US2385213A - Speed responsive device - Google Patents

Description

Sept. 18, 1945.

J. W. LIVINGSTON SPEED RESPONS IVE DEVICE Original Filed Dec. 11, 1941 &

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o R I v\ I HIS JI'IORNEY Patented Sept. 18, 1945 SPEED RESPONSIVE DEVICE John Livingston, Lynbrook, N. Y., assignor to The Union Switch and Signal Company, Swissvale, Pa., -a corporation of Pennsylvania Original application December 11, 1941, Serial No. 422,467, now Patent No. 2,338,859, dated Janu-' ary 11, 1944. Divided and this application September 23, 1943, Serial No.503,513

2 Claims.

My invention relates to speed responsive devices, and particularly to governors which are adapted for use on trains in connection with automatlc train control equipment to limit the speed at which the trains may operate under certain conditions.

One object of my invention is the provision of a governor which has a high degree of sensitivity at predetermined critical speedsboth accelerating and decelerating.

Another object of my invention is the provision of a governor in which the force resulting from the centrifugal force of the centrifuge members and the centripedal force of the springs is used only to move cam means between two contact operating positions, and in which the force necessary to operate the governor contacts by the cam means is never in a direction to oppose the motion of the centrifuge members resulting from the difference between the centrifugal and centripetal forces.

Governors embodying my invention are an improvement upon the governor shown and described in an application for Letters Patent of the United States, Serial No. 412,665, filed on September 27, 1941, by Herbert L. Bone for Speed responsive devices, now Patent No. 2,308,265 issued January 12, 1943.

The present application is a division of my pending application, Serial No. 422,467, filed on December 11, 1941 for Speed responsive devices, now Patent No. 2,338,859 issued January 11, 1944.

According to my invention, the motion of weighted centrifuge members which are biased by spring means to one position and are movable to another position in response to centrifugal force is utilized to operate cam means between two contact operating positions. The cam means when moved from either contact operating position to the other engage contact operating members to thereby actuate contacts, the parts being so arranged that the forces exerted by the cam means in actuating the contact operating mem- :bers are applied substantially at right angles to the plane in which the centrifuge members oscillate, and that none of the force components which are developed are in a direction to oppose the motion of the centrifuge members resulting from the difference which then exists between the centrifugal and centripetal forces.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe one form of speed responsive device embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Figs. 1 and 2 are vertical sectional and front views, respec tively, showing one form of speed responsive apparatus embodying my invention, some of the parts :being shown diagrammatically in the interest of simplicity. Fig. 3 is a detail view of a portion of the apparatus illustrated in Figs. 1 and 2 taken on the line III-III of Fig. 1.

Similar reference characters refer to similar parts in all three views.

Referring to the drawing, the governor here shown comprises two centrifuge members Al and BI pivotally attached by means of pivot pins 22 and 23 to a rotary member I in such manner that the centrifugemembers are free to oscillate in a plane which extends parallel to the plane of the rotary member I. The centrifuge members each comprise a main arm 6 provided at its free end with a weight I, and an auxiliary arm 8 which extends substantially at right angles to the main arm 6. The auxiliary arms 8 serve to connect the two centrifuge members together to cause them to operate in unison, and to this end, the free end of the arm 8 of'the centrifuge member Al is provided with bifurcations 8a which straddle a tongue 8b provided on the free end of the arm 8 of the centrifuge member Bl. The centrifuge members are free to swing between inner and outer positions, as will appear presently, and are biased to their inner positions by means of coil springs l0 secured at their opposite "ends to the main arms 6 by means of pins ll.

The rotary member I is mounted on a drive shaft 12 which is adapted to be rotated at a speed which is proportional to the speed of a train or any other device to whose speed it is desired to have the governor respond.

The weights 1 are recessed for the reception of two cam rods 24 and 25. These cam rods are held inplace'in the recesses by means of pins 26 and 21 carried by the weights 1. As best seen in Fig. 1, the pin 26 extends through a clearance hole 24a in the cam rod 24 and an elongated slot 25a in the cam rod 25, while the pin 21 extends through an elongated slot 24b in the cam rod 24 and a clearance hole 25b in the cam rod 25. The slots 24b and 25a have a length equal to the distance through which the pins 26 and 21 move in response to the movement ofthe centrifuge members between their inner and outer positions, and serve as stops to limit the motion of the centrifuge members. These slots also serve to permit the cam rods to move in opposite directions in response to the movement of the centrifuge members between their inner and outer positions. The rod 24 is made somewhat longer than the rod 25, and the parts are so proportioned that when the centrifuge members occupy their inner positions, the end 240 of the rod 24 will project beyond the ends 250 of the rod 25 but that, when the centrifuge members are swung to their outer positions, the end 250 of the rod 25 will then project beyond the end 240 of the rod 24 the same amount that the end 240 projects beyond the end 250 under the conditions first mentioned. I

The ends 240 and 250 of the rods 24 and 25 are oval shaped, and cooperate with opposed cam surfaces 28a and 28b formed on a rocker 28 secured to one end of a rocker shaft H. The rocker 28 is free to oscillate between two extreme positions, and is biased to its nearest extreme position, whereby when the rocker is moved from either extreme position to the other it will move with a snap action and will subsequently be held in whichever extreme position it is moved to until it is positively movedaway from this position. As best seen in Fig. 3, the cam surfaces 28a and 28b converge toward the center from either end of the rocker but are spaced apart at their closest point a distance which is slightly greater than the width of the ends 240 and 250 of the cam rods 24 and 25. The parts are so proportioned that the cam surface 28a will project into the path of movement of the end 240 of the rod 24 when and only when the cam rod 24 is moved to its outer position, and the rocker is rotated to its one extreme position, and that, the cam surface 281) will project into the path of movement of the end 250 of the cam rod 25 when and only when the cam rod 25 is moved to its outer extreme position and the rocker 28 is rotated to its other extreme position. The parts are further so proportioned that when either cam surface projects into the path of movement of one of the cam rods, the engagement of the cam rod with such cam surface in response to rotation of the rotary member I will move the rocker from the extreme position it then occupies to its opposite extreme position whereupon the cam rod which caused the movement of the rocker will be free to swing between the cam surfaces without touching either surface as. long as the rod remains in its projected position.

The movement of the rocker shaft H between two extreme positions resulting from movement of the rocker between its two extreme positions may be utilized to control suitable contact mechanism here shown diagrammatically as comprising a movable contact finger 21 which engages a fixed contact member Zia or a fixed contact member 21b to close a contact 2i--2 la or 2 l-2lb according as the rocker i6 is rotated to its one or its other extreme position. I

It should be noted that since the movement of the rocker 28 between its two extreme positions is effected by engagement of the rocker with the sides of the push rods 24 and 25, the reaction forces which are set up when the rocker is reversed will be disposed substantially at right angles to the plane of the pivots 22 and 23, and will not therefore at any time oppose the force which is effective to move the centrifuge mem- -bers to either their inner or their outer positions.

One advantage of a governor constructed in accordance with my invention is that since the only force which it is necessary for the centri fuge members to exert is the force necessary to move the cam arms or cam rods between their two contact operating positions the governor is more sensitive than governors constructed in the customary manner, and is not subject to the unsatisfactory contact operation characteristics of previous designs of governors.

Although I have herein shown and described only one form of speed responsive device embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A governor comprising a rotary member which is adapted to be rotated at different speeds, a pair of centrifuge members pivotally attached to said rotary member at diametrically opposite points for movement between inner and outer positions, said members being connected together to operate in unison and being biased to their inner positions by spring means, a rocker pivotally mounted adjacent said rotary member and provided with opposed cam faces which converge from their outer ends toward the center, and two cam rods secured to said centrifuge members in such manner that one rod or the other will be moved to a position in which it will move between said cam faces in response to rotation of said rotary member according as said centrifuge members are moved to their inner or their outer positions, the parts being so proportioned that said rocker will be rotated to one position by engagement of the one cam surface with the side of said one rod in response to rotation of said rotary member when said centrifuge members occupy their inner positions and to another position by engagement of the other cam surface with the side of said other rod in response to rotation of said rotary member when said centrifuge members occupy their outer positions.

2. A governor comprising a rotary member which is adapted to be rotated at different speeds, a pair of centrifuge members pivotally mounted on said rotary member at diametrically opposite points, said centrifuge members being connected together to operate in unison and each being provided with a weight arm having a weight formed with a recess, two cam rods disposed in said recesses and secured to said weights by pins in such manner that when the centrifuge members occupy their inner positions the one end of the one rod will project outwardly beyond the corresponding end of the other rod but that when the centrifuge members occupy their outer positions the one end of the other rod will pro- J'ect outwardly beyond the corresponding end of the one rod, a pivoted rocker provided with opposed cam faces which converge toward the center and which are spaced apart a distance slightly greater than the widths of said rods at their projecting ends, said rocker being so positioned that when said rotary member is rotated said rocker will be rotated to one position or the other by engagement of the projecting end of the one rod or the other with the one cam face or the other.- 7

JOHN W. LIVINGSTON.

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