GB2295574A

GB2295574A - Welding apparatus

Info

Publication number: GB2295574A
Application number: GB9522092A
Authority: GB
Inventors: Taichi Iimura; Atsushi Ishii
Original assignee: Tomy Co Ltd
Current assignee: Tomy Co Ltd
Priority date: 1994-12-02
Filing date: 1995-10-27
Publication date: 1996-06-05
Anticipated expiration: 2015-10-27
Also published as: HK1009945A1; JP3011982U; GB9522092D0; GB2295574B

Abstract

A welding apparatus 1 comprises a plate 3 for holding an object P to be welded and a body 2 with a heater (91, Figure 4) and means for positioning the holding plate 3 and the heater (91) such that the heater is exposed to the object through a window 31 in the plate. Preferably the body comprises a port 4 through which the plate is inserted and means for providing relative movement such that the heater moves along the window in the plate. <IMAGE>

Description

DESCRIPTION WELDING APPARATUS The present invention is a welding apparatus.

Known welding apparatuses are disclosed in Japanese Utility Model publications 26086/1991 and 32102/1983.

In such conventional welding apparatus a body is provided with a covering lid and a heater for welding is positioned within or at the top of a lid on the body. In such conventional welding apparatus, a portion of the material to be welded may deviate from what is desired or become wrinkled as the lid is positioned over the welding object. It is usually impossible to directly, visually confirm that the portion to be welded is properly positioned and, if the alignment is incorrect, it is difficult to correct the "set" position. In addition to the foregoing, during the continuous welding operation, there is always a danger that the operator may touch the heater and be burned. With the present invention, these and other problems are solved.In accordance with the teachings of the present invention in their broader concepts there is provided a plate for holding the object to be welded and a body having a mechanism for positioning the holding plate and the heater, including a window within the holding plate exposing the surface of a portion of the object to be welded, the heater being in close contact with the surface and being exposed to the heater. There is also provided a holding-plate mechanism for carrying the holding-plate such that the heater moves relatively along the window, and wherein the body is provided with an insertion port into which the holding-plate is inserted and, in addition, a port for extracting the holding-plate and a carrying route connecting the insertion port with the extraction port.

Still further, the welding apparatus of the present invention includes a first sensor for detecting that the holding-plate is inserted into the insertion port and for outputting a detection signal showing the result, a second sensor for detecting that the head of the holding-plate protrudes from the extraction port to a predetermined length and for outputting a detection signal showing the result, and a mechanism for operating the holding-plate carrying mechanism in accordance with a detection signal outputted from the first sensor and for stopping the operation of the holding-plate carrying mechanism in accordance with a detection signal outputted from said second sensor.

The welding apparatus of the present invention will be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view of the welding apparatus of one embodiment of the present invention; Fig. 2 is a perspective view of the holder; Fig. 3(a) is a top view of the holder; Fig. 3(b) is a sectional view of the holder; Fig. 3(c) is a bottom view of the holder; Fig. 4 is a block diagram of the body of the welding apparatus; Fig. 5(a) is a top view of the body; Fig. 5(b) is a side view of the body; Fig. 6(a) is a side view of a heater; Fig. 6(b) is a perspective view of the heater; Fig. 7 is a block diagram of a control circuit; Fig. 8 is a wiring diagram of electrical components; and Figs. 9(a), (b) and (c) are diagrams explaining operational states of the first and second sensor switches.

In Fig. 1 the welding apparatus, generally designated by the reference numeral 1, consists of a body 2 containing a heater 91 (see Fig. 4) and a long holding plate 3 for holding a bag P (eg. a plastic bag).

The body 2 is formed so that the width is slightly smaller than the length and is provided with an insertion port 4 into which the holder 3 is inserted and an extraction port 5 for extracting the holder 3 at the left side (see Fig. 4). The insertion port 4 and the extraction port 5 are connected to each other through a carrying route 6 (see Fig. 4) for carrying the holder 3. Moreover, a grooved slit 7 is formed at the front of the body 2 so that the bag P passes through the slit 7 when the holder 3 is within the body 2.

A control switch 8 (carrying-speed changing means) is located at the top of the body 2. The control switch 8 is used to turn on and off the power supply or to change the carrying speeds for carrying the holder 3 inserted into the insertion port 4. Specifically, by adjusting an alignment mark 9 of the control switch 8 to the position "OFF", the power supply of the body 2 is turned off. By adjusting the mark 9 to the position "LO", the power supply is turned on and the carrying speed is set to a low speed. Moreover, by adjusting the alignment mark 9 to the position "HI", the carrying speed is set to a high speed. It is necessary to adjust the mark 9 to the position "LO" to weld a thick plastic bag or aluminum bag and to the position "HI" to weld a thin plastic bag or the like.Therefore, by changing the carrying speeds in accordance with the type of the bag P, it is possible to weld for the proper time.

By holding the bag P with the holder 3, and by setting the control switch 8 so that the carrying speed corresponds to the type of bag P, and thereafter inserting the holder 3 into the insertion port 4 of the body 2, the holder 3 is automatically carried toward the extraction port 5 in the carrying route 6 and, in this process, the portion of the bag P to be welded held by the holder 3 is welded. All welding operations are completed by extracting the holder 3 from the extraction port 5 and by taking the bag P out of the holder 3.

The holder 3 is provided with a thin top plate 11 and a thin bottom plate 12 made of ABS resin, as shown in Fig. 2. The top plate 11 is connected with the bottom plate 12 by a hinge so that the top plate 11 is rotatable in relationship to the bottom plate 12 about a pin 25. See Fig. 3(b). When the top plate 11 opens, the insides of both plates are almost flat. When the top plate 11 closes, pawls 13 and 13 formed at both ends of the bottom plate 12 fit to notches 14 formed at the ends of the top plate 11 and the plates 11 and 12 contact each other. See Fig. 3 (a) In the case of the bottom plate, as shown in Fig.

3 (b), a hill (of projection) 22 extending in the longitudinal direction of the holder 3 is formed at the central portion of the inside, and a heat-resistant tape 23 is applied to the hill 22 to cover the hill 22. Moreover, a rubber pad 24 for preventing the bag P from slipping is applied to this side and to the other side of the hill 22, respectively. Moreover, as shown in Fig. 3(c), a rack 26 engaging a pinion 68 (see Fig. 4) is formed as a belt at the bottom of the bottom plate 12 along the longitudinal direction of the holder 3. Furthermore, a linear groove 28 parallel with the rack 26 is formed at the bottom of the plate 12 and a protrusion 30 is formed at a predetermined portion of the groove 28 so that a switch lever 85 (see Fig. 4) , for operating a second sensor switch 76, contacts the protrusion 30.

As shown in Fig. 3(a), the top plate 11 has a window 31 extending in a longitudinal direction at the central portion thereof. The window 31 is located to receive the hill 22 when the top plate 11 closes. The heat-resistant tape 23 protrudes from the window 31 and is almost flush with the surface of the top plate 11.

Moreover, as shown in Fig. 3(b), by setting the bag P so that portion thereof to be welded is set on the hill 22, and thereafter closing the top plate 11, the portion to be welded on the heat-resistant tape 23 is exposed through the window 31 and slightly rises from the surface of the top plate 11 and the heater 91 of the body 2 closely contacting the portion to be welded.

Moreover, a serrated non-slip section 32 (see Fig. 2) is formed at this side and on the other side of the window 31 in the top plate 11, respectively, to fix the bag P by holding it between the non-slip section 32 and the rubber pad 24 of the bottom plate 12 when the top plate 11 closes. Furthermore, heat-resistant tapes 33 are applied onto a line extending from the window 31 on the top plate 11, shown in Fig. 2(a), so that the top plate 11 is not melted when contacting the hot heater 91.

As shown in Fig. 4, the body 2 is provided with a bottom frame 41 and a top frame 42 secured by four tapping screws and diaphragms 43 and 44 forming the carrying route.

First to sixth bearing plates 45 to 50 for supporting motors and gears are vertically mounted to the bottom frame 41. The first and second bearing plates 45 and 46 support a motor 51 which serves as a driving source for moving the holder 3 and a shaft 52 and a pinion 53 secured to the shaft of the motor 51 which engages a first gear 54 secured to the shaft 52.

The first gear 54 is fitted into a notch 100 of a speed changing slider 98, described hereinafter, with a "play" so that it can slide in the axial direction of the shaft 52 together with the shaft 52 and a second gear 55 secured to the shaft 52.

The third and fourth bearing plates 47 and 48 support shafts 56 and 57. A crown gear 58, comprising a large-diameter gear and a small-diameter gear to be alternatively engaged with the second gear 55, and a third gear 59, which rotates integrally with the crown gar 58, are secured to the shaft 56. A fourth gear 60 and a fifth gear 61 rotate integrally with the fourth gear 60 are secured to the shaft 57.

Fifth and sixth bearing plates 49 and 50 support a shaft 62. A placing seat 63 is secured to a predetermined position of the shaft 62. Moreover, a push spring 64 with whose one end the placing seat 63 contacts, a sixth gear 65, and a first clutch plate 66, which rotates integrally with the sixth gear 65, are rotatably mounted to the shaft 62. Moreover, a second clutch plate 67 engaging the first clutch plate 66, and the pinion 68 engaging the rack 26 of the holder 3, are secured to the shaft 62. As a result, the sixth gear 65 is pressed by the push spring 64 so as to engage racks 66 and 67. In this case, clutch plates 66 and 67 integrally form a clutch.When the pinion 68 does not rotate because the carrying route 6 is clogged with dust, or the holder 3 is forcibly stopped by hand while the holder 3 is carried, the first clutch plate 66 prevents the motor 51 from "seizing because the plate 66 is disengaged from the second clutch plate 67 and idles. The motor 51, first to sixth gears 54, 55, 59 to 61, and 65, grown gear 58, clutch plates 66 and 67, pinions 53 and 68, and rack 26 constitute the holdingplate carrying "means" of the present device.

The relationship between the above gears is described below by referring to Figs. 5(a) and S (b) The pinion 53 engages with the first gear 54, and the second gear 55 engages with the large-diameter gear of the crown gear 58 when the control switch 8 is set to the position "LO" as shown by a continuous line and engages with the small-diameter gear of the gear 58 when the switch 8 is set to the position "HI" as shown by a dot chain line.

The fourth gear 60 engages with the third gear 59 which rotates integrally with the crown gear 58. The sixth gear 65 engages with the fifth gear 61 which rotates integrally with the fourth gear 60. The second clutch plate 67 engages with the first clutch plate 66 which rotates integrally with the sixth gear 65. When the pinion 68 rotates integrally with the second clutch plate 67, the driving force of the motor 51 is transmitted to the pinion 68.

Moreover, a battery box 71 for storing three batteries 70 is formed on the bottom frame 41 and a battery-box lid 72 is provided for the battery box 71 so that it can open or close.

Furthermore, first support bars 73 and 74 are vertically attached to the bottom frame 41 and first and second sensor switches (first sensor and second sensor) 75 and 76 are attached to the support bars 73 and 74, respectively. The first sensor switch 75 detects that the holder 3 is within the insertion port 4 and the second sensor switch 76 detects that the head of the holder 3 protrudes from the extraction port 5 up to a predetermined length.

The above-described diaphragm 43 is formed stepwise and is provided with a bottom stage 81a, wall 81b, and top stage 81c. The bottom stage 81a and the wall 81b constitute positioning "means" for determining the insertion position of the holder 3 together with a wall 42a at the front of the top frame 42.

Holes 82 and 83 are formed on the bottom stage 81a and pins 86 and 87 are positioned under the holes 82 and 83, respectively. The pins 86 and 87 support the first and second switch levers 84 and 85 for turning on the second sensor switches 75 and 76, respectively, so that the levers 84 and 85 can enter or come out of the holes 82 and 83. Moreover, a square hole 88 is formed on the bottom stage 81a and the top of the pinion 68 protrudes from the hole 88 engaging the rack 26 of the holder 3. As shown in Figs. 9(a) to 9(c), when the holder 3 is inserted into the insertion port 4 of the body 2 so that the rack 26 engages the pinion 68, the first switch lever 84 enters the hole 82 to operate the first sensor switch 75.Moreover, when the rear end of the holder 3 passes over the pinion 68 and the head of the holder 3 protrudes from the extraction port 5 up to a length (predetermined) necessary to extract the holder 3, the second switch lever 85 contacts the protrusion 30 on the groove 28 of the holder 3 and enters the hole 82 to operate the second sensor switch 76.

The diaphragm 44 is attached to the top frame 42 so as to be parallel with the bottom stage 81a and located at the middle of the wall 81b, forming the carrying route 6 together with the bottom stage 81a, wall 81b, and the front wall of the top frame 42. A hole 90 is formed around the central portion of the diaphragm 44, into which the heater 91 is positioned.

As shown in Fig. 6(a), the heater 91 is supported by a coil spring 92 whose one end is set to the inner surface of the top frame 2 and pressed by the spring 92 in the direction of the carrying route 6.

As shown in Figs. 6(a) and 6(b), the heater 91 is provided with a box-like body 111 made of a thermosetting resin such as phenol resin and is provided with a protrusion 112 extending in the longitudinal direction formed at the bottom of the protrusion 112. A planar Nichrome wire 113 serving as a heating source is applied to the surface of the protrusion 112 and both ends of the planar Nichrom wire 113 are secured to the right and left sides of the body 111. Moreover, the planar Nichrome wire 113 located at the bottom of the body 111 is covered with a heat-resistant tape 114. Furthermore, the ends of metallic pieces 115 are secured to both ends of the planar Nichrome wire 113, respectively. Heat-resistant lead wires 116 and 116 are soldered to the other ends of the metallic pieces 115 and 115.

The heat-resistant lead wires 116 are connected to an electric circuit board 117. See Fig. 5(a).

Furthermore, the body 111 is covered with a box-like case 118 and made of a thermosetting resin. The heatresistant tape 114 of the body 111 protrudes from a hole 119 formed at the bottom of the case 118. As a result, the bottom of the heater 91 protrudes through the hole 90 of the diaphragm 44 and the heat-resistant tape 114 protrudes from the hole 119 of the case 118, and contacts the portion of the bag P to be welded exposed to the window 31 of the holder 3.

The top frame 42 is provided with a hole 93. The top of the control switch 8 mounted on the top stage 81c of the diaphragm 43 protrudes from the hole 93. A cam 94 is formed in a predetermined range on the outer periphery of the control switch 8. By setting the control switch 8 to the position of "LO" and "HI", a power supply 95 set beside the control switch 8 is turned on when the cam 94 contacts the power supply 95.

A hole 96 is formed on the control switch 8. One end of a helical coil spring 97 is hooked within the hole 96. The other end of the helical coil spring 97 is hooked on a pin 99 vertically set at the top of the speed changing slider 98 which is slidably set along the wall 81b of the diaphragm 43. As a result, by setting the control switch 8 to the position "LO" from the position "OFF", the speed changing slider 98 is moved leftward by the pressure of the helical coil spring 97. The first gear 54 fitted to the notch 100 of the speed changing slider 98 slides leftward, and the second gear 55, set to the same shaft as the first gear 54, engages the large-diameter of the crown gear 58.By resetting the control switch 8 to the position "HI" from the position "LO", the sped changing slider 98 slides further leftward and the second gear 55 engages the small-diameter gear of the crown gear 58.

A control circuit 120 mounted on the abovedescribed electric circuit board 117 is described below, with reference to the block diagram in Fig. 7.

As shown in Fig. 7, the batteries 70 are connected to a power supply line 121 through the switch 95 and the first and second sensor switches 75 and 76 are connected to the input section of a heating control section (heating control means, timer) 122. Moreover, the output section of the heating control section 122 is connected to a current driver 123 and, moreover, the planar Nichrome wire 113 and a series circuit of a voltage stabilizer 124 and the motor 51 are connected between the power supply line 121 and the output section of the current driver 123. The heating control section 122 controls the operation of the heater 91 and the motor 51 as described later.

In the control circuit 120, when the power supply switch 95 is turned on, in other words, when the control switch 8 is set to the position "LO" or "HI", the voltages of the batteries 70 are applied to the heating control section 122. Thus, when the first sensor switch 75 is turned on, the heating control section 122 starts operating the timer and outputs a high-level voltage to the current drive 123 for 30 seconds. During this period, when the second sensor switch 76 is turned on, the heating control section 122 stops operating the time to stop outputting the highlevel voltage.When the current driver 122 receives the high-level voltage, it supplies current to the planar Nichrome wire 113 to heat the wire and moreover supplies current to the motor 51 to operate the motor by introducing the current to the inside through the output section. When 30 seconds passes after the operation of the timer is started or the second sensor switch 76 is turned on, the heating operation of the planar Nichrome wire 113 and the rotation of the motor 51 are stopped because the heating control section i22 outputs a low-level voltage to the current driver 123 and thereby the current driver stops receiving the current.

In this case, the operation of the planar Nichrome wire 113 and the motor 51 are stopped when 30 seconds passes after the first sensor switch 75 is turned on.

That is, when the carrying route 6 is clogged with dust or the holder 3 is forcibly stopped by hand while the holder 3 is carried, the clutch plates 66 and 67 are disengaged from each other and the holder 3 stops in the carrying route 6. When this continues, the motor 51 is overloaded and heated and, moreover, the planar Ni chrome wire 113 is overheated because it continuously operates. Therefore, to prevent the motor and the wire from over heating, the output of a high-level voltage from the heating control section 122 is stopped when 30 seconds passes to stop the operation of the planar Nichrome wire 113 and the motor 5.

The time of 30 seconds is selected because it takes up to 30 seconds to complete the welding of a thick bag at the position "LO". In this case, it is also possible to form a structure so that the timer time can be changed correspondingly to the "set" position of the control switch 8. That is, it is possible to automatically change the timer time whenever the set positions of the control switch 8 are changed as follows: the timer time is set to 30 seconds when the control switch 8 is set to the position "LO" and to 18 seconds when the switch 8 is set to the position "HI".

Operation of the welding apparatus 1 will herein be described. First, the top plate 11 of the holder 3 is opened to position a welding object so that the portion to be welded is set on the hill 22 of the bottom plate 12 and the holder 3 is closed. In this case, if the portion to be welded is not correctly set, it is necessary to set the object again. Because the portion to be welded can be directly, visually confirmed through the window 31 when the bag P is held by the holder 3, it is possible to easily correct the position if the welding portion of the bag P is not properly positioned.

Then the control switch 8 is set to the position "LO" or "HI" to select a carrying speed and, thereafter, the holder 3 is inserted into the insertion port 4 of the body 2. As shown in Fig. 9(a), before the holder 3 is inserted into the port 4, both the first and second switch levers 84 and 85 are located at the normal position and both the first and sensor switches 75 and 76 are turned off. When the holder 3 is inserted into the port 4, the pinion 68 engages the rack 26, the first switch lever 84 contacts the left side of the holder 3 and rotates, and thereby, the first sensor switch 75 is turned on, the heating control section 122 operates, and the planar Nichrome wire 113 is heated and the motor 51 rotates. As a result, the holder 3 is carried on the carrying route 6 while the portion of the bag P to be welded is welded.

When the holder 3 is further carried, the state shown in Fig. 9(b) is set and the first sensor switch 75 is kept turned-on. The second switch lever fits into the groove 28 and slightly rotates, but the second sensor switch 76 is kept turned-off because the second switch lever does not contact the second sensor switch 76.

When the holder 3 is further carried, the rack 26 is disengaged from the pinion 68 and the state shown in Fig. 9(c) is set. Under this state, the first switch lever 84 recovers to the normal state, the first sensor switch 75 is turned off, and the second switch lever 85 contacts the protrusion 30 of the second groove 28 and thereby rotates to turn on the second sensor switch 76.

When the second sensor switch 76 is turned on, the heating control section 122 stops its operation and, moreover, the planar Nichrome wire 113 and the motor 51 stop their operations. In this case, the head of the holder 3 protrudes from the extraction port 5.

Therefore, it is possible to easily extract the holder 3 from the extraction port 5. Then, the bag P is removed from the holder 3 and the welding operation is completed.

As described above, this embodiment of the present invention makes it possible to accurately position the bag P in the holder 3 because the holder 3 is separate from the body and thereby the operator can directly view the portion to be welded through the window 31.

Moreover, even if the bag P is incorrectly set, the position of the bag P can easily be corrected.

Furthermore, by inserting the holder 3 into the insertion port 4 of the body 2, the heating control section 122 operates the motor 51 and the heater 91 in accordance with a detection signal outputted from the first sensor switch 75 automatically stopping the operation of the motor 51 and the heater 91 in accordance with a detection signal outputted from the second sensor switch 76. When welding is completed, the holder 3 is extracted from the extraction port 5 and the bag P is taken out of the insertion port 4.

Because the bag P is automatically carried and welded only by inserting the holder 3 into the insertion port 4 as described above, welding can easily be performed.

Moreover, it is unnecessary to perform operations near the heater 91 in any of the stages. The operator does not touch the heater 91 and therefore, he can safely perform the continuous welding operation. Furthermore, because the motor 51 and the heater 91 are automatically stopped, electric power is saved and overheating is prevented.

Still further, when the set time (30 seconds for this embodiment) has passed since a detection signal was outputted from the first sensor 75, the heating control section 122 stops the operation of the holder 3 and the heater 91. Therefore, even if the holder 3 is caught by the carrying route 6 due to clogging with dust, for example, it is possible to prevent the motor 51 and the heater 91 from overheating.

On this embodiment, the carrying route 6 is formed by the fixed diaphragms 43 and 44 and welding is performed while carrying the holder 3 along the carrying route 6. However, the structure is not restricted to the above. For example, it is also possible to use an openable lid with the top frame 42 and the diaphragm 44, setting a member for positioning the holder 3 on the diaphragm 43, and, moreover, setting a heater with a length equal to the longitudinal direction of the window 31 on the lid to quickly weld a portion to be welded by closing the lid and operating the heater.

As described above, because the welding apparatus of the present invention makes it possible to directly, visually observe the portion to be welded when holding the object, it is possible to easily correct the position of the object if the object is not correctly set and also securely and accurately weld the portion.

Moreover, because the welding object is set to the holding plate separate from the body, it is possible to correct a deviation of the object at a position remote from the heater and set the holding plate to the body by a single operation. Therefore, it is possible to safely perform continuous welding.

Claims

1. A welding apparatus provided with a heater to weld a welding object, comprising a holding plate for holding said welding object, a body having positioning means for positioning said holding plate and said heater, said holding plate having a window for exposing the surface of a portion of said welding object to be welded, said heater being in close contact with the surface of said portion to be weldedçwhen in said apparatus being weldedtand being exposed through said window.

2. A welding apparatus as claimed in claim 1, including holding-plate carrying means for carrying said holding plate such that said heater moves relatively along said window, said body being provided with an insertion port into which said holding plate is inserted, an extraction port from which said holding plate is extracted, and a carrying route connecting said insertion port with said extraction port, and wherein said heater is positioned in said body so as to face said carrying route.

3. A welding apparatus as claimed in claim 2, including a first sensor for detecting that said holding plate is inserted into said insertion port and for outputting a detection signal showing the result, a second sensor for detecting that the head of said holding plate protrudes from said extraction port up to a predetermined length and for outputting a detect Ion signal showing the result, and carrying control means for operating said holding-plate carrying means in accordance with a detection signal output from said first sensor and for stopping the operation of said holding-plate carrying means in accordance with a detection signal output from said second sensor.

4. A welding apparatus as claimed in claim 3, including heating control means for operating said heater in accordance with detection signal output from said first sensor and stopping the operation of said heater in accordance with a detection signal output from said second sensor.

5. A welding apparatus as claimed in claim 4, including a timer to which a time required by the time said second sensor outputs a detection signal after said first sensor outputs a detection signal is set, and which stops the operation of said holding-plate carrying means and said heater when said set required time has passed since the detection signal was output from said first sensor.

6. A welding apparatus as claimed in any one of claims 2 to 5, wherein said holding-plate carrying means comprises a motor in said body, a pinion to be driven by the motor, and a rack on said holding plate.

7. A welding apparatus, as claimed in any one of claims 2 to 6, including carrying-speed changing means for changing the carrying speed of said holding-plate carrying means.