WO2022104420A1

WO2022104420A1 - Compact speargun head

Info

Publication number: WO2022104420A1
Application number: PCT/AU2021/051370
Authority: WO
Inventors: Radwan Alam
Original assignee: Hunt Master Pty Ltd
Priority date: 2020-11-23
Filing date: 2021-11-17
Publication date: 2022-05-27

Abstract

The present invention provides a speargun head for use with inverter-type roller gun configurations. The speargun head including a body adapted for location at an end of a barrel of a speargun, first and second pairs of rollers mounted to laterally opposite sides of the body for redirecting one or more flexible elongated members in an inverter-type speargun configuration. The first pair of rollers have an axis of rotation and the second pair of rollers have another axis of rotation, wherein the axes of rotation of the first and second pair of rollers are vertically spaced apart and longitudinally offset from one another. Thus, the invention facilitates smaller roller diameters which reduces rotation inertia of the rollers and also minimises surface area of contact of each one of the rollers with the flexible elongated member, typically a cable, is minimised to thereby minimise friction therebetween.

Description

COMPACT SPEARGUN HEAD

TECHNICAL FIELD

[001] The present invention relates to spear fishing and, in particular, to spear fishing guns or spearguns far use under water.

BACKGROUND

[002] Spearguns are devices used underwater to hunt fish or other marine animals. A speargun is designed to launch a spear or harpoon to impale the animal. The spear is often tethered to the speargun to ensure retrieval of the spear and any fish that may be impaled on the spear.

[003] Elastic powered spearguns are the most common type of speargun and come in a wide variety of configurations. The common element amongst ail elastic powered spearguns is that the power that is used to propel the spear comes from the potential energy stored in one or more stretched rubber bands.

[004] An elastic powered speargun typically includes a barrel, a stock at one end to which a handle and firing assembly are mounted and a muzzle at the other end. In use, a spear is loaded onto the speargun at the end of the barrel comprising the stock, handle and firing assembly, and one or more rubber bands are stretched and are coupled to the firing assembly and the spear. Operation of the firing assembly releases the one or more rubber bands which releases the potential energy stored in the rubber bands to propels the spear down the barrel and from the muzzle towards a target.

[005] A variety of speargun designs and configurations exist that are optimised for different conditions and applications. Some configurations exhibit greater ease of loading and set up, lower power for shorter range targets and for use with shorter, lighter and smaller gauge spears suited for hunting smaller fish in close to shore or estuarine environments. Other configurations are adapted more challenging conditions, higher power for hunting larger fish or in open water or “blue water’ applications. Such configurations can have the drawback that they are more challenging to use and involve more complex set up.

[006] A conventional speargun configuration includes one or more elongated rubbers passing through one or more rubber apertures passing transversely through a head of the speargun at the distal or muzzle end of the barrel. The free ends of the rubbers are attached to a sling which is configured to couple with the firing assembly and the spear. A drawback with such conventional speargun configurations is that the spear is accelerated along only a proportion of the length of the barrel. These deficiencies can be overcome, to some extent, by increasing the length of the barrel of the speargun or increasing the number of thickness of elongated rubbers. However, such remedies can introduce other drawbacks such as excessive recoil when firing the speargun which affects accuracy and loss of manoeuvrability due to the increased size and bulk of the speargun.

[007] Other speargun configurations exist that include rollers atached to the head of the speargun and that in some configurations include an arrangement of pulleys and cables coupled to the rubbers to overcome some of the abovementioned drawbacks with conventional speargun configurations.

[0Q8] One such configuration commonly referred to as a “roller gun” typically includes a pair of wheels or rollers atached to laterally opposite sides of the head. A pair of rubbers are attached underneath the barrel with one end of each rubber attached to the speargun near the handle assembly and the other ends of the rubbers being coupled together with a sling at muzzle end of the barrel. Loading the roller gun involves drawing the sling back towards the handle assembly, thereby stretching the rubbers around the rollers and coupling the sling to the firing assembly and the spear. An advantage of the roller gun configuration is that the spear is accelerated along the entire length of the barrel to the muzzle.

[009] Another speargun configuration commonly referred to as an “inverter gun” typically includes a pair of wheels or rollers attached to lateraily opposite sides of the head. A two or more rubbers are atached underneath the barrel with one end of each rubber attached to the speargun near the handle assembly and the other ends of the rubbers being coupled together with a pair of cables that extend around the rollers atached to the head. The ends of the cables are coupled together with a sling. Loading the inverter gun involves drawing the sling back towards the handle assembly, thereby pulling the cables around the rollers and stretching the rubbers underneath the barrel along the length thereof, and coupling the sling to the firing assembly and the spear. An advantage of the inverter gun is that the spear is accelerated along the entire length of the barrel to the muzzle and the friction between the rollers and the cables is reduced.

[0010] A drawback with existing roller gun and inverter gun configurations is that significant power losses can occur as a result of friction between rotating rollers and cables and/or elongated rubbers. Power losses can also occur to overcome the rotational inertia of the rollers, Such power losses are critical in spearguns as they reduce speargun accuracy, range and ameliorating them with higher power elongated rubbers or lower barrel lengths introduces other drawbacks such as loss of manoeuvrability, higher recoil and greater difficulty In reloading to name but a few.

[0011] Accordingly, a need exists for a speargun and a speargun head that overcomes one or more of the drawbacks detailed above with existing spearguns.

[0012] Any discussion of background art throughout the specification should in no way be considered as an admission that any of the documents or other material referred to was published, known or forms part of the common general knowledge.

SUMMARY OF THE INVENTION

[0013] In one aspect, the present invention provides a speargun head including: a barrel and a head located at a distal end of the barrel; the head including first and second pairs of rollers mounted to laterally apposite sides of the body for redirecting one or more flexible elongated members in art invertertype speargun configuration, the first pair of rollers having an axis of rotation and the second pair of rollers having an axis of rotation, wherein the axes of rotation of the first and second pair of rollers are vertically spaced apart and longitudinally offset from one another.

[0014] In embodiments, the rollers mounted to each side of the head respectively comprise a tandem, wherein the rollers of each tandem include respective circumferential channels that are longitudinally aligned with one another for supporting and redirecting a flexible elongated member

[0015] Preferably, the axes of rotation of the first and second pairs of rollers extend transversely and laterally through the body In embodiments, the rollers on each side of the head operate in tandem to redirect a cable from a rubber member located underneath the barrel of the speargun to the firing assembly and spear located above the barrel of the speargun.

[0016] Embodiments of the invention are advantageous, particularly in invertertype roller gun configurations, in that the speargun head includes rollers that operate in tandem to redirect flexible elongated members, typically cables, extending from the elongated rubber members to a sling at the distal end of the barrel. Furthermore, embodiments of the speargun head enable the use of relatively small diameter rollers to redirect the cables and to bridge the distance between the level of the botom of the head, at which the cables extend from the rubbers, and the level of the top of the head, at which the cables extend to the firing assembly and the spear. Accordingly, embodiments of the invention can be advantageous in that they include smaller rollers to thereby enable a reduction of the rotational inertia of each of the rollers. Thus, the surface area of contact of each one of the rollers with the cable is minimised to thereby minimise friction therebetween.

[0017] Embodiments of the invention can reduce power losses resulting from friction between rotating rollers and cables and/or elongated rubbers. Also, reductions in power losses can be achieved due to a reduction in the rotational inertia of the rollers. Embodiments of the invention that minimise power losses can enable other benefits such as the use of shorter barrel lengths, fewer or smaller diameter or less powerful rubber members, whilst maintaining speargun accuracy, range and manoeuvrability. Other benefits that may be achieved by the reductions in power loss achieved by embodiments of the invention include reductions in recoil and greater ease of reloading.

[0018] In embodiments, the circumferential channels of the rollers of each tandem respectively contact the flexible elongated memberthrough an angular displacement of less than 180 degrees.

[0019] In embodiments, the circumferential channel of a first one of the rollers of each tandem contacts the flexible elongated member through an angular displacement of more than 90 degrees and the circumferential channel of the second one of the rollers contacts the flexible elongated member through an angular displacement of less than 90 degrees.

[0020] In embodiments, the axis of rotation of the first one of the rollers is vertically above and longitudinally forward of the axis of rotation of the second one of the rollers.

[0021] In embodiments, the axes of rotation of the first and second pair of rollers are angularly offset from one another in a plane extending longitudinally and vertically by between 0 degrees and 90 degrees, and preferably between about 5 degrees and 15 degrees.

[0022] In embodiments, the rollers have a diameter of between about 5 and 15 millimetres and preferably between about 7 and 10 millimetres.

[0023] in embodiments, the circumferential channel of a first one of the rollers of each tandem contacts the flexible elongated member at about the level of the top of the body and the circumferential channel of the second one of the rollers contacts the flexible elongated member at about the level of the botom of the body. [0024] In embodiments, the circumferential channels of the rollers are radiused.

[0025] in embodiments, the body includes recesses in laterally apposite sides of the body, each recess configured to receive the rollers mounted to a side of the head comprising a tandem.

[0028] In embodiments, the recess includes a wall extending in a vertical and forwardly sloping direction, thereby defining between the wall and the tandem of the rollers in the recess a passage for receiving and guiding a cable therewithin.

[0027] In embodiments, the passage is configured to permit insertion of a cable therewithin from the bottom or the top of the body and to prevent movement of the cable laterally out of the passage.

[0028] In embodiments, the axis of rotation of the first and second pair of rollers is between about 10 to 15 millimetres from a base of the connection means abutting with the end of the speargun barrel.

[0029] In embodiments, the axis of rotation of the first pair of rollers is about 13 millimetres and the axis of rotation of the second pair of rollers is about 11 ,5 millimetres from the base of the connection means abutting with the end of the speargun barrel.

[0030] In embodiments, the body includes a longitudinal channel extending along the top of the body for guiding a spear during launch,

[0031] In embodiments, the body includes a pair of wing members extending laterally outwards from the body at a distal end thereof, wherein each wing member includes a U-shaped and forwardly open notch for receiving a tether cable therewithin, [0032] In embodiments, a distal end of the body is between about 35 to 50 millimetres and preferably about 40 millimetres from a base of the connection means abuting with the end of the speargun barrel.

[0033] In embodiments, the body includes an anchor on the bottom of the body for a cable to be coupled thereto.

[0034] In embodiments, the anchor includes one or more transverse apertures for receiving a cable therethrough and a post for receiving a cable loop.

[0035] In another aspect, the invention provides a speargun including a barrel and a head located at a distal end of the barrel, the head including first and second pairs of refers mounted to laterally opposite sides of the body for redirecting one or more flexible elongated members in an inverter-type speargun configuration, the first pair of rollers having an axis of rotation and the second pair of rollers having an axis of rotation, wherein the axes of rotation of the first and second pair of rollers are vertically spaced apart and longitudinally offset from one another.

[0036] In embodiments, the speargun includes a handle and firing assembly coupled to a proximal end of a barrel and the head located at a distal end of the barrel. Preferably, the speargun head includes: a body; a connection means at one end of the body for fitting to the end of the barrel; first and second pairs of rollers mounted to laterally opposite sides of the body. Preferably, the axes of rotation of the first and second pairs of rollers extend transversely and laterally through the body, In embodiments, the rollers mounted to each side of the head comprise a tandem, wherein the rollers of each tandem include respective circumferential channels that are longitudinally aligned with one another for supporting and redirecting a flexible elongated member.

[0037] In embodiments, the rollers include a circumferential channel configured for receiving a cable, wherein one or more elongated rubber members are attached at one end thereof towards a proximal end of the barrel and the other ends of ths rubbers are coupted to a cable that extends to a sling at the distal end of the barrel, wherein the rubber members are adapted to be stretched by drawing the sling and the cable around the rollers and back towards the handle assembly and coupling the sling to the firing assembly and a spear.

[0038] Embodiments of the invention that minimise power losses can enable other benefits such as a shorter length for the barrel, fewer or smaller diameter or less powerful rubber members, whilst maintaining accuracy, range and manoeuvrability of the speargun. Other benefits that may be achieved by the reductions in power toss achieved by embodiments of the invention include reductions in recoil and greater ease of reloading.

[0039] In embodiments, the barrel and the head are formed integrally as a unitary piece. In embodiments, the barrel and the head and the handle are formed integrally as a unitary piece.

BRIEF DESCRIPTION OF THE FIGURES

[0040] The invention will now be described in more detail with reference to embodiments of the invention illustrated in the accompanying drawings, wherein:

[0041] Figure 1 illustrates a perspective view of a head for a speargun in accordance with an embodiment of the invention, the head including a body and first and second pairs of rollers mounted to laterally opposite sides of the body whereby rollers mounted to each side of the head operate in tandem to redirect a cable;

[0042] Figure 2 illustrates an exploded perspective view of the head of Figure 1 , showing first and second mounting locations for the rollers and fasteners and washers used to mount the rollers into position;

[0043] Figures 3 to 8 illustrate top, left side, bottom, right side, front and rear views of the head of Figure 1 ; [0044] Figure 9 illustrates a side view of a speargun configuration in accordance with an embodiment including a handle and firing assembly coupled to a proximal end of a barrel and the head of the embodiment of Figure 1 mounted to a distal end of the barrel and elongated rubber members attached at one end towards a proximal end of the barrel and the other end of the rubbers are coupled to a cable that extends to a sling at the distal end of the barrel; and

[0045] Figure 10 illustrates a side view of a speargun configuration in accordance with another embodiment including a handle and firing assembly coupled to a proximal end of a barrel and the head of the embodiment of Figure 1 mounted to a distal end of the barrel and elongated rubber members attached at one end towards a proximal end of the barrel and the other end of the rubbers including one or more pulleys redirecting a cable that is anchored at one end to the head at is coupled at another end to a sling at the distal end of the barrel

DETAILED DESCRIPTION

[0046] Figures 1 to 10 illustrate embodiments of the invention including a compact roller head 10 for a speargun 100 for launching a spear underwater to impale a fish or other marine animals. Referring to Figures 9 and 10, assembled spearguns 100, 200 in accordance with embodiments of the invention include a barrel 110, a stock 120 including a handle 130 and firing assembly 140, including a trigger 142, fixed to a proximal end 114 of the barrel 110 and a head 10 fixed to a distal end 112 of the barrel 110. The barrel 110 can be formed out of a hollow, elongated aluminium alloy or composite tube. The stock 120, including the handle 130 and firing assembly 140 can be fixed to the end 114 of the tube 110 by adhesive or a mechanical fastener or both.

[0047] The head 10 comprises a body 20 including a connection means 30 at a proximal end 22 of the body 20 for fitting to the distal end 112 of the barrel 110. The connection means 30 includes a cylindrical section 32 that is sized to be received in a relatively close fit within the hollow distal end 112 of the barrel 110. The connection means 30 may be fixed to the distal end 112 of the barrel 110 by an adhesive or a mechanical fastener or both. It is envisaged that embodiments include the body 20 and the barrel 110 formed as a single unitary piece, such as by injection moulding out of a thermoplastic. However, for convenience the embodiments illustrated and described herein comprise a separate body 20 and barrel 110 that are fixed together.

[0048] Referring to Figure 1, the body 20 of the head 10 is elongated along a longitudinal axis from the proximal end 22 to a distal end 24. The body 20 is preferably moulded, such as by injection moulding out of a thermoplastic, and is substantially solid. The body 20 has transversely opposite lateral sides 21 , 23, a top 25 and a bottom 27 extending longitudinally from the cylindrical section 32 at the proximal end 22 to a front 29 of the body 20 at the distal end 24.

[0049] The body 20 includes a first mounting location 60 and a second mounting location 70 for respectively mounting first and second pairs of rollers 62, 64, 72, 74 to the body 20.

[0050] The first mounting location 60 is for mounting a pair of rollers 62, 64 to transversely opposite sides 21. 23 of the body 20. The first mounting location 60 includes a pair of laterally outwardly extending bosses 63, 65 each containing a centrally located aperture 61 extending transversely within the body 20 for receiving a fastener 68 therewithin. The apertures 61 and the rollers 62, 64 are axially aligned about an axis X-X. Ths rollers 62, 64 rotate on the bosses 63, 65 and may also incorporate a roller bearing.

[0051] The second mounting location 70 is also for mounting a pair of rollers 72, 74 to transversely opposite sides of the body 20, The second mounting location 70 also includes a pair of laterally outwardly extending bosses 73, 75 each containing a centrally located aperture 71 extending transversely within the body 20 for receiving a fastener 68 therewithin. The apertures 71 and the rollers 72, 74 are axially aligned about an axis Y-Y. The rollers 72, 74 rotate on the bosses 73, 75 and may also incorporate a roller bearing. [0052] As will be apparent from this disclosure, the rollers 62, 64, 72, 74 are arranged in tandem an transversely opposite sides 21 , 23 of the body 20 for supporting and redirecting cables in inverter-type speargun configurations.

[0053] The location of the aperture 81 of the first mounting location 60 is vertically above and longitudinally forward of the aperture 71 of the second mounting location 70. As such, the axis of rotation X-X of the rollers 62, 64 of the first mounting location 70 is also vertically above and longitudinally forward of the axis of rotation Y-Y of the rollers 72. 74 of the second mounting location 70.

[0054] In embodiments, the axes of rotation X-X and Y-Y of the first and second pairs of rollers 62, 64, 72, 74 are angularly offset from one another in a plane extending longitudinally and vertically by an angle 8 between 0 degrees and 90 degrees, and preferably between about 5 degrees and 15 degrees. In other words, the location of the aperture 61 of the first mounting location 60 relative to the location of the aperture 71 of the second mounting location 70, is angularly displaced about the axis of rotation Y-Y of the second mounting location 70 by between about 0 and 90 degrees of between about 5 degrees and 15 degrees.

[0055] Referring to Figure 9 which shows an embodiment of the speargun 100, known as an inverter-type speargun configuration. A post 122 extending from the bottom of the handle 130 provides a base for connection of proximal ends 162 of a pair of rubber members 160. The other ends 164 of the rubber members 160 are coupled to a respective cable 101 , 103 that extends to a sling 170 at the distal end 112 of the barrel 110.

[0056] The rollers 62, 64, 72, 74 mounted to the head 10 each include a circumferential and arcuate channel 66, 67, 76, 77 configured to each receive the cables 101 , 103. The circumferential channels 66, 67, 76, 77 are radiused to assist in retaining the cables 101 , 103 therewithin and to minimise friction. [0057] On each side 21 , 23 of the head 10 the roller 62, 64 mounted to the first mounting location 60 and the roller 72, 74 mounted to the second mounting location 70 comprise a tandem A, B. In other words, on one side 21 of the head 10, the roller 62 mounted to the first mounting location 60 and the roller 72 mounted to the second mounting location 7G comprise a first tandem A and on the other side 21 of the head 10, the roller 64 mounted to the first mounting location 60 and the roller 74 mounted to the second mounting location 70 comprise a second tandem B. The circumferential channels 66, 67, 76, 77 of the rollers 62, 64, 72, 74 of each tandem A, B are longitudinally aligned with one another for supporting and redirecting the cables 101, 103.

[0058] The configuration and relative positioning of the rollers 62, 64, 72, 74 in the aforementioned tandems A, B means that the circumferential channels 66, 67, 76, 77 of the rollers 62. 64, 72, 74 of each tandem A, B respectively contact the cables 101, 103 through an angular displacement of less than 180 degrees. In the embodiments illustrated in the Figures, the circumferential channel 66, 67 of a first one of the rollers 62, 64 of each tandem A, B, namely the rollers 62, 64 at the first mounting location 60, contacts a respective cable 101, 103 through an angular displacement of more than 90 degrees and the circumferential channel 76, 77 of the second one of the rollers 72, 74, located at the second mounting location 70, contacts the respective cable 101, 103 through an angular displacement of less than 90 degrees.

[0059] Embodiments of the invention are advantageous, particularly in invertertype roller gun configurations such as in Figures 9 and 10, in that the speargun head 10 includes rollers 62, 64. 72, 74 that operate in tandem to redirect the cables 101 , 103 extending from the elongated rubber members 160 to a sling 170 at the distal end 112 of the barrel 110. As such, embodiments of the speargun head 10 enable the diameters of the rollers 62, 64, 72, 74 to be relatively small whilst still remaining operable to redirect the cables 101 , 103 and to bridge the distance between the level of the botom 27 of the head 10, at which the cables 101, 103 extend from the rubbers 160, and the level of the top 25 of the head 10, at which the cables 101 , 103 extend to the firing assembly 140 and the spear 5. [0060] In embodiments, the rollers 62, 64, 72, 74 each have a diameter of between about 5 and 15 millimetres and preferably between about 7 and 10 millimetres or any increment, in millimetres, therebetween. In embodiments, the diameter of the circumferential channels 66, 67, 76, 77 of the rollers 62, 64, 72, 74 may be between about 5 and 15 millimetres and preferably between about 7 and 10 millimetres or any increment, in millimetres, therebetween.

[0061] In embodiments, the axis of rotation X-X and Y-Y of the first and second pairs of rollers 62, 64, 72, 74 is between about 10 to 15 millimetres and preferably about 13 millimetres from a base of the connection means abutting with the end of the speargun barrel. However, the axis of rotation X~X of the first pair of the rollers 62, 64 will be further away from a base of the connection means 30 abuting with the distal end 112 of the barrel 110. to an embodiment, the axis of rotation X-X of the first pair of rollers 62, 64 is about 13 millimetres or 13.2 millimetres and the axis of rotation of the second pair of rollers is about 11 millimetres or 11.5 millimetres from the base of the connection means 30 abuting with the end 112 of the barrel 110.

[0062] The top 25 of the body 20 includes a longitudinal channel 26 for guiding the spear 5 during launch. A pair of wing members 11 , 12 extend transversely outwards from the body 20 at or near the distal end 24 thereof. The wing members 11 , 12 each include a U-shaped and forwardly open notch 13, 14. The wing members 11, 12 are adapted to support a tether cable 3 that is connected at one end to the speargun 100 and at the other end is coupled to the spear 5 to facilitate retrieval. The tether cable 3 is locatable across the channel 26 and within the notches 13, 14 on opposite sides thereof.

[0063] Ths bottom 27 of the body 20 includes a downwardly extending anchor 14 at or near the proximal end 22 thereof. The anchor 14 includes an upwardly facing and downwardly sloping surface 15 that defines a recess 16 including an open end 17 forward thereof defining a post 18 for receiving a loop of a cable in some configurations of the speargun 100. The anchor 14 also includes one or more transverse openings 19 for receiving a cable therethrough in some other configurations of the speargun 100, 200. [0064] to embodiments, the distal end 24 at the front 29 of the body 20 is between about 35 to 50 millimetres and preferably about 40 millimetres from the base of the connection means 30 abutting with the end 112 of the barrel 110. Accordingly, when attached to the end 112 of the barrel 110, the connection means 30 is located inside the hollow end of the barrel 110 and the head 10 extends from the end 112 of the barrel by up to about 35 to 50 millimetres and preferably about 40 millimetres.

[0065] The sides 21 , 23 of the body 20 include a respective recess 80, 90 configured to receive, and to at least in part shroud the rollers 62, 64, 72, 74. Each recess 80, 90 receives the rollers mounted to a side 21 , 23 of the head 20 comprising each tandem A, B. The recesses 80, 90 each include a wall 82, 92 extending in a vertical and a forwardly sloping direction. The wail 82, 92 is located opposite and spaced apart from each tandem A. B of the rollers 62, 72, 64, 74 within the respective recess 80, 90. A space 84, 94 between the wall 82, 92 and the tandem A, B of the rollers 62, 72, 64, 74 defines a passage 89, 99 for receiving and guiding the cable 101, 103 therewithin.

[0066] The passage 79 is configured to permit insertion of the cable 101 , 103 therewithin from the botom 27 or the top 25 of the body 20 and to prevent movement of the cable directly out of the passage 89, 99 to the opposite lateral sides 21 , 23. The cables 101, 103 are thereby received within the circumferential and arcuate channels 66, 76, 67, 77 of the rollers 62, 72, 64, 74.

[0067] Referring to the embodiment of the head 10 and the embodiment of the speargun 100 of Figures 1 to 10, illustrating inverter-type roller speargun configurations, the passages 89, 99 between the walls 82, 92 and the rollers 62, 72, 64, 74 are sized to receive respective cables 101, 103. The cables 101 , 103 typically employed in such applications may have a diameter of about 2 millimetres to about 4 millimetres. Accordingly, the space 84, 94 defined between the walls 82, 92 and the rollers 62, 72, 64, 74 may be between about 2 millimetres and about 5 millimetres or preferably about 3 to 4 millimetres. [0068] As mentioned above, Figure 9 shows a side view of an inverter-type speargun 100 in accordance with an embodiment of the invention. The speargun 100 indudes the head 10 of Figures 1 to 8 mounted to the distal end 112 of the barrel 110.

[0069] The rubber members 160 are adapted to be stretched by drawing the sling 170 back towards the firing assembly 140. In so doing, each of the cables 101, 103 is drawn around a respective tandem A, B of the rollers 62, 64, 72, 74 until the sling 170 reaches and is coupled to the firing assembly 140 and a spear 5.

[0070] Pulling the trigger 142 of the firing assembly 140 releases the sling 170 which thereby releases the potential energy stored in the stretched rubber members 180. The rubber members 160 cantract to their original length and in so doing draw the cables 101, 103 back the other way around the rollers 62, 64, 72, 74 and accelerate the spear 5 along the barrel 110, through the channel 26 of the head 10 and towards a target underwater

[0071] Figure 10 illustrates a side view of a speargun 200 in accordance with another embodiment. The speargun 200 is another inverter-type roller speargun configuration employing the use of one or more pulleys 210 connected to the distal ends 164 of one or more of the rubber members 160. In the speargun of Figure 10, the proximal ends 162 of the rubber members 160 are coupled to the post 122 extending from the botom of the handle 130.

[0072] The cables 101 , 103 are fixed to the anchor 14 at the head 10 and extend to the pulleys 210 atached to the rubber members 160. The cables 101, 103 are redirected by the pulleys 210 back towards the head 10. The cables 101, 103 are redirected again by respective tandems A, B of the rollers 62, 64, 72, 74 whereby the sling 170 can be drawn back to the reach and be coupled to the firing assembly 140 and the spear 5.

[0073] The spearguns 100, 200 are advantageous in that the speargun head includes rollers 62, 64, 72, 74 that operate in tandem to redirect cables 101 , 103 extending from the elongated rubber members 160 below the barrel 110 to the sling 170 above the barrel 110. Furthermore, embodiments of the speargun head 10 enable the use of relatively small diameter rollers 62, 64, 72, 74 to redirect the cables 101, 103 and to bridge the distance between the level of the botom 27 of the head 10, at which the cables 101, 103 extend from the rubbers 160, and the level of the top 25 of the head, at which the cables 101 , 103 extend to the firing assembly 140 and the spear 5. Accordingly, embodiments of the invention can be advantageous in that they include smaller rollers 62, 64, 72, 74 to thereby enable a reduction of the rotational inertia of each of the rollers 62, 64, 72, 74. Thus, the surface area of contact of each one of the rollers 62, 64, 72, 74 with the cable 101 , 103 is minimised to thereby minimise friction therebetween.

[0074] Embodiments of the invention can reduce power losses resulting from friction between rotating rollers 62. 64, 72, 74 and cables 101 , 103. Also, reductions in power losses can be achieved due to a reduction in the rotational inertia of the rollers 62, 64, 72, 74. Embodiments of the invention that minimise power losses can enable other benefits such as a shorter length for the barrel 110, fewer or smaller diameter or less powerful rubber members 160, whilst maintaining accuracy, range and manoeuvrability of the speargun 100, 200. Other benefits that may be achieved by the reductions in power loss achieved by embodiments of the invention include reductions in recoil and greater ease of reloading.

[0075] While various embodiments of the invention have been set forth above, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

Claims

Claims:

1 . A speargun head including: a body adapted for location at an end of a barrel of a speargun; first and second pairs of rollers mounted to laterally opposite sides of the body for redirecting one or more flexible elongated members in an invertertype speargun configuration; the first pair of rollers having an axis of rotation and the second pair of rollers having an axis of rotation, wherein the axes of rotation of the first and second pair of rollers are vertically spaced apart and longitudinally offset from one another.

2. The speargun head of claim 1 , wherein the rollers mounted to each side of the head respectively comprise a tandem, wherein the rollers of each tandem include respective circumferential channels that are longitudinally aligned with one another for supporting and redirecting a flexible elongated member.

3. The speargun head of claim 2, wherein the circumferential channels of each of the rollers of each tandem respectively contact the flexible elongated member through an angular displacement of less than 180 degrees.

4. The speargun head of claim 2, wherein the circumferential channel of a first one of the rollers of each tandem contacts the flexible elongated member through an angular displacement of more than 90 degrees and the circumferential channel of the second one of the rollers contacts the flexible elongated member through an angular displacement of less than 90 degrees.

5. The speargun head of claim 4, wherein the axis of rotation of the first one of the rollers is vertically above and longitudinally forward of the axis of rotation of the second one of the rollers.

6. The speargun head of claim 1 , wherein the axes of rotation of the first and second pair of rollers are angularly offset from one another in a plane extending longitudinally and vertically by between 0 degrees and 90 degrees, and preferably between about 5 degrees and 15 degrees.

7. The speargun head of claim 1 , wherein the rollers have a diameter of between 5 and 15 millimetres and preferably between 7 and 10 millimetres.

8. The speargun head of claim 1 , wherein the circumferential channel of a first one of the rollers of each tandem contacts the flexible elongated member at about the level of the top of the body and the circumferential channel of the second one of the rollers contacts the flexible elongated member at about the level of the bottom of the body.

9. The speargun head of claim 1 , wherein the circumferential channels of the rollers are radiused.

10. The speargun head of claim 1 , wherein the body includes recesses in laterally opposite sides of the body, each recess configured to receive the rollers mounted to a respective side of the head.

11. The speargun head of claim 10, wherein the recess includes a wall extending in a vertical and forwardly sloping direction, thereby defining a passage between the wall and the rollers in the recess for receiving and guiding a cable therewithin.

12. The speargun head of claim 1 1 , wherein the passage is configured to permit insertion of a cable therewithin from the bottom or the top of the body and to prevent movement of the cable laterally out of the passage.

13. The speargun head of claim 1 , wherein the axis of rotation of the first and second pair of rollers is between about 10 to 15 millimetres from a base of a connection means abutting with an end of the speargun barrel.

14. The speargun head of claim 13, wherein the axis of rotation of the first pair of rollers is about 13 millimetres and the axis of rotation of the second pair of rollers is about 11.5 millimetres from the base of the connection means abutting with the end of the speargun barrel.

15. The speargun head of claim 1 , wherein the body includes a longitudinal channel extending along the top of the body for guiding a spear during launch.

16. The speargun head of claim 1 , wherein the body includes a pair of wing members extending laterally outwards from the body at a distal end thereof, wherein each wing member includes a U-shaped and forwardly open notch for receiving a tether cable therewithin.

17. The speargun head of claim 1 , wherein a distal end of the body is between about 35 to 50 millimetres and preferably about 40 millimetres from the base of a connection means abutting with an end of the speargun barrel.

18. The speargun head of claim 1 , wherein the body includes an anchor on the bottom of the body for a cable to be coupled thereto.

19. The speargun head of claim 18, wherein the anchor includes one or more transverse apertures for receiving a cable therethrough and a post for receiving a cable loop. 30. A speargun including: a barrel and a head located at a distal end of the barrel; the head including first and second pairs of rollers mounted to laterally opposite sides of the body for redirecting one or more flexible elongated members in an inverter-type speargun configuration, the first pair of rollers having an axis of rotation and the second pair of rollers having an axis of rotation, wherein the axes of rotation of the first and second pair of rollers are vertically spaced apart and longitudinally offset from one another. 21. The speargun of claim 20, wherein the rollers include a circumferential channel configured for receiving a cable, wherein one or more elongated rubber members are attached at one end thereof towards a proximal end of the barrel and the other ends of the rubbers are coupled to a cable that extends to a sling at the distal end of the barrel, wherein the rubber members are adapted to be stretched by drawing the sling and the cable around the rollers and back towards the handle assembly and coupling the sling to the firing assembly and a spear. 22. The speargun of claim 20, wherein the barrel and the head are formed integrally as a unitary piece.