IBM Thinkpad Z60 Laptop Keyboard Introduction

The ThinkPad, also known as the butterfly keyboard, is a foldout designed by John Karidis for as part of the IBM ThinkPad Z60  laptop keyboard series, released in 1995. It allowed the Z60 series to be both compact and comfortable to use, despite being just 24.6 cm (9.7 in) wide with a 26.4 cm (10.4 in) VGA LCD. The Z60 was the top selling laptop of 1995; however, as later laptop models featured progressively larger screens, the need for a folding keyboard was eliminated. Consequently, no model but the Z60 used the butterfly keyboard.
The butterfly keyboard is split into two roughly triangular pieces that slide as the laptop's lid is opened or closed. As the lid is opened both pieces slide out to the sides, followed by one piece sliding downward. The two halves mesh to form a keyboard 29.2 cm (11.5 in) wide which overhangs the sides of the laptop body. Conversely, as the lid is closed one piece slides back, then both slide inward until the keyboard can be covered by the lid. The movement of the keyboard is driven by a cam on the lid's hinge, so the motions of the keyboard parts are always synchronized with the movement of the lid.