Trimming machine head and line type trimmer

Abstract

A trimmer head and a wire trimmer, the trimmer head for use with a wire trimmer comprising a drive shaft, the trimmer head comprising a housing rotatable about an axis of rotation. The housing includes a body defining a cavity, and a cover removably coupled to the body. The trimmer head further includes a spool supported in the cavity and operable to support a thread to be dispensed, a retainer positioned between the housing and the spool, and a nut positioned within the spool and configured to be drivingly coupled to the drive shaft.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 241,197 filed on September 7, 2021 and U.S. Provisional Patent Application No. 63 / 216,817 filed on June 30, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to string trimmers, and more particularly to a string trimmer head. Background Art

[0004] Generally, string trimmers are used to cut grass and weeds, and are often used to trim around trees, near fences and walls, and along landscape borders. Conventional string trimmers include an elongated shaft with a rotating element or rotating head near the end of the elongated shaft, and a spool or spool head attached to a gear head. Typically, the spool head includes a monofilament line (i.e., a trimmer line) that rotates through the head for cutting and trimming along landscape areas, fences, walls, etc. Utility Model Content

[0005] In an independent aspect, a trimmer head for use with a string trimmer including a drive shaft includes: a housing rotatable about a rotational axis, the housing including a body defining a cavity, and a cover removably coupled to the body; a spool supported in the cavity and operable to support string to be dispensed; a retainer positioned between the housing and the spool; and a nut positioned within the spool and configured to be drivingly coupled to the drive shaft.

[0006] In some embodiments, 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 passage for line to be fed through the trimmer head.

[0007] In some embodiments, the trimmer head further includes a biasing member supported in the cavity adjacent the spool.

[0008] In another independent aspect, a string trimmer includes 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 defining a cavity and rotatable about a rotational axis, a spool supported in the cavity and operable to support string to be dispensed, and a nut insert molded into the spool and drivingly coupled to the drive shaft.

[0009] In some embodiments, the trimmer head includes a biasing member supported in the cavity adjacent the spool.

[0010] In some embodiments, 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 passage for line to be fed through the trimmer head.

[0011] In another independent aspect, a trimmer head for use with a string trimmer including a drive shaft includes: a housing rotatable about a rotational axis, the housing including a body defining a cavity, and a cover 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 a string to be dispensed, the spool drivingly coupled to the drive shaft, wherein the spool includes a central portion extending along the 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 first surface having a third plurality of teeth configured to engage the first plurality of teeth and a second surface having a fourth plurality of teeth configured to engage the second plurality of teeth.

[0012] In some embodiments, the trimmer head further includes a biasing member supported in the cavity and positioned adjacent the second flange of the spool, wherein the biasing member is configured to bias the spool into engagement with the retainer.

[0013] Other independent aspects of the invention may become apparent by consideration of the detailed description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a perspective view of a string trimmer according to an embodiment disclosed herein.

[0015] Figure 2 is a perspective view of a trimmer head according to embodiments disclosed herein.

[0016] Figure 3 yes Figure 1 Cross-sectional view of the trimmer head.

[0017] Figure 4 yes Figure 1 Exploded perspective view of the trimmer head.

[0018] Figure 5 yes Figure 1 A perspective view of the main body of the trimmer head.

[0019] Fig. 6A yes Figure 1 A three-dimensional view of the eyelet of the trimmer head.

[0020] Figure 6B yes Figure 1 Another perspective view of the eyelet of the trimmer head. DETAILED DESCRIPTION

[0021] Before explaining any independent embodiment of the present disclosure in detail, it should be understood that the application of the present invention is not limited to the construction details and component arrangements set forth in the following description or shown in the following drawings. The present invention can have other independent embodiments and can be implemented or executed in various ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered restrictive.

[0022] Figures 2 to 4 An exemplary string trimmer 1 ( Figure 1 ) on a string trimmer head 10. Such a trimmer 1 generally comprises a shaft 2 having a handle 4 towards one end, and a motor housing 6 or drive shaft 5, the shaft having a handle 4 towards one end, the motor housing enclosing an electric motor 8 having a motor drive output, the drive shaft being for connecting to the trimmer head 10 on the other end. A variety of powered trimmers (e.g., battery-powered trimmers, gas-powered trimmers, etc.) may be used with the trimmer head 10.

[0023] like Figures 2 to 4 As shown, the illustrated trimmer head 10 includes a housing 14 rotatable about an axis A, and a spool 18 for holding one or more wires. The wire is wound on the spool 18 and extends through opposing holes 22 to cut vegetation (e.g., grass, weeds, etc.). In the illustrated embodiment, the trimmer head 10 is mounted to the trimmer drive shaft 5 via the spool 18. In other words, the spool 18 is drivingly connected to the drive shaft. In particular, a nut 26 configured to be drivingly connected to the drive shaft 5 can be insert-molded into the spool 18. However, in some embodiments, the nut 26 can alternatively be fixed to the spool 18 via alternative fastening methods (e.g., press fit, sliding fit with a retaining ring, etc.).

[0024] The housing 14 includes a body 30 and a top plate or cover 34. The top plate 34 is spaced above the spool 18 and is keyed to the nut 26. Thus, the spool 18 and the top plate 34 are rotatably and axially fixed to each other via the nut 26. The body 30 defines a cavity 38 for receiving the spool 18. A retainer ring 42 is positioned at the upper end of the body 30. The retainer ring 42 is located on the nut 26 and is captured between the top plate 34 and the upper end of the spool 18 with axial and rotational play. A spring is located at the lower end of the spool 18 to bias against the lower end of the housing 14.

[0025] Continue to refer Figure 3The nut 26 minimizes overall vibration within the trimmer head 10 during operation. As described above, the various components of the housing 14 (e.g., top plate 34, spool 18, retainer ring 42) are all coupled to the nut 26. As a result, the clearances between the housing components are minimized, thereby reducing overall vibration in the trimmer head 10.

[0026] In the illustrated embodiment, the top plate 34 is generally cylindrical and includes a central boss 46 having an aperture 50 extending through the boss 46. The aperture 50 is shaped and sized to fixedly receive the nut 26. An outer rim 54 of the top plate 34 covers one end of a side wall 58 of the body 30 to enclose the cavity 38. A series of teeth 60 are positioned on the inner surface of the top plate 34 and are engageable with a series of corresponding teeth positioned on the retainer 42.

[0027] The body 30 is generally cylindrical and includes a first end 30a, a second end 30b opposite the first end 30a, and a longitudinal axis 62 extending from the first end 30a to the second end 30b. The longitudinal axis 62 is colinear with the rotation axis A. The body 30 also includes a side wall 58 and a base wall 70. The side wall 58 defines a pair of eyelet openings 74 and a pair of retainer openings 78. The eyelet openings 74 are shaped and sized to receive the eyelet 22, and the retainer openings 78 are shaped and sized to receive at least a portion of the retainer 42. The inner surface of the base wall 70 includes a central boss 82 and one or more ribs 86. The central boss 82 is shaped and sized to receive a portion of the nut 26. The rib 86 extends axially from the base wall 70 and is configured to interface with the spool 18.

[0028] refer to Figures 4 to 5, an edge 90 is formed on the outer surface of the body 30 at the junction between the side wall 58 and the base wall 70. More specifically, the edge 90 is generally chamfered. The outer surface 70a of the base wall 70 includes a first wear ring 94 and a second wear ring 98. The first wear ring 94 and the second wear ring 98 are generally circular and protrude from the base wall 70. The wear rings 94, 98 are concentrically positioned on the base wall 70 relative to the longitudinal axis 62. More specifically, the diameter of the first wear ring 94 is greater than the diameter of the second wear ring 98, so that the second wear ring 98 is positioned within the first wear ring 94. In some embodiments, the wear rings 94, 98 may include alternative shapes and sizes. For example, in some embodiments, at least one of the wear rings 94, 98 may include a rectangular shape. In such a case, the wear rings 94, 98 may cooperate with corresponding apertures and / or grooves in the winding tool. More specifically, the cord winding tool may include a rectangular recess shaped and sized to receive at least one of the rectangular wear rings 94, 98. To rotate the housing 14 (e.g., to wind the cord through the trimmer head 10), the user aligns the cord winding tool adjacent the base wall 70 so that the wear rings 94, 98 are positioned within the recess. The user then manually rotates the tool relative to the trimmer head 10. Thus, because the wear rings 94, 98 engage the recess, the housing 14 rotates relative to the top plate 34 in a direction opposite to the feed direction, thereby winding the cord through the trimmer head 10 and onto the spool 18.

[0029] The outer surface 70a of the base wall 70 also includes ribs 102 that protrude from the body 30. The ribs 102 are positioned between the first wear ring 94 and the second wear ring 98 and are equally spaced about the base wall 70 about the longitudinal axis 62. In the illustrated embodiment, the body 30 includes four ribs 102. However, in alternative embodiments, the body 30 may include fewer ribs or additional ribs. When the trimmer head 10 strikes a working surface, the wear rings 94, 98 and the chamfered edge 90 prevent damage to the housing 14 of the trimmer head 10 regardless of the angle at which the base wall 70 is oriented relative to the working surface.

[0030] refer to Figure 3 to Figure 4 , the retainer 46 includes a ring 106 defining a central opening 110. The retainer 42 includes a first series of teeth 114 positioned on an upper surface of the ring 106 and a second series of teeth 118 positioned on a lower surface of the ring 106. The first series of teeth 114 are engageable with the teeth 60 positioned on the top plate 34 of the housing 14. Extending from the ring 106 are flexible retainer arms 122, each having a retainer member 126 engageable in an associated retainer opening 78 to connect the body 30 to the retainer 42.

[0031] refer to Figure 3 to Figure 4The spool 18 includes a generally cylindrical central body 130 including a throughbore extending through the spool 18 along an axis 136 generally co-linear with the longitudinal axis 62. An aperture 138 extends through the central body 130 to receive the wire such that the aperture 138 extends along an axis 140 substantially perpendicular to the longitudinal axis 62.

[0032] The through hole is shaped and sized to receive the nut 26. The nut 26 is positioned within the through hole and includes a threaded opening 144 that is shaped and sized to receive the shaft 5 of the string trimmer 1. To couple the trimmer head 10 to the shaft 5, the nut 26 is tightened around the drive shaft 5. The distal end 26a ( Figure 3 ) protrudes through the spool 18 and is received within the central boss 82 of the body 30 of the housing 14. The nut 26 also includes an aperture 148 extending through the nut 26 along an axis that is generally perpendicular to the longitudinal axis 62. Specifically, the aperture 148 of the nut 26 is aligned with the aperture 138 of the spool 18, thereby forming a passage for the wire to be fed through the housing 14, the spool 18, and the nut 26.

[0033] The central body 130 of the spool 18 includes a first upper flange 152 and a second lower flange 156. The first flange 152 and the second flange 156 are arranged in parallel planes. In some embodiments, the spool 18 may include additional flanges. Teeth 160 are formed on the upper flange 152 and are selectively engageable with the second series of teeth 118 on the retainer 42.

[0034] As described above, a spring is located at the lower end of the spool 18 to bias against the housing 14. In the biased position, the retainer 42 and the housing 14 are biased downward by the spring, and the spool 18 is drivingly connected to the housing 14 via the second series of teeth 118 located on the lower surface of the retainer 42 cooperating with the teeth 160 on the upper flange 152 of the spool 18.

[0035] refer to FIG. 6A to FIG. 6B, each eyelet 22 includes a body 162 received in a pocket of the body 30 and includes an ear 166 that limits movement into the pocket. A channel 170 is defined through each eyelet 22. An inner portion 174 of the channel 170 has a first shape (e.g., an oval shape as shown) having a length generally along the axis A greater than its width. The channel 170 transitions to an outer portion having a second shape (e.g., a circular shape) disposed in a protrusion 178 (e.g., a cylindrical protrusion) received in the eyelet opening 74 of the body 30. In other embodiments, the inner portion 174 of the channel 170 has an alternative shape of similar dimensions (e.g., having a length generally along the axis A greater than its width, such as a rectangular shape). Similarly, the outer portion disposed in the protrusion 178 can have an alternative shape such that at least its length generally along the axis A (and possibly its width) is less than the length (and possibly the width) of the channel 170.

[0036] To assemble the trimmer head 10, the central body 130 of the spool 18 is coupled to the retainer 42. Specifically, the retainer 42 is captured between the top plate 34 and the spool 18. The eyelet 22 is received in the eyelet pocket with each outer projection 178 extending through the eyelet opening 74. The retainer 42 is then snap-fitted to the body 30 with the retainer arms 122 biasing each retainer member 126 into the retainer opening 78. Thus, the spool 18 is captured between the body 30 and the retainer 46, and the trimmer head 10 is assembled as a unit.

[0037] To install the wire, the end of a single wire is fed through the passage in one eyelet 22 into and through the aperture 138 of the spool 18 and the aperture 148 of the nut 26. The end of the wire is then fed through the passage in the other eyelet 22 so that an equal amount of wire extends from each eyelet 22. The wire is centered and then wound onto the spool 18 (e.g., by rotating the housing 14 in a direction opposite to the feeding direction while holding the top plate 34) until sufficient wire extends from each eyelet 22.

[0038] In operation, the trimmer 1 is operated to rotate the drive shaft 5, thereby rotating the spool 18. As described above, in the biased initial position, the housing 14 and the retainer 42 are biased downwardly via the bias spring, and the spool 18 is drivingly connected to the housing 14 via a plurality of cooperating teeth 118, 160 located on the top ends of the retainer 42 and the spool 18. Therefore, the trimmer 1 can be operated to rotate the drive shaft 5, thereby rotating the spool 18 (together with the housing 14 and the retainer 42) and the cutting line so that the line can cut vegetation.

[0039] While the trimmer head 10 is being operated, the head 10 may "bump" the work surface, for example to dispense additional cutting line.

[0040] The housing 14 and the retainer 42 move axially on the insert-molded nut 18 against the spring bias to disengage the mating abutments (e.g., teeth 160, 118) on the top of the spool 18 and the bottom of the retainer 42. With these mating abutments 160, 118 disengaged, the housing 14 is free to rotate relative to the spool 18 to dispense additional line. The housing 14 can be pressed until the retainer 42 engages the top plate 34. At this point, a plurality of mating abutments (e.g., ramps or teeth 114 formed on the bottom of the top plate 34 and ramps or teeth 60 formed on the top of the retainer 42) engage each other to temporarily drive-connect the housing 14 to the spool 18. Once the housing 14 disengages from the surface, the spring biases the housing 14 and the retainer 42 downward to a biased position. When the mating abutments 114, 60 on the bottom of the top plate 34 and the top of the retainer 42 are disengaged, the housing 14 is again free to rotate relative to the spool 18 to dispense additional line until the mating abutments 160, 118 on the top of the spool 18 and the bottom of the retainer 42 engage in a biased position. Because the wear rings 94, 98 are positioned on the bottom of the base wall 70 of the body 30, the wear rings 94, 98 contact the working surface instead of the base wall 70. Thus, the housing 14 is protected from ground wear.

[0041] Although aspects of the invention have been described in detail with reference to certain preferred configurations, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention described.

Claims

1. A trimmer head for use with a string trimmer including a drive shaft, the trimmer head comprising: a housing rotatable about a rotation axis, the housing comprising a body defining a cavity, and a cover removably coupled to the body; a spool supported in the cavity and operable to support the wire to be dispensed; a retainer positioned between the housing and the spool; and A nut is positioned within the spool and is configured to be drivingly coupled to the drive shaft.

2. A trimmer head as claimed in claim 1, wherein: The nut is insert molded into the spool.

3. The trimmer head according to claim 1, wherein: The cover is keyed to the nut.

4. A trimmer head as claimed in claim 3, wherein: The spool is rotatably and axially fixed to the cover via the nut.

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

6. 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 passage for line to be fed through the trimmer head.

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

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

9. A string trimmer comprising: axis; a handle positioned on the shaft and including a grip that can be grasped by a user; a motor housing positioned on the shaft; a motor positioned within the motor housing and defining a drive shaft; as well as A trimmer head removably coupled to the drive shaft, the trimmer head comprising a housing defining a cavity and rotatable about an axis of rotation, a spool supported in the cavity and operable to support the wire to be dispensed, and A nut is insert molded into the spool and drivingly coupled to the drive shaft.

10. The string trimmer of claim 9, wherein: The trimmer head includes a retainer positioned between the housing and the spool.

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

12. The string trimmer of claim 9, wherein: The housing includes a body defining the cavity, and a cover removably coupled to the body.

13. The string trimmer of claim 12, wherein: The cover is keyed to the nut, and wherein the spool is rotatably and axially fixed to the cover via the nut.

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

15. 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 passage for line to be fed through the trimmer head.

16. A trimmer head for use with a string trimmer including a drive shaft, the trimmer head comprising: A housing capable of rotating about a rotation axis, the housing comprising a body defining a cavity, and a cover 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 the wire to be dispensed, wherein the spool is drivingly coupled to the drive shaft, wherein the spool comprises a central portion extending along the axis, a first flange proximate an end of the central portion and comprising a second plurality of teeth, and a second flange proximate an opposite end of the central portion; and A retainer is positioned between the housing and the spool, the retainer including a first surface having a third plurality of teeth configured to engage the first plurality of teeth and a second surface having a fourth plurality of teeth configured to engage the second plurality of teeth.

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

18. The trimmer head of claim 16, further comprising a biasing member supported in the cavity and positioned adjacent the second flange of the spool, wherein The biasing member is configured to bias the spool into engagement with the retainer.

19. A trimmer head as claimed in claim 18, wherein: When the spool is biased into engagement with the retainer, the second plurality of teeth on the spool engages a fourth plurality of teeth on the retainer.

20. The trimmer head of claim 18, wherein: When the spool is biased out of engagement with the retainer, the first plurality of teeth on the cover engage the third plurality of teeth on the retainer.

Images