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Power-Actuated Nasal Spray

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A consumer of medical services has chronic, severe allergies and has to take medication 2x a day through a nasal spray. She also has extreme RSI and cannot squeeze the halves of the nasal spray together (plastic top over glass bottle) to generate the pump action. In addition, the halves need to be squeezed rapidly and forcefully to generate the proper dose in a mist form that can travel far enough into the nasal passage. The device has to be small enough to enable the user to transport it to work and on business trips. Her RSI mandates that the activation be accomplished with only very light forces.


The center of the solution is an AC-powered solenoid. A box built around this mechanism holds the spray bottle firmly under a U-shaped "yoke" which is constructed of aluminum flat bar and moves up and down within aluminum channels on either side. The bottom ends of the yoke are attached to a bar that extends through the movable arm of the solenoid. A switch is provided on each side of the box to allow use of either hand, as requested. A larger, hinged paddle mounted over each switch reduces the force required to depress the switches.

The main challenge in this design was to determine the size solenoid to use. The first one that was tried was strong enough to pull the top down, but without quite the right amount of initial force to generate a good mist. (Even though the top only moved up and down 1/4 inch, the pull force of a solenoid arm diminishes rapidly with the distance away from the core.) A larger unit provided enough force, but was much louder and generated quite a "clank" on activation, causing the user to jerk her head up away from the nozzle. Efforts to mute the solenoid or insulate the box were not successful. The consumer took to using simple ear plugs and later got used to it.

Cost Analysis

Materials: Under $50

Labor: 8 hrs

Repeatability of Solution

The interior of the box and yolk would have to be tailored to each style of spray, but given the hand function required to operate these and oral inhalers, there is undoubtedly a need for this type of device. The basic concept is applicable in various situations. (In fact, I first used this method to help someone with very limited hand strength connect two sections of a telephone headset cord together.)


Ray Grott, MA, ATP

Rehabilitation Engineering & Technology Project

San Francisco State University