US 6,314,649 B1 · Work apparatus

Abstract

The invention relates to the assembly of a shaft bearing (16) in the end section (6) of a guide tube (5) of a brushcutter (1). The guide tube (5) accommodates a drive shaft. The bearing (16) is axially inserted into the end section (6) and is held so that it cannot separate therefrom. The outer diameter (DM) of the outer surface (18) of the bearing (16) is configured smaller than the inner diameter (DI) of the end section (6) in order to facilitate assembly and to ensure a force-tight inseparable seating of the bearing 16 in the end section. Several axial ribs (19, 20, 21) are distributed uniformly over the periphery of the outer surface (18). The radial elevation (H) of the axial ribs is slightly greater than approximately half the difference between the inner diameter (DI) of the end section (6) and the outer diameter (DM) of the surface (18) of the bearing (16). To mount the bearing (16), the end section is elastically deformed so far until the diameter (DV) is slightly greater than the axial maximum outer diameter (24) of the bearing (16). The diameter (DV) is measured from a corner (27) and the maximum outer diameter (24) is determined by the radial height (H) of the axial ribs (19, 20, 21). The end section (6) returns elastically in the direction toward its initial form after the axial insertion of the bearing (16). The bearing (16) is then surrounded force tight by the end section (6).

Claims20

Dependent claims

A work apparatus comprising:

a drive motor;
a guide tube having an end connected to said drive motor and having an end section facing away from said drive motor;
a rotatably driven work tool mounted on said end section;
a drive shaft rotatably journalled in said guide tube and connecting said drive motor to said work tool so as to permit said drive motor to rotatably drive said work tool;
said end section defining a longitudinal axis and having an interior space;
said end section further having an inner diameter (DI) before being formed;
a bearing axially inserted into said interior space for mounting said work tool on said end section;
said bearing having an outer surface and a plurality of axial ribs formed on said outer surface;
said axial ribs having respective rib roofs conjointly defining an imaginary cylinder having an outer diameter greater than said inner diameter (DI) of said end section;
said bearing having an outer shape when viewed in cross section characterized by said outer surface with said axial ribs;
and,
said end section of said guide tube being elastically formed to assume a shape corresponding to said outer shape of said bearing for surroundingly force tightly holding said bearing.

9 more elements

A method for axially assembling a bearing in an end section of a guide tube which approximately concentrically surrounds a drive shaft, the end section having a longitudinal center axis and having an inner diameter (DI) before being formed;

said bearing having an outer surface and a plurality of axial ribs formed on said outer surface;
said axial ribs having respective rib roofs conjointly defining an imaginary cylinder having an outer diameter greater than said inner diameter (DI) of said end section;
the method comprising the steps of:
essentially elastically deforming said end section by clamping said end section between clamping jaws so that a cornered cross-sectional shape is imparted to said end section with said clamping jaws being applied until said cornered cross-sectional shape has a diameter (DV) measured from a corner which is slightly greater than a distance measured between a rib roof of one of said axial ribs and a diametrically opposite lying outer wall surface of said bearing through said longitudinal center axis;
after reaching said diameter (DV), pushing said bearing into said end section in such a rotational position substantially without force so that said axial ribs come to rest in corresponding ones of said corners of the deformed end section;
and,
allowing the elasticity forces of the material of said end section to return deform said end section by loosening said clamping jaws so that said end section comes into force-tight contact engagement with said axial ribs.

4 more elements

Dependencies are inferred from the claim text.

Work apparatus

Life of this patent

Work apparatus

Life of this patent

Abstract

Claims20