Note: Descriptions are shown in the official language in which they were submitted.
ELECTRICALLY CONTROLLED VAbVE APPARATUS
The present invention relates to an electrically controlled
valve flpparatus provided with an inlet conduit for the
pressurized fluid, with an outlet cond~lit for a tank or
equivalent in order to drain the Fluid from the valve, and
with an outlet conduit for an actuator proper, such as a
cylinder.
s
In the course of the development of hydraulic eievators,
certain important requirements as to their operation have
~been set forth, among them: a driving speed independent of
the load, a stepless acceleration independent of the load,
and a slow-down in both directions as well as an
approaching speed likewise independent of the load. In
addition to this~ some manufacturers have tried to reduce
the amount of required electronics, for instance on grounds
that the consumption of electricity should be cut downO
for example, the SE publication of application 367 172
introduces a solution which aims at employing two magnetic
valves. The said aim is achieved, but as regards
hydraulics, the result is an extremely complex valve
assembly composed of magnetic valves of the simpLe on-off
type, which either close the respective flow path, or the
flow path remains completelyopen.
In a like manner, the valve construction introduced in the
DE publication of application 1 268 aOl fulfils the above
mentioned requirements set forth for modern technique, but
dpes 90 by means of hydraulic arrsngements even more
complicated than in the said SE publication. Among other
things7 the appsratus comprises two magnetic valves of the
on-off type, two operating spindles, a precision spindle as
well as two throttle valves and a current distributor
valve. The latteris needed for driving independent of the
load.
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The third exa~ple is tha US patent publication 4 41a 794.
The valve introduced in this publication comprises three
operating spindles9 one of which i9 employed steplessly by
means of an electric motor, a screw sleeve and a screw bar,
as well as an on-off type magnetic valve and one
pressure-controllecl directional valve. Consequently, this
valve arrangement is fairly complex, too, mainly owing to
the large number of components of different types.
As a conclusion of the publications referred to as
representants of the prior art, it is observed that the
common aim is to avoid electric components, but this leads
to complicated hydraulic arrangemets and a disorderly
confusion in the resulting technique~ None of the described
apparatuses, however, is realized wlthout electromagnetic
valves, and apart from one, they are of the on-off type.
Furthermore, the reducing of electronic elements on the
basis that the consumption of electricity should be cut
down seems poorly justified, because with complicated f
valves the current losses in the hydraulics are probably
greater than the amount of electricity required by the
electronics.
The purpose of the present invention is to eli~inate the
above mentioned drawbacks, among others, and to realize a
valve apparatus which is simple in structure and reliable
in operation. This is achieved by means of the
i
characteristic novel features of the invention, presented
in the appended patent claims.
In the present invention, the old way of thinking has been
totally abandoned, and the general idea is to utilize the
possibilities offered by modern electronics - which, as
regards energy consumption, are absolutely more economical
than complicated hydraulios with their current losses. At
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the same -time, the whole way of thinking about valves
has been revised. The main idea is to simplify the
hydraulics and to achieve orderly clarity in the
-technical realization of the apparatus itself.
Accordingly, only the compulsory operations are left
to be carried out by hydraulics, and all that can be
done by electric, electronic or similar components,
is also done by them.
In accordance with the invention, there is provided
an electrically controlled valve apparatus,
comprising: a housing defining a fluid chamber, said
housing including an inlet pressurized fluid conduit
and an outlet pressurized fluid conduit; a tank
connected -to -the outlet conduit for receivlncl fluid
discharged Ero~ the outlet conduit; Eirs-t and second
openings in said fluid chamber, each of said openings
being fi-tted with respective Eirst and second
operating spindles; an actuator such as a cylinder,
second outlet conduit providing fluid connection
between said actuator and said chamber, said first
and second openings allowing pressurized fluid to
flow from said chamber through the first and second
outlet conduits to said actuator and to said tank and
from said actuator to said tank in accordance with
the position of said first and second operating
spindles with respect to the first and second
openings, said first and second openings and
respective first and second operating spindles
cooperating to form first and second back chambers;
first back chamber conduit providing fluid connection
between said second outlet conduit and said second
back chamber; second back chamber conduit in fluid
connection with said second back chamber and also in
fluid connection with said first back chamber and
- 3a -
said first outlet conduit; a -first -throttle valve for
constricting fluid flow from said second back chamber
to said second back chamber conduit; a second
throttle valve -for constricting fluid flow from said
second back chamber conduit -to said first back
chamber; and throttle controlling actuator for
controlling the operation of said first and second
throttle valves; a lift cage drivingly connected to
said actuator for movement in an upward and downward
direction; at least one sensor for measuring a
motional aspect of said lift cage; control means
connected to said sensor for receiving sensed
informa-tion and connected to said throttle valve
actuators, for adjusting said throttle valves on the
basis of inEormation received from said sensors, so
as to position the operati.ng spindles for hydraulic
flow through said openings such that the lift cage is
moved in a predetermined rnanner.
In another embodiment of the invention, the
controlling of the operating spindles of the valve
apparatus is carried out by means of one single
combined throttle valve instead of the two separate
-throttle valves of the first embodiment
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In the vfllve apparatus according to the first embodiment,
the sensors are used for measuring the volume flow of the
hydraulic fluid, i.e. the length of the axial movement of
the operating spindle, which indirectly means the velocity
of the li~t oage or equivalerlt, wh~reas in the second
embodiment the velocity of the lift cage i9 measured
directly by means of a suitable impulse sensor. In both
embodiments, the information received from the sensor is
processed in the control unit and utilized for controlling
the throttle valve or valves, by aid of which throttle
valves, and through two operating valves, there is adjusted
the volume of the hydraulic flow from the pump into the
cylinder of the lift cage or of the hoist device and into
the tank, as well aR from the cylinder into the tank.
Several advantages are achieved by employing the valve
spparatus of the present invention, particularly if the
invention is applied For regulating the operstion of
hydraulic elevators. The lift cage can be stopped exactly
at the correct floor landing. The creaping distance and
velocity follow the given measures accurately. Changes in
the load do not affect the said measures. ~ariations in the
temperature of the hydraulic fluid, and the resulting
varia-tions in the volume, do not cause erroneous functions
2S and/or creeping; ~the position of the lift cage is
automatically corrected. Inside the lift cage there can be
arranged an alarm button whereby the cage can be made to
descend to a desired lower floor. It is pointed out that a
similar arrangement is not commercially available for
hydraulic elevators at the moment, but in slarm cases the
lift cage must be descended from the engine room. Moreover,
the valve apparatus proper is simple in structure; the
number of separate hydraulic elements has fallen to about
half of what is normally used. With respect to the size of
the valve apparatus, the treated volume o~ hydraulic fluid
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is at least doubled in comparison with ordinary valve
apparatuses of the correspondi.ng size.
In the following, some of the preferred embodiments of the
present invantion are explained in more detail with
reference to the appended drswings, where
Figure 1 shows in partial cross-section a valve apparatus
of the invention, applied to a hydraulic
elevator; and0 Figure 2 is a diagram of the lift cage velocity achieved
by employing the said valve apparatus;
Figure 3A is an illustration of another vslve apparatus of
the invention, likewise applied to an elevator
and5 figure 3B illustrates the wobbler attached to the stepping
motor, seen from the top; and
Figure 4 is a block diagram of a control unit which is
suited for controlling the valve apparatus of the
invention.
According to Figure 1, the valve apparatus comprises the
valve housing 1, which is provided with an inlet conduit or
opening 2, seen from the entering direction o~ the
hydraulic fluid, through which opening the fluid
pressurized by the pump P enters the valve apparatus from
the tank T. The inlet conduit 2 is provided with a
countervalve 3 and strings 4. After passing this, the
pressure fluid enters the first chamber 5. By aid of the
said fluid, the two operating spindles 6 and 7,
advantageously charged by the ~trings 8 and 9, are pressed
in the chamber 5. When the spindle 6 is urged against the
string power, a return conduit 12 is opened for the fluid
through the first opening 10 directly back into the tank
T. In addition to this, the operating spindle 6 comprises a
shaft 13 or equivalent which protrudes from the valve
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housino 1. Similarly, a shaft 14 or br~cket protrudes from
the valve housing 1, the said sheft being provided with the
sensors 15 arld 16 attached thereto, ~hich sensors react to
the movement of the sheft 13 and thus to the movement of
th~ ope~ating spindle 6 by sending respective impulses to
the control unit 17.
From the chamber 24 located behind the first operating
spindle 6, a conduit 25 leads to the throttle valve 26,
which is electrically controlled. The spindle 27 of the
throttle valve 26 is advantageously conical in shape. By
employing this valve, it is possible to regulate the flow
taking plflce through the opening 2~, From the chamber 24
via the conduit 25 into the conduit 29 which leads into the
fluid tank T. Moreover~ the chamber 24 i9 connected to the
inlet conduit 2 by means of a conduit 3û.
- The second operating spindle 7 functions in a similar
fashion as the first operating spindle 6. When it is urged
2û by the pressure against the string power of the string 9,
the hydraulic fluid has access through the second opening
18, into the outlet conduit 19, which leads onto the
cylinder S serving as the actuator of the elevator HS or
the like. The spindle 7 also comprises a sh~ft 2û or
equivalent, and a shaft 21 or bracket protruding ~rom the
valve housing, the said shaft 21 being provided with
sensors 22 and 23 attached thereto, which sensors send
impulses to the control unit 17 in accordance with the
movements of the spindle 7. Behind the spindle 7~ there is
located the chamber 31, whereto the conduit 32 leads from
the actuator connectionS i.e. from the conduit 19. From the
chamber 31, there alqo leads the conduit 33 via the
countervalve 34 to the second throttle valve 35, which is
likewise electrically controlledO By aid of the spindl0 36
pertaining to this valve 35, which spindle is edvantage-
eD6l~
ously provided with a conical collar 36a, it is possible to
olose the conduit or the opening 37 on the opposite side of
the countervalve 34. The spindle 36 has a pin-like head
36b, which is used for opening the countervalve 34 in the
cQnduit 37 b~fore the collar 36a of the spindle 36 closes
the flow path, i.e. the conduit 37. The conduit 38 leads
from the throttle valve 35 directly into the fluid tank r.
In the preferr0d embodiment of Figure 1 ( as well as Figrure
3)J the valve spparatus of the invention is connected to a
hydraulic elevator, the actuator whereof is the cylinder
~S. In this case the lift cage HS is in an exemplary fashion
arranged to move between the landing Kl of the first floor
and the landin~ K2 of the second floor. On both floors
there are arranged oall buttons KPl and KP2, snd the lift
caga i8 provlded with respective floor buttons Pl and P2 aR
well as with an alarm button HP. All buttons are connected
to the control unit 17. When the lift cage HS moves from
one floor to another, its approach towards the floor
landing i9 observed in conventional fashion by means of the
approach signals Ll and L2, and its arrival at the floor
landings Kl, K2 is observed by means of the floor signals
KL1 and KL2 and the sensor AH attached to the lift cage.
The use of signsls belongs to the domain of the prior art,
and it is not discussed further in this connection.
Naturally the number of floors and landings where the lift
cage HS stops can be larger than above.
The operation of the valve apparatus of the invention is
below explained with reference to the velocity diagram of
the elevator, iLlu~trated in Figure 2. The initial position
confirms to the situation illustrated in figure 1 and is
marked by point A in figure 2. The elevator HS is on the
first floor Kl, snd the floor button P2 or the call button
KP2 of the elevator has been pressed, i.e. it is desired
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KP2 of the elevator has been pressed, i.e. it is desired
that the elevator rises to the second floor. The messs~e is
registered in the control unit 17. Through the control unit
17, the pump P is started, ~dvantageously fir~t with a
small efficiency only. After the pump P has been started,
the counterv~lve 3 is opened due to the hydraulic pressure,
and the hydraulic pressure formed in the chamber 5 shifts
the first operating spindle 6 to the left and thus allows
the fluid flow to enter, via the conduit 12, back into the
lû tank T. The fluid located in the chamber 24 behind the
spindle 6 is pressed into the conduit 25, pushes the
.spindle 27 open and flows along the conduit 29 baclc into
the tank T. When the pump P has been switched to work with
full power, the control unit 17 has s.i.multaneously switched
a control voltage to the electrioally controlled throttle
valve 26 and started to observe the sensors 22 and 23. All
this time the hydraulic fluid has flown along the condui-t
30 from the inlet conduit 2 into the chamber 24 and further
aiong the conduits 25 and 29 back into the tank T.
When the ccntrol voltage onto the throttle valve 26 is
evenly increased under the control of the control unit 17,
the said throttle valve 26 pushes the spindle 27 outwards
and constricts the opening 28 thus preventing the fluid
from flowing through, so that the pressure within the
chamber 24 is increased. The operation spindle 6 is
shifted, due to the effect of the pressure and the string
8, to the right towards the seat, thus constricting the
opening lû and dacreasing the return flow through -the
conduit 12 into the tank T. Now the pressure in the chamber
5 increases and starts to affect the other spindle 7. On
the other hand, the pressure of the actuator such as the
cylinder 5 which is employed for hoisting the lift cage H5,
affects in the conduit 19 and also, via the conduit 32, in
the chamber 31 located behind the spindle 7. When in due
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course the pressure effect of the chsmber 5 surpasses that
of the chamber 31 and the spring load of the spring 9, -the
spindle 7 lifts up from the seat and the pressure fluid
starts to flow through the opening 18 via the conduit 19
into the cylinder S. The elevator 1-15 starts to ri~e evenly
with accelerating speed, A-B in figure 2, becsuse the
voltage onto the throttle valve 26 is evenly increased.
When the operating spindle 7 is lifted so far above its
seat that the shaft 20 has risen to the same level with the
sensor 22, this sends an impulse to the control unit 17
which interrupts the increasing of the voltage onto the
valve 26. Now we are at the point B of Figure 2. Conse-
quently it c~n be maintained that the operating spindle 7
measures fluid flow and the operating spindle 6 regulates
the flow during the hoist stage of the lift cage H5.
The lift cage HS is now driven with constant speed to the
desired floor, in this case the second floor - the interval
B-C in Figure 2. The voltage of the throttle valve 26
remains constant, in which case the operating spindles 6
and 7 also stay in position. When the aim is approached and
the height C achieved, an impulse i9 sent to the control
unit 17 by mesns of the floor approach signal L2 or
equivalent and the sensor AH, whereafter the control unit
starts evenly reducing the control voltage onto the
throttle valve 26. Now the operating spindle 6 moves slowly
to the left, away from the seat, while the spindle 27 of
the throttle valve 26 keeps opening the opening 2B and the
conduit 25, which causes a constantly growing amount of the
~0 hydraulic flow from the pump P to be conducted diretly into
the tank T via the chamber 5, the opening 10 and the
conduit 12. As a consequense, the pressure in the chamber 5
is reduced, and the operating epindle 7 i3 shifted
downwards towards the seat - i.e. the opening 18 is
constricted. Hydrsulic fluid doe~ not flow as quickly as
~ 3
before from the chamber 5 via the opening 10 and the
conduit 19 into the cylinder S, whioh means that the speed
of the lift cage HS is slowed down. The same development
continues until we reach point D in Figure 2; now ths head
of the ~haft 20 has in reality shifted, along with the
spindle 7, to the same level with the sen-,or 23. The sensor
23 sends sn impulse to the oontrol unit 17, which stops
reducing the control voltsge onto the valve 26. This makes
the fluid volume flow onto the cylinder 5 constant, whereby
the rising speed of the lift cage HS is also made
constant. Thus the cage continues to rise, but at a
creeping speed remarkably slower than before - the interval
D-E, Figure 2. When the lift cage has resched the height E,
which information is received from the floor signal K~2 and
the sensor AH~ the pump P is stopped and the power is cut
off from the throttle valve 26 a~ter a short time la9
arranged in the control unit 17. The time lag prevents the
lift cage HS from stopping abruptly.
When it is desired that the lift starts off downwards from
for instance the second floor K2 to the first floor Kl,
i.e. from the point F in Figure 2 downwards, it is
necessary to press either the floor button Pl in the
elevator or the call button KPl located on the First
floor. Then the other electrically controlled throttle
valve 35 and the sensors 15 and 16 are activated through
the control unit 17. With the permission of the eontrol
unit 17, a maximal control voltage is fed on the throttle
valve 359 so that the spindle 36 of the valve 35 strikes
outwards and opens the countervslve 34 by means of its
pin like head 36b, simultaneuosly closing the conduit 37
itsslf by meens oF its conical collar 36a. Thereafter,
under the oontrol of the control unit 17~ the reduction of
the control voltage in the throttle valve 35 is started in
~n even fashion9 in which ca~e the spindle 36 starts to
~ , .
move inwards and the conical collar 36a starts to open the
conduit 37~ Now the pressure fluid i9 dlscharged from the
chamber 31 via the conduits 33 and 38 into the tanl< T.
Because the cross-sectional area of the conduit 32 is
smaller than that o~ the conduit 33, the pressure in the
chamber 31 i5 reduced and tha second operating spindle 7 is
free to rise from its seat, thus allowing the fluid to flow
from the cylinder S via the conduit 19 and the opening lB
into the chamber 5~ From this chamber, the fluid is
lû discharged into the tank T by pushing the first spindle 6
against its spring 3 to the left, so that the opening 10
and the conduit 12 are opened. When the head of the shaft
13 of the spindle 6 has reached the sensor 15, the speed of
the lift cage HS has reached the desired point - i.e. the
interv~l F-G of the Fi9ure 2. Now the control unit 17 stops
the reduction of the control voltage of the throttle valve
35, and the elevator velocity remains at its defined
maximum for driving the interval between floor~ - G-H in
Figure 2.
When the lift cage HS approaches a floor it is bound to
stop, an impulse i~ sent for the c~ntrol unit 17 by meanR
of the floor approach signal Ll and the sensor AH. This
takes place at the point H of Figure 2. The control unit 17
starts increasing the control voltage evenly on the
throttle valve 35, so that the spindle 36 starts to move
~nd to con~trict the flow within the conduit 37. This makes
the pressure rise in the chamber 31, the operating spindle
7 to move downwards towards the seat and the opening 18 to
be constricted, 8S well as the operating spindle 6 to shift
to the right, away from the seat1 and the opening 10 to be
eniarged, in which case the speed of the lift cage HS is
slowed down, according to Figure 23 during the interval
H~I. When the speed has slowed down sufficiently, i.e. the
point I has been reached, the head of the shaft 13 has also
6 51
12
settled beside the sensor 16. Now the sensor 16 sends an
impulse to the control unit 17, which stops the increasing
of the control pressure on the throttle valve 35. The lift
cage moves at an even creeping speed during the interval
I-K in figure 2~
When the floor landing is reached, an impulse is sent to
the control unit 17 by means of the floor signal KLl and
the sensor AH. Now the lift cage HS is located at the point
K in Figure 2. The control unit 17 nullifies or switches
off the voltage from the throttle valve 35, so that the
spindl0 36 moves up from the conduit 37, and the
countervalve 34 obstructs the flow via the conduits 33 and
3a. Now the hydraulic pressure in the chamber 31 rises and
lS urges the second operating spindle 7 down against the seat,
thus closing the opening 18 and the flow path From the
cylinder S into the tank T. As a ronsequence, the lift cage
HS is stopped. According, at the return stage the
operating spindle 6 is employed for measuring the flow and
the operating spindle 7 takes care of the regulation of the
flow.
As is obvious from the above description, the valve
apparatus of the inventlon is in principle formed of two
electro-hydraulic circuits, which comprise the first,
electrically controlled throttle valve 26, the conduits 25
and 29, as well as the sensors 22 and 23, and the second
electrically controlled throttle valve 35, the conduits 33
snd 3~ and the sensors 15 and 16. Furthermore, the first
operating spindle 6 and the second operating spindle 7 are
employed in different tasks, depending on the motional
direction of the elevator. Furthermore it is observed that
when the pump P i8 not in operation, the countervalve 34 is
used for stopping the lift cage at a determined height. As
is apparent from Figure 1, in the rest position the
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spindle 36 of the throttle valve 35 is pulled in and the
spindle 27 of the throttle valve 26 i8 pu~hed out.
As for the technical realization of the sensors 15~ 16, 22
and 23, they can be for example mugnetic or photoelectric
sensors, or other corresponding sensors of a conventional,
tried and ~cknowledged type. Similariy the heads of the
shafts 13 and 20 or the meMbers attached to the shaFts can
form an actively functioning pair together with a sensor,
or they can for instance only obstruct a ray of llght which
passes from the light emitting diode (LED) of the sensor
into the phototransistor or equivalent light detector.
Furthermore, it i~ possible to consider a solution where
the motion detectors are located in the valve housing 1
proper and react for example to an Fe-structure placed on
the surFace o~ the spindle 6, 7. This would make the valve
construction remarkably more simple in outlook, and at the
same time less vu-lnerable. On the other hand, when the
sensors are located on protruding shafts or corresponding
members, the limiting values of the lift cage motional
velocity are easily changed by shifting the sensors.
.
In the above description we have deliberately abstained
~rom going into detail while explaining the technical
realization of the electric actuators of the electrically
controlled throttle valves ~5 ancl 26, because they can be
realized in several different ways. It is possible that the
required adjustable, linear motion is created by means of a
rotsting electric motor, a screw sleeve and a sorew shaft~
or by means of a linear motor and Q spring, or in some
other fashion already known in the prior art.
:
Figure 3 A introduces another v~lve apparatus of the
invention. In connection to this valve apparatus, the same
reference numbers apply in the respective parts as in the
,. A
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embodiment of Figure 1. The valve apparatus comprises the
valve housing 1 provided with an inlet conduit 2 seen in
the entering dirPction of the fluid; through this inlet
conduit 2 the fluld pumped from the tank T by the pump P
enters the valve app~ratus~ The inlet conduit 2 is provided
with the count~rvalve 3 and string 4~ After passing thist
the hydraulic fluid is conducted into th~ chamber 5 where
its pressure i9 urged towards two operating spindles, the
first spindle 6 and the second spindle 7, both being-
provided with strings 8 and 9 on their opposite sides.When the first opersting spindle 6 i5 urged under pressure
against the string power, outwards from the seat, the first
opening lû is opened and simultaneuously there i9 opened
the direct return conduit 12 for the fluid back into the
tank T. Respectively, when the operating spindle 7 is
shifted from the seat against the spring pawer, the
hydraulic fluid has access, through ths opening 11, into
the conduit 19, which leads onto the cylinder S of the lift
cage HS.
2û
The second operating spindle 7 is formed of two matched
spindle elements 7a and 7b. Between these, the first
spindle element 7a covers the large openig 11 of the seat,
and the second 7b covers the small opening 39, which is
srranged in the middle of the first spindle. Behind the
operating spindle 7 there is located the chamber 31,
whereinto the conduit 32 leads from the actuator
connection, i.e. from the conduit 19. Also From the chamber
31, the conduit 40 leads out via tahe countervalve 41 onto
the throttle velve 42.
The countervalve 41 and the throttle valve 42 are placed in
the ssme valve duct 44, advantageously within a uniform
housing 43. The middle part 44b of the valve duct 44 is
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smaller in cross-section than either of its end parts 44a
and 44c. In the second closed end part 44c of the
valve duct 44 there i9 installed the countervalve 41, the
string 41a and a closure member such 8S the ball 41b. The
bRll 41b rests, undsr the pressure of the string 41a,
against the middle part 44b of the valve duct 44, so that
it closes the valve duct 44. The conduit 45 leads from the
other side of the countervalve 41, i.e. from the side
opposite to the conduit 40, directly into the tank T or
slternstively into the chamber 5 (the dotted line in Figure
3). The ball 41b of the countervalve 41 both prevents and
regulates the flow taking place from the conduit 40 via the
valve duct 44 into the conduit 45 and the tank T. The
spindle 46 of the throttle valve 42 is ~ bar-like member,
the First end 47 whereoP is pin-like. After this end l~7
comes the extension 4~ th~ conicel oollar 49~ the middle
psrt S0 and the other end Sl. The extension 48` is fitted
within the middle part 44b of the valve duct 44 so that it
prevents all flowing between the conduits 45 and 52. The
conical collar 49 of the spindle 46, and the midd~e part
44b of the valve duct, serve as the throttle valve 42
proper between the conduits 52 and 53. The conduit 53 leads
into the fluid tank T.
From the back space 24 of the second operating spindle 6,
the conduit 52 leads onto the throttle valve 42, and by
employing the collar 49 of the spindle 46 of the said valve
42 it is possible to regulate the flow from the space 24
via the conduit 52 into the conduit 53 and further into the
fluid tank T. Moreover, the space 24 is coupled to the pump
connection~ i.e. to the inlet conduit 2, by means of the
conduit 54.
16
In this embodiment of the valve apparatus, the shifting
device of the ~pindle 46 of the throttle valve 42 is the
stepping motor 55 with the wobbler 56 attached to it~ axis,
or an equivalent control member. The outlet conduit 19 of
the valve apparatus is connected to the employed actuator
proper ~uch as the hydraulic cylinder S, whereby the lift
cage HS, the hoist platform or the like can be lifted from
a landing or floor to another and descended in the like
m~nner.
lû
The velocity and position of the lift cage HS is observed
by means of the impul~e sensor 58. At the top and the
bottom of the lift well there flre arranged runner wheels
59, 60 or equivalent members, over which the wire cable 61
is arrsnged to slide. The wire cable 61 is attached to the
lift coge HS. The wire cable 61 runs through the impulse
sensor 5a. The impulse sen~or 58 comprises the round disc
58a, which i8 rotated by the wire cable 61 moving along
with the lift cage. The rotating of the disc i9 ~easured
for instance electrooptically, and the information is fed
into the control unit 57. The lift cage and the ssparate
floors are provided with similar floor and approach sign~ls
8S in the embodiment of Figure 1.
The operation of this valve apparatus according to the
present invention is also explained with reference to the
velocity illustration of Figu~e 2. In the initial position
we find ourselves in the situation illustrated in Figure 3
and at the point A of Figure 2. After starting the pump P,
the countervalve 3 is opened, 80 that the fluid prrssure
direoted to the chamber S shiFt9 the operating spindle 6
and allows the fluid to flow via the conduit 12 back into
the tank T. The fluid contained in the chamber 24 is
pressed into the conduit 52, whereQfter it pushes the 35
spindle 46 into open position (direction A) and is drained,
via the conduit 53, back into the tank T.
:
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17
The stepping motor 55 snd the wobbler 56 connected thereto
are first in home position. The short axis a of the wobbler
is now against the spindle 46 (Figure 3B). This home
position i9 detected for instance by aid of microswitch 62
placed on the opposite side of the wobbler. In this case
there can be even an interval between the spindle 46 and
the wobbler 56. The spindle 46 is pressed against the edge
of the wobbler when the pressure in the charnber 5 is
increased. The stepping of the motor 55 is begun under the
control of the control unit 57, and the wobbler 56 starts
to turn and to push the spindle into the direction B. Now
the conical collar 49 starts closing the opening between
the conduits 52 and 53. Within the chamber 24, the
hydraulic pressure in increasing and pushin9 the spindle 6
towards the seat and the chamber S. It closes the opening
and the conduit 12 into the tank T. Pressure in the
chamber 5 increases. When the pressure has increased
sufficiently, the operating spindle 7 (whole of the spindle
7a) i8 opened, and the fluid has access into the cylinder S
20 Vid the conduit 19. It is simultaneuously observed? by aid
of the control unit 57, whether the lif-t cage has taken
off. When the first motion impulse of the lift c~ge HS is
received f~om the impulse sensor 58. The acceleration of
the lift cage is started. If the first motion impulses come
in succession in a series quicker than should be allowed,
the stepping motor 55 is stepped backwards, so that the
spindle 46 moves into the direction A, i.e. the flow from
the conduit 52 into the conduit 53 is increased, and the
pressure within the chamber 24 is reduced, and the conduit
12 is slightly opened. This results in a soft and
controlled takeoff and initial acceleration of the lift
cage during the interval A-B of Figure 2. As soon as the
desirsd velocity of the lift cage is achieved, which is
observed by meana of the impulse sen~or 58, constant speed
is switched on - i.e. the control unit 57 stops the
i3i~9~
18
stepping motor 55, the wobbler 56 and the spindle guided
thereby are stopped in a given position; the interval
between the conduits 52 and 53 remains either totally
closed by aid of the conical collar 49, or partly open, in
which c~se part of the fluid can flow from the ch~mber 5
via the conduit 12 into the tank T.
When the desired interval, for instance between two floors,
is driven, the approach signal L2 sends a message in order
to start the slow-down - point C in Figure 2. Now the
spindle 46 is shifted into the direction A by employing the
stepping motor 55 and the wobbler 56 (or the hydraulic
pressure), so that the opening between the collar 49 and
the ventilation duct 44b is increased between the conduits
52 and 53, and simultaneously the fluid Plow from the
chamber 24 into the tank T is increased and the operating
spindle 7 closes part of the openin9 11 between the chamber
5 and the outlet conduit 19. This procedure is continued,
until the speed of the lift cage reaches n certain limit,
i.e. the point D in Figure 2, wherefrom the lift`cage is
-driven forward at the constant creeping speed, until a
message is received from the floor signal KL2.
By employing the impulse sensor 58, the floor information
is received with the acGuracy of +l mm. The floor
information is obstained for example from the lift well,
from the edge of the 100 mm wide floor signal KLl, KL2 in
the motional direction of the lift cage. The lift cage is
stopped by ~id of the control unit 57 at 50 mm from the
edge of the said signal, whereafter the pump P is stopped.
The timing of the downward drive corresponds to the
beginning of the upward drive described above; the pump P
is not started, however. The stepping motor 55 and the
wobbler 56 are sgain in home position (figure 3 B). In the
3~
19
beginning of the downwsrd driv~, the spindle 46 is pu~hed
sufficiently in the direction B by aid of the stepping
motor 55 and the wobbler 56, so thst the countervalve ~1 is
opened by means of the pin 47; the hydraulic fluid from the
back chamber 31 of the second operating spind:Le 7 starts to
flow into the tank T via the conduit 40, the countervslve
41 and the conduit 45. Thus n difference in pressure is
created between the chamber 31 and the outlet conduit 19 or
the cylinder S, and this diFference starts to lift the
inner spindle 7O o~ the second operating ~pindle 7 (the
hydraulic pressure can enter the aperture between the inner
spindle 7b and the outer spindle 7a, as is apparent from
Figure 3) upwards from the seat so that the aperture 39
between it and the outer spindle 7a begins to open.
Pressure in the chamber 5 increases and pushes the ~`irst
operating spindle up from the seat, so that the opening lO
and the conduit 12 are opened and the fluid starts flowing
from the cylinder S via the chamber S into the tank T. The
acceleration of the lift cage HS, F-G in Figure 2, is
adjusted to be constsnt by aid of the control unit 57 again
on the basis of the impulses received from the impulse
sensor 58, so that it remains suitable until the desired
descending speed G of the lift cage is achieved (Figure 2).
By employing the inner spindle 7b, an excellent
controllability of the system is achieved; the takeoff
downwards is carried out softly. If the countervalve 41 for
some reason i9 closed (error of the control unit, the
stepping motor breaks down etc.), the pressure in the
chamber 31 increases, and the inner spindle 7b begins to
close against the seat. However, this takes place in a
controlled manner, because there is fluid in between the
inner and the outer spindles 7a, 7b, and this fluid can
flow out both through the opening between the piston 7c of
the inner spindle 7b and the wall of the chamber 31, and
~6:3~9~
through the opening between the upper end oF the outer
spindle 7a and the wall of the chamber 31, both into the
chamber 31 and into the outlet conduit 19. Now the lift
cage HS stops softly. It is pointed out that while driving
upwar~s9 the spindles ~a and 7b function as one ~niform
entity.
The conduit 45 is advantageously connected to the chamber
5. The purpose of this arrangement is to prevent the
lû descending speed of the lift cage HS from growing too fast
in case the countervalve 41 should leak or be broken. In
that case the hydraulic pressure is now evened out over the
operating spindle 7 via the conduits ~û and ~5 into the
chamber 31.
By employing the valve apparatus of the invention, it is
easy to correct the changes and slide-downs that in the
cour~e of time take place in the position of the liFt cQge
with respect to the floor landings, which changes are due
to the changes in the temperature, and consequently in the
volume of the fluid. The impulse sensor 58, by aid of the
control unit 57, controls the position of the lift cage
with an accuracy of for instance -~1 mm. When a sufficiently
big change takes place in the position of the li-ft cage,
the control unit starts the pump P, and the lift cage HS is
lifted back into its proper position.
In case the lift cage ~IS should, for one reason or another,
stop in the middle of the drive, the control unit 57
returns the stepping motor 55 and the wobbler 56 attached
thereto into home position. The general procedure in the
case of faults is to return the stepping motor 55 and the
wobbler into home position. When the alarm button HP is
pressed in the lift ca~e, the stepping motor, controlled by
the control unit 57, winds the wobbler 56 into such a
~36~
21
predetermined position where the countervalve 41 i5 opened,
under the pressure of the pin-like head 47 of the spindle
46~ so much that the hydraulic pres~ure in the chamber 31
starts to decrease9 but not so much as -to li~t the inner
~pindle 7b apa~t from the outer spindle 7a. Now the
pressure in the cylinder S starts to go down, and the fluid
flows through the conduit 32, the chamber 31, the conduit
40, the countervalve 41 and the conduit 45 into the tank
T. The lift cage IIS descends slowly and safely downwards as
long as the alarm button HP is being pressed - generally
to the nearest floor below, where it is possible to get out
of the lift cage HS. Thus it is shown that another task of
the conduit 22 is, also while the lift cage HS is rising
upwards, to even out the hydraulic pressure of the chamber
31 towards the outlet conduit 19, when the operflting
spindle 7 rises up from its seat.
If the stepping motor 5S is destroyed, or there is an
interruption in the electric supply (the ele~ator is,
2û however, provided with a reserve power source, i.e. an
accumulator) or other fault in the electric circuitry, the
countervalve 41 is closed and its spring prssses the
spindle 46 into the direction A, so that the released
wobbler 56 is wound to home position, and simultanously the
lift cage HS is stopped.
The control unit 57 (as well as 17) comprises advantage-
ously and according to Figure 4: the data processing unit
proper, such as the microprocessor 63; the read only memory
ROM 64, where the permanent operating system is stored; the
random access memory RAM 65, where the variables and for
instance the specific information of each elevator is
stored; the timers T 66 for synchroni~ing the various
circuits; an UART circuit 67, whereby the control unlt 57
can be connected for instance to external computers; the
~3~
22
inlet circuits 68 and the opto-couplers 69 connected
thereto, via which couplers the messages from the call
buttons, the floor buttons, the approach and floor signals
etc. are transferred to be processed in the microprosessor
63; the outlet circuits 70 and the control circuits
connected thereto, for operating the actuator of the
throttle valve 42, i.e. the stepping motor 55, For
switching the pump P on and off and for giving external
alQrms etc. and~ in addition to this, for example for
supervising the control systems of the control circuits 72.
It i5 pointed out that the inner technical realization o~
the valve apparatus i-tself does not necessarily have to
resemble the embodiment presented in Figure 1 or 3, because
the conduits and the aeparate valves can be arran9ed in
many different ways, ànd their arrangement i9 mainly
dictsted by the requirements of the specific application in
question, as well as by the manufacturing technique. Thus
the above specification is by no means intended for
limiting the invention and its scope apart from what i9
claimed in the appended patent claims.
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