This application claims priority to European Application No. 13152843.2, filed Jan. 28, 2013, which is incorporated by reference herein in its entirety.
Field
The invention relates to the field of automation and, particularly to a machine for replacing disc tools.
Description of the Related Art
Disc tools such as grinding discs lose their grinding surface rapidly in automated applications, e.g. when the grinding discs are used by an automated robot or another automated machine capable of using various disc tools. Automated solutions in replacing the disc tools are needed to improve efficiency.
According to an aspect of the invention, there is provided a method comprising in a disc tool replacement machine: determining that a tool holder of an automated machine working with disc tools is in a replacement area in the disc tool replacement machine; unfastening a fixing member of the tool holder by applying an unfastening force to the fixing member, wherein the fixing member fixes a disc tool to a backing plate of the tool holder through a through hole at a centre of the disc tool; removing the disc tool from the tool holder after said unfastening; inserting a new disc tool to the tool holder; fastening the fixing member of the tool holder by applying a fastening force to the fixing member, thus fixing the disc tool to the backing plate of the tool holder through the through hole.
According to another aspect of the invention, there is provided a disc tool replacement machine comprising: a controller configured to determine that a tool holder of an automated machine working with disc tools is in a replacement area in the disc tool replacement machine; a fastening tool configured to unfasten a fixing member of the tool holder by applying an unfastening force to the fixing member, wherein the fixing member fixes a disc tool to a backing plate of the tool holder through a through hole at a centre of the disc tool; a replacement system configured to remove the disc tool from the tool holder after said unfastening and insert a new disc tool to the tool holder, wherein the fastening tool is further configured to fasten, after the new disc tool has been inserted to the tool holder, the fixing member of the tool holder by applying a fastening force to the fixing member, thus fixing the disc tool to the backing plate of the tool holder through the through hole.
According to yet another aspect of the invention, there is provided a computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into the computer, cause the computer to execute a computer process comprising: determining that a tool holder of an automated machine working with disc tools is in a replacement area in a disc tool replacement machine; causing unfastening of a fixing member of the tool holder by causing application of an unfastening force to the fixing member, wherein the fixing member fixes a disc tool to a backing plate of the tool holder through a through hole at a centre of the disc tool; causing removal of the disc tool from the tool holder after said unfastening; causing insertion of a new disc tool to the tool holder; causing fastening of the fixing member of the tool holder by causing application of a fastening force to the fixing member, thus fixing the disc tool to the backing plate of the tool holder through the through hole.
Embodiments are defined in the dependent claims.
Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which
The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words “comprising” and “including” should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may contain also features/structures that have not been specifically mentioned.
Referring to
The frame of the disc tool replacement area may comprise multiple levels. The fixture 106 and the guiding track 100 may be provided on the topmost level and, below that, a disc tool replacement level 110 may be provided. The disc tool replacement level 110 may comprise storage areas for new disc tools and used disc tools and tool replacement machinery. The gripper(s) 102, 108 may thus grip the tool holder 104 such that the disc tool faces downwards towards the disc tool replacement level 110.
Below the disc tool replacement level 110, a compartment may be provided for a computer or controller 103 controlling the operation of the disc tool replacement machine. The computer may comprise connectors and associated communication links to control the operation of various motors in the disc tool replacement machine and to communicate with the robot, as described in greater detail below.
The computer may keep track on which one of the grippers holds the tool holder and which one does not. This may be realized by communicating with the robot and controlling the gripping mechanism of the grippers 102, 108. Upon connecting the tool holder to the robot's arm, the robot may output an instruction to the computer to release the grip from that tool holder. Similarly, when the robot brings a tool holder to the disc tool replacement machine for the replacement of a worn disc tool, the robot may position the tool holder between pincers of the gripper and instruct the computer to grip the tool holder. Thereafter, the robot may release the tool holder. Upon detecting that the robot has replaced the tool holder, the computer may determine which one of the grippers contains a tool holder having a disc tool that needs to be replaced. The computer may then determine the correct motion trajectory for the fixture such that the correct tool holder is brought to a correct position for the disc tool replacement. The correct position may be above the through hole 204 to enable the disc tool replacement from below the tool holder.
With respect to the disc tool itself, the disc tool may be a grinding disc used for grinding a surface of an object, a polishing disc used for polishing a surface, or a cutter disc used for cutting, for example. The cutter disc may have a saw-toothed edge or an abrasive edge. The disc tool may have a through hole in the middle of the disc tool for attaching the disc tool to the tool holder. Typically, the fixing may be realized via the through hole by a central nut and bolt. The tool holder may comprise a backing plate to support the disc tool and a fixing member, e.g. a centre bolt, at the centre of the backing plate for fixing the disc tool. A counterpart fixing member, e.g. a centre nut, may comprise a flange that presses the disc tool to the backing plate when the counterpart fixing member is fixed to the fixing member of the tool holder. The disc tool may comprise a base layer which may comprise a fiberglass, resin fibre, heavy paper, or metal layer. In some embodiments, the disc tool further comprises a tool layer defining the function of the disc tool. The tool layer may comprise an abrasive surface to realize the grinding or cutting function, or some soft material for the polishing. In the embodiment where the disc tool is a saw, the tool may be provided in the base layer, e.g. on the edge of the base layer.
A fastening/unfastening tool 422 is provided in alignment with the through hole 204 over which the tool holder 104 is placed for the replacement of the disc tool. The fastening/unfastening tool 422 may comprise a tool tip 420 matched in form to the fixing member of the tool holder such that they form counterparts for fastening and unfastening the fixing member. The fastening/unfastening tool may further comprise a flange 418 around the tool tip to provide a supporting plane for the disc tool when the fixing member is unfastened and the disc tool is detached from the tool holder. The fastening/unfastening tool 422 may comprise a motor providing a rotary motion that rotates the tool tip 420 and, as a consequence, unscrews the fixing tool from the tool holder 104 when removing the used disc tool and again screws the fixing tool to the tool holder when a new disc tool has been positioned on the flange and the fixing member has been brought into contact with the tool holder. The motor may be an electric motor, a pneumatic motor, or a hydraulic motor.
In order to move the tool tip and the disc tool detached from the tool holder with respect to the tool holder, the fastening/unfastening tool may comprise a second motor that provides the tool tip with linear motion. The linear motion may comprise linear up/down motion, but equally one could envisage embodiments where the linear motion comprises lateral motion along the supporting plate 200. The second motor may comprise a linear actuator realized by an electric motor, pneumatic motor, or a hydraulic motor.
The disc tool replacement machine may comprise on the disc tool replacement level a replacement member to move the disc tools between the fastening/unfastening tool 420 and the storage area(s) 402 to 408. The replacement member may comprise at least one contacting member 416 to grip the disc tool and an actuator to move the contacting member 416 and the disc tool between the tool tip 420 and the storage area(s) 402 to 408. The actuator may comprise a linear actuator to provide linear motion, e.g. an up/down motion, and a rotary actuator, e.g. a servo motor, to provide a rotary motion. The linear motion may be needed to place the used discs to the spindles of the storage areas and to raise a new disc tool from the spindle. The linear motion may also be needed to position the disc tool to the tool tip 420. The rotary motion may be used to provide lateral motion to move the disc tools along the supporting plate 200 between the storage area 402 to 408 and the tool tip 420. Lateral linear motion may be combined with the lateral rotary motion in some embodiments.
The replacement member may comprise an arm 414 and at least one vacuum cup 416 provided along the arm 414. The vacuum cup(s) 416 may be used as the contacting member to grip the disc tools when the linear actuator presses the vacuum cup(s) into contact with the disc tool. The vacuum cup(s) may comprise an air duct between interior and exterior of the vacuum cups to remove the air from the interior of the vacuum cup 416 when the vacuum cup 416 grips the disc tool and to blow the air to the interior of the vacuum cup when the grip needs to be released.
Let us now describe the operation of the disc tool replacement with reference to
After the new disc tool is attached to the tool holder 104, the tool holder may be moved along the guiding track 100 to the robot's working area to wait for the robot to change the tool holder.
As mentioned above, the disc tool replacement is applicable to tool holders that may be detached from the robot's arm and to tool holders that are fixed to the robot's arm during the disc replacement.
The operation of the disc tool replacement machine may be understood as an automated process for replacing the disc tools. The process is controlled by the computer executing a computer program comprising program code instructions defining the control of the process.
Let us now describe, with reference to
In block 602, the fixing member of the tool holder is unfastened by applying an unfastening force to the fixing member. Upon detecting the tool holder in the replacement area, the computer may output one or more control signals to the fastening/unfastening tool to contact the fixing member and to apply the unfastening force. As described above, the fixing member fixes the disc tool to the backing plate of the tool holder through the through hole at the centre of the disc tool. In block 604, the disc tool is removed from the tool holder after said unfastening. This may be realized by separating the fastening/unfastening tool from the tool holder and gripping and removing the disc tool from the top of the fastening/unfastening tool. It should, however, be appreciated that in other embodiments the disc tool may be gripped while it is in contact with the backing plate. An essential feature is that the disc tool is removed automatically and replaced with a new one. The computer may control the removal of the used disc tool by outputting a control signal to the fastening/unfastening tool to separate from the tool holder, and by outputting a control signal to the replacement member to remove the used disc tool after the fastening/unfastening tool is separated from the tool holder. A new disc tool is placed to the backing plate in block 604. This may be realized by placing the new disc tool on top of the tool tip of the fastening/unfastening tool and moving the tool tip to face the tool holder. With respect to the computer, upon placing the new disc tool to an appropriate location and bringing the fixing member into contact with the tool holder, the computer may control the fastening/unfastening tool to apply a fastening force to the tool tip, thus fixing the fixing member to the tool holder and the disc tool to the backing plate (block 606).
An advantage of the automated process is that reloading new disc tools and removing the used ones may be carried out without interfering the robot's work process. Additionally, the number of required tool holders is low, and the operator's workload is reduced with respect to solutions where the operator manually changes the disc tools.
In the embodiment where the fixing member is a centre nut locking member 411, said unfastening the fixing member may comprise unscrewing the fixing member off from the tool holder, and the fastening may comprise screwing the fixing member to the tool holder. The fastening and unfastening forces are thus provided by rotary motion of the fastening/unfastening tool. In an embodiment, the tool tip of the fastening/unfastening tool is provided with a translational motion to bring the tool tip into contact with and to detach the tool tip from the counterpart of the fixing member.
In an embodiment, at least one gripper is arranged to move between the replacement area and a second area a determined distance away from the replacement area, e.g. the robot's working area, to grip the tool holder in the second area, deliver the tool holder to the replacement area for the replacement of the disc tool, deliver tool holder back to the second area, and release the grip from the tool holder in the second area.
In an embodiment, the gripper is arranged to grip the tool holder such that the grip prevents rotation of the disc tool when fastening and unfastening the fixing member. Let us bear in mind that the tool holder is also arranged to deliver a rotary force from the robot's motor to the disc tool such that the disc tool rotates to affect the grinding, cutting, or polishing. Thus, the tool holder may comprise a first part that rotates while the backing plate remains still and a second part that is fixed with respect to the backing plate. Gripping the tool holder from the first part may cause the rotation of the backing plate and the tool holder when attempting to unfasten the fixing member. The tool holder may thus grip the tool holder from the second part called a gripping part which is fixed with respect to the backing plate and the disc tool. A surface of the gripping part and a gripping surface of the gripper(s) may be formed as counterparts such that the gripper locks to the gripping part. In an embodiment, recessions are provided in the gripping part and matching protrusions are provided in the gripping surface of the gripper. When the protrusions enter the recessions, the gripper locks its grip to the gripping part, thus preventing the rotation of the backing plate during the fastening and unfastening of the fixing member. Naturally, other means for locking the grip may be provided.
The processes or methods described in
According to an aspect, the disc tool replacement machine is provided. The disc tool replacement machine may comprise the computer configured to determine that the tool holder is in the replacement area in the disc tool replacement machine and to control the disc tool replacement. The disc tool replacement machine further comprises the fastening/unfastening tool configured to unfasten the fixing member of the tool holder by applying the unfastening force to the fixing member. The disc tool replacement machine further comprises a replacement member configured to remove the disc tool after said unfastening and to inserting a new disc tool to be attached to the tool holder. The fastening/unfastening tool then fastens the fixing member of the tool holder by applying the fastening force to the fixing member, thus fixing the disc tool to the backing plate of the tool holder through the through hole.
While this description provides a detailed description of some of the embodiments of the invention, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the described embodiments. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
Number | Date | Country | Kind |
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13152843 | Jan 2013 | EP | regional |
Number | Name | Date | Kind |
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4780951 | Beyer | Nov 1988 | A |
6030326 | Azuma | Feb 2000 | A |
Number | Date | Country |
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3246168 | Jul 1983 | DE |
3326292 | Jan 1985 | DE |
3620047 | Jan 1987 | DE |
10 2007 004 633 | Aug 2007 | DE |
2 067 570 | Jun 2009 | EP |
2 823 142 | Oct 2002 | FR |
07-017443 | Mar 1995 | JP |
2007-229843 | Sep 2007 | JP |
Entry |
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Machine Translation JP 07-017443-U, which JP '443 was published Mar. 1995. |
Machine Translation of JP 2007-229843, which JP '843 was published Sep. 2007. |
European Office Action, EP 13 152 843.2, dated Sep. 16, 2015, 5 pages. |
European Search Report, Application No. EP 13 15 2843, Apr. 30, 2013. |
Number | Date | Country | |
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20140243176 A1 | Aug 2014 | US |