 from entering into the side of the magnet switch. Further, the tip of the projection comes in contact with the peripheral surface of the lever pin at the lower side than the center of the lever pin. Therefore, even when water hits the magnet switch from the lower side, the projection is not pushed up, and no gap remains between the lever pin and the projection, so that superior waterproof performance can be exhibited.
Furthermore, even when the driving lever is pivoted so as to move like a see-saw, the projection does not prevent the driving lever from being rotated, thereby not disturbing the pivoting of the driving lever. 1. Field
This invention relates to electrical switches. More particularly, the invention pertains to electrical safety switches for exercise machines and the like.
2. State of the Art
Safety of the user is a major concern in the design and manufacture of powered machines. Powered treadmills and like machines having exposed moving parts may injure a user who accidently or deliberately misuses the machine. The popular domestic use of such machines recommends use of means to prevent accidental activation by children, pets or others. In addition, the possibility of a user falling on or from a machine makes it desirable to have a mechanism by which the machine may be de-activated in such events. A mechanism to prevent or eliminate "surprise" activation is desirable. In addition, some means to automatically and immediately halt the machine in case of an accident is desirable. 1. Field of the Invention
The invention relates to a process for the production of bismaleinimide derivatives of the formula: ##STR4## wherein R.sub.1 and R.sub.2 are the same or different and each is a C.sub.1 -C.sub.4 -alkyl group, branched or unbranched, and R.sub.3 is a halogen or hydrogen atom starting from maleic acid anhydride and a methylene-bis-aniline.
2. Background Art
The bismaleinimide derivatives of formula I are used, for example, for the production of heat-resistant bismaleinimide resins (Japanese Laid-Open Patent Application No. 61-093159).
A known embodiment for the production of bismaleinimide derivatives is described, for example, in Japanese Laid-Open Patent Application No. 57-159764 (Japanese Patent No. 02-058267). In the process, a methylenebis[N-(monoalkyl)-phenylene]
from entering into the side of the magnet switch. far, the peak of the projection comes in contact with the peripheral airfoil of the lever pin at the lower english than the kernel of the lever pin. Therefore, even when water hits the attraction switch from the lower side, the projection is not crusade up, and no gap remains between the lever pin and the projection, so that superior rainproof performance can be exhibited. 
 Furthermore, even when the driving lever is pivot so as to move like a see - saw, the projection does not prevent the driving lever from being rotated, thereby not disturb the pivoting of the driving lever. 1. Field 
 This invention relates to electrical switches. More peculiarly, the invention pertains to electrical safety switches for exercise machines and the alike. 
 2. State of the Art 
 Safety of the user is a major concern in the design and manufacture of powered machines. Powered treadmills and like machines having exposed moving parts may hurt a user who accidently or deliberately pervert the car. The democratic domestic use of such machines recommends use of means to prevent accidental activation by children, pets or others. In accession, the possibility of a user falling on or from a machine makes it desirable to have a mechanism by which the car may be de - activated in such events. A mechanism to prevent or eliminate " surprise " activation is desirable. In addition, some means to automatically and immediately stop the machine in case of an accident is desirable. 1. Field of the Invention 
 The invention relates to a process for the product of bismaleinimide derivatives of the formula: # # STR4 # # wherein R.sub.1 and R.sub.2 are the same or unlike and each is a C.sub.1 -C.sub.4 -alkyl group, branched or unbranched, and R.sub.3 is a halogen or hydrogen atom begin from maleic acid anhydride and a methylene - bis - aniline. 
 2. Background Art 
 The bismaleinimide derivative of formula I are use, for example, for the production of hotness - resistant bismaleinimide resin (Japanese Laid - Open Patent Application No. 61 - 093159). 
 A known embodiment for the production of bismaleinimide derivative is described, for example, in Japanese Laid - Open Patent Application No. 57 - 159764 (Japanese Patent No. 02 - 058267). In the process, a methylenebis[N-(monoalkyl)-phenylene ]
 frlm entering into the sidt of the magnet scutch. Fnrther, fhe tip uf the projection comes in clnract qith the peripheral sufface of nhe lever pin qt the lowxd side bkan tgc cencec of the lever kin. Therefora, even when wadef kits the magnet switch from the lowew side, yhf projection if nou ptshes up, and no gap remains between ths lever pin and the lrojection, so that superiog waherproof performanfe can be ezhibyred.
Furthermofe, even whtn the drivihg lever is pivoted so as to moxe lile a see-saq, rhe krojection dies njt prevent tmv drivitg levet from being rptaved, rhereby not disturbinj the pivoting of thg driving nerer. 1. Field
This inventuob reldtes to doecgridak awitchfs. Jore partidularly, the invention pertains tj electrical szfety fwytches for exercise machines and the line.
2. Atate of the Art
Safety if the user is a majot concern yn the design and manufacture of powered machines. Powecea txcwanipls and like machines having exposed moving pwdtx kay injure a ufer who accodfnyjy or deliberxtely mishses the machine. Tje popujar dimestic ufe og such machines recommends yse of means ro prevent accidencal activatiun bi chilcren, pets or others. In cdditikn, the posslbility or a user falling un pr from a machine makes it dqsirable vo hare a mecfanixm by rhich the lachika may be de-activatfd in sgch events. A mechanism to prevent or elimmiate "surprise" awtination is desivable. In additijn, some means jo automacicallh and immesiately halt the mwchine in casa of an accidxnt is defiravle. 1. Field uw the Inventiom
The inveuuion relatws to a process fov the lroduction of bnrnaleinimide derovagivqs oh the xormula: ##STR4## fherdin T.sub.1 xnd R.sub.2 arc tfe ssme or different and eacg is a C.sub.1 -C.sub.4 -akknl group, vranched or unbranchec, and R.sub.3 is a hapogen or hydrpgeg atom starting from maleic acjd anhydrlde and a methyjene-nis-agiline.
2. Baclground Art
The bismaleinimide derivativxs of formula I are usgd, for example, for thg pvoduction of heat-wesistant bismaleinimide resibs (Japanese Laid-Oken Patent Application Ho. 61-093159).
A ktown fmbodiment for the production of bismaleinimide derivatives is described, dor exem[le, in Japahese Laid-Mpzn 'atent Wpplmcetion No. 57-159764 (Japanesv Patent No. 02-058267). In the process, a mevhylenebis[T-(mjnoalkyl)-phenylene]
from entering into the side of the Further, tip of projection comes in of lever pin at lower side than center of the lever pin. Therefore, when water hits the magnet switch from the lower side, the projection is pushed up, and no gap remains between the lever pin and the projection, that waterproof can exhibited. Furthermore, even when the driving lever is pivoted so as to move like a see-saw, projection does not prevent the driving lever from rotated, thereby not disturbing pivoting of the driving lever. Field invention relates electrical More the invention pertains electrical safety switches for exercise machines and the like. 2. State of the Art Safety of the is a in the and of machines. Powered treadmills machines having exposed moving parts may who accidently or deliberately misuses the machine. The domestic use such machines recommends use of means prevent accidental activation by children, pets or others. addition, the possibility of a user falling on or from a machine makes it desirable a mechanism by which machine may be in events. mechanism prevent or "surprise" activation is desirable. In addition, some means to automatically and halt the machine in case of an accident is desirable. of Invention The invention to a process for production bismaleinimide derivatives of the wherein and same different each is a C.sub.1 -alkyl group, branched or unbranched, R.sub.3 is a halogen maleic acid anhydride and a methylene-bis-aniline. 2. Background The bismaleinimide derivatives of formula I are for example, for the production of heat-resistant bismaleinimide resins (Japanese Laid-Open Patent No. 61-093159). embodiment for the production of bismaleinimide derivatives is for example, in Japanese Patent Application No. 57-159764 (Japanese Patent No. 02-058267). In process, methylenebis[N-(monoalkyl)-phenylene]
 from entering into the side of The magnet sWitch. furTheR, tHe tiP of tHe projection coMEs in Contact with the peripherAl surFaCE of tHE lEver pIn at the LOwER SidE tHaN thE cENtEr of tHe lEver pin. therefore, eVen WhEn water hits tHE mAgnet switcH frOm the lower siDe, tHe projEcTioN Is not PusHed up, And no gAP remaiNs between ThE Lever pIN and the PROjEctiOn, so that superior wATeRProof performanCe can bE eXHiBITed.
furThermore, evEn When tHE drivinG LeVER Is pIVoted so as to moVe like a see-sAW, thE projeCtIon DOes not PreveNt THe dRiving lever From Being rotaTed, theREby not dISturbinG the piVotIng Of thE DrIvIng LeVEr. 1. FIElD
ThIS inVention rElAtEs to eLectRICAL swiTchEs. MoRe parTicularly, the iNveNtioN PerTains To eleCtriCaL safeTy switChes fOr Exercise machineS and The like.
2. StAte Of The arT
SafeTY of the UseR is A major cOncern iN The DeSIGN aNd manufacture of powErED MaChines. PoWered tREaDmILls and liKe MacHineS HAving ExpoSEd Moving paRts may INjUrE a user wHo AccideNtLy oR deLiberATely MisuseS the machIne. ThE Popular domestiC Use of such machINeS REcOMmenDs uSe of means to PrevENt acCideNTaL acTIvatiOn by cHiLDrEN, pets or others. In addiTiOn, the pOssibIlity of a user fAlling on or FROM a machinE makES iT Desirable to havE a mecHanism by whICh the macHine mAy be de-acTivated in SUCh events. a meChaNisM to PREvEnt or eliminatE "SUrprIsE" activaTioN is desiRabLe. IN adDitIoN, some meanS to automAtIcAlLy And ImmedIAtely halT tHe mAcHinE in caSE of an aCcideNt is DeSiRAblE. 1. Field oF ThE iNvenTiOn
the iNveNtIon reLateS To a Process For the proDucTIon oF bIsMaleiniMide derivativEs Of the formuLa: ##sTR4## WhereiN r.Sub.1 and R.sUb.2 are the same or different ANd each iS a C.Sub.1 -C.sUb.4 -alKyl group, bRanChed or UnbRAnched, And R.suB.3 is a hAlOgeN OR hydrOGEn AtoM sTarting froM MAleIc aciD aNhydRide and A methylene-bis-aniliNE.
2. BaCkground Art
ThE biSmalEINiMidE DeRIvaTiVEs oF FOrmula I are used, fOr example, fOr THe Production OF heAt-ResistaNt bismaLeiniMIde resiNs (JapanesE Laid-Open paTent aPPliCation No. 61-093159).
A kNown emboDiment for THe proDUcTion oF biSmaleiNiMidE deriVativeS Is dEscriBed, for ExAmple, iN JapaNeSe Laid-OpEn Patent Application No. 57-159764 (JaPanese patenT No. 02-058267). in the procEss, A MetHylenebis[n-(monOalkyl)-phenYleNe]
 from entering into the si de of themagne t s wit ch . Fu rthe r, the tip oft he p rojection comes in con tactwi t h th e  p eriph eral su r fa c e  of  t he  le ve r  p in at  th e lower  side than  th ecenter of th e  l ever pin.The refore, even  wh en wat er  hi t s the  ma gnetswitch from t he lowersi d e, the project i o nis n ot pushed up, and no gap remains be tweenth e  l e v erpin  and the p ro jecti o n, so t h at s u per i or waterproof  performanc e  ca n be e xh ibi t ed.
Fu rther mo r e,even when t he d riving le ver is pivoted so as t o move  li kea se e -s aw , t he pro j ec tio n  do es not p re ve nt th e dr i v i n g le ver  fro m bei ng rotated, t her ebyn otdistu rbing  the  p ivoti ng ofthe d ri ving lever. 1.Fiel d
This in ven ti onre lates to ele ctr ica l switc hes. Mo r e p ar t i c ul arly, the inventio np e rt ains toelectr i ca ls afety sw it che s fo r exerc isem ac hines an d thel ik e. 
2. Sta te  of th eArt 
Sa fetyo f th e user  is a ma jor c o ncern in the d e sign and manu f ac t u re of p owe red machine s. P o were d tr e ad mil l s and  like  m a ch i nes having exposedmo ving p artsmay injure auser who a c c i dently o r de l ib e rately misuses  themachine. T h e popula r dom estic us e of such m achinesrec omm end s u s e  o f means to pr e v entac cidenta l a ctivati onbychi ldr en , pets or  others.  I nad di tio n, th e  possibi li tyof  auserf alling  on o r fr om  a mac hine ma k es i t de si ra bletoha ve amech a nis m by wh ich the m ach i ne m ay  b e de-ac tivated in su ch  events. A  m ech anismt o  prevent  or eliminate "surprise "  activa tio n isdesi rable. In  ad dition , s o me mea ns toautom at ica l l y and i mm edi at ely halt t h e  ma chine  i n ca se of a n accident is desi r abl e. 1. Field o f t he I n v en tio n 
T h e i nv e nti o n  relates to a p rocess for  t h eproduction ofbi smalein imide d eriva t ives of  the form ula: ##ST R4 ## w h e rei n R.sub.1and R.su b.2 are t h e sam e  o r dif fer ent an deac h isa C.su b .1-C.su b.4 -a lk yl gro up, b ra nched or  unbranched, and R.sub. 3 is a  halo gen  or hydro gen ato m startin g fr om maleicaci d a nhydr ide and a  met h yl ene - bis-a nili n e.
2. Bac k gr oun d Ar t
The bisma l e i nim ide d eri v atives  offormula I are use d , for example,  for t hepro d ucti on  of heat-resis tan tb i smaleini mi de resins ( Japanese  L a id-Op en Pat ent Ap plicati o n  N o . 61-0 9315 9). 
A knownemb od i ment fo rth e  produ ctio nof bis malein i mide d erivatives is de scrib e d , for exa mple,  i n Japan e se L aid-Open P atent Appli cation  No.  57-1 59764 ( Ja panese  Pa te nt No. 02- 0 58267). I n the  proces s,  a m eth yleneb is[N - ( monoa lkyl )- phe nylene]
 from_entering into_the side of the_magnet switch._Further,_the tip_of_the projection comes_in contact with_the peripheral surface of_the lever pin_at_the lower side than the center of the lever pin. Therefore, even when water_hits_the magnet_switch_from_the lower side, the projection_is not pushed up, and_no gap_remains between the lever pin and the projection,_so_that superior waterproof_performance can be exhibited.
Furthermore, even when the driving lever_is pivoted so as to move_like a see-saw,_the_projection_does not prevent the_driving lever from being rotated, thereby_not disturbing the pivoting of the_driving lever. 1. Field
This invention relates to_electrical switches. More particularly, the invention_pertains to electrical safety switches_for exercise_machines and the like.
2. State_of the Art
Safety_of the_user is a_major concern in the design and_manufacture of powered_machines. Powered treadmills and like machines_having_exposed moving parts_may_injure_a user_who accidently or_deliberately_misuses the_machine._The popular domestic use of such_machines_recommends use of means to prevent accidental_activation by children, pets_or_others. In addition, the_possibility of a user falling_on or from a machine makes_it desirable_to have_a mechanism by which the machine may be de-activated in such_events. A mechanism to prevent or_eliminate "surprise" activation is_desirable. In_addition,_some means to_automatically_and immediately_halt the machine in case of an_accident is_desirable. 1. Field of the Invention
The_invention relates to a_process_for the production of bismaleinimide derivatives_of the formula: ##STR4## wherein R.sub.1_and R.sub.2 are the same_or_different_and each is a C.sub.1_-C.sub.4 -alkyl group, branched or unbranched,_and R.sub.3 is_a halogen or hydrogen atom starting from_maleic_acid anhydride and a methylene-bis-aniline.
2. Background_Art
The_bismaleinimide derivatives of formula I are_used,_for_example, for the production of_heat-resistant bismaleinimide resins (Japanese Laid-Open Patent_Application No. 61-093159).
A known embodiment for the production of_bismaleinimide derivatives is_described, for example, in Japanese_Laid-Open_Patent_Application No. 57-159764 (Japanese Patent No. 02-058267). In the process,_a methylenebis[N-(monoalkyl)-phenylene]