| 摘要 |
<p>The appts has holders for the instruments when not in use, and whip-type retractors for their supply pipes or cables. A spring attached by a rope to each whip arm gives retraction torque varying with the arm angle, the power or medium supply to the instrument is cut in after the arm has hinged through a predetermined angle. Each whip arm (5) has a cam (6) coaxial to and turning with it, and to which the rope is attached (12), so as to be wound onto it through an angle varying with the arm angle, and to vary the amount of leverage, and thus the torque, by the alteration in distance between the hinge axis (3) and the point where the tope first touches the cam. At every angle of the arm there is contact between the cam and the face (25) of the cutting-in switch (8).</p> |
