Patent ID: 12213404

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIGS.1to16depict various aspects of a new grass and brush trimmer head device embodying the principles and concepts of an embodiment of the disclosure and generally designated by the reference numeral (36) are disclosed.

FIG.1is a top-right perspective view of an assembled trimmer head incorporating the inventive concept, comprising the grass trimmer head assembly (4) and the blade assembly (3).

FIG.2is a top-right perspective illustration of the blade assembly (3) comprising a metal rod of any cross-sectional shape, straight or twisted, here shown round and untwisted or straight (1) and a spherical attachment (2) at one end of it made of metal, ceramic or PTFE at the root (3) acting as the retainer of the blade to the grass trimmer head assembly (4).

FIG.3is a bottom-right perspective illustration of the grass trimmer head device (36) comprising the grass trimmer head cup (7), spring-loaded blade retainers (5), rivets (6) fastening the spring-loaded blade retainers (5) on the grass trimmer head cup (7), blade assemblies (3), and a retainer nut representing the trimming machine's original trim-head retaining nut.

FIG.4is a bottom-right perspective illustration of the grass trimmer head cup (7), the blade receptacle cavity or socket (9) comprising the machined spherical or conical cavities (31) on the internal annular wall of the grass trimmer head cup (7), the predominantly circular openings (32) of the machined spherical cavities on the outer wall of the grass trimmer head cup (7), and the machined cavities (33) on the outer wall of the grass trimmer head cup (7) that allow the metal rod blades to rotate at higher angles in the trailing and upward directions for a rotating trimmer head, and the metal rod blade assembly (3) being inserted from the inside-out (37) in the grass trimmer head cup (7).

FIG.5is a top-right exploded-view perspective illustration of the grass trimmer head assembly (4) and blade assembly (3). Here, the blade receptacle cavity (9), the spring-loaded blade retainers (5), rivets (6), and a retainer nut (8) are visible.

FIG.6is a bottom-right exploded-view perspective illustration of the grass trimmer head device (36) comprising the grass trimmer head cup (7) blade assemblies (3), the blade receptacle cavity (9), the spring-loaded blade retainers (5), rivets (6), and a retainer nut (8).

FIG.0.7is a top-right exploded-view perspective illustration of the grass trimmer head assembly (4) and blade assembly (3), the blade receptacle cavity (9), an alternative version of a single spring loaded retainer (45) instead of the two-set of retainers (5), and a retainer nut (8).

FIG.8shows this same embodiment in a bottom-right exploded-view perspective illustration.

FIG.9is a top-right perspective view of the lower part of a generic hand-held and controlled grass trimmer (10), with the grass trimmer's retainer nut (8) the grass trimmer's threaded shaft (35), and a top-right exploded-view perspective of the grass trimmer head assembly (4) and blade assembly (3) as they are positioned before assembling and fastening on the grass-trimmer (10), whileFIG.10shows this same device in an assembled condition. The counterclockwise direction (34) that is intended for this embodiment of the invention while in operation is shown.

FIG.11is a top-right perspective illustration of the grass trimmer head assembly (4) with one blade assembly (3) at several critical positions the blade assembly goes through during operation, with the unlimited rotational freedom in Axial Rotation/[+/−M(z)] (14), the greatest rotational deflection to the rear/[−M(y)] (11), the second greatest rotational deflection area up [−M(x)] (15), and the rotational deflections to the front/[+M(y)] (12) and down/[+M(x)] (13).

FIG.12is a front section view of two of many possible shapes of internal retainer cavity shapes, namely the spherical cavity shape (31) and the conical cavity shape (41).

FIG.13shows, in a top-right perspective view, two of many different shapes the retainer section of the spring-loaded retainer (5) can take, namely a cylindrical shape (39) or a conical shape (41), to correspond to the respective cavity shapes (31,41).

FIGS.14to16show top-right perspective views, with some of the possible manufacturing method results for the trimmer-head cup.FIG.14shows a machined or die-cast embodiment;FIG.15shows a die-punched embodiment (42); andFIG.16shows an injection molded head (43). In this last embodiment, the head (43) is provided with metallic or ceramic inserts (44) that include the blade receptacle cavity (9).

As best illustrated inFIGS.1through9, the rotating trimmer head device (36) generally comprises a grass trimmer head assembly (4) and a plurality of solid metal rod blade assemblies (3), where the grass trimmer head assembly (4) is configured for coupling to a conventional weed trimmer (10) in a conventional manner such that the weed trimmer rotates the trimmer head device (36).

Trimmer head assembly (4) comprises of a trimmer-head cup (7), and a plurality of metal or any other spring material, spring-loaded retainers (5), attached in a conventional manner to the inside annular wall of the trimmer-head cup (7).

The trimmer head cup (7), is machined or die-casted out of metal, a substantially stronger material than the plastic material normally used for string-trimmer heads, or is injection molded with metal or ceramic inserts that include the blade-receptacle cavities (9) so as to withstand the heat and higher stresses occurring during operation at the root spherical portion (2) of each blade rod assembly (3).

The trimmer head cup (7) is created with a plurality of blade-receptacle cavities or sockets (9) circumferentially arranged around the, and traversing the vertical annular wall of the, trimmer-head cup (7) from the inside to the outside. Blade-receptacle cavities (9) are arranged equidistantly around the annular wall of trimmer head cup (7), so as to keep the entire trimming device (36) balanced.

Each blade-receptacle cavity (9) comprises of three distinct features; namely a machined spherical or conical cavity (31)(41) forming a socket receptacle cavity for a ball-and-socket joint where the spherical portion (2) of the blade assembly (3) will be retained, a predominantly circular opening (32) on the outside annular wall of the trimmer-head cup (7) created by the protrusion of the blade-receptacle spherical cavity (31), protruding partially further radially out, than the outer diameter of the external annular vertical wall of the trimmer-head cup (7), and an asymmetric cavity (33) machined on the external annular wall of the trimmer-head cup (7) and on the trailing side of predominantly circular opening (32), such that metal rod blade (1) can have larger rotational deflection freedom towards the rear (11) and up (15), as defined inFIG.9.

The grass and brush trimming device (36) comprises an equivalent number of spring-loaded retainers (5) according to the number of retainer cavities (9) found on a particular embodiment of (36) of the disclosure, and each spring-loaded retainer (5) is positioned so as its mostly vertical cylindrical (39) or conical (40) retainer portion is aligned to the internal spherical receptacle cavity (31) of each blade-receptacle cavity (9), so as to spring radially inwards when the spherical portion (2) of blade assembly (3) presses against it, and allow the spherical portion (2) of blade assembly (3) to enter the cavity (31), and press against spherical portion (2) loosely, retaining the spherical portion (2) of blade assembly (3) in the retainer cavity (31).

Each spring-loaded retainer (5) is assembled on the trimmer-head cup (7) by fastening, gluing, spring loading or any other conventional manner, shown here assembled using a rivet (6) and comprises a spring portion (38) which is responsible for the spring loading action on the spherical portion (2) of blade assembly (3), and a cylindrical (39) or any other appropriate shape retainer portion (39)(40) that is the actual geometry coming in contact and restricting the free dislodgement of the spherical portion (2) of blade assembly (3) from the head assembly (4), unless acted upon by a moderate force radially inward and downward by the user on the spherical portion (2) of blade assembly (3) from the outer side of the annular wall of the grass trimmer head cup (7), so as blade assembly (3) be removed and replaced.

A metal rod blade assembly (3), comprises a solid metal rod of any cross-sectional shape (1), made of, but not limited to, a spring steel family material such as piano-wire A228, EN 10270-1, SWP-A, SWP-B or others, and a spherical attachment (2) at one end of the metal rod (1), forming the root or retained portion of blade assembly (3), and spherical attachment (2) is attached to the rod in a conventional manner such as press fitting, fastening, over-molding, or gluing, and spherical attachment (2) is made of, but not limited to, metal, ceramic or PTFE, and acting as the retainer of the blade to the grass trimmer head assembly (4), once metal rod blade assembly (3) is inserted in one of a plurality of blade-receptacle cavities (31) from the inside radially out (37), in a manner so as to be easily removed and replaced when needed.

Each of the blade-receptacle cavities (9) comprises among other features of a machined spherical or conical cavity (31)(41) on the inside vertical annular wall of the trimmer-head cup (7) which is spherical (31) or conical (41) in geometry, with a diameter slightly larger than the spherical portion (2) of the blade assembly (3), so as to accept the spherical portion (2) of the blade assembly (3) and form a universal ball-joint, and so as to allow the metal rod portion (1) of the blade assembly (3), to rotate freely, within boundaries, in the rotational degrees of freedom M(x) (13)(15) and M(y) (11)(12), while allowing unlimited angle rotation in the direction of M(z) (14), as it passes through the predominantly circular opening (32), from the inside of the trimmer-head cup (7), out (37).

Each of the blade-receptacle cavities (9) comprises among other features of an asymmetrical machined cavity (33) on the outside vertical annular wall of the trimmer-head cup (7) and on the trailing side of circular opening (32), so as to allow the metal rod portion (1) of the blade assembly (3), to rotate at higher rotational angles in the direction of −M(y) (11), with up to 115 degrees of deflection or more, and to allow the maximum deflection of 25 degrees or more in the −M(x) (15) direction of the metal rod portion (1) of the blade assembly (3), to continue at an −M(x) angle equal to 25 degrees as it traverses all 115 degrees of deflection in the −M(y) (11) direction.

Each blade-receptacle cavity (9) comprises a predominantly circular opening (32) on the outside annular wall of the trimmer-head cup (7) created by the protrusion of the blade-Receptacle spherical cavity (31) protruding partially further radially out than the outer diameter of the external vertical annular wall of the trimmer-head cup (7) among others, so as to allow the metal rod portion (1) of the blade assembly (3), to rotate at angles of up to 25 degrees in the direction of +M(y) (12), and +M(x) (13).

Trimmer head device (36) is installed on a grass or brush trimmer (10), in a conventional manner. The metal rod blade assemblies (3) are coupled to the blade-receptacle cavities (9) such that the metal rod portion (1) of the blade assemblies (3) extend from the trimmer head assembly (4) radially outwards and cut vegetation or other material as the trimmer head device (36) is rotated by the grass or brush trimmer (10).

With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of an embodiment enabled by the disclosure, to include variations in size, angles, materials, shapes, form, function and manner of operation, manufacturing method of each part or assembly, assembly and use, are deemed readily apparent and obvious to a person skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by an embodiment of the disclosure.

Therefore, the foregoing preferred embodiment is considered as illustrative only of the principles of the disclosure. Further, since numerous modifications and changes will readily occur by those skilled in the art, it is not desired to limit the disclosure to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of this disclosure. In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be only one of the elements.