US1716789A - Zest available copi - Google Patents

Description

June 11, 1929. E. J. MISSIEN 1.716.789

METHOD OF AND MEANS FOR CONTROLLING RECIPROCATING MOTORS Filed March 5, 1924 2 Sheets-Sheet 1 INVENTOR June 11, 19 E. J. MISSIEN METHOD OF AND MEANS FOR CONTROLLING RECIPROCATING MOTORS Filed March 5, 1924 2 Sheets-Sheet 2 INVENTOR Patented June 11, 1929.

' F A TES P T.

1,716,789 E-NT oFFicE.

EDWARD .J l' hli siiEN OFEEfIITSBURGiH, VI-IELNNSYLIVANIA, ASSIGNOR TO CENTRAL ELECTltIC TooLeQ rANY, A CQRPORATION or PENNSYLVANIA v A ND ME ANS FOR CONTROLLING RECIPROCATING MOTORS.

This a pplication is{continued part from "application Serial No,"414,520 "filed Feb-' ru'aryj 1'2, '192 1,relating to electric mechanism, and in part'from applicat'ion' Serial to 'rnet h'od's of operating electric; tools.

: My" invention rel'at'es to electromagnets 5 and means for etintrdlli'ng 5 the sa me, -and particularly cc e l c'trdr'fia'gn ts om rising a I fmovableelement tha 'c'urrent' supplied to the electromagnet in ac-- cordance -iyithf-tl i of the electro of control involved issusceptible? of -ap'pli-- V the-hammer winding caused by the movecation for 'cdnti olling 'electrtimagnet's' applied -'to', or employed for other purposes or uses.

My invention provide's a;- novel 'system' for the voltage across the circuit or the current controlling a reciprocatingmotor? In operating electric hammers of the type n which aneleetromagnet'is per odically energized to reciprocate its core' member- 3.; against atoo'lor"other-device to fdofuseful work, eurr'ent controlling switching devices, such as mechanicalvibrators,"have been em-' ployed, embodying relatively fm(iv-able I contacts i' ir," iii. 1 'f ::'''r I--.

VVhet-her direct current or alternating currentcnergy-is' used to operate the 'hammer, 1t is'desira'hle to'control the operation of the switching device'in accordance with the-op eration of the l1a1nmeri*"lhe switching 'de-" vices may thus be controlled' to operate at optimum instants, that is, at instants beyond which continuedenergization-of the harmmer is not desired, or at-instants of min iinum circuit current, as zero current values when alternating current 'energyi's' used? Inorder to operate a motoi of the reciprocating :type, it *is necessary; to=supply energy'to the motor in the form of impulses. Alternating current energy, which is de- -rivable from the usual commmsial. light and tion 'in order' that driven drum t 'i's' em lo'yedto douse- Y I 'f 'by the contacts. 2- invention is to l-prdvide f shall constitute a My invention has a mrticulari application Applicatio'n filed March 5, 1924.' Serial No. 697,052.

power circuit, is adaptable for energizing a reciprocating motor but requires rectificathe respective current; wares may be supplied to the motor as energy impulses.

Switching devices, Whether of the motor v ype or of the vibrating type,

after'having been once adjusted, will always operate' at the same time, irrespective of ex- 'ternal conditions in the-circuit controlled lV'hen alternating current energy is used,

it is desirable to open the circuit. at instants or zero current in order toreduce't-he arcing between contact members. In the usual rectifier there is considerable arcing between the contact members.- Such condition is aggravated by the varying inductive react- "ance in the motorwindings caused by the movement of the movable core. VVhen the 'corenioves smoothly in synchronism with the applied energy impulses, the arcing between the contacts is at-a minimum," but when the core moves unevenly and leads or lags behind the energy impulsesfthe arcing is cons derably 111creased.- f;

Due'to the variations'ln the impedance of ment of the core, the contacts would open the circuit of the hammer winding-at times when conditions obtaining in the circuit controlled by the contacts.

ItJis an object of my invention to control the operation of the contacts of acurrent controlling device in accordance with and in response to conditions in a circuit controlled -by the contacts.

Specifically, my object is to control the energization of an electromagnet, particularly such as used as a reciprocating mot-or, by electric, magnetic or electromagnetic conditions obtaining in the :elect-romagnet or motor; v

In pi'acticing myinvention I employ a mel-ereenting motor comprising an actuating tiontot the. actuating winding.

In the present application I use an .electromagnet arranged to -,0per{tte as ,a reciproeating ;motor to do uscfugl Qllk as a perveu ssive itool,- suoh as'an electric hammer, 'for drilling, chipping, ,riveting, .etc. A switch- ..ing ,-devvice, in circuit w th .the actuating winding, periodically transmits an energy Himpulse-tohsaid Winding Ill-I161 establishes a reciprocating movement of the core ,member .in synchronism. with .the transmitted Lunpulses. By reguilatingwthe operation of the switehing devioe in accordance-with the electromotiue iforceinduced in .the auxiliary .or

secondary mind;i ng,-the switchingdevice will be controlled in =accordancewith.the operation of. the leleotromagnet-or electric harm- 3o:

mer. Arcing between contacts of the-switching-device wvill thenebyhe considerably .di-

minished iwhene alternating c rrent en rgy is used, and-the switching device .willbe operated atthe pro )er time when dircotcurrent energy is use -F or a beitter. understanding of the invention, referenceniay be had to the accompanying drawings in which? I Fig. 1is'a= c1oss-sectionalview of an .elecbottom views,'in eleyation, of the magnetic *iClIQlll-t members employed 1n the hammer shown in'Fig. 1;

F igs. .5, 6 and 7 are diagrammatic .views of electric circuits for controlling the opera- -tion 'of the hammer in Fig-1 in accordance with my invention; and

Fig. 8 is a graph illustrating the general form of the current impulses transmitted to the hammer.

As illustrated in Figs. 1 and 2, an elec tric hammer 10 comprises a main or actuating winding 11, a core member 12 respon sive thereto and controlled thereby to do useful .Work, and an auxiliary or secondary winding 13 disposed ad acent the main wind-- ing 11 and the core 12,'t-o be influenced in accordance with the energization of the main winding-11 and the movement of the core 12 The hammer further comprises a barrel or guide 14, of non-magnetic material, to retain the core in a predetermined path of movement. A wlura lit ofironlaminations 15 are dispose around the main winding .11 and adjacent .the barrel 1; .to provide a short air gap within which the auxiliary winding ,l3-,isn disposed. A front end plate 16 is disposed on and secured to the front m nd .of the barrel :14: and accommodates a tool bushing 17 which holds a tool 18 in'the path of travel .of the cone 12in its forward i r me 'Arb eki n pla an dmnd :20 integral therewith are secured :to the ,rear end .01 the .banrel 1A: and cooperate (there- .with ,to hold a spring control-led baqkstop or bumper 521- in position in {the .path (of t ave o he core .12 in ,its backwa momem m- An en los g shell r e singfl r-surrounds the elect-romagnet structure 'anqlis held in position 'by the ,front and the-back end plates 16 and 1-9, A trigger switch 23 is disposed in the handle ofttheihammer ,and

tiating'and stopping operation of the harnmer.

As illustrated in Fig. 2, the laminations are disposed .in sets around the barrel let mid extend radially ,thereigrom. Each set of \lanrinzrtions has an air gap between the .ends of the inner laminations l5. AlLo-f the air gaps ,togetlier. cqnsti.tute an annular air gap which is bridged or shunted by the core in its recipmcatingmovement.

Several of the inner laminations of each set anev provided .wvith tips .or tenons 24,415 illustrated in -;F igs.3- .and 4,, ,that fi-t tightly into .openihgsin the-barred 14 and serve. to lock the windings in position.

In Fig. 5 energy for operating the hammer 10 is derived from a source of energy which may he adinect 101" .an alternating current circuit 25 and is supplied to the main winding 11 of the hammer through a switching device :26 and a magnet switch 27. The magnetswitch is controlled by the trigger switch 23 von the hammer.

The switching device 26 comprises aspring 2S, tending normally to hold the switch contacts closed, and a winding 29, operating, when sufiiciently energized, to open the switch contacts. .The winding 29 is connectedto the secondary or auxiliary winding 13 on the hammer and is energized in accordance with the .elect-r-omotive force induced in the secondary winding 13, to oper-ate the switch 26. A condenser 31 and a blow out coil 32 are provided to diminish arcing between the switch Contacts.

lVhen operation of the hammer is desired, the trigger switch 23 is closed. "The magnet switch 27 thereupon closes to connect the .main hammer winding-11 to the circuit'25 1 through the switch 25=and the blowout coil 32. The core 12 is thereupon drawn toward is subject ,to control by the operator i501 inithe force of the spring 28. The main hammer winding is thereupon (lo-energized andthe core 12, by reason of its kinetic energy continues its movement until it strikes the tool 18 or the backstop 21, depending 'upon the direction in which it is travelling. If

the core strikes the tool, useful work is 'done thereby. If the core strikes the backstop, its kinetic energy-is stored in the spring of the backstop and restored to the core on its forward stroke.

After the core passes the air gap, the switch 26 having been opened to disconnect the main hammer winding, the secondary winding 13 of the hammer is tie-energized. The switch 26 is thereupon immediately reclosed by its spring 28 to reconnect the main winding 11 to the circuit. The core is r thereupon again actuated but in the opposite direction -and when it substantially shunts the air between the ends of the laminations, the switch 26 is again opened to disconnect the main winding from the circuit by reason of the electromotive force induced in theauxiliary winding. The core is thus moved back and forth at a frequency depending uponthe frequency of operation of the switching device 26.

The time element of the core and the time element of the switching device 26 should be equal. That is, the time from the instant of maximum voltage in thesecondary winding of the hammer, until the core is out of the air gap, mustbc equal to the time which clapscs between opening and reclosing-of the contacts of the switching device 26.

Such correspondence may be obtained by adjustment of the spring 28 to vary the time element of the switch device.

Reciprocatory motion of the core may thus be obtained by periodically energizing and tie-energizing the primary or main winding of the hammer and utilizing the.

voltage induced in the secondary winding to operate or control a switch or other device for controlling the energization and deenergization of the primaryor main winding.

By reason of the inductive relation of the main and the auxiliary windings of the hammer and the magnetic circuits associated therewith, a transforn'ieraction exists when the main winding is energized. Only a rela-.

tively small electromotive force, however, is induced in the auxiliary winding when the main windingis energized, until the; core approaches the air gap. At that time, more efficient transformer action occurs and the induced electromotive force increases rapidly to a large value,whichissufiicient to operate the switch 26. l

The operation of the hammerconstitutes,

in effect, a series of operations as an electro-:

magnet. After' each operation has -'been effected the circuit of the operating winding is momentarily opened to tie-energize the winding. By means of the electromot-ive force induced 'inthe auxiliary winding, the

'formance'of each operation; that .is,'-the movement of: the core in onedirecti'on-or the other. 'Such -induced electroinotive force may be utilized for a useful purposeto indicate the operation oft-he hammer or to regulate its operation, as is herein described,'by controlling an external current-transmitting device. 1 r

I have disposed the auxiliary winding ad jacent the air gap although it may be disposed in otherpositions inwhichit. will-be influenced by'the magnetic flux developed by the main windingi -In the'airgap the auxiliary-winding appears tobeamost responsive to the fiuxvai iations efiect'ed by thecore-in its movement. c

In Figure 6 a modified i-rcuit is diagrammatically showh-,: similar to't-hat 'in-Fi'g. 5, except that a'switching' rdevice 40, ditferent I in design, is -employed instead 5 of the switch device 26-ofi-tlie system in Fig. 55. 5""

The .switch-dev-ice 40, of-Fig. 6, comprises in addition to the I switch contacts, a holding coil 41,- and an operating coil 42. The holding coil 41 is energized from the circuit and is controlled by the magnet switch 27.

The operation of switch tOis similar to that of switch 26, except that the holding coil 41 restores or closesthe switch contacts after each opening of the switch by the.opcrating coil 42 traversed by current induced in winding l3. .In the system in F ig. 6 the lag or inertia effect of the spring on switch 26, is obviated.

Normally the holding coil 41 maintains the switch contacts closed. \Vhen the core of the hammer approaches. the air gap and the secondary winding 13 of the hammer is energized to its maximum degree, the oper ating coil 42 is energized to open the switch 40 against the pull of coil 41.. The main hammer winding and, consequently, the secondary winding are de-energized. The

holding coil .41 immediately restores the ing and the core is reciprocated in synchrm hammer automatically"indicates the perinismow'ith the im pu'lsese The switch is thus automaticallycontrolled-;to operate at :the proper instant/by the auxiliary hummer winding. Q

Iii-(Fig. -7 {is illustrated another modified systole-embodying mywinvention. In this I system I employ aimeoh'an'ical vibrator 50 as the switching device tomontroilthe circuit of. the. :mmn hammer winding. rllhe -v1bra- -.tor--5O comprises a-swdtc'h member 51, an o perating (c011 52,;a spring 53 and/a regulating coil-54. -i'zlhe. operating coil .52 is controlled udlirectly 'iby the trigger-"switch 23.

, :NVrhen ,the tri gier switch 23 is closed the (0 erat' vcoil 5 us ienex ized'itrom an alter- -cnatingicu-rnent. circuit 55 and together wit h zithe. spring 5,34 effects synchronous viibrwti o n -1olf'theiswitclnmembe1' 51. The switch is thus '.-closedfoi' the duration soif waues of one poilanitxy; and isiqpien for (the duration of waves 50f: 2QPPOSit :polarity. The vibrator thus operates a's 1a 'mec'h'anlical rectifier, t-l'ailliix-mittimg-gaill currentiamaves of one apolzrrity but not waves of opposite polarityu'z-The ipolarityiofz tihe iaransmitted waves will depend upon rthe polazrity of the first were idur ingivhich the switch member 51 is closed aiiter-o'losu're'of the (trigger switdh 23.

"The switchwmember 51 vibrates in synclammIi-sm wirth-the current traversing the operating COll:52,' 8iI)(1Jby adjustment of :the

spring 53 the travel of the switch =meun-ber a5l fma'y be ireducedto ia=minimum.

The switch willliopen and .close at instants corresponding to the. timel when the current va'lue iszero. 1 :Haviing once been adjusted,

the switch 5l will open and close when the value of tlhetcuriient the switch operating coil becomes-zero, irrespective of conditions in-ithe'circuilt of the hammer operating coil.

By reason of the 'varying inductance of -tl1e hammer operating-winding 11, caused 'lbYhhQ movementofthe core 12, the current voltage as the current traversing the switch =-operating winding 52. The-switch 51 \Vlll traversing rthediammer'rwinding' will not have the samephase-relation 'to the circuit therefore open when current traverses the hammer operating winding circuit and arcinget the switch contacts will result.

By means of-the regulating switch coil 54,- however, iheopemtion of the switch may be regulated in accordance'with ouriGO . or substantially zero.

rent conditions in the hammer winding or switch circuit. The operation of the switch may be accelerated or retarded depending upon the movement of the core ofthe. hammer. The switch may thus be controlled to opera-teat optimum current values when the current traversing the switch will be zero The auxiliary winding 13 of the hammer is connected to the regulating coil 54 in such .manuer :that' the regnlatingcoil flux bucks or synol'rronism;

normal speed, the-rectifier switch opening 'or counteracts the flux of the uoperat-ing coil 52 of the vibrator or rectifier.

The auxiliary winding 13 on the hammer is energized in accordance with the movement of the core in the hmnuner. \Vhen the core reaches the midpoint of its stroke, adjacent'the air gap between the \tipsof .the laminations, the auxiliary windingattains its muxiui-um degree o f energization. ;The

regulating coil 540i the rectifier 50 there upon eneng'izedkto --.counteract the holding eflectaoi the ;opemting .=c il ,52. and ;th.e.con-

t acts aredisengaged to opeuthe circuit-of the main hammer winding. Pl. .Hrhe core continues in its-movement, however, until it engages the tool 18 or the springcushioned stop21=upon which it ex-pends the energy stored :therein by the action of the operating coil.

i i I 41! Alternate current waves ure-transmittedto the main hammer winding; by the rectifier to actuate the core member in ithe onel direction or-the 'other', and the-core is permitted to continue its travel after tl iecessation of each current wavezduningwthe intervals beg :twcen such current waves, to' exypendwits kinetic energy upon the tool or the ibackstogp.

' The core is thus rcoipnocated in 'synohronism with the transmittedcurren-t :waves at frequency correspondin oi the circuit current. 4

The oscillogram ini-Fig. zi8-:;il'lust-rates a typical wave form of current transmitted to the hummer-by the rectifier. 2 a r -The auxiliary winding 13:0n hhehammer and the regulating -.w:i:nding 54 of therecti- 'fier operate :to control the reotifier'sw itohel to increase 'or-to diminish the durationof cu-ch "current wave according to whether the core lags or leads itswnormul speed.

core is thus hep-t instep *synchrbnism with the alternating cur rent in the supply circuit, or with the unidirectional pulsations of-curre'nt in the main hammer win'din'g. In case the corelwggor is retarded in its oper-' .ation, the duration of-tl'recurrent wawe is extended to increase the magnetic im pclling force on the core, audit-is brought into step In case. the core 'leads'its is accelerated toj-diminish' the duration of the current wave and reduce the magnetic impelling force, to keep the core in SyHClHO- v to :half the frequency the rectifier isnecessary to reduce the travel of the switch member and consequently, the

arcing. This does not mean that the conditions which cause arcing are eliminated, but merely that the extent of separation of the contacts is limited and that the arcing ocrurs between relatively close contact surfaces. I Under suchconditions, it is ol course impossible to ,cut off the circuit sharply because of the low resistance 01 the short are, and for, that reason considerable energy stored'in the magnetic field of the hammer broadly a methodof controlling the .gnergi is dissipat ed in. the are as heat, with the consequent vdeter-ioration of the contact surfaces. I l

"hea the ,auxiliary"windings are employed, ,however, the rectifier is automati-j windings are used, the' 'arcing between the rectifier cont 5 1s therefore reduced to a. minimum, andt. iredeterioration of the. contact-Si precluded.

My invention, therefore,

com prehends zation of an elcctronn gnet in accordance with its operation, and means responsive to a condition'io'f the electromagnet for con. t1.' o1ling an external switching device. Spe

.,;cific ally, my invention com 'n'ehends' a method of and means'for cont-rolling the open atioirof an electric hammer o'tthe reciprocating motor type by regulating or control ling a current transmitting or translating device in circuit with the hammer, in a'c cordancefwith-tlrepperation of the hammer itself."

Although I have shown several systems for controlling the operation of an electric ha mmer of the reciprocating motor type. modifications may be made therein by the substitution of other current transmitting or lrunglating Flori to control lilo hammer without departing from the spirit and scopeof my invention as set forth in the appended claims.

I claim as my invention-- l. The combination with a source of current and a reciprocating motor energized therefrom comprising a field-producing winding and a magnctizable member actuated thereby with respect to an air gap in the field produced by said winding, of an auxiliary winding inductively related to said first named winding, one of said windings surrounding the other at substantially the region of said air gap, means periodically delivering current from said source to said first named winding. and means controlled by the electro-n iotive-force induced in said auxiliary winding controlling said current-delivering means.

2. The combination with a source of alterternatingj cor-dance with f the positionmember for'iegiilat th'o (toil P, redetQlmifld nating current andanpperating coil, :1 movable member controlled thereby: nd a recti lying device embodyingrelatively movable Contact members for suppl ing tothe oper ating coil predetermined portions of'the 'alternating current, of n eansresponsive to a" condition of the coil ir controllinn the" operation of the rectifyin g'de vrc" i i0 6 viate between e e i ec gmlembcr ther'eofl' .3. The combinatio um ah noting current anope able member controlled th fyingf dev' .jcin bodying' 1 latn Iated to. i ei Qberet the operatieniiof j tlier 4- Te. enema" nating can-mt and H 1. able memb r controlled nda'rect1fiymg deviceogembo'dyi iiiovable contactmeniber' the a ting coil jp rectifying device.

5. Theconibr .o r natmg current eiatmgf coil a mo V1,; i 5' 5 able member cont! l led therebyand a'rectlf mg device ondzt ing' cur'ren iof a inductively related op at I influenced by m oy bleinern b for regulatingthe he rzefcti'f ngfdevicef 'Gl 'Th'e cdmliinati ori wrtli a sotirceo'f alter nating current and a main operating coil, a movable member controlled thereby, a rectifying device embodying relatively movable contact members and an operating coil therefor for supplying to the main operating coil predetermined portions of the alternating current, of a secondary coil inductively associated with the main operating coil, 21 secondary coil inductively associated with the operating coil of the rectifying device, and means connecting both secondary coils in closed circuit relation.

7. The combination with a source of alternating current and an operating coil, a movable member controlled thereby and a rectifying device embodying relatively movable contact members for supplying to the operating coil predetermined portions of thealternating current, and a coil for controlling said contacts, of a secondary coil inductively associated with the main operating coil, and means controlled by the secondary coil for controlling the rectifying device.

8. In a system for operating electric hammers, a source of alternating current, a solenoid, a core reciprocable thereby, a rectifier 1n e e aweuni rom zi di sdure rth "We. aid Wi ding an ux iary! w ndi g n ye ie ted y,

I an, el'ectrq qnoti.

9. The combination with a source of hlterat n rre t. and. a; 'n z e ng. ote mpris g a n ti eldl a mg li eni t ndin r ene i i g th field; an

meme memh i nife el w h. sp t to said I I ir .gapfllength; Qfmeans e fe ting hvery f 'directidngrljmnulses of; current said st named .n p

d. meme ,m .e

9; flfhe' eqmhnw; 1.1]Wit 1,, ,.S 1; 'Q 1 eaming l s ntanfilj 'freciR i e ting motor ri ng emgee ee e lu W V l o e z whe. li lsliien ia ma n i mber mo ed tthereby iof me'zinsiintei' vening b'emp ls s,them hr u msen f i g.

"force ,dfeRendent upon the uu' it n sa d. Wldifigjfildr hg o eme t f. 1:-. megli tie ine e ifi' nd. m nn-Q t l theimnt se. po is t aid-i l trb,

mo' y rr eme- '5 ,i

e' h e ing q g rent ndia Q e i e r said current impulses.

@slaid winding in r e'- said magnetic member, and means c0ntrol-' ling the rectificetion'in' response to said electro motive forcel 12. The combination with a source of current and 1a reciprocating"motor, comprising a'niagnetie field having anhir gep, a Windineiiiher niovable respect to said air gzip tojibsition, beyond I'minifnum' air gap cessiye impulses of currentfrom said source thro gh;SitldiW1i1d1ng,"a hux liary winding located said 51 r ','iriductively affected said gfiis' named and sziid magnetic m jfln's' \v lth s'ai d h ux llia ry w nding I circuit controlling .T 3- iii. cem ii fii n {w ed me ternjatliig current and I h reci rocating motor, a field winding for sald motor 'anda magnet- I I II I izable member moved thereby ofi inductive we alute-end $e1d= mada f mg. delivery of preponderatmgly uni-g irect onzrl men ns connected saiid source ivhil'e' saidmotor is in operat on for controlling-the transmiss on OfIliIiIdIIG QbmhflI current impulses iliery', winding; m uet it ely reliiftechto said field windingiand Ia clhpt ed. to react upon .said an clthei-ehy'modi'fjrtl1e,du-

r t-said if .'I have hereunto s mdn'y he-resubscribed lmy this; "day of Febaiy, 92f EnWA-RDir:

MZISS-IEN;

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