Abstract:
A safety catch using a sliding sleeve to close/open the opening of the hook thereof and a spring to support the sliding sleeve in the close position.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a catch and, more particularly, to a safety catch that is easy to operate and, can positively be set between the open position and the close position.  
           [0003]    2. Description of the Related Art  
           [0004]    Regular catches include two types, namely, the plastic catches and the metal catches. Metal catches are commonly used in key rings. Plastic catches are commonly used in gloves, backpacks, clothes, hats, and etc. Because of the disadvantages of complicated processing procedure, ease of being covered with rust, ease of scratching external objects, metal catches are less invited. Nowadays, plastic catches have been intensively used instead of metal catches in different fields.  
           [0005]    [0005]FIG. 8 shows a plastic spring catch A according to the prior art. This structure of plastic spring catch A comprises a link A 1 , a hook A 2  connected to one end of the link A 1 , and a spring tongue A 3 . The spring tongue A 3  has a fixed end connected to one end of the link A 1  adjacent to the hook A 2  and a free end stopped at the inner side of the hooked tip of the hook A 2 . When forcing the free end of the spring tongue A 3  inwards, the hook A 2  is opened for hooking. When released the hand from the spring tongue A 3 , the free end of the spring tongue A 3  is forced by the springy material property of the spring tongue A 3  to close the hook A 2  again. This structure of spring catch A is still not satisfactory in function because of the drawbacks bellows:  
           [0006]    1. When fastened to an object, the spring tongue A 3  tends to be forced inwards from the close position to the open position accidentally, thereby causing the caught object to slip away from the spring catch A.  
           [0007]    2. When the spring catch A fastened to a heavy object, the heavy weight of the caught object may force the spring tongue A 3  sideways, causing the spring tongue A 3  to be biased. In this case, the caught object may escape out of the spring catch A. When the spring catch A used to catch a precious object, for example, a notebook computer, the user may encounter a big loss.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention has been accomplished to provide a safety catch, which eliminates the aforesaid drawbacks. It is therefore main object of the present invention to provide a safety catch, which is easy to operate. It is another object of the present invention to provide a safety catch, which does not slip from the object to which the safety catch is fastened. To achieve these and other objects of the present invention, the safety catch comprises a link, a hook connected to one end of the link, the hook comprising a hooked hook element and a straight hook element, a sliding sleeve sleeved onto the straight hook element and moved along the straight hook element relative to the free end of the hooked hook element to close/open the opening between the straight hook element and the hooked hook element, and a spring member mounted in the straight hook element and stopped against a part inside the sliding sleeve to hold the sliding sleeve in the close position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is an exploded view of a safety catch according to the present invention.  
         [0010]    [0010]FIG. 2 is an elevational assembly view of the safety catch according to the present invention.  
         [0011]    [0011]FIG. 3 is a side plain view of the safety catch according to the present invention.  
         [0012]    [0012]FIG. 4 is similar to FIG. 2 but showing the hook opened.  
         [0013]    [0013]FIG. 5 is a side view, partially in section, of the present invention showing the hook closed  
         [0014]    [0014]FIG. 6 is similar to FIG. 5 but showing the hook opened.  
         [0015]    [0015]FIG. 7 is an applied view of the present invention, showing the link of the safety hook fastened to a fabric belt.  
         [0016]    [0016]FIG. 8 is an elevational view of a spring catch according to the prior art.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Referring to FIGS. 1, 2, and  3 , a safety catch in accordance with the present invention is shown comprised of a catch  1 , a spring member  24 , and a sliding sleeve  2 .  
         [0018]    The catch  1  comprises a link  11 , and a hook  12  pivoted to one end of the link  11 . The hook  12  comprises a first hook element  121  and a second hook element  122  connected in parallel to one end of the link  11 , and an opening  13  defined between the free end of the first hook element  121  and the free end of the second hook element  122 . The first hook element  121  is a straight bar having a track  1212  longitudinally extended to the free end, and two longitudinal sliding grooves  1211  longitudinally extended to the free end at two sides of the track  1212 .  
         [0019]    The sliding sleeve  2  is a split sleeve of substantially C-shaped cross section coupled to the first hook element  121  of the hook  12  and moved to and away from the free end of the second hook element  122  to close/open the opening  13  of the hook  12 . The sliding sleeve  2  comprises a longitudinally extended receiving open chamber  21  adapted to receive the first hook element  121  and the free end of the second hook element  122 , a stop block  22  transversely suspended in the longitudinally extended receiving open chamber  21  near one end, namely, the bottom end of the sliding sleeve  2  and spaced from the bottom end of the sliding sleeve  2  at a distance, a stub rod  221  perpendicularly extended from the stop block  22  and suspended in the longitudinally extended receiving open chamber  21 , and two longitudinal rails  23  bilaterally disposed inside the longitudinally extended receiving open chamber  21  corresponding to the longitudinal sliding grooves  1211  of the first hook element  121 .  
         [0020]    The assembly process of the present invention is outlined hereinafter with reference to FIG. 5 and FIGS. 1 and 2 again. The spring member  24  is sleeved onto the stub rod  221  of the sliding sleeve  2 , and then the sliding sleeve  2  is coupled to the first hook element  121  to force the spring member  24  into the track  1212  and the longitudinal rails  23  into the longitudinal sliding grooves  1211  respectively. When released the hand from the sliding sleeve  2 , the spring member  24  forces the sliding sleeve  2  toward the free end of the second hook element  122 , thereby causing the stop block  22  to be stopped at the free end of the second hook element  122  and the free end of the second hook element  122  to be engaged into the bottom end of the longitudinally extended receiving chamber  21  of the sliding sleeve  2 , and therefore the sliding sleeve  2  closes the opening  13  of the hook  12 .  
         [0021]    Referring to FIG. 6 and FIGS. 2, 4, and  5  again, when in use, the sliding sleeve  2  is moved upwardly away from the free end of the second hook element  122  along the first hook element  121  toward the link  11  to force the stop block  22  in the track  1212  against the spring member  24  and to open the opening  13 , for enabling the hook  12  to be fastened to the matching object. When the hook  12  fastened to the matching object, the sliding sleeve  2  is released from the hand, for enabling the spring member  24  to push the sliding sleeve  2  backward into engagement with the free end of the second hook element  122  to close the opening  13 .  
         [0022]    Referring to FIG. 7, the link  11  has a mounting ring  111  adapted for fastening to a belt  3 . After insertion of the belt  3  through the mounting ring  111 , the ends of the belt  3  are fixedly fastened to a part of a bag, clothes, etc. by stitches.  
         [0023]    In the aforesaid embodiment, the hook  12  is pivoted to the link  11 . Alternatively, the hook  12  can be fixedly connected to or formed integral with one end of the link  11 .  
         [0024]    A prototype of safety catch has been constructed with the features of the annexed drawings of FIGS.  1 ˜ 7 . The safety catch functions smoothly to provide all of the features discussed earlier.  
         [0025]    Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.