Patent ID: 11886151
Assignee: ETA SA MANUFACTURE HORLOGèRE SUISSE
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. The wheel set system according to claim 1,
wherein the pivots have a rounded tip, the rounded tips of the two pivots having identical radii Rb, Rh,
wherein μb is a friction coefficient of the first bearing and μh is a friction coefficient of the second bearing, and
wherein the contact angles αh, αb are defined by the following equations:, tan
      ⁢
      
        
      
      ⁢
      
        α
        b
      
    
    =
    
      
        BH
        _
      
      
        4
        ⁢
        
          
        
        ⁢
        cos
        ⁢
        
          
        
        ⁢
        
          π
          N
        
        ⁢
        
          
        
        ⁢
        
          GH
          _
        
      
    
  

  
    
      tan
      ⁢
      
        
      
      ⁢
      
        α
        h
      
    
    =
    
      
        BH
        _
      
      
        4
        ⁢
        
          
        
        ⁢
        cos
        ⁢
        
          
        
        ⁢
        
          π
          N
        
        ⁢
        
          
        
        ⁢
        
          GB
          _
        
      
    
  

  
    
      
        R
        h
      
      
        R
        b
      
    
    =
    
      
        
          μ
          b
        
        
          μ
          h
        
      
      ⁢
      
        
          GH
          _
        
        
          GB
          _
        
      
    
  

where N is the number of faces of the two pyramids, BH is a distance between the ends of the two pivots, GH is a distance between the end of the first pivot in contact with the first bearing and the mass centre G of the balance, and GB is a distance between the end of the second pivot in contact with the second bearing and the mass centre G of the balance 2.