Granted Patent B2

US 12,582,029 · App. 17/855,113 · Granted Mar 24, 2026

Inventors: Beth E. Cholst (Wauwatosa, WI); Troy C. Thorson (Cedarburg, WI)

Assignee: Milwaukee Electric Tool Corporation

A01D34/4166A01D34/4167

Abstract

Claims (40)

1 . A trimmer head for use with a string trimmer including a drive shaft, the trimmer head comprising:

a housing rotatable about a rotational axis, the housing including a main body defining a cavity, and a cap removably coupled to the main body;

a spool supported in the cavity and operable to support line to be dispensed;

a retainer positioned between the cap of the housing and the spool, the retainer including a ring, a first series of teeth extending from an upper surface of the ring towards the cap, and a second series of teeth extending from a lower surface of the ring towards the spool; and

a nut positioned within the spool and configured to drivingly couple to the drive shaft.

2 . The trimmer head of claim 1 , wherein the cap is keyed to the nut.

3 . The trimmer head of claim 2 , wherein the spool is rotationally and axially fixed to the cap via the nut.

4 . The trimmer head of claim 1 , wherein the nut protrudes through the spool and is received within a central boss of the housing.

5 . The trimmer head of claim 1 , wherein the nut includes a first aperture and the spool includes a second aperture, wherein the first aperture and the second aperture at least partially define a passageway for a line to be fed through the trimmer head.

6 . The trimmer head of claim 1 , wherein the nut is threadably coupled to the drive shaft.

7 . The trimmer head of claim 1 , further comprising a biasing member supported in the cavity adjacent the spool.

8 . The trimmer head of claim 1 , wherein a first plurality of gaps are defined between the first series of teeth and a second plurality of gaps are defined between the second series of teeth, and wherein the first plurality of gaps are configured to receive a first plurality of teeth extending from the cap and the second plurality of gaps are configured to receive a second plurality of teeth extending from the spool.

9 . A string trimmer comprising:

a shaft;

a handle positioned on the shaft and including a grip graspable by a user;

a motor housing positioned on the shaft;

a motor positioned within the motor housing and defining a drive shaft; and

a trimmer head removably coupled to the drive shaft, the trimmer head including

a housing including a main body and a cap defining a cavity and rotatable about a rotational axis,

a spool supported in the cavity and operable to support line to be dispensed,

a retainer positioned between the cap of the housing and the spool, the retainer including a ring, a first series of teeth extending from an upper surface of the ring towards the cap, and a second series of teeth extending from a lower surface of the ring towards the spool, and

a nut positioned within the spool and drivingly coupled to the drive shaft.

10 . The string trimmer of claim 9 , wherein the trimmer head includes a biasing member supported in the cavity adjacent the spool.

11 . The string trimmer of claim 9 , wherein the housing includes a main body defining the cavity, and the cap is removably coupled to the main body.

12 . The string trimmer of claim 11 , wherein the cap is keyed to the nut, and wherein the spool is rotationally and axially fixed to the cap via the nut.

13 . The string trimmer of claim 9 , wherein the nut protrudes through the spool and is received within a central boss of the housing.

14 . The string trimmer of claim 9 , wherein the nut includes a first aperture and the spool includes a second aperture, wherein the first aperture and the second aperture at least partially define a passageway for a line to be fed through the trimmer head.

15 . A trimmer head for use with a string trimmer including a drive shaft, the trimmer head comprising:

a housing rotatable about a rotational axis, the housing including:

a main body defining a cavity, and

a cap defining a first surface and a second surface opposite the first surface, wherein the second surface includes a first plurality of teeth;

a spool supported in the cavity and operable to support line to be dispensed, the spool is drivingly coupled to the drive shaft, wherein the spool includes:

a central portion extending along the rotational axis,

a first flange proximate one end of the central portion and including a second plurality of teeth, and

a second flange proximate an opposite end of the central portion; and

a retainer positioned between the housing and the spool, the retainer including a ring, a first series of teeth extending from an upper surface of the ring towards the cap, and a second series of teeth extending from a lower surface of the ring towards the spool.

16 . The trimmer head of claim 15 , further comprising a nut insert molded into the spool, wherein the nut is drivingly coupled to the drive shaft.

17 . The trimmer head of claim 15 , further comprising a biasing member supported in the cavity and positioned adjacent to the second flange of the spool, wherein the biasing member is configured to bias the spool into engagement with the retainer.

18 . The trimmer head of claim 17 , wherein when the spool is biased into engagement with the retainer, the second plurality of teeth on the spool engage gaps defined between the second series of teeth of the retainer.

19 . The trimmer head of claim 17 , wherein when the spool is biased out of engagement with the retainer, the first plurality of teeth on the cap engage gaps defined between the first series of teeth of the retainer.

Assignments (1)

Continuity (3)

References Cited (400)