阅读说明：本技术 用于线绳收割头的线绳卷筒 (Cord reel for cord harvesting head ) 是由 S·施密特 S·汉 S·扎佩 C·布伦纳 A·雷塔伯 B·佩特森 S·布赫纳 于 2020-12-04 设计创作，主要内容包括：本发明涉及一种用于线绳收割头的线绳卷筒。线绳卷筒(7)包括至少两个保持件对(21、22)。第一保持件对(21)和第二保持件对(22)分别包括关联于第一卷筒腔(8)的第一线绳保持件(10、10’)和关联于第二卷筒腔(9)的第二线绳保持件(11、11’)。每个线绳保持件(10、10’、11、11’)都包括用于容纳切割线绳端部的开口(14、14’、15、15’)。第一保持件对(21)的线绳保持件(10、11)的开口(14、15)的直径(a)大于第二保持件对(22)的线绳保持件(10’、11’)的开口(14’、15’)的直径(b)。每一个保持件对(21、22)的线绳保持件(10、10’、11、11’)的开口(14、14’、15、15’)都具有围绕旋转轴线(4)测得的150°至210°的角度间隔(α)。(The invention relates to a cord reel for a cord harvesting head. The cord reel (7) comprises at least two pairs of holders (21, 22). The first holder pair (21) and the second holder pair (22) comprise a first cord holder (10, 10') associated with the first reel cavity (8) and a second cord holder (11, 11') associated with the second reel cavity (9), respectively. Each cord holder (10, 10', 11') comprises an opening (14, 14', 15') for receiving an end of a cutting cord. The diameter (a) of the openings (14, 15) of the cord holders (10, 11) of the first pair (21) is greater than the diameter (b) of the openings (14', 15') of the cord holders (10', 11') of the second pair (22). The openings (14, 14', 15') of the cord retainers (10, 10', 11') of each retainer pair (21, 22) have an angular interval (a) of 150 ° to 210 ° measured around the rotation axis (4).)

1. Line drum for a line take-up head, wherein the line drum (7) comprises a first drum chamber (8) and a second drum chamber (9) for winding in each case one cutting line (6) and an axis of rotation (4), wherein the line drum (7) comprises at least two pairs of holders (21, 22), wherein a first holder pair (21) of the at least two pairs of holders (21, 22) and a second holder pair (22) of the at least two pairs of holders (21, 22) each comprise a first line holder (10, 10') associated with the first drum chamber (8) and a second line holder (11, 11') associated with the second drum chamber (9), wherein each line holder (10, 10', 11') comprises an opening (14, 14 '; for accommodating an end of a cutting line, 15. 15'), wherein the diameter (a) of the opening (14, 15) of the cord holder (10, 11) of the first pair (21) of holders is larger than the diameter (b) of the opening (14', 15') of the cord holder (10', 11') of the second pair (22) of holders,

characterized in that the openings (14, 14', 15') of the cord retainers (10, 10', 11') of each retainer pair (21, 22) have an angular interval (a) of 150 ° to 210 ° measured around the rotation axis (4).

2. The wire reel according to claim 1, characterized in that the wire holders (10, 10', 11') of at least one holder pair (21, 22) are at least partially located in a longitudinal plane (5) containing the axis of rotation (4).

3. The rope reel according to claim 1, characterized in that the rope holders (10, 10', 11') of at least one holder pair (21, 22) are formed by rope chambers (12, 13) of the same type.

4. The cord reel according to claim 3, characterized in that the cutting cord (6) is insertable into the cord cavity (12, 13) only via an opening (14, 14', 15') of the cord holder (10, 10', 11').

5. The rope drum according to claim 3, characterized in that the rope chamber (12, 13) is closed at its side opposite the opening (14, 14', 15') and forms a stop (22) for the cut rope end.

6. The rope drum according to claim 3, characterized in that the rope drum (7) has a direction of rotation (20) and the openings (14, 14', 15') are configured at a side of the rope chamber (12, 13) which is located forward in the direction of rotation (20).

7. The rope reel according to claim 1, characterized in that the diameter (b) of the opening (14', 15') of the rope holder (10', 11') of the second holder pair (22) is at most 90% of the diameter (a) of the opening (14, 15) of the rope holder (10, 11) of the first holder pair (11).

8. The rope drum according to claim 1, characterized in that the rope drum (7) comprises a first drum wall (16), a second drum wall (18) and an intermediate wall (17) arranged between the first drum wall (16) and the second drum wall (18), wherein the first drum wall (16), the second drum wall (18) and the intermediate wall (17) are connected to each other by a circumferential wall (19) extending in the direction of the rotation axis (4), wherein the rope holders (10, 10', 11') abut against the intermediate wall (17) in the direction of the rotation axis (4).

9. Rope drum according to claim 8, characterized in that the first rope holder (10, 10') of one holder pair (21) and the second rope holder (11, 11') of the other holder pair (21) are arranged mirror-symmetrically with respect to the intermediate wall (17).

10. The rope drum according to claim 1, characterized in that the rope drum (7) has a contour (31) at the end faces for a tandem arrangement (30).

11. The cord reel according to claim 1, characterized in that the cord reel (7) has at least one cord channel (35, 35') therethrough, through which the cutting cord (6) can be inserted and wound.

12. The rope drum according to claim 1, characterized in that the rope channel (35, 35') has an inlet opening (36) and an outlet opening (37), wherein the inlet opening (36) and the outlet opening (37) are arranged centrally in circumferential direction between the two rope holders (10, 10', 11') of a holder pair (21, 22).

13. The rope drum according to claim 1, characterized in that an inlet opening (36) and an outlet opening (37) of the rope channel (35, 35') are arranged in the intermediate wall (17).

14. A cord reel for a cord harvesting head, wherein the cord reel (7) comprises at least one reel chamber (8, 9) for winding a cutting cord (6) and an axis of rotation (4), wherein the wire reel (7) comprises a first reel wall (16) for defining the at least one reel chamber (8, 9) in the direction of the rotation axis (4) and an operating device (32) arranged outside the reel chamber (8, 9) adjoining the first reel wall (16) in the direction of the rotation axis (4), wherein the handling device (32) has a holding projection (33) extending radially relative to the rotational axis (4) for being held partially behind by a user, characterized in that at least one holding recess (34) is formed in the first drum wall (16) opposite the holding projection (33).

15. Cord reel according to claim 14, characterized in that the cord reel (7) has an intermediate wall (17) and at least one through-going cord channel (35, 35') extending at least partially in the intermediate wall (17), the cutting cord (6) can be completely inserted through the cord reel (7) through the cord channel and wound, wherein the cord channel (35, 35') has an inlet opening (36) and an outlet opening (37), wherein the inlet opening (36) and the outlet opening (37) have an angular spacing (β) of 150 ° to 210 ° measured around the axis of rotation (4), wherein the at least one holding pocket (34) is arranged in a circumferential region (38), the circumferential area is located between the inlet opening (36) and the outlet opening (37).

Technical Field

The invention relates to a cord reel (Fadenscoil) for a cord harvesting head (Fadensmaehkopf).

Background

The brush cutter is used for harvesting grass, shrubs and the like. For this purpose, the wire harvesting head with the tool is driven in rotation about the axis of rotation of the wire harvesting head, whereby the grass is cut off when it comes into contact with the tool. As a tool, in particular cutting cords are used, which are subjected to a certain wear during the operation of the cord cutting head. In order to be able to readjust the cutting cord, the cutting cord can be unwound from the cord reel of the cord cutting head, so that the cutting can be carried out with the cord cutting head without having to provide a complete replacement of the cutting cord and without impairing the cutting function.

It is known that the cord reels of some cord harvesting heads comprise two reel chambers for winding up the cutting cord separately. Two cord holders are provided at each reel chamber, which enable clamping of cut cords of different thicknesses. A disadvantage of such a cable harvesting head is that very high loads occur during operation of such a cable harvesting head.

Disclosure of Invention

The object of the invention is to improve a cord reel in such a way that the load acting on the cord reel during operation of the cord harvesting head is reduced and at the same time an ergonomic handling of the cord reel for the user is achieved.

This object is achieved by a cord reel for a cord harvesting head, wherein the cord reel comprises a first and a second reel chamber for winding a cutting cord each and an axis of rotation, wherein the cord reel comprises at least two pairs of holders, wherein a first holder pair of the at least two pairs of holders and a second holder pair of the at least two pairs of holders comprise a first cord holder associated with the first reel cavity and a second cord holder associated with the second reel cavity, respectively, wherein each cord holder comprises an opening for receiving a cut cord end, wherein the diameter of the opening of the cord holder of a first pair of holders is larger than the diameter of the opening of the cord holder of a second pair of holders, wherein the openings of the cord retainers of each retainer pair have an angular spacing of 150 ° to 210 ° measured about the axis of rotation.

The object is also achieved by a line drum for a line cutting head, wherein the line drum comprises at least one drum chamber for winding a cutting line and a rotation axis, wherein the line drum comprises a first drum wall for defining the at least one drum chamber in the direction of the rotation axis and an actuating device arranged outside the drum chamber adjacent to the first drum wall in the direction of the rotation axis, wherein the actuating device has a holding projection (halovorrsprune) extending radially with respect to the rotation axis for a user to hold partially behind, wherein at least one holding recess (Griffmulde) is formed in the first drum wall opposite the holding projection.

The cord reel according to the invention is based on the recognition that: during operation of the cord cutting head, high loads act on the cord cutting head due to unbalance of the cord drum. This imbalance is primarily due to the placement of the cutting cord in the spool cavity, which in turn is caused by the position of the cord holder. In order to reduce the unbalance at the rope drum, the cutting ropes are arranged such that the centrifugal forces acting on the rope drum cancel each other out or are in force balance.

The cord reel according to the present invention comprises at least two pairs of holders. A first of the at least two pairs of retainers and a second of the at least two pairs of retainers include a first cord retainer associated with the first spool cavity and a second cord retainer associated with the second spool cavity, respectively. Each cord holder includes an opening for receiving an end of a cut cord. The diameter of the opening of the cord holder of the first holder pair is greater than the diameter of the opening of the cord holder of the second holder pair. The openings of the cord retainers of each retainer pair have an angular spacing of 150 ° to 210 ° measured about the axis of rotation.

To run the cord take-up head, the cutting cord is wound onto a cord reel. For this purpose, the cutting cord is inserted into the openings of the cord holders of the holder pairs, respectively, and is wound in the respective drum chambers at the circumference of the cord drum. During operation of the cord cutting head, centrifugal forces act on the cord holder and cut the cord. Since the openings of the wire holders of each holder pair and the cutting wire clamped therein are arranged offset to one another about the axis of rotation, the centrifugal forces acting on the cutting wire substantially cancel one another out. The imbalance of the cord reel and the load on the cord cutting head are reduced. It has furthermore been shown that the insertion of the cutting cord in cord holders arranged offset to one another is significantly simpler for the user. The holder pairs through their different sized openings form an aid for the user as to which holder pair to use for the respective cutting cord or into which cord holder the respective cutting cord is to be inserted.

The cord retainers of at least one retainer pair preferably lie at least partially in a longitudinal plane containing the axis of rotation. Preferably, the cord holders of the holder pair are arranged rotationally symmetrically to each other about the axis of rotation in a viewing direction of the axis of rotation. By means of this symmetrical arrangement of the thread holder, a balanced mass distribution of the thread drum, in particular in the wound cutting thread, can be achieved and imbalances in the rotation of the thread drum are avoided.

It is advantageously provided that the cord retainers of the retainer pair are formed by cord chambers of the same type. The cutting cord is preferably insertable into the cord cavity only through the opening of the cord holder. Therefore, the cutting cord can only be inserted on one side of the cord holder, thereby avoiding an erroneous winding direction of the cutting cord onto the cord reel. The cord cavity is preferably closed at its side opposite the opening and forms a stop for cutting the end of the cord. The cutting cord is preferably moved to a stop as it is threaded into the cord chamber. The cutting cord ends of the two cutting cords thus each rest against a stop of the cord chambers of the holder pair, whereby a symmetrical arrangement of the cutting cords can be ensured.

The cord reel has a direction of rotation, wherein the opening is preferably configured at a side of the cord chamber which is located in front in the direction of rotation. This direction of rotation corresponds to the direction of rotation of the line drum in the course of the line harvesting head.

It is advantageously provided that the diameter of the opening of the cord holder of the second holder pair is at most 90% of the diameter of the opening of the cord holder of the first holder pair. Due to the different sized openings of the cord holder, cutting cords with different diameter sizes may be held in the cord holder. Whereby a corresponding cutting cord with a diameter adapted to the purpose of use can be provided.

It is advantageously provided that the cord reel comprises a first reel wall, a second reel wall and an intermediate wall arranged between the first reel wall and the second reel wall. The first drum wall, the second drum wall and the intermediate wall are preferably interconnected by a circumferential wall extending in the direction of the axis of rotation. The wire holder preferably rests against the intermediate wall in the direction of the axis of rotation. By arranging the cord holder at the intermediate wall, the inertial forces that may occur at the cord reel during operation of the cord harvesting head are reduced. The first cord holder of one holder pair and the second cord holder of the other holder pair are preferably arranged mirror-symmetrically with respect to the intermediate wall. This arrangement is also used for a balanced mass distribution of the cord reel.

The cord reel preferably has a contour for the tandem at the end side. During operation of the cable take-off head, the cable drum is connected to the housing of the cable take-off head in the rotational direction in a form-fitting manner via the contour. During the actuation of the tandem arrangement, the form fit between the housing of the cable take-up head and the cable drum is eliminated. The wire drum may then be rotated in an unwinding direction relative to the housing, thereby causing the cutting wire to unwind from the wire drum. The unwinding process is carried out in the mounted state of the wire rope reel. Removal of the cord harvesting head is not necessary.

The cord reel preferably has at least one through-going cord channel through which a cutting cord can be inserted and wound. The through passage enables a user to wind the cutting cord in the mounted state of the cord harvesting head. Thus, the user inserts the cutting cord into the cord channel, wherein the cord reel is then rotated relative to the cord take-up head. The now free end of the cutting cord is correspondingly wound in one of the two reel chambers. The cord channel preferably has an inlet opening and an outlet opening, wherein the inlet opening and the outlet opening are preferably arranged centrally in the circumferential direction between the two cord holders of the holder pair. The inlet opening and the outlet opening of the cord channel are preferably arranged in the intermediate wall. This facilitates a balanced mass distribution of the cord reel for avoiding unbalance.

As a further independent invention, it is provided that the cable drum comprises an actuating device arranged outside the drum chamber, which is adjacent to the first drum wall in the direction of the axis of rotation. The actuating device has a holding projection extending radially with respect to the axis of rotation for partial rearward holding by a user. At least one holding recess is formed in the first drum wall opposite the holding projection.

The operating device is used for operating the tandem arrangement of the cord harvesting head. For this purpose, the cable drum can be pulled against the spring force in the direction of the axis of rotation, whereby the form-fitting connection between the housing and the cable drum is eliminated and the cable drum is subsequently rotated relative to the housing in the unwinding direction. The cord reel is held by the user at its handling device and is pulled in a direction away from the housing. In this case, the user holds the holding projection of the actuating device behind. By the at least one holding recess, which is formed in the first drum wall opposite the holding projection, the user has more space for holding the holding projection behind. The grip recess thus enables the user to better grip the handling device.

The cable drum preferably has an intermediate wall and at least one through-going cable channel running at least partially in the intermediate wall, through which the cutting cable can be inserted, preferably completely, through the cable drum and wound. The cord channel preferably has an inlet opening and an outlet opening. The inlet opening and the outlet opening have, in particular, an angular spacing of 150 ° to 210 ° measured about the axis of rotation. The at least one holding pocket is preferably arranged in a circumferential region which is located between the inlet opening and the outlet opening. Preferably, a plurality of holding pockets, in particular two holding pockets, are arranged in the circumferential region.

The inlet opening and the outlet opening of the cord channel at the intermediate wall cause a local thickening of the intermediate wall. The drum chambers each have a height measured in the direction of the axis of rotation. The height of the reel chamber decreases at a local thickening of the intermediate wall. In order not to reduce the height of the drum chamber and thus also the space available for winding the cutting cord additionally, at least one holding pocket, in particular two holding pockets, is arranged in the circumferential region. Thereby providing sufficient space between the thickening at the intermediate wall and the first reel wall for winding up the cutting cord. At the inlet opening and the outlet opening of the intermediate wall, no additional narrowing of the reel chamber occurs, so that easy winding of the cutting cord is also ensured.

Drawings

Further features of the invention can be taken from the description, the drawings, in which embodiments of the invention that are described in detail below are reproduced. Wherein:

FIG. 1 shows a schematic view of a brush cutter held by a user;

FIG. 2 illustrates a side view of one embodiment of a cord harvesting head;

fig. 3 shows a top view of the cord harvesting head according to fig. 2;

fig. 4 shows a cross-sectional view of the cord harvesting head according to fig. 3 in the direction of arrow 4;

fig. 5 shows a perspective view of a cord reel according to the present invention;

fig. 6 shows a side view of the cord reel according to fig. 5;

fig. 7 shows a side cross-sectional view of the cord reel through the cord holder;

fig. 8 shows a cross-sectional view of the cord reel according to fig. 6 in the direction of arrow 8;

fig. 9 shows a side view of the wire drum in a position rotated 90 ° about the rotation axis relative to fig. 6;

fig. 10 shows a side view of an alternative embodiment of a cord reel;

fig. 11 shows a perspective view of an alternative embodiment of a cord reel.

Detailed Description

Fig. 1 shows a brush cutter 1 in a schematic view. The brush cutter 1 is held by a user 26. The brush cutter 1 has a rear end with a rear housing 27 from which projects the drive shaft 2 (fig. 2) and a front end. A rod 28 connects the rear end to the front end. At the lever 28, a handle 29 for controlling the brush cutter 1 is arranged. The wire harvesting head 3 is coupled to the front end of the brush cutter 1. The wire harvesting head 3 is fixed at the drive shaft 2 and is driven in rotation about the axis of rotation 4 in the direction of rotation 20 by a drive motor 59, which is only schematically shown. The drive motor 59 is arranged in the rear housing 27, wherein the drive shaft extends in the rod 28. It may be provided that the drive shaft is directly connected in the rod with the drive shaft 2 for the wire harvesting head 3, so that no transmission is interposed. In an alternative embodiment, which is not shown, the drive motor 59 (which is in particular an electric motor) can also be arranged at a not shown front housing, which is arranged at the front end. Advantageously, a transmission is also present in the front housing. The cord harvesting head 3 is covered by a protective cover 40 at the side which in operation faces the user 26. The wire harvesting head 3 has at least one tool which in the present embodiment serves as a cutting wire 6, 6' for cutting a cutting object, such as grass, bushes or the like. At the cable harvesting head 3, a lower side 42 is formed, which in operation faces the base 41 and is arranged at the side of the cable harvesting head 3 facing away from the shaft 28. The upper side 43 of the cord harvesting head 3 is configured at the side of the cord harvesting head 3 facing the shaft 28. The protective clothing to be forcibly worn by the user 26 for the operation of the brush cutter 1 is not shown in the simplified illustration of fig. 1.

The cord harvesting head 3 is shown in a side view in fig. 2. The wire harvesting head 3 comprises a rotation axis 4 about which the wire harvesting head 3 rotates in operation of the brush cutter. For this purpose, the wire harvesting head 3 is driven by a drive shaft 2, which is only schematically shown. Furthermore, the cord harvesting head 3 comprises a housing 44 and a cord reel 7 arranged at the housing. The housing 44 of the cord harvesting head 3 is configured pot-like and in this embodiment comprises a top cover 45 and a surrounding wall 46. The cover 45 extends away from the axis of rotation 4 in the radial direction starting from the axis of rotation 4. The cap 45 is in particular oriented approximately perpendicular to the axis of rotation 4 of the cord harvesting head 3. The peripheral wall 46 adjoins the top cover 45 and extends in the direction of the axis of rotation 4.

As shown in fig. 2 and 3, the cutting cords 6, 6' may be secured at the cord harvesting head 3. In a preferred embodiment it is possible to secure up to two cutting cords 6, 6', i.e. a first cutting cord 6 and a second cutting cord 6'. The cutting cord 6, 6' extends from the housing 44 of the cord harvesting head 3. For this purpose, in the preferred embodiment, two cable openings 47 are formed in the circumferential wall 46 of the housing 44, which are opposite one another with respect to the axis of rotation 4 and through which the cutting cables 6, 6' project from the housing 44. In an alternative embodiment of the cord harvesting head 3, it may be expedient to provide a further number of cord openings 47 and a further number of cutting cords 6, 6'.

As shown in fig. 4, a hollow pin 60 extends from the cover 45 of the housing 44 coaxially with the axis of rotation 4. The tenon 60 is formed at an inner side 61 of the cap 45 facing the cord reel 7. The cord reel 7 is arranged on the circumferential side of the tenon 60. The wire drum 7 is rotatably supported on the tenon 60 of the housing 44 and movably in the direction of the axis of rotation 4 (i.e., in the axial direction). The cord reel 7 is releasably held on the tenon 60 of the housing 44 by means of the fixing element 48. The fastening element 48 is designed as a screw element and is screwed to an intermediate element 62 which is fixedly connected to the pin 60. Between the wire rope reel 7 and the fixing element 48, a spring element 49 is arranged, which in the present embodiment is configured as a helical spring. The spring element 49 bears at one end against the inner side of the fixing element 48 facing the cord reel 7. The other end of the spring element 49 abuts against a stop contour 63 of the line drum 7. The spring element 49 applies a spring force to the cable drum 7, wherein the spring force acts in the direction of the axis of rotation 4 toward the cover 45. In the operating position 57 of the wire harvesting head 3, the wire drum 7 is pressed by the spring element 49 against the housing 44 in the direction of the axis of rotation 4.

As shown in fig. 4, the cord harvesting head 3 comprises a tandem arrangement 30 which enables winding and unwinding of the cutting cords 6, 6' from the cord reel 7 in the mounted state of the cord harvesting head. The tandem arrangement 30 is formed by a contour 31 of the wire drum 7 and a counter-contour 50 of the housing 44 of the wire harvesting head 3, which co-operates with the contour 31. The contour 31 is formed on an end face 64 of the cable drum 7 facing the cover 45 of the housing 44. The mating contour 50 is formed on the inner side 61 of the cover 45 of the housing 44. The profile 31 is constructed from a plurality of ramps 51 arranged in the circumferential direction. The ramp 51 has an engagement surface 52 which is located at the rear end of the ramp 51 with respect to the direction of rotation 20 and which is oriented parallel to the axis of rotation 4. The ramp 51 also includes a back surface 53 that is contiguous with the engagement surface 52 and is oriented obliquely with respect to the engagement surface 52. In the operating position 57, the mating contour 50 of the housing 44 and the contour 31 of the wire drum 7 form a positive-locking connection in the direction of rotation 20. As a result, the cable drum 7 is connected to the housing 44 in a rotationally fixed manner in the operating position 57 in the direction of rotation 20.

As shown in fig. 4 and 5, the cord reel 7 includes a first reel chamber 8 and a second reel chamber 9. The first reel chamber 8 is a chamber in which the first cutting cord 6 can be wound. The second reel chamber 9 is a chamber in which the second cutting cord 6' may be wound. The cord reel 7 comprises a first reel wall 16, a second reel wall 18 and an intermediate wall 17 arranged between the first reel wall 16 and the second reel wall 18. The cord reel 7 further comprises a circumferential wall 19 interconnecting the first reel wall 16, the intermediate wall 17 and the second reel wall 18. The first spool chamber 8 is delimited in the direction of the axis of rotation 4 by a first spool wall 16 and an intermediate wall 17. In a radial direction towards the axis of rotation 4, the first spool chamber 8 is delimited by a circumferential wall 19. The second reel chamber 9 is delimited in the direction of the axis of rotation 4 by an intermediate wall 17 and a second reel wall 18. The second reel chamber 8 is delimited by a circumferential wall 19 in a radial direction towards the axis of rotation 4. In an alternative embodiment, it may be advantageous for the intermediate wall 17 to be formed only in sections, in particular in the region of the inlet opening 36 and the outlet opening 37 of the cable duct 35. In a further alternative embodiment, it may also be advantageous if no intermediate wall 17 is provided. Thereby partially or completely interconnecting the first and second spool chambers 8, 9. A web 54 is formed on the circumferential wall, which web extends radially with respect to the axis of rotation 4 in the direction of the axis of rotation 4 of the cord reel 7 and connects the circumferential wall 19 to a hub 55 of the cord reel 7. The cord reel 7 is supported via its hub 55 on a tenon 60 of the housing 44. A shoulder 56 with a stop contour 63 is formed on the hub 55 for receiving the spring element 49. The cable drum 7 is prestressed against the shoulder 56 of the hub 55 in the direction of the cover 45 of the housing 44 by means of the spring element 49. In the operating position 57, the first drum wall 16 abuts an end face of the circumferential wall 46 of the housing 44 facing away from the top cover 45. The inner space formed by the lid 45 and the circumferential wall 46 of the housing 44, in which the cord reel 7 is arranged, is thereby closed and protected against contamination.

As shown in fig. 4 and 5, the wire drum 7 comprises an operating device 32 for operating the stringing device 30. The handling device 32 is arranged outside the reel chambers 8, 9 adjacent to the first reel wall 16. In a preferred embodiment, the wire drum 7 is constructed integrally with its handling device 32. In this embodiment, the handling device 32 comprises a holding projection 33 extending radially outward with respect to the axis of rotation 4, which is configured for the user 26 to hold behind. The unwinding process of the cutting cords 6, 6' with the manipulation of the tandem 30 is briefly described below.

When winding the cutting cord 6, 6', the cutting cord is wound onto the cord reel 7 counter to the direction of rotation 20. For cutting the unwinding of the wire 6, 6', the wire drum 7 is rotated relative to the housing 44 about the rotation axis 4 in the unwinding direction 25 of the wire drum 7. Here, the free ends of the cutting cords 6, 6' project out of the cord opening 47 of the housing 44. The free ends of the cutting cords 6, 6 'are supported at the housing 44 during unwinding, so that the portions of the cutting cords 6, 6' protruding from the housing 44 are extended. The unwinding direction 25 of the wire drum 7 is opposite to the rotation direction 20.

To cut the unwinding of the cords 6, 6', the cord reel 7 may be pulled into the inoperative position in a direction away from the housing 44 against the spring force exerted by the spring element 49. The form fit between the contour 31 of the cable drum 7 and the counter contour 50 of the housing 44 is thereby eliminated. In a preferred embodiment, the pulling force required to overcome the spring force is applied by the user. For this purpose, the user can grip the cable drum at the holding projection 33 of the actuating device 32 in a simple manner and pull the cable drum 7 away from the cover 45 of the housing 44. In this inoperative position, the wire drum 7 is rotatable relative to the housing 44 in the unwinding direction 25 counter to the rotation direction 20. The cutting cords 6, 6' are unwound from the drum chambers 8, 9 in an unwinding direction 25 when the cord drum 7 rotates.

As shown in fig. 4 and 5, the holding projection 33 of the actuating device 32 forms with the first drum wall 16 a holding groove 65 into which a user can hold and thus hold the holding projection 33 behind. The holding groove 65 is delimited by the first reel wall 16 in the direction of the axis of rotation 4 towards the reel chambers 8, 9. The holding groove 65 is delimited from the drum chambers 8, 9 in the direction of the axis of rotation 4 by a holding projection 33. In order to enable better gripping of the holding projection 33 behind, at least one gripping recess 34 is provided in the first drum wall 16. In the preferred embodiment, two holding cavities 34 are provided. Other numbers of gripping cavities 34 may be suitable. The holding cavity 34 is formed in the first drum wall 16 in the form of an arch. The first drum wall 16 is thus arched. The holding recess 34 formed in the first reel wall 16 extends in the direction of the first reel chamber 8. The holding groove 65 has a width d measured outside the holding recess 34 in the direction of the axis of rotation 4₁Which corresponds to the spacing between the first reel wall 16 and the retaining projection 33. Furthermore, the holding groove 65 has a maximum width d measured in the direction of the axis of rotation 4 within the holding recess 34₂This width corresponds to the maximum spacing between the grip recess 34 and the holding projection 33. Maximum width d of the holding groove 65₂The width d of the holding groove 65₁At least 120%, especially at least130 percent. As shown in fig. 9, the gripping pockets 34 extend around the axis of rotation 4 within an angular interval of at least 40 °, in particular at least 60 °, preferably about 90 °. Due to the local increase in the width of the gripping groove 65 at the gripping recess 34, there is sufficient space to be able to grip the holding projection 33 of the handling device 32 behind in a simple manner.

As shown in fig. 5 and 6, the cord reel 7 has at least one cord channel 35 therethrough. The cutting cord 6, 6' may be fully inserted through the cord channel 35 and wound onto the cord reel 7. In the preferred embodiment, the cord reel 7 has two cord channels 35, 35' therethrough. The continuous thread channel 35 extends at least partially in the intermediate wall 17. The cord channel 35, 35' has an inlet opening 36 and an outlet opening 37. The inlet opening 36 and the outlet opening 37 of the cord channel 6, 6' have an angular spacing β, measured around the rotation axis 4, of preferably 150 ° to 210 °, in particular 160 ° to 200 °. The inlet opening 36 and the outlet opening 37 of the cord channels 35, 35' are arranged in the intermediate wall 17. The inlet opening 36, the outlet opening 37 and the cord channel 35 themselves result in a local thickening 66 of the intermediate wall 17. As shown in FIG. 6, the first spool chamber 8 has a first height h₁This first height corresponds to the distance between the first roller wall 16 and the intermediate wall 17, measured in the direction of the axis of rotation 4 outside the holding recess 34 and the thickening 66. Furthermore, the first spool chamber 8 has a second height h₂This second height corresponds to the distance between the first drum wall 16 and the intermediate wall 17 measured in the direction of the axis of rotation 4 at the thickening 66. The first reel chamber 8 has a reduced third height h measured in the direction of the axis of rotation 4 in the region of the holding recess 34₃. Third height h₃Corresponding to the spacing between the first reel wall 16 and the intermediate wall 17 at the holding pocket 34. Third height h₃Is less than the first height h₁. First height h of the first spool chamber 8₁Is larger than the second height h of the first reel chamber 8₂. In order to avoid an additional narrowing of the first reel chamber 8 at the thickening 66, the at least one holding recess 34 is arranged offset in the circumferential direction of the rotational axis 4 with respect to the thickening 66. Whereby the at least one holding pocket 34 is arranged on the line reel7, wherein the circumferential area 38 is located between the inlet opening 36 and the outlet opening 37 of the cord channel 35, 35'. An additional narrowing of the first roller chamber 8 at the thickening 66 of the intermediate wall 17 can thus be avoided. Due to the offset arrangement of the thickening 66 and the grip recess 34 in the circumferential direction of the axis of rotation 4, sufficient space is provided along the entire first reel chamber 8 for winding up the cutting cords 6, 6'.

As shown in fig. 5, the cord reel 7 includes two retainer pairs 21, 22. A first holder pair 21 of the two holder pairs 21, 22 comprises a first cord holder 10 associated with the first reel cavity 8 and a second cord holder 11 associated with the second reel cavity 9. The second holder pair 22 of the two holder pairs 21, 22 likewise comprises a first cord holder 10 'associated with the first reel chamber 8 and a second cord holder 11' associated with the second reel chamber 9. Each cord holder 10, 10', 11' includes an opening 14, 14', 15' for receiving an end of a cutting cord. The cut cord 6, 6' is fixed with its cut cord end in the cord holder 10, 10', 11' and subsequently wound onto the cord reel 7. This process is detailed later.

As shown in fig. 4 and 5, the cord holders 10, 10', 11' are configured at a circumferential wall 19 of the cord reel 7. Thus, the wire holders 10, 10', 11' are arranged as close as possible to the rotation axis 4 in order to obtain as little moment of inertia of the wire drum 7 as possible. The first cord holder 10, 10' of the pair 21, 22 is arranged in the first spool chamber 8. The first cord holder 10, 10' rests here against the intermediate wall 17, i.e. against the side of the intermediate wall 17 opposite the first reel wall 16. The second cord holder 11, 11' of the pair 21, 22 is arranged in the second spool chamber 9. The second cord holder 11, 11' is in this case in contact with the intermediate wall 17, i.e. on the side of the intermediate wall 17 opposite the second reel wall 18. In a preferred embodiment, the first cord holder 10, 10 'of one holder pair 21 and the second cord holder 11, 11' of the other holder pair 21 are arranged opposite, in particular mirror-symmetrically, with respect to the intermediate wall 17. The inlet opening 36 and the outlet opening 37 of the through-going cord channel 35, 35' are arranged centrally in the circumferential direction between the two cord holders 10, 10', 11' of the holder pair 21, 22.

As shown in fig. 7 and 8, the diameter a of the openings 14, 15 of the cord holders 10, 11 of the first pair 21 is greater than the diameter b of the openings 14', 15' of the cord holders 10', 11' of the second pair 22. The diameter b of the openings 14', 15' of the cord holders 10', 11' of the second pair 22 is at most 90% of the diameter a of the openings 14, 15 of the cord holders 10, 11 of the first pair 21. The diameter b of the opening of the cord holders 10, 11 of the second holder pair is at least 60% of the diameter a of the openings 14, 15 of the cord holders 10, 11 of the first holder pair. The different diameters a, b of the openings 14, 14', 15' of the pairs 21, 22 of holders enable the use of cutting cords 6, 6' having different diameters. It is thus possible to retain the cutting cord 6, 6 'with the larger diameter a of the opening 14, 15 in the pair of holders 21 with the opening 10, 11 and the cutting cord 6, 6' with the smaller diameter b of the opening 14', 15' in the pair of holders 22 with the opening 10', 11'.

As shown in fig. 8, the openings 14, 14', 15' of the cord retainers 10, 10', 11' of each retainer pair 21, 22 have an angular interval a of 150 ° to 210 °, in particular 160 ° to 200 °, about 180 °, measured about the axis of rotation 4. In a preferred embodiment, the cord holders 10, 10', 11' of at least one of the holder pairs 21, 22 are at least partially located in a longitudinal plane 5 containing the rotation axis 4. Due to the offset arrangement of the first and second cord holders 10, 11, 10', 11' of each holder pair 21, 22 in the circumferential direction of the axis of rotation 4, the ends of the cutting cords 6, 6' are likewise clamped in the cord holders 10, 10', 11' offset from one another at corresponding angular intervals. The cord openings 47 at the housing 44 have an angular separation of about 180. The cutting cords thus exit the housing 44 offset from each other at an angular spacing of approximately 180. Due to the offset thread holders 10, 10', 11' and the offset thread opening 47, a symmetrical winding of the cutting threads 6, 6' is possible and thus also a uniform mass distribution about the axis of rotation 4 is possible. Thus, the centrifugal forces acting on the cutting cords 6, 6' during operation of the cord harvesting head 3 cancel each other out. An imbalance of the cord reel 7 and thus also of the cord harvesting head 3 is avoided thereby.

As shown in particular in fig. 7, the cord retainers 10, 10', 11' of at least one retainer pair 21, 22 are formed by cord chambers 12, 13 of the same type. The cord chambers 12, 13 are accessible via the openings 14, 14', 15' of the cord holders 10, 10', 11'. The openings 14, 14', 15' are formed at the front side of the cable chambers 12, 13 in the direction of rotation 20. At the side of the cord chambers 12, 13 located at the rear in the direction of rotation 20, a stop 23 for cutting the cord end is formed. In order to clip the cutting cord 6, 6' into the cord holder 10, 10', 11', the cutting cord 6 may be inserted into the cord cavity 12, 13 via the opening 14, 14', 15' of the cord holder 10, 10', 11' until the stop 23 is pushed into the cord holder 10, 10', 11 '. In a preferred embodiment, the cutting cord 6, 6' may be inserted into the cord cavity 12, 13 only via the opening 14, 14', 15' of the cord holder 10, 10', 11 '. It may be provided that a further opening is provided at the side of the cord chambers 12, 13 which is located at the rear in the direction of rotation 20, which opening is merely used for cleaning the cord holders. The diameter of the opening is configured to be so small that the cutting cords 6, 6' still stop at the stop 23. The cutting cords 6, 6' cannot be inserted through the opening provided at the stop 23. In a preferred embodiment of the cord reel 7, as shown in fig. 8, the cord chambers 12, 13 are closed at their sides opposite the openings 14, 14', 15' (i.e. at the stop 23).

As shown in fig. 5, in a preferred embodiment, stiffening ribs 67 are provided at the circumferential wall 19 between the first cord holder 10, 10 'and the first drum wall 16 and between the second cord holder 11, 11' and the second drum wall 18. The cutting cords 6, 6' are placed above the stiffening ribs 67 during winding. The force acting on the cord reel 7 by cutting the cords 6, 6' is mechanically preferentially distributed to the circumferential wall 19 by the stiffening ribs 67, so that peak loads at the circumferential wall 19 of the cord reel 7 are avoided. In an alternative embodiment of the rope drum 7 according to the invention according to fig. 11, a stiffening wall 68 may be provided instead of the stiffening rib 67. The reinforcing wall 68 extends in the direction of the axis of rotation 4 from the first cord holder 10, 10' to the first drum wall 16. Here, the reinforcing wall 68 is part of the cord holder 10, 10', whereby the reinforcing wall 68 extends completely from the intermediate wall 17 to the first bobbin wall 16. In the same embodiment, a further reinforcing wall 68 is provided which extends in the direction of the axis of rotation 4 from the second cord holder 11, 11' to the second reel wall 18. Preferably, the reinforcing wall 68 extends over the entire length c of the cord chambers 12, 13.

The user can choose between two possible solutions for winding the cutting cords 6, 6'. If the cord harvesting head 3 is detached, the user may insert the first cutting cord 6 into the first cord holder 10, 10' of the pair of holders 21, 22 and the second cutting cord 6' into the second cord holder 11, 11' of the same pair of holders 21, 22. The wire drum 7 can then be caused to rotate in a winding direction 24 opposite to the unwinding direction. Here, the cutting cords 6, 6' can be held by hand in such a way that they are wound onto the cord reel 7. The cutting cord 6, 6' is bent approximately 180 ° from the cord holder 10, 10', 11', thereby holding the cutting cord end clamped in the cord holder 10, 10', 11 '. The cord reel 7 can then be placed into the cord cutting head 3 with the cutting cords 6, 6 'wound in the first and second reel chambers 8, 9 such that the free ends of the cutting cords 6, 6' protrude from the cord opening 47 of the housing 44 of the cord cutting head 3.

If the user does not want to remove the cord harvesting head 3, he can guide the cutting cord 6, 6 'from the outside through the cord channels 35, 35' and subsequently rotate the cord reel 7 in the winding direction 24 relative to the housing 44. In this case, the cable drum 7 is unwound on the rear side 53 of the ramp 51 at the counter contour 50 and is moved away from the housing 44 in the direction of the axis of rotation 4 against the spring force of the spring element 49 until the ramp 51 snaps into the corresponding counter contour 50. There is no need to apply a pulling force at the handling device 32 of the rope reel 7, as is required for unwinding. It is sufficient to rotate the wire drum 7 in the winding direction relative to the housing 44, since the shape of the ramp 51 automatically leads to an overriding of the geometry of the counter contour 50. This operating principle is also known in ratchet devices. The cord channel 35, 35 'thus forms an alternative securing possibility in view of the cord holders 10, 10', 11 'for securing the cutting cord 6, 6' in the drum chamber 8, 9.

In fig. 10 is shown another cord reel 7 according to the invention, which differs from the embodiment according to fig. 5 only in the arrangement of the cord holders 10, 10', 11'. The cord holders 10, 10', 11' are arranged in the intermediate wall 17 of the cord reel 7. Here, the first cord holder 10, 10 'is arranged adjacent to the inlet opening 36 of the cord channel 35, while the second cord holder 11, 11' is arranged adjacent to the outlet opening 37 of the cord channel 35. Preferably, the wire holders 10, 10', 11' are mutually configured such that the wire holders 10, 11 of the first pair 21 are configured non-axisymmetrically with respect to the rotation axis 4 and the wire holders 10', 11' of the second pair 22 are likewise configured non-axisymmetrically with respect to the rotation axis 4. Here, the longitudinal direction of the cord holders 10, 10', 11' intersects the circumferential wall 19. The same way of operation and the same advantages according to the invention as for the wire drum 7 according to fig. 5 are thereby obtained for the wire drum 7 according to fig. 10.