Rotary expansible chamber devices – Interengaging rotating members – Like rotary members
Reexamination Certificate
2000-03-31
2001-12-11
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Interengaging rotating members
Like rotary members
C418S107000
Reexamination Certificate
active
06328547
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary pump suitable for transporting liquid foods.
2. Description of the Related Art
In a rotary pump of the type set forth above, the recent prior art has been disclosed in commonly owned U.S. Pat. No. 5,370,514, issued to Morita et al.
Since the present invention has some common structures with the above-identified commonly owned prior art, the construction of the prior art will be discussed hereinafter in detail in order to facilitate clear understanding of the present invention.
FIGS. 10 and 11
show the commonly owned prior art. In these drawings, the reference numerals
1
A and
1
B denotes rotors. From each of rotors
1
A and
1
B. a short rotor shaft
2
is provided from the central portion of one end surface thereof. A threaded bore
3
is coaxially formed from the end surface of the rotor shaft
2
. A pumping segment
4
is integrally formed on the outer peripheral portion of each rotor
1
A and
1
B.
The reference numeral
6
denotes a pump casing. The pump casing
6
includes a main casing defining a concave pumping chamber
7
loosely accommodating the pumping segments
4
or revolution therein and formed with a suction port
8
and a discharge port
9
, and a casing cover
11
detachably attached on the main casing
10
flush with the end surface of each rotor
1
A and
1
B by means of bolts and nuts.
The reference numeral
12
A and
12
B denote hollow rotor drive shafts provided corresponding to the rotors
1
A and
1
B. The rotor drive shaft is supported by means of a bearing
14
within a gearbox
13
for the drive shaft for rotation and restricting movement in an axial direction. The reference numeral
15
denotes a rotor fastening bolt inserted through a hollow portion of each of the hollow rotor drive shafts
12
A and
12
B from one end to the other end. A bolt head
15
a
of the rotor fastening bolt
15
is engaged with one end surface rotor drive shaft
15
.
A hollow portion
16
a
at the tip end of each rotor drive shaft
12
A and
12
B is externally engaged with the rotor shaft
2
of each rotor
1
A and
1
B. In conjunction therewith, a threaded portion
15
b
at the tip end of the rotor fastening bolt
15
is threadingly engaged with the threaded bore
3
of the rotor shaft
2
.
In
FIG. 11
, the reference numeral
17
denotes a gearbox for a transmission shaft. A transmission shaft
21
is rotatably supported via bearings
18
and
19
within the gearbox
17
, and is connected to a motor (not show). A gear
22
is mounted on the transmission shaft
21
. In the gearbox
13
for drive shaft, gears
23
a
and
23
b
for transmitting rotation for driving a pair of rotor drive shafts
12
A and
12
B in mutually opposite direction in synchronism with each other and a gear
23
c
meshing with the gear
22
mounted on the transmission shaft
21
are provided. Accordingly, a driving force of the motor to be transmitted to the transmission shaft
21
is transmitted to one rotor shaft
12
A via the gears
22
and
23
c
. The driving force of the rotor drive shaft
12
A is transmitted to the other rotor drive shaft
12
B via the gears
23
a
and
23
b.
For assembling the rotary pump constructed as set forth above, the pumping segment
4
of each rotor
1
A and
1
B is received within the pumping chamber
7
of the main casing
10
. In conjunction therewith, each rotor shaft
2
is engaged with the hollow portion
16
a
at the tip end of the hollow rotor drive shaft
12
supported within the gearbox
13
. Then, the rotor fastening bolt
15
is inserted within the rotor drive shaft
12
from one end to threadingly engage the threaded portion
15
b
at the tip end thereof with the threaded bore
3
of the rotor shaft
2
. Then, the bolt head
15
a
is rotated by a rotary tool, such as spanner or the like for tightening to draw each rotor
1
A and
1
B toward the rotor drive shaft
12
for fixedly fastening.
In the rotary pump assembled as set forth above, a rotational torque of the not shown motor is transmitted to the transmission shaft
21
. Both of the rotor drive shafts
12
driven to rotate via the transmission shaft
21
drive to rotate both rotors
1
A and
1
B in mutually opposite directions in synchronism with respect to each other as shown by arrows in FIG.
11
. Thus, by action of the pumping segments
4
rotated within the pumping chambers
7
, liquid is sucked into the pumping chamber
7
through the suction port
8
and is pressurized and fed to the discharge port
9
. In this case, overall inner side surface of the casing cover
11
is a flat surface forming in flush with the external end surface of the rotors
1
A and
1
B so as not to form recessed portion between the rotors
1
A and
1
B. Therefore, retention of the transported liquid flowing through the pumping chamber
7
will never be caused. Accordingly, washing of the pumping chamber can be easily performed.
On the other hand, upon disassembling the rotors
1
A and
1
B, the nuts
20
are loosen to remove the casing cover
11
, and thereafter, the rotors
1
A and
1
B are disassembled easily by simply loosening the rotor fastening bolts
15
.
As can be clear from the construction, in the prior art, the gearbox
16
for the transmission shaft
21
is provided separately from the gearbox
13
of the drive shaft, and driving force has to be transmitted to the rotor drive shaft
12
via the gear mounted on the transmission shaft
21
on the side of the motor and the gear
23
a
housed within the gearbox
13
for the drive shaft.
Conventionally, in addition to a pair of rotor drive shafts
12
A and
12
B for driving the rotor as set forth above, the transmission shaft
21
for transmitting the rotational torque of the motor to the rotor drive shafts
12
A and
12
B, and thus at least three shaft in total are required. Therefore, the construction is inherently complicate.
On the other hand, as can be clear from the construction set forth above, in the recent prior art, the rotor fastening bolt
15
inserted into the hollow portion of the hollow rotor drive shaft
12
is rotated by rotating the bolt head
15
at the rear end portion with the rotary tool in the condition where the threaded portion
15
b
at the tip end is threadingly engaged with the rotor
1
A (
1
B) to draw the rotor
1
A backward by the rotor fastening bolt
15
and to abut the bolt head
15
a
onto the end surface of the hollow rotor drive shaft
12
. On the other hand, upon disassembling, the rotors
1
A and
1
B can be disassembled easily only by loosening the rotor fastening bolt
15
by rotatingly operating the bolt head
15
a
. Also, the mating surfaces of the rotor
1
A (
1
B) and opposing casing cover
11
may be formed in flush. Coupling between the rotor
1
A (
1
B) and the hollow rotor drive shaft
12
A (
12
B) is effected by externally engaging the tip end portion of the drive shaft and by maintaining external engagement by drawing force applied by tightening the rotor fastening bolt
15
into the rotor shaft
12
. Therefore, connection force therebetween is insufficient. Also, centering of the rotor
1
A (
1
B) and the hollow rotor drive shaft
12
A (
12
B) cannot be complete to possibly cause center vibration.
Furthermore, as shown in
FIGS. 10 and 11
, the conventionally rotary pump defines the pumping chamber
7
with the main casing
10
and the casing cover
11
mounted thereon. A pair of rotors
1
A and
1
B are housed within the pumping chamber
7
. The end surface
1
a
of the casing cover
11
of each of rotors
1
A and
1
B are placed in substantially contacting state with a minimum fine gap required for permitting rotation of the rotor
1
A and
1
B. Both rotors
1
A and
1
B are synchronously rotated in mutually opposite directions by mutually engaging the pumping segments
4
of the rotors
1
A and
1
B by the rotor drive shafts
12
as shown by the arrows of FIG.
11
. Thus, the liquid is sucked into the pumping chamber
7
through the suction port
8
, and pressurized and fed to the discharge port
9
. In this ca
Denion Thomas
Nakanin Co. Ltd
Trieu Theresa
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