Abstract: A method of producing a plastic pin, including a bowling pin, having a cellular and/or porous core that is surrounded by a solid-walled, noncellular and nonporous shell. The shell is initially produced as a whole body in a mold. While the material of the shell is not yet hardened and is still deformable, an insert is introduced into the narrowed neck portion of the shell, in a direction axial relative thereto, in such a way that the insert displaces an inner layer of the shell, dividing the hollow interior of the shell into an upper and a lower chamber and producing a fixed connection with the material of the shell. Material for the core, with such material being provided with an expanding agent, is then introduced into the shell, and after the shell and the core have set, the mold is removed.

Abstract: A roller belt arrangement for a caterpillar track-type vehicle, especially a snowmobile. The arrangement has one or more inextensible belts that extend parallel to one another and to which transversely extending drivers or grippers are secured with the aid of screw bolts that extend through the belts and a base of the driver or gripper. The base has a U-shaped cross-sectional shape, including two legs that extend essentially perpendicular to the belt and a crosspiece that connects the legs and extends parallel to a plane of the belts and is adapted to rest thereagainst. An elastomeric cushion member is provided that rests against the crosspiece on the side thereof remote from the belts. An abutment member is disposed on an end of the screw bolt facing the driver or gripper, with the cushion member being disposed between the abutment member and the crosspiece.

Abstract: An eccentric screw pump having a rigid rotor, which is embodied as a spiral and has a circular cross-sectional configuration, and also having a stator that is provided with an elastic lining that delimits a cavity which accommodates the rotor and has the form of a spiral with a cross-sectional configuration that essentially has the shape of a rectangle bounded on opposite sides by a respective semicircle. The sides of the essentially rectangular portion that interconnect the semicircles, proceeding essentially from the semicircles, are provided with projections that bulge convexly in a direction toward an interior of the cavity of the stator. In the vicinity of the inlet end of the stator, the projections bulge inwardly to a lesser extent than at the pressure side of the stator.

Abstract: An apparatus for aerating water, including a rigid, at least essentially planar support element upon which is disposed a sheet of elastomeric material that is provided with fine slits for the discharge of air. The support element has one or more connectors for supplying air between the support element and the sheet. The rim portion of the sheet is connected in an airtight manner to the support element. Provided at various locations inwardly of the rim portion of the sheet are one or more holding mechanisms for limiting or preventing a lifting of the sheet from the support element. This holding mechanism is in the form of a projection that is disposed on the underside of the sheet and is connected to the support element in an interlocking and/or frictional manner.

Abstract: A method and apparatus for producing conveyor belts having rigid carriers is proposed. The conveyor belts have elastic cover layers and are provided with fasteners that overlap the carriers to hold the same. The fasteners are first connected to the conveyor belt, whereupon the carriers are forced between the conveyor belt and the fasteners, accompanied by elastic deformation of the cover layer. This considerably simplifies the mounting and fixation of the carriers.

Abstract: A connection arrangement to provide an endless belt, especially for a screening rod belt. The band ends are securely disposed between essentially U-shaped fittings that are held together by a transverse pin. To better utilize the band strength, the lateral edges of the legs of the fittings are provided with bent portions against the greatest portion of which the side surfaces of the bands rest. Securement elements are used for the fittings and the band ends, and are driven in the manner of nails accompanied by displacement of material.

Abstract: A roller belt arrangement for caterpillar track-type vehicles and having several rotating belts that are connected via grippers that guarantee a positive drive and are secured to the belts via screw bolts. To prevent lateral bulging of the belt from occurring during securement of the grippers, which bulges lead to undesired shearing stresses in the belt body, in the vicinity of lateral edges of the gripper and/or their securement elements, the rubber cover layers are provided with notches that extend along the edges and prevent or reduce the stresses in the belt body caused by the bulging.