Electric hammer

Abstract

A hand-held electric hammer includes a handle arrangement on a tool carrier shank in which a striking mechanism actuated by an electric motor is accommodated and at the lower end of which a tool holder is arranged, which is suitable for receiving a tool attachment in the form of a spade blade, a demolition chisel, or a PVC scraper. The handle arrangement is designed as a T-shaped T-handle seated on the tool carrier shank, so that on both sides of the tool carrier shank there are two handles for both a left and a right hand of a user, whereby in the lower half of the tool carrier shank an additional handle stub is attached protruding in parallel with the T-handle from the tool carrier shank, which allows the electric hammer to be gripped with one hand on the T-handle and with the other hand on the additional handle stub.

Claims

1. A hand-held electric hammer comprising: a handle arrangement on a tool carrier shank in which a striking mechanism actuated by an electric motor is accommodated and at a lower end of which a tool holder is arranged, which is suitable for receiving a tool attachment designed as a spade blade and for receiving at least one further tool attachment, wherein the handle arrangement is designed as a T-shaped T-handle seated on the tool carrier shank, so that two handles for both a left and a right hand of a user are provided on both sides of the tool carrier shank, wherein an additional handle stub being attached to the tool carrier shank in a lower half which permits the electric hammer to be gripped with one hand on the T-handle and with the other hand on the additional handle stub, and wherein the additional handle stub houses the electric motor.

2. The electric hammer according to claim 1, wherein the electric hammer comprises a set of tool attachments containing the tool attachment formed as a spade blade and at least one further tool attachment.

3. The electric hammer according to claim 1, wherein an accumulator unit serving to operate the electric hammer is accommodated in the tool shank.

4. The electric hammer according to claim 1, wherein the electric hammer is designed for use as a battery-powered spade.

5. The electric hammer according to claim 1, wherein the additional handle stub is provided with ventilation openings at its free end.

6. The electric hammer according to claim 1, wherein the electric motor has an output shaft designed as a crankshaft which projects into the tool carrier shank and on whose crank axis extending eccentrically to the motor axis a connecting rod is received in a rotationally movable, which connecting rod is connected to the striking mechanism.

7. The electric hammer according to claim 1, wherein the striking mechanism acts on the tool holder, which is movably mounted on the tool carrier shank.

8. The electric hammer according to claim 1, wherein the accumulator unit consists of several lithium-ion cells or of a lithium-polymer unit.

9. The electric hammer according to claim 1, wherein for the T-shaped connection of the tool carrier shank with the two handles, a bifurcation block is provided which rests on the tool carrier shank and from which the two handles project.

10. The electric hammer according to claim 1, wherein the two handles are each equipped with an electric or electronic switch, which switches are configured for switching on/off and for setting the mode of operation of the electric hammer as a spade or another tool.

11. The electric hammer according to claim 1, wherein a charging socket for the accumulator unit located in the tool carrier shank is arranged at the free end of the left or right handle.

12. The electric hammer according to claim 1, wherein the electric hammer has a display device for indicating the charge level of the accumulator unit, the remaining running time under current load and/or other parameters.

13. The electric hammer according to claim 1, wherein for controlling the electric hammer in response to a charge state sensor determining the charge state of the accumulator unit, a control unit is provided, which is arranged inside the electric hammer above the accumulator unit.

14. The electric hammer according to claim 1, wherein the tool holder has an SDS drilling shaft system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described with reference to the drawings wherein:

(2) FIG. 1 is a perspective view of an electric hammer according to an exemplary embodiment of the invention;

(3) FIG. 2 is a view largely corresponding to FIG. 1, omitting the tool carrier shank, the T-handle and the additional handle connecting piece;

(4) FIG. 3 is a view from above, omitting the tool carrier shank, the T-handle and the additional handle socket, on the electric hammer shown in the previous figures.

(5) FIG. 4 shows a set of different tool attachments for the electric hammer shown in FIG. 1; and

(6) FIG. 5 shows a top view of the electric hammer shown in FIG. 1.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

(7) FIG. 1 shows the general construction of an electric hammer designed as a battery-operated spade according to an exemplary embodiment of the invention. In the upper area, the spade has a T-handle attached to its tool carrier shank in a T-shape. The T-handle consists of a bifurcation block 6, typically screwed onto the tool carrier shank 4, from which a handle 1 protrudes to the left and right.

(8) Both handles 1 are equipped with an electric or electronic switch 2. The switches 2 serve not only as on-off switches, but also for configuring the spade. For example, if one of the switches 2 is pressed once briefly, the speed and thus the number of strokes is set automatically optimised for excavation work. If the switch 2 is pressed twice in short succession, the number of strokes is optimally designed for demolition work. If it is pressed three times in short succession, the number of strokes is optimally configured for scraping work. The other switch 2 can then serve as an ON-OFF switch. It would also be conceivable to design both switches as ON-OFF switches and as configuration switches, so that the spade can be conveniently operated by both left-handed and right-handed users. A watchdog or dead man's switch would also be possible.

(9) At the end of the left or right handle 1 is a charging socket 3 for battery cells of an accumulator unit or an accumulator 5 located in the tool holder or main tube 4. The charging socket 3 is equipped with a rubber cap to protect against dust and splash water. Bifurcation block 6 may have a display device 18, e.g., an LCD or OLED display or other indicator on the top to indicate the charge level of battery 5 or the remaining battery life under current load or other parameters.

(10) In the lower third of the tool carrier shank 4, an additional handle stub 7 is attached. To ensure the necessary heat dissipation, the end of the additional handle stub 7 is provided with ventilation openings 9.

(11) At the lower end of the tool carrier shank 4, there is a tool holder 10, in which a tool attachment designed as a spade blade 11 is inserted. However, another tool attachment can also be fixed there, e.g. a tool attachment designed as a demolition chisel or PVC scraper, as long as it fits into the tool holder. The tool holder 10 can be designed hexagonally or equipped with the usual SDS drill shank system for striking and rotating power tools.

(12) FIG. 2 shows the main internal components of the battery-operated spade. The accumulator unit 5 can be designed as a battery pack with, for example, 44 conventional lithium-ion round cells. Conventional lithium-ion round cells are relatively inexpensive. An electric motor 8 serving as a drive unit can be designed as a brushless DC motor. If, on the other hand, an ordinary DC motor is used for cost reasons, it can be equipped with an optical, Hall effect or magneto-resistive rotary transmitter in order to continuously measure the current speed and adjust it if necessary.

(13) The electric motor 8 can directly drive an eccentric 12, namely a motor output shaft designed as a crankshaft, in order to convert the rotary movement into a longitudinal movement. The two axes of the U-shaped crankshaft, namely the eccentric 12, one of which represents the motor axis and the other a bearing axis for a connecting rod 13, can each have ball bearings.

(14) The connecting rod 13 is advantageously equipped with a shock absorber 14 to prevent damage. The connecting rod 13 is connected to striking mechanism 15. This exerts the necessary impulse on the tool holder 10, which is movably mounted.

(15) The entire control of the battery-operated spade is taken over by one or more microcontrollers forming part of a control unit 19. The control unit 19 is mounted on a board 16 above the battery 5, as shown in FIG. 3, wherein there is also a charge tate sensor 20 provided on the board 16, determining the charge state of the accumulator unit 5. The circuit board 16 is located in the bifurcation block 6, so that there is enough space for the cabling.

(16) FIG. 4 shows a set 30 of tool attachments containing the attachment formed as a spade blade 11 and another tool attachment, here formed as a demolition chisel 21.

(17) It is understood that the foregoing description is that of the exemplary embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.