US2189471A - Reversible propulsion unit - Google Patents

Description

Feb. 6, 1940. J McGREW REVERSIBLE PROPULSION UNIT Original Filed May 16, 1935 4 Sheets-Sheet .l

J. A. M GREW REVERSIBLE PROPULSION UNIT Feb. 6, 1940.

4 Sheets-Sheet 2 Original Filed May 16, 1935 Feb. 6, 1940. J. A. MQGREW REVERSIBLE PROPULSION UNIT Original Filed May 16, 1935 4 Sheets-Sheet 3 Feb. 6, 1940. J. A. M GREW REVERSIBLE PROPULSION UNIT Original Filed May 16, 1935 4 Sheets-Sheet 4 Patented Feb. 6, 1940 uni-reosrrss REVERSIBLE PROPULSION UNIT John- A. McGrew, Albany, N. Y.

Original" application May 16, 1935,v Serial No. 21,855; new Patent No. 2,078,262, dated April 27,

1937. 1937,. Serial? No. 134,441

Divided and this application April 1,

' "9 Claims. (01. 121-439) This invention relates to propulsion units: of the type employed to propel, or to assist in propelling, railroad rolling stock.

k In my pending application Serial 21,855, filed 'May 16, 1935, now Patent No. 2,078,262, dated- April27, 1937, of which the present application is a division, is disclosed a locomotive embodying a plurality of individual driving units adapted to be selectively energized. The locomotive is reversible and each of the individual propulsion units is reversible, each such unit being provided with a, novel valve reversing means. This valve reversing means is particularly adapted for use in propulsion units of the type disclosed in said application, in which the various operating parts must be positioned in a very small space, and in which the valve cut-01f is fixed. It embodies a novel arrangement of elements designed, and mounted within the casing of the propulsion unit, in such manner that ready reversal of the unit can be'efiected without: interfering with the normal functioning of the unit. It will be appreciated that minor changes may be made in the design of the several elements 5" of the novel valve reversing; mechanism and; that the embodiment illustrated in the accompanying drawings is set forth by way of example only:

In the drawings:

Figure 1 is a plan View of the propulsionv unit;

30, .portion of the cover plate being broken away to disclose certain of the operating parts thereof"; Figures 2, 3 and 4, are longitudinal sections through the unit taken, respectively, on lines 2'2, 3+3, and 4-4 of Figure 1; Figure 5 is a section on line 5-5 of Figure,2; Figure 6 shows in side elevation a portion, of

the novel valve reversing mechanism- Figure 7 is a similar view but showing the parts thereof in different positions; and

Figure 8 is a plan View of this mechanism. The frame of the propulsion unit is indicated at It in Figures 1 to 4 inclusive and it willbe understood that this frame may be formed in 7 various ways, although I prefer to form it as one integral casting which, includes the various bearings for the rotatable elements of the mech-. anism as well as the various steam passages and cylinders. A cover is indicatedv at H, this cover being detachably secured to the frame and serving to protect the operating parts of the unit as well as to prevent the escape of lubricating oil, of which a quantity is always maintained within the casing.

The propulsion unit is mainly supported upon the axle l 2, the frame being provided with spaced bearings B for thereception of the axle. Each such bearing comprises a half portion I3 which only be said herethat the driving gear is automatically connected to the axle when positively rotated in either direction-about the axle and is automatically disconnected from the axle when the unit is deenergized while theaxle is rotating.

Disposed parallel to axle I2 is a crankshaft ll suitably mounted in bearings B, similar to bearings 'B but somewhat smaller. Fixed on crank shaft ll'is a driving pinion W the teeth of which mesh with the teeth of driving gear M at all times. Crankshaft H is driven by. means of steam actuated pistons through the usual piston rod, crosshead and connecting rod mechanisms, which are or may be conventional in form and need not be described. The cylinders within which the crank shaft driving pistons work are indicated at ill in Figure 1, and the passage of steam into and out of each of these cylinders is controlled by a cylindrical slide valve, one of which isindicated at 29 in Figures 2 and 4, each. valve reciprocating within a cylindrical valve-cage 2|.

Associated with each valve is a valve stem,

[one of which is indicated at 22 in- Figure 2, and

each valve stem is connected by: means of a link to the lower end. of a rocker which is in turn rotatably supported at its midpoint upon an arbor projecting laterally from: the cap 23' of one of the bearings B, the. valve stem, 22, shown in Figure 2' being connected by link M to the lower formed in the upper ends of pedestals 3! which comprise bracket-like extensions of the removable caps of main crankshaft bearings B.

As shown in Figures 1 and 5, there is: fixed upon the opposite end of eccentric crank shaft '30 a'second crank arm 32, disposed at an angle of approximately 90 to the crank arm 29. The outer end of crank 32 is connected to a slide valve 33 by means of eccentric rod 34, rocker 35, link 36 and valve stem 31'. From this it follows that rotation of shaft results in simultaneous sliding movements of the two valves, the valves being, however, in different phase, as is usual. Eccentric shaft 38 is driven from the driving pinion l8 through a spur gear 40, in constant mesh with driving pinion I8, and through an adjusting mechanism now to be described.

It will be seen (Figure 5) that spur gear 40 rigidly secured upon a sleeve 4| which is in turn freely rotatable upon shaft 30, ball bearings being preferably interposed between the sleeve and shaft. The inner end of sleeve 4| is enlarged and toothed so that this portion of the sleeve comprises a bevel gear, indicated at 42. A similarly formed but oppositely facing bevel gear 43 is keyed to shaft 30 and operatively connecting gears 42 and 43 is a third gear 44 which is rotatably mounted upon a trunnion member 45 disposed radially with respect to shaft 38 and the inner end of which is rigidly secured to and preferably formed integrally with a sleeve mounted upon shaft 36 intermediate gears 42 and 43, roller bearings being preferably interposed between the sleeve and shaft so that free relative rotation is assured.

W'hen trunnion 45 is supported against movement circumferentially about shaft 30 rotation of gear 42 will be communicated to gear 43 through gear 44, gears 42 and 43 rotating at equal angular velocities but in opposite direc- 'tions so that shaft 3!! is rotated in a direction opposite to that in which gear 40 is rotated, but in the same direction as that in which the driving pinion I8 rotates. In the operation of the device the trunnion 45 will occupy and be definitely supported in either one or the other of two positions, in one of which positions the valves are so timed with respect to each other in their movements that the motor will drive the associated axle in one direction, and in the other of which positions the relationship of the valves is so changed that the operation of the motor will be reversed. In Figures 6 and '7 the two positions of trunnion 45, i. e., for forward and reverse motor operation, respectively, are illustrated.

For conveniently moving gear 44 from one position to the other, an air pressure operated device is employed. This device comprises essentially a cylinder 50, one end of which is pivotally connected at 5| to a bracket-like projection 52 extending upwardly from one of the main frame axle bearing caps |4 (Figure 4). Within this cylinder is a piston 53 having a piston rod 54 projecting through the end wall thereof, the outer end of this piston rod being pivotally connected to a lever 55 mounted upon a transversely extending shaft 56 supported in spaced bearings 5! fixed upon the main crank shaft bearing caps, shaft 56 being hereinafter designated the reverse shaft. Also rigid with shaft 56 is an arm 58, the upper end of which is connected by means of a link 59 to a lateral extension of sleeve 46 upon which the trunnion is fixed.

Suitable ports are formed in the wall of cylinder 5|}, at opposite ends thereof, and fluid supply lines are provided for bringing fluid under pressure, for instance air, from a distant source to either end of the cylinder and permitting fluid on the opposite side of the piston to escape from the cylinder, thus making it possible to main- "tain the piston at either end of its stroke. Due

to a slight rocking movement of the cylinder in effecting reversal of the mechanism just described, the air lines 62 and 63 are made flexible. They pass through suitably formed apertures in the cover plate of the motor unit and to a distant control means.

In Figures 6 and 7, showing the gear 44 in both of its extreme positions of adjustment, the relative positions of the eccentric crank arms are illustrated and it will be perceived that in the movement of gear 44 from the position in which it is illustrated in Figure 6 to the position in which it is shown in Figure 7, the crank arm 29 has been moved approximately 100 in a clockwise direction, the other crank arm having likewise been moved through the same angle and in the same direction. The shifting of the angular positions of the eccentric crank arms effects the shifting of the relative positions of the valves to effect reversal of the motor and, by means of the reversing cylinder and mechanism just described such reversal may be accomplished with great case.

It is of course apparent that as the sleeve 46 and trunnions 45, together with the gear 44, are moved about the axis of the eccentric shaft by the means and in the manner just described, the change in angular positions of the eccentric arms results from rotation of the eccentric shaft 30. The gear 42 remains stationary during reversal, being locked in position by pinion I8, which is in turn prevented from revolving because in constant mesh with the driving gear l6. Hence the gear 44 rolls on gear 42 as the angularity of trunnion 45 is changed and gear 43 and shaft 30 are caused to revolve through angles twice as great as that through which the trunnion 45 moves in passing from one extreme position to the other. The mechanism is so designed that the axis of trunnion 45 moves through an angle of approximately 50 in effecting reversal and hence shaft 30 and the eccentric crank arms on its ends are caused to revolve through angles of approximately 100. For limiting the angular movements of the reverse shaft 56 positive stop means is provided, including a member 56 fixed on shaft 56, and preferably integral therewith, and abutment members 65 supported upon the cap of one of bearings B. Preferably the abutment members are threaded bolts provided with lock nuts in order that the permissible rotatory movement of the reverse shaft may be nicely regulated. The valve mechanism illustrated embodies no means for varying the cut-off of the valves, which is fixed so as to provide for maximum expansion of the steam entering the cylinders.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A reversible propulsion unit comprising in combination, a frame having bearings for a driven axle, bearings for a driving shaft, and valves and valve cages, spaced horizontally from and upon one side of said axle bearings, eccentric and reverse shaft-s supported upon said driving axle bearings, means operatively connecting the eccentric and reverse shafts, and means opera tively connecting the eccentric shaft to the valves.

2. The combination set forth in claim 1 in which a power operated device is positioned above and is operatively connected to the reverse shaft. 3. A reversible propulsion unit comprising in combination, a frame having bearings for a driven axle, bearings for a driving shaft, and valves and valve cages, spaced horizontally from and upon one side of said axle bearings, eccentric and reverse shafts, supported upon said driving axle bearings, means operatively connecting the eccentric and reverse shafts, means operatively connecting the eccentric shaft to the valves, and a power device for rocking the reverse shaft, said device having one part pivotally connected to a bearing for the driven axle and a second part pivotally connected to said reverse shaft.

4. A reversible propulsion unit comprising in combination, a. frame having bearings for a driven axle,bearings for a driving shaft, and valves and valve cages, spaced horizontally from and upon one side of said axle bearings, eccentric and reverse shafts supported upon said driving axle bearings, means operatively connecting the eccentric and reverse shafts, means operatively connecting the eccentric shaft to the valves, and a power device for rocking the reverse shaft, said device comprising a piston and cylinder, the piston being pivotally connected to the reverse shaft and the cylinder pivotally connected to an axle bearing.

5. In a reversible propulsion unit, in combination, a steam actuated motor having control valves, a shaft to bedriven, a driving shaft parallel to and horizontally spaced from said first shaft and ioperatively connected thereto, the driven shaft being intermediate the motor and driving shaft, an eccentric shaft operatively connected to one of said first mentioned shafts, said eccentric and driven shafts being horizontally spaced and said driving shaft being intermediate said eccentric and driven shafts, and mechanism connecting said eccentric shaft and valves, said mechanism comprising a rocker member mounted for rockingmovement about an axis parallel to and intermediate said driving and driven shafts, and having a part overlying the driving shaft and a part intermediate the driving and driven shafts.

6. The combination set forth in claim 5 in which the driving shaft is belowthe eccentric shaft, the eccentric shaft being supported upon the driving shaft bearings and said mechanism having an operating part extending between the driving and driven shafts.

'7. In a reversible propulsion unit in combination, a frame, a driving motor provided with control valves, a driven shaft, bearings in said frame for said shaft, a gear on said shaft, a driving shaft disposed parallel with said driven shaft, bearings in said frame for said driving shaft, an eccentric shaft rotatably mounted upon the driving shaft bearings and spaced horizontally from said driving shaft upon the side thereof opposite to said driven shaft, connections between said eccentric shaft and said valves, a plurality of intermeshingv gears connecting the eccentric shaft and said driven gear, said intermeshing gears including two spaced gears adapted for parallel rotation about a common axis and an intermediate gear intermeshing with said spaced gears and mounted for oscillation about the axis of said spaced gears, and means for oscillating said intermediate gear to vary the phase relationship of said spaced gears.

8. In a reversible propulsion unit in combination, a frame, a driving motor provided with control valves, a driven shaft, bearings in said frame for said shaft, a gear on said shaft, a driving shaft disposed parallel with said driven shaft, hearings in said frame for said driving shaft, an eccentric shaft rotatably mounted upon the driving shaft bearings and spaced horizontally from said driving shaft upon the side thereof opposite to said driven shaft, connections between said eccentric shaft and said valves, a plurality of intermeshing gears connecting the eccentric shaft and said driven gear, said intermeshing gears including two spaced gears adapted for parallel rotation about a common'axis and an intermediate gear intermeshing with said spaced gears and mounted for oscillation about the axis of said spaced gears, and means for oscillating said intermediate gear to vary the phase relationship of said spaced gears, said last named means comprising a power actuating device supported by said driven shaft bearing and disposed insaid motor, an eccentric shaft supported upon said driving axle bearings, means operatively connecting the eccentric shaft to the valves, and

a power device for adjusting said eccentric shaft to effect reversal of said motor, said power device being supported upon said axle bearing and operatively connected with said eccentric shaft.

JOHN A. MCGREW.

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