JPH0683254U - Automatic welding equipment for welding excess - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Even if the grindstone is consumed or the surface of the base metal is deformed, the grinding removal amount is always kept constant automatically, and when the load reaches the limit value, electronic Prevents damage to the entire equipment by stopping rotation of the grinder, raising and retracting, and stopping traveling. [Structure] A traveling carriage 4 moving at a constant speed along a welding line on a base material surface 50, a lateral movement frame 5 and a lifting mechanism 8 mounted on the traveling carriage, and an electronic grinder fixed to a slider 13 of the lifting mechanism. 15 and a whetstone 17.
A current detecting means for detecting the load current of the electronic grinder 15, a control circuit for controlling the elevating mechanism 8 so as to adjust the grinding amount so that the load current becomes a constant value compared with a set value, and the load current is a limit value. And an overload prevention circuit that outputs operation signals for stopping rotation of the electronic grinder, raising and retracting, and stopping traveling.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an apparatus for automatically grinding a weld surplus on the base metal surface.

[0002]

[Prior art]

 Excessive welding is ground and removed for the purpose of improving the fatigue strength of welded joints, facilitating non-destructive testing of welded parts, or simply eliminating surface irregularities. . It is also common practice to grind the gas-welded weld groove surface or to grind the surface of a cast or forged product. As shown in FIG. 9, the weld surplus 51 protruding in a semicircular shape with a width W 1 and a height b is a weld bead surplus from the base metal surface 50, which is almost flat with the base metal surface. Until then, it was done manually by operating a portable grinder, but it was tried to use the device shown in Fig. 7 to mechanize the conventional manual work.

This device includes a traveling carriage 60 that moves along the welding line direction of the base material surface 50, a lifting mechanism 61 mounted on the traveling carriage 60, and a fixing tool 62 that fixes the lifting carriage 61 to the lifting mechanism 61. The traveling trolley 60 is driven by a traveling motor 65, and the lifting mechanism 61 is manually adjusted. The traveling trolley 60 is composed of a high speed grinder 63 and a grindstone 64 mounted on the grinder 63. FIG. 8 shows an outline of the lifting mechanism. Since the fixture 62 is attached to a block 67 that moves up and down by a screw mechanism 66, turning the knob 68 by hand to the left and right will fix the block 67. The grinder 63 moves up and down via the tool 62, and as a result, it is possible to adjust the amount by which the grindstone 64 grinds the extra deposit 51.

[0004]

[Problems to be solved by the device]

 As the grindstone 64 used for grinding the above-mentioned welding surplus, as shown in FIGS. 10 and 11, a large number of polishing cloth pieces 64b are radially laminated on a circular substrate 64a made of aluminum alloy or the like. Is used for. In this type of grindstone 64, the grinding surface is renewed due to the wear of the polishing cloth 64b accompanying the grinding, so the amount of grinding removal per unit time is remarkably large and the work efficiency is good compared to the conventional resinoid grindstone. However, since the grindstone is inevitably worn out, the operator must always lower the grinder to the surface 50 of the base material in accordance with the wear of the grindstone in the apparatus shown in FIG.

Further, as shown in FIG. 12, when the base material surface 50 is gently curved and deformed by a welding heat to a vertical plane including a welding line, the base material surface 50 is moved as the traveling carriage 60 moves. A complicated manual adjustment of moving the grinder 63 up and down while simultaneously following the deformation of 50 and the wear of the grindstone is required.

In order to save such trouble, it is possible to use a spring, a pneumatic pressure device, or a hydraulic device to grind the grindstone by constantly pressing it with a constant pressure. However, vibration is likely to occur in the spring. However, pneumatic and hydraulic devices are not practical because they become large. Although there may be local protrusions at the seams of the weld beads, etc., if the grindstone during grinding collides with this protrusion, an excessive current will flow to the grinder motor, causing burnout or damage to the grindstone. Debris may scatter and cause danger.

An object of the present invention is to provide an automatic grinding device for welding excess that can constantly keep the amount of grinding removal constant even if the grindstone is worn or the surface of the base material is deformed. To do. It is another object of the present invention to provide an automatic grinding device capable of preventing damage to the entire apparatus by stopping rotation of the electronic grinder, raising and retracting and stopping traveling when the load current of the electronic grinder reaches a limit value. It is a thing.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention comprises a device for grinding and removing welding excess by using an electronic grinder whose load current increases and decreases according to the amount of grinding per unit time. That is, an electronic grinder movably supported in a three-dimensional manner on a traveling carriage that can move at a constant speed along a welding line through a lateral movement frame and an elevating mechanism; and a load current of the electronic grinder is detected. Current detecting means; a current setting value of the electronic grinder and a load current detection value are compared with each other, and a distance between the electronic grinder and a surface of the welding surplus to be ground is adjusted so that the load current becomes a constant value. A control circuit for controlling the elevating mechanism so as to adjust and adjust the grinding amount per unit time; When the load current of the electronic grinder reaches a limit value, the rotation of the electronic grinder is stopped, the ascending / descending and traveling are performed. It is characterized by having an overload prevention circuit that outputs a stop operation signal.

Conventionally, generally used high-speed grinders reduce the rotation speed when trying to increase the amount of grinding removal per unit time, so the grinding force is also lost, but the electronic grinder reduces load current when the rotation speed decreases. It increases and tries to keep the rotation speed constant. Therefore, if the traveling speed of the truck is constant, the amount of grinding removal per unit time and the load current have the relationship shown in FIG.

The present invention utilizes such a characteristic of the electronic grinder, and instead of operating the knob 68 as shown in FIG. 8 to move the grinder up and down, the distance between the electronic grinder and the welding excess is controlled. A lifting mechanism with a built-in lifting motor is used as the lifting mechanism. Although various types of lifting motors can be used, it is the simplest to use an AC reversible motor.

[0011]

[Work]

 The load current of the electronic grinder is detected and compared with the set current value by the comparator.When the actual load current is smaller than the set current value, the electronic grinder is lowered, and conversely the actual load current is larger than the set current value. At this time, the elevating mechanism is controlled so as to raise the electronic grinder. Since the load current of the electronic grinder is kept constant, as long as the traveling speed of the traveling mechanism (traveling vehicle) is constant, a certain amount of excess is always removed by grinding. Further, when the load current of the electronic grinder reaches the limit value, the rotation of the electronic grinder is stopped, the ascending and retracting and the traveling are stopped by the signal from the overload prevention circuit to prevent the damage of the entire device.

[0012]

【Example】

 1 to 3 are a front view, a plan view and a side view of the device of the present invention. In the figure, 1 is a guide rail arranged to move the traveling carriage 4 along the welding line, 2 is a magnet provided at predetermined intervals of the guide rail 1 (vacuum adsorption pad when the base material is a non-magnetic metal) 2) a rack fixed to the upper surface of the guide rail 1, 5 a lateral movement frame provided on the traveling carriage 4, and 6 a traveling mechanism provided at substantially the center of the traveling carriage 4 (FIG. 2). ), 7 is a handle for operating the lateral movement frame 5, 8 is a lifting mechanism attached to the lateral movement frame 5, 10 is an operation panel provided on the upper portion of the traveling carriage 4, and 15 is a lateral direction on the traveling carriage 4. An electronic grinder movably supported three-dimensionally via a moving frame 5 and an elevating mechanism 8, and 17 is a grindstone attached to the end of the electronic grinder body.

The traveling carriage 4 has a plurality of wheels 11 at its lower portion, and these wheels 11 are engaged with guiding grooves 12 provided along the longitudinal direction of both side walls of the guide rail 1. Further, the pinion 20 is projected below the traveling carriage 4 and is engaged with the rack 3 provided on the guide rail. The traveling vehicle 4 has a built-in traveling motor 9 that constitutes the traveling mechanism 6, and the pinion 20 is rotated through a reduction mechanism (not shown) to move the traveling vehicle 4 at a constant speed in the longitudinal direction of the guide rail 1. I am trying to drive it. When the welding surplus is ground, the vehicle is driven at a relatively low speed by the driving motor as described above, but after finishing the grinding, the handle 21 (FIG. 2) attached to the upper part of the main body is operated to rack the pinion 20. It is arranged so that it can be separated from 3 and the traveling carriage 4 can be quickly returned by hand. The operation panel 10 of the traveling carriage 4 has a speed display window 40, a current value setting device 35, a current scale 36 with a load current display, in addition to various switches for rotating the grindstone, driving the lifting mechanism and traveling the carriage. There is.

A holder 16 is provided on the lifting slider 13 of the lifting mechanism 8, and a handle 18 for adjusting the front-back tilt angle and a handle 19 for adjusting the rotation axis tilt angle of the grindstone 17 are attached to the holder 16, and the electronic grinder 15 is tiltable. Support. This elevating mechanism 8 is for controlling the distance in the height direction between the electronic grinder 15 and the surface to be ground of the welding surplus, and ascending / descending to the upper part of the elevating mechanism 8 as schematically shown in FIG. The motor 25 is mounted, the screw rod 26 is directly connected to the motor output shaft, and is screwed to the support block 27 of the slider 13. Since the support block 27 is slidably supported in the vertical direction along the left and right guides 28, the slider 13 can be rotated in the forward or reverse direction via the control circuit 40 (FIG. 6) described later. The holder 16 and the electronic grinder 15 attached to the can be moved up and down.

FIG. 6 is a block diagram showing an arrangement relationship of control circuits and the like when an AC reversible motor is used as the lifting motor 25. The control circuit 40 compares the current setting value of the electronic grinder 15 with the load current detection value, and adjusts the distance between the electronic grinder and the surface of the weld surplus to be ground so that the load current becomes a constant value. That is, it is for controlling the lifting mechanism 8 in order to keep the grinding amount of the electronic grinder 15 per unit time constant, or to adjust the amount, and a rectifying circuit 31 for rectifying the load current of the grinder motor 15a. , A smoothing circuit 32 for removing noise from the rectified output, and a forward / reverse switching unit 38 for determining the forward / reverse rotation of the lifting motor by the output of a comparator 37 for comparing the load current with a set value current. ing.

The motor 15 a of the electronic grinder 15, the traveling motor 9, and the lifting motor 25 are all driven by a power source 30 (for example, AC 100 V) via an overload prevention circuit 33. The traveling motor 9 is rotated at an arbitrary constant speed by another control circuit 41. As described above, the motor 15a of the electronic grinder 15 is kept at a constant rotation speed by the electronic control circuit 42 regardless of the amount of grinding removal per unit time.

At that time, the load current of the grinder motor 15a, which fluctuates as shown in FIG. 4, is detected by the current detection unit (current detection means) 34, passes through the rectifier circuit 31 and the smoothing circuit 32, and the load current display scale is displayed. It is displayed on 36 and sent to the comparator 37. The comparator 37 compares the current value preset in the current value setter 35 with the load current, and when the absolute value of the difference exceeds the value preset by the sensitivity adjustment circuit 39, the forward / reverse switching is performed. A rising or falling signal is output from the device 38.

When the load current of the motor 15a of the electronic grinder exceeds the allowable limit value shown in FIG. 4, the overload prevention circuit 33 operates to stop the rotation of the motor 15a of the grinder 15 and the traveling motor 9. At the same time, the elevating motor 25 is rotated in reverse to elevate and retract the electronic grinder to prevent the burnout of the glidant and the damage of the grindstone.

Next, the operation of the above device will be described. As shown in FIGS. 1 to 3, the guide rail 1 is arranged at a predetermined interval from the welding line on the surface of the base metal and parallel to the welding line, and is supported by the lateral moving frame 5 on the traveling carriage by the handle 7. The elevating mechanism 8 is moved back and forth, and the handles 18 and 19 are operated to correctly position the grindstone 17 just above the welding excess 51 and to perform centering. After doing this, the elevating motor 25 is rotated while driving the electronic grinder 15 to lower the electronic grinder to a height at which the welding surplus 51 is removed and start grinding. After the grinding is started, the traveling motor 9 is driven to rotate the pinion 20 that meshes with the rack 3 to cause the carriage 4 to travel in one direction to remove the welding surplus 51 on the entire length. After the removal, the lever 21 is operated to disengage the pinion and the rack, and the traveling carriage 4 is quickly returned to its original position by manual pushing.

While the traveling carriage 4 is traveling at a constant speed, when the welding surplus 51 is ground, if the base material surface 50 is a flat surface, the electronic grinder 15 is moved up and down so that the load current value becomes constant. The mechanism 8 constantly descends by the amount of wear of the grindstone, so that the amount of grinding removal is kept constant. As shown in Fig. 12, when the base metal surface 50 is deformed such as being gently curved in the vertical plane including the welding line, the grinding wheel wear amount and the grinding removal amount are always followed by the deformation of the base metal surface 50. The elevating mechanism 8 is automatically moved up and down so that e becomes constant. As a result, if the amount b of the extra deposit 51 is substantially constant, it is possible to finish the grinding so that the remaining amount s is constant. Further, when the extra bead width W in FIG. 9 is large, the entire surface of the extra bead 51 can be ground and finished by reciprocating grinding while moving the electronic grinder 15 by the lateral movement frame 5 in the lateral direction. it can.

Further, when a grindstone such as that shown in FIG. 10 is used, the grinding resistance is inevitably increased and the grinder load is inevitably increased when the abrasion of the polishing cloth piece 64b reaches the circular substrate 64a and the grinding becomes impossible. Since the current exceeds the permissible limit value, the overload prevention circuit 33 in FIG. 6 operates to automatically stop the operation of the apparatus, and wait for the replacement of the grindstone. That is, it has automatic stop and fail-safe functions. According to the experimental results, the circuit of FIG. 6 using the AC reversible motor can obtain a finished surface with sufficient smoothness for practical use. However, if the servo motor is used, the control accuracy is further improved and A smooth finished surface can be obtained.

[0022]

[Effect of device]

 As described above, according to the present invention, the electronic grinder, in which the load current increases and decreases according to the magnitude of the grinding amount per unit time, is moved horizontally along the welding line by the horizontal moving frame and the lifting frame. Since it is movably supported in three dimensions via a mechanism, it is possible to automatically grind the weld excess on the base metal surface by driving the traveling carriage and the lifting mechanism with a motor.

Further, since the control circuit for controlling the elevating mechanism is provided so as to adjust the distance between the electronic grinder and the surface to be ground of the welding excess to adjust the grinding amount per unit time, the electronic circuit is provided. When the load current of the grinder is smaller than the set current value, the grinder is lowered, and conversely, when the actual load current is larger than the set current value, the grinder is raised to drive the lifting mechanism and grind a certain amount of excess. Can be removed. In addition, by performing reciprocating grinding while moving the electronic grinder in the lateral direction, it is possible to efficiently carry out the grinding finish of a wide welding excess. Therefore, if the height and width of the surplus are uniform over the entire length of the weld line, such as with beads that are automatically welded, even if the base metal surface is deformed, the weld surplus is accurately ground according to the base metal surface. It is possible. Furthermore, when the load current of the electronic grinder reaches the limit value, the rotation of the electronic grinder is stopped by the signal from the overload prevention circuit, the elevating and retracting, and the traveling are stopped to prevent damage to the entire device. it can.

[Brief description of drawings]

FIG. 1 is a front view of a welding excess grinding device of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view of FIG.

FIG. 4 is a characteristic diagram of an electronic grinder.

FIG. 5 is a schematic side view of a lifting mechanism.

FIG. 6 is a block diagram showing an arrangement relationship of control circuits and the like of the grinding apparatus of the present invention.

FIG. 7 is a side view of a conventional welding excess grinding machine.

FIG. 8 is a schematic side view of a lifting mechanism in a conventional welding excess grinding apparatus.

FIG. 9 is an enlarged cross-sectional view of a weld overlay.

FIG. 10 is a plan view of a grindstone.

11 is a sectional view of FIG.

FIG. 12 is a vertical cross-sectional view of a welded extraordinary view exaggeratedly showing a pattern in which the surface of the base material is deformed.

[Explanation of symbols]

 4 Traveling dolly 5 Lateral moving frame 6 Traveling mechanism 7 Handle 8 Lifting mechanism 9 Traveling motor 13 Lifting slider 15 Electronic grinder 15a Grinder motor 16 Holder 17 Grinding wheel 20 Pinion 25 Lifting motor 33 Overload prevention circuit 34 Current detector 35 Current Value setter 40 Control circuit 50 Base metal surface 51 Weld surplus.

Claims (1)

[Scope of utility model registration request] 1. A device for grinding and removing welding surplus by using an electronic grinder whose load current increases and decreases according to the amount of grinding per unit time, and can move at a constant speed along a welding line. An electronic grinder movably supported three-dimensionally on a traveling carriage via a lateral movement frame and an elevating mechanism, a current detecting means for detecting a load current of the electronic grinder, a current set value and a load current of the electronic grinder. By comparing the detected value and the load current to a constant value, the distance between the electronic grinder and the surface to be ground of the welding surplus is adjusted to adjust the grinding amount per unit time to increase or decrease the lifting mechanism. A control circuit for controlling, when the load current of the electronic grinder reaches a limit value,
And an overload prevention circuit that outputs operation signals for stopping rotation of the electronic grinder, raising and retracting, and stopping traveling of the electronic grinder.