Patent Publication Number: US-2019170203-A1

Title: Spring device

Description:
RELATED APPLICATION DATA 
     The present application claims benefit of co-pending provisional Ser. No. 62/056,992, filed Sep. 29, 2014, the entire disclosure of which is expressly incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to spring devices, and more particularly to holders for coupling to ends of a spring, and to methods for making and using such spring devices. 
     BACKGROUND 
       FIG. 1  depicts a typical extension (tension) spring  5  including spiral body coils  10 , hook  12 , and hook stress point  14 . Extension springs serve to apply a tension load to other machine elements, and to store energy. Extension springs generally fail (break) at the hook  12 , in particular at points of high stress such as hook stress point  14 . Hooks  12 , being relatively large, may also occupy valuable space inside of compact machinery. 
     Thus, an alternative way of connecting extension springs to other elements that avoids unnecessary stress points of the hooks and/or that is more compact than conventional hooks would be useful. 
     SUMMARY 
     The present invention is directed to spring devices and, more particularly, to holders for coupling to ends of a spring, and methods for making using such devices. 
     In accordance with an exemplary embodiment, a spring assembly is provided that includes a spring including a plurality of coils wound helically between first and second ends of the spring; and a spring disc attached to the first end of the spring between a first end coil terminating the first end and a second end coil adjacent the first end coil. 
     In accordance with another embodiment, a method is provided for making a spring assembly that includes providing a spring including a plurality of coils wound helically between first and second ends of the spring, a first end coil terminating the first end and a second end coil adjacent the first end coil; and attaching a spring disc to the first end of the spring between the first and second end coils. 
     Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It will be appreciated that the exemplary devices shown in the drawings are not necessarily drawn to scale, with emphasis instead being placed on illustrating the various aspects and features of the illustrated embodiments. 
         FIG. 1  is a perspective view of a conventional extension spring including hooks on its ends. 
         FIG. 2  is a perspective view of an exemplary embodiment of a hook-less extension spring. 
         FIG. 2A  is a perspective view of an alternative embodiment of a hook-less extension spring including variable pitch coils. 
         FIGS. 3A-3D  are various views of an exemplary embodiment of a spring disc. 
         FIG. 4A  is a side view of an exemplary embodiment of a spring assembly including the spring of  FIG. 2  and a pair of spring discs, such as those shown in  FIGS. 3A-3D , attached to ends of the spring. 
         FIG. 4B  is a cross-sectional view of the spring assembly of  FIG. 4A  taken along line  4 A- 4 A. 
         FIG. 4C  is an end view of the spring assembly of  FIG. 4A . 
         FIG. 5A  is a side view of the spring assembly of  FIG. 4A  with a connector element coupled to one of the spring discs. 
         FIG. 5B  is a cross-sectional view of the spring assembly of  FIG. 5A  taken along line  5 A- 5 A. 
         FIG. 5C  is a detail of one end of the spring assembly of  FIG. 5A . 
         FIG. 5D  is an end view of the spring assembly of  FIG. 5A . 
         FIGS. 6A and 6B  are perspective views of a spring assembly in unextended and extended positions, respectively. 
         FIG. 7  is a perspective view of an exemplary embodiment of an arm support system that may include a spring assembly, such as that shown in  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Turning to the drawings,  FIGS. 2-6B  show an exemplary embodiment of a spring assembly  100  that includes a hook-less extension spring  20  and a pair of spring discs  30  coupled to respective ends of the spring  20 . 
       FIG. 2  shows an exemplary embodiment of a hook-less extension spring  20  including a plurality of spiral body coils  22  formed from wire  26  having two coil ends  24 . Each coil end  24  includes a first end coil  27  at the very end terminating at the end of the wire  26  and a second end coil  28  adjacent the first end coil  27 . In a relaxed or lowest energy state, adjacent coils may abut one another, e.g., to provide a closed spring in its low energy state, yet may be resiliently separated, e.g., by extending the ends  24  away from one another. Alternatively, as shown in  FIG. 2A , the first and second end coils  27 ,′  28 ′ may be spaced apart from one another in a relaxed state to define a predefined gap  29 ,′ while the remaining coils  22 ′ may abut one another, which may facilitate installation of the spring disc (not shown) between the first and second end coils  27 ,′  28 .′ In exemplary embodiments, the spring  20  may be formed from a variety of materials, e.g., metal, plastic, and the like, having desired elasticity and/or other mechanical properties. 
     Turning to  FIGS. 3A-3D , an exemplary embodiment of a spring disc  30  is shown that includes attachment feature  44 , optional boss  46 , optional rim  48 , notch  54 , low surface  42 , high surface  40 , low notch end  56 , and high notch end  58 . Attachment feature  44  may be a hole, threaded hole, tab, hook, or other securing feature, e.g., for coupling the end of the spring assembly  100  to a cable or other element, e.g., along central axis  31 . 
     The spring disc  30  generally includes an at least partial annular disc with the low surface  42  offset around the circumference of the disc from the high surface  40  such that the notch  54  separates the high and low surfaces  40 ,  42 , as shown in  FIG. 3B . As can be seen in  FIGS. 3A and 3C , the disc  30  has a spiral or helical shape such that the disc  30  extends out of an imaginary plane perpendicular to the central axis  31 . In this manner, the low surface  42  may be offset along the central axis  31  relative to the high surface sufficiently to facilitate the joining of the spring disc  30  to the hook-less spring  20 , as described below. For example, the low surface  42  may be lower than the high surface  40  by approximately the diameter of the wire  26  in the hook-less spring  20 , e.g., between about 3-4 mm. In addition, the disc  30  may have a substantially uniform pitch or slope between the high surface  40  and the low surface  42 , e.g., corresponding to the pitch of the end coils of the spring  20 .  FIG. 3D  presents a cross-sectional view of the spring disc  30 , taken along line A-A of  FIG. 3B , showing the high surface  40  in relation to the low surface  42 . 
     Turning to  FIGS. 4A-4C , an exemplary embodiment of a spring assembly  100  is shown that includes a pair of spring discs  30 , such as that shown in  FIGS. 3A-3D , coupled to a hook-less spring  20 , such as that shown in  FIG. 2 . As shown, a spring disc  30  may be inserted into each end of the hook-less spring  20 , e.g., in between first end coil  27  and second end coil  28  at the very end of the spring  20 . The notch  54  in the spring disc  30  provides a passageway for the first end coil  27  (above the spring disc  30 ) to transition into the second end coil  28  (below the spring disc  30 ). The spring disc  30  may spread the end coils  27  and  28 , resulting in a gap  64 , as shown in  FIG. 4A . Alternatively, gap  64  may be formed into the hook-less spring  20  at the time of manufacture, for example, by forming the hook-less spring  20  with a space between the first end coil  27  and the second end coil  28 . 
     Optionally, a rim  48  may be provided around the outer perimeter of the spring disc  30 , e.g., extending upwardly from the top surface, which may keep the spring disc  30  substantially concentric with the hook-less spring  20  and the central axis  31 , e.g., by preventing the spring disc  30  from moving away from the center of the hook-less spring  20 . The rim  48  may be formed after the spring disc  30  is joined to the hook-less spring  20 , for example, by crimping or upsetting a portion of the spring disc  30 , or the rim  48  may be preformed in the spring disc  30 . As best seen in  FIG. 3B , the rim  48  may extend substantially continuously around the perimeter of the spring disc  30  between the low notch end  56  and the high notch end  58 , although alternatively, the rim  48  may be intermittent, e.g., defined by a plurality of tabs (not shown) spaced apart from one another around the perimeter of the spring disc  30 . 
     In addition or alternatively, an optional boss  46  may be provided, e.g., around the hole  44 , which may also maintain the spring disc  30  substantially concentric with the hook-less spring  20 . The spring disc  30  may be formed using a variety of materials, e.g., metal or plastic, and/or methods, e.g., stamping, machining, molding, and the like. For example, the nonplanar shape and/or features of the spring disc  30  may be formed when the spring disc is molded, machined or otherwise formed, or the spring disc  30  may be formed from a planar base and then the nonplanar shape may be formed into the base. 
       FIG. 4B  is a cross-sectional view of the spring assembly  100  taken along line A-A in  FIG. 4A , and shows the first end coil  27  lying substantially in contact with the high surface  40  and the low surface  42  of the spring disc  30 , which together approximate the spiral shape of the first end coil  27 . Again, optional rim  48  and/or boss  46  may act to keep the spring disc  30  substantially concentric with the hook-less spring  20 . 
       FIGS. 5A and 5B  show the spring assembly  100  with the tip  24  of the first end coil  27  (best seen in  FIG. 2 ) deformed to provide an optional tab end  130 , which may interfere with high notch end  58 , preventing the spring disc  30  from rotating out of the hook-less spring  20  (e.g., preventing it from “unscrewing” itself out of the hook-less spring  20 ). Alternatively, a notch or other feature (not shown) may be created in the first end coil  27  to prevent movement of the spring disc  30  once installed.  FIG. 5C  provides a magnified view of the optional tab end  130  interfering with the high notch end  58 . 
     Other features that interfere with, or attach to, a portion of the spring disc  30  to keep it from rotating out of the hook-less spring  20  may also be provided. For example, the coil end  24  may be bent sideways or downwards, or the first end coil  27  may be fastened to the spring disc  30  with a fastener, e.g., a clip, wire, or screw (not shown), and/or may be bonded with adhesives, or may be welded, soldered, and/or fused to the spring disc  30 . The spring disc  30  may also be fixed to other machine elements in a way that prevents the spring disc  30  from rotating, thus preventing it from rotating out of the hook-less spring  20 . 
     Optional fastening element  140  may extend from one or both spring discs  30  (only one shown in  FIGS. 5A and 5B  for simplicity), which may be a fastener, cable, or other suitable attachment element. The fastening element  140  may include an elongate shaft  142  terminating in an enlarged portion  144 , which may interfere with (or otherwise connect to) the hole or attachment feature  44 , and allow the fastening element  140  to apply tensile loads to the spring disc  30  (which, in turn, may apply a tensile load to the first end coil  27 , and thus the entire hook-less spring  20 ). For example, the fastening element  140  may include a cable, pin, or other elongate member  142  with an enlarged integral head  144 . Alternatively, instead of an integral head  144 , a separate nut or other element (not shown) that may be threaded onto the end of the elongate member  142 . In an exemplary embodiment, an elongate member may be coupled to each end of the spring to couple the spring to other components of a mechanical device, such as an arm support system, such as that shown in  FIG. 7  and/or as disclosed in U.S. Publication Nos. 1012/0184880 and 2014/0158839, the entire disclosures of which are expressly incorporated by reference herein. 
     The free end of the shaft  142  may be coupled to a cable or other machine element (not shown), e.g., using cooperating connectors, fasteners, threads, welding, soldering, and the like (also not shown). Alternatively, an end of a cable or other machine element may be coupled directly to the spring disc  30 , e.g., through the hole or other attachment feature  44 . 
       FIG. 6A  shows the spring assembly  100  with a spring disc  30  and fastening element  140  installed at each end, and the spring  20  in a relaxed (unloaded) or other low energy state.  FIG. 6B  shows the spring assembly  100  extended under tensile axial force Ft, which acts on the spring disc  30  through the fastening element  140 . The spring disc  30  in turn acts to apply an axial load to the first end coil  27 , which in turn transmits the load to the rest of the coils  22 . 
     Using the spring disc  30 , a cable or other fastening element may be coupled directly to the ends of the spring  20  thereby minimizing wasted space adjacent the spring  20 . In addition, the spring disc  30  may distribute forces on the ends of the spring  20  onto the perimeter of the first end coil  27 , thereby reducing the risk of spring failure as may occur with conventional spring hook ends (as shown in  FIG. 1 ). 
     Turning to  FIG. 7 , an exemplary embodiment of an arm support system  210  is shown that includes one or more spring assemblies, which may be similar to those described elsewhere herein. Generally, the system  210  includes a torso mounted harness  220 , and one or more adaptive arm supports  230  (only one shown) coupled to the harness  220 . The adaptive arm support  220  may be biased with a resilient element (e.g., including a spring assembly similar to those described elsewhere herein) and/or other components, to impart a desired force to the arm of a user (not shown), for example, to bear all, or part of, the weight of the arm. The force may vary with arm position or be substantially constant through its range of motion. 
     In the embodiment shown in  FIG. 7 , the arm support  230  includes a first arm support segment  232  pivotally coupled to the harness  220  about a first vertical axis such that the first arm support segment  232  is rotatable substantially horizontally about the first vertical axis relative to the harness  220 , and a second arm support segment  234  pivotally coupled to the first arm support segment  232  such that the second arm support segment  234  is rotatable about a second axis generally orthogonal to the first vertical axis. Optionally, the second arm support segment  234  may carry an arm rest  236  and/or other component for receiving the user&#39;s arm. 
     In addition, the arm support  230  includes one or more compensation elements  240 , e.g., including a pulley arrangement  242  mounted on the second arm support segment  234  and a cable  244  wrapped partially around the pulley  242  and including a first end coupled to a resilient member  246 , e.g., a spring assembly similar to those described elsewhere herein, and a second coupled to the first arm support segment  232  such that at least a portion of a force from the resilient member is applied to the second arm support segment  232  to the generate the offset force. 
     While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.