Support element for a housing underside

Abstract

Hand tool (1; 101), in particular for cutting and / or grinding materials for the removal of windows and doors or the like installed in masonry (MW), comprising: - a drive motor (2), - a milling disc (3) connected to the drive motor (2) via a shaft (8), - a housing (4) enclosing the milling disc (3), comprising an upper housing surface (4a) facing the drive motor (2) and an lower housing surface (4b) facing away from the drive motor (2), - at least one guide slide (5; 6) connected to the housing (4), - wherein the drive motor (2) and thus the milling disc (3) is displaceable via the guide slide (5; 6) in such a way as to allow the milling disc (3) to be displaced on the housing (4) in the direction of at least one exit opening (10; 11) for the milling disc (3) at least partially exiting the housing (4) to perform a cutting or grinding operation.milling work protrudes, characterized in that at least one support element (19; 119) is arranged between the milling disc (3) and an inner surface (20) of the underside of the housing (4b) facing away from the drive motor (2), wherein the support element (19; 119) is designed as a two-part support element (219) comprising a body (K219) and a sliding and support body (GS219), wherein the sliding and support body (GS219) is received in a pocket (T219) of the body (K219) and protrudes beyond it and is designed as a ball (K).

Description

The invention relates to a hand tool, in particular for cutting and / or grinding materials for the removal of windows and doors or the like installed in masonry. Hand tools of the type mentioned above are known from the prior art. These generally comprise a drive motor and a milling disc connected to the drive motor, the milling disc being arranged in a housing that encloses it. Different embodiments of such hand tools allow the milling disc to be moved out of the housing by pressing the housing against a surface to be machined, thus enabling a cut or milling operation to be carried out. This movement is usually made possible by at least one guide slide being arranged on the housing such that the housing can be moved relative to the milling disc and thus to the drive shaft connecting it to the drive motor. Advantageous embodiments of such hand tools exist which, in addition to the milling disc exiting on a first side of the housing, also allow the milling disc to exit on another side of the housing and / or on a housing diagonal or corner. Such hand tools are particularly advantageous when corners of window reveals or the like need to be cut out, as this allows a cut right into the corner. Document US 2006 / 0156877A1 discloses a saw assembly comprising: an electric motor subassembly, wherein the electric motor subassembly has a motor capable of generating rotary motion about a first axis of rotation, and a spindle rotatably driven by the electric motor to rotate about a second axis of rotation perpendicular to the first axis of rotation; a blade mounted on the spindle; and a retractable, fully enclosing blade guard guide subassembly, wherein the blade guard guide subassembly comprises an upper main guard guide slidably mounted on the electric motor subassembly, and a lower guard guide plate attached to the upper main guard guide subassembly. Document US 4,909,680 A discloses a device for milling grooves or rabbet joints, comprising a stop angle with a base plate and an end plate, and guide elements for a slide that is provided on the stop angle parallel to the base plate, a slide that is slidably mounted on the guide elements, and return springs for biasing the slide against displacement toward the end plate, wherein the slide has means for supporting a handheld angle grinder as a drive motor and for supporting a milling disc that can be driven by the angle grinder, a slotted through-opening provided in the end plate for receiving a milling disc supported by the slide, and wherein the means for supporting the angle grinder comprises two multi-part mounting brackets between which the angle grinder is mounted by means of mounting screws,which engages in threaded holes for guide handles of the angle grinder, can be clamped, and comprises a coupling shaft mounted in the slide, wherein the coupling shaft has a threaded bore in an upper end for receiving a threaded outlet fitting of an angle grinder, and wherein the means for carrying a milling disc comprises means for attaching a milling disc to the lower end of the coupling shaft. A disadvantage of the handheld tools described at the beginning is that the housing, especially the housing wall facing away from the guide carriage and thus the motor, which is usually made of sheet metal, is constantly subjected to the contact force generated when working with the tool. Depending on the surface finish and application, this deformation can occur during the cutting process, causing it to deform in the direction of the milling disc. While such deformation is not critical to a certain extent, practical experience shows that the underside of the housing (base plate) is often bent, or damage occurs due to contact with the milling disc or fasteners during cutting. The invention is therefore based on the objective of improving a hand tool described above in such a way that problems caused by damage to the underside of the housing or base plate are avoided. This objective is achieved, starting from the preamble of claim 1, by the characterizing features of claim 1. Advantageous further training opportunities and appropriate design options are specified in the dependent requirements. Specifically, the invention relates to a hand-held tool, in particular for cutting and / or grinding materials for the removal of windows and doors or the like installed in masonry, comprising: - a drive motor, - a milling disc connected to the drive motor via a shaft, - a housing enclosing the milling disc, comprising an upper housing surface facing the drive motor and a lower housing surface facing away from the drive motor, - at least one guide slide connected to the housing, - wherein the drive motor and thus the milling disc can be displaced via the guide slide in such a way as to be directed towards at least one exit opening for the milling disc on the housing, such that the milling disc protrudes at least partially from the housing to carry out a cutting or milling operation. The invention is characterized in that at least one support element is arranged between the milling disc and an inner surface of the underside of the housing facing away from the drive motor. The arrangement of a support element between the milling disc and the underside of the housing, which is also referred to as the base plate, makes it possible to counteract deformations of the housing and especially the base plate that occur when working with the hand tool, and to additionally support the base plate, especially at one point, so that damage, in particular permanent deformation of the base plate or a collision between the running milling disc and the base plate or fastening elements, is avoided. In a practical further development, the support element is designed to extend axially along the shaft. The rotational speed of the milling disc is lowest axially along the shaft. This results in the lowest centrifugal force and circumferential speed acting on the support element, and thus low friction coefficients, so that corresponding loads can be largely disregarded. In a particularly advantageous embodiment, the support element is designed to move along with the milling disc. This arrangement offers the advantage that, when the milling disc exits the housing, the support element is positioned close to the housing opening, eliminating the need for a support element protruding through the housing edge. This optimizes the support effect, further improving the prevention of damage to the housing, especially the base plate. Furthermore, it is advantageous that the support element comprises a surface facing the inner surface of the housing's underside, away from the drive motor, which slides against the inner surface during operation of the hand tool. This ensures that the base plate always receives a certain degree of support, and this support counteracts damage when the milling disc exits the housing, i.e., during operation. Furthermore, the support element is designed to have a minimal gap, in particular < 1 mm, preferably < 0.5 mm, between its surface and the inner surface of the housing side. While this does result in a slight deformation of the housing before the support element becomes active, this deformation is negligible and does not cause any permanent damage. Moreover, no continuous friction occurs during operation of the hand tool, as the support element only becomes active once a certain level of initial deformation has been reached. It is further advantageous for the support element to be designed with a base, wherein the base is connected to the shaft and / or a clamping element for the milling disc and / or the milling disc itself, and in particular engages with these, wherein the clamping element is designed in particular as a clamping nut or clamping screw, and wherein the support element is arranged in a rotationally fixed manner relative to the milling disc during operation, i.e., it rotates with the milling disc, the shaft, or the clamping element during operation. Typically, such milling discs are fastened to the drive shaft by means of threaded nuts or screws. Other fastening methods known from the prior art are also possible. These fastening methods have in common that a corresponding connecting engagement occurs centrally, in the longitudinal axis region of the drive shaft, between the clamping element and the shaft in which the milling disc is clamped.Within this fastening system, the support element according to the invention can be integrated or attached to it. Furthermore, it is advantageous for the support element to have a mushroom, spherical, ring, or conical shape. Such support elements are easy to manufacture industrially and offer maximum flexibility for installation and / or retrofitting, ensuring low friction between the support element and the base plate when the rotating support element is pressed against the base plate or moved relative to it, utilizing the degrees of freedom provided by the guide carriage. Furthermore, it is advantageous for the support element to also be arranged on an inner surface of the housing, particularly as a support strip along the milling disc's path of movement, especially around its center point. This arrangement along the milling disc's path of movement—that is, along the axial movement towards the housing exit in the case of a purely linear milling disc, or along the corresponding paths of movement in the case of a diagonally guided milling disc, or in the case of an L-shaped milling disc—makes it possible to dispense with a support element in the axial area, thus providing adequate support on the housing itself. Such support can be easily retrofitted to existing hand tools without requiring the support element's geometry to be adapted to the specific milling disc mounting. Furthermore, it is advantageous to have a hand-held tool according to the preamble of claim 1, in which the support element is designed such that, when the milling disc exits the housing in the front and / or side direction, the axis and the base plate of the housing are supported against each other during the removal of windows and doors or the like installed in masonry. The arrangement of a support element between the milling disc and the underside of the housing, which is also referred to as the base plate, makes it possible to counteract deformations of the housing and, in particular, the base plate that occur when working with the hand-held tool, and to additionally support the base plate, especially at a point, so that damage, in particular permanent deformation of the base plate or a collision between the rotating milling disc and the base plate, is avoided. The hand tool is designed with either a one-piece or a two-piece support element comprising a body and a sliding / supporting element. The sliding / supporting element is housed in a pocket within the body and protrudes beyond it, particularly in the form of a sphere. A one-piece support element is cost-effective and easy to manufacture. A two-piece support element, on the other hand, allows for optimal design with regard to ease of assembly (simply pressing it in) and wear and sliding properties, thanks to the use of different materials. Further details of the invention are described in the drawing with reference to schematically illustrated embodiments. Figure 1 shows a horizontal section through a first embodiment of a hand tool according to the invention, corresponding to section line II indicated in Figure 2; Figure 2 shows a cross-section through the hand tool shown in Figure 1; Figures 3 and 4 show longitudinal sections through the hand tool shown in Figure 1, with the milling disc in Figure 3 in a rest position and the milling disc in Figure 4 in a working position; Figure 5 shows a longitudinal section through a second embodiment of a hand tool according to the invention; Figure 6 shows a sectional view of the housing of the hand tool shown in Figure 5, corresponding to section line IV-IV shown in Figure 5; and Figures 7a and 7b show a cut and an uncut side view of a further support element. Figure 1 shows a horizontal section through a first embodiment of a hand-held tool 1 according to the invention, corresponding to section line II indicated in Figure 2. Components of the hand-held tool 1 located above section line II are indicated by dashed lines. The hand-held tool 1, which is designed as a so-called window milling cutter FF, comprises a drive motor 2, a milling disc 3, a housing 4 enclosing the milling disc 3, a first guide slide 5, a second guide slide 6, and a handle body 7 in which the drive motor 2 is housed. The drive motor 2 comprises a shaft 8 via which the drive motor 2 is non-rotatably connected to the milling disc 5. The housing 4 comprises an upper housing surface 4a facing the drive motor 2 and a lower housing surface 4b facing away from the drive motor 2 (see also Figure 2), the lower housing surface 4b also being referred to as the base plate.The shaft 8 includes a collar 9, which guides the drive motor 2 and the surrounding handle 7 into the intersecting guide slides 5 and 6. The housing 4 includes a first outlet opening 10 and a second outlet opening 11, through which the milling disc 3 can exit the housing 4. Figure 1 shows a home position G1, a first working position A1, and a second working position A2 of the milling disc 3. Naturally, the milling disc 3, together with the shaft 8, the drive motor 2, and the handle 7, is moved and transported or shifted within the guide slides 5 and 6. In the plane of Figure 1, this movement proceeds from the home position G1, in which the milling disc 3 is shown with thin dashed lines, initially in the x-direction to the working position A1. In the working position A1, the milling disc 3 is indicated with thick dashed lines outside the housing 4.From the working position A1, the guide slide 6, into which the guide slide 5 transitions, allows the milling disc 3 to be moved in the y-direction to the second working position A2, in which the milling disc 3 is also indicated by thick dashed lines outside the housing 4. The shaft 8 is shown in the three positions G1, A1, and A2, just like the milling disc 3. Figure 2 shows a cross-section through the hand tool 1 shown in Figure 1, corresponding to section line II-II indicated in Figure 1. This cross-section shows how a sliding unit 12, comprising the drive motor 2 with its shaft 8, the handle body 7, and the milling disc 3, is displaceable relative to the housing 4 and in the guide slide 5 connected to the housing 4. The sliding unit 12 is guided in the guide slide 5 by the collar 9 formed on the shaft 8. Of course, the guidance of the sliding unit 12 can also be implemented differently in an equivalent manner. The hand tool 1 further includes a clamping element 13, by which the milling disc 3 is non-rotatably connected to the shaft 8.The clamping element 13 is designed as a clamping screw 14, which is screwed through a bore 15 in the milling disc 3 into an internal thread 16 provided in the shaft 8 such that the milling disc 3 is pressed against the shaft 8 by a head 17 of the clamping screw 14. For actuation of the clamping screw 14, its head 17 has a recess 18 adapted to a socket wrench (not shown). The hand tool 1 further comprises a support element 19, which is arranged between the milling disc 3 and an inner surface 20 of the lower housing 4b of the housing 4. The support element 19 comprises a head 19a and a neck 19b, wherein the head 19a is designed as a spherical cap 21 and has a surface F19, and wherein the neck 19b connected to the head 19a is designed as a pin-shaped foot 22.The foot part 22 is designed with regard to its dimensions and elasticity in such a way that it can be inserted into the recess 18 of the clamping screw 14 and is held captive in it. Figure 3 shows a further section through the hand tool 1, the section being formed according to section line III-III indicated in Figure 1, and the shaft 8, the milling disc 3, and the support element 19 being shown in a simplified manner, omitting the clamping element 13. In Figure 3, the displacement unit 12 is in its home position G1 and is not yet subjected to the contact forces exerted by a tradesperson via the handle 7 during use of the hand tool 1. In the unloaded rest position shown, the head 19a of the support element 19, with its surface F19, has a distance D1 to the inner surface 20 of the housing underside 4b or the base plate. In Fig. 4, the hand tool 1 is shown in the same view as in Fig. 3. However, it is no longer in its home position G1, but in the first working position A1. This means that the sliding unit 12 has been pushed out of the housing 4 through the exit opening 10 in the direction of arrow x, with the milling disc 3 cutting into a piece of masonry MW in the area of ​​a window reveal FL as it is being pushed out. The craftsman handling the hand tool 1 exerts a pushing force SK and a compressive force DK on the sliding unit 12 via the handle 7. As a result of the forces SK and DK, which act as a resultant force RK, slight deformations of one or more components of the hand tool 1 occur, and / or one or more components of the hand tool 1 are displaced relative to each other due to existing play.This complex process, which also depends significantly on the acting forces and a substrate UG on which the base body 4 with its housing underside 4b or its base plate is placed, is schematically depicted in Fig. 4 such that the displacement unit 12 is moved relative to the housing 4 in the direction of arrow z by utilizing a clearance in the guide slide 5, 6 by the acting forces SK and DK. Here, the support element 19 with its head 19a prevents the milling disc 3 from approaching the inner surface 20 of the housing underside 4b too closely, with the support element 19, with the surface F19 of its head 19a, supporting the housing underside 4b or the base plate on its inner surface 20, so that it is not deformed too much and, in particular, not permanently.In contact with the inner surface 20 of the underside of the housing 4b, the support element 19, with its surface F19, slides and rotates on the inner surface 20 about a rotational axis R8 of the shaft 8 or the milling disc 3, thus minimizing wear due to friction. The support element 19 also exerts its stabilizing effect under appropriate load on the hand tool 1, during the movement of the milling disc 3 from the home position G1 to the first working position A1, and during the movement of the milling disc 3 from the first working position A1 to the second working position A2, and in the second working position A2, as well as when the milling disc 3 is retracted to the home position G1. Figure 5 shows, analogous to Figure 3, a longitudinal section through a second embodiment of a hand tool 101 according to the invention. The hand tool 101 essentially has the same components and functions as the hand tool described in Figures 1, 2, 3 to 4. In this respect, explicit reference is made to the descriptions of these figures, and Figure 5 is labelled with the reference numerals mentioned therein. However, unlike the embodiment shown in Figures 1, 2, 3 to 4, the embodiment shown in Figures 5 and 6 does not include a support element with a head and neck connected to the sliding unit 12, but rather a support element 119 connected to the inner surface 20 of the lower housing 4b. Here, the support element 119 is designed as a support stiffener 119a, which extends along an L-shaped movement path BWB (see Fig.6) the axis of rotation R8 of the shaft 8 extends, along which it is moved from the basic position G1 via the first working position A1 to the second working position A2. As shown in Fig. 5, the grinding wheel 3, with a surface F3 facing the inner surface 20 of the housing underside 4b, has a distance D2 to the support element 119 in the area of ​​the shaft 8 in an unloaded situation, which may be reduced under appropriate load or under appropriate substrate conditions beneath the housing underside 4b to such an extent that the rotating milling wheel 3 slides with its surface F3 in contact with the support element 119 and the housing underside 4b can safely rest against the milling wheel 3 with its inner surface 20. Figure 6 shows a section through the housing 4 corresponding to section line VI-VI indicated in Figure 5, without showing the milling disc. In the top view of the inner surface 20 of the housing underside 4b, which is shown in the section view, the L-shaped path of the support element 119 along the dashed path of movement BWB is visible. The positions of the milling disc, with its area located under the shaft, in the home position G1 and in the working positions A1 and A2 are indicated by arrows. Figures 7a and 7b show a further support element 219 in side view. The support element 219 shown in a cutaway side view in Figure 7a, like the support element shown in Figure 2, is designed to be pressed into a clamping element 213, which is only indicated in Figure 7a. The support element 219 is designed in two parts and comprises a body K219 and a sliding and support body GS219. The sliding and support body GS219 is designed as a ball K, which is received in a pocket T219 formed in the body K219. In the illustrated embodiment, the sliding and support body GS219 is glued into the pocket T219 and, when a hand tool 201 (incompletely shown in Fig. 7a) is subjected to a corresponding load, a spherical section KA projecting beyond the body 219 in the z-direction comes into contact with an inner surface 220 of a base plate 204b of the hand tool 201.According to one embodiment not shown, the ball is rotatably mounted in the pocket, the pocket encompassing the ball in such a way that it is captive and cannot be lost within the pocket. Fig. 7b shows the support element 219 depicted in Fig. 7a in an uncut side view. The body K219 consists of a cylindrical section K219a and a cap section K219b that projects beyond the cylindrical section K219a in a cap-like manner. The ball K projects beyond the cap section K219b. It is planned to manufacture the one-piece support element 19 or 119, or the body K219 of the two-piece support element 219, from a wear-resistant and low-friction plastic. A suitable plastic is the S-green plastic distributed by Murtfelder. Reference symbol list: 1 Hand tool 2 Drive motor 3 Milling disc 4 Housing 4a Housing top 4b Housing bottom, base plate 5 First guide slide 6 Second guide slide 7 Handle body 8 Shaft 9 Collar of 8 10 First outlet of 4 11 Second outlet of 4 12 Sliding unit 13 Clamping element 14 Clamping screw 15 Bore in 3 16 Internal thread in 8 17 Head of 14 18 Recess in 17 19 Support element 19a Head of 19 19b Neck of 19 20 Inner surface of 4b 21 Ball cap 22 Base 101 Hand tool 119 Support element of 101 119a Support stiffener 201 Hand tool 201 204b Base plate 204b 213 Clamping element 213 219 Support element 219 220 Interior surface 220 A1 First working position of 12 or 3 A2 Second working position of 12 or 3 BWB L-shaped movement path DK Compressive force D1 Distance between 20 and 19a D2 Distance between 119 and 3 FF Window milling cutter FL Window reveal F3 Surface of 3 F19 Surface of 19 G1 Basic position of 12 or3 GS219 Sliding and support body of 219 K Sphere K KA Spherical section of K K219 Body of 219 K219a Cylindrical section of K219 K219b Cap section of K219 MW Masonry RK Resultant force R8 Axis of rotation of 8 SK Shear force T219 Pocket in K219 UG Substrate x, y, z Arrow direction.

Claims

Hand tool (1; 101), in particular for cutting and / or grinding materials for the removal of windows and doors or the like installed in masonry (MW), comprising: - a drive motor (2), - a milling disc (3) connected to the drive motor (2) via a shaft (8), - a housing (4) enclosing the milling disc (3), comprising an upper housing surface (4a) facing the drive motor (2) and an lower housing surface (4b) facing away from the drive motor (2), - at least one guide slide (5; 6) connected to the housing (4), - wherein the drive motor (2) and thus the milling disc (3) is displaceable via the guide slide (5; 6) in such a way as to allow the milling disc (3) to be displaced on the housing (4) in the direction of at least one exit opening (10; 11) for the milling disc (3) at least partially exiting the housing (4) to perform a cutting or grinding operation.milling work protrudes, characterized in that at least one support element (19; 119) is arranged between the milling disc (3) and an inner surface (20) of the underside of the housing (4b) facing away from the drive motor (2), wherein the support element (19; 119) is designed as a two-part support element (219) comprising a body (K219) and a sliding and support body (GS219), wherein the sliding and support body (GS219) is received in a pocket (T219) of the body (K219) and protrudes beyond it and is designed as a ball (K). Manual work tool (1; 101) according to claim 1 , characterized in that the support element (19; 119) is formed axially in extension of the shaft (8). Hand tool (1; 101) according to claim 1 or 2, characterized in that the support element (19) can be moved together with the milling disc (3) when it is moved. Hand tool (1; 101) according to one of the preceding claims, characterized in that the support element (19) comprises a surface (F19) facing the inner surface (20) of the housing underside (4b), which, in operation of the hand tool (1; 101), in particular at least temporarily slides on the inner surface (20). Hand tool (1; 101) according to one of claims 1 to 3, characterized in that the support element (19) comprises a surface (F19) facing the inner surface (20) of the housing underside (4b), which in operation of the hand tool (1; 101) has a distance (D1) to the inner surface (20), wherein the distance (D1) is in particular less than 1 mm, preferably less than 0.5 mm and the surface (F19) slides on the inner surface (20) in particular in the event of a deformation of the housing underside (4b). Hand tool (1; 101) according to one of the preceding claims, characterized in that the support element (19) is connected with a foot part (19b) to the shaft (8) and / or to a clamping element (13) for the milling disc (3) and / or the milling disc (3), wherein the clamping element (13) is in particular designed as a clamping nut or as a clamping screw (14), wherein the support element (19) is in particular arranged in a rotationally fixed manner relative to the milling disc (3) during operation of the milling disc (3). Hand tool (1; 101) according to one of the preceding claims, characterized in that the support element (19) has a mushroom shape or ball cap shape or ring shape or cone shape. Hand tool (1; 101) according to one of the preceding claims 1, 2 or 7, characterized in that the support element (119) is arranged on the inner surface (20), in particular as a support strip (119a) along a movement path (BWB) of the milling disc (3).

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