Browsing by Author "Sears, Harold H."

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    Electric Wrist Rotation In Proportional-Controlled Systems
    (1995) Sears, Harold H.; Shaperman, Julie
    Electric wrist rotation has been available with electric hands for approximately 20 years. Although it is integrated with the Otto Bock electric hand, via their quick-disconnected wrist component, the electric wrist has been used in only a fraction of electric prostheses because of four perceived problems: 1) the additional length required in he forearm, which could eliminate mid-to-long transradial amputees as candidates, 2) the additional weight of the component, although only about 100 gm, 3) the speculation of most prescribing MD's and prosthetists that the function of electric writs rotation is unnecessary and unused by amputees, and 4) the difficulty of using the tiaditional wrist control methods. The introduction in 1989 of a proportional controller, which allows a simple switching method using muscles cocontraction, possibly makes an impact on problems #3 and #4 above. The control method is speculated to be easier to learn and to use, and also allows proportional control of the wrist rotation Powered by a 9 volt battery, or 12 volt in above-elbow applications, greater speed of wrists rotation is also provided. The purpose of this survey is to evaluate the actual usage of electiic wrist by the wearers of proportional systems, and to document the functions in which electric wrist rotation has proved valuable, if any. Also, the stuvey hopes to provide indications of the present drawbacks which remain, and provide direction for future improvements. The results to-date of the survey will be presented, and any conclusions which are warranted by the data. Future developments which could impact upon electric prosthesis usage will also be discussed. FULL PAPER UNAVAILABLE AT THIS TIME.
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    EVALUATION OF A NEW FLEXION WRIST INTEGRATED WITH ELECTRIC HAND
    (2002) Sears, Harold H.; Iversen, Edwin K.; Archer, Shawn
    A new electric hand has been developed which integrates flexion/extension into an electric hand, with no increase in length over standard-length electric or body-powered hands. The development* has included a field trial with six wearers of the electric hand. All the wearers were surveyed on the actual tasks they performed with the hand, including those utilizing flexion/extension. Electric Hands have typically operated with a single gripping mode, usually three-finger tip prehension. Our attempt at this stage is to enhance function in the hand, but without adding complexity to the gripping mechanism. Passive and electric wrist rotation can add an important degree of freedom (DOF), but still provides only one of the natural wrist’s three DOF. Additional degrees of freedom in the hand, however, would offer the amputee broader function of course, but practicality dictates the addition of a DOF without adding to the complexity of the hand.
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    EVALUATION STUDIES OF NEW ELECTRIC TERMINAL DEVICES
    (2005) Sears, Harold H.; Iversen, Edwin; Archer, Shawn; Linder, James; MacDonald, Joanna R.
    Two new electric terminal devices (TDs) have been developed for use with myoelectric prostheses of the upper limb, at all levels. They each feature a quick disconnect wrist connection, so they may be interchanged with each other, and also with existing electric TDs from other manufacturers
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    Evolution of the Utah Arm to Improve User Function
    (2008) Sears, Harold H.; Iversen, Edwin; Archer, Shawn; Jacobs, Tony
    An ambitious re-development of the Utah Arm was guided by direct clinical feedback, producing a list of features to improve the full-electric prostheses. The goals of the development focused on the following: • Smoother transition from elbow motion to hand function, and vice versa, i.e., more effortless locking and unlocking by the wearer, with many more locking positions. • Quieter operation of the elbow, both during the locking and unlocking operations (which can produce an audible “click” of the lock pin}, and during the powered freeswing function, which produces audible motor and gear noise. • More convenient connection of the prosthesis to the prosthetist’s or therapist’s computer for adjustment and training, which required a hard-wired connection of cables. • Wider range of input devices, as well as TDs, to take advantage of all available input sensors and output devices. Rather than “start over”, the technical capabilities and approach of the existing Utah Arm fullelectric system were used as a starting point, giving more advantages than disadvantages. Development time is greatly shortened by taking the approach of modifying an existing component, without the risks of using unproven designs. It is important to realize as well – the product is intended for clinical, rather than laboratory use, so practicality is of a very high priority.
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    Utah Arm 2: New Technologies Applied To Electric Elbow And Hand Systems
    (1997) Sears, Harold H.; Iversen, Edwin; Dyck, Arthur D.; Hays, Kevin; Rivera, Caesar
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    Wrist Innovations To Improve Function of Electric Terminal Devices
    (2008) Sears, Harold H.; Iversen, Edwin; Archer, Shawn; Jacobs, Tony
    A major challenge in the development of terminal device (TD) and UE prosthetic devices is to add to the functional benefits to the wearer, without greatly increasing the weight, or complexity, or the cost of the prosthesis. Using existing TD designs, the opportunity existed to increase the function by increasing the degree of freedom available at the wrist, in several ways. Since the existing hands and electric terminal devices (ETD) were both single degree-of-freedom TDs, improving the positionability of the TD can logically improve the gripping orientation and grip security. Our goal was therefore, to improve positionability of TDs via improved wrist flexion/extension devices, and an improved wrist rotation device, which could be added in a modular fashion to the existing MC Hand, and ETD already developed and used extensively in the field.