Dispensing pump for media of low viscosity, especially paste-like media

A dispensing pump (1) made of plastic for dispensing metered amounts of paste-like media includes a bottle-, can- or tube-like container (60), with an elastic bellows (4) acting as a pumping member, which is connectingly arranged between an upper housing part (2) and a telescopingly movable, lower housing part (3), which is coaxial thereto, and whose interior (32) forms a pump chamber. Its upper end section (38) is connected to an annular wall (35) of the upper housing part (2). Its lower end section (45) is in sealing contact with an annular shoulder (46) of a radial partition (19) of the lower housing part (3). A second pump chamber (33, 33/1 ) for a second medium, which communicates with the discharge opening (10) of the upper housing part through a second discharge valve and/or at least one flow opening (34) in the partition (13), is formed by two annular wall sockets (30, 31 ), which are telescopingly guided one inside the other, concentrically surround the bellows (4) at a radially spaced location, and are made in one piece with one of the two housing parts (2, 3) each. On the suction side, the second pump chamber is connected to an annular chamber (81) of a container (61) or to a second container via at least one eccentric suction channel (82) in the radial wall (19).

FIELD OF THE INVENTION 
The present invention pertains to a dispensing pump made of plastic for 
dispensing metered amounts of media of low viscosity, especially 
paste-like media from a bottle-, can-, or tube-like container, with an 
elastic bellows acting as a pumping member, which is connectingly arranged 
between a dimensionally stable, upper housing part and a lower, likewise 
dimensionally stable housing part, which is coaxial thereto and is 
telescopingly movable, and whose interior forms a pump chamber, through 
which the medium is pumped, wherein its upper end section is in sealing 
contact with an annular wall of a radial intermediate wall of the upper 
housing part, which intermediate wall is provided with at least one paste 
flow opening and/or one discharge valve, and its lower end section is in 
sealing contact with an annular shoulder of a radial partition of the 
lower housing part, and wherein the lower housing part has a discharge 
opening, and the lower housing part is provided with a suction valve, 
which connects the container to the pump chamber, as well as with a 
suction tube socket, by which the suction valve is or can be connected to 
the container. 
BACKGROUND OF THE INVENTION 
A dispensing pump of this type has been known from, e.g., West German 
Utility Model No. DE-Gbm 88,00,880.0. The partition of the upper housing 
part, which is telescopingly guided in the lower housing part, is provided 
there with a pipe socket, which is directed in the downward direction 
toward the partition and the suction valve, and is surrounded by a 
reinforced annular shoulder of the bellows. This pipe socket is provided 
on its top side with a conical valve seat annular surface, on which a 
closing member is elastically seated, and the said closing member is 
elastically supported at the closing front wall of the upper, two-part 
housing part, and is movably guided in the pipe socket by means of an 
axial cross rib. The upper housing part consists of two hollow bodies, 
which are lockingly connected to one another, and one of which has a 
cylindrical guide wall, with which it is axially movably guided in the 
lower housing part between two end positions. The second hollow body of 
the upper housing part, which is lockingly inserted into a projecting 
cylindrical wall section above the partition, has an eccentric, 
channel-like discharge opening, which extends axially parallel and is in 
direct connection with a hollow space, in which the closing member of the 
discharge valve is arranged, and which is also connected, via this 
discharge valve, to the interior of the bellows, while the upper housing 
part as a whole moves in relation to the lower housing part, performing a 
delivery stroke in the downward direction. 
Even though it is possible, in principle, in this type of dispensing pump 
(to which also corresponds, e.g., the dispensing pump according to 
EP-A-0,194,417, and which have a bellows as a pumping member), to draw in 
two or more different media simultaneously from separate containers, the 
mixing of these media is uncontrollable, because all the media drawn in 
simultaneously flow through the same pump chamber. 
A paste dispenser has also been known (U.S. Pat. No. 4,438,781), but it has 
no bellows as the pumping member, but two pump plungers, which can be 
actuated manually and draw two media simultaneously, in cooperation with 
suction valves, from two paste containers, which are located 
concentrically one in the other, but are separated from each other, and 
are provided with a follower plunger each, and deliver them via separate 
channels into a storage space, which is arranged directly in front of a 
discharge opening. This storage space surrounds a plunger-like closing 
member, which is arranged at an elastic diaphragm wall, to which the 
delivery pressure of the medium is admitted. 
The two pump plungers are arranged coaxially to one another, are rigidly 
connected to one another, and are provided with a common actuating member, 
which is actuated manually. To pump different amounts, the pump plungers 
have different diameters. The likewise coaxial, cylindrical pump chambers, 
which communicate with the separate paste containers via suction valves, 
are connected via separate discharge valves to two separate guide 
channels, which, extending approximately axially parallel, are arranged 
eccentrically to the pump chambers, and open into the storage space. 
This leads to a labyrinth-like shape of the space of the pump chambers 
connected to each other and of the guide channels, which is difficult and 
expensive to prepare, so that it is unsuitable for mass production, 
especially in the case of a so-called disposable article. 
SUMMARY AND OBJECTS OF THE INVENTION 
The basic object of the present invention is to provide a dispensing pump 
of the type described above--while maintaining the simplicity of 
manufacture, which arises especially from the use of a bellows as a 
pumping member--with a second pump chamber, by which a second medium can 
be delivered, simultaneously with a first medium and separate therefrom, 
from a separated container space of the same container or from a second, 
separate container, to a common or separate discharge opening. 
This object is attained by a second pump chamber for a second medium being 
formed by two annular wall sockets, which concentrically surround the 
bellows at a radially spaced location therefrom and are each made in one 
piece with one of the two housing parts, wherein the second pump chamber 
communicates through a second discharge valve and/or at least one flow 
opening in the partition with the discharge opening, and which is 
connected on the suction side, via at least one eccentric suction channel 
in the partition of the lower housing part, to an annular space of the 
container, which annular space surrounds the suction socket, or to a 
second container. 
In the dispensing pump according to the present invention, the bellows acts 
as a single pumping member simultaneously in two separate pump chambers, 
by which metered amounts of two media can be pumped separately at 
different quantity ratios and delivered to separate discharge openings. It 
is possible to influence or change the quantity ratio of the two media by 
varying the volumes of the pump chambers as well as the cross section 
ratios of the suction openings, on the one hand, and the discharge-side 
flow cross sections, on the other hand. 
Another advantage of the dispensing pumps according to the present 
invention is mainly the fact that no additional individual parts are 
needed for forming the second pump chamber, but the means used is formed 
of shaped elements, which are made in one piece with components already 
present, and another important advantage can be considered to be the fact 
that assembly is not rendered more expensive by the added shaped elements. 
While the advantageous embodiments of the invention relating to flow 
openings and partitions and other structural components, contribute to 
achieving a simple, easy-to-mount and functionally reliable shaping, the 
embodiments of the invention including annular channels connected to a 
discharge channel and other similar structure, make it possible, in an 
advantageously simple manner, to the dispensing pump for the simultaneous 
removal of two media, e.g., at a ratio of 1:1 or at a different quantity 
ratio, from two separate containers, to which the dispensing pump can be 
connected in a likewise simple manner. However, it is also possible to 
pump only one medium from one container with the dispensing pump according 
to the present invention, in which case it is completely irrelevant that 
one of the two pump chambers remains inoperative. 
A further embodiment is proposed including a variant with discharge opening 
and discharge channel wherein the upper housing part is subdivided by a 
partition into two compartments, providing advantageous design 
possibilities for the discharge channel and the discharge opening, 
respectively. 
It is a further object of the invention to provide a paste dispenser which 
can dispense paste from two different sources and which dispenser is 
simple in design, rugged in construction and economical to manufacture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The paste dispenser shown in FIGS. 1 and 1a has as the head part an 
integrated dispensing pump 1. This dispensing pump is essentially 
comprised of two cylindrical housing parts 2 and 3, a bellows 4, a suction 
valve 5, and a discharge valve 6. While the two housing parts 2 and 3 
consist of a hard, dimensionally stable plastic, the bellows 4 consists of 
a softer, elastic plastic, which is also able to generate the restoring 
forces that are necessary for the pumping process for the housing part 2 
in relation to the housing part 3. The dispensing pump 1 is provided with 
an easy-to-remove protective cap 7, which is to be removed for use. 
The housing part 2 consists of a cylindrical housing lower part 8 and a 
housing upper part 9, which is connected thereto in a positive-locking and 
non-positive manner and has a discharge opening 10, which forms the outer 
end of a discharge channel 11. The housing upper part 9 is provided with 
an oblique cover wall 12, which is ribbed on its top side, and with which 
an essentially cylindrical chamber wall 14, which is seated on a partition 
13 of the housing upper part 8, is made in one piece. The chamber wall 14 
surrounds a discharge chamber 15, which communicates with the discharge 
channel 11, and is in turn surrounded by a likewise cylindrical annular 
channel wall 21, which surrounds an annular channel 22, which communicates 
with the discharge channel 11 via two lateral openings 23 and 24. The 
annular channel wall 21 is also sealingly seated on the partition 13. As 
is apparent from FIG. 7, the discharge channel 11 and the discharge 
opening 10 have the cross-sectional shape of an elongated hole, which is 
horizontal in the vertical position of the axis of symmetry 1', and is 
defined by two semicircles 10/1, 10/2 and by two parallel walls 11/1, 11/2 
connecting same. The inner sides of the semicircles 10/1, 10/2 are 
provided with axially parallel guide ribs 57 each, which form striping 
channels 58, through which the second medium is added in a the form of a 
strip to the strand of the first medium being dispensed. 
With a lower, cylindrical guide section 16, the housing lower part 8 
extends into a guide cylinder 17 of the housing part 3, so that it is 
movable by an axial stroke H between an inner annular rib 18 of the guide 
cylinder 17 and a radial wall 19 of the housing part 3. 
Above the cylindrical wall section 9' provided with a circumferential 
locking rib 27 and an annular shoulder 29 seated on the upper surface 28 
of the outer wall 25, the housing upper part 9 shown as an individual 
component in FIGS. 5, 6, and 7 is provided with wall sections of different 
shapes, which are essentially aligned with the discharge opening 10 or the 
discharge channel 11 extending obliquely to the center line 1' at an angle 
of ca. 45.degree.. 
Above a the radial partition 13, the outer wall 25 of the housing lower 
part 8 is provided with an inner, circumferential locking groove 26, which 
is used to lockingly accommodate the locking rib 27 of the housing upper 
part 9. 
A cylindrical annular wall socket 30, which sealingly and telescopingly 
accommodates a likewise cylindrical, upwardly directed annular wall socket 
31, which in turn is made in one piece with the radial wall 19 of the 
lower housing part 3, is made in one piece with the underside of the 
partition 13 and concentrically to the bellows 4. The internal diameters 
of the two annular wall sockets 30 and 31 are selected to be such that 
they are located at a certain radially spaced location from the 
circumference of the bellows 4, thus forming a second, annular pump 
chamber 33 with the bellows 4. The first pump chamber 32 is formed by the 
hollow space of the bellows 4 in the known manner. 
The second pump chamber 33 communicates with the annular channel 22 through 
a plurality of axially parallel flow openings 34 of the partition 13, 
which are arranged in a distributed pattern. 
A conical valve seat annular surface 20, which is joined by a cylindrical 
pipe socket 35 directed in the downward direction, is located in the 
center of the partition 13. The pipe socket 35 is surrounded, at a 
certain, radially spaced location, by an annular wall 36, which is open at 
the bottom, and on which an upper annular front wall 37 of the bellows 4 
is supported. In its center, the front wall 37 has a collar 38, which 
sealingly surrounds the pipe socket 35. 
The discharge valve has a closing cone as an axially movable closing member 
39, which is designed as a hollow body, is guided in the cylindrical pipe 
socket 35 by means of an axial cross rib 40, and is provided, at its upper 
end, with an axially elastic annular shoulder 41, which is in elastic 
contact with the flat lower edges 42 of a plurality of radial ribs 43 of 
the housing upper part 9, and which sealingly presses the lower delimiting 
edge 44 of the closing member 39 against the valve seat annular surface 
20. The annular shoulder 41 has openings, not visible in the drawing, 
through which the medium is able to flow axially. 
The lower end of the bellows 4 has an annular wall 45, which sealingly 
surrounds a cylindrical wall 46 of a concentric, pot-shaped mounting 
socket 47, which projects in the direction of discharge. The mounting 
socket 47 has, on the one hand, an annular front wall 48, with which a 
downwardly directed connection piece 49 is made in one piece. The 
connection piece 49 has a cylindrical inner surface 50 and a downwardly 
conically tapering, outer jacket surface 51. An axially movable closing 
member 52 of the suction valve 5, which lies on a likewise conical valve 
seat surface 54 with a conical closing disk 53, is seated in the 
connection piece 49. The closing member 52 is provided, on the underside 
of the closing disk 53, with a cross rib 55, by which it is guided at the 
cylindrical inner surface 50 of the connection piece 49. A total of three 
holding fingers 56, which prevent the closing member 52 from falling out, 
are arranged on the top side of the annular front wall 48 of the mounting 
socket 47. 
A preferably cylindrical enveloping body or an enveloping body of 
elliptical cross section, which is used to completely accommodate a paste 
container 61 provided with a fitting cross-sectional shape, and which has 
a thickened, circumferential edge bead 62 at its lower end, is made in one 
piece with the housing part 3 under the radial wall 19. The relatively 
thin-walled paste container 61 is provided with a follower plunger 64 
introduced into its open lower end 63, and it has, at its the lower end 
63, an annular shoulder 68, which forms an annular groove 67 with the 
slightly conically expanding end section 65 of its enveloping wall 66, and 
is provided with an inwardly directed, upper peripheral edge 69. As a 
result, the thickened edge bead 62 of the enveloping body 60 can be 
lockingly introduced into the annular groove 67 when the paste container 
61 is pushed into the enveloping body 60 from below. Due to the edge bead 
62 and the annular shoulder 68, the lower ends of the enveloping body and 
of the paste container 61 each have increased dimensional stability, which 
facilitates handling to the extent that no particular care must be taken 
to avoid accidental deformations during the introduction and removal of 
the paste container 61 into and from the enveloping body 60. 
At its top end, the paste container 61 (FIG. 3) has, at a front wall 71, a 
collar 72 projecting against the suction valve 5 of the dispensing pump 1. 
The collar 72 is provided with an inwardly directed sealing ring 74, which 
is made in one piece with a front wall ring 73, and on which a pot-shaped 
cutoff closure 76 is integrally cast via a thin, annular cutoff web 75 
(FIG. 3). 
To automatically separate the cutoff closure 76 from the sealing ring 74 
when the paste container 61 is pushed completely into the enveloping body 
60 of the dispensing pump 1 and to push it completely into the interior of 
the paste container 61, in order for a discharge opening to be formed for 
the paste contained in the paste container 61, an opening plunger 78, 
which separates the cutoff closure 76 from the sealing ring 74, is made in 
one piece with the lower front side of the connection piece 49 of the 
housing part 3 via a plurality of axial supports 77 arranged in a 
distributed pattern. The opening plunger 78 is provided with a plurality 
of pressing fingers 79, which separate the cutoff closure 76 from the 
sealing ring 74 during the introduction of the collar 72 of the paste 
container 61 into the mounting socket 47 of the housing part 3, and push 
it into the interior of the paste container 61, as is shown in FIGS. 1 and 
1a. 
A cylindrical suction socket 80 is made in one piece with the front wall 71 
of the paste container 61 as a projection of the collar 72 directed 
downward into the interior of the container. The annular chamber 81 
surrounding the suction socket 80 is provided to receive a second medium, 
which is to be pumped into the discharge channel 11 through the second 
pump chamber 32, the flow openings 34, and the annular channel 22. The 
radial wall 19 of the housing part 3 is provided for this purpose with one 
or more, preferably three, suction channels 82, which are arranged in the 
radial area located between the wall 46 and the annular wall socket 31, 
and open into the second pump chamber 32. The suction channels 82 are 
extended in the downward direction by sleeve-like projections 83, which 
are also used to pierce cutoff closures 84 of the front wall 71, which are 
arranged eccentrically outside the suction socket 80 in a correspondingly 
distributed pattern, and to establish the connection to the annular 
chamber 81 of the paste container. 
To facilitate this piercing of the cutoff closures 84, the lower front 
edges of the projections 83 are sharp-edged, and to ensure that the cutoff 
closures 84 are folded to the side at the same time during separation, the 
lower front edges of the projections 83 are designed as obliquely 
extending projections. 
Due to the opening plunger 78 being connected by the axial webs 77 to the 
connection piece 49, the paste located in the paste container 61 is able 
to flow nearly unhindered into the connection piece 49 and can be drawn 
through same into the interior of the bellows 4, while the housing part 2 
is again moving in the upward direction after a downwardly directed stroke 
movement. At the same time, a substantially smaller amount of the second 
medium is drawn from the annular chamber 81 into the second pump chamber 
33, which has a smaller volume. 
An elastic, annular valve lip 85, which prevents the medium from flowing 
from the second pump chamber 33 back into the suction channels 82, but 
permits more of the second medium to flow into the second pump chamber 33 
during the suction process, is preferably made in one piece with the 
circumference of the lower, cylindrical end section 35 of the bellows 4 to 
ensure valve-like closing of the suction channels 82 or to form a second 
suction valve 5' for the second pump chamber 33. 
However, it is also possible to omit the valve lip 85. At any rate, this 
makes it necessary to make the overall flow cross section of the suction 
channels 82 smaller than the total flow cross section of the flow openings 
34 of the partition 13 of the upper housing part 2, so that a sufficient 
dynamic pressure, which is able to bring about delivery of the second 
medium through the flow openings 34 and the annular channel 22 to the 
discharge channel 11, is generated in the second pump chamber 32 during 
the downwardly directed working stroke of the upper housing part 2. 
In the embodiment of the dispensing pump 1 shown in FIG. 4, the flow 
openings 34 of the partition 13 are covered on the top side by an elastic 
annular lip 34/1 in the manner of a directional valve; the annular lip 
34/1 thus forms a second discharge valve 6'. The annular lip 34/1 is 
located under the annular channel wall 21 on the front side, and is 
centered thereon by means of an inner centering projection 34'. 
To ensure that the smallest possible residual amount of paste remains in 
the paste container 61 when the follower plunger 64 has reached the top 
front at axial cross rib 40, the radial wall 91 of the follower plunger 64 
is provided in its center with an annular depression 92, into which the 
suction socket 80 and the opening plunger 78 and possibly also the 
separated cutoff closure 76 can dip. 
FIGS. 8 through 11 show another paste dispenser, in which an enveloping 
body 60/1, which simultaneously replaceably accommodates--directly next to 
each other in the parallel position--two cylindrical, cartridge-like paste 
containers 61/1 and 61/2, which are provided with follower plungers 101, 
is made in one piece at an elongated oval partition 100 of a lower housing 
part 3/1. According to the cross-sectional shape shown in FIG. 9, the 
enveloping body 60/1 has two semicircular wall sections 107, 108, which 
are arranged symmetrically in relation to an axis of symmetry 106, and 
which are connected to one another by straight wall sections 109, 110 that 
are parallel to each other. 
The two paste containers 61/1, 61/2 may, but do not have to, have the same 
shape. Their the upper front walls 102, 103 are provided with the 
cylindrical connection openings 104, 105 each, which are arranged near the 
edge, i.e., eccentrically, and which are closed in the original state by 
closing covers that can, e.g., be broken off or be pushed into the 
interior of the container. The lower housing part 3/1 of a dispensing pump 
1/1 is made in one piece with the top side of the partition 100, 
eccentrically offset in relation to the axis of symmetry 106, and the 
dispensing pump 1/1 is, in principle, of the same design as the dispensing 
pump 1 of the above-described embodiment. The differences between these 
the two dispensing pumps 1 and 1/1 will be described in greater detail 
below. 
The upper housing part 2/1 differs from the housing part 2 only in that the 
annular wall socket 30/1 forming the second pump chamber 33/1 has a larger 
diameter in order for the second pump chamber 33/1 to have the same pump 
volume as the first pump chamber 32. The lower annular wall socket 31/1, 
which telescopingly and sealingly extends into the upper annular wall 
socket 30/1 and is made in one piece with the top side of the partition 
100, also has a correspondingly larger diameter. 
It is also possible to make two paste containers directly in one piece with 
the partition 100 instead of the enveloping body 60/1 accommodating the 
two separate paste containers 61/1, 61/2. 
It would also be possible to replace the enveloping body 60 (FIG. 1) with a 
paste container made in one piece with the radial wall 19. 
The upper cylindrical end section 38/1 of the bellows 4/1 surrounds an 
annular wall 36/1, which concentrically surrounds the pipe socket 35 at a 
radially spaced location. An upwardly bent, elastic annular lip 112, which 
forms the movable closing member of a second discharge valve 111, and is 
in sealing contact with the inner surface of the annular wall socket 30/1 
in the direction of backflow, is made in one piece with the jacket surface 
of the end section 38/1. 
The lower, cylindrical end section 45/1 of the bellows 4/1 is sealingly 
seated in an upwardly directed annular shoulder 47/1, which forms an 
annular channel 113, which is open at its top, with the annular wall 
socket 31/1 of the partition 100. An upwardly directed annular projection 
114, which is open at the top and acts as a valve seat surface, is located 
within and concentrically to the annular shoulder 47/1, and a cap-like 
valve closing member 115, which is made in one piece with the lower end 
section 45/1 of the bellows 4/1, is elastically and sealingly seated on 
the annular projection 114, and the valve closing member 115 forms, 
together with the annular projection 114, the first suction valve 116 of 
the dispensing pump 1/1, which is located within the bellows. 
The cylindrical hollow space 117 of the annular projection 114 communicates 
with the likewise cylindrical outlet channel 118/1 of a first, eccentric 
suction socket 118, which extends into a connection opening 105 of the 
right-hand 61/2, and which has separated the closing cover (which may have 
been present) of the connection opening 105 during the insertion of the 
paste container 61/2 into the enveloping body 60/1. The annular channel 
113 analogously also communicates with a second suction channel 117/1 of a 
second suction socket 119, which is arranged symmetrically to the suction 
socket 118 in relation to the plane of symmetry 106, and which extends 
into the connection opening 104 of the other paste container 61/1. An 
elastic annular lip, which is made in one piece with the circumference of 
the lower end section 45/1 of the bellows 4/1, is in sealing contact all 
around the inner side of the annular wall socket 31/1, covers the annular 
channel 113, and blocks same in the direction of backflow, acts as a 
second suction valve 120 associated with the second pump chamber 33/1. 
As is apparent from the sectional representation in FIG. 10, the discharge 
channel 111/1 and the discharge opening 110/1 in the embodiment according 
to FIGS. 8 through 10 are provided with a partition 21, which extends in 
parallel to the axis of symmetry 106, i.e., vertically, and which divides 
the discharge channel 111/1 and the discharge opening 110/1 into two 
compartments 111/2 and 111/3 of equal cross section. It is also possible 
here to have the partition 12 1 end within the discharge opening 110/1, so 
that only the discharge channel 110/1 is divided and/or arranged such that 
compartments 111/2 and 111/3 of different cross sections will be obtained. 
It can easily be imagined that the two paste dispensers described operate, 
in principle, in the same manner: Part of the media contained in the two 
pump chambers 31, 33 and 33/1 is delivered to the outside through the 
suction channel 11 and the compartments 111/2, 111/3 of the divided 
discharge channel 111/1 during each downwardly directed working stroke of 
the upper housing part 2 or 2/1, i.e., during each working stroke directed 
toward the radial wall 13 or the partition 100. During the subsequent 
suction stroke, which is brought about by the restoring force of the 
bellows 4 or 4/1, during which the upper housing part 2 or 2/1 returns 
into its upper starting position, the two media contained in the paste 
containers are drawn from the annular chamber 81 and the rest of the 
hollow space of the annular shoulder 41 or from the two paste containers 
61/1 and 61/2 into the pump chambers 32, 33 or 33/1, in the same way as 
they were discharged before during the working stroke. The amounts pumped 
through the two pump chambers 32, 33 or 32, 33/1 are adjusted to the 
quantity ratios at which the two media are actually available. 
The existing quantity ratio of one medium to the other is about 1:10 in the 
paste container 61; the ratio of the amounts pumped by the two pump 
chambers 32 and 33 also corresponds to that ratio. In contrast, the 
quantity ratio of medium A to medium B equals 1:1 in the case of the two 
paste containers 61/1 and 61/2 of equal size, so that the volumes pumped 
through the two pump chambers 32 and 33/1 are also equal. 
The particular advantage of the dispensing pumps 1 and 1/1 according to the 
present invention is mainly the fact that no additional individual parts 
are needed to form the second pump chamber, but the means used consist of 
shaped elements, and the components already present are made in one piece, 
and the circumstance that assembly is not made any more expensive by the 
added shaped elements at all can be considered to be another important 
advantage. 
While specific embodiments of the invention have been shown and described 
in detail to illustrate the application of the principles of the 
invention, it will be understood that the invention may be embodied 
otherwise without departing from such principles.