Patent Application
20130218162
1. Prior Art
The invention relates to a tool, in particular for use as a surgical drill.
2. Background
EP 1 943 966 B1 has already disclosed a tool for use as a surgical drill, having a main tool body which, in order to be connected to a tool attachment unit of a drive device, has a fixing unit which is provided to be at least partly unusable after the main tool body has been detached from the tool attachment unit.
The objective of the invention is in particular to make available a tool which, with a high degree of strength, in particular in respect of axial forces, can be fastened to a tool attachment unit. The object is achieved in particular by the features of the independent claims, while further embodiments can be derived from the dependent claims.
The invention relates to a tool, in particular for use as a surgical drill, having a main tool body which, in order to be connected to a tool attachment unit, has a fixing unit which is provided to be at least partly unusable after the main tool body has been detached from the tool attachment unit.
It is proposed that the fixing unit has at least one form-fit element which is provided to accept axial tensile forces in order to axially secure the main tool body to the tool attachment unit. In this way, axial forces acting on the form-fit element can be transferred particularly advantageously to the tool attachment unit, as a result of which a particularly firm connection can be achieved for axially securing the tool. The phrase “provided to be at least partly unusable after the tool has been detached” is to be understood in particular as meaning that the fixing unit is designed such that it is no longer usable after the tool has been detached only several times, but preferably after the tool has been detached for the first time, specifically preferably in such a way that renewed axial fixing of the tool is no longer possible. Here, “axial tensile forces” are to be understood in particular as meaning that the form-fit element is provided to accept forces that lead to tensile loading of the form-fit element and to pass these forces on to the tool attachment unit via a form fit. “Tensile forces” are to be understood as forces that in principle would lead to an elongation of the form-fit element if the form-fit element were made of an elastic material. Moreover, in this context, “provided to axially secure” is to be understood as meaning that the form-fit element is intended to transfer axial forces acting on the tool to the tool attachment unit in the form of a tensile load. “Provided” is to be understood in particular as specially equipped and/or designed.
The fixing unit may have an assembly direction and a deflection element which points in the assembly direction and which is provided for movably attaching the form-fit element to the main tool body. In this way, a particularly advantageous transfer of the tensile forces from the main tool body to the form-fit element can take place. The deflection element is in this case preferably provided for a radial deflection of the form-fit element. An “assembly direction” is to be understood in particular as a direction that extends parallel to a rotation axis of the tool and that is provided for mounting the tool on the tool attachment unit. It is preferably to be understood as a direction which is oriented from a tip of the tool, which tip is provided with drilling teeth, in a direction of an end at which the main tool body has the fixing unit. A “deflection element” is to be understood in particular as an element which is provided for deflecting the form-fit element with respect to the main tool body.
The form-fit element and the deflection element may have different directions of extension. A particularly advantageous fixing unit can be obtained in this way. A “direction of extension” is to be understood in particular as a direction that is oriented along a jacket surface and/or surface of the form-fit element or of the deflection element. Different “directions of extension” are to be understood in particular as meaning that a surface of the form-fit element and a surface of the deflection element are arranged at an angle to each other.
In a particularly advantageous embodiment, the form-fit element and the deflection element are arranged at an acute angle to each other. In this way, it is possible to obtain a particularly advantageous form fit which is provided by the form-fit element and which permits safe axial securing of the tool on the tool attachment unit. An “acute angle” is to be understood in particular as an angle of less than 90 degrees, with the deflection element and the form-fit element preferably having surfaces that enclose the acute angle. Advantageously, the surface of the form-fit element is provided as a contact face for fastening the main tool body and particularly advantageously encloses the acute angle with a surface of the deflection element that is oriented in the direction of an interior space of the main tool body.
It is also advantageous if the form-fit element and the deflection element are formed in one piece. In this way, the form-fit element and the deflection element can have a particularly simple design. The deflection element and the form-fit element are preferably made in one piece with the main tool body.
It is further proposed that the form-fit element is bent at an angle of at least 90 degrees with respect to the deflection element. The form-fit element can be realized particularly easily in this way. The phrase “bent at an angle of at least 90 degrees” is to be understood in particular as meaning that the form-fit element is produced by a plastic deformation of a one-piece component of which one portion, which constitutes the form-fit element, is bent at an angle of at least 90 degrees with respect to a remaining portion, which constitutes the deflection element.
In a particularly advantageous embodiment, the main tool body has an end with a free cut, which constitutes at least the form-fit element. In this way, the form-fit element and the deflection element can be realized particularly easily. Herein, the form-fit element is preferably produced by bending out a portion of the free cut. A “free cut” is to be understood in particular as a portion of the main tool body, which portion, by introduction of at least one but preferably two incisions, forms a tongue or tab which is provided to constitute the form-fit element and the deflection element. An “end with a free cut” is to be understood in particular as meaning that the free cut is introduced into the main tool body from the direction of the end of the main tool body.
In a further embodiment, it is proposed that the free cut at least partially forms a recess which is provided to transfer a torque. In this way, the tool can be embodied with a particularly simple design. In particular, in this way, the recess for transferring a torque and the form-fit element for axial securing can be made in one piece and thus combined with each other, as a result of which a particularly simple design of the fixing unit is possible.
It is moreover advantageous if the fixing unit is provided to form a plug connection. A simple fixing unit can be realized in this way.
A tool with a main tool body may be provided to be connected to a tool attachment unit so as to rotate therewith and has a fixing unit, which is provided to be at least partly unusable after the main tool body has been detached from the tool attachment unit, wherein the fixing unit forms an attachment seat provided for plugging onto the tool attachment unit. It is possible in this way to achieve particularly secure fixing of the tool to the tool attachment unit. In particular, the fixing unit can thus have a particularly simple design. An “attachment seat” is to be understood in particular as an interior space which is enclosed by the main tool body and into which a plug-on element of the tool attachment unit can be introduced, and in which the plug-on element, in the assembled state, is arranged for conjoint rotation and is axially secured.
The invention also proposes a tool-fixing device for connection to a tool according to the invention, which tool-fixing device has a tool attachment unit, which is provided to drive a tool about a rotation axis in a rotational movement, and which has a plug-on element, which is provided to pass at least partially through a main tool body, and at least one form-fit engagement element, which is provided to receive a form-fit element of the tool in order to secure the tool against an axial movement. In this way, a particularly advantageous and simple tool-fixing device can be made available. A “form-fit engagement element” is to be understood as an element that forms a contact face which the form-fit element of the tool abuts.
The form-fit engagement element preferably has at least one contact face for the form-fit element, which contact face is designed as an oblique face in relation to a cross-sectional face. In this way, axial tensile forces acting on the form-fit element can be converted at least partially into radially acting forces, as a result of which undesired slipping of the form-fit element out of the form-fit engagement element can advantageously be prevented. A “cross-sectional face” is to be understood as a face extending perpendicularly with respect to the rotation axis. In this context, designed as an “oblique face” is to be understood in particular as meaning that the contact face of the form-fit engagement element encloses an angle of different than zero degrees with the cross-sectional face. Preferably, the angle is approximately 15 degrees. In the context of angles, “approximately” is to be understood here, and in the text below, as a deviation by at most ±10 degrees, with a deviation by at most ±5 degrees being advantageous, and a deviation by at most ±1 degree being particularly advantageous.
Preferably, the form-fit engagement element at least partially forms an undercut. The securing of the form-fit element in the form-fit engagement element can be obtained particularly simply in this way. An “undercut” is to be understood in particular as meaning that the form-fit engagement element has a structure that is implemented as an undercut with respect to the radial direction, which means that a portion of the contact face is designed as a recess, with respect to the radial direction, in which the form-fit element engages.
It is further proposed that the plug-on element has a recess for forming the form-fit engagement element. In this way, the form-fit engagement element can have a particularly simple design. Preferably, the plug-on element and the form-fit engagement element are designed in one piece.
In a refinement, it is proposed that the plug-on element has an oblique face, which is provided to deflect the form-fit element of the tool. In this way, when the tool is plugged onto the tool attachment unit, the form-fit element can be introduced particularly easily into the form-fit engagement element, as a result of which the tool can be secured to the tool-fixing device in a simple way.
It is also advantageous if the tool-fixing device has a drive attachment unit, which is provided for releasable attachment to a drive device. In this way, the tool-fixing device can be designed as an adapter, as a result of which existing drive devices can continue to be used. A “drive device” is to be understood as a device with at least one drive motor, which is provided to impart a rotational movement to the tool.
The invention moreover proposes a system with a tool according to the invention and with a tool-fixing device according to the invention.
Further advantages will become clear from the following description of the drawing. The figures depict an embodiment of the invention. The figures, the description and the claims contain numerous features in combination. A person skilled in the art will also consider the features individually, where appropriate, and combine them to form expedient further combinations.
A tool 10 according to the invention is shown in
The main tool body 12 has a tip 28, which is provided for drilling the hole into the bone, and an end 19, which is provided for connection to a drive device (not shown) for rotation therewith. The tool 10 thus forms a surgical instrument.
At its tip 28, the main tool body 12 has drilling teeth 29 forming a grinding or cutting device, by means of which the hole can be drilled in bone. To form the drilling teeth, diamond elements are mounted on the tip 28 of the main tool body 12. The diamond elements are made of artificial diamonds. In order to remove drill cores, the main tool body 12 is designed in a tubular shape at least at the tip 28.
At its end 19, the main tool body 12 has a fixing unit 14. The fixing unit 14 is provided for connecting the main tool body 12 to a tool attachment unit 13 of the drive device, so as to rotate therewith while being secured against axial movement. The fixing unit 14 forms part of a plug connection. By means of the fixing unit 14, the main tool body 12 is connectable to the tool attachment unit 13 by a linear movement along the rotation axis 22. The main tool body 12 is also designed in a tubular shape at the end 19. It can thus be plugged onto the tool attachment unit 13. A direction of the linear movement herein defines an assembly direction 16 for the fixing unit 14. The assembly direction 16 is oriented from the tip 28 to the end 19. The movement by which the main tool body 12 is connectable to the tool attachment unit 13 is oriented along this assembly direction 16.
The tool 10 is provided as a disposable tool. To make it difficult or impossible for the tool 10 to be used more than once, the fixing unit 14 is designed such that it is at least partly unusable after the main tool body 12 has been detached from the tool attachment unit 13. Upon detachment of the main tool body 12 from the tool attachment unit 13, the fixing unit 14 is deformed or altered in such a way that it is no longer possible for the main tool body 12 to be fixed anew on the tool attachment unit 13, so as to rotate therewith, while being axially secured.
To axially secure the main tool body 12, the fixing unit 14 comprises a form-fit element 15, which is provided to accept axial tensile forces. The form-fit element 15 is designed as a hook which, in a state of assembly, engages in a corresponding form-fit engagement element 24 of the tool attachment unit 13. The form-fit element 15 herein secures the main tool body 12 against the axial movement. The tensile forces, which are taken up by the form-fit element 15 in order to axially secure the main tool body 12 to the tool attachment unit 13, are forces that act counter to the assembly direction 16.
In order to attach the form-fit element 15 to the main tool body 12, the fixing unit 14 has a deflection element 17 via which the form-fit element 15 is connected to the main tool body 12. The deflection element 17 comprises a first end, which is connected to the main tool body 12, and a second end, which is connected to the form-fit element 15. Starting from the end connected to the main tool body 12, the deflection element 17 extends in the direction of the form-fit element 15.
The deflection element 17 is provided for movably attaching the form-fit element 15 to the main tool body 12. The form-fit element 15 and the deflection element 17 form part of a latching unit, which is provided for axially securing the main tool body 12 to the tool attachment unit 13. Starting from the end of the deflection element 17 connected to the main tool body 12, the deflection element 17 points in the assembly direction 16, i.e. in the direction of the end 19. The deflection element 17 is designed in the form of a tab or tongue that is oriented in the direction of the end 19 of the main tool body 12.
The form-fit element 15 and the deflection element 17 have different directions of extension. The deflection element 17 extends substantially parallel to the rotation axis 22. In a state as delivered, an angle between the direction of extension of the deflection element 17 and the rotation axis 22 is approximately zero degrees. The form-fit element 15 extends substantially perpendicularly with respect to the rotation axis 22. An angle 18 included by the direction of extension of the form-fit element 15 in the state as delivered and the main rotation axis 22 is approximately 75 degrees. The angle 18 at which the form-fit element 15 and the deflection element 17 are arranged in relation to each other is therefore configured as an acute angle. The deflection element 17 points in the assembly direction 16. The form-fit element 15 points counter to the assembly direction 16.
The form-fit element 15, the deflection element 17 and the main tool body 12 are formed in one piece. The entire main tool body 12 is designed in a tubular shape. At its end 19, the main tool body 12 has a free cut 20, which forms the deflection element 17 and the form-fit element 15. Herein the free cut 20 is formed by two incisions which extend substantially parallel to each other and which are introduced into the main tool body 12 from the end 19. The form-fit element 15 is formed by bending a portion of the free cut 20. Herein the form-fit element 15 is bent inward. It thus protrudes into an interior space 30 which is enclosed by the main tool body 12. The deflection element 17 is designed as that portion of the free cut 20 that remains substantially unaltered.
In an area in which the deflection element 17 is attached to the main tool body 12, the tool 10 has a material weakening 31. The material weakening 31 forms a predetermined breaking point. In the embodiment shown, the material weakening 31 is formed as a hole arranged between the two incisions that form the free cut 20. However, it is in principle also possible to design the free cut 20 by means of incisions tapering toward each other, as a result of which a material weakening can likewise be achieved. Moreover, it is also conceivable that the main tool body 12, in the area in which the main tool body 12 merges into the deflection element 17, has a wall thickness that is reduced as compared to the rest of the main tool body 12. The reduced wall thickness can be obtained, for example, by introducing a groove in this area, which groove is advantageously formed by punching.
By bending out the form-fit element 15, the free cut 20 forms a recess 21 that extends as far as the end 19 of the main tool body 12. A corresponding drive element 32 of the tool attachment unit 13 can engage in the recess 21, as a result of which a portion of the free cut 20 is provided for torque transfer.
The main tool body 12 further comprises a recess 33, which is intended only for torque transfer. The recess 33 is arranged axially overlapping the free cut 20. With respect to the rotation axis 22, the further recess 33 is arranged to be situated opposite the free cut 20.
The plug-on element 23 has a substantially cylindrical basic shape. The plug-on element 23 has an external diameter that is at least slightly smaller than an internal diameter of the main tool body 12. In order to implement the form-fit engagement element 24, which is provided for the form-fit element 15 of the fixing unit 14 of the main tool body 12, the plug-on element 23 comprises a recess 26. The recess 26 is designed in the form of a slit. The plug-on element 23 itself is designed as a hollow-body element.
The form-fit engagement element 24 forms a contact face 25 for the form-fit element 15. The contact face 25 is designed as an oblique face in relation to a cross-sectional face, i.e. a surface that extends perpendicularly with respect to the rotation axis 22. The contact face 25 is tilted at an angle 34 of approximately 15 degrees with respect to the cross-sectional face. Opposite the contact face 25, the form-fit engagement element 24 has a second face which, when the recess 26 is designed in the form of a slit as implemented, extends substantially parallel to the contact face 25. In principle, the recess 26 can also be designed in the shape of a wedge, as a result of which the contact face 25 and the opposite face would be at an angle to each other.
The form-fit engagement element 24 forms an undercut with respect to a radial direction, i.e. a direction perpendicular to the rotation axis 22. The contact face 25 is designed as a partial cut face through the plug-on element 23. The contact face 25 is thus designed as a surface in the shape of part of a circle. It comprises a base line, which extends through the plug-on element 23, and a surface line, which is defined by a jacket surface 35 of the plug-on element 23.
The base line of the contact face 25 extends perpendicularly with respect to the rotation axis 22. Starting from the base line, the level lines of the contact face 25 enclose, with the rotation axis 22, an angle different than 90 degrees. Starting from the base line, the contact face 25 is herein inclined in the direction of the assembly direction 16, wherein the base line can be regarded as an axis for the inclination of the contact face 25. Thus, seen from the outside in a radial direction, the contact face 25 forms an undercut in which the form-fit element 15 engages in the assembled state. A tensile force, which is taken up by the contact face 25, and which can be transferred via the form-fit element 15, produces a holding force that makes it impossible or at least difficult for the form-fit element 15 to slip out of the form-fit engagement element 24.
To make it easier for the tool 10 to be plugged on, the plug-on element 23 of the tool attachment unit 13 has an oblique face 36, which is provided for deflecting the form-fit element 15 in relation to the main tool body 12 when the tool 10 is mounted on the tool attachment unit 13. To form the oblique face 36, the plug-on element 23 has, in a partial area, a diameter that increases continuously in the direction of the main body 38 starting from a tip 37. Herein the oblique face 36 is arranged to be aligned with the form-fit engagement element 24 in relation to the rotation axis 22.
To release the tool 10 from the tool attachment unit 13, the plug-on element 23 has a recess 39. The recess 39 passes completely through the plug-on element 23 along a direction that is oriented perpendicularly with respect to the rotation axis 22. Herein the recess 39 is introduced into the plug-on element 23 in the area of the oblique face 36.
In order to limit a depth up to which the tool 10 can be plugged on, the tool-fixing device 11 has an axial bedstop 40. The main body 38 forms a stop face for the axial bedstop 40. The bedstop 40 and the plug-on element 23 are formed in one piece with the main body 38. To form the bedstop 40, the tool-fixing device 11 has an increased diameter in an area adjacent to the plug-on element 23 in the axial direction.
In order to transfer torques, the tool attachment unit 13 comprises the drive element 32, which is provided to engage in the recess 21 formed at the main tool body 12 by the free cut 20. The tool attachment unit 13 further comprises a drive element 41, which is provided to engage in the recess 33. The drive element 32 is arranged on the same side of the plug-on element 23 as the form-fit engagement element 24. The drive element 41 is arranged on that side of the plug-on element 23 which is situated opposite the form-fit engagement element 24 in relation to the rotation axis 22. The drive element 32 is formed in one piece with the main body 38. The drive element 41 is designed as an additionally inserted pin connected rigidly to the plug-on element 23. In principle, however, any desired configurations are conceivable for the drive elements 32, 41. In particular, it is also possible to omit the drive element 32 and the corresponding recess 33 at the main tool body 12.
The tool-fixing device 11 further comprises a drive attachment unit 27, which is designed for releasable connection to the drive device. The tool attachment unit 13 and the drive attachment unit 27 are aligned coaxially with each other. The tool attachment unit 13 and the drive attachment unit 27 have different designs. The tool-fixing device 11 is thus implemented as an adapter, which is provided for establishing a connection between a drive of the drive device and the tool 10.
To fasten the tool 10 to the tool-fixing device 11, the main tool body 12 of the tool 10 is first of all plugged onto the plug-on element 23 of the tool attachment unit 13. The form-fit element 15 is deflected by the linear movement along the assembly direction 16, as a result of which the deflection element 17, which is initially arranged almost parallel to the jacket surface 35 of the main tool body 12, is also deflected outward. As soon as the form-fit element 15 is axially level with the form-fit engagement element 24, the form-fit element 15 engages in the form-fit engagement element 24. By means of a tensile force applied to the tool 10, the form-fit element 15 is brought into complete engagement with the form-fit engagement element 24.
To release the tool 10, the deflection element 17 is bent out, toward an outside, using a suitable tool, which is guided through the recess 33 in the main tool body 12 and through the recess 39 in the plug-on element 23. Bending-out causes a plastic deformation in the area of the material weakening 31, as a result of which the connection between the main tool body 12 and the deflection element 17 is weakened. After only a few uses, but preferably after just one use, this connection is weakened so that it breaks, as a result of which the tool 10 can then no longer be fixed axially on the tool-fixing device 11.
In an alternative embodiment not shown in detail, the tool-fixing device 11 comprises a mechanism which is provided for de-activating, with respect to a torque-proof connection of the main tool body 12, the at least one drive element 32, 41. When the mechanism is actuated, the respective drive element 32, 41 is countersunk into the plug-on element 23, as a result of which the main tool body 12 can be turned on the plug-on element 23. This turning has the effect that the form-fit element 15 is rotated sideways out of the form-fit engagement element 24, as a result of which the deflection element 17 is deflected outward at the same time. The deflection has the effect that the material weakening 31 is likewise weakened so that the deflection element 17 with the form-fit element 15 breaks off immediately or upon renewed insertion of the tool 10. After the tool 10 has been released from the tool-fixing device 11, the fixing unit 14 of the main tool body 12 is thus unusable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 049 244.2 | Oct 2010 | DE | national |
This application is a U.S. national stage application of PCT/EP2011/005358 filed on Oct. 25, 2011, and claims priority to, and incorporates by reference, German patent application No. 10 2010 049 244.2 filed on Oct. 25, 2010.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP11/05358 | 10/25/2011 | WO | 00 | 4/18/2013 |
