Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
CARTRIDGE TYPE PLASMA TORCH
Technical Field
The present invention relates to a cartridge type plasma
torch which is used for welding or cutting, and particularly relates
to a cartridge type plasma torch which allows expendables of the
10 plasma torch to be easily mounted therein and/or dismounted
therefrom.
Background Art
Plasma welding and plasma cutting have much higher
energy density, and are more excellent in operability compared to
the other machining methods (for example, TIG welding, and gas
cutting), thcrefore they are used in various fields. However, in
the conventional plasma torch which is used for plasma welding
and plasma cutting, replacement (mounting / dismounting) of
expendables such as a torch nozzle and an electrode is very
difficult compared to the other machining methods. For this
reason, its excellent operability is not fully utilized. In order to
eliminate the above disadvantage, various proposals have been
conventionally made, and some examples are as follows.
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A cassette type plasma torch, for example, as shown in
Figs. 7, 8A, and 8B is described in Japanese Patent Application
Publication No. 3-27309, Japanese Utility Model Application
Laid-open No. 62-96967, and Japanese Utility Model Application
6 Laid-open No. 62-96968. The cassette type plasma torch
consists of a torch main body 51 and a torch head 52. The torch
main body 51 includes a cooling water supply conduit line 68a, a
cooling water discharge conduit line 54, a reactant gas supply
conduit line 55, and a high frequency stand 56. The torch head
10 52 includes a plasma arc injection port 53, a torch cap 34, a torch
nozzle 3, an electrode 4, a water conduit line 68, and the like.
The torch main body 51 is separable from the torch head 52, and
the torch head 52 is attached at the front-end portion of the torch
main body 51 by screwing a cassette screw 61 which is provided
15 at the periphery of the front-end portion of the torch main body 51
and a cylindrical cassette screw 61 which is provided at the base
end portion side of the torch head 52. With a single motion of
screwing in or unscrewing the aforementioned cassette screw 62,
the torch head 52 is easily mounted in and / or dismounted from
20 the torch main body 51.
At this time, the base end portion (the side which is
inserted into the torch main body 51) of the torch head 52 is
formed in a cone form, and a plurality of seal portions 57, 58, and
59 in a tapering form are formed on the periphery surface of the
26 cone body. The front-end portion (the side which is in contact
CA 02237668 1998-0~-14
with the aforementioned base end portion of the torch head 52) of
the toreh main body 51 is formed in an inverted eone form
corresponding to the toreh head 52, and inverted tapering seal
portions 57a,58a, and S9a corresponding to the torch head 52 are
5 formed on the inner surface of the inverted cone body. Further,
in some cases, O-ring grooves are formed at the tapering seal
portions 57, 58, and 59 side of the base end portion of the
aforementioned torch head 52, or the inverted tapering seal
surfaces 57a, 58a, and S9a side of the front-end portion of the
torch main body 51, and O-rings 63, 64, and 65 are inserted into
the O-ring grooves.
As the result of inserting the torch head 52 in the front-
end portion of the torch main body 51 and screwing in the cassette
screw 62, the helmeticity among the cooling water supply conduit
line 68a, the cooling water discharge conduit line 54, and the
reactant gas supply conduit line SS is maintained at the
aforementioned junction portion in a tapering form. As for the
electrie eonnection between the torch main body 51 and the toreh
head 52, eleetric eurrent ean be applied through each of the
working faces of the tapering seal portions 57, 58, and 59, and of
the inverted tapering seal portions 57a, 58a, and S9a.
As described above, in the conventional cassette type
plasma torch, the cooling water supply conduit line 68a, the
cooling water discharge eonduit line 54, and the reactant gas
supply conduit line SS are sealed by the O-rings 63, 64, and 65 at
CA 02237668 1998-0~-14
the tapering seal portions 57, 58, 59, 57a, 58a, and 59a. At the
same time, they are electrically connected through the working
faces of these tapering seal portions. For this reason, when dust
or the like enters the aforementioned tapering seal portions, it is
5 possible that electrical contact failure occurs, and electric
discharge occurs among the seal portions to burn out the torch.
It often happens that the aforementioned O-rings are damaged by
the electric discharge, and that cooling water are mixed into
reactant gas so that the quality in welding or cutting is degraded.
In addition, each of grooves 66, 66a, 67, and 67a, which
communicates with each of the cooling water discharge conduit
line 54 and the reactant gas supply conduit line 55, is provided so
as to be laid on one another concentrically with respect to the arc
injection axis 20A. As a result, the outside dimension of the
entire torch body becomes large, and therefore the torch cannot
be used for a work which especially requires accessibility thereto.
In Japanese Patent Application Laid-open No. 2-6072, a
cartridge type plasma torch shown in Figs. 9 and 10 is disclosed.
A cartridge 71 is replaceable as an expendable article. An
electrode 72 and a torch nozzle 73, which are insulated by an
insulator 74, are replaced by an outside cartridge dismounting
device and cartridge mounting device by one operation, therefore
they are integrated in such a way as to be fixed to each other. A
ring-shaped groove 76 is included at a top portion or a tail portion
75 of the electrode 72, and a ball 78 and a rock ring 79 under the
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ball 78 are included at the inner end portion of a hole 77 in a torch
main body 70 side where the cartridge 71 is inserted. When the
cartridge 71 is inserted into the hole 77 from the front-end
portion of the torch main body 70, the ring-shaped groove 76
5 opposes the ball 78, and the rock ring 79 is pressed upward,
pressing the ball 78 into the ring-shaped groove 76, so that the
cartridge 71 is engagingly secured in the torch main body 70. By
carrying out the above operations in inverse order, the
aforementioned engagingly securing means is instantly released,
10 and the cartridge 71 is easily dismounted.
However, in the aforementioned cartridge type plasma
torch, the electrode 72, the insulator 74, and the torch nozzle 73
composing the cartridge 71 are designed to be replaceable by one
operation by an automatic replacing device or the like, therefore
15 they need to be completely and integrally constructed.
Accordingly, even when, for example, only the torch nozzle 73 is
desired to be replaced, the entire unit of the cartridge 71 must be
replaced, therefore the aforementioned cartridge type plasma
torch tends to be very uneconomical, and has a disadvantage of
20 higher running cost.
Further, in Japanese Utility Model Application
Publication No. 5-3860, a torch with an easy joint shown in Fig.
11 is disclosed. A torch main body 81 is attachable and
detachable to and from a torch support body 82, and a front-end
25 portion for connection 83 of the torch main body 81 is inserted in
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and connected to the inside of a main cylinder body 84 of the torch
support body 82. The torch main body 81 and the torch support
body 82 have gas introducing holes 85 and 86, which can
communicate with each other when connected, at respective axis
5 portions, and have water supply conduit lines 87 and 88, and
water discharge conduit lines 89 and 90 for cooling water of the
torch main body 81. The above water supply and water
discharge conduit lines of the torch main body 81 and the torch
support body 82 are designed to be communicated with each other
10 at the time of connection of the torch main body 81. Specifically,
a cooling water introducing hole 93 of the torch support body 82
and a water supply port 91 of the torch main body 81, and a
discharge hole 94 and a discharge port 92 of the torch main body
81, are respectively communicated with each other.
The cooling water introducing hole 93 of the torch
support body 82 is provided with a valve 95, and the valve 95 is
abutted to a valve seat 97, which is provided at the end portion of
the opening of the cooling water introducing hole 93, by the
compressive force of a compression spring 96, and closes the
20 cooling water introducing hole 93. A valve rocker arm 98 is
provided at the front end of the valve 95, and the front-end
portion of the valve rocker arm 98 is protruded inside the main
cylinder body 84 when the cooling water introducing hole 93 is
closed. When the torch main body 81 is connected to the torch
25 support body 82, the cooling water introducing hole 93 is opened
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by pressing the protruded valve rocker arm 98 by the front-end
portion for eonnection 83 of the toreh main body 81, and by
reversing the valve 95 against the compressive foree of the
eompression spring 96. When the toreh main body 81 is
5 separated from the toreh support body 82, the valve 95 eloses the
cooling water introducing hole 93 by the compressive force of the
compression spring 96, therefore cooling water is prevented from
dripping at the time of separation of the torch main body 81.
However, in the aforementioned torch with an easy joint,
10 it eannot be confirmed that the valve 95 is surely opened and
cooling water starts full cireulation when the toreh main body 81
and the torch support body 82 are connected. Consequently, if
the valve rocker arm 98, which opens and closes the valve 95, is
broken, or if impurities or the like in cooling water are
15 accumulated between the valve 9S and the valve seat 97, the torch
is used while insufficient eooling water flows therein. As a
result, there is a possibility that the torch body 81 is burnt down
due to insufficient cooling water.
Disclosure of the Invention
The present invention is made to eliminate the
aforementioned disadvantages of the conventional art, and its
object is to provide a cartridge type plasma toreh in which only
25 the expendables which need to be replaced can be easily replaced.
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The other objects are to prevent cooling water from dripping from
a torch main body when an expendable cartridge and the torch
main body are separated, to confirm secure connection when they
are connected, and to surely carry out the seal of cooling water
5 and operational gas, and the electric connection. Further,
another object is to improve the accessibility of the plasma torch
to a work piece.
The cartridge type plasma torch in aeeordanee with the
present invention is a plasma toreh for plasma welding or plasma
10 eutting, which ineludes an electrode, and a torch nozzle for
injeeting plasma arc from the electrode together with operational
gas received from the surroundings of the electrode, and is
characterized by including an expendable cartridge including the
electrode and / or the torch nozzle, and a torch main body which
15 has supply lines for supplying cooling water and operational gas
to the expendable cartridge, and which allows the expendable
cartridge to be mounted and / or dismounted from an end opposite
to an arc injection port when viewed in a longitudinal direction of
the torch. The aforementioned supply lines are desired to be
20 placed at the position where the axes thereof are displaced with
respeet to an are injection axis.
According to the structure, the expendable cartridge can
be easily replaced from the rear-end portion (an end opposite to
the arc injection port when viewed in a longitudinal direetion of
25 the torch) of the torch main body. The component parts of the
-
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expendable cartridge are constructed to be minimum replacement
units (an electrode, a torch nozzle, and the like) so as to be easily
dissembled and assembled at the time of replacement of only the
parts which need to be replaced, therefore after replacing the
5 parts which need to be replaced, the expendable cartridge can be
inserted into the torch main body. Consequently, running cost
can be reduced. Further, by displacing the axes of the supply
lines with respect to the arc injection axis, the supply lines of
cooling water and operational gas in the torch main body to the
10 electrode and the torch nozzle are axially displaced with respect
to the axes of the electrode for generating arc and the torch
nozzle, and can be formed in parallel therewith. Accordingly,
the outside width of the front-end portion of the torch can be
decreased, therefore the accessibility of the plasma torch to a
15 work piece is improved. As a result, the plasma torch is
applicable to a wider variety of work pieces.
A cartridge type plasma torch in accordance with the
present invention is a plasma torch for plasma welding or plasma
cutting, which includes an electrode, and a torch nozzle, and is
20 characterized by including an expendable cartridge including the
electrode and / or the torch nozzle, a torch main body which has
supply lines for supplying cooling water and operational gas to
the expendable cartridge, and which allows the expendable
cartridge to be mounted therein and / or dismounted therefrom,
25 and a cylinder type valve which is provided at the midpoint of the
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supply lines, and which opens the supply lines when the
expendable cartridge has been completely inserted into the torch
main body, and closes the supply lines when the expendable
cartridge is separated from the torch main body. The cylinder
5 type valve may move in a direction different from the direction in
which the cooling water flows when opening or closing the supply
line for supplying cooling water. Further, the cylinder type
valve may open or close both of the entrance to the expendable
cartridge from the supply line and the exit to the supply line from
10 the expendable cartridge at the same time.
According to the above structure, when the expendable
cartridge is separated from the torch main body, the cylinder type
valve closes the supply lines of the cooling water and operational
gas of the torch main body, therefore cooling water does not leak
15 into the inside of the torch, or does not adhere thereto, so that the
cooling water does not mix with the operational gas.
Consequently, degradation in quality of plasma welding or cutting
which is caused by the mixing can be prevented. Further, as the
result that the valve moves in a direction different from the
20 direction in which cooling water flows, the impurities mixed in
the cooling water do not adhere to the portion where the valve
seals the cooling water when it is closed, even if the impurities
may adhere to the cooling water supply conduit line.
Accordingly, the valve is returned to the position at which it is
25 completely closed, therefore the cooling water is surely stopped.
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Further, by opening or closing both of the entrance and the exit to
and from the expendable cartridge at the same time, the passage of
a medium such as cooling water or the like can be surely opened
or closed.
Further, an electric connection section between the
expendable cartridge and the torch main body can be connected
with screws. According to the above structure, even if dust or
the like enters the electric connection section between the
expendable cartridge and the torch main body, the expendable
10 cartridge is inserted into the torch main body by being screwed in,
therefore after eliminating the dust or the like by force, the
connection can be maintained on the working face of the screws so
that the connection is surely made.
It is preferable that any one of the expendable cartridge,
15 the torch body, and the cylinder type valve is provided with a
detecting means for detecting at least any one of the separation
and the completion of the insertion of the expendable cartridge
from and into the torch body.
According to the above structure, it is detected that the
20 expendable cartridge is surely inserted into the torch main body.
By controlling the operations of an outside plasma electric power
source, a cooling water pump, and so on based on the detecting
signal, malfunctions such as water leakage, electric discharge in
the torch, and so on, which are caused by poor incorporation can
25 be prevented. As the result, the torch can be surely operated
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after replacing the expendable cartridge, and the durability is
increased.
Further, it is preferable to provide an interlock means
which inputs a detecting signal from the detecting means, and
6 which stops the operation of at least any one of a power source
and a cooling water pump when the detecting signal shows the
separation, and actuates the power source and the cooling water
pump when the detecting signal shows the completion of the
insertion.
According to the above structure, when the expendable
cartridge is poorly connected or is not completely connected, the
power source or the cooling water pump can be stopped by the
interlock means. Accordingly, the torch is prevented form being
burnt, and an accident which gives an electric shock to an
15 operator, or the like can be prevented, so that there is an
advantage in durability and safety. In addition, the operation of
turning off the plasma power source, which is made by an operator
every time the expendable cartridge is replaced, becomes
unnecessary. Therefore the operational efficiency of the
20 replacement of expendables can be improved.
Brief Description of the Drawings
Fig. 1 is a longitudinal sectional view of a cartridge type
25 plasma torch in accordance with the present invention;
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Fig. 2 is a front view of the cartridge type plasma torch in
accordance with the present invention;
Fig. 3 is a longitudinal sectional view of an expendable
cartridge in accordance with the present invention;
Fig. 4 is a longitudinal sectional view of a torch main body
in accordance with the present invention;
Fig. S is a longitudinal sectional view of the cartridge type
plasma torch in which a second example of a cylinder rod in
accordance with the present invention is applied;
Fig. 6A is a section taken along a VI A - VI A line of Fig.
5, and is an explanatory view with a valve being opened;
Fig. 6B is an explanatory view with the valve in Fig. 6A
being closed;
Fig. 7 is a longitudinal sectional view of the conventional
15 cassette type plasma torch;
Fig. 8 A is a side view of a torch main body of the plasma
torch in Fig. 7;
Fig. 8B is a side view of a torch head of the plasma torch
in Fig. 7;
Fig. 9 is a longitudinal sectional view of the conventional
cartridge type plasma torch;
Fig. 10 is a sectional view of a replaceable cartridge
section of the plasma torch in Fig. 9; and
Fig. 11 is a longitudinal sectional view of the conventional
25 torch with an easy joint.
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Best Mode for Carrying out the Invention
A preferable embodiment of a cartridge plasma torch
5 according to the present invention will be described in details
with reference to the attached drawings.
Figs. 1 and 2 respectively show a longitudinal sectional
view and a front view of a front-end portion of a cartridge type
plasma torch 1 according to the present invention. The plasma
10 torch 1 consists of an expendable cartridge 2 including
expendables such as a torch nozzle 3, an electrode 4, and the like,
and a torch main body 30 having a hole into which the expendable
cartridge 2 is inserted. When divided broadly, the torch main
body 30 consists of an insertion section A provided with a hole
15 into which the expendable cartridge 2 is inserted, and which is
coaxial with an arc injection axis 20A, and a supply conduit line
section B having passages for supplying cooling water and
operational gas to the expendable cartridge 2. Incidentally, the
torch main body 30 is made of synthetic resin to be provided with
20 the property by which the torch main body 30 is electrically
insulated from the outside.
Figs. 3 and 4 are sectional views of the expendable
cartridge 2 and the torch main body 30. First, the expendable
cartridge 2 will be explained in detail based on Fig. 3. The
25 electrode 4, a guide cylinder 5, and the torch nozzle 3 are
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provided at the front-end portion of the expendable cartridge 2,
and are placed in a concentric form so that each axis matches to
the arc injection axis 20A.
The electrode 4 is to produce arc in the area between a
work piece and itself by an outside electric power source which is
not illustrated, and consists of an electrode stand 6, and an
electrode piece 7 which is attached at the center portion of the
foremost end of the electrode stand 6 by brazing, press-fitting, or
the like. The guide cylinder 5, which is made of material having
10 an insulating property, for example, ceramic, resin, or the like, is
inserted in the front-end side of the periphery portion of the
electrode stand 6, and the electrode 6 is supported by the torch
main body 30 with the guide cylinder 5 between them.
Further, the front-end part of the periphery portion of the
guide cylinder 5 is inserted into the rear portion of the torch
nozzle 3 having electrical conductivity, and the torch nozzle 3 is
electrically insulated from the electrode 4 by the guide cylinder 5.
As for the shape of the torch nozzle 3, the front portion has a
smaller diameter than the rear portion, and the middle portion has
a taper 3b so that the diameter from the rear portion to the front
portion is gradually made smaller. A flange portion 3a in a ring
form, which is protruded to the outside, is provided at the
periphery of the rear end portion of the torch nozzle 3, and when
the expendable cartridge 2 is inserted into the torch main body 30,
the position of the expendable cartridge 2 is determined by
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16
placing the front-end surface of this flange portion 3a against the
reference plane inside the torch main body 30.
A plasma gas chamber 38 (see Fig. 1), which is surrounded
by the inner face of the torch main body 30, is provided at the
5 periphery portion of the guide cylinder 5 supporting the electrode
4, and operational gas is supplied to the plasma gas chamber 38
from an operational gas supplying device on the outside through
an operational gas supply conduit line, which is not illustrated, in
the torch main body 30. The operational gas supply conduit line
10 is provided in the supply conduit line section B in the torch main
body 30. The plasma gas chamber 38 is communicated with a
space at the front-end side of the electrode piece 7 by a gas nozzle
19 provided at the front-end portion of the guide cylinder S to be
in a swirl form. The operational gas emits from the gas nozzle
15 19, turning towards the center of the space at the front-end side
of the electrode piece 7, and is designed to be injected from the
front-end portion of the torch nozzle 3.
An electrode cooling chamber 8 is provided at the central
portion of the electrode stand 6 of the electrode 4 along the axial
20 direction, and the electrode cooling chamber 8 is sealed by a seal
member (for example, an O-ring, hereinafter referred to as an
O-ring) 10 which is attached on the periphery portion of the
electrode stand 6. In addition, the front portion side of a
cooling water inlet conduit line 9 is inserted in the electrode
25 cooling chamber 8. Cooling water entering from a conduit line
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inside the cooling water inlet conduit line 9 cools the inside of the
electrode cooling chamber 8, and is discharged from a cooling
water discharge conduit line 17, which is described below, by way
of a passage surrounded by the outside of the cooling water inlet
5 conduit line 9 and the electrode cooling chamber 8.
A cartridge body 12 having electrical conductivity is
provided on the base end side of the expendable cartridge 2. The
electrode 4 is mounted in the front-end axis portion of the
cartridge body 12 with a screw 18, and a cylinder 11 having
10 insulating properties is connected to the periphery of the front-
end portion of the cartridge body 12 with the front-end portion of
the cartridge body 12 being inserted in the cylinder 11. The
aforementioned guide cylinder S is inserted between the front-end
portion of the cylinder 11 having insulating properties and the
15 front-end portion of the electrode 4. The connection of the
cartridge body 12 and the cylinder 11 can be made by bonding
them with, for example, an adhesive or the like, or by attaching
them with a screw.
As shown in the drawing, in this embodiment, the
20 connection of the cylinder 11 and the guide cylinder 5, and the
connection of the guide cylinder S and the torch nozzle 3 are
respectively made only by inserting the guide cylinder 5 into the
cylinder 11 and the torch nozzle 3, and they can be easily
dissembled. However, the entire body of the expendable
25 cartridge 2 may be integrally constructed by attaching the
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18
cylinder 11, the guide cylinder 5, and the torch nozzle 3 with
screws.
The rear portion of the aforementioned cooling water
inlet conduit line 9 is fixed and housed in the axis portion of the
5 cartridge body 12 by, for example, brazing. A cooling water
filling conduit line 16 and the cooling water discharge conduit
line 17 are provided at the rear portion of the cartridge body 12.
The cooling water filling conduit line 16 sends cooling water into
the conduit line inside the cooling water inlet conduit line 9 from
10 the torch main body 30 side, and the cooling water discharge
conduit line 17 discharges cooling water, which has cooled the
electrode 4, into the torch main body 30 side by way of the
passage surrounded by the outside of the cooling water inlet
conduit line 9 and the electrode cooling chamber 8.
Cooling water grooves 15 in a ring form are provided at
the portions where the periphery portion of the cartridge body 12
passes the inlet of the cooling water inlet conduit line 16 and the
outlet of the cooling water discharge conduit line 17. This
ring-shaped cooling water groove 15 is provided in order that the
20 cooling water is supplied without problems even if the
aforementioned cooling water conduit line in the expendable
cartridge 2 side and the cooling water conduit line in the torch
main body 30 side are displaced in the periphery direction, when
the expendable cartridge 2 is inserted into the torch main body 30.
25 Further, in order to seal each of the cooling water grooves 15,
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19
O-ring grooves are provided at the periphery portion of the
cartridge body 12, and O-rings 10 are inserted therein.
In addition, a cartridge fixing screw 13 is provided at the
rear portion of the periphery of the cartridge body 12, and a
5 handle 14 is attached at the rear-end portion of the cartridge body
12. The expendable cartridge 2, after inserted into the torch
main body 30, is manually screwed in by using the handle 14, and
fixed in the torch main body 30 with the cartridge fixing screw 13.
When the expendable cartridge 2 is to be dismounted from the
10 torch main body 30, it is suitable to perform the above operations
in inverse order.
Next, the torch main body 30 side will be explained in
detail. A ring-shaped cooling chamber 31 is provided inside the
front end of the insertion section A of the torch main body 30.
15 The ring-shaped cooling chamber 31 is a cooling water conduit
line which is provided around the middle portion of the periphery
of the torch nozzle 3 so as to be in a ring form when the
expendable cartridge 2 is inserted in the torch main body 30.
The aforementioned taper 3b at the middle portion of the
20 periphery of the torch nozzle 3 allows the cooling chamber 31 to
contain larger amount of cooling water, thereby increasing the
cooling efficacy. A nozzle cooling water inlet conduit line 32 in
the supply line section B of the torch main body 30 is connected
to the ring-shaped cooling chamber 31, and a cooling water return
25 conduit line 33 (see Fig. 2) in the supply line section B of the
-
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toreh main body 30 is also conneeted to the ring-shaped cooling
ehamber 31. The nozzle eooling water inlet conduit line 32 is
eommunicated with the eooling water diseharge eonduit line 17 at
the eartridge body 12 through a eylinder type valve whieh is
5 deseribed below, and the cooling water return conduit line 33 is
eonneeted to an outside eooling water pump, whieh is not
illustrated in the drawing, by way of a diseharge conduit line 47 in
the supply line section B. Incidentally, the discharge conduit
line 47 is provided in a synthetic resin packed bed 29.
An electrical supply sleeve 39 is provided behind the
ring-shaped cooling chamber 31 inside the torch main body 30.
The electrical supply sleeve 39 is almost in an cylindrical form,
and has a ring-shaped flange portion 39a whieh is protruded
inward (in an axial direetion) at the front-end portion. When the
15 expendable eartridge 2 is inserted into the toreh main body 30, the
position of the expendable eartridge 2 is determined by placing
the aforementioned flange portion 3a of the torch nozzle 3 of the
expendable cartridge 2 against the end faee of the flange portion
39a of the electrical supply sleeve 39. Electricity for pilot arc is
20 supplied to the torch nozzle 3 through the electrieal supply sleeve
39.
A shield gas eap 35 is provided at the front-end portion of
the insertion section A of the torch main body 30, and further, a
torch cap 34 is attached at the front-end periphery portion of the
26 shield gas cap 35. When the expendable cartridge 2 is being
CA 02237668 1998-OF,-14
inserted into the torch main body 30, the shield gas cap 35 is fitted
onto the front-end periphery of the torch nozzle 3. The axes of
the shield gas cap 35 and the torch cap 34 match to the axis of the
torch nozzle 3. The shield gas chamber 36 is provided between
5 the shield gas cap 35 and the torch cap 34, and a shield gas supply
conduit line, which is provided in the supply line section B and is
not illustrated in the drawing, is connected to the shield gas
chamber 36. The shield gas cap 35 is provided with a shield gas
nozzle 37 which is communicated with the shield gas chamber 36,
10 and shield gas emits from the shield gas nozzle 37.
A cooling water leakage protection cylinder 40 is
provided in the supply line section B of the torch main body 30.
A cylinder rod 41 of the cooling water leakage protection cylinder
40 is normally given a momentum towards the rear side of the
15 torch 1 by the elastic force of a spring 45. When the expendable
cartridge 2 is not inserted in the torch main body 30, the cylinder
rod 41 is moved to the rear side of the torch 1, and a lever 42 at
the rear portion of the cylinder rod 41 is protruded from the rear
end portion of the torch main body 30. When the expendable
20 cartridge 2 is inserted into and fixed in the torch main body 30,
the protruded lever 42 is pressed against the momentum, which is
given by the spring 45, by the reverse side (the side near the front
end of the torch 1) of the handle 14 of the expendable cartridge 2,
so that the entire body of the cylinder rod 41 is moved toward the
25 front side of the torch 1.
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Two of grooves 43 are provided in a ring form at
predetermined positions of the periphery of the cylinder rod 41,
the O-rings 10 are inserted in the periphery at the positions before
and after each of the two grooves 43. The torch main body 30 is
5 provided with a conveying conduit line (supply line) 46 for
sending cooling water from the cooling water pump, which is not
illustrated, to the cooling water filling conduit line 16 of the
expendable cartridge 2, and a nozzle cooling water conveying
conduit line (supply line) 48 for sending drainage from cooling
10 water discharge conduit line 17 of the expendable cartridge 2 to
the nozzle cooling water inlet conduit line 32. The cylinder rod
41 passes through the conveying conduit line 46 and the nozzle
cooling water conveying conduit line 48 in such a way as to be
perpendicular to each axis, so that the cylinder rod 41 opens and
15 closes the conveying conduit line 46 and the nozzle cooling water
conveying conduit line 48. Specifically, the aforementioned two
of the grooves 43 at the cylinder rod 41 are designed to match to
the positions of conveying conduit line 46 and the nozzle cooling
water conveying conduit line 48 when the expendable cartridge 2
20 is completely fixed in the torch main body 30. At this time, the
conveying conduit line 46 is communicate with the cooling water
filling conduit line 16, and the nozzle cooling water conveying
conduit line 48 is communicated with the cooling water discharge
conduit line 17 through the respective grooves 43. When the
25 expendable cartridge 2 is dismounted form the torch main body 30,
CA 02237668 1998-0~-14
23
the cylinder rod 41 is moved toward the rear side of the torch 1 by
the aforementioned momentum given by the spring 45, and the
positions of two of the grooves 43 are completely moved off the
positions of the conveying conduit line 46 and the nozzle cooling
5 water conveying conduit line 48 to close these cooling water
conduit lines.
A dctecting means for detecting the condition of the
insertion of the expendable cartridge 2 is provided at the front-
end portion (the end portion opposite to the lever 42) of the tube
10 of the cooling water leakage prevention cylinder 40. A signal
detected by the detecting means is outputted to an interlock
means 50. The interlock means 50 is connected to the
aforementioned power source and cooling water pump which are
not illustrated in the drawing, and gives a signal to stop and
15 restart the operations of the power source and the cooling water
pump. It may be suitable that the interlock means 50 is
connected to either one of the power source or the cooling water
pump. In the embodiment, as an example of the detecting means,
a micro switch 49 is provided, and a lever 49a of the micro switch
20 49 is protruded inward from the front-end portion of the tube of
the cooling water leakage prevention cylinder 40. When the
expendable cartridge 2 reaches the position where it is completely
fixed in the torch main boy 30, the cylinder rod 41 is pressed
forward, and the lever 49a is pressed by a front-end portion 44 of
25 the cylinder rod 41. When the expendable cartridge 2 is
CA 02237668 1998-0=,-14
24
dismounted, the cylinder rod 41 moves backward, and the lever
49a is released.
Next, the operation according to the above structure will
be explained. The expendable cartridge 2 is taken out of the
5 rear-end portion of the insertion section A of the torch main body
30 by loosening the cartridge fixing screw 13 by manually turning
the handle 14. The expendable cartridge 2 consists of the
electrode 4, the torch nozzle 3, the cartridge body 12 and so on.
These parts are simply inserted, or simply screwed in, therefore
10 each of them is easily disassembled and replaced. Accordingly,
the expendables of the torch 1 can be easily replaced in a short
time without using special tools or the like. In addition, it is
possible to only replace a part which is worn out and should be
replaced (for example, only the electrode 4, or only the torch
15 nozzle 3), so that there is a great advantage in running costs.
The O-ring 10 is inserted in each of the seal portions of
the cooling water and the operational gas in the torch main body
30 and the expendable cartridge 2, thereby surely sealing cooling
water and operational gas. Further, high current such as
20 welding current passes through an electric connection section
which is surely connected with the cartridge fixing screw 13 and
the screw 18. Therefore even if dust or the like should be mixed
into the electric connection section, electric current flows
through the working faces of the screws with stability. The
25 aforementioned O-rings 10 are inserted in the portions away from
CA 02237668 1998-0~-14
the electric connection section, therefore the O-rings 10 are not
damaged by electric discharge or the like occurring to the electric
connection section, and can surely seal cooling water and
operational gas. As the result, it is possible to prevent an
accident in which the torch 1 is burnt down by electric discharge
occurring to the electric connection section.
The expendable cartridge 2 is mounted and / or
dismounted from the rear end portion of the insertion section A of
the torch main body 30, specifically, the end face opposite to an
10 arc injection port 20 when viewed in a longitudinal direction of
the torch 1. As for the shape of the expendable cartridge 2, the
front-end portion is thinner, and the diameter gradually becomes
larger toward the rear side, in order that the expendable cartridge
2 is smoothly mounted and dismounted. The cooling water and
15 the operational gas supply conduit lines are placed so that the
axes are displaced with respect to the arc injection axis 20A,
specifically, the axes are displaced from the axis of the insertion
section A (the axis of the torch nozzle 3) of the torch main body
30 toward the inside of the supply line section B side.
Accordingly, the size of the portion near the arc injection port 20
of the torch main body 30 can be decreased, and an outside width
H of the insertion section A of the torch main body 30 can be
decreased. Consequently, the accessibility to a work piece is
improved, therefore the cartridge type plasma torch 1 of the
present invention is applicable to a work piece to which the
-
CA 02237668 1998-OS-14
26
conventional plasma torch is inapplicable due to the accessibility
thereto. As the result, an operation can be continued with the
torch 1 without replacing it with the other types of plasma torch,
therefore the time for the replacement is reduced, and the
5 operation efficiency is increased.
When the expendable cartridge 2 is completely inserted
and fixed in the torch main body 30, the cylinder rod 41 of the
cooling water leakage prevention cylinder 40, which is provided
at the cooling water inlet port and the cooling water outlet port of
10 the torch main body 30, is pressed toward the front side of the
torch 1 against the momentum which is given by the spring 45.
The positions of two of the grooves 43 which are provided at the
periphery of the cylinder rod 41 match to the positions of the
conveying conduit line 46 and the nozzle cooling water conveying
15 conduit line 48. At this time, the cooling water sent from the
outside cooling water pump is allowed to circulate inside the
electrode 4, the periphery portion of the torch nozzle 3 of the
expendable cartridge 2, and so on. Specifically, the cooling
water, which enters the electrode cooling chamber 8 by way of the
conveying conduit line 46, the groove 43, the cooling water filling
conduit line 16, and the inside of the cooling water inlet conduit
line 9, flows through the passage surrounded by the outer face of
the cooling water inlet conduit line 9 and the electrode cooling
chamber 8, and is guided to the ring-shaped cooling chamber 31
25 by way of the cooling water discharge conduit line 17, the groove
CA 02237668 1998-OF7-14
43, the nozzle cooling water conveying conduit line 48, and the
nozzle cooling water inlet conduit line 32. The cooling water is
returned to the cooling water pump from the ring-shaped cooling
chamber 31 by way of the cooling water return conduit line 33,
5 and the discharge channel 47. Thereby cooling the electrode 4
and the torch nozzle 3.
When the cylinder rod 41 reaches the front-end portion of
the cooling water leakage prevention cylinder 40 as described in
the above, the lever 49a of the micro switch 49 is pressed down,
10 and the micro switch 49 is actuated. Thus the micro switch 49
outputs a signal to the interlock means 50 to inform the interlock
means 50 that the expendable cartridge 2 is completely inserted
and fixed in the torch main body 30. By receiving the
aforementioned output, the interlock means 50 actuates the
15 power source and the cooling water pump.
When the expendable cartridge 2 is separated from the
torch main body 30, the cylinder rod 41 is pressed back to the rear
end side of the torch main body 30 by the momentum given by the
spring 45, and the positions of the grooves 43 and 43 are
20 displaced. Thereby closing the conveying conduit line 46 and
the nozzle cooling water conveying conduit line 48 to stop the
circulation of the cooling water. At this time, the lever 49a of
the micro switch 49 is returned to cancel the operating condition,
and the condition of the output contact signal of the micro switch
2.~ 49 is changed and is outputted to the interlock means 50,
CA 02237668 1998-0~-14
28
informing the interlock means 50 that the expendable cartridge 2
is separated from the torch main body 30. As a result, the
interlock mean 50 stops the operation of the power source and the
cooling water pump.
In this way, the ring-shaped grooves 43 of the cylinder rod
41 of the cooling water leakage prevention cylinder 40 function as
valves. The valves open at the time of completion of the
connection of the torch main body 30 and the expendable
cartridge 2, and close at the time of the separation, therefore
10 cooling water is prevented from leaking in or out of the torch 1.
Specifically, the cylinder type valve consists of the cylinder rod
41 of the cooling water leakage prevention cylinder 40, and the
grooves 43 and 43. In addition, the cylinder rod 41 moves in a
direction (in the above example, almost perpendicular direction)
15 which is different from the direction in which cooling water flows,
therefore even if impurities or the like in the cooling water adhere
to the cooling water grooves 43, the aforementioned impurities
never adhere to the portion which seals the cooling water.
Accordingly, when the expendable cartridge 2 is separated, the
20 cylinder rod 41 is returned to the position at which the valve is
surely closed by the momentum given by the spring 45. At this
time, the leakage of the cooling water is far more effectively
prevented by the O-rings 10 provided at the positions on the
periphery before and after the grooves 43 and the cooling water
25 groove 15 at the expendable cartridge 2 side. Accordingly, the
CA 02237668 1998-0~-14
29
cooling water is not mixed into operational gas, and therefore the
decline in the quality of welding or cutting, which is caused by the
cooling water, is prevented.
The micro switch 49 detects that the expendable cartridge
5 2 is completely incorporated in the torch main body 30, and based
on the detected signal, the interlock means SO actuates the power
source or the cooling water pump. Thereby enabling to prevent
a problem such as water leakage, or electric discharge inside the
torch 1 which is caused by the faulty incorporation. Further,
10 when the expendable cartridge 2 is dismounted from the torch
main body 30, it is detected with the micro switch 49, and by the
interlock means SO, the power source and the cooling water pump
are automatically stopped. Accordingly, when replacing the
expendables, an operator does not need to manually stop the
15 plasma power source and the cooling water pump, therefore the
operability is improved at the time of replacement.
Next, the second example of the cylinder rod 41, which
moves in a direction different from the direction in which cooling
water flows, will be explained with reference to Fig. S. Fig. S
shows the state of the insertion of the expendable cartridge 2.
The cylinder rod 41 is provided with a cooling water filling hole
21 for filling cooling water into the expendable cartridge 2, and a
cooling water discharge hole 22 for discharging the cooling water
from the expendable cartridge 2. These cooling water filling
hole 21 and the cooling water discharge hole 22 intersect the axis
CA 02237668 1998-0~-14
of the cylinder rod 41 at right angles. A guide groove 25 in a
helical form is provided at the periphery face of the lever 42 at the
rear end portion of the cylinder rod 41.
The lever 42 is covered with a rod cap 23, and a pin 24 is
provided at the inside of the rod cap 23 so as to be protruded
toward the lever 42 side. The pin 24 is engaged with the guide
groove 25 of the lever 42. The rod cap 23 is attached in such a
way as it moves in the longitudinal direction of the torch 1, but it
is not allowed to rotate. The rod cap 23 is normally given a
10 momentum in a rearward direction by the cylinder rod 41 given a
momentum by the spring 45, and when the expendable cartridge 2
is not inserted in the torch main body 30, the rod cap 23 is
protruded from the rear-end portion of the torch main body 30.
The cylinder rod 41 is fastened to a fastening member 40b at the
15 end portion opposite to the lever 42, and is rotatable inside the
supply line section B, but is not able to move in the longitudinal
direction of the torch 1.
In the above cylinder rod 41, when the rod cap 23 is
pressed forward at the time of the insertion of the expendable
20 cartridge 2 into the torch main body 30, the pin 24 is moved
forward along the guide groove 25 in a helical form. Following
the above, the cylinder rod 41 rotates about its axis, and the
cooling water filling hole 21 and the cooling water discharge hole
22 rotate. When the expendable cartridge 2 is completely
25 inserted in the torch main body 30, the direction of the cooling
CA 02237668 l998-0~-l4
31
water filling hole 21 matches to the direction of the hole of the
conveying conduit line 46 as Fig. 6A illustrates. Similarly, the
direction of the cooling water discharge hole 22 matches to the
direction of the nozzle cooling water conveying conduit line 48,
5 and as in Fig. 6A7 cooling water is circulated.
When the expendable cartridge 2 is separated form the
torch main body 30, the rod cap 23 is returned to the back of the
cylinder rod 41 by the momentum given by the spring 45, and the
pin 24 is moved in the direction opposite to the above along the
10 guide groove 25 so that the cylinder rod 41 rotates in the opposite
direction. As a result, as shown in Fig. 6B, the direction of the
cooling water filling hole 21 is completely displaced from the
direction of the hole of the conveying conduit line 46, and the
same thing happens to the cooling water conveying conduit line
15 48, so that the cooling water is stopped. Accordingly, in this
example, the cylinder type valve consists of the cylinder rod 41 of
the cooling water leakage prevention cylinder 40, the cooling
water filling hole 21, and the cooling water discharge hole 22.
In this way, in the above example, the cylinder 41 also
20 moves in a direction different from the direction in which the
cooling water flows. Specifically, in the second example, the
cylinder rod 41 rotates about its axis. Accordingly, similarly to
the above description, impurities in the cooling water do not
adhere to the outer surface 41a of the cylinder rod 41, the inner
25 face of the cylinder tube side, and the cooling water seal surface
CA 02237668 1998-OF,-14
32
other than the cooling water filling hole 21 and the cooling water
discharge hole 22. As a result, when the expendable cartridge 2
is separated, the cylinder rod 41 is rotated by the momentum given
by the spring 45 up to the position where the cooling water filling
~ hole 21 and the cooling water discharge hole 22 are surely closed.
In the present embodiment, the micro switch 49 is used as
an example of a detecting means for detecting the condition of the
insertion of the expendable cartridge 2, but the detecting means is
not limited to the micro switch 49, and a proximity switch or the
10 like can be used. The location of the detecting means is not
limited to the front-end portion of the tube of the cooling water
leakage prevention cylinder 40 as in the present embodiment, but
it can be placed at the middle portion of the tube or the like.
Further, the above detecting means can be placed at the cylinder
15 rod 41 side or the expendable cartridge 2 side when placing it in
the position other than the torch main body 30.
In the above embodiment, the examples are explained, in
which the cooling water supply conduit line is opened and closed
by the cylinder type valve, but the supply conduit line of
20 operational gas can be also constructed so as to be opened and
closed by the cylinder type valve similar to the above. In this
case, the operation and the effects are obtained similarly to the
above .
Industrial Availability
CA 02237668 1998-0~-14
The present invention is useful as a cartridge type plasrna
torch in which only the expendables necessary to be replaced can
be easily replaced, cooling water and operational gas are securely
5 sealed when expendables are replaced, while the electrical
connection is surely made, and in which the accessibility to a work
piece is improved during the operation.
