US787580A

US787580A - Valve-gear.

Info

Publication number: US787580A
Application number: US21130904A
Authority: US
Inventors: Allen Loomis
Original assignee: Individual
Current assignee: Individual
Priority date: 1904-06-06
Filing date: 1904-06-06
Publication date: 1905-04-18
Anticipated expiration: 1922-04-18

Description

A. LOOMIS. VALVE GEAR.

APPLICATION FILED JUNE 6.1904.

4 SHEETS-SHEET 1.

. 4 [Ir-1 n PATENTED APR. 18, 1905.

' A. LOOMIS.

VALVE GEAR.

APPLI GATION rum) JUNE 6,1904.

4 SHEETS-SHEET 2.

No. 787,580. PATENTED APR. 18', 19 05.

' A. LOOMIS.

VALVE GEAR. 4 APPLIOATION FILED JUNE 6.1904.

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No. 787,580. PATENTED APR. 18, 1905. A. LOOMIS.

VALVE GEAR.

APPLIUATION FILED JUNE 6,1904.

4 SHEETS SHEET 4.

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Patented April 18, 1905.

PATENT OFFICE.

ALLEN LOOMIS, OF JACKSON, MICHIGAN.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No 787,580, dated April 18, 1905.

Application filed June 6, 1904. Serial No. 211.309.

T all whom it may concern.-

Be it known that I, ALLEN LooMIs, of Jackson, in the county of Jackson and State of Michigan, have invented certain new and useful Improvements in Valve-Gear, of which the following is a specification.

My invention relates to improvements in valve -gears for multiple-cylinder engines wherein the motion of each valve is derived from and compounded of the motion of two main cross-heads; and the objects of my improvements are, first, compactness; second, simplicity and reduction to the minimum of the number of wearing parts; third, to provide driving connections for the necessary pumps, and, fourth, symmetry. 1 attain these objects by the mechanism illustrated in the accompanying drawings, in which Figure 1 represents an end elevation of the forward end of an engine embodying my improvements. Fig. 2 represents a sectional elevation on line 2 2 of Fig. 8 looking toward the rear. Fig. 3 represents a sectional elevation on line 3 3 of Fig. 7 looking forward. Fig. 4 represents a sectional elevation on line 4 4 of Fig. 8 looking forward. Fig. 5 represents a longitudinal section on line 5 5 of Fig. 7. Fig. 6 is a section on line 6 6 of Fig. 8 looking forward. Fig. 7 is a top plan view of the machine with the casing removed. Fig. 8 is a side elevation with dust-case removed. Fig. 9 is a perspective view of parts 13 to 40 looking down, forward, and toward the right. Fig. 10 is an elevation of a portion of the mechanism looking toward the right.

Similar numbers refer to similar parts throughout the several views.

In the drawings, 1 2 are the driving crossheads, 3 4 the connecting-rods, and 5 6 the crank-pins.

In order that the crank-shaft be made to rotate in the direction indicated, with the linkblocks above the link-shafts and the steam and exhaust passages arranged as shown, it is essential that the right hand crank lead as shown.

9 10 are reducing-links having pivotal connection at 7 8 with the cross-heads and at 11 12 with the rocking levers.

13 14 are the rocking levers. The rockshafts on which they are formed have bearwith the rock-shafts on the opposite sides of the engine through the short

parallel links

26 and 25, respectively, so called from the fact that each is at all times parallel to a line joining the axes of the link-shaft and rock shaft upon the opposite side of the engine. The upper end of the parallel link 26 is connected to the rock-shaft 16 by the pivot 28,

which is held in the rock-shaft arm 30, formed on the rock-shaft, by means of the set-screw 32, and the lower end of the other parallel link, 25, is similarly connected to the other rockshaft, 15, by the pivot 27, which is held in the rock-shaft arm 29, formed on the rock-shaft, by means of the set-screw 31. The distance from the centers of the pivots 27 28 to the common axis of the rock-shafts 15 16 is equal to the distance from the centers of the pivots 23 24 to the axes of the corresponding linkshafts 17 18.

33 34 are the link-blocks, in halves, which are separated by and pivoted upon the rear ends of the radius-rods 35 36, the pivots being 39 and 40. The forward ends of the radius-rods are connected to the valve-stem cross-heads 43 44 by the wrist-pins 41 42.

45 46 are the head-end cylinder-ports, and 47 48 are the crank-end cylinder-ports.

101 is the reverse-shaft arm, to which the drag-blocks are pivoted at 49 50. The reverse-shaft arm is fixed upon the reverse-shaft 102 by the set-screws 103. The reversing-lever is fixed on the end of the reverse-shaft.

104 is the live-steam connection. As shown by the arrows in Fig. 7, the left-hand valve takes live steam in the middle and the righthand valve takes live steam at the ends. The former accordingly exhausts at the ends and the latter in the middle.

51 52are pins for driving the necessary pumps, such as air and boiler feed. Said pins are secured in the lugs 53 5 1, which are formed on the rock-shafts, by the set-screws 55 56. A pump 59 is shown fitted to the left-hand side, 57 being the pump connecting-rod. A blank piece 60 is shown in the right-hand pump-seat.

In operation each link-shaft, with the link and link-arm formed thereon, is translated backward and forward in unison with the cross-head on that side of the engine, though in the case of the right-hand link-shaft the direction of the motion is reversed. The path of this motion is a short circular arc the radius of which is the distance between the axes of the link and rock shafts, the chordal length of the arc being equal to the sum of both steam-laps and both leads. As the effect of this motion is the same on the valve for all grades of the link-blocks in the links, it will be referred to as the constant motion. The other component of the motion of each valve is derived from the cross-head on the opposite side of the engine, as follows: Each boxlink in which the link-blocks work is maintained at all times parallel with the opposite rocking lever by means of the parallel link connecting the link-shaft arm to the lug on the opposite rock-shaft. Thus the link oscillates about the axis of its link-shaft in unison with the oscillation of the opposite rock-shaft. As this motion has a difference of phase of one-quarter period from the constant motion of translation of the link, the cut-01f may be varied or the engine reversed by changing the grade of the link-block in the box-link, thus varying the amount of this motion which is transmitted to the valve. This is accomplished by means of the reversing lever. When a given link-shaft, as 17, is at either end of its path of translation, (the crank on that side of the engine being at one of the dead-points,) the box-link 19 is in such a position that the center of its arc coincides with the axis of the valve-stem cross-head wristpin. At such a time the valve displacement is independent of the grade of the link-block in the link, from which it follows that the valve-gear gives a constant lead. In the drawings the left-hand valve is moving forward, admitting steam to the cylinder at 4L5 and exhausting at 47, the right-hand valve has just begun to move forward the crank end of the cylinder is exhausting at 18, and steam is being admitted to the head end at 46.

Although the arrangement shown in the drawings is a preferred one, it is obvious that other arrangements may be adopted. For

instance, the rocking arms may be located between the cross-heads. Regardless of the position of the rocking arms the links may be formed on the outer ends of the link-shafts, the link-shaft arms being, as heretofore, fixed on the inner ends of the link-shafts. 1n the latter case the crossing of the link-shaft arms (best shown in the plan view) may be avoided by extending one forward and the other rearward. Drag-links pivoted to the radius-rods may be substituted for the drag-blocks. Vice versa, equivalent curved sliding-block linkages may be substituted for the red ucinglinks 9 10 or for the short

parallel links

25 and 26. By substituting side bar-links for the box-links the-drag-links or drag-blocks may be placed in the rear of the rock-shafts. Ordinary D slide-valves may be used by dividing the reverse-shaft connecting each part to one of the radius rods and providing means for moving the parts of the reverseshaft, so that one link-block is above the axis of the link-shaft when the other is below. 8%.

With this arrangement both link-shafts would be above the axis of the reverse-shafts. In order to bring the links as near together as possible, thus shortening the link-shaft arms, one slide-valve may be located forward of the other, the back of the rear valve being recessed at one side to clear the valve-stem of the forward valve.

My double valve-gear with pump connections has fewer wearingpoints than two Stephenson or two Gooch valve-gears associated with two rocking levers for driving pumps.

I am aware of Patents No. 285,286, issued to F. V. Matton on September 18, 1883; No. 331,799, issued to W. J. Lewis on December 8, 1885, and No. 524,967, issued to F. Lamplough on August 21, 1894:, all of which show valve-gears for two-cylinder engines having the cranks at right angles, wherein the motion of each valve is derived from and compounded of the motions of both main'driving crossheads. 1 therefore do not claim such a principle broadly; but

What I do claim, and desire to secure by Letters Patent, .is

1. In a valve-gear for multiple-cylinder engines, of the type wherein the motion of each valve is derived from and compounded of the reciprocatingmotion of two main driv-' ing-linkages, the combination of rock-shafts so mounted in bearings in the frame of the engine as to be free to oscillate; rocking levers fixed on the rock-shafts; driving connections to each of said rocking levers from one of the main driving-linkages; bearings fixed relatively to said rock-shafts and having axes eccentric to the axes of the rock-shafts; curved links mounted in said bearings; linkblocks free to slide upon said curved links; driving connections from each of said linkblocks to one of the valves; means for regulating the position of said link blocks upon said curved links; link-shaft arms fixed relatively to said curved links; rock-shaft arms IIO fixed relatively to the rock-shafts; and short links connecting each link-shaft arm to a rock-shaft arm which is formed upon a rockshaft other than that in which are the bearings of the link relatively to which the linkshaft arm is fixed;

2. In a valve-gear of the type described, the combination of rock-shafts free to oscillate in bearings fixed on the engine-frame: rocking levers fixed relatively to the rock-shafts; red ucing-links connecting each rocking lever to a main driving-linkage in such a manner that the reciprocating motion of the driving-linkage is reproduced in the oscillation of the rock-shaft; curved links eccentrically mounted upon the rock-shafts and free to oscillate relatively to them; link-blocks adapted to slide upon the curved links; radius-rods con-v necting the link-blocks to the valves; a reverse-shaft adapted to regulate the position of the link-blocks in the links; link-shaft arms -fixed relatively to the links; rock-shaft arms fixed relatively to the rock-shaft; and short links connecting each link-shaft arm to a rockshaft arm which is fixed relatively to a rockshaft other than that upon which are mounted the bearings about which the link-shaft arm turns.

3. In combination, in a double valve-gear of the type described, two rock-shafts; two link-shafts eccentricall y mounted upon them; a curved link and a link-shaft arm rigidly fixed upon each link-shaft; a rock-shaft arm rigidlyfixed upon each rock-shaft; short links connecting each link-shaft arm to theopposite rock-shaft; link-blocks adapted to slide upon the curved links; a reverse-shaft; means mounted upon said reverse-shaft for regulating the position of the link-blocks on the links; and driving connection from each linkblock to a valve.

4:. In combination, in a double valve-gear of the type described, two rock-shafts adapted to oscillate in fixed bearings; two sets of bearings, each having one part fixed relatively to one of said rock-shafts and eccentric to the axis of the rock-shaft; curved links rigidly mounted upon the other parts of said bearings, each being'adapted to oscillate relatively to the rock-shaft upon which it is mounted; driving connections to each curved link from the opposite rock-shaft, adapted to reproduce, in the angular motion of the link, the angular motion of said opposite rock-shaft; link-blocks adapted to slide upon said curved links; driving connection from each link-block to a valve; and means for regulating the position of the link-blocks upon the links.

5. In combination, in a valve-gear of the type described, two rock-shafts; a curved link eccentrically mounted upon each rock-shaft and adapted to oscillate relatively thereto; driving connections to each link from the opposite rock-shaft, adapted to reproduce in the link the angular motion of said opposite rockshaft; link-blocks adapted to slide upon said curved links; driving connections from each link-block to the valve which admits steam to the piston driving the rock-shaft upon which the link is eccentrical'ly mounted;- and means for regulating the position of the link-blocks upon the links. I

6. In combination, in a valve-gear of the type described, two rock-shafts supported in alinernent; curved links mounted upon said rock-shafts and adapted to oscillate relatively thereto about axes eccentric to the common axis of the rock-shafts, one having its axis above, the other below, said common axis, regarding the motion of the remote end of the radius-rods as horizontal; link-blocks adapted to slide upon said curved links; radius-rods connecting and transmitting the motion of the link-blocks to the valves; link-shaft arms fixed relatively to the curved links; rock-shaft arms fixed relatively to the rock-shafts; short links forming driving connections from each rockthereto about axes eccentric to the common axis of the rock-shafts, one having its axis above, the other below, said common axis, regarding the motion of the remote ends of the radius-rods as horizontal; link-blocks adapted to slide upon said curved links; radius-rods connecting and transmitting the motion of the link-blocks to the valves; link-shaft arms fixed relatively to the curved links; rockshaft arms fixed relatively to the rock-shafts; short links formingdriving connections from each rock-shaft arm to the arm of the opposite link-shaft; a reverseshaft; and dragblocks mounted upon the reverse-shafts for simultaneously raising or lowering the linkblocks upon the links.

8. The combination, in a valve-gear, of a rock-shaft; driving connections to the rockshaft from a main driving-linkage; a curved link 'eccentrically mounted upon said rockshaft and adapted to oscillate relatively thereto; and a link-block adapted to slide upon said curved link and having driving connections to a valve. v

9. In combination, in a double valve-gear of the type described, two rock-shafts supported in alinement; two sets of bearings, each having one part fixed relatively to one of said rock-shafts and eccentric to the axis of the rock-shaft; movable parts rigidly mounted upon the other parts of said bearings and adapted to oscillate relatively to the rockshat't upon which they are mounted; and driving connections to each of said movable parts IIO i from the opposite rock-shaft, adapted to reproduce in each of said movable parts the angular motion of the opposite rock-shaft.

10. In combination, in a valve-gear of the type described, two rock-shafts; two sets of bearings, each having one part fixed relatively to one of said rock-shafts and eccentric to the axis of the rock-shaft; curved links rigidly mounted upon the other parts of. said bearings and adapted to oscillate relatively to the rockshafts; and link-blocks adapted to slide upon said curved links.

11. In a valve-gear, two rock-shafts supported in alinement, a movable part eccentrically mounted upon one of the rock-shafts and adapted to oscillate relatively thereto, and driving connection between the other rock-shaft and said movable part, adapted to reproduce-in the one the angular motion of the other, independently of the angular motion of the rock-shaft upon which the movable part is mounted.

12. In a valve-gear, a rock-shaft, a link mounted rotatably in said rock-shaft at one side of the axis thereof, means for oscillating the rock-shaft, means to oscillate said link relatively to the rock-shaft, and driving connections from said link to a valve.

13. In a valve-gear for an engine having a plurality of independently-operated pistons, a link, connections between one of the pistons and the link whereby the link is given a motion bodily of translation, connections between another piston and the link whereby the latter is oscillated, the connections be tween the several pistons and the link, whereby such motions of translation and oscillation are imparted to the link, being wholly independent of each other, and driving connections from said link to a valve.

14. In a valve-gear for an engine having a plurality of independently-operated pistons, an oscillatory member connected to one of the pistons in such manner as to be oscillated directly and exclusively by the movement of said piston, a link mounted rotatahly with reference to said oscillatory member and connected thereto in such manner as to be-moved bodily by the oscillations thereof, connections between said link and another piston whereby movement of the piston oscillates the link, and connections between the link and a valve.

In testimony whereof I have afiixed my signature in presence of two witnesses.

ALLEN LOOMI'S.

Witnesses:

FRANCIS B. DAVIS, BESSIE SHARP.