Tool changing – Including machine tool or component – Rotary spindle machine tool
Reexamination Certificate
2000-06-13
2001-12-25
Briggs, William (Department: 3722)
Tool changing
Including machine tool or component
Rotary spindle machine tool
C483S013000, C483S901000, C901S041000
Reexamination Certificate
active
06332861
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automatic bladed tool changer and, more particularly, to an automatic bladed tool changer for a bladed tool mounted to the distal end of a robot arm.
2. Description of the Prior Art
To automatically change a bladed tool for machining such as deburring mounted to a robot, one rotary tool and one automatic tool changer (ATC) are conventionally installed for each bladed tool to change the bladed tool itself. In this case, it is necessary to provide protection against dust for an ATC mounting/demounting face on a tool table.
Also, as disclosed in Japanese Patent Application Laid-Open No. 8-57730, a technique has been well known in which a tightening and loosening mechanism such as a nut runner is provided on the side of peripheral equipment other than a robot to automatically change a bladed tool.
Further, when a bladed tool is mounted to or demounted from the rotary tool, in order to align the rotational position of the rotary tool with the phase of the bladed tool, the rotational angle of the rotary tool is detected by using an angle detector or the like, and the rotating shaft of the rotary tool is fixed so as to agree with the phase of the bladed tool. Thereafter, the bladed tool is mounted to or demounted from the rotary tool. Further, by additionally machining the bladed tool itself or by reconstructing it by, for example, mounting an adapter thereon, the mounting and demounting of the bladed tool to and from the rotary tool is performed easily.
Another method is used in which the operator changes a bladed tool by using a special-purpose change jig.
In the above-described conventional bladed tool change, when an ATC is used, rotary tools and ATCs corresponding to the number of kinds of tools are needed. Therefore, the number of bladed tools used increases, which leads to an increase in cost. Also, when an ATC is used, an ATC bed also requires a complicated mechanism such as measures against dust and equipment for mounting and demounting, which also causes an increase in price. Further, the installation space is increased, so that the number of kinds of bladed tools is limited. Besides, in some cases, the work must be distributed to a plurality of processes because of the limitation of the work area of robot.
When peripheral equipment dedicated to bladed tool change is installed, there arises a problem in that the price increases accordingly, and a large installation space is needed.
Further, when an angle detector or the like is used to mount and demount a bladed tool to and from the rotary tool, the price undesirably increases accordingly.
Also, the method in which the mounting and demounting of a bladed tool is made easy by the reconstruction of a commercially sold rotary tool, the additional machining of a bladed tool, the addition of a special-purpose adapter, etc. has a problem in that the price is increased by the reconstruction of equipment.
In a bladed tool changing work performed by the operator, failed or insufficient tightening of bladed tool, variations in bladed tool extension, etc. occur, which causes the occurrence of defective machining due to the bladed tool. In particular, when the bladed tool changing work is performed by the operator, a special-purpose jig for controlling the bladed tool extension is needed, which also increases the cost, and prevents the work from being made automatic.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described problems, and accordingly an object thereof is to provide an automatic bladed tool changer capable of automatically changing a bladed tool on a rotary tool attached to the distal end of a robot arm at a low cost.
The automatic bladed tool changer in accordance with the present invention automatically mounts and demounts a bladed tool to and from the rotary tool having a collet chuck attached to a flange at the distal end of the robot arm.
In a first mode of the automatic bladed tool changer in accordance with the present invention, a robot is controlled according to a program by control means so as to open and close the collet chuck to mount and demount a bladed tool to and from the rotary tool.
In a second mode of the automatic bladed tool changer in accordance with the present invention, rotating shaft locking means for fixing a rotating shaft of the rotary tool is attached to the flange, and the robot and the rotating shaft locking means are operated according to a program by control means so that a chuck nut is fixed by chuck nut fixing means provided on bladed tool storage means in which the bladed tool is stored and the rotating shaft of the rotary tool is fixed by the rotating shaft locking means, so that the chuck nut and the rotating shaft are rotated relatively to open and close the collet chuck, whereby the bladed tool is mounted and demounted to and from the rotary tool.
The automatic bladed tool changer according to the first or second mode can adopt the following embodiments.
The control means has means for performing bladed tool tightening of the collet chuck by the robot operation using a predetermined torque limit value set on the robot.
The control means has means for estimating a disturbance torque of a tightening shaft by using an observer when the bladed tool tightening of the collet chuck is performed by the robot operation and for judging that the tightening is completed when the estimated value exceeds a predetermined threshold value.
The rotating shaft locking means is provided with a cylinder for reciprocating a stopper for engaging with the rotating shaft and locking the same, the stopper is pressed against the rotating shaft by driving the cylinder repeatedly, the rotating shaft is rotated slightly and is brought to a rotation phase in which the stopper engages with the rotating shaft and is fixed, and the stroke of the cylinder is monitored to detect that the rotating shaft is fixed to the stopper, by which the rotating shaft is fixed at this position as the completion of locking.
The control means sets a bladed tool extension to a predetermined value by pressing the bladed tool on a bladed tool positioning stopper by operating the robot.
The control means stores in storage means a holding position or a position returned from the holding position through a predetermined rotational angle after the bladed tool is tightened and held by the collet chuck by the robot operation, and uses the stored position as the start position for bladed tool removing operation when the bladed tool is removed from the collet chuck.
The control means is a robot controller.
According to the present invention, a bladed tool can be mounted and demounted easily to and from the rotary tool attached to the robot.
In particular, since the robot controller can also be used as the control means, the addition of special hardware is not needed, so that the automatic bladed tool changer can be configured at a low cost.
Moreover, even when bladed tools to be used are increased, the bladed tool storage apparatus has only to be installed additionally, so that the installation space can be saved.
Since the tightening torque of bladed tool can be set and controlled and the bladed tool extension can be controlled by a robot, time and labor for manual control and a special-purpose jig are unnecessary, so that the cost can be reduced and the quality of machining work (for example, deburring work) using the robot and rotary tool can be upgraded.
Since a commercially sold bladed tool and rotary tool can be used, additional machining of the bladed tool or rotary tool is unnecessary, which leads to a reduction in cost. Further, since only one rotary tool is needed for a plurality of bladed tools, a plurality of rotary tools and ATCs that have been needed conventionally are unnecessary, which accordingly reduces the price. Also, since the ATC is not needed, a mechanism for dustproof measures for a tool table is unnecessary, so that the space and cost can be decreased.
REFERENCES:
patent: 3521525 (19
Oda Masaru
Otsuka Kazuhisa
Takahashi Kenji
Briggs William
Fanuc Ltd.
Staas & Halsey , LLP
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