GB2321028A

GB2321028A - Grinder.

Info

Publication number: GB2321028A
Application number: GB9805458A
Authority: GB
Inventors: Tadashi Taninaga; Tatsushi Ito; Masakazu Kozono
Original assignee: Komatsu Ltd
Current assignee: Komatsu Ltd
Priority date: 1995-11-02
Filing date: 1996-10-02
Publication date: 1998-07-15
Also published as: GB9805458D0; JPH09123060A; WO1997016283A1; DE19681380T1

Abstract

A grinder is supported by a main body frame in such a manner as to be capable of moving up and down, and press force of a rotary grindstone of this grinder to a work W is regulated by an air cylinder and a pressure regulating valve. A hood is supported on the main body frame through a coil spring in such a manner as to cover this rotary grindstone, and the lower surface of the hood is always kept in close contact with the surface of the work W during grinding so as to recover the chips generated during grinding by a dust collector. A brush equipped with a hood is independently supported at the back of the grinder and fine chips adhering to the surface of the work W due to oil, etc., is removed and recovered by a dust collector. This simple construction can prevent scatter of the chips occurring during grinding and can reliably remove the chips.

Description

GRINDING MACHINE Technical Field The present invention relates to a grinding machine and more particularly to a grinding machine for use in finishing thin sheet metals by grinding excess weld metals, penetration beads, deformed parts and the like.

Background Art Grinding by use of a grinding machine of the above type causes chip generation that reduces the efficiency of the grinding machine and pollutes the working environment. Removal of chips is therefore inevitable particularly in such operation as pressing work in which fine chip generation makes lots of troubles. In thin sheetmetal work, the surface of a workpiece is usually covered with oil, which makes it difficult to get rid of chips with a simple air blower.

There have been proposed several methods for removing chips during grinding. One of the well-known methods is the so-called wet dust collection method in which a machine tool is entirely covered and a liquid such as water or oil is circulated to clean the tools. This dust collection method for machine tools is, however, not applicable to grinding machines which carry a grinding tool such as a grinder and therefore another method is usually adapted for grinding machines, in which the whole work object is cleaned by a specialized cleaner in the post treatment after completion of grinding operation.

Another measure for hand tools has been disclosed in Japanese Patent Laid-Open Publication No. 47-31278 (1972) according to which, a cover and a dust collector are attached to the grinder to collect chips being generated during a grinding operation.

The above method using a specialized cleaner to clean the work object in the post treatment disadvantageously requires a cleaner in which the whole work object can be accommodated even when the area to be ground, that is, the area in which chip generation takes place, is small. This leads to a poor operational efficiency and an inevitable increase in the cost.

The method disclosed in the above publication which utilizes a cover for the grinder and a dust collector for sucking chips fails in achieving positive prevention of scattering of chips and satisfactory chip removal by suction.

The invention has been made with the purpose of overcoming the above problems and one of the objects of the invention is therefore to provide a grinding machine of a simple structure capable of positively preventing scattering of chips generated during grinding and ensuring chip removal.

Disclosure of the Invention The above object can be achieved by a grinding machine according to the invention, which comprises a grinding tool supported by a main body frame, a hood with an outlet arranged so as to cover a rotating tool section of the grinding tool and a dust collector connected to the outlet of the hood, characterized in that the hood is supported by the main body frame through resilient supporting means, independently of the grinding tool.

According to the invention, since the hood covering the rotating tool section of the grinding tool is supported by the main body frame through the resilient supporting means, being independent of the grinding tool, the surface of the workpiece (work object) can be ground, with the hood being kept in close contact with the surface of the workpiece. With this arrangement, chips generated during grinding can be prevented from scattering by means of the hood and the chips collected within the hood are positively sucked by the dust collector through the outlet. In the invention, as the hood and the grinding tool are separately supported, the reactive force working on the hood from the workpiece does not affect the grinding operation carried out by the grinding tool.

In the invention, the grinding tool is preferably supported by the main body frame through pressing force regulating means that regulates a pressing force applied to the surface of the workpiece to be ground. This enables it to always adjust the pressing force of the grinding tool exerted on the surface of the workpiece to a proper value and as a result, stable grinding operation can be achieved.

Preferably, the grinding tool consists of a grinder having a disk-like grindstone and is supported such that the wheel face of the grinder is inclined backwardly toward the grinding face of the workpiece. With this arrangement, grinding can be effectively performed by the rear part of the rotating, disk-like wheel face, while chips are being removed.

The hood preferably includes a dust chamber formed therein and having a substantially rectangular section, the section extending parallel with the wheel face of the grinder. The provision of the dust chamber having a substantially rectangular section has such an effect that chips generated during grinding are guided to the outlet after their kinetic energy is absorbed by letting the chips strike against the side walls of the dust chamber, so that more effective chip suction is enabled.

Additionally, the section of the dust chamber, which is perpendicular to the wheel face, is substantially trapezoidal in shape and tapered so as to be widened forward. This allows the surface of the workpiece to be positively ground by the rear part of the wheel face.

A preferred embodiment of the invention may include a brush unit for cleaning the surface of the workpiece after completion of grinding operation performed by the grinding tool, the brush unit being located behind the grinding tool with respect to the grinding direction. The brush unit is supported by the main body frame through resilient supporting means, being independent of the grinding tool. This allows the brush unit to follow the surface of the workpiece independently of the grinding tool, which ensures, as a result, more effective removal of chips.

The brush unit may comprise a substantially tubular brush that is rotatable about a horizontal axis perpendicular to the grinding direction and a hood with an outlet that is arranged so as to cover the brush. The outlet of this hood may be connected to the abovementioned dust collector. In this case, the hood may be supported on a supporting frame that supports the brush, with the aid of pins in such a fashion as to swing back and forth in the grinding direction. The lower end of the hood may be provided with a sealing member for bringing the underside of the hood into close contact with the surface of the workpiece. The use of the brush unit enables substantially thorough removal of chips, since its tubular brush can remove fine chips which are left during grinding operation, sticking to the surface of the workpiece because of oil and the like.

In the invention, the main body frame for supporting the grinding tool may be supported by an arm of a robot or alternatively supported on a carriage that travels along the surface of the workpiece to be ground.

Brief Explanation of the Drawings Figure 1 is a side elevation of a grinding machine according to one embodiment of the invention.

Figure 2 is a top view of the grinding machine according to the embodiment of the invention.

Figure 3 is a rear elevation of the grinding machine according to the embodiment of the invention.

Figure 4 illustrates the detailed construction of a hood.

Figure 4(a) is a top view; Figure 4(b) is a sectional view taken along line B-B of Figure 4(a); and Figure (c) is a sectional view taken along line C-C of Figure 4(a).

Figure 5 is a perspective view of a brush.

Best Mode for Carrying out the Invention Referring now to the drawings, a preferred embodiment of a grinding machine according to the invention will be described below.

Figure 1 shows a side elevation of the grinding machine according to the embodiment of the invention, Figure 2 shows its top view and Figure 3 shows its rear elevation (partially broken).

In the grinding machine 1 ofthis embodiment, a main body frame (holder) 2 is supported by an arm of a robot (not shown) or on a carriage (not shown) through an attachment board 3 so as to slightly incline backward with respect to a vertical axis. The car riage travels in the direction of arrow A (see Figure 1) along the surface of a workpiece W. Provided on the front face of the main body frame 2 is a sliding plate 4 that is slidable up and down along the main body frame 2. A grinder 6 is attached to the front face of this sliding plate 4 through an attachment board 5.

The grinder 6 has a disk-like grinding wheel 6a that is located under the rear part of the main body of the grinder 6, with its wheel center being slightly backwardly inclined with respect to a vertical axis. In this way, the grinding wheel 6a is supported and inclined such that the wheel face is inclined backwardly toward the grinding face of the workpiece W, which enables the rear part of the wheel face to grind the grinding face.

An air cylinder 7 consisting of a bellofram cylinder is attached to the front of the main body frame 2, and the tip of a cylinder rod 7a of the air cylinder 7 is secured to the front of the attachment board 5 by means of a fixture. Disposed ahead of the air cylinder 7 is a pressure control valve 8 that is connected to the cylinder chamber through a pipe line. The pressure control valve 8 is actuated to allow air present in the cylinder chamber of the air cylinder 7 to be released to the atmosphere when the air pressure of the cylinder chamber exceeds a specified level. In this structure, a pressure exerted from the workpiece W on the grinding wheel 6a of the grinder 6 acts as a lift force on the cylinder rod 7a through the attachment board 5. By keeping a balance between the lift force and the air pressure ofthe cylinder chamber, the pressure of the grinding wheel 6a applied to the workpiece W can be kept to a constant value. When the lift force exceeds the constant value, the air pressure of the cylinder chamber is released to the atmosphere by the pressure control valve 8 so that no pressure exceeding the specified level is applied to the grinding wheel 6a. Reference numeral 9 designates a pressure gauge used for visual confirmation of a set pressure (relief pressure) for the pressure control valve 8.

The grinding wheel 6a of the grinder 6 is covered with a hood 1() for preventing scattering of chips. B) means of four hanging rods 12, the hood 10 is hung from a support 11 that is in turn suspended from the main body frame 2. Each of the hanging rods 12 is supported by the support 11 in a vertically slidable fashion so that the hood 10 is movable up and down relative to the support 11.

Spring coils 13 respectively wound around these hanging rods 12 constantly urge the hood 10 downward so that the hood 10 can follow the surface of the workpiece W. It should be noted that, in the condition where grinding is not performed, that is, the condition where no external force is exerted on the hood 10 from the workpiece W the underside of the hood 10 is located in a position (shown in Figure 1) lower than the lower end of the grinding wheel 6a.

The construction of the hood 10 is shown in detail in Figure 4.

As seen from Figure 4, the hood 10 is substantially square in a top view and includes, at its center, an insertion opening 10a through which the grinder 6 can be partially inserted. The hood 10 also has an outlet lOb which is formed on the front side with respect to the grinding direction. Connected to the outlet 1b is an induction pipe (ejector) 14 connected to a dust collector (not shown). The hood 10 has a profile in which its underside is inclined with the front part being higher in level than the rear part in order that the underside can be constantly kept in close contact with the surface of the workpiece W. Inside the hood 10 is formed a dust chamber 10d.

The section of this dust chamber 10d, which is parallel with the wheel face of the grinder 6, is substantially square (or rectangular).

In this embodiment, there is provided an air injection unit 15 on the front face of the hood 10. The air injection unit 15 has a jet 15a formed in the front part thereof and ejects air from the jet 15a forwardly, diagonally down to the surface of the workpiece W, thereby blowing out oil that adheres to the surface of the workpiece W.

As described earlier, the hood 10 ofthis embodiment is resiliently supported by the main body frame 2 through the coil springs 13. independently of the grinder 6. Thus, after lowering the main body frame 2 from the state as shown in Figure 1 where the underside of the hood 10 is in close contact with the surface of the workpiece W and the grinding wheel 6a is above the surface of the workpiece W, the surface of the workpiece W can be ground bx the grinding wheel 6a that has been also lowered while the hood 10 being kept at all times in close contact with the surface of the workpiece W. In addition, since the pressure of the grinder 6 working on the workpiece W is controlled by the air cylinder 7, chips present in the hood 1() can be pumped up by the induction pipe 14 after completion of grinding by increasing the pressure of the air cylinder 7 upon completion of grinding to the extent to which onls the grinder 6 will be lifted, so that scattering of chips which may occur when lifting the main body frame 2 upon completion of grinding can be avoided. In this way, chips generated during grinding can be positively entrapped in the hood 10 to ensure prevention of an escape of chips outside the hood 10.

Chips produced by the rotation of the grinding wheel 6a during grinding operation once strike against the side walls of the dust chamber i()d having a substanti llr square section so that the kinetic energy of the chips is absorbed by the side walls. Thereafter, the chips are guided into the outlet 1b and positively sucked by the dust collector through the outlet 1b and the induction pipe 14.

Now, there is explained a brush unit 16 that is disposed behind the grinder 6 with respect to the grinding direction.

Mounted on the back of the main body frame 2 is a slide guide 17. The brush unit 16 is arranged so as to be slidable vertically along this slide guide 17. The brush unit 16 comprises: a supporting frame 18; a motor 19 mounted on the supporting frame 18; a tubular brush 21 (see Figure 5) rotatable in the direction of arrow D shown in Figure 1 by actuation ofthe motor 19 through a gear transmission mechanism 20; and a hood 22 attached to the supporting frame 18 so as to cover the brush 21.

On the right of the supporting frame 18, there is secured an arm plate 23 projecting toward the side of the main body frame 2. The arm plate 23 is resiliently supported by the main body frame 2 through a coil spring 24 inserted in the main body frame 2. With this arrangement, when pressure is applied to the brush 21 from the surface of the workpiece W, the pressure is absorbed by the coil spring 24.

The hood 22 has a substantially semi-cylindrical shape the underside of which is open and supported at both central sides by the supporting frame 18 with the aid of pins. Specifically, the hood 22 is able to swing back and forth within a specified angular range, by virtue of the engagement of four pins 25 provided by two on the right and left of the supporting frame 18 with elongated holes 26 that are formed on the hood 22 correspondingly with the pins 25.

The forward swing of the hood 22 exceeding a specified angle is restricted by a contact between a stopper 27 attached to the front part of the hood 22 and the top face of the hood 10 for the grinder 6.

The hood 22 has an outlet 28 at the front part thereof, the outlet 28 being connected through an induction pipe 29 to the dust collec tor that is common to the induction pipe 29 and the induction pipe 14 provided for the grinder 6. A sealing member 30 is attached throughout the periphery of the lower end of the hood 22 and the use of the sealing member 30 ensures to establish a close contact between the lower end of the hood 22 and the surface of the workpiece W.

In the grinding machine 1 having the structure described above, the attachment board 3, and as a result, the grinding wheel 6a of the grinder 6 are lowered so that the surface of the workpiece W can be ground b5 the rear part of the grinding wheel 6a which is supported so as to incline relative to the surface of the workpiece W. During the grinding operation, the hood 10 is relative) moved upward against the biasing force of the coil springs 13 so that grinding is performed while the underside of the hood 10 being always kept in close contact with the surface of the workpiece W. This ensures that chips of comparatively large size generated during grinding are collected within the dust chamber 10d of the hood 10 to be sucked by the dust collector through the outlet 10b and the induction pipe 14. Additionally, since the pressure of the grinder 6 working on the workpiece W is controlled by the air cylinder 7, chips present in the hood l() can be pumped up bs the induction pipe 14 after comple tion of grinding b) increasing the pressure of the air cylinder 7 upon completion of grinding to the extent to which only the grinder 6 can be lifted, thereb) avoiding scattering of chips which may occur when lifting the main body frame 2 upon completion of grinding.

Chips remaining without being collected by the hood 10, that is, ùr exalllple fine chips sticking to the surface of the workpiece W because of oil can be completed) removed by the rotating brush 21 after the brush unit 16 has passed through the area being ground by the grinder 6. The fine chips thus removed are entrapped in the hood 22 that covers over the brush 21 and sucked br the dust collector through the outlet 28 and the induction pipe 29. At that time, the supporting frame 18 for supporting the brush 21 is resiliently supported on the main body frame 2 with the aid of the coil spring 24 and the hood 22 is supported on the supporting frame 18 so as to swing back and forth. This allows the brush 21 to follow the sur Rice of the zorkpiece W independently of the grinder 6 and enables the removal of chips while the underside of the hood 22 for the brush 21 being always kept in close contact with the surface of the workpiece W.

The grinding machine 1 of this embodiment may be arranged such that the attachment board 3 is supported on the arm of a robot as mentioned earlier and grinding of the workpiece W is performed as desired by moving the arm. Alternatively the attachment board 3 ma5 be supported on a carriage or traveling head that travels along guide rails so that grinding of the workpiece W placed under the guide rails can be carried out. In this case, it is preferable to lay the guide rails so as to be movable in a direction perpendicular to the lengthwise direction of the guide rails, because this enables it to position the grinder 6 freely relative to the surface of the sheet-like workpiece W in the directions of its X and Y axes.

Claims

Claillls

1. A grinding machine which comprises a grinding tool supported b) a main bod) frame, a hood with an outlet arranged so as to cover a rotating tool section of the grinding tool, and a dust collector connected to the outlet of the hood, characterized in that said hood is supported by the main bod5 frame through resilient supporting means, independently of the grinding tool.

2. A grinding machine according to Claim 1, wherein said grinding tool is supported bv said main body frame through press itig force regulating means for regulating a pressing force working on the surface of a workpiece to be ground.

3. A grinding machine according to Claim 1, wherein said grinding tool consists of a grinder having a disk-like grindstone and is supported such that the wheel face of the grinder is inclined backwardly toward the grinding face of a workpiece.

4. A grinding machine according to Claim 3, wherein said hood includes a dust chamber formed therein and having a substan tally rectangular section, the section extending parallel with the wheel face of the grinder.

5. A grinding machine according to Claim 4, wherein the section of said dust chamber, which is perpendicular to the wheel face, has a substantiallx trapezoidal shape tapered so as to be widened forward.

6. A grinding machine according to any one of Claims 1 to 5, which further includes a brush unit for cleaning the surface of the workpiece after completion of grinding operation performed by the grinding tool, the brush unit being located behind the grinding tool with respect to a grinding direction.

7. A grinding machine according to Claim 6, wherein said brush unit is supported by the main body frame through resilient supporting means, being independent of the grinding tool.

8. A grinding machine according to Claim 6, wherein said brush unit comprises a substantially tubular brush that is rotatable about a horizontal axis perpendicular to the grinding direction and a hood with an outlet provided so as to cover the brush, said outlet of the hood being connected to said dust collector.

9. A grinding machine according to Claim 8, wherein said hood is supported by a supporting frame for supporting the brush with the aid of pins such as to swing back and forth in the grinding direction.

10. A grinding machine according to Claim 8, wherein said hood is provided with a sealing member at its lower end, for bringing the underside of the hood into close contact with the surface of the workpiece.

11. A grinding machine according to Claim 1, wherein said main body frame is supported by an arm of a robot.

12. A grinding machine according to Claim 1, wherein said main body frame is supported by a carriage that travels along the surface of the workpiece to be ground.