US 2623439 A
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Description (OCR text may contain errors)
Dec. 30, 1952 SWINGABLY E. PASKELL Filed July 20, 1950 3/ -F/GURE F /GURE Z SUSPENDED ELECTRICALLY DRIVEN CUTTER DEVICE /NVE/vrof?. Ernest Poskell 5)/ Janna, .g/uen( y@ Z146 AGE/VTS.
Patented Dec. 30, 1952 SVINGABLY SUSPENDED ELECTRICALLY DRIVEN CUTTER DEVICE Ernest Paskell, Columbus, Ohio, assgnor, by mesne assignments, to Battelle Development Corporation, Columbus, Ohio, a corporation of Delaware Application July 20, 1950, Serial No. 174,882
This invention relates to electric motor suspension, and, more particularly, to a novel combination of an electric motor and means for its suspension.
There are occasions when it is desirable to be able to cause an electric motor and a tool driven thereby, such as a rotating cutting wheel, to approach a given object at a speed such that the cutting Wheel upon contacting said object will not rebound therefrom. For example, when a grinding or cutting wheel contacts work that is being rotated, and it is desired to make an extremely light cut in that work, it is necessary that the cutting wheel contact the work very gently and continuously in order to achieve a uniform, continuous cut.
In the past this has been accomplished by vari- Ous hand operated or machine operated, hand actuated devices which cause a cutting Wheel, with or without a motor associated therewith, to contact the desired object. However, where an extremely shallow cut is to be made, for example as low as 1 10-3 cm. in depth, the devices of the prior art are unsatisfactory for such purposes. In fact, cuts of even much greater depth generally cannot be achieved by prior art devices.
Cylindrical film type resistors are frequently spiralled in order to increase their resistance. Quite often the iilm is extremely thin, as low as 1 10I cm. in thickness, and consequently the spiral cutting operation is an unusually difficult one. Devices of the prior art are unsatisfactory for such spiral cutting, due to the fact that uniformity of depth of cut, uniformity of spacing between cuts, and gentleness of contact of the cutting tool cannot be achieved.
It is, therefore, one object of this invention to provide a unique means for suspending an electric motor in combination with a cutting tool actuated by the motor whereby the cutting tool may be brought very gently into contact with the work, and maintained continuously in contact therewith.
It is another object of this invention to provide a support in combination with an electric motor and cutting wheel which will enable the cutting wheel to be readily withdrawn from contact with the work.
It is still another object of this invention to provide a device capable of making a very shallow cut.
It is a further object of this invention to provide a resistor spiralling device.
Various additional objects and advantages of this invention will become apparent from the following drawings, in which,
Fig. 1 is a side elevation view of this device, and
Fig. 2 is a front elevation View of a modification of the device shown in Fig. l.
Referring to the drawings and, more particularly, to Fig. 1, III is a rod-like support, or fulcrum, about which vertical supporting member I2 is free to rotate. Suspended from member I2 is electric motor I3 on the shaft I4 of which (see Fig. 2) is a cutting wheel IG. A stop Il is provided at the upper end of rod I2 beyond the fulcrum I Electric motor I8, which may be suspended or otherwise mounted so that it is free to move in an axial direction, rotates shaft I9 which is supported by and threadedly engages support 2l which is positioned on stand 22. Attached to shaft I9 is chuck 24 which is adapted to secure the work 26 therein. The work, as shown, is a cylindrical resistor which is to be spiralled. Electric motor I8 has a source of supply of electrical energy 2l associated therewith, while electric motor I3 has a source of supply of electrical energy 28 associated therewith.
In the embodiment of this invention shown in Fig. 1, a solenoid 29, provided with a source of electrical current 3I, is positioned above fulcrum Il. This solenoid has an armature 32 which contacts rod I2 and holds rod I2 tightly against stop I l when the solenoid is actuated as shown in dotted outline in Fig. l.
In the embodiment shown in Fig. 2, instead of a solenoid arrangement, the fulcrum I0 is the shaft of an electric motor34 having a source of electrical energy 35. In this embodiment shaft ID and rod I2 are xedly secured to prevent relative movement therebetween. Electric motor 34 is a type of electric motor commonly known as a damper motor which is not damaged when stalled and consequently when rotated in the proper direction functions in the same manner as does solenoid 29, namely, to keep rod I2 in contact with stop I'I.
Fulcrum I IJ is so located with respect to chuck 24 that cutting Wheel I6 while rotating will be forced against the work 26 by the force of gravity. Such dynamic displacement from a freely hanging position will be determined by the desired depth of cut, the size of the particular work being cut, and the weight and size of the motor I3 and cutting wheel I6. For a small resistor, such as is shown in the drawings, ,this angular displacement is less than 1.
Stop I1 is so positioned that when the solenoid 29 or electric motor 34 is actuated, the grinding wheel I6 will be out of contact with the work 26 and also out of the way so that the work may be positioned in chuck 24 or removed therefrom.
While member i2 has been disclosed as a rigid member it is understood that coming within the purview of this invention would be a flexible member, andinsteadof a solenoid member 29 or a damper `motor 3A, an electromagnet (not shown) which would cooperate with electric motor I3, could be used to hold that motor outof contact with the work 26.
The operation of this device .is :as follows: When the grinding wheel I6 is at `res'tfand'not in contact with the work, itis held-.out of Ythe immediate vicinity of the work,eit-her -by vsolenoid 29, or in the modication fshown in-Fig. 2, byI motor 34. This position of motor I3 and grinding wheel I6 is shown in dotted outline in Fig. 1. To operate the device after workhasibeeninserted in chuck 24 the current to the solenoid'` 29 ,or to motor 34 is turned oiwand simultaneously motor I3 is energized. Motor I3 Ais so positioned that theiorceexerted by .its vstarting torque 'Itends to moveit in a righthanddirection, as shown .in iig. 1. Consequently, while ,the force of gravity `ais/toiildtendito make motor 'I3 move tothe left, as Yas'howrrin solid Voutline in '1, the starting torqueof fthe motor will overcome the force of .gravityrand'tend to movethe motor in a righthanfd direction. 'I-Iowever, the motor and assoplated .grinding wheelcannot move in a right- "han'd vdirection "because stop I"I prevents this. Therefore, the motor and associated grinding whelare'held in equilibrium asthe motor comes ,up 1:0.spee'd .and unti'lthe starting torque decreases. [As the startingtorqueforce .decreases `lit-.eventually ldecreases to a Vpoint where it vis lbalancedby thecforce of lgravity vtending to move the Agrinding wheel andmotor associated therevWithin a 'left-hand. direction. 'Since the starting 4fulcrum on the opposite side of rod I2.
,torquedecreases gradually 'in ahigh-speed elec- ;-motor, the,grinding wheel and Vmotor will yerygently and very graduallytend to move in `ra`left-han`d direction as the force of gravity over- :cornes the lforce exerted 'bythe starting torque. Iheneit result Yis'toiloring the grinding wheel .I6 .intoveryugentle contact'w'ith the work 25 which uisbeing revolved by motor I8.
'LThe reason'that stop 'I'I Vis employed is because thestartingtorque is sogreat that the motor and grinding Wheel would be moved so farina righthanddirectiomas shown in Fig. .1,'that'vvhen the startin'gtorque'is diminish'ed'the force of gravity would' bring the 'grinding wheel into abrupt con- ;tactyrith .the work .2.6. ..1-Iowever, 'by using stop "I'Iian'd determining itsposition by the degree of .force exerted 4by the starting torque of Ythepar- 'ticular motor employed, andthe `size ofthe worl: bein'gspiralleda very gentle :initial 4contact will fberea'lized and 'a' very 4gentle cutting ContactV will ibe maintained. Such a motion :is essential in spiralling resistors 'of extremely'thin skin -or 'film thickness Whenthe desired cut has `b'eenimade inthe 4-workfit only necessary byV a 4simple switching arrangement gto cut oil' the vsource'of electrical vlenergy tofth'e `motor I3 and 'simultaneously to .supply `electrical energy to Veither Imotor 513 or solenoid "29 whereby the cuttingwlreells will rbe .instantly removed `from the work, and ithework Ymay Athen lbe removed from .chuck 24, and be "replaced by new Work. Electric motor `I 8 then'has its direction reversed until the right=handiendof the work 26 is properly aligned with cutting wheel "T4, 'and the =cutting procedure Ais :then .re-
O'f course, if 'anon-rigid .rod I2 is used `to .llt;shouldjbe..apparent from the above descrip- '-jtionz'thatthe utilization of this invention results in obtaining work having extremely ne cuts therein. `Whena. resistor, such as a carbon lm vresistor,havingfan extremely thin lm thereon is to be spiralled, tthis invention may be utilized in the spiralling thereof and will enable an extremelyfshallowput to be made in the film of mthe resistor, and will prevent chipping of the resistive film at its initial contact with the rotatingrgrinding wheel.
"mile-this invention fis g particularly suiterl I.to the lspiralling of fresist'orsiit `is Ato "be understood *thatlits functions vare 'not limited thereto and that this particular unique suspension mechanisminicombination with an electric motorand cutting wheel operated lthereby is applicable 'to many other uses where a shallow controlled cut is to be ina-demand itis desired thatthe rcutting tool initially contact'thework in a very gentle Vmanner.
`Wliile-this invention Yhas been described/in its preferred-embodiment it is 'to beunderstood-that *the 'words Lused are words 'of description rather than jof limitation 'and that changes within 'the purview Y'ofthe'appended claims maybe made Without departing from the true scope and spirit 4of the invention.
*What-is claimed *1. A ycutting device,` including va. cutting means v `for making an yextremely light fout, with a lvery gentle vinitial contactotthe'cutting means, on
'an article, and-comprising rotativev motormeans iandcutting means'dri-ven'by said motor mea-ns, Ya"fulcrum,said motor y*and cutting means being 5 freely --suspended ffrom' said fulcrum, means *for selectively lpreventing `said cutting means and -said motor -means from assuming a suspended position ldependent'solely on the vforce of gravity,
`and Vmea-ns for -limiting the movement of said vcutting means and said motor means lto 'a suspended position other than Vthat 'suspended'posi- Ytion whichis idependent solely on the force vof gravity, said "motor means Vbeing so positioned that upon starting, its Astarting torque-Will vcause the-motor means tomove away from a suspended position which would n'bedependent solely on Vthe -f force Aof gravity.
f2.1The Ystructure Aset fforthjin claim '1, wherelin said motor Irmeans comprises an electric motor,
and wherein said cutting means is a rotative "cutting'means '3. Thestructure set forth in claim l, wherein said motor means is an electric motor, tand whereinsaideutting means is a cutting'whee'l.
-in saidjmotor Vmeans is .an electric motor, said l'cutting'nleans is "a cutting wheel,'and wherein rigid means is ,provided which is rotatably 'securedto'and depends from said'fulcrumfsaid motor and said `cutting Wheel being freely suspended from said fulcrum by said rigid means.
i5. The structure Vsetiforth in claim 1, wherein said motor means `is an `electric motor, Aand "wherein said means *for selectively ,preventing said cutting means 'and-said Velectric motor from assuming a suspended position dependent solely upon the force of gravity is a solenoid means.
6. The structure set forth in claim 1, wherein said fulcrum comprises a shaft, and wherein means is provided for applying torque to said shaft, said motor means and cutting means being suspended from said shaft in substantially rigid relation thereto.
7. A spralling device, including a cutting means, for making an extremely light cult, with a very gentle initial contact of the cutting means, on the surface of cylindrically shaped work, and comprising means for detachably holding said work, means for simultaneously rotating said work and eiecting relative movement of said Work and said cutting means parallel to the axis of said work, rotative motor means and cutting means driven by said motor means, a fulcrum, said motor and cutting means being freely suspended from said fulcrum, means for selectively preventing said cutting means and said motor means from assuming a suspended position dependent solely upon the force of gravity, and means for limiting the movement of said cutting means and said motor means to a suspended position other than that suspended position which is dependent solely upon the force of gravity, said motor means being so positioned that upon starting, its starting torque will cause the motor means to move away from a suspended position which would be dependent solely upon the force of gravity.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS