CUTTING HEAD FOR A STRING TRIMMER

• US 20170354090A1
• Filed: 06/14/2016
• Published: 12/14/2017
• Est. Priority Date: 06/14/2016
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: PALERMO, John
• Granted Patent: US 10,034,422 B2
• Time in Patent Office: Days
• CPC Class Codes: A01D 34/4162 automatically
• CPC Class Codes: A01D 34/4163 by triggered line feedout, e.g. bump-feeding
• CPC Class Codes: A01D 34/4167 Protection devices

Abstract

The present invention is directed to a string trimmer line feeding mechanism having a sliding lever that locks a spool relative to the spool housing, and only feeds additional cutting line when the user actuates a button. This brakes a motor, which generates a force acting on the spool to move the lever into an unlocked position, allowing the spool to rotate relative to the spool housing and feed additional cutting line.

Claims

1. A string trimmer tool comprising:

a shaft having a handle on one end thereof and a working head on an opposite end;

the working head including a spool assembly having a spool housing, a spool, a spool cap and a lever;

a motor operatively connected to rotate the spool assembly;

the spool housing and spool cap being coupled together to define an interior space and housing a spool with cutting line wound thereon;

the lever being movable between a retracted position and an extended position, and in both positions the lever rotationally locks the spool relative to the spool housing or spool cap, and during the transition of the lever between these two positions the spool is in an unlocked state so that it is free to rotate and feed out additional cutting line;

wherein the lever includes a locking means to lock the lever in either the retracted or extended position.

2. The string trimmer tool according to claim 1, wherein the locking means is a peg, and one of the spool housing or spool cap includes a slot for engaging the peg to lock the lever in one of the extended or retracted position.

3. The string trimmer tool according to claim 2, further including a spring biasing the lever into one of the extended or retracted position, wherein the lever moves into the other extended or retracted position when the spool assembly is rotating, and the lever is locked in the other extended or retracted position by the slot.

4. The string trimmer tool according to claim 3, wherein the slot is L-shaped and rotation of the spool assembly moves the peg into an arm of the slot to lock the lever in the extended or retracted position.

5. The string trimmer tool according to claim 4, wherein the arm of the slot has a depth less than the width of the peg, to prevent the entirety of the peg from residing in the arm when locked.

6. The string trimmer tool according to claim 1, wherein the spool includes a track having troughs, and the lever includes posts that move within the track and engage the troughs when the lever is in both the extended and retracted position to lock the spool.

7. The string trimmer tool according to claim 1, wherein the lever includes an opening to accommodate an axle of the spool cap or spool housing.

8. The string trimmer tool according to claim 1, wherein one of the spool cap or spool housing includes interior walls to guide translational movement of the lever.

9. The string trimmer tool according to claim 7, wherein clearance space is provided between the interior walls and the lever so that the lever can rotate.

10. A string trimmer tool comprising:

a shaft having a handle on one end thereof and a working head on an opposite end;

the working head including a spool assembly having a spool housing, a spool, a spool cap and a lever;

a motor operatively connected to rotate the spool assembly;

the spool housing and spool cap being coupled together to define an interior space, the spool and lever being housed in said interior space, the spool having cutting line wound thereon;

wherein the lever is movable within the interior space between a retracted position and an extended position, and in both positions the lever rotationally locks the spool from rotating, and during the transition of the lever between the retracted and extended position the lever is in an unlocked state so that the spool is free to rotate to feed out additional cutting line;

wherein the lever includes a peg, and one of the spool housing or spool cap includes a slot for engaging the peg to lock the lever in one of the extended or retracted position.

11. The string trimmer tool according to claim 10, further including a spring for biasing the lever into the retraced position, wherein the lever moves into the extended position when the spool assembly is rotating, and the lever is locked in the extended position by the slot.

12. The string trimmer tool according to claim 11, wherein the slot is L-shaped and rotational forces move the peg into an arm of the slot to lock the lever in the extended position, and wherein the arm of the slot has a depth less than the width of the peg, to prevent the entirety of the peg from residing in the arm when locked.

13. The string trimmer tool according to claim 12, wherein one of the spool cap or spool housing includes interior walls confining the lever, the walls being spaced from the lever to allow the lever peg to rotate into the slot.

14. The string trimmer tool according to claim 12, wherein the spool includes a track having a series of inner troughs and outer troughs, and the lever includes at least one post that rides within the track and engages the inner and outer troughs to prevent the spool from rotating.

15. The string trimmer tool according to claim 10, wherein the lever includes an opening to accommodate an axle of the spool cap or spool housing.

16. A method of releasing cutting line from a string trimmer comprising the steps:

providing a string trimmer having a working head including a spool assembly and a motor operatively connected to the spool assembly to rotate the spool assembly, the spool assembly having a spool housing and a spool cap that are coupled together to define an interior space, a spool having cutting line thereon and a lever housed in said interior space;

wherein the lever is movable between a retracted and extended position, and in both positions, locking the spool to prevent rotation;

wherein when the motor is not energized, a spring biases the lever in one of a retracted or extended position;

energizing the motor to rotate the spool assembly and move the lever into the other of the retracted or extended position, the lever having a peg that engages a slot in one of the spool cap or spool housing to lock the lever in the retracted or extended position, wherein the transition of the lever between its retraced and extended position unlocks the spool allowing it to rotate and feed out cutting line.

17. The method of releasing cutting line from a string trimmer according to claim 16, further comprising the step:

de-energizing the motor and allowing the spool assembly to gradually reduce its rotational speed at a first speed reduction rate, wherein at the first speed reduction rate the slot retains the peg and keeps the lever in the locked position so that the spool is prevented from rotating and feeding cutting line.

18. The method of releasing cutting line from a string trimmer according to claim 17, further comprising the step:

actuating a button on the string trimmer that forceably brakes the motor to reduce its rotational speed at a second speed reduction rate, which is faster than the first speed reduction rate, the braking of the motor freeing the peg from the slot so that the lever moves from one of the retracted or extended position to the other of retracted or extended position, and allowing the spool to rotate and feed cutting line.