NO343632B1

NO343632B1 - Power-assisting draw weight amplifier system and crossbows comprised thereof

Info

Publication number: NO343632B1
Application number: NO20171730A
Authority: NO
Inventors: Anders Thalberg
Original assignee: Bakke Invest As
Priority date: 2017-07-18
Filing date: 2017-10-30
Publication date: 2019-04-15
Also published as: NO20171730A1

Description

TITLE

POWER-ASSISTING DRAW WEIGHT AMPLIFIER SYSTEM

AND CROSSBOWS COMPRISED THEREOF

BACKGROUND

[0001] Loading a crossbow, such as a compound crossbow, can require a high draw weight to pull back the string to the latch. A crossbow construction is specifically rigid, and requires a high tension in the string and limbs to be able to shoot a bolt (sometimes called an arrow) at required speed. Once a string is drawn it is held by a latch which holds the string until it’s released by pulling the trigger. There is a problem for archers not having the strength to exercise the required power for pulling the string far enough to reach the latch.

[0002] Unloading a crossbow can also present difficulties. When a crossbow is drawn, it is problematic to abort a shooting of the bolt. The string is drawn to maximum tension, and only release of the latch may release the tension in the string. It is not feasible to easily remove bolt and release the string. Furthermore, shooting without having a bolt in place (sometimes called a dry-fire) will potentially cause damage to the crossbow, and potentially destroy it completely. In an attempt to address this problem, abort bolts have been designed for shooting from the crossbow. The known abort bolt is designed to fly only a short way, and is made of a cheaper material than, for example, hunting bolts. Often an abort bolt is destroyed when being released into the ground. The abort bolts therefore constitutes both a cost element and a risk element. Unloading a hunting bolt from the crossbow, and then mounting the abort bolt represents risky operations on a high tension loaded crossbow. Shooting an abort bolt into the ground poses an injury risk to the shooter and bystanders.

[0003] The history has provided a number of attempts to solve these problems and disadvantages by providing devices intended to improve the ability of a shooter to draw the string of a crossbow. One known device is a mechanical cocking device having one or more hooks attached to a belt, enabling the shooter to draw the crossbow by straightening his/hers legs. Other known devices include: (a) hinged levers, which either pull or push the string into place; (b) hand-cranked, rack-and-pinion devices; and (c) multiple cord-and-pulley cranked devices, such as windlasses. All of these known devices suffer from problems and deficiencies in one or more aspects, such as: causing the crossbow assembly to be too heavy, or being too difficult, awkward, cumbersome, complex, noisy or time consuming to use.

[0004] At present, in most countries where crossbow hunting is an allowed hunting art, there are defined requirements to the power of a crossbow allowed to be used for hunting. Thus, in practice, there is a minimum draw weight required for a person wanting to participate in crossbow hunting. In order for the person to be able to operate an allowable crossbow he/she must often rely on undesired devices discussed above. In practice, this requirement to load weight disqualifies many people from taking active part in crossbow hunting. Furthermore, if hunting on big game requires specifically high draw weight to enable using larger bolts in the compound crossbow, the loading is correspondingly slower, the necessary draw force is greater, and shooting more than one bolt at an identified game species becomes problematic.

[0005] The above problems are particularly undesired in a hunting environment. The mentioned devices fail to fulfill the above-described requirements in a way that enhances the ease of use, performance and safety in the use of crossbows, including compound crossbows.

[0006] The foregoing background describes some, but not necessarily all, of the problems, disadvantages and shortcomings related to conventional crossbows.

SUMMARY

[0007] The present disclosure relates to a power-assisting draw weight amplifier system for crossbows, crossbows and other archery equipment that comprise such system, and a method for structuring, retrofitting, adapting or accessorizing crossbows with such system.

[0008] Present disclosure provides solutions to the above-stated, technical problems, and is particularly advantageous when applied to a compound crossbow, but could also be configured for use in conjunction with other types of crossbows, bows and other archery equipment.

[0009] In an embodiment, the power-assisting draw weight amplifier system includes power-assisting draw weight amplifier device(s) for enabling a crossbow user to be less dependent on time-demanding mechanical aids for drawing the crossbow to fulfill the load weight required for, for example, hunting, thus enabling persons a wider variety of allowed operations using the crossbow.

[0010] In an embodiment, the power-assisting draw weight amplifier system functions as an aid or tool, providing additional pullback power for crossbow users. The users, because of lack of muscle power, are unable to easily or steadily exert the required pulling force, and need additional power for adding extra speed or bolt weight capacity. The additional pullback power of the system can be especially helpful for long distance shooting or big game hunting where the normal minimum crossbow capacities are not adequate. In such use cases, there is a need for being able to add extra power to the crossbow shooting capabilities.

[0011] In an embodiment, the power-assisting draw weight amplifier system includes power-assisting draw weight amplifier devices for increasing the crossbow force relative to the required drawn string force. The amplifier devices further comprise relatively low weight, high power, low vibration, easy operation and low noise footprint. Further features, as described in the present disclosure, comprise a crossbow assembly which is relatively easy to manage and maintain for repeated action.

[0012] In one embodiment, the power-assisting draw weight amplifier system includes electric motor(s), and optionally gear(s), such as worm gear(s) mounted inside the crossbow construction for exerting a pulling force on limb elements and thus increasing the tension in the crossbow limbs when the string has been drawn.

[0013] In another embodiment, the power-assisting draw weight amplifier system includes pneumatic-driven cylinders mounted inside the riser constructions to provide power to the power-assisting draw weight amplifier device(s). The amplifier device(s) are arranged to exert a pulling force on limb elements and thus increase the tension in the crossbow limbs when the string has been drawn.

[0014] In yet another embodiment, the power-assisting draw weight amplifier system includes linear actuators which are mounted inside the riser construction to provide power to the power-assisting draw weight amplifier device(s). The amplifier device(s) are arranged for exerting a pulling force on limb elements and thus increase the tension in the crossbow limbs when the string has been drawn.

[0015] The disclosure, in an embodiment, the power-assisting draw weight amplifier system includes a switch device connected to the power-assisting draw weight amplifier devices that exert a pulling force on the limbs. The switch device may be able to activate and deactivate the power-assisting draw weight amplifier devices that exert a pulling force and increase the tension the crossbow limbs when the string has been drawn. When using the switch for deactivating, the safety risk of changing to and shooting an abort bolt from the crossbow is reduced, minimized or eliminated.

[0016] In an embodiment, the power-assisting draw weight amplifier system includes an electrical or pneumatic accumulator/source to provide power to the power-assisting draw weight amplifier devices that exert a pulling force on limb elements and thus increase the tension in the limbs.

[0017] Additional features and advantages of the present disclosure are described in, and will be apparent from, the following Brief Description of the Drawings and Detailed Description.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Fig. 1 illustrates an example of a prior art compound crossbow construction.

[0020] Fig. 2 illustrates an embodiment of a compound crossbow construction including single power-assisting draw weight amplifier system.

[0021] Fig. 3 illustrates an embodiment of an example of combined connection point in limb pockets to single cardan axle.

[0022] Fig. 4 illustrates an embodiment of a compound crossbow construction including dual power-assisting draw weight amplifier system.

[0023] Fig. 5 illustrates an embodiment of a worm gear.

[0024] Fig. 6 illustrates an embodiment of a linear actuator.

[0025] Fig. 7 illustrates an embodiment of a limb pocket.

[0026] Fig. 8 illustrates an embodiment of a limb pocket and motor/gear in riser, untensioned.

[0027] Fig. 9 illustrates an embodiment of a limb pocket and motor/gear in riser, tensioned.

[0028] Fig. 10 illustrates an embodiment of limb pockets/covers extended separate.

[0029] Fig. 11 illustrates an embodiment of limb pockets/covers extended connected.

[0030] Fig. 12 illustrates an embodiment of a limb pocket cover.

[0031] Fig. 13 illustrates an embodiment of a limb pocket cover employed.

[0032] Fig. 14 illustrates an embodiment of a gear wheel pulling dual wires.

[0033] Fig. 15 illustrates an embodiment of an electrical configuration.

[0034] Fig. 16 illustrates an embodiment of a pneumatic piston.

[0035] Fig. 17 illustrates an embodiment of a valve.

[0036] Fig. 18 illustrates an embodiment of a reverse draw technology crossbow including the single power-assisting draw weight amplifier system.

[0037] Fig. 19 illustrates an embodiment of a single actuator acting on a pair of pulling means connected to corresponding limb pockets viewed from an oblique backside angle.

[0038] Fig. 20 illustrates the embodiment of fig.19 from an oblique forward angle [0039] Fig. 21 illustrates the embodiment of fig.19 from an above angle

[0040] Fig. 22 illustrates a side view of the embodiment of fig.19

[0041] Fig. 23A illustrates a first alternative embodiment of the actuator assembly [0042] Fig. 23B illustrates a second alternative embodiment of the actuator assembly [0043] Fig. 23C is a side relief an alternative of the limb connecting means

[0044]

DETAILED DESCRIPTION

[0045] The present disclosure will now be described in more detail with reference to the non-limiting drawings.

[0046] Although certain embodiments are described herein with respect to a compound crossbow, it should be understood other embodiments include other types of crossbows, archery bows and archery equipment.

[0047] It shall be understood that the embodiments only describe the principle of the disclosure, and that there may be additional ways to implement the subject matter of the present disclosure. It is the associated claims that shall define the protection scope of the subject matter of the present disclosure.

[0048] Different embodiments are discussed below, and particularly two different implementation strategies or embodiments. A first implementation or embodiment of the system includes a single motor and an arrangement to transfer the output power of the single motor to both limbs in order to achieve the desired effect of increasing the tension in the limbs. A second implementation or embodiment includes a plurality of motors – one motor for each limb, having separate transfer arrangement to corresponding limb, and the motors are working independently (or in synchronized fashion) to achieve the desired effect of increasing the tension in each corresponding limb. The features and detailed implementations discussed below shall be read and understood in a manner that the constructions can be formatted to fit either of the implementation strategies, or features from the two embodiments may be mixed to achieve a comparable effect.

[0049] In an embodiment, a crossbow 1, as shown in Fig. 1, comprises a barrel 2 comprising a flight groove 3 which defines the bolt flight path and rest, a foregrip 4, stock 5 and trigger 6. The groove 3, in an embodiment, is configured to at least partially hold or support an arrow, projectile or bolt (not shown) intended to be launched in the air toward a target. In the embodiment shown, the crossbow 1 is a compound crossbow. Two risers 8 may be arranged at the front of the barrel, and constitute support for the limbs 9 protruding out to each side of the barrelectric. The attachment member attaching each limb 9 to corresponding riser may comprise a pivot member or pivot point 21 and a limb coupler 22 (e.g., a bolt, screw or other suitable fastener). A bowstring, drawstring or string 10 is attached between the outer ends of the limbs 9, and is used for shooting the bolt. A latch 7 is arranged on the back end of the barrel 2 to hold the string 10 when drawn.

[0050] A drawn string 10 provides a high tension in the limbs 9, and when a bolt is placed in the flight groove 3 in front of the tensioned string 10, and a trigger 6 is pulled with the effect that the latch 7 releases the string 10, the tension in the limbs 9 and the string 10 is released and pushes the bolt along the flight groove 3 and out of the crossbow 1 between the risers 8 and the limbs 9. Crossbow 1 can comprise a cocking stirrup 11 arranged in the front of the risers 8 being located below the flight path 3 of the bolt. The cocking stirrup 11 provides a foot grip for the shooter to aid the drawing operation of the string 10 when loading the crossbow 1, when the shooter points the crossbow 1 towards the ground, and puts his/hers foot inside the cocking stirrup 11, and grips the string 10 and pulls the string back to the latch 7. Crossbow 1 can include or be operable with other devices for aiding the loading, such as hooks and belt, cranked rack-and-pinion devices and multiple cord-and-pulley cranked devices such as windlasses.

[0051] There are several design variations to the mounting practice of the limbs/limb arms to the risers in crossbow designs. A limb arm 9 may, for example, be composed of a single limb arm or two parallel limb arms. The limb arm(s) 9 may be enclosed in a limb pocket 20 at a first end, and the first end being connected to a corresponding riser 8. A second end of the limb arm(s) provides a connector or coupling for the string 10. The first end of the limb arm 9 may be connected to the riser in at least a pivot point 21 arranged at a distance from the first end of the limb(s) 9, and the limb arm 9 may be pivotable around the pivot point 21. Closer, yet, to the first end of the limb(s) a fastener 22, such as a limb coupler 22, may be provided. If a limb pocket 20 is used, both pivot point 21 and limb coupler 22 may be comprised as integrated features of the limb pocket 20 as shown in, for example, Figs. 2 and 7-9. Other designs may be facilitated for the pivot point 21 and limb coupler 22 fastening mechanisms. In an embodiment, a certain adjustability 81 of the limb coupler 22 and first end of the limb arm(s) 9 relative the corresponding riser 8 is necessary for the power-assisting draw weight amplifier or amplifier assembly to work as shown in Fig.8 (un-tensioned), and as shown in Fig.9 (tensioned).

[0052] In a first embodiment, illustrated in Fig. 2, the crossbow 1a includes some or all of the elements, structures, components and functionality of crossbow 1. In addition, crossbow 1a includes a single power-assisting draw weight amplifier system 210. The amplifier system 210 is operatively coupled to the limbs 9 which, in turn, is operatively coupled to the string 10. The amplifier system 210 is configured and operable to generate a force acting along axis 218 (Fig. 2). In response to the force, the limbs 9 move relative to the barrel 2. As described below, this movement of the limbs 9 facilitates the loading and unloading of the crossbow 1a. In an embodiment, this movement of each limb 9 includes a pivot movement relative the associated limb pocket 20. During the pivot movement, the limbs 9 are operable to slightly pivot outward (away from axis 218) or inward (toward axis 218) similar to the opening and closing wings of a bird. In another embodiment (not illustrated), this movement of limbs 9 includes an axial movement along axis 218.

[0053] In the embodiment shown in Fig. 2, the amplifier system 210 includes a single motor 23 integrated into the crossbow 1a, for example an electrical motor 23, which is arranged in or on the underside of the barrel 2 close to the risers 8. The electrical motor 23 may be any suitable motor type, for example a DC geared motor, Electrical linear actuator, AC motor, Stepper motor, or other. The amplifier system 210 also includes: (a) a drive member or gear 24 operatively coupled to the motor 23; (b) an energy resource 41 (described below) operatively coupled to the motor 23; and (c) a switch device 42 (described below) operatively coupled to the motor 23.

[0054] The output of the electrical motor 23 is optionally connected to the gear 24, which, depending upon the embodiment, can include a worm gear 24. In the illustrated embodiment, the amplifier system 210 also includes a motion translator 212. The rotational output of the motor 23 is connected to the motion translator 212 that translates the rotational force of the motor/gear 23, 24 to a pull/push force. The motion translator 212 outputs the pull/push force to connector assembly 214, including a connector 216 coupled to each one of the limb pockets 20. The fore-aft movement of the connector assembly 214 causes each limb pocket 20 to pivot relative to the associated riser 8, in turn, causes pivot movement of the limbs 9 (relative to barrel 2) in the region of the limb couplers 22.

[0055] In an embodiment, the motion translator 212 may be constituted of one or two actuator rods/cardan shaft 25 and a nut 26 for receiving the actuator rod/ cardan shaft 25 of the motor/gear 23, 24, the actuator rod/ cardan shaft 25 being provided in the outer end with threads 30 corresponding to threads inside the nut. In this embodiment, the outer end of the actuator rod/ cardan shaft 25 protrudes through opening 101, in the limb pocket 20, and connects with the nut 26 on the far side of the limb pocket opening 101 as shown in Fig. 2, 3, and 11. The turning of the motor/gear 23, 24 generates an output that will then rotate the actuator rod/ cardan shaft 25 in the nut 26 and thereby move the nut 26 along axis 218 outwards or inwards on the actuator rod/ cardan shaft 25 based on the motor/gear 23, 24 rotation direction and speed. The connector assembly 214 then moves arm assembly 215 relative to axis 218, which causes the moving of the limb arms/ limb pocket 20 correspondingly. The pulling/pushing gain ratio, in an embodiment, is defined by the one or more gears 24 between the electrical motor 23 and the connector 25, for example worm gear 24, and also cardan shaft 25 and nut 26 winding ratio 30 as shown in Fig.3, the gain ration would be inversely proportional to the winding speed reduction ratio from motor 23 to cardan shaft 25, and then the thread translation of rotational speed to longitudinal speed in the actuator rod/ cardan shaft 25 and nut 30 threads.

[0056] To move the nut 20 mm in longitudinal direction along axis 218 will, if the thread in nut is 0.5 threads /mm, require the cardan shaft to rotate 10 times. If a worm gear 24 is connected to the cardan shaft 25 between cardan shaft 25 and electric motor 23, having a ratio of 200:1, the electric motor has to rotate 2000 times in order to move the nut 20 mm. If the work is expected to be performed in 10 sec, the output speed of the electric motor must be at least 12000 rpm. The pulling force may similarly be calculated. If, for example the motor 23 has a rotational force of 0,1 Nm, the output of the worm gear is 20 Nm, and the pulling force on the nut, if this has a 20 mm radius (20x5/0,02), would be 5000N (approx.500Kg or 1000 Lb).

[0057] In a further embodiment of the invention, as exemplified in the figures 19 to 23B, it is shown how the amplifier system 210 comprise a single actuator and a motion translator 212 being connected to a limb connecting means 219. The limb connecting means 219 may further be connected to each of the limb pockets 20 respectively via a pair of limb pocket connectors 213, the limb pocket connectors 213 may be wires, rod, kevlar rope/cable/strap/tape or other durable material providing sufficient strength. The connecting point of the limb pocket connectors 213 on the limb pockets 20 may preferably be at the far side opposite the protruding limbs 9. The single actuator is comprised by one or more motors and a gear/spindle acting on pair of limb pocket connectors 213 connecting each of the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 with the output of the gear/spindle in such a manner that, when driving the motor in a first direction, both of the first ends of the limb arms/ limb pockets 20 for moving the limbs 9 in the region of the limb couplers 22 are pulled towards the riser 198 around the pivot point 21 of the limb pocket 20. This brings each limb arm end closer to the corresponding riser 198 portion and thus increases the tension in a drawn string. When the motor/spindle is reversed, the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 is moved /pulled in opposite direction, thus relieving some of the tension in the string. The forces acting on the limb pockets 20 in the reversed pulling motion will be originating from the tension of the string, and the retaining force of the connector 213 being connected to the actuator 23, 24, 25.

[0058] The gear/spindle 231/232 acting on the limb connecting means 219, may be directly connected to the limb connecting means 219 by a rod 231, or via a spiral bevel gear 232 or the like and a gear spindle 233 for winding up a kevlar tape 234 or the like being connected in a further end to the limb connecting means 219. The limb connecting means 219 is further arranged onto the under side of or around the front end of the barrel 235. A groove 242 may be provided in the limb connecting means 219 to fit around the underside of the front end of the barrel 235.

[0059] Guiding rods 236 may be arranged for guiding the gliding motion of the limb connecting means 219. Such guiding rods 236 may be arranged on the underside of the front end of the barrel 235, and may be running from the front of the foregrip 237 to the backside of the riser 198.

[0060] The limb connecting means 219 may further provide through holes 243 for arranging the guiding rods 236 through the limb connecting means 219.

[0061]

[0062] It may further be provided a support frame 241 arranged around the spiral bevel gear 232 providing support for the bottom part of the vertical part of the spiral bevel gear 232 such that the spiral bevel gear 232 is held in position even if the forces from the winded up kevlar tape 234 pulls on the gear with grate force.

[0063] The figures 19 to 23 B illustrates a cross bow having a front end mounted dual riser 198 construction. It is however not a requirement for this embodiment, and any cross bow design may utilize this embodiment of the amplifier system 210, limb pocket connectors 213 and limb connecting means 219.

[0064] In an embodiment illustrated in Figs. 10-13, a limb cover 100 may be provided and may be attached around the first end 102 of the limbs or limb pocket 20, and provide a contact point 101 for the actuator rod/ cardan shaft 25 of the motor/gear 23, 24. Fig. 12 provides one alternative design for such limb cover 100. The extended portion providing a connecting point 101 for the connecting means may be designed such that connecting points from both limb covers overlap as shown in Figs. 10 and 11, and only one actuator rod/ cardan shaft 25 may be used to drive the movement of both first ends of the limb arms.

[0065] It is also within the scope of the disclosure to custom build a limb pocket 20 having all the above described combined features and design of limb pocket and limb cover.

[0066] When in use, the limb coupler 22 may be mounted but not tightened, and left to provide guiding for the pivot movement of the limb cover/limb pocket 20, 100 as it is drawn along axis 218 towards the crossbow when motor 23 is run and cardan shaft 25 rotates into nut 26 on the outside of the two meeting protrusions 101 of the limb cover 100.

[0067] In a further embodiment, as described in Fig. 4, a dual power-assisting draw weight amplifier system 210a is incorporated into or coupled to a crossbow 1b. In this embodiment, amplifier system 210a comprises a power-assisting draw weight amplifier assembly 220. As illustrated in Figs. 8-9, the amplifier assembly 220 includes: (a) a first set of the motor 23 and gear 24, which are connected to adjustable first end of limb arms/limb pocket 20 for altering the tension in the associated limb arms 9; and (b) a second set of the motor 23 and gear 24, which are connected to adjustable first end of the other limb arms/limb pocket 20 for altering the tension in the other limb arms 9. Each such set includes an electromotor 23 and optionally a mechanical gear solution 24, such as a worm gear 24. The amplifier system 210a also includes an optional energy resource such as a battery 41, electrical wiring (not shown) for connecting the power-assisting draw weight amplifier assembly 220 to the energy resource 41, and a switch device 42 for controlling the operation direction and magnitude of which the powerassisting draw weight amplifier system 210a shall operate. The power-assisting draw weight amplifier assembly 220 can further comprise the connector assembly 214 between the motor and gear and the limb pocket/limb arms 20. In the embodiment illustrated in Figs. 4, 8 and 9, however, the connector assembly 214 is eliminated, and the limb couplers 22, alone, couple the pockets 20 to the risers 8. Other connectors might be utilized. In an embodiment illustrated in Fig. 15, a switching device 42 may comprise multiple positions indicating controlling operation effect and current direction of the electromotor 23. The mechanical gear 24 solution may be constituted of a worm gear 24 assembly.

[0068] The power-assisting draw weight amplifier assembly 220 may be arranged in the barrel 2 construction or (as illustrated in Fig.4) in both the risers 8 of crossbow 1b. The powerassisting draw weight amplifier assembly 220 may be integrated into the barrel 2 construction/frame. Although it is possible to retrofit the power-assisting draw weight amplifier assembly 220 to conventional compound crossbows and other types of conventional crossbows and archery bows, such retrofitting may require cutting, custom fitting, mount kits or a combination thereof to achieve a stable and solid solution.

[0069] In an embodiment not illustrated, each of the amplifier systems 210, 210a includes a mount kit. The mount kit is configured to enable a user or assembler to permanently or removeably mount or otherwise attach the amplifier system 210, 210a (or any component thereof, such as assembly 220) to a crossbow or other type or archery bow.

[0070] In an embodiment, each of the amplifier systems 210, 210a may be implemented by the manufacturer of the crossbow riser or fitted to half fabricate crossbows which, in the case of system 210a, are prepared specifically for being fitted with the power-assisting draw weight amplifier assembly 220 according to the disclosure. It is an option for the manufacturer to produce a dummy frame in the portion of the riser intended for the power-assisting draw weight amplifier assembly 220, in order for the crossbow to be operational and stable even if the powerassisting draw weight amplifier assembly 220 is not immediately installed. Typically, the limb arms and limb pockets are specifically designed to be used with the power-assisting draw weight amplifier assembly 220.

[0071] In an embodiment, each of the amplifier systems 210, 201a comprises an electrical powered motor 54 and gear, for example a worm gear 50 as illustrated in Fig.5, which may constitute the power-assisting draw weight amplifier assembly 220 as shown implemented in Fig. 2 or 4. The gear 50 comprises an actuator arm 51a, 51b connected to the gear wheel 59 which in Fig. 5 is illustrated in two alternative positions. The actuator arm 51a, 51b may be connected to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. The solid line actuator arm 51a illustrates the position when the actuator arm is in a non-tension amplifying position, whilst the dotted line actuator arm 51b illustrates the position when the gear wheel 59 has moved in the forward direction 53, and the actuator arm is in a tension amplifying position. The motor may be an electromotor, pneumatic motor or pneumatic digital motor, spring based motor or other. By applying a positive power to the motor 54, the force from the motor 54 is transferred to the threaded rod 56 via a gear 58, and drives the gear wheel 59, interacting with the sprocket teeth to move the actuator arm 51a, 51b from a first position to a second position. When reaching the second position, the gear rotation may be stopped by a physical stopper (not shown). The second position may be arranged to be at the return side of the center line 55 of the gear wheel 59. In this way, when the actuator arm 51b is in the tension amplifying position, the second position, the reverse tension force from the limb arm will ensure that the actuator arm 51b will remain in the tension position on the return side of the center line 55 of the gear wheel 59 until the worm gear actively drives the actuator arm 51a, 51b towards the non-tension position by reversing the action of the gear.

[0072] Figs. 2-4 show each of the amplifier systems 210, 210a implemented on a Normal Draw Technology crossbow. Each of the amplifier systems 210, 210a may, however, also be implemented on crossbows designed according to a Reverse Draw Technology. As shown in Fig. 18, such a crossbow 1c (shown in fragmentary view) has limb arms that rest on risers being arranged on the barrel in the longitudinal direction almost back at the level of the trigger, and the limb arms point forward (fork like). Since the risers in these designs typically offer a support face for the limb arms/pockets on surfaces mostly parallel with the barrels, the power-assisting draw weight amplifier assembly 220 must exert a pulling force mainly diagonally to the barrelectric. One alternative for providing this may be to use one motor 23 and one gear 24 having a gear wheel 59 comprising a wire/connecting device 141, 142 for each limb pocket as illustrated in Fig. 14 (only gear wheel shown), and when turning the gear wheel 59, the wire connecting points will be moved from a start position to an end position wherein the first position will exert least assisted draw weight, and the second position will exert the most assisted draw weight to the limb pocket. This results in the limb pocket being pivoted around the pivot point 21 and an increase in the tension in the limbs 9.

[0073] Worm gears 24, 50 further provide the feature that they are practically unmovable by alternating forces exerted by the output side, the string and limbs. This means that it is possible to provide a holding force between the two above discussed end points of the worm gear, such as half-way or 90% of max string pull force, or any other level between 0 and 100%.

[0074] In a further embodiment illustrated in Fig. 6, each of the amplifier systems 210, 210a comprises a linear actuator 60 comprising an electric motor 67 connected to a spindle 64 which is rotationally coupled to a nut 63. The nut is connected to a first end of the actuator arm 61, and the second actuator arm end 62 is connected to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, is illustrated in Fig. 6. The electric motor 67 provides the rotational force and movement to the spindle 64. When the spindle 64 rotates, the nut 63 will translate the rotational movement to linear movement of the actuator arm 61 and the actuator arm end 62. The actuator arm end 62 may be connected to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22.

[0075] The linear actuator 60 may also be arranged to have one or two stoppers 65, 66 to define a first and second end of the movement range of the piston rod 61, wherein the first stopper 65 defines a position for when the nut 63 reaches the first stopper 65 the first end of the limb arms/ limb pocket 20 is in a non-tension amplifying position. The second stopper 66 defines a position for when the nut 63 reaches the second stopper 66, and the first end of the limb arms/ limb pocket 20 is in a tension amplifying position.

[0076] Linear actuators come in a variety of different designs, and Fig. 6 is only one optional design that may be used in the amplifier system 210. It is within the scope of the disclosure to use any suitable linear actuator, substituting the one used in the example in Fig.6.

[0077] It is within the scope of the disclosure to use any suitable spindle/screw actuator, substituting the one used in the examples shown in the figures.

[0078] In the embodiments where an electrical motor and a power controller/switch 42 as seen in Fig. 15, are operable to drive the motor in one direction when switch 42 is in a first position, the switch 42 may offer a plurality of positions. When the switch 42 is in a second neutral position, there is no power connected to the motor, and when the switch is in a third position, the motor drives in a reverse direction. The switch 42 may be biased or predisposed to be at rest in the second neutral position. The switch 42 may further be of a momentary switch type requiring the switch 42 to be continuously held in the first or third position to be able to feed the motor with power from the battery 41, and thus providing high flexibility in when to start and stop the power supplied by the power-assisting draw weight amplifier system 210.

[0079] In yet a further embodiment, each of the amplifier systems 210, 210a may be composed of a single actuator. The single actuator is comprised by one or more motors and a gear/spindle acting on a pair of wires (not shown) connecting each of the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 with the output of the gear/spindle in such a manner that, when driving the motor in a first direction, both of the first ends of the limb arms/ limb pockets 20 for moving the limbs 9 in the region of the limb couplers 22 are pulled. This brings each limb arm end closer to the corresponding riser and thus increases the tension in a drawn string. When the motor/spindle is reversed, the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 is moved in opposite direction, thus relieving some of the tension in the string.

[0080] Each of the power-assisting draw weight amplifier systems 210, 210a may advantageously be applied when the string 10 can initially be pulled to a tension having approximately 50% of required tension, and let the power-assisting draw weight amplifier system 210 add the final tension. However, in yet a further embodiment, each of the powerassisting draw weight amplifier systems 210, 210a may provide a solution for adding tension in a manner requiring little, minimal or no manual work by the shooter. In one example, the shooter may grasp a slideable grip (similar to a pump load grip type of a shot gun) for pulling the string 10 back until reaching a latch, similar to the action provided by pump action shot guns. In such example, slideable grip is operatively coupled to the barrel 2 and is also operatively coupled to the string 10. Using either power-assisting draw weight amplifier system 210, 210a in such a scenario requires a longer angular movement capability of the limb pocket around the pivot point, as the first tension provided by the manual action will be less. This will typically be usable with a magazine type of loading and shooting multiple bolts in succession.

[0081] In an embodiment, each of the amplifier systems 210, 210a includes a movement sensor. The sensor is incorporated into or coupled to the worm gear, solenoid, or linear actuator. The sensor may be operable to identify their operation modus.

[0082] The sensor output may be displayed to the user via a display 75, and/or they may be stored in a storage device (not shown) which may be comprised in the display unit 75, for later transfer to a processing device for analysis. For example the output from sensors 37 may be used for maintenance and adjustment purposes. In one embodiment, a wireless communication device may be connected to the sensors 37 for communicating the sensor data to a remote device. The communication may be in real time.

[0083] In a further alternative embodiment illustrated in Fig. 16, the amplifier system 210a includes a plurality of power-assisting draw weight amplifier assemblies 120 connected to the adjustable first end of limb arms 9/limb pocket 20 for controlling the tension in at least both the limbs 9. The power-assisting draw weight amplifier assemblies 120 are connected to an energy resource/storage 41, such as a pressurized gas container, via supply lines 138, 139 such as air hoses. This connects, gas communication wise, the power-assisting draw weight amplifier assemblies 120 with the energy resource 41 via a valve/controller 180 and switch device 42. The actuator may be comprised of a pneumatic cylinder 133/piston 122 using compressed gas/air (or vacuum) at high pressure, or in further embodiments: a hydraulic actuator comprising a fluid motor using hydraulic power, or magnetic solenoids or the like using permanent magnets or electro magnets, and an energy resource such as a battery 43. In the latter case, the supply lines 138, 139 will be comprised of electrical wiring. All actuators will use an energy reservoir, being one of pressurized gas or fluid stored or created in for example a pressure container 41, or electrical energy stored in for example a battery 41.

[0084] The power-assisting draw weight amplifier 220a, shown in Fig. 16 and 17, includes a pneumatic piston 122-cylinder 133 assembly. The piston 122-cylinder 133 assembly 136 is comprised of a piston 122 arranged in a cylinder 133, wherein a pressure chamber 121 is defined by the piston head 122 surface and the cylinder side 133 and bottom wall 134. The cylinder 133 may further be enclosed by a cylinder top 132, wherein the cylinder top 132 comprises a conduit through which a piston rod 123 is arranged. The pressure chamber 121 is in pneumatic gas communication, via a gas/air hose 138, 139, through a conduit 142 in the cylinder bottom wall 134 or lower part of the cylinder wall 133, with a pressurized gas reservoir 41. A valve 180, as shown in Fig. 17, between the gas reservoir 41 and the pressure chamber 121 controls the transfer of gas between the gas reservoir 41 and the air hose 138, 139 connected to the pressure chamber 121, and between the pressure chamber 121 via the air hose 138, 139 and a pressure relief reservoir 185. The pressure relief reservoir 185 may be comprised by the surrounding “free air”. The power-assisting draw weight amplifier 220a further comprise a lever /actuator arm 125, 126, 127 wherein the lever arm 125, 126, 127 is arranged to transfer the force generated by the expanding pressure chamber 121 via a cardan shaft 128 to the limb arms / limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 in a way that when the pressure chamber 121 is expanded, the piston rod 123 connected to the moving piston 122 will pivot the lever arm with the effect that the attached first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, is drawn towards the crossbow risers 8, and the pulling force on the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 is translated to an increase in the tension in the limbs 9 and the crossbow string 10, and hence the draw weight is increased. The cardan shaft may be the limb coupler itself, thus the limb coupler may be arranged to be fastened directly to the lever arm 125, 126, 127 via a connection point 130.

[0085] The valve 180 may be manually or electrically adjustable for adjusting gas pressure output level, and may additionally comprise an adjustable output gas volume regulator for controlling the output gas flow speed and/or the amount of gas volume outputted from the valve each time the switch 42 is operated to activate a gas feed cycle.

[0086] In one embodiment of the amplifier system 210a, the lever arm 125, 126, 127 comprise a resistance arm 126, an effort arm 125 and a fulcrum 127. In a first outer end of the lever arm, the effort arm 125 is connected to a first end 124 of a piston rod 123 which in its opposite second end is connected to the piston 122. In the other second end of the lever arm, the resistance arm 126 is connected to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. The lever arm rotates around a fulcrum 127 (pivot point) such that when the pressure in the pressure chamber 121 increases, the effort arm 125 is moved away from the pressure chamber 121 by the piston 122 and piston rod 123, and the resistance arm 126 will act on and exert a pulling force on the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. The ratio between the effort arm and the resistance arm defines the force amplification from the force applied by the cylinder rod effective on the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22.

Flimbbolt = (Leffort/Lresistance) * Fcylinderrod

[0087] In a further embodiment of amplifier system 210a, the cylinder 133, piston 122 and piston rod 123 may be coupled directly to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. The pressure chamber 135 for the cylinder will then be at the opposite side of the piston 122, namely on the side of the piston rod 123. The cylinder side wall 133 will be similar as the above example, but the cylinder top 132 comprise an air tight conduit for the piston rod/ actuator arm 123 to be arranged inside, the piston rod 123 protruding outside the cylinder 133 and is directly connected to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. In this embodiment, the cylinder will be open on the side 121 of the piston not being connected to the piston rod, the opening has atmospheric pressure by an opening in- or absence of- the cylinder bottom wall 134. In this embodiment, there will be no amplification of the force applied to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 by the pressure increase in and expansion of the pressure chamber 135; hence, the gas pressure supplied to the power-assisting draw weight amplifier assembly is higher. Therefore, also a more robust design is provided. The design is further adapted to the reduced piston surface area as a result of the piston rod being mounted on the active piston surface side. The size of the cylinder and piston is adapted correspondingly to be able to execute the required force on the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. A corresponding conduit 142 and pressure gas/air hose 138, 139 (drawn in dotted line in Fig. 16) will be arranged in either the cylinder top 132 or in the cylinder wall 122 close to the cylinder top 132.

[0088] The two latter described embodiments are both pneumatic pressure chamber devices, and the energy storage 41 is comprised of a pneumatic accumulator. A pressure pipe/air hose connects the pneumatic accumulator 41 to the power-assisting draw weight amplifier assemblies via a pipe/air hose 138, 139. The connection further comprises a valve 180 for controlling the gas flow through the pressure pipe/ air hose 138, 139 such that the pressure chamber 121,135 of the power-assisting draw weight amplifier assemblies 120 is in pneumatic communication with the pneumatic accumulator 41. The valve 180 may further be functioning as a pressure reduction valve (not shown), since the pressure in the accumulator 41 normally is much higher than what is required by the power-assisting draw weight amplifier assemblies 120 to work. This is the case at least when the pneumatic accumulator is fully charged. The pneumatic accumulators 41 may be replaceable and/or rechargeable. Although the accumulator may be arranged in any place on the crossbow assembly, it is advantageously to arrange it in a location where it will influence as little as possible on weight balance and resonance of the crossbow operation.

[0089] In a further embodiment of amplifier system 210a, the valve 180, reduction valve and for example a silencer 184 may all be comprised in an attachable, pneumatic accumulator assembly. In such an embodiment, the elements of the disclosure comprised in the crossbow may be fewer, hence cheaper and faster to produce, and easier to maintain. The pneumatic accumulator assembly may be comprised of individual parts assembled before being mounted to the crossbow. A pneumatic accumulator assembly consisting of individual mountable/exchangeable parts such as pneumatic accumulator 41, reduction valve 187 and silencer/muffler 184 may be advantageous since there is a difference in lifespan of the different parts, which means they require replacement at different intervals. The valve 180 has a much longer lifetime then the silencer/muffler 184, which again has a longer lifetime than the pneumatic accumulator 41.

[0090] The switch 182 may be operated between two or more positions, where each position uniquely defines a valve 180 and/or pressure mode. Another switch type offers only one operation mode (such as a push button) which may toggle the different modes of the valve.

[0091] It is within the scope of the disclosure to use a digital switch and an electrically powered valve. The switch may offer a display to identify the current state of the switch, and identify selectable switch modes.

[0092] When a bolt is released in a shooting cycle or the shooting cycle is aborted, the cylinder 22 may be moved back to its initial position biased by the setup tension in the crossbow string and the limb arms in next loading session.

[0093] Each of the amplifier systems 210, 210a may comprise a display 75, such as for example an identification light, digital screen or electrical/non-electrical gauge/meter coupled to one or more sensors 37 to identify the tension status of the actuators, limbs and/or string. For example can a green light be configured to identify that the string tension has reached the required tension, and a red to identify that the string tension returned to a lower thresholds value. It would be advantageous to use a low intensity light in order to minimize the risk that a game could be disturbed or warned by the light. In case the display 75 requires electrical power, at least a power source is incorporated in the display 75 or is attachable to external power source. The external power source may be the power accumulator 41.

[0094] In an embodiment, each of the amplifier systems 210, 210a includes optional sensors 37 for detecting one or more of tension level, battery power level, gas pressure, movement, temperature, and other parameters throughout the applicable power-assisting draw weight amplifier system 210 or 210a.

[0095] In one embodiment, the implementation of the switch/valve 180 of amplifier system 210a may be for operation in a manual operation mode, meaning it has to be actively switched between operation modes. The intention is that, under operation of the crossbow, it is desirable to be able to activate the power-assisting draw weight amplifier 210a after the crossbow string 10 is fully drawn and when a bolt release is imminent. If bolt release is aborted or delayed, it is possible to switch the power-assisting draw weight amplifier system 210a to a relieve state which results in the extra tension to be reversed, and return the power-assisting draw weight amplifier 210a back to initial state. If the power-assisting draw weight amplifier assemblies 120 include a worm gear, solenoid or linear actuator, the piston rod/axle of the worm gear or linear actuator is movable between at least two positions defining a crossbow string tension amplifying position, and a crossbow string non-tension amplifying position.

[0096] The valve may, in the a worm gear or solenoid version, provide a stepwise movement of the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, or in the case of using pneumatic version of the tension amplifier, be implemented to offer a stepwise reduction valve feature, such that it can be operated to “give” pressurized gas at different pressure, for example two states where the gas can be supplied, for example, at either 3 or 5,0 atm. Such steps may be adjustable by an indicator on the valve, or by a selection mode on the switch. Another option is to design the switch such that the valve allows a portion of pressurized gas to flow from the accumulator 41 each time the switch is operated, such that it is possible to stepwise increase the pressure in the pressure chamber.

[0097] In one embodiment, the switch 42 may be operated in a semi-automatic or automatic manner. One example is that the switch/valve may be automatically switched to a relieve state when the crossbow string is released. This may be achieved by connecting the switch/valve control to a sensor on the crossbow riser/latch or other.

[0098] In a further embodiment, each of the amplifier systems 210, 210a includes a switch for setting the operation of the draw weight amplifier in a fully automatic operation mode. The fully automatic operation mode will automatically switch the draw weight amplifier to the load state once the crossbow string is drawn, and to the relieve state once the bolt is released. The switch may in this case be connected to sensors detecting string position. In this operation mode, the switch/valve operation may be controlled in various manners. One is to let a tension sensor identify when the crossbow string is drawn, and then activate the load state of the draw weight amplifier. Such sensors may be arranged in the latch, or on one or both limbs 9 of crossbow 1a or 1b. Other arrangements for detecting the bolt draw and release phase may be facilitated by the skilled person.

[0099] The semi-automatic and/or automatic operation modes may be fully mechanical or part/full electrical powered.

[0100] The limbs/limb pockets pivot angle controls the tension in the limb arms 9 of compound crossbows 1a, 1b, 1c. The limb arms 9 of the crossbow typically are mounted to the crossbow riser 8 in one end, the connector can include a pivot member or pivot point 21 and a limb coupler point 22. The pivot point 21 is a connection point between the limb 9 and the riser 8 at which the limb 9 can pivot as far as the adjustment of the limb coupler 22 allows. In the other end of the limb, a cam 12 or idler 13 wheel may be arranged. The adjustment range of the limb pocket relative the riser when the string is drawn may be described in the max tension required to draw the crossbow, e.g., 60 – 80 lbs. or more. The effect of the force transferred to the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22 when the gear is activated, when initial draw weight is set to require 140 lbs. for drawing, is the result of the additional force generated by the motor and transferred by the worm gear to increase the crossbow string tension to, for example, 200 lbs.

[0101] When the power-assisting draw weight amplifier system 210a comprises a worm gear or linear actuator 23 or 60, as shown in Fig. 5 and 6, the worm gear or linear actuator 23 or 60 may be driven by an electrical motor. In the case of electrical motor, wiring 138, 139 (Fig. 16) transfers electrical power from the electric power accumulator 41, such as a battery 41. A directional switch provides forward and reverse function of the worm gear or linear actuator such that, for example, when the worm gear or linear actuator assembly is used when the powerassisting draw weight amplifier assembly is in the load state pulling at the limb arms/limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, the cardan axle is retracted, and when in the relieve state, the axle is moved to its extended position.

[0102] When an electrical motor is used, as in the case of the power-assisting draw weight amplifier system 210a comprising the worm gears or linear actuators, the power source may be fed by an electrical accumulator, wherein the electrical accumulator, such as a battery 41, is connected to the crossbow 1a or 1b in the same manner as described above, or the electrical accumulator is remote and, for example, carried by the user of the crossbow 1a, 1b or 1c. A connecting cable may then in a first end be attached to the accumulator, which may be a battery 41, and in the other end be connected to a connection point provided in the crossbow assembly. The electrical current provided by the accumulator may then be led by electrical wiring from the connecting point to the worm gears or linear actuators via the directional switch device.

[0103] The contact point may be arranged in the grip area of the crossbow 1a, 1b or 1c.

[0104] The power reservoir, whether it is an electrical power source, a gas accumulator, or fluid accumulator may be provided in different sizes, typically customized for intended use and practical adjustments.

[0105] In a further embodiment, each of the amplifier systems 210, 210a involves utilizing a cam-action for controlling the movement of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, and driven by the above described actuators, for example the worm gear or the pneumatic pressure arrangement to rotate the cam. The advantage with using a cam is that it will allow a defined action complete state. The cam can be designed to have a contact orbit which contacts the upper side of the connection means to the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22, and be rotating around the fulcrum in the case the actuator is a pneumatic pressure arrangement, and in the case a worm gear, is used as an actuator so that the cam may rotate around the center of the gear wheelectric.

[0106] In a further embodiment, each of the amplifier systems 210, 210a involves using the tension amplifying assembly to increase the distance between the limb arms and the riser in a connection point of the pivot point, pushing the pivot point 21 rather than pulling the first end of the limb arms/ limb pocket 20 for moving the limbs 9 in the region of the limb couplers 22. In practice, this comprises mounting the pivot point to a movable pivot base providing a distance between the riser and the limb pocket in the region of the pivot point, and being able to move the pivot base by the piston rod/axle of the worm gear or linear actuator in a manner that, when the switch is in load position, the pivot point moves closer to the first end of the limbs 9 increasing the tension in the crossbow string, and when the switch is in the relieve state, the pivot point is moved back away from the first end of the limbs and thus relieve the tension in the crossbow string.

[0107] In an embodiment, in the event the power-assisting draw weight amplifier system 210 or 210a is included in the production phase of a crossbow itself, all parts may be integrated into the barrel or the riser or a combination thereof, and the crossbow construction itself will provide support and mounting arrangements for the different parts of the power-assisting draw weight amplifier system 210 or 210a, as applicable.

[0108] In the case the power-assisting draw weight amplifier assembly 20 is retrofitted, it can further require that the riser be modified or arranged for mounting pipes/cabling, switch, valve, sensor and the like described above.

[0109] In an embodiment, a crossbow (including, but not limited to, crossbow 1a, 1b or 1c) is manufactured, fabricated, formed or structured according to a method. The method of structuring a crossbow, in an embodiment, includes: (a) providing a crossbow body that includes a barrel; (b) structuring or configuring the body to house or receive an energy resource and a switch device; (c) structuring or configuring the barrel to house or receive a motor and a motion translator; and (d) coupling the motion translator to the limbs of the crossbow.

[0110] Additional embodiments include any one of the embodiments described above, where one or more of its components, functionalities or structures is interchanged with, replaced by or augmented by one or more of the components, functionalities or structures of a different embodiment described above. For example, an additional embodiment of a power-assisting draw weight amplifier system includes any suitable combination of any compoments or elements of power-assisting draw weight amplifier systems 210 and 210a. Likewise, an additional embodiment of a crossbow or archery bow includes any suitable combination of any compoments or elements of crossbows 1a, 1b or 1c.

[0111] It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the associated claims.

[0112] Although several embodiments of the disclosure have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the disclosure will come to mind to which the disclosure pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the disclosure is not limited to the specific embodiments disclosed herein above, and that many modifications and other embodiments are intended to be included within the scope of the associated claims. Moreover, although specific terms are employed herein, as well as in the associated claims, they are used only in a generic and descriptive sense, and not for the purposes of limiting the present disclosure, nor the associated claims.

Claims

1.

A power-assisting draw weight amplifier for archery equipment having limb arms (9) mounted in limb pockets (20), the limb pockets (20) being arranged in a pivot point (21) in a riser (8) being pivotally rotatable around the pivot point, comprising:

an actuator (23, 24, 25) for moving a motion translator when connected to a power source via a switch (42),

the motion translator (212) being connected to the limb pockets (20) via a limb connecting means (25, 58, 130, 219) , and limb pocket connectors (22, 30, 128, 141, 142, 213), such that when motion translator (212) being moved towards the actuator (23, 24, 50, 60, ) it rotates the limb pocket (20) around the pivot point (21) in a direction such that the tension in the limb arms (9) increase, and when motion translator being moved away from the actuator it rotates the limb pocket around the pivot point in the opposite direction such that the tension in the limbs decrease.

2.

The power-assisting draw weight amplifier of claim 1, wherein the archery equipment is a crossbow (1).

3.

The power-assisting draw weight amplifier of claim 1, wherein the motion translator is a rod (231) for direct connection between the actuator and the limb connecting means.

4.

The power-assisting draw weight amplifier of claim 1, wherein the motion translator is comprised of: a spiral bevel gear (232) providing a gear spindle (233),

a windable connector (234) being winded to the gear spindle in a first end and connected to the limb connecting means (219) in the other end.

5.

The power-assisting draw weight amplifier of claim 4, wherein the windable connector (234) is one of a Kevlar rope, Kevlar cable, Kevlar strap, tape, wire or other durable material having high strength.

6.

The power-assisting draw weight amplifier of claim 1, wherein the power-assisting draw weight amplifier further comprise a battery (41) connected to the actuator via electrical wiring and the switch (42), and the actuator comprise an electric motor (23).

7.

The power-assisting draw weight amplifier of claim 6, wherein the electrical motor is one of a DC geared motor, electrical linear actuator, AC motor and Stepper motor.

8.

The power-assisting draw weight amplifier of claim 6, wherein the actuator further comprise a gear.

9.

The power-assisting draw weight amplifier of claim 8, wherein the gear comprised in the actuator is one of a worm gear, solenoid or linear actuator.

10.

The power-assisting draw weight amplifier of claim 1, wherein motion translator being arranged under barrel of the archery equipment and the limb connecting means comprise a groove (242) for optimal sliding fit to the form of the underside of the barrel of the archery equipment.

11.

The power-assisting draw weight amplifier of claim 1, wherein the archery equipment comprise one or more guiding rods for providing support and guiding of the limb connecting means, where the limb connecting means further comprise through holes (243) for receiving the guiding rods such that the limb connecting means can be slided along the barrel of the archery equipment.

12.

A power-assisting draw weight amplifier for archery equipment having limb arms mounted in limb pockets, the limb pockets being arranged in a pivot point in a riser being pivotally rotatable around the pivot point, comprising:

one actuator for each limb pocket for moving a motion translator when connected to a power source through a switch,

the motion translator being connected to the limb pockets via limb pocket connectors such that when motion translator being moved towards the actuator it rotates the limb pocket around the pivot point in a direction such that the tension in the limb arm increase, and when motion translator being moved away from the actuator it rotates the limb pocket around the pivot point in the opposite direction such that the tension in the limb decrease.

13.

The power-assisting draw weight amplifier of claim 12, wherein the archery equipment is a crossbow.

14.

The power-assisting draw weight amplifier of claim 12, wherein the motion translator is a rod for direct connection between the actuator and the limb pocket connectors.

15.

The power-assisting draw weight amplifier of claim 12, wherein the motion translator is one of a kevlar rope, kevlar cable, kevlar strap, tape, wire or other durable material having high strength for direct connection between the actuator and the limb pocket connectors.

16.

The power-assisting draw weight amplifier of claim 12, wherein the power-assisting draw weight amplifier further comprise a battery connected to the actuator, and the actuator comprise an electric motor.

17.

The power-assisting draw weight amplifier of claim 12, wherein the electrical motor is one of a DC geared motor, electrical linear actuator, AC motor or Stepper motor.

18.

The power-assisting draw weight amplifier of claim 16, wherein the actuator further comprise a gear.

19.

The power-assisting draw weight amplifier of claim 18, wherein the gear comprised in the actuator is one of a worm gear, solenoid or linear actuator.