U.S. patent application number 11/197381 was filed with the patent office on 2007-02-08 for peristaltic pump.
This patent application is currently assigned to Molon Motor and Coil Corporation. Invention is credited to Ralph Bley, Ronald A. Glaser, Emilio A. JR. Ramirez, Athanase N. Tsergas.
Application Number | 20070031272 11/197381 |
Document ID | / |
Family ID | 37717756 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070031272 |
Kind Code |
A1 |
Ramirez; Emilio A. JR. ; et
al. |
February 8, 2007 |
Peristaltic pump
Abstract
A peristaltic pump for dispensing liquid includes a front casing
portion, a rear casing snap-fitted together with the front casing
portion, a rotor confined between the front casing portion and the
rear casing portion, a plurality of rollers mounted in the rotor,
and a flexible tube compressed at equally spaced intervals by the
plurality of rollers. The pump is resistant to constant torques and
vibrations caused by a machine to which it is attached so that the
pump does not become loose and fall apart. In a first embodiment
for low torque and low vibration operations, the pump is screwless.
In a second embodiment for high torque and high vibration
operations, two screws secure a synchronous gear motor to the
pump.
Inventors: |
Ramirez; Emilio A. JR.;
(Roselle, IL) ; Glaser; Ronald A.; (Arlington
Heights, IL) ; Bley; Ralph; (McHenry, IL) ;
Tsergas; Athanase N.; (Wood Dale, IL) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Molon Motor and Coil
Corporation
Rolling Meadows
IL
|
Family ID: |
37717756 |
Appl. No.: |
11/197381 |
Filed: |
August 5, 2005 |
Current U.S.
Class: |
417/477.1 |
Current CPC
Class: |
F04B 43/1253
20130101 |
Class at
Publication: |
417/477.1 |
International
Class: |
F04B 43/12 20060101
F04B043/12 |
Claims
1. A peristaltic pump for dispensing liquid, comprising: a. a front
casing portion; b. a rear casing portion snap-fitted together with
the front casing portion; c. a rotor confined between the front
casing portion and the rear casing portion; d. a plurality of
rollers mounted in the rotor; and e. a flexible tube compressed at
equally spaced intervals by the plurality of rollers; wherein the
pump is resistant to constant torques and vibrations.
2. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: at least a pair of open-ended boxes and spring
clip pairs configured to snap-fit together the front casing portion
and the rear casing portion.
3. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: a tongue in a recess and a mating groove
configured to snap-fit together the front casing portion and the
rear casing portion.
4. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: a bracket formed integrally with the front
casing portion.
5. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: at least a pair of bosses and sleeves aligned
and fused together by ultrasonic welding on the front casing
portion and the rear casing portion, respectively.
6. A peristaltic pump for dispensing liquid according to claim 5,
further comprising: a skirt at least partially surrounding each of
the sleeves on the rear casing portion.
7. A peristaltic pump for dispensing liquid according to claim 5,
further comprising: a synchronous gear motor having ears and being
attached therethrough by ultrasonic welding to the rear casing
portion.
8. A peristaltic pump for dispensing liquid according to claim 7,
further comprising: screws passing through the ears on the
synchronous gear motor and the sleeves on the rear casing portion
and being secured at the front casing portion so that the pump is
resistant to high torques and high vibrations.
9. A peristaltic pump for dispensing liquid according to claim 7,
further comprising: an output shaft extending from the motor and
rotating the rotor.
10. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: an inlet channel formed integrally on the front
casing portion and configured to hold the flexible tube in
place.
11. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: an outlet channel formed integrally on the
front casing portion and configured to hold the flexible tube in
place.
12. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: an inlet suction branch configured to bring the
liquid flowing into the flexible tube.
13. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: a plurality of mated inserts and barrels formed
integrally on the rotor and configured to carry the plurality of
rollers.
14. A peristaltic pump for dispensing liquid according to claim 13,
further comprising: a dowel mounted inside the rotor and configured
to align the plurality of mated inserts and barrels.
15. A peristaltic pump for dispensing liquid according to claim 1,
further comprising: T-shaped supports configured to reinforce the
rotor.
16. A screwless peristaltic pump for dispensing liquid, comprising:
a. a front casing portion; b. a rear casing portion snap-fitted
together with the front casing portion; c. at least a pair of
bosses and sleeves configured to be heat-welded together between
the front casing portion and the rear casing portion; d. a rotor
confined between the front casing portion and the rear casing
portion; e. a plurality of rollers mounted in the rotor; and f. a
flexible tube compressed at equally spaced intervals by the
plurality of rollers; wherein the pump is resistant to low torques
and low vibrations.
17. A screwless peristaltic pump for dispensing liquid according to
claim 16, further comprising: at least a pair of open-ended boxes
and spring clip pairs configured to snap-fit together the front
casing portion and the rear casing portion.
18. A screwless peristaltic pump for dispensing liquid according to
claim 16, further comprising: a recess and a mating groove
configured to snap-fit together the front casing portion and the
rear casing portion.
19. A screwless peristaltic pump for dispensing liquid according to
claim 16, further comprising: a synchronous gear motor having ears
and being attached therethrough by ultrasonic welding to the rear
casing portion.
20. A screwless peristaltic pump for dispensing liquid according to
claim 16, further comprising: a skirt at least partially
surrounding each of the sleeves.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to peristaltic pumps, in particular to
a small pump for dispensing liquid detergent into a dish washing
machine.
[0003] 2. Discussion of the Prior Art
[0004] Peristaltic pumps are well known in the prior art and may be
defined as pumps which produce pulse-like contractions that propel
matter along inside a tube.
[0005] In FIG. 1, there is shown a prior art device that was
manufactured by Knight Equipment International, Inc., of Costa
Mesa, California, now Knight, Inc. of Northbrook, Ill.
[0006] Inside a casing 10, there is a pump 12 in which a triangular
rotor 14 rotates to compress a flexible rubber tube 16 against a
curved wall 30 at points A and B. These points A and B change along
the length of the tube 16 as the rotor 14 rotates around its
central axis 18. Three pins 20 hold three rollers 22 at tips X, Y
and Z of the rotor 14 while four screws 24 hold front and back
portions of the casing 10 together. The tube 16 has an inlet
suction branch 16C and an outlet delivery branch 16D. Arrows I and
O indicate the direction of flow of liquid detergent into and out
of the tube 16. A clear, hard plastic cover 26 with a tab 28 allows
a user to view and to have access to the interior of the casing 10
in order to replace or repair any parts of the pump 12 and the
rotor 14 which may break.
[0007] One disadvantage of this prior art device is that the
constant vibration of an industrial washing machine in which it is
used tends over time to cause the screws 24 to work loose from the
casing 10, thus causing the pump 12 inside to fail. Also, the
constant vibration causes the pins 20 holding the rollers 22 in the
rotor 14 to work loose and push up against the cover 26 until the
cover 26 pops off. Once again the pump 12 fails. Thus, it is a
problem in the prior art to develop a peristaltic pump which is
resistant to constant vibrations that eventually caused earlier
devices to become loose and fail.
SUMMARY OF THE INVENTION
[0008] The invention may be summarized as a small screwless
peristaltic pump which is resistant to constant vibrations caused
by a machine to which it is attached so that the pump does not
become loose and fall apart.
[0009] A primary object of the invention is to hold the pump
together without screws when the pump is used in low torque and low
vibration operations.
[0010] A secondary object of the invention is to support a motor
onto a rear casing portion of the housing.
[0011] A tertiary object of the invention is to make the pump, its
internal rollers and a flexible tube impervious to deleterious
ingredients contained in liquid detergent.
[0012] A key advantage of the present invention is that only a
predetermined amount of the liquid detergent enters the pump
because the synchronous motor, as controlled electronically, meters
the detergent to prevent waste in the dish washing machine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention and its other advantages may be best
understood by reference to the accompanying drawings and the
subsequent detailed description of the preferred embodiments.
[0014] FIG. 1 is a front elevational view of a known prior art
device.
[0015] FIG. 2 is an exploded front perspective view of a first
embodiment of the invention.
[0016] FIG. 3 is an exploded front perspective view of a rotor and
rollers inside the first embodiment.
[0017] FIG. 4 is a top end view of a front portion of a casing of
the first embodiment.
[0018] FIG. 5 is a front inside elevational view of a back portion
of the casing of the first embodiment.
[0019] FIG. 6 is an assembled perspective view of the first
embodiment.
[0020] FIG. 7 is an exploded rear perspective view of a second
embodiment of the invention.
[0021] FIG. 8 is an exploded front perspective view of a rotor and
rollers inside the second embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] There are two basic preferred embodiments: a first
embodiment for low torque and low vibration operations; and a
second embodiment for high torque and high vibration
operations.
[0023] In FIG. 2, the first embodiment is illustrated. There is a
small plastic peristaltic pump 112 contained in a main housing
which has a front casing portion 100 and a cover or a rear casing
portion 110. The front casing portion 100 and the rear casing
portion 110 are snap-fitted together in a manner described below. A
bracket 164 is formed integrally with a side of the front casing
portion 100. This bracket 164 attaches the main housing containing
the pump 112 to a dish washing machine (not shown). An electrical
plug 174 allows alternating current to be carried through wires 176
from an activator (not shown) when it is switched on by a user who
desires to wash a load of dishes. Upon activation, an inlet suction
branch 106 brings a predetermined amount of liquid detergent
flowing from a reservoir (not shown) in a direction I into a
flexible rubber U-shaped tube 116 held in place at an inlet to the
pump 112 by a U-shaped inlet channel 104 integrally formed on a top
surface of the front casing portion 100. Inside the pump 112, there
is a plurality of plastic rollers 122 on tips X, Y and Z of a
triangular plastic rotor 114 confined between the front casing
portion 100 and the rear casing portion 110. The rollers 122
compress the flexible tube 116 at equally spaced intervals against
an interior side of a curved wall 130. Although three rollers 122
are shown, a manufacturer may choose to use more or less rollers,
for example, four or two rollers instead. Nevertheless, three
rollers 122 are preferred. The rollers 122 are rolled along the
flexible tube 116 as they are rotated by the rotor 114 which is
turned by an output shaft 118 extending from a synchronous gear
motor 132. Ears 166 project from opposite sides of the motor 132.
Bosses 142 on an outer periphery of the front casing portion 100
extend through hollow cylindrical sleeves 144 into upper and lower
holes in the ears 166 and are ultrasonically heated until they melt
to spot weld the motor 132 to the rear casing portion 110.
[0024] As seen in FIG. 2, only a predetermined amount of the liquid
detergent enters the pump 112 because the synchronous motor 132
meters the detergent to prevent waste in the dish washing machine.
The amount of liquid is predetermined by the signal sent to the
motor 132 which then turns its shaft 118 and the rotor 114 mounted
thereon a predetermined number of times.
[0025] The motor 132 is rated at 120 volts of alternating current
(AC) at 60 hertz (Hz). The rated current is 0.05 amps and the rated
speed is 20 revolutions per minute (rpm), plus or minus 10%.
[0026] Pulse-like contractions are produced inside the flexible
tube 116. These contractions propel the liquid detergent in spurts
along the inside of the flexible tube 116 held in place at an
outlet from the pump 112 by a U-shaped outlet channel 108 until the
liquid detergent is dispensed by being squirted out of an outlet
delivery branch 160 in a direction O into the dish washing machine
(not shown). The U-shaped outlet channel 108 is formed integrally
on a top surface of the front casing portion 100.
[0027] Instead of the metal pins used in the prior art device shown
in FIG. 1, the pump 112 in FIG. 2 is secured together against the
constant vibrations of the dish washing machine by three types of
plastic devices for snap-fitting the front casing portion 100
together with the cover or rear casing portion 110. The first type
is a C-shaped groove (not shown) in a circular recess 135 into
which a C-shaped tongue 136 is inserted. In an alternate
embodiment, at least a pair of straight grooves and a mating pair
of straight tongues 136 may be used. The second type of plastic
device is a trio of square, open-ended boxes 138 into which a trio
of springy, plastic clip pairs 140 are inserted. At least two of
these boxes 138 and clip pairs 140 are needed for the front casing
portion 100 and the rear casing portion 110 to be snap-fitted
together. The third type of plastic device is the pair of bosses
142 on each side of the front casing portion 100. The bosses 142
are inserted through the pair of hollow cylindrical sleeves 144. In
an alternate embodiment, only one boss 142 and one sleeve 144 may
be used. Note that the groove in the recess 135, the boxes 138 and
the bosses 142 are positioned on an outer periphery of the front
casing portion 100 while the tongue 136, the clip pairs 140 and the
sleeves 144 are positioned on an outer periphery of an interior
wall of the rear casing portion 110. However, in an alternate
embodiment, the groove in the recess 135, the boxes 138 and the
bosses 142 may be positioned on the rear casing portion 110 while
the tongue 136, the clip pairs 140 and the sleeves 144 may be
positioned on the front casing portion 100. An ultrasonic welding
rod (not shown) is applied to three areas on an exterior wall of
the rear casing portion 110 where the bosses 142 are inserted
through the sleeves 144 into the ears 166 in order to heat and melt
each boss 142 into its aligned sleeve 144 and ear 166 so that the
boss 142, the sleeve 144 and the ear 166 are fused together. Thus,
the pump 112 is not jarred apart by the constant vibrations caused
by the dish washing machine.
[0028] In FIG. 3, the triangular rotor 114 for low torque and low
vibration operations is illustrated. The rotor 114 and its rollers
122 are exploded apart to show how they are connected together. A
front face 146 of the rotor 114 has formed integrally on its inner
side three stepped male inserts 148. A rear face 150 has formed
integrally on its inner side three aligned cylindrical barrels 152
with which the male inserts 148 mate. Each roller 122 has a
cylindrical bore 156 through its center along its longitudinal axis
158. Note that a dowel 154 is mounted inside the rotor 114 and
aligns the plurality of mated inserts 148 and barrels 152 around a
central D-shaped bore 172. A single central large cylindrical
barrel 170 carries the dowel 154 and surrounds the D-shaped bore
172 through which the shaft 118 of FIG. 2 with its D-shaped cross
section passes in order to rotate the rotor 114.
[0029] In FIG. 3, the rotor 114 is assembled in the following
manner. First, the rollers 122 are slipped onto the barrels 152.
Second, the inserts 148 are plugged into the bores 156 of the
barrels 152 so that the mated inserts 148 and the barrels 152 carry
the rollers 122. Simultaneously, the dowel 154 is inserted into a
bore (not shown) made in the inner side of the front face 146. An
ultrasonic welding rod (not shown) is applied to three areas on an
outer side of the rear face 150 where the inserts 148 are plugged
into the barrels 152 so that the inserts 148 and the barrels 152
are fused together. However, care must be taken so that too much
heat is not applied in order to prevent the rollers 122 on the
barrels 152 from being deformed.
[0030] In FIG. 4, there is shown a top end view of the front casing
portion 100 which functions as part of the main housing for both
the first and second embodiments. The U-shaped inlet channel 104
secures an entrance for the flexible tube (not shown) while the
U-shaped outlet channel 108 secures an exit for the flexible tube.
A top of one box 138 is also seen. In the first embodiment for low
torque and low vibration operations, a pair of bosses 142 on each
side, of which only the top boss 142 is seen, is insertable through
the pair of hollow cylindrical sleeves 144 on each side shown in
FIG. 5 on the interior wall of the rear casing portion 110. In FIG.
4, the bracket 164 attaches the front casing portion 100 to the
dish washing machine (not shown). The front casing portion 100 is
also secured to the rear casing portion 110 of FIG. 5 by the trio
of clip pairs 140 which are inserted into the boxes 138 of FIG. 4,
of which only one box 138 is shown in FIG. 4. Likewise, in FIG. 5,
the circular tongue 136 arranged on the interior wall of the rear
casing portion 110 is inserted into the groove (not shown in FIG.
4, but see the back of the groove in the recess 135 illustrated in
FIG. 2). In FIG. 5, an opening 162 through the center of the rear
casing portion 110 allows the output shaft 118 seen in FIG. 2 to
extend therethrough to engage with and drive the rotor 114 of FIG.
3.
[0031] In FIG. 6, the pump 112 is shown to be assembled with the
motor 132. The operation of the pump 112 and the motor 132 in this
first embodiment may be understood by following the path of
movement of the liquid therethrough. Note that the liquid may be
other than a detergent. Initially, the motor 132 is turned on when
it receives a signal through the wires 176 of the plug 174 to meter
the flow of liquid in the direction I into the inlet suction branch
106 which leads to the flexible tube 116 that is held securely by
the U-shaped inlet channel 104. To prevent waste of liquid
detergent in the dish washing machine, the signal energizes the
motor 132 to turn its shaft 118 seen in FIG. 2 a predetermined
number of times depending upon whether a small, medium or large
amount of detergent is needed to clean the load in the dish washing
machine. A predetermined amount of the liquid then enters the pump
112 where the rollers 122 of FIGS. 2 and 3 intermittently compress
the flexible tube 116 so that the even flow of liquid is converted
into pulses of liquid. These liquid pulses exit the pump 112
through the flexible tube 116 that is held securely by the U-shaped
outlet channel 108. The liquid is then squirted out of the outlet
delivery branch 160 in the direction O into the dish washing
machine (not shown). While the rotor 114 of FIGS. 2 and 3 is driven
by the motor 132, the pump 112 is seen in FIG. 6 to be held
together by the front casing portion 100 and the rear casing
portion 110 which are secured by the two clip pairs 140 in the two
boxes 138. Another clip pair 140 in its box 138 is hidden from
view. The pairs of sleeves 144 on the rear casing portion 110 and
the pairs of bosses 142 on the front casing portion 100 stuck
therein are also hidden from view. In this first embodiment for low
torque and low vibration operations, the groove in the recess 135
and its mating tongue 136 of FIG. 2 are not illustrated in FIG. 6
because they are hidden inside the front casing portion 100 and the
rear casing portion 110, respectively. The bracket 164 is shown for
attaching the entire assembly to the dish washing machine (not
shown).
[0032] Note in FIG. 2 that there are no screws holding the pump 112
together with its housing which includes the front casing portion
100 and the rear casing portion 110. Also, in this first embodiment
for low torque and low vibration operations, there are no screws
supporting the motor 132 onto the exterior wall of the rear casing
portion 110. Note further that the pump 112, the rollers 122 and
the tube 116 are all impervious to deleterious ingredients
contained in the liquid detergent.
[0033] In FIG. 7, the second embodiment for high torque and high
vibration operations is illustrated. The pump 112 is contained in
the main housing which has the front casing portion 100 and the
cover or rear casing portion 110. The front casing portion 100 and
the rear casing portion 110 are snap-fitted together in the manner
described below. The bracket 164 is formed integrally with a side
of the front casing portion 100 and attaches the main housing
containing the pump 112 to the dish washing machine (not shown).
The electrical plug 174 allows alternating current to be carried
through the wires 176 from the activator (not shown) when it is
switched on by a user. Upon activation, the inlet suction branch
106 brings a predetermined amount of liquid detergent flowing from
a reservoir (not shown) in the direction I into the flexible tube
116 held in place at the inlet to the pump 112 by the U-shaped
channel 104 integrally formed on the top surface of the front
casing portion 100. Inside the pump 112, there is a plurality of
rollers 122 on tips X, Y and Z of the rotor 114 confined between
the front casing portion 100 and the rear casing portion 110. The
rollers 122 compress the flexible tube 116 at equally spaced
intervals against the interior side of the curved wall 130. The
rollers 122 are rolled along the flexible tube 116 as they are
rotated by the rotor 114 which is turned by the output shaft 118
(not shown but see FIG. 2) extending from the motor 132. Ears 166
of which only one is seen in FIG. 7, project from opposite sides of
the motor 132. Screws 168 are inserted into upper holes in the ears
166, extend through the upper sleeves 144 on the rear casing
portion 110 and pass through bores 178 in the front casing portion
100 where the screws 168 are secured at their ends by bolts 182 of
which only one is shown. The bosses 142 extend from the front
casing portion 100 through the lower sleeves 144 into the lower
holes in the ears 166 and are ultrasonically heated until they melt
to spot weld the motor 132 to the rear casing portion 110. Of
course, in an alternate embodiment, the screws 168 may be inserted
into the lower holes in the ears 166 and the bosses 142 may be
extended through the upper holes in the ears 166 to achieve the
same result. Note that this combination of screws 168 and bosses
142 is intended for high torque and high vibration operations.
[0034] Pulse-like contractions are produced inside the flexible
tube 116 as the rotor 114 rotates the rollers 122 along the curved
wall 130 to compress the tube 116. These contractions propel the
liquid detergent in spurts along the inside of the tube 116 which
is held in place at the outlet from the pump 112 by the U-shaped
channel 108 until the liquid detergent is dispensed by being
squirted out of the delivery branch 160 in the direction O into the
dish washing machine (not shown). The channel 108 is formed
integrally on a top surface of the front casing portion 100.
[0035] Instead of the metal pins used in the prior art device shown
in FIG. 1, the pump 112 in FIG. 7 is secured together against the
constant vibrations of the dish washing machine by three types of
plastic devices for snap-fitting the front casing portion 100
together with the cover or rear casing portion 110. The first type
is the C-shaped groove 134 into which the C-shaped tongue 136 is
inserted. The tongue 136 is not shown in FIG. 7, but see FIG. 2. In
an alternate embodiment, at least a pair of straight grooves 134
and a mating pair of straight tongues 136 may be used. The second
type of plastic device is the trio of square boxes 138 into which a
trio of springy clip pairs 140 are inserted. Only one pair of the
clips 140 is seen in FIG. 7. At least two of these boxes 138 and
clip pairs 140 are needed for the front casing portion 100 and the
rear casing portion 110 to be snap-fitted together. The third type
of plastic device is the pair of bosses 142, one on each side of
the front casing portion 100. The bosses 142 are inserted through
the lower sleeves 144 into the lower ears 166 on the motor 132.
Note that the groove 134, the boxes 138 and the bosses 142 are
positioned on an outer periphery of the front casing portion 100
while the tongue 136 (not shown in FIG. 7 but see FIG. 2), the clip
pairs 140 and the sleeves 144 are positioned on an outer periphery
of an interior wall of the rear casing portion 110. However, in an
alternate embodiment, the groove 134, the boxes 138 and the bosses
142 may be positioned on the rear casing portion while the tongue
136 of FIG. 2, the clip pairs 140 and the sleeves 144 may be
positioned on the front casing portion 100. An ultrasonic welding
rod (not shown) is applied to three areas on the exterior wall of
the rear casing portion 110 where the bosses 142 are inserted
through the lower sleeves 144 into the lower holes in the ears 166
in order to heat and melt each boss 142 into its aligned lower
sleeve 144 and lower hole of the ear 166 so that the boss 142, the
sleeve 144 and the ear 166 are fused together. Thus, the pump 112
is not jarred apart by the constant vibrations caused by the dish
washing machine.
[0036] In this second embodiment shown in FIG. 7, there is a skirt
180 at least partially surrounding the sleeves 144 on each side of
the rear casing portion 110 to form a recessed area into which the
ears 166 may fit so as to prevent wobbling of the motor 132 when it
is activated. There are also skirts 180 in the first embodiment for
low torque and low vibration operations. However, the skirts 180
are not seen in the first embodiment because FIG. 2 is a front
perspective view which hides the skirts 180.
[0037] In FIG. 8, the triangular rotor 114 for high torque and high
vibration operations is illustrated. Three T-shaped supports 184
reinforce the rotor 114 against high torque and high vibrations. In
the first embodiment shown in FIG. 3 for low torque and low
vibration operations, there are no T-shaped supports 184
reinforcing the rotor 114.
[0038] In FIG. 8, the rotor 114 and its rollers 122 are exploded
apart to show how they are connected together. The front face 146
of the rotor 114 has formed integrally on its inner side three
stepped male inserts 148. The rear face 150 has formed integrally
on its inner side three aligned cylindrical barrels 152 with which
the male inserts 148 mate. Each roller 122 has a cylindrical bore
156 through its center along its longitudinal axis 158. The dowel
154 is mounted inside the rotor 114 and aligns the plurality of
mated inserts 148 and barrels 152 around the central D-shaped bore
172. The single central large cylindrical barrel 170 carries the
dowel 154 and surrounds the D-shaped bore 172 through which the
shaft 118 of FIG. 2 with its D-shaped cross section passes in order
to rotate the rotor 114.
[0039] In FIG. 8, the rotor 114 is assembled in the following
manner. First, the rollers 122 are slipped onto the barrels 152.
Second, the inserts 148 are plugged into the bores 156 of the
barrels 152 so that the mated inserts 148 and the barrels 152 carry
the rollers 122. Simultaneously, the dowel 154 is inserted into a
bore (not shown) made in the inner side of the front face 146. The
ultrasonic welding rod (not shown) is applied to three areas on the
outer side of the rear face 150 where the inserts 148 are plugged
into the barrels 152 so that the inserts 148 and the barrels 152
are fused together. However, care must be taken so that too much
heat is not applied in order to prevent the rollers 122 on the
barrels 152 from being deformed.
[0040] Although the present invention has been described by way of
two preferred embodiments, other modifications will be realized by
those persons skilled in this particular technology after reading
this disclosure. However, these modifications may be considered
within the scope of the appended claims if such modifications do
not depart from the spirit of this invention.
* * * * *