Abstract:
The invention relates to an exchangeable tool having a tool body with a receiving end for holding the tool in a receiving structure, wherein a connector is arranged in the tool body for providing a substantially non-rotatable connection with a manipulator for manipulating the tool into and out from the receiving structure,
       to a combination of such tool with a manipulator for manipulating the tool into and out from a receiving structure,   and to a method for manipulating such tool into and out from a receiving structure.

Description:
BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The invention relates to an exchangeable tool having a tool body with a receiving end for holding the tool in a receiving structure. 
     2) Description of the Prior Art 
     Such a tool is, for example, known from the European Patent Publication No. 0 494 714. 
     SUMMARY OF THE INVENTION 
     When automating the exchange of tools, a manipulator, such as a robot arm is used to take the tools and transport them from the machine, in which the tools are used, to a storage, and vice versa. When manipulating the tools with a manipulator it is beneficial that the tools will not rotate in relation to the manipulator. This is necessary to ensure the control logic to know the exact position of the tool at the end of the manipulator arm, such that the tool can be reliably inserted into the respective machine or into the storage. If the tool would be able to shift or rotate uncontrolled, the manipulator would need to re-orientate the tool before inserting the tool in for example a receiving structure. 
     When using tools with different sizes, shapes and/or dimensions in one machine, it is beneficial to be able to hold the tool in a uniform way, as otherwise the manipulator has to change grippers in order to be able to exchange the different tools. For example the manipulator would need a first gripper to exchange slim tools, while a second gripper is necessary to exchange wide tools. This would have an adverse effect on the productive time of the machine. It is thus desirable to have an uniform way of holding the tool which is independent from the shape and dimensions of the tool. 
     A further requirement is that the gripper must hold the tool firmly. When the tool is subjected to substantial accelerations, in combination with the weight, the forces will be substantial. A connection between the gripper and the tool must withstand these forces. 
     It is therefor an object of the invention to provide a way of holding tools in a uniform way and preventing rotation of the tool in relation to the manipulator. 
     This object is achieved by an exchangeable tool according to the preamble, wherein connecting means are arranged in a tool body for providing a substantially non-rotatable connection with a manipulator for manipulating the tool into and out of the receiving structure. 
     With such a connecting means, the connection point is standardized and a connection of the tool with the manipulator is no longer dependent from the geometry of the tool. Due to the substantially non-rotatable connection, the orientation of the tool in relation to the manipulator is always known. Even if the manipulator has a rotatable joint, the orientation in the connection of tool and manipulator is fixed. As the connection is no longer dependent from the geometry of the tool, the connection means can be arranged at any suitable part of the tool and even on opposite sides, such that the manipulator can approach the tool from two sides. 
     In an embodiment according to the invention the connecting means are arranged such that force transfer between the tool and the manipulator takes substantially place inside the tool body. With this embodiment the outside geometry of the tool is not important for connecting the tool to a manipulator. With the connecting means arranged in the tool body force transfer from the manipulator to the tool and vice versa takes place directly into the body and not through an outer surface of the tool. This is advantageous, as the shape of outer surfaces may differ by the type of the tool. 
     In another embodiment of the tool according to the invention the connecting means are arranged such that the substantially non-rotatable connection is achieved by connecting the manipulator from only one side to the tool. By connecting the manipulator from only one side to the tool, the shape of the opposite side of the tool is irrelevant for providing the connection. 
     In a preferred embodiment of the tool according to the invention, the connecting means comprise a cavity with an insertion axis along which a manipulator can be inserted and wherein the cavity is non-rotation symmetrical with respect to the insertion axis. It will be obvious that an inverted solution with the cavity in the manipulator and a protrusion arranged on the tool will provide a similar solution with similar advantages. 
     Preferably the cavity is cylindrical with at least a rib extending through the cavity. This rib prevents the possible rotation between the tool and the manipulator. 
     In another preferred embodiment two parallel ribs are arranged at the mouth opening of the cavity. These two ribs provide a further locking of the angular position of the tool in relation to the manipulator and prevents accordingly rotation. 
     In yet another embodiment of the tool according to the invention the cavity has a non-circular cross-section perpendicular to the insertion axis, the cross-section being for example square or elliptical. This enables insertion of a corresponding manipulator into the tool, and prevents rotation of the tool relative to the manipulator. 
     In another embodiment of the tool according to the invention, the connecting means provide a uniform, substantially non-rotatable connection and provide means for an additional function. With the uniform connection the shape of the tool is irrelevant for connection with the manipulator. In addition the connection means provide means for an additional function. 
     Preferably, with the tool according to the invention the means for an additional function comprise at least one terminal for additional functions, such as transfer of signals or activation of a mechanism. With a connection electrical signals can for example be exchanged between the tool and the manipulator. For example the electrical signals are used to read out a memory arranged in the tool, or the signal is used to activate an actuator present in the tool, for example to actuate a safety device. This at least one terminal for additional functions can also be used to transfer a mechanical signal such that a mechanical switch or mechanism is put from a first state into a second state. Furthermore, the terminal can be used to exchange light signals. 
     In another preferred embodiment the connecting means are arranged at a standardized distance from the receiving end. This enables the manipulator to grab a tool, without exact knowledge of the type of tool present in the receiving structure. 
     The invention further relates to a combination of a tool according to the invention and a manipulator for manipulating the tool into and out from a receiving structure, wherein the manipulator comprises connecting means for connecting to the connecting means of the tool. 
     In a preferred embodiment of the combination according to the invention the connecting means of the manipulator are adapted to the non-rotation symmetrical cavity of the tool. 
     In another preferred embodiment of the combination according to the invention the manipulator has a connecting end having a cross-section perpendicular to the insertion direction, which is substantially equal to the mouth opening of the cavity of the tool, and wherein the manipulator comprises at least one retractable cam extendible from a surface of the connecting end to lock the manipulator to the tool. This at least one cam will extend behind the linear rib present in the cavity, such that the tool is locked onto the manipulator and the tool cannot be separated from the manipulator, without retracting the cam. 
     In a further preferred embodiment, the connecting end has at least one surface coacting with an inner surface of the cavity to provide a non-rotatable connection. 
     In yet another embodiment of the combination according to the invention, the combination comprises detecting means for detection of the connection of the manipulator and the tool. This will provide security for the control of the manipulator, that a tool is indeed held by the manipulator. 
     Preferably, the detecting means comprise a switch. 
     In yet another embodiment of the combination according to the invention, the connecting means of the tool comprise a bush having a substantially non-rotation symmetrical cavity and the connecting means of the manipulator comprise a connecting end adapted to and insertable into the cavity, wherein the connecting end comprises an retractable cam extendable into an opening into the cavity wall of the bush. Preferably the cam is a ball. 
     This cam provides for a locking of the connecting end of the manipulator into the bush. 
     In a preferred combination of the invention the connecting end of the manipulator has a central passage in which a pusher is movable for pushing the cam out of the connecting end. By moving the pusher such that the cam is extended from the connecting end, the locking of the connecting end into the bush is established. 
     The invention also comprises a method for manipulating a tool into and out of a receiving structure comprising:
         providing a combination according to the invention;   connecting the manipulator with the tool;   removing the tool from or inserting the tool into the receiving structure.       

     In a preferred embodiment of the invention with a combination according to the invention having a retractable cam, the connection is established by inserting the connecting end of the manipulator into the cavity of the tool and extending the retractable cam to lock the manipulator to the tool. 
    
    
     
       These and other advantages of the invention will be elucidated in conjunction with the accompanying drawings. 
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  show a cross-sectional view of a first embodiment of a tool according to the invention. 
         FIGS. 2 and 3  show cross-sectional views of a second embodiment according to the invention. 
         FIG. 4  shows a third embodiment of a tool according to the invention. 
         FIG. 5  shows a rear view of the tool according to  FIG. 4 . 
         FIGS. 6 and 7  show details of the tool according to  FIG. 4 . 
         FIG. 8  shows a fourth embodiment of a tool according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A  shows a tool  1  according to the invention. This tool  1  has a receiving end  2 , which is suitable to be inserted into a receiving structure of a machine. In this receiving end  2  a safety device  3  is arranged having a safety member  4 , which protrudes into a cavity of the receiving structure and prevents the tool from falling out of the receiving structure. Only by retracting the safety member  4  into the receiving end  2 , the tool  1  can be taken out from the receiving structure. 
     The safety device  3  is urged by spring  5 . The shown position of the safety device  3  is limited by a guide  6 . In this guide  6  a manipulator  7  can be inserted to pull the safety device  3  into the receiving end  2  and to retract the safety member  4  enabling the taking out of the tool  1  from the receiving structure. 
     In the tool body  8  a bush  9  is arranged, which provides the connecting means for the second manipulator  10  of a robot arm. This bush  9  is provided with thread, such that the manipulator  10  can be screwed into the bush  9  and be tightened to provide a substantially non-rotatable connecting. It is clear that the bush  9  is arranged such in the body  8 , that the bush  9  will not rotate in the body  8 . The bush  9  can be provided with a locking rib or the bush  9  can be integral with the body  8 . 
     The bush  9  is arranged in the tool body  8  at a fixed distance d from the top of the receiving end  2 . This will facilitate the insertion of the second manipulator  10 , as then the first vertical direction is already known and only a horizontal position has to be determined. The insertion depth of the end  12  of the manipulator  10  is then determined by an end switch  13 . As soon as this end switch  13  contacts the protrusion  60  in the bushing, the control of the second manipulator  10  knows that a connection has been made between the tool  1  and the second manipulator  10 . 
     The protrusion  60  is provided with an electrical contact connected with an electrical line  62 . This electrical contact makes contact with the switch  13  which is connected to electrical line  61 , which enables also communication of data between the tool and the manipulator. 
     Then the first manipulator  7  can be inserted into the guide  6  to retract the safety device  3  into the receiving end  2  and to retract the complete tool  1  from the receiving structure. 
     Instead of using two separate manipulators  7 ,  10  these manipulators could also be integrated, such that with one manipulator the tool can be held and the safety device can be operated. 
     In  FIG. 2  a second embodiment of the invention is shown. A bush  14  is arranged in the tool body  8  and the bush  14  has a rectangular cross section. The manipulator  15  has an end  16  which is inserted into the rectangular opening of the bush  14 . This manipulator end  16  has a ball  17 , which can be urged into an opening of the bush  14 . 
     Now turning to  FIG. 3  a second part  18  of the manipulator  15  is inserted into the manipulator end  16  through a central passage. Through this movement the ball  17  is pushed into cavity in the bush  14 , locking the manipulator end  16  into the tool body  8 . 
     The manipulator  15  is furthermore provided with a channel  19  with which a hydraulic fluid or compressed air can be supplied to the channel  49  present in the tool body  8  and with which a piston  50  can be operated in order to retract the safety member  44  to a tool releasing position. 
     The tool shown in  FIGS. 2 and 3  has a top mounted safety member  44 . This safety member  44  can also be manually operated by a push button  51 . 
       FIG. 4  shows a third embodiment  20  of a tool according to the invention. This tool  20  has a tool body  21  and a receiving end  22 . The receiving end  22  comprises a safety device  23 , which can be operated by a first actuator  24 . 
     In the tool body  21  two inserts  25  are arranged, such that a second manipulator  26  can grip the tool  20  from both sides. The safety device  23  is also provided with a push button  32 , such that the tool can always be manually operated. Such a push button could also be provided in the other embodiments described. 
     As shown in  FIG. 5  the inserts  25  comprise a cavity  27  and two linear ribs  28 . The second manipulator  26  is provided with two cams  29 , which lock behind two linear ribs  28 . In combination with the adapted end of the second manipulator  26  this combination of tool  20  and second manipulator  26  provide for a non-rotatable, locked connection. 
     The safety device  23  has a guide  30  in which the end  31  of the manipulator  24  is inserted. The guide  30  has a slot  32  (see  FIG. 6 ) in which the end  31  of the manipulator  24  is inserted. By rotating the manipulator  24  to the position shown in dashed lines of the end  31  shown in  FIG. 6 , a connection is established between the manipulator  24  and the safety device  23  and the latter can be operated. 
       FIG. 8  shows a tool  40  having a receiving end  41  and a tool body  42 . The insert  43  in the tool body  42  is similar to the insert  9  shown in  FIG. 1 . The safety device  44  is provided with a cylinder  45  which enables actuation of the safety device  44  by providing compressed air into the chamber  46 . By inserting the manipulator  47  into the bush  43  a non-rotatable connection is created between the manipulator  47  and the tool  40 . The extremity of the manipulator  47  is provided with an outlet opening  48  which connects to a channel  49  running to the cylinder  45 . So after insertion of the manipulator  47  into the bush  43  compressed air can be supplied to the chamber  46  and the safety device  44  can be actuated. 
     Instead of using a pneumatic line an optical line and also an electric line can be used to operate an electrical actuator or to read out a memory provided in the tool, or mechanical operation can be performed by for example a push rod. Also a polymer can be used as actuator. 
     Although in the embodiments a safety device with retractable safety member is shown, also other embodiments of safety devices can be used in combination with the invention, such as a safety member which extends from the top of the receiving end and is movable between a tool locking position and a tool releasing position.