Abstract:
A latch including a handle operative only in response to a grasp-like pull. In a preferred embodiment, the handle comprises a rod bent into a general C-shape to provide a pair of ends. The handle is pivotally mounted. Operation of the handle pivots a first handle end in an arc to move a latch bolt approximately parallel to the chord of said first handle arc to move the latch bolt from an engagement to a disengagement position. The second end of the handle normally closely abuts the latch casing to preclude operation of the handle by a push.

Description:
BACKGROUND AND FIELD OF THE INVENTION 
     Briefly, the invention relates to a latch, in general, and in particular to a farm gate latch. 
     An object of the invention is to provide a farm gate latch ready operation of which by a farm animal is frustrated. 
     A further object of the invention is a farm gate latch which is readily operable by a person either side of the gate. 
     Another object of the invention is a farm gate latch for use with a multi-panel farm gate. 
     An additional object of the invention is a farm gate latch for use with a pipe, multi-panel farm gate. 
     Yet a further object of the invention is a pulloperated farm gate latch. 
     Still another object of the invention is a farm gate latch having a planar, pivotable handle, rotation of which is in the plane of the handle and in the direction from which it is opened to provide a pull-operated farm gate latch. 
     An object of the invention is a farm gate latch having a handle operable by a semi-grasp or full grasp, such as is typically employed by a person. 
     Another object of the invention is a farm gate latch the handle mechanism of which has a significant mechanical advantage for opening the latch. 
     BRIEF DESCRIPTION OF INVENTION 
     The invention comprises a farm gate latch having a handle and a movable member such as a bolt for mating engagement with a catch. The handle has a configuration which requires application of a grasp-like force to operate the handle to open the latch. Such a handle is readily operable by digital animals, such as man, but operated only with great difficulty, if at all, by farm animals such as cattle and horses. Both a handle configuration which has an end which abuts other structure and a handle which has a recessed handle require application of a grasp-like pull force and are unresponsive to push forces, the latter of which forces are readily applied by non-digital farm animals, such as, for example, cattle, horses, pigs and sheep. 
     In a specific preferred embodiment of the invention, a farm gate latch comprises a pair of elongate handles, a bolt, a casing for housing the bolt, and a bias spring which holds the handles in a normal position, namely with a first end against a strike on the bolt and with the handle second end in abutment against the casing. Each handle is a generally C-shaped rod. The rods are each pivotally secured to a mounting yoke which is attached to the casing. The end of each rod forming the handle first end extends into the casing to operate the bolt. The bolt transmits a force from the bias spring to the handle first end and the force operates through the handle pivot point to hold the handle second end in abutment against the casing. 
    
    
     BRIEF DESCRIPTION OF DRAWING 
     FIG. 1 is a perspective view of a preferred embodiment of a gate latch according to the present invention shown attached to a pipe gate; 
     FIG. 2 is a side plan view of a preferred embodiment of a gate latch according to the present invention; 
     FIG. 3 is a sectional view of the latch taken along line 3--3 of FIG. 2; 
     FIG. 4 is a layout view of handle mounting yokes of the latch illustrated in FIG. 2; 
     FIG. 5 is a perspective view of an alternative embodiment of a gate latch embodying the broad principles of the present invention; and 
     FIG. 6 is a fragmentary view of an embodiment of a gate latch according to FIG. 1 incorporating a lock mechanism. 
     In FIGS. 2, 3, and 4, the drawings are approximately to scale. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     A preferred embodiment of the present invention is shown generally as 10 in FIG. 1, a perspective view. Latch 10 comprises a pair of handles 12, although only a single handle is required, and a bolt 14 which is a moveable member for engaging a catch 16. Bolt 14 is housed within a casing 18 and handles 12 are attached to casing 18 by attachment yokes 20. Latch 10 includes vertical member and horizontal member attachment means which for the particular embodiment consist of a flat plate 22, curved plate 24, bolts 26, an elongate strip 28, and another bolt 30. Latch 10 is shown attached to a pipe, multipanel, farm gate having a top horizontal panel 32, first interior horizontal panel 34, second interior panel 36, vertical panel 38, latch post 40, and a bottom horizontal panel (not shown). 
     FIG. 2 is a side, plan view of latch 10. Attachment yoke 20 is shown to comprise a generally U-shaped channel to which a handle 12 is pivotally attached by means of a rivet 42 which serves as a pivot pin. An aperture 43 in casing 18 provides for drainage of fluids from the casing. Bolt 14 and bolts 26 each pass through apertures in plate 22, vertical member 38 and plate 24. 
     FIG. 3 is a sectional view of latch 10 taken along line 3-3 of FIG. 2, illustrating in particular the detailed construction of casing 18, and bias means carried therein in the form of a spring 44. Spring 44 for the particular illustrated embodiment serves a dual function; namely, a first function of holding handles 12 in the closed position shown and a second function of holding bolt 14 in an engagement position. Normally the handle first ends 46 are held in position to operate bolt 14 from a normal engagement position to a position of disengagement and the handle second ends 48 are held in abutment with casing 18. Casing 18 includes a cylinder 50, and a cap 52. A strike is provided on bolt 14 in the form of a washer 54 against one side of which first handle ends 46 operate to move bolt 14, and on the other side of which rests an end of spring 44. Because spring 44 is shorter than the length of the casing rearward of handles 12, a washer 56 and spacer sleeve 58 are provided which maintain spring 44 normally in sufficient tension to hold handles 12 with their second ends normally in abutment against casing 18. 
     FIG. 4 is a layout view of attachment yokes 20 and attachment means flat plate 22. Yokes 20 and plate 22 may be formed from a piece originally in the shape of a rectangle by shearing the rectangle corners, punching or drilling the apertures, and slitting to provide end pieces which are then folded into U-shaped channels to form the yokes 20, leaving the centerpiece as a flat plate 22. Apertures 60 are provided for passage therethrough of a rivet 42. 
     A latch 10 suitable for use, and in fact used, on a 16 foot long, four panel, 2 inch diameter, steel pipe gate was constructed using the components as set forth in the following Table I. 
     TABLE I 
     Handle 12: 1/2 inch diameter mild steel rod 81/2  inches long having a first section about 21/8  inches long, second section about 31/4  inches long, and a mid-section intermediate the first and second sections about 31/8  inches long; and having a 1/4 inch diameter hole at about the juncture of the first end section and mid-section; 
     bolt 14: a 10 inch length of 5/8 inch diameter case hardened steel having a slightly beveled end to facilitate engagement with a catch; 
     catch 16: mild sheet steel, 3/16 × 33/8  ×  111/4 formed into an equilateral triangle having a 51/2  inch base and the ends of which are notched to form, when joined, an opening 5/8 inch wide by 23/4  inch long (the long dimension of the opening provides a built in adjustment for sagging gates, whether it be merely from age, frost heaval, or whatever reason); two 5/16 inch holes in the base are accessible through the opening for mounting the catch by a pair of 5/16 inch by about 3 inch lag bolts or by 5/16 inch machine bolts, nuts, and lock washers; 
     flat plate 22: 1/16 inch mild sheet steel, 15/8  inch by 37/8  inches having an 11/16 inch diameter hole centered in the plate for passage therethrough of bolt 16 and a pair of 5/16 inch holes on the same spacing and alignment as the 5/16 inch holes of plate 14; 
     curved plate 24: 1/8 × 17/8  × 37/8  inch mild sheet steel, radiused to conform with a 2 inch diamter pipe; including holes the same in size and alignment as plate 22; 
     bolts 26 and 30: 1/4 by 23/4  inch machine bolt, including nut and 1/4 inch lock washer; 
     strap 28: 3/8 × 1 × 111/2  inch mild steel having a pair of 5/16 inch diameter holes each about 3/4 inch from an end of the strap; 
     rivet 42: 3/16 by 7/8 inch steel; 
     spring 44: 12 full turns over about 31/2  inches of what appears to be 1/16 inch diameter stainless steel wire; 
     cylinder 50: 13/4  inch diameter by 6 inch long black steel pipe, threaded on one end; having a 3/16 inch drain hole and having 5/16 inch by 11/8 inch notches for admitting handle ends 46; 
     cap 52: 13/4  inch black steel pipe cap having an 11/16 inch diameter hole bored in the center of the cap; 
     strike 54: 3/16 inch thick mild steel, by 11/16 inch I.D. and 11/2  inch O.D., 
     washer 56: 1/16 inch by 11/16 I.D. by 11/4  O.D. 
     sleeve 58: sheet steel 1/16 inch by 23/8  inch by 21/4  inch long rolled into a cylinder. 
     Bolt 14, yoke 20, plates 22 and 24, strap 28, cylinder 50, cap 52, and strike 54 were each selected of a material suitable for welding. Strike 54 was welded to bolt 14 about four inches from one end; this end was heated until malleable and then beveled by means of a hand sledge hammer. Yokes 20 were welded to cylinder 50 as was plate 22. Strap 28 was welded to cap 52. Catch 16 was formed and welded along its seam. The holes in handles 12 were drilled by a drill press after first locating the hole position with a hand punch. Assembly of latch 10 consists of inserting bolt 14 into cylinder 50 with the beveled end of the bolt extending through the aperture in plate 22. Spring 44, washer 56 and spacer sleeve 58 are each placed over bolt 14 and cap 52 screwed on to complete the assembly. Mounting of the latch 10 handle and casing assembly to a 16 foot, 2 inch diameter pipe gate was made by drilling a 5/16 inch hole in a horizontal member 34 and a pair of 5/16 inch holes in a vertical member 38. The latch 10 catch plate 16 attachment was facilitated by drilling a pair of 5/16 inch holes through a gate post 40. 
     FIG. 5 is an alternative embodiment of a latch 10. A handle 12 comprises a single continuous rod having a hook shaped end 62 which is a moveable member for engaging an eye 64. The second end 66 of handle 12 is configured to be normally in a recessed position extending from the front side 68 of gate post 40 and curling around behind post 40 to the vicinity of the post 40 back side 70. Access to the back side 70 by animals is prevented by related structure such as barbed wire 72. Handle 12 is mounted to gate post 40 by mounting plate 74, and is normally held in a position having end 66 recessed as described by bias means in the form of spring 76. Spring 76 is chosen according to the type of animal contained within the enclosure. Because application of a push of sufficient force to the gate operating through catch 64 would also operate handle 12, the embodiment of FIG. 5 is intended for applications such as baby pig farrowing pens or lamb pens in which the farm animals are insufficiently large to individually or in combination apply a sufficient pushing force to open the gate, or, alternatively, for sliding rather than swinging gates. 
     FIG. 6 illustrates an embodiment of a latch according to FIG. 1 which incorporates a lock mechanism shown generally as 80. The lock mechanism 80 comprises a strap 82 carrying an aperture 84 therein, bolt or rivet 86 for pivotally securing strap 82 to cap 52, an aperture 88 in attachment means 28, and a padlock 90. When locked the finger 92 of padlock 90 passes through apertures 84 and 88 to position strap 82 over the end 94 of bolt 14 to prevent rearward (withdrawal) movement of bolt 14. When unlocked, strap 82 pivots free and clear of end 94 as shown in phantom. 
     Having thus described how to make and use the invention by means of the foregoing illustrative embodiments, the former of which is the best mode contemplated by the inventor for carrying out his invention, variations and modifications to the invention as described and illustrated herein shall be obvious to a person skilled in the art. All such variations and modifications are deemed within the scope of the invention, the true scope of which is defined by the following claims.