Patent Description:
Landscape trimmers are typically useful for cutting grass or weeds, and may be used for edging around trees, fences, landscape borders, etc. Conventional landscape trimmers are often referred to as string trimmers and include an elongated shaft with a rotating head attached to one end of the elongated shaft. A spool or segment of monofilament string is often fixed to the rotating head in such embodiments. Thus, the monofilament string may rotate with the rotating head and act as cutting element. Recently, trimmers having solid, non-string cutting elements (e.g., blades) attached to the rotating head have been utilized.

There can be various shortcomings for existing trimmers. For instance, when selecting or buying a trimmer, a user is often forced to decide whether string cutting elements or solid blades are preferred. If a user later wishes to use a different cutting element, that user must often purchase a completely new rotating head or landscape trimmer. Moreover, regardless of what type of cutting element is chosen, the cutting elements will eventually need to be replaced. This typically requires significant disassembly of the rotating head. For instance, at least a portion of the rotating head must be removed from the elongated shaft before cutting elements can be replaced and the rotating head is returned to the elongated shaft. These can all be cumbersome sources of frustration for users. A trimmer head according to the preamble of claim <NUM> is known from <CIT>.

As a result, further improvements would be desirable in the field of landscape trimmers. In particular, it would useful for a rotating head to permit a user to selectively or alternately utilize a string or blade cutting element. Additionally or alternatively, it would be advantageous for rotating head to permit a cutting element to be selectively replaced without requiring significant disassembly or removal of the rotating head from an elongated shaft or body of a landscape trimmer.

A trimmer head according to the present invention is defined in independent claim <NUM>.

In accordance with the invention, a trimmer head for a trimmer is provided. The trimmer head includes a base plate defining an axial direction, a first snap surface, a second snap surface, a pivot head, and a blade retainer. The first snap surface extends from the base plate. The second snap surface extends from the base plate and is circumferentially spaced apart from the first snap surface. The pivot head is attached to the base plate. The pivot head includes an extended post having a blade support surface to selectively receive a flail blade. The blade retainer includes a radial arm, and a resilient detent. The radial arm is rotatably mounted to the base plate to rotate relative to the base plate between a first position at which the radial arm is circumferentially aligned with the pivot head and a second position at which the radial arm is circumferentially spaced apart from the pivot head. The resilient detent is held in a frictional-fit lock against the first snap surface in the first position and against the second snap surface in the second position.

As used herein, the term "or" is generally intended to be inclusive (i.e., "A or B" is intended to mean "A or B or both"). The terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

Turning now to the figures, <FIG> provide various views illustrating a trimmer head <NUM> for a landscape trimmer <NUM>, according to exemplary embodiments of the present disclosure.

In certain embodiments, the landscape trimmer <NUM> is a hand-held powered landscape trimmer <NUM> that include an elongated shaft <NUM> for supporting a handle with a grip (not pictured), as generally shown in <FIG>. However, these embodiments are merely provided for illustrative purposes, and are not intended to limit the present disclosure to any particular landscape trimmer. Thus, it is understood that in alternative embodiments, another suitable type of powered trimmer may be provided and, for example, may include a frame and wheels for movement over the ground.

Generally, the trimmer <NUM> includes an output shaft mechanically engaged with a motor <NUM> (e.g., a two-cycle gas engine, an electric motor, etc.) for driving rotation of the trimmer head <NUM>. As shown, the trimmer head <NUM> defines an axial direction A (e.g., at a base plate <NUM> thereof), as well as radial direction R perpendicular to the axial direction A and a circumferential direction C about the axial direction A. An assembly cap <NUM> is generally couplable to and rotatable with the output shaft of the motor <NUM>. As will described in greater detail below, a base plate <NUM> of the trimmer head <NUM> is selectively attached to the assembly cap <NUM> to rotate therewith. One or more flail blades <NUM> or trimmer lines (e.g., folded trimmer line <NUM>) may be provided on the base plate <NUM> to rotate with the trimmer head <NUM> and act as a cutting agent (e.g., for grass, shrubs, vegetation, etc.).

As shown, one or more pivot heads <NUM> may be attached (e.g., selectively attached) to the base plate <NUM>. When attached, the pivot heads <NUM> are rotationally fixed to the base plate <NUM> and may thus rotate with the base plate <NUM>. In other words, the pivot heads <NUM> may be rotated together about the axial direction A. Nonetheless, in some such embodiments, each pivot head <NUM> is generally permitted to pivot on the base plate <NUM> about its own corresponding pivot axis P (e.g., parallel to the axial direction A). Centrifugal force on the corresponding cutting agent (e.g., flail blade <NUM> or trimmer line <NUM>) by the pivot head <NUM> tends to extend the cutting agent outward (e.g., in the radial direction R), thus establishing frictional contact between the cutting agent and the extended post <NUM>. Tangential force imparted to the cutting agent during a cutting action may then pivot both the cutting agent and the pivot head <NUM>. When a trimmer line <NUM> is provided as a cutting agent, pivoting of the pivot head <NUM> and trimmer line <NUM> about the pivot axis P may advantageously mitigate the effects of vibrations or hard impacts.

Each pivot head <NUM> includes a corresponding extended post <NUM> to hold or support a flail blade <NUM> thereon. When assembled, the extended post <NUM> may be held above (e.g., spaced apart) from the base plate <NUM> and extend axially (e.g., along the corresponding pivot axis P or parallel to the axial direction A). The corresponding flail blade <NUM> may define an aperture through which the extended post <NUM> is permitted. Thus, the extended post <NUM> may include a blade support surface <NUM> (e.g., defined about the corresponding pivot axis P of the pivot head <NUM>) that can receive or generally hold the flail blade <NUM> thereon. In some such embodiments, the axial height or thickness of at least a portion of the flail blade <NUM> may be less than the axial height of the extended post <NUM>. At least a portion of the extended post <NUM>, such as an upper support surface <NUM>, may be positioned above the flail blade <NUM> (e.g., directly above the blade support surface <NUM>) as the flail blade <NUM> is received upon the blade support surface <NUM>.

In certain embodiments, each pivot head <NUM> includes a main body <NUM> from which the extended post <NUM> is projected. For instance, the extended post <NUM> may project from the main body <NUM> to a free end at which no additional or enlarged features are permanently affixed. When assembled, the main body <NUM> may rest on or be held above the base plate <NUM>. In turn, the main body <NUM> may be positioned between the extended post <NUM> and the base plate <NUM> (e.g., along the corresponding pivot axis P or relative to the axial direction A).

In exemplary embodiments, the main body <NUM> defines a string slot <NUM> that can receive a string trimmer line <NUM> therethrough. For instance, the string slot <NUM> may be defined as one or more openings through which two halves of a folded trimmer line <NUM> may be inserted or received. In optional embodiments, the string slot <NUM> is defined by a wall and projection <NUM> cooperating to define a pair of line receptacles (e.g., with an intermediate passage therebetween). The projection <NUM> separates the receptacles, and the intermediate passage thus communicates with the receptacles through respective channels. Thus, a continuous opening may be defined between the receptacles through the intermediate passage and the channels, as illustrated in <FIG>.

In additional or alternative embodiments, the pivot head <NUM> includes a head support <NUM> that is received (e.g., selectively received) within a complementary support void <NUM> defined by and within the base plate <NUM>. Optionally, the support void <NUM> may be formed from a support boss <NUM> extending axially upward (e.g., upward relative to the axial direction A) from a top surface <NUM> of base plate <NUM>. As shown, the head support <NUM> extends (e.g., from the main body <NUM>) in an opposite direction from the extended post <NUM>. When assembled, the head support <NUM> may thus be positioned opposite from the extended post <NUM> (e.g., relative to the axial direction A). In some such embodiments, the head support <NUM> may act to retain the pivot head <NUM> on the base plate <NUM>. For instance, the head support <NUM> may include one or more flexible clips or fingers <NUM> biased outwardly (e.g., radially outward from the corresponding pivot axis P) to releasably engage a bottom surface <NUM> of the base plate <NUM>, and flexible inwardly (e.g., radially inward toward the pivot axis P) to allow the head support <NUM> to move into and out of the support void <NUM>. Alternatively, the head support <NUM> may include a different structure to releasably retain or permanently retain the pivot head <NUM> relative to the base plate <NUM>.

In some embodiments, multiple pivot heads <NUM> are provided at discrete circumferential locations on the base plate <NUM>. Thus, each pivot head <NUM> may be circumferentially spaced about the axial direction A. In the illustrated embodiments, two pivot heads <NUM> are shown at two discrete circumferential locations on the base plate <NUM>. The two pivot heads <NUM> may be circumferentially spaced apart from each other more than <NUM>° about the axial direction A (e.g., along the circumferential direction C). In specific embodiments, the pivot heads <NUM> are spaced <NUM>° apart from each other along the circumferential direction C. However, it is understood that alternative embodiments may include any suitable number or arrangement of pivot heads <NUM> on the base plate <NUM> in one or more circumferential locations.

Along with one or more pivot heads <NUM>, a blade retainer <NUM> is provided on the base plate <NUM> to selectively pivot or rotate about the axial direction A. Specifically, the blade retainer <NUM> may not only rotate together or in tandem with the base plate <NUM> (e.g., during trimming operations), the blade retainer <NUM> may also rotate about the axial direction A relative to the base plate <NUM>. In certain embodiments, when assembled, the blade retainer <NUM> is rotatably mounted to the base plate <NUM> to rotate relative to the base plate <NUM> between at least a first position (e.g., <FIG> and <FIG>) and a second position (e.g., <FIG>).

As shown, the blade retainer <NUM> includes at least one radial arm <NUM> to selectively engage with a corresponding pivot head <NUM>. For instance, each pivot head <NUM> may correspond to a discrete radial arm <NUM> of the blade retainer <NUM>. Generally, the radial arm <NUM> extends along the radial direction R between a proximal end <NUM> and a distal end <NUM>. When assembled, the proximal end <NUM> is positioned radially inward (e.g., radially inward relative to the axial direction A) from the pivot head <NUM> while the distal end <NUM> is positioned to, or radially outward from, the radial location of the pivot head <NUM>. The proximal end <NUM> or distal end <NUM> may be positioned in a common plane (e.g., radial plane) with at least a portion of the extended post <NUM> (e.g., the upper support surface <NUM>), and may thus selectively engage (e.g., contact directly or indirectly) the extended post <NUM>. Nonetheless, another portion of the extended post <NUM> (e.g., the blade support surface <NUM> or main body <NUM>) may be positioned beneath the radial arm <NUM> (e.g., along the corresponding pivot axis P or relative to the axial direction A). For instance, the blade support surface <NUM> may be positioned between the distal end <NUM> of the blade retainer <NUM> and the base plate <NUM> relative to the axial direction A.

In moving between the first position and the second position, the radial arm <NUM> of the blade retainer <NUM> may be moved into and out of alignment with the extended post <NUM>. In the first position, the radial arm <NUM> may be circumferentially aligned with the pivot head <NUM>. For instance, the distal end <NUM> of the radial arm <NUM> may be positioned at a common circumferential location with the extended post <NUM>. The radial arm <NUM> may engage extended post <NUM> (e.g., at the upper support surface <NUM>). Moreover, at least a portion of the radial arm <NUM> may bound at least a portion of the extended post <NUM>. For instance, the radial arm <NUM> may block or cover a portion of the extended post (e.g., the blade support surface <NUM>) along the corresponding pivot axis P. Optionally, the radial arm <NUM> may define a circumferential channel <NUM> (e.g., C-shaped channel) having a single opening through which the extended post <NUM> may be selectively received (e.g., in the first position). The blade support surface <NUM> (and any flail blade <NUM> received thereon) may be held between the radial arm <NUM> and, for instance, the main body <NUM> or base plate <NUM>. Thus, in the first position, the flail blade <NUM> may be axially retained, or otherwise held, on the pivot head <NUM>.

In contrast to the first position, the radial arm <NUM> may be circumferentially spaced apart from the pivot head <NUM> is the second position. For instance, the distal end <NUM> of the radial arm <NUM> may be positioned at a separate or discrete circumferential location from the circumferential location of the pivot head <NUM>. In this second position, the radial arm <NUM> may be disengaged from the extended post <NUM> such that the extended post <NUM> (or any flail blade <NUM> thereon) is unimpeded and no longer blocked by the radial arm <NUM>. Thus, in the second position, the flail blade <NUM> may be freely moved onto or off of the pivot head <NUM>.

In some embodiments, the blade retainer <NUM> includes one or more intermediate members mechanically linking or attaching radial arm <NUM> (or radial arms <NUM>) to the base plate <NUM>. For instance, an axial arm <NUM> may extend axially downward (e.g., downward relative to the axial direction A) from (e.g., directly from) the radial arm <NUM>. In certain embodiments, the axial arm <NUM> extends axially downward from (e.g., directly from) an upper end <NUM> located at the proximal end <NUM> of the radial arm <NUM> (e.g., above the blade support surface <NUM> or main body <NUM>) to a lower end <NUM>. The radial arm <NUM> may extend radially (e.g., radially outward) from the upper end <NUM> of the axial arm <NUM>. When assembled, the lower end <NUM> may be positioned lower than the blade support surface <NUM> (e.g., relative to the axial direction A) and, for instance, at a top surface <NUM> of the base plate <NUM>.

A mounting plate or arm <NUM> may extend radially inward (e.g., toward the axial direction A) from (e.g., directly from) the lower end <NUM> of the axial arm <NUM> (e.g., at a location or plane that is below the blade support surface <NUM> or main body <NUM>). Additionally or alternatively, the mounting arm <NUM> may extend from the lower end <NUM> of the axial arm <NUM> to a mounting pin <NUM> rotatably securing the blade retainer <NUM> to the base plate <NUM>. One or more guide walls <NUM> may define an enlarged radial groove through which the mounting arm <NUM> may radially extend. For instance, the guide walls <NUM> may extend axially (e.g., upward along the corresponding pivot axis P or relative to the axial direction A) from the base plate <NUM>. As shown, the guide walls <NUM> may generally bound the mounting arm <NUM> along the circumferential direction C while permitting rotation between the first position and the second position. In some such embodiments, the guide walls <NUM> define, at least in part, the first position or the second position while preventing excess rotation of the blade retainer <NUM> (e.g., relative to the base plate <NUM>).

One or more lock assemblies <NUM> may be included to selectively hold the blade retainer <NUM> in the first position or the second position. As an example, a lock assembly <NUM> may include one or more resilient detents <NUM> to selectively engage one or more snap surfaces <NUM>, <NUM>. Specifically, the resilient detent <NUM> may be formed on a portion of the blade retainer <NUM> (e.g., the axial arm <NUM>) while the one or more snap surfaces <NUM>, <NUM> extend from a portion of the base plate <NUM> (e.g., at or on the support boss <NUM>). In exemplary embodiments, the resilient detent <NUM> is held in a frictional-fit lock against first snap surface <NUM> (e.g., on one circumferential side of the support boss <NUM>) in the first position, as illustrated in <FIG>. In additional or alternative embodiments, the resilient detent <NUM> is held in a frictional-fit lock against a second snap surface <NUM> (e.g., on an opposite circumferential side of the support boss <NUM>) in the second position, as illustrated in <FIG>. Thus, the blade retainer <NUM> may be prevented from inadvertently moving out of the first position (e.g., during trimming operations) or the second position (e.g., when removing or replacing the flail blade <NUM> or pivot head <NUM> from the base plate <NUM>).

In both the first position and the second position, at least a portion of blade retainer <NUM> may be held between the assembly cap <NUM> and the base plate <NUM> (e.g., along the axial direction A). In some embodiments, the mounting arm <NUM> is sandwiched between a top surface <NUM> of the base plate <NUM> and a bottom edge of the assembly cap <NUM>. When assembled, one or more retention mechanisms (e.g., suitable mechanical fasteners) selectively join the base plate <NUM> to the assembly cap <NUM> and thereby hold the mounting arm <NUM> between the assembly cap <NUM> and the base plate <NUM>. For instance, the base plate <NUM> may include one or more flexible fingers or clips <NUM> biased outwardly (e.g., radially outward from the axial direction A) to releasably engage a corresponding groove or channel <NUM> of the assembly cap <NUM>, and flexible inwardly (e.g., radially inward toward the axial direction A) to allow the flexible clip <NUM> to move into and out of assembly cap <NUM>. Optionally, the one or more retention mechanisms (e.g., flexible clips <NUM>) may be positioned radially inward (e.g., inward along the radial direction R) from the radial arm <NUM>. Thus, the assembly cap <NUM> may be attached to the base plate <NUM> radially inward from the radial arm <NUM>. In additional or alternative embodiments, the axial arm <NUM> or the radial arm <NUM> of the blade retainer <NUM> is/are positioned radially outward from an outer wall of the assembly cap <NUM>, thereby permitting the radial arm <NUM> to rotate relative to the base plate <NUM> without interference from the assembly cap <NUM>.

Advantageously, embodiments of the present disclosure may permit the selective removal or attachment of a pivot head <NUM> or cutting agent (e.g., flail blade <NUM> or trimmer line <NUM>) without requiring separation of a base plate <NUM> from an assembly cap <NUM> or other portion of a landscape trimmer <NUM>. Additionally or alternatively, embodiments of the present disclosure may advantageously permit a user to selectively and non-exclusively utilize a flail blade <NUM> and trimmer line <NUM>.

Claim 1:
A trimmer head (<NUM>) for use with a trimmer (<NUM>), the trimmer head (<NUM>) comprising:
a base plate (<NUM>) defining an axial direction (A);
a first snap surface (<NUM>) extending from the base plate (<NUM>);
a second snap surface (<NUM>) extending from the base plate (<NUM>) and circumferentially spaced apart from the first snap surface (<NUM>);
a pivot head (<NUM>) attached to the base plate (<NUM>), the pivot head (<NUM>) comprising an extended post (<NUM>) having a blade support surface (<NUM>) to selectively receive a flail blade (<NUM>); and
a blade retainer (<NUM>) comprising:
a radial arm (<NUM>)
characterized in that the radial arm (<NUM>) is rotatably mounted to the base plate (<NUM>) to rotate relative to the base plate (<NUM>) between a first position at which the radial arm (<NUM>) is circumferentially aligned with the pivot head (<NUM>) and a second position at which the radial arm (<NUM>) is circumferentially spaced apart from the pivot head (<NUM>); and
in that the blade retainer (<NUM>) further comprises a resilient detent (<NUM>) held in a frictional-fit lock against the first snap surface (<NUM>) in the first position and against the second snap surface (<NUM>) in the second position.