U.S. patent application number 12/047964 was filed with the patent office on 2009-09-17 for ultrasonic piezoelectric pump.
This patent application is currently assigned to Korea Institute of Machinery & Materials. Invention is credited to Byung-Oh Choi, Young-Bog HAM, Jeong-Dai Jo, Jung-Ho Park, So-Nam Yun.
Application Number | 20090232681 12/047964 |
Document ID | / |
Family ID | 41063241 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090232681 |
Kind Code |
A1 |
HAM; Young-Bog ; et
al. |
September 17, 2009 |
ULTRASONIC PIEZOELECTRIC PUMP
Abstract
Disclosed is an ultrasonic piezoelectric pump in which a
piezoelectric pump is integrated with a fluid pipe without a check
valve so that the structure can be simplified. The pump includes a
fluid pipe having a hollow part formed therein to permit a fluid to
flow from a fluid source, a piezoelectric actuator inserted into
the hollow part and including a piezoelectric device and a
plurality of fluid holes, a controller connected to a lead wire to
apply a driving power to the piezoelectric device, and a tapered
nozzle inserted into the hollow part in front of the piezoelectric
actuator and tapered forward and downwardly.
Inventors: |
HAM; Young-Bog; (Yuseong-gu,
KR) ; Park; Jung-Ho; (Yuseong-gu, KR) ; Jo;
Jeong-Dai; (Yuseong-gu, KR) ; Yun; So-Nam;
(Yuseong-gu, KR) ; Choi; Byung-Oh; (Yuseong-gu,
KR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Korea Institute of Machinery &
Materials
Yuseong-gu
KR
|
Family ID: |
41063241 |
Appl. No.: |
12/047964 |
Filed: |
March 13, 2008 |
Current U.S.
Class: |
417/413.2 ;
417/322 |
Current CPC
Class: |
F04B 17/003 20130101;
F04B 53/08 20130101 |
Class at
Publication: |
417/413.2 ;
417/322 |
International
Class: |
F04B 17/00 20060101
F04B017/00; F04B 35/04 20060101 F04B035/04 |
Claims
1. An ultrasonic piezoelectric pump comprising: a fluid pipe having
a hollow part formed therein to permit a fluid to flow from a fluid
source; a piezoelectric actuator inserted into the hollow part and
including a piezoelectric device and a plurality of fluid holes; a
controller connected to a lead wire to apply a driving power to the
piezoelectric device; and a tapered nozzle inserted into the hollow
part in front of the piezoelectric actuator and tapered forward and
downwardly.
2. The ultrasonic piezoelectric pump according to claim 1, wherein
the piezoelectric actuator comprises: a case having a through-hole
formed at the center thereof; a frame, inserted into the
through-hole, to which the piezoelectric device is installed; and
the fluid holes formed in the vicinity of the frame to penetrate
the front side to the rear side of the case.
3. The ultrasonic piezoelectric pump according to claim 2, wherein
the piezoelectric device comprises a unimorph comprising: a thin
plate; and a piezoelectric ceramic contacting a side of the thin
plate.
4. The ultrasonic piezoelectric pump according to claim 2, wherein
the piezoelectric device comprises a unimorph comprising: a thin
plate; and a piezoelectric ceramic contacting sides of the thin
plate.
5. The ultrasonic piezoelectric pump according to claim 2, wherein
the piezoelectric device comprises a multi-layer piezoelectric disc
having a plurality of thin piezoelectric ceramics and resonating in
the thickness direction.
6. The ultrasonic piezoelectric pump according to claim 1, wherein
the piezoelectric device comprises: a case having a through-hole
formed at the center thereof; a pipe-shaped cylinder inserted into
the through-hole; a rear plate fixed to the rear side of the
cylinder to close the rear side of the cylinder; a front plate
contacting an inner wall of the cylinder and used as a piston; the
piezoelectric device, provided to connect the rear plate to the
front plate, in which a plurality of piezoelectric ceramics are
laminated; and the fluid holes formed in the vicinity of the
cylinder to penetrate the front side to the rear side of the
case.
7. The ultrasonic piezoelectric pump according to claim 6, wherein
the front plate further comprises a circular rubber ring to seal
the case and to prevent the fluid from entering.
8. The ultrasonic piezoelectric pump according to claim 1, wherein
the piezoelectric actuator comprises: a case having a through-hole
formed at the center thereof; a frame inserted into the
through-hole; a piezoelectric ceramic provided in the frame to
generate a deflection in the radial direction; an elastic member
contacting the front side of the piezoelectric ceramic, a part of
the elastic member inserted into the frame and another part of the
elastic member protruding from the front side of the frame, and the
protruded part having a smaller diameter than that of the part
inserted into the frame and vibrating due to ultrasonic waves
applied to the piezoelectric device; a fixed body to fix the
elastic member to the frame, and through which the elastic member
penetrates; and the fluid holes formed in the vicinity of the frame
to penetrate the front side to the rear side of the case.
9. The ultrasonic piezoelectric pump according to any one of claims
1 to 8, further comprising a distance adjusting circular ring
provided in the fluid pipe to adjust a distance between the
piezoelectric actuator and the tapered nozzle.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a piezoelectric pump, and
more particularly, to an ultrasonic piezoelectric pump in which a
piezoelectric pump is integrated with a fluid pipe without a check
valve so that the structure can be simplified.
[0003] 2. Description of the Related Art
[0004] In general, since parts for small sized electronic products
and medical equipment possibly malfunction or are damaged due to
heat generated therein because degree of integration of transistors
is improved, cooling of the electronic parts is becoming a critical
issue in electronic apparatuses using small electronic parts.
[0005] It is proposed a refrigerant circulation system using a
piezoelectric pump, as a solution for cooling the small sized
electronic components, for suctioning liquid refrigerant and for
vibrating the liquid refrigerant by applying a force to the liquid
refrigerant to discharge the refrigerant in a desired phase(?).
[0006] FIG. 13 is a conceptual view illustrating a conventional
piezoelectric pump. Referring to FIG. 13, the conventional
piezoelectric pump includes a piezoelectric actuator 100 having a
suction port 110 and a discharge port 120, and a piezoelectric
device 200 installed in the piezoelectric actuator 100. The suction
port 110 and the discharge port 120 communicate with fluid pipes
300, respectively.
[0007] Ends of the piezoelectric device 200 are connected to a
controller 400 by lead wires 410 such that the controller 400
applies an electric field to the piezoelectric device 200 to pump a
fluid while being deflected.
[0008] In this structure, the fluid supplied through the fluid pipe
300 is fed into the piezoelectric actuator 100 through the suction
port 110, and the fed fluid is pumped when a voltage is applied to
the piezoelectric device 200 by the controller 400 and then is
discharged out through the discharge port 120.
[0009] The conventional piezoelectric pump includes check valves
500 respectively installed to the suction port 110 and the
discharge port 120 to prevent the fluid from flowing backward when
the fluid is pumped by the deflection of the piezoelectric device
200.
[0010] As such, since the conventional piezoelectric pump is
provided independently from the fluid pipe 300 and the check valves
500 for preventing fluid from flowing backward are provided
independently from the pump, the conventional piezoelectric pump is
not suitable for minimizing electronic products and medical
equipment because it is difficult to make the piezoelectric pump in
a small size.
SUMMARY OF THE INVENTION
[0011] Therefore, the present invention has been made in view of
the above problems, and it is an aspect of the present invention to
provide an ultrasonic piezoelectric pump in which: a piezoelectric
actuator is installed at a center of a fluid pipe; a plurality of
fluid-flow holes is formed around the piezoelectric actuator; and a
tapered nozzle is tapered forward and downwardly in front of the
piezoelectric actuator to force a fluid to be easily discharged and
to have difficulty to flow backward so that a fluid can be smoothly
pumped by the piezoelectric actuator without a check valve while
preventing the fluid from flowing backward.
[0012] It is another aspect of the present invention to provide an
ultrasonic piezoelectric pump in which a voltage applied to a
piezoelectric device is adjusted to quickly deform the
piezoelectric device for the fluid discharge and a frequency is
adjusted to have a voltage waveform to force the piezoelectric
device to be restored slowly so that a fluid can be smoothly
discharged.
[0013] It is still another aspect of the present invention to
provide an ultrasonic piezoelectric pump, a piezoelectric device of
which is driven by ultrasonic waves to force a fluid to flow while
causing flow resonance so that efficiency of heat transfer can be
improved.
[0014] In order to achieve the object, there is provided an
ultrasonic piezoelectric pump comprising: a fluid pipe having a
hollow part formed therein to permit a fluid to flow from a fluid
source; a piezoelectric actuator inserted into the hollow part and
including a piezoelectric device and a plurality of fluid holes; a
controller connected to a lead wire to apply a driving power to the
piezoelectric device; and a tapered nozzle inserted into the hollow
part in front of the piezoelectric actuator and tapered forward and
downwardly.
[0015] The piezoelectric actuator comprises: a case having a
through-hole formed at the center thereof; a frame, inserted into
the through-hole, to which the piezoelectric device is installed;
and the fluid holes formed in the vicinity of the frame to
penetrate the front side to the rear side of the case.
[0016] The piezoelectric device comprises a unimorph comprising: a
thin plate; and a piezoelectric ceramic contacting a side of the
thin plate.
[0017] The piezoelectric device comprises: a case having a
through-hole formed at the center thereof; a pipe-shaped cylinder
inserted into the through-hole; a rear plate fixed to the rear side
of the cylinder to close the rear side of the cylinder; a front
plate contacting an inner wall of the cylinder and used as a
piston; the piezoelectric device, provided to connect the rear
plate to the front plate, in which a plurality of piezoelectric
ceramics are laminated; and the fluid holes formed in the vicinity
of the cylinder to penetrate the front side to the rear side of the
case.
[0018] The front plate further comprises a circular rubber ring to
seal the case and to prevent the fluid from entering.
[0019] The piezoelectric actuator comprises: a case having a
through-hole formed at the center thereof; a frame inserted into
the through-hole; a piezoelectric ceramic provided in the frame to
generate a deflection in the radial direction; an elastic member
contacting the front side of the piezoelectric ceramic, a part of
the elastic member inserted into the frame and another part of the
elastic member protruding from the front side of the frame, and the
protruded part having a smaller diameter than that of the part
inserted into the frame and vibrating due to ultrasonic waves
applied to the piezoelectric device; a fixed body to fix the
elastic member to the frame, and through which the elastic member
penetrates; and the fluid holes formed in the vicinity of the frame
to penetrate the front side to the rear side of the case.
[0020] The ultrasonic piezoelectric pump further comprises a
distance adjusting circular ring provided in the fluid pipe to
adjust a distance between the piezoelectric actuator and the
tapered nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other aspects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0022] FIG. 1 is a sectional view illustrating an ultrasonic
piezoelectric pump according to an embodiment of the present
invention;
[0023] FIG. 2 is a perspective view illustrating an actuator in
FIG. 1;
[0024] FIGS. 3 to 5 are sectional views illustrating a
piezoelectric device in FIG. 1;
[0025] FIG. 6 is a sectional view illustrating an ultrasonic
piezoelectric pump according to another embodiment of the present
invention;
[0026] FIG. 7 is a sectional view illustrating an ultrasonic
piezoelectric pump according to still another embodiment of the
present invention;
[0027] FIG. 8 is a perspective view illustrating an actuator in
FIG. 7;
[0028] FIG. 9 is a perspective view illustrating another example of
the actuator in FIG. 7;
[0029] FIG. 10 is a sectional view illustrating an ultrasonic
piezoelectric pump according to still embodiment of the present
invention;
[0030] FIG. 11 is a sectional view illustrating a piezoelectric
device in FIG. 10;
[0031] FIG. 12 is a waveform chart illustrating a voltage applied
to the piezoelectric device according to an embodiment of the
present invention; and
[0032] FIG. 13 is a conceptual view illustrating a conventional
piezoelectric pump.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the accompanying
drawings.
[0034] FIG. 1 is a sectional view illustrating an ultrasonic
piezoelectric pump according to a first embodiment of the present
invention. The ultrasonic piezoelectric pump includes a fluid pipe
1, a piezoelectric pump 2, a controller 3, and a tapered nozzle
4.
[0035] The fluid pipe 1 has a hollow part 11 formed therein through
which a fluid flows from a fluid source.
[0036] Moreover, the piezoelectric actuator 2 is inserted into the
hollow part 11 and includes a piezoelectric device 23 and a
plurality of fluid holes 24.
[0037] FIG. 2 is a perspective view illustrating the piezoelectric
actuator of FIG. 1. The actuator 2 includes a case 21 with
through-holes 211 formed at the center thereof, a frame 22,
inserted into the through-holes 211, in which the piezoelectric
device 23 is installed to the front side of the frame 22, and the
plurality of fluid holes 24 formed in the vicinity of the frame 22
to penetrate the front side to the rear side of the case 21 and to
permit the fluid supplied to the fluid pipe 1 to flow
therethrough.
[0038] In this case, the piezoelectric device 23, as illustrated in
FIG. 3, is made in the form of a unimorph having a thin plate 231
and a piezoelectric ceramic 232 contacting one side of the thin
plate 231, but may be made in the form of a bimorph, as illustrated
in FIG. 4, having a thin plate 231 and piezoelectric ceramics 232
contacting sides of the thin plate 231.
[0039] The controller 3 is connected to the piezoelectric device 23
through a lead wire 31 to apply a driving power to the
piezoelectric device 23.
[0040] The tapered nozzle 4 has a tapered opening 41 inserted into
the hollow part 11 in front of the piezoelectric actuator and
tapered forward and downwardly. Since the opening 41 is tapered
forward and downwardly, the fluid can be easily discharged and has
difficulty to flow backward so that the backflow of the fluid can
be prevented.
[0041] FIG. 5 is a sectional view illustrating an ultrasonic
piezoelectric pump according to a second embodiment of the present
invention. Hereinafter, structures and operations of the same
components as those of FIG. 1 will be omitted.
[0042] Referring to FIG. 5, a distance adjusting circular ring 5 is
provided in the hollow part 11 of the fluid pipe 1 between the
piezoelectric actuator 2 and the tapered nozzle 4 to adjust a
distance from the piezoelectric actuator 2 and the tapered nozzle
4.
[0043] In this case, the distance between the piezoelectric
actuator 2 and the tapered nozzle 4 is preferably adjusted by the
distance adjusting circular ring 5 to optimize the transmission of
kinetic energy of the fluid.
[0044] FIG. 6 is a sectional view illustrating an ultrasonic
piezoelectric pump according to a third embodiment of the present
invention, and structures and operations of the same components as
those of the first and second embodiments of the present invention
will be omitted.
[0045] According to this embodiment, the ultrasonic piezoelectric
pump includes a fluid pipe 1, a piezoelectric actuator 2, a
controller 3, and a tapered nozzle 4.
[0046] FIG. 7 is a perspective view illustrating the actuator in
FIG. 6, and as illustrated in FIGS. 6 and 7, the actuator 7
includes a case 21, a cylinder 25, a rear plate 26, a front plate
27, and a piezoelectric device 23.
[0047] The case has a through-hole 211 formed at the center and the
cylinder 25 has a pipe shape and is inserted into the through-hole
211.
[0048] Moreover, the case 21 has a plurality of fluid holes 24
penetrating from the front side of the case 21 to the rear side
thereof in the vicinity of the cylinder 25 to permit the fluid to
flow from the front side to the rear side of the case 21.
[0049] The rear plate 26 is fixed to the rear side of the cylinder
25 to close the rear side of the cylinder 25 and the front plate 27
contacts the inner wall of the cylinder 25 and plays a role of a
reciprocating piston.
[0050] The piezoelectric device 23 connects the rear plate 26 to
the front plate 27 and a plurality of piezoelectric ceramics 232
are laminated on the piezoelectric device 23 such that the
piezoelectric device 23 plays a role of a rod for moving the front
plate 27 forward and backward due to an external applied
voltage.
[0051] Moreover, a distance adjusting circular ring 5 is provided
in the hollow part 11 of the fluid pipe 1 between the piezoelectric
actuator 2 and the tapered nozzle 4 to adjust a distance between
the piezoelectric actuator 2 and the tapered nozzle 4.
[0052] FIG. 8 is a sectional view illustrating another example of
the actuator in FIG. 6. Referring to FIGS. 6 to 8, a circular
rubber ring 271 is provided to the front plate 27 to seal the case
to prevent a fluid from entering.
[0053] By doing so, the fluid flowing from the hollow part of the
fluid pipe 1 to outside the case 21 is prevented from entering the
actuator.
[0054] The controller 3 is connected to the piezoelectric device 23
by the lead wire 31 to apply a driving power to the piezoelectric
device 23.
[0055] Meanwhile, the tapered nozzle 4 is inserted into the hollow
part 11 in front of the piezoelectric actuator and has an opening
41 tapered downwardly and forwardly. Since the opening 41 is
tapered forward and downwardly, the fluid is easily discharged and
has difficulty to flow backward so that the fluid can be prevented
from flowing backward.
[0056] The fluid is pumped using the ultrasonic piezoelectric pump
according to the first to third embodiments of the present
invention by adjusting the voltage applied to the piezoelectric
device 23 such that the voltage, as illustrated in FIG. 9, has a
waveform of a voltage slowly increasing during the suctioning of
the fluid and quickly decreasing during the discharge of the
fluid.
[0057] In other words, the frequency of the voltage is adjusted to
have a waveform of the voltage such that the piezoelectric device
is quickly deformed to discharge the fluid and slowly returns to
suction the fluid, therefore the fluid can be smoothly
discharged.
[0058] According to the embodiments of the present invention, the
ultrasonic piezoelectric device (?) transmits kinetic energy to
fluid particles such that the fluid particles flow due to an
inertial force.
[0059] In other words, the movement of the fluid caused by the
inertial force resonates in association with the flow frequency of
the fluid so that heat transfer can be accelerated.
[0060] FIG. 10 is a sectional view illustrating an ultrasonic
piezoelectric pump according to a fourth embodiment of the present
invention. The ultrasonic piezoelectric pump includes a
piezoelectric pump 1, a piezoelectric actuator 2, a controller 3,
and a tapered nozzle 4.
[0061] The fluid pump 1 has a hollow part 11 formed therein through
which a fluid flows from a fluid source.
[0062] Moreover, the piezoelectric actuator 2 is inserted into and
fixed in the hollow part 11, and has a piezoelectric device 23 and
a plurality of fluid holes 24.
[0063] Here, the actuator 2 includes a case 21 having a
through-hole 211 formed at the center, a frame 22, inserted into
the through-hole 211, to which the piezoelectric device 23 is
installed, and a plurality of fluid holes 24 formed in the vicinity
of the frame 22 to penetrate the front side to the rear side of the
case 21 and to permit the fluid supplied to the fluid pipe 1 to
flow therethrough.
[0064] The piezoelectric device 23 may include a multi-layer
piezoelectric disc having a plurality of thin piezoelectric
ceramics 232 which resonate in the thickness direction by the
application of ultrasonic waves.
[0065] Moreover, the controller 3 is connected to the piezoelectric
device 23 by a lead wire 21 to adjust a frequency applied to the
piezoelectric device 23.
[0066] In other words, the controller 3 applies ultrasonic waves
higher than 5 MHz to the piezoelectric device 23 having several
tens of piezoelectric ceramics 232 through the lead wire 31 so that
vibration in the thickness direction is obtained to discharge the
fluid through the tapered nozzle 4.
[0067] Here, a distance adjusting circular ring 5 may be provided
in the hollow part 11 of the fluid pipe 1 between the piezoelectric
actuator 2 and the tapered nozzle 4 to adjust a distance from the
piezoelectric actuator 2 and the tapered nozzle 4.
[0068] FIG. 11 is a sectional view illustrating an ultrasonic
piezoelectric pump according to a fifth embodiment of the present
invention and FIG. 12 is an enlarged view illustrating the
piezoelectric device 23 in FIG. 23. Referring to FIG. 11, the
ultrasonic piezoelectric pump includes a fluid pipe 1, a
piezoelectric actuator 2, a controller 3, and a tapered nozzle
4.
[0069] Here, the piezoelectric actuator 2 includes a case 21 with
through-holes 211 formed at the center thereof, a frame 22 inserted
into the through-holes 211, the piezoelectric device 23 installed
in the frame 22, and a plurality of fluid holes 24 formed in the
vicinity of the frame 22 to penetrate the front side to the rear
side of the case 21.
[0070] The piezoelectric device 23 includes a piezoelectric ceramic
232a, an elastic member 232b, and a fixed body 234.
[0071] Here, the piezoelectric ceramic 23a is provided in the frame
22 and generates deflection in the radial direction.
[0072] The elastic member 232b contacts the front side of the
piezoelectric ceramic 232a, is partially inserted into the frame
22, and is partially protruded outwardly from the front side of the
frame 22.
[0073] The part of the elastic member 232b protruded from the frame
22 has a diameter smaller than that of the part of the elastic
member 232b inserted into the frame 22, and due to the small
diameter, generates a large deflection.
[0074] The elastic member 232b vibrates at ultrasonic waves with a
preset frequency applied to the piezoelectric ceramic 232a in the
longitudinal direction.
[0075] In other words, the elastic member 232b does not vibrate
when the frequency applied to the piezoelectric ceramic 232a is
low, but vibrates in the longitudinal direction by which ultrasonic
vibration is transmitted thereto when the frequency applied to the
piezoelectric ceramic 232a is in the form of ultrasonic waves with
several hundreds of kHz or higher.
[0076] Meanwhile, the elastic member 232b is inserted into the
fixed body 234 to penetrate the same, and the fixed body 234 fixes
the elastic member 232b to the frame 22.
[0077] The controller 3 is connected to the piezoelectric device 23
by the lead wire 31 to adjust the frequency applied to the
piezoelectric device 23.
[0078] In the fifth embodiment of the present invention, the
intensity of the frequency applied to the piezoelectric device by
the controller 3 is set by modes to vibrate only the piezoelectric
ceramic 232a generating a radial directional deflection or to apply
a higher frequency to vibrate the piezoelectric ceramic 232a and
all the piezoelectric ceramics 232a generating the longitudinal
deflection.
[0079] As such, according to the embodiments of the present
invention, the fluid is pumped using the piezoelectric actuator
installed at the center of the fluid pipe and the tapered nozzle
tapered forward and downwardly without a check valve so that the
fluid is smoothly pumped. Moreover, since the ultrasonic
piezoelectric pump does not include the fluid pipe separated from
the fluid pump and a check valve, the ultrasonic piezoelectric pump
can be made in a simple structure and is easily made in a small
size.
[0080] Meanwhile, although the ultrasonic piezoelectric pump is
described for use with a fluid, the ultrasonic piezoelectric pump
can be used for gas such as air and its description will be omitted
since the structure and operation thereof is identical to the case
of for use with the fluid.
[0081] As described above, according to the ultrasonic
piezoelectric pump, the piezoelectric actuator is installed at the
center of the fluid pipe, a plurality of fluid-flow holes is formed
around the piezoelectric actuator, and the tapered nozzle is
tapered forward and downwardly in front of the piezoelectric
actuator to force the fluid to be easily discharged and to have
difficulty flowing backward so that the fluid can be smoothly
pumped by the piezoelectric actuator without a check valve while
preventing the fluid from flowing backward and the pumping
efficiency can be improved.
[0082] Moreover, a voltage applied to the piezoelectric device is
adjusted to quickly deform the piezoelectric device for the fluid
discharge and a frequency is adjusted to have a voltage waveform to
force the piezoelectric device to be restored slowly so that a
fluid can be smoothly discharged.
[0083] According to the ultrasonic piezoelectric pump, the
piezoelectric device is driven by ultrasonic waves to force the
fluid to flow while causing flow resonance so that efficiency of
heat transfer can be improved.
[0084] According to the ultrasonic piezoelectric pump, the flow of
a fluid is controlled by the piezoelectric ceramic vibrating in the
longitudinal direction or in the radial direction by the
application of ultrasonic waves and the elastic member vibrating in
the longitudinal direction by ultrasonic waves applied to the
piezoelectric device, so that the fluid can be smoothly pumped
without the backflow by the piezoelectric actuator without a check
valve and the ultrasonic piezoelectric pump can be applied to small
sized products.
[0085] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *