Welding device with movable and immovable electrodes for welding tubes

A portable device for welding a heat weldable tube has a main body case, a first electrode supported on an end part of the main body case, a movable member arranged opposite to the end part of the main body case, a second electrode arranged on the movable member substantially opposite to the first electrode, a manipulation member for displacing the movable member forwardly and rearwardly with respect to the end part of the main body case, a first elastic member returning the manipulation member to a predetermined position when the manipulation member has been opened, and a second elastic member providing elasticity in a direction of movement of the movable member when the movable member moves toward the end part of the main body case by the manipulation member.

The present invention relates to the improvement of a simple type welding 
device for tube in which middle part of a tube made of a heat weldable 
material such as vinyl, a synthetic resin, etc. is pressed, and is welded 
so that the internal passage of the tube is closed, and sure and 
stabilized welding is made possible by carrying out the welding of the 
tube with a uniform force. 
For example, in the case when blood collecting procedure is carried out in 
a blood donating car or the like, a blood collecting bag constituted of a 
soft quality plastic material such as vinyl chloride and the like is used. 
A vinyl tube made of the same material as that of the blood collecting bag 
is connected to this blood collecting bag, and a blood collecting needle 
is connected to the tip of the tube. 
In the case of collecting blood, the blood collecting needle is stung into 
blood tube of the blood donor, and the blood of the blood donor is 
absorbed into the blood collecting bag by making the inside of the case in 
which the above-described blood collecting bag is received in a negative 
pressure. When the blood of a predetermined amount has been absorbed in 
the blood collecting bag, blood collecting procedure is stopped, and the 
intermediate part of the above-described vinyl tube is closed. Thereby, 
the flow out of the blood in the blood collecting bag through the vinyl 
tube is prevented, and the entrance of external atmosphere into the blood 
collecting bag is made not to occur. 
In order to shut the intermediate part of the vinyl tube and the like such 
as described above hermetically, a welding device utilizing the high 
frequency dielectric heating method has been hitherto used. 
the vinyl tube welding device with use of the high frequency dielectric 
heating method is equipped with a pair of electrodes, and formed so that 
vinyl tube and the like are put between these electrodes, and high 
frequency current is supplied between both electrodes. 
As a result, the vinyl tube put between both electrodes is heated by 
dielectric loss and temperature is raised, and the softened vinyl tube is 
pressed between the above-described one pair of electrodes and is welded. 
A vinyl tube welding device with the high frequency dielectric heating 
method, and a comparatively simple construction is disclosed in the 
Japanese Utility Model Application Laid-Open No. 43101/1979. 
This conventional welding device for tube is constituted, as shown in FIG. 
7, of a control box 1 built-in with a high frequency wave generation 
source, a pair of levers 6 mutually displacing by making rotation axis 5 
as the center, a pair of electrodes 2 and 2 (welding part 3) provided at 
the tip part of 6, and the cable 4 for connecting this welding part 3 to 
the above-described control box 1. 
In the case of welding the tube, the intermediate part of the tube is put 
between the electrodes 2 and 2, and high frequency current is supplied 
from the control box 1 between the electrodes 2 and 2 through the cable 4. 
As a result, the vinyl tube or the like is softened by the heating due to 
the high frequency dielectrics and is pressed between the electrodes and 
welded. 
According to this conventional device, the force applied to the levers 6 
and 6 becomes the force of pressing the tube between pair of electrodes 2 
and 2, and there is generated the difference of pressing force of the tue 
by the grasping force of the operator grasping the levers 6 and 6. 
Therefore, in the case of carrying out the welding of many tubes, 
fluctuation is generated in welding, and skill is required in order to 
carry out good welding safely. 
SUMMARY OF THE INVENTION 
An object of the present invention resides in proposing a welding device 
for tube which can always put the tube between with uniform force, and can 
weld the tube surely and in a stabilized state. 
The welding device for tube of the present invention is a portable type 
device and is equipped with 
a first electrode supported on a end surface of the main body case; 
a movable member set by counterposing to the end surface of the 
above-described main body case; 
a second electrode supported at a position counterposing to the 
above-described first electrode in the above-described movable member; 
a manipulation member for displacing the above-described movable member to 
forward and backward directions toward the end surface of the main body 
case; 
a first elastic member for making said manipulation member return to a 
predetermined position, when the above-described manipulation member is 
released; and 
a second elastic member for endowing elasticity to the displacement 
direction of the above-described movable member, when the above-described 
movable member is made approach to the end surface direction of the main 
body case.

DESCRIPTION PREFERRED EMBODIMENTS 
FIG. 1 shows a first embodiment of the present invention. This welding 
device for tube is equipped with a main body case 7, a movable plate 10, 
and a lever 12. In the inside of the main body case 7, a high frequency 
oscillation circuit (not shown in the figure) and the like are provided, 
and on one end surface 8 of that main body case 7, a first electrode 9 is 
supported. 
On the lower end part of the movable plate 10, an arm part 10a is extruded. 
This arm part 10s is supported on the main body case 7 and is displaceable 
along the lengthwise direction of the main body case side surface part. On 
the inside surface of the movable plate 10, a second electrode 11 is 
provided at the part counterfacing to the first electrode 9. 
The manipulation lever 12 has a support piece 12a with an end part pivoted 
on the side surface part of the main body case 7. A pulling spring 13 is 
provided between the intermediate part of this support piece 12a and the 
base end part of a movable arm part 10a. When the manipulation lever 12 is 
rotated in the direction of the arrow mark a of FIG. 1, the movable plate 
10 displaces in the direction of the end surface 8 of the main body case, 
and the second electrode 11 elastically approaches the first electrode 9. 
Also, between the main body case 7 and the middle part of the manipulation 
lever support piece 12a, another pulling spring 14 is provided and has an 
elastic force which is opposite to the direction to the arrow mark a. By 
the pulling spring 14, the manipulation lever 12 always return to a 
predetermined position. When the manipulation lever 12 returns to the 
predetermined position, the second electrode 11 separates from the first 
electrode 9 by a predetermined distance. Since he pulling spring 14 
becomes in a closely adhered winding in free state, accompanying to the 
return of the manipulation lever 12, it pushes the movable plate 10, and 
makes the first and second electrodes 9 and 11 separated. The return 
position of the manipulation lever 12 is restricted by a stopper or the 
like not shown in the figure. 
When the welding device for tube is operated, the manipulation lever 12 is 
manipulated in the state where the grip 15 is grasped. 
While it is not shown in the figure, the movable plate arm part 10a can be 
provided at the opposite side of the movable plate 10, and in the same 
manner the pulling springs 13 and 14 can be provided on the opposite side 
of the main body case 7. 
In the case when the intermediate part of the tube made of heat weldable 
material is welded by the welding device for tube shown in FIG. 1, after 
inserting the tube between the first electrode 9 and the second electrode 
11, the manipulation lever 12 is rotated in the direction of the arrow 
mark a of FIG. 1. As a result, the movable plate 10 displaces to one end 
surface 8 of the main body case, and the intermediate part of the 
above-described tube is located between the second electrode 11 and the 
first electrode 9 supported on the inside surface of this movable plate 
10. 
In this state, since the prescribed elastic force accompanying to the 
elongation of the pulling spring 13 has been added to the tube, the tube 
becomes pressed with an approximately constant force, regardless of 
different strength of the rotational movement of the manipulation lever 12 
provided by the operator. Also, for example, by providing a stopper or the 
like not shown in the figure, the displacement amount of the manipulation 
lever 12 can be suitably regulated. 
When high frequency current is passed between the first and second 
electrodes 9 and 11 with the high frequency oscillation circuit provided 
in the main body case 7, the above described tube is heated and the 
temperature is raised, and it is pressed and welded between the 
above-described first and second electrodes 9 and 11. 
After the tube has been welded and the force added to the manipulation 
lever 12 is released, the manipulation lever 12 is pulled back by the 
elastic force of the pulling spring 14 and the second electrode 11 and the 
first electrode 9 separate. The welded tube can be taken out from between 
both electrodes 11 and 9. 
A second embodiment of the present invention is shown in FIG. 2. In this 
embodiment, an alternate mechanism 16 is provided in the main body case 7 
for forming the welding device for tube. The mechanism 16 is hitherto 
build in the magnet catch provided in a sharp pencil, ball pen, various 
kinds of cabinet, etc. and repeats elongation and shrinkage corresponding 
to the compression force repeatingly added. In this mechanism 16 the total 
length shrinks when compression force is once added in the axial direction 
(left and right direction of FIG. 2), and when the compression force is 
added again the total length increases. In the mechanism 16, its end part 
(right end part in FIG. 2) is connected to the main body case 7, and its 
another part (left end part in FIG. 2) is connected to the connection 
piece 17 for connection to the pulling spring 13 pivoted on the 
intermediate part of the manipulation lever 12. The other structure of the 
welding device for tube is the same as that shown in FIG. 1. 
The welding a tube made of a heat weldable material with the use of the 
welding device for tube of FIG. 2 is almost same as that in the case of 
the welding device for tube of the above-described first embodiment. After 
inserting the tube 18 between the first and second electrodes as shown in 
FIG. 2, the manipulation lever 12 is rotated with fingers so that the grip 
15 is grasped, from the position shown by a solid line in FIG. 2 to the 
position shown with a chain line. 
As a result, via the pulling spring 13 as a elastic member, the movable 
plate 10 is pulled, and the second electrode 11 supported on the inside 
surface of this movable plate 10 is displaced toward the first electrode 
9. Then, the intermediate part of the tube 18 is put between the first and 
second electrodes 9 and 11, and the intermediate part of the tube 18 is 
welded by the above-described high frequency heating. 
In the welding device for tube of FIG. 2, when the total length of the 
alternate mechanism 16 shrinks by rotating the manipulation lever 12 to 
the chain line position of FIG. 2, even after the release of the rotation 
force added to the manipulation lever 12 the manipulation lever 12 is 
supported in the chain line state of FIG. 2. Therefore, the second 
electrode 11 is pushed toward the first electrode 9 always with a constant 
force based on the elastic force of the pulling spring 13. As a result, 
the fluctuation of the welding of the tube becomes perfectly absent, and 
stabilized and sure welding can be always carried out. 
When the desired position of the tube 18 has been welded, the manipulation 
lever 12 is operated once more, and pressing force is again added to the 
alternate mechanism 16 so that the mechanism 16 is elongated. As a result 
of elongation of the mechanism 16, the lever 12 is returned to the solid 
line position of FIG. 2 and the second electrode 11 separates from the 
first electrode 9. 
FIG. 3 shows a third embodiment of the present invention. In this 
embodiment, a binding piece 17 is provided in the intermediate part of the 
manipulation lever 12, and an adsorption place 19 of a magnetic member 
made of iron or the like is mounted. Also, at a position counterposing to 
the adsorption plate 19 inside of the main body case 7, a permanent magnet 
20 is mounted. The permanent magnet 20 has a magnetic force capable of 
supporting the adsorption plate 19 in the state as it has adsorbed this 
adsorption plate 19, regardless of the elastic force of the 
above-described pulling spring 14. 
At the rear end part (right end part in FIG. 3) of the main body case 7, a 
pressing rod 21 as a releasing member extends in the axial direction (left 
and right direction in FIG. 3) and is free to displace. The rear end part 
of this pressing rod 21 is protruded from the rear end part of the 
above-described main body case 7, and by pushing this protruded part 
forward (left side in FIG. 3), the above-described adsorption plate can be 
pushed forward. 
In the welding device for tube shown in FIG. 3, when the manipulation lever 
12 is rotated to the chain line position of FIG. 3, the absorption plate 
19 mounted on the binding piece 17 of the manipulation lever 12 is 
absorbed on the permanent magnet 20 after releasing the force added to the 
manipulation lever 12, the manipulation lever 12 is preserved at the 
position as it is. Therefore, the tube 18 is pressed with a constant force 
between the first and second electrode 9 and 11, and the welding of the 
tube 18 can be carried out without fluctuation and always in a stabilized 
state. 
When the tube 18 has been welded, the rear end part of the pressing rod 21 
is pushed forward, and the adsorption pale 19 is separated from the 
permanent magnet 20. As a result, the above-described manipulation lever 
12 is returned to the position shown by a solid line in FIG. 3 by the 
elastic force of the pulling spring 14, and the second electrode 11 is 
separated from the first electrode 9. The structure of the welding device 
for tube and others are same with those in FIG. 1. 
FIG. 4 shows a fourth embodiment of the present invention. In this 
embodiment, the pressing rod 21 in the above-described third embodiment 
was omitted, and in place of it, a coil 23 is wound on the iron cores 22 
contacting the permanent magnet to form an electromagnet 24. By selecting 
the winding direction or current direction suitably, a magnetic field 
opposite to the magnetic field formed by the permanent magnet 20 is formed 
when the switch 24a is closed and current is supplied to the coil 23. 
Therefore, when the adsorption of the adsorption plate 19 and the permanent 
magnet 20 is released and current is passed to the electromagnet 24, the 
magnetic field formed by the electromagnet 24 cancels the magnetic field 
formed by the permanent magnet 20, and the adsorption plate 19 separates 
from the permanent magnet 20. Structure and action other than that are the 
same as those of the above-described third embodiment. 
As a variation example of the above-described fourth embodiment, the 
permanent magnet 20 is omitted, and the adsorption plate 19 is made 
capable of adsorbing only in the case of passing current to the 
electromagnet 24. During the release of current passage to the 
electromagnet 24, the adsorption of the adsorption plate 19 is released. 
FIG. 5 shows a fifth embodiment of the present invention. In this 
embodiment, in the intermediate part of the manipulation lever 12, a 
hooking member 26 is pivoted, and in the rear end part (right end part of 
FIG. 5) of the hooking member 26 a nail part 25 is formed. Also, in the 
position corresponding to the hooking member nail part 25 of the main body 
case 7, a solenoid 27 for making release means is provided, and the 
stopper member 28 for displacing by the solenoid 27 is hooked to the 
hooking member nail part 25. 
The stopper member 28 hooks to the hooking member nail part 25 during to 
the rotation of the manipulation lever 12 against the elastic force of the 
pulling spring 14 when current is not supplied to a solenoid 27. During 
the current passage to the solenoid 27, the stopper member 28 is displaced 
and the hook to the hooking rear part slips out. 
According to the embodiment of FIG. 5, the force for pressing the first and 
second electrodes 9 and 11 (cf. FIGS. 1 to 3) relative to each other can 
be made always constant. Also, as the version example of FIG. 5, the 
apparatus can be formed so that when the distance between the first 
electrode 9 and the second electrode 11 has become less than a constant 
value, the solenoid 27 automatically passes current, and after completion 
of the welding the first and second electrodes 9 and 11 are automatically 
separated. 
In any of the above-described embodiments, one end of the manipulation 
lever 12 is pivoted in the main body case 27. However as shown in FIG. 6, 
the apparatus can be also constructed in such a manner that a guide rod 29 
fixed to the manipulation lever 12 is inserted into the thrust bearing 30 
n the grip 15, and the manipulation lever 12 is linearly displaced. In 
FIG. 6 the upper end part of the manipulation lever 12 is connected to the 
alternate mechanism 16. 
In FIG. 6 when the manipulation lever 12 is pulled with fingers to the 
right direction, the movable plate 10 provided with the second electrode 
11 displaces to the right. After the tube to be welded is supported in the 
most suitable interval between the first and second electrode the high 
frequency is oscillated, and sealing is carried out. During the 
oscillation with the high frequency, it is displayed (not shown by the 
figure) with an emission diode (LED). When the emission diode is out of 
lights or discolored, the oscillation of the high frequency is finished 
and the sealing action is completed. By pulling the manipulation lever 12, 
the gap between the first electrode and the second electrode is released 
by the mechanism 16, and is returned to the original position. 
In the above-described embodiments, the devices are provided with the high 
frequency oscillation circuit and an electric source circuit. The electric 
source part may be connected to an outside cable, but a small high 
performance battery capable of charging can be mounted also. For example, 
in FIG. 1, a battery mounting room 15a is provided in the main body case 
15, and the battery can be arranged therein. 
With the above-described welding device for tubes in accordance with the 
present invention, notwithstanding whether the operator is skilled or not, 
the tube can be held always with a uniform force, and a sure and stable 
welding can be carried out. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described an embodied in a 
welding device for tubes, it is not intended to be limited to the details 
shown, since various modifications and structural changes may be made 
without departing in any way from the spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various application without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention. 
What is claimed as new and desired to be protected by Letters Patent is set 
forth in the appended claims.