Abstract: A process and an apparatus for welding straps of thermoplastic plastics, wherein the supply of heat which is necessary for welding is controlled depending on the thickness at the weld of the straps which are to be welded to each other and is not switched off until said thickness falls below a predetermined set value.

Abstract: In order to arrive at an eccentric mechanism which ensures that the eccentricity or the connecting rod stroke position is adjustable and after turning off the eccentric mechanism always is identical to the one before turning on the eccentric mechanism, the invention proposes that the cylinder shaped eccentric (16) of the eccentric shaft (10) is pivoted in the cylinder bore of an eccentric bush in a manner that ensures that when the eccentric mechanism is at a standstill concentricity is obtained when the eccentricities of the eccentric shaft and the cylinder bore of the eccentric bush cancel each other out while when the eccentric shaft (10) rotates due to the centrifugal force on at least one actuator (27) a counter-rotation of eccentric shaft and eccentric bush occurs automatically due to the centrifugal force while canceling the concentricity and the eccentricity becomes effective on the main drive pinion of the eccentric mechanism or vice versa.

Abstract: A device for tensioning and securing the ends of packing straps which are pressed by a pressure plate against a tensioning wheel. The pressure plate is designed to be lifted off of the tension wheel by the operating lever thereby allowing rotation of the tensioning wheel via an actuator element, thus enabling insertion of the strap ends into the tensioning device. This arrangement makes a special release lever unnecessary.

Abstract: A band-tensioning device is disclosed which includes an operating lever rotationally fast with an eccentric which is pivotable about a fixed axis. An angle lever is provided which is freely pivotable about the eccentric, and urgeable to rotate therewith by means of the operating lever. A lower portion of the angle lever has an abutment surface which can cooperate with the friction surface of a rotatable tensioning wheel to force a band to be tensioned against the rotating wheel. The pivoting of the eccentric relative to the angle lever displaces it transversely to the abutment surface, so that the surfaces become separated and thus disengaged without having to overcome the high wedging forces associated with the tensioned band between the surfaces. The levers may be coupled by means other than the eccentric, e.g., via an articulated lever, provided the angle lever is selectively movable pivotally or transversely to the abutment surface.

Abstract: A feed device for strapping bands for use in strapping machines is disclosed. A pressure device and a feed roller push the strapping band into a band channel behind the feed roller. A disengaging lever is connected to the pressure device so that when a loop in the band is formed in the band channel, it moves the disengaging lever causing the pressure device to be withdrawn from the band and feed roller permitting the band to reverse direction causing the loop to disappear.

Abstract: An apparatus for securing a tensioned plastic band which has a rotatable tensioning wheel and a friction shoe which is located adjacent a band path for two mutually overlapping end portions of a band located around an article is disclosed. The shoe is reciprocatable transversely to the band path, and displaceable into and out of contact with the upper band end portion. A single drive means is permanently coupled to the shoe for reciprocation, and drives the tensioning wheel via a torque-sensitive coupling. In operation, the shoe is initially out of contact with the band, and the wheel is driven so as to tension the band until a predetermined tension is reached. Thereupon the coupling uncouples, and actuates means which urge the shoe against the band. This causes relative motion of the band ends, resulting in their being frictionally welded together. The uncoupling also actuates a cutting member for the band. Thus the sequence of tensioning, welding and cutting is performed automatically.

Abstract: A device, for feed and tensioning a strapping band about a package in a strapping machine, is disclosed. The machine includes a feed roller which is actuately deflected when the band is placed under tension by a tensioning device. The tensioning device includes a pair of counter rotating v-belts between which the band passes and a pressure device which causes the band to be gripped by the v-belts thus placing it in tension. As the tension on the band increases the pressure exerted by the pressure device is proportionately increased by an angular lever to which the feed roller is connected, which in turn acts on a slidable rod which, through a toggle lever, actuates the pressure device. The machine also includes a sealing and cutting device which is actuated subsequent to the tensioning of the band and which, through a rocker lever, causes the toggle lever to release the pressure on the pressure device prior to the cutting of the rear end of the band.

Abstract: Apparatus for the welding of strips of thermoplastic material lying on top of each other which enables varying of the welding area and wherein the contact area between the jaws and the strip is larger than the welding area. One jaw is fixed and the other jaw is swingable about a vertical axis through the strip while in pressure engagement with the ends of the strips to be welded.

Abstract: A device for friction welding together two plastic strips which provides a weld having a strength approaching that of the strips. Movable friction jaws are oscillated on axes perpendicular to the plane of and through the strips with the result that the frictional motion is greatest in the middle of the welding zone and decreases almost to zero toward the ends of the welding zone.

Abstract: A method and apparatus for joining the strip ends of a plastic strip using a piece of wire cloth overlaying the end. The front edges of the wire cloth are bonded to the plastic strip to a lesser degree than the median portions of the cloth by either heating the ends less or pressing the ends against the plastic strip to a lesser degree than the median portions.