Machine and process for forming fold lines in material and folding the material to form a dart flight

Abstract

A method for forming a dart flight comprising providing an elongate sheet 10 of flight material having a decorated side and an undecorated side. The undecorated side has a layer of adhesive. The sheet

Description

Technical Field The present invention relates to darts, specifically those used in the popular game that involves throwing darts at a target dart board, and more particularly to flights for darts and methods of manufacturing these. Background The game of darts is well known and has existed in one form or another for centuries. It is a highly popular international sport and is televised around the World. The modern version of darts is played by two players taking turns to throw three darts in sequence into a dart board. The front face of the dart board describes a circular scoring zone that is divided into twenty numbered segments around a central bullseye. Points are awarded to each player corresponding to the number of the segment into which each of their thrown darts sticks. Each segment is sub-divided into bands, with a central band awarding triple points and an outermost band awarding double points. Adjacent segments of the board are painted in alternating colours, typically black and white. The adjacent segments and bands are also physically separated from one another by a frame of wire that runs along each boundary therebetween on the front face of the dart board. Each dart is constructed with a point (or tip), a barrel, a stem (or shaft), and a flight. The point is arranged to project forward from the barrel at the front of the dart and is designed to impact and stick into the dart board. The barrel is a substantially cylindrical body typically extending about half to two-thirds of the length of the dart. The stem extends backwards from the barrel and carries the flight at the back of the dart, which serves to stabilise the dart in flight when thrown. Typically, the stem is made of lighter-weight material than the barrel and is threaded at its front end so that it can be screwed into the back end of the barrel to assemble the dart. The threaded connection allows the stem to be unscrewed and detached from the barrel, for example to disassemble the dart for storage in a case or for replacement in the event of the stem breaking. In order to score highly and efficiently, darts players typically attempt to group their three darts as closely as possible on the dart board. If the first dart is well placed, it can act as a guide for subsequent darts, with the flight, stem and barrel of the first dart helping to guide the tip of the next incoming dart into position adjacent the tip of the first dart. The point and barrel of a dart are made of resilient materials. The barrel is typically made from a tungsten alloy to provide the dart with a front-loaded mass distribution with minimum barrel diameter, so as to promote stable flight and permit close grouping of thrown darts. By contrast, the stem is normally made of a lighter-weight polymer material such as nylon or polycarbonate. While the front end of the stem is provided with a thread for connection to the barrel, the back end of the stem is formed with four elongate petals defining a cross-slit between them (when viewed from the rear of the stem) for receiving the flight in the slits and thereby gripping the flight between the petals. The flights are easily exchangeable and allow the players to customise their darts both visually, by selecting flights with a preferred printed design, and in terms of their performance, by selecting flights with a preferred size and shape . Each player typically uses darts with different printed designs on the flights. As much as this may reflect personal preferences, it is also to enable each player's darts to be readily identified and distinguished from each other. Different players have different throwing techniques, including how and where they hold the dart to throw it and the speed and trajectory they impart to the dart. For example, some players have slower, looping shots while others have faster, shallower shots. In either case, the player's throwing technique may induce the dart to spin about its axis in flight, or it may induce little or no spin. The sizes and shapes of the flights affect the flight of the dart and so may suit one player's throwing style better than another. Equally, to achieve the desired close grouping of the darts in the board, and in order to be able to throw the darts accurately and reliably, the darts must perform consistently in flight. Variations and / or defects in the dart flights can cause one dart to behave differently from another, causing a player's aim and consistency to deteriorate. The flights in each set of three darts should therefore be made to a consistent size, shape and finish. During the flight manufacturing process, the design is printed onto a sheet of the flight material. The sheet is fed through a fold line forming station. The sheet of flight material is then folded over on itself along the fold lines to form the wings of the flight, with each wing being a double thickness of the sheet material with the printed design showing on both sides of each wing. The side of the sheet material opposite that printed with the design is formed or coated with adhesive and the opposed portions of this side are pressed together when folded over so as to adhere to each other. The folded material is punched with a cutting die to form the wings into the desired final shape. In order to have a consistent placement of the printed design on each wing and each side of each wing, the printed designs, the fold lines in the sheet, and the cutting die must all be aligned correctly to one another. Summary of the Present Invention The present invention has been made in view of the realisation and recognition by the inventors of the aforementioned problems which may arise in prior art designs. The present invention seeks to alleviate or solve one or more of these problems. According to a first aspect of the present invention, there is provided a method for forming a dart flight comprising: providing an elongate sheet of flight material, the sheet being printed, coated or otherwise provided on one side thereof with a decorative flight design and provided on the opposite, undecorated side with a layer of adhesive; feeding the elongate sheet lengthwise through a fold line forming station to thereby form seven parallel fold lines along the length of the sheet, the fold lines being substantially equally spaced apart across the lateral width of the elongate sheet and defining substantially parallel strips between each pair of adjacent fold lines; further feeding the portion of the elongate sheet provided with fold lines through a folding station to thereby fold the elongate sheet along the fold lines such that the sheet is folded in opposite directions along each adjacent fold line so as to bring together the undecorated sides of adjacent strips to form folded-over strips of double thickness along the length of the sheet, wherein the layer of adhesive causes the undecorated sides of the folded-over strips of double thickness to adhere to each other; and further feeding the folded portion of the elongate sheet into a punching- and / or cutting- station to thereby punch- or cut- out the shape of the wings of a dart flight from the folded-over strips and thereby form a finished dart flight. According to a second aspect of the present invention, there is provided an apparatus for forming a dart flight from an elongate sheet of flight material, the sheet being printed, coated or otherwise provided on one side thereof with a decorative flight design and provided on the opposite, undecorated side with a layer of adhesive, the apparatus comprising: a fold line forming station arranged to form seven parallel perforated or scored fold lines along the length of the sheet as the sheet is fed lengthwise through the fold line forming station, the fold lines being substantially equally spaced apart across the lateral width of the elongate sheet and defining substantially parallel strips between each pair of adjacent fold lines; a folding station arranged to fold the elongate sheet along the fold lines as the portion of the elongate sheet provided with fold lines is further fed through the folding station such that the sheet is folded in opposite directions along each adjacent fold line so as to bring together the undecorated sides of adjacent strips to form folded-over strips of double thickness along the length of the sheet, wherein the adhesive causes the undecorated sides of the folded-over strips of double thickness to adhere to each other; and a punching-and / or cutting- station to punch- or cut- out the shape of the wings of a dart flight from the folded-over strips as the folded portion of the elongate sheet is further fed into the punching- and / or cutting- station to thereby form a finished dart flight Optional and preferred features are mentioned in the detailed description below and recited in the dependent claims. Brief Description of the Drawings To enable a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:- Figure 1 shows a schematic view of an apparatus for forming a dart flight from an elongate sheet of decorated flight material; fold line forming station Figure 2 shows a schematic perspective view of how the elongate sheet is folded from a planar configuration into a cross-shaped configuration as it is fed through a folding station of the apparatus of Figure 1. Detailed Description The invention will now be described with reference to specific embodiments. It is to be understood that the disclosed embodiments are provided in order to demonstrate one or more ways of putting the invention into effect and that they are in no way to be considered as being limiting on the scope of protection, which is defined solely by the appended claims. Throughout the figures, like reference numerals are used to refer to like components. Figure 1 shows a schematic view of an apparatus 100 for forming a dart flight from an elongate sheet 10 of flight material in accordance with the present invention. The dart flights are to be made from a sheet of flight material, which is provided as an elongate sheet 10. The flight material can be provided as stacked or folded sheets. In the present embodiment, the elongate sheet 10 is provided on a roll 110. This allows the elongate sheet 10 to be fed continuously from the roll 110 into the dart flight forming apparatus 100. The elongate sheet 10 is decorated prior to being provided to the dart flight forming apparatus 100 and is provided on the roll 110 as a decorated elongate sheet 10. The elongate sheet is decorated on one side 12, typically by being printed or otherwise coated with decorative design elements such as patterns, images and / or text. As used herein, the term "decorated" refers to such a design being applied to the elongate sheet of flight material. It would also be possible for decorative elements to be incorporated into the material of the elongate sheet directly, in which case it is to be understood that the decorated side of the sheet material is the side which faces outwardly and is visible to the user in use of the dart flight. That is to say, the elongate sheet 10 is printed, coated or otherwise provided on one side 12 thereof with a decorative flight design. The opposed side 14 of the elongate sheet 10, which will be folded upon itself and not visible in the finished dart flight, is provided with a layer of adhesive. Herein, this may be referred to as the undecorated side 14 of the elongate sheet 10, although decoration may in some cases be visible on this side of the elongate sheet 10, also. The adhesive is preferably a heat and / or pressure activated adhesive, which will remain inert while the elongate sheet material is rolled, folded or stacked at normal room temperatures and under storage / transfer conditions, but will form an adhesive bond when activated by the application of heat and / or pressure. In order to smoothly and continuously feed the elongate sheet 10 from the roll 110, the elongate sheet 10 is first passed around a number of tensioning rollers (not shown). These rollers maintain the elongate sheet 10 under tension as it is drawn from the roll 110, ensuring that the elongate sheet 10 can be fed smoothly through the dart flight forming apparatus 100 without folding, kinking, warping or otherwise undesirably deforming. The elongate sheet 10 is then fed lengthwise through a fold line forming station 120. Figure 2 shows a schematic perspective view of the elongate sheet 10 being fed lengthwise through the fold line forming station 120. The fold line forming station 120 includes means for forming parallel fold lines along the length of the elongate sheet 10 as it is fed lengthwise through the fold line forming station 120. The fold lines are formed substantially equally spaced apart across the lateral width of the elongate sheet 10 so as to define substantially parallel strips 124 between each adjacent pair of fold lines (and between the first and last fold lines and the edges of the elongate sheet 10). The fold lines may be applied to the decorated side 12 of the elongate sheet 10, or they may instead be applied to the undecorated side 14 of the elongate sheet 10, or to both sides 12 and 14. In the present embodiment, the fold line forming station 120 includes means such as a scoring roller for forming the fold lines in the elongate sheet 10 as the scoring roller rolls along the decorated surface 12. It will be understood that it is important to maintain alignment between the elements of the decorative flight design provided on the decorated side 12 of the elongate sheet 10 and the fold lines, so that the elements of the decorative flight design are properly positioned within the strips 124, and consequently properly located on the wings of the finished dart flights. In particular, the elongate sheet 10 will never be perfectly straight, whilst the positioning of the decorative elements may also vary out of alignment due to variability in the decorating process, for example as the decorative elements are printed. Nevertheless, such variations tend to be gradual such that periodic alignment correction can normally keep the decorative elements adequately aligned with the fold line forming station 120 on an ongoing basis. The present inventors have identified that the alignment of the elongate sheet 10 with the fold line forming station 120 can be appropriately controlled and maintained by adjusting one or more tensioning rollers (not shown) which are interposed between the roll of sheet material 110 and the fold line forming station 120. This is somewhat counterintuitive, since it relies on a control input on a component not normally considered responsible for controlling alignment, and prior to any processing steps taking place on the elongate sheet 10, in order to control the alignment of decorative elements on the wings of the finished dart flights. This solution also avoids the need for guides or other alignment devices which may, in practice, also interfere with the smooth and proper feeding of the elongate sheet 10 through the fold line forming station 120 and subsequent stations of the dart flight forming apparatus 100. To this end, one of the tensioning rollers may be made adjustable, for controlling alignment of the elongate sheet 10. The tensioning roller may be made adjustable by allowing its position to be changed, for example its lateral position or its vertical position, or by allowing the angular orientation of the tensioning roller to be adjusted, or both. Additionally, or alternatively, the tensioning roller may be made adjustable by altering the amount of tension applied to the elongate sheet 10 as it passes through the tensioning rollers, for example by adjusting a biasing force applied to the tensioning roller. In this connection, it is noted that the term "tensioning rollers" refers to the arrangement of rollers which may be provided as one or more sequential sets of rollers, around which the elongate sheet 10 passes as it travels through the dart flight forming apparatus 100. Frictional interaction with the rollers, coupled with the tortuous pathway they define through the dart flight forming apparatus 100 and each of the stations 120, 140, 150 and 160 of the dart flight forming apparatus 100, places the elongate sheet 10 under tension. This can be actively and / or passively managed by controlling the tension applied by the one or more tensioning rollers. The term "tensioning rollers" should therefore be understood to include those rollers which define the pathway of the elongate sheet 10 through the dart flight forming apparatus 100, including those which actively apply tension to the elongate sheet 10 through the action of biasing means or the like acting on the rollers. To monitor the alignment between the elements of the decorative flight design provided on the decorated side 12 of the elongate sheet 10 and the fold lines, typically the finished dart flights are inspected and the positioning of the decorative elements on the wings of the flight is tracked to identify whether adjustment of the tensioning roller is required to bring the elongate sheet 10 back into alignment. After leaving the fold line forming station 120, the portion of the elongate sheet 10 provided with the fold lines, is further fed into the folding station 140. In the folding station 140, the elongate sheet 10 is folded along the fold lines formed in the fold line forming station 120, in the manner shown in Figure 2. This is achieved by passing the elongate sheet 10 through an appropriate guide or other folding mechanism, so as to fold the elongate sheet 10 in opposite directions along each adjacent fold line, in order to form a cross-shaped folded sheet as indicated in Figure 2. Figure 2 shows how the portion of the planar elongate sheet 10 provided with fold lines is folded into the cross-shaped configuration as it travels (from right to left). Corresponding start and end points of the illustrated section of the elongate sheet 10 are labelled at the side edges of the elongate sheet and on each fold line, i.e., showing the corresponding points in both the unfolded and folded configurations . Specifically, the points Al to II in the unfolded configuration are shown on the righthand side of Figure 2, whilst the corresponding points A2 to 12 are shown in the cross-shaped folded configuration on the lefthand side of Figure 2. Each point A and I represents an end of a lateral side edge of the illustrated section of the elongate sheet 10, whilst the points B to H represent the ends of the fold lines. Folding the elongate sheet 10 in the manner shown in Figure 2 causes the undecorated side of each strip 124 to come into contact with the undecorated side of an adjacent strip 124, so as to form folded-over strips of double thickness along the length of the elongate sheet 10. The two end strips 124 running along each side edge 10 of the elongate sheet are also brought into contact with one another, their respective undecorated sides coming into contact to form a double thickness strip as indicated at the top of the folded configuration on the lefthand side of Figure 2. After being folded into the cross-shaped configuration shown in Figure 2, the folded-over strips of double thickness are subsequently transitioned to a flattened configuration, in which two of the double thickness strips are provided on each side of the elongate web 10 as it is further fed into the next station such as roller 150. The folded-over strips of double thickness adhere to each other on their undecorated sides, forming adhered double thickness strips which correspond to the wings of the finished dart flight. As the decorated flight material is provided on a roll 110, an appropriate adhesive should be used on the undecorated side 14 of the elongate sheet 10 so that it does not adhere to the adjacent surface (i.e., the decorated side 12) of the rolled elongate sheet 10 during storage and / or transport. The folded and adhered portion of the elongate sheet 10 is then further fed into the punching- and / or cutting-station 160 . The punching- and / or cutting-station includes a step-wise feeding mechanism 162 and punch dies 164, arranged to incrementally feed the elongate sheet member 10 by an incremental length corresponding to one flight at a time into the punching location between punch dies 164. The step-wise feeding mechanism 162 serves to hold an incrementally advanced sheet member 10 by the required distance in a step-wise fashion, while absorbing the incoming continuous flow of elongate sheet member 10 at the inlet of the punching- and / or cutting-station 160. In this way, after each incremental advance of the elongate member 10 in the punching- and / or cutting-station 160, a dwell period is created during which the punch dies 164 can be operated (i.e., pressed together) on the elongate sheet member 10 to punch out a dart flight. The elongate sheet member 10 is then incrementally advanced by the step-wise feeding mechanism 162 by the next incremental length corresponding to one further dart flight, before the punch dies 164 are again actuated to punch out the next dart flight. The punched or cut out pieces are finished dart flights that are collected in a punched flights collection station 172 of the sorting station 170, whilst the punched web material of the elongate sheet member 10 is fed into a waste collection station 174 of the sorting station 170. Each dart flight made in this way includes four wings, each wing being formed as a double thickness of two layers of sheet material 10 bonded by adhesive therebetween. The first sheet material layer of each wing extends inwardly to a central axis of the dart flight and extends as a continuous sheet material layer outwardly from the central axis to form the second sheet material layer of an adjacent wing on one side of that wing. The second sheet material layer of that wing extends inwardly to the central axis of the dart flight and extends as a continuous sheet material layer outwardly to form the first sheet material layer of another adjacent wing on the other side of that wing. Many adaptations of the principles and concepts outlined above will be apparent to the skilled person in view of the teaching contained herein. All such variations within the scope of the appended claims and their equivalents as properly assessed are intended to fall within the scope of protection defined by the claims.

Claims

1. A method for forming a dart flight comprising:providing an elongate sheet of flight material, the sheet being printed, coated or otherwise provided on one side thereof with a decorative flight design and provided on the opposite, undecorated side with a layer of adhesive;feeding the elongate sheet lengthwise through a fold line forming station to thereby form seven parallel fold lines along the length of the sheet, the fold lines being substantially equally spaced apart across the lateral width of the elongate sheet and defining substantially parallel strips between each pair of adjacent fold lines;further feeding the portion of the elongate sheet provided with fold lines through a folding station to thereby fold the elongate sheet along the fold lines such that the sheet is folded in opposite directions along each adjacent fold line so as to bring together the undecorated sides of adjacent strips to form folded-over strips of double thickness along the length of the sheet, wherein the layer of adhesive causes the undecorated sides of the folded-over strips of double thickness to adhere to each other; andfurther feeding the folded portion of the elongate sheet into a punching- and / or cutting- station to thereby punch- or cut- out the shape of the wings of a dart flight from the folded-over strips and thereby form a finished dart flight.

2. A method according to Claim 1, wherein the decorated elongate sheet, including the adhesive layer on the undecorated side, is provided on a roll and is fed from the roll into the fold line forming station.

3. A method according to Claim 1 or 2, wherein the elongate sheet is substantially continuously fed through the fold line forming station, the folding station, and the punching- and / or cutting- station to continuously form dart flights from the elongate sheet.

4. A method according to Claim 1, 2 or 3, wherein each dart flight includes four wings, each wing being formed as a double thickness of two layers of sheet material bonded by adhesive therebetween, and wherein the first sheet material layer of each wing extends continuously from a central axis of the dart flight to form the second sheet material layer of an adjacent wing on one side of that wing and the second sheet material layer of that wing extends continuously from the central axis of the dart flight to form the first sheet material layer of another adjacent wing on the other side of that wing.

5. A method according to any preceding claim, further comprising aligning the elongate sheet as it passes lengthwise through the fold line forming station to maintain the fold lines parallel with the length of the sheet, wherein the elongate sheet is aligned by adjusting an amount of tension applied to the elongate sheet by a tensioning roller upstream of the fold line forming station and / or by adjusting a position of the tensioning roller upstream of the fold line forming station.

6. An apparatus for forming a dart flight from an elongate sheet of flight material, the sheet being printed, coated or otherwise provided on one side thereof with a decorative flight design and provided on the opposite, undecorated side with a layer of adhesive, the apparatus comprising:a fold line forming station arranged to form seven parallel perforated or scored fold lines along thelength of the sheet as the sheet is fed lengthwise through the fold line forming station, the fold lines being substantially equally spaced apart across the lateral width of the elongate sheet and defining substantially parallel strips between each pair of adjacent fold lines;a folding station arranged to fold the elongate sheet along the fold lines as the portion of the elongate sheet provided with fold lines is further fed through the folding station such that the sheet is folded in opposite directions along each adjacent fold line so as to bring together the undecorated sides of adjacent strips to form folded-over strips of double thickness along the length of the sheet, wherein the adhesive causes the undecorated sides of the folded-over strips of double thickness to adhere to each other; and a punching- and / or cutting- station to punch- or cut- out the shape of the wings of a dart flight from the folded-over strips as the folded portion of the elongate sheet is further fed into the punching- and / or cutting- station to thereby form a finished dart flight.

7. An apparatus according to Claim 6, the apparatus being arranged to feed the elongate sheet into the fold line forming station from a roll of decorated elongate sheet that includes the adhesive layer on the undecorated side .

8. An apparatus according to Claim 6 or 7, wherein the apparatus is arranged to feed the elongate sheet substantially continuously through the fold line forming station, the folding station, and the punching- and / or cutting- station to continuously form dart flights from the elongate sheet.

9. An apparatus according to Claim 6, 7 or 8, further comprising an adjustable tensioning roller upstream ofthe fold line forming station and arranged to align the elongate sheet as it passes lengthwise through the fold line forming station to maintain the fold lines parallel with the length of the sheet by adjusting an amount of tension applied to the elongate sheet by the tensioning roller and / or by adjusting a position of the tensioning roller .

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