US1637909A - Bolt-type emergency governor - Google Patents

Description

Aug. 2, 1927.

F. c. LINN- Bom EEPE EMERGENCY GOVERNOR Filed Oct. 20, 1924 Patented Aug. 2, 1927.

UNITED STATES PATENT`=FFICE- FRANK C. mm1, or LYNN; MASSACHUSETTS, Assrenoa To GENERAL ELECTRIC vCoivr- PANY, A CORPORATION or N-Ew'YoR-K. c

BOLT-TYPE EMERGENCY GOVERNOR.

The present invention relates to emergency lgovernors sii-c h as are used ink connection with; elastic fluid turbines, for example, to effect the closing of the emergency control valve means in case of excessy speed. It relates especially to emergency governors of the bolt type wherein a bolt or plunger, the center of gravity of which .is at oney side of the center of` the shaft, is held against movel0 mentnormally by a spring butin case of excess. speed is thrown out by centrifugal force and, strikes a trip finger orV trigger which, when moved, releases the emergency valve mechanism and permits it to close.

In connection with such governors, Considerable difficulty has been experienced due to the bolt or plunger damaging or breaking the trip finger for, as will be appreciated, in the case of a shaft ruiming at high speed, the head of the bolt or plunger strikes the trip linger with considerable force.

'Ilie object of the present invention is to provide an improved form lof trip finger whereby the above referred to difficulty is overcome and for a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawing, Fig. 1 is a view, partly in section of an emergency governor mechanism embodying my invention, and Fig. 2 is a diagram.

Referring to the drawing, 1 indicates a shaft, for example, the shaft of an elastic fluid turbine. Mounted in a transverse opening 2 in the shaft is a bolt or plunger 3 the center of gravity of which is slightly above the center of the shaft, as viewedl in Fig. 1. Bolt or plunger 3 is normally restrained from movement by a spring 4 which engages at one end a flange 5 on bolt 3 and at the other end a nut 6, which is adjustable on a sleeve 7 to vary the setting of the spring. Mounted adjacent the shaft in the r plane of bolt 3 is a trip finger 8 which is vpivoted at 9 and normally supports a rod 10, upon which a spring 11 presses. l/Vhen the trip finger is turned in a clockwise direction, rod 10 is released and forced downward by spring 11. The movement of rod 10 eects the closing of the emergency valve. At 12 is indicated the resetting rod for trip finger 8. As viewed'in the drawing, the shaft rotates in an anticlockwise direction.

The construction so far described is that Application filed. October 20, 1924. Serial No. 744,700. v

of aknown type of emergency trip governing mechanism, the operation of which is well understood. Y The bolt?)V is thrown out by centrifugal force againstthe action of spring AI in vcase of excess speed, striking trip finger'8 and turning itfon its pivot 9 to release rod 10 and effect actuation of the emergency valve mechanism. In operating the bolt goes froin'its-iniier position to its outer position in a fraction'of a revolution,

as is well understood.

Myinvention relates especially to, theconstruction of tripfinger8.h I

According to my invention I provide the trip linger 'with a striking face or actuating surface indicated at 13 which is concave and has a curvature such as to give substantially harmonic motion to the trip linger for equal angular motion of the head of bolt or plunger 3. In laying out the curvature kof the striking face 13, I may proceed as follows (see Fig. 2) Vith the point 14 as the center of rotation of the governor and with a radius proportional to the striking radius, I lay off an arc 15. Then with the same center and a radius proportional to the tripping radius plus a small amountto take care of variations in manufacture, I lay olf a second arc 16. In this connection it is to be understood that by the striking radins I meanthe distance from the center of rotation of the governor to the nearest point of the striking face of the trip iinger which point is indicated at 17 in the drawing, and by the tripping radius I mean the distance from the center of rotation to the end of the plunger rod after it has been thrown outward to tripping position. The radial distance between arcs 15 and 16 represents the actual distance the trip finger is moved by the plunger. 'I he length which the striking face is to have, that is the strikingdistance, has been selected and this distance Yon arcs v15 and 16 is divided into equal arcs by radial lines 18. Now with a point 19 on the arc 15 as a` center and with a radius equal to the radial distance between arcs 15 and 16, an arc 20 is drawn from line 15 to line 16, and this arcis divided into a number of equal parts corresponding to the number of lines 18. Arcs from the center of rotation 14 of the governor are now drawn through the equidistant points on arc 2O to the correspending radiating lines 18, thereby locating points a, 2'), c, (l, e, etc. which are points on the striking face of the trip linger. A line through these points then gives the contour for the striking face 13. l a

I have found in actual practice that by the use of a trip finger embody-ing my invention, difiiculty due to the breaking of trip fingers is overcome. This is due to the fact that the improved trip finger when struck by the head of the bolt or plunger is set into motion and accelerated gradually and hence is not subjected to'shoclzs `as great as is other- Wise the case. Also my improved construction enables the trip finger to be made lighter in Weight than heretofore and still `possess the strength necessary to withstand the blovvs of the bolt or plunger. This is of advantage in that it means that the inertia of the trip finger is less and that hence it is more easily :`.J V set into motion.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with thelapparatus which I noiv` consider to represent the best embodiment thereof, but I desire to have it understood `that the apparatus shown is only illustrative and that the invention may be carried out by other means. f j

What I claim as nevv and desire to secure by Letters Patentof the Unitedl States,l is z- In an emergency governor, the combination of a rotating striking member, and a trip finger having a striking surface adapted to beengaged by the rotating member, said striking surface being concave and having a y curvature such that the initial movement of the trip linger is comparatively sinallfand successive equal angular movements `of the striking member produce gradually increasing outward movements of the trip finger.` i

In Witness whereof, I have hereunto set my hand this 17th day of October, 1924.

.Y FRANK C. LINNL"

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