REEL WITH ACCOMMODATION THAT HAS TRIANGULAR OPENING FOR ENTRY OF LINEAR MATERIAL
PRIORITY CLAIMING This application claims priority under 35
U.S.C. §119 (e) for Provisional Patent Application No. 60 / 775,629, filed on February 21, 2006. INCORPORATION THROUGH REFERENCE The present application incorporates by reference, the complete description of the Patent Application Publication of E.U. No. US 2006-0266605 Al. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to reels for winding and unwinding linear material and specifically to apparatuses and methods for improving the uniformity of the rolled material and facilitating unwinding. Description of Related Art A spool typically comprises a cylindrical spool drum on which a flexible linear material (such as cord, hose, etc.) is wound. The drum, usually rotates about a central axis for winding and unwinding (also referred to herein as "winding" and "unwinding") the linear material with respect to
the cylindrical surface of the drum. Some reels include housings that protect the drum and wind the linear material from the environment. The housing may include an inlet or opening through which the linear material extends, so that it may be withdrawn from the housing or subsequently retracted back into the housing. The drum rotation can be motorized or manual, such as by a crank or other similar device. Some spool housings have a portion that includes the opening for the linear material and moves with respect to the rest of the housing, thereby allowing the user to change the position from which the linear material is drawn from the spool. For example, the U.S. Patent. No. 6, 279, 848 to Mead discloses a cylindrical spool drum that rotates about a horizontal axis and is enclosed within a spherical housing comprising upper and lower hemispherical skin portions. The upper coating portion includes a guide opening for the wound linear material and is attached to the drum. The upper coating portion and the drum rotate together about the vertical central axis with respect to the lower coating portion. This allows a user to extract the linear material from the housing through the guide opening and move it around the reel with the guide opening
following the radial position of the user. The upper coating portion and the drum form a unit that is freely rotated (about the vertical axis) with respect to the lower coating portion, through 360 ° and more. Another example of a reel housing having a portion that includes an opening of the linear material and moving with respect to the remainder of the housing is shown and described in the U.S. Patent Application Publication. No. US 2006-0266605 Al. That reference discloses a spherical spool housing comprising lower, intermediate and upper housing portions, a fixed internal vertical shaft member with respect to the lower and upper housing portions and a drum rotatable on the shaft member and surrounded by the intermediate housing portion. In that reference, the intermediate housing portion includes a linear material opening and is also rotatable, independently of the drum, around the shaft member. A variety of reels, particularly non-motorized reels, include spring return mechanisms to automatically wind the linear material. Typically, a coil of steel material for a flat spring is provided with one end secured to the reel drum and the other end secured to an axis on which the drum rotates. For example, the U.S. Patent. Do not.
6,273,354 to Kovacik et al., Describes such a spool. Such spools are often provided with a ratchet and finger mechanism (or similar apparatus) to allow the user to initiate the re-winding of the spool by a slight pull on the linear material. SUMMARY OF THE INVENTION In one aspect, the present invention provides a reel comprising a drum and a housing substantially enclosing the drum. The drum has a coil surface on which a linear material can be wound, the coil surface having two ends. The drum is rotatable about a drum axis relative to at least a portion of the housing. The at least one portion of the housing generally has a triangular opening sized to receive a linear material wound on the drum. The opening has a first side oriented generally parallel to the drum axis and second and third sides which are at a vertex generally equidistant between the opposite ends of the bobbin surface of the drum. In another aspect, the present invention provides a method comprising rotating a drum around a drum shaft to wind a linear material over the drum's bobbin surface or unwinding the linear material from the drum's bobbin surface. During the
With the drum turning stage, the linear material is withdrawn through a generally triangular opening in a housing substantially enclosing the drum, the drum being rotatable about the drum axis with respect to a portion of the housing including the opening. The opening has a first side oriented generally parallel to the axis of the drum and second and third sides which are at a vertex generally equidistant between the opposite ends of the bobbin surface of the drum. In another aspect, the present invention provides a reel comprising a drum and a housing substantially enclosing the drum. The drum has a bobbin surface on which a linear material can be wound and rotated about a drum axis in relation to at least a portion of the housing. The at least one portion of the housing generally has a triangular opening sized to receive a linear material wound on the drum. In another aspect, the present invention provides a method comprising rotating a drum around a drum shaft to wind a linear material on a drum coil surface or unwinding the linear material from the drum's bobbin surface. During the drum turning stage, the linear material is extracted through a generally triangular opening in a
housing substantially enclosing the drum, the drum being rotatable about the drum axle with respect to a portion of the housing including the opening. For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above and as further described below. Of course, it should be understood that not necessarily all the objectives or advantages can be achieved in accordance with any particular embodiment of the invention. Thus, for example, the person skilled in the art will recognize that the invention may be incorporated or carried out in a way that achieves or optimizes an advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or be suggested in the present. All these modalities are proposed to be within the scope of the invention described herein. These and other embodiments of the present invention will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the appended figures, the invention not being limited to any one or more mode (s). ) particular preferred (s) described (s). BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a
reel according to one embodiment of the present invention. Figure 2 is an exploded top perspective view of the reel of Figure 1. Figure 3 is a bottom exploded perspective view of the reel of Figure 1. Figure 4 is a top perspective view of the reel of Figure 1, with the upper housing portion separated. Figure 5 is a bottom perspective view of the reel drum of Figure 1. Figure 6 is a front view of a triangular opening according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED MODE Overview The embodiments of the present invention provide a reel comprising a reel drum substantially enclosed within a housing having a portion with a triangular opening for receiving and guiding the linear material on a reel surface of the reel. drum as the drum rotates relative to the housing about a drum axis. In some embodiments, the housing portion having the triangular guide opening is also rotated about the drum axis, relative to the
drum. In some embodiments, the rotatable housing portion having the triangular guide opening is also rotated, about the drum axis with respect to one or more of the other portions of the housing. In other words, the drum and the housing portion with the triangular guide opening are preferably rotated independently of the rest of the housing. In preferred embodiments, the housing portion with the triangular guide opening is freely rotated through at least 360 ° and preferably any fraction or multiple thereof, with respect to the remainder of the housing. In preferred embodiments, the reel is adapted to the coil cord. However, the skilled artisan will appreciate that the reels of the present invention can wind other types of linear materials, such as hoses, ropes and the like. The reels that use a drum that rotates around the vertical axis are susceptible to the problem of uneven rolling. In other words, the linear material wound on the drum tends to form a non-uniform winding. This is because the linear material tends to coil over the lower portion of the drum, due to the effects of gravity. The present inventors discovered that this trend is significantly reduced by a guide to the linear material or housing opening
which is generally located equidistantly between the open ends of the coil surface of the drum. During winding, a guide or opening thus placed causes the linear material to roll more evenly over the bobbin surface. However, when reversing the direction of rotation of the drum, the centrally located guide or opening can substantially prevent or diminish the unwinding process of the linear material, due to the restrictive position and size of the opening relative to the length of the coil . In many cases, the linear material tends to be blocked or immobilized during unwinding. As used herein, the terms "winding" and "winding" refer to the process of rotating the drum in one direction to accumulate the linear material on the drum's bobbin surface and "unwind" and "unwind" refers to the process of retracting the linear material from the drum, which involves turning the drum in the opposite direction. The present invention addresses this problem by providing a spool having a housing with generally a triangular guide opening for the linear material. A first vertex of the triangular opening is preferably generally located equidistantly between the ends of the bobbin surface of the drum. The first vertex points in the direction in which the linear material of
so that during rolling, the linear material tends to slide against the first vertex. Thus, during winding, the linear material is guided on the drum from a generally equidistant position between the opposite ends of the spool surface, advantageously producing a more regular and uniform winding as explained above. The side of the triangular opening that is opposite the first vertex is preferably oriented substantially parallel to the axis of rotation of the drum and has a length preferably large enough to significantly improve the ease of unwinding. During unwinding, the linear material is free to slide against the total length of this side of the triangle, advantageously reducing the likelihood that the linear material will be immobilized. Exemplary Reel In order to provide a more complete understanding of the invention, the following paragraphs describe an exemplary reel and a reel housing that are particularly suitable for having a triangular opening as taught herein. Although the reel 10 illustrated is an electric cord spool, the triangular openings of the invention can be provided for reels adapted to wind different types of linear materials. Details
Additional reel 10 illustrated are shown and described in the U.S. Patent Application Publication. No. US 2006-0266605 Al. Figure 1 shows a reel 10 comprising a housing 11 enclosing a rotatable reel drum 20 (Figures 2, 3 and 5) on which a flexible linear material 2 can be wound. illustrated, the linear material 2 comprises an electrical cord with a female plug connector 3 as is known in the art. The housing 11 comprises a first or lower housing portion 12, a second or upper housing portion 14 and an intermediate housing portion 16 interposed therebetween. In the illustrated embodiment, the housing portions 12, 14 and 16 collectively form a substantially spherical shape. However, the housing 11 can have other shapes, giving due consideration to the objective of substantially substantially enclosing and preferably enclosing the drum 20. The reel 10 also includes a first or lower supporting structure 18 installed to the lower housing portion 12 , as well as a second or upper support structure 19 installed to the upper housing portion 14. The lower support structure 18 is configured to support the reel 10 on a lower support surface. In a preferred embodiment, the reel is capable of operating in reverse and the
upper support structure 19 is also configured to support the spool 10 on a lower support surface. As explained in more detail below, the middle housing portion 16 includes a triangular opening 15 through which the linear material 2 can extend. As mentioned above, in a preferred embodiment the spool 10 is adapted to wind the electric cord 2. Preferably, the reel 10 provides electrical power to the cord 2 from an external electrical power outlet. In the embodiment of Figure 1, the spool 10 includes an electrical cable 13 extending out of a lower opening (not shown) of the lower housing portion 12. The cable 13 preferably includes a standard electric plug 17 that is adapted to the plug into a standard electrical power outlet. The cable 13 preferably provides power to the electrical cord 2 wound on the spool 10. Although the illustrated connectors 3 and 17 are male and female respectively, these "genres" can be reversed. Figures 2 and 3 respectively, are top and bottom views respectively cut away from the reel 10. The reel 10 includes a shaft member 22 having a first end 24 and a second end 26 (Figure 4). The first end 24 is connected and preferably integrally formed with the lower housing portion 12. In
this embodiment, the shaft member 22 is configured to extend through an opening 28 (Figure 5) in the drum 20 so that the drum is rotated about the vertical axis 31 (also referred to herein as a "drum shaft"). ") defined by the shaft member 22. Preferably, the opening 28 is dimensioned to tightly receive the shaft member 22. The shaft member 22 is also configured to extend through an opening 30 (FIG. 4) of the half housing portion 16. Preferably, the opening 30 is dimensioned to tightly receive the shaft member 22. In one embodiment, the shaft member 22 has a larger diameter lower portion for a tight fit with the opening 28 of the drum 20 and a smaller upper diameter portion for a tight fit with the opening 30 of the middle housing portion 16, it being understood that the opening 28 is larger than the opening 30. In another embodiment, the openings 28 and 30 are approximately the same size and the shaft member 22 has a substantially uniform diameter. The experts will appreciate that other configurations of the shaft member 22 and the openings 28 and 30 are possible, keeping in mind the objective of allowing both the middle housing portion 16 and the drum 20 to rotate with respect to the shaft member 22 and independently with respect to each other. With reference to Figures 2-4, the portion of
The upper housing 14 is preferably adapted to connect the second end 26 of the shaft member 22 when the member 22 extends through the drum 20. Preferably the upper housing potion 14 and the shaft member 22 are removably secured from each other to so they can not turn with respect to each other. In the illustrated embodiment, the upper housing portion 14 includes four through holes 32 sized and configured to receive the screws 34 (Figure 4) which are in turn adapted to be screwed into the threaded holes 36 in the second end 26 of the housing member. shaft 22. It will be appreciated by those skilled in the art that any of a wide variety of means may be employed to removably secure the upper housing portion 14 to the shaft member 22. The reel 10 thus allows the middle housing portion 16 and the drum 20 to rotate. freely around the shaft member 22 and independently with respect to each other. In order to assist or facilitate the rotation of the drum 20 and / or the middle housing portion 16, the turning aid elements such as ball bearings, rollers and the like (but not necessarily) can be provided at the interfaces between the portions of accommodation 12 and 16, between the housing portions 14 and 16, between the middle housing portion 16 and the drum 20,
between the lower housing portion 12 and the drum 20, between the shaft member 22 and the drum 20 and / or between the shaft member 22 and the middle housing portion 16. Also the rail or other guide means can be provided for control the relative movement of these members. Lubricants can also be used to reduce friction in these interfaces. With continued reference to Figures 2 and 3, each of the upper and lower housing portions 12 and 14 preferably includes an annular wall 39 and a plurality of radial projections 37 for adding strength. Alternative configurations for the internal walls and the projections are also possible, keeping in mind the objective of improving the strength and rigidity of the housing portions 12, 14. In other embodiments, the housing portions 12 and 14 have none of the internal members to add resistance. In the embodiments described, the upper and lower support structures 18 and 19 are (but not necessarily) substantially similar. Accordingly, only the lower support structure 18 is described in detail herein. With reference to Figures 2 and 3, the lower support structure 18 preferably comprises two mounting portions 40 and two handle portions 38. The mounting portions 40 illustrated comprise
elongated tubular members that are configured to be installed on opposite sides of the lower housing portion 12. The experts will appreciate that the mounting portions 40 may alternatively have non-tubular shapes. In a preferred embodiment, the lower housing portion 12 includes cavities 42 that are dimensioned and shaped to receive the mounting portions 40. The mounting portions 40 can be secured
(preferably removably) to the lower housing portion 12 by any of a wide variety of means such as by combinations of screws, nuts and bolts and the like. For example, the illustrated mounting portions 40 include internally threaded vertical projections 41 that fit snugly in the corresponding cavities 43 within the cavities 42. The cavities 43 are configured to receive the screws to create a removable connection between the mounting portions 40. and the lower housing portion 12. The mounting portions 40 may be curved to conform more closely to the hemispherical shape of the lower housing portion 12, providing a more stable and secure connection. The illustrated handle portions 38 are generally positioned on opposite sides of the lower housing portion 12 and are substantially parallel to each other.
yes. In the illustrated embodiment, the handle portions 38 comprise elongate tubular members oriented generally perpendicular to the shaft member 22 and positioned so as to maintain a lower end of the lower housing portion 12 at least slightly above the lower support surface. The handle portions 38 are sized and shaped preferably to allow a person to hold it directly with their hands. Each mounting portion 40 preferably has one end coupled to one end of one of the handle portions 38 and the other end coupled to one end of the other of the handle portions 38. Each end of the handle portions 38 is a. copla preferably to only one of the mounting portions 40. The end portions of the illustrated mounting portions 40 extend downwardly and outwardly from the central portion that installs the cavities 42 of the lower housing portion 12. In an embodiment Preferred, the lower support structure 18 further comprises four coupling members 44, each of which engages one of the ends of one of the handle portions 38 at one end of one of the mounting portions 40. In the illustrated embodiment, the coupling members 44 contact the lower support surface, while the handle portions 38 and the mounting portions 40 do not.
make. Coupling members 44 illustrated comprise elbow-shaped tubular members. As mentioned above, the upper support structure 19 is preferably substantially similar to the lower support structure 18. Accordingly, the support structure 19 illustrated preferably includes handle portions 38, mounting portions 40 adapted to be installed within the cavities 42 of the upper housing portion 14 and the coupling members 44 substantially described above. The handle portions 38 of either of the support structure 18, 18 can be advantageously used to conveniently grip and move the spool 10. Preferably, the support structures 18, 19 are configured to prevent the housing 11 (eg, the portions of housing 12, 14 and 16) makes contact with a generally flat bearing surface with respect to the orientation of the spool 10. For example, the support structures 18, 19 illustrated prevent the housing 11 from contacting the ground even if the spool 10 turns on its side. In this configuration, the support structures more effectively protect the housing 11. In other embodiments, the upper support structure 19 is configured differently or can still be omitted from the reel 10. It will be appreciated that a wide variety of different types
support structures 18, 19 without departing from the scope of the invention. Figures 2, 3 and 5 show a preferred embodiment of the reel drum 20. The drum 20 illustrated comprises a substantially cylindrical member 46 having a coil surface 47 on which the linear material can be wound, a first end plate 48 at one end of the member 46 and a second end plate 50 at the other end of the member 46. member 46. The cylindrical member 46 and the end plates 48 and 50 preferably preferably rotate together in unison about the shaft member 22. The cylindrical member 46 and the end plates 48 and 50 may be integrally formed as a single unit part. or they can be formed separately and secured together. The middle housing portion 16 surrounds the drum 20 and preferably rotates around the shaft member 22 independently of the drum 20. The triangular opening 15 is preferably positioned close to the surface of a cylindrical member 46, in order to direct the linear material over the drum 20 during winding. With reference to Figures 3 and 5, the lower housing portion 12 is preferably adapted to house a motor 51 which drives the reel drum 20 through a gear reduction installation. In the illustrated embodiment, the motor 51 is housed within the shaft member 22.
The motor 51 is inserted into an opening 52 in the lower side of the lower housing portion 12. A motor cover 54 can be provided to support the motor 51 and / or close and possibly seal the opening 52 to protect the motor and the gears of dust and dirt. For ease of illustration, gear reduction is not shown in the drawings. However, it will be understood by those skilled in the art that the gear reduction may comprise any suitable number of gears assembled to cover the rotational output of the motor to the rotation of the drum 20 about the drum axis. For example, as shown in Figures 3 and 5 the gear reduction can affect the rotation of the drum 20 by turning a ring gear 58 comprising an annular wall. In the illustrated embodiment, the annular wall is part of a ring-shaped part 70 that is secured to the underside of the end plate 48. Additional details of a preferred configuration of the gear reduction are set forth in the Application Publication. US Patent No. US 2006-0266605 Al. Thus, the motor 51 produces the rotation of the drum 20 around the shaft member 22. As seen in Figure 3, in the preferred embodiment the motor 51 is upside down (ie, its face comes down). However, it will be appreciated that the motor 51 is oriented differently as shown. The experts will also understand that you can
a wide variety of different types of motors and gear reduction installations are employed without departing from the scope of the invention. In use, a user can unwind the linear material 2 from the drum 20 by removing the linear material through the triangular opening 15 of the middle housing portion 16. By doing so, the drum 20 starts to rotate with respect to the housing portions upper and lower 12, 14 and the shaft member 22. The middle housing portion 16 is also freely rotated and its rotational position may vary because the opening 15 tends to follow the radial direction in which the user removes the linear material 2. As the user moves around the reel 10 holding a portion of the linear material that is pulled out of the housing 11, the middle housing portion 16 rotates freely to let the opening 15 follow the radial direction of the linear material removed. In this form, the freely rotating half housing portion 16 facilitates the use of the linear material within a larger area. For example, the reel 10 can be centrally positioned within a room or exterior area (e.g., on the floor or installed on a roof) and the linear material can be relatively easily removed to any direction or portion of the room or area. When the user wishes to wind the linear material on the drum 20, accordingly, the
The user can turn on the motor 51. The resulting rotation of the drum 20 causes the linear material to retract towards the housing 11 through the opening 15 of the middle housing portion 16. During winding, the middle housing portion 16 can tend to rotate together with the drum 20 due to the friction between them. This can cause the linear material to spin around the spool 10, which can result in damaging the persons and objects that surround it. Preferably, the spool 10 includes a mechanical and / or electrical mechanism for rotationally securing the middle housing portion 16 with respect to the upper and lower housing portions 12, 14 during winding. With reference to Figure 3, the illustrated embodiment includes a solenoid device 62 secured to the lower housing portion 12. The solenoid device 62 is electrically operable, as is well known in the art to cause a piston rod 64 to extend in u out of an outer opening of its housing. The shank 64 is dimensioned and shaped to slide towards either of an indentation ring 66 provided on the inner surface of the middle housing portion 16. The indentations 66 can have any of the wide variety of shapes and sizes, keeping in mind the objective to allow the solenoid stem 64 to stop the
half housing portion 16 to rotate as one of the indentations 66 enters. When the stem 64 enters one of the indentations 66, it "secures" the middle housing portion 16. In other words, the extended stem 64 prevents the portion of middle housing 16 rotates with respect to the upper and lower housing portions 12, 14. An electronic control system can be provided to activate the solenoid device 62 (ie, cause the rod 64 to extend) when the motor 51 is turned on to a winding operation and retracting the solenoid device 61 (ie, causing the rod 64 to retract toward its housing) when the motor 51 is turned off or for an energized unwinding operation. In a preferred embodiment, the electric cord reel 10 is adapted to provide electrical power to an electrical cord 2 wound on the drum 20, the cord 2 is operable to supply power to an external device. Accordingly, the reel 10 may include suitable means for facilitating an energy connection between the cord 13 (Figure 1) and the cord 2 wound as known in the art. For example, the lower part of the end plate 48 of the drum 20 may include electrically conductive rings 78 (Figure 5), also referred to as "slip rings" adapted to contact the electric brushes (not shown) which in turn are find
in electrical communication with the cord 13. Furthermore, the drum 20 can be configured to provide an electrical connection between the slip rings 78 and an energy connector (not shown) on the drum 20, to which the cord 2 is connected. A preferred configuration for providing electrical power to the wound cord 2 is provided in Patent Application Publication No. US 2006-0266605 Al. Triangular Opening Figure 6 shows the triangular opening 15, in accordance with a preferred embodiment of the invention. As mentioned above, the middle housing portion 16 includes a generally triangular opening 15 dimensioned to receive a linear material (in the illustrated embodiment, the electrical cord 2) wound on the drum 20. The opening 15 has a first side 92, a second side 94 and a third side 96. The first side 92 is preferably oriented generally parallel to the axis 31 of the drum (Figure 2). The first side 92 and the second side 94 meeting at a vertex 97. The first side 92 and the third side 96 meeting at the vertex 95. The second side 94 and the third side 96 meeting at the apex 93. The vertex 93 is placed preferably positioned generally equidistantly between the opposite ends of the coil surface 47 of the drum 20. For example, in the
illustrated, the vertex 93 is preferably positioned generally equidistant between the inner surfaces of the end plates 48 and 50. The opening 15 is dimensioned and oriented advantageously so that, during winding, the linear material 2 tends to move against the vertex 93. Preferably, a securing apparatus or mechanism (such as the solenoid device 62 described above) is provided to positionally secure the middle housing portion 16 while the linear material 2 is wound onto the drum 20, so as to that the vertex 93 remains fixed with respect to the rotating drum. During unwinding of the linear material 2, the middle housing portion 16 is preferably unlocked with respect to the housing portions 12, 14, allowing the housing portion 16 to rotate in a direction that can facilitate retraction of the linear material. As a result, the linear material 2 is free to retract through a portion of the opening 15 other than just the apex 93 (in Figure 6, any portion of the opening 15 to the right of the vertex 93). Advantageously, a larger vertical dimension of the opening 15 is available to retract the linear material 2, resulting in significant improvements in the ease of retraction of the material
linear. Also, the new triangular shape of the opening 15 is left so that a greater amount of the linear material is wound in the housing 11, such as an increase of approximately 25%. In a preferred embodiment, the vertices 93, 95 and
97 are rounded, with a radius preferably equal to or greater than that of linear material 2. Such rounded corners are preferred to acute corners because the latter may involve higher concentrations of tension in the middle housing portion 16. Also, the thickness of the middle housing portion 16 is preferably increased along the edges or sides 92, 94, 96 of the opening 15, to provide increased resistance to withstand loads imposed against such edges when displaying the linear material 2 during winding and unwinding. The experts will appreciate that the ease with which the linear material 2 of the reel 10 can be unrolled depends on the length of the first side 92 of the triangular opening 15 relative to the length of the drum 20. The first side 92 extends through preferably of at least 35%, more preferably at least 50%, more preferably at least 60%, more preferably at least 80% and even more preferably at least 95% of a length of the coil surface 47 of the drum 20. It will be appreciated that the ease with which the material can be unwound
linear depends on the extent to which the first side 92 of the triangular opening 15 is centered with respect to the length of the drum 20. In this respect, a distance and between (1) a plane 102 that is parallel to the axis of the drum 31 (Figure 1) and extending through a center 98 of the first side 92 and (2) a plane 104 which is perpendicular to the axis 31 of the drum and which extends through a center of a surface length of coil 47 of the drum 20, is preferably less than 20%, more preferably less than 10% and even more preferably less than 5% of the length of the coil surface. In the illustrated embodiment of Figure 6, the plane 104 is below the center 98 of the length of the first side 92 of the opening 15; however, it will be appreciated that the plane 104 may be above or directly at level with the center 98. The experts will understand that the advantages of providing the triangular opening 15 are achieved when the opening "points" in the correct direction. In particular, the linear material 2 is preferably wound in a direction in which the apex 93 points. For example, in the orientation of Figure 6, the linear material 2 is preferably wound in a clockwise direction (viewing the reel and opening 15 of Figure 6 from above) around the drum. In other words, the
linear material 2 is preferably wound in one direction so that during winding of the linear material on the drum, the linear material tends to slide against the apex 93. The experts will appreciate that the ease of retraction of the linear material also depends on the shape of the triangular opening 15. In a preferred embodiment, the opening 15 is formed substantially similar to an isosceles triangle and the second side 94 and the third side 96 are oriented with respect to each other at an angle preferably within 20-50 °, more preferably within 25-45 ° and still more preferably within 30-40 °. Other possible ranges include 25-55 °, 30-50 ° and 35-45 °. The experts will also appreciate that the ease of retraction of the linear material also depends on the size of the opening 15 relative to that of the drum 20. The coil surface 47 of the drum 20 is preferably cylindrical and the distance between the apex 93 and the first side 92 it is preferably within 40-300%, more preferably within 60-200%, more preferably within 75-150% and even more preferably within 85-125% of a diameter of the coil surface 47. In one embodiment , the distance between the apex 93 and the first side 92 is approximately the same as the diameter of the coil surface. Other suitable ranges for this angle are 70-
130%, 85-115% and 95-105% of the diameter of the coil surface 47. Although the invention has been described in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends further. beyond the modalities specifically described towards other modalities and / or alternative uses and obvious and equivalent modifications thereof. Accordingly, the invention is not intended to be limited by the specific descriptions of the preferred embodiments herein.