US2027848A - Emergency tripping device - Google Patents

Description

Jan. 14, 1936.. D. F. WARNER EMERGENCY TRIPP ING DEVICE Filed Oct. 2, 1935 lr'wverwtorz Donald F Warmer,

His Attorrlg Patented Jan. 14, 1936 UNKTED STATES E A'EENT @FEEQE EMERGENCY TRIPPING DEVECE York Application October 2, 1935, Serial No. 43,227

6 Claims.

The present invention relates to emergency tripping devices or emergency speed governors, such as are used, for instance, in connection with elastic fluid turbines to effect shutting or controlling of an inlet valve for elastic fluid as the speed of the turbine rises beyond a predetermined fixed value.

The object of my invention is to provide an improved construction and arrangement of oemergency tripping devices which is simple in design, reliable in operation, and can be manufactured at comparatively low cost.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. l is a somewhat diagrammatic view, partly in section, of an emergency speed tripping device or governor, in accordance with my invention, and Fig. 2 shows certain elements of the device in a different position.

The device includes a casing having a lower half I and an upper half II with a cover l2, suitably fastened to the upper half l l. A governor shaft l3 projects into the casing. The shaft may be secured to or form'a part of a shaft of a turbine or like prime mover to be controlled. A fiyweight in the form of a plunger M with a disc I5 at its lower end is disposed in a radial bore or recess [6 in the shaft l3 and held therein by means of a screw plug H.

The flyweight I4 is biased inwardly; that is, towards the center of the shaft, by means of compression spring l8 surrounding the plunger M and bearing against the disc l5 and the plug H. The arrangement so far described is typical of any emergency speed tripping device.

During normal operation, the fiyweight or plunger I4 is biased inwardly against the centrifugal force acting thereon. As the speed of the shaft l3 rises beyond a predetermined value, said centrifugal force overcomes the biasing force of the compression spring l8 and thereby permits radial outward movement of the plunger It. The end of the plunger It, as clearly indicated, projects through an opening H) in the plug ll. The shaft l3 and the plunger l4 represent in substance a speed responsive mechanism.

Means are provided in co -operative relation with the plunger M and moved thereby as the plunger is forced outward to effect tripping of certain elements which in turn cause adjusting of an element to be controlled. The means cooperating with the plunger I4 comprise, in accordance with my invention, a combined trigger and tripping post is which in the present instance has the form of a bar. Thus, a trigger and tripping element are united to form a single element 20. In analyzing this element, it is noted that the lower part thereof acts as a trigger element and the upper part thereof acts as a trippingpost or element. From another viewpoint, the trigger of my emergency tripping device is formed as an integral projection of the tripping post. The combined trigger and tripping post projects through an opening 2! in the cover 12 and a cylinder 22 integrally united with the cover H. The lower portion of the combined trigger and tripping post, the trigger, is arranged in co-operative relation with the flyweight M. The upper end of the combined trigger and tripping post is connected by a pivot 23 to an arm of a bell crank lever, which latter is held on a fulcrum 24 secured to the cover l2. The other arm of the bell crank lever is pivotally connected to a link 25 which may be connected to an element to be controlled, such as in the example mentioned above, to an inlet valve of an elastic fluid turbine. The combined trigger and tripping post or bar forms ashoulder 26, which in operative position as shown in Fig. 1, rests on a stop, or like element, which in the present intance is formed by a plate 21 secured to the lower end of the cylinder 22 by means of bolts 28. If the combined trigger and tripping post is moved towards the right; that is, out of engagement with the plate 2?, it is forced downward by the action of a compression spring 29 surrounding the combined trigger and tripping post and disposed within the cylinder 22. The upper end of the spring bears against the plate l2 and the lower end bears against a cross-pin 38 secured to the combined trigger and tripping post and having ends disposed in slots 3! and 32 respectively of the cylinder 22. as will be clearly noted in the drawing the right-hand end of the pin 35 is heavier than the left-hand end. This is an important feature of my invention in that it causes the compression spring 29 to become compressed more on its right-hand side than on its left-hand side. This difierence in compression between the two sides of the spring 29 effects a twist, or turning action, of the combined trigger and tripping post in clockwise direction so that the lower end of said combined trigger and tripping post is forced towards the left and thereby assures engagement between the shoulder 26 and the plate or stop 21. From another viewpoint, the compression spring 29 serves two purposes, first, to effect downward movement of the tripping post during emergency conditions, and second, to maintain the trigger and tripping post in operative position. Hence, the compression spring 29 represents in substance a combined trigger and tripping post spring and the crosspin 3B broadly constitutes a means for maintaining compression of the spring 29 and for compressing one side of the spring more than the other.

During operation, that is during rotation of the shaft i3, the device remains in the operative position shown in Fig. 1 until the speed of the shaft l3 rises beyond a predetermined value. If this occurs, the fiyweight I4 moves radially outward into engagement with the lower end of the combined trigger and tripping post and thereby forces this lower end towards the right. This causes disengagement between the shoulder 26 and the stop or plate 21, permitting the compression spring 29 to force the combined trigger and tripping post downward, resulting in counterclockwise turning movement of the bell crank lever and movements towards the left of the link 25. In case this link is connected to an elastic fluid turbine inlet valve, the arrangement is such that said valve is shut. Downward movement of the combined trigger and tripping post and disengagement between the shoulders 26 and the stop or plate 21 is facilitated by the provision of an inclined surface 33 adjacent the shoulder 26. From another viewpoint, the inclined surface 33 indicates a portion cut away from the lower part of the tripping post so that slight movement of the fiyweight effects tripping of the device. Fig. 2 shows the arrangement when tripped. Resetting is accomplished manually by forcing the combined trigger and tripping post upward against the force of the spring 29 until the shoulder 26 engages the plate 21. The compression spring 29, together with the fiyweight i4, represents means for effecting an automatic tripping in response to certain speed or like emergency conditions.

Tripping may also be effected manually. To this end, a cam 34 is provided within the lower casing half iii in co-operative relation with the lower end of the combined trigger and tripping post. The cam 34 may be turned by means of a handle 35 disposed outside the casing. Turning of the cam forces the lower end of the combined trigger and tripping post towards the right, whereby the shoulder 26 is moved from its engagement with the plate 21, thus permitting downward movement of the combined trigger and tripping post by the action of the compression spring 29 as heretofore described.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An emergency tripping device including the combination of a speed responsive element, a'

combined trigger and tripping post in co -operative relation with said element, and a combined trigger and tripping post spring for maintaining the trigger and tripping post in co-operative relation with said element and for effecting movement of the combined trigger and tripping post in response to movement of said element.

2. An emergency tripping device including the combination of a casing, a rotable shaft projecting into the casing, a fiyweight on the rotatable shaft, a combined trigger and tripping post in co-operative relation with the fiyweight and having a shoulder, a stop normally engaging the shoulder, and a combined trigger and tripping post spring for maintaining the combined trigger and tripping post in co-operative relation and for moving the combined trigger and tripping post in response to movement of the fiyweight.

3. An emergency tripping device including the combination of a bar, an element to be controlled connected to the bar, a stop for normally holding the bar in a certain position, a mechanism for disengaging the bar from the stop in response to an emergency condition, and a single spring for normally maintaining engagement between the bar and the stop and for effecting tripping of the bar after the bar has been disengaged from the stop.

4. An emergency tripping device including the combination of a bar, an element to be actuated by the device connected to the bar, a stop for normally holding the bar in a fixed position, means for efiecting disengagement between the bar and the stop in response to an emergency condition, a spring for tripping the bar after disengagement between the bar and the stop, and means including the aforementioned spring for normally maintaining engagement between the bar and the stop.

5. An emergency tripping device including the combination of a shaft having a radial opening, a plunger held in and projecting through the opening, means including a spring surrounding the plunger to bias it radially inward against the action of centrifugal force, a combined triggel and tripping post in the form of a bar having a portion in co-operative relation with the plunger, a casing for the combined trigger and tripping post, a stop secured to the casing engaging the combined trigger and tripping post to normally hold it in a fixed position, the combined trigger and tripping post being disengaged from the stop in response to a certain movement of said plunger, and means for effecting tripping of the disengaged combined trigger and tripping post, said last-named means comprising a cross-pin secured to the combined trigger and tripping post and a compression spring between the cross-pin and the casing.

6. An emergency tripping device including the combination of a casing forming a stop, a bar forming a combined trigger and tripping post, astop on the casing engaging the bar to normally hold the bar in a certain position, means including a shaft and a flyweight held on the shaft for disengaging the bar from the stop in response to an emergency condition, and means for normally maintaining. engagement between the stop and the bar and for effecting tripping of the bar after the bar has been disengaged from the stop, said last-named means consisting of a spring surrounding the bar and means for effecting different compressions of the two sides of the spring.

DONALD F. WARNER.

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