Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1999-02-25
2000-04-04
Edwards, N.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428400, 30276, 30353, 30355, 30356, D02G 300, B26B 700, B26B 900, B26B 902
Patent
active
060459115
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a cutting filament intended for trimming and cutting vegetation, such a cutting filament being used on rotary-head motorized cultivators commonly called brush cutters and edge trimmers.
These implements are generally equipped with an electric motor or an engine, which drives in high-speed rotation, a revolving head supporting one or more cutting filaments. As the head rotates, and under the effect of centrifugal force, the cutting filament or filaments run out radially and thus cover a certain circular region, in which they slice through the vegetation they meet. In a known fashion, the cutting filaments may be plant-based, synthetic, metal, or metallo-plastic filaments of the mono-filament or multi-filament type, and these filaments may have either a round section or a polygonal section, for example square or in the shape of a star.
During use, such cutting filaments generate a substantial and unpleasant amount of high-frequent noise which is added to the noise of the motor for driving the rotary head. These noises lead to noise pollution which is all the more annoying since their very nature means that brush cutters and edge trimmers are being used out of doors. In addition legislatory requirements aiming to limit the noise of these implements to a level deemed to be acceptable are being drawn up and could shortly come into force.
In order to attempt to reduce the noise generated by cutting filaments during use, various solutions have already been put forward.
From U.S. Pat. No. 5,220,774 known cutting filaments having straight or helical longitudinal grooves of rounded or angular section, in varying numbers (one or more longitudinal grooves); the drawback of theses grooves is that they adversely alter the surface quality of the filament, which is an important factor in the quality of its cutting.
Another known solution, applicable especially to a cutting filament of square section, consists in twisting the filament. This solution is relatively effective, but the reduction in noise is still a function of the number of twists in cutting filament per unit length of said filament. What is more, the torsion in the filament adversely alters its surface quality; it also makes this filament more complicated and more expensive to manufacture.
Cutting filaments with a special profile in the shape of a teardrop or aerofoil have also been proposed, these profiles being supposed to improve penetration through the air. This solution allows only a quite small reduction in noise, and is therefore not particularly efficient.
Finally, mention may be made of attempts to produce cutting filaments which have small dimples at their surface, like a golf ball. Aside from the manufacturing difficulties, this last solution leads to an adverse alteration to the surface quality of the filament.
The present invention aims to avoid these drawbacks by providing an improved cutting filament which affords a substantial reduction in operating noise without adversely altering the essential properties of the filament, even improving its cutting ability which is associated with its surface quality, as well as its resistance to breaking at the eyelet, and to achieve all this with the filament still being simple and economical to produce.
To this end, the subject of the invention is a cutting filament for brush cutters and edge trimmer, characterized essentially in that it has undulations which recur in the longitudinal direction of this cutting filament and run in at least one radial direction relative to the longitudinal axis of the said cutting filament.
Thus, the solution put forward by the present invention consists, in general, in giving the cutting filament an undulated appearance. The undulations very significantly improve the coefficient of penetration of the cutting filament through the air. It is this improvement in the coefficient or penetration through air, and therefore the reduction in the impact that the filament has on the air, which generates the drop in noise, said drop may be in the order
REFERENCES:
patent: 3567569 (1971-03-01), Ono et al.
patent: 4054993 (1977-10-01), Kamp et al.
patent: 4186239 (1980-01-01), Mitz et al.
patent: 4229501 (1980-10-01), Kern
patent: 4349198 (1982-09-01), Stelek
patent: 4585487 (1986-04-01), Destree et al.
patent: 5187845 (1993-02-01), Duffy et al.
patent: 5220774 (1993-06-01), Harbeke et al.
Landen Goran
Legrand Emmanuel
Edwards N.
Husqvarna AB
LandOfFree
Cutting filament does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cutting filament, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cutting filament will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-363181