The invention relates to a power tool, in particular a pipe press, comprising a drive, a transmission device, a threaded spindle drive and a linear actuator, wherein a torque generated by the drive is transmissible via the transmission device and the threaded spindle drive to the linear actuator.
Various power tools for deformation and cutting processes are known from the prior art. By means of these special power tools, it is for example possible for reinforcement bars to be severed, for pipes to be mechanically connected or for hose clamps to be pressed on. The mechanical connection tasks also include so-called crimping, flanging and squeezing.
In order to realize the high pressing forces required for the crimping of steel pipes, for example, commercially available deformation machines have a pressing head which is driven by a pressing cylinder. Here, the pressing cylinder is commonly hydraulically driven for the purposes of moving the pressing head. An electric motor drives, in turn, a hydraulic pump, which outputs the linear movement of the pressing cylinder. Alternatively, there are also commercially available mechanical pressing, cutting and crimping tools which, instead of the hydraulics, generate the pressing pressure by means of a threaded spindle drive in combination with an electric motor. Here, the rotational movement of the electric motor is transformed by means of a threaded spindle into a linear movement to a linear actuator. These power tools commonly comprise a transmission which is connected between the threaded spindle drive and electric motor and which serves for reducing the required motor torque, in order to thus be able to dimension the motor to be smaller.
However, these power tools known from the prior art often have the problem that the electric motor is exposed to a relatively high reaction force by the pressing movement of the tool, which is embodied as a pressing head. As a result, the electric motor can be subject to severe stress, resulting, in turn, in relatively high friction torques and inefficient operation of the electric motor.
It is an object of the present invention to provide a power tool, in particular a pipe press, comprising a drive, a threaded spindle drive and a linear actuator in order to solve the above mentioned problems and, in particular, to provide a power tool having a coupling device which, when a threaded spindle drive is driven, simultaneously allows axial sliding movement, with the result that an axial change in length in the drivetrain of the power tool is compensated while a torque is being transmitted.
In particular, the present invention provides a power tool, in particular a pipe press, comprising a drive, a transmission device, a threaded spindle drive and a linear actuator, wherein a torque generated by the drive is transmissible via the transmission device and the threaded spindle drive to the linear actuator.
According to the invention, the power tool comprises a coupling device having a sleeve and a piston for converting a rotational movement generated by the transmission device into a linear movement, to be transmitted to the threaded spindle drive, from the transmission device to the threaded spindle drive, wherein a toothed profile for connecting the piston to the sleeve for conjoint rotation therewith is contained between the sleeve and the piston, with the result that the piston is arranged in a manner which allows it to move axially relative to the sleeve and to rotate with the threaded spindle drive.
According to an advantageous exemplary embodiment, the toothed profile is in the form of a multi-tooth geometry. As a result, a particularly high resistance to rotation between the sleeve and the piston can be produced. At the same time, reliable axial movement of the piston relative to the sleeve is ensured.
Further advantages will become apparent from the following description of the figures.
Various exemplary embodiments of the present invention are illustrated in the figures.
The figures, the description and the patent claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to produce useful further combinations.
In the figures, identical and similar components and assemblies are denoted by the same reference signs.
Specifically:
As can be seen in
The housing 2 of the power tool 1 is of substantially cylindrical form and comprises a front end 2a, a rear end 2b, a left-hand side surface 2c, a right-hand side surface 2d, an upper side 2e and a lower side 2f. A central part 2g of the housing 2 serves as a handgrip for allowing the power tool 1 to be held and controlled.
The energy supply 4 is positioned at the rear end 2b of the housing 2 of the power tool 1. In the present exemplary embodiment, the power supply 4 is in the form of a rechargeable battery (also referred to as power pack or battery). The power supply 4 in the form of a rechargeable battery may be detachably connected by means of an interface 5 to the rear end 2b of the housing 2 of the power tool 1. The power tool 1 or the electrical consumers of the power tool 1 is or are supplied with electrical power by means of the rechargeable battery 4.
In an alternative embodiment of the present invention, the power supply 4 of the power tool 1 may also be embodied as an electrical cable for releasably connecting the power tool 1 to an electrical grid source (that is to say electrical socket).
The tool fitting 3 for detachably receiving and holding a tool 6 is positioned at the front end 2a of the housing 2 of the power tool 1. In the present exemplary embodiment, a tool 6 in the form of a deformation tool is positioned at the tool fitting 3. In the present exemplary embodiment, the deformation tool 6 is embodied as a so-called pressing head. The deformation tool 6 embodied as a pressing head serves substantially for the processing and in particular deformation of lines, that is to say pipes and tubes. During the deformation process, it is essentially the diameter of the lines which is reduced with the aid of the tool embodied as a pressing head. The lines are not shown in the figures.
An activation switch 7 is positioned on the lower side 2f of the housing 2 of the power tool 1. The power tool 1 can be started and stopped by means of the activation switch 7.
Substantially a drive 8, a drive shaft 9, a transmission device 10, a coupling device 11, a threaded spindle drive 12 and a linear actuator 13 are positioned in the interior of the housing 2 of the power tool 1. In the present exemplary embodiment, the drive 8 is embodied as a brushless electric motor.
In the present exemplary embodiment, the transmission device 10 is embodied as an eccentric transmission device. According to an alternative embodiment, the transmission device may also be embodied in a form other than an eccentric transmission device.
As illustrated in
A rotational speed ratio between the drive 8 and the output shaft 11 can be generated by means of the transmission device 10.
As shown especially in
Moreover, the eccentric gear 15 is positioned in the ring gear 16. The ring gear 16 is connected to the inside of the housing 2 of the power tool 1 in a manner which prevents rotation relative to said housing. The eccentric gear 15 and the ring gear 16 have involute toothing 20, cf.
Furthermore, the eccentric gear 15 contains a number of apertures 21 arranged in a circle around the drive eccentric 14. In the exemplary embodiment which is shown in the figures, the apertures 21 are in the form of eleven through holes. However, there may also be more or fewer than eleven through holes. According to an alternative embodiment, the apertures 21 can also be formed as blind holes. The blind holes are arranged in such a way that the respective closed end of a blind hole is arranged counter to arrow direction A, and the open end of the blind hole faces in arrow direction A.
In the present exemplary embodiment, the compensating coupling 17 is embodied as a parallel crank coupling with coupling elements 22. Each of the through holes 21 of the eccentric gear 15 serves to receive a coupling element 22. In the present exemplary embodiment, the coupling elements 22 are embodied as coupling pins.
The compensating coupling 17 may therefore be referred to as a parallel crank coupling or alternatively as a pin or crank coupling.
As can likewise be seen in
The coupling device 11 has a substantially cylindrical shape and comprises a sleeve 11a and a piston 11b (see,
As can be seen in
A toothed profile 31 (see, e.g,
By virtue of the toothed profile 31 between the outer wall AW (see, e.g,
With the aid of a main bearing 23 and a secondary bearing 24 (see, e. g.,
As already described above, the coupling device 11 is connected to the compensating coupling 17 of the transmission device 10 (see, e.g,
As can be seen from the figures, the threaded spindle drive 12 is connected to the linear actuator 13 (see, e.g,
By virtue of the rotational movement of the drive shaft 9 in direction of rotation R around the axis of rotation N, the sleeve 11a and the piston 11b, inter alia, likewise rotate in direction of rotation R around the axis of rotation N, as a result of which the piston 11b is pushed in arrow direction A.
In
In
The linear actuator 13 comprises substantially a compression spring 25 and a thrust rod 26. Here, the compression spring 25 acts as a restoring spring for the linear actuator 13. (See, e.g,
A force flow diverting device 27 is provided at the linear actuator 13. By means of the linear actuator 13 and the force flow diverting device 27, the linear force of the linear actuator 13 is transmitted to the tool fitting 3 such that the tool 6 in the form of a pressing head can be moved between an open and a closed position.
The drive 8, which is embodied as an electric motor, can rotate with a rotational speed value of between 10 000 and 30 000 rpm at a maximum extension and retraction speed of the linear actuator 13. In particular, a rotational speed value of between 15 000 and 18 000 rpm is provided for the drive 8.
1 Power tool
2 Housing
2
a Front end 2a of the housing
2
b Rear end of the housing
2
c Left-hand side surface of the housing
2
d Right-hand side surface of the housing
2
e Upper side of the housing
2
f Lower side of the housing
3 Tool fitting
4 Power supply
5 Interface
6 Tool
7 Activation switch
8 Drive
9 Drive shaft
10 Transmission device
11 Coupling device
11
a Piston
11
b Sleeve
12 Threaded spindle drive
13 Linear actuator
14 Drive eccentric
15 Eccentric gear
15
a Aperture in the eccentric gear
16 Ring gear
17 Compensating coupling
18 Compensating weight
19 Ball bearing
20 Involute toothing
21 Apertures in the eccentric gear
22 Coupling element
22
a Free end on the coupling element
23 Main bearing
24 Secondary bearing
25 Compression spring
26 Thrust rod
27 Force flow diverting device
30 Bearing
31 Toothed profile
32 First end of the sleeve
33 Second end of the sleeve
34 First end of the piston
35 Second end of the piston
36 Gear element
AW Outer wall of the piston
IW Inner wall of the sleeve
Z Teeth of the toothed profile
Number | Date | Country | Kind |
---|---|---|---|
20210522.7 | Nov 2020 | EP | regional |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2021/081503 | 11/12/2021 | WO |