Hand-held machine tool with outer housing

Abstract

A handheld oscillation machine tool has support devices for maintaining a spacing between internal parts and an outer housing. The support devices are arranged in pairs of first and second support devices. One support device in each pair has a concave circular surface, and the other has an opposed convex circular surface. Elastically deformable damping elements are arranged between the pairs of support devices. The damping elements are deformed from original flat conditions under forces applied by the support devices, and have concave and convex circular surface adjoining the opposed concave and convex circular surfaces at the support devices.

Claims

1. A handheld oscillation machine tool comprising: an outer housing which extends along its longitudinal axis and has a gripping region configured for the tool to be gripped and guided by a user's hand; an electric drive unit which is accommodated in the outer housing and which rotationally drives a driveshaft of the machine tool, wherein the driveshaft has an axis of rotation parallel to the longitudinal axis of the outer housing; and a tool arrangement which is coupled to the electric drive unit and which is arranged at an end region of the outer housing; wherein the outer housing has a defined inner contour; the electric drive unit and the tool arrangement have a defined outer contour; the outer contour and the inner contour are at a predetermined minimum spacing from one another; in order to observe the minimum spacing, support devices with elastically deformable damping elements are provided, including first support devices provided on the outer contour and second support devices provided on the inner contour; the support devices are arranged in pairs of first and second support devices, with one support device in each pair having a concave circular surface centered on an axis, and the other having a convex circular surface that is centered on the axis and axially opposed to the concave surface; the concave and convex surface in each pair has a circumferential periphery centered on the respective axis, and further has a rotationally symmetrical spherical contour with a radius reaching from the respective axis to the circumferential periphery; the damping elements are arranged between the pairs of support devices; and the damping elements are deformed from original flat conditions under forces applied by the support devices, and have concave and convex circular surfaces with rotationally symmetrical spherical contours coaxially adjoining the rotationally symmetrical spherical contours of the opposed concave and convex circular surfaces at the support devices.

2. A handheld oscillation machine tool according to claim 1 wherein the first and second support devices are configured such that supporting forces between the first and second support devices are transmitted predominantly by frictional connection.

3. A handheld machine tool according to claim 1 wherein each damping element is held between the respective pair of support devices under tension that is unequal for different spatial directions.

4. A handheld oscillation machine tool according to claim 2 or 3 wherein a cellular polyurethane elastomer serves as material for the damping elements, the material having a density of between 0.35 and 0.65 kg/dm3.

5. A handheld oscillation machine tool according to claim 1 wherein the pairs of support devices include a pair in which the respective axis intersects the longitudinal axis of the outer housing.

6. A handheld oscillation machine tool according to claim 1 wherein the pairs of support devices include a pair in which the respective axis runs skew with respect to the axis of rotation of the electric drive unit.

7. A handheld oscillation machine tool according to one of claim 5 or 6, wherein the pairs of support devices include a pair in which the common axis runs within a plane orthogonal to the axis of rotation of the electric drive unit.

8. A handheld oscillation machine tool according to claim 1 wherein at least one first support device is arranged at an end of the electric drive unit that is opposed to the tool arrangement.

9. A handheld oscillation machine tool according to claim 1 wherein at least one second support device is arranged at the outer housing in front of the gripping region with respect to the direction of the longitudinal axis.

10. A handheld oscillation machine tool according to claim 1 wherein at least one second support device is arranged at the outer housing behind the gripping region with respect to the direction of the longitudinal axis.

11. A handheld oscillation machine tool according to claim 1 wherein the outer housing comprises at least two shell components.

12. A handheld oscillation machine tool according to claim 11 wherein parting lines of at least two shell components of the outer housing at least partially run in a direction orthogonal to at least one axis of a main effective direction of at least one second support device.

13. A handheld oscillation machine tool according to claim 12 wherein at least two shell components of the outer housing are screwed to one another at a region at which at least one assembly of first and second support device is arranged, wherein the connection is effective in the direction of the axis of the main effective direction.

14. The handheld machine tool according to claim 13, wherein the least two shell components of the outer housing are screwed to one another.

15. The handheld machine tool according to claim 4, wherein the material has a density of 0.4 kg/dm.sup.3.

Description

(1) Further advantages, features and applications of the present invention result from the description in connection with the figures below.

(2) It is depicted in:

(3) FIG. 1: an exemplary handheld machine tool according to the present invention;

(4) FIG. 2: the exemplary handheld machine tool from figure without the front outer housing half shell;

(5) FIG. 3: a three-dimensional representation of a first support device;

(6) FIG. 4: a horizontal section through the tool machine, according to the sectional view IV-IV depicted in FIG. 2;

(7) FIG. 5: a vertical section through an exemplary machine tool, according to the sectional view V-V depicted in FIG. 4; and

(8) FIG. 6: an enlarged view of a section through an assembly of first and second support device, according to the sectional view depicted in section VI of FIG. 5.

(9) FIG. 1 depicts an exemplary handheld machine tool According to the present invention, which is carried out as an oscillation machine tool in the exemplary embodiment. The outer housing 12 has a defined inner contour and composes of tool housing halves 21 and 22. Furthermore, the outer housing 12 as a gripping region 13 which is grasped by the user guiding the machine tool. The outer housing 12 surrounds a driving device driving the machine tool as well as an area of the tool arrangement 15 which additionally protrudes from the front of the outer housing 12. The tool arrangement 15 has a driveshaft 16 oscillation driven around the drive axis 17, wherein the drive axis 17 is arranged with an offset of 90C. downwards with respect to the axis of rotation of the electric drive unit, which coincides with the longitudinal axis of the machine tool in this exemplary embodiment. At the end of driveshaft 16, the tool holder 18 is arranged for accommodation of an eligible processing tool.

(10) FIG. 2 depicts the exemplary handheld machine tool 10 from FIG. 1, wherein the front half shell of the outer housing 12 is not depicted. The drive elements of machine tool 10, particularly the electric drive unit 14 as well as the tool arrangement 15 connected to the electric drive unit 14 by means of screw joints 25, forming a largely rigid unit can be recognized from this view. The axis of rotation 11 of the electric drive unit 14 coincides with it depicted sectional view in its front section.

(11) The electric drive unit 14 and the tool arrangement 15, as far as these are arranged in the area of outer housing 12, have a defined outer contour 19. It is also recognizable from this view, that the boundary of the back half shell 22, which forms the parting line of the outer housing 12 and thereby also part of inner contour 20 of outer housing 12, is arranged at a distance a from the drive elements of machine tool 10. The additional devices of the machine tool as the control device, the power supply or the user interface elements, which are predominantly arranged at the rear area of the housing, are mechanically decoupled with respect to electric drive unit 14 in order to avoid the transmission of forces to outer housing 12. Housing connection positions 27a to 27e arranged at half shell 22, at which the two half shells 21 and 22 are connected to one another by means of screw joints, are also well recognizable.

(12) At the tool arrangement 15, a first support device 31 is arranged at the area that is received within outer housing 12. An additional first support device 32 is arranged in the rear area of electric drive unit 14. At the same position, first support devices 31 and 32 are also arranged at the hidden, opposite side of tool arrangement 15 and electric drive unit 14. Thus, two first support devices 31 respectively are arranged in front of gripping region 13 at the position of the axis of rotation of the electric drive unit 14, wherein the two first support devices 31 surf for transmission of support forces from tool arrangement 15 to outer housing 12. Behind gripping region 13, thus, two first support devices 32 are arranged at the side of electric drive unit 14 opposing tool arrangement 15 at a distance to the axis of rotation 11. So, behind gripping region 13, two first support devices 32 are arranged respectively at a distance to axis of rotation 11 of electric drive unit 14, wherein the two first support devices serve for transmission of support forces from the electric drive unit 14 to outer housing 12. By being arranged orthogonal to axis of rotation 11 and its offset arrangement with respect to the axis of rotation 11, the two first support devices 32 are adapted for supporting towards being effective around axis of rotation 11 with respect to outer housing 12.

(13) FIG. 3 depicts a three-dimensional view of a first support device 31 at tool arrangement 15, wherein the geometry of first support device 31 is essentially equal to the geometry of the first support device 32 arranged at the electric drive unit 14. First support device 31 is formed in the form of a rotationally symmetric deepening strengthened to the outside, which has a hollow calotte form, i.e. the form of a hollow sphere section. By this form, support device 31 is adapted for transmitting forces within a wide variety of effective directions (compared FIG. 6). In FIG. 3, the rotational axis of the geometry of support device 31 is marked, which essentially corresponds to main effective direction 40 of the forces supportable by support device 31.

(14) FIG. 4 depicts a horizontal sectional view through the machine tool running the section depicted in FIG. 2. The section plane is thereby arranged such that it runs through the first support devices 31 and 32 as well as through the axis of rotation 11 of electric drive unit 14 at the front region. At both housing halves 21 and 22, second support devices 36 and 37 are arranged, which cooperate with the first support devices 31 and 32 in order to keep the outer contour and the inner contour at a spacing a from one another, which corresponds to the minimum spacing. In the exemplary embodiment of the machine tool depicted in FIG. 4, the first support devices 31 and 32 and the second support devices 36 and 37 are formed for a corporation with a power transmission element 39 arranged in between, which is charged with an initial tension during assembly of the two housing halves 21 and 22, As can be seen from FIG. 2, connection positions 27a to 27d are positioned at the regions of assemblies of first and second support devices 31, 32 and 36, 37 in order to achieve a charge of an adequate initial tension when using a power transmission element 39. It is well recognizable from FIG. 4, that the main effective direction 40 of both pairs of assemblies of first and second support devices 31, 32 and 36, 37 are arranged within a plane orthogonal to the longitudinal axis of the machine tool and thereby also to the axis of rotation 11 of the electric drive unit 14.

(15) FIG. 5 shows a vertical section orthogonal to the axis of rotation of the electric drive unit 14, wherein the section follows cutting line V-V pictured in FIG. 4. The two housing halves 21 and 22 of the outer housing 12 are only cover thereby in a verticality middle area of the sectional plane. Also in this figure, the spacing a between outer contour 19 at machine tool 15 and inner contour 20 of outer housing 12 can be well recognized. Main effective direction 40 of both assemblies of first and second support devices 31 and 36 runs through the axis of rotation of the electric drive unit 14. The composition and way of effect of the assemblies of first and second support device 31 and 36 is described in more detail in connection with FIG. 6 showing an enlarged view of detail VI.

(16) FIG. 6 shows an enlarged view of a section through an assembly of first and second support device 31 and 36 having a power transmission element 39 arranged in between. As has already been described, first support device 31 formed in the form of the rotationally symmetric deepening having the form of a hollow calotte in its end region. Second support device 36 is formed in the form of a rotationally symmetric pin, formed in the form of a calotte accordingly. Thereby, diameters D1 and D2 of deepening and pin as well as radiuses R1 and R2 of the sections of the deepening and the pin engaging therein hollow calotte-farmed and calotte-formed; are adapted to each other in connection with the measures and material properties of the power transmission element 39 arranged in between such that power transmission element 39 in an assembled condition, i.e. for half shell halves 21, 22 of outer housing 12 fixedly connected to each other in possibly every direction in which the support of forces F shall take place, has the initial tension desired respectively. Thus, it can be achieved that forcesat least up to a certain dimensionare transmitted by frictional connection in power transmission element 39 without the respective first and second support devices block, i.e. without a positive connection between support devices 31 and 36 being formed. The field of effective directions of forces F, which can be supported by the assembly of first and second support device 31 and 36 having a power transmission element 39 arranged in between being displayed in FIG. 6, is depicted by means of arrows F in this view. Adequate sizes of diameter D1 and of radius R1 of first support device 31 are D1=15 mm and R1=11 mm, which cooperates with the second support device 36 with a diameter D2=9 mm and a radius R2=8 mm when using a power transmission element 39 having a thickness of 5 mm.

(17) This exemplary embodiment depicted in FIGS. 4 to 6 is used in order to keep the predetermined minimum spacing a between outer contour 19 of electric drive unit 14 and tool arrangement 15 and inner contour 20 of outer housing 12, first and second support devices 31, 32, 36, 37 between which a power transmission element 39 is arranged. In the same way, the first support devices 31, 32 of FIGS. 1 to 3 can cooperate with accordingly formed second support devices 36 and 37 without having a power transmission element 39 arranged between the support devices. For these exemplary embodiments, support forces such as structure borne sound, heat and vibration are transmitted from the drive elements of the machine tool to the outer housing 12 in the same way as in the case of overcoming the inner frictional forces of the deployed power transmission element 39, i.e, when the first and second support devices 31, 32, 36, 37 are blocking. By means of a hand-held machine tool 10 designed according to the invention, support forces are supported via the first and second support devices 31, 32, 36, 37 opposite outer housing 12, wherein outer housing 12 is decoupled particularly with respect to a structure borne sound, heat and vibration of these devices because of the minimum spacing a of electric drive unit 14 and tool arrangement 15.