AntiVib Air Bladders

ANTIVIBRATION AIR BLADDERS

ErgoAir^® AntiVib^® Air Bladders

Repetitive trauma associated with bumps, jolts, and excessive vibration to the hand is a major health problem in the United States. According to the National Institute for Occupational Health and Safety (NISOH), from two to four million workers in the U.S. are exposed to on-the-job vibration directed into the hands. Many of these workers have or will develop symptoms associated with hand-arm vibration syndrome (HAVS). HAVS is associated with the destruction of the small blood vessels and with nerve damage in the fingers caused by long-term exposure to excessive vibration directed into the hands. In addition, millions more suffer from other hand and wrist disorders, such as, carpal tunnel syndrome, tendonitis, de Quervain's disease, and Duputryn's contracture. All of these disorders often result in discomfort and pain, and they often interfere with social, household, and sports activities that require the use of the hands. Even though persons may not have hand-related health disorders, they may experience significant tingling and numbness in their fingers and fatigue in their hands and wrists when they participate in activities, such as, mowing their lawn, cycling, driving cars and trucks, and riding off-terrain vehicles, snow mobiles, dirt bikes, and motorcycles.

Drs. Douglas Reynolds and Tom Jetzer have designed and developed the patented ErgoAir^® AntiVib^® air bladder. This air bladder, when used in gloves, helps to reduce the discomfort and pain associated with all of the above health disorders and the discomfort and fatigue associated with outdoor activities that result from exposure of the hands to bumps, jolts, and vibration. The ErgoAir^® AntiVib^® air bladder is shown in Figure 1. The bladder is made from two thin layers of flexible urethane thermoplastic film that are bonded together by means of precision RF welding. The inflated thickness of the bladder is controlled by the spacing between the weld points in their grid patterns in the palm, finger, and thumb sections of the bladder. Properly placed weld lines give the bladder flexibility to comfortably conform to the contour of the hand when it is placed in a glove. The bladder is inflated by means of the pump in the integral bladder inflation mechanism. The bladder can be deflated or the air pressure in the bladder can be adjusted by means of the release valve.

Figure 1 ErgoAir^® AntiVib^® Air Bladder

The ErgoAir^® AntiVib^® air bladder shown in Figure 1 is used in full finger gloves. This bladder is manufactured by Dielectrics Industries of Chicopee, Massachusetts. Figure 2 shows a picture of a pair of motorcycle gloves that contain ErgoAir^® AntiVib^® air bladders. These gloves are manufactured by Olympia Sports, Inc. of Elmsford, New York. Half and three-quarter finger bladders are also available for use in half and three-quarter finger gloves.

Figure 2 Gloves with AntiVib^TM Air Bladder

The ErgoAir^® AntiVib^® air bladder is placed in a pocket between the palm of the hand, fingers, and thumb and the outside shell of the glove. A thin layer of cotton or Lycra^TM material is placed between the bladder and the hand to prevent the hand from sweating. The outside shell of the glove can be any type of durable material.

Many glove manufacturers claim to have industrial and sports gloves that protect the hands and wrists from bumps, jolts, and vibration. Some of these gloves are marginally effective; many do not work at all. To address this issue, the Organization of International Standardization (ISO) developed ISO Standard 10819 and the American National Standards Institute developed ANSI S3.40. These standards specifies the test procedures that must be used and defines the performance criteria that must be met to label a glove as an antivibration glove. ISO 10819/ANSI S3.40 requires that an antivibration glove must:

• have an average ISO weighted vibration transmissibility value of less than 1 ( TR_M < 1) in the mid frequency range of 16-400 Hz and of less than 0.6 (TR_H < 0.6) in the high frequency range of 100-1,600 Hz.

• be a full-fingered glove that has the same vibration protection in the palm and fingers.

Gloves marketed in the European Union as antivibration gloves must meet the strict requirements of ISO 10819. There are currently no mandatory government regulations in the U.S. that control the labeling of gloves. ANSI S3.40 is a voluntary standard. Thus, many gloves that are marketed as antivibration gloves in the U.S. do not meet the requirements of ISO 10819/ANSI S3.40.

Table 1 - ISO Weighted and Linear Vibration Transmissibility Values

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Table 1 shows the measured ISO and linear vibration transmissibility values of gloves made with several different vibration reducing materials. Lower transmissibility values indicate greater effectiveness in reducing vibration transmitted to the hands. The ISO weighting filter used in ISO 10819/ANSI 3.40 tests de-emphasizes the higher frequencies while it emphasizes the lower frequencies in the mid and high frequency ranges. Thus, the ISO weighted transmissibility values tend to understate the effectiveness of a glove to reduce vibration transmitted to the hands. The linear transmissibility measurements equally weigh all frequencies within the mid and high frequency ranges specified by ISO 10819/ANSI S3.40. Thus, the linear transmissibility values represent a more realistic assessment of a glove's ability to reduce vibration transmitted to the hand. Figure 3 shows the vibration transmissibility values of gloves made with the vibration reducing materials listed in Table 1 as a function of third octave center frequencies.

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Figure 3 - Third Octave Vibration Transmissibility Values

The test procedures specified in ISO 10819/ANSI S3.40 are designed to examine a glove's effectiveness in reducing vibration transmitted to the hands in industrial environments. ISO 10819/ANSI S3.40 test results also give a good indication of how effectively a glove vibration reducing material will protect the hands from the bumps, jolts, and vibration a person will experience when he mows his lawn or when he rides a bicycle or motorcycle over a very long distance. Glove vibration reducing materials that perform well in industrial environments will normally perform well in household and sports environments.

Table 1 and Figure 3 indicate that gloves made with the ErgoAir^® AntiVib^® air bladder out performed gloves made with all other vibration reducing materials. Only gloves made with the ErgoAir^® AntiVib^® air bladder met the strict requirements of ISO 10819/ANSI S3.40 to be classified as an antivibration glove. The thin layer of air the bladder places between the hand and objects that direct bumps, jolts, and vibration into the hand reduces 70% of the energy they direct to the hand and wrist. The ErgoAir^® AntiVib^® air bladder is nearly massless, and it comfortably conforms to the contour of the hand when placed in a glove. Gloves made with the ErgoAir^® AntiVib^® air bladder provide a comfortable padding for the palm and fingers without interfering with gripping. They allow the wearer to feel what he is clasping, while at the same time they reduce the discomfort and fatigue associated with bumps, jolts, and vibration directed to his hands.

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