Combination Possibilities; Adjustments And Final Assembly; Service Directions; Lubrication - Otto Bock 3R20 Instructions For Use Manual

4.2 Combination possibilities

INFORMATION
In a prosthesis, all prosthetic components have to meet the patient's requirements regarding the
amputation level, body weight, activity level, environmental conditions and field of application.

4.3 Adjustments and final assembly

Contrary to single-axis knee joints the 3R20/3R36 Modular Knee Joints are stable from heel strike
to mid-stance phase. During roll-over of the foot knee flexion is initiated. The position of the ante-
rior and posterior linkage bars to each other and thus the location of the instantaneous centre of
rotation determine knee stability and initiation of flexion.
By varying the point of contact of the Extension Stop (5) stability of the knee joint can be adjusted
according to the individual requirements of the patient. To provide swing phase adjustment the
axis friction and extension assist tension may be regulated separately.
Before adjusting the knee joint, read the following instructions:
4.3.1 Adjusting stance phase stability with extension stop setting (Fig. 2)
To vary the position of the knee extension stop, turn the Adjustment Screw (5) using a 4 mm hex
head wrench.
Clockwise rotation
Counter-clockwise
rotation
4.3.2 Setting swing phase speed with Axis Friction adjustment (Fig. 3)
The axis pins are located in maintenance-free Knee Axis Bushings (10) and are attached by a
Cap Screw (9) each to Washer (22) and Lock Nut (18). The bearing allows adjustment of the
axis friction (resistance to motion) and readjustment of tolerance variation.
Fix Lock Nut (18) using enclosed Wrench (23), and turn Cap Screw (9) using a 5 mm hex head
wrench.
Clockwise rotation
Counter-clockwise
rotation
Adjustments of as little as 5° to 10° provide a perceptible change.
4.3.3 Regulating the swing phase with Extension Assist adjustment (Fig. 4)
Adjust the tension of the Spring for Extension Assist (12) by turning the Adjustment Screw (13).
Use a 4 mm hex head wrench. The maximum depth of the adjustment screw in the Spring Housing
(14) should not exceed 8 mm.
To have a lower effect from the extension assist, the 513D34=L (12a) Extension Assist Spring can
be ordered.

5 Service directions

5.1 Lubrication

Apply 633F16=0.250 Lubricant to all moving metal surfaces in the modular knee joint.
Sparingly apply 633G6 Lubricant to the axis pins in the cone shaped bushings (10).
14 | Ottobock
= decreases stability of the joint
(initiation of flexion becomes easier).
= increases stability.
= increases friction
= decreases friction
3R20, 3R36