×

Method and apparatus for welding a metal fastener to a metal member

  • US 6,624,379 B1
  • Filed: 04/15/2002
  • Issued: 09/23/2003
  • Est. Priority Date: 04/15/2002
  • Status: Expired due to Term
First Claim
Patent Images

1. A projection welding apparatus for welding a metal fastener to a metal member, the fastener including a plurality of protrusions, the apparatus comprising:

  • (a) a first electrical contact with a cavity for matingly fitting an outer perimeter of the fastener, the cavity being a least partially defined by an inner annular surface of the first contact;

    (b) an outer annular housing having a forward end portion, a rearward end portion and a central annular portion defining an internal opening extending internally along a length of the housing, wherein;

    i) the forward end portion supports a second electrical contact;

    ii) the internal opening includes a first chamber adjacent the forward portion and a second chamber adjacent the rearward portion and an elongated tunnel intermediate the first and second chambers; and

    iii) the forward end portion and the second contact cooperatively define a through-hole of the opening;

    (c) a piston assembly disposed within the opening of the housing, the piston assembly including a piston and a pin wherein;

    i) the piston includes a first forward end adjacent the forward end portion of the housing and a second rearward end adjacent the rearward end portion of the housing;

    ii) the pin includes an inner cylindrical steel core surrounded by an annular insulator, the insulator formed of a ceramic material, the insulator being thinner about the core at a free end of the pin for forming a shoulder thereon (d) at least one pressurized fluid source in fluid communication with said first and second chambers for translating the pin and piston assembly between an extended position, an intermediate position and a retracted position;

    (e) a first sensor adjacent to said first chamber and a second sensor adjacent to said second chamber, said first and second switches for monitoring whether the pin and piston assembly are in the extended position, the intermediate position or the retracted position;

    (f) an electrical energy source electrically connected to the first electrical contact and the second electrical contact for passing a current between the contacts and through the plurality of protrusions; and

    (g) a control unit in communication with the sensors, the electrical energy source and the fluid source for determining whether the pin and piston assembly have been successfully moved to the intermediate position for welding and for determining whether the pin and piston assembly have been successfully moved to the retracted position for removal of the fastener and member.

View all claims
  • 13 Assignments
Timeline View
Assignment View
    ×
    ×