Patent Application
20110064533
This application claims priority to co-pending German Patent Application No. DE 10 2009 041 337.5 entitled “Bohrmaschinen-Werkzeug”, filed Sep. 15, 2009.
The present invention generally relates to a drilling machine tool used for at least partially removing a coating or a layer of a base body of a tube.
Tubes are provided with coatings. In the case of a tube made of iron, a coating might be provided for a protection of the tube against corrugation or transport damages. In case that an axial section of the outer surface of the tube serves as a functional surface, the coating is not suitable for building the functional surface. This is due to the material properties, pores, protrusions, openings, inhomogeneities, stiffness, hardness and other properties of common coating materials. Furthermore, in some cases it is not possible to keep an outer diameter or roundness of the outer surface within given tolerances. When coating the tube by dipping the tube into a fluid, e.g. a lacquer or enamel, the outer diameters of the outer surface of the coating as well as the roundness of the outer surface vary in an extent making the coating unsuitable for building a functional surface. Furthermore, the coating might comprise hardened drops, scratches or cracks. In case that the functional surface of the tube or the coating is used as a contact surface for a sealing element, the aforementioned defects of the functional surface might lead to a leakage between the sealing element and the functional surface and/or increased wear.
EP 1 797 982 A1 relates to a tool with a blade. The position of the blade is adjusted to the dimensions of the work piece prior to the use of the tool. In use the tool is stationary held by the user and pressed against a rotating tube.
U.S. Pat. No. 5,733,074 A relates to a manual tool for removing material from brittle or non-ductile stock. The front surface of the tool is equipped with cutting members. The user presses the drilling machine with the attached drilling machine tool in axial direction against a wall such that the cutting members cut in axial direction into the wall. Additional ultrasonic torsion vibrations increase the efficiency of the drilling machine tool. The drilling machine tool is used in the construction industry for the installation of various electrical and mechanical equipment to work on the construction material, such as concrete, with or without reinforcing steel, wood, masonry and also metal for removing material to prepare openings or channels for various equipment and fittings or recesses or depressions for plug-in sockets.
The present invention relates to a tool for providing an improved functional surface of a tube. In particular, the invention provides a simple procedure for at least partially removing a coating or layer of a base body of a tube. One object of the invention is to provide a design of the tool leading to low costs.
According to one embodiment of the invention, the invention suggests using a drilling machine for at least partially removing the coating or layer instead of using a tool moved by zo hand as disclosed in EP 1 797 982. In the sense of the present invention, a “drilling machine tool” is any tool that is driven by a drilling machine of any type for a rotational movement. To name only some examples, the drilling machine tool might be coupled with a hand drill, a cordless hand drill or cordless screwdriver. Accordingly, the inventive drilling machine tool provides the option of using a drilling machine of any type in a multifunctional way, i.e. for its usual purposes as well as for driving the inventive drilling machine tool.
The inventive drilling machine tool is equipped with a blade. For a tool not covered by the present invention, a coating or layer is removed by a grinding process, wherein a grinding body is pressed with a contact surface against the outer surface of the coating or layer. For these grinding processes, after a short operating time ground particles of the coating or layer close the valleys between the tips of the surface of the grinding body such that the grinding process becomes more and more ineffective. Furthermore, the tips and valleys of the surface of the grinding body might smooth out during the grinding process. Instead, according to the invention, a cutting process is used. The efficiency of the blade is in general not deteriorated by the removed particles. The design of the cutting edge of the blade, the choice of the material of the blade and any possible hardening processes for the cutting edge of the blade as well as the geometry of the cutting blade might be chosen for guaranteeing a long lifetime of the blade making the blade suitable for a large number of operations. However, the invention also covers embodiments where both a blade as well as other elements as grinding elements are used.
It is possible to displace the cutting edge in radial inner direction towards the rotational axis of the drilling machine tool (and towards the longitudinal axis of the tube). An activation element biases the blade versus the rotational axis, so versus the outer surface of the tube. The activation element along the degree of freedom of the blade in radial inner direction causes a cutting force between the cutting edge of the blade and the outer surface of the tube or the layer of the coating. When driving the drilling machine tool by the drilling machine for a rotational movement, the cutting edge is moved relatively to the tube in circumferential direction of the tube.
The cutting edge is designed, configured and orientated such that the cutting edge preferably does not contact the outer surface of the tube at one single discrete contact point but with an extended extension at the outer surface of the tube. In some cases, the axial extension of the contact of the cutting edge with the tube corresponds to the desired axial extension of the functional surface to be produced.
To say it in simplified words, the working method of the inventive drilling machine tool might be described as a peeling tool. The “peeling” effect of the drilling machine tool does not necessarily lead to one integral chip but might lead to a plurality of chips or also smaller cut particles.
For the orientation of the cutting blade and the cutting edge in a cross-section transverse to the rotational axis the following applies: In a first extreme orientation the blade might have an orientation in radial direction. In the opposite extreme position, the cutting blade in the mentioned cross-section might have an orientation in circumferential direction of the tube. For this extreme orientation, the cutting movement of the blade might—in a simplified explanation—be seen similar to the peeling of an apple or potato. Any angular orientation of the blade and the cutting edge between the aforementioned extreme orientations is also covered by the present invention.
For one embodiment of the invention, due to the cutting force caused by the actuating element at the beginning of the working process when the drilling machine tool is still at rest the blade enters into the coating or layer of the tube. With the rotation of the drilling machine tool by the drilling machine, the cutting depth of the blade does not change significantly. However, in a preferred embodiment during the rotational movement the blade cuts deeper and deeper into the coating or layer of the tube such that the route of the cutting edge builds a spiral when seen in a cross-section of the tube.
In the present application, orientations as “parallel”, “in radial inner direction” and “in circumferential direction” both cover exact orientations or deviations from these orientations of up to 1°, 2°, 5° or also 10°.
According to another embodiment of the invention, the cutting edge has an orientation parallel to the rotational axis of the drilling machine tool. Such orientation has the effect that the cutting edge builds a straight contact line with the outer surface of the tube. The longitudinal contour of the cutting edge corresponds to the manufactured contour of the functional surface: in case of a straight cutting edge the functional surface is cylindrical. In case of using any differing contour of the cutting edge in longitudinal direction, e.g. convex or concave cutting edge contours, any differing shapes of the functional surface might be manufactured.
Any type of activation element for biasing the blade in radial inner direction might be used for the present invention. To name only some examples, the drilling machine tool might comprise an eccentric weight located distant from the rotational axis. The rotation of the drilling machine tool causes an inertial force acting upon the inertial mass of the eccentric weight. This force might be transferred to the blade via a suitable transmission or transfer mechanism leading to an activation force and cutting force. This cutting force might be dependent on the rotational velocity of the drilling machine tool. Accordingly, by controlling the driving velocity of the drilling machine it is possible to adapt the cutting force and the manufacturing characteristics of the drilling machine tool. Another example for an activation element that might be used for the present invention is an activation element manually adjusted to a desired cutting force by use of an adjusting element that might change the position of one end of a biasing spring. For a very simple embodiment of the invention, the cutting force is a produced by a spring element, e.g. a leave spring, an elastomer spring or a spiral or compression spring. Besides the low costs of such spring elements, this embodiment leads to a reproducible cutting force that is not or only to a small extent dependent on the rotational velocity of the drilling machine tool. Furthermore, the use of a spring element leads to the advantage that the use of the drilling machine tool is not necessarily restricted to tubes with an outer diameter within a small tolerance band. Instead, the spring element allows an automatic adaptation to differing outer diameters of the tube. Here, the spring element allows an adjusting movement of the blade for differing tube diameters but guarantees a cutting force within a defined cutting force range which is dependent on the chosen spring characteristic. For the spring characteristic and the chosen cutting force there are a lot of different options. In case of the coating to be removed being enamel or lacquer, a spring element might be chosen having a stiffness and design leading to a cutting force in the range from 10 to 80 N, in particular 20 to 50 N or 25 to 40 N for each centimeter length of the cutting edge.
The inventive drilling machine tool comprises a guiding element for aligning the base body of the drilling machine tool with the tube and for defining a rotational axis for a rotational movement of the base body around the tube. The guiding element guarantees a functional surface which is rotationally symmetrical to the longitudinal axis of the tube.
For the guiding element, a plurality of embodiments exist. To name only one example, the guiding element might be built with at least one supporting body supporting the tube at its inner and/or outer surface. It is possible that the supporting body provides a supporting force with at least one supporting force component having an orientation opposite to the cutting force applied by the blade on the tube. In case of a blade in a drilling machine tool interacting with the outer surface of the tube at a 12-o'clock-position, one supporting body might be positioned in the 6-o'clock-position or two supporting bodies might be positioned in a 4-o'clock-position and an 8-o'clock-position leading to symmetrical forces. The person with skill in the art will know that also a differing number of blades and/or supporting bodies might be used with differing positions and orientations.
For one embodiment of the invention, the supporting body comprises a rough surface contacting the tube. The rough surface might lead to a roughening effect of the outer surface of the tube for easing the subsequent cutting process of the blade. However, it is also possible that the supporting body comprises a smooth outer surface.
For one embodiment, the supporting body builds a sliding contact with the outer surface of the tube which might also strengthen the aforementioned roughening effect or also lead to a kind of additional grinding effect.
For another embodiment of the invention, it is suggested to use at least one rotatable cylindrical supporting body. With a rotational movement of the drilling machine tool, the supporting body builds a rolling contact with the outer surface of the tube leading to a good guidance between the drilling machine tool and the tube.
For another embodiment of the invention, the drilling machine tool comprises at least one chamber for receiving material removed by the cutting edge. The chamber housing the removed particles guarantees that the function of the drilling machine tool is not deteriorated by cut particles during the working process of one single tube or subsequent working processes of a plurality of tubes.
Furthermore, it is possible that the particles removed from the tube are removed from the chamber of the drilling machine tool after a given number of working processes or only in cases that the chamber is sufficiently filled. It is possible to remove the material from the chamber by knocking the tool against another body, by blowing the receiving chamber with pressurized air and the like. Furthermore, it is possible that at least one removing channel extends from the receiving chamber for removing material or particles during or subsequently to the working process from the drilling machine tool. Furthermore, it is possible that the removal and/or an airstream for the removal of the material or particles through those channels might be automatically caused by the rotation of the drilling machine tool. For these embodiments, the outer surface of the drilling machine tool or the base body of the same might be equipped with suitable openings and/or wings for guiding and causing the desired airstream.
In case that it is desired to produce a functional surface with a given distance from a front surface of the tube, the invention suggests equipping the drilling machine tool with an end stop. The end stop defines the end position when introducing the tube into the drilling machine tool.
For another embodiment of the invention, the drilling machine tool is multifunctional such that it is not only designated for removing a coating or layer of the tube. For one embodiment, the invention suggests providing at least one burr removing element for removing burrs from the front surface of the tube, in particular from an inner and/or outer edge of the tube. The burr removing element is rotated by the drilling machine relative to the tube might. For this embodiment, it is e.g. possible to use tubes that have been cut by a chop saw, a band saw, a tube cutter or other imprecise tools, wherein the caused burrs or bulges are removed by the burr removing element.
It is also possible that due to an imprecise cutting process of the tube, the front surface of the tube does not have an orientation transverse to the longitudinal axis of the tube. In such case the invention suggests a drilling machine tool, wherein the burr removing element is resiliently supported at the front surface of the tube for allowing an adjusting movement of the burr removing element during the rotation of the drilling machine tool relatively to the tube.
In case of using one and the same drilling machine tool for working tubes of two zo differing diameters, it is possible to provide the drilling machine tool with an adjusting element. For one embodiment, the adjusting element changes the distance of the blade (and the spring element) from the rotational axis of the drilling machine tool. It is also possible that the adaptation to differing tube diameters is done by an exchange of the blade and by using blades having differing dimensions. Furthermore, it is possible to use one and the same blade and spring element for differing tube diameters but to use differing guiding elements or supporting bodies for working differing tube diameters.
Prior to starting the drive movement of the drilling machine the tube is introduced into the drilling machine tool. During this introducing movement, it might be of advantage that the bade is not biased in radial inner direction which leads to a longitudinal cut of the blade in axial direction into the coating or layer. By suitable measures, e.g. a resting or locking device, the blade might be held in a position distant from the tube throughout the introducing phase. The locking or resting unit is unlocked at the end of the introducing phase which might be done manually or automatically when reaching the end position or end stop or a trigger for unlocking. In case of the blade already being biased by the cutting force when introducing the tube into the drilling machine tool, the cutting blade might be equipped with a lead-in chamfer. At the start of the introducing process, the blade is pushed by the activation element in the innermost radial position. Accordingly, at the start of the introducing process of the tube into the drilling machine tool, the front surface of the tube comes into contact with the lead-in chamfer. By pressing the tube into the drilling machine tool, the front surface slides along the lead-in chamfer and pushes the blade in radial outer direction. This movement of the blade in radial outer direction might increase the bias of the spring element supporting the blade against the base body of the drilling machine tool.
For the coupling of the drilling machine tool with a drive of the drilling machine, there are a lot of different possibilities. For a very simple embodiment, a coupling element with a polygonal cross-section, in particular a hexagonal cross-section is used that might be coupled with known drill chucks of an accumulator-powered hand drill or any other drive unit.
For another embodiment of the invention, the blade is exchangeable. In case of wear of the blade leading to a decrease of the efficiency of the drilling machine tool or a deterioration of the produced functional service, the blade is exchanged. It is also possible that the blade is exchanged for adapting the drilling machine tool to different tube diameters, for manufacturing functional surfaces with differing contours and the like.
Any type of cutting edge might be used, wherein any cross-sectional contour of the cutting edge, any material and any hardening process might be used. For one embodiment of the invention, a broken cutting edge is used leading to an increased lifetime of the cutting blade.
For one embodiment of the invention, only one blade interacts with the outer surface of the tube. However, it is also possible that a plurality of cutting blades is used, wherein the cutting blades are positioned at differing axial regions and/or circumferential positions. The cutting blades might be equipped with the same or differing cutting edges and might be pressed against the tube with the same or differing cutting forces. It is also possible that only one of the plurality of blades is selectively activated for the working process of tubes having a diameter in a special range of diameters.
For increasing the operational safety of the drilling machine tool, a sliding clutch or security clutch might be integrated into the drilling machine tool. In case of the blade interlocking with the tube during the working process, the sliding or safety clutch might separate the drive train from the drilling machine to the tool for avoiding unsafe operational states or impulse-like forces acting on the hand of the user.
The housing of the drilling machine tool might be built from any known material, e.g. metal. One embodiment of the invention suggests using a housing of the drilling machine zo tool being partially or completely built from a plastic material which reduces the costs and the rotating weight. Furthermore, any known manufacturing process for building a housing from a plastic material, in particular injection molding, might be used. Furthermore, the use of plastic leads to a plurality of options for the design and shape of the housing.
The inventive drilling machine tool in particular will be used for at least partially removing a coating or layer of a tube for providing a functional surface for a sealing element.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and the detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.
The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring now in greater detail to the drawings,
The drilling machine tool 10 comprises a housing 11. The housing 11 comprises a protrusion building a drive element. For the shown embodiment, the drive element is a protrusion with a hexagonal cross-section. This protrusion is coupled with the chuck of a drilling machine. The protrusion 12 defines a longitudinal and rotational axis 13. The housing 11 has in a first approximation a pot-like shape with a U-shaped longitudinal section, wherein the parallel side legs of the U are symmetrical to the longitudinal axis 13-13 and the base leg of the U has an orientation transverse to the longitudinal axis 13-13. The base leg of the U builds a disc-like base plate 14, whereas the side legs build a hollow cylindrical wall 15 of the housing 11.
As can be seen from
The housing 11 builds a chamber 24 having one open end for receiving tube 1. Chamber 24 is defined in radial outer direction by wall 15 and in axial direction by base plate 14. The wall 15 comprises openings 25, 26 being closed in circumferential direction and communicating with chamber 24. Guiding elements 27, 28 are received in recesses 25, 26. For the shown embodiment, the guiding elements 27, 28 build supporting bodies 29, 30, here rotatable rolls 31, 32. The rolls 31, 32 or cylindrical supporting bodies are borne by bolts 33, 34 for a rotating movement. The bolts 33, 34 have an orientation parallel to the longitudinal axis 13-13 and extend through the openings 25, 26. The bolts 33, 34 are housed with their end regions in bores 35, 36; 37, 38. The bolts 33, 34 extend through the longitudinal bores 39, 40 of the rolls or cylinders 31, 32. As can be seen from
For a use of the drilling machine tool 10, the drilling machine tool 10 is coupled with its hexagonal cross-section 12 with a chuck of a drilling machine. Subsequently, the tube to be worked is introduced into the receiving chamber 24 of the drilling machine tool 10. For the shown embodiment, the cutting blade 12 is positioned in a 12-o'clock-position in a cross-section of the drilling machine tool, whereas the guiding elements 27, 28 are positioned in a 4-o'clock-position and an 8-o'clock-position. During the introducing process of the tube 1 into the receiving chamber 24, the outer surface 51 of the tube slides in axial direction along the outer surface of the rolls or cylinders 31, 32 without any rolling movement of the rolls 31, 32 along the outer surface 51 of the tube. However, the contact of the outer surface 51 of the tube 1 with the rolls 31, 32 determines the distance of the outer surface 51 of the tube 1 from wall 15. For a contact of the surface 51 of the tube 1 with the two rolls 31, 32, the longitudinal axis 13-13 of the drilling machine tool 10 and the longitudinal axis 9-9 of the tube 1 are aligned with each other. At the beginning of the introducing process of tube 1 into the receiving chamber 24, the cutting plate 17 due to the activation of the elastic sheet metal is in the radial innermost position. The front surface 7 of the tube 1 comes into contact with the lead-in chamfer 23 of the cutting blade 17. Further movement of tube 1 displaces the front surface 7 of the cutting blade 17 in radial outer direction. At the end of this radial movement of the cutting blade 17, the cutting edge 47 of cutting blade 17 slides along the outer surface 51 of tube 1. An end position of tube 1 is reached when the front surface 7 of the tube 1 abuts at base plate 14 or an end stop mounted with the base plate 14. For the shown embodiment, the end stop is built by the burr removing elements 42-44. The cutting edges 45 interact with the outer edge 48 at the front surface 7 of tube 1, whereas the cutting edges 46 interact with the inner edge 49 of the front surface of tube 1. Further pressing of tube 1 inside the drilling machine tool 10 increases the contact force between the outer edge 48 and inner edge 49 with the cutting edges 45, 46. Now the drilling machine tool 10 is driven by the drive or drilling machine. During this driven movement, tube 1 is manually fixed or fixed by an additional holding device. The driven movement of the drilling machine tool 10 results in the following manufacturing processes:
Due to the support of the cutting blade 17 by the elastic sheet metal 22, it is possible to adapt the blade position to varying tube diameters. For one example, the cutting blade 17 and the elastic sheet metal 22 are designed such that differing diameters of the coating 3 up to 1.5 mm in difference might be adapted.
In the figures, an embodiment with one single blade 17 and two guiding elements 27, 28 is shown. However, the invention might be embodied with any differing number of cutting blades 17 and/or guiding elements 27, 28. For centering and aligning the longitudinal axes 9-9, 13-13, any differing centering and/or guiding devices might also be used. To name only one example, the drilling machine tool 10 might be equipped with a mandrel entering into tube 1. It is also possible that guiding elements, supporting bodies or rolls are supported at the inner surface of the tube 1.
In wall 15 close to the cutting blade 17 cavities, bores, recesses having an orientation in radial outer direction might be provided that build receiving chambers for particles separated by the cutting blade 17 from the tube.
Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 041 337.5 | Sep 2009 | DE | national |
