Trepan

Abstract

A ring saw has a tool holder (5) for guiding a ring saw blade in a cutting plane, a motor, a drive wheel (6), and a bearing seat (66). The tool holder has a guide roller (41) arranged on one side of the cutting plane and a guide roller (43) arranged on the opposite side of the cutting plane. The drive wheel is arranged in the cutting plane and is connected to the motor (30). The drive wheel is mounted in the bearing seat so that the drive wheel can rotate around a drive axis (60) perpendicular to the cutting plane. The bearing seat is mounted on a slider, the slider can move in a radial direction parallel to the cutting plane and the bearing seat can move parallel to the cutting plane. The slider is connected to an actuating rod by a connecting rod. The actuating rod can be actuated by a user. The user can move the slider by the actuating rod. The actuating rod has an open position and a closed position. In the open position, the drive wheel is at a certain distance from the ring saw blade and the contact between the guide roller and the ring saw blade is cancelled. In the closed position, the drive wheel is pressed against the ring saw blade.

Description

Technical Field

[0001] The invention relates to a ring saw. Background Art

[0002] The ring saw drives the ring saw blade eccentrically via a drive wheel. The eccentric drive requires guidance of the ring saw blade, which is achieved via rollers and wheels. In this case, high friction losses can occur between the rollers and the ring saw blade. In addition, changing the ring saw blade is laborious, especially because the drive wheel and rollers must be readjusted to obtain good guidance. Summary of the invention

[0003] According to one aspect of the invention, a ring saw has a tool holder for guiding a ring saw blade in a cutting plane, a motor, a drive wheel, at least one guide roller and at least one guide roller. To drive the ring saw blade, the drive wheel is arranged in the cutting plane and is coupled to the motor. The at least one guide roller is arranged on one side of the cutting plane and the at least one guide roller is arranged on the opposite side of the cutting plane. The ring saw has a bearing seat in which the drive wheel is mounted so that the drive wheel can rotate about a drive axis perpendicular to the cutting plane. The bearing seat is mounted on a slide which can be moved in a radial direction parallel to the cutting plane and thereby the bearing seat can be moved parallel to the cutting plane, the slide being connected to an actuating lever by means of a connecting rod, the actuating lever being actuable by a user, by means of which the user can move the slide, the actuating lever having an open position and a closed position, in which the drive wheel is at a distance from the ring saw blade and the tool holder is unlocked, wherein the contact of the guide roller with the ring saw blade is cancelled and the ring saw blade rests loosely on the guide roller, and in the closed position, the drive wheel is pressed against the ring saw blade and the guide roller is in contact with the ring saw blade, so that the tool holder is locked. The configuration with a movable drive wheel enables the removal and insertion of the ring saw blade without the use of tools.

[0004] The preferred embodiment has a bevel gear mechanism coupling the drive wheel to the motor. The bevel gear mechanism has a crown wheel connected to the drive wheel. The crown wheel is mounted in a bearing housing. The drive wheel and the crown wheel together form a movable unit. The bevel gear mechanism with the crown wheel is very insensitive to inaccurate positioning of the crown wheel. Therefore, good tolerance is achieved for ring saw blades with slightly different insertion widths.

[0005] The ring saw blade according to the invention has a flat annular support having a side and an outer circumference. One or more cutting elements are arranged along the outer circumference of the support. At least one annular groove is recessed into the side. The groove has a radial inner side and a radial outer side. The radial inner side is of conical design, and the cone describing the conical side has a half opening angle between 10 degrees and 30 degrees. The ring saw blade allows low-friction guidance by the inclined side. The guide roller can rotate approximately parallel to the axis of rotation of the ring saw blade and can rest on the groove during this process. In addition, the diameter of the guide roller can be greater than the width of the groove. The orientation of the guide roller and its possible diameter size have a decisive role in the low friction losses.

[0006] The radially outer portion preferably extends continuously below the descriptive cone envelope perpendicular to the inner portion, ie on the side facing the support, and extends through the point on the inner portion furthest from the side, ie the lowest point of said side. A cylindrical guide roller may rest on the inclined inner portion.

[0007] The profile of the ring saw blade may be asymmetrical. The outer side is preferably conical. The cone describing the conical side has a half angle of between 50 and 80 degrees. The asymmetrical shape ensures that the support is hardly weakened by reducing the cross section of the groove to a minimum.

[0008] According to one aspect of the invention, a ring saw has a tool holder for guiding a ring saw blade in a cutting plane, a motor, a drive wheel, at least one guide roller and at least one guide roller. In order to drive the ring saw blade, the drive wheel is arranged in the cutting plane and is connected to the motor. The at least one guide roller is arranged on one side of the cutting plane. The at least one guide roller is arranged on the opposite side of the cutting plane. The guide roller is mounted in a manner that it can rotate freely around the axis of rotation. The axis of rotation is inclined by 50 to 80 degrees relative to the cutting plane. The guide roller is inclined to be approximately parallel to the axis of rotation of the ring saw blade, but can still be located in the guide groove of the ring saw blade. In addition, the diameter of the guide roller can be greater than the width of the guide groove. The orientation of the guide roller and its possible diameter size play a decisive role in low friction losses.

[0009] According to one embodiment, the guide roller may have at least one rolling element having a rotationally symmetrical side surface. In a preferred embodiment, the guide roller has two or more concentric rolling elements. The radius of a first rolling element of the rolling elements may be smaller than the radius of a second rolling element of the rolling elements. The first rolling element of the rolling elements is arranged closer to the cutting plane along the axis of rotation relative to the second rolling element of the rolling elements. The section of the first rolling element closest to the cutting plane and the section of the second rolling element closest to the cutting plane are preferably located in the same plane. The two closest sections are preferably engaged in the guide groove of the ring saw blade.

[0010] In one embodiment, a first one of the rolling elements is mounted on a second one of the rolling elements.The required bearing is only subject to the rotational speed of the smaller rolling element relative to the larger rolling element, and need not be subject to the much higher absolute rotational speed relative to the housing.

[0011] The smaller rolling elements rotate at a high absolute rotational speed relative to the housing, resulting in high stresses on the bearings. Mounting on the larger rotating rolling elements reduces the relative rotational speed of the smaller rolling elements acting on the bearings.

[0012] One embodiment envisages that the rotational axes of the guide rollers and of the guide rollers lie in a plane perpendicular to the cutting plane.

[0013] In a preferred embodiment, the axis of rotation of the guide roller is inclined relative to the cutting plane. The guide roller may be conical. The peripheral speed of the rolling side surface of the guide roller increases from the end closest to the axis of rotation to the end farther from the axis of rotation. The increase preferably corresponds approximately to a higher peripheral speed of the areas of the ring saw blade that are further out than the areas that are closer to the axis of rotation. As a result, the friction of the guide roller on the ring saw blade can be reduced.

[0014] According to one aspect of the invention, a ring saw has a tool holder for guiding a ring saw blade in a cutting plane, a motor and a drive wheel, the drive wheel being arranged in the cutting plane to drive the ring saw blade and being connected to the motor. The drive wheel is mounted in a bearing seat so that the drive wheel can rotate around a drive axis perpendicular to the cutting plane. A guide roller is arranged on one side of the cutting plane to guide the ring saw blade from this side. A guide roller is arranged on the opposite side of the cutting plane to guide the ring saw blade from this opposite side. The guide roller is arranged in a cover that can be pivoted relative to the cutting plane. By opening the cover, the user can access the tool holder. At the same time, the guide roller rises from the ring saw blade, canceling the locking of the ring saw blade. The user can replace the ring saw blade without using tools.

[0015] In one embodiment, the tool holder can have a receiving space for receiving a ring saw blade, wherein the cover covers the receiving space. The drive wheel, the guide roller and the guide roller can be arranged in the receiving space.

[0016] In one embodiment it is envisaged that the portion of the side surface of the guide roller facing the cutting plane extends parallel to the cutting plane.

[0017] In a preferred embodiment, the cover can be locked on the housing. The cover can be opened and closed by an actuating lever.

[0018] In another preferred embodiment, the drive wheel is movable in the cutting plane and the movement of the cover and the drive wheel is synchronized by a mechanism. The actuating lever may have an open position and a closed position. The cover and the drive wheel are coupled to the actuating lever in such a way that in the closed position, the cover is closed and the drive wheel is pressed against the ring saw blade; in the open position, the cover is open and the drive wheel is at a distance from the ring saw blade. The user does not need to laboriously adjust or align when changing the ring saw blade.

[0019] One embodiment contemplates that, in going from the closed position to the open position, the actuating lever first moves the drive wheel and then opens the cover.

[0020] In one embodiment, the ring saw has a mechanism that first moves the drive wheel and then opens the cover in response to movement of the actuating rod from a closed position to an open position. In the open position, the cover is open and the drive wheel is at a certain distance from the ring saw blade. In the closed position, the cover is closed and the drive wheel is pressed against the ring saw blade.

[0021] According to one aspect of the invention, a ring saw has a tool holder for guiding a ring saw blade. The tool holder is arranged in a receiving space. A drive wheel is used to drive the ring saw blade, is arranged in a cutting plane and is connected to a motor. A guide roller is arranged on one side of the cutting plane to guide the ring saw blade from one side. An outlet is provided pointing to the guide roller. The guide roller is cleaned with water and then the ring saw blade is water-cooled.

[0022] A preferred embodiment envisages that guide rollers are arranged upstream of the receiving space in the flow direction of the water flushing system. The guide rollers can have cylindrical rolling elements for engagement in the guide grooves of the ring saw blade. The outlet is directed toward the side surface of the rolling element or toward a surface facing away from the cutting plane. Before the water reaches the ring saw blade that is contaminated with dust or sludge, the water first comes into contact with the side surface.

[0023] One embodiment envisages that the rolling element is arranged in a container that is sealed from the housing and has an opening facing the receiving space. A section of the rolling element can be arranged in the receiving space, and a section of the rolling element can be arranged in the container. The opening is preferably smaller than the cross section of the rolling element.

[0024] In one embodiment, the outlet is arranged in the container. The channel connected to the outlet may have a spiral portion extending around the rotation axis of the guide roller. Water may be guided onto the guide roller in the direction of rotation of the guide roller. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following description explains the invention with reference to exemplary embodiments and the accompanying drawings, in which:

[0026] Figure 1 A trephine and trephine blade are shown;

[0027] Figure 2 A cross section along plane II-II is shown;

[0028] Figure 3 Shows the groove profile of the ring saw blade, section III-III;

[0029] Figure 4 An alternative groove profile for a trephine saw blade is shown;

[0030] Figure 5 A section through the guide rollers and guide rolls along plane VV is shown;

[0031] Figure 6 A section along plane VV is shown with the cover open;

[0032] Figure 7 The drive is shown;

[0033] Figure 8 The mechanism for removing and locking the trepan saw blade in the closed position is shown;

[0034] Fig. 9 A mechanism for removing and locking the ring saw blade in an intermediate position is shown;

[0035] Fig.10 The mechanism for removing and locking the trepan saw blade in the open position is shown;

[0036] Fig.11 A water director is shown, a section along plane VV.

[0037] Unless stated otherwise, identical or functionally identical elements are denoted by the same reference symbols in the figures. DETAILED DESCRIPTION

[0038] exist Figure 1Schematic illustrations of a ring saw blade 1 and a ring saw 2 are shown in a plan view of and in a vertical section along plane II-II. The ring saw blade 1 has the form of a flat annular disk, with a cutting element 3 located radially on the outside. The form defines an axis of rotation 4, about which the ring saw blade 1 rotates during use. The ring saw 2 has a tool holder 5, on which the ring saw blade 1 is mounted so as to be rotatable about said axis of rotation 4. It is driven eccentrically relative to the axis of rotation 4 by a drive wheel 6, which abuts against the annular inner circumference of the hollow ring saw blade 1.

[0039] Based on the intended use and the cylindrical symmetry of the ring saw blade 1, the description of the ring saw blade 1 introduces a rotation axis 4 and a cutting plane E oriented perpendicular to the rotation axis 4. The intersection of the rotation axis 4 and the cutting plane E coincides with the geometric center or center of gravity of the ring saw blade 1. The cutting plane E corresponds to the plane in which the ring saw blade 1 cuts a workpiece, a substrate, etc. In the following description, axial and radial direction indications are related to the rotation axis 4, unless explicitly indicated otherwise. Radially inner elements are arranged closer to the rotation axis 4 than radially outer elements, which, in contrast, are arranged closer to the outer circumference of the ring saw blade 1.

[0040] The ring saw blade 1 has a flat support 7 in the form of a hollow circle. In the radial direction, the support 7 in the form of a hollow circle is delimited by an outer circumference 8 and an inner circumference 9. The outer circumference 8 and the inner circumference 9 are concentric and symmetrical with respect to the rotation axis 4. The inner circumference 9 is circular, while the outer circumference 8 is preferably circular or approximately circular. The distance of the outer circumference 8 from the rotation axis 4 corresponds to the outer radius 10. Similarly, the distance of the inner circumference 9 relative to the rotation axis 4 is described by the inner radius 11. The width of the support 7 refers to the difference between the outer radius 10 and the inner radius 11. The ratio of the inner radius 11 to the outer radius 10 is preferably greater than 50%, for example greater than 66%. A front side 14 in the form of a hollow circle and a rear side 15 in the form of a hollow circle delimit the support 7 along the rotation axis 4. The rear side 15 is preferably flat and unstructured. The rear side 15 can be parallel to the cutting plane E. The front side 14 is preferably substantially flat and preferably parallel to the cutting plane E. The height 16 of the flat support 7 , ie its dimension along the axis of rotation 4 , is significantly smaller than the radius.

[0041] The front side 14 of the support 7 has a substantially flat main surface 17 extending typically parallel to the cutting plane E, and at least one annular (guide) groove 18. The guide groove 18 is concentric with the inner circumference 9 of the support 7, i.e. the guide groove extends at a constant distance around the axis of rotation 4. The guide groove 18 is of substantially rotationally symmetrical design. The contour of the guide groove 18 is constant around the axis of rotation. The contour represents the contour of the guide groove 18 along a plane containing the axis of rotation 4 (e.g., as in Figure 31 ). The profile of the guide groove 18 shown has a radially inner guide side portion 19, a radially outer side portion 20 and a groove bottom 21 arranged between the guide side portion 19 and the outer side portion 20. The groove bottom 21 forms the deepest area of ​​the guide groove 18, i.e. the groove bottom 21 is the area of ​​the groove 18 closest to the rear side 15. The depth 22 of the guide groove 23 represents the distance between the groove bottom 21 and the main surface 17 of the front side 1. The illustrative groove bottom 21 is flat and parallel to the cutting plane E. In other embodiments, the groove bottom 21 can have a circular line without extension, wherein the guide side portion 19 and the outer side portion 20 are in contact with each other. The guide side portion 19 and the outer side portion 20 each extend from the main surface 17 to the groove bottom 21.

[0042] The guide side 19 rises in the axial direction from the groove bottom 21 to the main surface 17 in the radial direction toward the rotation axis 4. The guide side 19 is conical. The descriptive cone 24 is symmetrical with respect to the rotation axis 4, and the tip of the cone is located on the same side of the cutting plane E as the front side 14 and the guide groove 18. The half angle 25 of the cone 24 is less than 30 degrees, preferably less than 25 degrees, and greater than 10 degrees, preferably greater than 15 degrees. However, the guide side 19 is steep but not perpendicular with respect to the cutting plane E.

[0043] The outer side 20 descends in the axial direction from the main surface 17 of the front side 14 in the radial direction towards the axis of rotation 4 to the groove bottom 21. The side 20 extends continuously below or on the cone 26 defined by the guide side 19 and the depth 22 of the guide groove 18. This delimiting cone 26 is perpendicular to the conical guide side 19 and passes through the lowest point of the guide side 19. In this context, "below" means that the side 20 is on the same side of the cone 26 as the rear side 15. Therefore, the cone 26 passes through the cavity of the guide groove 18 and enters the support 7 only at the guide side 19 in the direction of the axis of rotation 4. The guide side 19 is located continuously above the cone envelope. The opposite side 20 can be implemented in various ways. The side 20 preferably descends monotonically. In a preferred embodiment, the opposite side 20 is in the form of a cone. The descriptive cone is symmetrical with respect to the axis of rotation 4; the tip of the cone is located on the side of the support 7 opposite to the front side 14. The half angle 27 of the cone is greater than 50 degrees, preferably greater than 60 degrees, and preferably less than 75 degrees, for example less than 70 degrees. The outer side 20 is therefore significantly longer than the guiding side 19 .

[0044] The guide grooves 18, 23 have a highly asymmetric profile. The sum of the half angles 25, 27 of the cones describing the guide side 19 and the opposite side 20 is preferably greater than 90 degrees, but preferably less than 120 degrees. The guide side 19 occupies only a small proportion of the width 28 of the guide groove 18 (i.e. its radial dimension), for example less than 20%. The other side 19 and the groove bottom 21 occupy most of the width 28. The width 28 is at least three times, for example at least four times, the depth 22 of the guide groove 18 (i.e. its dimension along the axis of rotation 4). An embodiment with elongated opposite sides 20 is preferred because such a hollow profile has a relatively small cross-sectional area. As a result, the support 7 is more stable. This applies in particular to the case where two or more guide grooves are provided. In another embodiment, the groove bottom occupies at least three quarters of the groove width. The other side can be described by a cone with a similar angle of opening as the guide side, see Figure 4 The front side 14 can have two guide grooves 18, 23. The two guide grooves 18, 23 are concentric with each other. In the embodiment shown, the two guide grooves 18, 23 have the same contour. The guide grooves 18, 23 differ only in their radius.

[0045] The inner circumference 9 of the support 7 serves as a running surface 29. The running surface 29 may be obtuse or rounded, or preferably may have a trapezoidal cross section. The running surface 29 has the shape of a rotating body, whose axis of symmetry coincides with the axis of rotation 4.

[0046] When a substrate is cut with the ring saw blade 1, the ring saw blade 1 is inserted into the substrate in the cutting plane E. The cutting element 3 is arranged in the cutting plane E along the outer circumference 8 of the support 7. The cutting element 3 protrudes from the support 7 in a radial direction. In addition, the cutting element 3 also protrudes from the support 7 in two axial directions. Therefore, the cutting element 3 is thicker than the support 7, i.e. the cutting element has a larger dimension along the rotation axis 4. The notch cut by the cutting element 3 is wide enough to enable the support 7 to be inserted into the notch. The cutting element 3 can be abrasive or can form chips. For example, the cutting element contains diamond particles or similar hard particles embedded in a matrix. The support 7 is preferably made of steel.

[0047] The ring saw 2 is preferably a handheld power tool or a portable power tool. The ring saw 2 has a tool holder 5 for guiding the ring saw blade 1. The motor 30 is used to drive the ring saw blade 1 guided in the tool holder 5. The motor 30 is arranged in a housing 31. A handle 32 for holding and guiding the ring saw 2 during sawing is arranged on the housing 31. The ring saw 2 preferably has two handles or handles that can be grasped with both hands. The illustrative handle is designed as a ring. The handle 32 is arranged on the housing 31 of the ring saw 2.

[0048] The user can lock and unlock the tool holder 5 without tools to insert or remove the ring saw blade 1. The tool holder 5 is based on a plurality of rollers, which bear against the opposite sides 14, 15 of the ring saw blade 1. The tool holder 5 has a receiving space 33 for the ring saw blade 1, which is preferably covered by a cover 34. The user can remove the cover 34 from the housing 31 or rotate it open, pivot it, etc. relative to the housing 31. The opening and closing of the cover 34 and the unlocking and locking of the tool holder 5 can be achieved, for example, by an actuating lever 35.

[0049] The following description of the tool holder 5 relates to the locked position ( Figure 5 ).

[0050] The tool holder 5 has a receiving space 33 for the ring saw blade 1. The receiving space 33 is preferably surrounded by a bottom 36 and a top 37 along the rotation axis 4 and by a side wall 38 in the radial direction. The bottom 36 is arranged on one side of the cutting plane E, while the top 37 is arranged on the opposite side. The bottom 36 and the top 37 extend substantially along the cutting plane E. The side wall 38 extends around the rotation axis 4 in the circumferential direction and can be of cylindrical design. The receiving space 33 has an inlet opening 39 and an outlet opening through which the ring saw blade 1 can enter and leave the receiving space 33. The bottom 36 can be formed by the outer surface of the housing 31. The top 37 can be formed by the inner surface of the cover 34. The receiving space 33 is preferably designed to be dustproof and waterproof relative to the housing 31 to protect the electric motor 30, the transmission 40, etc. of the ring saw 2 from sawdust or water introduced by the ring saw blade 1.

[0051] The tool holder 5 of the trepanation 2 is arranged in the receiving space 33. The tool holder 5 is based on guide rollers 41, 42 and guide rollers 43, 44. The guide rollers 41, 42 are arranged on one side of the cutting plane E and the guide rollers 43, 44 are arranged on the opposite side of the cutting plane E. The illustrative guide rollers 41, 42 protrude into the receiving space 33 relative to the bottom 36. The illustrative guide rollers 43, 44 protrude into the receiving space 33 starting from the top 37. The guide rollers 41, 42 engage in the guide grooves 18, 23 of the trepanation saw blade 1. The guide rollers 43, 44 bear against the preferably smooth rear side 15 of the trepanation saw blade 1. The illustrative trepanation 2 has two guide rollers 41, 42, which are arranged offset in the circumferential direction 45 about the rotation axis 4. Other embodiments have only one guide roller or have up to four guide rollers. The guide rollers 43, 44 are preferably arranged opposite the guide rollers 41, 42, i.e. at the same angular position around the axis of rotation 4. The pair comprising the guide roller 41 and the opposing guide roller 43 sandwiches the ring saw blade 1 therebetween. The axial distance between the guide roller 41 and the guide roller 43 corresponds to the thickness 16 of the set or inserted ring saw blade 1.

[0052] The guide roller 41 has at least one rolling element 46, 47, which is mounted rotatably about an axis of rotation 48. The axis of rotation 48 and the rolling element 46 are inclined relative to the cutting plane E so that the part of the rolling element 46 facing the axis of rotation 4 engages in the guide groove 18. The part of the rolling element 46 facing away from the axis of rotation 4 is correspondingly spaced apart from the ring saw blade 1 in the axial direction. The rolling element 46 has a rotationally symmetrical side surface 49. The illustrative side surface 49 has a cylindrical shape. The side surface 49 abuts against the guide groove 18 of the ring saw blade 1. The driven ring saw blade 1 moves the rolling element 46 and also the guide roller 41. The inclined alignment of the guide roller 41 enables the guide roller 41 to be driven by the ring saw blade 1 without friction or with little friction. The low friction increases the efficiency of the ring saw 2 and the life of the guide roller 41.

[0053] The guide roller 41 or the rolling elements 46, 47 of the guide roller 41 are mounted so that they can rotate about the rotation axis 48 in a forceless and low-friction manner. Of course, the guide roller 41 is not driven directly by the motor 30. However, the guide roller 41 is able to move by the ring saw blade 1. The large ratio of the diameter of the ring saw blade 1 to the diameter of the rolling elements 46 enables the rolling elements 46 to have a high rotation speed. Therefore, the rolling elements 46 are preferably mounted in low-friction bearings 50, such as ball bearings, in order to avoid friction losses caused by the fast-rotating guide roller 41. The rolling elements 46 are mounted in ball bearings, for example.

[0054] As mentioned above, the rotation axis 48 is inclined relative to the cutting plane E. The rotation axis 48 may be located in the same plane as the rotation axis 4. In the illustrated embodiment, the rotation axis 4 and the rotation axis 48 are arranged in an oblique manner. The rotation axis 4 and the rotation axis 48 do not intersect each other and are not parallel. The point on the rotation axis 48 closest to the rotation axis 4 is located on the same side of the cutting plane E as the guide roller 41. Starting from the guide roller 41, the rotation axis 48 extends in a radial direction toward the rotation axis 4 and at the same time away from the cutting plane E and the front side 14 of the ring saw blade 1. The inclination of the rotation axis 48 relative to the cutting plane E is converted into an inclination of the rolling element 46, which is at a greater distance from the cutting plane E as the distance from the rotation axis 4 increases. The inclination 51 of the rotation axis 48 relative to the line perpendicular to the cutting plane E is less than 30 degrees, preferably less than 25 degrees, and greater than 10 degrees, preferably greater than 15 degrees. In the case of the illustrative cylindrical rolling element 46 , the inclination angle 51 is equal to the inclination of the leading side 19 of the ring saw blade 1 provided for the ring saw 2 .

[0055] The number of rolling elements 46, 47 matches the number of guide grooves 18, 23 of the ring saw blade 1 provided. The preferred embodiment shown has two rolling elements 46, 47. Other embodiments have one rolling element 46 or up to four rolling elements. The rolling elements 46, 47 are arranged coaxially and are mounted so as to be rotatable about the same axis of rotation 48. The radii of the rolling elements 46, 47 or their side surfaces 49 are different. The inner guide groove 18 of the inserted ring saw blade 1 is further away from the axis of rotation 48 than the outer guide groove 23. Therefore, the radius of the rolling element 46 associated with the inner guide groove 18 is greater than the radius of the rolling element 47 associated with the outer guide groove 23. The smaller rolling element 47 associated with the inner guide groove 18 or at least its side surface is arranged offset relative to the larger rolling element 46 associated with the outer guide groove 18 along the axis of rotation 48 in the direction of the cutting plane E. The offset between the smaller rolling element 47 and the larger rolling element 46 is determined so that the parts thereof facing the axis of rotation 4 are at the same distance from the cutting plane E. The offset is defined trigonometrically by the difference between the radius and the inclination angle 51. The two rolling elements 46, 47 preferably engage in the guide grooves 18, 23 at the same depth or approximately the same depth.

[0056] Due to the smaller radius of the smaller rolling element 47 and the greater circumference of the outer guide groove 23, the smaller rolling element rotates significantly faster than the larger rolling element 46. Therefore, the smaller rolling element 47 is preferably not mounted directly in the housing 31. In a preferred embodiment, the smaller rolling element 47 is mounted on the larger rolling element 46. The bearings, such as ball bearings, are only stressed in terms of the speed difference between the two rolling elements. The larger rolling element 46 is mounted in bearings 50 fixed in the housing 31. During sawing, the ring saw blade 1 is supported via its guide groove 18 in the radial direction 68, i.e. in the cutting plane E, on the guide rollers 41. The guide rollers 41 transmit the forces directly to the housing 31.

[0057] The illustrative guide roller 41 is mounted in the housing 31. The rolling elements 46, 47 protrude into the receiving space 33. The rolling elements 46, 47 are exposed to dust and water. In order to ensure that dust and water do not penetrate into the housing 31, at least the rolling elements 46, 47 of the guide roller 41 are isolated from the housing 31. The rolling element 46 is arranged in a container 53, which is sealed off from the housing 31 and is open toward the receiving space 33. For example, the container 53 or the interior of the container 53 is of cylindrical design and is formed coaxially with the axis of rotation 48 of the rolling element 46. The container 53 has an opening 54, which faces the receiving space 33 and through which the rolling elements 46, 47 enter the receiving space 33. The opening 54 is located in the same plane as the bottom 36. The rolling elements 46, 47, which are preferably inclined relative to the cutting plane E and the bottom 36, can be arranged completely or partially in the receiving space 33. For example, only the section of the rolling element 46 that is closer to the cutting plane E protrudes into the receiving space 33 through the opening 54. This section is in contact with the ring saw blade 1. The remaining section can be shielded from the receiving space 33 by the bottom 36. The associated opening 54 in the container 53 is, for example, notch-shaped or circle-segment-shaped to match the intersection profile of the inclined rolling element 46 with the plane of the bottom 36. The volume of the container 53 is designed to be as small as possible to ensure that no dust, dirty water, etc. accumulates therein. For example, the volume of the container 53 does not exceed three times, for example not more than two times, for example not more than one and a half times, the volume of the rolling elements 46, 47 of the guide roller 41. The diameter of the container is approximately equal to the diameter of the larger rolling element 46, for example, not more than 30% larger.

[0058] The guide roller 43 has a rolling element 55 which is mounted so as to be movable about an axis of rotation 56 ( Figure 5) rotates. The rolling element 55 has a cylindrical or preferably conical side surface 57. At least in operation or when the tool holder 5 is locked, the side surface 57 is aligned parallel to the cutting plane E. The ring saw blade 1 lies on the side surface 57 parallel to the cutting plane E or is supported by the side surface 49. The rotation axis 57 is arranged in a manner that is essentially radially oriented relative to the rotation axis 4. Therefore, the rolling element 55 can roll on the rotating ring saw blade 1 with little friction. Similar to the guide roller, the guide roller 43 is mounted in a low-friction and force-free manner. The preferred rolling element 55 has a conical side surface 55. The radius of the rolling element 55 decreases with decreasing distance from the rotation axis 4. The ratio of the radius of the rolling element 55 to the distance from the rotation axis 4 along the rotation axis 56 is preferably constant or approximately constant. The deviation from the average value of this ratio is less than 2%. The side surface 57 is described by a cone, the half opening angle of which is, for example, 2 degrees to 5 degrees. The inclination angle 58 of the rotation axis 57 relative to the cutting plane E is equal to the half opening angle. The rotation axis 57 of the guide roller 43 is preferably located in the same plane as the rotation axis 48 of the opposite guide roller 41. This plane is also perpendicular to the cutting plane E or parallel to the rotation axis 4. Even if the side surfaces of the guide rollers 41 and 43 are inclined relative to each other, there are only slight shear forces, if any, between the guide side 19 and the rear side 15 due to the same orientation of the rotation axes.

[0059] In the preferred embodiment shown, the tool holder 5 has two pairs of guide rollers 41 and guide rollers 43. The rotation axes 48 of the guide rollers 41 and the rotation axes 57 of the guide rollers 43 of each pair lie in the same plane. The two planes intersect at a line K, which is parallel to the rotation axis 4. The line K can lie on the rotation axis 4 or can be offset relative to the rotation axis 4. This reflects the ability of this ring saw 2 to accept ring saw blades 1 of different diameters. Since the position of the rotation axis 4 is defined by the guide groove 18 of the ring saw blade 1, the position of the rotation axis 4 relative to the ring saw 2 is only specified within the range of the ring saw blade 1 provided. Nevertheless, the rotation axis 4 is a well-defined direction indicating reference.

[0060] The tool holder 5 can be unlocked without tools in order to remove the trepanning saw blade 1. According to one embodiment, it is conceivable that the guide roller 43 can be moved away from the cutting plane E and, if applicable, from the inserted trepanning saw blade 1 in order to cancel the fixation along the rotation axis 4. For example, Figure 6Schematically shown, the guide roller 43 is suspended on the inner side of the cover 34. A rotary bearing 59 can be fixed to the cover 34, in which the guide roller 43 is rotatably mounted about the rotation axis 56. When the cover 34 is closed, the guide roller 43 rests on the ring saw blade 1 and the tool holder 5 is locked, as described above. When the cover 34 is opened, the guide roller 43 moves away from the cutting plane E and, where applicable, from the inserted ring saw blade 1. In the exemplary embodiment, the guide roller 43 pivots together with the cover 34 relative to the cutting plane E. The tool holder 5 is unlocked so that the ring saw blade 1 can be removed. A releasable lock is preferably provided, which prevents an accidental opening of the cover 34 and an associated unlocking of the tool accessories.

[0061] The drive of the trephine saw 2 includes a drive wheel 6, an illustrative electric motor 30, and a coupling of the electric motor 30 to the drive wheel 6 ( Figure 7 ) of the ring saw blade 1. Other motors (e.g. internal combustion engines) can be used instead of the electric motor 30. The drive wheel 6 is arranged in the cutting plane E and is eccentric with respect to the rotation axis 4. The drive axis 60 of the drive wheel 6 is offset with respect to the rotation axis 4. The drive axis 60 and the rotation axis 4 are preferably parallel. The drive wheel 6 rolls on the running surface 29 of the ring saw blade 1 (i.e. on the inner circumference 9 of the support 7). The diameter of the drive wheel 6 is correspondingly smaller than the inner radius 11 of the ring saw blade 1 provided for the ring saw 2. The transmission 40 can include various components for adjusting the rotation speed or torque, a safety clutch, etc.

[0062] The drive wheel 6 is preferably movable in the cutting plane E in order to make it easier to remove the ring saw blade 1 from the tool holder 5. By having an input-side pinion 61 and an output-side crown wheel 62 ( Figure 7 ) can achieve this movement. The crown wheel 62 is characterized by teeth 63 protruding from a base plate 64 along the drive axis 60. The teeth 63 are arranged around a cavity that is rotationally symmetrical (e.g. cylindrical) with respect to the drive axis 60. The teeth 63 can be cylindrical or prismatic or some other shape. In a preferred embodiment, the teeth 63 have a prismatic shape, whose triangular prismatic base surface is oriented tangential to the circumference of the crown wheel 62 or to some other circle around the drive axis 60. The drive wheel 6 and the crown wheel 62 are rotatably mounted in a bearing 65 around the drive axis 60. The bearing seat 66 is mounted on a slide 67, which can be moved in a radial direction 68 parallel to the cutting plane E. The slide 67 can move parallel to the axis 69 of the input side pinion 61. The slide 67 can be connected to the actuating rod 35, for example, by a connecting rod 70, by which the user can move the slide 67. A releasable lock is preferably provided, which secures the slide 67 in the locked position of the tool holder 5 .

[0063] The user can preferably lock the lock by actuating the lever 35 ( Figure 8) and unlock ( Fig.10 ) tool holder 5. The actuating lever 35 has a closed position ( Figure 8 ) and the open position ( Fig.10 ), in the closed position, the tool holder 5 is locked, and in the open position, the tool holder 5 is unlocked. In the open position of the actuating lever 35, the contact of the guide roller 43 with the ring saw blade 1 is cancelled. The contact of the drive wheel 6 with the ring saw blade 1 is preferably also cancelled. The ring saw blade 1 is loosely placed on the guide roller 41, from which the user can lift and remove the ring saw blade. When inserting a new ring saw blade 1, the user places the saw blade on the guide roller 41 by means of the guide groove 18. The guide groove 18 has ensured that the ring saw blade 1 is correctly aligned in the cutting plane E. In response to the closed position of the actuating lever 35, the guide roller 43 is in contact with the ring saw blade 1, so that the tool holder 5 is locked. In the closed position, the drive wheel 6 is preferably in contact with the ring saw blade 1.

[0064] The cover 34 preferably covers the tool holder 5 and the drive wheel 6. When the cover 34 is open, the user can access the guide rollers 41, the guide rollers 43 and the drive wheel 6, so that the user can remove or insert the ring saw blade 1. The cover 34 is preferably opened and closed according to the open position and the closed position by an actuating lever 35. The actuating lever 35 can operate the cover 34 and the tool holder 5 at the same time.

[0065] Combination Figures 8 to 10 An illustrative actuation lever 35 and mechanism 71 for operating the tool holder 5 and the cover 34 are illustrated. The actuation lever 35 is latched in the closed position. The force generated from the tool holder 5 or the cover 34 preferably pushes the actuation lever 35 to the closed position. In other embodiments, the actuation lever 35 can be fixed in the closed position by a user via a pin or the like.

[0066] In the closed position of the actuating lever 35, the cover 34 is closed. The cover 34 is suspended in a pivotable manner relative to the housing 31 about a pivot joint 72. The pivot joint 72 is arranged in a fixed position in the housing 31. The cover 34 preferably has a catch that prevents the cover 34 from being accidentally opened. The catch must be released by the actuating lever 35. In the closed position, the catch is locked by the actuating lever 35. An illustrative catch is based on a latch 73, which engages in a recess 74 in the housing 31. For example, the latch 73 is formed as a nose protruding in the radial direction 68 on the cover 34. The associated recess 74 in the housing 31 has a recess that is retracted in the radial direction 68 and is preferably designed to interlock with the nose. The latch 73 rests on the recess 74 in the circumferential direction around the pivot joint 72. Thereby the pivoting movement around this pivot joint 72 is constrained. The latch 73 can be moved away from the recess 74 in the radial direction 68. The latch 73 and the recess 74 no longer overlap in the circumferential direction around the pivot joint 72, and the constraint on the pivoting movement is eliminated. To this end, the cover 34 can, for example, move in the radial direction 68 in the housing 31. The cover 34 is attached to the pivot joint 72 via the slot 75. The slot 75 is preferably inclined relative to the radial direction 68. Therefore, the cover 34 can pivot around the pivot joint 72 and move a shorter distance in the radial direction 68. When the pivot joint 72 is located at the end of the slot 75 close to the buckle, the buckle is closed, and when the pivot joint 72 is located at the end of the slot 75 away from the buckle, the buckle is opened. The actuating rod 35 moves the cover 34 relative to the pivot joint 72 in such a way that the buckle is closed in the closed position of the cover 34. In the transition from the closed position to the intermediate position ( Fig. 9 ), the actuating lever 35 pulls the cover 34 against the radial direction 68 and pulls the latch 73 out of the recess 74. From the intermediate position to the open position, the cover 34 pivots about the pivot joint 72. The guide roller 43 pivots together with the cover 34 relative to the cutting plane E and, if applicable, relative to the ring saw blade 1.

[0067] The actuating lever 35 is coupled to the connecting rod 70 for moving the drive wheel 6. The movable drive wheel 6 can be preloaded into the unlocked position by a spring 76. The spring 76 presses on the connecting rod 70, for example, in the radial direction 68 towards the axis of rotation 4. In its open position, the actuating lever 35 releases the connecting rod 70, which moves into the unlocked position ( Fig. 9). During locking by the actuating lever 35, the auxiliary arm 77 of the actuating lever 35 pushes the connecting rod 70 against the radial direction 68. The auxiliary arm 77 is preferably decoupled from the connecting rod 70 until the guide roller 43 is no longer in contact with the ring saw blade 1. As a result, the guide groove 18 can rest against the guide roller 41 and align the ring saw blade 1 without interference from radial forces. Only when the guide roller 43 presses the guide groove 18 against the guide roller 43 and fixes it, radial forces are introduced by the drive wheel 6. The auxiliary arm 77 can be attached to the housing 31, for example, via a pivot joint 78. In response to its position, the actuating lever 35 pivots the auxiliary arm 77 to a different position.

[0068] The illustrative mechanism 71 includes a four-bar linkage that couples the actuating rod 35 to the cover 34 and the housing 31. The cover 34 and the auxiliary arm 77 are attached to fixed position joints 72, 78, for example. The actuating rod 35 is coupled to a joint 79 driven by the cover 34 and a joint 80 driven by the auxiliary arm 77.

[0069] In operation, the ring saw blade 1 is rinsed with water by means of the water rinsing system 81. The water cools the cutting element 3. Cooling is necessary in particular in the case of heat-sensitive diamond-containing cutting elements 3. A disadvantage of cooling with water is that the water mixes with the dust formed during the sawing process to form sludge. The sludge partially gets onto the ring saw blade 1 and is carried into the ring saw 2. The abrasive sludge leads to wear, in particular of the moving elements.

[0070] One embodiment of the ring saw 2 reduces wear by means of water. Water is supplied into the receiving space 33 of the tool holder 5 adjacent to the guide roller 41. The still clean water flows around the rolling elements 46, 47 of the guide roller 41. The mechanically high stress contact area can be kept free of sludge, or at least the entry of sludge into the contact area is reduced. In a preferred embodiment, the rolling elements 46, 47 are located upstream of the receiving space 33 in the direction of the water flow. Before the water comes into contact with dust, sludge, etc. in the receiving space 33, the water flows around at least a portion of the rolling element 46.

[0071] The water is provided by an external water supply 82. The water supply 82 may in particular comprise a water tank filled with water or flowing water from a public or private water supply network. The water supply 82 may collect, filter and recirculate the used water. The water is preferably under pressure, for example by raising the water tank position or by a booster pump. The trepan 2 has a water connection 83 for connecting to the water supply 82. A channel 84 in the trepan 2 delivers water from the water connection 83 to the receiving space 33 of the tool holder 5. The water preferably enters the receiving space 33 at or near the guide roller 41. For example, the water is supplied via a container 53 in which rolling elements 46, 47 are arranged. The water flows through the rolling elements 46, 47 into the receiving space 33. Therefore, the rolling element 46 is located upstream of the receiving space 33 in the direction of the incoming water flow. In particular, the water flows through the high stress side surface 49 into the receiving space 33. The outlet 85 of the channel 84 is directed, for example, to the side surface 49 of the rolling element 46 or to the surface 86 facing away from the receiving space 33. The channel 84 can have a spiral 87. The spiral 87 is arranged around the axis of rotation 48 of the guide roller 41. The spiral 87 can be arranged between a bearing seat 88 for the outer rolling element 46 and a wall of the container 53, for example.

Claims

1. A ring saw (2), comprising: a tool holder (5) for guiding the ring saw blade (1) in the cutting plane (E), Motor (30), a drive wheel (6) arranged for driving the ring saw blade (1) in the cutting plane (E) and coupled to the motor (30), a bearing seat (66) in which the drive wheel (6) is mounted so that the drive wheel can rotate about a drive axis (60) perpendicular to the cutting plane (E), The tool holder (5) has: - at least one guide roller (41) arranged on one side of the cutting plane (E) to guide the ring saw blade (1) from this side, - at least one guide roller (43) arranged on the opposite side of the cutting plane (E) to guide the ring saw blade (1) from the opposite side, It is characterized in that The bearing seat (66) is mounted on a slide block (67), which can move in a radial direction (68) parallel to the cutting plane (E) and thereby the bearing seat (66) can move parallel to the cutting plane (E). The slide block (67) is connected to an actuating rod (35) via a connecting rod (70), which actuating rod can be actuated by a user, and the user can move the slide block (67) via the actuating rod. The actuating rod (35) has an open position and a closed position. In the open position, the drive wheel is at a certain distance from the ring saw blade, and the tool holder (5) is unlocked, wherein the contact between the guide roller (43) and the ring saw blade (1) is cancelled, and the ring saw blade (1) is loosely placed on the guide roller (41). In the closed position, the drive wheel is pressed against the ring saw blade, and the guide roller (43) is in contact with the ring saw blade (1), so that the tool holder (5) is locked.

2. The ring saw (2) according to claim 1, characterized in that A bevel gear mechanism (40) couples the drive wheel (6) to the motor (30), wherein the bevel gear mechanism (40) has a crown wheel (62) connected to the drive wheel (6), and wherein the crown wheel (62) is mounted in the bearing seat (66).

3. The ring saw (2) according to claim 1 or 2, characterized in that A machine casing (31) and a pivotable cover (34), wherein the guide roller (43) is installed in the machine casing and the cover.

4. The ring saw (2) according to claim 3, characterized in that A mechanism (71) which, in response to movement of the actuating rod (35) from a closed position to an open position, first moves the drive wheel (6) and then opens the cover (34). In the open position, the cover is open and the drive wheel is at a distance from the ring saw blade. In the closed position, the cover is closed and the drive wheel is pressed against the ring saw blade.

5. The ring saw (2) according to claim 3, characterized in that: The guide roller (43) is suspended on the inner side of the cover (34), wherein a rotary bearing (59) is fixed to the cover (34) and the guide roller (43) is mounted in the rotary bearing so as to be rotatable about a rotation axis (56).

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