The Adjustable Standing Desk for a Shared Office
A furniture manufacturer is designing a height-adjustable standing desk for a shared office of 60 workers aged 19 to 64, including two workers who use wheelchairs and one with a chronic lower-back condition. The desk must adjust from 620 mm to 1,280 mm, support 80 kg, and be operated by a single person. Early prototypes use a hand-crank mechanism with a 40:1 gear ratio requiring 22 turns to raise the desk 100 mm. User trials report that workers with limited grip strength cannot operate the crank, and the lowest height of 620 mm does not allow wheelchair armrests to clear the desktop edge. The desk is also reported to wobble at full extension when a user leans on it.
1. Analyse how well the prototype meets the needs of the specified user group, using the design factors of function, user needs and safety.
Read the worked answer
Function: the 620-1,280 mm range broadly suits standing and seated work, but the 22-turn crank to raise 100 mm means a full 660 mm adjustment needs about 145 turns, which is impractical for frequent changes and effectively discourages standing. User needs: the crank fails the two wheelchair users and the worker with a chronic back condition, because grip strength and repetitive wrist motion are barriers; a single-person operation requirement is not met for them. The 620 mm minimum height conflicts with wheelchair armrest clearance, so the desk cannot be used as an accessible workstation as specified. Safety: wobble at full extension indicates insufficient column stiffness or a poor locking mechanism, creating a tipping and pinch risk, particularly for a user transferring from a wheelchair. The design meets the general population but systematically excludes the users the brief explicitly names, which is a failure of inclusive design rather than an edge case.
2. Propose design changes and a testing plan that would resolve the identified problems before production.
Read the worked answer
Replace the hand crank with a dual-motor electric actuator with memory presets and a low-force control, or offer a crank as a backup only, so operation requires minimal grip strength and a single action. Lower the minimum height to about 580 mm or design a recessed front edge and tapered frame so wheelchair armrests clear the desktop. Increase column stiffness by using a three-stage telescoping column with tighter tolerances and a cross-brace, and specify a locking mechanism that engages at every height, not only at the top. Testing plan: recruit at least 10 users spanning the stated age and ability range, including both wheelchair users, and measure adjustment force, time to change height, armrest clearance, and lateral deflection under a 50 kg lean load at full extension. Run a 20,000-cycle durability test on the actuator and a stability test to the relevant furniture standard. Only release to production when all accessibility and stability criteria pass with the actual user group.