Patent Publication Number: US-6907645-B2

Title: Wire spring latch safety hook

Description:
RELATED APPLICATIONS 
     The present application is a continuation of and claims priority to U.S. patent application Ser. No. 10/268,539 for WIRE SPRING LATCH SAFETY HOOK filed Oct. 10, 2002 now U.S. Pat. No. 6,772,488, which claims the benefit of U.S. Provisional Application Ser. No. 60/329,258 filed Oct. 11, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to hooks, and, more particularly, to safety hooks which are used to attach a chain to another object; the safety hook having a safety latch over the hook opening which receives the object to which the hook is attached. The safety latch is generally designed to prevent the hook from becoming unintentionally disengaged from the object. For example, a safety chain on a trailer towed behind a motor vehicle is generally used to secure the trailer to the vehicle as a safety measure in case the trailer hitch becomes disengaged. The safety chains are generally secured to the under carriage of the vehicle using safety hooks having a safety latch. 
     Hooks have been used for years to attach chains to other objects. However, the wire formed or bent safety hooks having latches have not been manufactured with the simplicity one might employ to reduce costs and process steps, or so that the safety hook can easily accept a chain link through the chain link receiving opening. Accordingly, a new design of a safety hook is needed which will avoid these problems and provide a safety hook which can be easily attached to a chain without requiring a further attachment device and which has a simple design which is inexpensively produced. 
     It will be appreciated from the foregoing, therefore, that prior art devices and methods of making and using these devices present problems that are in need of solutions. It also will be appreciated that further enhancements of the cost effectiveness of the present invention and methods for making the same will provide needed efficiencies for consumers and manufacturers alike. The present invention provides solutions for these and other problems. 
     SUMMARY OF THE INVENTION 
     The present invention provides a safety hook having a wire spring latch. The wire spring latch  26  is a wire loop pawl. In preferred embodiments, the safety hook is made of a heavy gauge wire form material, which is preferably bent only in two places to form first and second ends, a chain link securing end and a hook opening end, respectively. The wire loop pawl is preferably a rod of elastically deformable material, bent to form an open loop and bent-over ends about which the pawl pivots with respect to the body of the safety hook when the latch is deformed and forced away from a distal end of the hook opening end of the safety hook. The bent over ends of the wire loop pawl are not coaxial. Each is inserted into one of two spaced apart apertures in the proximal end of the chain link securing end of the safety hook. In this way, the bent-over ends of the wire loop are kept in spaced-apart positions in which they are situated a distance from one another, thereby preventing pivoting with respect to the body of the safety hook, unless the wire loop is deformed. The wire loop may be deformed in such a way as to open the latch, but the latch is heavily spring biased up against an inside of the distal end of the chain opening end of the safety hook. The chain link securing end of the safety hook can receive a chain of the same thickness of material within the chain link securing end, and does not require any further attachment mechanism to attach to a chain. Once the chain link is received within the chain link securing end, the proximal end of the chain link securing end can be further bent or crimped to close the chain receiving opening between the proximal end of the chain link securing end and the closed side of the safety hook opposite the latch, thereby narrowing the chain receiving opening such that a chain link within the chain link securing end cannot be removed without deforming the safety hook. 
     In another embodiment of the present invention, a method of making a safety chain having a safety hook, the safety chain having a chain including at least one chain link is provided. In the preferred embodiment, the method includes the steps of providing a safety hook having: a continuous, unitary hook body formed from an elongated material generally having a uniform thickness; the hook body including first and second ends joined together by a generally straight section. The first end is a chain link securing end having a first turn section which interconnects the straight section with a proximal end which is angled generally back toward the straight section. The hook body has a chain link receiving opening between the straight side and the proximal end, wherein the distance between the straight side and the proximal end is greater than the thickness of the material of the hook body. The second end of the hook body has a second turn section extending away from the straight section and providing a curved hook portion including a distal end. The proximal end preferably has first and second spaced-apart wire receiving apertures. A wire spring latch is pivotally connected to the proximal end. The latch includes a wire form loop having two bent-over ends. The respective bent-over ends are pivotally engaged within the respective spaced-apart wire receiving apertures in the proximal end and the chain link receiving end has a gap between the straight section and a tip of the proximal section. The preferred method further including placing the chain link within the chain link securing end and crimping the proximal end toward the straight section such that the gap between the straight section and the tip of the proximal end is smaller than the thickness of the material. 
     In further embodiments of the present method, the step of providing a safety hook includes bending a length of standard wire form material to form the continuous, unitary hook body and further includes a step of bending a rod of elastically deformable wire form material to form the latch. In further embodiments, the step of providing a safety hook, further includes engaging the bent-over ends of the latch within the respective spaced-apart wire receiving apertures. 
     It will be appreciated that an object of the present invention is to provide an inexpensive safety latch which is made with great simplicity, and, therefore, at a reduced cost to the manufacturer. 
     It is a further object of the present invention to provide a safety latch wherein the latch is biased toward a closed position. It is a further object to provide a latch which is spring biased toward the closed position. It is yet another object of the present invention to provide a hook body which is easily engaged with a safety chain and manipulated to secure the safety chain within the chain link securing end of the hook body in order to prevent the safety hook from disengaging from the safety chain over time. 
     The above-described features and advantages along with various other advantages and features of novelty are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects attained by its use, reference should be made to the drawings, which form a further part hereof and to the accompanying descriptive matter, preferred embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings, in which like reference numerals refer to equivalent elements in a series of embodiments of the present invention: 
         FIG. 1  is a perspective view of the safety hook of the present invention before the chain link securing end is crimped to secure the chain link received in the chain link securing end; 
         FIG. 2A  is a rear elevation of the safety hook of  FIG. 1  before the chain link securing end is crimped; 
         FIG. 2B  is a rear elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped; 
         FIG. 3A  is a front elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped; 
         FIG. 3B  is a right side elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped; 
         FIG. 3C  is a left side elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped; 
         FIG. 3D  is a top side elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped; 
         FIG. 3E  is a bottom side elevation of the safety hook of  FIG. 1  after the chain link securing end is crimped. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and to  FIGS. 1 and 2A , a preferred embodiment of an uncrimped safety hook  10  of the present invention is shown. The uncrimped safety hook  10  has an uncrimped hook body  12  having first and second ends,  14  and  16 , and a wire spring safety latch  26 . The uncrimped hook body  12  is preferably made of wire form materials commonly used in the industry. As shown in  FIGS. 1 and 2A , the uncrimped hook body is a preliminary product which is preferably made using commonly used wire form bending and crimping techniques and the like. This preliminary product is made in anticipation of engaging an elongated strand (not shown) of weight bearing material such as a chain  50 , a wire (not shown), a multi-strand wire cable (not shown), a rope (not shown) or the like, although the present uncrimped safety hook  10  is preferably envisioned to be used with a chain intended to either tow vehicles or to provide a safety link between a vehicle and a drawn trailer or other such drawn equipment. To provide a completed product for actual use, an end of the elongated strand, preferably an individual chain link  48  at one end of a length of chain  50  is engaged in the first end  14  of the uncrimped hook body  12  and the hook body is crimped to secure the chain link  48  within the first end  14  of the hook body  12 . 
     Referring now also to  FIG. 2B , a completed safety hook  10 ′ is shown in which the completed hook body  12 ′ has been crimped to prevent the link  48  (shown in phantom) from disengaging from the first end  14 ′ of the crimped hook body  12 ′. 
     The first end  14  or chain link securing end  14  of the uncrimped hook body  12 , includes a first turn, which extends into a straight section  18  or a closed side  18 . The closed side  18  further extends away from the first turn  15  into a second turn  20 , or hook turn  20 , in the second end  16 , or hook opening end  16 . The uncrimped hook body  12  continues to extend around the hook turn  20  into a distal end  38  which is preferably a generally straight end as the wire form material of the hook body extends out of the hook turn  20 . As the wire form material of the uncrimped hook body  12  is traced back from the distal end  38  through the hook turn  20  of the second end, or hook opening end  16 , through the straight section  18  or closed side  18  of the uncrimped hook body  12 , and then through the first turn  15  of the first end  14  or chain link securing end  14 , the uncrimped hook body  12  ends in a proximal end  40 . The wire spring safety latch  26  is secured in two apertures,  42 ,  44  in the proximal end of the uncrimped hook body  12 . 
     As the wire form material of the uncrimped hook body  12  extends from the straight section  18  into and out of the first turn  15  within the chain link securing end  14  the wire form material preferably continues around a generally circular turn radius for more than about 180°, far enough so that the proximal end  40  of the chain link securing end  14  is bent back, so that it is angled toward the straight section  18  of the uncrimped hook body  12  to leave a narrow gap  78  between the straight section  18  and a tip  41  of the proximal end  40 . This gap  78  is preferably formed in such a way that the link  48  of the chain  50  or such other engaging end (not shown) of any other elongated strand (not shown) which is intended to be secured to the uncrimped safety hook  10  may be engaged with the uncrimped hook body  12  by being passed through the gap  78 . In the preferred embodiment, once the link  48  is passed through the gap  78 , the proximal end  40  of the uncrimped hook body  12  can be crimped against the straight section  18  to narrow the gap  78  so that the link  48  can no longer pass between the tip  41  of the proximal end and the straight section  18  of the hook body  12 . 
     Referring now particularly to  FIG. 2B , in which the preferred completed safety hook  10 ′ is shown, it will be appreciated that the gap  78 ′ between the tip  41 ′ of the proximal end  40  and the straight section  18 ′ of the crimped and completed safety hook  10 ′ is too narrow to allow the link  48  to pass out of the first end  14 ′. 
     Referring now again to  FIGS. 1 and 2A , it will be appreciated that the wire spring safety latch  26  is a wire loop pawl secured to the proximal end  40 . The wire loop pawl  26  is preferably made of a rod of wire form material that is elastically deformable material, preferably an elastic, deformable metal wire material, bent to form an open loop  28  and two bent-over ends  32 ,  34  about which the wire loop pawl pivots with respect to the uncrimped hook body  12 , when the wire spring safety latch  26  is forced inward toward the straight section  18  and away from the distal end  38  of the second end  16  or hook opening end  16  of the uncrimped hook body  12 . The bent-over ends  32 ,  34  of the wire loop pawl  26  are not coaxial, but rather non-concentric. Each is inserted into and engaged within one of two spaced-apart apertures  42 ,  44  in the proximal end  40  of the uncrimped hook body  12 . As is evident in the drawings, the respective apertures  42 ,  44  are not only spaced apart along the length of the proximal end  40 , but they are also displaced side-to-side along the length of the proximal end  40 , such that a first aperture  42  of the two spaced-apart apertures  42 ,  44  is closer than a second aperture  44  of the two spaced-apart apertures  42 ,  44  to a first turn surface  54  which extends generally along an inside  15   a  of the first turn  15 . The second aperture  44 , on the other hand, is closer to a second surface  56 , opposite of the first turn surface  54 , with respect to the proximal end  40  as shown in FIG.  2 A. When the proximal end  40  is crimped as discussed above, so that the proximal end  40 ′, as shown in  FIG. 2B , is closer to the straight section  18 ′ than it was before, and the gap  78 ′ is narrowed from the gap  78  shown in FIG.  2 A. Also, the first and second apertures  42 ,  44 , although spaced apart from side-to-side with respect to an axis  58  of the proximal end  40 . 
     When the proximal end  40  is crimped to take the position of the proximal end  40 ′, shown in  FIG. 2B , and to narrow the gap  78 ′ to secure the link  48 ′ within the chain link securing end  14 ′, the respective first and second apertures  42 ′,  44 ′ are generally positioned equidistant from the straight section  18 ′ and the wire look pawl  28 ′ is believed to remain forcefully biased against an inside surface  37 ′ of the distal end  38 ′ of the crimped hook body  12 ′. 
     In order to open the completed wire spring latch safety hook  10 ′ to permit entry past the wire spring safety latch  26 , the wire loop pawl  26  must be forced away from the inside surface  37 ′ of the distal end  38 ′, which deforms the wire spring pawl  26 ′ (as shown in phantom in FIG.  2 B), thereby increasing the degree to which the wire spring pawl is biased toward the distal end  38 ′. Because the bent-over ends  32 ′,  34 ′ of the wire loop pawl  26 ′ are kept in spaced-apart positions within the proximal end  41 , the wire loop pawl or wire spring safety latch  26  is prevented from pivoting with respect to the completed hook body  12 ′ of the safety hook  10 ′, unless the wire loop  28 ′ is deformed because the wire loop pawl  26  is preferably made from a deformable, but elastic, wire form material, the wire spring safety latch  26 ′ will be biased toward the distal end  38 ′ when it is sufficiently pivoted with respect to the completed hook body  12 ′ to open the safety hook end  16 ′ in the manner shown in phantom in FIG.  2 B. The wire loop  28 ′ may be deformed in this way, so as to open the latch  26 ′, but the latch  26 ′ will be heavily spring-biased toward the inside  37 ′ of the distal end  38 ′. 
     Further reference is now made to  FIGS. 2B-3E , in which several views of a safety hook  10 ′ of the type shown in  FIGS. 1-2B , where the chain link receiving end  14 ′ has been further crimped to narrow the gap  78 ′ between the proximal end  40 ′ and the closed side  18 ′ so as to secure the chain link  48  (shown in phantom in FIG.  2 B). 
     In preferred embodiments, the hook body  12  is preferably formed of a unitary piece of material having a generally uniform, circular cross-section of ⅜″, {fraction (5/16)}″ or ¼″ diameter. The unitary piece of material is preferably a die formed into the shape shown. Regardless of the diameter or cross-sectional shape of the hook body  12 , the chain opening distance  78  should be as large or larger than the thickness of the material for hook body  12 . This allows the hook  10  to receive a link  48  of chain  50  of similar size and thickness to the material for hook body  12 . The hook body  12  and the latch  26  are all preferably formed of zinc plated steel. Hook body  12  and latch  26  are preferably heat treated for strengthening. 
     It is to be understood that, even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts, within the broad principles of the present invention, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.