US825980A - Automatic cut-off for reversible engines. - Google Patents

Description

N9. 825,980. PATENTED JULY1'7, 1906. G. L. PIBURN. AUTOMATIC GUT-OPP FOR REVERSIBLE ENGINES.

APPLICATION FILED 00T.27, 1905.

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PATENTED JULY 17 G. L. PIBURN. AUTOMATIC OUT-OPP FOR REVERSIBLE ENGINES.

APPLICATION FILED 00127, 1905.

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UNITED STATES PATENT OFFICE.

GRANT L. PIBURN, OF GALLA'IIN TOWNSHIP, CLAY COUNTY, MISSOURI, ASSIGNOR OF ONE-HALF TO WVILKIE WV. WARREN, OF CLAY COUNTY,

MISSOURI.

AUTOMATIC CUT-OFF FOR REVERSIBLE ENGINES- Specification of Letters Patent.

Patented July 1'7, 1906.

Application filed October 27, 1905- Serial No. 284,603.

To all whmn it may concern.-

Be it known that I, GRANT L. PIBURN, a citizen of the United States, residing in Gallatin township, in the county of Clay and State of Missouri, have invented certain new and useful Improvements in Automatic Cut- Offs for Reversible Engines, of which the fol lowing is a specification.

This invention relates to automatic cut-offs for reversible engines, and has for its object to produce a reversible engine equipped with cut-off mechanism which operates automatically, efficiently, and reliably.

A further object is to produce cut-off mechanism which can be applied at comparatively small expense to reversible engines now in use.

The advantages of an engine of the character named equipped with my improved cutofl are as follows: economy in the use of fuel and steam, simplicity of construction, ease of handling, and cheapness of repair.

I/Vith these objects in view and others, as hereinafter appear, the invention consists in certain novel and peculiar features of construction and organization, as hereinafter described and claimed, and in order that it may be fully understood reference is to be had to the accompanying drawings, in which Figure 1 is a central vertical longitudinal section of an engine-cylinder and steamchest equipped with cut-off mechanism embodying my invention. Fig. 2 is a section on the line II II of Fig. 1. Fig. 3 is an end view of one of the elements of the cut-off mechanism. Fig. 4 is a side view of the same. Fig. 5 is a view of a modified construction, the same being a vertical section on the line V V of Fig. 6 with the dial-casing in the background, shown in vertical longitudinal section. Fig. 6 is a section taken on the line VI VI of Fig. 5. Fig. 7 is a view of a second modification, the same being a section similar to Fig. 5, except that the valve-casing in the background is shown in elevation. Fig. 8 is an end View of one of the cut-off elements and of a part of the mechanism for operating the same.

In the said drawings, 1 indicates an engine-cylinder of the type shown or of any other suitable or preferred type, and 2 is the piston therein. 3 indicates the steanr-chest of any preferred type, and 4 the cylindrical valve-casing therein, said casing being provided, by preference,with a horizontally-arranged frustum-shaped lining 5, provided with ports 6 and 7, adapted to act alternately as supply and exhaust ports, and with an exhaust-port 8. The ports 6 and? register, respectively, with the ports 9 and 10, leading to opposite ends of the cylinder, and port 8 registers with the usual exhaust-port 11.

The passage of the lining 12 between ports 6 and 7 is of reduced diameter, and in the large ends of said passage the lining is provided with threads 13 and 14, one being a left-hand and the other a right-hand thread.

The cut-off elements are in the form of rings which fit closely in the lar e ends of the lining-passage, one of the cut-0F elements 15 fitting in one end and having a thread 16 engaging thread 13 and the other 17 having an opposite thread 18, engaging thread 14, so that when said rings are rotatably moved in the same direction they will simultaneously move inward or outward, as the case may be. 19 indicates the usual double-end pistonvalve, the same being adapted to engage with a steam-tight relation the reduced portion of the lining-passage and the inner sides of the rings 15 and 17, though said piston is not always in engagement with said rings at the same time, as shown.

In the construction shown in Fig. 1 each ring is provided with a bifurcated arm or fork 20, engaging wide cams 21, secured rigidly on shaft 22, said shaft being preferably step-jointed at one end, as at 23, in the steamchest and journaled in a stufling-box 24;, mounted in the other end of the steam-chest. The preferred means of securing the cams rigidly on shaft 22 is to provide-them with sleeve extensions engaged by set-screws 25, which are adapted to impinge on said shaft, and longitudinal movement of the shaft in one direction is prevented by the collar 26, clamped thereon and abutting against the end of the stufling-box 24.

The shaft 22 is ada ted to be geared to the governor (not shown of the engine in any suitable or preferred manner, so that as the speed of the engine increases or falls said shaft shall be turned and consequently turn the cut-off rings and cause them to move inward or outward so as to contract or expand the space between their inner ends and the ends of the central portion of the lining, the result being a contraction or expansion, as the case may be, of orts 6 and 7, registering with said space, as s own clearly in Fig. 1.. This ad 'ustment of the cut-off rings obviously occurs without interfering in any respect with the reciprocatory action of the piston-valve 19. In Fig. 5 the cut-0H rings are of modified type and the means for adjusting them is also different from that shown on Sheet 1. In said figure the cut-off rings corresponding to rings 16 and 17 are numbered 27 and 28, respectively, and 'diifer therefrom in being of greater proportionate len th and provided near their inner ends wit slots 29, which extend almost completely around the rings and are somewhat narrower than the ports 6 and 7 with which they register, this arrangement leaving only a small neck portion 30 between the ends of the slots. In this type also it is preferred that the lining shall be of uniform internal diameter, and because of the fact that a portion of each ring is disposedin- Ward of ports 6 and 7 the piston need never be wholly Withdrawn from engagement with either ring, and therefore bears a steam-tight relation with the rings only and not directly with the lining. The cut-off rings 27 and 28 have opposite threaded relations with the lining, as in Sheet 1, and are provided at their ends with outwardly-projecting longitudinally-slotted arms 31 instead of with bifurcated arms or forks 20, and engaging said slots is a rod 32,headed at both ends and of greater. length than the distance between the outer ends of the rings when occupying the outer extremity of their adjustment. This rod 32 is connected to the lower end of the reciprocatory rod 33, adapted to slide in the stuffing-box 34 and be reciprocated through the instrumentality of a suitable overnor, (not shown,) the reciprocation of t e rod as the speed of the engine increases or diminishes effecting the adjustment inward or outward of the cut-ofi rings. In Fig. 7 in lieu of the rod 32 engaging the arms of both cut-off rings and of slotting said arms I provide each of said arms with a rigid pin 35, engaging horizontally-slotted feet 36, secured to the lower ends of rods 37, mounted in stufling-boxes 38 and connected at their upper ends bya cross-head 39, secured rigidly to the lower end of a rod 10, corresponding to rod 33 and adapted to be reciprocated by the governor for the purpose of adjusting the cutoff rings inward or outward. Referring first to the operation of the mechanism disclosed by Sheet 1., it will be apparent, assuming that the steam is cut off when the cylinder-piston has made one=half its stroke, that a sudden increase in the speed of the engine will through the instrumentality of the governor and the connections described move the cutoif rings inward, and therefore cover more or less of the ports 6 and 7,which action diminishes the live-steam lead. As a result the steam is cut off earlier in the stroke of the main piston and the power is reduced in proportion to the reduction of the load on the engine. Should the load on the engine increase, the speed of the governor of course falls and as a result reverses the adjustment of the cut-off rings in order that the space between their inner ends and the inner portion of the valve-casing lining shall be at the most equal in width to the width of said ports. This reverse adjustment of the cutoif rings increases the live-steamlead and causes the piston-valve to cut 0H the steam later in the stroke of the piston. It will further be seen that the automatic adjustment of the cut-off rings to suit the load results in an economy in the use of fuel and steam, as is true in the ordinary automatic cut-off engine. It will also be noticed that where the speed of the engine falls suddenly, and therefore results, as described, in expanding ports 6 and 7, and thereby increases the lead, back pressure on the cylinder-piston would be reduced, because the steam would escape through a larger passage than that through which it entered. It is to be understood, however, that the exhaust compression or lead remains constant, which, it is believed,

has never been accomplished in an automatic engine provided with a single valve, as heretofore all single-valve automatic engines vary the exhaust compression or lead to the best of my knowledge and belief.

The operation of the cut-off rings of the type shown on Sheet 2 is the same as in the other type; but because of the fact that the slots 29 are narrower than the ports 6 and 7 the steam will be cut off earlier, which gives the same effect as increased lap. Furthermore, with this type the exhaust compression or lead is changed. This form, however, has an advantage over the first, in the respect that it would give an earlier release when cutting off earlier in the stroke and there would be less back pressure on the cylinderpiston.

Either type of construction can be used advantageously with reversible engines, though it is to be understood that they can be used on any engine havin a piston-valve.

From the above escription it will be apparent that I have produced an automatic cut-off for single-valve reversible engines which embodies the features of advantage enumerated as desirable and in addition thereto the desirable features of simplicity,

passage of steam to and from the cylinder, a pair of cut-off rings surrounding said valve outward of the ports which alternately supply the cylinder with steam, and means to move the rings toward or from each other and thereby cut off the supply of steam to the cylinder earlier or later as the case may be, than before such adjustment occurred.

2. In a reversible engine provided with a reciprocatorypiston-valve to control the passage of steam to and from the cylinder, a pair of cut-off r'ngs surrounding said valve outward of the ports which alternately supply the cylinder with steam, having a threaded relation with the valve-casing, and means for turning the rings and thereby causing them to move toward or from each other and thus cut off the supply of steam to the cylinder eariler or later as the case may be than before such adjustment occurred.

3. In a reversible engine, a valve-casing within the steam-chest, a lining in said casing, supply-ports in permanent communication with the ports for alternately conducting steam to and away from the cylinder, rings within the lining, means for moving the rings toward or from each other as the speed of the engine fluctuates so as to cover and therefore narrow more or less the ports of the lining in communication with said steamconducting ports of the cylinder, a doubleheaded piston in said rings, and means for reciprocating said piston.

4. In a reversible engine, a valve-casing within the steam-chest, a lining in said casing, supply-ports in permanent communication with the ports for alternately conducting steam to and away from the cylinder, rings within the lining, and having a threaded relation therewith, means for turning said rings as the speed of the engine fluctuates, a double-headed piston in said rings, and means for reciprocating said piston.

5. In a reversible engine provided with a piston-valve, the combination of a lining for the piston-valve casing having the inner portions of its passage enlc rged from a point ust inward of the end ports leading from the piston-valve casing to the cylinder and provided with ports registering with the firstnamed ports, a pair of cut-off rings fitting with a steam-tight relation in the enlar ed portions of the lining-passage and adjustable longitudinally therein and means for causing said cut-off rings to partially cover or uncover said ports accordin ly as the load on the engine is increased or diminished.

6. In a reversible engine provided with a piston-valve, the combination of a lining for the piston-valve casing having the inner por tions of its passage enlarged from a point just inward of the end ports leading from the piston-valve casing to the cylinder and provided with ports registering with the firstnamed ports, a pair of cut-off rings fittin with a steam-tight relation in the enlarge portionsof the lining-passage and adjustable longitudinally therein and having a threaded relation with the piston-valve casing, and means for turning said rings to cause them to move toward or from each other accordingly as the load on the engine and consequently its speed increases or diminishes.

7. In a reversible engine provided with a piston-valve, the combination of a pair of cut-off rings to vary the area of the end ports leading to and from the cylinder and having a threaded relation with the piston-valve casing, arms projecting from said cut-off rings, and means for rocking said arms so as to move said cut-off rings toward each other when the speed of the engine increases and in the opposite direction when the speed of the engine falls.

8. In a reversible engine provided with a piston-valve, the combination of a pair of cut-off rings to vary the area of the end ports leading to and from the cylinder and having a threaded relation with the piston-valve casing, bifurcated arms or forks projecting from said cut-off rings, a shaft suitably journaled and adapted to turn in one direction or the other as the speed of the engine increases or falls, and eccentrics mounted on said shaft and engaging said bifurcated arms or forks and bearing a sliding relation thereto.

In testimony whereof I affix my signature in the presence of two winesses.

GRANT L. PIBURN. Witnesses:

H. C. Rononns, G. Y. THORPE.

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