US1818826A - Speed responsive control - Google Patents

Description

SPEED RESPONSIVE CONTROL Filed July 27, 1929 4 Sheets-Sheet 1 by his affarlwys MMWM Aug. 11, 1931. Y w, T, TABB 1,818,826

` SPEED RESPONS IVE CONTROL Filed July 27. 1929 4 sheets-sheet 2 Warner 7'.' Tabl,

by his aawzeys Aug. 11, 1931. w. T. TABB SPEED RESPONSIVE CONTROL Filed July 27, 1929 4 Sheets-Sheet 5A lNvENoR Warner T. Tabl,

Ms' czfarneys Y Aug. 11, 1931. w. T. TABB SPEED RESPONSIVE CONTROL Fiied July' 27. 192s 4 Sheets-Sheet 4 INVENTOR Warner T'. Tabla,

55! Malforngy: *i

resented Aug. 11, 1931 UNITED STATES PATENTE OFFICE WARNER T. TABB, O F MAHWAH, NEW JERSEY, ASSIGNOR T0 THE EISEMANN MAGNET() RPOBATION, OF NEW YORK, N. Y.. .A CORPORATION 0F NEW YORK SPEED'RESPONSIVE CONTROL;

Application :Bled J'uly 27,

This invention has to do with speed responsive devices. l Its underl ing thou ht is to utilize, as the source o energy or causing the performance of the function that is to respond to a certain speed, the vibration of an element which has a predetermined natural frequency and which is set in motion by the vibratory motion of another element whose frequency varies with the speed to which the device is to respond.

` The vibrator thus set in motion is caused to do work, by means of a suitable connec-V tion, either in controlling the supply of energy to the machine whose speed it.

responds to, as in the case 'of a governor, or in operating some separate instrumentality having a function which it is desired v to relate to a certain speed or range of speeds of the said machine.

It will be apparent that the device may be put to various uses. As an illustration, chosen because it is the best known and because the invention was developed with reference particularl to this use, the invention is. described hereln as used to govern the speed of the machine to whose speed it responds and, in particular, as it is used to govern the s eed of an internal combustion en'gine by utilizing the pulsations of the gas How through the intake line of the engine to set in motion a vibratory element connected to operate a throttle valve in the said intake line. It is to be borne in mind however that the invention in its broader aspects has many other fields of ap lication which are not to be deemed excluded by this description of the invention as applied to the problem of governin I t is important to distinguish at the outset, the form of the invention to be described here from the known suction governor which depends upon the mean eective value of. the suction for operating the controlling valve and upon the variation of this value with the speed of the engine. Such variation is not a very close function of the speed variation since it depends upon the load and upon other factors to a very material degree. The governing thereby effected is not as accurate or as satisfactory gener- 1929. Serial No. 381,631.

illustrated in the accompanying drawings and are described hereina ter with reference thereto.

In the drawings- Figure 1 is a view, partly in section, througha unit consisting of a rotary valve, a vibrating element and a ratchet driven differential ear for translating the motion of the vibra-tlng element into a motion of the valve.

Figure 2 is a view in section on the line 2-2 of Figure 1 but with the vibrating element shown in elevation and withthe outer ratchet partly broken away to show the planetary gear and the inner ratchet.

Figure 3 is a lview looking into the end cover at the right of Figures 1 and 2 and showing the vibrating element in elevation.

Figure 4 is a plot of amplitude of the vibrating element against engine speed showin a characteristic action of a goveernor o `the type shown in Figures 1, 2 and 3.

Figure 5- is a view, partly in section, of a similar governor unit having aemodified form of device for operating the valve from the vibrating element.

Figure 6 is a sectional view of the same modified unit, the view being taken in a plane at right angles to that of Figure 5.

Figure 7 is a v1ew, partly in section, of a like unit with still another device for actuating the valve from the vibrating element.

'Figure 8 is a sectional view of the same unit in a plane at right angles to that of Figure 7.

In the form of governor shown in Figures 1 and 2, the governor valve 10 is mounted between the carburetor and the manifold in the intake line 11 of an internal combustion engine which may be assumed to be of the four cycle type in which each cylinder exerts a suction effort in the intake once for every two revolutions. The valve has a permissive movement of 90 between open and closed positions, being turned by a spindle 30 extending outside of the intake line and into the governor casing 12 where it carries a ratchet actuated differential gear drive mechanism for turning it in either direction. This mechanism consists of two bevel gears 13, 13', free to turn on the valve spindle and inmesh with a planetary bevel gear 14. carried by a stud on a frame 15 that is mounted to turn bodily with the valve spindle. These gears have oppositely acting ratchet wheels 16, 17 secure to them, by ,means of which the?7 are turned as the ratchets are actuate by their respective awls 18, 19. The two lugs 34 spaced 90 ie in the path of the stud 35 and thus limit the turning of the valve.

The vibrating element is mounted in a hemispherical casing 2O which rests against the bell end 31 of the casing for the valve actuating mechanism just described. This element 1s in two parts, each part being a` semi-circular piece of thin resilient metal 21, 22 havin a weight 23, 24fastened to it j on. each si e near the periphery. These 6 the wheel so as to ull on t semi-circular pieces may be integral or separate but in either case they are clamped 1n' the mid area of the element by diametral members 32, but otherwise are free. The curved edge of each semi-circular disc just clears the wall of the casing which is formed as a true hemisphere in the region 33 of the. vibrating element in order to provide a substantially constant clearance for all positions of the vibrating element. The diametral clamping members 32 are supported from the casing by webs 25 and are held together by bolts.

The pawl 18 for the ratchet 16 is connected to the weight 23 by a free pivotal joint, the end of the pawl engaging a pin extending across a slot in one of the weights 23, and the pawl 19 acting on the ratchet 17v is similarly .connected to the weight 24 the pawls being also supported by their en"- gagement with the ratchet wheels. The Eawls are two pronged, one prong of each eing bent inwardly to engage between adjacent teeth of the ratchet wheel and to ush forward while the other prong is slotte and the slot 37 rests over the o posite side of lie teeth of the backward stroke. n order to cause o site rotation of the ratchets, the pus ing prong of one pawl 18 engages its ratchet on the upper side and the slotted pullin pawl 05 engages on the -under side, while lin t e case vbias toward open is not necessar'.

ofthe other pawl 19, the pushing prong acts on the under side and the pulling awl on the upper, the teeth Aof the two ratc ets being oppositely directed. (See Figure 2.) Thus oth pawls push on the ratchets when they swin toward them and pull on them when moving back, causing rotation of the two in opposite directions. The direction in which the valve stem turns depends u on the net eiect of the two ratchets aecordm to the known principle of such diierentia gears, since both ratchets act on the planetary gear 14 through their respective bevel gears and when one ratchet turns faster than the other it causes the planetary gear V14 to roll on the bevel gear of the slower ratchet and hence to carry the frame 15 and spindle around with it.

The chamber in which the vibrating element is mounted is in communication with the intake 11 on the engine side of the valve 10 by way of a passage 26 through the casing wall. By reason of this fact, the two vibrators making up the vibrating element are subjected to the influence of the pulsating gas, the frequency of whose vibrations or pulsations varies directly with the speed of the engine. There may be a coil spring 36 connected to the spindle and to the casing to stabilize the valve and to give it a normal gosition but such a spri uch a spring may be use also to provi a means of adjusting the governing speed.

The two vibrators are so made that they have different natural periods of vibration. The period being a function both of the resiliency of the thin disc and of the weight, this difference is easily brought about and still is made capable of ready change byusin identical pieces of resilient metal but with dierent movable weights on them. Further, the natural periods of these weightspring combinations is of anorder of magnitude corresponding to a frequency about equal to the frequency of the gas pulsations caused by the engine speed that 1s the desired maximum.

As the frequency of gas pulsations increases and ap roaches the natural frequency of the v1 rators, it induces a vibratory motion thereof. The vibrating part of lower natural fr uency is connected to the ratchet which ten" to open the valve while the other is connected to the valve closing ratchet. When the speed is such that the vibrator of lower natural frequency attains its naturalfrequence and hence its maximum amplitude the other vibrator is vibrating with a shorter amplitude as it is not at its natural frequency, and thus the net effect of the two is to urge the valve toward and to maintain it in its open osition. A higher speed, beyond that giving a pulsation frequency equal to that of t e natural Vfrequency of the part of lower natural frequency, the amplitude of the said part decreases while that of the other vibrator continues to increase as it approaches itsnatural frequency. It finally dominates and then the net effect of the whole vibrating element is to close the Valve.

This action is illustrated in Figure 4 which is a plot of the variation of amplitude with variation of the frequency of gas pulsation or, in other words, with the engine speed. The amplitudes are of the two vibrators as induced by the gas pulsations, the upper curve A being that of the vibrator of lower natural frequency while the inverted curve B represents the vibrator of higher natural freuency. The inversion is to represent the di erent directions in which the two elements act, one opening, the other closing the valve. The broken line curve C represents the net effect of the two or the effect of the two vibrating elements as a whole. By changing the weights and the spring discs, the curves may be made fiat or sharp as desired, a heavier weight with a correspondingly stiff spring giving a sharper turning for any given natural frequency.

It will be understood from known physical laws that in addition to the curves shown,

a plot of the amplitudes over a greater rangeA of frequencies of the inducing vibrations would show other curves representing harmonies. These, however, are much weaker thanthe vibrations at the fundamental. The half tone of the opening part and the overtone of the closing part, of course, would give a desirable effect. properly designed element in which the strength 0f the springs is such as to revent vibration of material amplitude at tlie harmonic without preventing substantial vibration at the fundamental, the net effect of the two parts at the harmonic is negligible. Tt is even possible to make the difference between the natural frequencies of the two vibrators such that the half-tone 7 of the one of hi her frequency comes while the other one 1s havin a substantial amplitude at or near its fun amental and sufficient to overcome the half-tone.

In place of the pawl and rachet drive connection with a planetary gear, for operating the valve from the vibrating elementby converting the vibrato'ry` motion into cumulative motion in either direction, many other mechanisms may be used, either electrical or mechanical. A suitable mechanical modification is shown in Figures 5 and 6. The vibrating element is in the form of a piston- (pring combination. A piston 40 is mounte in a cylinder 41 and is of slightly smaller diameter than the cylinder. The piston is held between two similar springs 42, 43 put under initial compression and bearing against opposite sides of the pis- In any event, with a ton and opposite ends of the cylinder. Another spring 44 is attached to one side of the piston and rests at its other end on a threaded plug 45 which passes through the cylinder wall and whose threads have the same pitch as the turns of the spring so that it may be moved into and out of the coil to limit the effective length of the latter.

There is also in this modification a different mechanism for translating the vibration of the piston into uni-directional rotary motion of the valve spindle. This mechanism consists of a yoke 46 directly connected to the piston and provided with a stem 47 at its other end sliding ina bearing 48 in the casing. This yoke (mounted over the cam 49) which is fixed on the valve spindle 50 has bumpers 51, 52 preferably of hard fibre or some similar substance mounted at diagonally opposite corners in position to engage the cam faces 53, 54 alternately. These faces are portions of a curve which may be the involute of the circle of the valve stem. They extend for 180 each, ending in radial faces 55, 56. A pin 57 on the valve stem turns in a recess 58 which is a quarter segment of a circle and thus limits the movement of the spindle to 90.

Since there is but a one-part vibrating element and a uni-directional motion translating device, the valve in this modification must be urged toward open position by a coil spring 60 attached to the outer end of the valve stem and to the casing wall. The valve therefore normally is in open position. It is possible, of course, to apply the thought of the previously described modifications by providing two cams and two oppositely acting piston-bumper sets of different natural periods, one acting to open the valve and the other to close it.

As the piston is given a vibration of substantial amplitude when the frequency of gas pulsation in the inlet, communicated through the passage 26, approaches the natural frequency of the piston-spring device, the bumpers act on the cam faces 53, 54 and by their cumulative effect cause the valve stem to turn until the valve is closed. The adjustable spring 44 permits the tuning or governing speed to be varied as its effect is to change the natural period of the vibrating element, of which this sprin is a part, corresponding to the weighted resilient discs in the other form described above.

As still another variation illustrating the many possibilities that there are of varying the particular construction of the elements of this invention, there is shown values, the result being two vibrators of different natural eriod of vibration. The discs are clampe on a diametral web 74 by a bar 75 held thereto by bolts 76. The vibratory motion is translated into rotary motion by a neumatic motor made u of a cylinder 77) with a piston 78 sli able. therein and check'valves 79, 8O opening respectively from the diaphra m chambers 81, 82 to opposite sides of: the piston. A partition 83 integral with the web 74 forms the valve head and separates the diaphra m chambers from the interior of the cylin er 77. A passage 84 leads from the discharge side of the valve to the outer end of the cylinder while the valve 79 opens directly to the cylinder, thus giving separate .outlets from the two dia liragm chambers to opposite sides of the piston 78. The piston is connected to the valve stem by a rod 85, extending through the web 74 and by a crank 86 and connecting rod 87. There is a stabilizing spring 88 on the end of the valve stein tendin to hold the valve open and to hold the piston at the right hand end of the cylinder, but it isnot necessary with the two-part double acting vibrating element. A in 89 and quarter circle recess 90 limit the permissive turnin of the valve.

As t e two parts of the diaphragm are set in motion by the pulsations of the gas in the suction inlet as communicated to the diaphragm chambers 81, 82 by the assage 26, the vibrators discharge the gas t rough the valves 79, 8O and thus build up pressure on opposite sides of the piston. The vibrator 70, 72 of lower natural frequenc causes the gas to be delivered past the va ve 79 from the chamber 81 to the left hand side of the cylinder while the other vibrator delivers gas past the valve 8O to the channel 84 which leads to the other side of the piston.

As in the case of the form shown in Figures 1, 2 and 3, the vibrator of lower nat ural frequency exerts an effort tending to hold the valve open and dominates until the frequency of pulsation exceeds its natural frequency, whereu on its amplitude decreases and that o the other vibrator increases since the latter is being brought to its natural frequency. A point is reached at which the latter vibrator dominates by reason of eater amplitude and greater pumpinge ort and the result is a movement of the cpiston 78 to the left, turning the valve towar closed position. As the speed decreases upon t rottling, the effect of this higher frequency vibrator decreases and the valve 1s again opened Aeither part way or wholly. The governing continues in this.``

vwa lt will be evident that the type of-vibrating element may be varied and that different expedients may be adopted to convert its vibratory motion into a cumulative motion suitable for a valve. There may be a twopart vibrating element acting to open the valve over one range of pulsation frequencies and to close it at another, or there ma be a single vibrator with an opposing orce' such as that of a spring. For the element that induces the motion of the vibrators of e electrical systems, all of which involve4 some vibration or pulsation that varies in frequency with the speed of the engine and therefore may supply the energy and periodic eiect which induces andmaintains the motion of the vibrators.

The motion of the vibrating element may 4be utilized in various ways to act on the valve or other device-directly or to act on a pilot or relay mechanism as is a common thing in other controllers of valves, switches and the like.

The mechanisms described here are illustrative of the underlyin principle and of simple, effective ways o putting it to use. It will be appreciated that there are many other forms, some of whichI involve complications such as phase diifeiences between the maximum or minimum effort of the iny.

ducing medium and the position of the induced vibrator in its path. In some cases these phase differences may be utilized and in others they mayl be com ensated for. Such forms present elds for t e application of ordinary skill or of further inventive effort within the scope of the broad invention here disclosed. I wish to include therefor within the scope of protection 'ven by a patent all suchmethods and mec amsms as come within claims.-

I claimy o 1. A speed responsive device comp A a vibrating element having a predetermm natural period of vibration, means for sub- ]'ectn said element to the influence of .pulsating with a frequency v a ing with the speed under concern to in uee sympatheticv vibration of said element, and means for utilizing the motion and energy of said elementwhen vibrating at and near its natural' eriod to cause the perfomance lof the spee responsive function.

'2. A speed responsive device comprisii'g a vibrating element having a predetermin natural period of vibration means for subjecting said element to a vibration inducing miluence having a frequency of vibration the .fair range of the following for subjecting said element to a vibrationv inducing influence having a frequency of vibration varyin withthe speed under concern, and means or utilizing the motion and energy of said element whenvibrating at and near its natural period to cause the speed responsive function to be performed.

4. In combination with 'a prime mover,

means for controlling the supply. of energyA thereto, a vibratory element havin a redetermined natural period of vibration, means for subjecting said element to the inluence of pulsations Whose frequency varies with the s ed of the prime mover to induce sympathetic vibration of said element, and means actuated by said element when vibrating for operating said controlling means.

5. The method of performing a function, in response to a part of the speed range of a mechanism, which comprises settin a primary medium in vibration with a requency varying with the speed of the said 80 mechanism, causing said medium to induce vibratory motion of an element havin a natural period of vibration within t at' range of frequencies of said (primary element which corresponds to sai part of the speed range, and utilizing the motion and energy of Ysaid element when vibrating to cause the performance of the speed responsive function.

6. In a speed responsive governor, a valve and valve closing mechanism, a chamber with a vibrating'element therein having a predetermined natural period of vibration, provision for utilizing the energy of said element when vibrating to operate said valve closin mechanism and means for subjecting said e ement to a vibration inducing influence having a period of vibration varying with the speed controlled by said valve.

7. In a speed responsive governor,a valve, a vibrating element having a predetermined period of vibration, means for subjecting said element to a vibration inducing influence of varying frequency, and provision for converting the vibratory motion of said ,element into cumulative motion effective to operate said valve. A

8. In a speed responsive overnor, a valve casing, a valve therein an valve operating means, a chamber and a vibrating element therein having a predetermined natural eriod of vibration, together with an inlet rom the valve casing to said chamber and provision for utilizing the "energy of said element when vibrating to operate the valve operating means.

9. In a speed responsive device, a vibrating element comprisin a weighted spring, means for subjecting said element to a vibration inducing influence having a frequency varying with the speed under concern, and means for utilizing the ener y of said element when vibrating to perfgorm the speed responsive function.

10. In a speed responsive device, a vibrat-v ing element comprising a piece of resilient sheet metal and a weight carried thereby, means for subjecting said element to a vibration inducing influence having a frequency of vibration varying with the speed under concern, and means utiliz-ing the energy of said vibrating element to perform the speed responsive function.

11. In a speed responsive device, a chamber having a wall portion conforming to a part of a sphere, a semi-circular piece of resilient metal mounted to vibrate with its curved edge free and close to said wall portion, aweight carried by said piece, means for subjecting said piece to a vibration inducing influence of varying period of vibration, and provision for utilizing the energy of said weighted metal piece when vibrating to cause the' performance of the speed responsive function.

12. In a speed responsive device, two vibrating elements of different natural periods of vibration, mechanism for performing the function responding to the speed under concern, means for utilizing the energy of one element when vibrating to actuate said mechanism and for utilizing the energy of the other element when vibrating to restrain the performance Aof said function, the two elements being subjected to a vibration inducing influence having a frequenc of vibration varying with the speed un er concern.

13. In combination with a prime mover, a control for the supply of energy thereto, two vibrating elements of different natural periods of vibration subjected to a vibration inducing influence having a frequency of vibration varying with the s eed of the prime mover, means utilizing t e vibration of the element of higher natural period to cause said control to stop the supply of energy and means utilizing the vibration of elementA of lower natural period to cause the control to permit the supply of energy.

14. In a speed responsive overnor, a valve, a chamber with two vi rating elements therein of different predetermined natural periods of vibration, means utilizin the energy of the element of higher natura periodl to close the valve and means utilizing the energy of the other element to open the velement tuned to vibrate at a pre 15. A speed control device comprising eterm frequency, means for directly subjecting said element to the inliuence of a gas tplulsatin with a frequency varying with e spee to cause sald element to vibrate when its l pulsations correspond to the frequency of said element, s eed controlling means and means for utilizing the motion and energy of said element when vibrating to cause the operation of speed controlling means.

16.' A speed control device com rising an element tuned to vibrate at a pre etermmed fre uency, means to subject said element to a v1 ration inducing influence having a frequency of vibrations varying with the speed to be controlled2 said influence being effective to cause sald element to vibrate when its frequency of vibration corresponds to the vibration frequency of said element and ineffective at other frequencies of vibration, speed controlling means and means for using the motion and energy of said ele ment when vibrating to control the operation of said eed controlling means.

17. A spee control device com rising an element tuned to vibrate at a pre etermlned fre uency, means to subject said element to a v1 ration inducing influence having a frequency of vibration varyin with the speed to be controlled to cause said element to vibrate when its frequency of vibration corresponds to the frequency of vibration of the element, speed controlling means and means for utilizing the motion d ener of said element when vibratin t cause t e operation of said speed contro means.

18. In a speed responsive overnor a valve, a vibrating element tune to a pi'edetermined frequency, means for subjecting said element to a vibration inducin influence of varying frequency, said vi ration inducing iniiuence being effective to vibrate said element when its frequency of vibration corresponds to the vibration frequency of said element and ineffective at other frequencies of vibration, and provision for converting the vibratory motion of said element into cumulative motion eective to operate said valve.

In testimony whereof I have signed my name to this specification.

' WARNER T. TABB.

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