[0001] This invention relates to a method and apparatus for filling and discharging a molten
filling material of low melting point into and out of a workpiece, for example a tube
which is to be bent.
[0002] When it is required to bend a workpiece in the form of a tube, a filling material
of low melting point is introduced into the straight tubular workpiece to enable it
to be bent with accuracy. However, conventionally the steps of filling the filling
material into the straight workpiece, bending the workpiece and then heating the same
to melt and discharge the filling material have been carried out at different locations.
[0003] Consequently, the filling material, once melted and discharged, has to be kept in
a heated reservoir and then delivered to the straight workpiece by means of a pump.
[0004] Also, generally, the straight workpiece is supported by a carrier which is provided
with a nozzle adapted to engage with the upper end portion of the workpiece for filling
the filling material therein to, whilst a sealing member engages with the lower end
of the workpiece.
[0005] Thus, since each of the steps of filling, and melting and discharging the filling
material, are carried out at different places, making it necessary to have a heated
reservoir for the discharged molten filling material, a large working space is needed,
together with energy for keeping hot a large quantity of filling material. Further,
it takes a comparatively long time to finish a series of workpieces. It is therefore
desired not only to decrease the working space, but also to improve the working efficiency,
by eliminating the heated reservoir for the discharged filling material.
[0006] Still further, since the aforementioned nozzle and sealing member can only be used
for one specification of the workpiece, relative to its length and inner and outer
diameters, it becomes necessary to reassemble the carrier whenever the specification
of the workpiece is changed, and this is clearly inconvenient. It is therefore desired
to provide for such changes in the specification of the workpiece in more efficient
manner.
[0007] Viewed from one aspect the present invention provides a method of treating a tubular
workpiece by working upon it while it contains a filling material, comprising the
steps of:
introducing the molten filling material into an unworked tubular workpiece;
then working on the workpiece to bring it to a worked condition; and
then heating the workpiece to melt and discharge the filling material;
characterised in that there is provided a single filling and discharging furnace
having in the lower part thereof a filling furnace for filling the filling material
into an unworked tubular workpiece, and in the upper part thereof a discharging furnace,
the filling material being melted and then discharged from a worked workpiece in the
discharging furnace, and the molten discharged filling material being gathered in
a reservoir in the discharging furnace and thence introduced into an unworked workpiece
disposed in the filling furnace.
[0008] Viewed from another aspect the invention provides a filling and discharging furnace
for carrying out the method set forth above, comprising
a discharging furnace for melting and discharging filling material of low melting
point from a worked tubular workpiece;
a filling furnace for introducing the filling material into an unworked tubular
workpiece;
the discharging furnace being arranged above the filling furnace;
hot air circulating means communicating with both the discharging furnace and the
filling furnace and arranged to feed the majority of the hot air flow into the discharging
furnace and a remaining portion thereof into the filling furnace; and
a reservoir in the discharging furnace for collecting the molten filling material
and having an outlet valve for releasing the collected filling material into the filling
furnace.
[0009] Viewed from a further aspect the invention provides a carrier for a workpiece which
is to be worked upon whilst filled with a material, comprising:
a carrier body;
a filling deck disposed at the upper part of the carrier body;
a sealing deck disposed at the lower part of the carrier body; and
a lifting deck arranged to move up and down whilst supporting an unworked tubular
workpiece;
the filling deck comprising an upwardly open receptacle for holding molten filling
material and provided with a nozzle which extends downwardly from a through bore formed
in the bottom of the receptacle and which has an inner diameter substantially equal
to the outer diameter of the workpiece, the upper end of which is adapted to engage
with the nozzle when moved upwardly; and
the sealing deck being arranged to move up and down and having a seal member which
has an outer diameter substantially equal to the inner diameter of the workpiece,
the lower portion of which is adapted to engage with the seal member when the sealing
deck is moved upwardly.
[0010] Since, according to the present invention, there is provided a filling and discharging
furnace with a discharging furnace and a filling furnace disposed at the upper and
lower parts thereof respectively, it is possible at the same time to fill a filling
material in the filling furnace and to melt and discharge it in the discharging furnace,
and as a result a heated reservoir for the discharged molten filling material is no
longer necessary. Thus, it is not only possible to reduce the working space and save
the heat in the filling material, but also to improve the working efficiency by carrying
out a plurality of operations in one place. It is also possible to recycle the filling
material in a minimum quantity.
[0011] If, as is preferred, the filling furnace is heated by utilizing a part of the hot
air which is mainly sent to the discharging furnace, it is also possible to save energy
and simplify the structure of the heat keeping equipment within the filling and discharging
furnace.
[0012] Also, when as is preferred the opening and closing operations of a valve of a hot
air exhaust duct are linked with those of doors respectively provided for the discharging
furnace and the filling furnace, for the workpieces to be moved in and out, hot air
may be prevented from escaping through the doors when they are open.
[0013] If, as is preferred, the bottom of the discharging furnace is formed with a sloping
surface, it is also possible to effect quick and sure release of the filling material
into the filling furnace.
[0014] On the other hand, when a filling carrier for filling the filling material into a
workpiece is situated within the filling furnace and under a valve formed at the bottom
of a reservoir in the discharging furnace, it is possible efficiently to release the
filling material into such a filling carrier situated in the filling furnace.
[0015] Further, if as is preferred a plurality of workpiece carriers are arranged to be
accommodated in both the filling furnace and the discharging furnace at the same time,
the working efficiency is further improved.
[0016] A workpiece carrier according to the present invention is preferably divided into
three parts, comprising a carrier body, a filling deck and a sealing deck, the carrier
body being provided with a lifting deck adapted to move up and down while supporting
a workpiece thereon, the filling deck being provided with a nozzle, and the sealing
deck being provided with a seal member and being arranged to move up and down. When
it is desired to change the specification of the workpiece, it is not necessary to
change the carrier body, but only to change the nozzle and the seal member. Since
the number of parts to be changed can thus be kept as low as possible, costs are reduced,
and since it is no longer necessary to keep different kinds of carriers, less space
is needed.
[0017] If, as is preferred, a number of workpieces are supported on such a carrier and also
a plurality of nozzles and seal members are provided, arranged to correspond to these
workpieces, it is possible to fill the filling material into a number of workpieces
at the same time and thus notably improve the working efficiency.
[0018] Also, when as is preferred the workpieces are detachably secured at their peripheries
to the sides of the carrier by resilient engaging members, their manner of attachment
or detachment becomes simple and reliable.
[0019] Further, when as is preferred the lifting deck is elevated by the elevation of the
sealing deck, which is also adapted to be elevated by a lifter provided separately
from the carrier body, so that the upper end of the workpiece may be connected to
the nozzle and the opening at the lower end of the workpiece may be sealed by the
seal member, it is not only possible to make the construction of the carrier simple,
but also to carry out both the processes of connecting and sealing the workpiece at
the same time, and thus reduce the number of the steps involved in filling.
[0020] In this case, if as is preferred the nozzle and the seal member are designed to be
replaceable in response to changes in the specification of the workpiece, and the
filling deck is held relative to the carrier body by a removable support, it is possible
to cope with such changes of specification of the workpiece more flexibly.
[0021] Further, if the sealing deck is designed to be held by a removable support relative
to the lower portion of the lifting deck when lifted, it is possible to make the manner
of positioning of the lifting deck simple and reliable.
[0022] Still further, if the filling deck is provided with a detachably mounted guide pin
which is adapted to engage with the inside of the upper end portion of the workpiece
with a certain clearance formed therebetween, and if the guide pin is situated concentrically
with the nozzle, it is possible to make the manner of positioning of the workpiece
and the filling deck simple and to cope with changes in the specification of the workpiece
more easily.
[0023] An embodiment of the invention will now be described by way of example and with reference
to the accompanying drawings, in which:-
Fig. 1 is a view showing diagrammatically a bending process according to a preferred
embodiment of the present invention;
Fig. 2 is a sectional side elevation of apparatus for carrying out the process of
Fig. 1;
Fig. 3 is a cross-sectional view showing basic parts of the apparatus;
Fig. 4 is a cross-sectional view showing basic parts of a workpiece filling carrier
of the apparatus;
Fig. 5 is a plan view of the filling carrier;
Fig. 6 is a sectional side elevation of the filling carrier;
Fig. 7 is a cross-sectional view taken along line C-C of Fig. 4;
Fig. 8 is an enlarged sectional view taken along line D-D of Fig. 6;
Fig. 9 is a partially enlarged sectional view showing further parts of the apparatus;
Fig. 10 is a partially enlarged sectional view showing other parts of the apparatus;
Fig. 11 is a sectional side elevation of a workpiece discharging carrier of the apparatus;
and
Fig. 12 is a front view of the discharging carrier.
[0024] Referring to the drawings, Fig. 1 is a view which diagrammatically illustrates a
bending process of an exhaust pipe for a motorcycle.
[0025] First, a straight tubular workpiece 1 in the form of a double tube comprising inner
and outer pipes is formed by welding and is introduced into a filling furnace 3 which
forms the lower part of a filling and discharging furnace 2. At the same time, a tubular
workpiece 6 which has already been bent is introduced into a discharging furnace 4
which forms the upper part of the furnace.
[0026] Then, when the discharging furnace 4 has been heated above the melting point of a
filling material, molten filling material discharged from the bent tubular workpiece
6 is collected in a reservoir 5 formed in a floor 7 of the discharging furnace 4.
Filling material from the reservoir is then used to fill the space between the inner
and outer pipes of the straight tubular workpiece 1 located in the lower filling furnace
3.
[0027] Following that, the bent tubular workpiece 6, emptied of filling material, is moved
out of the discharging furnace 4 to a succeeding process station. Also, the straight
tubular workpiece 1 filled with the filling material is taken out of the filling furnace
3 to undergo the next bending process. Since the workpiece 1 is filled with the filling
material, it is possible to accurately carry out bending operations on the inner and
outer pipes so as to form a bent tubular workpiece 6. The bent tubular workpiece 6
is then introduced into the discharging furnace 4, where the filling material is melted
and discharged as described above.
[0028] Fig. 2 is a sectional side elevation schematically showing the filling and discharging
furnace 2, while Fig. 3 is a cross-sectional view showing only a portion of the furnace
2 and a carrier therein, as seen from a front of the furnace (arrow A in Fig. 2).
The inside of the furnace 2 is divided into upper and lower sections by the floor
7 of the discharging furnace 4, which also serves as a partition wall. Two reservoirs
5 (Fig. 3) are formed to extend in opposite directions from the central region of
the floor 7, the bottoms 8 of which slope downwardly toward the interior of the filling
furnace 3. A valve 9 is provided at the lowest point of each reservoir, operable from
outside by a suitable means to open and close it.
[0029] Discharging carriers 10 for carrying the bent tubular workpieces 6 are located on
the floor 7 of the discharging furnace 4, while filling carriers 12 for carrying the
straight tubular workpieces 1 are located on a floor 11 of the filling furnace 3.
Two such carriers are provided, one on each side, in each of the furnaces 3 and 4.
A wall 13 stands up from the floor 11 of the filling furnace 3, with its top at the
same level as the floor 7 of the discharging furnace 4.
[0030] A doorway of the discharging furnace 4 which faces the wall 13 is opened and closed
by a door 14 which is movable up and down, while a doorway of the filling furnace
3 is situated on the opposite side and is opened and closed by a double-leafed hinged
door 15.
[0031] Hot air circulating means, including a main duct 16, an axial-flow fan 17 and a duct
heater 18, is provided in a top portion of the filling and discharging furnace 2,
the axial-flow fan 17 being driven by a motor 19. The main duct 16 communicates with
a suction duct 20, an exhaust duct 21, and a supply duct 22.
[0032] The suction duct 20 opens in the upper region of the discharging furnace 4, while
the exhaust duct 21 opens to the atmosphere to discharge the hot air fed from the
axial-flow fan 17, being opened and closed by a valve 23. The opening and closing
operations of the valve 23 are linked to those of the doors 14 and 15. The valve 23
is arranged to quickly decrease the temperature, especially within the discharging
furnace 4, by opening the exhaust duct 21 to atmosphere after the filling and discharging
of the filling material but before the doors 14 and 15 are opened, so that hot air
does not blow out of the doors. The valve 23 is arranged to be closed while the doors
14 and 15 are closed, during the operations to fill and discharge the filling material.
[0033] The supply duct 22 extends vertically within the filling and discharging furnace
2 and is arranged to supply a larger proportion of the hot air flow into the discharging
furnace 4, through a supply port 24 opening into the lower proportion of the furnace
4, and the remaining portion thereof into the filling furnace 3 through a supply port
25 opening into the upper part of the filling furnace.
[0034] The inside of the discharging furnace 4 is heated by the hot air fed through the
supply port 24 to about 1500°C, which is higher than the melting point of the filling
material, while the inside of the filling furnace 3 is kept at a temperature of about
600°C. The hot air flow entering the discharging furnace 4 through the supply port
24 heats the bent tubular workpieces 6 mounted on the discharging carrier 10 and then
exits through the suction duct 20, while the hot air flow entering into the filling
furnace 3 through the supply port 25 also passes to the suction duct 20 through a
communicating port 26 formed in the floor 7 of the discharging furnace 4. The hot
air is then heated again by the duct heater 18 before being recirculated through the
furnace 2.
[0035] One of the workpiece filling carriers 12 will now be described in more detail with
reference to Figs. 4 to 10.
[0036] Fig. 4 is a cross-sectional view showing the filling carrier 12 from the front thereof
(arrow A in Fig. 2) in the condition of carrying a number of straight tubular workpieces
1. The filling carrier is divided into three parts, namely a filling deck 30, a carrier
body 31 and a sealing deck 32. The sealing deck 32 is arranged to be moved up and
down by lifting means such as a hydraulic device (not shown).
[0037] Fig. 5 is a plan view showing the filling carrier before it is loaded with workpieces.
Fig. 6 is a side elevation thereof showing, on the left, the condition of the carrier
before receiving the straight tubular workpieces 1 and, on the right, a cross-section
after receiving the same. Figs. 9 and 10 are enlarged cross-sectional views showing
the upper and lower end portions of the straight tubular works 1 in the condition
as shown on the right of Fig. 6.
[0038] As is apparent from these Figures, the filling carrier body 31 is loaded with two
rows of straight tubular workpieces 1, the rows extending in the front to rear direction.
The workpieces are supported by detachably engaging their middle portions in substantially
C-shaped support clips 34, the circumference of which is partially cut away as shown
in Fig. 7.
[0039] The support clips 34 are arranged in two rows, supported by a central cross member
35 which extends from front to rear in the central region of the carrier body 31.
The ends of the cross member 35 are secured to reinforcement members 37 extending
between frame members 36.
[0040] The carrier body 31 is provided at its lower part with a lifting deck 38 arranged
to support the lower ends of the straight tubular workpieces 1. The lifting deck 38
is supported to move up and down by guides located in the four corners between the
frame members 36. When the lifting deck 38 has been moved up, together with the sealing
deck 32, by a lifter (not shown), it is supported against moving down by inserting
supporting pipes 40 under the sealing deck 32 (see Figs. 5 and 6), the ends of the
pipes 40 extending through brackets 42 mounted on frame members 41.
[0041] As is apparent from Fig. 6, the filling deck 30 extends downwardly between upper
frame members 43 and forms an upwardly open receptacle 44, provided at its upper periphery
with a flange 45. The flange portion 45 is mounted on the upper surfaces of the frame
members 43, and the filling deck 30 is supported by pipes 46, similar to the pipes
40, which pass through holes 48 (Fig. 4) formed in upstanding edge portions 47 of
frame members 43.
[0042] Inside the receptacle 44 guide pins 51 are detachably secured by bolts 49 to brackets
50 at positions corresponding to each straight tubular workpiece 1. The lower end
of each guide pin 51 extends downwardly through the bottom of the receptacle 44 and
is there enclosed by a pipe-shaped nozzle 52 secured to the receptacle 44.
[0043] As is apparent from Fig. 9, the inner diameter of the nozzle 52 is slightly more
than the outer diameter of the upper end portion of the outer pipe 53 of the straight
tubular workpiece 1, while the outer diameter of the guide pin 51 is slightly less
than the inner diameter of the upper end portion of the inner pipe 54, which extends
beyond the outer pipe 53. Accordingly, when the lifting deck 38 is moved upwards,
the upper end portion of the workpiece 1 has its outer pipe 53 and inner pipe 54 engaged
closely between the guide pin 51 and the nozzle 52.
[0044] As is apparent from Fig. 8, the upper end region of the inner pipe 54 is non-circular
in cross-section, whereby a clearance 55 is formed between the outer pipe 53 and the
inner pipe 54. Also, as is apparent from Fig. 9, a through bore 57 is formed in the
bottom 56 of the receptacle 44, and the space between the outer pipe 53 and the inner
pipe 54 communicates with the inside of the receptacle 44 through the bore 57, the
nozzle 52 and the clearance 55, as shown in Fig. 9. The bore 57 allows the guide pin
51 to pass therethrough, having a larger diameter than the pin. The nozzle 52 is detachably
secured by bolts 58 to the bottom 56 of the receptacle 44.
[0045] On the other hand, the lower end region of the straight tubular workpiece 1 is, as
shown in Fig. 10, arranged such that the outer pipe 53 and the inner pipe 54 are in
close contact with each other. A seal member 60 made of heat-resistant elastic material
such as a silicone rubber closely engages the inside the inner pipe 54 so that it
can seal a weep hole formed in the inner pipe 54. A through bore 62 is formed in an
upper surface panel 61 of the lifting deck 38, in which a ring 63 is secured. A stopper
ring 64 engages with the ring 63 and the lower end of the workpiece 1.
[0046] The seal member 60 is detachably secured at its base 65 to the sealing deck 32, through
bolts 66. As is apparent from Figs. 4 and 6, the sealing deck 32 is provided, at the
center region of both of its ends, with upwardly protruding positioning pins 67 adapted
to engage with holes 68 (Fig. 6) formed in the lifting deck 38, when the sealing deck
32 is moved upwardly.
[0047] The carrier body 31 is arranged to carry different kinds of straight tubular workpieces
1 with different specifications, such as in their inner and outer diameters and their
lengths. When the specifications of the workpieces are changed, it is possible to
cope with such changes by simply changing the nozzle 52 and the seal member 60, and
also the guide pin 51 if necessary.
[0048] Figs. 11 and 12 respectively show a sectional side elevation and a front view of
a discharging carrier 10. As shown in Fig. 11, a pair of intermediate frame members
71 are arranged between front and rear frame members 70, and supporting plates 72
and 73 are mounted on the frame members 71. Plates 72 and 73 are provided with supporting
clips 74 and 75 similar to the supporting clips 34 (Fig.7).
[0049] The top end of the supporting plate 72 extends upwardly, while the top end of the
supporting plate 73 extends substantially horizontally. As a result, the supporting
plates 72 and 73 are at about 90° to each other. Consequently, when a bent tubular
workpiece 6 is engaged in the supporting clips 74 and 75, one end region of the workpiece
6, where its inner and outer pipes are sealed up, is supported substantially horizontally
by clip 74, while the other end region where the inner and outer pipes are open (i.e.
the end into which the filling material was introduced), is supported to face downwardly,
as shown.
[0050] The bent tubular workpieces 6, supported in such manner, are arranged in two rows
facing each other, as shown in Fig. 12.
[0051] Reference numeral 76 indicates an auxiliary bracket for use in a case where the shape
of the bent tubular workpiece 6 is different from what is shown, when another supporting
plate 73 formed in a suitable shape may be attached thereto. Reference numeral 77
indicates a pin for attachment of a lifting chain when it is desired to lift the discharging
carrier 10 for relocation.
[0052] The operation of the illustrated embodiment will now be described. Referring to Figs.
2 and 3, the discharging carrier 10 is located on the floor 7 of the discharging furnace
4, while the filling carrier 12 is located on the floor 11 of the filling furnace
3. In such a condition, when the doors 14 and 15 are closed and hot air is fed into
the filling and discharging furnace 2 by the hot air circulating means, the inside
of the discharging furnace 4 is heated to approximately 1500°C, which is higher than
the melting point of the filling material, so that the filling material in the bent
tubular workpieces 6 on the discharging carrier 10 melts and is discharged into the
reservoir 5, because the open ends of the bent tubular workpieces 6 face downwardly,
as seen in Fig. 11. At the same time, the inside of the filling furnace 3 is kept
at a temperature of about 600°C.
[0053] Next, when the valve 9 is opened, the filling material collected in the reservoir
5 is discharged toward the filling carrier 12 situated in the lower filling furnace
3 and is there received in the receptacle 44 of the filling deck 30. The filling material
then passes through the through bore 57, the upper end portion of each straight tubular
workpiece 1, and the clearance 55 (Fig. 8), to be filled into the space between the
outer pipe 53 and the inner pipe 54 of each workpiece 1.
[0054] In a case where the specification, such as the length or the inner or outer diameter,
of the straight tubular workpiece 1 is changed, it is only necessary to change the
nozzle 52 and the seal member 60, and possibly also the guide pin 51, without changing
the carrier body 31. Accordingly, the necessary changes to the filling carrier 12
resulting from such a change in specification of the workpiece 1 is minimised, and
it is therefore no longer necessary to maintain many kinds of filling carriers each
of which has been exclusively prepared for a particular specification of the straight
tubular workpiece 1. It is thus possible to save the cost of such carriers and the
space for storing them.
[0055] Since one carrier 10 or 12 is adapted to carry many workpieces 1, and two each of
the carriers 10 and 12 are put into the filling and discharging furnace 2 at a time,
it is possible to greatly improve the working efficiency.
[0056] Since the carrier body is not provided with a seal member, then even if hot straight
tubular workpieces are placed thereon immediately after welding there is no damage
of a seal member being damaged by heat.
[0057] Moreover, since one filling and discharging furnace 2 has a filling furnace 3 and
a discharging furnace 4 arranged in the lower and upper parts thereof, it is possible
to carry out the filling of the filling material and the melting and discharging thereof
at the same time, thus reducing the working space considerably and improving the working
efficiency. Also, since the conventional heat keeping reservoir for discharged filling
material is not needed any more, it is not only possible to save the heat of the discharged
filling material, but also to make the construction of the equipment simpler and more
compact, and to increase the degree of freedom in the equipment layout.
[0058] Also, since the hot air is circulated within the discharging furnace 4 by the hot
air circulating apparatus, it is possible to utilize the heat effectively and to accelerate
the increase in the temperature during heating. Further, since the interior of the
filling furnace 3 is also arranged to be kept warm by utilizing a proportion of the
hot air fed to the discharging furnace 4, heat energy is saved.
[0059] The present invention is of course not limited to the above embodiments, but may
be modified and changed in many ways. For example, the workpiece can be a multiple
pipe of three or more layers, or indeed a single walled pipe.
1. A method of treating a tubular workpiece by working upon it while it contains a filling
material, comprising the steps of:
introducing the molten filling material into an unworked tubular workpiece (1);
then working on the workpiece to bring it to a worked condition (6); and
then heating the workpiece to melt and discharge the filling material;
characterised in that there is provided a single filling and discharging furnace
(2) having in the lower part thereof a filling furnace (4) for filling the filling
material into an unworked tubular workpiece, and in the upper part thereof a discharging
furnace (3), the filling material being melted and then discharged from a worked workpiece
in the discharging furnace, and the molten discharged filling material being gathered
in a reservoir (5) in the discharging furnace and thence introduced into an unworked
workpiece disposed in the filling furnace.
2. A filling and discharging furnace for use in carrying out the method claimed in claim
1, comprising:
a discharging furnace (4) for melting and discharging filling material of low melting
point from a worked tubular workpiece;
a filling furnace (3) for introducing the filling material into an unworked tubular
workpiece;
the discharging furnace being arranged above the filling furnace;
hot air circulating means (16) communicating with both the discharging furnace
and the filling furnace and arranged to feed the majority of the hot air flow into
the discharging furnace and a remaining portion thereof into the filling furnace;
and
a reservoir (5) in the discharging furnace for collecting the molten filling material
and having an outlet valve (9) for releasing the collected filling material into the
filling furnace.
3. Apparatus according to claim 2, wherein the hot air circulating means comprises a
valved exhaust duct (21) for releasing the hot air in the discharging furnace to the
exterior, a first supply port (24) for supplying the hot air flow into the discharging
furnace (4), and a second supply port (25) for supplying the hot air flow into the
filling furnace (3), and wherein the opening and closing of the valve (23) of the
exhaust duct are linked with the operation of doors (14,15) respectively provided
in the discharging furnace and the filling furnace for movement of the workpieces
in and out.
4. Apparatus according to claim 2 or 3, wherein the said reservoir (5) has an sloping
bottom surface (8) which protrudes downwardly towards the filling furnace (3).
5. Apparatus according to any of claims 2 to 4, wherein a filling carrier (12) is disposed
in the filling furnace (3) below the outlet valve (9) of the said reservoir (5).
6. Apparatus according to any of claims 2 to 5, wherein a plurality of workpiece carriers
(10,12) are arranged to be accommodated in both the filling furnace (3) and the discharging
furnace (4) at the same time.
7. A carrier for a workpiece (1) which is to be worked upon while containing a filling
material, comprising:
a carrier body (31);
a filling deck (30) disposed at the upper part of the carrier body;
a sealing deck (32) disposed at the lower part of the carrier body; and
a lifting deck (38) arranged to move up and down while supporting an unworked tubular
workpiece (1);
the filling deck comprising an upwardly open receptacle (44) for holding molten
filling material and provided with a nozzle (52) which extends downwardly from a through
bore formed in the bottom of the receptacle and which has an inner diameter slightly
greater than the outer diameter of the workpiece, the upper end of which is adapted
to engage with the nozzle when moved upwardly; and
the sealing deck being arranged to move up and down and having a seal member (60)
which has an outer diameter slightly less than the inner diameter of the workpiece,
the lower portion of which is adapted to engage with the seal member when the sealing
deck is moved upwardly.
8. A carrier of according to claim 7, wherein the carrier body (31) is adapted to support
a plurality of workpieces, the said filling deck (30) being provided with a plurality
of said nozzles (52) and the said sealing deck being provided with a plurality of
said seal members (60), the nozzles and seal members being arranged to cooperate with
a said plurality of workpieces.
9. A carrier according to claim 8, including resilient engaging clips (34) for supporting
the workpieces (1).
10. A carrier according to any of claims 7 to 9, wherein the said lifting deck is arranged
to be lifted as the said sealing deck (32) is lifted, so as to allow the upper end
of a workpiece to be connected to a said nozzle (52) and the opening of the lower
end thereof to be sealed by a said sealing member (60).
11. A carrier according to any of claims 7 to 10, wherein the said nozzle (52) and the
said sealing member (60) are replaceable in response to a change in the specification
of the workpiece.
12. A carrier of according to any of claims 7 to 11, wherein the said sealing deck is
arranged to be lifted by a lifter separate from the carrier body (31).
13. A carrier according to any of claims 7 to 12, wherein the said sealing deck (32) is
arranged to be held by support means (40) against the lower part of the lifting deck
(38) when lifted.
14. A carrier according to any of claims 7 to 13, wherein the filling deck (30) is arranged
to be detachably held relative to the carrier body (31) by support means (46).
15. A carrier according to any of claims 7 to 14, wherein the filling deck (30) is provided
with a detachably mounted guide pin (51) which is adapted to engage with the inside
of the upper end of a workpiece with a clearance formed therebetween, the guide pin
being concentric with the said nozzle (52).