US1780329A - Reversing-gear mechanism - Google Patents

Description

Nov. 4, 1930. F. N. BAR D REVERSING GEAR MECHANISM 2 Sheets-Sheet 1 Filed Nov. 28, 1921 jzverzr'.

Nov. 4, 1930. F BARD 1,780,329

REVERSING GEAR MECHANISM Filed No r. 2 1921 2 Sheets-Sheet 2 Patented Nov. 4, 1930 PATENT OFFICE FRANCIS N. BARD, 01" HIGHLAND PARK, ILLINOIS REVERSING-GEAR MECHANISM Original application filed July 31, 1920, Serial No. 400,478. Divided and this application filed November The present invention relates in general to reversing gear mechanism and more particularly to mechanism of the character referred to operable by mechanical power, and

5 has special reference to the provision of an improved form of fluid pressure driven reversing gear mechanism.

The principal objects of the, present invention are the provision of an improved .10 form of fluid-operated reversing gear mechanism; the provision of an improved gearing, and more particularly, irreversible gearing, for establishing a driving connection between a suitably driven element and the mechanism to be moved thereby; the provision of an improved valve mechanism for controlling the flow of fluid to the parts to be actuated; the provision in general of an improved arrange ment of motion transmitting elements, and more especially one adapted for operating a controlling valve; the provision of a power driven reversing gear mechanism of means whereby the mechanism may be actuated manually from an external point in the defeet of power actuation; the provision of .means for providing an auxiliary or supplemental source of power for actuating the reversing gear mechanism, in certain contingencies, and of automatically acting controlling mechanism therefor; together with such further and additional objects as may be below set forth. 7

Mechanisms of the character referred to have a general field of usefulness, and are of particular utility in the operation of the valve mechanism of large steam engines.

This application is a division of my application, Serial No. 400,47 8.

For purposes of illustration, therefore, the inventions have been shown structurally embodied in form adapted for employement as gearing for opening and closing, and for reversing, the valve mechanism of railway locomotive engines.

In the accompanying drawings, therefore- Figures 1 and 2 are respectively a longitudinal elevational view, and a top plan view, of the casings of the improved mechanisms, together with the associated elements extend- Serial No. 518,426.

ing respectively to the engineers cab and to the tumbling shaft of the locomotive;

Figure 3 is a longitudinal sectional view, taken substantially centrally of the device of Figure 2, on the line 3-3 thereof;

Figure 4 is a plan view, partly in section, illustrative of certain elements indicated in side elevation in Figure 3 taken on line ll of Figure 3;

Figure 5 is an enlarged fragmentary elevational view,'partly in section, of certain details of the construction of Figure l, illustrative of other relations assumed bycertain of the parts; and

Figures 6, 7 and 8 are fragmentary sectional views illustrative of details of construction and arrangements of ports and passages, such views being taken on lines 6-6, 7-7, and 88 of Figure 5.

Referring first to Figures 1 to 3 of the drawings, it will be observed that in the present invention there is provided a casing structure, 10, having cylinder portions 11,12,within which is mounted a piston structure including heads 18, 14, connected by a rod 15. The casing, 10, is preferably made integral with the cylinder portions in alignment and is provided with an integral lateral extension to form a housing, 19, for certain gearing elements hereinafter to be described.

The rod, 15,is non-circular and is supported in the casing, 10, by means of a step-bearing, 16, which also serves as a bearing for the reduced shaft, 17, of the spiral worm, 18, mounted in said housing, 19.

The worm is held in position in the housing, 19, and against longitudinal movement by means of bushing, 20, and is in mesh with a segmental rack, 21, carried on a shaft, 22, in a housing, 23.

Reverting to the shaft, 17 and the rod, 15,.

these two elements have a rack-and-pinion engagement, (see Figure 4) and clearly the length of the rack on the rod, 15, and the re 'lationship of the number of teeth on the rack to those on the pinion is such that the full throw of the rack-rod, 15, will cause a number of revolutions of the spiral gear, 18.

As a result of this plural rotation of the spiralgear, the turns of the worm, 18. can

be quite closely approximated, thus producing a more eflicient locking eifect against reversing by the segment, 21, without increasing the angular throw of the segment.

As means for the operation of the piston structure, there are formed within the casing the passages 31 and 32 for the purpose of admitting and exhausting fluid under pressure to and from the opposite ends of the casing structure. This admission and exhaustion of fluid is controlled by a valve mechanism shown generally at 33 in Figures 5 and 8.

The said controlling valve structure comprises a valve chamber, 34, with which the passages 31 and 32 communicate. This valve chamber is formed by securing a cup-shaped block, 30, to the casing 10, by means of screws, 29, (see Figure 7).

Fluid under pressure is introduced into the chamber 34 by means of a pipe, 35, connected to a suitable source of supply (not shown) and controlled by a cab-valve under the hand of the engineer. From the chamber, 34, exhausted fluid is vented to the atmosphere at the point indicated at 36 (Figure 7).

For establishing the desired communications between the various passages and ports, there is employed a suitable valve disposed in the chamber 34. This valve is conveniently one of the rotating segmental disc type, 37, provided with a segmental groove, 38.

It will be apparent from viewing Figure 5 of the drawing that the contour of the disc, 37 is such that the orifices of both of the passages 31 and 32 are covered in one position of the disc, 37, hereinafter referred to as lap .position and whenever the disc, 37, is moved in either direction from such lap position, the groove, 38, will bring one of the passages 31, 32 into register with the passage leading to the exhaust port, 36, (see Figure 7), and at the same time uncover the orifice of the other of such passages and permit the influx of fluid under pressure, thus insuring at all times an equilibrium of pressure against the several piston heads and permitting the valve gear to be set at any desired cut-ofl and held against creeping. It will be readily seen that all of the desired functions of the controlling valve mechanism are accomplished by the use of but a single moving valve member.

As means for operating the valve mechanism, that is, for turning the disc, 37, to any desired extent, there is employed a link, 39, fixed on the stem, 40, of the valve 37. Such link is pivotally connected by a rod, 41, to one arm, 42, of a bell-crank lever, 43, in turn pivoted to an annulus, 44, surrounding the shaft, 22. The so-called short reach rod 47 is pivotally connected as indicated at 45 to the arm, 46, extending from the annulus, 44.

From the foregoing description, it will be understood that by manipulation of this lever and thereby movement of the short reach rod 47, the engineer can move the disc, 37,

into any desired position, and thereby not only impart such forward or reverse movement to the locomotive as may be desired, but also set and hold the valve gear at any desired cut-ofi'..

For the purpose ofvrestoring the valve, 37, from any off-lap position to lap position, after imparting the necessary movement to the piston rod, 15, and associated parts and thereby holding the valve gear at the desired cut-ofl, the arm, 48, of the bell-crank lever, 43, has a lost motion connection by the pin and slot arrangement, 50, with the lug, 52, projecting from the annular portion, 54, of the lever, 49, pivotally connected at its lower end to the so-called long reach rod 51, as is clearly to be seen on inspection of Figure 5.

As is obvious on viewing Figures 3 and 5 when the valve, 37, is moved to an off-lap position, as for example as shown in Figure 5 where the left-hand end of the groove, 38, is in communication with the passage, 31, and the right-hand end of such groove terminates at the point indicated at 38*, the shaft will be oscillated as hereinbefore clearly set forth and will in turn actuate the long reach rod 51 through the lever, 49.

This movement of the lever, 49, will in turn actuate the bell-crank lever, 43, through the pin and slot connection, 50, and move said lever, 43, to the position indicated in dotted lines in Figure 5, thus restoring the valve, 37, to lap position.

Inasmuch as at times'circumstances may arise, owing to breakage or stoppage of one of the fluid conducting lines or passages or failure of fluid supply, or the piston structure may for other reasons become inoperable by fluid pressure, which may render it desirable to operate the piston structure manually in order to set the valve gear in a predetermined position, I extend the shaft, 17, through and beyond the casing, 10, and provide it with a squared terminal, 55, adapted for the application of any suitable means, such as a wrench, whereby it may be manually rotated or by any available mechanism.

Having thus described my ,invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is- .1. In a reverse gear operating mechanism, a fluid operated motor including a cylinder, a piston operating in said cylinder, a rack bar connected to said piston and extending without the cylinder, a worm arranged with its axis transversely of said rack bar and operated thereby, means connected to the reverse gear for receiving motion from said worm, a casing for said worm, said means and said rack bar and forming a substantially common bearing for the rack bar, and worm, and an extension from said worm through said casing whereby the mechanism may be manually operated.

2. In a reversing gear mechanism in com- 1,7so,see

bination, a fluid pressure reciprocating power operated mechanism for operating the reverse gear connecting member comprising a rack bar, a piston for actuating said rack bar,

a, segment connected to said connecting memher, a worm for moving said segment disposed in a lane angularly related to said rack bar in a aterally extending casing portion, said worm having an extension connecting same to said rack bar, a common removable bearing for said rack bar and extension, said bearing being retained in position by the relative position of said rack bar and extension.

In testimony whereof I have hereunto signed my name.

' FRANCIS BARD.

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