Abstract:
An archery or similar projectile launching device having a spring assembly to energize the device and a release mechanism to transmit energy stored within a torsion or alternative spring to the bowstring, so as to accelerate an arrow nocked to the bowstring once the trigger is released. In one embodiment, conjoined cranks wind a torsion spring within a spring motor affixed along the riser of the bow while the bowstring and arrow are concurrently brought into the discharge position. A mechanical advantage may be achieved with the cranking mechanism to reduce the effort exerted by the archer and thereby increase accuracy, velocity and ease of use.

Description:
[0001]    This application claims priority from U.S. Provisional Patent Application 60/952,887 for a “TORSION SPRING DEVICE FOR PROPELLING A PROJECTILE,” filed Jul. 31, 2008 by J. Ryan Howard et al., which is also hereby incorporated by reference in its entirety. 
     
    
       [0002]    The disclosed device relates in general to a force amplifying bow or similar device for propelling or launching a projectile, and more specifically, to an improved bow using a torsion spring as an energizing means that is operatively associated with the bowstring to thereby improve accuracy, arrow velocity and ease of use. 
       BACKGROUND AND SUMMARY 
       [0003]    In archery, and particularly bow hunting, arrow speed is dependent upon several factors, one being the amount of energy or force the bow is able to develop and deliver to the arrow. Generally speaking the more total energy put into the bow, the faster the arrow will be propelled. Increased arrow speed is desirable, especially when hunting with or shooting heavy arrows and over greater distances. However, the operation of a bow with greater energy or force is difficult because of the effort required to draw the bowstring, and for this reason many people are not capable of producing sufficient force to provide a traditional bow (e.g., compound bows) with the necessary energy to effectively propel the arrow. Even persons who have sufficient strength to draw a bow find it difficult to shoot accurately since aiming the bow and holding the drawn bowstring must be accomplished simultaneously, absent any extraneous motion, and the drawn position must sometimes be maintained for many seconds and even minutes before the target is clear for a shot. 
         [0004]    In response to the shortcomings of the long bow and recurve bow, the compound bow was developed. The compound bow offers several mechanical advantages over traditional straight and recurve bows. By and large, compound bows provide more thrust than non-compound bows, and often have a “let-off” whereby the bow may be maintained in a drawn position with less force than was necessary to initially draw the bow. Also, a compound bow is generally more compact in terms of size for a given energy capacity. 
         [0005]    In order for a compound bow to be effective, by current standards, it must be capable of producing a specific level of performance in terms of arrow velocity and accuracy. Acceptable performance with respect to arrow velocity is defined within industry standards established by the Archery Trade Association (ATA) where about a 60 lb. peak draw force, being drawn back a distance of 30 in. will propel a 540 grain arrow at a velocity within a range of 200 to 250 feet per second (140-170 MPH). Accuracy, on the other hand, is subjective because the level of precision shooting obtainable with any given bow is not controlled by the bow alone, but rather the product of the bow/arrow/archer combination. However, one characteristics of a bow design that tends to be more influential towards accuracy is arrow velocity. The trajectory, or arc, of an arrow is increasingly diminished (i.e., closer to a straight-line) as arrow velocity increases, therefore providing a more predictable and straight-line placement of the arrow relative to the target. 
         [0006]    Accordingly, a compound bow is designed to provide a mechanical advantage in order to reduce the force that an archer must apply to the bow while increasing the overall energy stored by the bow. Most compound bow designs use cams or elliptical wheels on the ends of the riser to optimize the leverage exerted by the archer and to reduce or “let-off” the holding force of the bow as a full draw is approached. Let-off, as noted above, is when the force required to hold the bowstring at full draw is substantially less than the force required to draw or hold the bowstring in an intermediate position between the undrawn and fully drawn positions. Upon release of a bowstring, which has been loaded with an arrow, the force propelling the arrow at a given position while nocked on the bowstring is proportional to the force required to hold the bowstring stationary in that position. In accordance with an aspect of the disclosed embodiments, using means such as levers to provide mechanical advantage, and a drawing mechanism, less force is required to hold a bow at full draw. As a result the muscles take longer to fatigue, thus giving the archer or hunter sufficient time to relax and aim, similar to the advantages of a compound bow or even a cross bow. In accordance with other aspects of the devices disclosed herein, the adjustability of such devices permit the use of the device across a wide range of users (e.g., sizes, arm length, strength), and permit a smaller size than conventional archery equipment. 
         [0007]    In recent years, a number of improvements have been made to compound bows; most notably the use of the bowstring and associated springs to store potential energy having a non-linear power curve. This has proven to significantly enhance the overall control of the force applied to the arrow when the bowstring is released because the high potential energy is not instantaneously captured by the arrow in the form of kinetic energy at the moment the bowstring is released, thereby avoiding accuracy degradation resulting from the imparted shock. 
         [0008]    In this regard, compound archery bows have been devised by generally utilizing a rigging of the bowstring with respect to one or more cams or pulleys that are rotatably mounted to a riser having a compression spring therebetween. In this configuration the bowstring is pulled by the archer to compress or expand the springs having an arrow nocked to the bowstring. While the flexible bowstring remains an effective means to transmit the propelling force from the spring to the arrow, it is less than effective as a “crank” to wind up springs due to its small cross-section and flexibility. An improvement to conventional devices includes applying a rotational force to a “spring,” as found in the disclosed embodiments. Although various means for energizing the spring may be disclosed, one means includes a rigid lever having an ergonomic handle, such that the lever may be employed to energize the spring. In the case of a bow, the disclosed embodiment serves to relieve the archer of discomfort resulting from pulling on a string with the index and middle fingers (or via a wrist-attached release mechanism) by providing a discrete rigid lever action member having a user friendly linkage to place the bow in a fully drawn position, without the archer having any direct interaction with the loaded bowstring and arrow. Such a device is not only believed to provide an adjustable (customizable) archery device, but to further improve safety by reducing the likelihood or unintentional release of arrows when a user exerts significant draw force. 
         [0009]    Accordingly, it is the object of the disclosed embodiments to provide a bow with a linked lever for the angular rotation of at least one spring motor to provide a propelling force to the bowstring, which thereby transfers the force to the arrow shaft. 
         [0010]    It is also an object of the disclosed device or system to provide a spring driven, high-energy “bow” wherein the required drawing and holding force may be achieved independently of the bowstring, the bow also having a trigger or similar mechanism for the release and transfer of the spring-stored energy to the bowstring. 
         [0011]    In accordance with yet another aspect of the disclosed device, the spring driven bow includes a bowstring that is directly linked or connected to elements of at least one spring motor. 
         [0012]    Another object of the inventive device is to provide an archery bow in which at least one wound torsion spring is used as the energy storing medium. 
         [0013]    It is a further object to provide an improved bow that is compact, efficient, powerful, ergonomic, lightweight and is also distinct in appearance, operation and portability. 
         [0014]    Other and further objects, features and advantages will be evident from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein the examples of the presently preferred embodiments are given for the purposes of disclosure. 
         [0015]    In accordance with one aspect of the disclosed embodiments there is provided a projectile launching device (bow), comprising; a rigid riser; a hand grip operatively associated with said riser; at least one spring assembly operatively connected to said rigid riser, said spring assembly including a rotating member operatively associated therewith; a string operatively associated with said spring assembly such that each end of the bowstring is attached to the rotating member; a projectile releasably attached to said bowstring; and means to energize said spring assembly, where upon release of energy stored in said spring assembly said rotating member rotates and said bowstring to launches the projectile. 
         [0016]    In accordance with another aspect of the disclosed embodiments, there is provided an archery bow, comprising: a rigid riser; a hand grip operatively associated with said riser; at least one spring assembly operatively connected to said rigid riser, said spring assembly including a spring and a rotating member operatively associated therewith; a string operatively associated with said spring assembly such that each end of the bowstring is attached to the rotating member; an arrow releasably attached to said bowstring; and a pair of engaged spring cranks releasably connected to said spring assembly to energize said assembly and rotate said rotating member in a first direction, where upon release of energy stored in said spring said rotating member rotates in a second direction, opposite the first direction, applying increased tension to the bowstring and launching the arrow. 
         [0017]    In accordance with another aspect of the disclosed embodiments, there is provided a method for drawing and releasing a bow to propel an arrow, comprising: applying a linear drawing force to move a pair of engaged spring cranks, the cranks being releasably connected to a spring assembly, to energize said spring by rotating a member attached to said spring in a first radial direction; concurrently drawing a bowstring, with an arrow nocked thereto, said bowstring having each end thereof attached to the member; decoupling the spring assembly from the spring cranks; and releasing energy stored in said spring wherein said member rotates in a second direction, opposite the first direction, and said bowstring propels the arrow. 
         [0018]    Other and further objects, features and advantages will be evident from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein the examples of the presently preferred embodiments are given for the purposes of disclosure. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is an upright left side planar view of a bow having a pair of torsion spring assemblies in a relaxed position; 
           [0020]      FIG. 2  is an upright left side planar view of the bow of  FIG. 1  in a drawn position; 
           [0021]      FIG. 3  is a side view of an arrow socket; 
           [0022]      FIG. 4  is a cutaway view of the torsion spring assembly; 
           [0023]      FIGS. 5A-D  are isometric views of the torsion spring in various configurations; 
           [0024]      FIG. 6  illustrates a simplified vector-force diagram of the bow; 
           [0025]      FIG. 7  shows a planar view of a release mechanism; 
           [0026]      FIG. 8A  is a side perspective view of a single spring bow with cranks to assist in energizing the spring assembly; 
           [0027]      FIG. 8B  is a side view of a single spring bow in a static (undrawn) state; 
           [0028]      FIG. 8C  is a side view of a single spring bow in a dynamic (drawn) state; 
           [0029]      FIG. 9  is an isometric end view of a single spring bow; 
           [0030]      FIGS. 10 and 11  respectively depict an alternative embodiment of a single spring bow in a drawn and undrawn (relaxed) configuration; 
           [0031]      FIG. 12  is a partial perspective view illustrating an alternative design for several components of the bow depicted in  FIGS. 10 and 11 ; and 
           [0032]      FIG. 13  is an illustrative example of a method of using the device depicted in the various embodiments. 
       
    
    
       [0033]    The various embodiments described and depicted herein are not intended to limit the scope to those embodiments described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims. 
       DETAILED DESCRIPTION 
       [0034]    With particular reference to the drawings,  FIGS. 1 and 2  show an overview of one embodiment of the improved bow  100 . In this embodiment, an archery bow  100  includes a riser  102  providing a backplane for the mounting of the elements required to propel an arrow in a right handed archer configuration. Riser  102  is a rigid member and does not include leaves or similar flexural elements as in a conventional compound bow. In the embodiment of  FIGS. 1 and 2 , the riser includes an integral rearward hand grip  106  that is positioned midway between the extreme ends of the riser and likely somewhat below the horizontal center line of riser  102  so the arm of an archer is less likely to interfere with the arrow in the drawn position, as shown in  FIG. 2 . 
         [0035]    Associated with grip  106  is release trigger  140  ( FIG. 7 ) to releasably decouple the arms that energize spring assemblies  122  and  124  from the springs and permit the discharge of the arrow in the fully drawn position. It will be appreciated that various trigger mechanisms may be employed in place of the release trigger depicted in  FIG. 7 , however, such mechanisms should be capable of being actuated by a user&#39;s finger(s) or thumb. Moreover, it is also contemplated that the release mechanism may be associated with the archer&#39;s other (draw) hand, for example on hand grip  104 . Additionally, positioned just above grip  106  and situated substantially along the horizontal center line of riser  102  is arrow rest  114 , which serves as a support pad for arrow  112 . Any of a number of conventional arrow rests may be employed in accordance with the disclosed embodiments. 
         [0036]    Continuing to refer to  FIG. 1 , upper spring motor or assembly  122  is secured to the top end of riser  102 , likewise lower spring motor or assembly  124  is secured to the bottom end of the riser. While shown as in-line with riser  102 , the spring motors could alternatively be mounted perpendicular to the riser. Notably spring motors  122  and  124  are essentially identical in construction, albeit the motors operate in contrary rotational directions, specifically motor  122  when discharged rotates counterclockwise and conversely motor  124  rotates in a clockwise direction. 
         [0037]    Although generally depicted as torsion-type springs, the present disclosure further contemplates the use of alternative, spring-driven members that operate in a general rotational relationship relative to the riser. For example, the rotation of levers  118  and  120 , relative to riser  102  are depicted in  FIGS. 1 and 2  as being under the control of a torsion or wound spring  122 ,  124 . In an alternative embodiment, the torsion spring could be replaced with a tension or compression spring between the riser and levers to impart a similar spring force. Furthermore, the spring(s) themselves may be replaced with charged cylinders and piston assemblies (e.g., pneumatic, hydraulic) that similarly serve to store energy when the arms are moved and then provide for rapid release of the energy in order to transfer the energy from the “spring” to the bowstring and associated arrow or other projectile. 
         [0038]    The opposite ends of bowstring  116  are each cinched within a take-up lever by means of a loop inserted within a bifurcated end of the upper and lower bowstring take-up levers,  118  and  120  respectively. While levers  108  and  110  cause the bow to be energized, bowstring  116  is situated within arrow socket  128  by means of an interference fit, so as to remain taut, to remove slack from the string, while moving in unison with take-up levers  118  and  120  as they rotate to energize springs  132 . 
         [0039]    Referring also to  FIG. 3 , arrow nock  128  and bowstring  116 , in combination, are inserted and frictionally secured within arrow socket  128 , on hand grip  104 , by virtue of a receiving cavity, or similar opening, that provides a tendency force to predispose the arrow into a shooting position. In other words, arrow socket  128  will provide an adequate force to retain the arrow/bowstring in an aligned position while drawing the bow from rest yet allow arrow  112  to escape socket  128  by inertia, once the bow is fired and the arrow has been moved away from hand grip  104 . 
         [0040]    The arrow launching energy is generated by first rotating torsion spring  132  about pivot pin  134 , as viewed in  FIG. 4 , where one exposed end of the spring is operatively coupled to the riser  102  and the other exposed end of the spring is operatively coupled to the bowstring take-up lever (e.g.,  118 ,  120 ). As previously discussed the relative lengths of take-up lever  118  and the spring crank  108  provide the necessary mechanical advantage so as to significantly reduce the effort required by the archer to develop a high power launching force. The dual, but joined beam, depicted in  FIG. 6  shows a functional vector diagram of bow  100  having a relatively low vector force B translated to a relatively high vector force A. The force is thusly increased in the ratio of the forces A:B, which is approximately equal to the ratio of the distances to the fulcrum b:a. This ratio establishes the mechanical advantage, or the bow power index. Now, assume in  FIG. 5  that crank  108  and lever  118  are contiguous members having a fulcrum point  134  therebetween, and crank  108  is three times longer than lever  118 . Given the equation Force=(Mass) (Distance) and a 3:1 ratio, for example, a 30 pound force moving crank  108  a distance of 18 inches will yield an ultimate force of 90 pounds moving a distance of 6 inches or (30 lbs)(18 in)=(90 lbs)(6 in), neglecting any energy loss due to friction. Therefore, the present embodiment provides a means to accommodate the requirements of the archer by adjusting the “a” to “b” ratio by simply moving the fulcrum point or varying the length of a moment arm. 
         [0041]    Furthermore, to facilitate a smooth, but rapid transfer of energy to the arrow, take-up levers  118  and  120  may include a curvilinear profile whereby a cam like shape of the levers coincides with the power curve necessary to overcome inertia and provide a non-linear force to account for the acceleration of the arrow. This feature takes into consideration that an arrow at rest initially requires high energy/low velocity whereas in contrast a moving arrow needs a low energy/increasing velocity as it gains speed. The disclosed embodiments rely on the Laws of Motion to essentially regulate the power transfer in response to the reactive or resistive forces from the bow mechanics and the arrow. 
         [0042]    According to the disclosed embodiments an initial displacement force is applied by the user between forward hand grip  104  and rearward hand grip  106  providing an energy input into spring motor or assembly  122  that serves as a potential energy buffer or reservoir. The device intentionally requires that the energy to move the drawbar or handle  104  rearward requires a generally constant force over the range of movement from an at-rest position in front of the riser  102  (e.g.,  FIG. 1 ) to a fully drawn position rearward of riser  102  (e.g.,  FIG. 2 ). In other words, the generally continuous force requirement does not require or exhibit a let-off as one might experience in compound bows. Accordingly, as seen between  FIGS. 1 and 2 , crank  108  and  110  provide the energy input or energizing means and lever  118  and  120  the energy output means. As seen in  FIG. 4 , actuation of a release mechanism, such as release pin  138 , will disengage lever  118  from crank  108  and consequently convey an instantaneous force from spring  132  to bowstring  116  via take-up lever  118 . In one embodiment, the release of the energy from the torsion spring motor(s)  122  will only be possible when at full draw as the release mechanism will only work when the spring(s) is at full torque and has reached the full draw position. This feature is also unlike conventional re-curve and compound bows. Another advantage of the disclosed device is that it cannot be over-drawn because the arms are intentionally limited in the amount of draw (the included angle over which the arms travel from an at-rest to a fully drawn position). 
         [0043]    Other equivalent release mechanisms may include a ratchet, pawl, clutch and the like. In a similar manner lower spring motor  124  operates in accordance to the aforementioned specification in tandem with the upper spring motor  122 . An enabling aspect of the dual spring motor design is the ability to simultaneously release the stored spring energy; accordingly both release pins  138  are connected to a common actuator, and may have a synchronization adjustment to assure the coincident release by both spring motors. Also, as noted above, the release mechanism operates to prevent release unless the spring motors are at a fully-drawn state, thereby preventing the inadvertent release during draw or energizing of the spring. Referring to  FIG. 7 , a release trigger or similar mechanism  140  communicates with release pins  138  by upper and lower flexible cables  142  and  144  respectively. Trigger  140  is illustrated in the nature of a handle or lever, but it is understood that any mechanism suitable for actuation by a finger or thumb of the user when a hand is present on the handle  104  is also contemplated. In the illustrated embodiment, release trigger  140  is conveniently located adjacent rearward hand grip  106  so it may be actuated with minimal impact upon launching of arrow  112  and not offset the absolute aim point. It is noted that releasing spring motors  122  and  124  out of phase may by and large impart adverse dynamics into the flight trajectory of the arrow. Accordingly, release equalizer  146  provides for a balancing adjustment to make certain that the release is simultaneous. 
         [0044]    Spring motor  122 , in the embodiment depicted in  FIG. 4 , comprises a helical torsion spring as seen in  FIGS. 5A-D , that encircles pivot pin  134 , and exerts a torque or rotary force. In one embodiment, torsion spring  122  may be formed from 17-7 PH Stainless Steel having a diameter of about 0.283 in., and seven coils. The wire coil has a diameter of about 0.880 in. and a leg length of about 2.5 in. legs. The approximate weight of the torsion spring is 0.56 lbs. The springs may be fabricated according to custom requirements for orientation, spring force, torque, etc. One leg of torsion spring  132  is attached to riser  102  and held stationary while the opposite leg follows the rotational motion of take-up lever  118 . It will be appreciated that alternative spring configurations and particularly alternative spring designs may be employed in accordance with aspects of the disclosed device. Spring crank  108 , during the energizing cycle, is disengageably connected to both spring  132  and take-up lever  118  by means of release pin  138 , as depicted in functional  FIG. 6 , and they are pivotally disengaged from one another during the firing cycle. For all intents and purposes lower spring motor  124  operates in substantially the same manner, except spring  132  is wound in the opposite direction as viewed in  FIG. 5 . 
         [0045]    In one embodiment the spring leg attachment point to riser  102  is adjustable to enable the pre-loading of spring motor  122  with an initial force. A torsion spring constant is measured by in-lbs/deg. deflection, therefore a quiescent spring provides a zero force. The primary objective of pre-loading is to establish an offset so as to shift the range of force, for example, given a spring constant of 0.5 in-lbs/deg, the force varies from 0 to 45 lbs over a 90-degree deflection. Given the same spring with a 10 degree offset or “preload,” the force range is 5 to 95 lbs. Again, as discussed above, with adjustable moments and also a variable load offset adjustment, the disclosed bow embodiments are readily adaptable to an archer&#39;s various attributes of size, strength and skill. 
         [0046]    Referring to  FIGS. 8A-C  and  9 , in an alternative embodiment, a central spring is substituted for the two outboard springs described above. Various aspects of this configuration are seen in  FIGS. 8A-C  where the spring is wound using dual levers  108  and  110  moving in unison to turn a single rotating member  121  to which the ends of bowstring  116  are attached. The inherent advantage of this embodiment is having the arrow launching energy derived from a single source thereby reducing or eliminating the need to assure spring motor synchronization, hysteresis and inertia. The fundamental operation remains the same in the embodiment depicted in  FIGS. 8A-C  and  9 , whereby a torsional spring  132  is energized, using levers  108  and  110 , decoupled from rotating member  121  by releasing trigger  140  and thereby placing bowstring  116  in tension so as to propel arrow  112 . 
         [0047]    Referring to  FIGS. 8B and 8C  and the above discussion relative to a single spring motor device, both levers  110  and  108  respectively are eliminated, and bowstring  116  is directly attached to rotating member  121  and thereby to associated torsion spring  132 . Rotating member  121  still provides a mechanical advantage to energize spring  132  through a moment arm that is defined by the path of bowstring  116  as rotating member  121  rotates as arrow  112  is drawn into a firing position. For example, if bowstring  116  follows the perimeter of member  121  a uniform rotational displacement occurs from about 0 to about 90 degrees. However, it is possible to alter the displacement by having a variable distance or moment between bowstring  112  and the axis of rotating member  121 . For example rotating member  121  may be eccentrically shaped or mounted so as to act like a cam as bowstring  116  is moved, thereby modifying the force required to pull the bowstring. As previously mentioned the intrinsic advantage of having the arrow launching energy derived from a single spring motor eliminates the potential problem with synchronizing the operation of a pair of springs. While the embodiment of  FIGS. 8B and 8C  further eliminates levers  108  and  110 , the mass associated with the embodiment, and possibly the system inertia, is significantly decreased and the overall design is appreciably simplified. Furthermore, as contrasted with the earlier embodiment, it is clear that several alternative means (levers, bowstring, etc.) for energizing the spring may be employed in the various embodiments. 
         [0048]    Referring now to  FIGS. 10 and 11 , depicted therein is another alternative embodiment for the projectile launching device  100  shown, respectively, in a drawn and undrawn configuration. The device  100  comprises a rigid riser  102  including an adjustable forward hand grip  104  operatively associated with said riser. In the embodiments depicted, the adjustable hand grip may be moved along handle guide member  148 , which itself is affixed to riser  102 . Hand grip  104  may be adjusted using a series of mounting holes (see  FIG. 12 ), or using a conventional clamping arrangement (e.g., a through screw is placed within a longitudinal slot and is tightened with a bolt on the back) to attach the hand grip in a desired position based upon the size of the user (e.g., arm length, draw length). The device also includes at least one spring assembly that includes a spring (e.g., torsion, compression, tension, pressurized cylinder) operatively connected to said rigid riser, the spring assembly also including a rotating member  121  operatively associated with the spring. As in the previous embodiments member  121  rotates or pivots between a neutral (undrawn) position where little or no force is on the member, and a rotated position (approximately about 90-degrees) where the spring assembly is ready to apply force to the bowstring  116  operatively associated with the spring assembly. In one embodiment, each end of the bowstring is attached to the rotating member such that when the member is released a large tensile force is applied to the bowstring. As described above, the bow  100  depicted in  FIGS. 10 and 11  may similarly include a trigger  140  associated with the handle  104  (or 106) and a release mechanism, such as release pin (not shown), that will disengage member  121  from crank  108  and consequently convey an instantaneous force from the spring  132  to the bowstring  116 . In one embodiment, the release of the energy from the torsion spring will only be possible when at full draw (approx. 90-degree rotation of the torsion spring and member  121 ), as the release mechanism may be designed to only work when the spring is at full torque and has reached the full draw position. This feature is also unlike conventional re-curve and compound bows. Another advantage of the disclosed device is that it cannot be over-drawn because the crank arms  108  and  110  are intentionally limited in the amount of rotation by the toothed sections thereof (teeth covering only slightly greater than 90-degrees of arc). As noted with respect to the release mechanism described for the other embodiments, the current embodiment contemplates the use of alternative but equivalent mechanisms such as a ratchet, pawl, clutch and the like. 
         [0049]    Once a projectile such as arrow  112  is releasably attached to the bowstring via nock  128 , a means to energize the spring assembly is used to rotate the member to store energy in the spring assembly. In one embodiment, the means to energize the spring assembly includes crank arms  108  and  110  which are pivotally connected to draw link members  156  and handle  106 . By pulling rearward handle  106  away from handle  104 , the user is able to rotate member  121  and thereby energize the spring assembly. The crank members move in a coordinated manner as each is in contact with and engages the other via a plurality of teeth located along a portion of the curved periphery of the crank members to form sector gear  147 . It will be appreciated that other means may be employed to keep cranks  108  and  110  in contact with each other including contact, belt/pulley, etc. In the depicted representation, draw link members  156  are if a generally rigid material, however an alternative embodiment contemplates the use of a flexible cable or the like as the draw link members. 
         [0050]    As discussed previously, instead of the cranks and draw links, it is also possible to use the bowstring itself as the means to energize the spring assembly. In such an embodiment, there would be no mechanical advantage gained through the cranks, but it would reduce the mechanical complexity and cost of the device. As noted above, a trigger such as release handle  140  in conjunction with a release cable  136  are used to control the release of the release pin  138  that provides the interconnection between crank  108  and torsion spring assembly  132 . When pulled into a drawn position, the trigger may be activated and upon release of energy stored in the spring assembly the rotating member  121  rotates and the bowstring launches the projectile, arrow  112 . 
         [0051]    Referring also to  FIG. 12 , depicted therein are components of an alternative embodiment to that depicted in  FIGS. 10 and 11 , including an integrated, T-shaped riser with handle guide as member  170 . Member  170  includes a vertical portion having rollers  150  on the top and bottom ends, and a horizontal portion with an adjustable handle  104  attached thereto. The location of handle  104  may be adjusted in the direction of reference arrow  176  using a plurality of differently spaced holes (not shown) that correspond with the pattern of four screws  180  illustrated in the figure. In such a configuration the bow is adjustable to fit various users by adjusting the relative distance between the bowstring (not shown in  FIG. 12 ) and the forward handle  104 . In addition, an arrow rest and/or target sighting devices may also be attached to the member  170  or the handle  104 . In one embodiment, an optional shield  186  may be added to member  170 , where shield  186  extends outward and over the arm of the user, thereby shielding the user from the arrow itself, or arrow fragments in the event the arrow is damaged during launch. Shield  186  may be attached to or integrally formed with member  170 , and may be of a metal or composite material suitable for providing a protective shield. 
         [0052]    Turning next to  FIG. 13 , depicted therein is a flowchart illustrating the general steps in operation of a device such as that discussed above. In a general sense, the method for drawing and releasing a bow to propel an arrow, includes, after nocking the arrow ( 200 ), applying a linear drawing force to move a pair of engaged spring cranks, the cranks being releasably connected to a spring assembly, to energize a spring by rotating a member attached to the spring in a first radial direction ( 210 ), and concurrently drawing a bowstring, with a nocked arrow. The bowstring has each end thereof attached to the rotating member. After drawing the cranks and knocked arrow together, and reaching a fully drawn position at  220 , the spring assembly may be decoupled from the spring cranks ( 230 ), thereby releasing energy stored in the spring ( 240 ). Upon release the rotating member rotates in a second direction, opposite the first direction, and the force applied to the bowstring propels the arrow. Completing the firing cycle, the crank arm is moved back into the relaxed (undrawn) position until a pawl or pin is again engaged to create the connection between the crank and rotating member, thereby preparing for a subsequent drawing of the bowstring and spring assembly ( 250 ). 
         [0053]    It will be appreciated that various of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.