Autoscrubbers - understanding squeegee adjustment

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Autoscrubbers - understanding squeegee adjustment Powered By Docstoc

By Brian Clark
Article 1 in a series of 4
Brian has over 20 years experience in practical applications with commercial cleaning equipment. His
company, Janitech Australasia, provided ongoing regional support for Castle Rock Industries’ Windsor,
Prochem and Century 400 brands. He can be contacted on 0414 944615 or

The earliest automatic scrubbers appeared in the 1930’s. Then, as now, they were
designed to scrub and clean the floor, pick up the water and leave it clean and dry in one
action. Over 70 years, the basic design of scrubbing action and squeegees for solution
recovery has not changed. Manufacturers have increased the vacuum power and
introduced simpler squeegee systems but long, dirty streaks and mopping of wet floors
after auto scrubbers is a common sight in so may malls, factories and Stores. Poor
squeegee adjustment costs the industry hundreds of thousands of dollars each year in
extra labour, increased frequency of strip and seals and lost contracts through dirty or
yellowed floors.

Blade Science

Before we adjust the squeegee, we must understand its action.

There are 2 blades on a squeegee – the front blade and the rear blade. They must contact
the floor evenly along the length of the squeegee assembly to ensure a good seal to
maintain vacuum and maximise and concentrate the airflow.

The front blade allows solution on the floor to pass through channels or notches in the
blade into the squeegee tool while maintaining vacuum to provide lift. It has to provide a
seal but doesn’t wipe the floor and generally does not wear as quickly as the rear blade.

The rear blade is the wipe blade. It has a smooth, sharp edge to wipe the floor to a near
dry condition. The rear blade wears out much more quickly than the front blade and must
be in good condition to contain the cleaning solution.

Blades should be changed when worn, torn or of unequal length. Newer scrubber designs
have two or four sided blades and tool less blade change systems, allowing the operator
to change the blade. These features will save you money, provided the operator checks
the blades before every use and changes the wearing edge before it is worn more than
half the thickness of the blade.

Adjusting the Squeegee

Adjusting a squeegee assembly is a two part process. Firstly the squeegee must have the
correct pitch. In other words, it must sit level on the floor when in the working position
for the squeegee blade to have the same deflection at each tip as well as in the centre.
This is especially important on curved squeegee assemblies.
A curved squeegee with a slight pitch to the front will quickly wear out it’s wing tips and
the rear blade will lose contact with the floor in the centre of the tool. Uneven tip wear
and a water trail from the centre of the blade are symptomatic of too much forward pitch.
A curved squeegee with a backwards pitch will wear the blade out in the centre while
providing little or no pickup at the wing tips.

The second adjustment is the amount of deflection or down pressure on the squeegee
blade. Before adjusting the down pressure you must first adjust the pitch to ensure that
blade contact and deflection is equal across the width of the squeegee.

Step 1: Getting the squeegee level on the floor - How to Adjust the Pitch

Before you adjust the pitch carefully read the instruction manual for your machine and
locate the adjustment devices for your machine.
1.   Check the wear edge of the rear blade. Change or rotate the blade if the blade is damaged or is less
     than half the original thickness. Change or rotate the front blade if it is torn or has an uneven edge.

2.   Choose a smooth level surface. Turn on the power switch and lower the squeegee to the working
     position. Release the parking brake (if fitted) and drive slowly forward approximately 60 cm.

3.   With the squeegee down, stop the machine by turning off the power and set the parking brake. Do not
     allow the machine to roll back.

4.   Now look at the rear squeegee blade. There should be equal deflection of the rear blade across the
     entire width of the squeegee. If the rear blade barely touches the floor then there is probably too much
     pitch to the front. If the blade shows a lot of deflection in the middle it means that the pitch is too far
     back and needs to be adjusted forward.

5.   Turn the machine on again and repeat steps 2 through to 4 until equal deflection is obtained.

Step 2: Adjusting the down Pressure – getting the correct amount of deflection.

This is where many machine operators come unstuck as they use the down pressure adjustment to cure all
faults. Too much down pressure forces the sides of the blades rather than the edge of the blade against the
floor surface. A blade with too much down pressure will smear the floor instead of wiping it dry and the
blades will quickly wear paper thin.
A blade with too little deflection will leave chatter marks on the floor.

Having adjusted the pitch and achieved equal blade contact you now need to adjust the downwards pressure
on the squeegee. The aim is to achieve a rear blade deflection of approximately 10mm (3/8 inch).

6.   On the same smooth level surface drive slowly forward approximately 60 cm.

7.   With the squeegee down, stop the machine, turn off the power and set the parking brake. Do not allow
     the machine to roll back.

8.   Observe the amount of blade deflection. It should deflect 10-12 mm across the entire width of the
     squeegee. (Refer Figure 1) If the deflection is less than the desired amount increase the down pressure.
     If the deflection is more than the desired amount, decrease the squeegee down pressure.

9.   Turn the machine on again and repeat steps 6 through to 8 until correct deflection is obtained.

10. Test run the machine observing water pickup patterns over a suitable area of floor. Make further
    adjustments if necessary.
Corrosion is the enemy of all squeegee systems. They operate in a constantly wet
environment. The detergent in the water, plus the dissolved and suspended soil,
breakdown and contaminate greases and metal threads quickly seize in Aluminium
housings. Ensure that all pivot points, screw threads and moving parts on the squeegee
system are regularly lubricated with a suitable water- resistant lubricant.

In part 2 of this series, we will continue our look at autoscrubber water pickup
performance. with a step by step walk through of the vacuum system. This is only a
guide. Remember the adage, if all else fails read the instructions first!

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Description: A series of 4 articles on achieving the best results from Autoscrubbers. They cover squeegee adjustment, vacuum systems, battery maintenance and troubleshooting
About Brian Clark has over 25 years experience in the commercial cleaning, janitorial Supply industry and as a commercial clenaing consultant. He specialises in setting specifications, key performance criteria and peformance management of cleaning and Facility Management Contracts. He is also a well known contributor to industry journals in Australia, USA and Europe.