Method of ultrasonic welding and apparatus therefor

Means for spot welding sheet material comprising:

• ultrasonic energy application means for providing ultrasonic vibrational energy to heat said material;
• plate means having a planar face with projections extending therefrom for concentrating said ultrasonic vibrational energy at at least a desired spot to be welded;
• means for placing said ultrasonic application means and said means for concentrating into contact with said sheet material along a seam to be welded and for maintaining said contact until welding is completed;
• and
• reservoir means adjacent said spots but spaced therefrom for receiving material displaced from juxtaposition with said means for concentrating to thereby strengthen the resulting welds, said reservoir means being recessed below the planar face of said plate means.

Means for spot welding sheet material comprising:

• means for supporting first and second sheets in juxtaposition along a desired weld line;
• ultrasonic generator means for producing ultrasonic energy;
• ultrasonic transducer means located on a first side of said sheet material for transmitting ultrasonic energy to said sheet material along side weld line;
• plate means having planar face with projection extending therefrom for concentrating said ultrasonic vibrational energy at desired spots to be welded along said weld line;
• anvil means for supporting said plate means for concentrating on a second side of said weld line;
• means for placing said ultrasonic transducer means and said plate means for concentrating into contact with said sheet material along said weld line and for maintaining said contact until welding is completed;
• and
• reservoir means recessed in said plate means and spaced from said projections, said reservoir means receiving material displaced from juxtaposition with said means for concentrating to thereby strengthen the resulting welds.

A method of spot welding sheet material comprising:

• ultrasonically applying vibrational energy to said sheet material to heat said material;
• concentrating said vibrational energy at spots desired to be welded by applying said ultrasonic energy through projections extending from the planar surface of a plate;
• and
• providing reservoirs spaced from but adjacent said spots for facilitating displacement of molten material produced by said heating process to strengthen the resulting welds, said reservoirs being recessed in the planar surface of said plate.