Title:
Governor
United States Patent 2402285


Abstract:
The invention relates to governors especially for elevators. In elevator operation, the elevator car and in some instances the counterweight is provided with a safety brake carried thereby for engaging the guide rails to stop the body under emergency conditions. The operation of these safety...



Inventors:
Frederick, Hymans
Application Number:
US48106143A
Publication Date:
06/18/1946
Filing Date:
03/29/1943
Assignee:
OTIS ELEVATOR CO
Primary Class:
Other Classes:
73/546, 73/548, 187/305
International Classes:
G05D13/00
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Description:

The invention relates to governors especially for elevators.

In elevator operation, the elevator car and in some instances the counterweight is provided with a safety brake carried thereby for engaging the guide rails to stop the body under emergency conditions. The operation of these safety brakes is controlled by speed governors. For example, in the case of a safety brake carried by an elevator car, roping is attached to the car and passes around a governor pulley at the top of the hatchway to drive the governor. In case the car should overspeed downwardly, as in the case of a falling car, the governor acts to grip the governor rope and thus cause the application of the safety brake to stop the car. It is desirable, especially in the case of the slow speed, low cost installations, that the cost of manufacture and installation of the governor be kept at a minimum. A governor which is especially suitable for such installations is one in which the governor weights are pivotally mounted on the governor sheave to be swung about their pivots by the action of centrifugal force. The invention is especially directed to governors of this character. One object of the invention is to provide a governor which is of simple construction, economical to manufacture and install and quite in operation.

Another object of the invention is to provide a governor in which unwanted operation due to inertia of the governor weights is obviated.

The invention in one aspect involves connecting the governor weights so that lost motion is obviated. In another aspect, the invention involves biasing the governor weights against the action of centrifugal force by a spring common to the weights. In still another aspect, the invention involves the utilization of weights, the relationship of the center of gravity of each of which to its pivot is such as to prevent actuation of the governor to grip the rope due to the inertia of the weights.

The invention and various features and advantages thereof are set forth in the following description, taken in conjunction with the accompanying drawings, and appended claims.

In the drawings: Figure 1 is a schematic view of an elevator installation with a governor embodying the invention; Figure 2 is a front view with parts broken away of the governor illustrated in Figure 1; and Figure 3 is a view taken along the line 3-3 of Figure . 25 Referring to Figure 1, hoisting ropes 10 for the elevator car 1 and counterweight (not shown) pass over the hoisting sheave 12 at the top of the elevator shaft. This sheave is driven by means of a hoisting motor 13 to effect the raising and lowering of the car and counterweight. An electromechanical brake 14 is employed to aid in bringing the motor to a stop and to hold the car while at rest. Guide rails 15 are provided for the elevator car. The bottom guide shoes for the car are designated 16, while the top guide shoes are designated 17. These guide shoes cooperate with the guide rails to guide the car in its movement up and down the elevator shaft.

The governor rope 21 extends around the governor sheave 22 at the top and a tensioning sheave 23 at the bottom of the elevator shaft, the tensioning sheave being provided with tensioning weights 24. The governor rope is connected to one arm 25 of a bell crank lever 26 pivotally mounted on the upper cross channels 27 of the car frame. The other arm 29 of this lever is connected by a rod 28 to a similar bell crank lever 30 pivotally mounted on the cross channels at the other side of the car. The levers are latched in the positions illustrated by means of a link 31 pivoted to arm 29 of lever 26 and yieldably held between a fixed pin and a movable pin by a spring 32, to provide a releasing carrier. These levers are adapted, upon upward movement of arm 25 by the governor rope to swing lever 26 clockwise, to operate lift rods 33 to cause the safety brake 34 to grip to the guide rails.

Referring now to Figures 2 and 3, the governor sheave 22 is keyed to a shaft 35 rotatably mounted in bearings 48 in pedestals 36 extending upwardly from base 37. Pivotally mounted on sheave 22 on pins 38, 39 and 40 secured to the sheave, are weights 41, 42 and 43. The weights 41, 42 and 43 are connected by leaf springs 44, and 46 respectively to a ring 47 concentric with shaft 35. The leaf springs are secured to their weights as by screws 50. Each of leaf springs 44 and 45 is secured to the ring as by a screw 51 *extending through washer 52. The remaining leaf spring 46 is secured to the ring by a screw 51 extending through a flange 53 of a bracket 54 and washer 55. In this way the leaf springs are solidly connected to the weights and ring, thereby obviating any lost motion with attendant noise in operation. The washers 52 and 55 and flange 53 are slightly beveled toward the weights to allow for flexing of the springs. A plurality of rollers 56 are rotatably mounted on. the ring at radially spaced intervals for rolling on the hub 57 of sheave 22. The weights are biased to the position illustrated by a spring 58. This spring is a helical spring positioned about a rod 60 extending through an aperture in a stop 61 preferably adjustable in a slot 59 in sheave 22. The other end of the rod is connected by a pin extending through a clevis head formed on the rod and the bracket 54. The spring is in a state of compression and extends between stop 61 and a shoulder 62 formed on the clevis end of the rod.

Each of the weights is formed with a dog 63 for engaging one of a plurality of lugs 64 formed on the inside of the rim 65 of a shell 66 rotatably mounted on shaft 35. Shell 66 is coupled to a yoke 67. This yoke comprises a pair of arms 68 secured as by pins at their lower ends to stub shafts 70 pivotally mounted on pedestals 36. An adjustable stop 71 formed on one of the pedestals 36 limits the counterclockwise movement, as viewed in Figure 2, of the yoke about the pivot formed by the stub shafts. The coupling of the yoke to the shell is effected by means of a weblike projection 72 extending into the slot 73 between two lugs 74 and 75 formed on the rim of the shell. The yoke carries a rope grip 76 for gripping the governor rope 21 when the yoke is swung clockwise about its pivot. The rope grip is a wedge-shaped head of a bolt 77 mounted in apertures in cross portion 78 and the end 80 of the yoke. The head of the bolt is held out of engagement with the rope when the yoke is in its normal position against the stop. This is effected by a nut 81 on the threaded end of the bolt and engaging the end 80 of the yoke, by means of which the distance of the grip from the rope may be adjusted. Arranged on the bolt between the cross portion 78 and the end 80 of the yoke is a helical spring 82 under an initial compression. Between the inner end of the spring and the cross portion is a washer 83 abutting against the shoulder 84 on the bolt. Another washer 85 is arranged underneath the end 80 of the yoke and adjusting washers 86 are provided between washer 85 and the spring for adjusting the compression of the spring.

In operation, as the car starts to move, the governor sheave is driven by the governor rope, the governor weights 41, 42 and 43 and ring 47 rotating as a unit along with the sheave. Due to the centrifugal force exerted by the weights, they are swung outwardly about their pivot pins.

This pulls ring 47 counterclockwise relative to the hub 57 of sheave 22 as viewed in Figure 2, rollers 56 rolling on the hub as this movement takes place. The relative movement of the ring is effected against the force of spring 58, rod 60 moving outwardly in the aperture in stop 61 as the spring is compressed. So long as the car does not exceed a certain speed, the shell 66 re- g0 mains stationary and yoke 67 remains in the position illustrated against its stop 71. However, should the car in its downward movement exceed this certain speed, the governor acts to cause the gripping of the governor rope. When the car 66 is moving downwardly the weights are being rotated clockwise as viewed in Figure 2. When this certain speed is exceeded a dog 63 on one of the weights engages one of the lugs 64 on the rim 65 of the shell. This causes clockwise rotative movement of the shell and, due to the coupling of the shell with the yoke, clockwise movement of the yoke about its pivot pins into position for the rope grip to engage the governor rope. This retards movement of the rope thereby lifting arm 25 of lever 26 and pushing link 31 out of the position in which it is held by spring 32, lever 26 acting through rod 28 to swing lever 30 counterclockwise. This movement lifts the rods 33 to cause application of the safety brake to stop the car. The spring 82 yields as the rope grip is applied to the rope to permit the rope to be pulled through the grip as much as is necessary in effecting the stopping of the car. In resetting the governor after the condition causing the overspeed is corrected, the spring 58 restores the weights and the ring to the position illustrated, a stop plate 90 being secured to weight 41 adjacent bracket 54 to be engaged by the bracket and thus limit the clockwise rotative movement of the ring.

The connection of the weights by the leaf springs 44, 45 and 46 to the ring 47 obviates any loose joints in the connections of the weights either initially or due to wear and thereby assures quiet operation at these points throughout the life of the governor. The single spring 58 assures an equal biasing force for each weight.

Each of the weights is formed with its center of gravity at such point that a line extending through the pivot point of the weight and its center of gravity is substantially tangent to a line extending radially from the center of the sheave 22 through the center of gravity of the weight. This construction obviates any unwanted operation of the governor due to the inertia of the weights under conditions of sudden rapid acceleration.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: 1. A governor in which a driven sheave has a plurality of weights pivotally mounted thereon to be swung about the pivots by the action of centrifugal force upon rotation of the sheave, in which a member is provided which is rotatable about the axis of said sheave and in which a plurality of connecting members is provided, one for each weight, for connecting the respective weights to said rotatable member, characterized in that said connecting members are flat springs, each spring being solidly connected at one end to its weight and being solidly connected at its other end to said rotatable member and that a spring acting through said rotatable member is provided to bias said weights against the action of centrifugal force.

2. A governor in which a driven sheave has a plurality of weights pivotally mounted thereon to be swung about the pivots by the action of centrifugal force upon rotation of the sheave and in which means is actuatable by said weights upon their being moved a certain amount about their pivots, characterized in that the relationship of the center of gravity of each weight to its pivot point is such as to prevent the actuation of said actuable means by said weights due to their inertia.

3. A governor in which a driven sheave has a plurality of weights pivotally mounted thereon to be swung about the pivots by the action of centrifugal force upon rotation of the sheave, in which a member is provided which is rotatable relative to said sheave about the axis thereof and in which a plurality of connecting members is provided, one for each weight, for connecting the respective weights to said rotatable member, characterized in that the relation of the center of gravity of each weight to its pivot point is such that a line passing through the center of gravity and pivot point is substantially tangent to a circle concentric with said sheave and passing through the center of gravity and that said connecting members are flexible members, each flexible member being solidly connected at one end to the weight for which it is provided and being solidly connected at the other end to said rotatable member to translate the pivotal movement of said weights into rotative movement of said rotatable member without lost motion, and that resilient means connected to said rotatable member is provided for biasing said weights against the action of centrifugal force.

4. A governor in which a driven sheave has a plurality of weights pivotally mounted thereon to be swung about the pivots by the action of centrifugal force upon rotation of the sheave, in which means is actuatable by said weights upon their being moved a certain amount about their pivots, in which a member is provided which is rotative relative to said sheave about the axis thereof and in which a plurality of connecting members, one for each weight, is provided for connecting the respective weights to said rotatable member at equally spaced points on said rotatable member for translating the pivotal movement of said weights into rotative movement of said rotatable member, characterized in that said connecting members are flat leaf springs, said springs being solidly secured to said weights and rotatable member, that a compression spring acting through said rotatable member is provided to bias said weights against the action of centrifugal force, and that the relation of the center of gravity of each weight to its pivot point is such that a line passing through the center of gravity and pivot point is substantially tangent to a circle concentric with said sheave and passing through the center of gravity to prevent the weights being swung about their pivots by inertia into position to actuate said actuatable means upon a sudden start of said sheave.

FREDERICK HYMANS.