FR2623365A1 - CUTTING HEAD FOR A GRASS TRIMMER - Google Patents

Abstract

The cutting head 1 comprises a housing 12 in two parts in which a spool 19 on which is wound a cutting wire 10 is mounted so as to be able to rotate step by step. The ends 20 of the cutting wire 10 are outwardly through the guide bushes 22. The guide bushes 22 are arranged in the circumferential wall of the housing 12. To facilitate the passage of the ends 20 of the wire through the bushings. guide 22 when the coil 19 is in place, the plane of separation 13 between the two parts 14 and 15 of the housing, attached to the bottom 16 of part 14 of the housing receiving the coil 19, is located below the radial median plane of the housing 12 or at the same level as the latter, the bores 21 of the guide bushes 22 lying approximately in this radial median plane.

Description

The invention relates to a cutting head

  for a motorized trimmer comprising a two-part casing rotating around an axis of rotation and composed of a body of

  base substantially in the form of a pot and a lid, inside

  laughing machine from which a coil is mounted on which a

  cutting line with at least one end exiting towards the ex-

  térieur by a guide placed in the wall of the casing.

  In the case of a cutting head described in the patent

  vet American US-PS 4 651 421, the housing cover is screwed onto the upper edge of the pot-shaped base body in which the spool carrying the wire roll is mounted so that it can be turned step by step. The ends of the cutting line are guided through the wall of the base body which is provided for this purpose with guide sleeves. Since, after installation in the housing, the coil is located entirely inside the basic body in the form of

  pot, it is difficult and complicated to get the

  mites of the cutting line from the inside to the outside through

to guide bushings.

  The object of the invention is to shape the head of

  cuts in such a way that the interior space-of the housing is

  core easily accessible to pass the cutting line when

  the spool is mounted and the cover removed.

  According to the invention, this object is achieved by the fact that the base body and the cover are contiguous along a

  housing separation plane, and that, reported at the bottom of the housing

  ter, the guide is located at or above the plane of the

paration.

  In this embodiment of the housing, the cover has a relatively high circumferential wall which

  follows the wall of the basic body, in the plane of separation

  housing ration, said separation plane being approximately

  matively in the median radial plane of the housing or - reported

  at the bottom of the base body - below this median plane.

  When the spool is placed in the base body of the housing and the cover is removed, the wire roll is

  easily accessible from the side. This is why it is fa-

  eyelash grab the ends of the cutting line and pass them through the guides which are provided, preferably,

  in two raised wall sections of the base body.

  According to a particular characteristic, the guides are constituted respectively by the bore of a guide sleeve having, on the periphery, an annular groove in which respectively engages an edge section of the

  walls of the base body and cover.

  According to another particular characteristic, the sec-

  edge of the wall of the basic body delimits a hollow

  approximately semicircular in which the socket

  guide is maintained by snap-fastening.

  It is advantageous that the guides are respective-

  ment provided on a bar forming part of the wall of the base body and engaging with precision in a recess

of the cover wall.

  An advantageous feature is that the

  casing separation plan is stepped near the guides

  dages, said guides being located respectively in a section of the separation plane with respect to which the two

  longer remaining sections of the separation plane are de-

  wedged towards the bottom of the base body.

  In a preferred embodiment of the invention,

  it is expected that the longer sections of the separation plane

  tion lie approximately in the plane of a coil flange, said flange being oriented with its front face

  outside towards the bottom of the base body.

  The following description, next to the drawings

  appended as nonlimiting examples, will allow

  understand how the invention can be put into practice.

  Figure 1 shows a grass trimmer with cutting head; 2 shows, on a larger scale, an axial section of the cutting head of FIG. 1; Figure 3 shows a partial side view of the cutting head; Figure 4 shows a top view of the cutting head with the cover removed, the upper part of the drawing showing the guide sleeve with the passage of

  the end of the wire and the area inside the spool indi-

  schematically, while in the lower part

  lower of the drawing these elements have been omitted.

  Fig. 1 shows a grass trimmer 2 with a L0 cutter head 1. The apparatus is designed to cut and mow grass, herbaceous plants and the like respectively. It is carried by an operator 3 by means of a harness 4 and guided by hand via handles 5 in the form of handlebars which are fixed approximately in the middle of a guide tube 6. At the upper end of the guide tube 6 is arranged a drive motor 7 which can be produced in the form of an internal combustion engine. The lower end of the guide tube 6 is provided with an elbow fitting 8 on which

  the cutting head 1 is removably attached.

  The cutting head 1 is driven by the motor 7 by

  through a transmission device located inside

  of the guide tube 6 and it then rotates around an axis 9. In order to shield against the cutting line 10 coming out of the cutting head 1, the connection 8 of the grass trimmer 2 is equipped with a cover protection 11 which can be provided with a wire cutter for the cutting line 10 whose effective length

  for cutting is thus set at an upper limit value.

  The cutting head has a substantially cy-

  lindrique 12 which consists of a basic body 14 and a cou-

  circle 15 and which is therefore produced in two parts. The body of

  base 14 is shaped in a pot, with a bottom 16 and a cy-

  lindrique 33. The cover 15 also has a pot shape with a cylindrical wall 34. The edges of the body

  base 14 and cover 15 directed towards each other presented

  try the shape of a circle ring, except for the re-

  gion of two connecting bars, and they constitute the separation plane 13 of the casing 12 (fig. 2 and 3). On the bottom 16 of the

  base body 14 is shaped like a hub 17 coaxial with axis 9.

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  The cover 15 is placed substantially parallel to the bottom

  16 and it can be connected to the base body 14 via

  diary of a snap-in assembly provided on the circled wall

case 12.

  In the interior space 18 of the casing 12 is a coil 19 which is arranged coaxially with respect to the axis 9 and mounted in a rotary manner. On the reel 19 is wound a cutting wire 10 which can be produced in the form of a

plastic twine.

  The cutting line 10 has two free ends 20 which are extended outwards through the bores 21 of two guide bushings 22 at the periphery of the casing 12 and kept taut, during the rotation of the cutting head, by the centrifugal force. The two bores 21 constitute

  then guides for the cutting line 10 at the cutting points

  sition at the ends 20 of the cutting line. The axes of the

  wise of the two diametrically opposed guide bushes 22 lie approximately in the median radial plane of the

  casing 12 and the coil 19 which has two flanges pa-

  Rails 23 and 24 which delimit the space for the wire roll.

  In the coil 19 is disposed a coupling sleeve

  plement 25 of which a front flange 26 is placed in a

  annular slot on the bottom 16 of the base body.

  In the housing 12 is further provided a pot-shaped coupling member 27 which passes through the coupling sleeve 25 and can be moved against the force of a

  cylindrical compression spring 28 which is arranged

  substantially inside the coupling member 27 and coaxially with respect thereto. The inner face of the coupling sleeve 25 is provided with a plurality of projecting lugs 29 with which are associated, on the periphery of the coupling member 27, stops 30 projecting in the radial direction. The pins 29 and the stops 30 are arranged at determined intervals and distributed on different radial planes. Thus, the cutting line 10 can respectively be advanced step by step by a predetermined amount by rotation

coil 19 step by step.

  The cylindrical spring 28 is supported on the faces

  inner fronts of the coupling member 27 and respec-

  tively of the hub 17. Its ends are each guided with

  several turns on a tube 31 of the hub 17 and respectively

  on an opposite tube 32 formed on the inner face

of the coupling member 27.

  As appears from figs. 2 and 3, the guide bushings 22 are arranged symmetrically with respect to a section 13b of the separation plane 13. At the periphery of

  each guide sleeve 22 has an annular groove

  area 35 in which engages, on one of the sides, a sec-

  roughly semi-circular edge 36 of the cover wall

  ring 34 and, on the other side, an edge section 37 also

  semi-circular ment which is shaped on a bar 39 of the wall 33 of the base body 14 and which delimits a semi-circular recess 38 in which the guide sleeve 22 is

maintained by snap-fastening.

  The bars 39 are produced in the form of ta-

  lons of the wall 33 of the base body 14 and they engage with precision in the recesses 40 of the cover wall

  34 which are diametrically opposed to them.

  Due to the bars 39, the separation plane 13 is stepped so as to form the two sections 13b which are

  much shorter than the two sections 13a of the floor plan

  paration in the shape of a partial circle ring. Sections 13a

  have relative to the bottom 16 of the base body 4 a

  relatively small tance which is equal to about a quarter of the interior height of the interior space 18. The distance of the other sections 13b of the separation plane 13 from the bottom 16 is approximately twice as large so that these sections 13b are located approximately on the map

  radial median of the casing 12. Sections 13a of the separation plane

  ration 13 are located approximately at the level of the flange 23 of

  the coil which is directed towards the bottom 16 of the base body 14.

  When the cover 15 is removed, the coil 19 with the roller

  the wire water placed in the base body 14 is therefore

  clear to a large extent, while the guide bushings

  dage 22 are engaged on the narrow bars 39. It

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  is then possible to pass the two ends 20 of the cutting wire 10 in the guide bushings 22 without the housing being annoying. After the introduction of the cover 15, the wall 34 thereof surrounds with its edge sections 41 the two bars 39 so that the housing 12 is closed everywhere.

  The conformation of the casing 12 also allows a

  simple tage of the cutting head members to be installed, as well as an easy replacement of the wire roll because the interior space of the housing is easily accessible when

the cover 15 is removed.

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Claims (6)

  1. - Cutting head for a motorized grass trimmer   taking a casing in two parts rotating around an axis of rotation and composed of a base body substantially in the form of a pot and a cover, inside which is mounted a coil on which is wound a cutting wire at least one end of which is extended outwards by a guide placed in the wall of the casing, characteristic that the base body (14) and the cover (15) are contiguous along a separation plane (13) of the casing (12), and that,   attached to the bottom of the base body (14), the guide (21) is   kills at or above the separation plane (13).   2. - cutting head according to claim 1, character-   in that the guides (21) are made up respectively   ment by the bore of a guide sleeve (22) having, on the periphery, an annular groove (35) in which   engages respectively an edge section (36 and 37) of the   kings (33 and respectively 34) of the basic body (14) and the cover (15).   3. - cutting head according to claim 2, character-   mock in that the edge section (37) of the wall (33) of the   basic body (14) defines an approximate recess (38)   semicircular in which the guide sleeve (22) is held in place by snap-fastening.   4. - Cutting head according to any one of the res-   dications 1 to 3, characterized in that the guides (21) are respectively provided on a bar (39) forming part of   the wall (33) of the base body (14) and engaging with precision   sion in a recess (40) of the cover wall (34).   5. - Cutting head according to any one of the res-   dications 1 to 4, characterized in that the separation plane (13) of the housing (12) is stepped near the guides (21),   said guides (21) being located respectively in a sec-   tion (13b) of the separation plane (13) with respect to which   the two longer longer sections (13a) remaining of the floor plan   trim (13) are offset towards the bottom (16) of the body base (14). 8 2623365   6. - cutting head according to claim 5, character-   in that the longer sections (13a) of the section plane   paration (13) lie approximately in the plane of a flange (23) of the coil (19), said flange (23) being oriented with its outer front face towards the bottom (16) of the body of base (14).