Loose leaf binders

A loose leaf binder comprising:

• two substantially rigid covers hingeable with respect to a substantially semi-rigid outer curved spine along each of its two longitudinal edges,
• said outer curved spine being integrally formed with said covers,
• an inner rigid flat spine hingedly connected along each of its two longitudinal edges to said covers by means of welds extending substantially along hinge lines between said covers and said outer spine, and
• paper-retaining means for releasably retaining paper, said paper-retaining means being provided on said inner spine,
• wherein said inner spine comprises a strip of board enclosed in flexible weldable material, the width of the material being greater than that of the strip of board so that flexible hinge portions are produced along the two longitudinal edges of the strip,
• wherein the welds extending along the hinge lines unite respective ones of said hinge portions with the covers,
• wherein said outer spine includes a strip of semi-rigid weldable material enclosed in said flexible weldable material, and
• wherein each of the hinge-line welds unites the flexible material enclosing the covers, the strip of semi-rigid material and the flexible material enclosing the inner spine.

A loose leaf binder comprising:

• a semi-rigid curved outer spine having first and second side edges;
• two covers, each having a side edge;
• a first hingeable portion interconnecting said outer spine first side edge and a side edge of one of said covers;
• a second hingeable portion interconnecting said outer spine second side edge and a side edge of the other of said covers;
• said first and second hingeable portions having at least a part thereof formed of weldable material;
• a rigid, flat inner spine having first and second side edges;
• a third hingeable portion, at least a part thereof formed of weldable material, extending from said inner spine first side edge;
• a fourth hingeable portion, at least a part thereof formed of weldable material, extending from said inner spine second side edge;
• weld means for coupling said first hingeable portion to said third hingeable portion, and for coupling said second hingeable portion to said fourth hingeable portion;
• and
• paper-retaining means, coupled to said inner spine, for releasably retaining paper thereon,
• wherein said outer spine includes at least one sheet of flexible material and a sheet of semi-rigid material,
• wherein said outer spine sheet of semi-rigid material extends past said first and second hingeable portions.

A loose leaf binder comprising:

• a semi-rigid curved outer spind having first and second side edges;
• two covers, each having a side edge;
• a first hingeable portion interconnecting said outer spine first side edge and a side edge of one of said covers;
• a second hingeable portion interconnecting said outer spine second side edge and a side edge of the other of said covers;
• said first and second hingeable portions having at least a part thereof formed of weldable material;
• a rigid, flat inner spine having first and second side edges;
• a third hingeable portion, at least a part thereof formed of weldable material, extending from said inner spine first side edge;
• a fourth hingeable portion, at least a part thereof formed of weldable material, extending from said inner spine second side edge;
• weld means for coupling said first hingeable portion to said third hingeable portion, and for coupling said second hingeable portion to said fourth hingeable portion;
• and
• paper-retaining means, coupled to said inner spine, for releasably retaining paper thereon,
• wherein said covers and said outer spine comprise
• two four-sided boards having two sides adjacent and spaced apart,
• a semi-rigid weldable strip of material having opposite side edges, each side edge overlapping one of the adjacent sides of one of said boards,
• two sheets of flexible weldable material enclosing said boards and said strip, and
• weld means for coupling said two sheets and said strip together adjacent the peripheries of said boards.