Abstract:
A highly versatile exercise apparatuses is disclosed. More particularly, the invention relates to an exercise apparatus including a central weight stack and opposed extension arms. Upper and lower pulleys direct a cable into the opposed extension arms such that variations in the cable reaction and tension are minimized when either arm is moved.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation-in-part of U.S. patent application Ser. No. 10/261,546 filed on Sep. 30, 2002 now abandoned, entitled “Cable Crossover Exercise Apparatus”, inventor Roy Simonson, which is a continuation of U.S. patent application Ser. No. 09/864,246 filed on May 25, 2001, entitled “Cable Crossover Exercise Apparatus”, inventor Roy Simonson, now U.S. Pat. No. 6,458,061, which is a continuation of U.S. patent application Ser. No. 09/395,194, filed on Sep. 14, 1999, entitled “Cable Crossover Exercise Apparatus”, now U.S. Pat. No. 6,238,323, each of which is incorporated herein in its entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is in the field of cable crossover exercise apparatuses having a central weight stack and opposed extension arms. 
     2. Description of Related Technology 
     Exercise apparatuses commonly employ a weight stack actuated by a cable which is pulled by users of the apparatus. Some of such arrangements can present certain limitations affecting the usefulness of the exercise apparatus. For example, the range of exercises which may be performed with certain cable actuated apparatuses is sometimes limited by the effective length of cable linking the weight stack with the user. The effective useful length of the cable may be limited by the height of the weight stack; in such systems, for example, for each foot the cable is pulled by the user, the weight stack may be required to rise a proportional distance. Where the rise of the weight stack is substantially equal to the distance which the cable is pulled, the effective useful length of the cable is often limited to only a few feet since building weight stacks any larger can be cost prohibitive, or structurally undesirable. 
     Certain weight stack based exercise apparatuses also encounter problems as a result of the momentum created when the weight plates are lifted under the control of a cable. Specifically, when the weight plates are lifted upwardly at a fast pace, the generated momentum can create momentary reductions and increases in the perceived force encountered by the user. Such momentary changes are highly undesirable. 
     Some weight stack based exercise apparatuses also encounter problems with the cable catching or binding on the frame, support arms, or other parts of the assembly. Certain weight stacks also have cables that shorten or lengthen when a support arm(s) that contacts the cable moves upward or downward. Such shortening or lengthening can cause the handles coupled to the cables to inconveniently dangle an excessive distance downwardly from the support arm(s). As a result, a need further exists for an exercise apparatus overcoming the shortcomings of prior art cable assemblies. 
     SUMMARY OF THE INVENTION 
     The present invention provides an exercise apparatus including a resistance assembly having a base and a weight stack assembly. Right and left extension arms each include a proximal end pivotally coupled to the resistance assembly, and a free distal end from which respective first and second ends of the cable extend. Upper and lower guide pulleys are attached to each end of the resistance assembly adjacent the proximal ends of the right and left extension arms. 
     The upper and lower guide pulleys are positioned such that when the extension arms are pivoted so that they are at a generally upward angle, the cable contacts at least the upper pulley. When the extension arms are pivoted so that they are at a generally downward angle, the cable contacts at least the lower pulley. In one embodiment of the invention, when the extension arms are pivoted so that they are at a generally downward angle, the cable contacts both the upper and lower pulleys. 
     The configuration of the upper and lower pulleys ensures that the cable is properly positioned with respect to the respective extension arm regardless of whether the extension arm is in an upper position or a lower position. This orientation of the pulleys allows the cable to move freely without binding, regardless of the orientation of the extension arms. This orientation also minimizes the shortening or lengthening of the portion of the cable extending from the distal ends of the extension arms when the arms are moved upwardly or downwardly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an exercise apparatus of the present invention; 
         FIG. 2  is a frontal view of the exercise apparatus of  FIG. 1  along the line  2 — 2  with the weight stack shown in partial cross section; 
         FIG. 3  is a cutaway side view of the first end of the extension arm of the exercise apparatus of  FIG. 1 ; 
         FIG. 4  is a perspective view of a pivoting pulley assembly of the exercise apparatus of  FIG. 1 ; 
         FIG. 5A  is a side view of the an alternative exercise apparatus in accordance with the present invention demonstrating the cable contacting an upper pulley; 
         FIG. 5B  is a side view of the exercise apparatus of  FIG. 5  showing the extension arm in a fully lowered position and demonstrating the cable contacting a lower pulley. 
         FIG. 6  is a front view of the exercise apparatus of  FIG. 5  with the resistance assembly shown in partial cross section; 
         FIG. 7  is a side cutaway view of the mounting bracket assembly of the exercise apparatus of  FIG. 5  (cable not shown). 
         FIG. 8  is side cutaway view of the mounting bracket of  FIG. 7  showing various offset distances (cable not shown). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1–3 , an exercise apparatus  10  is disclosed. The exercise apparatus  10  includes a resistance assembly  24  having (i) a base  16 ; and (ii) a weight stack assembly  24 A. Right and left extension arms  12 ,  14  each include a proximal end  60  pivotally coupled to the resistance assembly  24 , and a free distal end  62  from which respective first and second ends  46 ,  48  of a cable  28  linked to the resistance assembly  24  extend. 
     The resistance assembly includes a base structure  16  having a central user support member  18  with a free first end  20  and a second end  22  to which the weight stack assembly  24 A is secured. The central user support member  18  includes a platform  26  sized, shaped and constructed to support a standing user while he or she operates the exercise apparatus  10 . 
     A single cable  28  links the user handles  30  to the weight stack assembly  24 A. In one embodiment, the cable  28  is run through a series of pulleys to provide a 4:1load ratio for each handle  30 . In this way, a four hundred pound stack of weight plates  32  may be moved by the application of one hundred pounds force at each handle  30  (two hundred pounds total force when both handles are used simultaneously). 
     The 4:1 ratio reduces the inertia of the weight plates  32  by reducing the rate of movement of the weight plates  32  compared to the rate of travel at the handle  30 . Single hand movements allow the handle  30  to move four times faster than the weight plates  32  and dual hand movement allows the handles  30  to move twice the speed of the weight plates  32 . The 4:1 ratio also provides single hand movements equal in length to four times the travel distance of the weight plates  32 . This allows extended movements, such as, for example, overhead lift and bicep curls in addition to the dead lift movements, to provide users with greater flexibility in choosing a desired resistance level. 
     The series of pulleys over which cable  46  moves includes a first guide pulley  84  and a second guide pulley  85  located adjacent the proximal end of the right extension arm  12 . Corresponding guide pulleys  84 A,  85 A are located adjacent the proximal end of the left extension arm  14 . Guide pulleys  84 ,  84 A are upper pulleys, while guide pulleys  85 ,  85 A are lower pulleys. 
     As illustrated in  FIG. 1 , when the arm  12  is located in a first position the cable  28  contacts pulley  84 . When the arm  12  is lowered to a second position, the cable  28  contacts pulley  85  as well as pulley  84 . 
     Referring now to  FIG. 2 , the weight stack assembly  24 A includes a support frame  34  with vertical support members  36  aligned to support the stack of weight plates  32 . The weight plates  32  are supported for movement up and down in a conventional manner. The pulleys and cable  28  are used to lift weight plates  32 . The weight stack assembly  24 A includes a protective sleeve  38  positioned about the support frame  34  and the stack of weight plates  32 . 
     Cable  28  actuates the weight stack assembly  24 A and controls the movement of the weight plates  32 . The central portion  40  of cable  28  is passed over first and second central upper pulleys  42 ,  44 . 
     Opposing ends  46 ,  48  of cable  28  then extend downwardly within the weight stack assembly  24 A to respectively engage first and second movement pulleys  50 ,  52 . The movement pulleys  50 ,  52  are attached to a coupling member  54  attached to the stack of weight plates  32  (e.g., through the use of a perforated selector rod and an insertable locking pin). In this way, upward movement of the movement pulleys  50 ,  52  causes the coupling member  54  to move upwardly, and ultimately lift weight plates  32  against the force of gravity. 
     The first and second ends  46 ,  48  then extend upwardly and respectively pass over respective first and second exit pulleys  56 ,  58 . After passing over the exit pulleys  56 ,  58  and exiting the confines of the weight stack assembly  24 A, the ends  46 ,  48  extend downwardly until they contact the upper and lower guide pulleys  84 ,  84 A,  85 , and  85 A, then enter the respective right and left extension arms  12 ,  14 . Although a preferred orientation is disclosed for the various pulleys used in accordance with the present invention, those skilled in the art will readily understand that the exact orientation of the pulleys may be varied without departing from the spirit of the present invention. 
     The right and left extension arms  12 ,  14  are pivotally coupled to mounting brackets  65 ,  65   a , which are fixed to the weight stack assembly  24 A. Each extension arm  12 ,  14  pivots about a pivot axis and, in one embodiment, the pivot axes of the right and left extension arms  12 ,  14  are substantially aligned. 
     In the embodiments shown in  FIGS. 1–3 , the right and left extension arms  12 ,  14  are substantially identical and will now be described with reference to at least the right extension arm  12 . Referring to  FIGS. 1–3 , the right extension arm  12  includes a proximal end  60  and a distal end  62 . The proximal end  60  of the right extension arm  12  is pivotally coupled to a mounting bracket  65 , which is fixed to a first side  64  of the weight stack assembly  24 A. The proximal end  60  of the left extension arm  14  is pivotally coupled to mounting bracket  65   a  which is fixed to the opposite side  66  of the weight stack assembly  24 A. The left and right extension arms  12 ,  14  are pivotally coupled in a manner allowing a user to select a desired orientation for the arms relative to the weight stack assembly  24 A and to lock the arms  12 ,  14  in place. Movement of the right and left extension arms  12 ,  14  is assisted by the inclusion of a counterweight  68  at the proximal end  60  of the arms. 
     The right extension arm  12  includes a locking hole  70  ( FIG. 3 ). The locking hole  70  is located adjacent a pivot hole  72  through which a pivot pin  74  passes to pivotally couple the right extension arm  12  to the weight stack assembly  24 A. The locking hole  70  is aligned with a series of flange holes  76  formed on a semicircular flange  78  of the weight stack assembly  24 A. The semicircular flange  78  is positioned substantially parallel to the plane in which the right extension arm  12  pivots as it moves relative to the weight stack assembly  24 A. 
     In practice, and, as those skilled in the art will readily appreciate, a locking pin  80  is passed though an aligned locking hole  70  and flange hole  76  to lock the extension arm  12  at a desired angular orientation relative to the weight stack assembly  24 A. When a user desires to change the angular orientation of the right extension arm  12 , the locking pin  80  is simply removed and the locking hole  70  is aligned with another flange hole  76  at which time the locking pin  80  is once again inserted in position to lock the right extension arm  12  relative to the weight stack assembly  24 A. 
     First and second guide pulleys  84 ,  85  are fixed to the mounting bracket  65  near end  60  of the right extension arm  12 . Corresponding third and fourth guide pulleys  84 A,  85 A, operate in a similar fashion with respect to the left extension arm  14 . 
     Depending on the position of the extension arm  12 , the first end  46  of the cable  28  passes over at least one of the guide pulleys  84 ,  85  and possibly both guide pulleys  84 ,  85  before entering the tubular passageway formed in the right extension arm  12 . As shown in  FIGS. 1–3 , if the right extension arm  12  is positioned at an upward angle from the horizontal, the first end  46  of the cable  28  comes down from pulley  56  at the top of weight stack assembly  24 A, passes around the first guide pulley  84  and enters the tubular passageway in the right extension arm  12 . 
     On the other hand, if the right extension arm  12  is positioned at a downward angle, the first end  46  of the cable  28  comes down from pulley  56  at the top of weight stack assembly  24 A, passes around the first guide pulley  84  and then the second guide pulley  85 , and then enters the tubular passageway in the right extension arm  12 . This orientation of the first and second guide pulleys  84 ,  85 , (and guide pulleys  84 A,  85 A, which may be identically or similarly oriented for the left extension arm  14 ) allows the cable  28  to move freely within the tubular passageway without binding regardless of the orientation of the extension arms. This orientation further minimizes variations in the length and tension of the cable  28  as at least one of the extension arms is moved upwardly or downwardly. Thus, cable tension does not vary substantially as one or both extension arms  12 ,  14  are moved from an upper position to a lower position. 
     Upon reaching the distal end  62  of the right extension arm  12 , the first end  46  passes over the pivoting pulley assembly  82  and is ready for engagement by a user of the present apparatus. The distal end of the first end  46  of the cable  28  may be fitted with a wide variety of handles  30  known to those skilled in the art. 
     Referring briefly to  FIGS. 1 and 4 , the distal end  62  of the right extension arm  12  is fitted with a pivoting pulley assembly  82  which guides the first end  46  of the cable  28  as it exits the right extension arm  12 . The pivoting pulley assembly  82  is shown in greater detail in  FIG. 4 . Each pivoting pulley assembly  82  includes a frame  86  with a central pivot  88  for rotatably supporting a pulley member  90 . The frame  86  is formed so as to cover the pulley member  90  and thereby prevent undesired access with the pulley member  90  as the cable  28  passes thereover. The frame  86  is further provided with a counterweight  92  opposite the pulley member  90 . 
     The frame  86  further includes a cylindrical coupling member  94  shaped and dimensioned for pivotal attachment to the distal end  62  of the extension arms  12 ,  14 . The cylindrical coupling member  94  provides an opening through which the cable  28  passes as it extends from the extension arms  12 ,  14  toward the pulley member  90 . In this way, the cable  28  passes along the axis about which the pivoting pulley assembly  82  pivots relative to the extension arms  12 ,  14  to provide greater freedom of motion as an individual attempts to draw the cable  28  in various directions during exercise. 
     Since the pivoting pulley assembly  82  permits a great degree of flexibility with regard to the angle at which the cable  28  is drawn from the extension arms  12 ,  14  the inclusion of the present pivoting pulley assemblies  82  at the distal end of each extension arm  12 ,  14  greatly increases the flexibility of the present exercise apparatus. 
     The respective ends of the first and second ends  46 ,  48  are each provided with stop members  96 ,  98 . As those skilled in the art will readily appreciate, the stop members  96 ,  98  control motion of the single cable  28  to allow exercise by pulling the first end  46  alone, the second end  48  alone, or both ends at the same time. The guide pulleys  84 ,  85  are positioned such that the stop members remain substantially in contact with the pivoting pulley assembly  82  regardless of the position of the arm. The guide pulleys  84 ,  85  thus provide sufficient tension on the cable  28  to prevent the handles  30  coupled to the ends  46 ,  48  from dangling excessively from the extension arms  12 ,  14 , regardless of whether the arms  12 ,  14  are in an upward or a downward position. 
     In use, and after the right and left extension arms  12 ,  14  are properly positioned in a desired orientation, the user stands upon the central member  18 , grips the handles  30  secured to the ends of the respective ends and performs the desired lifting exercises. 
     With reference to  FIGS. 5–8 , another embodiment of the exercise apparatus  110  of the present invention is disclosed. Exercise apparatus  110  includes a pair of extension arms  112 ,  114  positioned to facilitate a wide range of lifting type exercises. The extension arms  112 ,  114  of the exercise apparatus  110  extend outwardly in different directions to provide the user with access to cable ends positioned for gripping when a user fully extends his or her arms outwardly in opposite directions. 
     The exercise apparatus  110  includes a resistance assembly  124  having (i) a base  116 ; and (ii) a weight stack assembly  124 A. Right and left extension arms  112 ,  114  each include a proximal end  160  pivotally coupled to the resistance assembly  124 , and a free distal end  162  from which respective first and second ends  146 ,  148  of a cable  128  linked to resistance assembly  124  extend. 
     A single cable  128  links the user handles  130  to the weight stack assembly  124 A. In one embodiment, the cable  128  is run through a series of pulleys to provide a 4:1 load ratio for each handle. In this way, a four hundred pound weight stack may be moved by the application of one hundred pounds force at each handle  130  of the device  110  (two hundred pounds total force when both handles are used simultaneously). 
     With reference to  FIG. 6 , the weight stack assembly  124 A secured to the central support member  118  includes support frame  134  having vertical support members  136  aligned to support a stack of weight plates  132 . The weight plates  132  are supported for movement up and down in a conventional manner. The weight stack assembly  124 A is covered by a protective sleeve  138  positioned thereabout. 
     When force is applied by the user, the cable  128  lifts the stack of weight plates  132 . The central portion  140  of the cable  128  is passed over first and second central upper pulleys  142 ,  144 . 
     First and second ends  146 ,  148  of the cable  128  then extend downwardly within the weight stack assembly  124 A to respectively engage first and second movement pulleys  150 ,  152 . The movement pulleys  150 ,  152  are attached to a coupling member  154  coupled to the stack of weight plates  132  (e.g. using a perforated selector rod and an insertable locking pin). In this way, upward movement of the movement pulleys  150 ,  152  causes the coupling member  154  to move upwardly, and ultimately lifts weight plates  132  upwardly against the force of gravity. 
     The first and second ends  146 ,  148  then extend upwardly and respectfully pass over respective first and second exit pulleys  156 ,  158 . After passing over the exit pulleys  156 ,  158 , and exiting the confines of the weight stack assembly  124 A, the ends  146 ,  148  extend downwardly until they contact upper and lower guide pulleys  184 ,  184 A,  185 ,  185 A and then enter respective right and left extension arms  112 ,  114  which are discussed below in greater detail. Although a preferred orientation is disclosed for the various pulleys used in accordance with the present invention, those skilled in the art will readily understand that the exact orientation of the pulleys may be varied without departing from the spirit of the present invention. 
     The right and left extension arms  112 ,  114  are pivotally coupled to mounting brackets  165 ,  165 A, which are fixed to a central portion of the weight stack assembly  124 A. The right and left extension arms  112 ,  114  respectively rotate about a first axis and a second axis, which are positioned to orient the right and left extension arms  112 ,  114  in an opposed relationship. The right and left extension arms  112 ,  114  extend outwardly from the central support member  118 . In this way, the ends of the extension arms  112 ,  114  are moved from the stack to improve user access to the present apparatus  110  while exercising. As those skilled in the art will readily appreciate, the exact angular orientation of the arms is not critical and may be varied slightly without departing from the spirit of present invention. 
     In the embodiment shown in  FIGS. 5–8 , the extension arms  112 ,  114  are substantially identical and will now be described with reference to at least the right extension arm  112 . The right extension arm  112  includes a proximal end  160  and distal end  162 . In accordance with the preferred embodiment of the present invention, the length of the right arm  112  is approximately  32  inches from pivot point  174  to the end  162 , although those skilled in the art will appreciate that the length of the right extension arm  112  may be varied slightly without departing from the spirit of the present invention. 
     The right extension arm  112  is pivotally coupled, at a position near the proximal end  160  of the extension arm  112 , to a mounting bracket  165 , which may be secured to either the side or the front of weight stack assembly  124 A. A semicircular flange assembly  178  is also secured to mounting bracket  165 . The semicircular flange assembly  178  includes a pair of opposed flat plates and is mounted to lie within the plane in which the right extension arm  112  rotates as it moves relative to the weight stack assembly  124 A. Movement of the right extension arm  112  is controlled by the inclusion of a counterweight  168  at the proximal end  160  of the right extension arm  112 . 
     The right extension arm  112  is pivotally coupled in a manner allowing a user to select a desired orientation for the extension arm  112  and lock the extension arm  112  in place. Specifically, the right extension arm  112  includes a locking hole  170  located adjacent a pivot hole  172  through which a pivot pin  174  passes to pivotally couple the right extension arm  112  to the mounting bracket  165 , and ultimately, the weight stack assembly  124 A. The locking hole  170  is aligned with a series of flange holes  176  formed in the semicircular flange assembly  178  of the mounting bracket  165 . 
     In practice, and as those skilled in the art will readily appreciate, a locking pin  180  is passed though an aligned locking hole  170  and flange hole  176  to lock the right extension arm  112  at a desired angular orientation relative to the weight stack assembly  124 A. When a user desires to change the angular orientation of the right extension arm  112 , the locking pin  180  is simply removed and the locking hole  170  is aligned with another flange hole  176  at which time the locking pin  180  is once again inserted in position to lock the right extension arm  112  relative to the weight stack assembly  124 A. 
     First and second guide pulleys  184 ,  185  are fixed to the mounting bracket  165  near the proximal end  160  of the right arm  112 . Corresponding third and fourth guide pulleys  184 A,  185 A, operate in a similar fashion with respect to the left extension arm  114 . Pulleys  184  and  184 A are upper pulleys, while pulleys  185  and  185 A are lower pulleys. 
     Depending on the position of the extension arm  112 , the first end  146  of the cable  128  passes over at least one of the guide pulleys  184 ,  185  (and possibly both guide pulleys) and then enters the tubular passageway formed in the right extension arm  112 . As shown in  FIG. 5A , if the right extension arm  112  is positioned at an upward angle from the horizontal, the first end  146  of the cable  128  comes down from pulley  156  at the top of weight stack assembly  124 A, passes around the first guide pulley  184  and enters the tubular passageway in the right extension arm  112 . As shown in  FIG. 5B , if the right extension arm  112  is positioned at a sufficient downward angle, the first end  146  of the cable  128  comes down from pulley  156  at the top of weight stack assembly  124 A, passes around both of the guide pulleys  184 ,  185 , and enters the tubular passageway in the right extension arm  112 . This orientation of the first and second guide pulleys  184 ,  185  allows the cable  128  to move freely within the tubular passageway without binding regardless of the orientation of the arms, and prevents substantial variations in tension as the arm  112  is moved upwardly or downwardly. 
     The distal end  162  of the right extension arm  112  is fitted with a pivoting pulley assembly  182  to guide the first end  146  of the cable  128  as it exits the right extension arm  112 . The pivoting pulley assembly  182  can be exactly the same as or substantially the same as that disclosed in  FIG. 4  and discussed above in substantial detail. Since the pivoting pulley assembly  182  permits a great degree of flexibility with regard to the angle at which the cable  128  is drawn from the right extension arm  112 , the inclusion of the present pivoting pulley assembly  182  at the distal end of each extension arm  112 ,  114  greatly increases the flexibility of the present exercise apparatus. 
     The respective ends of the first and second ends  146 ,  148  are each provided with stop members  196 ,  198 . As those skilled in the art will readily appreciate, the stop members  196 ,  198  control motion of the single cable to allow exercise by pulling the first end  146  alone, the second end  148  alone, or both ends at the same time. In use, and after the extension arms are properly positioned in a desired orientation, the user stands in front of the weight stack, grips the handles secured to the ends of the respective ends and performs desired lifting exercises. 
     With reference now to  FIG. 8 , an embodiment of the upper and lower pulleys of the present invention will now be discussed in additional detail. The pulleys  84 ,  84 A, and/or  85 ,  85 A described in  FIGS. 1–4  may have similar or identical dimensions and relationships to those described now with reference to  FIG. 8 . In addition, the pulleys  184 A,  185 A may have identical or similar dimensions and relationships to those described now with reference to  FIG. 8 . 
     Upper and lower pulleys  184 ,  185  have axes of rotation that are substantially parallel to and offset from the axis of rotation of the extension arm  112 . The axis of rotation of the upper pulley  184  is also offset from the axis of rotation of the extension arm  112  in the proximal direction a distance D 1 , and in the vertical direction a distance D 2 . The axis of the lower pulley  185  is also offset from the axis of rotation of the extension arm  112  in the proximal direction a distance D 4 , and in the vertical direction a distance D 3 . By orienting lower pulley  185  proximally with respect to upper pulley  184 , as shown in  FIGS. 8 and 5B , the cable is conveniently allowed to move along the distal portion of lower pulley  185  when arm  112  is in the lower position, providing space for the cable 
     In one preferred embodiment, distance D 1  is approximately ⅜ inch, distance D 2  is approximately 1¾ inches, distance D 3  is approximately 1 11/16 inches, and distance D 4  is approximately 1 3/16 inches. In one embodiment, in order to optimize the relationships between the pulleys  184 ,  185  and the axis of arm  112 , in addition to the distances discussed above, pulleys  184 ,  185  have a root diameter (the inside diameter portion actually contacted by the cable) of approximately 3 inches (e.g. 2 15/16 inches), and the cable has a diameter of about 3/16 inch. However, these distances are not intended to limit the invention, but rather to provide an example of an embodiment of the invention which minimizes variations in cable length and tension when the arms  112 ,  114  are moved. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.