United States Patent [19]
[11]
4,373,155
Dola
[45]
Feb. 8, 1983
[54]
BRAKE FLUID LEVEL INDICATOR
.
[75]
Invento?
Frank P- Dola, Port Rlchey, Fla-
3,786,464
l/ 1974 Staemp?i .......................... .. 340/623
3,812,308
5/1974 Bell et al.
ZOO/61.52 X
3,866,470 2/1975 Millet ................ .. 340/623 x
[731 Assigm AMP Incorporated’ Harrisburg, Pa‘
1:322:53? Z133; 313L255?
[21]
Appl. No.: 320,646
4,139,750 2/1979 Rau ..................... .. 200/84 R
[22]
F1led=
[51]
[52]
Int. Cl.3 ...................... .. G08B 21/00; HOlH 3/16
US. Cl. ................................. .. 340/623; 73/ 322.5;
[58]
Field of Search ............... .. 340/623, 624, 625, 59;
,
Nov- 12, 1981
322-5, 321
4,262,216
4/1981 Johnston
200/84 R x
4,308,725
1/1982 Chiyoda
..... .. 340/623 x
Ian-man, Examiner__john w_ Caldwell, SL
Assistant Examjner_Danie] Myer
ZOO/84 R
zoo/61.52, 84 R, 84 0; 73/308, 313, 309, 318,
3131:: 331252?
Attorney, Agent, or Firm—F. Brice Faller
'
'[571
ABSTRACT
References Cited
Fluid level indicator comprises a ?oat suspended at the
apex by wires from the cover of a ?uid reservoir. The
U-S' PATENT DOCUMENTS
rated by an intermediate piece having a concave surface
[56]
?oat has an upper chamber and a lower chamber sepa
2,588,667 3/1952 Stutzman ..................... .. 73/3225 x
2,600,659 6/ 1952 Koch, Jr. .
340/623 X
facing the apex- A metal ball in the upper chamber rolls
into a depression at the center of the surface to bridge
340/625 X
two switch contacts when the ?uid level is low and the
2,743,373
5/ 1956 Fem? ----- '
3,090,849
5/1963
Coulm 3 - - ~ - - - - -
- ' - ' -- ZOO/84 R
?oat is suspended by the wires, which are connected to
3'145’727 8/1964 Yamashna
73/322'5 x
the contacts. The ?oat is top-heavy and rolls over to
3,291,934 12/1966
73/308 UX
Mealy ........ ..
3,309,687 3/1967 Phipps
3,393,283
3,543,580
7/1968 Lenning
12/1970
McGill
340/625 X
_____ __ 73/322_5 X
........ .. 73/313
3,545,272 12/1970 McGill .......................... .. 340/623 X
.
.
.
.
open the sw1tch when the ?u1d level 1s‘h1gh enough to
perm1t the suspending portlon of the w1res to slacken.
'
V
,
5 Claims, 3 Drawing Figures
_
d’zo
U8. Patent
4,373,155
Feb. 8, 1983
2.4.1
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(/26
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/22
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1
4,373,155
2
FIG. 3. The wires 28 then pass out through an aperture
in the center of the ?oat top 11 at the apex of the upper
chamber 13 and thence snugly through an elastomeric
BRAKE FLUID LEVEL INDICATOR
‘ BACKGROUND OF THE‘ INVENTION
seal 26 in the cover 22 on reservoir 20. The ?oat 10
remains canted'in reservoir 20 as shown in FIG. 1 as
The present invention relates to a ?uid level sensor or
indicator and particularly to a sensor employing a ?oat
long as thelevel of ?uid 24 is high since the ?oat 10 is
top-heavy and it tends to roll over.
FIG. 2 shows the ?oat 10 upright as it would be when
the level of ?uid 24 is low enough that the ?oat is sus
which closes a switch when ?uid reaches a predeter
mined level.
Prior art brake ?uid level indicators generally em
ploy structure ?xed to the reservoir containing the ?uid 0 pended by wires 28 from the reservoir cover 22. When
whose level is to be indicated. See, e.g., US. Pat. No.
the ?uid 24 reaches this level, the metal ball 17 rolls into
2,819,363; this discloses a ?uid level indicator having a
conductive ?oat member which bridges two electrical
contacts when the ?uid reaches a certain level. The
problem with this and other prior art sensors is com
the depression 16 in concave surface 15 and bridges the
depression 16 to electrically connect the contacts 18,
which closes a circuit to activate a remote indicator
light or other electrical warning device. Since the
length of wires between the ?oat and the cover 22 may
plexity and cost of manufacture, and dif?culty in retrof
itting an existing reservior with an indicator.
be varied by pulling the wires through seal 26, the ?uid
level at which the ?oat 10 is upright and the contacts 18
are bridged may be readily adjusted as desired.
FIG. 3 is an end sectional view of the ?oat 11 top in
the “switched closed” position of FIG. 2. Note the
SUMMARY OF THE INVENTION
The present invention employs a top-heavy ?oat
which is suspended from the cover of the ?uid reservior
by wires connected to a pair of contacts sealed within
the ?oat. The contacts are exposed in the center of a
channels 19 which are molded in the ?oat top 11 to
receive the wires 28. This arrangement facilitates easy
concave surface on which a metal ball rolls to close the
circuit in the manner of a mercoid type switch. When 25 assembly of the ?oat 10 and anchors the wires 28 ?rmly
in the ?oat 10 without clips, cement, or other retaining
?uid level is high, the ?oat ?oats lopsidedly and the
switch is open. When ?uid level is low, the ?oat hangs
upright by the wires and the switch is closed.
The indicator of the present invention is inexpensive
to manufacture and easy to assemble.
means. The contacts 18 are press ?t through molded
openings in the intermediate piece 5.
The above description is exemplary and not intended
30 to limit the scope of the claims which follow.
The indicator of the present invention may be retro?t
to an existing ?uid reservoir.
The indicator of the present invention has contacts
sealed from vapor and foreign matter.
I claim:
1. A ?uid level indicator of the type comprising a'
?uid reservoir having a reservoir cover thereon and a
?oat contained in said reservoir, said ?oat being lighter’
The indicator of the present invention may be easily 35 than an equal volume of the ?uid whose level is to be
indicated, said indicator being characterized in that
said indicator further has means for suspending said
BRIEF DESCRIPTION OF THE DRAWINGS
?oat from the reservoir cover, said suspending
FIG. 1 is a side sectional view of the ?oat in the
means limiting the downward travel of said ?oat
reservoir with the switch open.
when the ?uid level drops, said suspending means
FIG. 2 is a side sectional view of the ?oat in the
de?ning the apex of the ?oat at the point of attach
reservoir with the switch closed.
ment thereto, said ?oat being top-heavy toward
FIG. 3 is an end sectional view of the ?oat.
said apex whereby said apex tends to submerge
when the ?oat is ?oating,
DETAILED DESCRIPTION OF THE
45
said ?oat has an upper chamber and a lower chamber
PREFERRED EMBODIMENT
therein, said chambers being separated by an inter
Referring to FIG. 1, the ?oat 10 of the present inven
mediate piece having a concave surface facing said
tion is shown canted as it would be with an adequate
upper
chamber, said concave surface having a pair
level of ?uid 24 in reservoir 20. The ?oat 10 is com~
adjusted to close the switch at any desired ?uid level.
prised of a hollow, hemispherical ?oat bottom or shell
12 and a hollow, hemispherical ?oat top or shell 11
which is pro?led to ?t tightly against the bottom 12.
The pieces 11, 13 are preferably of plastic and are se
cured together by a plastic cement which also forms a
moisture seal. The ?oat top 11 has in intermediate piece 55
5 pro?led to ?t tightly therein which is also made of
of metal contacts embedded in the center thereof
?ushly with said surface, said surface having a
depression therein between said contacts, said
contacts communicating with said lower chamber
and having wires attached thereat, said wires being
connected to warning means remote from said
reservoir,
said upper chamber having a metal ball therein,
whereby,
separates an upper chamber 13 inside the ?oat top 11
said ?oat hangs upright on said suspending means and
from a lower chamber 14 inside ?oat bottom 12.
said metal ball rests in said depression and bridges
The upper chamber 13 contains a metal ball 17 which
said contacts when said ?uid level is low, thereby
rolls against concave surface 15. The concave surface
15 has two metal contacts 18 imbedded therethrough on
activating said remote warning means, and said
either side of a depression 16 at the center point of the
?oat tends to roll over so that said ball rolls out of
arcuate surface 15 and communicating between lower
said depression when said ?uid level is high.
chamber 14 and upper chamber 13. The contacts have 65
2. The ?uid level indicator of claim 1 wherein said
wires 28 attached thereto in the lower chamber 14
wires form said suspension means.
which are press ?t into channels 19 formed on the inside
3. The ?uid level indicator of claim 1 wherein said
of the ?oat top 11 as will be more readily apparent in
?oat is a spherical member.
plastic and secured by cement. The intermediate piece 5
3
4,373,155
4. The ?uid level indicator of claim 3 wherein said
?oat comprises a hemispherical top piece and a hemispherical bottom piece which are ?t together sealingly,
said intermediate piece being ?xed in said top.
5. The ?uid level indicator of claim 3 wherein said 5
wires form said suspension means, said hemispherical
4
top having channels molded therein, said channels
being sized to receive said wires in an interference ?t,
said channels extending to an aperture in said top at said
apex, whereby said wires are press ?t into said channels
and extended through said aperture.
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