Solution Summary: Two Handed Drills for Mixing
A two handed drill for mixing, such as the Rubimix-9, is an engineering control that may help reduce stressful hand and wrist activity. These drills have two handles that allow the user to securely and comfortably mix various viscous materials.
There are several types of two handed drills for mixing. Each provide a two handed grip for ease of use when mixing various materials such as concrete, thinset, mortar, grout, or other adhesives or coatings.
The Rubimix-9 series from RUBI Tools Inc. contains the Rubimix-9, Rubimix-9 PLUS, and the Rubimix-9 DUPLEX. These mixers weigh 12.1, 12.8, and 15 lbs respectively. Depending upon the model, the mixers are powered by a 11-14.5 Amp/110V motor. The Rubimix-9 and Rubimix-9 PLUS offer a 2-speed gearbox and electronic controller to optimize the mixing as well as interchangeable mixing paddles (Figure 1). The Rubimix-9 DUPLEX features dual mixing paddles that counter rotate to reduce torque (Figure 2).
Figure 1. The Rubimix-9 hand-held mixer.
Figure 2. The Rubimix-9 DUPLEX.
The Xo series of powered mixers from Collomix offer various models to meet different mixing needs. Each model offers a double action trigger with safety to prevent unintentional start-ups of the mixer. Depending on the model, the Xo series of mixers are powered by a 9 – 14.5 Amp/110V motor. The Xo 1 weighs 11.7 lbs and offers a single-gear motor with a speed of 0-650 rpm (Figure 3). The Xo 4 and Xo 6 offer a two-geared motor and weigh 13.7 lbs and 15.4 lbs respectively. The Xo 55 duo mixer is a counter-rotating, dual-paddle mixer (Figure 4). Xo 55 duo is powered by a 13 Amp/110V motor, has a single gear, and weighs 15.2 lbs. The Xo 55 was designed to reduce counter-torque on the operator while mixing various materials.
Figure 3. The Xo 1 hand-held mixer.
Figure 4. The Xo 55 dual-paddle hand-held mixer.
CS Unitec offers many types of two handed drills for mixing. They manufacture four models including the EHR 18 S, EHR 20 R, EHR 23/1.2 R, and EZR 22 R/RL. The EHR 18 S is powered by a 9.5 Amp/110 V AC motor and weighs 9 lbs (Figure 5). The EHR 20 R is powered by a 10.5 Amp/110 V AC motor and weighs 11.5 lbs. The EHR 23/1.3 R is powered by a 14.5 Amp/110 V AC motor and weighs 15 lbs. The EZR 22 R/RL is powered by a 10.5 Amp/110 V AC motor and weighs 15 lbs. The EZR 22 R/RL is a dual-paddle mixer with selectable clockwise and counterclockwise paddle rotation (Figure 6). The paddles rotate in opposite directions eliminating counter-torque for the operator.
Figure 5. The EHR 18 S hand-held mixer.
Figure 6. The EZR 22 R/RL dual-paddle hand-held mixer.
The 21665Q power mixer from QEP Inc. is powered by a 12 Amp/110V motor and weighs 13.5 lbs. It has a two-gear motor for various mixing speeds. RPM’s are controlled by a variable speed dial, enabling the operator to run the mixer at variable speeds, preventing splashing at startup (Figure 7).
Figure 7. The QEP 21660Q hand-held mixer.
Stressful hand and wrist activity and awkward wrist positions can cause musculoskeletal disorders (MSDs) such as muscle strains; tendonitis, which is inflammation of elbow and wrist tendons; or carpal tunnel syndrome, which is compression of a wrist nerve, resulting in finger numbness and loss of hand strength. A two handed drill for mixing can help reduce stressful hand & wrist activity because the two ergonomic handles reduces awkward wrist positions while mixing various materials in contrast to other hand tools used for mixing.
How Risks are Reduced:
A two handed drill for mixing minimizes stressful hand & wrist activity and awkward hand positions because two handles help to share the torque caused by the tool. These tools are moterized which allow workers to avoid hand-mixing materials. Some models also have dual-paddle mixing that reduces counter-torque when mixing.
Manufacturers of these drills believe there is reduced risk. RUBI Tools states, "[the Rubimix drill improves] ergonomics and comfort." Collomix states, "Optimum performance and perfect ergonomics. That's what the new Xo hand-held mixers are. Easy to operate with a straight back and ergonomically shaped grip handles." CS Unitec Inc. states, "[the EHR Series has] ergonomically designed metal frame and larger handles - robust construction and balanced grip ensure comfortable handling." Q.E.P Inc. states, "[the 21660Q Power Mixer has] ergonomic handle grips to reduce fatigue and minimize strain."
Safety and health experts believe the use of drills with two handles helps reduce torque applied to the hand and wrist while mixing materials, minimizing stressful hand & wrist activity and awkward wrist positions.
Effects on Productivity:
A two handed drill for mixing may increase productivity by reducing the amount of time it takes to mix various materials when compared to mixing by hand.
Some two handed drills for mixing may be heavier than other mixing power tools, which can impact user fatigue.
Dan Anton, PT, PhD, ATC; and Benjamin Tucker, SPT – Eastern Washington University
To obtain information, visit QEP 21665Q or contact 1-561-994-5550