U.S. patent number 3,575,248 [Application Number 04/816,006] was granted by the patent office on 1971-04-20 for weighing device.
This patent grant is currently assigned to Westinghouse Air Brake Company. Invention is credited to Edward H. Bell.
United States Patent |
3,575,248 |
Bell |
April 20, 1971 |
WEIGHING DEVICE
Abstract
This invention relates to a weigh rail having a crown, a web, a
flange portion and an elongated slot extending transversely through
the web portion between the crown and flange portions. A
resiliently deformable means is interposed between the upper and
lower surfaces of the slot such that deflection of the crown
portion produces an orthogonal deflection of the resiliently
deformable means with respect to the deflection of the crown
portion. A transducing means is cooperatively associated with the
resiliently deformable means and is responsive to a deflection in
the resiliently deformable means for providing an indication which
is directly proportional to the amount of deflection of the crown
portion.
Inventors: |
Bell; Edward H. (Monongahela,
PA) |
Assignee: |
Westinghouse Air Brake Company
(Swissvale, PA)
|
Family
ID: |
25219423 |
Appl.
No.: |
04/816,006 |
Filed: |
April 14, 1969 |
Current U.S.
Class: |
177/163; 177/211;
177/208 |
Current CPC
Class: |
G01G
7/06 (20130101); G01G 19/042 (20130101); G01G
23/36 (20130101); G01G 3/08 (20130101); G01G
5/00 (20130101) |
Current International
Class: |
G01G
5/00 (20060101); G01G 7/00 (20060101); G01G
3/08 (20060101); G01G 23/18 (20060101); G01G
19/04 (20060101); G01G 3/00 (20060101); G01G
23/36 (20060101); G01G 19/02 (20060101); G01G
7/06 (20060101); G01g 003/12 (); G01g 019/04 () |
Field of
Search: |
;177/163,(Digest 8)/
;177/210,211,208,209 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,088,873 |
|
Oct 1967 |
|
GB |
|
797,161 |
|
Jun 1958 |
|
GB |
|
Primary Examiner: Ward, Jr.; Robert S.
Claims
I claim:
1. A weigh rail having a crown, a web and a flange portion, a slot
formed between said crown and flange portions and extending
transversely through said web portion, said slot having a
relatively long dimension disposed longitudinally along said rail,
a resiliently deformable means interposed between the upper and
lower surfaces of said slot, said resiliently deformable means
being deflected in conjunction with a deflection of said crown
portion of said rail such that the direction of motion of said
deflection of said resiliently deformable means is orthogonal to
the direction of motion of said deflection of said crown portion,
and a transducing means cooperatively associated with said
resiliently deformable means and responsive only to the orthogonal
deflection of said resiliently deformable means for providing an
indication of the amount of said deflection of said crown
portion.
2. A device for weighting objects moving over a section of track,
said track having an upper movable, an intermediate web, and a
lower stationary portion, a slot formed between said upper and
lower portions and extending transversely through said intermediate
portion, said slot having a relatively long dimension disposed
longitudinally along said section of track, a resiliently
deformable plate interposed between the upper and lower surfaces of
said slot, said resiliently deformable plate being deflected in
conjunction with a deflection of said upper movable portion of said
section of track, caused by the passing of said object, such that
the direction of motion of said deflection of said resiliently
deformable plate is orthogonal to the direction of motion of said
deflection of said upper movable portion, and a transducing means
cooperatively associated with said resiliently deformable plate and
responsive only to the orthogonal deflection of said resiliently
deformable plate for providing an indication of the amount of said
deflection of said upper movable portion according to the weight of
said object.
3. The weigh rail of claim 1 wherein said transducing means
comprises a bank of electrical contacts in vertically staggered
alignment with said resiliently deformable means, the closing of
any one of said electrical contacts dependent upon the amount of
deflection of said resiliently deformable means due to the amount
of deflection of said crown portion of said rail.
4. The weigh rail of claim 2 wherein said resiliently deformable
means is a metal plate and said transducing means is a static metal
plate in such alignment with said resiliently deformable means as
to form a variable capacitive device, the capacitance of said
variable capacitive device varying according to the amount of
distance between said resiliently deformable means and said static
plate, said distance varying according to the amount of deflection
of said resiliently deformable means.
5. The weigh rail of claim 1 wherein said transducing means is a
plurality of back pressure switches, each of said switches having
at least one input conduit, and first and second output conduits
and a control conduit, said control conduits in vertically
staggered alignment with said resiliently deformable means, said
supply input providing a continuous flow of fluid at a
predetermined pressure such that whenever said control conduit is
free from obstruction by said resiliently deformable means, there
will be an indication at said first output conduit, and whenever
said control conduit is obstructed by said resiliently deformable
means there will be an indication at said second output conduit,
and the obstructing of any one of said control conduits dependent
upon the amount of deflection of said resiliently deformable means
due to the amount of deflection of said crown portion of said
rail.
6. The weigh rail of claim 1 wherein said transducing means is a
back pressure sensing device having an input conduit, and first and
second output conduits, said input conduit providing a continuous
flow of fluid at a predetermined pressure, said first output
conduit and said resiliently deformable means initially separated,
at zero deflection of said resiliently deformable means, by a
predetermined distance such that a zero deflection of said first
output conduit will allow a maximum flow of fluid and no fluid flow
from said second output conduit and as said predetermined distance
decreases due to deflection of said resiliently deformable means,
said first output conduit will decreasingly allow fluid to flow
therefrom while said second output conduit will increasingly allow
air to flow therefrom.
7. The weigh rail of claim 1 wherein said transducing means is a
variable resistance such that the deflection of said resiliently
deformable means causes a proportional change in said variable
resistance.
8. The weigh rail of claim 1 wherein the amount of deflection of
said resiliently deformable means at its center, due to the amount
of deflection of said crown portion of said rail is given by the
equation,
where: Z.sub.DEF = deflection of said resiliently deformable means
at its center
Y.sub.STRN = downward deflection of said crown portion of said
rail
and: Y.sub.SPAN = height of said slot at zero deflection.
9. The weigh rail of claim 1 wherein said transducing means is an
analogue device.
10. The weigh rail of claim 1 wherein said transducing means is a
digital device.
Description
My invention relates to a weight rail.
More specifically, my invention relates to a weight rail having a
crown, a web, a flange portion and a slot formed between the crown
and flange portions. The slot extends transversely through the web
portion and has a relatively long dimension disposed longitudinally
along the rail. A resiliently deformable means is interposed
between the upper and lower surfaces of the slot. This resiliently
deformable means is deflected in conjunction with a deflection of
the crown portion of the rail. The resiliently deformable means is
deflected orthogonal to the direction of motion of the deflection
of the crown portion by a passing railway vehicle. A transducing
means is cooperatively associated with the resiliently deformable
means and is responsive to the orthogonal deflection of the
resiliently deformable means for providing an indication which is
directly proportional to the amount of the deflection of the crown
portion of the rail, and, in turn, the weight of the passing
railway vehicle.
In the past, weight rails for measuring the weights of railway
vehicles employed various lever arrangements, such as, those shown
in U.S. Pat. Nos. 2,902,595 and 2,487,613 for transducing or
converting rail deflection into an effective indication of vehicle
weight. It will be noted that these previous arrangements include a
primary as well as a secondary lever each of which is pivotally
moved in response to the deflection of the weight rail. The pivotal
movement of the secondary lever is employed to control a
transducing means. It will be further noted that the primary lever
is interposed within a slot longitudinally displaced along the
rail; and is arranged to have one end mechanically contact the down
portion of the rail. This primary lever is pivoted about a suitable
bearing or fulcrum point which is rigidly fixed to provide
rotational movement and to prevent translational movement. The
other end of the primary lever is arranged to cooperate with an
adjustment screw carried by one end of the secondary lever. The
secondary lever is also pivoted on a suitable bearing or fulcrum
point similar to the primary lever fulcrum point. The opposite end
of the secondary lever is cooperatively associative with
appropriate transducing means such as a bank of movable and
stationary contacts. Accordingly, any downward deflection in the
crown portion of the weigh rail causes a corresponding downward
movement of the one end of the primary lever. This causes the
opposite end of the primary lever, and, in turn, the adjustable end
of the secondary lever to move upwardly. This upward movement
causes the other end of the secondary lever to move downwardly. The
bank of contacts are arranged such that they are successively
closed in weight responsive sequential order depending upon the
weight of a railway vehicle on the weigh rail. That is, a
lightweight vehicle will only result in the closing of a single
contact of the bank of contacts transducing means while a
mediumweight vehicle will result in the closing of a pair of
contacts and so on.
However, there are several disadvantages and certain undesirable
features incorporated in the above-noted types of prior art weight
rail arrangements which contribute to the need for a more desirable
type of weight rail. First, in previous weigh rails, the maximum
obtainable ratio between downward movement of the contact operating
end of the secondary lever and the downward deflection of the crown
portion of the rail itself is in the order of only 10 to 1. It will
be appreciated that such a ratio is small so that there is little,
if any, latitude in the adjustment of the adjusting screws. Second,
the large number of moving parts required in previous weigh rails
increases the amount of mechanical wear and results in repeated
maintenance and repair problems. Third, the prior art types of
weigh rails are also initially relatively expensive. Fourth, since
the bank of contacts move in a vertical movement, the vibrational
effects upon the operation of the weight rail result in erroneous
weight indications. Thus, it will be appreciated that a new and
improved weigh rail free of the above-mentioned disadvantages is
desirable for more efficient railway operation.
It is therefore an object of this invention to provide a novel
weight rail for measuring various degrees of vehicular weight with
greater weight sensitivity and lesser adjustment requirements.
Another object of this invention is to provide an improved weigh
rail with fewer moving parts so that it is less susceptible to
mechanical wear.
Yet another object of this invention is to provide a new and
improved weigh rail which is more economic in construction as well
as in maintenance.
Still another object of this invention is to provide a novel weigh
rail which is less affected by environmental vibrations and other
adverse conditions.
Yet still another object of this invention is to provide an
improved weigh rail which is compact.
A further object of this invention is to provide a new and improved
weigh rail which measures varying degrees of vehicular weight by
the employment of a rail having a crown, a web, a flange portion,
and a slot longitudinally disposed through the web portion and
having a resiliently deformable means interposed between its upper
and lower surfaces and a transducing means responsive to the
deflection of the resiliently deformable means for indicating the
weight of a railway vehicle.
In the attainment of the foregoing objects, the present invention
employs a weigh rail for weighing a railway vehicle as it moves
through a section of track. The weigh rail includes conventional
crown, web, and flange portions and is provided with an elongated
slot disposed between the crown and flange portions. The slot
extends transversely through the web portion and has a relatively
long dimension coincident with the length of the rail. A
resiliently deformable means, preferably in the form of a metallic
or synthetic plate, is interposed between the upper and lower
surfaces in the slot. This resiliently deformable plate is
deflected in conjunction with a deflection in the crown portion of
the rail caused by a passing railway vehicle. The direction of
motion of the deflection of the resiliently deformable plate which
is orthogonal to the direction of motion of the deflection of the
crown portion of rail is employed to control a transducing means.
The transducing means may consist of a bank of contacts, a
plurality of digital back pressure switches, an analogue back
pressure sensor, a variable capacitive device, or a rheostat.
Accordingly, the transducing means is controlled in accordance with
the amount of orthogonal movement of the resiliently deformable
plate for providing an indication which is proportional to the
weight of the vehicle passing over the rail.
Other objects an advantages of the present invention will become
apparent from the ensuring description of various illustrative
embodiments thereof, in the course of which reference is had to the
accompanying drawings in which:
FIG. 1 illustrates a vehicle wheel passing over a rail section
which has an elongated slot formed in its web portion.
FIG. 2 depicts a sectional side view of the rail section of FIG. 1
with the above described resiliently deformable plate interposed
between the upper and lower surfaces of the slot.
FIGS. 2A and 2B illustrate geometric figures which aid in providing
a mathematical description of the lateral deflection of the
resiliently deformable plate of FIG. 2.
FIG. 3 illustrates one embodiment of a weigh rail of the present
invention wherein the transducing means comprises a plurality or
bank of electrical contacts.
FIG. 3A shows a front view, with portions removed, of the
embodiment of the weigh rail of the present invention of FIG.
3.
FIG. 4 depicts another embodiment of a weigh rail of the present
invention wherein the resiliently deformable means is a dynamic
metal plate and the transducing means is a static metal plate.
FIG. 5 illustrates yet another embodiment of a weigh rail of the
present invention wherein the transducing means is a fluidic back
pressure sensor.
FIG. 6 depicts still yet another embodiment of a weigh rail of the
present invention wherein the transducing means is a plurality of
fluidic back pressure switches.
FIG. 6A shows a front view with portions removed of the embodiment
of the weigh rail of the present invention of FIG. 6.
FIG. 7 illustrates another embodiment of a weigh rail of the
present invention wherein the transducing means is a variable
resistance.
A description of the above embodiments will follow and then the
novel features of the invention will appear in the appended
claims.
Reference is now made to the drawings and, particularly to FIG. 1,
which shows a railway vehicle wheel 11 rotatably secured on axle 12
passing over a weigh rail section 13. The weigh rail section 13
consists of a running crown portion 14, a web portion 15, and a
supporting flange portion 16 appropriately secured to conventional
ties (not shown) in the usual manner. A slot 17 is formed in the
weigh rail 13 and extends transversely through the web portion 15.
The slot 17 is shown having a relatively long dimension
longitudinally along the length of the weigh rail section 13. The
elongated slot 17 includes a movable upper surface 17a, and a
stationary lower surface 17b. Accordingly, whenever the wheel 11 of
a railway vehicle passes over the slot 17, the upper crown portion
14 of rail section 13 will be deflected from a normal position as
shown by dotted line 14a to a deformed position as shown by solid
line 14b. The amount of deflection of the crown portion 14 of rail
section 13 will, of course, vary with the weight of each passing
railway vehicle. The deflection of the upper crown portion 14 of
rail section 13 will cause a corresponding or proportional amount
of deflection to occur in the upper surface 17a of the slot 17, as
shown by the solid outline 17a'.
Referring now to FIG. 2 there is depicted a cross-sectional view of
the weigh rail 13 of FIG. 1 with a resiliently deformable plate 21
interposed between the upper and lower surfaces 17a and 17b. As
shown, the upper and lower extremities or edges of deformable plate
21 are positioned within a pair of milled grooves 18a and 18b,
respectively. It is desirous that the resiliently deformable plate
21 be initially prestressed and slightly tensed to prevent slipping
and dislodgement from the slot 17. Accordingly, when a vehicle
wheel passes over the crown portion 14 of rail section 13, the
crown portion 14 will flex and in turn cause a proportional amount
of deflection in the upper surface 17a of slot 17 to bring the
upper surface 17a to a position shown by the solid line 17a' as
shown in FIG. 2. Hence, the resiliently deformable plate 21 will
move and bend from its original position at "no load" shown by
dotted outline 21a to the position shown in solid outline 21b in
FIG. 2. For the purpose of discussion, the vertical amount of
downward deflection of crown portion 14 of rail section 13 is
designated as Y.sub.STRN, and the amount of deflection of the
center of the resiliently deformable plate 21 is designated as
Z.sub.DEF. The original height or vertical dimension of the slot at
"no load" in which the resiliently deformable plate 21 is
positioned is designated as Y.sub.SPAN.
In viewing FIGS. 2A and 2B, it will be noted that the geometric
figures are employed for illustrating and analyzing the
mathematical calculation of the horizontal deflection at the center
of resiliently deformable plate 21 of FIG. 2. For example, FIG. 2A
shows a circular diagram 19 having a chord L subtending an arc of
length S two lines of length L' extending from the end points of
chord L to the midpoint of arc S. Thus, an isosceles triangle is
formed by sides L' and chord L which has a height D. The arc S is
analogous to the resiliently deformable plate 21 in its deflected
position. It will be appreciated that since the height of the
resiliently deformable plate 21 at "no load" is approximately equal
to the height of the slot 17 at "no load," then S=Y.sub.SPAN The
chord L is analogous to the difference between the height of the
slot 17 at "no load," Y.sub.SPAN, and the amount of downward
vertical deflection of the upper surface 17a of the slot 17 between
an unloaded and loaded weigh rail of FIG. 2, Y.sub.STRN.
More simply, L=Y.sub.SPAN -Y.sub.STRN =S-Y.sub.STRN.
By Huygens' approximation formula, it is found that:
But, as noted above, L=S-Y.sub.STRN, or S=L+Y.sub.STRN, and
substituting this relationship into equation (1) we have:
But, also as noted above L=Y.sub.SPAN -Y.sub.STRN, and substituting
this relationship into equation (2) we have:
or
3 Y.sub.SPAN =8 L' -Y.sub.SPAN +Y.sub.STRN eq. (4).
Now, solving for L', we have:
8 L' =4Y.sub.SPAN -Y.sub.STRN eq. (5),
or
L'=1/2 Y.sub.SPAN -1/8 Y.sub.STRN eq. (6).
Referring to one of the right triangles in FIG. 2A, which has been
shown separately and enlarged in FIG. 2B and employing the
Pythagorean Theorem for Right Triangles (c.sup.2 =a.sup. 2
+b.sup.2), it will be seen that we obtain
(L').sup.2 +(L/2).sup.2 +D.sup.2 eq. (7.
Since D is equal to the deflection of the center of the resiliently
deformable plate 21, Z.sub.DEF, we can substitute Z.sub.DEF for D
in equation (7) and by transposing we have:
(Z.sub.DEF).sup. 2 =(L' ).sup.2 -(L/2 ).sup.2 eq. (8),
Remembering that L' =1/2 Y.sub.SPAN -1/8 Y.sub.STRN and that
L=Y.sub. SPAN -Y.sub.STRN, equation (8) then becomes:
(Z.sub.DEF .sup. 2 +(1/2 Y.sub.SPAN -1/8 Y.sub.STRN).sup.2
-(Y.sub.SPAN -Y.sub.STRN).sup. 2 eq. (9),
or
(Z.sub.DEF) .sup.2 =1/4 (Y.sub.SPAN).sup.2 1/8 Y.sub.SPAN
Y.sub.STRN +1/64 (Y.sub.STRN).sup. 2 1/4 (Y.sub.SPAN .sup.2 +1/2
Y.sub.SPAN Y.sub.STRN -1/4 (Y.sub.STRN).sup.2 eq. (10)
or
(Z.sub.DEF).sup.2 =3/8 Y.sub.SPAN Y.sub.STRN -15/64
(Y.sub.STRN).sup.2 eq. (11),
or
Solving for Z.sub.DEF we have,
As an example, let us suppose the Y.sub.SPAN =2.0" and that the
weight of a given wheel 11 causes the weigh rail 13 to deflect from
its original position, such that Y.sub.STRN =0.00010 inches. As
seen by substituting these values into equation (13), we have
or
Z.sub.DEF =0.00866 inches.
Now taking the ratio of Z.sub.DEF (deflection of the center of the
resiliently deformable plate 21) and Y.sub.STRN (vertical amount of
downward deflection of crown portion 14), we find
Thus, it can be seen that a very small crown portion deflection
results in a relatively large deflection at the center of the
resiliently deformable plate which is highly advantageous achieving
greater weight sensitivity then heretofore possible.
Reference is now made to FIGS. 3 through 7 which depict several
different embodiments of the present invention in which the
aforementioned transducing means may be incorporated either as an
analogue device or as a digital device.
Turning to FIGS. 3 and 3A, it is noted that FIG. 3 illustrates the
weigh rail of the present invention employing a plurality or bank
of associated movable and stationary electrical contacts. While it
will be noted that a bank of three contacts 20, 25 and 30 is shown
in FIG. 3, it will be understood that a greater or lesser number of
contacts may be utilized in practicing this invention. In order to
protect the resiliently deformable plate 21, and the transducing
means from dust, dirt and other adverse conditions, it is
advantageous to fully enclose slot 17. A first cover 36 in FIG. 3A,
is shown secured by bolts 37 and 38 to the outer side of the weigh
rail 13 and a second cover 33 and weather tight seal member 42 are
securely held in place by screws 34 and 35. It will be noted that
the covers 36 and 33 and the seal member 42 are appropriately
mounted such that they do not impair the downward deflection of the
crown portion 14 of weigh rail 13.
As previously mentioned, there is a bank of three normally open
contact pairs 20, 25 and 30 each of which is vertically displaced
or staggered with respect to one another. As shown, each of the
three contacts comprises a movable contact element 23 and a
stationary contact element 24. Each of the resiliently movable
contact springs 23 and the stationary contact springs 24 are shown
held in insulative relationship by means 28a and 28b respectively
to the inner and outer insulating blocks 26 and 27 which, in turn,
are secured to the flange portion 16 by means of bolts 29. It will
be noted that a pair of suitable wires or leads 31 and 32 are
electrically coupled to the movable and stationary contact elements
of each of the three contact pairs. It will be appreciated that the
leads 31 and 32 may be appropriately connected to any suitable
supervisory apparatus, such as, an automatic retarder contacting
system in classification yards. As mentioned, the three contact
pairs 20, 25 and 30 are vertically positioned relative to each
other so that a different level of displacement of the resiliently
deformable means 21 is required to close each contact pair.
Accordingly, such an arrangement provides a digital method of
determining various weights of vehicles being processed. That is,
with the maximum deflection of the resiliently deformable plate 21
occurring at its center, and with the deflection of the resiliently
deformable plate 21 geometrically decreasing on either side of its
center dependent upon the point selected, the three contact pairs
20, 25 and 30 will be additively closed upon the vehicle
weight.
Each of the contact elements is formed of suitable resilient
conductive material, such as beryllium copper, and includes a first
vertical supporting portion, a horizontal intermediate portion and
a second vertical contact portion. The second vertical portion of
each movable contact element also includes a contiguous abutment in
the form of a hook or turned over portion for cooperating with the
resiliently deformable plate 21. In the present arrangement, a
"lightweight" vehicle will only cause contact pair 20 to be closed,
a "mediumweight" vehicle will cause both contact pairs 20 and 25 to
close and a "heavyweight" vehicle will cause all three contact
pairs 20, 25 and 30 to close. As previously mentioned, a contact
arrangement employing a greater number of contact pairs will
produce a greater number of weight classes thereby achieving a
greater degree of weighing accuracy.
Referring now to FIG. 4, there is illustrated another embodiment of
the invention which utilizes a flat metal plate 41 in place of the
bank of three contact pairs. The metallic plate 41 is preferably
constructed of suitable conductive material, such as aluminum or
copper and is positioned in spaced relationship with the
resiliently deformable metallic plate 21. As in the embodiment
shown in FIG. 3A, the metallic plate 41 is insulated from the weigh
rail section by inner and outer insulating blocks 26a and 27a. The
insulative blocks 26a and 27a are securely fastened to the flange
portion 16 by suitable bolts, only one of which is shown at 29a. A
first lead-in wire 31a is directly coupled to the metallic plate 41
through a bolt 28a which rigidly secures the metallic plate 41
between the insulative blocks 26a and 27a while a second lead-in
wire 32a is connected to bolt 28b. In this embodiment the bolt 28b
passes completely through the insulative blocks 26a and 27a as well
as through member 42 and thereby engages the flange portion 16.
Thus, the lead wire 32a is conductively connected through bolt 28b
and flange portion 16 to the resiliently deformable metallic plate
21. The remainings, such as, the protective coverings for the slot
17 are the same as those described in the previous weigh rails. As
in the weigh rail of FIG. 3, whenever a vehicle wheel moves on to
the crown portion 14 of rail section 13 shown in FIG. 4, the crown
portion 14 will deflect causing a proportional amount of deflection
of the resiliently deformable metallic plate 21. Thus, it can be
seen that the spacing between the resiliently deformable metallic
plate 21 and the metallic plate 41 will decrease from the original
positions as shown in FIG. 4. It will be appreciated that the
spacing will vary in accordance with the weight of the vehicle.
Thus, it will further be appreciated that the plates 21 and 41 may
be employed as a capacitor. That is, since the capacitance value is
dependent upon the spacing between plates 21 and 41, and, in turn,
upon the amount of deflection of the deformable plate 21, an
analogue indication of vehicle weight may be measured by connected
leads 31a and 32a to a capacitance bridge or the like.
Reference is now made to FIG. 5 which illustrates another
embodiment of a weigh rail in accordance with the present
invention. As shown, the transducing means now takes the form of a
fluidic back pressure sensor 46. The fluidic back pressure sensor
46 may be of the type manufactured by Pitney-Bowes, and listed as
Pat No. 6,080,008 which includes a single input and a pair of
outputs. A supply of air at a predetermined pressure is normally
delivered to the back pressure sensor 46 via input conduit 47. When
the discharge hole of output conduit 48 is unobstructed as shown in
FIG. 5, the air supplied to the input conduit 47 will all flow
through the discharge hole. However, when an obstacle partially or
completely blocks the discharge hole the supply of air will be
"backed-up" or diverted and will begin flowing through output
conduit 49 of back pressure sensor 46. The amount or pressure of
air flowing through output conduit 49 can therefore be used as an
analogue indication of the nearness of an obstacle to the discharge
hole of conduit 48. Thus, by employing the deformable plate 21 as
the discharge controlling obstacle, the weight of a vehicle on rail
section 13 can be accurately measured in accordance with the amount
of deflection of the resiliently deformable plate 21. In this case,
the greater the vehicle weight, the greater will be the deflection
of the resiliently deformable plate 21, and, therefore, the amount
of air through output conduit 48 will be smaller while the degree
of "back pressure" through the output conduit 48, and the amount of
air and pressure through output conduit 49 will be greater. As
shown, back pressure sensor 46 is rigidly held in alignment with
the resiliently deformable plate 21. The sensor 46 includes a
suitable arm or bracket 50 which is interposed between a pair of
shock absorbent mounting blocks 26b and 27b which, in turn, are
held in place by bolts 29b and 29c. The remaining elements such as
the covers for the slot 17 of this embodiment are substantially the
same as described above. It should be understood that while an air
supply is used in conjunction with the back pressure sensor 46,
other available fluids and supply sources may equally well be
employed without impeding weigh rail accuracy.
Turning now to FIGS. 6 and 6A, there is shown a fluidic digital
version of a weight rail similar to FIGS. 3 and 3A in which the
transducing means takes the form of a plurality of individual
fluidic back pressure switches. It will be noted in view of FIG. 6A
that a plurality of back pressure switches 63, 64 and 65 are
disposed longitudinally along rail 13. The switch 63 is disposed in
alignment with the longitudinal centerline of the resiliently
deformable plate 21 while the remaining two switches 64 and 65 are
disposed at some point below the centerline. Each of the back
pressure switches 63, 64 and 65 includes an input conduit, a pair
of output conduits and a control conduit. As shown, the back
pressure switches are carried by separate bracket 56 which is
resiliently mounted to the flange portion 16 by means of an inner
and an outer shock absorbent mounting block 57 and 58 through which
a plurality of bolts 59 and 60 pass and securely hold switches 63,
64 and 65 in proper relationship with deformable plate 21. A supply
of air is normally delivered to the back of each pressure switch
via input conduits 52. Normally, whenever a control conduit 53 is
totally blocked or obstructed, air will no longer flow through
output conduit 54 but will flow through output conduit 55. That is,
when the resiliently deformable plate 21 is in the position as
shown in FIG. 6, air pressure is available on all of output
conduits 54, and none of the control conduits 53 is obstructed by
the resiliently deformable plate 21. Now when a "lightweight"
vehicle passes onto weigh rail 13, the deformable plate is arranged
to obstruct the control conduit 53 of switch 63 so that air
pressure mediumweight" switched from output conduit 54 to output
conduit 55. Since the resilient deformable plate 21 will deflect
more and more further outwardly under increasing loads, the back
pressure switches 64 and 65 are arranged to assume their
obstructing or blocking positions of the control conduits 53 under
medium and heavyweight cars. respectively. Hence, the plurality of
back pressure switches 63, 64 and 65 cooperate with the resiliently
deformable plate 21 to provide a digital method of determining
three levels of vehicle weight, similar to the electrical contact
arrangement of FIGS. 3 and 3A. While FIG. 6A depicts only three
back pressure switches vertically displaced at and below the
centerline of resiliently deformable plate 21 to indicate
"lightweight," "mediumweight" and "heavyweight" vehicles, it will
be understood that a greater or lesser number of back pressure
switches may be used in practice in this invention. Further, it
should be noted that the back pressure switches may be disposed
above the centerline with the same results and achieve a greater
degree of weighing accuracy. It has been found that a suitable type
of back pressure switch may be of the type manufactured by Corning
Fluidic Products Division described in Catalog No. 191,473.
FIG. 7 shows another embodiment of my invention in which the
transducing means is a variable resistor or rheostat 67. As shown,
C-shaped operating cam 68 is interposed between the resiliently
deformable plate 21 and the variable resistor 67. The C-shaped cam
68 intimately contacts the resiliently deformable plate 21 and is
mechanically coupled to a rotatable shaft 81 which varies the
resistance of resistor 67. The variable resistor 67 is secured to
one end of a suitable bracket 69, the other end of which is held
between inner and outer resilient mounting blocks 72 and 73. A pair
of bolts 74 and 76 is secured to the mounting blocks 72 and 73 and
also the other end of bracket 69 to the flange portion 16 of rail
section 13. Now whenever a wheel passes over rail section 13 and
particularly over slot 17, the resiliently deformable plate 21 will
cause the C-shaped cam 68 to rotate about the shaft 81 so that the
change in resistance of the variable resistor 67 is proportional to
the weight of the passing vehicle. The resistance change of the
variable resistor 67 provides an analogue indication of the weight
of the railway vehicles. This resistance change may be readily
measured by any suitable means, such as an ohmmeter which can be
easily connected to leads 78 and 79.
As previously mentioned, it will be noted that the plurality of
contact pairs of FIGS. 3 and 3A and the plurality of back pressure
switches of FIGS. 6 and 6A provide digital indications of vehicle
weight, while the variable capacitive arrangement of FIG. 4, the
back pressure sensor arrangement of FIG. 5 and the variable
resistor arrangement of FIG. 7 provides analogue indications of
vehicle weight. Further, it will be noted that any suitable
conversion means for converting the electrical and fluidic
indications into useable data for automatic classification yard
operations may be employed with my invention.
Thus, it is apparent that the new and improved weigh rail
arrangements of the present invention provide a more effective and
mechanically unique method for measuring weights of vehicles which
is inexpensive, compact, and more sensitive to weight changes.
* * * * *