COUNTER~FLOW SURGE

The problem

To tackle the problem of high injury rates in commercial cleaners, research was needed. An initial literature review was supported by qualitative research consisting of an online survey, an interview, and archival footage analysis. From this research, 4 main issues emerged that could be addressed:

“I have worked as a cleaner for a while now and know lots of people working as cleaners and struggling with pain from those backpack vacuums.”
Survey response

WRIST PAIN:
A number of factors correlated with wrist pain, but the most effective to target was the user’s wrist position. A neutral wrist position puts the least amount of strain on the muscles, tendons, and ligaments, reducing the chance for repetitive strain injuries. Existing vacuum handles force the user to constantly bend and straighten their wrist on the push and pull stroke of the vacuuming motion. If this could be eliminated, repetitive strain injuries should be minimised.

BACK AND SHOULDER PAIN:
The main factor in back and shoulder pain is the backpack harness. When wearing weight on the back, the best ergonomic outcomes come from positioning it as close to the user’s centre of gravity as possible, and distributing the weight onto the hips instead of the shoulders. Some vacuums on the market have some of these features, but most don’t adequately meet the support needs of users.

LOWER QUALITY MATERIALS:
Lower quality materials used in current vacuums wear out quickly and break, causing usability issues that affect proper ergonomics. Some examples include: cheap rollers on vacuum heads that break or fall off (leading to greater difficulty of movement), elastic hip straps that stretch over time (rendering them unusable and therefore placing all the vacuum weight on the shoulder straps), and cheap foam padding that quickly compresses and wears out (leading to discomfort, but also trapping of heat and sweat).

LACK OF MAINTENANCE:
An important influence identified in the research phase were employer factors, the most relevant being lack of maintenance. Employers are, predictably, motivated to spend as little as possible, leading to damaged equipment going years without repair or replacement, severely affecting not just the efficiency of the cleaning staff, but their health and well-being as well.

the solution

a total vacuuming package

The most appropriate solution was a complete vacuum redesign. As employers were averse to repair and replacement, they would be more likely to buy a better vacuum from the beginning than to purchase an ergonomic upgrade kit, for example. The interconnected nature of so many of the issues and ergonomic influencing factors also pointed towards a complete redesign.

Enter the COUNTER~FLOW SURGE…

the handle

free rotation or user-defined locking

The handle spins freely on an internal bearing, allowing the use to hang it by their side and simply swing their arm forward and backward. The user’s index finger can be used to hook on to the top of the handle if preferred.

By pushing the button on the handle forward, the TIDAL LOCK is engaged, locking the handle in a position of the user’s choice. This allows greater precision control for navigating around obstacles, easier lifting of a stuck vacuum head, or (if the user prefers) a more traditional vacuuming motion.

How the tidal lock works

An internal spring loaded hirth joint allows for free rotation around the axis when disengaged. When the button is pushed forwards (and clicks in with a ball detent), a wedge pushes the gear along the axis, engaging with the corresponding fixed gear and stopping rotational movement.

variable suction control

While vacuuming, the suction of the vacuum can vary based on factors such as dust bag fullness, the surface being vacuumed, or the condition of the rollers on the vacuum head. To help mitigate the extra strain produced by vacuuming with high suction, the SURGE has an air inlet valve that can be opened or closed to vary the amount of airflow, and thus the suction power.

Materials

Plastic components (injection moulded): ABS was chosen due to it’s relatively inexpensive high impact resistance and durability

Handle rubber (overmoulded): Shore 50A TPE was chosen for it’s good chemical compatibility with ABS. 50A allows for some comfort and deformation without introducing a “loss of control” feeling, which would result in an increase in grip force, and therefore strain.

Mechanism components (metal injection moulded): Stainless steel was chosen for it’s corrosion resistance and high tensile strength.

The harness

The harness design was inspired by hiking backpacks as they have a similar use case – distributing weight carried on the back while allowing for safe, unconstrained movement. The main benefit of a hiking backpack is the hip strap – a padded strap that hugs the waist/hips, allowing the bulk of the weight to be carried on the hips rather than the shoulders. The chest strap is another feature, with a small strap connecting the main shoulder straps and preventing side-to-side movement from twisting the torso.

To allow for size differences in users, the shoulder straps are connected with a keyhole mount, supported by hook and loop.

The SURGE boasts S straps (left), which contour better to the user’s body than J straps (right), causing less surface pressure on the skin of the shoulders. S straps also conform better to the bodies of people with breasts.

The hip strap on the SURGE has a pivot point that allows it to rotate, matching the natural walking gait of the user, while still providing support and taking the weight of the vacuum.

“Most of the time those hip belts are… elastic… [t]o be able to accommodate different sizes of waist or hips, and they are so worn that you can never use them after a while. If you use them, you will have to tie them in a knot and that will make it pretty uncomfortable if you have to take the backpack off”
Interviewee

materials

Padding:
-Dual density foam (Polyurethane foam around an EVA foam core) provides stability, as well as comfort and breathability
-Spacer mesh adds an extra air layer for maximum breathability

Covering:
-Durable canvas provides looks and longevity at the same time

Webbing:
-Nylon webbing for strength and longevity

Hardware:
-ABS buckles and sliders for their inexpensive toughness

the vacuum body

The main improvement in the vacuum body itself is the rear facing motor heat vent and extra internal insulation to prevent heat from radiating into the user’s body.

conclusion

The COUNTER~FLOW SURGE addresses shortcomings in backpack vacuums that lead to efficiency problems, wrist pain, shoulder pain, back pain and injuries. It’s innovative handle and tidal lock technology allows for a neutral wrist position or user choice, while it’s complete harness system supports and protects the user.

Joshua Law

The problem