[0001] The present invention relates to a pressurized-medium system, which includes
- a pressurized-medium source,
- a double-acting actuating cylinder, which includes a feed line and a return line,
- a directional control valve for controlling the actuating cylinder,
- pressurized-medium conductors connected from the pressurized-medium source through
the directional control valve to the actuating cylinder and back,
- a booster cylinder, which is fitted between the directional control valve and the
actuating cylinder, and
- a pressure-controlled sequence valve fitted between the directional control valve
and the booster cylinder and connected to the booster cylinder in such a way that,
when the pressure increases in the feed line of the actuating cylinder over the setting
value of the pressure-controlled sequence valve, changes its position, feeding the
pressurized medium to the booster cylinder and from there to the actuating cylinder,
in order to increase the operating power of the actuating cylinder automatically,
- a pressure-controlled check valve arranged in the feed line to prevent the increased
pressure from escaping to the feed line when the pressure-controlled sequence valve
has changed its position,
- a pressure-controlled rapid-travel valve, which is arranged between the directional
control valve and the actuating cylinder for recirculating the pressurized medium
from the return line of the actuating cylinder to the feed line in order to increase
the work velocity, in such a way that, together with the pressure-controlled sequence
valve and the booster cylinder, three velocity and power ranges are formed in the
pressurized-medium system.
[0002] The invention also relates to a hydraulic splitter.
[0003] The pressurized-medium system according to the introduction is used, for example,
in applications, in which a large force is required momentarily.
US patent number 4659292 discloses one such system. A double-acting actuating cylinder is used normally controlled
by a directional control valve. If necessary, a booster cylinder is operated by a
control element, by means of which the pressure entering the actuating cylinder is
increased, in order to increase the operating power of the actuating cylinder. However,
the aforementioned system is complicated. In addition, the pressure boosting is based
on a very small cylinder, in which a small piston moves rapidly backwards and forwards.
Thus, the pressure rises slowly and the volume flow of the pressure medium is low,
in practice only a few decilitres per minute. At the same time, the velocity of the
actuating cylinder nearly stops, which is a significant drawback in many applications.
In addition, the pressurized medium is always fed through the booster cylinder, or
at least through the channels in it, which increase the flow resistance and causes
power losses and overheating. The small channels and high pressure generally require
the use of a special oil, which further increases costs.
[0004] JP S63 72904 discloses a pressurized-medium system according the preamble of the Claim 1.
[0005] The invention is intended to create a new type of pressurized-medium system, by means
of which a combination of a rapid work movement and high power can be achieved in
a small and compact size. In addition, the invention is intended to create a new type
of pressurized-medium component, by means of which the power of the pressurized-medium
system can be increased simply. Further, the invention is intended to create a new
type of hydraulic splitter, which will be more versatile, faster, and efficient than
previously, while being easier to operate than previously. The characteristic features
of the pressurized-medium system according to the present invention are stated in
the accompanying Claims 1. Correspondingly, the characteristic features of the hydraulic
splitter according to the invention are stated in the accompanying Claim 10. In the
pressurized-medium system according to the invention, hereinafter more simple in the
system, control of a surprisingly simple construction but versatile operation, combined
with an additional component providing additional operating power, is used. The control
is preferably automatic, with the velocity and power of the system changing according
to the current situation. Thus, the system is easy to use and above all fast and efficient.
[0006] Such a system has previously been impossible to achieve, or at least it has required
complicated and expensive structures and control technology. The pressurized-medium
component according to the invention is a compact totality, which can be placed in
different types of system, to increase the operating power. In the hydraulic splitter,
a combination of a rapid work movement and a high power is achieved, which accelerates
working, while there is sufficient power for splitting even large logs of wood.
[0007] In the following, the invention is described in detail with reference to the accompanying
drawings showing some embodiments of the invention, in which
- Figure 1
- shows the system according to the invention fitted to a hydraulic splitter,
- Figure 2
- shows the circuit diagram of a first embodiment of the system according to the invention,
- Figure 3
- shows a partial cross-section of the operating elements of the system according to
the invention,
- Figure 4
- shows the circuit diagram of a second embodiment of the system according to the invention,
and
- Figure 5
- shows schematic power and velocity curves of the system according to the invention,
as a function of pressure.
[0008] Figure 1 shows the system according to the invention in a hydraulic splitter. Here,
only part of the body 10 is shown, in which a ram 11 and a splitting wedge 12 are
arranged. The position and height of the splitting wedge can be adjusted, in order
to divide the wood into more than two parts. In Figure 1, the ram 11 is in the retracted
position, so that a log of wood 13 can be placed between the ram 11 and the splitting
wedge 12. Except for the ram, the moving parts of the hydraulic splitter are entirely
inside a protective casing, though in Figure 1 the protective casing is not shown.
The actuating cylinder 14 moving the ram 11 is located inside the ram 11 while the
piston rod of the actuating cylinder 14 is attached to the front end of the ram 11.
The other end of the actuating cylinder is attached to the body 10. Thus, the working
stroke of the actuating cylinder causes the ram to push the log against the splitting
wedge. Once the log has been split, the ram 11 is returned into the retracted position.
[0009] The hydraulic wood splitter is also referred to as a wood-billet machine. The maximum
force is dimensioned mainly on the basis of the size of the hydraulic splitter and
the size of the wood it splits, as well as the required splitting length. In practice,
the greater the diameter of the hydraulic cylinder, the slower the splitting speed.
Correspondingly, with a small hydraulic cylinder a rapid work stroke will be achieved,
but the splitting force will remain modest. The same problem is also in other applications,
in which a long and rapid work stroke, with a high power is also required. A hydraulic
splitter equipped with the booster cylinder described in the introduction would be
expensive and complicated, and hopelessly slow.
[0010] Figure 2 shows the construction of the system, and particularly its circuit diagram,
in greater detail. First of all, the system includes a pressurized-medium source 15,
which in a hydraulic splitter is a hydraulic pump rotated by an electric motor, or
the hydraulic output (not shown) of a work machine, such as a tractor. In Figure 2,
the pressurized-medium source 15 is shown with an arrow, next to which is a symbol
indicating the pressurized-medium tank. In addition, the system includes a double-acting
actuating cylinder 14, equipped with a feed line 16 and return line 17, as well as
a directional control valve 18 for controlling the actuating cylinder 14. In this
case, the directional control valve is of a type that is normally closed. Thus, in
order to control the actuating cylinder, the state of the directional control valve
must be changed (for example, manually).
[0011] In order to circulate the pressurized medium, the system includes pressurized-medium
conductors 19, which are connected from the pressurized-medium source 15 through the
directional control valve 18 to the actuating cylinder 14 and back. Thus, the pressure
of the pressurized-medium source can pressurize the actuating cylinder and direct
it forwards and backwards. The system further includes a booster cylinder 21, which
is fitted between the directional control valve 18 and the feed line 16 of the actuating
cylinder 14. The booster cylinder can be used to increase the maximum pressure of
the pressurized-medium source, so that the actuating cylinder will receive a higher
pressure than before. At the same time, the available power increases. The system
further includes a control element 37 fitted between the directional control valve
18 and the booster cylinder 21, in order to guide the pressurized medium to the booster
cylinder 21 when required and from it on to the actuating cylinder 14, in order to
increase the operating power of the actuating cylinder 14. The construction of the
control element is dealt with in greater detail later.
[0012] According to the invention, the system further includes a rapid-travel valve 20,
which is arranged between the directional control valve 18 and the actuating cylinder
14, in order to recirculate the pressurized medium from the return line 17 of the
actuating cylinder to the feed line 16, in order to increase the velocity of the actuating
cylinder 14, in such a way that, together with the control element 37 and the booster
cylinder 21, three movement velocity and power zones P1, P2, and P3 (Figure 5) are
created in the pressurized-medium system. By using suitable components and combinations
of them, the system can additionally be made to operate automatically. In other words,
the velocity and through it the power both increase and decrease, without any action
by the operator. In practice, the rapid-travel valve connects the piston and piston-rod
side of the actuating cylinder to each other in the operating-pressure range in the
forward motion, without affecting the return motion of the of the actuating cylinder.
Thus, the forward motion of the actuating cylinder is accelerated in the ratio of
the surface areas of the piston and the piston rod. In other words, in the central
position not controlled by the rapid-travel valve, the return line and the feed line
are connected to each other. In the embodiment shown in Figure 2, the use of the rapid-travel
valve doubles the velocity of the work movement in the operating-pressure range. The
rapid-travel valve is preferably of a type that opens automatically at a specific
pressure, as in Figure 2, or a mechanical type that is manually operated (not shown).
The rapid-travel valve can also be operated by control logic. The control element
too can be a valve that opens automatically at a specific pressure or a mechanical,
manually operated valve (not shown), or it can also be operated by control logic.
[0013] In the embodiment of the system shown, there is also a pressure-controlled sequence
valve 22 fitted between the rapid-travel valve 20 and the booster valve 21, which
acts as the control element 37 according to the invention. In this case, the pressure-controlled
sequence valve 22 is connected to the booster cylinder 21 in such a way that, when
the pressure rises over the setting value of the pressure-controlled sequence valve
22 in the feed line 16 of the actuating cylinder 14, it changes the valve's position,
thus feeding the pressurized medium to the booster cylinder 21 and from it on to the
actuating cylinder 14, in order to increase the operating power. Thus the pressure
increase is entirely automatic. The sequence valve is also referred to as a priority
or monitoring valve. The counter-pressure compensated sequence valve admits the pressurized
medium behind the piston of the booster cylinder, if the power of the actuating cylinder
threatens to run out. The system, as well as its individual components, can also be
controlled manually, or, for example, by control logic, which uses, for example, electrical
or pneumatic operating elements. However, the described embodiment of the system operates
automatically. The operator only needs to control the direction of movement using
the directional control valve, the control of which can also be made partly or entirely
automatic, for example, using a limit switch or a pressure transmitter. On the other
hand, the system described operates completely without sensors or meters. This helps
to reduce the system's manufacturing and operating costs. In addition, the valves
are durable and maintenance-free.
[0014] By means of the system described above, many advantages are gained. The system is
particularly advantageous in applications, which mainly require a rapid work movement,
but only momentarily great power. By combining the actuating cylinder, booster cylinder,
and control element, a large and slow actuating cylinder, or two parallel actuating
cylinders can be replaced with a system that is twice as fast, but nevertheless achieves
the same power. In addition, the system becomes compact and the control is versatile,
as well as being easily automated and adjusted. The operation of the system is described
in greater detail later.
[0015] A second embodiment of the system is shown in Figure 4, in which the rapid-travel
valve 20 is formed of two non-return valves and a pressure-controlled sequence valve,
in place of the three-position directional control valve and pressure-controlled sequence
valve of Figure 2. Otherwise, the construction and operation of Figure 4 correspond
to those of the system of Figure 2. In this case, there is additionally a measurement
point M in the valve block 23 for pressure measurements. Normally the pressure line
in question is plugged.
[0016] Figure 3 shows the pressurized-medium component according to the invention, which
is arranged to be connected to the pressurized-medium system. In this case, both the
actuating cylinder 14 and the booster cylinder 21 are shown at the start of their
work stroke. According to the invention, the work strokes of the actuating cylinder
14 and the booster cylinder 21 are arranged to be in opposite directions. Thus, the
forces caused by the movements of the pistons are, at least partly, cancelled out,
which reduces vibration and otherwise reduces the loading of the system. In Figure
3, the directions of movement of the cylinders are shown with arrows. In addition,
the actuating cylinder 14 and the booster cylinder 21 are arranged essentially parallel
to each other and attached to each other. Thus, the actuating cylinder can be used
to support the booster cylinder. Thus, a conventional actuating cylinder, for example,
can be easily replaced with the pressurized-medium component according to the invention.
[0017] The pressurized-medium component further includes a rapid-travel valve 20, which
according to the invention is fitted to the same valve block 23 as the pressure-controlled
sequence valve 22. The valve block 23 becomes apparent especially in Figure 3, in
which the connections of the valve block are indexed according to Figure 2. Here,
the pressurized-medium conductor is a pressure line 24 from the pressurized-medium
source, which is connected to the connector D1. Correspondingly, the tank line 25
is connected to the connector D2. The feed line of the actuating cylinder 14 is connected
to the connector U2 and the return line 17 to the connector U1. The fifth connector
is B2, which is connected to the feed line 16' of the booster cylinder 21. In addition,
the high-pressure side of the booster cylinder 21 is connected by a T-connector directly
to the feed line of the actuating cylinder 14 and the low-pressure-side return line
26 by a connector to the return line 17 of the actuating cylinder 14. Thus, as little
as possible high-pressure-resistant piping is required. In this application, the piping
in question is only from the connector U2 of the valve block 23 to the actuating cylinder
14. The other pressurized-medium conductors can be dimensioned according to the non-boosted
maximum pressure.
[0018] In Figure 3, the valve block 23 is shown slightly separate from the actuating cylinder
and the booster cylinder. According to the invention, the valve block can be supported
on the booster cylinder, in which case an even more compact construction will be formed.
In addition, the valve block can even be integrated as part of the booster cylinder,
in which case a single unified pressurized-medium component will be formed. Existing
systems can be easily upgraded using the new type of component. However, when creating
a new system, it is preferable to use a thick-walled actuating cylinder. In other
words, the wall of the actuating cylinder is thicker than usual, so that it is possible
to exploit the considerably higher pressure than the normal operating pressure, created
by the booster cylinder. Example calculation are given later.
[0019] Figure 3 also shows the new type of construction of the booster cylinder. According
to the invention, the booster cylinder 21 is formed of a low-pressure part 28 and
a high-pressure part 29, which are connected end-to-end by an intermediate piece 30,
as a continuation of each other. The construction in question is simple to manufacture,
because the walls of the low-pressure part and the high-pressure part can be made
from tube blanks of different wall thicknesses, which are then joined to each other
by the intermediate piece. Naturally, the wall of the high-pressure part is thicker
than the wall of the low-pressure part. In addition to the double construction, the
booster cylinder also differs in terms of the creation of the pressure. According
to the invention, the increased pressure is made purely with the aid of the piston
rod of the low-pressure part protruding into the high-pressure part, without a separate
piston. This simplifies the construction, facilitates sealing, and increases durability.
In practice, normal seals are sufficient to seal the piston rod. More specifically,
the low-pressure part 28 includes a piston 31, which is equipped with a piston rod
32 sealed to the intermediate piece 30, and which is arranged to form the functional
piston of the high-pressure part 29. The pressure increase is influenced mainly by
the ratio of the surfaced areas of the piston rod and the piston. The piston 33 and
the piston rod 34 of the actuating cylinder 14 are shown partly in Figure 3.
[0020] One advantageous application is precisely the hydraulic splitter shown in Figure
1, which includes a body 10 and a splitting wedge in it, as well as a ram 11, for
the operation of which the hydraulic splitter includes the pressurized-medium system
according to the invention. The actuating cylinder 14 and booster cylinder 21 belonging
to the pressurized-medium system are preferably attached to each other and arranged
inside the ram 11. Thus, the compact package is protected inside the ram. In addition,
the hydraulic splitter can be upgraded by replacing the original actuating cylinder
with a new actuating cylinder equipped with a even thicker wall and with the pressurized-medium
component according to the invention. As a result, three automatically operating velocity
and power ranges are obtained, which makes the hydraulic splitter on the one hand
fast, but on the other powerful, without complicated and large structures.
[0021] In the hydraulic splitter shown, the actuating cylinder is, as such, a conventional
double-acting hydraulic cylinder, but it is equipped with a cylinder tube that has
a thicker wall than normal. In this case, a pressurized-medium component boosting
the pressure is installed on top of the actuating cylinder. The booster cylinder can
also be alongside the actuating cylinder. In the system according to the invention,
unlike in known applications, the pressure is boosted purely by pushing the low-pressure
part piston rod into the oil chamber of the high-pressure part. From the high-pressure
part, the boosted-pressure oil is led into the reinforced actuating cylinder, so that
a greater operating power than before is achieved without altering the capacity of
the pressurized-medium source.
[0022] The magnitude of the boosted pressure is determined by the ratio of the surface areas
of the low-pressure part's piston rod and piston. The boosted pressure is used mainly
only when additional power is momentarily required. In the embodiment shown, during
each stroke of the actuating cylinder the boosted pressure is available over a distance
of about 100 mm.
[0023] The hydraulic splitter is controlled like a normal double-acting hydraulic cylinder
with the aid of a backward-forward directional control valve (Figure 2). The directional
control valve is used to guide the flow to the valve block according to the invention,
which controls the system automatically between three velocities and powers, depending
on the power required. The valve block according to the invention forms a valve unit,
by means of which three separate operating valves are combined to form a single compact
unit. The unit is small in size and the number of external pipes and hoses remains
as small as possible. Despite the boosted pressure, expensive high-pressure hoses
are not necessarily required at all, thanks to the valve unit. Thus, the structure
of the system according to the invention is compact and simple.
[0024] The actuating cylinder operates in the same manner as a normal double-acting hydraulic
cylinder. In the following example, a system is examined, in which the maximum pressure
of the pressurized-medium source is 180 bar. As the resistance is low, the actuating
cylinder operates with so-called rapid travel, so that the oil on the piston-rod side
is circulated through a rapid-travel valve in the valve block, to behind the piston.
The rapid travel is fast, but only a force according to the surface area of the piston
rod of the actuating cylinder is available for use. In this example, the operating
range of the rapid travel is 0 - 130 bar. In Figure 5, this is the velocity and power
range P1. As the pressure rises, the power also increases while the velocity remains
essentially the same. Once the oil pressure in the system rises above 130 bar, the
rapid travel automatically disconnects. In other words, being pressure-controlled,
the rapid-travel valve changes its position, when the oil begins to circulate from
the piston-rod side to the tank and the pressurized oil goes behind only the piston.
At the same time, the velocity of the actuating cylinder slows to one half, but the
power is doubled. This operating range is, for example, 130 - 160 bar and is the velocity
and power range P2 in Figure 5. The mutual relationships of the velocity and power
ranges depend mainly on the dimensioning of the actuating cylinder and the booster
cylinder and the settings of the system. As the resistance continues to increase,
the pressure continues to rise in the system. In the example, at a pressure of 160
bar, the power of the actuating cylinder threatens to end, because the maximum pressure
of the pressurized-medium source is approaching. In this situation, the booster cylinder
is brought into operation. However, the actuating cylinder continues to progress,
because there is still 20 bar available of the maximum pressure of the pressurized-medium
source. According to its setting value, the sequence valve in the valve unit opens
at a pressure of 160 bar and releases oil behind the booster piston and begins to
push the piston rod into the oil chamber of the high-pressure part, in which the pressure
is 160 bar. At the same time, the pressure begins to rise not only in the oil chamber
of the high-pressure part, but also in the feed line of the actuating cylinder, and
then on the piston side of the actuating cylinder. Due to the increase in pressure,
the pressure-controlled check valve 35 in the valve unit closes immediately due to
the pressure difference and raises the pressure in the actuating cylinder to 440 bar,
at the same time as there is a pressure of 180 bar behind the piston in the booster
cylinder. The pressure-controlled check valve prevents the increased pressure from
escaping to the tank through the system's pressure-limit valve. At the same time,
the velocity of the actuating cylinder roughly halves, but the power increases to
about double. In Figure 5, this is the velocity and power range P3. On the basis of
the above, the setting value of the pressure-controlled sequence valve is set to 5
- 20 %, preferably 10 - 15 % lower than the maximum pressure of the pressurized-medium
source. Thus, the movement of the actuating cylinder continues without stopping, as
the control of the system operates automatically.
[0025] If the resistance gives way, the valves located in the valve block once again control
the actuating cylinder according to the prevailing pressure range. The actuating cylinder
then returns to its normal velocity or to rapid travel. The return movement of the
actuating cylinder operates rapidly in the manner of a normal double-acting cylinder.
In the return movement, first of all the piston of the booster cylinder returns and
then the piston of the actuating cylinder starts moving. The booster cylinder is then
made to operate rapidly backwards and forwards, if the reinforcement distance already
achieved is insufficient. In other words, the booster cylinder is made to return rapidly
and to continue the work movement with a new boosting stroke.
[0026] The following are theoretical powers and velocities of the actuating cylinder, calculated
from the embodiment examples. The calculations are based on a maximum pressure of
180 bar in the pressurized-medium source, the volume flow being 40 l/min. In this
case, the diameter of the piston of the actuating cylinder is 50 mm, the diameter
of the piston rod being 35 mm. Correspondingly, the diameter of the piston rod of
the booster cylinder is 32 mm. Thus, the pressure boosting ratio is 2,44. In addition,
the length of stroke of the booster cylinder is 240 mm, the length of stroke of the
actuating cylinder being 680 mm. At these values, during the rapid travel, a force
of about 1700 kg and the forward length of stroke lasts 0,98 s with the rapid travel.
Correspondingly, during the basic movement, a force of about 3500 kg is achieved and
the forward length of stroke lasts 2,00 s with the basic movement. With the dimensioning
described, a one-off stroke of about 100 mm at a boosted pressure is achieved. At
a pressure of 440 bar, a force of about 8600 kg is achieved. Thanks to the rapid travel,
the total movement is accelerated by about one third. In other words, when the return
movement lasts about one second, the entire work stroke with rapid travel lasts about
two seconds, when with a basic movement it would last about three seconds. In practice,
the system described has three velocities and powers and its operation is regulated
automatically according to the load. The rapid-travel velocity operates in the pressure
range 0 - 130 bar, when the available force is 0 - 1700 kg. The normal velocity operates
in the pressure range 130 - 160 bar, when the available force is 1700 - 3500 kg. The
third velocity operates during pressure boosting. The pressure range is then 160 -
440 bar, the available power being 1700 - 8600 kg. On the basis of the above, the
use of a piston diameter of 50 mm achieves a force corresponding to a conventional
piston diameter of 75 mm. Even with the rapid travel, the backwards and forwards movement
of the larger diameter cylinder would take five seconds, when according to the invention
it is only two seconds. On the other hand, by increasing the piston diameter of the
actuating cylinder to 75 mm, a force of 8000 - 16 000 kg would be achieved using the
system described. In the graph of Figure 5, the pressure of the system is on the X-axis
and the force achieved by the actuating cylinder is on the left-hand Y-axis. On the
right-hand Y-axis is the relative velocity of the actuating cylinder. The graphs are
not based on precisely absolute values, but mainly show the operating principle of
the system according to the invention.
[0027] In addition to specific types of components, their dimensioning is important in terms
of the operation of the system. At the above values, 40 l/min of oil flows through
connector D2 during the work stroke and 80 l/min during the return movement. A 3/4"
hose is connected to the connector in question. Correspondingly, 20 l/min of oil flows
through connector D1 during the work stroke and 40 l/min during the return movement.
A 1/2" hose is connected to the connector in question. Due to the increased pressure,
a thick-walled pipe, with an internal diameter of 15 mm, is connected to the connector
U2. Correspondingly, a thinner-walled pipe, with an internal diameter of 12 mm, is
sufficient for the connectors B2 and U1. In addition, the connector opening 36 of
the feed line 16 of the actuating cylinder 14 is made to be spacious, so that during
the return movement a large amount of oil can flow through it without unnecessary
throttling. In other words, there are small pressure losses in the system, due to
the correctly dimensioned piping and flow openings.
[0028] The above description is of a system using oil as the pressurized medium, which is
also suitable for pneumatics or water hydraulics. In addition to a hydraulic splitter,
the system can also be applied, for instance, in other applications requiring a long
and rapid work stroke, but from time to time also large forces. Such are, for example,
presses and the operating devices of large valves. For example, in cardboard or waste
presses, a significant part of the work stroke of the actuating cylinder is nearly
without resistance. Only when the receptacle becomes full does the resistance increase.
However, the actuating cylinder and the entire mechanism must, as is known, be dimensioned
according to the maximum resistance. Thus, a known waste press is slow. By means of
the system according to the invention, it is possible to use an actuating cylinder
that is smaller than previously, which can, in addition, be run using rapid travel.
The waste press will then become considerably fast and there will be sufficient power
to press the waste. The configuration of the system can vary in different applications.
For example, a single booster cylinder can be used to boost the working pressure of
several actuating cylinders. Such an application is, for example, a punch press, in
which there are several actuating cylinders at different work stages. On the other
hand, the booster cylinder can be located far from the actuating cylinder. In that
case, in cranes, for example, a clearly smaller actuating cylinder can be located
high among the booms, with the booster cylinder being in the lower part of the booms.
This increases the effective power of the crane and improves its stability. With suitable
variations, the system according to the invention can even boost the pressure led
to a hydraulic motor. This will increase, for example, the efficiency of mobile equipment,
as a smaller machine unit will be sufficient to produce pressure.
[0029] In addition, the system can be used to replace existing devices containing two or
more actuating cylinders. Now, in the system according to the invention, the rapid
travel of the actuating cylinder operates, even though a booster cylinder is available.
Due to the addition power achieved by the booster cylinder, the piston diameter of
the actuating cylinder can be kept advantageously small. The movement of the actuating
cylinder then remains rapid and further the return movement is even more rapid. The
system according to the invention is simple, fast, and fully automatic. The actuating
cylinder starts to move immediately with a rapid travel and changes to a normal velocity
as the resistance increases. At the same time, the velocity slows, but the power increases.
Only when the resistance continues to increase the oil flows, again advantageously
automatically, to the booster cylinder. The velocity of the actuating cylinder then
slows again, but the power continues to increase. The boosted pressure is fed to the
actuating cylinder until the resistance eases, when the actuating cylinder changes
to normal velocity and then to rapid travel, if the resistance continues to ease.
The system according to the invention is optimized according to power and velocity.
The actuating cylinder never stops in mid-stroke, but instead automatically changes
velocity and power. The use of the system also saves energy. For example, in a situation,
in which a maximum pressure of 200 bar is required, it has been necessary to use a
15-kW motor. Now, with the aid of the invention, 100 bar is enough, which, if necessary,
can be boosted by the booster cylinder to 200 bar and even higher. The 100-bar feed
pressure is achieved using a 7,5-kW motor. At the same time, a faster, three-step
movement is achieved. The features of the invention can also be exploited the other
way round. An existing system can be made more powerful by equipping it with a booster
cylinder and valves according to the invention. Pressure boosting is also referred
to as stepping up pressure.
1. Pressurized-medium system, which includes
- a pressurized-medium source (15),
- a double-acting actuating cylinder (14), which includes a feed line (16) and a return
line (17),
- a directional control valve (18) for controlling the actuating cylinder (14),
- pressurized-medium conductors (19) connected from the pressurized-medium source
(15) through the directional control valve (18) to the actuating cylinder (14) and
back,
- a booster cylinder (21), which is fitted between the directional control valve (18)
and the actuating cylinder (14), and
- a pressure-controlled sequence valve (22) fitted between the directional control
valve (18) and the booster cylinder (21) and connected to the booster cylinder (21)
in such a way that, when the pressure increases in the feed line (16) of the actuating
cylinder (14) over the setting value of the pressure-controlled sequence valve (22),
changes its position, feeding the pressurized medium to the booster cylinder (21)
and from there to the actuating cylinder (14), in order to increase the operating
power of the actuating cylinder (14) automatically,
- a pressure-controlled check valve (35) arranged in the feed line (16) to prevent
the increased pressure from escaping to the feed line (16) when the pressure-controlled
sequence valve (22) has changed its position,
- a pressure-controlled rapid-travel valve (20), which is arranged between the directional
control valve (18) and the actuating cylinder (14) for recirculating the pressurized
medium from the return line (17) of the actuating cylinder (14) to the feed line (16)
in order to increase the work velocity, in such a way that, together with the pressure-controlled
sequence valve (22) and the booster cylinder (21), three velocity and power ranges
(P1, P2, P3) are formed in the pressurized-medium system, characterized in that :
- the pressure-controlled check valve (35) is located between the double-acting cylinder
(14) and the pressure-controlled rapid-travel valve (20);
- the pressure-controlled rapid-travel valve (20) the pressure-controlled sequence
valve (22) and the pressure-controlled check valve (35) are arranged in the same valve
block (23);
- the directions of the work strokes of the actuating cylinder (14) and the booster
cylinder (21) are arranged to be opposite to each other; and in that
- the actuating cylinder (14) and the booster cylinder (21) are arranged essentially
parallel to each other and are attached to each other.
2. Pressurized-medium system according to Claim 1 characterized in that the directional control valve (18) includes control that is implemented manually
or using an operating device.
3. Pressurized-medium system according to any of Claims 1-2 characterized in that the setting value of the pressure-controlled sequence valve (22) is set to be 5 -
20 %, preferably 10 - 15 % lower than the maximum pressure of the pressurized-medium
source (15).
4. Pressurized-medium system according to any of Claims 1-3, characterized in that the valve block (23) is supported on, or integrated in the booster cylinder (21).
5. Pressurized-medium system according to any of Claims 1-4, characterized in that the actuating cylinder (14) is thick walled.
6. Pressurized-medium system according to any of Claims 1-5, characterized in that the booster cylinder (21) is formed of a low-pressure part (28) and a high-pressure
part (29), which are joined end-to-end by an intermediate piece (30) as an extension
of each other.
7. Pressurized-medium system according to Claim 6, characterized in that the low-pressure part (28) includes a piston (31), which is equipped with a piston
rod (32), which is sealed to the intermediate piece (30), and which is arranged functionally
as the piston of the high-pressure part (29).
8. Hydraulic splitter, which includes a body (10) and a splitting wedge (12) in it, as
well as a ram (11), in order to operate which the hydraulic splitter includes a pressurized-medium
system, characterized in that the pressurized-medium system is according to any of Claims 1-7.
9. Hydraulic splitter according to Claim 8, characterized in that the actuating cylinder (14) and booster cylinder (21) belonging to the pressurized-medium
system are attached to each other and arranged inside the ram (11).
1. Ein Druckmittelsystem, zu dem gehören
- eine Druckmittelquelle (15),
- ein doppeltwirkender Steuerzylinder (14), zu dem eine Zulaufleitung (16) und eine
Rücklaufleitung (17) gehören,
- ein Wegeventil (18) zur Regelung des Steuerzylinders (14),
- Druckmittelleitungen (19) verbunden von einer Druckmittelquelle (15) über ein Wegeventil
(18) zu einem Steuerzylinder (14) und zurück,
- ein Druckverstärkungszylinder (21), der zwischen dem Wegeventil (18) und dem Steuerzylinder
(14) angeordnet ist, und
- ein zwischen dem Wegeventil (18) und dem Druckverstärkungszylinder (21) angeordnetes
druckgesteuertes Sequenzventil (22), das mit dem Druckverstärkungsventil (21) auf
der Weise verbunden ist, dass es (das Sequenzventil) bei einem Druckanstieg in der
Zulaufleitung (16) des Steuerzylinders (14) über den Einstellwert des druckgesteuerten
Sequenzventils (22) seine Position ändert und Druckmittel in den Druckverstärkungszylinder
(21) einführt und von dort weiter zum Steuerzylinder (14), um dessen Betriebsleistung
automatisch zu erhöhen,
- ein in der Zulaufleitung (16) angeordnetes druckgesteuertes Rückschlagventil (35)
zur Vermeidung eines Entweichens des erhöhten Druck in die Zulaufleitung (16), wenn
das druckgesteuerte Sequenzventil (22) seine Position geändert hat,
- ein druckgesteuertes schnelles Stellventil (20), das zwischen dem Wegeventil (18)
und dem Steuerzylinder (14) angeordnet ist, zur Rückführung des Druckmittels von der
Rücklaufleitung (17) des Steuerzylinders (14) zur Zulaufleitung (16), um die Arbeitsgeschwindigkeit
auf der Weise zu erhöhen, dass zusammen mit dem druckgesteuerten Sequenzventil (22)
und dem Druckverstärkungszylinder (21) drei Geschwindigkeits- und Leistungsbereiche
(P1, P2, P3) im Druckmittelsystem gebildet werden,
dadurch gekennzeichnet, dass
- das druckgesteuerte Rückschlagventil (35) zwischen dem doppeltwirkenden Steuerzylinder
(14) und dem druckgesteuerten schnellen Stellventil (20) angeordnet ist,
- das druckgesteuerte schnelle Stellventil (20), das druckgesteuerte Sequenzventil
(22) und das druckgesteuerte Rückschlagventil (35) im selben Ventilblock (23) angeordnet
sind,
- die Richtungen der Arbeitsbewegungen vom Steuerzylinder (14) und Druckverstärkungszylinder
(21) einander entgegengesetzt angelegt sind; und dass
- der Steuerzylinder (14) und der Druckverstärkungszylinder (21) wesentlich parallel
zueinander angeordnet sind und miteinander befestigt sind.
2. Druckmittelsystem gemäß dem Patentanspruch 1, dadurch gekennzeichnet, dass zum Wegeventil (18) eine manuelle Steuerung oder eine Steuerung mit Stellantrieb
gehören.
3. Druckmittelsystem gemäß einem der Patentansprüche 1 - 2, dadurch gekennzeichnet, dass der Einstellwert des druckgesteuerten Sequenzventils (22) um 5 - 20%, vorzugsweise
um 10 - 15% niedriger eingestellt ist als der Maximaldruck der Druckmittelquelle (15).
4. Druckmittelsystem gemäß einem der Patentansprüche 1 - 3, dadurch gekennzeichnet, dass der Ventilblock (23) am Druckverstärkungszylinder (21) gestützt oder in ihm integriert
ist.
5. Druckmittelsystem gemäß einem der Patentansprüche 1 - 4, dadurch gekennzeichnet, dass der Steuerzylinder (14) dickwandig ist.
6. Druckmittelsystem gemäß einem der Patentansprüche 1 - 5, dadurch gekennzeichnet, dass der Druckverstärkungszylinder (21) aus einem Niederdruckteil (28) und einem Hochdruckteil
(29) besteht, die mit Hilfe eines Zwischenstücks (30) an ihren Enden einander als
Verlängerung verbunden sind.
7. Druckmittelsystem gemäß dem Patentanspruch 6, dadurch gekennzeichnet, dass zum Niederdruckteil (28) ein Kolben (31) gehört, der mit einer Kolbenstange (32)
ausgerüstet ist, die an dem Zwischenstück (30) abgedichtet ist und die als funktionaler
Kolben am Hochdruckteil (29) angeordnet ist.
8. Ein Hydraulikspalter, zu dem ein Rahmen (10) und darin eine Spaltklinge (12) sowie
ein Stoßschlitten (11) gehören, um diesen in dem Hydraulikspalter einzusetzen, gehört
dazu ein Druckmittelsystem, dadurch gekennzeichnet, dass das Druckmittelsystem einem der Patentansprüche 1 - 7 entspricht.
9. Ein Hydraulikspalter gemäß dem Patentanspruch 8, dadurch gekennzeichnet, dass der zum Druckmittelsystem gehörende Steuerzylinder (14) und der Druckverstärkungszylinder
(21) miteinander verbunden sind und im Stoßschlitten (11) angeordnet sind.
1. Système à fluide pressurisé, qui comprend
- une source de fluide pressurisé (15),
- un vérin d'actionnement à double effet (14), qui comprend une conduite d'alimentation
(16) et une conduite de retour (17),
- une vanne de commande directionnelle (18) pour le contrôle du vérin d'actionnement
(14),
- des conducteurs pour le fluide pressurisé (19) reliés depuis la source de fluide
pressurisé (15) via la vanne de commande directionnelle (18) au vérin d'actionnement
(14) et dans le sens inverse,
- un cylindre multiplicateur de pression (21), qui est disposé entre la vanne de commande
directionnelle (18) et le vérin d'actionnement (14), et
- une soupape de séquence commandée par pression (22) disposée entre la vanne de commande
directionnelle (18) et le cylindre multiplicateur (21) et reliée au cylindre multiplicateur
(21) de sorte que, lorsque la pression dans la conduite d'alimentation (16) du vérin
d'actionnement (14) dépasse la valeur de réglage de la soupape de séquence commandée
par pression (22), elle change sa position, fournissant le fluide pressurisé au cylindre
multiplicateur (21) et de là au vérin d'actionnement (14), pour augmenter automatiquement
la puissance de fonctionnement du vérin d'actionnement (14),
- un clapet anti-retour commandé par pression (35) disposé dans la conduite d'alimentation
(16) pour éviter que la pression augmentée ne s'échappe dans la conduite d'alimentation
(16) quand la soupape de séquence commandée par pression (22) a changé de position,
- une soupape rapide commandée par pression (20), qui est disposée entre la vanne
de commande directionnelle (18) et le vérin d'actionnement (14) pour recirculer le
fluide pressurisé depuis la conduite de retour (17) du vérin d'actionnement (14) à
la conduite d'alimentation (16) pour augmenter la vitesse de travail, de sorte qu'en
combinaison avec la soupape de séquence commandée par pression (22) et le cylindre
multiplicateur (21) trois gammes de vitesse et de puissance (P1, P2, P3) sont formées
dans le système à fluide pressurisé,
caractérisé en ce que :
- le clapet anti-retour commandé par pression (35) est situé entre le vérin à double
effet (14) et la soupape rapide commandée par pression (20);
- la soupape rapide commandée par pression (20), la soupape de séquence commandée
par pression (22) et le clapet anti-retour commandé par pression (35) sont disposés
dans le même bloc de soupapes (23);
- les sens des courses de travail du vérin d'actionnement (14) et du cylindre multiplicateur
(21) sont disposés de sorte qu'ils soient opposés l'un à l'autre ; et en ce que
- le vérin d'actionnement (14) et le cylindre multiplicateur (21) sont disposés essentiellement
parallèles l'un à l'autre et sont attachés l'un à l'autre.
2. Système à fluide pressurisé selon la revendication 1, caractérisé en ce que la vanne de commande directionnelle (18) comprend une commande réalisée manuellement
ou à l'aide d'un actionneur.
3. Système à fluide pressurisé selon l'une quelconque des revendications 1 à 2, caractérisé en ce que la valeur de réglage de la soupape de séquence commandée par pression (22) est réglée
de sorte à être de 5 à 20 %, de préférence de 10 à 15 % inférieure à la pression maximale
de la source du fluide pressurisé (15).
4. Système à fluide pressurisé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que le bloc de soupapes (23) est soutenu par ou intégré dans le cylindre multiplicateur
(21).
5. Système à fluide pressurisé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que le vérin d'actionnement (14) est muni de parois épaisses.
6. Système à fluide pressurisé selon l'une quelconque des revendications 1 à 5, caractérisé en ce que le cylindre multiplicateur (21) est composé d'une partie à basse pression (28) et
d'une partie à haute pression (29) qui sont rattachées bout à bout l'une dans le prolongement
de l'autre à l'aide d'une pièce intermédiaire (30).
7. Système à fluide pressurisé selon la revendication 6, caractérisé en ce que la partie à basse pression (28) comprend un piston (31), qui est équipé d'une tige
de piston (32) scellée à la pièce intermédiaire (30), et qui est agencé du point de
vue fonctionnel en tant que piston de la partie à haute pression (29).
8. Fendeuse hydraulique, qui comprend un châssis (10) et un coin de fendage (12) dans
celui-ci, ainsi qu'un poussoir (11), pour l'utilisation duquel la fendeuse hydraulique
comprend un système à fluide pressurisé, caractérisée en ce que le système à fluide pressurisé est selon l'une quelconque des revendications 1 à
7.
9. Fendeuse hydraulique selon la revendication 8, caractérisée en ce que le vérin d'actionnement (14) et le cylindre multiplicateur (21) appartenant au système
à fluide pressurisé sont attachés l'un à l'autre et disposés à l'intérieur du poussoir
(11).