Abstrict A flow meter for measuring the consumption of a fluid such as tap
water and indicating it digitally at a remote place from the detecting
section, having a pulse generator; means for giving intermittent
rotation to the rotor of the generator which comprises a cam plate
with a dwell portion of the same radius and a plurality of recesses
formed at the outer periphery thereof, a driving disc placed coaxially
therewith and capable of rotating relatively to the cam plate within
a prescribed angle, and an intermittently-driven member provided
with a plurality of projections capable of being engaged with said
recesses at the outer periphery thereof correspondingly to the cam
plate and connected to the rotor shaft of the pulse generator; and
a pulse motor capable of operating the indicating wheels by using
the pulse voltage from the pulse generator.
Claims What we claim is:
1. A flow meter comprising a flow-rate detecting means for dynamically
converting the flow rate of a fluid to be measured into a continuous
rotation, thereby continuously rotating an output member; an intermittent-movement
conversion means including a reduction gear mechanism and arranged
close to said detecting means so as to rotate an output member of
the conversion means rapidly and intermittently each time the rotation
of an input member of the conversion means continuously rotating
in response to the rotation of the output member of said detecting
means attains a prescribed degree; a pulse generator including a
rotor rapidly rotatively driven by the output member of said conversion
means and a generation coil generating driving pulses in response
to the intermittent rotation of the output member of said conversion
means and arranged close to said conversion means; and an indicating
device for digitally indicating the consumption of a fluid, having
a counting means including a series of indicating wheels and an
electrical-mechanical conversion means for operating said counting
means by means of driving pulses from said pulse generator and arranged
at a remote place from said pulse generator; said intermittent-movement
conversion means comprising a driving disc capable of continuously
rotating at a speed reduced by means of said reduction gear mechanism
in accordance with the rotation of the input member, a cam plate
capable of rotating relatively to and coaxially with said driving
disc through a prescribed angular range, said cam plate having a
dwell portion and a plurality of cam grooves formed on the outer
periphery thereof, said dwell portion having the same radius as
said cam grooves, a spring drum rotating about an axle parallel
to that of said driving disc, an intermittently-driven member arranged
rotatably on the same axle as that of said drum, forced to rotate
only in one direction in accordance with the rotation of said spring
drum, and having a plurality of projections capable of being engaged
with the cam grooves of said cam plate; said driven member being
restrained by the dwell portion of said cam plate from rotating
in opposition to the biasing force of said spring drum with the
projections thereof not corresponding to the cam grooves of said
cam plate, and rotated rapidly through a prescribed angular range
by the biasing force of said spring drum with the projections thereof
corresponding to the cam grooves in accordance with the rotation
of the cam plate, thereby providing an intermittent rotary drive
of the output member of said intermittent-movement conversion means;
said electrical-mechanical conversion means including a pulse motor.
2. A flow meter according to claim 1 wherein said driving disc
has an arcuate recess peripherally notched through a prescribed
angle on the outer periphery thereof, said cam plate has a pin laterally
protruding on one side thereof and penetrating into said arcuate
recess, and the relative angle of rotation between the driving disc
and the cam plate is defined by said pin and arcuate recess.
3. A flow meter according to claim 1 wherein the cam grooves of
said cam plate are formed into a diametrically opposite pair, and
the projections of said intermittently-driven member are four in
number and so arranged as to provide an angle of 90.degree. between
each two adjacent ones about the center.
4. A flow meter according to claim 1 wherein said intermittent-movement
conversion means and said pulse generator are contained in a substantially
cylindrical casing, said casing being removably mounted on said
flow-rate detecting means as a single unit.
Description This invention relates to a flow meter capable of digitally indicating
the consumption of a fluid at a remote place from the detecting
section by means of a pulse generator without using any dry cells
or commercial power sources.
The flow meter, provided with such a pulse generator, has no such
various drawbacks that may be encountered in those with commercial
power sources or dry cells. In a flow meter using a commercial power
source, for instance, the switch may not fully be actuated or the
contacts may be subject to burning, while, in a meter using a dry
cell, additional personal expenses may be required for periodically
replacing the dry cell and there are problems of the safety of the
meter and of the elimination or reduction of labor for the maintenance
and inspection thereof. The flow meters provided with pulse generators,
however, have eliminated all these problems. Accordingly, such flow
meters have widely been used of late.
Conventional flow meters using such a pulse generator include,
for instance, those presented in U.S. Pat. No. 3555902. However,
such kind of flow meters in the prior art including the above patent
required to be further improved in some points; a magnetic count
indicating mechanism has generally been employed in the section
for digitally indicating the consumption of a fluid by utilizing
the electrically pulses from the pulse generator. Therefore, the
generator is required to be relatively large in size, necessitating
a large-sized intermittent-movement conversion means for driving
the magnetic core by converting the rotation energy from the detecting
section into the intermittent rotation energy in order to give sufficient
power to the rotary drive of the magnetic core of the generator.
In this kind of conventional flow meter of this kind, as illustrated
in FIGS. 2 and 3 of the aforementioned U.S. Pat. No. 3555902
the intermittent-movement conversion means includes a continuously
rotating cam member and a lever which engages with the cam member
and rapidly reciprocatively rocks through a prescribed angle in
accordance with the rotation of the cam member, being so constructed
that the generator may be driven by the reciprocative rocking action
of the lever. In such construction, however, it is impossible to
minimize substantially the interval between the axles of the lever
and the cam member, so that it has been difficult to miniaturize
the intermittent-movement conversion means.
An object of this invention is to provide a flow meter with a pulse
generator which is made compact as a whole, capable of operating
with less energy, low in manufacturing cost, and reliable in operating.
SUMMARY OF THE INVENTION
In order to attain this object, the present invention is characterized
by providing a pulse motor placed between the indicating means for
digitally indicating the consumption of a fluid and the generator,
and a cam plate having a dwell portion of the same radius and cam
grooves at the periphery thereof, and an intermittently-driven member
having a plural number of projections capable of engaging the cam
grooves of the cam plate.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention can be more fully understood from the following
detailed description when taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is a partially broken side view of an embodiment of the
flow meter of this invention, in which the part including the detecting
section and the pulse generator is exposed;
FIG. 2 is a top view on a reduced scale of the same flow meter
as that of FIG. 1;
FIG. 3 is a diagrammatical side view of a flow meter according
to the present invention; and
FIGS. 4 to 6 are diagrams viewed along line A--A of FIG. 3 in which
the operative relationship between the cam plate and the intermittently-driven
member of the flow meter according to the present invention is illustrated
.
DETAILED DESCRIPTION
Referring now to FIG. 1 there is shown a flow meter of the invention
suitable for measuring the consumption of tap water, wherein a water-proof
detecting device 10 is connected to a water main pipe 11. The device
10 may be selected from well known those including those provided
with runners (not shown) rotated by the flow of tap water. This
device 10 dynamically converts the flow rate of a fluid into continuous
rotation and transmits it to an output member 12. A substantially
cylindrical plastic casing 13 is removably mounted on the device
10 with a male screw portion 13a formed at the bottom of the casing
screwed into a female screw portion 10a formed on the device 10.
A plastic frame 14 is supported at the lower half region within
the casing 13 and a pulse generator 15 is placed in the upper half
region. The frame 14 consists of an upper plate portion 14a substantially
at the center of the casing 13 a lower plate portion 14b at the
lower portion, and a plurality of vertical leg portions 14c (only
one shown in the figure) interconnecting both these plate portions.
Between these upper and lower plate portions 14a, 14b are supported
5 axles or shafts 16 17 18 19 and 20 running parallel to one
another in a vertical direction as shown in FIG. 3. The lower plate
portion 14b supports a magnetic disc 21 as an input member, which
corresponds to another magnetic disc 22 fixed on the output member
12 of the detecting device 10. Both magnetic discs 21 22 constitutes
a magnetic coupling, which is so constructed that the input member
21 is rotated in accordance with the rotation of the output member
12.
The said pulse generator 15 comprising a rotary shaft 23 a gear
24 fixed to the bottom thereof, a rotor 25 fixed to the same rotary
shaft 23 a generation coil 26 an iron core 27 and a cap member
28 covering the aforementioned components, is made compact in the
aggregate.
In FIG. 3 said pulse generator 15 is electrically connected to
an indicating device 30 at a remote place by lead wires 31. The
indicating device 30 is provided with a counting means composed
of a series of indicating wheels 32 said counting means connected
to a pulse motor 34 as a means for electrical-mechanical convertion
through an intermediate gear 33. Thus, when electrical driving pulses
are emitted from the pulse generator 15 the pulse motor 34 is actuated
through the lead wires 31 thereby rotating the motor shaft through
a prescribed angle. Then the rotation of the motor shaft is transmitted
to the indicating wheels 32 through the intermediate gear 33 digitally
indicating the consumption of a fluid.
Referring specially to FIG. 3 there will now be described an intermittent-movement
conversion means 40 for driving the pulse generator 15. The aforesaid
magnetic disc 21 is fixed on a shaft 41 supported at the lower plate
porton 14b, while, at the same time, on such shaft 41 is also fixed
a gear 42. The gear 42 constitutes a reduction gear mechanism together
with a series of gears including those 43 44 supported on the shaft
16 those 45 46 supported on the shaft 17 and those 47 48 supported
on the shaft 19. Also on the shaft 19 is fixed a ratchet wheel 51
mated in an engaged manner with a pawl 52 for preventing reversing
so as to allow the shaft 19 to rotate only in one direction.
As shown on an enlarged scale in FIGS. 4 to 6 a driving disc 53
is fixed on the shaft 19. An arcuate recess 53a is formed at the
periphery of the disc 53 over an angular range of about 120.degree..
On the shaft 19 is supported a cam plate 54 capable of rotating
thereon in a manner kept overlapped on the driving disc 53. The
cam plate 54 has a dwell portion 54a of the same radius and diametrically
opposite cam grooves 54b formed on the outer periphery thereof.
A pin 54c is formed integrally with one side of the cam plate 54
protruding laterally therefrom and penetrating into the arcuate
recess 53a of said driving disc 53. Accordingly, the cam plate 54
and the driving disc 53 are allowed to move rotatively in a relative
manner only through a limited angle of about 90.degree. according
to the relationship between the arcuate groove 54b and the pin 54c.
Meanwhile, on a shaft 20 is rotatably supported a spring drum 55
whose gear 55a, formed on the outer periphery thereof, is engaged
with the gear 50 of the reduction gear mechanism. Within the drum
55 a spiral spring 56 is so wound round the shaft 20 as to be in
contact with the inner wall of the drum 55. The outer end 56a of
the spiral spring 56 is attached to the drum 55 while the inner
end 56b is attached to a boss 57b of an intermittently-driven member
57. The intermittently-driven member 57 has four projections 57a
integrally formed on the outer periphery thereof so spaced as to
provide an angle of 90.degree. between each two adjacent projections,
presenting the configuration of a gear as a whole. These projections
57a, as will be described hereinafter, are so shaped as to be engaged
with the cam grooves 54b on the cam plate 54. The member 57 rotatably
mounted on the shaft 20 is forced by the biasing force of the spring
56 to rotate only in one direction. Further, as shown in FIG. 4
the intermittently driven member 57 is usually so kept as to bring
any two adjacent ones of the four projections 57a into contact with
the dwell portion 54a of the cam plate 54 so that it may not be
able to rotate.
The intermittently-driven member 57 has a gear 58 which is provided
integral therewith and engaged the gear 58 and serves as an output
member.
There will now be described the operation of a flow meter with
the aforementioned construction in accordance with the present invention.
The flow rate of tap water is picked up by the detecting device
10 as a continuous rotation of the output member 12. The rotation
is directly transmitted to the input member 21 by the magnetic coupling
between the magnetic discs 22 and 21. The rotation of the input
member 21 is reduced by the reduction gear mechanism and transmitted
to the driving disc 53 and the spring drum 55. Then the driving
disc 53 rotates clockwise as indicated by the arrow P in FIG. 4
in accordance with the rotation of the shaft 19. After one end of
the arcuate recess 53a gets engaged with the pin 54c of the cam
plate 54 the cam plate 54 is also rotated clockwise together with
the disc 53. On the other hand, by the rotation of the spring drum
55 there is accumulated in the spiral spring 56 the biasing energy
to rotate the driven member 57 counterclockwise as shown in FIG.
4. However, the member 57 may not be able to rotate while it is
engaged with the dwell portion 54a of the cam plate 54. When one
of the cam grooves 54b on the cam plate 54 reaches one of the projections
57a on the member 57 the projection 57a rapidly falls into the
corresponding cam groove 54b as shown in FIG. 5 by means of the
biasing force fully accumulated counterclockwise about the member
57 by the spring 56. The member 57 further rotates counterclockwise
by the biasing force of the spring, and the cam plate 54 is rotated
clockwise relatively to the driving disc 53 by the rotating force
of the member 57. Consequently, the intermittently-driven member
57 comes again into contact with the dwell portion 54a of the cam
plate 54 thereby stopping at the position where it has rotation
counterclockwise through an angle of 90.degree.. The rapid rotation
of the driven member 57 during that time interval rotates the rotor
25 instantaneously through a prescribed angle (e.g., 90.degree.)
through the output gear 58 the gear 24 and the rotary shaft 23
so that electrical pulse voltage is generated by the pulse generator
15. The electrical pulse voltage is transmitted to the pulse motor
34 through the lead wires 31 thereby providing the rotary drive
responding to one pulse at the indicating wheels 32.
In this embodiment, the flow meter is so constructed that each
passage of 1 m.sup.3 of tap water rotates the intermittently-driven
member 57 through an angle of 90.degree. intermittently, generates
one pulse from the pulse generator 15 and indicates 1 m.sup.3 of
consumption of the fluid at the indicating wheels 32.
The flow meter according to the present invention uses the cam
plate 54 and the intermittently-driven member 57 with special configuration,
so that the interval between the shafts 19 and 20 may be minimized,
and besides, the shafts 16 17 and 18 for supporting other reduction
gears may be allowed to be arranged around the said shafts 19 and
20 only requiring very narrow spacing. Since the rotor 25 of the
pulse generator 15 of this invention is always intermittently rotatively
driven only in one direction, the pulse motor 34 can constantly
transmit the intermittent rotation in a fixed one direction to the
indicating wheels 32 by means of the pulse voltage generated. Therefore,
no complicated means for controlling forward or reverse rotation
is required between the indicating wheels 32 and the pulse motor
34. Moreover, the driving of the pulse motor 34 requires a relatively
small amount of energy, so that the pulse generator 15 may be miniaturized.
Thus the pulse generator 15 and the intermittent-movement conversion
means 40 may be contained wholly in a single small cylindrical casing
13 providing an advantage of being able to removably mount the
casing 13 as a single unit on the detecting device 10.
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