Abstract:
A V type nail has two side portions, at least a part of each side portion being outwardly tapered from the driven end to the leading or cutting edge thereof so as to act on woodwork or other suitable material as it is driven therein at a joint and thus obtain and maintain a tight joint.

Description:
BACKGROUND OF THE INVENTION 
     1. FIELD OF THE INVENTION 
     This invention relates to V type nails or wedge fasteners as used for joining purposes especially, but not exclusively, for securing wooden frame members of picture or similar frames i.e. at mitre joints between the frame members. Various other uses of the nails arise generally in woodwork and joinery. 
     2. DESCRIPTION OF THE RELATED ART 
     As currently used and shown in FIGS. 1 and 2 of the accompanying drawings such V nails are made of thin sheet steel and provide two diverging sides portions  1  about an included angle of 90 degrees or thereabouts, the outer edges of the side portions being outwardly flanged in a curved manner at  11 . The side portions  1  at one end of the nail are sharpened to provide cutting edges to enable the nail to be driven into woodwork in the manner shown in FIG.  2 . 
     Hitherto the practice has been to provide at least two kinds of nail, one suitable for softwood and the other for hardwood. For softwood the single sided cutting edge is as shown in FIG.  3  and the double sided edge of FIG. 4 is for hardwood. In each case and as the nail is driven into abutting frame as like members F e.g. at a mitre joint M (FIG. 2) the action of the taper cutting edges T is to draw the frame members tightly together at the joint. In the case of the nail for hardwood use such drawing together action is augmented by controlled outward flaring or the opening deformation of the sides  1  of the nail. 
     As shown in FIG. 5, the nails may be provided in detachably adhered stick form  7  for convenient use such as by power driven hammer operation. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an improved dual purpose form of V nail capable of effective use in both softwood and hardwood. A further object is to enable the nails to be readily driven into position with especial advantage as regards power tool operation. These and other practical advantages will be apparent from the following description. 
     According to the invention a V type nail is characterised by at least part of each side portion of the nail being outwardly tapered from the driven end to the leading or cutting edge end thereof so as to act on woodwork or other suitable material as it is driven therein at a joint and thus obtain and maintain a tight joint. 
     The leading or cutting edge end is preferably sharpened to an unequal double sided edge configuration as for hardwood. 
     Tapered outer parts of the side portions of the nail may be about a lesser included angle than that between inner parts of the side portions at their V form junction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A practical example of V type nail according to this invention is shown in the further accompanying drawings in which: 
     FIG. 1 is a is a perspective view of a prior art nail. 
     FIG. 2 is an end view of the nail of FIG. 1 in a position of use. 
     FIG. 3 is a view of a cutting edge of the nail of FIG.  1 . 
     FIG. 4 is a view of an alternate cutting edge for the nail of FIG.  1 . 
     FIG. 5 is a plan view of a stick of the nails of FIG. 1 ready for use. 
     FIGS. 6 and 7 are respectively a leading cutting edge end view and a rear driven end view of the nail. 
     FIG. 8 is a side elevation. 
     FIG. 9 is a plan view of a stick of the nails ready for use. 
     FIG. 10 is an end view of the nail in position of use. 
     FIG. 11 is a plan view of a stick of the nails ready for use. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Like parts are referred to by the same or similar reference numerals throughout the drawings whilst any dimensions or angle values are given by way of example only and may be varied according to requirements. For clarity the drawings are generally shown on a somewhat enlarged scale since typically in practice the nail maybe of the order of 10 mm wide by 5 mm to 15 mm long, typically 5, 7, 8, 10, 12 or 15 mm long. 
     Referring to the drawings the nail is produced from thin sheet steel e.g. 0.3 mm thick and is formed to a general V form so as to provide two outwardly diverging side portions  10  from the V junction  12 . The outer edges of the side portions  10  are outwardly flanged at  11  in the usual manner. 
     For the purpose of this invention an outer part  13  of each side portion  10  is outwardly tapered from the rear or driving end  15  of the nail to the leading or cutting edge end  16 . In order to enable this to be achieved and the V junction retained, the outer parts  13  are mutually inclined about a lesser included angle (e.g. 60 degrees) than that of the inner parts  14  which latter provide the V junction  12 . The included angle in the case of the inner parts  14  maybe of the order of 120 degrees. 
     The profiles of the rear end and the leading end of the nails are ideally the same for the different lengths of nail with the offset  20  of the leading to the rear end being 0.3 mm. The result is a varying angle of taper from the rear end to the leading end as shown in Table I below. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                                               TABLE I 
               
               
                   
                   
               
               
                   
                 Nail length (mm) 
                 taper angle 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 5 
                 3.43° 
               
               
                   
                 7 
                 2.45° 
               
               
                   
                 8 
                 2.15° 
               
               
                   
                 10 
                 1.72° 
               
               
                   
                 12 
                 1.43° 
               
               
                   
                 15 
                 1.15° 
               
               
                   
                   
               
             
          
         
       
     
     The cutting edges T at the leading end are preferably of double sided edge form (as per FIG. 4) so as to be suitable for both softwood and especially hardwood. 
     As the nail is driven into position of use at a mitre joint M the mutual taper of the outer side parts  13  presses against the adjacent wood and thrusts the inclined ends of the frame members F firmly together at the mitre joint M so that a tight joint is obtained and maintained. 
     In the case of softwood little or no deformation of the nail occurs but as regards hardwood the much higher resistance of the latter against the cutting edges causes some opening out or flaring of the nail. However this is controlled or counteracted by the taper action to maintain a tight joint. 
     The angled formation of the side portions  10  and the tapering of the outer parts  13  is such that they lie slightly across the grain G of the frame members F which assists in obtaining a tight joint (see FIG.  10 ). 
     The form and arrangement of nail according to this invention also provides a further practical advantage where the nails are provided or collated in stick form  17  (FIG. 11) from which they are individually picked off and driven into position of use especially by a power tool such as a pneumatic hammer. 
     With conventional V nails as referred to above with reference to FIGS. 1 to  5  the collated nails  7  (FIG. 5) nestle together in intimate full face contact which presents a problem when picking off individual nails. This has been overcome by using a driving hammer head of corresponding but thinner form than the nail which means that only a hammer head of low strength can be employed. An alternative procedure has been to use a more robust hammer head but in order to allow for manufacturing tolerances and to avoid inadvertently catching the next nail in the stick  7 , only restricted engagement of the head with the driving end of the nail is possible e.g. of the order of 85% contact. 
     However the taper form of the side parts  13  of the nail in accordance with this invention results in the collated nails in a stick  17  being spaced apart by a gap  18  between the side parts  14 . This enables a hammer head of adequate strength and suitable profile to be employed so as to fully contact the driving end of the nail i.e. with as much as 100% contact engagement and without fouling an adjacent nail in the stick  17 . Indeed the hammer head may slightly extend beyond full contact with the nail end i.e. partially over the gap  18 . 
     As will be apparent from the foregoing the nail provides a number of significant practical advantages whilst various modifications maybe made to it within the scope of the invention herein defined.