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Патент USA US2138210

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Nov. ¿29, 1938.
N. c. SCHELLENGER
2,138,210
CONTROL DEVICE
Filed Feb. 17, 1934
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N. c. SCHELLENGER
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CONTROL DEVICE
Filed Feb. 17, 1954
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CONTROL DEVICE
Filed Feb. 17, 1954
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N_ C SCHELLENGER
2,138,210
CONTROL DEVI CE
Filed Feb. 17, 1934
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Patentedv Nov. 29, 1938
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UNITED STATES PATENT OFFICE>
2,138,210
CONTROL DEVICE
Newton C. Schellenger, Elkhart, Ind., assignor to
Chicago Telephone Supply Co., Elkhart, Ind., a
corporation of Indiana
-
Application February 17, 1934, Serial No. 711,1644
7 Claims.
(Cl. 5301-55)
This invention relates to improvements in variable resistance devices of the type commonly
ing through the terminal sector on a part of the
resistance element that could not be used other
employed as volume and tone control apparatus Wise, the present invention allows this to be done
in radio sets,`public address systems and the like. more satisfactorily as no portions of the terminal
5
More particularly this invention relates to ter- member lie in the path of the contactor and the 5
minals for variable resistance devices in which contactor can be moved through 360° if desired
the resistance element is of the flat composition »
Since no portion of the terminal lies in the path
type against which. the terminals are adapted to of movement of the contactor, there is no pos
be clamped, and relates also, to aterminal co- l Sibilîty 0f engagement between these members
10 operating with other means to make connection
with a movable contact member.
This invention further relates to a combination variable resistance device of the aforementioned type and a switch or other associated .de-'
.15 vice operatively connected to the variable resistance device for operation thereby when the con-tactor or other. adjustable element is moved
through a predetermined portion of its travel
>normally beyond the end of effective portion of
20 the resistance element.
For some time, the radio trade has been de>manding the smallest possible rheostat for volurne and tonev control purposes that can be furnished without sacriñeing smoothness of opera-
and hence the present invention eliminates any 10
possibility of sudden variations in resistance due
to transient metal to metal contact between the
contactor and terminal, and also eliminates any
possibility of the scoring of the polished surface
of the contactor by the terminal.
l
15
It is well known that terminal members have
been used to clamp onto wirewound resistance
elements in various ways but none of them Vsolved
the above mentioned problems. In fact none of
them were adapted to clamp onto airagile re- 20
sistance element of the composition type regard
less of whether or not the other problems were
Solved.
One object of this invention is to provide a
25 tion or accuracy of the resistance gradient. In
terminal for a variable resistance device that can 25
-order to meet this demand it was necessary to »y be securely clamped in place so that no auxiliary
reduce the width of the sector occupied by the
holding means are required.
resistance element end terminals and the mov-
~ Another object 0f this inVentìOn iS to DI‘OVÍde a
»able `contactor terminal to the lowest possible
30 limit in order that the maximum length of effec'tive resistance element might be maintained for
useful variation in resistance.
-
In many cases it is also required that a power
switch be added to the variable resistance device
35 and be- operated by angular movement of the
operating shaft of the variable resistance device,
usually through an angle adjacent one of the
,
.
terminal that makes good electrical contact with
the resistance element outside the path 0f the 30
contactor and has no parts directly engageable by
the contactor,
_
Another object of this invention is to provide
a terminal with an ear that can easily be bent
into contact with the resistance element without 35
damaging the resistance element.
\
Another object of this invention îS t0 Dl‘OVíde
rotational limits of the movable contactor. Prior
a ñxed terminal means for tapping the resistance
to the invention disclosed in my application Se- v element _Outside the Def/h 0f the mOi/able C011
40 rial N0_ 692,665, med October '7I 1933,11; was com..
taeter and at a position intermediate the end 40
mon practice to operate the switch as the movable
terminals Without appreeìably affecting the total
contactor of the variable 'resistance device apresistance of the resistance element and also pro
proached one of the end terminals of the resistviding a low minimum resistance between the
ance element.
However, to permit this, it was
4 5 necessary to short circuit that portion of the'
resistance element vtraversed by the contactor
during the switch operating portion of the contactor movement and as a result the expense of
l manufacture was increased and the eiîective‘por-
terminal and the‘contactor.
Another object of this invention is to provide 45
a terminal for the movable contactor which pro
vides a positive electrical and mechanical con
nection with a member in the electrical circuit
between the terminal and the movable contactor.
.
50 tion of the resistance element was crowded into
a much shorter space which greatly impaired the
smoothness of control of the radio set. z
Another object of this invention is to provide 50
a terminal that occupies an extremely narrowl
sector of the variable resistance device base.
While the above mentioned invention made
available for operation of the switch, the portion
5,5._ of rotation during _whichthe contactor >was mov-
Another object of this invention is to provide
a combined variable resistance device and switch
_in which the switch can be operated while the 55
o
Á
2
2,138,210
movable contactor is moving _through the sector
of the base of the variable resistance device oc
cupied by the terminals.
With the above and other objects in view which
will appear as the description proceeds, my in
vention resides in the novel construction, com
bination and arrangement of parts substantially
as hereinafter described and more particularly
deñned by the appended claims, it being under
stood that such changes in the precise embodi
ment of the hereindisclosed invention may be
made as come within the scope of the claims.
In the accompanying drawings, I have illus
trated complete examples of the physical embod
15 iment of my invention in which:
Fig. 1 is a plan view of the variable resistance
device of my invention with the cover removed;
Fig. 2 is a partial elevational view in section
taken along the line 2-2 of Fig. 1;
Fig. 3 is a sectional elevational view taken
along line 3-3 of the rheostat shown in Fig. 1;
Fig. 4 is an isometric view of a partially com
pleted terminal;
Fig. 5 is an isometric view of a. terminal ready
25 to be mounted on the rheostat;
Fig. 6 is an end view of one of the terminals of
my invention assembled in place in the rheostat;
Fig. '7 is an elevational view of the terminal
after assembly in the rheostat With the base and
30 resistance element sectioned;
Fig. 8 is a view taken from the opposite end of
35
that shown in Fig. 6;
Fig, 9 is a plan view of a part of the rheostat
base showing notches and holes for mounting of
terminals;
Fig. l0 is an isometric view of a partially com
pleted terminal of slightly modified construction;
Fig. 11 is an end View similar to Fig. 8 of a
slightly modiñed terminal;
40
Fig. 12 is an isometric view of one element of
a two piece terminal;
Fig. 13 is an isometric view of the other ele
ment of the two piece terminal;
' Fig. 14 is a side View of a two piece terminal
assembled in the rheostat, with other parts of
the rheostat shown in section;
Fig. 15 is an enlarged portion of Fig. 14 showing
the bent over end of the terminal;
Fig. 16 is a plan view of the terminal of Fig. 14
50 assembled in the rheostat;
Fig. 17 is an elevational view, with some parts
broken away, of a rheostat with a switch mounted
on the cover -and adapted to be operated by ro
tation of the rheostat shaft;
55
60
~
Fig. 18 is a sectional plan view of the rheostat
and switch operating member taken along the
line l8-i8 of Fig. 17;
Fig. 19 is a partial plan view showing the mov
able parts in a certain position;
Fig. 2O is a partial plan view showing the mov
able contactor in a certain position;
Fig. 21 is a partial plan view showing the mov
able contactor in another position;
Fig. 22 is another partial plan view showing
the movable contactor adjacent the tap termi
na ;
Fig. 23 is ariothM partial plan view showing
the movable contactor in another position;
Fig. 24 is a reduced bottom plan vier.' showing
the base with terminals attached; and
Figs. 25 and 25 are enlarged frag
and sectional views respectively show of - modified construction.
Referring to the drawings more in detaii
dan,
variable ‘resistance device
comprises o.
i
formed of insulating material, such as a phenol
condensation product, or the like, on which is
mounted a resistance element 3, which may be
formed by coating a strip of heavy paper with a
carbonaceous conductive composition. In other
cases the resistance element may preferably be
formed by applying the conductive coating di
rectly to the base 2. Usually it is desirable to de
posit a low resistance coating on the section of
the resistance element that will be engaged by
terminals 4 and 5 so that a low minimum re
sistance between the terminal and the movable
contactor can be obtained. These low resistance
coatings are preferably tapered in thickness at
the ends so that there will be no sudden change
inthe rate of resistance variation as the movable
contactor passes from one section to the other, as
is shown and described in my copending applica
tion Serial No. 666,444, iiled April 17, 1933. End
terminals 4 and 5 make connection with the ends 20
of the effective portion of the resistance element
3 and provide a means of connecting an external
circuit with the ends of the resistance element.
A movable contactor 6 is pressed into contact
with the resistance element 3 by the pressure 25
arm l which terminates in a tip 8 that is tapered
to engage the edges of the hole 9 in the contactor
6 so as to accurately position the latter on the
resistance element. The pressure arm 'I is posi?
tioned on the drive plate I0 by two diametrically 30
opposed ears II and I2 formed up from the body
portion of the arm 1 on a center line which is at
90° to the center line passing through the tip 8
so as to engage two corresponding notches on the
drive plate I0. The drive plate IU is secured to
the shaft I4 through the co-operation of a flatted
reduced end I5 on the saft I4, a hole of corre
sponding shape in the drive plate, and a washer
I6 fitted over the reduced ñatted end I5 of the
shaft I4 and the flatted end peened over to hold 40
the members all in pressure engagement.
Centrally located in the base 2 is a bushing
I1 having a shoulder I8 which is knurled around
its outer portion to provide teeth which penetrate
the surface of the base 2 when the bushing is
pressed into place. On the other side of the base
2 is a washer I9 that fits over another shoulder
20 on the bushing. The base 2, bushing I1 and
washer I9 are all held securely together by swag
ing the shoulder 20 of the bushing into engage
ment with the washer I9. Preferably the washer
i9 has a tapered hole formed with the large end
away from the base so that the portion of the
shoulder 20 that extends beyond the washer I 9
before swaging, can be swaged into the hole
leaving
the mounting surface substantially
55
planar. The shaft I4 is journaled in this bush
ing I'I and is positioned longitudinally by a shaft
collar 2l and washer 22 bearing against one end
of the bushing Il and opposing the thrust be 60
tween the drive plate I 0 and the bushing Il
which is exerted by a spring member 23 located
between the drive plate I0 and the pressure
arm l. This spring member is spaced from the
shaft by projections on the rim that form notches
which engage the ears II and I2 bent up from
the body portion of the pressure arm 1. The
body portion of the pressure arm l is pressed
against
spaced
collector ring 24 that is insulated and
the bushing by a washer 25 of fibre
or other sui"able material and connected to the
terminal
by a reduced section 2S’ of tail 26
extendir. through a hole §23 in the ear 28 of the
3
2,138,210
drives the pressure arm 1 which is in'engagement
with the contacter 6 so that the contacter is
moved along the resistance element and passes
very close to the bent over ear 50 of the tap
terminal 48 and, when no switch is used, the
drive plate I8 strikes a suitably positioned stop
ear, not shown but similar to 85 (Fig. 18), pro
jecting in from the cover 80 so that the contacter
6 comes to rest between the bent over ears 3l
and 32 of terminal 4 at one end of rotation. Ro
tation in the other direction/is limited by the
drive plate I8 striking the stop ear 85 and bring
ing the contactor to rest between the bent over
ears 45 and 46 of terminalv5.
15
_
Referring more particularly to the terminals
of my invention, it is to be noted that` they may
be brought very close together and yet allow a
I sufficient spacing between terminals to provide
the necessary insulation and also to provide a
20 maximumeffective length of resistance element.
I have accomplished this by tapering the body
section of the terminal so that the angle occupied
by the terminal is approximately the same'or in
some cases slightly more at the outer end than
V25 at the inner end, which provides
sufficient
strength at the outer portion to withstand the
forces that may be imposed during attachment of
a conductor. This same effect could be obtained
by any means of narrowing the inner end of the
30 terminal such as by providing one or more steps
in width of the body portion. The inner end,
where great strength is not required, is much nar
rower and1 is adapted to be clinched over onto the
base or resistance element to hold the terminal
35 in place and in the case of the end terminals,
also make contact with the resistance element.
Referring more in detail to Figs. 4 to 8, the
terminal comprises a terminal proper or body
portion 36 which is formed with a head portion
40 38 having ‘ laterally extending wings 38', 38"
constituting shoulders, an upturned end portion
34, and an upstanding ear 35. Integral with and
extending from the head portion 38 of the ter
minal 36 is a connection extension (commonly
called at “solder lug”) having a perforated por
tion 33 and a neck 44 of reduced width. Adjacent
the tip 3l of the upturned end 34 is a reduced
section or neck 43 and adjacent the tip 32 of the
ear 35 is a reduced section or neck 31.
This terminal 4 can be easily manufactured by
punching a piece out of sheet brass or other suit
below the surface of the resistance element 3 so
that when the ltips 3l and 32 are bent over onto
the resistance element 3, their contacting sur
faces will be substantially parallel with the sur
face of the resistance element 3 when they meet
the latter, due, as previously stated, to the bends
occurring at a point predetermined by the loca
tion of the reduced sections. The reduced sec
tions also permit the end 34 and the ear 35'to be
bent over onto the resistance element 3 with a 10
more even `and accurately predetermined pres
sure than would otherwise be possible; Thus a
uniform contact pressure between the terminal 4
and the resistance element 3, and consequently,
al uniform contact resistance between these ele 15
ments can readily be obtained. Furthermore the
provision of reduced sections makes it possible
to obtain these results without damage to the
very thin and fragile conductive coating of the
20
resistance element.
The thickness of this coating is in most cases
only one or two thousandths of an inch and as a
result the resistance element can be very easily
damaged by any excessive pressure on any part of
its surface such as would be created by the sur
face of the terminal ears meeting the conductive
coating unevenly _as they are bent over into their
final position.
The exact width, length and position of these
reduced sections necessary to iorce the bending 30
to occur in them without distorting other parts of
the ears and to allow the end to bebrou-ght into
viirrn coplanar contact with the resistance element
over the maximum area depends largely upon the '
35
kind . and thickness of metal used for the ter
minal and can best be determined by trial.
Where it is desired to provide a variable resist
ance device having an extremely low contact re
sistance between the terminal and the resistance
element, a soft pad of conducting material is in
terposed between these elements.
_
Such an arrangement is shown in Figs. 25 and
26 wherein a pad 38 is constituted of soft sheet
metal or metal foil having originally a U shape
and is inserted in the openings did, 42d and 45
pushed up against the base 2d. The terminal 4d
is then inserted in a manner similar to that de
scribed in connection with the terminal 4 and
the tips 3 Id, 32d are bent over to clamp the ends
9i, 92 of the pad 9D against the contact surface 50
of the resistance element 3d.
'
` .
As the pad y80 is soft it adapts itself to the con
able material to shape shown in Fig. 4 with the
exception that the ear 35 sheared out of the body tours of the surfaces of the resistance element
portion 36 and formed at right angles has no re ' 3d and the terminal 4d respectively and thus has
duced section 31. A separate trimming operation an area of intimate contact with both members
is employed to cut notchesout of the sides and respectively which is greater than the area of
create this reduced section 31 that serves to force contact between the terminal and resistance ele
the bending line to the desired point when the ment when these latter elements are in direct
contact and no pad is employed.
tip 32 is bent over on the resistance element.
An equivalent result may be obtained by inter
Another. forming operation gives the terminal
60
of Fig. 4 the shape shown in Fig. 5, the shape in posing between the resistance element and the
tips which are bent over against the resistance
which it is positioned on the base. The extend
element a section of soft wire, such as fuse wire;
ing wings 38' and 38", formed on a head por
tion 38 of the -terminal proper 36 are hooked when the tips are bent ove'r to clamp the ter
over the lobe 39 which is integral with the base 2' minals on the base, the interposed wire is fiat
and extends beyond the periphery of the cover tened out into intimate contact with the surface
of the resistance element and the tips.` This wire
(Fig. 18) to actas a terminal support. The ter
minal is then slid into the notches 40 and 4l «in thus serves as a cushion for the tips and provides
the base until the end 34 starts to enter the hole a low contact resistance between the terminal
42 in the base 2. The body portion 36 of the and the resistance element.
No auxiliary parts are required to hold the ter
terminal 4 is then pushed up against the under
side of the base 2 so that the tips 3| and 32 of the minal in place against the resistance element as
this is accomplished by the tips 3| and 32 of the
` end 34 and the ear 35 project beyond the face of
the resistance element 3. When in this position end 34 and ear/35 respectively that are bent over
75 the reduced sections 43 and 31 extend slightly
25,
55
60
65
70
onto the resistance element 3 clamping Ithe ter 75
2,138,210
minal 4 tightly to the base 2 and making good
electrical contact with the resistance element 3.
The reduced portion 44 in the connection ex
tension is provided so that it will bend and there
by prevent damage to the variable resistance de
vice if any excessive bending force is applied to
the connection extension, such as might occur
when leads to the external circuit are being con
nected.
Any side thrust applied to the connection eX
tension is resisted by the sides of notches 4i) and
¿il and sides of hole 42 bearing against the sides
of the terminal. Pressure on the connection ex
tension in a direction parallel to the axis of the
shaft ill is resisted in one direction by pressure
of extending wings 38’ and 38" against the lobe
39 of the base 2 and by a light pressure of the
terminal ears and allows a very low minimum
resistance to be obtained and also allows the con
tactor to be moved past ~the terminal if desired,
without touching it or producing any discontinu
ity in the nature of the contact between the
contactor and the surface of the resistance ele
ment, such as might occur if the contacter made
direct contact with the terminal.
W'hen a switch is to be used in combination
back part of the terminal body 3S against the
underside of the base 2. With pressure ín the
adjacent the notch 40 upward against the base 2.
to a position between the ears 3|, 32 of terminal
4 as shown in Fig. 2l, at which point the effec
tive portion of the resistance element 3 ends.
However, at this point a pin 84 on the drive plate
I0 engages an operating member 82 of a switch
In Figs. l0 and l1 I have shown another method
25 of obtaining a reduced or weakened section in
the upstanding ear and upturned end to pos'í
tion the bending line at a point that will allow
the tips to bend over onto the resistance element
and accomplish the same results outlined above.
30
The reduced section is provided in this terminal
|04 by piercing a hole |31 in the ear |35, and a
hole |43 in the ear |34 at suitable positions.
All other parts of the terminal function in exactly
the same manner as described above.
Another modification of the terminal is shown
in Figs. l2 to 16. In this form of ~terminal the
ears that extend through the base are creased
transversely to definitely locate the bending line
instead of having a section cut away as in the
40 previously described forms, and -two pieces are
used so that together they function in a manner
similar to the terminal 4. A member 204 (Fig.
12) is punched from sheet metal and portions of
each end formed up so that when it is in place
45 on the base 2b (Fig. 14) before the clinching op
eration has been performed it will have the shape
shown by the dotted lines. When in this position
the ear 234’ projects into the hole 42h in the base
2b and fits closely against the wall of the hole
closest to the outer rim of the base 2b. The other
ear 235 on this member ñts snugly against the in
side wall of the notch 4|b in the base and the
creased section 237 falls at a position that per
mits bending the tip 232 over against the resist
55 ance element 3b and making good contact with
it over the maximum area and without damage
to the conducting surface.
A second flat member 204’ (Fig. 13) is punched
from sheet metal and formed as shown in Fig. 14
60 with the tip 23| of ear 234 in the position shown
~ by the dotted lines. Member 284’ is placed in po
sition with the wings 238’ and 238” of the ter
minal bearing against the upper side of the lobe
39D, the body portion 236 against the body por
65 tion 236’ of the member 204, and the ear 234
extending up through the hole 4217 in the base 2b
and fitting snugly against the ear 234’ of the
member 204.
The creased section 243 is at a
point that permits bending the tip 23| into ñrm
70 engagement with and over a maximum area of
the resistance element 3b. In other respects the
parts of this two piece terminal function in the
same manner as the corresponding parts of the
single piece terminals.
75
as far as possible and still fall short of the 'path
of movement or race-way of the contactor by
several thousandths of an inch. This provides
two very short paths between the contactor and Ul
the terminal when the contactor is between the
with the variable resistance device, the switch is
preferably located so that it is not engaged while
the contactor 6 is being moved from the effective
portion A of the resistance element 3 (Fig. 18),
20 other direction there will be a slight pressure in
crease of the bent over tip 3| on the resistance
element- 3 and a pressure of the body portion 36
35
enough to bend over onto the resistance element
’
All of the above terminals have the tips long
8| mounted on the cover 8U of the variable re
sistance device. For constructional details of
this switch, reference may be made to my co
pending application Serial No. 599,490, filed No
vember 24, 1933.
~
Movement of the contactor 6 on past the ter 30
minal 4 onto the portion B operates the switch
8| so that the latter is thrown into the open cir
cuit position before the stop ear 85 in the cover
80 is engaged by the drive plate I0. When the
switch 8| is in the open circuit position and the
drive plate IO is against the stop 85 the con
tactor 6 will be in the position shown in Fig. 20.
The portion of the resistance element 3 over
which the contacter 6 travels during operation
of the switch 8l and which is ineffective to pro
duce any variation in the effective resistance fur
nished by the variable resistance device |, may
have a very low resistance coating deposited on
its surface so that the effect on the external
circuit will be practicall’y the same as though the
contacter 6 were short circuíted to the adjacent
end terminal 4 or, when this effect is not desired,
a high resistance coating may be applied to the
resistance element 3 over this range. If desired,
the coating may be terminated at or just beyond .
the terminal 4 by providing a wider section 95
which carries no conductive coating, so that the
contactor 6, when moving through the greater
part of the switch operating portion of its travel,
does not engage the conductive surface of the
resistance element.
When the drive plate is rotated in the opposite
direction the switch operating member 82 is en
gaged by the pin 84, and the switch 8| is thrown
to the closed circuit position before the contactor 60
E passes out from between the terminal ears 3|,
32 and onto the effective portion A of the re
sistance element 3. When the shaft |4 is rotated
to its limiting position in this same direction the
stop ear 85 will be engaged by the other side ol'
the stop portion of drive plate l0 at which time
the contactor 6 is directly between the bent over
ears 45 and 46 of terminal 5 as shown in Fig. 23.
It is often desirable to provide a fixed tap con
nection on the resistance element at a point in
termediate the end terminals and „when this is
desired a terminal of the type shown in Figs. '7,
11 or 14 can be used.
An extension or lobe 41
(Figs. 1 and 22) is provided on the base 2 and
is notched for terminal 48 similar to the man-v
75
5,
2,188,210
’ ner in which lobe 39 is notched for either of the
end terminals 4, 5.
The terminal 48 is assem
bled in the same manner as the end terminals
4, 5 except that the ear 49 closest to the center
of the base 2 is not bent over onto the resistance
element 3 but is bent over onto the insulating
base 2 instead. In order that no appreciable
amount of the resistance between the end termi
nals 4, 5 be short circuited,` only the outer ear is
bent into contact with the resistance element 3.
If the inner ear 49 were bent over onto the re
sistance element 3 a considerable proportion of
the total -'resistance would be short circuited since
the inner marginal portion of the resistance ele
ment 3 is the shortest and provides the lowest
resistance path between the end terminals 4, ‘5
and consequently exerts the greatest influence on
the overall resistance of the resistance element 3.
When a very low minimum. resistance between
20 the tap terminal 48 and the movable contactor
6 is desired a low resistance composition is de
» posited, prior to the assembly of the tap terminal
48, on that portion of the resistance element 3
where the tap terminal 48 is to be located. Pref
25 erably this low resistance coating 5l (see Fig. 18)
is applied in the general shape of a triangle with
the base at the outer rim of the resistance ele
ment 3 where the ear 50 of the tap terminal 48
will be clinched over and with the apex of this
30 triangle toward the center of the variable re
sistance device I. In most cases it is desirable
that the edges of this low resistance coating 5l
be tapered so that there will be no suddenchange
in the rate of resistance variation as the movable
35 contacter 6 moves onto or 01T of this section of
the surface of the resistance element 3. With
the low resistance coating 5| applied'in this gen
eral shape and position no appreciable amount
of the effective resistance of the resistance ele
40 ment 3 is short circuited and a very low minimum
resistance is obtained between the contactor t
and the tap terminal 48 when the contactor 6
is adjacent the tap terminal 48 and bearing on
the low resistance coating 5l. The distance that
45 the apex of the low resistance triangular sector
5l is made to extend toward the ear 49 will de
pend upon the conditions desired.
bent over onto the base into the position shown in
Fig. 3. This securely clamps the reduced section
26’ of ‘the tail 26 under the terminal and also locks,
the section 26’ into the hole 28 due to the sides of
the holesqueezing in against the sides of section
26' when thefear is bent over.
Thus a connec
tion of low electrical resistance and great me
chanical strength is formed between these mem
bers with a minimum of parts and labor.
I claim:
,
l. A variable assistance device comprising a
base, a plurality of apertures in said base, a re
sistance element comprising a support and a
conductive film carried by said support, disposed
on said base between said apertures and having a 15
relatively smooth contact surface, a terminal for
said resistance element extending between said
apertures and having portions registering therein
for eii‘ecting self-clamping engagement with
said base and said resistance element, and ad 20
justable contacting means engageable with said
resistance element for varying the effective re
sistance of the device.
2. A variable resistance device?comprising a
base, a plurality of apertures in said base, a re
sistance element comprising a support and a con
ductive film carried by said support, disposed on
said base between said apertures and having a
relatively smooth Contact surface, a terminal ex
tending between said apertures having portions 30
registering therein for engaging said base, said
portions being bent over into clamping engage
ment with the conductive ñlm of said resistance
element, and adjustable contacting means asso
ciated with the contact surface of said resistance 35
element for varying` the effective resistance of
the device.'
3. A current controlling device comprising a
base having a recess in a peripheral portion, a
wire _connecting terminal mounted on said base, 40
said terminal having a body portion mounted on
one side of said base and extending to seat in said
recess, a shouldered portion bearing against the
other side of said base adjacent the recess, a wire
connecting portion extending from said shoul 45
dered portion away from said other side of the
base, and means extending through said base for
said body portion to said base.
The terminal 21, electrically connected to the securing
4.
A
current
controlling device comprising a
movable contactor 6, is also of the clinch-on type
‘base having a recess in the peripheral portion 50
50 which permits rapid assembly and requires no
thereof and a terminal seated in said..recess, said
auxiliary parts to hold it in place. The connec
having a shouldered portion engaging a
tion extension 51 has a reduced section 58 which terminal
first
face
of said base, a wire connecting portion
will bend before the base 2 or any other part of
extending from said shouldered portion away
the terminal 21 is damaged by a bending or twist
from said ñrst face of said base, and a body por 55
55 ing force applied tcLthe end of the terminal 21,
tionY extending along the second face of said base
such as might occur when a wire -is being at
tached to the terminal 21. The extending wings and extending through an opening in said base,
60 and 6I bear against the upper side of lobe 39 the end of said body portion being bent over to
on base 2 when the portion 63 is seated in the ward said base to clamp said end against said
60 notch 64 in the lobe 39 of base 2 and the body
portion of the terminal 21 bears against the other
side of the base 2. The end 29 of the terminal
21 is bent up from the body portion 62 and ex
tends through the hole 61 in the base 2 fitting
snugly against the outer edge of this hole. Ap
proximately even with the inner surface of the
base 2 is a hole 28 in the end 29 and beyond is a
tip portion 68 clinched over against the base 2.
The collector ring 24 has a tail 26 formed as
shown in Fig. 3 that terminates in a reduced
tapered section 26’,which is> projected through
the hole 28 in the terminal 21 so that the shoul
der on the tail 28 at the base of the reduced sec
tion 26’ bears against the terminal adjacent the
75 wall of the hole 28. The tip 68 of end 29 is then
60
base.
5. A variable resistance device comprising a
base, a resistance element comprising a support
and a conductive film carried by said support,
disposed-on one surface of said base, a contactor
engaging the surface of said resistance element, 65
means for -moving said contacter over the surface
of said resistance element, and a terminal secured
to said base and having a body portion extending
along the under surface of said base and a con
tact portion extending through said base and
bent. into engagement with the upper surface of
said resistance element, said terminal having a
reduced transverse cross-sectional area provided
at the point of bending, adjacent said contact
y portion.
76
6
2,138,210
6. A variable resistance device comprising a
base, a resistance element comprising a support
and a conductive ñlm carried by said support,
on said base and a terminal for said resistance
element including a member extending along said
base, said member having a portion projected
through a perforation in said base and bent over
to secure said member on said base and a second `
member comprising a pad 0f soft conductive
material clamped between said base and the body
of said first member and having a portion engag
ing the surface of said resistance element.
'7. In a variable resistance device, a base, a
resistance element comprising a support and a.
conductive film carried by said support, on said
base, a contacter movable on said resistance ele
ment through a predetermined path, a terminal Ol
for said resistance element, tail-like portions on
said terminal extending through said base, one
of said tail-like portions being bent over into en
gagement with the conductive surface of said
resistance element outside the path of said con- 10,
tactor.
NEWTON C. SCHELLENGER.,
CERTI- FI CA TE OF|` CORRECTI ON..
Patent No. 2,158,210.
November 29, 1958 .
NEWTON C., SCHELLENGER.
it is hereby certified that error appears in the printed specification
ofthe abo ve numbered patent requiring correction as follows: Page 5, second
co lumn, line ll, claim l, for the word "assistance"
read resistance; and
that the said Letters Patent should be read with this correction therein
that the same may conform to the record of the case in the Patent Office.
Signed and sealed this 7th day of February, A. D. 1959.
tHenry AVan Arsdale.
(Seal)
Acting Commissioner of Patents.
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