Method of making keyboard switches

In a method of making a keyboard including a number of switch keys fixedly provided on one surface of a resilient plastic sheet and a number of moving contacts formed on the other surface of said resilient plastic sheet, the improvement wherein

• said switch keys are formed from a plastic material having a melting temperature lower than that of the resilient plastic sheet, and
• the method includes the steps of:
• (1) disposing a thermoplastic bond layer on at least one part of said resilient plastic sheet, the melting point of the thermoplastic bond layer being lower than that of the switch keys,
• (2) placing said resilient plastic sheet in a metal mold including cavities at predetermined positions to form said switch keys,
• (3) injecting melted plastic material into the mold cavities thereby forming said switch keys and at the same time causing the portions of said thermoplastic bond layer in contact with the injected melted plastic to be melted by the heat of the injected melted plastic material and to bond said switch keys onto said resilient plastic sheet.