Patent GB-767493-A (GB)
Title: Improvements in or relating to a nail making machine
IPC: B21G3/20
Filed: 1953-09-18
Abstract: 767,493. Forging nails. NATIONAL MACHINERY CO. Sept. 18, 1953 [Sept. 19, 1952], No. 25814/53. Class 83 (4). A wire nail-making machine has a header slide 17, Fig. 2, reciprocated in a horizontal direction by a crank-shaft 15, and a pair of nail cutters 27, 28, Fig. 9, pivoted to each other on fixed pins 33, 34, disposed respectively above and below the header slide and actuated by the latter through toggle linkages 43, 44, 45. Wire stock 11 on a reel 9 is drawn through a straightening mechanism 156 by a reciprocating feed mechanism 100, Fig. 5, and is passed through a spring-loaded guide quill 141, Fig. 2, to gripping jaws 73, 74, mounted in a support 77, which grip the wire whilst it is headed by a hammer 17a, mounted in the header slide, and then release it during the retraction of the header to permit a nail length to be advanced and then cut-off and pointed by the cutters 27, 28 which are closed by the toggle mechanism as the header slide reaches the end of its return stroke. The upper jaw 73 is fixed and the lower jaw 74 is reciprocated vertically by a pin 89 and a spring-loaded lever 84 driven by a cam 88 on the crank-shaft 15. Both gripping jaws may be adjusted in the vertical direction by screws 89, 94 and in the axial direction of the wire by a wedge 79, Fig. 6a (not shown). The hammer 17a may be adjusted axially by a wedge 197, Fig. 9. The cutters 27, 28 carry cutting and pointing knives 65 of tungsten carbide which are adjustable transversely of the wire and also vertically. Oil is supplied to the gripping jaws for lubricating the stock from a reservoir 215, Fig. 6 (not shown). The finished nails are ejected through a shoot 7, Fig. 1, and fall on to a conveyer 8. Sheet metal covers such as 183 prevent metal chips and scale from reaching the bearings and other close-fitting parts of the machine. Wire straightening.-The straightening mechanism consists of staggered rollers such as 157, Figs. 1, 5, of which one pair are mounted on a transversely movable slide 195 which is operated by a lever 161 to facilitate the insertion of the stock. Wireholding rollers 162 operated by a handle 165 are used to grip the wire during its insertion. Feed mechanism.-The reciprocating feed comprises a carriage 100, Fig. 5, carrying rollers 103, 104 running on a guide surface 146 and operated by toothed quadrant 133 engaging rack teeth in the carriage. The quadrant is mounted on a rocking shaft 124 driven from the crank-shaft through a chain 120, Fig. 16, and adjustable linkage 126-129, Fig. 4c (not shown), whereby the feed stroke of the carriage may be adjusted. The carriage has a quickfeed stroke and a relatively slow return stroke. A bar 106 pivoted at 105 to the carriage has a hardened steel block 107 which jams the wire against a second hardened steel block 108 on the carriage during the feed stroke. The bar 106 is pressed upwardly by a roller 109 mounted on a bell-crank 112 pivoted at 113 and biased by a spring 114. A cam 117 on a rotating shaft 123 releases the spring pressure and hence the grip on the wire during the return stroke. A manually-operated cam 154 is used to release the grip during adjustment of the mechanism. Ejectors.-The nails are ejected from the machine by a spring-loaded plunger 179, Fig. 16, mounted in a vertical tube 178 pivoted at 301 to an arm 177 mounted on a shaft 176 operated through linkage 175, 171, 166 by a cam 169 on the crank-shaft 15. A coil spring 181 mounted on a fixed bracket 304 has its free end engaged within the tube 178 to form with the arm 177 a parallel linkage whereby the tube 178 is alternately raised and lowered to eject the nail. Stop mechanism.-If the stock jams in the machine, the guide quill 141, Fig. 2, is moved against its spring and actuates a micro-switch 149, Fig. 10 (not shown), which stops the driving motor of the machine. Specifications 767,494, 767,495 and 767,496 are referred to.