WO2011069720A1

WO2011069720A1 - Electrode grinding device

Info

Publication number: WO2011069720A1
Application number: PCT/EP2010/065343
Authority: WO
Inventors: Rolf Tamm
Original assignee: Rolf Tamm
Priority date: 2009-12-10
Filing date: 2010-10-13
Publication date: 2011-06-16
Also published as: EP2509749B1; DE102009044860B3; EP2509749A1

Abstract

The invention relates to a device (10) for machining welding electrodes, having a grinding wheel (20; 22) that is driven by a drive motor via a shaft (30) and that rotates in a hollow space in a housing (14, 16), wherein at least one opening (76, 78) is provided in the housing (14, 16) for guiding a welding electrode to be machined in a defined position in relation to the grinding wheel (20; 22). The device is characterized by a suction unit (140) that is connected to the device, via which suction unit particles generated during the grinding process can be suctioned from the housing (14, 16). The suction unit can comprise a water filter.

Description

Patent application

Electrode grinding device

Technical area

The invention relates to an apparatus for machining welding electrodes with a grinding wheel driven by a drive motor via a shaft, which rotates in a cavity in a housing, wherein in the housing at least one opening for guiding a welding electrode to be machined is provided in a defined position relative to the grinding wheel. The invention further relates to a kit for retrofitting such a device.

Welding electrodes are made of a very hard and high temperature resistant material like tungsten. There are welding electrodes of different cross section. The welding electrodes run out in a point or in a cutting edge. This form of welding electrodes depends on the particular application. The tips of the welding electrodes wear during operation.

Welding electrodes can be bought without bevel or with a prefabricated tip. After use, the tip or bevel is worn. The welding electrodes are then reground or discarded. This is very expensive because of the high quality material.

State of the art It is known to add welding electrodes on or nachschleleifen. This usually happens by hand on open grinding or cutting discs. This procedure is inaccurate and dangerous. Furthermore, devices with an open grinding wheel are known in which the welding electrodes are guided by a guide sleeve at a certain angle against the grinding wheel. Such devices are expensive. It is particularly expensive to convert the device to adapt to different types of welding electrodes or to different tip or cutting forms. In particular, an exchange of the guide sleeves is required. A device that can produce electrodes having a plurality (eg, 6) of different electrode diameters with a variety of different tip angles (eg, 4) and a variety of lengths is a valuable, cost-saving tool. From DE 100 10 520 AI a device for processing of welding electrodes with a grinding wheel is known. The grinding wheel runs in a grinding wheel housing. The device further has a housing attachment, which can be fastened to the grinding wheel housing and has at least one opening for guiding a welding electrode to be processed in a defined position relative to the grinding wheel. The plane of the grinding wheel coincides substantially with the parting plane between the grinding wheel housing and the attachment. The attachment may have a plurality of mutually offset, different openings for receiving different types of welding electrodes. However, the attachment can also have a plurality of mutually offset openings whose axes intersect the plane of the grinding wheel at different angles. In the grinding wheel housing, a radial slot extending over the end face of the housing can be formed, through which a welding electrode for cutting can be applied to the circumferential surface of the grinding wheel. In the disclosed apparatus, the grinding wheel is fixed to a grinding wheel receiving, which in turn is connected to the motor shaft of the drive motor. The entire device forms a portable unit. From DE 102 43 210 B3 an arrangement is known in which two parallel grinding wheels of different grain sizes are used. A first grinding wheel circulates in a cavity between the motor attachment and a first housing attachment. The second grinding wheel runs in a second cavity between the first housing attachment and the second housing attachment. The housing attachments are provided with openings for guiding the welding electrodes. The known arrangement allows the use of different grinding wheels with standard dimensions without conversion.

The assembly uses next to a motor with a motor housing further housing parts: a motor flange which is screwed directly to the motor housing and at least one housing part, in which the openings are provided for guiding the electrodes. The openings each extend from the side remote from the motor in the housing part in the direction of the grinding wheel, which rotates between the motor flange and the housing part. Depending on the number of grinding wheels further housing parts are placed. Again, the breakthroughs start on the side facing the engine. In other words, the electrodes are always introduced to the motor in the breakthroughs. The arrangement is comparatively long depending on the number of housing parts and requires a long drive shaft. For attachment of the housing parts several other fastening components, such as screws, nuts, pins, etc. required.

DE 10 2006 052904 A1 discloses an arrangement in which two grinding wheels or abrasion surfaces of different grain size practically circulate in one plane in a common cavity. The abrasion surfaces are facing away from each other in this known arrangement. Between the grinding wheels a third disc of larger diameter is arranged. Electrodes can be cut on this disc. The assembly operates either with a grinding wheel having two abrasive surfaces of different grain size or with a grinding wheel assembly of at least two grinding wheels. The holes in which the electrodes are guided are manufactured with high precision with respect to the angle.

All known arrangements produce unwanted dust from abraded material and abrasive wear. The dust is harmful to your health. It is therefore known that Store dust in a housing and dispose of it at regular intervals. This is tedious and ineffective.

Disclosure of the invention

It is an object of the invention to provide a grinding device for electrodes, which excludes a health hazard caused by particles produced. It is a further object of the invention to avoid the health hazard even in devices already on the market.

According to the invention, the object is achieved by a suction device connected to the device, via which particles generated during the Scheifvorgangs be sucked out of the housing. Then the harmful particles or other gases, etc. are sucked out immediately after their production and can cause no health damage even when disposed of. A separate disposal is eliminated. Preferably, the housing is disposed in a sealed protective sheath having an opening which is positionable over the sheath-side end of the selected aperture. Through the opening, the electrodes can be inserted into the selected breakthrough for grinding. All other openings are surrounded by the protective cover. The particles can not escape through the remaining openings. The suction device can be used on any of the devices mentioned in the prior art. The protective cover not only serves to hold the suction device, but also as splash and eye protection. The protective cover may comprise a transparent hollow cylinder, which is arranged substantially around the region of the housing in which particles are produced and on the plan side of an opening for the connection of the suction device is provided. A cylindrical shape is useful in a cylindrical housing geometry. Then, the opening can be positioned by rotating the sheath about the common axis. In other, approximately cuboid housing geometry, for example, a cuboid housing geometry is conceivable, which is correspondingly repositioned. Also, a protective cover made of flexible material may be useful depending on the application. Preferably, the connection of the suction device is sealingly guided through the opening in the protective cover to a conical receptacle in the housing and pinned there. The housing has a receptacle on the side facing away from the engine. The suction device can be guided for example with a tube, cone or a fixed end of the hose into the receptacle and pinned there or otherwise sealingly attached.

Preferably, the hollow cylinder extends at a distance up to the motor housing and is sealed in the region of the motor housing by means of a sealing ring, in particular made of foam to the outside. Then no particles can escape at the lower end of the protective cover.

In a particularly preferred embodiment of the invention, the suction device comprises a water bath, through which the suction flow is guided, so that the particles are filtered in a water bath. A water bath has the advantage that even the smallest particles get stuck. Carcinogenic particulate matter pollution is thus avoided. The water is a low cost, easily replaceable filter material.

The object is further achieved with a kit for retrofitting a device for machining of welding electrodes of the type mentioned, which is characterized by

(A) a connectable with the device suction, over which particles generated during the Scheifvorgangs be sucked out of the housing, and

(b) a protective cover which is sealable against the housing and has an opening which is positionable over the shell side end of a selected aperture.

Existing devices on the market can be retrofitted in a cost-effective manner. The device itself does not need to be changed or replaced. Preferably, the protective cover of the kit comprises a transparent hollow cylinder which is arranged substantially around the region of the housing in which particles are produced, and on whose plan side an opening for the connection of the suction device is provided. It may also sealants for sealing the Protective cover relative to the housing and / or the motor housing includes his.

Also in the kit, the suction device may comprise a water bath through which the suction flow is performed, so that the particles are filtered in a water bath.

Embodiments of the invention are the subject of the dependent claims. An embodiment is explained below with reference to the accompanying drawings.

Brief description of the drawings

FIG. 1 is an exploded view of a device for grinding. FIG

Electrodes with two grinding wheels without suction device.

Fig. 2 is a cross-section through an apparatus for grinding electrodes with a grinding wheel without a suction device.

3 shows the head of the device from FIG. 1 as an exploded view in FIG

Detail.

4 shows the arrangement of Figures 1-3 in section along a first

Cutting plane.

5 shows the arrangement of Figures 1-3 in section along a second

Cutting plane.

6a-d show sections and an exploded view of a protective cover for the

Arrangement of Figures 1-3 for receiving a suction device.

FIG. 7 illustrates the connection of a suction device to an arrangement from FIGS. 1-3. Description of the embodiment

In the figures, 10 generally indicates a device for grinding tungsten welding electrodes. The apparatus 10 includes a motor having a motor housing 12, a motor flange 14 bolted to the motor housing 12, and a cylindrical housing portion 16 mounted on the motor flange 14. The housing portion 16 is connected to the motor and motor flange in the manner described below. In the area between the motor flange 14 and the housing part 16, a grinding wheel assembly 18 rotates with grinding wheels 20 and 22 of different grain size.

The flange is provided with holes. About these holes, the motor flange 14 is screwed to the motor housing 12 in the manner shown in Fig.l manner with screws 24. The housing part 16 is fixedly connected to the motor flange 14 with a screw 13 and a nut 15. For this purpose, the housing part 16 has a through hole and the motor flange has a receptacle for the nut 15.

At the end remote from the motor 26 of the motor flange 14, a disc-shaped recess is provided. This recess serves to receive the grinding wheel 22. The shaft 30, with which the grinding disc assembly 18 is screwed to the motor, is also the motor shaft.

The shaft 30 has a front part 28. Furthermore, the shaft 30 with front part 28 has a bore 32 with an internal thread. In addition, an off-axis pin 34 is attached to the front part 28. The grinding wheels 20 and 22 of the grinding wheel assembly 18 are provided with a central bore and an associated, off-axis bore. The grinding wheels 20 and 22 are mounted on the shaft 30 and screwed with a screw 36 that the central bore with the axial bore 32 in the shaft 30 is aligned and the pin 34 through the off-axial bore in the motor-side grinding wheel 22 protrudes. The rotation occurs about the axis of the central bores, with the pin 34 engaging the off-axis bore and transmitting the drive force to the grinding disc assembly 18. A centering sleeve 37 is from above through the center holes of the two grinding wheels 20 and 22 plugged. The centering sleeve 37 has at the top, facing away from the motor, a receptacle 39 for the screw head of the screw 36. The centering sleeve 37 ensures that both grinding wheels 20 and 22 rotate about the same axis. The centering sleeve 37 also has a protruding nose 41. The nose engages the off-axis bores 40 of the grinding wheels 20 and 22. In this way, the driving force of the motor is transmitted from the first motor-side grinding wheel 22 via the centering sleeve 37 to the second, upper grinding wheel 20. The centering sleeve 37 is screwed together with the grinding wheels 20 and 22 with the screw 36 on the shaft. This can be seen particularly well in FIG.

In this embodiment, the grinding wheel assembly 18 comprises a coarse-grained grinding wheel 20 and an otherwise equally constructed, fine-grained grinding wheel 22. The grinding wheel 20 has a particularly fine edge 42. This edge 42 serves to cut the electrodes with improved cutting behavior. The edge is formed on the grinding wheel 20 so that it lies with one side in the grinding plane. In this way, one of the grinding surfaces, namely the upper grinding surface in Figures 4 and 5 on the side of the edge 42 is larger than the opposite grinding surface. When the grinding disc assembly 18 is inserted with the shaft 30, the substantially cylindrical housing member 16 and a spacer ring 64 (Figure 5) is coaxially mounted on the motor flange 14.

The housing part 16 is provided with a central bore 54. This can be seen in Figure 4. The central bore 54 is aligned with the bores of the Schleifscheibenanordung 18 and the axis of rotation of the shaft 30. Around the bore 54 around the motor facing plan side 56, a disc-shaped recess 58 is provided. On the side facing away from the motor of the motor side 60 of the housing part 16 a recess 62 is provided These recesses 58 and 62 have approximately the same dimensions as the recess on the plan side 26 in the motor flange 14. The recesses in the plan side 26 and the recess 58 form in composite Arrange together a cavity. The cavity serves to receive the grinding disc arrangement 18. Between the motor flange 14 and the housing part 16 the spacer ring 64 is arranged. The thickness of the spacer ring 64 corresponds to the thickness of a grinding wheel 20 or 22. Accordingly, the difference is compensated by the additional grinding wheel. It can be used regardless of the number of grinding wheels always the same motor flange 14 and and the same housing part 16 with the same recess 26 and 58 respectively. The grinding angle does not change.

The housing 16, the ring 64 and the motor flange 14 also have a longitudinal slot 66 in the radial direction, which extends over the entire thickness of the assembly. The longitudinal slot 66 can be seen in FIG. The slots 66 in motor flange 14, ring 64 and housing 16 are superimposed. The slot 66 thus formed is wide enough that the electrodes can be inserted there. With the grinding wheel assembly 18 rotating, the electrode at the edge 42 of one of the grinding wheels can be shortened by cutting off the spent electrode end or the newly ground electrode side.

The housing 16 and the motor flange 14 have groups 76 and 78 of holes in the form of holes. The bores each extend from the circumference on the shell side of the housing 16 or motor flange 14 to the associated plan sides in the direction of the grinding wheel closest to the housing or motor flange. Each group includes in a known manner a plurality of holes (also referred to as breakthroughs) of different diameters, which is respectively indicated above or below the bore by an engraving 80. This can be seen in FIG. The angle at which an electrode inserted into a bore or a breakthrough strikes the grinding wheel is the same within a group of bores. The bore thus has, for example, a diameter of 4 mm and a grinding angle of 30 degrees. The Anschleifwinkel is indicated by a further engraving 82 above the first engraving for each group. For example, four different angles are possible with a bevel. In this case, electrodes with, for example, up to six different diameters can be used. The electrode is guided so well through the hole that reproducible results are obtained without effort or risk. More grinding angles, more electrode diameters or the use of a grinding surface with different grain sizes are taken into account by the motor flange 14 has just such holes 78 and two grinding wheels are used. For example, an electrode may first be coarsely pre-ground by passing it through a bore in the housing 16. In this case, a rough grain is provided for the grinding wheel 20, the abrasion surface facing upward in the illustration. For fine grinding then a hole in the motor flange 14 is used. The associated grinding wheel 22, the abrasion surface faces down, has a fine grain. Both the holes 76 in the housing part 16, as well as the holes 78 in the motor flange were made with the same machine with identical settings. The holes are therefore identical with minor deviations. The abrasion surface is always in the same plane in the present arrangement. In this way, a particularly low error in the grinding angle is achieved. In the present example, the holes 76 are made so that the specified Anschleifwinkel is achieved when the abrasion surface is in the plane 60 and the holes 78, when the abrasion surface is in the disc thickness lying below the plane 26 level.

The housing 16 further includes a group of bores extending perpendicularly from the top to the bottom of the housing 16. The holes in this group have different diameters, which correspond to the diameters of the other groups. The holes in the group allow vertical grinding of the electrode tips. The entire assembly is screwed onto a hand-held device. The grinding wheel assembly sits directly in front of the ball bearing of the motor shaft 30. This prevents rolling at high speeds.

To prevent the penetration of dust, worn material and abrasive and the like into the engine or the bearing, a baffle plate 84 is provided. The baffle 84 is slipped between the motor-side grinding wheel 22 and the motor flange with a sleeve 86 on the upper end 28 of the motor shaft 30 and rotated with. The motor-side, lower surface of the baffle plate 84 is in the region of the bottom the recess in the plan side 26. Around the sleeve 86 around a felt ring 88 is arranged, which does not rotate. The felt ring 88 avoids further penetration of dust, abraded material and abrasive into the engine and bearing. The pin 34 extends through a bore in the baffle plate 84. In this way, not only the grinding wheel assembly 18, but also the baffle 84 is driven by the shaft 30.

The present arrangement has been explained of a concrete embodiment with two grinding wheels. It is understood that the arrangement can be varied. Thus, for example, it is possible to use only one grinding wheel or another housing part, similar to the housing part 16, set up and provide in the intermediate cavity more grinding wheels. Also, different configurations of the holes for guiding the electrodes are conceivable. The assembly has a protective sleeve of plexiglass, generally designated 90, which is shown separately in FIG. The protective cover 90 comprises a hollow cylinder 92 and two cover parts 94 and 96. Through the protective cover, the motor flange 14 and the housing part 16 with the bores 76 and 78 for the electrodes continue to be clearly visible even with a protective cover. The dimensions of the hollow cylinder is chosen so that it is supported on an annular projection 98 on the outside of the motor flange and extends beyond the end of the housing part 16.

The hollow cylinder 92 has an elongate opening 100. The opening 100 extends just above the area of the underlying bores 76 and 78 in the housing part 16 and in the motor flange 78. By rotating the hollow cylinder 92 about its longitudinal axis, the opening 100 can be positioned over the selected bore. The electrode to be ground can then be easily inserted through the opening in the bore. The hollow cylinder 92 has on the side facing away from the engine, a two-part cover with cover parts 94 and 96. The lying between the outer cover member 96 and the upper edge of the hollow cylinder 92 cover member 94 is provided on the engine-facing bottom with two recesses, which are around two Holes 102 and 104 extend around. The cover part 96 has two corresponding threaded bores 106 and 108. The cover parts 94 and 96 are screwed together with two screws 110 and 112. The screw head of the screws 110 and 112 is completely sunk in the lower side recesses in the cover part 94.

Both cover parts 94 and 96 are fastened with a screw 114 to the housing part 16, as shown in Figure 4. For this purpose, bores 116 and 118 are provided in the cover parts 94 and 96, respectively. The screw 114 engages a nut 120, which is laterally inserted into the housing. The opening and bore provided for this purpose can be used on the one hand to set up further housing parts for further grinding wheels or for the attachment of the cover, as is the case in the present illustration. In the outer cover part 96, two opposing bores 122 and 124 are provided. Through these holes protrude two short screws 126 and 128, which are screwed into a corresponding, underlying threaded hole in the cover part 94. With the screws 126 and 128, a comparatively large-area nut 130 is clamped between the cover parts in each case. The nut 130 presses on the upper edge of the hollow cylinder 92 and holds it in its position. In this way, the hollow cylinder is locked in its angular position. He can not move during the grinding process and the general handling. To adjust the aperture 100 to a different position above another bore 76 or 78, the screws 126 and 128 are loosened somewhat. Then the hollow cylinder 92 is freely rotatable. After positioning the screws 126 and 128 tightened again and the hollow cylinder 92 is locked in place.

If, as in the embodiment described above, two grinding wheels 20 and 22 are used, the hollow cylinder is extended by a grinding wheel thickness, with an intermediate ring 132 of the same diameter. Then, the nuts 130 press on the intermediate ring 132. If only one grinding wheel 120 and no spacer ring 64 are used, the intermediate ring 130 is not inserted. Then press the nuts 130 directly on the upper edge of the hollow cylinder 92. In this way, the same hollow cylinder can be used for all arrangements regardless of the number of grinding wheels.

The cover parts 94 and 96 each have a central opening 134 and 136. The center opening 134 has a slightly larger diameter than the center opening 136. In this way, an edge 138 is formed.

A suction device 140 (FIG. 7) with a pump 142 is connected to the device 10 by means of a hose 144. The hose end is guided through the openings 134 and 136 to the center opening 54. The center opening 54 has an upwardly conically widening wall. The end of the hose is sealingly clamped in the cone thus formed. Now, when the suction device 140 is actuated, arises in the interior of the housing part 16 and the motor flange 14, a negative pressure. The air is sucked in through the openings. In this way, the very different openings 76 and 78 do not need to be sealed in a difficult manner. The sanding dust and all other particles and gases can no longer escape or accumulate.

If the hose end of the suction device 140 has no suitable dimensions, an adapter (not shown) can be used, which fits into the cone. The adapter may be externally designed so that it is held on the edge 138. The hose end can then be secured in the appropriate adapter.

It has been found that from suction devices 140 are particularly well suited with a water filter 146. The particle-containing flow is passed through a water bath. The tungsten and other particles remain in the water. It arises neither in the filtering process, nor in the disposal of umweit- and harmful particulate matter. The tungsten particles contained in the water may be recycled by evaporating the water or by precipitation. From the recovered tungsten, for example, electrodes can be produced again. The disposal and / or recycling of the material takes place without harmful environmental influences.

Claims

claims

Apparatus (10) for machining welding electrodes with a grinding wheel (20; 22) driven by a drive motor via a shaft (30), which rotates in a cavity in a housing (14, 16), wherein in the housing (14, 16) at least one breakthrough (76, 78) is provided for guiding a welding electrode to be processed in a defined position relative to the grinding wheel (20; 22), characterized by a suction device (140) connected to the device, via which particles generated during the Scheifvorgangs from the housing (14, 16) are sucked.

Apparatus according to claim 1, characterized in that the housing (14, 16) in a sealed protective sheath (90) having an opening (100) is arranged, which can be positioned over the sheath side end of the selected aperture (76, 78).

Apparatus according to claim 2, characterized in that the protective sheath (90) comprises a transparent hollow cylinder (92) which is arranged substantially around the region of the housing (14, 16) in which particles are produced and on the plan side of an opening (134, 136) is provided for the connection of the suction device (140).

Apparatus according to claim 3, characterized in that the connection of the suction device (140) sealingly through the opening (134, 136) is guided in the protective sleeve to a conical receptacle in the housing (16) and pinned there.

Apparatus according to claim 3 or 4, characterized in that the

Hollow cylinder (92) spaced apart extends around the motor housing (14, 16) and is sealed in the region of the motor housing by means of a sealing ring, in particular made of foam to the outside. Device according to one of the preceding claims, characterized in that the suction device (140) comprises a water bath (146) through which the suction flow is guided, so that the particles are filtered in a water bath.

Kit for retrofitting a device (10) for machining welding electrodes with a grinding wheel (20; 22) driven by a drive motor via a shaft (30), which rotates in a cavity in a housing (14, 16); 14, 16) is provided at least one opening (76, 78) for guiding a welding electrode to be machined in a defined position relative to the grinding wheel (20, 22), characterized by

(A) a suction device (140) connectable to the device, via which particles generated during the Scheifvorgangs from the housing (14, 16) are sucked, and

(b) a protective sheath (90) sealable against the housing (14, 16) and having an opening (100) positionable over the sheath side end of a selected aperture (76, 78).

Kit according to claim 7, characterized in that the protective cover (90) comprises a transparent hollow cylinder (92) which is arranged substantially around the region of the housing (14, 16) in which particles are produced, and on the plan side thereof Opening (134, 136) for the connection of the suction device (140) is provided.

Kit according to claim 8, characterized in that further comprises sealing means for sealing the protective cover relative to the housing and / or the motor housing.

Kit according to one of claims 7 to 9, characterized in that the

Extraction means (140) comprises a water bath (146) through which the suction flow is guided, so that the particles are filtered in a water bath.