The vibration characteristics of chain saws and their influence on vibration white finger disease

Abstract

The vibration from chain saws can cause vibration-induced white finger disease (VWFD). Measurements of vibration levels on the front and rear handles of different chain saw-types, and on the operator's middle finger were collected at three logging camps on Vancouver Island. Factors effecting the vibration levels on the finger and handles were investigated. The acceleration at the firing frequency was found to be the dominant factor effecting handle and finger vibration. Other factors which were investigated were: grip force; the presence of handle covers; and chain sharpening procedure. Weighted acceleration levels are calculated and this information is used to assess the latency period for fallers to develop VWF disease.

Evidence for frequency-dependent arterial damage in vibrated rat tails

“…Sensory activity stimulates, via polysynaptic pathways, neurons in the rostral ventral lateral medulla to elicit norepinephrine release from peripheral sympathetic nerves, which activates smooth muscle contraction via ␣-1 receptors. Chainsaws with a dominant vibration frequency of 125 Hz can cause vasoconstriction blanching of the operator's fingers, the so-called white finger (Hyvarinen et al, 1973;Hutton et al, 1993). Pacinian vibroreceptors were suggested, without direct evidence, to activate the somatosympathetic reflex because they are readily stimulated by vibration at this frequency.…”

“…Studies of HAVS and animal models of vibration exposure suggest that injury may be vibration frequency (Hz)-dependent, although the findings are contradictory (Hyvarinen et al, 1973;Okada, 1986;Furuta et al, 1991;Bovenzi et al, 2000). While vibrating tools emit complex waveforms of amplitude, direction, and fre-frequency (Radwin et al, 1990;Hutton et al, 1993). In order to design safer tools and tool use guidelines, it is important to understand the role of frequency in the onset and progression of vibration injury at the tissue and cellular levels.…”

Muscoloskeletal Disorders of the Hand and Wrist in Ophthalmologists

“…Many studies have shown that exposure to HAV increases the rate of HAVS significantly. The majority of studies of the relationship of HAV to HAVS have been done on workers using large tools, such as workers in the lumber industry using chain saws [7,8], stone-cutters using rock drills and chisel hammers [9], and hand tools used in the automobile industry [10]. Vibration from tools used in these industries is higher that vibration produced by tools used by dentists or ophthalmologists; however, HAVS is dependent not only on the intensity of the vibration, but also on duration of exposure, variation of intensity over time, work methods, work processes, and posture during use.…”

Evaluation of hand‐arm vibration (HAV) exposure levels among grounds maintenance workers: An observational human exposure measurement study

“…However, there are no standardized methods for HAV exposure assessment. Many studies traditionally have measured acceleration values directly from tools by mounting an accelerometer on the tool handle 2–6 while more recent studies have measured vibration magnitude at the hand‐handle interface using hand‐held/hand‐mounted adapters in which an accelerometer is attached to or inserted 7,8 . Most recently, vibration dosimeters integrated with hand adapters 9,10 are available which enable to obtain daily exposure dose while minimizing interference with job activities.…”