Patent Publication Number: US-4253693-A

Title: Safety device for cable climbers, hoists and winches

Description:
SUMMARY 
     This invention is based upon U.S. Patent Office Disclosure Document No. 076671 dated Dec. 22, 1978. The safety device for cable climbers, hoists and winches of this invention prevents insertion of wrong size wire. Generally as known in the prior art insertion of larger diameter wire is prevented by making a hole of the right size through which the cable must pass. However many accidents have resulted by insertion of a smaller diameter weaker wire. It is the object of this invention to prevent insertion of smaller diameter wires than the size for which cable climber, hoist or winch was originally designed. Other objects of this invention reside in its design simplicity low cost and reliability as will become apparent from the detailed description of the preferred embodiment. 
     An exhaustive patent search including class 182 subclass 112 and interviews with many examiners was conducted and but no relevant prior art was uncovered. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cutaway elevation view of the front of the front of the safety device of this invention. 
     FIGS. 2a, 2b and 2c, respectively, show top plan, right hand side elevational and front elevational views of the guide block assembly. 
     FIGS. 3a, 3b and 3c, respectively, show cutaway front elevational, right hand side elevational and top plan views of the gate block which in turn is housed within the guide block. 
     FIG. 4 is a front elevational view of the pivot arm. 
     FIG. 5 is a pictorial view of the spring. 
     FIGS. 6a and 6b, respectively, show the operation of this invention when right and smaller sizes of wire are inserted. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of this invention comprises a guide block 10, a gate block 20, a pivot arm 30, a blade spring 40 and plurality of roll pins. The guide block 10 is housed in the climber, hoist or winch in the path of the wire. FIG. 1 shows a view of the safety device of this invention. FIGS. 2; a, b, c show top, side and front views of the guide block 10, showing plurality of holes and recesses. FIGS. 3; a, b, c, show the front, side and top view respectively of the gate block 20. FIG. 4 shows plan view of the pivot arm 40 having a hole 32 and a slot 34. FIG. 5 shows blade spring which is used to put pressure on gate block 20 in the longitudinal direction. FIGS. 6; a, and b show the operation of the safety device of this invention when the right and the wrong size wires are inserted in the safety device of this invention. 
     The gate block 20 is housed in the guide block 10 such that the guide block can move transversely in either direction. A hole 12 in the guide block and a hole 22 in gate block of diameter same as hole 12 is designed to be larger than the maximum diameter of the cable for which the cable climber, hoist or winch is designed. The physical alignment of the gate block 20 in guide block 10 is such that the holes 12 and 22 can be aligned when the cable of the right size is inserted. 
     The guide block 20 is also connected to a pivot arm 30 with lever arrangement that a travel of X amount in the pivot arm 30 results in travel of 4X in the gate block 20 relative to the guide block 10. The pivot arm 30 is mounted such that normally it blocks a portion of the hole 12 at an angle of 30 degrees. 
     The gate block 20 in addition to having hole 22 also has a recess slot 24 and a hole for roll pin 50. Similarly guide block 10 also has two additional holes for roll pins 50 (Full Length) and 52 partial length. In addition a housing 90 may be used to mount safety device of this invention in alignment with cable 100 so that cable cannot enter hole 12 in guide block 10 except in a straight line. Following is a listing of the components used in the preferred embodiment along with their specification arranged in the ascending of the reference numerals. 
     10 Guide Block 
     12 Hole in the guide block somewhat larger than the diameter of the right size cable and in alignment with the cable 
     20 Gate block mounted inside guide block and is free to move longitudinally 
     22 Hole in guide block of same diameter as hole 12 
     24 Shallow bore in the gate block for trapping cable of the wrong (weak) (smaller) size 
     30 Pivot arm 
     32 Hole in pivot arm 
     34 Slot in pivot arm 
     40 Spring 
     50 Full length roll pin 
     52 Partial length roll pin 
     90 Top guide housing 
     100 Cable 
     OPERATION 
     Normally the pivot arm 30 blocks such a small portion of the hole 12 that cables of smaller size can pass through without disturbing the pivot arm. This is ensured by the alignment between the guide block 10 and the top guide housing 90 which is mounted generally above said guide block 10. Furthermore blade spring 40 maintains bias on pivot arm 30 via gate block 20 such that accidental movement does not clear this path 12, 22 through which cable 100 must pass. As the rigid cable of smaller size advances past the pivot arm 30 it stops at the bottom of and within recess bore 24 in the gate block 20, thereby making it impossible for gate block 20 to move in either direction and also making it impossible for smaller size cable 100 to advance further or enter through guide block 20. 
     When the proper size cable is fed into the guide block hole 12, it strikes pivot arm 30 at an angle of 30 degrees thereby causing pivot arm 30 to move X amount which is translated into a linear movement of 4X in the gate block 20 relative to guide block 10. This aligns hole 22 with hole 12 in the gate block and guide block respectively, allowing the right size cable to pass through freely. 
     With this description the inventor Leonard W. Gish merely wished to establish date of conception and reserves the right to make numerous changes in the patent application consistent with the concept described herein.