ERGONOMIC REPORT
INTRODUCTION
The occupation of window cleaner is one which involves the day-long manual manipulation of a device using a variety of awkward and often injurious postures and movements. Although little has been recorded in the literature concerning occupational overuse syndrome in window cleaners, anecdotal evidence from window cleaners, as well as the occasional article in trade publications (Reference 1) indicates that such trauma is common. The present report analyses these movements as carried out using traditional window-cleaning equipment and as carried out using a new window-cleaning device, the Wagtail , which incorporates two novel features- a pivoting handle and the combination of mop and squeegee. The effect of these innovations is to reduce significantly window-cleaning movements and forces which have the potential to cause occupational overuse syndrome.
The cleaning operation is as follows:
1.The mop is dipped in the water and the soapy water is applied to the window. Where shop windows are cleaned regularly the soil present is usually only a thin layer of dust, together with minor streaks and oily finger marks, all of which can be removed without any deliberate scrubbing action. The passing of the mop over the surface of the window with sufficient pressure to apply an even layer of water is all that is normally required.
2 .The mop is then exchanged for the squeegee. A common action would be for the operator to put the mop into the bucket of water and take the squeegee from a belt holder where it would be kept when not in use.
3. The window is dried with the squeegee. An experienced operator uses an “S” action. Typically, for a right-handed operator the squeegee begins in the top left corner with the blade slightly past vertical, with the handle pointing slightly upwards. It is moved horizontally across the width of the window, remaining approximately vertical until it is one squeegee width from the right-hand edge. At this point the top edge of the squeegee is moved faster that the bottom edge so that the squeegee turns through 180â as its direction is reversed. As shown in Figure 1, the movement from Position 1 to 4 involves a 180â turn of the squeegee handle. At this point the squeegee is moving horizontally across the window in the other direction, but one squeegee width lower down the window. The complete action is illustrated in Figure 1.
MOP AND SQUEEGEE COMBINED
A mop is incorporated in the cleaning head and is fixed immediately proximal to the rubber squeegee blade. Thus, in use, water is applied and is immediately squeegeed off with a single pass of the cleaning head over the window. The mop is a piece of carpet-like material fixed to a flat section 375mm long (ie slightly shorter than the rubber blade) and 35mm wide, cut away at a 45â angle at the ends to allow the squeegee to reach into corners easily. The mop is fixed to a flat plane positioned on the cleaning head so that when the mop surface is flat on the window the squeegee blade, resting in front of the mop, is automatically offered to the window at the correct angle of 55â. The depth of the mop surface is such that it is easy to maintain the mop surface flat on the window and therefore easy to maintain the squeegee at the correct angle with a minimum of wrist tension.