Abstract:
A slide joint that is fit over a first member and joints a second member to the first member includes a cylinder defining a bore having an axis and having a surface defining a groove and a ring including a flat body defining another bore having another axis and a sidewall extending from the body and fit over the cylinder with the bores partly overlapping each other to allow the first member to extend therethrough, the axes being eccentric with respect to each other. The ring is rotatable about the cylinder between a first position where the axes have a first eccentricity and a second position where the axes have a second eccentricity that is smaller than the first eccentricity whereby the bores tightly engage the first member to secure the slide joint on the first member.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a slide joint that is movable along an elongate member, and in particular to a slide joint comprising an eccentric locking mechanism that selectively locks the slide joint at any position along the elongate member.  
         [0003]     2. The Related Art  
         [0004]     A slide joint is commonly employed to joint a first member to a second, elongate member of a collapsible or configuration-adjustable device, such as a foldable deck chair or an adjustable sun-shade device, whereby the first member is allowed to selectively move along the second member to realize collapse/expansion and adjustability of the device comprised of the joint. Some conventional designs only allow the slide joint to be moved between and secured at two opposite ends of the elongate member. This limits the applicability of the slide joint. Some other conventional designs employ complicated mechanisms to selectively secure the slide joint at predetermined locations along the elongate member, which suffers high costs and complicated and thus inconvenient operation.  
         [0005]     Thus the present invention is aimed to provide a slide joint that overcomes the drawbacks of the prior art.  
       SUMMARY OF THE INVENTION  
       [0006]     A primary objective of the present invention is to provide a slide joint that is movable along an elongate member and is selectively secured at any position along the elongate member by a locking mechanism having a simple structure.  
         [0007]     Another objective of the present invention is to provide a slide joint for moving along an elongate member, comprising a locking mechanism featuring a sliding cylinder and a rotating ring that are eccentric with respect to each other for selectively securing the slide joint on the elongate member by relative rotation therebetween.  
         [0008]     A further objective of the present invention is to provide a slide joint that axially movably joint a first member to an elongate second member while allowing rotation of the first member with respect to the second member about an axis substantially normal to the second member.  
         [0009]     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a slide joint constructed in accordance with the present invention;  
         [0011]      FIG. 2  is an exploded view of the slide joint of the present invention;  
         [0012]      FIG. 3  is a perspective view showing the slide joint couples two members together;  
         [0013]      FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 3 ;  
         [0014]      FIG. 5  is a plan view showing the slide joint in a non-locked condition;  
         [0015]      FIG. 6  is similar to  FIG. 5  but showing the slide joint in a locked condition;  
         [0016]      FIG. 7  is a perspective view showing a rocking chair in which a seat is coupled to a rocker by the slide joint of the present invention;  
         [0017]      FIG. 8  is a perspective view showing a sun shade device comprising a canopy movably coupled to an upright stem by the slide joint of the present invention; and  
         [0018]      FIG. 9  is an exploded view showing a slide joint constructed in accordance with another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Referring to the drawings and in particular  FIGS. 1 and 2 , as well as  FIG. 4 , a slide joint constructed in accordance with the present invention, generally designated with reference numeral  10 , comprises a cylinder  12  and a locking ring  14  rotatable with respect to each other. The cylinder  12  defines a central bore  16  extending along a first central axis A (see  FIG. 4 ). The cylinder  12  has an outside surface (not labeled) forming a circumferential shoulder or flange  18 , dividing the outside surface of the cylinder into a first, enlarged section  20  and a second, reduced section  22 . A circumferential groove  24  is defined in the reduced section  22  and is axially spaced from the shoulder  18 . The expanded section  20  forms a radial projection  26  forming a planar surface  28  in which an inner-threaded hole  30  is defined.  
         [0020]     A U-shaped coupling member  32 , comprising two spaced, opposite lugs  34  connected by a bottom  36 . The bottom  36  is substantially flat and positioned against the planer surface  28  of the radial projection  26  in a surface contact manner. Preferably, the flat bottom  36  has a size and shape corresponding to the planer surface  28  of the radial projection  26  of the cylinder  12 . A through hole  38  is defin in the flat bottom  36  for the extension of a pivot pin  40 . The pivot pin  40  has an external thread (not labeled) that engages the inner-threaded hole  30  of the radial projection  26 , while allowing rotation of the coupling member  32  about the pin  40  itself, thereby rotatably attaching the coupling member  32  to the cylinder  12 .  
         [0021]     Preferably, the inner-threaded hole  30  and the through holes  38 , and thus the pivot pin  40  received therein, extend along an axis D that is substantially perpendicular to the central axis A of the cylinder  12 . However, it is not necessary to be so. The axis D can be inclined with respect to the axis A at any desired angle.  
         [0022]     The rotating ring  14  comprising a flat ring body  42  and a cylindrical side wall  44  extending from an outer circumference of the ring body  42  and rotatably fit over the reduced section  22  of the cylinder  12 . The cylindrical side wall  44  of the ring  14  has an inner diameter that is substantially corresponding to an outside diameter of the reduced section  22  of the cylinder  12  whereby the cylindrical side wall  44  is snugly fit over the reduced section  22  and is guided, in rotation, by the reduced section  22  of the cylinder  12 .  
         [0023]     At least one inward projection is formed on an inside surface of the side wall  44  of the rotating ring  14  and movably received in the groove  24  of the cylinder  12  for guiding the rotation of the rotating ring  14  about the reduced section  22  of the cylinder  12 . In the embodiment illustrated, the projection is comprised of a bolt  46  that threadingly engages an inner-threaded hole  48  defined through the side wall  44  with a tip of the bolt  46  extending through the side wall  44  and partially received in the groove  22 . The receipt of the tip of the bolt  46  in the groove  24  functions to guide the rotation of the rotating ring  14  about the reduced section  22  and prevent the rotating ring  14  from sliding off the reduced section  22 .  
         [0024]     Preferably, three such guide projections  46  are provided on the side wall  44  and equally spaced along a circumference of the side wall  44 .  
         [0025]     The ring body  42  forms a through hole or bore  50 , preferably of the same size as the central bore  16  of the cylinder  12 , defining a central axis B that is offset from the axis A, see  FIG. 4 . The rotation of the rotating ring  14  about the reduced section  22  of the cylinder  12  moves the through hole  50  between a locking position where the offset between the axes A and B is of a large amount ( FIG. 6 ) and a non-locking position where the offset between the axes A and B is of a small amount ( FIG. 5 ). A manual handle  52  projects from the side wall  44  of the rotating ring  14  in a radial direction to facilitate manual rotation of the rotating ring  14  about the reduced section  22  of the cylinder  12 .  
         [0026]     A bolt  54  engages an inner-threaded hole  56  defined in the ring body  42  and is of a size that allows a tip of the bolt  54  to extend beyond the ring body  42  and selectively engaging a dimple  58  defined in a top surface  60  of the reduced section  22  of the cylinder  12  to secure the rotating ring  14  in the locking condition. Preferably, the bolt  54  is a wing-headed bolt to facilitate manual rotation thereof.  
         [0027]     Also referring to  FIGS. 3-6 , to joint two members together, the slide joint  10  is fit over a first, elongate member  62  having a cross-sectional area smaller than the bore  16  of the cylinder  12  and the through hole  50  of the rotating ring  14 . Thus, the first member  62  loosely extends through both the cylinder  12  and the ring  14 . Preferably, the relative angular position between the ring  14  and the cylinder  12  is such that small friction is induced between the bore  16  of the cylinder  12  and the first member  62 , and between the through hole  50  of the ring  14  and the first member  62 , as illustrated in  FIG. 5 , which is the non-locking condition of the slide joint  10 . This allows the slide joint  10  to be temporarily positioned along the first member  62 .  
         [0028]     By rotating the ring  14  with the aid of the manual handle  52  with respect to the cylinder  12  as indicated by arrow E of  FIG. 5 , the ring  14  is moved to the locking condition where the offset between the axes A and B of the through hole  50  and the bore  16  is largest, making the through hole  50  and the bore  16  tightly engaging the first member  62  thereby securing the slide joint  10  on the first member  62 , as illustrated in  FIG. 6 . The bolt  54  may then be secured in the dimple  58  to fix the ring  14  with respect to the cylinder  12  and prevents the slide joint  10  from getting loosened.  
         [0029]     Referring back to  FIGS. 2 and 3 , a block  44  is formed on the shoulder  18  of the cylinder  12  and is movably received in a slot  66  defined partially along an inner circumference of the side wall  44 . The slot  66  has opposite ends that are brought into engagement with the block  44  when the ring  14  is rotated to the locking condition and non-locking condition, respectively. Thus, the block  64  serves as a stop that limits the rotation of the ring  14  in the directions toward both locking and non-locking conditions.  
         [0030]     The lugs  34  of the coupling member  32  defines a space therebetween for receiving a second member  68  that is to be movably jointed to the first member  62  by the slide joint  10  of the present invention. The second member  68  can be fixed in the space between the lugs  34  by any known means, such as a pivot  70  ( FIG. 3 ) extending through aligned holes  72  defined in the lugs  34  and a corresponding hole (not shown) defined through the second member  68 . This allows the second member  68  to be rotatable with respect to the slide joint  10  about both the axis D and an axis defined by the pivot  70 , which can be perpendicular to the axis D.  
         [0031]      FIG. 7  shows a rocking chair, generally designated with reference numeral  100 , comprises a seat portion  102  and two spaced rockers  104  on opposite sides of the seat portion  102 . Each rocker  104  comprises a curved, concave bottom bar  106  and an arch-like, convex top bar  108 . A stretch bar  110  extends between the top bar  108  and the bottom bar  106 . A slide joint  10  of the present invention is fit over the stretch bar  110 . In other words, the stretch bar  110  functions as the first member  62  discussed with reference to  FIGS. 3 and 4 .  
         [0032]     The seat portion  102  comprises a seat base  112  and a backrest  114  pivotally jointed together. Opposite edges of the seat base  112  are attached to the coupling members  32  of the slide joints  10  and opposite edges of the backrest  114  are pivoted to the top bars  108  of the rockers  104 . By sliding the slide joints  10  along the stretch bars  110 , the backrest  114  is forced to move toward/away from the seat base  112  thereby adjusting the included angle between the backrest  114  and the seat base  112 .  
         [0033]      FIG. 8  shows another application of the slide joint of the present invention, wherein the slide joint  10  is slidably fit over an upright stem  202  of a sun shade device  200 . The sun shade device  200  has a radially extending support arm  204  having a first end attached to the coupling member  32  of the slide joint  10  in a rotatable manner and an opposite second end supporting a canopy  206 . A link  208  is arranged above the support arm  204  and has opposite ends respectively pivoted to the stem  202  and the support arm  204  for supporting the support arm  204  in an extended condition. By sliding the slide joint  10  along the stem  202 , the support arm  204  and thus the canopy  206  can be moved toward/away from the stem  202  for shielding different area below the canopy  206 .  
         [0034]     Also referring to  FIG. 9 , a slide joint constructed in accordance with another embodiment of the present invention, generally designated with reference numeral  310 , is shown. The slide joint  310  is a modification of the slide joint  10  discussed with reference to  FIGS. 1-6  and thus, the same reference numeral represent the same or similar parts, of which the description will be omitted for simplicity. The difference between the slide joint  310  and the slide joint  10  is that the coupling member  32  of the slide joint  10  is no longer rotatably attached to the cylinder  12 . In other words, in the slide joint  310 , the coupling member  32  is integrated with the cylinder  12 . This reduces the degrees of freedom of a second member that is jointed to a first member along which the slide joint  310  is fit, but simplifies the overall construction of the slid joint  310  and thus reducing the costs. The remaining parts of the slide joint  310  are identical to those of the slide joint  10  and the previous description applies.  
         [0035]     Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.