Patent GB-1316151-A (GB)
Title: Apparatus for friction welding thermoplastic container parts
IPC: B29C65/00
Filed: 1970-06-01
Abstract: 1316151 Seaming non-metallic sheet material KOEHRING CO 1 June 1970 [5 June 1969] 26229/70 Heading B5K Apparatus for friction welding thermoplastic container parts 10, 11 together comprises axially aligned holders 20, 21 for the parts 10, 11 and mounted for relative axial movement to bring the parts 10, 11 into engagement for friction welding; means for rotating the holder 21 relative to the holder 20 to friction weld the engaged parts 10, 11; means to supply the parts 10, 11 to the holders 20, 21, respectively; and radially constricting means 40 operative before and after the parts are engaged for radially clamping and releasing the part 10 in the holder 20, the means 40 being movable from a radially expanded position freely receiving the part 10 to a radially constricted position clamping the part 10 in position. Preferably, the yoghurt container to be formed comprises a tubular frusto-conical top part 10 and an inverted-cup-shaped bottom part 11, Fig. 7. In operation, the parts 10 are fed on a conveyer 13, Fig. 1, and are forced by the parts behind to a star-wheel disc 27, Fig. 2, which moves them along a shelf 25. A continuously rotating carrier 22 orbits a holder 20 to a position in which a member 38 on the holder 20 commences to move axially downward over a part 10 on the shelf 25. When a part 10 reaches a roller assembly 58, urged at an upwardly inclined angle by a spring 58b, it is assisted upwardly into the member 38 by the assembly 58. As each member 38 continues to move orbitally, it forces the assembly 58 downwardly to the broken line position of Fig. 2. A diaphragm assembly 44, Fig. 5, is connected to a suction source via a line 51 so that a diaphragm 47 retracts a rod 48 and a band 40 within the member 38 is tightened around the part 10. At the same time that the part 10 is fed to the holder 20, the parts 11 are moved in a line along a conveyer 12, Fig. 1, to a star-wheel disc 26, Fig. 2, which moves them along a shelf 25<SP>1</SP>. As a part 11 leaves the edge 25a<SP>1</SP> of the shelf 25<SP>1</SP>, it engages a suction duct 52 so as to be held thereby. The part 11 engages a concentrically disposed finger 55 provided for each holder 21 and is forced to travel in the orbital path, of a mandrel 35 of a holder 21. The finger 55 aligns the part 11 on the mandrel top 35b. Whilst the part 11 is moving along the duct 52, the holder 21 is raised and, as the top 35b enters a part 11, a pulley 36 on the mandrel is engaged by a stationary nylon pad (62), Fig. 3 (not shown), and is rotated a sufficient amount so that ribs 63, Fig. 2, on the top 35b engage grooves 11a, Fig. 7, in the part 11 to prevent relative rotation between the top 35b and the part 11. As the top 35b moves into the part 11, suction is applied through openings 35c to assist the location of the part 11. As the mandrel 35 continues to orbit on the carrier 22, its pulley 36 engages a continuously driven belt 37 and is rotated thereby. When the pulley 36 leaves the belt 37, the rotating mandrel 35 is moved upwardly to engage the part 11 within the part 10 and friction weld these parts along a line a, Fig. 7. When welding has taken place, the mandrel 35 stops rotating, suction is discontinued from the openings 35c and the mandrel 35 is moved downwardly. The holder 20 is moved to a discharge star-wheel disc 19, Fig. 1, and the suction source is disconnected from the line 51, Fig. 5, so that a spring 50 can return the band 40 to its disengaged position and the welded parts drop from the member 38. During welding, the part 10 is rotated counter-clockwise of Fig. 5 so as to tend to tighten the band 40 about the part.