Patent No.:   US 4,913,772                                     Date of Patent: April 3, 1990

This invention relates to portable machines for welding together individual thermoplastic sheets in situ.  The machine heats different ...

Patent No.:   US 5,635,014                                     Date of Patent:  July 3, 1997

Press-type apparatus for thermally bonding thermoplastic sheet material workpieces is provided with a pair of opposed platen assemblies ...

Patent No.:   US 6,588,710                                      Date of Patent: July 8, 2003

Patent No.: Canadian 2,480,013                              Date of Patent: April 19, 2011   

This invention relates generally to railroad ...