Headrest guide-tube with interlacing

Abstract

Guide-tubes for supporting the headrest of an automobile seat are lock-beaded into the top-rail of the seat-frame. The guide-tubes are formed from pieces of sheet metal, folded over to form cylindrical tubes. The edges of the sheet are interlaced, by means of dovetailing tabs and sockets, which are stamped into the side-edges of the sheet. The interlacing tabs and sockets are not present over the middle portion of the guide-tube, where the lock-beads are formed.

1 . Headrest guide-tube for an automobile seat, wherein: 
 the tube has walls, which comprise a single sheet of metal, having left and right side-edges;    the walls comprise the sheet metal in a bent-over condition, in which the sheet has the configuration of a cylindrical tube;    the left and right side-edges of the sheet include respective upper-, middle-, and lower-, portions;    the upper-portion of the left side-edge carries a series of tabs and sockets, and the upper-portion of the right side-edge carries a corresponding series of sockets and tabs;    the bent-over tube is of a configuration in which the series of tabs and sockets carried on the upper-portion of the left side-edge lie interlaced with the series of sockets and tabs carried on the upper-portion of the right side-edge, thereby defining an interlaced upper-portion of the tube;    the middle-portions of the left and right side-edges of the sheet are plain and substantially free of tabs and sockets, whereby, in the bent-over configuration of the tube, the middle-portions of the side-edges are not interlaced, thereby defining a non-interlaced middle-portion of the tube;    the tube includes a first ring-bead, in which the sheet metal wall of the tube lies buckled radially outwards;    and the first ring-bead lies in the non-interlaced middle-portion of the tube.    
     
     
         2 . Guide-tube of  claim 1 , wherein: 
 the lower-portion of the left side-edge carries a series of tabs and sockets, and the lower-portion of the right side-edge carries a corresponding series of sockets and tabs;    the bent-over tube is of a configuration in which the series of tabs and sockets carried on the lower-portion of the left side-edge lie interlaced with the series of sockets and tabs carried on the lower-portion of the right side-edge, thereby defining an interlaced lower-portion of the tube.    
     
     
         3 . Guide-tube of  claim 1 , in combination with a seat-frame having a top-rail, wherein: 
 the tube passes through a through-hole in the top-rail, and the first ring-bead lies in contact with one side of the top-rail;    the tube includes a second ring-bead, in which the sheet metal wall of the tube lies buckled radially outwards;    the second ring-bead also lies in the non-interlaced middle-portion of the tube;    the second ring-bead lies on the opposite side of the top-rail from the first ring-bead, and the top-rail lies gripped between the first and second ring-beads.    
     
     
         4 . Procedure for manufacturing a headrest guide-tube for an automobile seat, including: 
 providing a piece of sheet metal, having left and right side-edges;    providing, along an upper-portion of the left side-edge of the piece of sheet metal, a series of tabs and sockets;    providing, along an upper-portion of the right side-edge, a corresponding series of sockets and tabs;    the series of tabs and sockets on the left side-edge corresponds to the series of sockets and tabs on the right side-edge in that, when the side-edges are brought together, the upper-portions of the left and right side-edges become interlaced together;    providing, along a middle-portion of the left side-edge, a left plain-edge, free of tabs and sockets;    providing, along a middle-portion of the right side-edge, a corresponding right plain-edge, free of tabs and sockets;    bending the piece of sheet metal into the form of a cylindrical tube;    the tube, thus formed, includes an upper-portion of the tube in which the upper-portions of the side-edges are interlaced together, and includes a middle-portion of the tube in which the middle-portions of the side-edges are not interlaced together;    placing the tube between dies;    the dies include a middle-portion of the dies, and the middle-portion of the dies is formed with a recess, into which the metal of the tube can expand radially outwards;    the recess is so positioned that only metal from the middle-portion of the tube, in which the edges are not interlaced, can enter the recess;    compressing the cylindrical tube axially with enough force to cause the metal of the tube to buckle axially, and expand outwards radially, into the recess, thereby forming a first ring-bead in the middle-portion of the tube.    
     
     
         5 . Procedure of  claim 4 , wherein the dies include an upper-portion of the dies, which is so arranged as to confine the said interlaced upper-portion of the tube against radially-outward expansion during axial compression of the tube.  
     
     
         6 . Procedure of  claim 5 , wherein the upper-portion of the dies is smaller, diametrally, than the interlaced upper-portion of the tube, whereby compressing the tube axially between the dies is effective to swage the upper-portion of the tube.  
     
     
         7 . Procedure of  claim 4 , including: 
 providing, along a lower-portion of the left side-edge of the piece of sheet metal, a lower series of tabs and sockets;    providing, along a lower-portion of the right side-edge, a corresponding lower series of sockets and tabs;    the lower series of tabs and sockets on the left side-edge corresponds to the lower series of sockets and tabs on the right side-edge in that, when the side-edges are brought together, the lower-portions of the left and right side-edges become interlaced together;    the tube, thus formed, includes a lower-portion of the tube in which the lower-portions of the side-edges are interlaced together.    
     
     
         8 . Procedure of  claim 7 , wherein the dies include a lower-portion of the dies, which is so arranged as to confine the said interlaced lower-portion of the tube against radially-outward expansion during axial compression of the tube.  
     
     
         9 . Procedure of  claim 7 , wherein the lower-portion of the dies is smaller, diametrally, than the interlaced lower-portion of the tube, whereby compressing the tube axially between the dies is effective to swage the lower-portion of the tube.  
     
     
         10 . Procedure of  claim 4 , including: 
 placing the tube in a through-hole in a top-rail of a seat-frame, with the first ring-bead abutting against the top-rail, and against the edges of the hole therein;    placing the top-rail and the tube, together, between dies, where the dies include a second recess into which the wall of the tube can expand outwards upon being compressed axially;    the second recess in the dies is so positioned that only metal from the middle-portion of the tube, in which the edges are not interlaced, can enter the second recess;    the second recess is positioned on the opposite side of the top-rail from the first ring-bead;    compressing the tube axially with enough force to cause the metal of the tube to buckle axially, and expand outwards radially, into the second recess, thereby forming a second ring-bead in the middle-portion of the tube;    whereby the top-rail is left gripped between the first and second ring-beads.    
     
     
         11 . Procedure of  claim 4 , wherein the sheet has a top edge, and the procedure includes forming a slot in the top edge prior to bending the piece of sheet metal into the form of the cylindrical tube.  
     
     
         12 . Procedure of  claim 11 , including forming chamfers at the entrance, in the top edge, into the slot.