The instant application should be granted the priority date of Oct. 29, 2005 the filing date of the corresponding German patent application 10 2005 051 886.9.
The present invention relates to a manually guided implement such as a brushcutter, a trimmer, a pole pruner, or the like.
U.S. Pat. No. 5,896,669 discloses an overhead branch cutter according to which the guide rod connects the housing of the implement, in which the drive motor is disposed, with the gear mechanism housing of the implement. The tool is disposed on the gear mechanism housing, which is secured to the guide rod by means of a clamping connection. The gear mechanism housing is connected with the guide rod in an electrically conductive manner.
When working with an implement having a driven tool, electrical lines from the tool can become damaged or severed. Electrical devices have safety devices that, if damage or severance of an electrical line occurs, interrupts the supply of current, so that injury to the operator is prevented. However, in rare cases even such safety devices can become damaged or can fail.
It is therefore an object of the present invention to provide a manually guided implement of the aforementioned general type that further increases the safety of the operator.
This object, and other objects and advantages of the present invention, will appear more clearly from the following specification in conjunction with the accompanying schematic drawings, in which:
The manually-guided implement having a tool pursuant to the present application comprises a guide rod, a drive motor for driving the tool, wherein the drive motor is disposed on a first end of the guide rod and the tool is disposed in the region of a second opposite end of the guide rod, a housing disposed on the guide rod at the second end, and, for avoiding an electrical charging of the guide rod, an electrical insulator disposed between the housing and the second end.
Due to the presence of the electrical insulator between the housing at the second end of the guide rod, and the guide rod, a transfer of charges from the housing to the guide rod is avoided. As a result, even if the safety device fails due to being severed or because the electrical line is damaged, a transfer of electrical charges to the guide rod can be avoided. Even if the operator of the implement grasps the guide rod instead of the handle, or accidentally contacts the guide rod, a transfer of electrical charges to the operator is avoided since the guide rod itself is electrically insulated from the gear mechanism housing in the tool. This provides as great a safety for the operator as possible.
The housing at second end of the guide rod is preferably a gear mechanism housing in which is disposed a gear mechanism for transferring the drive movement generated by the drive motor to the tool. With such implements it is customary to transfer the drive movement through the guide rod via a drive shaft that is mounted in the guide rod. To convert the drive movement into the drive movement needed by the tool, for example a rotational movement in a direction transverse to the longitudinal direction of the drive shaft, the gear mechanism disposed in the gear mechanism housing is provided. As a result, the drive movement can easily be transferred through the guide rod. The housing is expediently held on the second end of the guide rod by means of a clamping connection. This results in a straightforward configuration. An adequate support of the housing and of the tool on the guide rod can be ensured, so that the housing is fixed on the guide rod and cannot move relative to the guide rod.
So that the clamping force can be reliably transferred via the insulator from the housing to the guide rod, and so that the electrical insulator has an adequate strength, the electrical insulator can be made of a polymeric material, especially glass fiber reinforced polymeric material. The glass fiber content is in particular approximately 30%. Due to the glass fiber content, a creeping of the electrical insulator under load can also be avoided, thereby ensuring the long-time stability of the clamping connection on the electrical insulator.
A straightforward configuration can be achieved if the electrical insulator is formed by an insulating sleeve. In this connection, the insulating sleeve has a cylindrical inner surface and a cylindrical outer surface, as a result of which a good strength of the tolerance-sensitive clamping connection between the housing and the guide rod can be ensured. The insulating sleeve is preferably disposed in a receiver in the housing, whereby the second end of the guide rod extends into the insulating sleeve.
The insulating sleeve is preferably formed of two half shells. As a result, the cylindrical shape can be ensured, especially when the insulating sleeve is produced from polymeric material. At the same time, it is easy to remove the two half shelves from the molds, so that manufacturing is simplified and there is no need for additional cores. The two half shells are preferably embodied as identical components, so that only a single mold is required to produce the insulating sleeve, and the inventory is reduced. By constructing the insulating sleeve from two identical half shells, a good accuracy to size of the cylindrical insulating sleeve can be achieved, and low tolerances can be maintained. To fix the position of the two half shells of the insulating sleeves relative to one another, the half shells can overlap in the circumferential direction. One half shell, on at least one longitudinal side that extends parallel to the longitudinal central axis of the insulating sleeve, is preferably provided with a recess that extends parallel to the longitudinal central axis, and the other half shell, on the associated longitudinal side is provided with an edge that extends parallel to the longitudinal central axis, whereby the edge of the one half shell projects into the recess of the other half shell. Where the half shells have an identical construction, each half shell has one edge and one recess, whereby an edge of one half shell respectively projects into the recess of the other half shell.
The insulating sleeve expediently has means to fix the position of the insulating sleeve relative to the housing. As a result, the position in the housing can be fixed in a straightforward manner without requiring additional components. Even during installation a correct positioning of the components relative to one another is thereby ensured. The insulating sleeve can be provided with a collar that limits the depth of insertion of the insulating sleeve into the housing. In this connection, the collar is in particular disposed on the front side of the housing. The insulating sleeve is expediently held in the housing in the direction of its longitudinal central axis by means of an arresting connection. The arresting connection in particular prevents movement of the insulating sleeve out of the housing, so that the position of the insulating sleeve, in the direction of its longitudinal central, is fixed by the collar and the arresting connection. To fix the rotational position of the insulating sleeve in the housing, the insulating sleeve is advantageously provided with a longitudinal rib that cooperates with the housing. To fix the position of the insulating sleeve on the guide rod, the insulating sleeve can have a shoulder that forms an abutment for the guide rod. As a result, the relative position of the gear mechanism housing to the guide rod is also fixed by means of the insulating sleeve. The present application is in particular provided for implements where the drive motor is an electric motor, where a severance of the connection cable of the implement can occur.
Further specific features of the present application will be described in detail subsequently.
Referring now to the drawings in detail, in
The gear mechanism housing 7 is illustrated in an enlarged view in
The insulating sleeve 10 is formed of two half shells 11, 12 that rest against one another approximately in the plane of separation between the half shells 13 and 14 of the gear mechanism housing 7. As a result, the first half shell 11 is disposed essentially in the first half shell 13 of the gear mechanism housing 7 and the second half shell 12 is disposed essentially in the second half shell 14 of the gear mechanism housing 7. The two half shells 11 and 12 of the insulating sleeve 10 are identical, in other words, are embodied as identical components. The identical half shells 11, 12 have an outwardly projecting collar 15 that rests against the gear mechanism housing 7 on that side that faces the motor housing 2 of the trimmer 1; the depth of insertion of the insulting sleeve 10 into the gear mechanism housing 7 is limited. At the opposite end the two half shells 11 and 12 of the insulating sleeve 10 have an inwardly projecting shoulder 16 that limits the depth of insertion of the guide rod 5 into the insulating sleeve 10.
The two half shells 11, 12 of the insulating sleeve 10 overlap one another in the peripheral direction in the region of the plane of separation. For this purpose, the first half shell 11 has an inner longitudinal edge 22 that extends in the longitudinal direction of the insulating sleeve 10. Adjacent to the inner longitudinal edge 22, the second half shell 12 has an outer longitudinal edge 21 that rests against the inner longitudinal edge 22 radially outwardly of the inner longitudinal edge. On the opposite side, the second half shell 12 has an inner longitudinal edge 20 that rests against an outer longitudinal edge 23 of the first half shell 11. As a result, the two half shells 11 and 12 are secured relative to one another in a radial direction. Since the two half shells 11, 12 have an identical configuration, the two inner longitudinal edges 20 and 22, and the two outer longitudinal edges 21 and 23, respectively correspond to one another.
For the clamping connection 48, via which the gear mechanism housing 7 is fixed in position on the guide rod 5, the first half shell 13 of the sleeve-like portion 26 has four jaws 27 that are fixed on the sleeve-like portion 26 and extend outwardly. In this connection, two jaws are disposed on each side of the insulating sleeve 10. Relative to the plane of the longitudinal slot 56, four jaws 28 are fixed in position in the second half shell 14 symmetrical to and opposite from the jaws 27. The jaws 27 are provided with securement bores 25, and the jaws 28 are provided with securement bores 24. Tightening screws, which are not shown in
The insulating sleeve 10 is expediently made of a polymeric material, especially PA 66 which is reinforced with glass fibers. The glass fiber content is expediently approximately 30%. In this way, a high mechanical strength for the insulating sleeve 10 is achieved, thus preventing creeping of the material during operation. This ensures that the gear mechanism housing 7 is fixedly disposed on the guide rod 5.
FIGS. 3 to 9 show the construction of the second half shell 12 in detail. The first half shell 11 is identical in construction to the second half shell 12. As shown in
As schematically shown in
As shown in FIGS. 4 to 9, the half shell 12 is provided on its longitudinal side 33, which is disposed toward the front in
The opposite longitudinal side 32 of the second half shell 12 has the inner longitudinal edge 20, which extends parallel to the longitudinal central axis 29 over nearly the entire length of the half shell 12; the longitudinal edge 20 continues in an edge section 47 at the annular shoulder 16. Formed radially beyond the inner longitudinal edge 20 is a longitudinal recess 34 that, as shown in
As shown in the cross-sectional view of
As shown in
Since the two half shells 11 and 12 of the insulating sleeve 10 are designed as identical components, the description of the second half shell 12 also pertains to the identical first half shell 11. Due to the fact that a respective longitudinal edge of one half shell cooperates with a recess of the other half shell, a construction having identical components is possible.
The specification incorporates by reference the disclosure of German priority document 10 2005 051 886.9 filed Oct. 29, 2005.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
Number | Date | Country | Kind |
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10 2005 051 886.9 | Oct 2005 | DE | national |