Methods and assemblies for mounting parts

A method of mounting a section of a flat metal spring between a thermoplastic base frame and a thermoplastic locking insert, which comprises:

• (a) positioning the spring, on edge, in a rectangular, vertical mounting cavity formed in the frame so that a mounting section of the spring fits against a flat side wall of the cavity and an end portion of the spring extends from the cavity;
• (b) assembling the locking insert with the frame so that a flat top section of the insert fits against flat horizontal upper surfaces of the frame and so that a rectangular finger portion of the insert fits into the cavity so as to position the spring mounting section in close proximity between a flat outer surface of the finger portion and a flat wall portion of the cavity;
• and
• (c) ultrasonically heating the parts, while forcing them togehter so that energy director sections formed along portions of the under surface of the insert melt to weld the facing plastic parts together and further so that portions of the molten plastic flow inwardly along vertical slots formed in the outer surface of the finger portion so as to encapsulate portions of the spring between the finger portion and the cavity wall in the flowed plastic.

A kit of component parts capable of being assembled together for mounting a section of an elongated piece part between said component parts, which comprises the combination of:

• a base member having a cavity in which the mounting section of the piece part is adapted to be received;
• and
• an insert member having a mounting portion shaped to fit into the cavity so as to position the mounting section of the piece part between the mounting portion of the insert member and a wall of the cavity;
• at least one of the members having thermoplastic portions formed along a surface thereof adjacent to the other member and adapted to be melted, while simultaneously forcing the members together so as to weld the two members together;
• at least one of the members having a slot formed adjacent to the mounting section of the piece part between the members and arranged so that portions of the molten plastic flow into the slot when the thermoplastic portions are melted to encapsulate the mounting section of the piece part between the members in flowed plastic.

An assembly comprising:

• (a) a base member having a vertical cavity;
• (b) an elongated flat contact spring having a mounting section positioned on edge in the cavity against a flat vertical wall thereof and having an end portion extending outward from the cavity;
• and
• (c) a thermoplastic insert member welded to the base member and having a depending finger portion fitting in the cavity with a flat outer surface of the finger portion located in close proximity to the inner edge of the spring mounting section in the cavity so that the mounting section of the spring is sandwiched between the flat vertical wall of the cavity in the base member and the flat outer surface of the depending finger portion, the flat outer surface of the finger portion having at least one open-ended vertical slot facing the spring mounting section and filled with a sufficient volume of melted plastic to encapsulate the mounting section of the spring in the melted plastic so as to securely lock the mounting section of the spring between the insert member and the base member so that the end portion of the spring extends outward from the cavity.

A thermoplastic insert member having component parts capable of being assembled with a base member so as to mount a section of an elongated piece part between the members, which insert member comprises:

• a first portion having a flat working surface adapted to fit against a flat facing surface of the base member on assembly of the members;
• a mounting portion extending from the first portion and adapted to fit into a cavity in the base member when the members are assembled, with the mounting section of the piece part being positioned between the outer surface of the mounting portion and a wall of the cavity upon assembly, the mounting portion having at least one open ended slot formed in the outer surface thereof and positioned adjacent to the mounting section of the piece part on assembly;
• and
• a plurality of meltable thermoplastic elements formed along the flat working surface of the insert member adjacent to the flat facing surface of the base member and having portions positioned adjacent to an open end of each slot and arranged so that, when the members are assembled with the piece part, the insert member is adapted to be heated ultrasonically, while forcing the members together so that the thermoplastic elements melt and portions of the molten plastic flow into each slot to encapsulate the mounting section of the piece part between the members in flowed plastic, wherein the thermoplastic elements include a first set of pointed triangular energy directors running along the working surface of the insert member and occupying positions adjacent to an open end of each slot so that molten plastic from the first set of energy directors is adapted to be forced inward into an open end of each slot when the plastic is melted.