String trimmer head

Details String trimmer head String trimmer head

2000-12-20

2002-02-19

Payer, Hwei-Slu (Department: 3724)

Cutlery

Cutting tools

With blade moving means

C030S347000, C056S012700, C056S295000

Reexamination Certificate

active

06347455

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved head for a string trimmer of the type which does not use a spooled or coiled supply of string.
2. Prior Art
String trimmers are well known wherein a spool or coil of string is retained within the head of the trimmer. Such arrangement requires that the head be disassembled when a new supply of string becomes necessary. Additionally, when the string breaks, the head often must be disassembled in order to correct the problem and to adjust the string supply for resumption of operation. Such disassembly of the head is cumbersome and requires a certain amount of dexterity by the operator of the trimmer.
To overcome deficiencies of the type just described, attempts have been made to supply string to a trimmer head from outside the head.
An example of such an arrangement is disclosed in U.S. Pat. No. 5,758,424 wherein a pair of spring-loaded cams are disposed within the trimmer head at locations adjacent openings in the sidewall of the head through which string ends may be inserted. The sidewall includes an inwardly extending deflection at each opening towards which the respective cams are urged by their springs. As a result, a string passing through an opening is pressed against a sidewall deflection by the associated cam to retain the string.
SUMMARY OF THE INVENTION
The present invention represents an improvement over the arrangement disclosed in the aforesaid U.S. Pat. No. 5,758,424 by providing an arrangement wherein the string is more easily inserted or removed from the trimmer head and is more securely held in operation position. The arrangement also permits simplified removal of broken string, is more durable than known arrangements and minimizes wear on the string during operation.
More particularly, the improved arrangement employs a pair of clamping jaws for each strand of string to be held by the trimmer head. A slidable actuator is associated with each pair of jaws. Each actuator is easily accessible to the operator to permit the jaws pairs to be selectively opened and closed. This feature is particularly useful when worn or broken string is being replaced. Also, the actuators may be used when inserting a new length of string into the trimmer head.


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