US1936578A

US1936578A - Speed controlling and speed measuring centrifugal mechanism

Info

Publication number: US1936578A
Application number: US642812A
Authority: US
Inventors: Theodore H Barth
Original assignee: CARL L NORDEN Inc
Current assignee: CARL L NORDEN Inc
Priority date: 1931-07-15
Filing date: 1932-11-15
Publication date: 1933-11-28
Anticipated expiration: 1950-11-28

Description

Nov. 28, 1933. H, EARTH 1,936,578

SPEED CONTROLLING AND SPEED MEASURING CENTR-IFUGAL MECHANISH Original Filed July 15, 1931 2 Sheets-Sheet l 5 L. h 6 INVENTOR. T E 5%20 owe/'36 am/0C6,

d ATTORNEY No 28, 1933. T E TH 1,936,578

SPEED CONTROLLING AND SPEED MEASURING CENTRIFUGAL MECHANISM vOriginal Filed July 15, 1931 2 Sheets-Sheet 2 Iii-E I; -&

5 6 45 2 +1 E g 45 8 3.9 if, 9 g; 02

40 E 1 a 44 92a 42 42 37 42 Z? 42 1 6 I: is. 5 ATTORNELQ Patented Nov; 28, 1933 UNITED STATES SPEED CONTROLLING AND SPEED MEASUR- ING CENTRIFUGAL MECHANISM Theodore H. Barth, New York, N. Y., assignor to Carl L. Norden, Inc., New York, N. Y., a corporation of New York Original application July 15, 1931, Serial No.

551,008. Divided and this application November 15, 1932. Serial No. 642,812

9 Claims.

My invention relates broadly to speed controlling and speed measuring centrifugal mechanism, and more particularly to an improved construction of speed controlling mechanism having a high degree of precision in its operation.

This application is a division of my application Serial No. 551,008, filed July 15, 1931, for Speed controlling and speed measuring centrifugal mechanism.

One of the objects of my invention is to provide a construction of control mechanism having a high degree of precision for maintaining rotary motion at constant speed.

Another object of my invention is to provide an improved construction of governor mechanism for rotary systems which insures constant speed operation of rotary mechanism without employing bulky or complicated parts.

Still another object of my invention is to provide a simplified construction of centrifugal governing mechanism in which a control member is shifted under conditions. in which variations in speed of rotation tends to occur for maintainmg cooperatively related rotating mechanism at constant speed.

A further object of my invention is to provide a centrifugal mechanism for governing the operation of rotary elements wherein a contactor may be accurately balanced for operation by the centrifugal mechanism under predetermined conditions.

A still further object of my invention is to provide an arrangement of balance weights coordinated with a contactor which is controlled by i a centrifugally operated mechanism with means for selectively controlling the effect of the balance weights upon the centrifugal mechanism for correspondingly controlling the operation of the contactor.

Another object of my invention is to provide a construction of statically balanced governor mechanism which may be employed on swiftly moving bodies such as aircraft for controlling rotary mechanism with all moving parts of the governor so balanced that no free couples nor any unbalanced force result from running at any speed except the control reaction balanced by the external force or forces.

Other and further objects of my invention reside in the construction of speed control mechanism described more fully in the specification hereinafter following and shown in the accompanying drawings, in which:

Figure 1 is a cross-sectional view taken through the speed controlling and speed measuring mechanism of my invention; Fig. 2 is a top plan view of the mechanism illustrated in Fig. 1; Fig. 3 is an end View of the mechanism illustrated in Fig. 1 looking in the direction of arrow A; Fig. 4 is a vertical cross-sectional view taken through the mechanism of Fig. 1 on line 44 thereof; Fig. 5 is an elevational view partially in cross-section taken through the adjusting means of the mechanism of my invention on line 5-5 of Fig. 2; Fig. 6 is a plan view of the rack member employed in the adjusting means of Fig. 5; Fig. '7 is a crosssectional view taken through the rack member on line 7-'7 of Fig. 8; and Fig. 8 is a cross-sectional view taken through the rack member on line 88 of Fig. 6.

My invention is directed to a speed control or measuring mechanism in which the working parts are statically balanced. The statically balanced arrangement of the working parts of the mechanism of my invention is highly important in that the mechanism is used chiefly upon moving bodies such as aircraft. The static balance of the parts of the mechanism of my invention may be defined as follows:

(1) All moving parts must be so balanced that no free couples nor any unbalanced force result from running at any speed, except the control reaction balanced by the external force or forces.

(2) The speed for which the governor is set must be constant regardless of the position of the governor in space, that is, regardless of any acceleration acting on the governor. Such accelerations include gravity and may include centrifugal and lateral accelerations, all acting in any direction relative to the driving axis.

The statically balanced system of levers employed in the system of my invention has the characteristic of exerting a movement proportional to the square of the linear displacement of one of the levers. t offers means to vary a constant moment according to a potential function of the second order, hence is imminently useful in connection Wi'ili controlling or measuring forces or couples due to centrifugal force.

The governor mechanism set forth herein has been found capable of controlling and measuring rotary speeds more closely and over a larger range than devices heretofore known. The system of my invention employs a centrifugal device for the precision control of rotary motors. The speed controlling or measuring mechanism of my invention permits the use of linear scales or linear functioning speed setting means and controlling or speed measuring can be done over the entire speed range accurately while the centrifugal elements revolve.

The mechanism of my invention includes a pair of pivotally connected weighted arms which are rotated under control of a driven shaft. A

tubular member on the frame of the governor extends in axial alignment with the driven shaft. A sleeve member is longitudinally adjustable along this tubular member under control of connecting links extending between the weighted arms and the sleeve member. A control rod or link extends through the tubular member and connects to a contact arm. The contact arm carries a contact member which is adapted to establish electrical connection with an aligned contact member. The contact arm is statically balanced about a fulcrum by balance weights associated with the contact arm. An extension is provided on the contact arm which is directly controlled through a floating and weighted system of levers. The effective points of aplication of the load through the floating levers is adjustable with a high degree of precision through a regulating knob with which there is associated a calibrated scale for selectively setting the speed at which the mechanism functions. The arrangement of weights and levers is such that the moving parts are balanced so that no free couples or any unbalanced force results from running at any speed except the control reaction balanced by the external force or forces. The speed for which the governor is set is constant regardless of the position of the governor in space, that is, regardless of any acceleration or deceleration to which the governor may be subjected. Such forces include gravity or longitudinal movement or external, centrifugal, or lateral movements, all acting in any direction relative to the driving axis. The mechanism of my invention is designed for precision operation for controlling the rotary motion of rotary mechanism independent of any external accelerations or decelerations to which the apparatus may be subjected by virtue of its location in a moving body of any description.

In the mechanism of my invention the contact arm is directly controlled by the system of weighted levers. Selected loading may be placed upon the contact arm to counterbalance predetermined centrifugal forces. The contact system which is made and broken by the movement of the contact arm is controlled at a rate dependent upon the centrifugal effort and the loading obtained by the adjustment of the control knob.

The leading characteristics of the system of my invention can be stated as follows. The only free and dynamically unbalanced forces of the revolving and active system are the centrifugal forces or couples to be measured or that are used for control purposes. The system is statically balanced for normal speed as well as for any definite control speed or speed to be measured. The sleeve loading, counteracting and balancing the centrifugal forces or couples of the rotating system is done entirely from the outside, and is variable from zero tothe maximum over the entire range while the centrifugal end is rotating. The weighing or governing is effected close to a definite position of the rotating centrifugal parts in respect to their axis of rotation. In case a sleeve in some form is used as part of the rotating system, it rotates in or on a non-rotating part, in order to obtain a maximum sensitivity. The external weighing or controlling devices can only be applied to centrifugal mechanism which permits the use of linear scales over the full range. The system can be used to control the speed of rotation of a conventional type of prime mover such as an electric motor. It can be used as a w itrolling device to limit the speed of rotation on an acting torque caused by means of a governing brake, or it can be used to control a variable speed gear to obtain closely a desired speed of rotation, and for many other similar purposes.

As applied to the construction of tachometers or other speed measuring or counting devices it eliminates many errors requiring correction in existing instruments; it extends the range of measuring, increases the accuracy and renders such accuracy more permanent. As applied to the construction of aerial sighting instruments of what is known as the synchronizing system, the system permits of setting in altitude in terms of speed of rotation, and if desired permits of synchronizing to a ground or drift speed by means of the linear speed control described hereafter, thus eliminating one or two variable speed gears and greatly simplifying the construction as well as increasing the obtainable accuracy. These applications in no way show the limits of the adaptability of the system and are but examples of such possible application.

The drawings illustrate the elements of my system in the simplest form, as applied to control the speed of an electric direct current motor, or servomotor. The centrifugal elements have, whether their speed of rotation is to be measured or whether they are to control to a definite speed a fixed zero position in which they are disposed when the motor is moving at its normal rate of speed. The total angular bar motion or axial sleeve motion is very small, hardly visible as such. Hence these governors can be either slightly static or astatic for this working position.

Referring to the drawings in more detail, reference character 1 designates the shaft of the rotary mechanism to be controlled. In this instance the mechanism is an electric motor which I have designated generally as having a commutator 50. A part of the motor frame is indicated at 2 carrying the radial and thrust bearing 3 in which the shaft 1 is rotatably mounted. Shaft 1 extends through a sleeve in the end of the housing 11 and terminates in a fork 5. Bars 4 are pivoted intermediate their ends upon a pin 6 carried by the fork 5. By this arrangement the bars 4 are maintained in crossed relation to each other. The center of gravity of the bars 4 is near the intersection of the axis of rotation and the tilting axis 6. The ends of bars 4, 4 are pivotally connected to links 7, '1, which can also be considered centrifugal elements connecting the cross bars 4, 4 to the sleeve 8. This sleeve rotates and slides on bushing 10, fixed to housing 11 which in turn is fixed centrally to motor frame 2. Sleeve 8 also forms the outer race of a ball thrust bearing for connecting rod 9, the end of which is enlarged and hardened and forms the inner race of the thrust bearing 9a which thus is self adjusting. The connection between cross bars 4, 4 and links '1, 7 is made by means of pins 12, 12 allowing angular movement between the cross bars and the links. The sleeve 8 is rotated by one of the links 7, the other having side clearance of its cross bar. Links 7 are pivotally connected with sleeve 8 through pins 13.

The connecting rod 9 is pivotally connected at 14a to control lever 14 which is pivotally mounted in fulcrum 01 in the bracket 3'1 which is fixed to the housing 11 about which the balanced weights 36 move. The lower end of the control lever 14 has an insulated extension 24 thereon. The insulated extension 24 carries contact member 25 which is aligned with the contact 27 carried by the support 26.v When the centrifugal force of the moving system constituted by arms 4 increases to a sufficient value for operating connecting rod 9 the control lever 14 is shifted for opening

contacts

25 and 27 against the resistance of the weighted system which will be described hereinafter. When the centrifugal force has dropped to a value in which the resistance offered by the centrifugal system is not suflicient to oppose the resistance offered by the weighted system,

contacts

25 and 27 are again closed. The lever 14 has a right angularly bent arm 1411 at its upper end providing a bearing surface upon which the single roller 38 carried by balanced lever 39 can move longitudinally. ,The complete lever 14, connecting rod 9 and sleeve 8, is accurately statically balanced with respect to the fulcrum 01 for which end weights 36 are provided.

Roller 38 is mounted in floating lever 39 which is pivoted on axis 02 with respect to which it is balanced. This lever is carried by fork 40 sliding in bracket 42 fixed to housing 11. The fork bar 40a has teeth 40b meshing with a setting pinion 4-3 fixed to knob 44, the pinion shaft 44a being journaled in bracket 42. Floating lever 39 is loaded by double roller 46 mounted in balanced lever 45, turning on axis 03 in bracket 3'7. The arrangement of floating

levers

39 and 45 is such that the lever 14 is normally maintained in balanced condition. The effect of the system of weights is selectively controlled by adjustment of control knob 44 which varies the distances between the fulcrum 02 and the point on lever arm 14b where the weight of lever 45 becomes effective through roller 38. Similarly the distance between fulcrum 02 and the point on lever 39 at which rollers 46 contact may be selectively varied. The lever arms are thus selectively changed as the knob 44 is adjusted. By this means the distance (11 between the fulcrum 01 and the axis of roller 38 may be selectively changed. The distance in between

rollers

38 and 46 is also selectively adjustable. Distance an between fulcrum 02 and the axis of roller 46 is selectively adjustable. The distance D: between fulcrum 01 and the axis of roller 46 remains constant. Distance bi=distance b2, lever distances a1 are equal to oz for all displacements of lever 39 and force 12, exerted causes a moment on lever 14 proportional to the square of the displacement of the floating lever from zero, for which or and az zero.

The speed of the governor is proportional to the square of the pulling force exerted on the connecting rod. Hence a linear motion of fork 40 will cause a linear speed change of the governor, for any moment set up by setting knob 22 whereas for a fixed position of the floating lever the governor speed will change with the square of the moment exerted by setting knob 22. The construction of the setting knob 22 is clearly described in the parent application Serial No. 551,008, filed July 15, 1931, and includes a spiral spring extending between one end of the shaft forming the fulcrum 03 and the knob 22. The headed screws 22a indicate the means for selectively fixing the tension of the spring within the knob when the desired tension has been placed upon the shaft constituting the fulcrum 03. The scale on setting knob 44 can therefore be linear and can be selected according to any desired calibration. Setting knob 22 can be set to obtain these speeds over the entire range of control knob 44. The arrangement permits the setting of one speed function by means of setting. knob 22 and then the varying of the governor speed as a linear function by lever displacement, completely replacing a variable speed gear for obtaining such linear variation, and also eliminating a primary variable speed gear which would be required if these functions were derived from a constant speed.

When the device is to be used as a tachometer, setting knob 22 can be simplified because the required adjustment of. force p is then limited so that an adjustable helical spring may be used. If such spring-adjustment is made for a middle range speed, so that for one mark, the speed reading on scale knob 44 is true, all other speeds will be true to their marks.

The control mechanism of my invention has been found highly practical in its construction and has a high degree of precision, and while I have described my invention in a certain preferred embodiment, I desire that it be understood that modifications may be made without departing from the spirit of my invention.

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

1. In a speed controlling and speed measuring apparatus, a rotatable shaft, a centrifugal governor connected with said shaft, a link member connected with said centrifugal governor and longitudinally shiftable in position according to the operation of said centrifugal governor, a lever member, said lever member being fulcrumed intermediate the ends thereof, a connection be tween said link member and one end of said lever member, a balancing lever adjacent the other end of said lever member, a roller carried by said balancing lever for establishing pressure contact with said lever member. an auxiliary balancing lever, a roller carried by said auxiliary balancing lever and establishing pressure contact with said first mentioned balancing lever, and means for variably tensioning said auxiliary lever for correspondingly controlling the pressure effect thereof on said first mentioned balancing lever for communicating a predetermined force to said lever member for resisting the force developed by said centrifugal governor and correspondingly controlling the operation of the lever members.

2. In a speed controlling and speed measuring apparatus, a rotatable shaft, a centrifugal governor connected with said shaft, a link member connected with said centrifugal governor and longitudinally shiftable in position according to the operation of said centrifugal governor, a lever member, said lever member being fulcrumed intermediate the ends thereof, a connection between said link member and one end of said lever member, a balancing lever adjacent the other end of said lever member, a roller carried by said balancing lever for establishing pressure contact with said lever member, an auxiliary balancing lever, a roller carried by said auxiliary balancing lever and establishing pressure contact with said first mentioned balancing lever, and means for variably shifting said first mentioned balancing lever for selectively fixing the point of pressure contact of the roller member thereon with said lever member for selectively determining the force opposing the force developed by said centrifugal mechanism for correspondingly controlling the operation of the lever member.

3. In a speed controlling and speed measuring apparatus, a rotatable shaft, a centrifugal governor connected with said shaft, a link member connected with said centrifugal governor and longitudinally shiftable in position according to the operation of said centrifugal governor, a lever member, said lever member being fulcrumed intermediate the ends thereof, a connection between said link member and one end of said lever member, a balancing lever adjacent the other end of said lever member, a roller carried by said balancing lever for establishing pressure contact with said lever member, an auxiliary balancing lever, a roller carried by said auxiliary balancing lever and establishing pressure contact with said first mentioned balancing lever, means for selectively moving said first mentioned balancing lever, a calibrated dial for determining the setting of said first mentioned balancing lever whereby the points of pressure contact between said first mentioned balancing lever and said lever member and between said auxiliary balancing member and said first mentioned balancing lever may be selectively adjusted for correspondingly controlling the force applied to said lever member for opposing the force developed by said centrifugal mechanism and correspondingly controlling the operation of the lever member.

4. In a speed controlling and speed measuring centrifugal mechanism, a rotatably driven shaft, a centrifugal governor connected with said shaft, a longitudinally movable link connected with said governor, a bell crank pivotally mounted adjacent said governor, a connection between said link and one end of said bell crank, a balancing lever extending parallel to the other end of said bell crank, a support for said balancing lever longitudinally shiftable with respect to said bell crank, calibrated mechanism for selectively setting said support, and means for establishing pressure contact between said balancing lever and said bell crank whereby selected opposing forces may be impressed upon said bell crank for resisting the forces developed by said centrifugal governor and correspondingly controlling the operation of the bell crank.

5. In a speed controlling and speed measuring centrifugal mechanism, a rotatably driven shaft, a centrifugal governor connecied with said shaft, a longitudinally movable link connected with said governor, a bell crank pivotally mounted adjacent said governor, a connection between said link and one end of said bell crank, a balancing lever extending parallel to the other end of said bell crank, a support for said balancing lever longitudinally shiftable with respect to said bell crank, calibra' ed mechanism for selectively setting said support, means for establishing pressure contact between said balancing lever and said bell crank whereby selected opposing forces may be impressed upon said bell crank, an auxiliary balancing lever extending in a plane substantially parallel to the first mentioned balancing lever, means for establishing pressure contact between said auxiliary balancing lever and said first mentioned balancing lever, and means for regula'ing the force imparted through said auxiliary balancing lever to said first mentioned balancing lever and to said bell crank for resisting the forces developed by said centrifugal governor and correspondingly controlling the operation of the bell crank.

6. In a speed controlling and speed measuring centrifugal mechanism, a rotatably driven shaft, a centrifugal governor connec'ed with said shaft, a link member connected with said governor, a bracket member supported adjacent said governor, a bell crank pivotally mounted in said bracket member, a connection between one end of said bell crank and said link member, a shiftable frame structure, a setting mechanism for selectively positioning said shiftable frame structure, a balancing lever pivotally mounted in said shiftable frame structure and extending in a plane substantially parallel to the plane of one portion of said bell crank,'means for imparting pressure contact from said balancing lever to said bell crank at a selected point along said bell crank as determined by the operation of said setting mechanism, an auxiliary balancing lever fulcrumed in said bracket above said first mentioned balancing lever and means for establishing pressure contact between said auxiliary balancing lever and said first mentioned balancing lever for communica ing a predetermined force to said bell crank for resisting the centrifugal effect of said governor and correspondingly controlling the bell crank.

7. In a speed controlling apparatus, a rotatable shaft, a centrifugal governor connected with said shaft, a link connected with said governor and longitudinally shif able according to operation,

of the governor, a bell crank lever fulcrumed intermediate its ends and having a horizontal arm and a depending arm, a connection between said link and the depending arm of said bell crank lever, a balancing lever extending longitudinally over the horizontal arm of the bell crank lever, said balancing lever being shiftable longitudinally and having a roller at its end resting upon the horizontal arm, an auxiliary balancing lever extending over the first mentioned balancing lever and having a roller at its end bearing against the first mentioned balancing lever between the roller and pivot point thereof, spring means acting upon the auxiliary lever and and exerting a bias thereon, and means for shifting the first mentioned balancing lever longitudinally.

8. In a speed controlling mechanism, a rotary shaft, weights connected with said shaft and displaceable under cenirifugal force in accordance with rotation of said shaft, a link displaceable longitudinally by said weights, a bell crank lever fulcrumed intermediate its ends, a connection between said link and one arm of said lever, and means for controlling movement of said bell crank lever including a balancing lever shiftable towards and away from the other arm of the bell crank lever and exiending longitudinally of the said arm with one end resting thereon, an auxiliary balancing lever pivoted to a stationary support and extending longitudinally over the first mentioned balancing lever with one end resting thereon approximately over the free end of the last mentioned arm of the bell crank lever, and spring means acting upon the auxiliary member and exerting a bias thereon.

9. In a speed controlling aparatus, a rotatable shaft, a centrifugal governor driven by said shaft. a bell crank lever pivoted intermedia' e its length and having a depending arm connected to said governor and an upper horizontal arm, means for yieldably resisting pivoting of the bell crank lever in one direction including a primary member shiftable longitudinally of the horizontal arm and bearing against the same, an auxiliary member carried by a stationary support and bearing agains the primary member over the free end portion of the horizontal arm, and spring means acting upon the auxiliary member and exerting a bias thereon.

THEODORE H. BARTH.