Patent Publication Number: US-2005129482-A1

Title: Retention device

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a retention device, more particularly to a retention device for a hook.  
      2. Description of the Related Art  
      Referring to  FIGS. 1 and 2 , a conventional hook retention device  1  is applicable on a wall surface or a ceiling  2  (see  FIGS. 3 and 4 ), and includes two anchor plates  11 ,  12 , a torsion spring  13 , a nut  14 , and a screw rod  15 .  
      Each of the anchor plates  11 ,  12  is generally U-shaped, and has a main wall  111 ,  121 , two opposite side walls  113 ,  123  that extend downwardly and respectively from two side edges of the main wall  111 ,  121  and that cooperate with the main wall  111 ,  121  to define a receiving space  112 ,  122 , a pair of aligning holes  114 ,  224  formed in inner ends of the side walls  113 ,  123 , and a groove  115 ,  125  formed in an inner end of the main wall  111 ,  121 . The grooves  115 ,  125  in the main walls  111 ,  121  of the anchor plates  11 ,  12  cooperate to form a circular hole  10  (see  FIG. 2 ) for extension of the screw rod  15  therethrough.  
      The nut  14  has a main body  141 , a central screw hole  142  for threaded engagement with the screw rod  15 , and two opposite extension parts  143  that extend outwardly from an outer periphery of the main body  141  and that extend respectively into the pair of aligning holes  114 ,  224  in the anchor plates  11 ,  12 .  
      The torsion spring  13  has a body portion  131  sleeved on one of the extending parts  143  of the nut  14 , and two opposite supporting portions  132  that extend outwardly from the body portion  131  into a respective one of the receiving spaces  112 ,  122  and that abut against a respective one of the main walls  111 ,  121 .  
      The screw rod  15  has a head portion  151  larger than that of the circular hole  10 , and a threaded shank portion  152  extending outwardly from the head portion  151 . The threaded shank portion  152  extends through the circular hole  10  and further through the screw hole  142  in the nut  14  so as to engage threadedly a screw hole  161  (see  FIGS. 2 and 3 ) in a hook  16  so that the screw rod  15  and the hook  16  form an intergral body.  
      Referring to  FIGS. 3 and 4 , to assemble the hook retention device  1  on the ceiling  2 , the user initially uses his two fingers to press the anchor plates  11 ,  12  toward each other against the elastic force of the torsion spring  13 , after which the hook retention device  1  is inserted into a through hole  21  in the ceiling  2 . Upon passing the anchor plates  11 ,  12  through the through hole  21 , the torsion spring  13  pushes the anchor plates  11 ,  12  apart so that the latter cannot be removed from the ceiling  2 . Then, the hook  16  is pulled downwardly, as shown by the arrow (I) in  FIG. 4 , so that bottom portions of the side walls  113 ,  223  of the anchor plates  11 ,  12  abut against the ceiling  2 . Afterwards, the hook  16  is rotated and tightened, as shown by the arrow (II) in  FIG. 4 , so as to move upwardly the screw rod  15  relative to the nut  14  until the hook  16  abuts against the ceiling  2  and is fixed on the same. An object (not shown) can be hung on the hook  16  at this time.  
      Although the aforementioned conventional hook retention device  1  can achieve its intended purpose, it has the following disadvantages:  
      1. When the hook  16  is rotated for tightening, the side walls  113 ,  123  of the anchor plates  11 ,  12  abut against the ceiling  2 . Since friction between the side walls  113 ,  123  and the ceiling  2  is small, the anchor plates  11 ,  12  are likely to rotate idly along with the hook  16 , thereby resulting in inconveniences during assembly of the conventional hook retention device  1 .  
      2. When the hook  16  bears a heavy load, it is easily damaged because only the nut  14 , which is a thin plate, serves as a load bearing point for the whole load, thereby resulting in a shorten service life for the hook retention device  1 .  
      3. Since the lengths of the anchor plates  11 ,  12  are limited, when they are to be inserted into the through hole  21  in the ceiling  2 , it is difficult for the fingers of the user to grasp effectively the anchor plates  11 ,  12  so that the anchor plates  11 ,  12  tend to be stretched slightly and outwardly by the torsion spring  13 . Due to the outwardly stretched anchor plates  11 ,  12 , the through hole  21  has to be enlarged so as to facilitate installation. However, the resulting outer appearance is unappealing.  
     SUMMARY OF THE INVENTION  
      Therefore, the object of the present invention is to provide a retention device that is simple and easy to assemble, that can support a heavy load, and that has an appealing appearance.  
      According to this invention, a retention device comprises a one-piece longitudinal anchor member, a nut, and a screw rod. The anchor member has longitudinally opposed first and second ends, a nut retaining part formed between the first and second ends, a through hole extending through the nut retaining part transversely of the anchor member, and an engagement surface around the through hole. The nut is movably received within the through hole. The screw rod extends through the through hole, and engages threadedly the nut. The screw rod is turnable between a folded position and an unfolded position. In the folded position, the screw rod is moved toward the first end. In the unfolded position, the screw rod is moved away from the first end. The nut is movable within the through hole between an engaging position and a non-engaging position. The nut engages the engagement surface in the engaging position when the screw rod is in the unfolded position. The nut is in the non-engaging position when the screw rod is in the folded position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:  
       FIG. 1  is a perspective view of a conventional hook retention device;  
       FIG. 2  is an exploded perspective view of the conventional hook retention device;  
       FIG. 3  illustrates how the conventional hook retention device is installed on a ceiling;  
       FIG. 4  illustrates how the conventional hook retention device is retained on the ceiling;  
       FIG. 5  is an exploded perspective view of the first preferred embodiment of a retention device according to the present invention;  
       FIG. 6  is a perspective view of an anchor member of the first preferred embodiment;  
       FIG. 7  is an assembled schematic partly sectional view of the first preferred embodiment, illustrating a folded position of a screw rod;  
       FIG. 8  is an assembled schematic partly sectional view of the first preferred embodiment, illustrating an unfolded position of the screw rod;  
       FIG. 9  is an exploded perspective view of the second preferred embodiment of the retention device according to the present invention;  
       FIG. 10  is an assembled schematic partly sectional view of the second preferred embodiment, illustrating a folded position of a screw rod; and  
       FIG. 11  is an assembled schematic partly sectional view of the second preferred embodiment, illustrating how a resilient element biases the screw rod away from the anchor member. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.  
      Referring to  FIGS. 5 and 6 , the first preferred embodiment of a retention device  100  according to the present invention is shown to comprise a one-piece longitudinal anchor member  3 , a nut  4 , and a screw rod  5 . The retention device  100  further has a hook  6  provided at one end of the screw rod  5 .  
      The anchor member  3  has longitudinally opposed first and second ends  35 ,  36 , a nut retaining part  32  formed between the first and second ends  35 ,  36 , an anchoring surface  34  extending from the first end  35  to the second end  36 , and a receiving space  33  formed in the anchoring surface  34 . The first end  35  is formed with a notch  351  that is in spatial communication with the receiving space  33 . The nut retaining part  32  protrudes outwardly from the anchoring surface  34  in a direction transverse to the anchor member  3 , and is formed with a through hole  321  extending through the nut retaining part  32  transversely of the anchor member  3 , and an engagement surface  322  (see  FIG. 8 ) around the through hole  321 . The anchoring surface  34  is toothed for effective engagement with a support to which the retention device  100  will be attached. A slot  324  is formed in the nut retaining part  32  at a side opposite to the anchoring surface  34 , and is in spatial communication with the through hole  321 .  
      The nut retaining part  32  has a multi-sided lateral wall  38  extending outwardly from the anchoring surface  34 , and an end wall  39  connected transversely to the lateral wall  38 . The lateral wall  38  is four-sided in this embodiment, and cooperates with the end wall  39  to confine the through hole  321 . The through hole  321  extends through the end wall  39 . The engagement surface  322  is formed on an inner side of the lateral wall  38  proximate to the end wall  39 . The nut retaining part  32  further includes an L-shaped aperture  323  which is in spatial communication with the through hole  321  and which extends from the end wall  39  to the lateral wall  38 .  
      The nut  4 , in this embodiment, is a hexagonal nut having a central screw hole  41 , and has a size smaller than the size of the through hole  321  so that the nut  4  is movable within the through hole  321  between an engaging position and an on-engaging position. However, the nut  4  should not be rotatable when in the engaging position. Accordingly, the nut  4  has an axially extending peripheral face  42 , and a radial face  43  connected to the peripheral face  42 . When the nut  4  is in the engaging position, the radial face  43  abuts against the end wall  39 , and the peripheral face  42  engages the engagement surface  322 . When the nut  4  is in the non-engaging position, the radial face  43  confronts the lateral wall  38 .  
      The screw rod  5  has a threaded shank portion  51 , which has one end  52  secured to the hook  6 , and an opposite end  53  that extends through the aperture  323  and the through hole  321  and that engages threadedly the nut  4  through the screw hole  41 . The screw rod  5  is turnable along the aperture  323  between a folded position (see  FIG. 7 ) and an unfolded position (see  FIG. 8 ). In the folded position, the screw rod  5  is substantially parallel to the anchor member  3 , and is located at the vicinity of the first end  35 . In the unfolded position, the screw rod  5  is substantially perpendicular to the anchor member  3 , and is located away from the first end  35 . The screw rod  5  is received in and engages releasably the notch  351  when the former is in the folded position.  
      Referring to  FIGS. 7 and 8 , during assembly, after the end  53  of the screw rod  5  is passed through the aperture  323  and the through hole  321  in the nut retaining part  32  and engages threadedly the nut  4 , the screw rod  5  is pulled downwardly so that the nut  4  is received in the through hole  321 . Then, the screw rod  5  is turned along the aperture  323  so as to be retained in the receiving space  33  and the notch  351 . At this time, the screw rod  5  is disposed at the folded position, and the nut  4  is in the non-engaging position. Note that the end  53  of the screw rod  5  which projects out of the through hole  321  should have a length smaller than the width (w) of the slot  324  so that the end  53  can turn into the through hole  321  through the slot  324  when the screw rod  5  is turned within the aperture  323 .  
      Thereafter, the screw rod  5  is inserted into a passage  71  in the ceiling  7  until the anchor member  3  passes through the passage  71 . When a slight external force is applied to move to and fro the screw rod  5 , through the weight of the anchor member  3 , the anchor member  3  moves away from the screw rod  5 . When the screw rod  5  is pulled downwardly relative to the ceiling  7 , the anchoring surface  34  of the anchor member  3  engages a top side of the ceiling  7 , and the nut  4  engages the engagement surface  322 . The screw rod  5  is disposed in the unfolded position at this time, and the nut  4  is in the engaging position where it engages the engagement surface  322  of the nut retaining part  32 . Finally, the hook  6  is grasped and rotated, as shown by the arrow (III) in  FIG. 8 , so as to rotate the screw rod  5  simultaneously. Because the anchor member  3  is already positioned on the top surface of the ceiling  7 , the nut  4  moves downwardly and threadedly along the through hole  321  relative to the screw rod  5 , as shown by the arrow (IV) in  FIG. 8 , without idly rotating with the screw rod  5 . An upper face of the hook  6  abuts against a bottom side of the ceiling  7  at this time so that the anchoring surface  34  of the anchor member  3  presses tightly against the top side of the ceiling  7 , thereby retaining stably the retention device  100  of the present invention on the ceiling  7 .  
      Referring to  FIGS. 9 and 10 , the second preferred embodiment of the retention device  100  according to the present invention is shown to be substantially similar to the first preferred embodiment. However, in this embodiment, the retention device  100  further includes a resilient element  8  disposed on the anchor member  3  between the nut retaining part  32  and the first end  35 . The resilient element  8  is made of a rubber material, and has a base body  81  adhered to the anchor member  3  proximate to the first end  35 , and a resilient part  82  that projects outwardly from the base body  81  and that has a dimension smaller than that of the base body  81 .  
      When the screw rod  5  is turned to the folded position, as shown in  FIG. 10 , it presses against the resilient element  8  so that the base body  81  and the resilient part  82  are in a compressed state. Then, the screw rod  5  is inserted into the passage  71  in the ceiling  7  until the anchor member  3  extends completely through the passage  71 . When an external force is applied to move to and fro the screw rod  5 , the screw rod  5  is released from the notch  351 . Simultaneously, the resilient element  8  springs back, and the anchor member  3  moves away from the screw rod  5 , as shown by the arrow (V) in  FIG. 11 . The screw rod  5  is now at the unfolded position.  
      The advantages of the retention device  100  of the present invention can be summarized as follows:  
      1. Because the anchor member  3  is positioned on the top side of the ceiling  7 , and because the anchoring surface  34  of the anchor member  3  engages the top side of the ceiling  7 , the anchor member  3  will not rotate idly and simultaneously with the hook  6  when the hook  6  is rotated to move upwardly. Therefore, installation of the present invention is relatively simple and stable.  
      2. Since the nut  4  is received in the through hole  321  in the nut retaining part  32  after assembly, and since the nut retaining part  32 , which is thicker and stronger than the nut  14  (see  FIG. 2 ) of the conventional hook retention device  1 , serves as a load bearing point, the retention device  100  of the present invention can bear a heavier load. As the retention device  100  is not likely to break when a heavy load is hung on the hook  6 , its service life is prolonged.  
      3. The screw rod  5  is easily turned between the folded position, where it is substantially parallel to the anchor member  3 , and the unfolded position, where it is substantially parallel to the anchor member  3 , thereby facilitating operation of the retention device  100 . Moreover, the size of the passage  71  in the ceiling  7  is only required to be large enough so as to accommodate extension of the nut retaining part  32  therethrough, and need not be enlarged further, thereby enhancing the appearance of the retention device  100  of the present invention.  
      4. Since less components are used in the present invention, assembly of the retention device  100  is easy. Moreover, after installation, the anchoring surface  34  engages firmly the ceiling  7  so that the retention device  100  is mounted stably on the ceiling  7 .  
      While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.