Abstract:
One embodiment of an improved gate latch pull cable of the type being made of metal for durability and having a one-piece clevis clip secured to one end for easy attachment to a gate latch, and a pull loop secured with a cable sleeve on the other end for securely grasping the cable. The clevis clip incorporates an integral clevis pin eliminating loose parts, and a fillet transition to the cable to prevent it from catching on edges. Surrounding the cable is a tapered return-spring which assists in gate latch closure, and a spring cup which fits in a gate post hole for centering the large diameter of the spring over the hole. The small diameter of the spring is proximal to the clevis clip, and lightly pushes against a gate latch cam. The tapered spring coils fit inside each other when compressed allowing the gate latch to fully open.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application Ser. No. 61/170,770 filed Apr. 20, 2009 by the present inventor. 
    
    
     BACKGROUND 
     Prior Art 
     The following is a tabulation of some prior art that presently appears relevant: 
     
       
         
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 U.S. Patents 
               
             
          
           
               
                   
                 Pat. No. 
                 Kind Code 
                 Issue Dates 
                 Patentee 
               
               
                   
                   
               
               
                   
                 3,266,831 
                   
                 Aug. 16, 1966 
                 Banse 
               
               
                   
                 3,433,518 
                   
                 Mar. 18, 1969 
                 Foltz 
               
               
                   
                 5,078,438 
                   
                 Jan. 07, 1992 
                 Bieganski 
               
               
                   
                 5,358,292 
                   
                 Oct. 25, 1994 
                 Van Wiebe et al. 
               
               
                   
                 5,498,041 
                   
                 Mar. 12, 1996 
                 Bezzerides et al. 
               
               
                   
                 6,170,892 
                 B1 
                 Jan. 09, 2001 
                 Lantiegne 
               
               
                   
                   
               
             
          
         
       
     
     Gravity style gate latches are among the most commonly used residential gate latches. They are also referred to as automatic gate latches. They latch automatically when a gate is closed and hold the gate in the closed position. Closing the gate causes the latch mechanism to rise. Gravity then pulls it down, latching the gate closed. 
     Originally automatic gate latches were intended to be opened from the opposite side of the gate with a string. For example, U.S. Pat. No. 3,433,518 to R. E. Foltz (1969) shows the use of a string to open the latch. Due to the constant exposure to the outdoor elements, the string deteriorates, weakens and breaks. Sometimes gate latches stick or bind, requiring more pulling force to open than a string can offer. This makes opening a gate unreliable. Once the string is broken the gate can only be opened by reaching over to unlatch it or going around the house to open it from the back side. If the gate is tall or the person is short, reaching over the gate may not be an option. In addition, the string is limited to a pulling force and cannot provide any pushing assistance to ensure a positive closure. If the gate is slammed closed the latch mechanism cannot act quickly enough to make a positive latch and the gate bounces open. 
     Despite many attempts to create a better device to open automatic gate latches from the opposite side, the string remains the standard and by far the most commonly used device. 
     As can be seen, there is a need for a gate latch pull cable that is stronger, more durable and more reliable. To compete with a string it also needs to be inexpensive, easy to install and easy to use. To offer more value and security it needs to assist in positive latching. 
     Several types of gate latch pull cables have been proposed: U.S. Pat. No. 5,358,292 to Van Wiebe et al. (1994) is a gate latch pull which requires a significant amount of tooling to manufacture all of the plastic components. This increases the manufacturing cost and complexity, making it difficult to compete with a string. It is made of plastic, which will deteriorate in constant exposure to sunlight. This makes it prone to breakage and unreliable. It pulls up on the gate latching mechanism rather than pulling straight back, making it harder to pull and harder to open the latch fully. In addition, the spring pressure is too strong and causes the gate to bounce back open if the gate is not closed hard enough. This design is an attempt to solve the positive latching problem, but actually makes it worse because of the excessive spring pressure. Furthermore the spring and cable pull used in his design bunches up in one embodiment and bends more than 90 degrees in another. Both of these designs require excessive pull force resulting in an inconsistent latch mechanism release and in some cases a broken plastic cable. 
     U.S. Pat. No. 6,170,892 to Lantiegne (2001) does not offer the strength, durability, reliability or automatic positive latching capabilities. It is not designed for a significant pull force if the gate latch is stuck or binding. With a significant pull force, Lantiegnes&#39; cable pull will slide off of the latch mechanism. Even with UV additives, plastic eventually breaks down in sunlight and overtime the gate latch pull will weaken and break. The other attachment methods in his patent are also prone to breaking with constant exposure to sunlight. Whether his gate latch pull is made of plastic or metal it is still lacking an automatic spring force to assist in the positive closure of the gate latch. A gate latch pull without a spring return acts as a dampener because of the additional weight and friction. This additional drag slows down the gate latch action and hinders positive gate latch closure if the gate is closed quickly. 
     U.S. Pat. No. 5,498,041 to Bezzerides et al. (1996) requires a separate spring on the latch to assist with latch closure rather than having an independent spring as part of the cable pull. This makes the cable pull dependent on the latch. If the automatic latch does not have a return-spring the cable will not offer return assistance and will also act as a damper. Some of the gate latch pull parts in Bezzerides patent are very small, loose parts that are easy to drop and tedious to install. Additionally, Bezzerides patent shows a push pad on the gate latch. If the gate latch does not have a push pad the sharp ends of the small gate latch pull parts will cause discomfort to the individual pushing the latch open. Stanley Co., one of the largest suppliers of gate hardware, offers an automatic gate latch #SP-1101 that does not have a push pad. 
     SUMMARY 
     In accordance with one embodiment a gate latch pull cable comprises a cable having a pull loop at one end held in place with a cable sleeve, a clevis clip incorporating an integral attachment pin on the other end, a tapered return-spring and a self aligning spring cup surrounding the cable at the clevis end. 
     ADVANTAGES 
     Accordingly several advantages of one or more aspects are as follows: to provide a gate latch pull cable that is easy and affordable to manufacture, that will allow a retail price point that is in-line with the cost of the gate latch, that is easy to install, that is strong, durable and reliable, that will stand up to the elements, that assists in positive gate latch closure, that eliminates gate latch bounce back, and is easy to pull. Other advantages of one or more aspects will be apparent from a consideration of the drawings and ensuing description. 
    
    
     
       DRAWINGS 
       Figures 
         FIG. 1 : is a perspective view of the invention  10 . 
         FIG. 2 : is a side view of the invention  10 . 
         FIG. 3 : is a front view of the invention  10 . 
         FIG. 4 : is a top view of the invention  10 . 
         FIG. 5 : is a side view of the invention  10 . 
         FIG. 6 : is a detail perspective view illustrating the clevis clip  16   
         FIG. 7  is a view of the tapered spring in an extended configuration. 
         FIG. 8  is a view of the tapered spring in a collapsed configuration. 
     
    
    
     DRAWINGS 
     Reference Numerals 
     
         
         
           
               10  overall invention 
               12  gate latch assembly 
               14  gate latch cam 
               16  clevis clip
             16   a  filet     16   b  barrel     16   c  flat side     16   d  clevis pin     16   e  opposing flat side     16   f  hole   
         
               18  tapered return-spring 
               20  spring cup 
               22  cable 
               24  cable sleeve 
               26  pull loop 
               28  gate post 
               30  gate 
               32  gate latch bar 
           
         
       
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is my present contemplated mode of carrying out an exemplary embodiment of the invention. The description is not to be taken in a limiting sense, but is made for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     I presently contemplate for this embodiment an elongated cable  22  that passes through a hole in a gate post  28 . The cable comprises a pull loop  26  at a first end which is secured with a cable sleeve  24 . A clevis clip  16  is secured at the second end. The clevis clip comprises a fillet  16   a , a barrel  16   b , a flat side  16   c  and a clevis pin  16   d  which is affixed to the flat side  16   c . An opposing flat side  16   e  has a hole  16   f  to receive the clevis pin  16   d . The clevis clip  16  is attached to a gate latch cam  14  which pivots inside a gate latch assembly  12  and latches on to a latch bar  32  which is attached to a gate  30 . A tapered return-spring  18  surrounds the cable  22  and is situated proximal to the gate latch assembly  12 . The larger diameter of the tapered return-spring  18  rests in a spring cup  20  which surrounds the cable  22  and is situated in the hole in the gate latch post  28 . The smaller diameter of the tapered return-spring  18  presses against the gate latch cam  14 . 
     Operation—Referring to  FIGS. 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 , and  8 . 
     An exemplary embodiment may be made and used according to the following description. 
     The present invention provides a mechanism to open the gate latch from the outside of the gate. The pull loop  26  in cable  22  is grasped and pulled back which pulls on the clevis clip  16  compressing the tapered return-spring  18  and opening the gate latch cam  14  fully so the gate latch bar  32  attached to gate  30  can be released and gate  30  is opened. Once the gate  30  is opened, the pull loop  26  is released and the tapered return-spring  18  assists the gate latch cam  14  to return to the closed position. Next, the gate  30  is closed and the gate latch bar  32  pushes the gate latch cam  14  up and against the light force of the tapered return-spring  18  and then the tapered return-spring  18  pushes back and assists the closure of the gate latch cam  14  which captures the gate latch bar  32 , securing the gate  30  closed. 
     Cable  22 : The gate latch pull cable  22  may be approximately 14″ long, is made of multiple strand, flexible, 1/16″ inch in diameter, stainless steel cable. The cable has a pull loop  26  on one end for grasping it. The cable  22  may be 304 stainless steel, 7×7 stranded wire available at West Coast Wire and Rigging, 597 85th Ave., Oakland, Calif. 94621. The cable may be cut to the desired length using a Felco cutter, model number C-7 available from Lexco Cable Mfg., 7320 West Agatite Ave., Norridge, Ill. 60706. 
     Pull Loop  26 : The pull loop  26  in the cable may be approximately 2″ long and held in place by crimping the cable sleeve  24  onto the cable. The pull loop  26  can be formed by hand and the cable sleeve  24  is slid over the cable and may be crimped with a standard cable crimping tool number 1-3-SBHS, available from Lexco Cable Mfg., 7320 West Agatite Ave., Norridge, Ill. 60706. 
     Cable sleeve  24 : The cable sleeve  24  may be made from copper and crimped onto the cable  22  to hold the pull loop  26  in place. The cable sleeve  24  is a standard product #S-10-001 available from US Rigging, 4001 W. Carriage Dr. Santa Ana, Calif. 92704. 
     Clevis Clip  16 : The clevis clip  16  is small enough to fit through a ¼″ diameter hole in the gate post and a ¼″ hole in the spring cup. It may be hardened, high carbon steel or stainless steel which may be silver soldered onto the end of the cable  22  opposite the pull loop  26 . Stay-Brite silver solder #SB11 may be used in conjunction with Stay-Clean soldering flux #40004 which are both available from J.W. Harris Co., Inc., Mason, Ohio 45040. The clevis clip is soldered to the cable by sliding the barrel  16   b  of the clevis clip  16  over the cable  22 . The soldering flux is applied where the cable  22  meets the clevis clip  16 . Heat is applied, with a small butane torch such as the Bernz-o-matic #019133ST2200T, to the same area until the flux starts to bubble then the solder is dabbed on until it melts and wicks up into the barrel  16   b  of the clevis clip  16 . After the solder is cooled with a few drops of distilled water, flux and heat are applied again and another dab of solder is applied to create a fillet  16   a  between the cable  22  and end of the barrel  16   b  on the clevis clip  16 . To attach the clevis clip  16  to the gate latch cam  14 , the flat side  16   c  and the opposing flat side  16   e  of the clevis clip  16  are spread apart and the clevis pin  16   d  is lined up over the hole in the gate latch cam  14  and released causing the pin to go through the hole in the gate latch cam  14  and through the hole in the opposing flat side  16   e  of the clevis clip  16  attaching it securely to the gate latch cam  14 . The clevis clip  16  is a standard product. It is part number  112 . It is called a 2-56 solder kwik-link available from Du-Bro Products, 480 Bonner Rd., Waconda, Ill., 60084. It is made by forming sheet metal with dies. Once the clevis clip  16  has been formed it is heat treated for strength and then plated with Nickel. 
     Tapered return-spring  18 : The tapered return-spring  18  may be made of stainless steel. It is conically shaped so it can completely collapse on itself and not interfere with the gate latch cam  14  being pulled all the way open. When the tapered return-spring  18  is completely collapsed (see, e.g.,  FIG. 8 ), the coils of the spring fit inside of each other and it can be compressed down to the thickness diameter of the spring wire, which may be about 0.020″.  FIG. 5 , and more particularly  FIG. 8 , shows the tapered return-spring&#39;s  18  ability to fully compress while the cable  22  is pulled straight back, in direct alignment with the attachment hole in the gate latch cam  14  that the clevis clip  16  attaches to. The tapered return-spring  18 , in one example, is a custom spring and can be made to specification by standard spring manufacturing techniques by various spring manufacturing companies such as Century Spring, 222 16 th  St. Los Angles, Calif. 90015. Century Spring has assigned this custom made tapered return-spring  18  part number SPC47333. 
     Spring Cup  20 : The spring cup  20  is used to hold the large diameter of the tapered return-spring  18  so it stays centered over the hole in the gate post  28 . The spring cup  20  may be made of mild steel, case hardened to reduce friction and then plated with nickel to prevent rust. The spring cup  20  may be manufactured on a lathe to specifications by a machine shop such as Edward Koehn Company Inc., 820 Folger Ave, Berkeley, Calif. 94706. 
     Advantages 
     From the description above, a number of advantages of one embodiment of my gate latch pull cable become evident:
         (a) Easy and inexpensive to manufacture: The gate latch pull cable is easy to make. It doesn&#39;t require extensive tooling. The cable, cable sleeve and clevis clip are “off the shelf” commercially available parts. Only the tapered return-spring and the spring cup are custom parts and they can be made with popular, standard manufacturing techniques. Because of this, the gate latch pull cable can be made at a competitive and reasonable price point.   (b) Strong, durable and reliable: All Steel construction makes it strong, durable and reliable. It won&#39;t break down in sunlight like a string or a plastic pull. If the gate latch binds, the cable can be pulled hard without worry of breaking.   (c) Better security: The tapered return-spring provides a light return force to the gate latch cam which ensures positive gate latching and eliminates gate bounce back. It also allows the gate latch cam to fully open because the tapered return-spring&#39;s coils fit in-between each other and can completely collapse. A regular coil compression spring does not have this capability because the spring coils stack up on each other when compressed. The completely collapsing tapered return-spring also allows the pull force to be directly behind the gate latch cam attachment hole. The direct alignment provides a consistently smooth and even pull on the gate latch cam. The tapered return-spring is strong enough to overcome the additional weight, dampening effect and friction caused by adding a gate latch pull to the gate latch cam but not strong enough to require the gate to be slammed to overcome the spring force.   (d) Easy to install: The one piece Clevis Clip with the affixed, integral clevis pin allows for a quick, easy, “no tools required” attachment to the gate latch cam. It has no small loose parts to drop or lose and it doesn&#39;t have any sharp parts, like a clevis pin clip, to get cut on. Its compact size allows for a small hole to be drilled in the gate post. Because it is made of hardened, high carbon steel it is strong and will not yield from a human pull force.       

     CONCLUSION, RAMIFICATIONS AND SCOPE 
     Accordingly, the reader will see that the gate latch pull cable can be used to replace the most commonly used devise which is an ordinary string. The low cost to manufacture, the durability, the ease of installation and the spring assisted closure make it an obvious choice over a string. The fact that more than 15,000 gate latch cables of this embodiment have been sold through 192 hardware stores during the term of the Provisional Patent are a clear testimonial to the need and acceptance of this design. The use of the tapered return-spring, the clip-on, one piece clevis and the all metal construction are the primary attributors to the success of the 15,000 gate latch cable pulls that have been sold.