Abstract: An acoustic diaphragm is made of metallic sheet material forming a raised pattern of the material and unraised sectors of the material. The diaphragm is of the dome-shaped variety. The raised pattern incorporates sets of raised strip elements. There is a set of such elements extending radially from the vicinity of the apex. There is a set extending along areas of the sheet material between the radially extending elements, this second set including pairs of strip elements which intersect one another along such areas. There is also a set of circumferentially extending raised strip elements. The form of the radially extending elements changes along their lengths; for example, they rise to levels which vary along their lengths.

Abstract: The bone substitute material on the base of natural bone is rendered completely free of albumin and antigen by premaceration, pyrolization and sintering and its frame work consists of only the natural mineral structure of the natural bone.In the process of production of this bone substitute material the bone pieces are submitted to a pretreatment with warm water for removing of the soft parts, subsequently takes place a dealbumination by means of a solution of 10 to 30% H.sub.2 O.sub.2 in a shaking machine and a degreasing with ether. The bone pieces treated in this way are subsequently submitted to a combustion in a stove at 400.degree. C. to 1500.degree. C. and then to a sintering.This bone substitute material which may exist in the shape of the bone part to be replaced forms a form stable matrix for the bone regeneration in which only pure "mineral bone" is present so that no immunogen reactions can take place.

Abstract: The invention relates to a fire detector having a measuring chamber defined by two electrodes, so that a non-ionizing electric field is produced between the electrodes by a DC voltage source. The measuring electrode is connected to the input of a current measuring device without direct connection with the DC voltage source. As soon as charged particles of smoke penetrate into the measuring chamber between the electrodes, the electric field causes the positive and negative particles to drift. The charge drift induces a current into the measuring electrode which is measured.

Abstract: Apparatus is provided in which booklets of interleaved cigarette papers can be made from continuously moving strands of strip paper in which a cutting knife used to sever the paper strips precisely follows movement of the strip. Movement of a driven input shaft is brought onto the moving platform and used to operate the cutting knife. Paper from bobbins is converged by formers and a spreader into a strand advanced by nip rolls through a cutting station. The knife in the station cuts a booklet from the strand while the station moves with the strand. A driven rotatory shaft of non-circular section transmits its rotation to a sleeve that slides therealong as the station reciprocates relative to a shaft. The sleeve is operably connected e.g. by gearing or by a cam and follower to the knife so that rotation thereof brings about the cutting movement.

Abstract: The foldable bed has a frame including pairs of upper and lower U-shaped supporting tubes, each pair forming a substantially rectangular structure for fixing a cloth forming the side wall of the bed. The supporting tubes are pivotably connected with and supported by two U-shaped legs. The upper supporting tubes and the legs are interconnected by struts locking the upper supporting tubes in a horizontal position when the bed is in its open state for use. The connection between each strut and the adjacent leg is made by means of a sliding member slidable along a side-piece of the leg. This slidable connection between each strut and the adjacent leg substantially facilitates folding and opening the bed and minimizes the danger of hurting the user or a child in the bed.