Patent ID: 11965774
Assignee: COVENTRY UNIVERSITY
Field: Medical technology (Instruments)
Classification: CPC G  A | IPC A  G

Claim 0:
1. A vibration dose measurement apparatus suitable for use by a machine operator, the apparatus comprising:
a sensor assembly; and
a support operable, in use, to urge the sensor assembly toward the palm of the operator wherein the sensor assembly comprises an accelerometer operable to detect linear motion;
a gyroscope operable to detect rotary motion; and
a gripping force sensor operable to detect gripping force applied by the operator,
wherein the apparatus comprises a processor connected to the outputs of the accelerometer, gyroscope and gripping force sensor, the processor operable to receive and process output signals from the accelerometer, gyroscope and gripping force sensor so as to determine whether a safe vibration dose is exceeded, wherein the vibration dose is calculated based on a modified A(8) value including an additional term derived from the gripping force sensor output, wherein the modified A(8) value is defined by the formula, A
    ⁡
    (
    8
    )
   
   =
   
    
     
      a
      
       h
       ⁢
       v
      
     
     ⁢
     
      
       T
       
        T
        o
       
      
     
    
    +
    
     
      
       V
       
        E
        ⁢
        T
       
      
      ⁢
      T
     
     
      ρ
      ⁢
      
       A
       s
      
      ⁢
      
       A
       h
      
     
    
   
  
  ,
 

where ahv is the total vibrational vector characterising a particular vibration, T is time that an operator is exposed to the vibration characterised by ahv, To is a reference time value, VET is the vibrational energy transmitted determined from the gripping force sensor output, ρ is the density of the operator's palm skin tissue, As is the area of the operator's skin in contact with the machinery, and Ah is the area of the handle of the machinery.