Method and apparatus for applying a corrosion-resistant coating to fasteners

Abstract

A method of applying a corrosion-resistant coating to a fastener that includes preheating an area of the fastener to be coated to elevate a temperature of the area and spraying the preheated area of the fastener with a molten or semi-molten metal. In one embodiment, a corrosion-resistant coating applicator includes a support structure, a rotatable slotted fastener conveyer supported by the support structure, a feeder configured to feed fasteners to the rotatable slotted fastener conveyer, a fastener aligner configured to make head portions of the fasteners aligned with each other, a heater configured to heat head portions of the fasteners as the fasteners are being conveyed by the slotted fastener conveyer, and a sprayer configured to apply a corrosion-resistant coating to the heated head portions of the fasteners being conveyed by the slotted fastener conveyer. The present disclosure also provides corrosion-resistant coated fasteners made using the coating methods and/or coating apparatus.

The invention is claimed as follows: 
     
         1 . A corrosion-resistant coating applicator comprising:
 (a) a support structure;   (b) a slotted fastener conveyer supported by the support structure;   (c) a feeder configured to feed fasteners to the slotted fastener conveyer;   (d) a fastener aligner configured to align head portions of the fasteners with one another;   (e) a heater configured to heat the head portions of the fasteners as the fasteners are being conveyed by the slotted fastener conveyer; and   (f) a spray assembly configured to apply corrosion-resistant metal coatings to the heated head portions of the fasteners being conveyed by the slotted fastener conveyer.   
     
     
         2 . The corrosion-resistant coating applicator of  claim 1 , wherein the slotted fastener conveyer includes:
 (a) a first slotted plate;   (b) a second slotted plate aligned with the first rotatable slotted plate;   (c) a based plate aligned with the first rotatable slotted plate;   (d) at least one magnet between the first slotted plate and the second slotted plate and configured to hold the fasteners to the slotted fastener conveyer;   (e) a hub, wherein the first slotted plate, the second slotted plate, and the based plate are connected to the hub; and   (f) a wedge non-rotatably connected to the hub between the first slotted plate and the second slotted plate, the wedge configured to remove the fasteners from the slotted fastener conveyer, and the magnets.   
     
     
         3 . The corrosion-resistant coating applicator of  claim 1 , wherein the first slotted plate and the second slotted plate define aligned equally spaced slots along their respective perimeters. 
     
     
         4 . The corrosion-resistant coating applicator of  claim 3 , wherein the slots are configured to each fit one of the fasteners. 
     
     
         5 . The corrosion-resistant coating applicator of  claim 1 , wherein the slotted fastener conveyer includes:
 (a) a first rotatable slotted plate;   (b) a second rotatable slotted plate aligned with the first rotatable slotted plate;   (c) a rotatable based plate aligned with the first rotatable slotted plate;   (d) at least one magnet between the first rotatable slotted plate and the second rotatable slotted plate and configured to hold the fasteners to the rotatable slotted fastener conveyer;   (e) a central hub, wherein the first rotatable slotted plate, the second rotatable slotted plate, and the rotatable based plate are rotatably connected to the central hub; and   (f) a wedge non-rotatably connected to the central hub between the first rotatable slotted plate and the rotatable second slotted plate, the wedge configured to remove the fasteners from the rotatable slotted fastener conveyer, and the magnets.   
     
     
         6 . The corrosion-resistant coating applicator of  claim 5  wherein the first rotatable slotted plate and the second rotatable slotted plate define aligned equally spaced slots around their respective perimeters. 
     
     
         7 . The corrosion-resistant coating applicator of  claim 6 , wherein the slots are configured to each fit one of the fasteners. 
     
     
         8 . The corrosion-resistant coating applicator of  claim 1 , wherein the heater includes an induction heater. 
     
     
         9 . The corrosion-resistant coating applicator of  claim 1 , wherein the heater includes an open-flame heater. 
     
     
         10 . The corrosion-resistant coating applicator of  claim 1 , wherein the sprayer is aligned with an axis of a shank portion of each of the fasteners. 
     
     
         11 . The corrosion-resistant coating applicator of  claim 1 , which includes a first blower configured to discard excess portions of the corrosion-resistant coating. 
     
     
         12 . The corrosion-resistant coating applicator of  claim 1 , which includes a second blower to clean the head portions of the fasteners before the fasteners are heated.