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2.5. The ball hinge emulation

The universal rest with the ball hinge is the best equipment for setting a bolster or a flat pillow. However its main assembly (the ball hinge) quite often is not available in domestic workshop. In that case the main unit can be emulated with own plate for every plane of controlling.

This idea many years is realized in devices for navigation of ships, airplanes, rockets, space vehicles. The device named “gyroscope” creates a bearing coordinate system on a moving object. The authors of the book naturally came to the same idea after testing numerous rests.

Despite of very “scientific” name the “gyroscope platform” can be domestic made of wood details. Drafts of a rest emulating the ball hinge were shown on the site klk.pp.ru at Russian lace maker’s request in 2006.

The rest contains three movable platforms. The first (lower) platform rotates on a table. The second (middle) platform is set on the thirst one and rotates at two pin axes. The third (upper) platform is set on the middle platform as well on two pin axes (Fig.2.38).

Fig.2.38. The rest for small bolsters

The tray for the bolster is attached to the upper platform. The bolster is plunged into the tray down to 0.3 … 0.4 of its radius. This depth is enough to fix the bolster without any additional contrivances. Variants of the rest are ahown on Fig.2.39, Fig.2.40.

Fig.2.39. The rest for small bolsrters

Fig.2.40. The rest emulating the ball hinge

The details of braking on heel and elevation angles are not shown. Brakes are fulfilled as metal sectors with soft plastic gaskets. Braking effect is achieved by squeezing sectors with screw-nut. The same effect would be created with an off-center device. It is desirable that bolster controlling would be pedal. Steadiness of rest is ensured with frames or skis attached to tables.