U.S. patent number 3,810,719 [Application Number 05/197,840] was granted by the patent office on 1974-05-14 for pump for discharging a predetermined quantity of fluid.
This patent grant is currently assigned to Papillon Establissement. Invention is credited to Adolf Johan Wolthers.
United States Patent |
3,810,719 |
Wolthers |
May 14, 1974 |
PUMP FOR DISCHARGING A PREDETERMINED QUANTITY OF FLUID
Abstract
A pump for discharging a predetermined quantity of fluid. The
pump housing contains a reciprocating pumping member, which is
preferably driven in a forward stroke by mechanical, hydraulic or
pneumatic means under the control of a solenoid which, when
energized, causes the pumping member to take the forward stroke,
the length of which corresponds to the predetermined quantity of
fluid to be delivered by the pump. The solenoid remains energized
until the forward stroke is completed, at which time it is
deenergized. The stroke length of the pumping member, and hence the
amount of fluid delivered by the pump, is adjustable. The driving
force for the return stroke of the pumping member is preferably
accomplished by means of a spring which is loaded during the
forward stroke, the force of the loaded spring being overcome by
the solenoid as long as the solenoid is energized, or by hydraulic
or pneumatic means controlled by a conventional distribution member
under the influence of the solenoid.
Inventors: |
Wolthers; Adolf Johan (Kaarst,
DT) |
Assignee: |
Papillon Establissement (Vaduz,
FL)
|
Family
ID: |
4424399 |
Appl.
No.: |
05/197,840 |
Filed: |
November 11, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Nov 23, 1970 [CH] |
|
|
17307/70 |
|
Current U.S.
Class: |
417/416; 417/317;
417/403; 92/98D; 417/345 |
Current CPC
Class: |
F04B
9/1115 (20130101); G01F 11/021 (20130101); F04B
49/12 (20130101); F01L 25/08 (20130101) |
Current International
Class: |
G01F
11/02 (20060101); F01L 25/08 (20060101); F04B
9/111 (20060101); F01L 25/00 (20060101); F04B
9/00 (20060101); F04B 49/12 (20060101); F04b
017/04 () |
Field of
Search: |
;92/98D
;417/317,326,402-404,415,416,505,345,347 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Husar; C. J.
Attorney, Agent or Firm: Hubbell, Cohen & Stiefel
Claims
What is claimed is:
1. A pump for discharging a predetermined dosage quantity of a
fluid comprising a pump housing, said housing including a pump
chamber, said chamber having an inlet and outlet passageway in
communication with the exterior of said pump chamber, said inlet
passageway being in communication with a source of said fluid, said
outlet passageway being capable of discharging said dosage
therefrom, distribution means for controlling said fluid inlet and
outlet passageways for controlling the discharge of said fluid, a
reciprocatably movable pumping member within said chamber, means
for reciprocatably driving said pumping member, said driving means
including solenoid means for controlling said reciprocation in
accordance with a state of said solenoid means, said solenoid means
having an excitation state and an excitation interruption state and
controlling the operation of said distribution means in accordance
with said solenoid means state, said solenoid means enabling said
pumping member to be driven from a rest position to a forward
stroke position when said solenoid means is in said excitation
state and to be returned via a return stroke to said rest position
to complete said reciprocation when said solenoid means is in said
excitation interruption state, said pumping member including means
associated therewith for maintaining said solenoid means in said
excitation state at least until said pumping member has been driven
to said forward stroke position, said forward stroke position being
a predetermined distance from said rest position whereby said
pumping member traverses a volume in said chamber corresponding to
said predetermined dosage quantity of fluid, said solenoid means
including a limit switch for switching said solenoid means from
said excitation state to said excitation interruption state when
said limit switch is actuated from a closed position to an open
position, said limit switch being actuated to said open position
when said pumping member reaches said forward stroke position; said
pumping member further including a rod-like member movable in
unison therewith, said rod-like member including a cylindrical
portion having an internally threaded first sleeve co-axial with
and axially adjustable with respect to said rod like member and
having a switching means thereon for actuating said limit switch to
an open position when said first sleeve has travelled in unison
with said pumping member to said forward stroke position of said
pumping member, and a second co-axial sleeve slidably mounted over
said first sleeve so as to be substantially non-rotatable thereon,
said second sleeve including an adjusting knob thereon for
adjusting the axial position of siad first sleeve with respect to
said rod-like member, said second sleeve having a resistance
against rotation greater than any amount of rotation exerted by
said first sleeve upon said actuation of said limit switch to said
open position.
2. A pump in accordance with claim 1 wherein said pump further
includes means for varying the forward stroke position distance so
as to vary the predetermined quantity of fluid to be
discharged.
3. A pump in accordance with claim 1 wherein said drive means
includes a source of pressurized medium, said housing further
including an inlet and outlet passageway in communication with said
pressurized medium source and said pumping member for
reciprocatably driving said pumping member, said distribution means
controlling said pressure medium passageway and said fluid
passageway for controlling the discharge of said fluid.
4. A pump in accordance with claim 1 wherein said drive means
includes resilient means for applying a force to said pumping
member to bias said pumping member toward said rest position, said
drive means including means for overcoming said bias force and
enabling said pumping member to be driven to said forward stroke
position when said solenoid means is in said excitation state, said
bias force driving said pumping member back to said rest position
when said solenoid means is in said excitation interruption
state.
5. A pump in accordance with claim 4 wherein said drive means
comprises hydraulic drive means for overcoming said bias force and
driving said pumping member to said forward stroke position.
6. A pump in accordance with claim 4 wherein said drive means
comprises pneumatic drive means for overcoming said bias force and
driving said pumping member to said forward stroke position.
7. A pump as in claim 1 wherein said second sleeve includes at
least one spring loaded locking means engageable in a recess of a
ring of identical recesses arranged in said pump housing, said
locking means on rotation of said second sleeve successively
engaging each subsequent recess with a snapping action, whereby
said second sleeve resistance against rotation is effectuated.
8. A pump as in claim 1 wherein said pump housing includes at least
one spring loaded locking means engageable in a recess of a ring of
identical recesses arranged in said second sleeve, said locking
means on rotation of said second sleeve successively engaging each
subsequent recess with a snapping action, whereby said second
sleeve resistance against rotation is effectuated.
9. A pump as in claim 1 wherein said limit switch comprises a
contact ring of electrically conductive material arranged around
the second co-axial sleeve, against the periphery of which contact
ring in the closed position of the limit switch bear the
springloaded end contacts of a pair of terminals conducted in an
electrically insulated manner through a wall of the pump housing,
which contact ring can be moved axially by the switching member of
the first co-axial sleeve after a predetermined amount of
resistance against shifting of said ring has been surmounted by
said switching member, the axial pressure exerted by the swtiching
member being transmitted to the contact ring by spring action.
10. A pump as in claim 9 wherein the contact ring is carried by an
annular carrier of electrically insulating material, which carrier
is brought back by a spring into a position in which the limit
switch is closed, the action of which spring is compensated by the
switching member before said switching member opens said
switch.
11. A pump as in claim 9 in which the contact ring is carried by
the second co-axial sleeve made of electrically insulating
material, said second sleeve being axially movable in the pump
housing with such a play, that it can be moved by the switching
member into a position in which the limit switch is open, and is
moved back to its starting position in which said switch is closed
in response to the movement of the pumping member when the pumping
member approaches the end of its return stroke.
12. A pump as in claim 11 in which the contact ring is locked
against rotation with respect to the second co-axial sleeve by
means of V-shaped axial grooves arranged in the periphery of said
contact ring, which grooves are provided each at their bottom with
a recess into which the contacts of the limit switch are snapped in
the closed position of said limit switch, the carrier of the
contact ring being provided with similar grooves in line with the
grooves of the contact ring.
13. A pump as in claim 1 in which the pitch of the screw-thread
joining the first co-axial sleeve to the cylindrical portion of the
rod-like member of the pumping member is at least equal to the
maximum stroke length of the pumping member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pumps for discharging
predetermined quantities of fluids.
2. Description of the Prior Art
To date there are no prior art pumps capable of discharging a
predetermined quantity of a fluid which are of simple construction
and can be manufactured economically. In addition, the dosage
quantity discharged by prior art dosing pumps is not capable of
being predictably varied or adjusted in a simple and efficient
manner.
The present invention overcomes these disadvantages of the prior
art.
SUMMARY OF THE INVENTION
A pump for discharging a predetermined quantity of fluid includes a
pump housing and a reciprocating pumping member therein driven by
either mechanical, hydraulic or pneumatic means which are
controlled by a solenoid in such a manner, that on the energizing
of the solenoid the pumping member carries out one forward stroke
and on the de-energizing of the solenoid the pumping member carries
out the return stroke. The pumping member is preferably locked
against rotation and is cooperatively associated with a rod-like
member moving in unison therewith, the end of which rod-like member
facing away from the pumping member being provided with a
cylindrical portion having at its surface a single or multiplex
screwthread carrying an internally threaded sleeve co-axial with
but axially adjustable to the rod-like member and having a
switching member for opening a limit switch, which switch is
connected in the energizing circuit of the solenoid controlling the
drive of the pumping member, during the travel of the sleeve in
unison with the pumping member so as to interrupt the energizing or
electric circuit and de-energize the solenoid. A second co-axial
sleeve is slidably mounted over the first mentioned co-axial sleeve
but is preferably not rotatable thereon and is preferably
journalled, with some axial play at most, in the pump housing. This
second sleeve carries at its end protruding therefrom an adjusting
knob for adjusting the axial position of the first mentioned
co-axial sleeve with respect to the rod-like member of the pumping
member, the resistance against rotation of the second co-axial
sleeve being larger than the moment of rotation exerted thereon by
the first mentioned co-axial sleeve upon the opening of the limit
switch by the switching member.
According to the invention, the resistance against rotation of the
second co-axial sleeve is preferably effected by at least one
spring loaded locking means carried by the sleeve or by the pump
housing and engaging a recess of a ring of identical recesses
arranged in the pump housing or in the sleeve, respectively, the
locking means on rotation of the sleeve successively engaging each
subsequent recess with a snapping action.
In the preferred embodiment of the invention, in order that a quick
interruption of the electric or energizing circuit of the solenoid
is effected, in spite of the relative slow motion of the pumping
member, so that sparking of the contact parts of the limit switch
is prevented, the switch comprises a contact ring of electrically
conductive material arranged around the second co-axial sleeve, the
spring loaded end contacts of a pair of terminals conducted in an
electrically insulated manner through the wall of the pump housing
bearing against the periphery of the contact ring in the closed
position of the limit switch. The contact ring can be moved axially
by the switching member of the first co-axial sleeve after the
resistance against the shifting of the ring has been surmounted by
the switching member, the axial pressure exerted by the switching
member being transmitted to the contact ring by spring action.
When it is desired to maintain the adjusting knob of a pump fully
stationary, the contact ring is carried by an annular carrier of
electrically insulating material, the carrier being brought back by
a spring into a position in which the limit switch is closed, the
action of the spring being compensated by the switching member
before it opens the switch. However, when movement of the adjusting
knob on interruption of the electric or energizing circuit of the
solenoid over a relatively small distance in the axial direction is
permissible, the contact ring may be carried by the second co-axial
sleeve made of electrically insulating material, this sleeve being
axially movable in the pump housing with such a play, that it can
be moved by the switching member into a position in which the limit
switch is opened, and moved back to its starting position in which
the switch is closed in response to the movement of the pumping
member when it approaches the end of its return stroke.
In a simplified embodiment of the pump according to the invention,
the end contacts of the switch take over the task of the spring
loaded locking members effecting the resistance against rotation of
the second co-axial sleeve. In such an embodiment of the pump, the
contact ring is locked against rotation with respect to the second
co-axial sleeve preferably by means of V-shaped axial grooves
arranged in the periphery of the contact ring. Each of these
grooves is preferably provided at the bottom thereof with a recess
into which the contacts of the limit switch are snapped in its
closed position, the carrier of the contact ring being provided
with similar grooves in line with the grooves of the contact
ring.
BRIEF DESCRIPTION OF DRAWING
FIG. 1 is a longitudinal sectional view of the preferred embodiment
of the pump of the present invention;
FIG. 2 is a cross sectional view taken along line II--II of FIG.
1;
FIG. 3 is a cross sectional view taken along line III--III of FIG.
1;
FIG. 4 is a longitudinal sectional view of an alternative
embodiment of the present invention;
FIG. 5 is a cross sectional view taken along line V--V of FIG. 4;
and
FIG. 6 is a diagrammatic illustration, partially in schematic, of
the pump control network of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings in detail and especially to FIGS. 1-3
and 6 thereof, a preferred embodiment of the pump 108 of the
present invention is shown. The pump 108 is preferably driven by a
hydraulic or pneumatic medium under pressure, the inlet and
discharge of this medium and of the fluid to be dosed or discharged
being, preferably, controlled by distribution slide valve or by a
distribution cock (not shown), the movement of which is preferably
controlled by a solenoid 102 (FIG. 6). The circuit (FIG. 6)
comprising the pump 108 and the solenoid 102 which controls the
pump distribution member located centrally inside the pump housing
is arranged in such a manner that the electric or energizing
circuit of the solenoid 102 is closed on receiving an impulse (for
instance one effected by the manual actuation of a push button 104
or by the momentary closing of a switch in the circuit by a cam)
and is maintained in the closed condition by an electromagnetic
switch in the circuit of the solenoid or by a spring loaded switch
109 controlled by the distribution member, the electromagnetic
switch or the spring loaded switch 109 being connected in parallel
with the push button 104 or the switch for imparting an electric
impulse to the solenoid. A switch which opens when a stop actuated
by the pumping member of the pump abuts against the switch member
of this latter switch is also preferably connected in the electric
or energizing circuit of the solenoid. Therefore, on excitation of
the solenoid it shifts the distribution member (slide valve or
cock) into its operative position, which distrubution member on
interruption of the excitation of the solenoid is moved back to its
starting position by spring action. Consequently, on receiving an
electric impulse the solenoid controls distrubuting member
distrubutingmember of the pump in such a manner, that the pumping
member of the pump executes one forward stroke and one return
stroke.
Now describing the embodiment shown in FIGS. 1-3 in greater detail.
The pump preferably includes a cylindrical housing portion 1, in
whch a pumping member constituted by a piston 2 is movable. Piston
2 is provided with a sealing member generally indicated by
reference numeral 3. One end of the cylindrical housing portion 1,
which forms a pumping chamber, is closed by a bottom wall 4 and the
other end by a partition wall 5.
The pumping chamber 6 is divided by piston 2 into two sections, one
section or chamber is defined by the partition wall 5 and piston 2,
and the other section or chamber is defined by the piston 2 and the
bottom wall 4. The volume of the chamber defined by piston 2 and
bottom wall 4, with piston 2 in the position shown in FIG. 1, is
essentially zero for all practical purposes. A conduit or
passageway 7 is located in the partition wall 5 and communicates
between a connecting nipple 8 and the pump chamber defined by
piston 2 and partition wall 5. Another conduit or passageway 9 is
located in bottom wall 4 and communicates between a connecting
nipple 10 and the pump chamber defined by piston 2 and bottom wall
4. A tube (not shown) for the fluid to be dosed can be connected to
each of the connecting nipples 8 and 10, the other ends of the
tubes being connected to the distributing member (slide valve or
cock, which is a conventional distribution means and is omitted for
purposes of clarity) controlled by the solenoid. When the solenoid
is not energized or excited the distribution member assumes a
position in which the conduit 9 is in open communication with a
discharge conduit (not shown) for the fluid to be dosed and in
which position the conduit 7 is in open communication with an inlet
conduit (not shown) for this fluid. When the solenoid is excited or
energized, the distribution member is shifted into a position in
which the conduit 9 is in open communication with the inlet
conduuit for the fluid to be dosed and in which position the
conduit 7 is in open communication with the discharge conduit
therefor.
A pumping member in the form of a diaphragm 14 of flexible
material, such as rubber, is preferably clamped along its periphery
between a flange 11 of the housing portion 1 and a flange 12 of a
second housing portion 13 of electrically insulating material, such
as plastic. The diaphragm 14 is preferably clamped tightly at its
center between a disc 15 carried by a central rod 17 of the pump
piston 2 and a cylindrical co-axial portion 18 of rod 17. Rod 17 of
piston 2 is preferably slidably sealed in a central bore of the
partition wall 5. The diaphragm 14 is kept clamped by the
cylindrical portion 18 by means of a cup-shaped spring bracket 19
of a compression spring 20 arranged between this bracket and an
inner shoulder 21 of housing portion 13.
The interior space of housing portion 13 is divided by the
diaphragm 14 into a chamber 22 limited by the partition wall 5 and
into a chamber 23 present at the other side of the diaphragm 14
which chamber 23 is in communication with the ambient atmosphere by
an opening 101 in the wall of housing portion 13.
Chamber 22 is preferably in open communication with a conduit or
passageway 24 located in the partition wall 5 and ending in a
connecting nipple 25 to which a tube (not shown) for the hydraulic
or pneumatic medium under pressure for driving the pump is
preferably connected.
Upon the excitation or energizing of the solenoid controlling the
distribution member, the tube connected to the nipple 25 is
preferably put in open communication with an inlet conduit for the
medium under pressure. Upon interruption of the excitation of the
solenoid, the tube connected to nipple 25 is preferably put in open
communication with a discharge conduit for the exhausted medium.
During this operation piston 2 carries out one forward stroke,
against the action of spring 20, under the influence of the medium
under pressure and, subsequently, a return stroke under the action
of spring 20.
During the stroke of the piston 2 in the direction of the partition
wall 5, which for purposes of explanation shall be termed the
forward stroke, the fluid present in the section of the chamber 6
between piston 2 and partition wall 5 is preferably discharged
through conduit 7 and the fluid to be dosed is sucked into the
section of the chamber 6 between piston 2 and bottom wall 4 through
conduit 9. During the return stroke of piston 2, the section of the
chamber 6 between piston 2 and bottom wall 4 is emptied through
conduit 9 and the fluid to be dosed is sucked into the section of
the chamber 6 between piston 2 and partition wall 5 through conduit
7. As previously mentioned, the relative functions of conduits 7
and 9 as, alternately, inlet and outlet passageways for intake of
the fluid to be dosed and, respectively, discharge of the fluid
from the appropriate section of the chamber 6 is controlled by the
positioning of the distribution member which is, in turn,
controlled by the solenoid.
The surface of the cylindrical portion 18 of rod 17 is provided
with two diametrically opposed helical grooves 26 and 27 having a
pitch at least equal to the maximum stroke length of piston 2. A
first co-axial sleeve 28 is rotatable around cylindrical portion 18
and is provided at its inner side with two cams 29 which are
diametrically opposed to each other, each being in engagement with
one of the helical grooves 26 and 27. Thus, when sleeve 28 is
rotated with respect to the cylindrical portion 18 it is displaced
in an axial direction in relation to that portion 18.
The first co-axial sleeve 28 fits slidably in an axial direction in
a second sleeve 30 which is also co-axial with the central rod 17
of the pumping member 2 but which second sleeve is preferably not
rotatable with respect to sleeve 28. The second sleeve 30 is
rotatably journalled in housing portion 13 and is preferably locked
against movement in the axial direction. The first co-axial sleeve
28 is preferably locked against rotation with respect to the second
co-axial sleeve 30 by external axial ridges 31 slidably engaging
corresponding axial grooves 32 in the inner wall of the second
co-axial sleeve 30. The end 33 of sleeve 30 protruding from housing
portion 13 preferably carries an adjusting knob 34 rigidly secured
to the sleeve 30. Therefore, the axial position of sleeve 28 with
respect to piston 2 and sleeve 30 can be adjusted as desired by
rotation of knob 34, and, thus, as will be explained in greater
detail hereinafter, the capacity or quantity of fluid dischargeable
by the pump during one working cycle can be predictably varied or
adjusted to any desired amount, merely by changing the forward
stroke of the piston 2. Sleeve 30 is provided with two flanges 35
and 36 between which extend ribs 37 (FIG. 2) opposing each other
diametrically. Each of these ribs has a bore in which a locking
member 39 constituted by a ball can move under the influence of a
compression spring 38. A cylindrical portion 40 of the housing
portion 13 is provided with internal axial grooves 41 (by way of
example twelve such grooves 41 are shown) into which the balls 39
snap successively on rotation of sleeve 30.
The cylindrical portion 40 is preferably co-axial with another
cylindrical portion 42 of the housing portion 13 of electrically
insulating material, and preferably extends into spring 20 for a
portion of its length. The annular wall portion 43 (FIG. 2) of the
housing portion 13 connecting the cylindrical portions 40 and 42
and constituting the shoulder 21 is preferably provided with two
ribs 44 arranged diametrically opposite to each other, each having
a radial bore which preferably contains a terminal 45 of the limit
switch contained in the electrical or energizing circuit of the
solenoid which controls the distribution member of the pump. Each
terminal 45 has a central bore in which an end contact 47
constituted by a ball can slide under the action of a compression
spring 46. In the closed position of the limit switch, the balls 47
are pushed against the periphery of a contact ring 48 of
electrically conductive material which constitutes a switching
member, which ring is carried by a bushing 49 of electrically
insulating material. Bushing 49 is preferably mounted slidably in
the axial direction on a bushing 50 which is also similarly
preferably mounted slidably in the axial direction between the
second co-axial sleeve 30 and the bushing 49 and is guided by
sleeve 30. At each of its ends bushing 50 is provided with a flange
51 and 52, respectively. A compression spring 53 preferably bears
on flange 52 of bushing 50 and on flange 35 of the second coaxial
sleeve 30 and preferably pushes bushing 50 into the position shown
in FIGS. 1 and 3. In this position of bushing 50, its flange 52
rests against bushing 49 carrying contact ring 48. The limit
switch, which is constituted by the parts 45, 47 and 48, is closed
when bushing 49 occupies the position shown in the drawing (FIG.
1). A ring 53 is preferably located in an annular groove in the
inner wall of the cylindrical housing portion 40 and constitutes a
stop for bushing 49 so that spring 53 in conjunction with bushing
50 can push the bushing 49 carrying the contact ring 48 into a
position in which the end contacts 47 rest against a cylindrical
portion of the periphery of the contact ring 48. This cylindrical
portion of the periphery of the contact ring 48 preferably has a
smaller diameter than the outer wall of bushing 49 which is guided
by the inner wall of the cylindrical housing portion 40, the
cylindrical portion of the contact ring 48 preferably merging by
means of a conical surface with the outer surface of bushing
49.
Preferably, between flange 51 of bushing 50 and bushing 49 a
compression spring 54 is mounted. The action of this spring 54 will
be explained in greater detail with reference to the operation of
the pump.
The cylindrical housing portion 40 is preferably provided with
axial external ribs 56, four being shown by way of example, each
rib preferably having a bore 57 having screwthread therein for a
fastening bolt for securing the pump to a support, for instance to
a fixed wall provided with an opening corresponding to the end 33
of sleeve 30.
OPERATION OF EMBODIMENT OF FIGS. 1-3
When the electric or energizing circuit of the solenoid which
controls the distributing member of the pump is closed, the
distribution member is moved by the solenoid into a position in
which conduit 24 is in open communication with the inlet conduit of
the distribution member for the medium under pressure, conduit 9 is
in open communication with the inlet conduit of the distribution
member for the fluid to be dosed, and conduit 7 is in open
communication with the discharge conduit of the distribution member
for this fluid. In this position of the distribution member,
diaphragm 14 is moved (to the left as shown in the example of FIG.
1) against the action of spring 20 by the medium under pressure
which fills chamber 22, so that pumping member or piston 2 carries
out a stroke in the direction of partion wall 5. During this
movement of the pumping member, the fluid to be dosed present in
chamber 6 between piston 2 and partition wall 5 is discharged in
proportion with the stroke length covered by the pumping member 2
and an equal quantity of the fluid to be dosed is sucked into the
section of the chamber 6 formed between pumping member 2 and bottom
wall 4.
The cylindrical portion 18 of rod 17 is provided with a switching
cam constituted by a flange 55, flange 51 of bushing 50 being in
the path of this switching cam 55. When switching cam 55 abuts
against flange 51 of bushing 50, this bushing moves in unison with
the pumping member 2, during which movement springs 53 and 54 are
compressed and flange 52 of bushing 50 no longer contacts the end
of bushing 49.
When the tension of spring 54 reaches such a value that the conical
surface of ring 48 urges the end contacts back in their bores or
when the windings of spring 54 rest against each other, bushing 49
slowly moves in an axial direction (to the left in the example of
FIG. 1) until the bevelled end of the cylindrical surface of ring
48 has reached balls 47. At this moment the resistance of bushing
49 and, thus, of ring 48, against movement in the axial direction
vanishes and bushing 49 together with the contact ring is moved by
the spring 54 with a snapping action into a position in which the
windings of spring 53 rest against each other and in which the end
contacts 47 rest against the surface of bushing 49 of electrically
insulating material. As a result of this the electric or energizing
circuit of the solenoid which controls the distribution member is
interrupted or opened so that the distribution member returns under
spring action to its starting position in which the conduit 24 is
again connected with the discharge conduit of the distribution
member for the medium under pressure. In the latter position of the
distribution members, conduit 9 is again in open communication with
the discharge conduit of the distribution member for the fluid to
be dosed, and conduit 7 is again in communication with the inlet
conduit of the distribution member for the fluid to be dosed.
Thereupon pumping member 2 under the action of spring 20, which was
loaded during the forward stroke, carries out a return stroke
during which the quantity of fluid to be dosed present in the
section of the chamber 6 between the pumping member 2 and bottom
wall 4 is discharged and an equal quantity of this fluid is sucked
into the section of the chamber 6 between partition wall 5 and
pumping member or piston 2.
When the limit switch 45-47-48 of the pump is closed under the
action of spring 53 during the return stroke of the pumping member,
the electric or energizing circuit of the solenoid remains
interrupted because the electromagnetic switch or the switch (109
in FIG. 6) operated by the solenoid distribution member controlling
the pump opens when this circuit is interrupted.
Since the stroke length of the pumping member 2 is determined by
the position of the switching cam 55 acting on flange 51 of bushing
50, the quantity of fluid to be dosed by the pump can be adjusted
by rotation of knob 34. Because the pitch of the helical grooves 26
and 27 substantially corresponds to the maximum stroke length of
the pumping member 2, and desired quantity of the fluid to be dosed
can be adjusted over the full range of the pump by rotating knob 34
over less or at the most over 360.degree.. If desired, a scale
division can be utilized in conjunction with the knob 34 on which
the adjusted quantity of fluid to be discharged by the pump can be
read directly by calibrating the degree of rotation to the stroke
length and, hence, to the quantity of fluid to be dosed.
As mentioned, spring 54 is compressed when the switching member 55
abuts against flange 51 of bushing 50. Owing to this, an axial
force is exerted on sleeve 28. Because the cams 29 of sleeve 28
engage the helical grooves 26, 27 of portion 18, sleeve 28 has the
inclination to rotate (counter clockwise in the example of FIGS. 2
and 3). Such rotation is prevented by the second co-axial sleeve 30
with respect to which sleeve 28 is locked against rotation as
mentioned. In turn, sleeve 30 is prevented from rotation by the
locking means 39 engaging the grooves 41. Rotation of the
cylindrical portion 18 in the clockwise direction (in the example
of FIGS. 2 and 3) is also prevented because diaphragm 14 is clamped
between the flanges 11 and 12.
For purposes of clarity, in FIGS. 1 and 2 the nuts of the inner
wall of the cylindrical housing portion 40 are shown in a different
position in FIG. 3 from that shown in FIGS. 1 and 2. Similarly, the
grooves 32 in the inner wall of the second co-axial sleeve 30 are
shown in a different position in FIGS. 2 and 3 from that shown in
FIG. 1 for purposes of clarity.
The distribution member may be connected with the connecting
nipples 8 and 25 also in such a manner, that in its position of
rest the conduit 8 is connected with the inlet conduit for the
medium under pressure and conduit 24 is connected with the
discharge conduit for the medium under pressure. Upon excitation or
energizing of the solenoid this situation is reversed. In such an
instance, spring 20 may be eliminated because the return movement
of the diaphragm 14 would be effected by the medium under pressure.
Since the fluid to be dosed in such an instance is sucked in and
discharged, respectively, only by conduit 9, the pump discharges
only approximately half the quantity of fluid at each forward and
return stroke of piston 2.
ALTERNATIVE EMBODIMENT
Referring now to FIGS. 4 and 5, an alternative embodiment of the
pump of the present invention is shown. The embodiment of the pump
shown in FIGS. 4 and 5 is arranged in such a manner, that it is
preferably driven directly by a solenoid, the limit switch of the
pump being connected in the energizing circuit for this solenoid in
the same manner as shown in FIG. 6. In this alternative embodiment,
the excitation of the solenoid is preferably started by a momentary
electric impulse, for example by means of a push button (see FIG.
6) with which an electromagnetic switch or a switch (similar to
switch 109 in FIG. 6) influenced by a spring and actuated by the
solenoid is connected in parallel in the electric or energizing
circuit of the solenoid.
The housing of the pump shown in FIGS. 4 and 5 preferably includes
two cylinders 58 and 59 of electrically insulating material, such
as plastic, in one piece, a bottom 60, and diaphragm 61 of rubber,
or another material having a sufficient flexibility, being clamped
along its periphery between bottom 60 and flange 62 of the
cylindrical housing portion 58. Bottom 60 is preferably provided
with a connecting nipple 63 for an inlet conduit for the fluid to
be dosed and with a connecting nipple 64 for a discharge conduit
for this fluid. Nipple 63 is provided with an inlet valve and
nipple 64 with an outlet valve for this fluid.
A disc 66 is preferably vulcanized into the center 65 of diaphragm
61. A central piston rod 67 protruding from the pump housing 58, 59
is preferably secured to disc 66, such as by welding. Rod 67
preferably carries a cylindrical portion 68 which is co-axial to
rod 67 and rigidly secured to it. The cylindrical portion 68 is
preferably provided with two helical grooves 69 and 70 which are
diametrically opposite to each other and into which engage two
diametrically opposed cams 71, 72, respectively, of the inner wall
of a first co-axial sleeve 73 rotatably mounted on cylindrical
portion 68.
A cup-shaped spring bracket 74 which accommodates the end of a
compression spring 75, the other end of which bears against a
shoulder 77 formed by the annular wall 76 (FIG. 5), is preferably
located between diaphragm 61 and the cylindrical portion 68.
The first co-axial sleeve 73 is preferably slidable in an axial
direction in a second sleeve 78 of electrically insulating material
and is co-axial with rod 67 and rotatably mounted in an extension
79 of the cylindrical housing portion 59 and extends within spring
75 into the cylindrical housing portion 58. Sleeve 73 is preferably
provided with a plurality of external axial ribs 80 slidably
engaging corresponding axial grooves 81 in the inner wall of sleeve
78, so that the sleeves 73 and 78 preferably cannot rotate with
respect to each other. Sleeve 78 further is preferably rotatably
mounted in a bore of a bolt 82 screwed into the cylindrical housing
portion 59, the bolt 82 being co-axial with rod 67, and by means of
which bolt the pump can be secured in an opening of a support. The
end of sleeve 78 protruding from bolt 82 constitutes an adjusting
knob 83 by means of which the position of sleeve 73 can be adjusted
in an axial direction and which also constitutes a bearing for rod
67.
The limit switch in the electric or energizing circuit of the
solenoid driving the pump is preferably constituted partially by
two terminals 85 secured in the bores of two diametrically opposed
ribs 84 of the annular wall 76. Each terminal 85 is provided with a
longitudinal bore for accommodating an end contact 87 constituted
by a ball loaded by a spring 86, which ball is slidably mounted in
the bore. When the pump is at rest, balls 87 are each pushed into a
round recess 88 by springs 86. A ring of such recesses 88 is
preferably arranged in a radial plane in a contact ring 89 of
electrically conductive material and carried by sleeve 78. Contact
ring 89 is rigidly secured to sleeve 78, each of the recesses 88
preferably being located at the bottom of an axial V-shaped groove
90 at the periphery of ring 89. Corresponding V-shaped grooves 92
are preferably located, in line with the grooves 90, in the outer
wall of the cylindrical portion 91 of sleeve 78 and guided by the
extension 79 of the housing.
A nut 93 locked by a locknut 94 is preferably screwed on to the end
of the piston rod 67 protruding from the bore of the securing bolt
82. Nut 93 is preferably provided with a radial bore 95 into which
is secured one end of a schematically shown spring 96, the other
end of which is connected to the armature of the solenoid (not
shown) driving the pump.
The end of the first co-axial sleeve facing away from diaphragm 61
is preferably provided with an end wall 97 constituting a switching
cam and having a central opening through which piston rod 67
extends. A compression spring 98 is preferably arranged around the
portion of rod 67 extending between the end wall 97 and the
adjusting knob 83.
OPERATION OF ALTERNATIVE EMBODIMENT (FIGS. 4-5)
When the solenoid, the armature of which is connected to spring 96,
it excited or energized, such as by a transitory actuation of a
push button connected to its electric or energizing circuit, this
circuit being kept closed by an electromagnetic switch or by a
switch actuated by the solenoid driving the pump which switches are
connected in parallel with the switch for initiating the energizing
of the solenoid, the pumping member (diaphragm 61 in this
embodiment) carries out a forward stroke (away from bottom 60 in
the example of FIGS. 4 and 5). During this stroke of the pumping
member, fluid to be dosed is sucked into the pump chamber and
spring 75 is tensioned. When the disphragm 61 has covered the
forward stroke, the length of which is determined by the position
of sleeve 68 with respect to sleeve 78, spring 98 present between
the switching cam 97 and the adjusting knob 83 is compressed.
When spring 98 has reached a tension which corresponds to the force
required to move sleeve 78 in an axial direction against the action
of springs 86, the balls 87 leave the round recesses 88 and sleeve
78 in brought with a snapping action into a position in which
contact ring 89 rests against a shoulder 99 arranged in the housing
portion 59. In this position of sleeve 78, the balls 87
constituting the end contacts of the switch rest against the
surface of portion 91 of sleeve 78. Because sleeve 78 consists of
electrically insulating material, the electric or energizing
circuit of the solenoid is interrupted by this snapping movement of
sleeve 78. Diaphragm 61 then carries out its return stroke under
the influence or drive of compression spring 75 which had been
loaded or tensioned during the forward stroke of the diaphragm 61.
During this return stroke of the diaphragm 61, the fluid sucked
into the pumping chamber is discharged through the outlet valve.
Because the stroke length of the diaphragm 61 is determined by the
axial position of sleeve 68 with respect to sleeve 78, it is clear
that the quantity of fluid discharged by the pump can be adjusted
by rotation of knob 83. Also, with this embodiment of the pump,
each desired quantity of fluid to be discharged by the pump can be
adjusted over its full range by rotation of knob 83 over at the
most 360.degree., because the pitch of the helical grooves 69 and
70 substantially corresponds with the maximum stroke length of the
pumping member 61. Thus, as mentioned with respect to the
embodiment shown in FIGS. 1-3, the degree of rotation of the knob
may readily be calibrated to the stroke length and, hence, to the
quantity of fluid discharged by the pump.
Because each of the spring loaded end contacts 87 engages the
subsequent axial groove 90 of sleeve 78 each time knob 83 is
rotated, and because every groove 92 of the portion 91 of sleeve 78
is in line with the corresponding groove 90, sleeve 78 is locked
against rotation during the opening procedure of limit switch
85-86-87-89, so that the position of this sleeve as adjusted is
maintained.
When diaphragm 61 approaches the end of its return stroke, nut 94
abuts against the adjusting knob 83 and moves this back to the
starting position illustrated in FIG. 4. Preferably, a ring 100
arranged in an annular groove in the inner wall of the extension 79
of the housing portion 59 determines the end position of sleeve 78
during this movement back to its starting position.
It will be clear that with the embodiment of the pump shown in
FIGS. 4 and 5, the end contacts 87 take over the task of the
locking means 39 of the embodiment shown in FIGS. 1-3. If, in this
latter embodiment, the bushings 49 and 50 as well as spring 53 are
eliminated and contact ring 49 is carried directly by sleeve 30,
and if these latter parts are provided with grooves corresponding
with the grooves 90 and 92 of the contact ring 89 and of the sleeve
78, respectively, and if the contact ring 48 has the same shape as
contact ring 89, then the locking means 39 can also be eliminated.
It has to be realized however, that with such a modification, the
adjusting knob 34 moves over a short distance in the axial
direction when the limit switch 45-46-47-48, is opened.
Since the pump of the present invention can be connected in such a
manner in the energizing circuit of a solenoid that on receiving an
electric impulse by the solenoid the pump carries out only a single
forward stroke and a return stroke and discharges during this
operation a previously adjusted quantity of fluid, it is very
suited for devices in which the switch for putting the pump into
operation is actuated by a manually actuated push button or by a
cam of a programming disc of the device.
As used throughout the specification and claims, the term "fluid"
is meant to include gasses as well as liquids, including viscous
mediums.
It is to be understood that the above described embodiments of the
invention are merely illustrative of the principles thereof and
that numerous modifications and embodiments of the invention may be
derived within the spirit and scope thereof.
* * * * *