An alternative device to the traditional fixed-handle squeegee is a new device which the manufacturer calls the Wagtail cleaning tool. This device, illustrated in the accompanying photographs, incorporates several novel features, each of which has ergonomic implications for the execution of the window-cleaning task:
The 400mm wide cleaning head is free to rotate in relation to the handle of the device. Specifically, the axis of the handle lies at 37â to the plane in which the cleaning head rotates. This means that, when the cleaning head is placed on the window with the rubber squeegee blade at the correct angle to the window – ie with the handle at 20â to the glass – a 90â turning movement of the handle results in a 90â rotation of the cleaning head on the window.
The main ergonomic implication of the rotating head is illustrated in Figure 2. At the start of the cleaning movement (Position 1) the wrist is almost exactly in the neutral position. As the cleaning head is moved across the window through Position 2 to Position 3, a slight rotation of the handle, achieved by a lowering of the elbow and a supination of the forearm, rotates the cleaning head. At Position 4, with the forearm supinated, the wrist is still largely in the same neutral position it occupied in Position 1 (where the forearm was pronated).
Figure 2. The movement of a Wagtail device across the top of a window using the “S” motion. The handle is typically turned no more than 90â each way every cycle, accompanied by a 90â rotation each way. With a slight alteration in technique, the same action is achievable using the Wagtail device on a pole.