Utah Arm

Since 1981, the Utah Arm has been the premier myoelectric arm for above elbow amputees. It was originally developed at the University of Utah by the Center for Engineering Design, led by Dr. Steve Jacobsen. In 1987, Motion Control released the Utah Arm 2, with entirely re-engineered electronics that made the Utah Arm the most durable and dependable myoelectric arm available.

The Utah Arm 3 – One Step Closer to Nature
In 2004, the Utah Arm 3 introduced microprocessor technology into the Arm, with a Computer Interface that allows the prosthetist or wearer to fine-tune the adjustments to achieve maximum performance. A variety of inputs may be used, so more options are available to more wearers. Meanwhile, the U3 still delivers the same sensitive, proportional control of elbow, hand and wrist (optional), letting the wearer move the arm and hand slowly or quickly in any position. This provides a more natural response with less effort than the traditional on/off movement.

What’s new about the U3?

  • Simultaneous Elbow and Hand control! Because the Utah Arm 3 has two microprocessors, two functions can be controlled at once (optionally), thus producing a more natural movement.
  • More Input Options
    • EMG Preamps using disc or snap-type electrodes
    • Motion Control Linear Potentiometer
    • Motion Control Touch Pads
    • Motion Control Force Sensor
    • Otto Bock Linear Transducer
  • Easy to Use Computer Interface For adjustments by the prosthetist The Set-Up Wizard guides you through the process of setting up your system step-by-step. Once set up, users can readjust by routing directly to the adjustment screens.
  • Maximum Function The Utah Arm 3’s mobility and fine tuning allow any patient to achieve maximum function, including transhumeral, forequarter amputees and shoulder disarticulation. Many arm wearers master function quickly, after training with a qualified Therapist.

The Utah Arm 3 Technical Specifications

  • Excursion Range: 135°
  • Excursion Time With Myoelectric Hand TD: 1.20 seconds
  • Active Lift: 1 kilogram (2.2 lbs.) in the Terminal Device and using a fully charged Battery
  • Load Limit: 22.7 kg (50 lbs.), w/ elbow locked at 90o flexion15.9 kg (35 lbs.), when forearm extension installed
  • Humeral Rotation: Unlimited
  • Wrist Rotation: Quick-Disconnect Wrist: 360° in each direction
  • Weight: Without Hand: 913 grams (2 lbs.)Hand Weight: 450 gm (1lb.), plus glove
  • Heat Tolerances: Operating Temperatures: 0° to 44°C (32° to 110°F)
  • Storage Temperatures: -18° to 60°C (0° to 140°F)
  • Current: Maximum: 4.0 Amps Quiescent: 10 mA
  • Battery Specifications: (5 Battery Packs supplied) Rechargeable NiMH, (1100 mA Hours capacity)
  • Voltage: Dual Supply, ± 6 Volts D.C. (total 12 V.)
  • Charge Time: 2.5 Hours, maximum
  • Forearm Length: (from rearmost point of the forearm to the end of the wrist)
    • Standard: 27.3 cm (10.75 in.)
    • w/Extension: 32.4 cm (12.75 in.)
    • Minimum: 24.8 cm (9.75 in.)

See also
Download Techniques for using snap-on electrodes with roll-on gel liners (PDF)
Download the U3 Quick Set Up Guide (includes parts catalog) (PDF)