheels, a rod connecting each Wheel crank pin to one of the pins of the corresponding double pin crank, a cylinder for each double-pin crank mounted rigidly relatively thereto and at right angles to its axis of rotation, the cylinders being inclined to the horizontal and so placed that the axis of each cylinder in` tersects the axis of the corresponding doublepin crank, a cross-head for each cylinder, a connecting rod from each cross-head to the second pin of its double-pin crank, the two pins of each double-pin crank :subtending an angle equal to that at which the cylinders are inclined to the horizontal.

VIRGINIUS Z. CARACRISTI.

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