Mowing head and spool for the mowing head

Abstract

The mowing head comprises a housing and a spool for winding a cutting line, insertable into the housing. The spool comprises a central body with an outer surface for winding the cutting line. The spool also comprises two flanges spaced from each other along the axis of the spool. A space for winding the cutting line is defined between the first flange, the second flange, and the outer surface of the central body. Two openings, angularly offset from each other around the axis of the spool, are arranged between the two flanges. The two openings are connected to each other through an inner space of the spool, surrounded by the cylindrical wall of the central body of the spool. The inner space defines a transverse passage for the cutting line.

Description

MOWING HEAD AND SPOOL FOR THE MOWING HEADDESCRIPTIONTECHNICAL FIELD

[0001] The present invention relates to the field of gardening equipment, at both amateur and professional level. More in particular, the invention relates to improvements to the mowing heads, and the components thereof, for grass trimmers or the like, using, as a cutting member, a line, for example made of plastic, for cutting vegetation.BACKGROUND ART

[0002] In the gardening sector, both at professional and amateur level, mowing heads are used to cut vegetation. The heads are applied to the rotary shaft of a grass trimmer that can be actuated by an endothermic or electric engine. The mowing heads have different members to cut vegetation. In many cases, the cutting member is a line made of polymeric material. A stock of cutting line is accumulated on a spool in the form of coils wound around a central body of the spool, preferably between two flanges of the spool. The two opposite ends of the cutting line protrude through suitable holes for the passage of the cutting line provided, for instance, in bushings, arranged on the perimeter wall of a housing inside which the spool is housed.

[0003] In use, the mowing head is quickly rotated around its rotation axis and the line portions protruding from the housing of the spool are tensioned due to the centrifugal force and act on the vegetation, cutting it.

[0004] The line portions protruding from the housing of the mowing head are subject to wear and breakage, so it is periodically necessary to supply new portions of cutting line from the inside of the mowing head, by rotating the spool relative to the housing inside which it is contained. Once the stock of cutting line inside the mowing head is finished, it is necessary to load a new cutting line into the mowing head. To this end, the mowing head is usually opened, wherein the spool housing is comprised of two separable portions. The spool is removed from the housing and coils of cutting line are wound around it, thus forming a new stock. The opposite ends of the cutting line protrude from the spool and are then guided through passage holes provided in thehousing perimeter wall, before closing the housing with the spool inside it. These operations are long-lasting and onerous.

[0005] Therefore, mowing heads have been provided, wherein the reload of the cutting line, i.e. the formation of a new stock inside the housing and around the spool, is done without opening the housing. A mowing head of this kind is described for example in US2017 / 0208739. This head is particularly advantageous and eliminates many of the limitations and drawbacks of the prior art heads.

[0006] However, it can be further improved, particularly with regard to the way of inserting and winding a stock of cutting line.SUMMARY

[0007] According to an aspect, a mowing head is disclosed, comprising a housing and a spool for winding a cutting line, insertable into the housing. The spool comprises a central body with a cylindrical wall. The cylindrical wall comprises an outer surface, coaxial with the axis of the spool and forming a winding surface for winding the cutting line. The spool also comprises two flanges spaced from each other along the axis of the spool. A space for winding the cutting line is defined between the first flange, the second flange, and the outer surface of the cylindrical wall of the central body. The cylindrical wall of the central body of the spool has, between the two flanges, two openings, angularly offset from each other around the axis of the spool. The two openings are connected to each other through an inner space of the spool, surrounded by the cylindrical wall of the central body of the spool. The inner space defines a transverse passage for the cutting line.

[0008] Further advantageous embodiments of the mowing head are described below with reference to the accompanying drawing, and are defined in the appended claims.BRIEF DESCRIPTION OF THE DRAWING

[0009] The invention will be better understood by following the description below and the attached drawing, showing a non-limiting embodiment of the invention. More specifically, in the drawing:Fig. 1 is an exploded view of an embodiment of a mowing head;Fig. 2 is a cut-away view of the exploded view of Fig. 1;Fig. 3 is a top axonometric view of the mounted mowing head;Fig. 4 is a plan view of Fig. 3;Figs. 5 and 6 are side views according to V-V and VI- VI of Fig. 4;Figs. 7 and 8 are cross-sections according to the lines VII- VII and VIII- VIII of Fig. 4;Fig. 9 is a bottom axonometric view of the winding spool of the mowing head of Figs. 1 to 7;Fig. 10 is a side view according to X-X of Figs. 12 and 13;Fig. 11 is a top axonometric view of the spool of Figs. 9 and 10;Fig. 12 is a view according to XII-XII of Figs. 10 and 13;Fig. 13 is a view according to XIII-XIII of Fig. 12;Fig. 14 is a view according to XIV-XIV of Figs. 10 and 13;Fig. 15 is a further axonometric view from the bottom of the spool of Figs. 9 to 14;Fig. 16 is a side view according to XVI-XVI of Fig. 13;Fig. 17 is a top axonometric view of the spool of Figs. 9 to 16;Fig. 18 is an exploded view of a further embodiment of a mowing head;Fig. 19 is a cut-away view of the exploded view of Fig. 18;Fig. 20 is a top view of the mowing head of Figs. 18 and 19, mounted;Fig. 21 is an axonometric view of the mowing head of Fig. 20;Figs. 22 and 23 are cross-sectional views according to XXII-XXII and XXIII- XXIII of Fig. 20;Fig. 24 is a view according to XXIV-XXIV of Fig. 25 of the spool of the mowing head of Figs. 18 to 23;Fig. 25 is a view according to XXV-XXV of Fig. 26;Fig. 26 is a side view according to XXVI-XXVI of Fig. 24;Figs. 27 and 28 are axonometric views, from the top and the bottom respectively, of the spool of Figs. 24 to 26;Fig. 29 is a cut-away exploded view of a further embodiment of a mowing head;Fig. 30 is a plan view of the mowing head of Fig. 29, mounted and with some parts removed;Figs. 31 and 32 are cross-sectional views according to XXXI-XXXI and to XXXII-XXXII of Fig. 30;Fig. 33 is an axonometric view of a portion of mowing head in a furtherembodiment;Fig. 34 is a cross-sectional view of the portion of mowing head of Fig. 33; and Figs. 35, 36, and 37 are two sectional axonometric views and a sectional view of the spool of the mowing head of Figs. 33 and 34.DETAILED DESCRIPTIONEmbodiment of Figs. 1 to 17

[0010] Figs. 1 to 17 show a first embodiment of a mowing head according to the invention; in particular, Figs. 9 to 17 show various views and cross-sections of the spool of the mowing head.

[0011] In this embodiment, the mowing head 1 comprises a housing 3, which in turn comprises a housing portion 3 A and a housing portion 3B. Here below, the housing portion 3 A will be conventionally referred to as "first portion" or "upper portion" of the housing 3, and the housing portion 3B will be conventionally referred to as "second portion" or "lower portion" of the housing 3. When the mowing head 1 is applied to a grass trimmer, the upper portion 3 A of the housing 3 faces the drive shaft of the grass trimmer.

[0012] The two housing portions 3A, 3B can be coupled with each other through mutual coupling and releasing devices. In some embodiments, the mutual coupling and releasing devices comprise elastic tabs and slots for engaging the elastic tabs. In the illustrated embodiment, the elastic tabs, indicated by the reference number 5, are integral with the first housing portion 3 A and enter slots 7 formed in the second housing portion 3B.

[0013] The first housing portion 3A forms an outer surface 3C of the housing 3, transverse or generally orthogonal to an axis A-A of rotation of the mowing head 1. Similarly, the second housing portion 3B forms an outer surface 3D of the housing 3, transverse or generally orthogonal to the axis A-A of rotation of the mowing head 1.

[0014] The housing 3 also comprises a perimeter wall 3E. In the illustrated embodiment, the perimeter wall 3E is formed by the first housing portion 3A, and portions of the perimeter wall 3E form the tabs 5.

[0015] Holes 3F for the passage of a cutting line are provided in the perimeter wall 3E. Preferably, two holes 3F are provided, that are diametrically opposite, i.e., offset by 180° relative to each other around the axis A-A of rotation of the mowing head 1.

[0016] In advantageous embodiments, the holes are provided with bushings 9 with holes 9F. Whilst the housing portions 3A, 3B are preferably made of polymeric material, the bushings 9 can be made of metal, or fiber- or powder-reinforced polymeric material, which increase the wear resistance. When the mowing head 1 has bushings 9, these bushings are holed (9F), so as to have passage holes for the cutting line.

[0017] A spool 11 is insertable in the housing formed by the first housing portion 3 A and the second housing portion 3B.

[0018] In Figs. 9 to 10, the spool 11 is shown alone, without the mowing head 1. In Figs. 9 to 10, the details of the spool 11 are shown, indicated by reference numbers.

[0019] The spool 11 comprises a central body 13 that in turn comprises a cylindrical wall with an outer cylindrical surface 13.1 and an inner surface 13.2. In advantageous embodiments, the outer surface 13.1 is cylindrical with circular cross-section and has a diameter D (see Fig. 7) of 100 mm or less, preferably 90 mm or less.

[0020] The spool 11 also comprises one or preferably two flanges, indicated in the attached drawing by the reference numbers 15 and 17. The flange 15 comprises a substantially flat outer surface 15.1 and a substantially flat inner surface 15.2. Similarly, the flange 17 comprises a substantially flat outer surface 17.1 and a substantially flat inner surface 17.2. Herein, the term “inner” refers to the surface of each flange facing the other flange, that is, the two opposite surfaces. When mounted, the outer surfaces 15.1, 17.1 face toward the housing portions 3 A, 3B and more exactly toward the walls of these housing portions that form the transverse surfaces 3C and 3D.

[0021] An annular space, or winding space, for winding the cutting line is defined between the outer cylindrical surface 13.1 of the central body 13 and the surfaces 15.2 and 17.2, forming in this way a stock of cutting line consisting of coils wound around the central body 13. Here below, the outer cylindrical surface is also referred to as“winding surface”.

[0022] In some embodiments, teeth 19 are provided on the outer surface 15.1 of the flange 15, and teeth 21 are formed on the outer surface 17.1 of the flange 17. The teeth 19 co-act with stops 23 provided on the housing portion 3 A, and more specifically on the surface of the housing portion 3 A facing the spool 11. The teeth 21 co-act with stops 25 provided on the housing portion 3B, and more specifically on the surface of the housing portion 3B facing the spool 11 when the spool is mounted in the mowing head 1. By means of a known mechanism, which will be briefly described below, the first set of teeth 19, the second set of teeth 21, and the stops 23, 25 enable the stepwise rotation of the spool 11 within the housing 3 when the mowing head 1 is in use and is rotating, through an alternating translation movement of the spool 11 in the direction of the axis A-A of rotation of the mowing head 1.

[0023] In some embodiments, the spool 11 comprises a shank 27 coaxial to the wall of the central body 13 of the spool 11, forming the outer cylindrical wall 13.1. The shank 27 is preferably hollow inside, so as to leave space for a coupling member for coupling the mowing head 1 to the drive shaft of the grass trimmer (not shown).

[0024] In some embodiments, the shank 27 has a proximal portion, adjacent to the flange 15, and a distal portion, extending beyond the flange 17. The proximal portion has an inner diameter equal to, or greater than, the inner diameter of the distal portion. The inner diameter of the proximal portion is indicated in Fig. 8 with the reference letter d. In some embodiments, the inner diameter d is 8 mm or more.

[0025] The shank 27 can have various shapes, for example, but not necessarily, cylindrical shape. In some embodiments, the shank 27 has a prismatic shape, or cylindrical with one or more flattened parts. In some embodiments, the shank 27 has an inner hole of non-circular shape so as to form a torsional coupling to a motion transmission member, connected to, or integral with, the drive shaft of the grass trimmer, not shown.

[0026] In some embodiments, the cylindrical wall of the central body of the spool 11, which forms the outer cylindrical winding surface, 13.1 and the inner surface 13.2, comprises a first through opening 31, or a first pair of through openings 31, and a second through opening 33, or a second pair of through openings 33, see especiallyFigs. 10, 13 and 16. The through openings or pairs of through openings 31, 33 are angularly offset around an axis B-B of the spool 11. When mounted, the axis B-B is coincident or approximately coincident with the axis A-A of the mowing head 1. The angular offset between the two opposite through openings, or pairs of through openings, 31, 33, is advantageously approximately equal to the angular offset of the holes 3F of the perimeter wall 3E and of the holes 9F of the bushings 9. In this way, when a new cutting line shall be loaded in the spool 11, the through openings 31, 33 and the holes 9F of the bushings 9 align. In the illustrated example, both the holes 9F and the through openings, or pair of through openings, 31, 33 are offset by 180°.

[0027] The through openings 31, 33 are formed along the cylindrical wall of the central body 13 in intermediate position between the flanges 15, 17, and specifically between a median plane of the first flange and a median plane of the second flange. The term “median plane” of the flange refers to a plane lying parallel to the flange and arranged between the two opposite faces of the flange. For example, the through openings 31, 33 are in equidistant position from the surfaces 15.2 and 17.2 of the flanges 15, 17.

[0028] The through openings 31, 33 are connected to each other through an inner space 35 of the spool 11 (see especially Figs. 9 and 12), delimited between the inner surface 13.2 of the cylindrical wall of the central body 13 and the side surface of the shank 27. The inner space 35 is also delimited by a closing wall, which, in this embodiment, consists of an annular wall 37 that can be part of the spool 11, i.e. can be made in a single piece with the cylindrical wall forming the surfaces 13.1 and 13.2. Furthermore, the inner space 35 is closed by a second closing wall, which can consist of a washer, parallel to the annular wall 37 and spaced from it in the direction of the axis B-B. Alternatively, as will be described in more detail below, the inner space 35 is closed, when the spool 11 is mounted in the housing 3, by a second closing annular wall formed by a component of the mowing head 1, described below.

[0029] In some embodiments, guide elements 36 are provided in the inner space 35, forming one or more guide channels 38 for the cutting line, the guide channels 38 extending around the shank 27 from one to the other of the opposite openings 31, 33. The guide elements 36 can be in the form of projections, protruding in the direction of the axis B-B from the surface of the annular wall 37 facing the inner space 35.

[0030] The inner space 35, with or without the guide elements 36, defines a transverse passage for the cutting line F that can pass through the spool 11 and be loaded from outside the mowing head 1 in the way described below, without the need to open the housing 3.

[0031] The mowing head 1 also comprises a control member 41 to control an axial movement of the spool 11 within the housing 3. In some embodiments, the control member comprises a knob 43, which can be made in a single piece with the shank 27, or (as illustrated) can consist of a separate component that is connected to the spool 11, and more specifically to the shank 27, for example by means of a screw 44 or the like.

[0032] In some embodiments, the control member 41 protrudes from the mowing head 1 beyond the outer surface of the second housing portion 3B, i.e., the housing portion that, when the mowing head 1 is mounted on the grass trimmer, is on the opposite side relative to the drive shaft of the grass trimmer.

[0033] In some embodiments, an elastic member 45 is associated with the control member 41. The elastic member 45 is for example a compression coil spring that, when mounted, surrounds the shank 27 of the spool 11 arranged in the housing 3. The elastic member 45 is compressed between the knob 43 and a stop that is axially fixed relative to the housing 3. The axially fixed stop can be formed directly as an integral part of one of the housing portions 3 A, 3B, and more precisely of that housing portion (in the illustrated example, the housing portion 3B) from which the knob 43 protrudes. In other embodiments, as shown here and better described below, the mowing head 1 comprises a winding member for manually winding the cutting line around the spool 11, through the rotation of the spool relative to the housing 3, when the mowing head 1 is mounted with the spool inside it. The manual winding member can form an axially fixed stop to hold the elastic member 45, as described below.

[0034] In the illustrated embodiment, the manual winding member comprises a rotary knob 51 that, when mounted, is coaxial with the shank 27 of the spool 11. The rotary knob 51 comprises an outer annular portion 51.1 that, when mounted, is positioned outside the housing 3. The outer annular portion 51.1 comprises a plurality of recesses 51.2 that facilitate grip by a user, for the purposes explained below.

[0035] The rotary knob 51 also has a configuration adapted to provide a torsional coupling to the spool 11, so that the rotation of the rotary knob 51 relative to the housing 3 around the axis A-A causes the rotation of the spool 11 within the housing 3.

[0036] In some embodiments, the rotary knob 51 comprises, for example, a bush 51.3, integral with the outer annular portion 51.1. When mounted, the bush 51.3 extends coaxially around the shank 27 of the spool 11. The shank 27 extends through a hole provided in the bush 51.3. At an opposite end with respect to the outer annular portion 51.1, the bush 51.3 has an annular collar 51.4 protruding radially inward, that is, toward the axis A-A of rotation of the mowing head 1.

[0037] In some embodiments, the annular collar 51.4 forms a stop for the elastic member 45, which is therefore held between the annular collar 51.4 and the knob 43. As a result, the rotary knob 51 is axially pushed toward the inside of the housing 3 by the elastic member 45, and the outer annular portion 51.1 is therefore pressed, by the spring force of the elastic member 45, against the outer surface of the housing portion (in the example, the second housing portion 3B), from which the control member 41 and the rotary knob 51 protrude.

[0038] Moreover, the elastic member 45 pushes the spool 11 to a rest position within the housing 3. This thrust is generated by the elastic member 45 that acts against the control member 41, stressing the spool 11 to rest against the inner surface of the second portion 3B of the housing 3. As it will be better explained below, by pushing the control member 41 toward the inside of the housing 3, for example, by pressing the mowing head 1, through the grass trimmer on which it is mounted, against the ground, the control member 41 causes a contraction of the elastic member 45 and therefore an axial movement of the spool 11 toward the opposite housing portion 3 A. This movement is indicated by the arrow fl 1 in Figs. 7 and 8.

[0039] The rotary knob 51 is angularly constrained to the spool 11 by means of a mechanical coupling. To this end, one or more projections (two in the illustrated example) are provided along the collar 51.4, indicated by the reference number 51.5 (Figs. 1, 2, 7), which co-act with notches or cavities 27.1 (Figs. 9 and 12) formed in the shank 27 of the spool 11. The angular coupling between the rotary knob 51 and thespool 11 can be realized also in other ways, for example by means of a non-circular cross-section of the inner hole of the collar 51.4 and a corresponding cross-section of the shank 27, to achieve a fit coupling between the shank 27 and the rotary knob 51.

[0040] With this mechanical coupling, the rotation of the rotary knob 51 around the axis A-A of the mowing head 1 causes a rotation of the spool 11 within the housing 3.

[0041] As shown in Figs. 5 to 8, when mounted, the knob 43 of the control member 41 protrudes axially from the outer surface of the portion 3B of the housing 3 beyond the thickness of the rotary knob 51, so that, when the mowing head 1 is pressed against the ground, for example, in order to lengthen the cutting line, the knob 43 presses against the ground and translates toward the housing 3, without the rotary knob 51 touching the ground.

[0042] The use of the mowing head 1 described above is as follows.

[0043] The cutting line (schematically indicated by the dashed line F in Fig. 8 and not shown in the other figures) can be loaded in the mowing head 1 as follows. The spool 11, housed in the closed mowing head 1, is rotated, through the rotary knob 51, until the openings 31, 33 are aligned with the holes 3F, or more precisely with the corresponding holes 9F provided in the bushings 9. Once this position has been achieved, the user can insert a first end of a piece of cutting line F through the mowing head 1 by passing it through the hole 9F of one of the bushings 9, through the opening 31 or 33, through the inner space 35, through the opposite opening 33 or 31, and finally through the hole 9F of the bushing 9 opposite to the entrance bushing. The piece of cutting line F can be inserted through the mowing head 1 until two portions thereof of approximately equal length protrude from the two bushings 9.

[0044] At this point, by means of the rotary knob 51, the user can wind the cutting line F around the spool 11 by turning the rotary knob 51, and consequently the spool 11, relative to the housing 3 of the mowing head 1. While being wound around the central body 13 of the spool 11, the cutting line F forms a series of stock coils (some of them shown in dashed line in Fig. 8) around the winding surface 13.1 of the spool central body 13, without the need to open the mowing head 1, which can remain for example attached to the grass trimmer (not shown).

[0045] Thanks to the fact that the openings 31, 33 are arranged in intermediate position between the flanges 15, 17 of the spool 11, the winding of the cutting line F is simplified compared to the prior art solutions. Furthermore, the coils are more easily arranged around the winding surface 13.1, and essentially it is possible easily to wind more cutting line than in the prior art mowing heads.

[0046] The winding of the stock of cutting line ends by leaving two pieces of cutting line protruding from the two bushings 9, so that, by rotating the mowing head 1 around the axis A-A of rotation, the portions of cutting line F protruding from the two bushings are lengthened and form members for cutting vegetation.

[0047] In practice, the openings 31, 33 and the inner space 35 of the spool 11 form constraining or anchoring member for anchoring the cutting line F to the spool 11.

[0048] The insertion of the cutting line F through the inner space 35 can be facilitated by means of the guides 38 formed by the projections or guide elements 36, if any.

[0049] In use, the cutting line F protruding from the bushings 9 of the mowing head 1 gets worn out and may break. To have again an adequate length of cutting line protruding from both the bushings 9, while the mowing head 1 is kept rotating around the axis A-A of rotation through the drive shaft of the grass trimmer (not shown), the user presses, once or repeatedly, the knob 45 of the mowing head 1 against the ground, causing a contraction of the elastic member 45 and an axial movement of the knob 45 toward the inside of the housing 3. This repeated movement alternately causes the teeth 21 to be released from the stops 25 and the teeth 19 to be constrained to the stops 23. As the teeth and / or stops are angularly offset, the axial movement of the spool 11 within the housing 3 causes the stepwise rotation thereof, under the thrust of the centrifugal force acting on the portions of cutting line protruding from the bushings 9, consequently stressing the spool 11 to rotate about its axis B-B relative to the housing 3 in the direction of unwinding of the cutting line F.

[0050] Every time the mowing head is pressed against the ground and subsequently released, the spool 11 angularly rotates by one step and consequently unwinds a portion of cutting line F that is pulled outside both bushings 9 under the effect of the centrifugal force.

[0051] The operation is repeated one or more times until to have again the desired length of cutting line portions protruding from the mowing head 1.

[0052] Thanks to the fact that the rotary knob 51 is arranged in backed position with respect to the knob 43, the operation described above for lengthening the cutting line does not cause the rotary knob 51 to touch, and to rub against, the ground. This reduces the wear of the rotary knob 51.

[0053] In the embodiment of Figs. 1 to 17, the second housing portion 3B comprises a bush 3H (Figs. 1, 2, 7, and 8), protruding toward the inside of the housing 3 and ending in a collar 3G. The rotary knob 51 is guided inside the bush 3H, and the collar 51.4 thereof rests against the collar 3G. The collar 3G closes the inner space 35 of the spool 11 when the latter is housed in the housing 3.

[0054] In other embodiments, the collar 3G is omitted, and the inner space 35 of the spool 11 is closed by the collar 51.4 of the rotary knob 51.

[0055] In the illustrated embodiment, the knob 43 for controlling the lengthening of the cutting line F, and the rotary knob 51 for manually rotating the spool 11 and winding the cutting line F around it, are provided on the side of the mowing head 1 opposite to the face that, in use, faces the grass trimmer. A reverse embodiment is also possible, as described below.Embodiment of Figs. 18 to 28

[0056] Figs. 18 to 28 show a different embodiment of the invention, where the knob 43 of the control member for lengthening the cutting line, and the rotary knob 51 for manually winding the cutting line, are provided on the opposite side of the mowing head 1, that is, on the side that interfaces with the drive shaft of the grass trimmer. Equal numbers indicate equal or equivalent parts to those described with reference to Figs. 1 to 17. Here below, the differences from what illustrated above will be mainly described, while the description of the parts substantially equal to those described above with reference to Figs. 1 to 17 will not be repeated.

[0057] In this embodiment, as the knob 43 is arranged on the side of the mowing head 1 that is connected to the drive shaft of the grass trimmer, the knob 43 of the control member 41 is centrally holed, to allow the passage of the drive shaft or of anintermediate mechanical element connecting the mowing head 1 to the drive shaft of the grass trimmer.

[0058] Moreover, in this embodiment it is not necessary for the knob 43 to protrude from the housing 3 of the mowing head 1 more than the rotary knob 51. In fact, when the knob 43 of the control member 41 protrudes from the upper part of the mowing head 1, that is, from the part facing the grass trimmer, the thrust for imparting the rotation of the spool 11 relative to the housing 3, where it is contained, due to the centrifugal force, is applied through an end portion of the grass trimmer against the knob 43 while the opposite part (housing portion 3B), with no protruding parts, rests on the ground. The part of the grass trimmer that presses against the knob 43 has a smaller diameter than the outside diameter of the rotary knob 51, and can therefore enter a cavity 51.10 of the rotary knob. The cavity 51.10 is surrounded by an annular edge 51.11, on the outer surface of which recesses 51.2 are formed that make it easier for a user to grip and to rotate the rotary knob 51, similar to the recesses 51.2 described above.

[0059] In advantageous embodiments, the cavity 51.10 has an inner diameter DI (see Fig. 22) of 40 mm or more. In this way, the end of the grass trimmer to which the mowing head is attached can protrude inside the cavity 51.10 and can be at least partially surrounded by the annular edge 51.11. The annular edge 51.11 advantageously has a height H (see Fig. 22) of 2 mm or more, preferably of 3 mm or more, more preferably of 5 mm or more, even more preferably comprised between 5 mm and 20 mm, or between 5 mm and 15 mm.

[0060] When the mowing head 1 is applied to the grass trimmer, the cavity 51.10 with the annular edge 51.11 protects the power take-off of the grass trimmer, preventing or reducing the risk of vegetation twisting around the drive shaft of the grass trimmer.

[0061] The spool 11 is mounted substantially reversely to what described with reference to the embodiment of Figs. 1 to 17, so that the flange 17 faces the first housing portion 3 A and the flange 15 faces the second housing portion 3B. The teeth 19 co-act with the stops 25 of the lower housing portion 3B, while the teeth 21 co-act with the stops 23 of the upper housing portion 3 A.

[0062] In some embodiments, the shank 27 has a distal end 27.10, with a female thread 27.11, adapted to engage a male thread of a drive shaft, thus forming a mechanical coupling for coupling to the grass trimmer. The distal end 27.10 forms a connecting member, i.e., a drive, for the connection to a drive shaft of the grass trimmer. In other embodiments, the distal end 27.10 and the female thread 27.11 can be realized as a separate element from the shank 27, attached to the shank 27 in a fixed manner, by gluing or co-molding, or removable manner. In other embodiments, the connecting member comprises a threaded pin, with a male thread instead of a female thread, to engage to a female thread provided in the drive shaft of the grass trimmer.

[0063] In advantageous embodiments, the rotary knob 51 has, inside the annular edge 51.11, an annular slot 51.15 opposite the opening of the cavity 51.10, shown in Figs. 18, 19, 22, and 23. The annular slot 51.15 engages an annular projection 3L that extends parallel to the axis A-A from the outer surface 3C of the first housing portion 3 A. This provides stabilization and guidance for the rotary knob 51 on the housing 3.Embodiment of Figs. 29 to 32

[0064] Figs. 29 to 32 show a variant of the embodiment of Figs. 1 to 17. Equal numbers indicate equal or equivalent parts to those described with reference to Figs. 1 to 17.

[0065] In this embodiment, the transverse passage for the cutting line F through the spool 11 is curved, and the bushings 9 for the passage of the cutting line F are inclined with respect to a radial direction, i.e., a direction orthogonal to the axis A-A of rotation of the mowing head 1.

[0066] More specifically, in this embodiment, the transverse passage for the cutting line F defines a curvature whose concavity faces downward, and the bushings 9 are directed in such a way that the portions of cutting line F protruding from the mowing head 1 are directed toward the bottom of the mowing head 1, i.e., toward the outer surface 3F of the housing portion 3B, opposite the side of the mowing head 1 interfacing with the grass trimmer.

[0067] In this way, the points at which the cutting line F exits the mowing head 1, defined by the bushings 9, are closer to the work surface, that is, to the ground alongwhich the mowing head 1 is moved during grass cutting. In this way, the grass can be cut shorter, despite the presence of the knob 43 and the rotary knob 51 protruding from the outer surface of the housing portion 3B.Embodiment of Figs. 33 to 37

[0068] A curved transverse passage for the cutting line F can also be provided in a variant of the embodiment of Figs. 18 to 28. Figs. 33 to 37 show portions of the cutting head 1 and details of the spool 11 in this embodiment. Equal numbers indicate equal or equivalent parts to that described with reference to the previous figures.

[0069] In the embodiments described above, two innovations have been disclosed with respect to the prior art mowing heads, that can be both provided in combination, as shown in the figures, or used independently of each other.

[0070] More specifically, the above description discloses an innovative configuration of the anchoring members for anchoring the cutting line F to the mowing head 1 and more specifically to the spool 11. In this embodiment, the anchoring members consist of the openings 31, 33 and the inner space 35, the arrangement of which, as mentioned above, allows easier smoother insertion and better winding of the cutting line, with a possible increase in the amount of cutting line accumulated around the spool 11.

[0071] The above description discloses embodiments where two distinct elements are used to lengthen the cutting line and to manually wind it around the spool, and more specifically the control member 41 and the rotary knob 51, that are coaxial to, and axially offset from, each other. This advantageously allows to mount the rotary knob 51 in backed position, i.e. protruding from the outer surface of the mowing head less than the knob 43. This position protects the rotary knob 51 against wear. Furthermore, the diameter of the rotary knob 51 can be larger than the diameter of the knob 43, making it easier to grip and turn it.

[0072] However, it should be understood that, in other embodiments, the rotary knob 51 can be omitted and the knob 43 can be used also as a member to control the rotation of the spool 11 within the housing 3. In this case, the elastic member 45 rests on an annular stop formed by the housing portion. However, there is still the advantage ofan improved winding of the cutting line around the spool 11.

[0073] In further embodiments, a different mechanism for lengthening the cutting line may be provided.

Claims

CLAIMS1. A mowing head (1) comprising:- a housing (3);- a spool (11) for winding a cutting line (F), insertable into the housing (3) and comprising: o a central body (13) having a cylindrical wall, coaxial with an axis (B-B) of the spool (11); wherein the cylindrical wall comprises an outer surface (13.1), coaxial with the axis (B-B) of the spool (11) and forming a winding surface for winding the cutting line (F); o a first flange (15) and a second flange (17), spaced from each other along the axis (B-B) of the spool (11); wherein an annular space for winding the cutting line (F) is defined between the first flange (15), the second flange (17), and the outer surface (13.1) of the cylindrical wall of the central body (13), forming in this way a stock consisting of coils wound around the outer surface (13.1) of the central body (13); wherein: the cylindrical wall of the central body (13) of the spool (11) has, between the first flange (15) and the second flange (17), a first opening (31) and a second opening (33) angularly offset from each other around the axis (B-B) of the spool (11); the first opening (31) and the second opening (33) are connected to each other through an inner space (35) of the spool (11) surrounded by the cylindrical wall of the central body (13) of the spool (11); the inner space (35) defines a transverse passage for the cutting line (F), wherein the spool (11) comprises a shank (27) coaxial with the central body (13) of the spool (11); and the transverse passage for the cutting line (F) extends around the shank (27), between the shank (27) and the cylindrical wall of the central body (13) of the spool (11).

2. The mowing head of claim 1, wherein the housing (3) comprises a perimeter wall (3E) extending around an axis (A-A) of rotation of the mowing head (1); and wherein at least two holes (3F) are provided in the perimeter wall (3E) of the housing (3) for the passage of a cutting line (F), wherein the two holes are angularly offset from each other around the axis (A-A) of rotation.

3. The mowing head (1) of claim 2, wherein the housing (3) comprises a first housing portion (3A) and a second housing portion (3B); wherein the firsthousing portion (3 A) and the second housing portion (3B) comprise devices (5, 7) for mutual coupling and releasing; and wherein the perimeter wall (3E) of the housing (3) is integral with one of the first housing portion (3 A) and second housing portion (3B).

4. The mowing head (1) of any one of the preceding claims, comprising an elastic member (45) that stresses the spool (11) to a rest position, and a control member (41) adapted to control an axial movement of the spool (11) within the housing (3) against an elastic force of the elastic member (41).

5. The mowing head (1) of any one of the preceding claims, wherein the spool (11) and the housing (3) comprise devices with teeth (19, 21) and stops (23, 25) angularly offset around the axis (A-A) of rotation of the mowing head (1) and the axis (B-B) of the spool (11), and opposite to each other; wherein the teeth (19, 21) are arranged in such a way that the axial movement of the spool (11) within the housing (3) when the head (1) is rotating causes a controlled stepwise angular movement to deliver cutting line (F) from the spool (11) through the holes (3F) in the perimeter wall (3E).

6. The mowing head (11) of any one of the preceding claims, wherein the first opening (31) and the second opening (33) extend from the outer surface (13.1) to the inner surface (13.2) of the cylindrical wall of the central body (13).

7. The mowing head (1) of any one of the preceding claims, wherein the shank (27) is internally hollow and has an internal cavity having a diameter preferably of at least 8 mm.

8. The mowing head (1) of any one of the preceding claims, wherein the shank (27) comprises a coupling member (27.10) for coupling to a drive shaft of a grass trimmer.

9. The mowing head (1) of any one of the preceding claims, wherein the shank (27) is integral with a control member (41) for controlling an axial movement of the spool (11) within the housing (3), and wherein the spool (11) is associated with an elastic member (45) that stresses the spool (11) to an axial rest position, the axial movement of the spool (11) controlled by the control member (41) causing an axial displacement of the spool (11) against the stress of the elastic member (45).

10. The mowing head (1) of any one of the preceding claims, wherein the transverse passage of the cutting line (F) is provided in an axial position intermediate between a median plane of the first flange (15) and a median plane of the second flange (17).

11. The mowing head (1) of any one of the preceding claims, wherein in the inner space (35) of the spool (11) at least one guide channel (38) is defined for the cutting line (F), extending from one to the other of the first opening (31) and second opening (33) in the cylindrical wall of the central body (13) of the spool (11).

12. The mowing head (1) of claim 11, when dependent on at least claim 6, wherein the at least one guide channel (38) extends around the shank (27) of the spool (11).

13. The mowing head (1) of any one of the preceding claims, wherein, when the mowing head (1) is mounted with the spool (11) inside it, the inner space (35) of the spool (11) is closed by a first closing wall (37) and a second closing wall; and wherein the first closing wall and the second closing wall are transverse to the axis of the spool and spaced from each other in the direction of the axis (B-B) of the spool (H).

14. The mowing head (1) of claim 13, wherein at least one of the first and second closing walls is integral with the central body (13) of the spool (11).

15. The mowing head (1) of claim 13 or 14, wherein: the first closing wall and the second closing wall are integral with the body (13) of the spool (11); or one of the first and second closing walls is formed by the first housing portion (3 A) or the second housing portion (3B) and the other of the first and second closing walls is integral with the spool (11).

16. The mowing head (1) of any one of the preceding claims, comprising a rotary knob (51), angularly constrained to the spool (11) when the spool (11) is inserted in the housing (3); wherein the rotary knob (51) is accessible from outside the housing (3) and is coaxial with the axis (A-A) of rotation of the mowing head (1); and wherein the rotation of the rotary knob (51) around the axis (A-A) of rotation of the mowing head (1) causes the spool (11) to rotate relative to the housing (3), around theaxis (A-A) of rotation of the mowing head (1)17. The mowing head (1) of claim 16, when dependent on at least one of claim 11 or 12, wherein at least one of the first and second closing walls is formed by the rotary knob (51).

18. The mowing head ( 1 ) of claim 16 or 17, wherein the rotary knob (51) has a cavity (51.10) surrounded by an annular edge (51.11) adapted to protect a drive of a grass trimmer when the head is in use.

19. The mowing head (1) of claim 18, wherein the cavity (51.10) of the rotary knob (51) has an inner diameter of 40 mm or more, and wherein preferably the annular edge (51.11) has a height (H) of 2 mm or more, preferably of 3 mm or more, more preferably of 5 mm or more, even more preferably comprised between 5 mm and 20 mm, or between 5 mm and 15 mm.

20. The mowing head (1) of any one of the preceding claims, wherein the outer surface (13.1) of the cylindrical wall of the central body (13) of the spool (11) has a maximum diameter of 100 mm, preferably 90 mm or less.

21. The mowing head (1) of any one of the preceding claims, wherein the transverse passage for the cutting line (F) through the spool (11) defines a curvature whose concavity faces one of the first housing portion (3A) and second housing portion (3B) that, in use, faces the vegetation to be cut.

22. A spool (11) for winding a cutting line (F), insertable into the housing and comprising:A) a central body (13) having a cylindrical wall, coaxial with an axis (B-B) of the spool (11); wherein the cylindrical wall comprises an outer surface (13.1), coaxial with the axis (B-B) of the spool (11) and forming a winding surface for winding the cutting line (F);B) a first flange (15) and a second flange (17), spaced from each other along the axis (B-B) of the spool; wherein an annular space for winding the cutting line (F) is defined between the first flange (15), the second flange (17), and the outer surface (13.1) of the cylindrical wall of the central body (13), forming in this way a stock consisting of coils wound around the outersurface (13.1) of the central body (13); wherein: the cylindrical wall of the central body (13) of the spool (11) has, between the first flange (15) and the second flange (17), a first opening (31) and a second opening (33) angularly offset from each other around the axis (B-B) of the spool (11); the first opening (31) and the second opening (33) are connected to each other through an inner space (35) of the spool (11), surrounded by the cylindrical wall of the central body (13) of the spool (11); the inner space (35) defines a transverse passage for the cutting line (F): the spool (11) comprises a shank (27) coaxial with the cylindrical wall of the central body (13) of the spool (11); and the transverse passage for the cutting line (F) extends around the shank (27), between the shank (27) and the cylindrical wall of the central body (13) of the spool (11).

23. The spool (11) of claim 22, comprising one or more of the following features: the shank (27) is hollow; the first opening (31) and the second opening (33) extend from the outer surface (13.1) to the inner surface (13.2) of the cylindrical wall of the central body (13); the shank (27) comprises a coupling member for coupling to a drive shaft of a grass trimmer; the transverse passage of the cutting line (F) is provided in an axial position intermediate between a median plane of the first flange (15) and a median plane of the second flange (17); at least one guide channel (38) for the cutting line (F) is defined in the inner space (35) of the spool (11), the guide channel extending from one to the other of the first opening (31) and second opening (33) in the cylindrical wall of the central body (13) of the spool (11); the guide channel (38) extends around the shank (27) of the spool (11); the inner space (35) of the spool (11) is closed by a first closing wall and a second closing wall; and wherein one or both the first closing wall and the second closing wall are transverse to the axis (B-B) of the spool (11) and spaced from each other in the direction of the axis (B-B) of the spool (11).

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