Abstract:
The invention relates to a stop for arrangement on a drilling, milling or countersinking tool for machining a work piece, wherein the work piece has a surface, and wherein the drilling, milling or countersinking tool has a cutting section. The stop comprises a contact surface, wherein the contact surface is arranged such that once a predetermined machining depth in the work piece is reached, the contact surface is seated against the surface, at least in some sections. A connecting element is provided, wherein the connecting element is arranged between the contact surface and the cutting section. The connecting element is suited to prevent a relative movement between the contact surface and the surface.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to a stop for being arranged on a drilling, milling or countersinking tool for machining a workpiece, a countersinking tool, a countersinking device for countersinking and/or deburring and a method for countersinking a workpiece. 
     BACKGROUND OF THE INVENTION 
     Stops for limiting the penetration depth of a tool into a workpiece during the machining of the workpiece with cutting tools are known from the prior art. 
     SUMMARY OF THE INVENTION 
     During the machining of workpieces, an excessively deep machining depth can be prevented with the aid of stops. In this case, the stops are arranged on the machining tool. The stops typically move together with the tool such that the surface of the workpiece may be scratched when the stop contacts the workpiece. Scratching may occur, in particular, during the machining of workpieces that consist of soft materials such as, e.g., aluminum. 
     The objective of the present invention therefore can be seen in making available a stop that largely prevents the stop from scratching and/or scraping on the surface. 
     This objective is attained with the independent claims. Other advantageous embodiments of the invention result from the dependent claims. 
     According to a first embodiment of the invention, a stop for being arranged on a drilling, milling or countersinking tool for machining a workpiece is proposed, wherein the workpiece has a surface, wherein the drilling, milling or countersinking tool features a cutting section, and wherein the stop comprises: a contact surface, wherein the contact surface is arranged such that the contact surface at least sectionally comes in contact with the surface once a predetermined machining depth in the workpiece is reached, and a connecting element, wherein the connecting element is arranged between the contact surface and the cutting section, and wherein the connecting element is suitable for preventing a relative movement between the contact surface and the surface. 
     According to the invention, the transmission of a torque from the driven cutting section of the tool to the stop is prevented such that a possibly occurring relative movement between the stop and the workpiece can be quickly stopped when the stop contacts the surface of the workpiece due to the friction between the stop and the workpiece. This makes it possible to largely prevent scraping or scratching on the surface of the workpiece such that the workpiece surface is treated with care. 
     According to a second embodiment of the invention, a countersinking tool is proposed, wherein the countersinking tool comprises: a cutting section for countersinking and/or deburring an opening of a bore and a stop according to one of Claims  1  to  3 . 
     The stop on the countersinking tool is realized adjustably such that bevels of different width or diameter can be produced with the countersinking tool. 
     A countersinking tool serves for deburring and/or for cutting a bevel on the opening of a bore. In this case, bevels with approximately identical diameters preferably should be produced. A stop can be used for this purpose. According to the invention, the countersinking tool is provided with a stop, wherein the transmission of the torque acting upon the working cutting section of the countersinking tool to the stop is prevented. The arrangement of the stop on the countersinking tool can be realized, e.g., by means of a roller bearing. 
     According to a third embodiment of the invention, a countersinking device for countersinking and/or deburring an opening of a through-bore is proposed, wherein the countersinking device comprises: a countersinking tool according to one of Claims  5  to  8  for countersinking and/or deburring the opening, wherein the countersinking tool features a first coupling section and a coupling element, wherein the coupling element features a second coupling section, and wherein the first coupling section can be separably connected to the second coupling section. 
     According to a fourth embodiment of the invention, a method for countersinking a workpiece is proposed, wherein the method comprises the steps of: countersinking by means of a countersinking device according to one of Claims  9  to  10 , wherein the countersinking tool is separably connected to the coupling element, wherein a withdrawal force is required for the separation, and wherein the countersinking tool is pressed against the workpiece with a force that is lower than the withdrawal force during the countersinking process, and retooling, wherein the countersinking tool is pressed against the workpiece with a force that is higher than the withdrawal force. 
     Exemplary embodiments are described in the dependent claims. 
     According to an exemplary embodiment of the invention, a stop is proposed, wherein the connecting element is realized in such a way that the stop is arranged rotatably referred to the drilling, milling or countersinking tool and/or wherein the connecting element is realized in the form of a roller bearing. 
     Due to the freely rotatable arrangement of the stop, e.g., on the countersinking tool, it is possible to prevent the torque that causes the cutting edges of the tool to rotate from being transmitted to the stop. 
     In one embodiment, the connecting element may consist, e.g., of a roller bearing, wherein the roller bearing may be realized in the form of a ball bearing, a cylindrical roller bearing, a needle bearing, a tapered roller bearing, a spherical roller bearing or a toroidal roller bearing. 
     According to an exemplary embodiment of the invention, a stop is proposed, wherein the stop is realized in the form of a sleeve, in which case the contact surface is realized in the form of a circular ring, or wherein the stop is realized in a rod-shaped fashion, in which case the contact surface is realized in the form of a circular disk. 
     A stop in the form of a sleeve makes it possible to ensure that the machining depth in the workpiece is never deeper than intended, namely also at oblique tool angles. 
     Alternatively, the stop may essentially be realized in the form of a rod or several rods such that a simple manufacture of the stop can be achieved. 
     According to another exemplary embodiment of the invention, a countersinking tool is proposed, wherein the countersinking tool comprises: a coupling section for being separably connected to a coupling element in order to transmit a torque to the countersinking tool. 
     According to an exemplary embodiment of the invention, a countersinking tool is proposed, wherein the coupling section is arranged on the opposite region of the countersinking tool referred to the cutting section. 
     According to another inventive embodiment, a countersinking tool is proposed, wherein the coupling section is sectionally realized in the form of a hexagon or a hexagon socket. 
     A coupling section that is realized, e.g., in the form of a hexagon or a hexagon socket can serve for transmitting a torque. 
     According to another exemplary embodiment of the present invention, a countersinking tool is proposed, wherein the coupling section features a constriction or a groove. 
     A constriction or groove on the coupling section may serve, e.g., for securing the interconnected parts of a countersinking device that may comprise a countersinking tool and a coupling element. 
     According to an exemplary embodiment of the invention, a countersinking device is proposed, wherein the first coupling section is at least sectionally realized in the form of a hexagon, and wherein the second coupling section is at least sectionally realized in the form of a hexagon socket. 
     A concept of the invention can be seen in proposing a machining tool with a stop that is realized in such a way that the torque exerted upon the cutting section of the tool cannot be transmitted to the stop. This mechanical decoupling may be realized, e.g., with a roller bearing. 
     The individual characteristics naturally may also be combined with one another and such combinations occasionally may result in advantageous effects that transcend the sum of the individual effects. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other details and advantages of the invention are elucidated below with reference to the exemplary embodiments illustrated in the drawings. In these drawings, 
         FIG. 1  shows a countersinking tool, 
         FIG. 2  shows another countersinking tool, partially in the form of a longitudinal section and partially in the form of a side view, 
         FIG. 3  shows another countersinking tool in the form of a longitudinal section, 
         FIG. 4  shows a countersinking tool, 
         FIG. 5  shows another countersinking tool, 
         FIG. 6  shows a ball, 
         FIG. 7  shows a coupling element, 
         FIG. 8  shows a countersinking device, 
         FIG. 9  shows a coupling element, 
         FIG. 10  shows another countersinking tool, and 
         FIG. 11  shows another countersinking tool. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a countersinking tool  105  for countersinking and/or deburring that features a cutting section  103  and a stop  106  that may be realized in the form of a sleeve. Alternatively, the stop may also be realized in the form of a rod or several rods. The stop  106  forms part of the countersinking tool  105  and therefore possibly moves together with the driven cutting section  103 . According to the invention, the stop  106  comes to a standstill once the intended machining depth is reached and the stop  106  comes in contact with the surface of the workpiece  102 , namely because at least one roller bearing  101 ,  107  is arranged between the driven cutting section  103  and the stop  106  and prevents a torque from being transmitted from the driven cutting section  103  to the stop  106 . In this way, the stop  106  is prevented from continuing its rotation and from scratching the surface of the workpiece  102  when it comes in contact with the surface of the workpiece  102 . The workpiece  102  may respectively consist, e.g., of aluminum, CFRP or titanium or contain aluminum, CFRP or titanium. The countersinking tool  105  comprises a coupling section  104  that may be realized, e.g., in the form of a pin. This coupling section  104  makes it possible to drive the countersinking tool  105 . The coupling section  104  may be realized, e.g., in the form of a hexagon such that a torque can be transmitted. The coupling section  104  may alternatively also be realized in the form of a recess such as, e.g., a hexagon socket. 
       FIG. 2  shows a countersinking tool  205 , a first section  201  of which is illustrated in the form of a longitudinal section and a second section  202  of which is illustrated in the form of a side view. The countersinking tool  205  features a stop  203 ,  206  that is decoupled from the driven cutting section  204  by means of at least one roller bearing  207 ,  208 . Once the contact surface  209  of the stop  203 ,  206  comes in contact with the workpiece to be countersunk and/or deburred, the stop  203 ,  206  comes to a standstill such that scraping or scratching, e.g., on a soft aluminum surface of the workpiece can be prevented. The stop  203 ,  206  may also consist of a rod  203 , two rods  203 ,  206  or more than two rods rather than a round circular sleeve, wherein the stop  203 ,  206  is always decoupled from the driven cutting section  204  of the countersinking tool  205  by means of at least one roller bearing  207 ,  208  regardless of its realization in the form of a sleeve or one or more rods or in the form of another embodiment. This ensures that the stop  203 ,  206  comes to a standstill when it comes in contact with the surface of the workpiece such that scraping or scratching can be largely prevented on the surface of the workpiece. 
       FIG. 3  shows a countersinking tool  306  with a stop  301  and a cutting section  302  in the form of a longitudinal section, wherein the stop  301  is connected to the cutting section  302  by means of at least one roller bearing  307 . Consequently, the stop  301  comes to a standstill once the contact surface  308  of the countersinking tool  306  comes in contact with the workpiece surface. The countersinking tool  306  features a recess  304  that may be realized, e.g., in the form of a hexagon socket. A complementary pin that may feature, e.g., a constriction can be inserted into this recess. For example, balls  303 ,  305  may be pressed into this constriction, e.g., by means of a spring force in order to couple the countersinking tool  306  to a driving machine. In an alternative embodiment, the countersinking tool  306  may be realized with only one ball  303  or three, four or any number of balls. 
       FIG. 4  shows a countersinking device with a countersinking tool  409  and a coupling element  416 , wherein the countersinking tool  409  features a cutting section  403  and a stop  402 ,  410 . When the stop  402 ,  410  comes in contact with the surface  413  of the workpiece  412 , the stop  402 ,  410  prevents the countersinking tool  409  from cutting further into the workpiece  412 . Due to the friction between the stop  402 ,  410  and the workpiece  412  and due to the roller bearing  401 ,  411  between the driven cutting section  403  and the stop  402 ,  410 , the stop  402 ,  410  comes to a standstill such that damages to the surface  413  of the workpiece  412  are prevented. The countersinking tool  409  can be separably connected to a coupling element  416 , wherein the countersinking tool  409  may feature a coupling section that may be realized in the form of a pin  406 . This pin  406  of the countersinking tool  409  can be inserted into a recess  405  of the coupling element  416 . In this case, a ball  404  of the coupling element  416  can be pressed into the constriction of the pin  406  in order to secure the coupling. The coupling element  416  features a shaft  407  that can be clamped into a driving machine such as, e.g., a hand drill. The shaft  407  features a bevel  408  in order to simplify the insertion of the shaft into the drill chuck. 
       FIG. 5  shows a countersinking tool  508  with a cutting section  504  and a stop  502 ,  509 , wherein the stop  502 ,  509  is connected to the cutting section  504  of the countersinking tool  508  via at least one roller bearing  501 ,  507 . The countersinking tool  508  can cut a bevel on the first surface  510  of the workpiece  503  by means of the cutting section  504 . The countersinking tool  508  features a pin  506  that may be realized in the form of a hexagon. The pin  506  serves for transmitting a torque to the countersinking tool  508 . 
       FIG. 6  shows a ball  601  that can be pressed into a constriction of the pin in order to secure the pin in a receptacle. 
       FIG. 7  shows a coupling element that features a receptacle  707 , wherein the receptacle  707  may be realized in the form of a hexagon socket in order to transmit a torque. A ball  701  that can be introduced into the coupling element through a channel  702  may be used for securing an inserted pin. The coupling element features another channel  703 , into which a bolt can be introduced that acts upon the ball such that the ball  701  is prevented from disengaging from the coupling element through the channel  702 . A spring may be arranged within the channel  703  behind the bolt in order to press the bolt toward the lower left. On its outer end, the channel  703  features an internal thread  708  such that a stud can be screwed into the channel  703 . The stud can be screwed into the channel  703  to different depths such that the pressure exerted upon the bolt by the spring can be varied. All in all, this makes it possible to vary the pressure exerted upon an inserted pin by the ball  701 . In its lower region, the channel  702  advantageously has a diameter that is smaller than the ball such that the ball  701  is prevented from falling out when the pin is removed. 
       FIG. 8  shows a countersinking device with a countersinking tool  814  that features a stop  802 ,  815 , wherein the stop is connected to a cutting section  805  by means of a roller bearing  807 ,  811 . The countersinking tool  814  is separably connected to a coupling element  816 . The connection is produced with the aid of a pin  812  that can be inserted into a recess  813 , wherein the pin  812  may be realized in the form of a hexagon and the recess  813  may be realized in the form of a hexagon socket in order to transmit a torque from the coupling element  816  to the countersinking tool  814 . The coupling element  816  features a channel  807  for inserting a ball  806  into the coupling element  816 , as well as a channel  808  that can accommodate a bolt/spring/stud arrangement for exerting pressure upon the ball  806 . The coupling element  816  features a shaft  810  in order to clamp the coupling element  816  into the drill chuck, e.g., of a hand drill. 
       FIG. 9  shows a coupling element with a ball  901  that is designed for engaging into the constriction of an inserted pin. The ball  901  is pressed in the direction of the recess by a bolt  902 , wherein the bolt  902  may be realized in a wedge-shaped fashion. The bolt  902  is pressed against the ball  901  by a spring  903 , wherein the spring force can be varied with the aid of a stud  904  that can be screwed into the channel to different depths. All in all, this makes it possible to vary the pressure exerted upon the ball  901  by the bolt  902 . When the stud  904  is screwed deeper into the channel  906 , the pressure exerted upon the ball  901  by the bolt  902  increases. The bolt  902  is pressed against the ball  901  with a decreasing force as the stud  904  is unscrewed. A variation of the force exerted upon the ball  901  makes it possible to vary the force required for respectively inserting and withdrawing a pin into/from the recess  905 , wherein this force is also referred to as withdrawal force. 
       FIG. 8  shows a countersinking tool  814  that is separably connected to a coupling element  816 , wherein the countersinking tool  814  cuts a bevel into the workpiece  804  when the countersinking device is displaced in the direction of the arrow  818 . During this process, it needs to be ensured that the countersinking tool  814  is pressed against the surface  803  in order to cut the bevel with a force that is lower than the withdrawal force so as to prevent the countersinking tool  814  from being withdrawn, i.e., separated, from the coupling element  816  during the countersinking process. After the countersinking process is completed, the countersinking tool  814  can be pressed against the surface  803  of the workpiece  804  in the direction of the arrow  818  with an increasing force, namely until this force exceeds the withdrawal force in order to thusly separate the countersinking tool  814  from the coupling element  816  and initiate a retooling process. Consequently, the force that presses the ball  806  against the pin  812  needs to be adjusted such that the countersinking process can be carried out without separation of the countersinking tool  814 . On the other hand, this force should not be adjusted excessively high in order to allow the withdrawal of the countersinking tool  814  by pressing it against the workpiece  804  and thusly initiate a retooling process. 
       FIG. 10  shows a countersinking tool with a pin  1006  that it may be realized in the form of a hexagon, wherein the hexagon may feature a recess or constriction  1008  in order to be coupled to another (not-shown) tool element (quick-change adapter). In this case, the drive of the countersinking tool may be realized with the other tool element. Furthermore, a roller bearing  1001  is arranged on the countersinking tool and may be realized in the form of a double-row angular ball bearing, wherein the angular ball bearing may be tensioned and therefore realized without play. The inner race furthermore can accommodate the pins of both countersinks (e.g., bonding with Loctite). The countersinking tool may comprise a sleeve  1002 , wherein the sleeve  1002  may be connected to the remaining countersinking tool by means of the roller bearing  1001  such that the transmission of a torque, e.g., from the pin  1006  to the sleeve  1002  can be prevented. The sleeve  1002  may serve as a depth stop and does not continue to rotate when it comes in contact with a surface of a workpiece to be machined due to the roller bearing  1001  such that the surface of the workpiece can be treated with care. For example, the sleeve  1002  may be bonded to the roller bearing  1001 . The countersinking tool features a tapered section  1007  such that the insertion of the countersinking tool into the other tool element can be simplified. The countersinking tool can be used as backward countersink and/or forward countersink, wherein a first cutting section  1005  can be used for countersinking in a backward countersinking process and a second cutting section  1003  can be used for countersinking in a forward countersinking process. In an alternative embodiment, the countersinking tool may feature a rounded pin  1004  such that the insertion into a bore of a workpiece to be countersunk can be simplified and the surface of the workpiece can be treated with care during the insertion. 
       FIG. 11  shows a countersinking tool with a pin  1101  for being coupled to a (not shown) driving tool element, wherein the pin  1101  may feature a tapered section  1109  in order to simplify the insertion into the driving tool element. The countersinking tool features a first cutting section  1102  that is suitable for backward countersinking. The countersinking tool furthermore features a second cutting section  1107  that may be suitable for forward countersinking. The countersinking tool is provided with a sleeve  1104  that may be realized in the form of an aluminum housing and connected to the remaining countersinking tool by means of a roller bearing  1105 . The roller bearing  1105  may be realized in the form of an angular ball bearing. The sleeve  1104  may feature two stops  1103 ,  1106 , wherein the stop  1103  is provided for backward countersinking and the stop  1106  is provided for forward countersinking. In order to carry out the countersinking process, a cutting section  1102  can be used for backward countersinking and another cutting section  1107  can be used for backward countersinking. The sleeve  1104  can be adapted, e.g., after its installation on the countersinking tool in such a way that the cutting sections  1102 ,  1107  can cut into a bore of a workpiece to be countersunk to the desired depth. A pin  1108  may be used for inserting the forward countersink. In an alternative embodiment, the pin  1108  may be rounded in order to prevent a surface of a workpiece to be processed from being scratched or damaged during the insertion of the forward countersink. 
     It should be noted that “comprising” does not exclude other elements or steps, and that “a” or “an” does not exclude several elements and steps. 
     The reference symbols used merely serve for the better understanding of the invention and should by no means be interpreted in a restrictive sense, wherein the scope of protection of the invention is reflected by the claims.