Fujitsu FKB74xx and FKB76xx
Contents
Overview
FKB74xx and FKB76xx contain Fujitsu’s compact, notebook and handheld keyboards that use their “gear-link membrane” (ギアリンク・メンブレン方式, also ギヤリンク with ヤ “ya” instead of ア “a”) mechanism. The “gear link” mechanism serves the same purpose as the scissor arrangement in other brands’ keyboards. The design varies somewhat by series; the FKB7400 version is depicted below:
This general principle is discussed in a number of patents; the relevant patents discovered thus far are listed below, and may not all relate to these specific series:
| Company | Patent | Title | Priority | Notes |
|---|---|---|---|---|
| Nagano Fujitsu Component Ltd | US 5874696 A | Key switch, keyboard and portable information processing unit with keyboard | 1996-08-12 | Non-cross |
| Fujitsu Ltd | JP H11185564 A | Key switch, keyboard and information processor using these | 1997-12-22 | Non-cross |
| Fujitsu Ltd, Nagano Fujitsu Component Ltd | US 6257782 B1 | Key switch with sliding mechanism and keyboard | 1998-06-18 | Suggested to be spring-over-membrane |
| Fujitsu Component Ltd | US 7138587 B2 | Key switch, keyboard and key-switch assembling jig | 2004-07-01 | Non-cross |
| Fujitsu Component Ltd | US 8624140 B2 | Key switch and keyboard | 2006-07-10 | Non-cross |
The FKB7400 Series and FKB7610 Series datasheets both indicate that N-key rollover is possible with their “resistance matrix method”:
Nキーロールオーバーの対応当社独自の抵抗マトリクス方式により，メンブレンキーボードながらNキーロールオーバーを実現できます。
Specifications
Height, where given, refers to the internal assembly, and not to enclosed keyboards.
| Characteristic | FKB7400 | FKB7401 | FKB7412 | FKB7610 | FKB7614 | FKB7628 | FKB7660 | FKB7681 |
|---|---|---|---|---|---|---|---|---|
| Type | Custom | Standard | Standard | Custom | Standard | Standard | Custom | Standard |
| Height | 8.5 mm | 5.9 mm | 6.1 mm | 4.5 mm/5.0 mm | 5 mm | |||
| Keys | 83/84/87 | 83/87 | 87/88/92 | 87 | 64 | |||
| Travel | 3.0 mm | 3.0±0.5 mm | 3.0 mm | 3.0 mm | 3.0±0.5 mm | 3.0 mm | 1.5 mm/2.0 mm | 1.5±0.2 mm |
| Pitch | 19 mm | 19.05 mm | 19 mm | 19.05 mm | 12.8 mm | |||
| Op. force | 49 cN | 50±25 gf | 49 cN | 49 cN | 50±25 gf | 54 cN | 44 cN | 50±25 gf |
| Tactile drop | 20 gf | 20 gf | 20 gf | 20 gf | ||||
| Lifetime | 10 M | 5 M | 10 M | 10 M | 5 M | 2 M | ||
Series
FKB7400
FKB7400 Series appears to be for custom keyboards, with standard models appearing in FKB7401 Series.
FKB7401
FKB7401 series contains 83, 84 and 87 key notebook keyboards.
| Model | Keys | Layout |
|---|---|---|
| FKB7401-001 | 83 | United States |
| FKB7401-002 | 84 | United Kingdom |
| FKB7401-003 | Germany | |
| FKB7401-004 | France | |
| FKB7401-005 | Italy | |
| FKB7401-006 | Spain | |
| FKB7401-007 | Sweden | |
| FKB7401-008 | Switzerland | |
| FKB7401-051 | 87 | Japan |
FKB7412
FKB7412 is a 19″ rack keyboard similar to Cherry G84-4400, with an integrated trackball.
| Model | Layout | Keys | Connector |
|---|---|---|---|
| FKB7412-251 | Japan | 87 | USB |
| FKB7412-451 | PS/2 | ||
| FKB7412-201 | United States | 83 | USB |
| FKB7412-401 | PS/2 |
FKB7610
FKB7610 contains slim notebook keyboards. FKB7610 Series appears to be for custom keyboards.
FKB7614
FKB7614 contains 87, 88 and 92 key notebook keyboards.
| Model | Keys | Layout |
|---|---|---|
| FKB7614-101 | 87 key | United States |
| FKB7614-102 | 88 key | United Kingdom |
| FKB7614-103 | Germany | |
| FKB7614-104 | France | |
| FKB7614-105 | Italy | |
| FKB7614-106 | Spain | |
| FKB7614-107 | Sweden | |
| FKB7614-108 | Switzerland | |
| FKB7614-161 | 92 | Japan |
FKB7628
FKB7628 Series contains compact (75%) keyboards. This includes model FKB7628-801.
FKB7660
FKB7660 Series appears to be for custom types only, targeted at miniature notebooks and PDAs.
Documentation
The following documents are all archived from the current Fujitsu website, or from the Wayback Machine or similar. See the Fujitsu keyboards page for official copies where available.