US1829311A - Apparatus for investigating and demonstrating the laws of centrifugal force - Google Patents

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APPARATUS FOR INVESTIGATING AND DEMONSTRATING THE LAWS OF CENTRIFUGAL FORCE Filed May 28, 1929 INVENTOR BY W .1 4 {:7

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' Patented Oct. 27, 1931 rn'rnn Ii. or YONKERS, NEW YORK n rffeana'rus FOB rnvns'rrenrme AND Application filed May 28,

a This invention relates to an apparatus for investigatingand demonstrating the laws of centrifugal force,

An object of this invention is to provide a simple, inexpensive and efficient apparatus suitable for use in schools, classrooms and elsewhere, whereby to demonstrate the laws of Centrifugalforce-that is, that the force is radial for uniform rotation, that the force is,;proportional to the radius, and that the force, is proportional to the square of the revolutions per minute.

An apparatus embodying the invention comp'rises a rotating arm or bar, on one end ofz' which is carried a horizontally pivoted and :balancedmember intowhich is screwed a vertical member. When the bar is rotated, the centrifugal force causes the vertical member to; tilt and the force necessary to do 20 this-is easily measured. At the other end of the rotating member is carried a member capable of swinging freely in a horizontal plane, which acts as. a counterweight and when the bar is rotated, follows the direction of the centrifugal force, thereby demonstrating that the force is radial.

Other objects, novel features and advantages of the invention will be apparent from the following specification and accompanying drawing, wherein: a i a The figure represents a perspective view of an apparatus embodying the invention.

a 10 indicates the base of the apparatus, on. which, is supported a housing 11, and within the housing is arranged a spring motor 12 which drives the shaft 13. mounted on the bearings 18 On the upper end of the shaft 13 is supported an arm or bar 1 1. At one end of: the barl t is mounted a frame 15 slidably:

so. aifixed thereto, its position on said bar beingfixedbythe thumb screw 16. The frame 15 carries a pivoted and balanced member 17- which is normally horizontal, being balanced on the pivots 18. Into the end of the member 17 nearest the axis of rotation of the bar 1 1 is screwed a vertical piece 19 DEMONSTRATING THE LAWS OF CENTRIFUGAL FORCE 1929. Serial No. 366,686.

zontal position of the member 17 when the piece 19 is screwed therein is maintained by the adjusting screw 20. When the member the member 17 will cause the member 1'? to strike the piece 20*, making an audible sound.

The position of the member 17, when the piece 19 is not mounted on one end, is normallyhorizontal and in this position it is balanced both for gravity and for centrifugal force. The member 17 is preferably made of aluminum or other light metal to minimize the effect of slight error in locating the pivots 18 at the proper geometric axis of symmetry of the member 17.

On the other end of the bar 1 1 is mounted a frame 21, also slidably affixed thereto, its position on the bar being fixed by the thumb screw 22. The frame 21 carries a member 25 which is of a weight suficient to serve as a counterweight and is mounted on the arm 24- and is pivoted about the screw 23 which permits the member 25 to rotate freely in a horizontal plane. A slit or other mark 26 is placed at the center of the bar 14 and at its axis of rotation, to permit accurate measurement of the radius to the center of the vertical piece 19; and at the two ends of the bar 14 are placed the bolts 27 or other obstructive instrumentalities to prevent the members 15 and 21 from flying off the bar 14 when rotated.

The above described apparatus is made use of as follows: The bar 1 1 is caused to rotate by the spring motor 12, the speed of rotation being regulated as desired. As the speed of rotation increases, the centrifugal force caused thereby increases, until it becomes sufficient to tilt the members 17 and .19. Due to the balance in the member 17 in the normally horizontal position which is set by the adjusting screw 20, the weight of member 1? as well as the centrifugal force acting on it will be balanced, and the centrifugal force required to tilt the members 17 and 19 will beonly that which is necessary to tilt the.

member 19,'Wll3ll which the investigator need only be concerned. Although the tilting force will decrease as the combination 17 and:19'

tilts, it is only the initial force required to tilt the COIHbiIiatlOD-in which- :the. observerneed be interested, for the purpose o1? demonstrating'" "the laws of centrifugal. forcem, *The'centrifugal force necessary to tilt the combination 17 and 19 can thenbe measured hea -h pp ra is epr drby-pes na i string around the center of the verticalpiece 19 and tying the other end to a combination spring and ruler or othermeasurin-g, instru:-. mentality, and notingthe force' required to tilt thecombination=17 and- 19 h handy-the coinbinationaspring and ruler being pulled in as nearly a horizontal-direction as possible and in i a; direct-ion which: would intersect the axis of rotation oi the bar 114: J By moving the frame 15 along the bar 14, the radius can'lbetvaried and' by varying the revolutions per minute ofthe spring motor 12, the rotatibniof theb'ar 14 may be likewise varied; and" a-fterQtaking a number of read:- ings of the eentrifugaliorce necessary to tilt the combination l'zand 1 9the observer will note that nthe centrifiigal forcerequired-Will vary proportionally with the radius, and with the square "of the revolutionsjp'er minute,-

- Likewise, by':va rying" the height 'ofthe memobserver mayirote'the efl 'ect' on the centrifw galriorcerequired "to tilt the combination 17 and 19.

As the 14' rotates, the combination 21' to25 mountedon the other end of sa id bar 14;, being of su fli'cient Weight, serves as a counterweight to approximate dynamic .-b'al-- ance, andno matter in" What direction th e' arm 24 is pointed initial ly, it will point ra- I dial'ly when" the speedof rotation-of the bar let is l1ni1 OFn1 -Wi-tl l'th6'HHISS' 25'- at tliegfarth est distance from the axis of rotationfrom which action it is demonstrated that'cent'rif' u'g'al force is'rad ialp Further experiments withthe comb1nat1ong2 l -25 may, be v perg formed to demonstrate this"law" as,"for intance, on a sudden stopping of the bar with the hand or-otherwise, the combination}, 2st and will rotate. about the bearing {from the furthestradial positionin the same direction of rotation'as the bar 14 (combina-j tion 24- and before the bar 14 Was stopped.-

The revolutions permin'ute'of this apparatus need only range between 25 and 120, Which-is a suliicientrange to show the 'efi'ect of revcflutions:perv minute on centrifugal force action and the maxiniumrevolutions perminute (120) "is solowthat no dangerpcan follow due to-theloosening of anypiece. f

' By meansflof theabovedescribed apparatus, the: laws. of centrifugal force may be simply andaccurately checked; The entire ,7

those "specific all ydescribed.

Ielaim p ,1. .Inan apparatus, for I demonstrating thc laws of centrifugal name, a rotatable support, a radially arranged lever pivotally mounted on said support, said lever extending toward and terminating short of the axis ofsaid support, a Weight carried'i by 'lthe inner' end of said lever; andimeans limit movement "of said inner end of lever :toWard-said'support," r. a I n 2. In an apparatus ffondemonstrating the laws of centrifugal force, a rotatable, sup: port, a radially}: arranged lever pivotally mounted on said supporh zsaid lever extend ing toward and terminating short-oat the axisj of said s upportyfa weight earried by the inner endof said leve'r, means tosupport the inner end of said lever; sa-idleverj and gvveight being so mounted Zas' to oppose solely by gravitation the; action of centrifugal force-- 33 In; an apparatus for demonstratingethe laws of centrifugalforce, a) rotatable sup port; a" radially 1 arranged "leverpivotally mounted on said? support',{fsaid lever" extend-"- ing toward and terminating short of the axis r ofsaid, support," means for radially'adjuste mg "sai'di lever, a weightcarried by? the inner end of said lever; and means to limit move ment or said innerend'of said lever towalfd said support;

4.- In apparatusfordemonstrating tlie;

laws of centrifugal;;force, a rotatable 181%) port, a radiallyfarranged lever pivota 'y mounted onsaictsu-pport,saidlever extend?- I ing" toward and terminating short of the axis of said support, means for radiallyjfajdjust in'g said 'l'e'ver,-a Weight "carried by't he inner end of said lever, means to sup-port? the inner" end of said l'ever', s'alid lever and Weightbeihg so mounted as to oppose solely by gravitas tion mention- 0f centrifugal force; r r; Y

g5g 1n an;apparatus forfdemonst'rating" the; laws" of centrifugal "force, a rotatable slips; port, ,7 a radially arranged lever V pivotally mounted onf'one endf'jof -said support, said lever Q extending toward? and t'erInin'atiirg;

short of the axis of said support, a weight,

carried byt'he inner en'dof said lever means to limit movement ofsai d-i nner of, said lever towardjsaid support, and a counterweightlrotatably mounted on the other end, of aidsupportj j 4 a In y; ri ofifl "hey 'gliedili 'y" nameltotliislspecification.

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