Abstract:
A torsion spring includes a spring body wound by a helical wire, a first arm extending tangently from an end of the spring body, and a second arm extending from the other end of the spring body. The first arm includes sequentially a first portion extending from the spring body, a curved second portion bent toward a first direction from the first portion, and a curved third portion bent toward a different second direction from the second portion. A torsion spring assembly and a releasable casing using the torsion spring are also disclosed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to spring configurations and, more particularly, to a torsion spring configuration and a releasable casing using the same. 
       DESCRIPTION OF RELATED ART 
       [0002]    A torsion spring is a mechanical element that reacts against torsion (twisting motion). A torsion spring is often made from a wire, ribbon, bar, or coil. Torsion Springs are widely used in automobiles, motorcycles, electrical appliances, telecommunication equipment, and other civil fields. 
         [0003]    In operation, the more the torsion spring is twisted, the more force it needs to twist the torsion spring further. That is, the torsion spring is a kind of non-constant force provider. 
         [0004]    Accordingly, to perform as a superior force provider, a need exists for a torsion spring configuration without the above disadvantages in the industry. 
       SUMMARY OF THE INVENTION 
       [0005]    A releasable casing includes a base, a lid coupled to the base, a first torsion spring and a second torsion spring. The lid is rotatable around a rotating axis with respect to the base. The first torsion spring includes a first spring body, a first arm, and a second arm extending from the spring body. The first arm resists the lid toward an opening direction of the lid, and the second arm is fixed relative to the base. The first arm includes a first portion connected to the first spring body, an arc-shaped second portion extending from the first portion, and an arc-shaped third portion extending from the second portion. The first portion extends from the first spring body along a tangent direction thereof, and the second portion and the third portion bend oppositely. The second torsion spring includes a second spring body, and a third arm and a fourth arm extending from the second spring body. The third arm resists against the lid, and the fourth arm is fixed relative to the base. 
         [0006]    A torsion spring assembly, which is used for opening a lid, includes a first spring and a second torsion spring. The first torsion spring includes a first spring body, a first spring arm configured for resisting against the lid, and a second spring arm configured for being fixed relative to the first spring body. The first and second spring arms extend from opposite ends of the first spring body. The first arm sequentially includes a first portion, a curved second portion, and a curved third portion. The third portion is deformable with respect to the first portion to apply a first force to prevent the lid from releasing. The second spring includes a second spring body, a third spring arm for resisting against the lid to apply a second force to release the lid, and a fourth spring arm for being fixed, the third and fourth spring arms extending from opposite ends of the second spring body. 
         [0007]    A torsion spring includes a spring body wound by a helical wire, a first arm extending tangently from an end of the spring body, and a second arm extending from the other end of the spring body. The first arm includes sequentially a first portion extending from the spring body, a curved second portion bent toward a first direction from the first portion, and a curved third portion bent toward a different second direction from the second portion. 
         [0008]    Other systems, methods, features, and advantages of the present torsion spring configuration and the present releasable casing with the torsion spring configuration will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present apparatus, and be protected by the accompanying claims. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present torsion spring configuration and the present releasable casing with the torsion spring configuration can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0010]      FIG. 1  is an isometric view of a releasable casing with a torsion spring configuration in accordance with an exemplary embodiment mounted thereto, the releasable casing including a lid, a base, a first torsion spring, and a second torsion spring; 
           [0011]      FIG. 2  is an exploded view of the releasable casing of FIG. I; 
           [0012]      FIG. 3  is an isometric view of the lid of  FIG. 1 , but viewed from an inverted aspect; 
           [0013]      FIG. 4  is a schematic view showing a relationship of the first torsion spring and the lid in a closed state; 
           [0014]      FIG. 5  is a schematic view showing a relationship of the first torsion spring and the lid in an intermediate state; and 
           [0015]      FIG. 6  is a schematic view showing a relationship of the first torsion spring and the lid in an opened state. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Reference will now be made to the drawings to describe in detail, the preferred embodiments of the present torsion spring configuration and the present releasable casing with the torsion spring configuration. 
         [0017]    Torsion springs are helical springs used to apply torque or store rotational energy. Torque by definition is a force that produces rotation. A torsion spring exerts a force of torque in a circular arc, and arms of the torsion spring rotate about a central axis thereof. 
         [0018]    A typical torsion spring includes a cylindrical body constructed with a helical wire, two ends of the helical wire form a pair of arms extending from the body. In use, the body is typically sleeved on a rod, either one of the pair of arms is fixed, while the other arm (a free arm) is movable relative to the rod. 
         [0019]    When a force is acted on the free arm at a distance from an axis of the torsion spring, the torque (a.k.a. moment), which is equal to the force multiplied by the arm of force (i.e. a distance of a point of contact of the arm), causes the free arm to rotate around the axis, thus, kinetic energy is transformed to potential energy. 
         [0020]    When the torsion spring releases/exerts the potential energy stored, the free arm of the torsion spring rotates and returns to an initial position. A force acted from the free arm of the torsion spring gradually decreases as the free arm moves closer to the initial position. Supposing that the above torsion spring is utilized to release a lid of a releasable casing, a force applied to the lid by the torsion spring would gradually decreases. This results in that the lid rotates unevenly together with the free arm of the torsion spring during the releasing process. 
         [0021]    As described above, it is difficult to choose an appropriate torsion spring for a given releasable casing. This is because in the given releasable casing, if the torsion spring thereof carries a relatively great torque, the lid would open and strike the releasable casing fiercely, resulting in undesired ricochets, shakes, or vibrations. Thus, the lid, or the releasable casing would be prone to damage. On the other hand, if the torsion spring carries a relatively small torque, the lid cannot open at a greatest releasing angle. 
         [0022]    Hereinafter, a torsion spring configuration is described in detail to solve the above problem satisfactorily. 
         [0023]    Referring to  FIG. 1  and  FIG. 2 , a releasable casing  100  with a lid  10  thereof released is illustrated. The releasable casing  100  includes a lid  10  and a base  20  pivotably attached together, further, a first torsion spring  30  and a second torsion spring  40  are used as force providers to provide a releasing force cooperatively, thus releasing the lid  10 . The lid  10  is rotatable around a rotating axis OO with respect to the base  20 , the position of the lid  10  with respect to the base  20  defines an opened state, a closed state, and a half opened state. The opened state is where the lid  10  is fully released from the base  20  at a largest opening angle, the closed state is where the lid  10  fully covers on the base  20 , and the half opened state is an intermediate state between the opened state and the closed state. The first torsion spring  30  and the second torsion spring  40  are utilized to provide the torque force that actuates the lid  10 . 
         [0024]    The lid  10  includes a first supporting portion  12  and a second supporting portion  14 , both of which are in quadrant shapes. The first and second supporting portions  12  and  14  are formed near an edge of the lid  10  with axes thereof superposing each other and the rotating axis OO of the lid  10 . A positioning slot  16  perpendicular to the rotating axis OO of the lid  10  is defined beside the second supporting portion  14 . The first supporting portion  12  and the positioning slot  16  are respectively used to position the first torsion spring  30  and the second torsion spring  40 . The second supporting portion  14  forms a partial gear  142  to engage/mesh with a gear (not shown) positioned in the base  20  thus, slowing down the lid  10  during an opening procedure and dampening an impact between the lid  10  and the base  20  when reaching the largest opening angle. 
         [0025]    The base  20  defines a first opening  22 , a second opening  24 , and a third opening  26 . The first opening  22  is defined near an edge of the base  20  corresponding to the first supporting portion  12  of the lid  10  allowing the first supporting portion  12  to extend therethrough. Similarly, the second opening  24  is defined near the edge of the base  20  corresponding to the second supporting portion  14  of the lid  10  allowing the second supporting portion  14  to extend therethrough. The third opening  26  is defined near the second opening  24  to allow an arm of the second torsion spring  40  to extend therethrough reaching the positioning slot  16  of the lid  10 . 
         [0026]    The first torsion spring  30  includes a first body  32  spun in a coil, and a first arm  34  and a second arm  36  extending from the first body  32 . The first arm  34  extends from an end of the first body  32  forming an S-shape, and the second arm  36  extends tangently from an opposite end of the first body  32 . The second arm  36  is relatively a straight arm extending from the first body  32 , and the first arm  34  includes a first portion  342  extending relatively straight along an opposite direction to the second arm  36 , an arc-shaped second portion  344 , and an arc-shaped third portion  346 . The second portion  344  and the third portion  346  are end-to-end, and the bending directions thereof are opposite to each other. That is, a center point of an imaginary circle conformed to the second portion  344  and a center point of an imaginary circle conformed to the third portion  346  are respectively positioned at two opposite sides of the first arm  34 . 
         [0027]    The second torsion spring  40  includes a second body  42  converted in coils, and a third arm  44  and a fourth arm  46  extending from the second body  42 . The third arm  44  and the fourth arm  46  are straight arms. The third arm  44  extends tangently from an end of the second body  42 , and the fourth arm  46  extends radially from another opposite end of the second body  42 . 
         [0028]    The first body  32  and the second body  42  are sleeved on rods (not shown) formed in the base  20  correspondingly. The first arm  34  of the first torsion spring  30  and the third arm  44  of the second torsion spring  40  are fixed to the lid  10  of the releasable casing  100 , while the second arm  36  of the first torsion spring  30  and the fourth arm  46  of the second torsion spring  40  are fixed to the base  20 . Detailedly, the first arm  34  resists against the first supporting portion  12  of the lid  10 , and the third arm  44  is restricted in the positioning slot  16  defined on the lid  10 . 
         [0029]    Referring to  FIG. 3  together, the first supporting portion  12  defines a sliding channel  120  at a bottom thereof to allow the first arm  34  to be restricted therein and slide therealong. 
         [0030]    Different states during an opening procedure of the lid  10  are respectively shown in  FIG. 4  to  FIG. 6 . 
         [0031]    Firstly referring to  FIG. 4 , a schematic view showing a relationship between the first torsion spring  30  and the lid  10  in the closed state is illustrated. In such a situation, the lid  10  fully covers the base  20 , and the first torsion spring  30  and the second torsion spring  40  are compressed. The first torsion spring  30  and the second torsion spring  40  carry great potential energy. The first portion  342  of the first torsion spring  30  is partially received in the sliding channel  120 , and the second portion  344  and the third portion  346  resist against the cambered surface  122  of the first supporting portion  12 . A contacting point X of the first arm  34  and the cambered surface  122  is on a conjunction of the second portion  344  and the third portion  346 . As a relative position of the third portion  346  and the first portion  342  is changed due to the first supporting portion  12  therebetween, the third portion  346  of the first arm  34  applies a restoration force through the contacting point X onto the first supporting portion  12  along a radial direction of the first supporting portion  12 . The restoration force holds the first supporting portion  12  onto the base  20 . 
         [0032]    Subsequently referring to  FIG. 5 , a schematic view showing a relationship between the first torsion spring  30  and the lid  10  in the half opened state is illustrated. As the lid  10  rotates relative to the rotating axis OO, a contacting point Y of the first arm  34  and the cambered surface  122  of the first supporting portion  12  gradually moves along the cambered surface  122 . The restoration force applied by the third portion  346  of the first arm  34  holding the first supporting portion  12  of the lid gradually decreases. 
         [0033]    Finally referring to  FIG. 6 , a schematic view showing a relationship between the first torsion spring  30  and the lid  10  in the opened state is illustrated. As the lid  10  rotates around the rotating axis OO to reach the largest opening angle, a contacting point Z of the first arm  34  of the first torsion spring  30  and the first supporting portion  12  gradually moves into the sliding channel  120 . In such a situation, the third portion  346  of the first arm  34  applies a supporting force to the first supporting portion  12  to support the lid  10  at the largest opening angle. 
         [0034]    As described above, from the closed state to the half opened state, the first torsion spring  30  applies a first force onto the first supporting portion  12  holding the first supporting portion  12  in the opening procedure. Meanwhile, the second torsion spring  40  applies a second force onto the lid  10  releasing the lid  10 . During such a procedure, the first torsion spring  30  holds the lid  10 , and the second torsion spring  40  releases the lid, thus, a resultant force of the first force and a second force applied to the lid  10  releasing the lid  10  is adjusted. As the opening angle increases, the first force applied by the first torsion spring  30  decreases, and the second force applied by the second torsion spring  40  decreases. Therefore, the resultant force of the first force and the second force changes slightly or remains constant. From the half opened state to the opened state, the third portion  346  of the first arm  34  moves into the sliding channel  120 . The first force applied by the first torsion spring  30  disappears, and a third force is generated by the first arm  34  supporting the lid  10 , helping the lid  10  to reach and remain at the largest opening angle. The second force applied by the second torsion spring  40  decreases continuously. When the third portion  346  moves into the sliding channel  120 , the second force and the third force applied respectively by the first torsion spring  30  and the second torsion spring  40  together support the lid  10 , and keep the lid  10  at the largest opening angle. 
         [0035]    A closing procedure is a reverse procedure of the above opening procedure. 
         [0036]    It is clear that the first torsion spring  30  cooperates with the second torsion spring  40  to maintain the releasing force of lid  10  during the releasing procedure, and to support the lid  10  at the largest opening angle so as to eliminate/depress shakes of the lid  10  in the opened state. Such a configuration of the first torsion spring  30  and the second torsion spring  40  effectively resolves common problems of conventional torsion springs. The releasable casing  100  is superior to those by having a substantially constant releasing force on the lid  10  and a long work life thereof due to depressed/eliminated strikes. This torsion spring configuration can be utilized in many electronic devices, such as a game player, a disc player, a tool box, or even a dressing case, etc. 
         [0037]    It should be emphasized that the above-described embodiments of the present invention, including any preferred embodiments, are merely possible examples of implementation of the principles of the invention, and are merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and be protected by the following claims.