Journal Critique: Humanscale Keyboard Tray
As the company’s name suggests, Humanscale designed this keyboard tray with ergonomics in mind. It can be intuitively be slid forward and backward, allowing the computer user to sit a comfortable distance from their screen without changing their normal arm positioning. It also has dark patches which clearly mark the available spots for both a keyboard and mouse, ensuring the user understands how to use it. There are, however, some major drawbacks that require a redesign.
Much of the tray’s intuitive design is undercut by the inability to vertically adjust the tray’s position. Given that the tray is placed under the table (about 4 to 6 inches below the table’s surface), there are many scenarios where the keyboard’s lower height will make using the tray uncomfortable. If the user has a chair with non-adjustable arm rests, their arms resting level will likely be too high, requiring the user to strain their arms to get to the keyboard. The short distance between the keyboard and bottom of the table may be an issue for those with large hands as their knuckles may strike the table’s underside when typing. If the user has long legs, their knees may not fit comfortably underneath the tray (which is currently an issue in a lab on the CIT’s 2nd floor). For those with long arms and torsos, keyboards may be more comfortable at positions above the table height, which is impossible for this design.
Some other issues with the tray are its size and angle-adjusting dial. The relatively thin tray depth leaves little room for the user’s wrists to rest. While the dial’s design allows angle for adjustment without tightening/loosening a gear (like the Sunlab trays), its positioning is its downfall. To angle the tray away from the arms, the user must reach to the back of the tray to rotate the dial. Since the tray moves up and down from the front (which is not intuitive since all keyboards move up/down in the back), the user may squish their wrist between the tray and table as the tray’s front moves upwards.
A few changes would help solve these issues: first, make the tray longer (in the axis toward/away from the user) to allow for more wrist room. Second, replace the table attachment (the part that had the dial) with a office-chair-style lever (except wider and under the left or right side of the tray) which adjusts the tray’s height. By doing so, the design avoids the aforementioned height issues. Third, move the dial to the front such that rotating it towards/away the display moves the backside down/up respectively. This makes the dial easier to reach and keeps the user’s hand out of the tray’s way as it moves.