Patent Publication Number: US-6990970-B1

Title: Compound archery bow

Description:
This application claims priority from application Ser. No. 60/498,122 filed Aug. 27, 2003. 

   The present invention is directed to compound archery bows having pulleys at the ends of the bow limbs to control the force/draw characteristics of the bow, and more particularly to both single-cam bows having a power let-off cam mounted on the end of one of the bow limbs and dual-cam bows having power let-off cams mounted on the ends of both bow limbs. 
   BACKGROUND AND SUMMARY OF THE INVENTION 
   Single-cam and dual-cam compound archery bows have power cams mounted on one or both ends of the bow limbs to control the draw force on the bowstring and the bending of the limbs as the bowstring is drawn. In single-cam bows, there is a power cam on the end of one bow limb, and a wheel on the end of the other bow limb to control or time take-up of a power cable at the power cam and let-out of the bowstring and control cables at the power cam as the bow is drawn. In dual-cam bows, power cams are mounted on the ends of both bow limbs, with each including groove segments to control let-out of the bowstring cable at the opposing cam. In conventional single-cam and dual-cam bows or crossbows, the power cables or cable segments are anchored near the end of one or both bow limbs, at the axles in most cases. 
   Briefly stated, in accordance with the presently preferred embodiments of the invention, the power cable or cable segment is anchored not to the end of a bow limb, but is trained around additional let-out means in the cam or control wheel at the end of the bow limb. This additional let-out means decreases limb movement as the power cam takes up the power cable during the power stroke, and allows the design of the power cam take-up groove to be larger and thereby facilitate use of larger radii in designing the cable path to reduce fatigue of the power cable. The additional let-out means also facilitates bow designs with increased pre-stress in the bow limbs while minimizing movement of the limbs during the power stroke, thereby reducing limb shock and increasing efficiency. This additional let-out means also facilitates additional control of the cam and/or cam wheel rotation between the upper and lower limbs because the additional cross-coupling forces the rotation to be in unison. As applied specifically to dual-cam bows and crossbows with draw stops on one or both cams, the invention permits continued rotation at both cams until the draw stops are engaged at both cams. 
   A compound archery bow in accordance with a first aspect of the invention includes a handle having projecting limbs. (The term “compound archery bow,” as employed in this application, encompasses both compound traditional bows (e.g.,  FIGS. 1–19 ) and compound crossbows (e.g.,  FIGS. 20–22A ).) A first pulley is mounted for rotation around a first axis on a first of the limbs, and a second pulley is mounted for rotation around a second axis on a second of the limbs. In single-cam bows, one of the pulleys is a control wheel and the other pulley is a power cam. In dual-cam bows, the pulleys are respective power cams. A bow cable arrangement extends between the pulleys, and includes a bowstring cable extending from bowstring let-out grooves in the first and second pulleys so that, as the bowstring cable is drawn away from the handle, the bowstring cable lets out or unwraps from the bowstring grooves and rotates the pulleys around the respective axes. 
   First and second cables extend from cable take-up grooves on the respective pulleys to first and second cable let-out means on the respective opposite pulleys. Thus, as the bowstring cable is drawn away from the handle, the first and second cables are each taken up or wound at one end onto one of the pulleys and let out or unwound at the other end from the other pulley. The let-out means preferably comprises at least one groove from which the cable is let-out or unwrapped as the cable is drawn. This let-out groove preferably is circular and concentric with the axis of pulley rotation but can be non-circular and/or non-concentric with the axis of rotation. In some embodiments, the let-out grooves are disposed on opposite sides of the bowstring let-out groove for improved balance. The let-out means alternatively may comprise one or more posts mounted on the pulley and offset from the axis of pulley rotation. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, together with additional objects, features, advantages and aspects thereof, will be best understood from the following description and the accompanying drawings, in which: 
       FIG. 1  is a side elevational view of a single-cam compound archery bow in accordance with one presently preferred embodiment of the invention, and  FIGS. 2 and 3  are fragmentary elevational views taken substantially from the respective directions  2  and  3  in  FIG. 1 ; 
       FIGS. 1A ,  2 A and  3 A are views respectively similar to those in  FIGS. 1 ,  2  and  3  but illustrating a modification to the embodiment of  FIGS. 1–3 ; 
       FIG. 4  is a side elevational view of a dual-cam bow in accordance with another preferred embodiment of the invention, and  FIGS. 5 and 6  are fragmentary elevational views taken from the respective directions  5  and  6  in  FIG. 4 ; 
       FIGS. 4A ,  5 A and  6 A are views respectively similar to those in  FIGS. 4 ,  5  and  6  but illustrating a modification to the embodiment of  FIGS. 4–6 , and  FIG. 6B  is a fragmentary elevational view taken substantially from the direction  6 B in  FIG. 5A ; 
       FIG. 7  is a side elevational view of a dual-cam bow in accordance with yet another presently preferred embodiment of the invention, and  FIGS. 8 and 9  are fragmentary elevational views taken substantially from the respective directions  8  and  9  in  FIG. 7 ; 
       FIG. 10  is a fragmentary elevational view that illustrates a modification to the bow of  FIGS. 1–3 , and  FIG. 11  is an elevational view taken from the direction  11  in  FIG. 10 ; 
       FIGS. 10A and 11A  are elevational views similar to those in  FIGS. 10 and 11  but illustrating a modification to the embodiment of  FIGS. 10–11 ; 
       FIGS. 12 and 13  are opposing fragmentary side elevational views of a dual-cam bow in accordance with another embodiment of the invention, and  FIGS. 14 and 15  are fragmentary elevational views taken from the respective directions  14 ,  15  in  FIG. 12 ; 
       FIG. 16  is a side elevational view of a single-cam bow in accordance with another embodiment of the invention, and  FIG. 17  is a fragmentary elevational view taken from the direction  17  in  FIG. 16 ; 
       FIGS. 16A and 17A  are elevational views that are respectively similar to those in  FIGS. 16 and 17  but illustrate a modification to the embodiment of  FIGS. 16–17 ; 
       FIG. 18  is an elevational view that compares cam-base peripheries in a dual-cam bow modification to the embodiment of  FIGS. 12–15 ; 
       FIG. 19  is a fragmentary elevational view that illustrates another modification to the bow of  FIGS. 12–15 ; 
       FIG. 20  is a top plan view of a crossbow that embodies the principles of the present invention, and  FIGS. 21 and 22  are top plan and side elevational views of the crossbow front assembly in the crossbow of  FIG. 20 ; 
       FIGS. 20A ,  21 A and  22 A are views respectively similar to those in  FIGS. 20–22  but illustrating a modification to the embodiment of  FIGS. 20–22 , and  FIG. 20B  is a bottom plan view of the bow in  FIGS. 20A–22A . 
       FIGS. 23–26  are fragmentary elevational views that illustrate respective further embodiments of the invention; and 
       FIG. 27  is an elevational view of the draw length adjustment module in the bow of  FIG. 16 ,  FIG. 28  is a fragmentary elevational view of a power cable engaging the draw stop in the module of  FIG. 27 , and  FIGS. 29 and 30  are opposed end views of the module in  FIG. 27 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1–3  illustrates a single-cam compound archery bow  30  in accordance with one presently preferred embodiment of the invention as comprising a handle  32  of aluminum or other relatively rigid construction having spaced risers  34 ,  36  with a limb-mounting surface at each end. A pair of flexible resilient limbs  38 ,  40  of fiber-reinforced resin or other suitable resilient construction are mounted on respective handle risers  34 ,  36  and project away from handle  32 . A control wheel  42  is mounted on an axle  44  that extends laterally across the free end of bow limb  38 , such that control wheel  42  is mounted for rotation around a first axis within an open space or bracket at the free end of limb  38 . Likewise, a power cam  46  is mounted on an axle  48  that extends laterally across the free end of limb  40 , such that power cam  46  is mounted for rotation around a second axis within a notch or bracket at the free end of limb  40 . Control wheel  42  and power cam  46  may be rotatable on axles  44 ,  48 , or the axles may be secured to the control wheel and/or power cam and rotatable on the limbs. The positions of control wheel  42  and power cam  46  can, of course, be reversed. 
   A control cable CC is anchored at one end to control wheel  42  and at an opposing end to power cam  46 . Likewise, a bowstring cable BSC is anchored at opposing ends to control wheel  42  and power cam  46 . An arrow is to be nocked on bowstring cable BSC between control wheel  42  and power cam  46 . Power cam  46  comprises a cam base  52 , which preferably although not necessarily has a draw-length adjustment module  54  mounted thereon with a take-up groove to load the opposite limb through power cable PC. Power cam  46  is similar to a cam illustrated in U.S. Pat. No. 6,516,790, the disclosure of which is incorporated herein by reference for further discussion of the power cam assembly and operation of the overall bow. A power cable PC is anchored at power cam  46  and extends across bow  30  to control wheel  42 . Control wheel  42  has a pair of pulleys  49 ,  50  disposed on laterally opposed sides of the control wheel. Pulleys  49 ,  50  may be formed integrally with control wheel  42 , or may be separately made and pinned or otherwise secured to the control wheel. The end of power cable PC is split at PC 1 , PC 2 , and the split ends of the power cable are wound around pulleys  49 ,  50  respectively. (In the embodiment of  FIGS. 1A–3A , a single pulley  49   a  combines the functions of pulleys  49 ,  50  in  FIGS. 1–3 , and power cable PC is not split and is wound around pulley  49   a .). The split ends PC 1 , PC 2  of the power cable are anchored at  53  to control wheel  42 . The peripheral power cable let-out grooves in pulleys  49 ,  50  preferably are circular and concentric with the axis of rotation at axle  44  as illustrated in  FIGS. 1–3 , but can be non-circular and/or non-concentric with the axis of control wheel rotation. 
   Control wheel  42  has a single circular or non-circular peripheral groove  56  with a center or axis that preferably is offset from the axis of axle  44 . Peripheral groove  56  lies in a plane that is perpendicular to the axis of axle  44 . Bowstring cable BSC extends clockwise (in  FIG. 1 ) around the periphery of groove  56  and is anchored to control wheel  42  at a post  58 . Control cable CC extends at wheel  42  counterclockwise through a small tangential portion of groove  56  (in the rest position of the bow and the orientation illustrated in  FIG. 1 ), and is anchored to control wheel  42  at a post  60 . There thus is a gap in peripheral groove  56  through which cables BSC and CC extend to respective anchor posts  58 ,  60 , which are mounted to the body of the control wheel inwardly of the gap. As a modification to the embodiment illustrated in  FIG. 1 , control cable CC and bowstring cable BSC may comprise a single length of cable that is suitably anchored to the control wheel. 
   Thus, as bowstring cable BSC is drawn, the effective radius of groove  56  from axle  44  continuously changes. Both the bowstring cable and the control cable travel in groove  56 . The bowstring cable is let out as the bow is drawn, and the control cable is taken up in the same groove. At some point, the control cable may enter a segment of the groove that previously was occupied by the bowstring cable in the rest position of the bow. The control wheel configuration illustrated in  FIG. 1  provides more control of the let-out of the bowstring while maintaining better control of nock point travel and making it easier to achieve more stored energy in the bow. Wrapping into and unwrapping from a single peripheral groove at the periphery of control wheel  42  also reduces torsional stresses on the axle that would otherwise be associated with wrapping into and unwrapping from laterally adjacent grooves on the control wheel. The additional power cable let-out grooves at pulleys  49 ,  50  on both sides of the central control wheel groove  56  accomplishes the objectives of the invention set forth above, and gives improved limb balance and timing control. Groove  56 , which is the take-up groove for cable CC (as well as the let-out groove for cable BSC) preferably is non-circular. Disposition of cables PC 1  and PC 2  in let-out grooves on opposite sides of groove  56  balances the forces applied to axle  44  and reduces torsion in limb  38 . 
     FIGS. 4–6  illustrate a dual-cam compound archery bow  60  in accordance with another embodiment of the invention. Power cams  62 ,  64  are mounted by corresponding axles  66 ,  68  at the ends of respective bow limbs  38 ,  40 . A bowstring cable BSC extends between let-out grooves  72 ,  78  on the respective cams  62 ,  64 . A first control/power cable CPC 1  extends from a take-up groove  70  on power cam  62  to a let-out groove  74  on a pulley  76  at power cam  64 . Likewise, a second control/power cable CPC 2  extends from a take-up groove  72  at power cam  64  across bow  60  to a let-out groove  80  on a pulley  82  secured to power cam  62 . Cables CPC 1 , CPC 2  are anchored at  84 ,  86  to pulleys  76 ,  82  respectively. As in the embodiment of  FIGS. 1–3 , the grooves  74 ,  80  of pulleys  76 ,  82  are circular and concentric with the respective axes of rotation at axles  68 ,  66 , but may be non-circular and/or non-concentric if desired. Disposition of cables CPC 1  and CPC 2  in grooves  70 ,  80  on opposite sides of groove  72  at cam  62 , and in grooves  72 ,  74  on opposite sides of groove  78  at cam  64 , reduces torsion on limbs  38 ,  40 . 
     FIGS. 4A ,  5 A,  6 A and  6 B illustrate a bow  60   a  having power cams  62   a ,  64   a . In the power cams of  FIGS. 4A ,  5 A,  6 A and  6 B, the bowstring let-out grooves  72 ,  74  are on one side of the cams, rather than being positioned in the middle of the cams in  FIGS. 5 and 6 . Let-out groove  80  for cable CP 2  is positioned on the opposing side of cam  62   a , and take-up groove  70  for cable CP 1  on cam  62   a  is positioned between grooves  72 ,  80 . Likewise, let-out groove  74  for cable CP 1  at cam  64   a  is positioned on a side of cam  64   a  opposite bowstring let-out groove  74 , and take-up groove  72  for cable CPC 2  at cam  64   a  is positioned between grooves  74 , 78 . As shown in  FIG. 6B , cable CPC 1  is anchored at  86  at cam  62   a  after passing around an adjustable draw length module  87 , and cable CPC 2  is anchored at  180  on pulley  82   a . Bowstring cable BSC is anchored at  182  on base  184  of cam  62   a.    
     FIGS. 7–9  illustrate a dual-cam bow  90  in accordance with a further embodiment of the present invention. Power cam  62  at the end of bow limb  38  is the same as power cam  62  in embodiment of  FIGS. 4–6 . In the embodiment of  FIGS. 4–6 , power cam  64  is the mirror image of power cam  62 . However, in the embodiment of  FIGS. 7–9 , power cam  92  at the end of bow limb  90  is identical to power cam  62  at the end of bow limb  38 . As a result, as best seen in  FIGS. 8 and 9 , control/power cables CPC 1  and CPC 2  do not cross each other at the center of the bow, as they do in  FIGS. 5 and 6 , and the arrow is shot from bowstring cable BSC between the control/power cables. This cable configuration allows the bow to be set up with or without cable guards. Otherwise, operation of the embodiment of  FIGS. 7–9  is the same as in  FIGS. 4–6 . 
     FIGS. 10 and 11  illustrate a modification to the embodiment of  FIG. 1 , in which the control wheel or pulley  100  at the end of bow limb  38  has a pair of peripheral grooves  56 ,  102  at relatively large diameter coaxial and concentric with axle  44 , and a pair of side pulleys  49 ,  50  with peripheral let-out grooves also concentric and coaxial with axle  44 . Ends PC 1 , PC 2  of power cable PC are wound in the peripheral grooves of pulleys  49 ,  50 . Control cable CC is wound into take-up pulley groove  102 , while bowstring cable BSC is wound out of let-out pulley groove  56 . Thus, as bowstring cable BSC is drawn (to the left in  FIG. 10 ), the bowstring cable is unwound from groove  56 , while power cable ends PC 1 , PC 2  are unwound from pulleys  49 ,  50  and control cable CC is wound into pulley groove  102 . As in the other embodiments, pulleys  49 ,  50  may be made as one piece with the wheel  100  that includes grooves  56 ,  102 , or may be fabricated separately and pinned or otherwise secured to the larger wheel. Pulleys  49 ,  50  may be non-circular and/or non-concentric with axle  44 , if desired.  FIGS. 10A and 11A  illustrate a modification to the embodiment of  FIGS. 10 and 11  in which the separate pulleys  49 ,  50  of  FIGS. 10 and 11 , are combined into a single pulley  49   a , and power cable PC is wrapped around pulley  49   a  and not split. 
     FIGS. 12–15  illustrate a dual-cam bow  110  having cams  112 ,  114  mounted at the respective ends of bow limbs  38 ,  40 . Cams  110 ,  114  preferably are mirror images of each other in this embodiment. In this embodiment, control/power cable CPC 1  is wound around a peripheral let-out groove in a pulley  76  on cam  114 , and is anchored at  116  to the cam base  118 . Likewise, control/power cable CPC 2  is wound around a peripheral let-out groove in a pulley  82  on cam  112  and anchored at  120  to cam base  122 . Each cam  112 ,  114  has a take-up groove or a draw-length module  124 ,  126  mounted on the associated cam base  122 ,  118 . Control/power cable CPC 1  engages a peripheral take-up groove on draw-length module  124 , and is anchored at  128  to cam base  122 . Likewise, control/power cable CPC 2  engages a peripheral take-up groove on draw-length module  126 , and is anchored at  130  to cam base  118 . Each draw-length module  124 ,  126  includes an associated draw stop  132 ,  134  that engages the associated control/power cable when the bow is fully drawn—i.e., when the associated control/power cable is fully taken up into the associated draw-length module peripheral groove. An advantage of this embodiment of the invention lies in the fact that, if cams  112 ,  114  are not perfectly timed, draw of bowstring cable BSC may continue from both cams until both draw stops engage the associated control/power cables. 
     FIGS. 16 and 17  illustrate a single-cam bow  140  that has a power cam  142  at the end of bow limb  40  and a control wheel  144  at the end of limb  38 . Power cam  142  is similar to cam  46  discussed in connection with  FIGS. 1–3 . Control wheel  144  has a peripheral bowstring cable let-out groove  56 , and a peripheral control cable take-up groove  146 . Power cable let-out pulleys  49 ,  50  have associated peripheral grooves that receive the split ends PC 1 , PC 2  of power cable PC. The power cable ends are anchored to the opposed sides of the base of control wheel  144 , as illustrated at  148  in  FIG. 16 . Thus, as bowstring cable BSC is drawn to the left in  FIG. 16 , bowstring cable BSC is let out of groove  56  on control wheel  144  and an associated groove on power cam  142 , and power cable PC is let out of the peripheral grooves of pulleys  49 ,  50 . Control cable CC is taken up into the groove  146  on control wheel  144 , and let out from power cam  142 . The power cable PC that is let out from pulleys  49 ,  50  is taken up at power cam  142 .  FIGS. 16A ,  17 A show a modification to the embodiment of  FIGS. 16 and 17 , in which pulleys  49 ,  50  are combined into a single pulley  49   a , around which non-split power cable PC is wrapped. 
     FIG. 18  illustrates a modification to bow  110  illustrated in  FIGS. 12–15 .  FIG. 18  compares the periphery of cam base  118  of lower cam  114  to periphery of cam base  122   a  of upper cam  110 . As can be seen in  FIG. 18 , cam base  122   a  has a periphery that is a greater distance from the axis of rotation  150  for most but not all of the peripheries of the cam bases. The upper cam thereby lets out more cable BSC than the lower cam as the cams simultaneously rotate and the bowstring is drawn. This keeps the center portion of the bowstring, to which the arrow is nocked, parallel with the bow handle, and obtains straight-line nock travel that does not slope upwardly or downwardly with respect to the bow handle if the arrow is not drawn from the center of the bow. The bow  30  of  FIGS. 1–3  and the bow  140  of  FIGS. 16–17  could be modified by providing a second power cable PC, a second power cable take-up groove on the opposite side of power cam  46  or  114 , and thus employing parallel power cables instead of a single split power cable as illustrated in those drawings. 
     FIG. 19  illustrates a bow  160  that is a modification to the bow  110  illustrated in  FIGS. 12–15 . In the bow  160 , the lower cam  114  is the same as in  FIGS. 12–15 , while the upper cam  112   a  is similar to cam  112  but does not include a draw stop ( 132  in  FIG. 13 ). This modification takes advantage of the fact that the system eliminates the problem of timing between the upper and lower cams, and the problem of non-linear nock travel if one draw stop is engaged on one cam but not on the other. 
     FIGS. 20 ,  21  and  22  illustrate a crossbow  170  that embodies the principles of the present invention, particularly as illustrated in the embodiment of  FIGS. 4–6 . Elements in the crossbow  170  of  FIGS. 20–22  that correspond to the elements of the bow  60  in  FIGS. 1–6  are indicated by correspondingly identical reference numerals followed by the suffix “b.” The stock  172  and the trigger mechanism  174  preferably are as illustrated in U.S. Pat. No. 5,884,614. The crossbow alternatively could embody the cam and control wheel configurations illustrated in any of the other drawing figures. 
     FIG. 20A  is a top plan view of a crossbow  200  in accordance with another embodiment of the invention,  FIG. 20B  is a bottom plan view of the crossbow  200 , and  FIGS. 21A and 22A  show the crossbow front assembly  202  in the crossbow  200 . Elements in  FIGS. 20A ,  20 B,  21 A and  22 A that are similar to those in  FIGS. 20–22  are indicated by correspondingly identical reference numerals with the suffix “c”. Bow  200  has a pair of power cams  204 ,  206  mounted on the ends of the respective bow limbs  38   c ,  40   c . Cams  204 ,  206  are mirror images of each other. In cam  204 , bowstring cable BSCc is wound around a peripheral groove on a cam base  208 , which has a circular peripheral groove that is eccentric to the axle  210  on which cam  204  is mounted to bow limb  38   c . Control power cable CPC 1   c  is wound around the circular peripheral groove on a pulley  212  and anchored at  214  to base  208 . Cable CPC 2   c  is wound around a pulley  216  and anchored at  218 . Pulley  216  has a circular peripheral groove that is concentric with axle  210 . The circular peripheral grooves of pulley  212  and base  208  are eccentric to axle  210  and to each other. The mirror image of this arrangement is provided at cam  206 , with cable CPC 2   c  being anchored at  214   a  on base pulley  208   a , bowstring cable BSCc being trained around base pulley  208   a  and anchored at  209   a , and cable CPC 1   c  being trained around pulley  216   a  and anchored at  218   a . Pulleys  208 ,  212 ,  216  (and pulleys  208   a ,  212   a  and  216   a ) preferably are constructed as a single unit. 
     FIGS. 23–26  illustrate respective modifications to the embodiment of  FIGS. 4A ,  5 A,  6 A and  6 B, for example, in which the power/control cable let-out means comprises one or more posts secured to the pulley offset from the axis of rotation. In  FIG. 23 , for example, control/power cable CPC 2  is anchored to a post  230  on cam base  232  at a position offset from axle  234  that defines the axis of rotation. As bowstring cable BSC is drawn (to the right in  FIG. 23 ), pulley  236  rotates clockwise around axle  234  and cable CPC 2  is let out from the pulley. At the extreme end of bowstring cable draw, as post  230  moves beneath axle  234  and back up, cable CPC 2  may be taken up. In the pulley  236   a  of  FIG. 24 , cable  238  extends to post  230  around an intermediate post  238 . In pulley  236   b  of  FIG. 25 , cable CPC 2  extends to post  230  around two angularly spaced intermediate posts  238 ,  240 . In pulley  236   c  of  FIG. 26 , cable CPC 2  extends to post  230  around three angularly spaced intermediate posts  238 ,  240 ,  242 . The intermediate posts reduce or eliminate the amount of cable CPC 2  taken up at the end of the draw stroke. 
     FIGS. 27–29  illustrate draw length module  54  ( FIG. 1 , or  87  in  FIG. 6B , or  124 ,  126  in  FIG. 13 ) in greater detail. A draw stop  250  extends from module  54  for abutment with power cable PC (or cables CPC 1 , CPC 2  in  FIGS. 12–14 ). In bows having a cable guard  252  ( FIG. 1 ) cable PC (or cable CPC 1  in  FIG. 6B , or CPC 1 , CPC 2  in  FIG. 13 ) extends at an angle from let-out groove  254  on module  54 —i.e., at an angle to the plane of the draw length module as shown in  FIG. 28 . In accordance with a further aspect of the invention, the cable abutment surface  256  of draw stop is concave and angled (see  FIG. 29 ) to maintain cable PC 1  (or CPC 1  or CPC 2 ) in groove  254  at the extreme end of cable draw. 
   There thus has been disclosed a compound archery bow that fully satisfies all of the objects and aims previously set forth. The invention has been disclosed in conjunction with several presently preferred embodiments thereof, and additional modifications and variations have been discussed. Other modifications and variations will readily suggest themselves to persons of ordinary skill in the art in view of the foregoing discussion. The invention is intended to embrace these and all other modifications and variations as fall within the spirit and broad scope of the appended claims.