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Figure 2 | BioMedical Engineering OnLine

Figure 2

From: In vivo myograph measurement of muscle contraction at optimal length

Figure 2

a-d: Constructive elements. Fig. 2a shows the apparatus in side view, having removed the front cover plate; Fig. 2b shows a detailed sectional view of the infinitely variable adjustable stopping mechanism; Fig. 2c shows the top view onto the extremity-setting of the apparatus as does Fig. 2d after removal of the arm rest plate. List of technical components (colors in brackets): (1) = axle (yellow) (2) = laser beamer (red) (2a) = swivel arm (lavender) (3) = thumb lever (dark gray) (4) = supporting cushion (blue) (4a) = supporting cushion mount (blue) (4b) = adjustment motors (light blue) (4c) = setting measuring gauge (green blue) (5) = stopping mechanism unit (5a) = bolt on axle (yellow) (5b) = isometric stopping bolt (green) (5c) = adjustment wheel (green) (5d) = adjustment motor (green) (5e) = stopping mechanism gauge (green) (6) = beam-measuring gauge (gray) (7) = potentiometer (8) = adjustable friction clutch. Fig. 2a,c,d show the adjusting and extremity-setting design. The thumb can be set at the thumb lever (3), which is fixed to the main axle (1) around which it can rotate. The setting elements (4) are for the setting of the hand and arm. The supporting cushions lead to the extremities and lock in place via mounting blocks (4a). Electro-motors hold the arm into place (4b) and the muscle position is determined via the splint-measuring gauge (4c). At the end of both the apparatus axle (1) and the end of the swivel arm (2a), there are lasers (2), whose beams elongate the apparatus axle and project onto the extremity (hand) to be inserted. Fig. 2c shows the right arm and hand set in position. The cushions are symmetrically assembled for adjustment and setting of the left arm and hand. To achieve this, the arm rest plate is moved to the right, ensuring the left arm is over the axle. Fig. 2a-b show the pre-stretching and isometric stopping mechanism which consists of an isometric bolt (5b) which can be variably adjusted by means of an adjustment wheel (5c) and adjustment motor (5d). Thus the isometric bolt (5b) takes the stopping bolt of the axle (5a) with it and, therefore, indirectly rotates the axle (1) and the thumb lever (3) into the desired position. An adjustable friction clutch (8) prevents an overstretching of the muscle.

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