Telefonaktiebolaget Lm Ericsson (publ)

Ab Svenska Flaktfabriken

Karl Gustaf Olsson

Stig C Ernolf

Bertil S Larsson

Bjorn T Kassman

Per-Ove Nilsson

Torbjorn R Olsson

Stefan J Bokfors

Lars H Widoff

Rolf I Kjellsson

The present invention relates to a printed circuit board provided with electrical contact devices (7) and intended to be mounted in the back plane of a card frame (2) such as to form a magazine (1) in which printed circuit cards (6) having electrical contact devices (8) corresponding to the contact devices (7) on the board can be inserted at right angles to the back plane. The circuit board (3) forms an electrical connecting unit for the circuit cards in the back plane of the magazine. In accordance with the invention, the circuit board is configured to provide a self-supporting and stiffening structure in the form of a sandwich element (10).

Printed circuit board for mounting in a backplane

In a dust extraction system for woodworking machinery, the dust is collected by a hood over each machine and is carried by an air flow produced by a blower through a branch conduit to a manifold which is common to a number of branch conduits. The manifold is made sufficiently large that the air flow velocity in the manifold is too low to carry the dust along the manifold, and therefore the dust collects at the bottom of the manifold, from which it is removed at intervals by a conveyor, which carries the dust to a central hopper. A control system keeps the subatmospheric pressure in the manifold substantially constant, so that the number of machines served by the system can be changed without affecting the system performance.

Apparatus for conveying waste materials by suction

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Stockholm, Sweden

Karl Gustaf Olsson