Note: Descriptions are shown in the official language in which they were submitted.
~lZ14073
HOSE P~MP FOR MEDICAL USES
_ ._
Field of InYe1ltion
.. . .
This invention re1ates to a hose pump. More
particularly, this invention relates to a hose pump for
medical uses.
Back~round of the Invention
s
The supplying of liquids into the body of medical
patients is effected in many instances from a ~upply vessel
from which the liquid runs out by the influence of gravity.
If a higher precision in the rate at which liquid is supplied
is required, or if the delivery pressure from gravity is not
l o
sufficient, positive-displacement pumps are used. The
11
structural parts of such pumps which co~e in contact with the
liquids are, as a rule, made of plastic articles intended for
13
a single use and which are discarded after such use. These
14
plastic articles should be easy and inexpensive to
manufacture. In addition, t;hey should ensure the medically
necessary precision and safety.
18 U.S. Patent No. 2y915~983 discloses a hose pump
wherein a drive shaft is monnted in a housing. The drive
lg
shaft has at its end an eccentrially arranged shaft piece
; extending at an angle. On this shaft piece, a swash plate is
21
mounted which is secured against rotation relative to the
22
housing of the hose pump. 13etween the swash plate and a cover
which closes the housing, a hose section laid in rings is
arranged. The ends of the hose section are passed thro11gh
" slots in the cover. The hose ends are brougllt out Or the
26
cover and are connected with a liquid source and with a user~
27
When the drive shaft rotatei, the swash plate is callsed to
28
29 wobble, pressing a region o;i` the annular hose section against
the cover and squeezing it `lat. The flattened re~ion moves
during the wobble motion, '30 that the liquid contained in the
annular hose section is pushed forward in the hose.
Hose pumps of` thu prior art have the disadvantage
that insertion of the hose is difficult and requires a certain
s~ill. A section of the hose must be laid in the coYer or
respectively over the swasn plate in rings? while the very
long ends are brought out sf openings in the cover. The
diameter of the annular hose section is not fixed~ so that the
position of the annular hose section in the hose pump is
undefined. If the diameter of this annular hose section is
made too large or too small, relative movements between the
11
annular hose section on the one hand and the cover or swash
12
plate on the other hand will occur during the revolving
squeezing by the swash plate. These relative movements lead
14
to increased friction and to wear and loss of output. In
addition with the hose pumps of the prior art, the insertion
16
of the hose requires a cer~ain degree of experience. If the
17
hose is inserted the wrong way, the pump will deliver in the
18
wrong direction.
19
Also known, ls a hose pump (U.S. Patent No.
3,720,489) where a swash plate forms the cover of the housing.
21
22 The annular hose section is installed in an annular groove in
~ the llousing. The swash plate is pressed in the direction of
23
the annular groove by a spring. In this ilose pump also, the
~ hose may be inserted to ary direction with the possibility of
connecting the long hose ends protruding from the housing in
26
any manner. This hose pump also does not provide for simple
27
changing of the hose and (loes not ensure that the hose can be
28 ,
inserted only in a defined position in order to avoid
29
ùnintenJed reversal of the delivering direction.
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~2~0~73
For medical uses, where the hose pu~p is to deliver,
for example, blood or a ser~lm, the hose is used as a
disposable or throw-away ar~icle. Therefore, it must be easy
to remove the hose from the pump and to replace it. Since
incorrect insertion of the hose may, in such applications,
have serious consequences for the patient, it must be assured
that operation of the hose pump is possible only with the hose
inserted correctly.
Ob~ect of the Invention
It is therefore an object of the present invention
to provide a hose pump, particularly for medical uses, where
11
the hose can be replaced in a simple manner and which can be
12
handled without problems, for instance, by the nursing
13
personnel of a hospital or the patient.
14
These and other objects of the present invention
will become apparent from the following description and claims
16
in conjunction with the drawings.
17
Summary of the Invention
18
In accordance with the present invention, the cover
19
of the hose pump has on its underside an annular groove for
securing the annular hose section as well as a clamping means
21
for fixing the hose in the cover. The hose ends are connected
22
with a co~mon coupling piece which is insertable in the cover
23
and has inflow and outflow connections. On the side Or the
24
cover opposite the couplin~; piece, t~le cover is conl)ect.e~i with
25`
the housing by a hinge. A locl;ing device is arra~lgt?~i ncal t.ht?
26
coupling piece for lockin~ the cover in tht? clcsed positio
27
the housing.
28
Brief Description of the Drawings
29
In the drawin~s formin~ part hereof:
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,,
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~2~4~7a
Fig. 1 is a longi~udinal sectional view through a
hose pump in accordance witll one embodiment of the present
invention;
Fig. 2 is a view alon~ line II-II of Fig. l;
Fig. 2a is a sche~natic view of a modified embodiment
of the invention as illustrated in Fig. 2;
Fig. 3 is a partial schematic front view of the hose
pump of the invention from the direction of arrow III in Fig.
. l;
Fig. 4 is a schematic longitudinal sectional view
l o
through the working part of a double hose pump in accordance
11
with another embodiment of the present invention; and,
12
13 Fig. 5 is a schematic view of the cover of the
double hose pump illustrated in Fig. 4 in the open state with
14
the hoses inserted.
Description of the Preferred Embodiments
16
In order to provide a more complete understanding of
17
the present invention and all appreciation of its advantages, a
18
description of the preferred embodiments is presented below.
19
In the hose pump according to the invention, and
with reference to Fig. 1 and Fig. 2, both ends of the hose 26
21
are connected with a common coupling piece 29 which is
22
inserted together with the hose 26 in a recess or annular
23
i groove 31 in the cover 22 of the hose pump. Thus the hcse 26
24
, together with the coupling piece 29 forms a throw-away unit.
25~
; The coupling piece 29 assures that the hose 26 is inserted in
26
the cover 22 in the correct position and direction of
27
delivery. Changing the ho~e 26 is done after the cover 22 has
28
been flapped up about the hinge 31~. Chan6in~ the l~ose 6
29
mere~y requires simple manipulations. A lockin~ device 37 is
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~214073
released and the cover 22 flapped up. Then the hose 26,
together with the coupling piece 29, is removed from the cover
22 and replaced by a new ho~e and coupling piece. The annular
groove 31 brings about the exact positioning of the annular
hose section 26 in the covel 22, so that no major
displacements of the hose 2li ocour in operation. In
particular, frictional stress in the circumferential direction
of the hose is avoided. In;ertion of the hose is facilitated
by the pivotable mounting arrangement of the cover on the
housing. The cover 22 is captive and is guided exactly during
the closing movement. Therefore, shifting of the hose and
11
wedging of the hose durlng losing of the cover is avoided.
12
In hose pumps~ the danger exists that delivery may
13
stop briefly, so that even a drawing back of the liquid occurs
14
if the squeezing element passes over the outlet-side end of
the hose and this end does not subsequently regain the full
16
hose cross-section~ To avoid or at least to reduce the
17
discontinuities caused during the delivery, in accordance with
18
the present invention, two hoses may be arranged side by side
19
in a plane with each hose 26 having its own swash plate 20
assigned to it. (See Figs. 4 and 5). The swash plates 20 are
21
driven by a com~on drive at equal speeds, and the two hoses
22
share a common coupllng pi~ce 29 having a sin~le inflow and a
23
single outflow. In this way, two hose pumps are combined in
24
such a manner that their hc~ses to~ether with the couplin~
piece form a sin~le throw-c;way or disposable unit. The two
26
hoses may be arranged in a common cover~ The swash plates 20
27
of the two hoses are driven phase-shifted or in phase
28
opposition, so that the critical phases of the brief
29
inierruption of the delivery ~o not coincide.
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~14073
In the following the illustrative embodiments of
¦ the invention are explained .~n greater detail with reference
to the drawings.
~' The hose pump illustrateà in Figures 1 to 3
j comprises a housing 10 with a cylindrical bore 11 in which a
sleeve 12 is mounted for lengthwise displacement. In the
interior of sleeve 12, ball bearings 13 support the shaft 14,
l which is driven by an electric motor 15 through a reduction
8,j
gear 16. The drive shaft 17 -~s formed by the output shaft of
the reduction gear 16, and i~ is coupled with shaft 14 via a
fork type coupling 18 in sucl1 a way tl1at shaft 14 can execute
small axial displacements reLative to the output shaft 17.
i At its output end, shaft 14 has an angularly bent
l3'
shaft piece 18, the axis of which forms with the axis of shaft
1' 14 an acute angle alpha ("~"). The swash plate 20 is mounted
15 :'
on this shaft piece 18 through a ball bearing 19. Ball
16il
bearing 19 and swash plate ~0 are contained in a chamber 21
inside the housing 10. This chamber can be closed with the
~I cover 22. In the present e~lbodiment, the swash plate 20
19 ~ .
comprises a ring, the outer end face 23 of which is beveled to
20l
! match the angle alpha. The intersection of the axes of shaft
I 14 and shaft piece 18 lies in the plane of the mean dia~eter
22j
,i "b" of the end face 23 (i.e. of the diameter of the median
¦I circle of the conical surface of the end face 23).
24~1 The ball bearing 9 is n~ounted in the interior of
¦l the ring, the outer end fac of which is sealed ~y a seal disk
27l 24, so that no liquid can p;l-etrate through the a~ial channel
¦1 of the swash plate 20. The inner edge of a ~e~nbrane 25 is
fastened at the circumf~rence of the swash plate 20. T~e
30i outer ed~e Or membrane 25 lS fastened on the sidewall of
lZ14073
~!
` chamber 21 of housing 10~ ~hus the seal disk 24 together
with the membrane 25 forms a liquid-proo~ seal between the
drive ~echanism of swash plate 20 against the sp~ce receiving
the hose 26.
Hose 26 is attached to the underside of cover 22.
With reference to Fi~. 2 hcse 26 is bent or curved in the
6`l
form of a ring with the inlet 27 and the outlet 28 being
! arranged side by side and extending out radially with respect
!j~ to the ring. Inlet 27 and outlet 28 are connected with a
coupling piece 2~ of essentially L-shaped or angle form whose
10 "
inflow nipple 30 and outflow nipple 30 protrude from the
11
cover 22 vertically.
12
Hose 26 is inserted in an annular ~roove 31 on the
13
underside of cover 22. This annular groove 31 is limited
14
j internally by an axially raised projection 32 and externally
by a circlin~ edge 33 of eqlal depth. As can be seen from
16 ',!
Fig. 1 the annular swash p~ate 20 engages into the annular
17
I; groove 31 of cover 22. The depth of penetration of swash
8 !,
1 plate 20 into groove 31 varies over the circumference because
19 '
of the oblique position of swash plate 20. Hose 26 is
; squeezed together in the axial direction between the outer
21
face 23 of the swash plate 20 and the bottom of the annular
22ii
groove 31.
23 ;
ll With referel1ce to Fig. 1~ the Inean diameter a" of
24
¦¦ the annular end face 23 of swash plate 0 is the same as the
¦I mean diameter b of the annulal groove 31 ~hich in turn is
26l;
the mean diameter of the hose ring inst.alled in sroove 31. ~s
27 j
a result the end face 23 executes a pure rollin~ moven1ent in
il ~roove 31 but without turr!ing in this ~roove. If the mtan
li di~eters a and b are dit`ferent the ~wash platæ ~n would
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~2~407a
tend to revolve slowly in the housing about the shaft piece
18. In so doing it would e~ert a shearing action on the hose
26, and this would cause friction losses which reduce the
efficiency.
Cover 22 is fastened to housing 10 by a hinge 34, so
that it can be flapped or pivoted open according to Fig. 2.
The coupling piece 29 is located at the end of cover 22
opposite to the hinge 34. ~t this end an oblong slot 35 is
provided. The hose 26, inserted in cover 22 from below, is
retained by fishplates 36 which partly span the inlet-side end
1 o
and the outlet-side end of hose 26. Between these fishplates
11
36, however, there is a gap which is wide enough for the hose
12
26 to be taken out of cover 22 with relatively slight
13
deformation.
14
The embodiment of the invention illustrated in Fig.
2a corresponds to a large extent to that of Fig. 2. The only
16
difference is that instead of the fishplates 36, which
17
according to Fig. 2 retain the hose 26 in the cover, there is
18
provided at the edge of the oblong slot 35 in cover 22 a
19
semi-cylindrical bulge 36 t which presses one hose end near the
coupling piece 29 in the direction of the other hose end. The
21
hose is thus deformed, both hose ends being slightly
22
compressed and retained in cover 22 by clamping type action.
23
I To lock the cover 22 in the closed position in the
24 i
housing 10, claws 37 are provided at the end of cover 22
i opposite to hinge 34. Thece claws 37 are n~ounted by a hinge
26
pin 38 on cover 22 and are pressed into the locking po~ition
27
by a spring 39. As illustrated in Fie. 2 and Fig. 3, their
28
outer ends 40 engage in lateral recesses in housing 10 to lock
29
cover 22 to housing 10 in the closed position. By laterally
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12~40~3
pressing in the claws 37, their ends 40 are spread apart witl
the springs 39 being compr~ssed. The cover 22 is thereby
unlocked from the housing 10 and can be lifted up.
To place the hose pump into use, first hose 26
together with the coupling piece 29 is inserted in cover 22 in
the manner shown in Fig, 2. Then, cover 22 is closed and
locked on housing 10. As a result, the swash plate 20 is
pressed against hose 26 in its farthest protruding region so
fir~ly that it pinches the hose 26 in the annular groove 31.
A single nip forms along the circumference of the ring formed
by hose 26. This nip is sufficiently long in the
11
circumferential direction that no short circuit develops at
12
the inlet and outlet. Briefly, both hose ends 27 and 28 are
13
pinched jointly. When motor 15 is turned on, shaft 14 rotates
14
and swash plate 20 executes a wobble motion, but without
participating in the rotation. Due to the wobble motion, the
16
point at which maximum compression of hose 26 takes place
17
circles along the ring formed by hose 26 at constant speed.
18
In this way, the liquid contained in hose 26 is pushed forward
19
from the inlet 27 to the outlet 28.
After use, the claws 37 are released and cover 22
21
flapped up. The hose 26 together with the coupling piece 29
can then be removed and replaced.
23
!` The ball bearings 13 and 19 for supporting shaft 14
24'
I and swash plate 20 respèctively not only serve as radial ball
bearings but are also able to transmit axla~ forces~
26
27 Accordingly, the bearing pressure of spring 41 is transmitted
to swash plate 20. Spring 41 is supported on the rear end
wall of housing 10 and pres~es against a ring shoulder 42 of
29
sleeve 12, so t.hat sleeve 12 to~ether with shaft 11~ and the
1~ 07;~
ball bearings 13 and 19 as well as the swash plate 20 are
pressed in the direction of hose 26 or cover 22 by the force
of compressed spring 41. In order to secure sleeve 12 non-
rotationally in housing 10, a radially projecting pin 43
extends through an axial slot 44 in the wall of housing 10 and
into a bore provided in sleeve 12. Pin 43 serves also as axial
stop, so that the swash plate 30 will not fall out of the
!; housing 10 when the cover is open. In addition, when the
cover is closed without a hose placed in groove 31, pin 43
prevents swash plate 20 fro~ coming in contact with the guides
32 and 33 and causing damage.
11
Since that part of the swash plate 20 which projects
12
axially farthest forward anl causes the maximum pinching of
13
the hose 26 revolves on the circle formed by the hose, liquid
14
is transported from the inlet 27 to the outlet 28.
In the embodirnent illustrated in Figs. 4 and 5, two
16
hose pumps are arranged side by side in a common housing 10.
17
The swash plates 20 of both hose pumps are driven in opposite
18
directions and their inlets 27 are connected with one another,
19
as are also their outlets 2~. Preferably, both swash plates
are driven each at the same speed most suitably by a common
21
drive mechanism (not illustrated). The inlets 27 are
22
connected with an inflow 30 of the couplin~ piece 29. The
23
outlets 28 are connected with ~n outflow (not shown) of the
~ coupling piece 29. Referrin~ to Fig. 5, couplin~ piece 29 is
arranged in a gap 45 ln the cover 22 which i.S ope1l on the side
26
of cover 22 opposite to the side where the hi1l~e 34 is
27
located.
28
As is evident from Fig. 4, the two swash plates 20
29
have a relative phase shift of 1~0. While the left swas}
--1 0--
~21407;~
plate 20 executes the strongest pinching of the respective
hose 26 on the side adjacent to the coupling piece 29, the
ri~ht swash plate 20 causes maximum pinching at the same
moment at the point of the respective hose 26 farthest away
from or remote from the coupling piece 29.
In the embodiment of the invention illustrated in
Figs. 4 and 5, the cover 22 receives the two hoses 25, which
jointly lie in a common plclne. Together with the coupling
piece 29 arranged between them, the hoses 26 form a disposable
unit. Because of the phas~shifted drive of the two swash
l o
plates 20, any discontinuities in time of the total delivery
of the hose pump are diminished.
12
13 It will be readi:'y appreciated that the details of
construction of the right and left swash plates 20 and
14
associated mechanisms of the embodiment of Fig. 4 may be
suitably substantially sim:,lar to the details illustrated and
16
described in conjunction w:~th the embodiment of Fig. 1.
17
Although preferrl?d embodiments of the present
18
invention have been descrihed in detail, it is contemplated
19
that modifications may be made within the spirit and the scope
2~
of the invention.
21
22
23
~4
26
27
28
29
