вход по аккаунту


Патент USA US2137812

код для вставки
Nov. 22, 1938.
Filed May l, 1933
5 .Sheets-Sheet 1
Nea/Z072 ¿Sc/zelleçaer.
ßfz/#my JLÜMW..
»> ,6è/¿gui
Nov. 22, 1938.
Filed May 1, 1953
3 Sheets-Sheet 2
` Newton, âßa/zelleîßaer.
E? W "5“ 7,4%;î'
Filed May 1, 195s
„_ 20a
:s sheets-sheet s
FIV' ‘75'
i? f4'
[7n/@n 2607":
Newton á’. Saiz e Z Z @72 er
- `Newton C.' Schellengier, Elkhart, Ind.-,-’a'ss'ignor‘to
î-Chicago Telephone' Supply Company, a corpo
Annamaria; ¿_1, 1933, serial.
. 1o claims.
lMyinvention- relates tocontr'ol devices for elec
@63u51 _
(c1. zal-4s) »
tenings, as well as portions lying beyond'the fas
trical circuits. and,- more particularlmto variable tenings, .which,__of course, means a sacrifice of
resistance devices o_f the4 general typesetiorth
in my prîorPatent No. `1',85`1,933,.granted Mareh
effective resistance.
Otherway's, equally as troublesome, have been
tried .without success. One of these contemplated 5
` The present application is directed towardim
countersinking, a, cylindriçally-headed rivet in a
proving _variable resistance .devices of ,the fin Y complementary aperture in thelbase, to permit the
` termediate contactdisk type, and especially those passage of the v,contactor member thereof., It was
that are exceedinglysmall and Ac<'_)mp_act._._ „ ,_ _
Heretofore,..in_- the 'types . of devices v.c_:haraçter
found,_ however, _to .be >impossible to obtain a
Asmooth` eonnectionsurface between _the _rivet and l10
' ized . above. fit'. has ,been"'inìpossible to obtain' `,a the resistanceasince either the-_Iivetheadwould
jclear,4 lsharp.,fxvve1lf defined line .of »contact between
Project meeneem-the .contacter-.prematurely to
‘ the contacting` diskfand- the resistance.A element. ,short-circuit,someeffective resistance, or .else _it
_has _been particularly v_true InÄdeViceS'of-this _would fail „toftouch _at` all, .(being, countersunk
.15` type .wherein ¿the . diameter. or width. of .s'u'ch'de
vices >ïis'ÍfqliiteÍ'snjiall; Qi. e., not'infexc'ess ofÍ-.thïree
too _great..a,_depth), wherebya high minimum re
sistance;y value_resulted. at lthe _ low „resistance ter
_ inches..`_
_Thisfcondition has. beenQdueto
. .
.,.¿', the `_fastei'iing
_ »
In combination variable resistance and power
means. employed .between `the . contact ',Ídisks @or l switch units_,_,wherein_ both devices vare controlled
,20, rimsa?d their central' hubs;~ 'These fastenings .by a singleactuating shaft, there has heretofore
usually .'wer'e straight,l radial spokes', ,which- .were
been a furtherì sacrifice of. effective _ resistance.
necessarily short toconform with _the >require The__switch mechanism was caused to be actuated
ments of the small mountings and casings within , overfa portion of resistance elementadjacent the
which they were assembled.
` .
low resistance end, .which means that the switch
In the radial spoke type’of intermediate disk, 'was caused to open the circuit 4before maximum
_low resistance position couldbereached by the
contactor; and, conversely, when the contactor
their length. These increments of bent portions was moved from the extreme low resistance posi
when the rim is depressed intermediate any two
of the spokes, the spokes bend _at portions along
lie within, or parallel to, chords of a circle lying
30 within the rim, and to whichchords-the longi
tudinal axis of the depressor arm isv always sub
stantially normal. This action ‘causes the entire
segment of rim subtended by the major chord to
be depressed downwardlytoward the resistance
" element, and a considerable amount of .the entire
_depressed segment actually engages the resistance
element. Thus, if a substantially planar re
sistance element is employed, _a fine', well defined
line of contact cannot be effected, and a sensitive
40 variation in resistance values is rendered impossi
' Another diillculty in the prior art has been en
countered in the connecting of flat, carbonaceous
resistance elements to terminals by means of riv
45 ets, screws, etc. It is necessary that some such
fastenings be utilized to effect contact between
the resistance element and the terminals at the
‘ high and low resistance ends of the element. This
has been done heretofore by appropriating the ex
tremeend portions of the resistance element to
fasten, by means of large headed rivets that pro
ject above the contact surface.l the lresistance
element and terminals to the base. This type of
assembly necessitates the forfeiture of that por
55 tion of the resistance element underlying the fas
tion, a substantial amount of the resistance ele
ment was traversed before the switch was ac
tuated to close the circuit. Thus, a considerable
amount of otherwise effective resistance was ren
dered totally unusable.
Covers or housings for devices of the char
acter described, and particularly those covers 35
adapted to carry power switches, have been the
source of much consternation and worry in the
First, it was necessary to provide proper spac
ing means between the cover and the variable re 40
sistance device, to insure that parts of the switch
and resistance device were in proper cooperative
Secondly, there had to be provided
means to retain the cover in positive engagement
with the variable resistance device to insure 45
against any relative. movement therebetween.
Thirdly, to position the cover, provision had to be
made for terminals and other projections ex
tending from the variable resistance device.
These necessitated the provision of apertures, 50
which permitted dust, dirt and other foreign mat
ter to find its way into the casing to the detriment
of the sensitive’parts therein contained.
Therefore, it is an object of my invention to
provide a variable resistance device of the inter
posed contacting disk type wherein contact of the
ance element arcuately disposed may readily be
disk with the resistance element approaches a
linear tangency as a limit.
A sleeve or journal bushing C extends through
an opening I2 in the base. The bushing C may
serve as a mounting device for the unit, by being
threaded at one end I4 for the reception of a
It is another object of my invention to provide a
5 contacting disk for variable resistance devices of
the interposed contacting disk type, that is high
ly flexible and which is capable of having periph
eral portionsgdistorted _out of their-_normal plane
without distúrbingftheposition`of its other por
10 tions._
nut by which the assembly is clamped upon a
ïsuitable bracket.-~
.Theil bushing C contains an enlarged head I6
disposed against the surface of the base upon 10
It .is’still another object of my invention to pro- z which the resistance element is located, and if de
sired this head I6 may be serrated or knurled as
resistance device, which has novel means for en- ' shownat I8, 'see Fig. 3, so that it will bite into
vide a durable, inexpensive cover _fora vvvariable
gaging the base of such device Éfor retention there-_. _the basato prevent any relative rotary movement
- ,between-thebase and bushing.
15 0D.
ff 'r 'uw' to- pro
-~ -1
A shoulder 20 of the bushing protrudes through
It is a further object of y invention
vide novel means for spacingl portions of a cover, the base opening and also through a holding
from portions of a variable resistance'device in clampv H and thefree end of the shoulder is ex
predetermined relation, and to render said cover panded to grip one face of the clamp for the pre
20 dust-proof.
' It is still'a further Object of my invention 'to
`provide for fastening‘a -flat carbï>naceous> resis
tance element to a base member‘by'means lying
vention oi' longitudinal motion _and to grip a, plu
rality of spaced ‘niches 2_2 of theclfa'rnp‘for the
prevention of - rotary motion. "_Anannular shoul
I_der_24disposed interiorly from vthe enlarged head
‘ within the path of the contactor of'a variable re
I6 constrains an insulating washer'D 'upon which
‘25 sistanc'e device "withoutA affecting the predeter
an interposed low resistance flat contact‘disk E
mined'reslstanc'e gradienfof the element. _ ~
The meiske is preferably _.còmrárisèd'ofa .rim
"'switch ‘unit wherein thelswitch 'is actuated when _plurality offlexible s'erpentinetlspokesjßû. ‘_,ÍI‘he
‘~` It is still a further object of my invention to pro
i vide a combined variable resistance ‘andfpower
26'. anda hub’portion 28 which are'co'nnectedby a
spokes are “substantially Aof >uniforml width from '
f'por'tion‘f'of the‘effective:resistance.ïr
' `With thë‘above andïfelated 7objeicts‘i'n view, my
_inventionëonsist's' in_thèjfollowing details'of con
struction Vand""combinationof’paì‘ts;as will be
"35" 'more' fullyÜunderstoo'd from the'following speci
` ñ'c‘atiorr, "when 'r'ead - in7 conjunction Íwith the‘iac
companying drawings, in which:
Figure' 1A is' va. perspective view of `la lvariable re
-'sistance device-'constructed in `accordance >with
:940 my invention. illustrated'with th'e'cov'er remQVed;
-' ' Figure 2'is`-'a to‘p'plan view of Figure 1; `
Figure '3 is amid-sectional view of the variable
resistance device and' 'cover having a switch
l'mounted thereon ; 'the switch not being'shown in
45 section;
Figure '4 Ais an‘exploded vperspective view of the
' variable' resistance device _and coverillustrating
the relation of parts and order of assembly;
Figure’ö is a' top plan view of‘a modified form
50 of a pressure- arm;
Figure '6 is a sectional view taken on the line
6-6'of Figure 5;
Figure 7 is a plan view of the pad holding blank;
Figure 8 is a side view of the modified pad
55 holder;
Figure 9 is a fragmentary exploded sectional
view of a holding structure at each end of the
resistance element;
Figure 10 is a fragmentaif assembled View of
60 the elements shown in Figure 11;
Figure 11 isy a` bottom plan view of the as
sembly shown ‘in Figure 10, more y_clearly showing
Figure 12 is a modified form of pad holding
65 blank; '
Figure "13 is a side elevational view of the modi
fied pad holder made fromthe blank shown in
Figure 12; andv
rounding area. A plurality 'of positionin'g'j'ears l34
are‘jalso formed on the h_ubîby a punchïpr'ess-op- .
eration,'an`d the ears tightly’grasp'notche‘s _36in
Figure 14 is a _bottom plan View of the modified
T0 pad holder shown in Figure _13;
dialm‘ovementjof the disk.
` -‘The 'ï spokes ‘are highly `flexible y and _yieldable,
and due to their serpentine configuration', are
almost twice as long as they would b‘e were they 45
disposed alongv yradii of the diskthroughout their
entire length. Thel increased length fof serpen
tine spokes over radial spokes increases the effec
tive flexibility of the spokes'. The rim supported
by them, being held by such highly flexible media, 50
is permitted far -greater freedom~ of'movement
The advantages of this increasedflexibility may
better be _seen by comparing these types of de
vices with those of the prior art. A rheostat of 55
small diameter, having an interposed eontactor
disc of the radial spoke type, will upon actuation
of the contacter arm, short circuit a considerable
amount of the effective resistance. The short,
stiff spokes tend to hold the rim rigidly between 60
them, whereupon, when the rim is depressed in
one portion, a substantial segment of the rim is
caused to follow the depressed portion to en
gage the resistance element‘for a considerable 65
distance adjacent the contactor arm. Thus, a
sharp or delicate line of contact is made-impos
sible, and‘a considerable amount ofthe effective '
resistance is short-circuited.
The serpentine spokes, however, permit _the 70
Referring in detail to the drawings: An insulat
ing base A, generally circular in formation, has
rim to be rather abruptly distorted out' o'f its
normal pla-ne at the point 1of _contact, without dis
mounted upon one face I0, near its periphery, a
turbing to anyrnaterial extent lthe'planar dis
position of its`A remaining portion. In` this man
'circularly disposed resistance element B of the
'75 lcarbonaceous type, although a wire wound resist
a'positioning 4insi'ilating washer F, to'prevent ra
than has heretofore ever been possible.
the peened'over holding bolt;
cumference." An electrical icox'rductór-"tab‘äZ is
formed upon thahub by Cuttiegßwëy, tha-Sur
ner, a fairly sharp line of contact'is obtained, and 75
the shortfcircuiting of eiïective resistance is min , cylindrical side, walls _a „distance substantially
` equivalent to the thickness ofthe base member
„ y
The disk E and the washer F are secured in _A. Since the housing lis -‘ofsuch size and con
placeby turning overt or peening the end »35 _ñguratiònf as tol snugly Atelescope upon the base
v-of the bushing against the washer
If desired, _.memberfA, _the vliner-"K, being disposed around
._ a metalwasher may be placed over,the washer F
_ to prevent breakage of the washer F provided _it
is- made ofzfragile materîah
l . _
¿the inner side wallslof the housing, diminishes
_theinsidediameterrthereof _to such- a degree
_ thaty _it is` f less.~ than -themean diameter, 0fv the
A pressureor wiper armG, ofthe general type ¿» ba__se__A; Lhence', _the vhousing _is ,unable lto telescope
Áshown in my- application-„flledLJanuary _31, 1930, over thel baseâbe'yondA thel strip’sedge.
Serial No..424,775,.which1has.matured into Pat
_ent No. 1,913,686,.may conveniently consist, of-a
_ >central «_ portion =38 ~secured , to the end -lof, a; shaft
:the[li`ne_r__._> Vfornf'sra: bearing ,shoulder which abuts
_the-base.. member-„_.adjacerít .theedge of its' inner
39 as by'heading overthe splined-_end- ,of-...the .-.face_,..Í and _ since . `its upper'. ._ edgß, ,abuts the >inner
.15 shaft. ~ A- _crescent-shaped arm _4tl- has « its i ends
-i’aceo‘f the _endfwallpf the. housing', it'servesas, 15
yconnected to?‘thel central «portion» Aby ',the, bight .a spacer ,tomaiìi‘tain thelh'òusingbaseland asso
.portion _42. A«Atongue ì44,~;carrying a -pressure >pad _ciatedparts in predetermined spacedffrelation. .
.-48 and projecting from the-.crescent arm 40,-'.is „¿._ _When y,the cover, is 'placedfonlghel basaso Athat
‘ adaptedtostrike radially projecting; _ears -46 of _ notch ¿.'l4.»,`regis_te`r_'s¿withthe 7terminal".mounting
20 the cup-shaped housing or_ covering -J,- inorder _to ¿ extension lof, the base, the"insulating`~1iner l_strip
_ K_,being ofthe sameîbreadth throughout, closely
limit the rotation-.of the arm-` _
The-pressure padmay fbe secure to y-theunder engagesthe basefmember around its periphery,
side of the arm andmayfhowever,> take avariety „angl „closes ,theÍnOtch {1_4. `which.'’over-lies the
of forms. _In the form shown.-ìn¢Fig.<4,.gthe„pad
is formed of a cylindricalâblock- of material, such _ The. IlinerVbein'g Aof flexible material, closely
. as .-oilA impregnated „- leather, .. andv :is >, held; in an
. inverted-eupin any-desiredimanner'.
In Figure-5, another_«modification of-,the pres
sure.> arm;v and-@the
__50 and
52._.are,c'ut into
; -thef ‘crescentfshapedzarmß 40, „and ~ a> :metal istrip
âìisformed .to ¿have one- end'. 58 of iur-'shaped
¿ adheres `to__allpitrtitíns ofthebase, and adjusts
_._itself >toall .irregularities thereofßorender the
The ears 12 arethenl e
the base whereby a coin pact,
over ,toïengvage
rigid and dust-__
proof unit is prôylde'dlïï‘» f` -
fff-:The-.advantageaotfftlieiear .12.- iSt manifest in
assemb1ineffthe-'~unit ruhen ...liner strip «1S em
press» .that-¿crimes »the ears finto
„engagement Awith _th base-_first_¿forces ,thefbase
f through the lopening 5_0, «The tongues» IStand 64,
'-into,iñrmfeneagenientimith 'the adecco!- .linerKá
Wings BE'a'rïdîîG’B, see Figs. 7_,_an_d Spare. formed
far; , superior product
@ersteren tn_.rmeintain the
. p?otrusling :radially ¿familles periphery òf. "the ,rand-then.@umts-¿the
`Acrescent-_shaped - arrn _. _54, t push.. the. j pad, ,around ¿partein;thisrñmfiengagement- fSinœ. this isßll
transversely of one end of the' strip 5€_Ítoiirmly n=f., if meanafiand.
grasp Vthe pressure_.,pad„6_û_._
,_ _
` r`The v housingJ ¿has -aninsulated. strip liner _K
disposed upon the inner peripheral surfa'ce`,__to
45 'providefa substantially dust-_proof vhc'íusin'g,v _to
1» Althoughftheresistance
.base is . annu
lar in formation, the effectiveconducting surface
_ of the _resistance _v-ele_xrientzial arcuatee v_in forma-_
guard any “live” pa`rts'from` coming into contact -. small
tion,l leaving.
a _small-'arc ineffective.
with the lhousing or -s_hell, and to cover _the gap
or .space between the housing _and the terminals. .the transient movement ofthe pressure arm dur
lA plurality ofuslots 70 ~in the liner K have the'jst'op ingtheçclosing-of ,the switch. - Heretofore, com
,~_bined-_swit_ches and» variable resistance `devices
50 members 46'of thehousing'oómpletely pass‘there
l through and Aoccupy the space deñned therein. have_»,been s_o constructed that the switch was
The housing J; within which the" rheostat is actuated over an .effective portion of the resist
' housed, is providedf'witlil a v'pluralityof projecting
ance. ‘ Thus when. the contactor armwas moved
tongues 12' ofy suiii'cientjlength‘ to 'be bent over 'from its point of lowest- resistance, Athe switch
moved toelosed position, but not before the con
55 to attach the housing to the plate A.v4 A_n elon
armhad _traversed a substantial amount oi
gated n'otch14 is out lin the free end of the cy
lindrical 'wall of the housing.' The base-A has an »the effective resistance.. Lîkewisawhen it was
' arcuate peripheral extension 16 through which .desired tofmove the Ycontactor armvto its ex
_ treme low resistancepositionßhe switch would
suitable terminals pass -and Íthe peripheralV ex
be >actuated-,intol open vposition to break .the cir 60
60 tension is constructed to interñt with the »notch » ycuit before this_.couldbe effected. -f Consequently,
"74 of the housing. -The' registration of the ex
a substantial amount .of the effective resistance
tension of the base and the notch 14‘ in the hous
rendered useless. In my present structure,
ing .with the plate A accurately'aligns the cover
with respect to the'plateboth in a rotary direc
this _fault is entirely overcome.
tion about the axis ofrtheshaft and in a direc
the _resistance element base lies _substantiallyin
along the shaft.
The elongated notch 'I4y of the housing J pro
vides some clearance 'over the terminals- to pre
vent any short circuit and the clearance is filled
by the insulated strip liner K.
A vItis essential‘that theentire upper surface of 65
the same plane, otherwise the> rim of the low re
_sistanqe'mte‘rposiëd~uisk will be bent and a kink
` permanently¿._established therein,__ _
- . The baseportionisprovicled with apertures 18` 70
. -and_8_0 _which areîofîsuchsizeas to receive rivets
The liner `K,.is~of .such breadth that it will ex
tend from the end wall portionof thefhousing J, ~ 82 .and 84. Theiedges of the apertures adjacent
down the innerface of lthe side vwalls -thereof to the inner face of lthe base are beveledto form
a peripheral line near end. T_his pe
ripheral line Ais spaced from the free edge of the
tapering .counter-sunk portions.- The resistance
element having rivet apertures .of the -same sizev 75
o'veriymg the base apertures 1a and 80,15 drawn
~down into the tapered countersink by the tapered
' portion of the rivet head.
The resistance el
ment in _this _position forms a lining- for the
countersink and coacts with the rivet head to
The rivet
head being flush with the resistance element’s
contact surface permits the contactor member to
. ' pass‘beyond the effective resistance area during
the actuation of the switch mechanism.
terminals there canl be' no~ inadvertent bending
of any of the terminals so that the terminal riv
In orderto prevent 'any damage to the resist
ance element great 'care mustjbe 'exercised in fas
20 tening'the rivets 82 and 84‘to the ends of the
resistance element. ‘l The_‘most suitable manner is
to expandthe’tip M_ of the bolt at a plurality of
points 96, ‘98. |00, and |02 as shown in Figs. 9, 10
and 11.
A rivet |04fof conducting material, see Fig. 3,
attached to the tab '32 of the nexlbie disk-E and
ets may be disturbed which~might result in ran'in
creased 4minimum resistance, particularly at the
low'resistance end of -the resistance film; '
' Furthermore, the terminal arrangement' here
inbefore described prevents >the inadvertent press
ing of the terminal >against themetal panel for
the radio set to complete a short-circuit‘which
short-circuit may do considerable'damage during
the testing or inspection of the radio set.
My preferred form of rlieostat` construction
lends itself quite readily tothe tandem or double
type of rheostat in which a second or -duplicate
rhecstat structurels placed over the ñrst rheo
stat in place'of'the cover J.
-« -
‘ an intermediate’electrical terminal |06 provides
In Figurel2 is shown another modification of
the pad-holder blank.' lA tail 200«merging into a
the electrical take-.oir 4for the variable4 contact on
body portion 202 has material for'wings 204`and
Switch operation
206 at each end adjacent a head“ portion 208.
My rheostat-may, also,~be used in conjunction
with the operacion of _áfsriaplswitch s, whereby
"a rotary or oscillatoryfmovement of the pressure
Shoulders ||8 and |20 extend from the neck Ill
of suilicient width to rest and engage the opposite
face of the mounting base A so that movement of
the terminal in any direction is prevented. The
shoulders then taper or merge into a lug portion
until the notch or eye |22 is reached, thus when
the various lead- wires are being attached to the
' _The openingsgßâ and 3_8 vthrough the conduct
ing ends of the` resistance‘element, see Figs. 4,9
and 10, are'of the samediameter as the openings
18 and 80"throù_gh_'_the^base, andas the `rivets are
of electrical‘co'nducting materialaìthe electrical
circuit from the‘ends'of the resistance element to
the outside terminals _90 andï92 will be completed.
the mounting plate to prevent the terminalmem
ber from being turned with respect to this plate.
arm over‘a short peripheral length of the* cir
Upon forming the blank,'as shown in Figuresl3 30
and 14, the‘tail 2001s offset from fthe body 202
andthe head 208 is bent ina U-shaped formation
which together with the wings '20( and 206 forms
a basket or receptacle for the pad,- which pad
> preferably may'have'- irregular sides.
cumferenceï actuatesfbperably connected mech
Although this invention has been described-in
anism to~ open or'close the snap switch.' However, _ considerable detail; such descriptionjïis'» intended
.the relationship óf-’theïswitch to` the rheostat' is as illustrative ratherthan limiting, as',the'inven-
' such that noneo'f theeifectiv'e conducting surface
«of the resistance element between the zero re
sistance, terminal e and '~ the -maximum resistance
terminal is _contacted by the interposed member
upon movément'of‘the pressure arm, during the
operation of the'switch; A
"In'fordertoprovide' for'the operation of the
switch or circuit controller, the pressure or wiper
arm G may be4 provided with a normally project
ing, insulated,“‘eccentrically’ mounted pin |08, see
Figs._1 and 3. This" pin |08 projects normalto
the plane of the pressure arm G and into such
position that it may transiently engage an oper
ating ear | |0 of the switch mechanism S. A tran
sient movement of_the pressure arm G will there
fore operate the switch mechanism. The switch
S, shown by-way offexample, may be any pre
55 i'erredf type of switch suitable for this purpose,
such as for example the switch shown in my
copending application Serial No. 602,006, filed
March 30,1932, to which application reference is
60 here made for the details of construction of the
switch and the manner `of mechanical arrange
As will behest seen in- Figures 1,2, 3 and 4,
the terminal member |06, and the same details
of construction apply to the yterminals 90 and 92,
of a single strip of >cor'xducting material of uni
form thickness, has a foot ||2 connected, by
means of the bolt, rivet, or eyelet | 04 which pierces
70 the base, tothe tab of the interposed disk which
forms the intermediate variable contacting con
ductor. The foot || 2 of the terminal is disposed
' upon the outer face of the base A and has a neck
Ill therefrom bent normal to the plane of the
75 base. The neck fits within a suitable slot ||6 in
tion may be variously embodied,y andthe -scope of
vthe invention is to be determined as claimed.
1. In a variable resistance unit, iii-combination,
a base member, a resistance element mounted on
said base member,- a contactor device adapted to
be moved to vary the eiïective resistance 'of said
element, and a metallic cup-shaped cover secured
to said base member to overlie said resistance ele
ment and contactor device, the’side wallsof the
cup-shaped cover extendingbeyondfthe edges of
the major portion of the base member, the cover \
being spaced relative to the base member by an
upstanding cylindrical band of insulation disposed
adjacent inner side wall portions ofsaid cover.
2. In a variable resistance device, a circular
base member having a resistance element and a
contactor mounted thereon, a cylindrical cup
shaped casing telescoped snugly upon said base
member to overlie said resistance element and
contactor, the side walls of the cup-shaped cover -60
extending beyond the edges of the major portion
of the base member, a band of insulation dis
posed around the inner periphery of the side wall
portion of the casing and being of less width than
said side wall portion, the- edge of said band ad 65
jacent the open end of the casing being adapted
to engage the inner surface of said base member.
3. In a circuit controller unit, a base member
having circuit controlling devices mounted there
on, terminal members projecting outwardly from 70
said baser member, a metallic cover telescoped
upon said base member having an aperture there
in to provide clearance from terminal members,
and a band of insulation interposed between por
tions of said cover and said-base member to main
tain a predetermined spaced relation therebe
tween and to close said aperture.
4. In a variable resistance device, a base mem
ber, a resistance and movable contactor carried
thereby, a cup-shaped metallic casing, having
ears depending from its free edge, telescoped
upon said base member to overlie said resist
ance and contactor, a strip of insulation lining
the side walls of the casing which is of less
ilu width than said sidewalls, the edge of said
strip adjacent the open end of the casing adapt
ed to engage the inner surface of said base mem
ber adjacent its edge, said ears being bent to
engage the outer surface of said base at periph
eral points to hold said strip and base member
in firm engagement.
5. A variable resistance unit comprising a base
member, resistance varying means mounted on
said base member, a metallic cup-shaped cover
telescoped upon said base member to overlie
saidresistance varying means, a ñexible band of
insulation disposedk around the inner face of the
side walls of said cover, an edge of said band
forming a yieldable bearing shoulder to engage
said base member, a plurality of tongues extend
ing from the free edge of said cover adapted to
engage said base member to hold it in ñrm
engagement with said yieldable bearing shoulder
to eilîectively seal said unit.
6. In combination, a variable resistance device
comprising a base portion having a resistance
and resistance varying means mounted thereon,
a cover member therefor comprising an end
wall, a side wall depending therefrom, said side
wall having an irregular edge composed of ap
ertures and ears, a flexible insulating strip dis
posed adjacent the inner face of said side wall
spacing said cover from said base, said ears be
ing crimped inwardly to engage said base por
40 tion to retain said cover thereon.
7. A variable resistance unit comprisinga base
member having a peripheral projection thereon,
resistance varying means mounted on said base
and switch actuating means mounted thereon, a
cup-shaped metallic cover telescoped upon said
base member to overlie said resistance varying
and switch actuating means, a switch device
mounted upon the end wall portion of said
cover having a controller projecting there
through, insulating means disposed between said
base member and the end wall portion of said
cover for effecting a predetermined spaced rela
tion therebetween to permit cooperation between
said controller and said switch actuating means,
and a plu'rality'of fastening tongues extending
from the free edge of said cover bent to engage
said base member whereby the integrity of the
unit; thus formed is preserved.
9. A rheostat comprising a base of insulating
material, a peripheral extension on said base
having extending edges, a plurality of terminal
members, a plurality of recesses in said exten
sion wherein each recess has a terminal member
complementary therein, a cup-shaped metallic
casing for said rheostat including a plurality of
holding and positioning members extending from
a peripheral edge of said casing, and two of said
positioning members located immediately adja
cent Athe edges of said peripheral extension
whereby the casing is located in a predetermined
position on said base.
10, In a combination rheostat and snap switch
unit, a single control shaft Tor the unit, a base of
insulating material, a resistance element mount-`
ed upon said base, a peripheral extension on said
base having a plurality of grooves therein, a plu
rality ofk complementary electrical terminal
members interfltting into said grooves, a con- :~;."
tact member for selectively engaging said re
sistance element, means for moving said contact
member from said control shaft, means for op
erably connecting said terminal members to said
resistance element and said contact member, a
substantially cylindrical housing member hav
ing one end substantially closed, said substan
tially closed end having a small opening therein,
a snap switch casing securely fastened to the
substantially closed end of said cylindrical mem
member, a shield telescoped snugly upon said
base to overlie said resistance varying means,
said shield comprising an end wall with side . ber whereby the snap-switch casing overlaps the
walls depending therefrom, a notch in the free said small opening, snap switch mechanism, a
edge of said side walls registering with said pro
fork-like trigger of said‘ snap switch mechanism
jection to prevent rotative movement between projecting through said small opening, an ec
50 said shield and base member, a. plurality of ears centric for rtransiently engaging said fork-like
integral with said side walls depending from said trigger and suitably connected to said control
free edge, a cylindrical band of insulation sur
shaft, a plurality of holding and positioning
rounding said resistance varying means disposed members extending from the peripheral edge of
entirely within said shield to forceably bear the open end of said cylindrical housing member.
upon said base member adjacent the edge of its and two of said positioning members located-im
mediately adjacent the edges of said peripheral
inner face, said ears being bent inwardly to en
gage the outer surface of said base member extension whereby the cylindrical member is lo
whereby said forceable engagement is main
cated in a predetermined position on said insul- .
ating base so that the snap switch trigger may
8. In a combined variable resistance and switch be actuated by said eccentric.
unit, a base member having resistance varying
Без категории
Размер файла
991 Кб
Пожаловаться на содержимое документа