Hand-held work tool with decoupled drawbar carrier

Abstract

A hand-held power tool has a lower mass and an upper mass. The lower mass has a tool and a working device for causing the tool to effect a work movement. The upper mass is movable relative to the lower mass and has a drive motor for the working device. A first vibration decoupling device is arranged between the lower mass and the upper mass for decoupling the upper mass from the lower mass in terms of vibration. A guide drawbar guides is provided for guiding the work tool by an operator. An electrical energy storage provides electrical energy for starting the drive motor. A drawbar carrier is carried by the upper mass and is connected to the upper mass via a second vibration decoupling device. The guide drawbar is attached to the drawbar carrier, and the energy storage is carried by the drawbar carrier.

Claims

1. A hand-held work tool, comprising: a lower mass which has a tool and a working device for causing a working movement of the tool; an upper mass which is movable relative to the lower mass and which has a drive component for the working device; a first vibration decoupling device, arranged between the lower mass and the upper mass, for decoupling the upper mass from the lower mass in terms of vibration; a guide drawbar for guiding the work tool by an operator; an electrical energy storage which provides electrical energy for the drive component; and a drawbar carrier which is carried by the upper mass and which is connected to the upper mass via a second vibration decoupling device; wherein the guide drawbar is attached to the drawbar carrier; and wherein the energy storage is mounted on the drawbar carrier.

2. The work tool according to claim 1, wherein the working component has a drive motor for the working device.

3. The work tool according to claim 1, wherein the energy storage that is carried by the drawbar carrier is a first energy storage; and wherein the drive component has a second energy storage which is arranged on the upper mass.

4. The work tool according to claim 1, wherein the drawbar carrier is arranged in a region of the upper mass which is facing an operator.

5. The work tool according to claim 1, wherein the guide drawbar is pivotally mounted relative to the drawbar carrier.

6. The work tool according to claim 1, wherein the second vibration decoupling device has multiple connection points between the drawbar carrier and the upper mass.

7. The work tool according to claim 1, wherein at least four connection points are provided between the drawbar carrier and the upper mass; and wherein three of the four connection points span an imaginary plane, and the fourth connection point has a vertical distance from the plane which corresponds at least to half the smallest distance that the fourth connection point has from the closest of the other three connection points.

8. The work tool according to claim 1, wherein six connection points are provided between the drawbar carrier and the upper mass; and wherein at least two of the six connection points are arranged at a different height plane than the remaining connection points, based on a provided use position of the work tool in a horizontal plane.

9. The work tool according to claim 1, wherein the connection points are each formed by buffer elements.

10. The work tool according to claim 9, wherein the buffer elements each have a central axis in their longest direction; and wherein the central axis of the buffer elements of all connection points extend in at least three different spatial directions.

11. The work tool according to claim 1, wherein the buffer elements are arranged in such a way that they are subjected to pressure and/or thrust during operation of the work tool, but not to tension.

12. The work tool according to claim 1, further comprising a protective frame is which is connected with the upper mass or with the drawbar carrier.

13. The work tool according to claim 1, wherein—the guide drawbar has an elongated extension; and wherein a handle bracket for—a handlebar for gripping by the operator is provided at one end of the extension facing away from the upper mass.

14. The work tool according to claim 1, wherein the work tool is a vibrating plate for soil compaction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other advantages and features of the invention are explained in more detail below using examples with the aid of figures, as follows:

(2) FIG. 1 shows a perspective top view of a vibrating plate serving as a work tool;

(3) FIG. 2 is a side view of the vibration plate of FIG. 1;

(4) FIG. 3 shows a perspective partial view of a drawbar carrier with a guide drawbar; and

(5) FIG. 4 shows a variant of the vibrating plate from FIG. 2

DETAILED DESCRIPTION

(6) FIG. 1 shows a vibration plate driven by an internal combustion engine for soil compaction as an example of a work tool according to the invention in the perspective view from above. FIG. 2 shows the vibration plate of FIG. 1 in a side view. Whereas in the representation in FIG. 2, the vibrating plate is equipped with a protective frame that will be explained later, said frame is removed from FIG. 1 for better illustration.

(7) The vibration plate has a lower mass 1 and an upper mass 2 arranged above the lower mass 1.

(8) A bottom contact plate 3 serving as a tool is considered to be a component of the bottom mass 1, the underside of which is moved over the soil to be compacted. A vibration exciter 4 is arranged on the ground contact plate 3 which can be designed, for example, as a known imbalance exciter. The unbalance exciter has, for example, two counter-rotating unbalanced shafts, on each of which an unbalanced mass is arranged. The resultant countervailing rotation creates a force vector that forms the desired vibration. Due to the rigid coupling between the vibration exciter 4 and the ground contact plate 3, the vibration is introduced directly into the ground contact plate 3 and can therefore be used well for soil compaction.

(9) Fastening devices 5 are also provided on the lower mass 1, on each of which buffer elements 6 made of a rubber or plastic material are arranged. The buffer elements 6 are part of a first vibration decoupling device which decouples the upper mass 2 in terms of vibration in relation to the lower mass 1, which vibrates strongly during operation.

(10) A protective frame 7 is arranged on the upper mass 2 as part of the upper mass 2 (FIG. 2), which, however—as mentioned above—is not shown in FIG. 1.

(11) A drive motor (not shown) for driving the vibration generator 4 is also considered to be part of the upper mass 2. In particular, this can be an internal combustion engine. However, it is also possible to implement the drive motor as an electric motor.

(12) To transmit the drive power of the drive motor to the vibration exciter 4, a transmission device, also not shown, is further provided, which can be implemented, for example, as a belt drive or as a hydraulic drive.

(13) The other components can also be included in the upper mass 2: for example, a fuel tank, control components, engine cooler, cooling fan, a centrifugal clutch, a protective frame.

(14) A drawbar carrier 8 is held at upper mass 2. For this purpose, a corresponding section 9 can be formed in the upper mass, into which the drawbar carrier 8 is inserted (FIG. 1).

(15) FIG. 3 shows the drawbar carrier 8 attached to the upper mass 2 in a perspective partial view.

(16) The drawbar carrier 8 is decoupled from the upper mass 2 in terms of vibration. For this purpose, a second vibration decoupling device is provided between the drawbar carrier 8 and the upper mass 2, which has multiple buffer elements 10. For the vibration plate shown as an example in FIGS. 1 to 3, a total of six buffer elements 10 are arranged between the upper mass 2 and the drawbar carrier 8. The buffer elements 10 are shown in respective cutaway drawings in FIG. 2.

(17) Each of these buffer elements 10 has a plate (sheet, disc, etc.) on the front-end. The actual buffer material, for example a rubber or plastic material, is arranged between the two front-end plates. Basically, the buffer elements 10 can have a similar design as the buffer elements 6 between the upper mass 2 and the lower mass 1. These are generally components that are available on the open market and commercially available, for example rubber buffers.

(18) The respective central axis of the buffer elements 10 are arranged on one side of the drawbar carrier 8 and are spaced apart from one another, as shown in FIGS. 1 to 3. The respective central axis of the buffer elements 10 extend in different spatial directions, as is clearly visible in the FIGS. 1 to 3, as well. In this way, different preferred directions of action of the buffer elements 10 are achieved in order to preferably subject the buffer elements 10 to pressure or thrust (or torsion), only, but not to tension.

(19) The drawbar carrier 8 is box-shaped and has a plateau-shaped area 11 which is delimited by side walls 12 (FIG. 3).

(20) A battery 13 is set up on the plateau-shaped area 11, the position of which is fixed by a locking element 14. In this way, the battery 13 is reliably held in its position even when the vibration plate is in operation. The battery 13 is used in particular to store and provide electrical energy which, if necessary, can be supplied to an electric starter provided on the drive motor. In addition, further control devices of the vibration plate can be supplied with electrical energy from the battery 13.

(21) If the drive motor is implemented as an electric motor in a variant, the battery 13 can also serve as part of a traction battery which supplies the electric motor with the necessary electrical drive energy. Another part of the traction battery can be provided directly on the upper mass as drawbar carrier 8, which is not—as in the battery 13—decoupled in terms of vibration from the upper mass.

(22) Because the battery 13 is mounted on the drawbar carrier 8, it is effectively decoupled from the vibrations in the lower mass 1 in terms of vibrations. The vibrations in the lower mass 1 are considerably reduced due to the first vibration decoupling device (buffer elements 6) and second vibration decoupling device (buffer elements 10) connected in series with respect to the battery 13 and the drawbar carrier 8, so that the battery 13 is well protected.

(23) On the drawbar carrier 8, a drawbar receptacle 15 is provided in the rearward area, on which a guide drawbar 16 is pivotally mounted. The lower end of the guide drawbar 16 is fastened to the drawbar receptacle 15 with its lower end and can be pivoted between an upper position and a lower position shown in the figures about a pivot axis 16a if the operator pushes a drawbar head 17 formed at the end of the guide drawbar 16 up or down.

(24) A stop device 18 with a height adjustment 19 is provided on the guide drawbar 16. A buffer element 20 is arranged at the lower end of the stop device 18 which element can be stopped against a stop 21 formed on the drawbar receptacle 15 when the guide drawbar 16 is in the lower position shown in FIG. 2.

(25) With the help of the height adjustment 19, the angle of the guide drawbar 16 can be adjusted in the lower position relative to the drawbar receptacle 15 and thus the remaining vibrating plate in order to adjust the drawbar head 17 to a comfortable height for the body size of the operator.

(26) A handlebar 22, which also serves as a switch bracket, is arranged on the drawbar head 17. Accordingly, the sturdy handlebar 22 can be gripped by the operator, on the one hand, in order to apply corresponding forces to the vibrating plate and to control and steer it. In addition, the handlebar 22—if it is also designed as a switch bracket—can be pivoted relative to the drawbar head 17. The pivoting of the handlebar 22 is detected by a transmission device, not shown, and transmitted to the vibration exciter 4. In particular, a hydraulic transmission device can be provided, with the aid of which the relative position of the unbalanced shafts in the vibration exciter 4 and thus the phase bearing thereof can be changed so as to adjust the direction of the resulting vibration vector and thus the direction of travel.

(27) In this way, a forward and backward travel of the vibration plate can be realized. The vibrating plate can also implement a stationary vibration when in standstill. The control options described have been known for a long time and therefore do not need to be explained in more detail here.

(28) FIG. 4 shows another embodiment of a vibrating plate serving as a working device according to the invention.

(29) As far as similar or structurally identical components are used, as in the embodiment of FIGS. 1 to 3, the same reference numerals are used.

(30) This vibration plate also has a lower mass 1 and an upper mass 2, a first vibration decoupling device in the form of the buffer elements 6 being provided between the lower mass 1 and the upper mass 2, in terms of operation.

(31) On the upper mass 2, a drive motor 23 is also attached and shown in FIG. 4.

(32) In this variant, the drawbar carrier 8 is designed to be significantly larger and extends over the entire base area of the upper mass 2, with cutouts also being possible. Accordingly, the drawbar carrier 8 is decoupled in terms of vibration from the upper mass 2 via the buffer elements 10, which serve as a second vibration decoupling device.

(33) In addition, a protective frame 24 is carried by the drawbar carrier which spans the vibration plate in a housing-like manner in a manner known per se. The protective frame 7 shown in FIGS. 1 to 3 is thus replaced by the protective arm.

(34) Due to the fact that the protective frame 24 is part of the drawbar carrier 8 or is rigidly attached to it, the total mass of the drawbar carrier 8 is increased, whereby the effect of the vibration reduction is further intensified. Accordingly, it is possible to considerably reduce the vibrations acting on the battery 13 supported by the drawbar carrier 8. The guide drawbar 16 is also held by the drawbar carrier 8, so that the vibrations (hand-arm vibrations) transmitted to the operator via the guide drawbar 16 can also be kept small.

(35) In a further embodiment, not shown, the battery 13 is an element of an electrical drive of the work tool. The electrical drive energy can be provided by means of a traction battery arranged on the upper mass and can be provided to the battery 13. To this extent, the battery 13 can form part of the traction battery or support it. The energy of the traction battery and battery 13 can, for example, be combined in order to provide a higher overall capacity. Alternatively, it is also conceivable to supply the electronic control with the battery 13 and to supply the electric drive motor by means of the traction battery, i.e., to assign separate tasks to both batteries. In this case, the battery 13 can also be referred to as a secondary battery, since it serves to provide energy for secondary tasks that is not directly required to operate the electric motor.