Note: Descriptions are shown in the official language in which they were submitted.
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Descri tion
Visual Brake Stroke Indicator
Field of Invention
This invention relates generally to a braking system, and in particular to a
visual
brake stroke indicator that may be easily installed on an air-brake chamber
and can determine
brake stroke condition without requiring the user to crawl under the vehicle.
Background Art
It is generally recognized that there is a need to be able to accurately
determine the
brake stroke condition on a vehicle's brakes, so as to ensure the timely
maintenance of the
vehicles' braking system. As most braking systems are difficult to inspect for
the brake
stroke condition, many operators of vehicles, such as trailers and trucks, let
the maintenance
of the brakes lapse which can result in a loss of brake effectiveness.
Prior art adjustment indicators have been devised to address the aforenoted
problems.
F'or example, United States Patent No. 4,279,214 issued July 21, 1981,
discloses a brake
adjustment indicator which can be installed on a vehicle with pneumatic
brakes. The
indicator includes a sleeve that loosely fits over the push rod of a pneumatic
actuator.
United States Patent No. 4,776,438 issued October 11, 1988, discloses a brake
adjustment indicator which includes a mounting bracket having an elongated
body with a slot
that runs parallel to a rod that extends through an air brake chamber and
connects at one end
to the brake arm by a clevis pin. United States Patent No. 4,879,964 issued
November 14, 1989, discloses an air brake
adjustment marker that includes an air supply, an air canister, and moveable
members that
include a push rod that extends from the air canister and has a first extended
position and a
second over-extended position. The adjustment marker includes a chain attached
to the push
rod, and an indicator flag that is activated when the push rod is in the over-
extended position.
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United States Patent No. 5,244,061 issued September 14, 1993, discloses an air
brake
stroke length gage that operates in conjunction with an air brake system. The
gage comprises
of a stroke length indicator that is mounted on the push rod, and a reference
marker that is
attached to the air brake system at a distance which corresponds to the
appropriate stroke
length for the brake system when properly adjusted.
United States Patent No. 5,320,198 issued June 14, 1994, discloses a indicator
for
indicating the setting and linear stroke movement of a brake rod of a brake
assembly. The
gage includes reference indicators that are located on both the brake rod's
clevis and on the
arm of the brake's slack adjustment member, thereby indicating the brake rod
travel and the
need for brake adjustment.
United States Patent No. 5,441,128 issued August 15, 1995, discloses a bracket
body
that can be attached to a brake rod and to the clevis inember of a
conventional brake
adjustment apparatus. The bracket body provides for an indirect nieasurement
of the brake
rod travel and adjustment.
Finally, Canadian patent application 2,186,271 which was laid open on November
2,
1996 shows the use of a brake adjustment indicator including a mounting
bracket, having an
elongated body with a slot, and a spacer for receiving two bolts for
indicating limit positions.
Disclosure of Invention
An object of one aspect of the present invention is to provide an improved
visual
brake stroke indicator. A further object of this invention provides an
improved visual brake
stroke indicator requiring fewer parts.
In accordance with one aspect of the present invention, there is provided a
visual
brake stroke indicator which is mounted on a chamber mounting bracket, outside
the brake
chamber and includes a clevis assembly with a modified clevis pin.
In accordance with still another aspect of the invention, there is provided a
visual
brake stroke indicator which comprises of a bracket that includes an elongated
member
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having at one end, an attachment portion at a right angle radius to the
elongated member.
The right angle radius reduces the stress on the elongated member. The
elongated member
may be tapered in shape, being wider at the end with the attachinent portion.
The elongated
member also includes of a continuous slot, a spacer plate with an attachment
means, and an
indicating means mounted at a predetermined distance from the clevis pin.
In accordance with a further aspect of the invention, there is provided a
visual brake
stroke indicator which may be easily installed in a short amount of time on
all types of cam
operated brake systems, and is relatively inexpensive but very durable.
Brief Description of Drawings
A detailed description of the preferred embodiment is provided herein below
with
reference to the following drawings, in which:
Fig. 1 is a perspective view of the visual brake stroke indicator, in
accordance with
the preferred embodiment of the present invention.
Fig. la is a top view of the clevis pin in accordance with the preferred
embodiment
of the present invention.
Fig. 2 is top view of the preferred embodiment in a first released position.
Fig. 3 is top view of the preferred embodiment in a second activated position.
Fig. 4 is top view of the preferred embodiment in a second activated position
requiring that the brakes need adjustment.
Fig. 5a is a top view of the bracket of the preferred embodiment of the
present
invention.
Fig. 5b is a front elevational view of the bracket of the preferred embodiment
of the
present invention.
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Fig. 5c is a top end view of the bracket of the preferred ernbodiment of the
present
invention.
Fig. 6a is a top view of the bracket of a second preferred embodiment of the
present
invention.
Fig. 6b is a front elevational view of the bracket of a second preferred
embodiment
of the present invention.
Fig. 6c is a top end view of the bracket of a second preferred embodiment of
the
present invention.
Figures 7a, b, c and d shown an alternate embodiment of a pointer than can be
used
in place of the clevis pin indicator.
In the drawings, preferred embodiments of the invention are illustrated by way
of
example. It is to be expressly understood that the description and drawings
are only for the
purpose of illustration and as an aid to understanding, and are not intended
as a definition
of the limits of the invention.
Best Mode for Caraing Out the Invention
In the description which follows, like parts are marked throughout the
specification
and the drawings with the same respective reference numerals. The drawings are
not
necessarily to scale and in some instances proportions may have been
exaggerated in order
to more clearly depict certain features of the invention.
Referring to Figure 1, there is illustrated in a perspective view, an
indicator 10 for
determining brake stroke condition on a vehicle braking system in accordance
with the
preferred embodiment of the present invention. The brake stroke indicator 10
for determining
brake stroke condition includes a bracket 12 having an elongated member 14
that has an
attachment portion 16 at one end 18. The elongated member 14 may occupy a
first plane that
is substantially perpendicular to a second plane occupied by the attachment
portion 16.
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Moreover, the attachment portion 16 is located at a right angle to the
elongated member 14.
A radius 20 is located between attachment portion 16 and elongated member 14.
The
attachment portion 16 has a hole 22 that allows the bracket 12 to 'be attached
to a chamber
mounting bracket 24 which supports a brake chamber 26. The brake chamber 26
has a clevis
assembly 28 that includes a clevis pin 30 that connects the clevis assembly 28
to a brake arm
29. The elongated member 14 may run parallel to the clevis assernbly 28, and
may have a
curve 31 at the mid-point of the elongated member so as to extend towards the
clevis
assembly 28 and specifically the clevis pin 30.
The elongated member 14 has a continuous slot 32 extending down the length of
the
elongated member 14. The continuous slot 32 may be of various lengths so as to
accommodate various brake systems such as on a bus. The elongated member 14
may also
be tapered in shape, generally being wider at the end 18 having the attachment
portion 16
which helps to reduce the vibrational forces along the elongated member 14
during the use
of the indicator 10. More specifically, since the attachment poi-tion 16 is
bolted to the
chamber mounting bracket 24, the elongated member 14 is free to vibrate as the
vehicle
nioves along the road. Therefore during use, stresses are localized along the
bend 33 and
eventually the bend 43 will break much like the repeated bending of metal.
These stresses
can be reduced by including the radius 20, reducing the ainount or weight of
metal from the
radius 20 by tapering the elongated member 14, and including the curve 31 at
the mid-point
of the elongated member 14.
A spacer plate 34 may be detachably mounted to the continuous slot 32 along
the
elongated member 14 by indicating means which also function as an attachment
means 36
to attach the spacer plate 34 to the elongated member 14. The attachment means
36
comprises two bolts or studs 43 and 45 which are thread through the continuous
slot 32 of
the elongated member 14 and two holes 47 and 49 of the spacer plate 34. Two
nuts 51 and
53 , and two locking washers 55 and 57 are provided. The bolts 43 and 45 also
function as
an indicating means, that is they indicate the two limit positions of'
acceptable brake travel.
However, in the preferred embodiment the indicating means 36 may be mounted on
the
spacer plate 34 by the attachment means 36 at a predetermined distance from
the clevis pin
30. The indicting means 36 in the preferred embodiment include yellow plastic
sleeves
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36 that fit over the bolts 43 and 45. The indicating means 36 define two
digits 39.
Moreover, since the bolts 43 and 45 fit through holes 47 and 49, the distance
between the
indicating means 36 (or digits 39) is set and may not accidentally move if
just a continuous
slot 32 were used without a spacer plate 34. The position of the indicating
means 38 define
the acceptable brake stroke travel between the digits 39, and thereby define
the degree of
wear of the brakes.
In operation,the indicator 10 for determining brake stroke condition can be
used to
quickly and efficiently determine the condition of the brake stroke on the
vehicle. How this
is achieved is explained here below with reference to Figures 1-4.The bracket
12 may be
mounted through the attachment portion 16, on the chamber mounting bracket 24
by a bolting
means 40, such as a stud 42 and nut 44. The chamber mounting bracket 24
supports the brake
chamber 26 which in turn supports the clevis assembly 28.The clevis assembly
28 extends
outwardly from the brake chamber 26 and the chamber mounting bracket 24, to be
connected
to the brake arm 29 by a clevis pin 30.
The elongated member 14 with the indicating means 36 secured to spacer plate
34,
may run parallel to the clevis assembly 28 such that when the brakes are in
the fully released
position, the clevis pin 30 sits at a predetermined distance from the
indicating means 38 or
plurality of digits 39, as for example shown in FIG.2. When the brakes of the
vehicle are
applied the clevis pin moves within the range of the two digits 39, thereby
determining that
the stroke on the brakes is still at an acceptable level, as shown for example
in FIG.3. When
the brakes are applied and the clevis pin 30 moves beyond the range of the two
digits 39, the
stroke on the brakes may be determined to be unacceptable and require
adjustment as shown
for example in FIG.4. The clevis pin can include a plastic sleeve 92
frictionally attached to
a reduction in the diameter 90 of the clevis pin which extends beyond the
large diameter of
the clevis pin 30.
Second Preferred Embodiment
Referring to Figures 6a, 6b and 6c, there is illustrated an indicator 10 for
determining
brake stroke condition on a vehicle braking system in accordance with the
second preferred
embodiment of the present invention. The brake stroke indicator 10 for
determining brake
stroke condition includes a bracket 12 having an elongated member 14 that has
an attachment
portion 16 at one end 18. The attachment portion 16 may generally lie along a
first plane
which may be substantially perpendicular to the elongated member 14 which may
generally
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lie along a second plane. A radius 20 is located between attachment portion 16
and
elongated member 14. The attachment portion 16 has a hole 22 that allows the
bracket 12
to be attached to a chamber mounting bracket 24 which supports a brake chamber
26. In a
preferred embodiment one hole 22 is provided and the centre line 75 of second
plane
occupied by the elongated member 14 passes through the confines of the hole
22, and more
preferably through its centre.
The indicator illustrated in Figures 6a, 6b and 6c may be stamped from a flat
sheet
of metal having the appropriate thickness. The stamped indicator would have
the elongated
member 14 and the attachtnent portion 16 in the same plane. Thereafter the
stamped
indicator would be bent so as to cause the elongated member to rotate or pivot
relative the
attachment portion by 90 degrees. In this way, the plane of the attachment
portion lies
generally substantially perpendicular to the elongated nlember 14.
Furthermore, the
elongated member 14 is bent so the plane of the elongated member 14 passes
through the
centre of hole 22. In this way one universal indicator 10 can be used on the
front, back, left
or right sides or the vehicle rather than using four separately configured
indicators, which
leads to a more complicated installation. The relationship of the plane of the
elongated
niember 14 passing through the hole 22 permits the use of one universal
indicator.
In another embodiment the bolts 43 and 45 may be replaced by single U-shaped
or
second bracket 59. The second bracket 59 may be detachably mounted to the
continuous slot
32 along the elongated member 14 by an attachment means 61. The second bracket
59 may
comprise of a base 60 and two members 62 extending vertically from the base
60. The
attachment means 61 may comprise of a single bolt 63 that is thread through
the continuous
slot 32 of the elongated member 14 and a hole 65 of the second bracket 59. A
nut 67 and
a locking washer 69 may be provided. The two vertically extending members 62
of the
second bracket 59 may be mounted on the continuous slot 32 at a predetermined
distance
from the clevis pin 30. The two vertically extending members 62 may further
comprise of
yellow plastic sleeves 42 so as to define digits 39. 'The base 60 may further
include an
abutment means 70 that may prevent the second bracket 59 from rotating around
the
continuous slot 32. The abutment means 70 may consist of' one or, as shown,
two punched
portions that are received into the slot 32 and bear against or abut along the
sides or confines
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of the slot so as to prevent relative movement of the second bracket 59 and
elongated
member 14 once it is fastened by the bolt 63. The use of a second bracket 59
provides
a simple one piece device that may be easily installed. The position of the
two vertically
extending members 62 to the clevis pin 30 may be indicative of the brake
stroke
condition on the vehicle braking system.
In summary a visual brake stroke indicator is provided with improved features
for
easy determination of brake stroke condition on a vehicle braking system.
Furthermore,
by using an attachment portion 16, which is at right angles to the elongated
member 14,
one indicator 10 may be used on the right side, left side or front or back of
the vehicle.
Various embodiments of the invention have now been described in detail. For
example, the clevis pin indicated or shown in Fig. 1 a may be replaced by a
pointer 90
as shown in Figs. 7a, b, c and d. The pointer 90 comprises of two parts 92 and
94
adapted to be clamped unto the push rod 29 but otherwise function similar to
the clevis
pin. The push rod 29 is adapted to be clamped between the two semicircular
sections
shown in Figure c and by bolts going through holes 95 (not shown). The usual
clevis
pin will be required to activate the braking mechanism through the push rod. A
plastic
sleeve similar to sleeve 42 may be added to extension 92.
The indicator for determining the brake stroke condition can comprise of a
bracket made from mild steel and plated with zinc.
Since changes in and/or additions to the above-described best mode may be
made without parting from the nature, spirit or scope of the invention, the
invention is
not to be limited to said details.