Patent GB-1515930-A (GB)
Title: Blow-moulding unit for synthetic plastics materials
IPC: B29L22/00
Filed: 1975-10-31
Abstract: 1515930 Clamping devices for blow moulds BEKUM MASCHINENFABRIKEN GmbH 31 Oct 1975 [14 Nov 1974] 45366/75 Heading B5A In a blow moulding unit, of particular use in a blow moulding device in which relative movement is necessary between the unit and the extruder and blowing mandrels, the mould sections are slidable along guide rods located assymetrically with respect to the mould face and a clamping device is provided which during said relative movement does not obstruct the space between the mould sections but which during clamping helps apply a symmetrical closure force to the mould. In one embodiment, see Figs. 2 (and 3), the halves of a blow mould 1a, 1b are carried by plates 2 and 3. Plate 3 is actuated directly by a cylinder 10 and is slidable along a pair of guide rods 4 carried by the plate 2, the rear ends of the guide rod being connected to a support plate 5. Plate 2 carries fixed thereto part 13 of a divided tie bar, the part having a locking head 15. The other part 14 of the tie bar is slidably mounted through the plates 3 and 5 and carries at its front end a set of jaws 17 engageable with the locking head 15, at its rear end a member 21 and intermediate its ends a collar (26). The part 14 is biased forwardly by compression spring 20 to the position shown in Fig. 1. In use when the mould has reached the almost closed position of Fig. 2 the jaws and locking head are paired for engagement and the member 21 has been abutted by the support plate 5. Upon further mould closure relative movement between a sleeve 24 carried by plate 3 and the part 14 causes rollers 25 carried by the sleeve to close the jaws on to the head thereby locking the parts 13 and 14 together into a unitary force transmitting clamping rod located so as to compensate for the asymmetric location of the guide rods. In a second embodiment, see Fig. 4, the locking head 15 is replaced by a rotatable locking member 34 and the jaw and sleeve arrangement is replaced by a socketed member 38, 39. In use, when the mould is nearly closed, the locking member is received in the socketed member and rotated to lock the two into a unitary tie bar. In a third embodiment (see Fig. 5), mould halves 40a, 40b are operated through cylinder 48 actuated links 49a, 49b, mould half 40b being carried by guide rods 44, 45 connected to a support plate 46 engaged by link 49b. A tie bar 50 is pivoted at one end to a projection 51 carried by the support plate and at the other end carries a part 52 engageable with a plate 53 mounted to the rear of mould half 40a. The plate 43 supporting the mould half 40b is provided with a rearwardly facing console 59 on which a shaft 57 carrying a toothed segment 60 is mounted. The segment engages a fixed rack 62 projecting from the machine frame 47 so that as the mould closes the shaft is rotated. The shaft carries an arm 56 provided on its end with a sleeve 58 through which the bar 50 slides and rotation of the shaft upon mould closure causes the arm 56 to pivot to push the bar upwardly and seat the part 52 in the plate 53. Further closure of the mould with movement of support plate 46 clamps the mould shut through the tie bar. Mould halves of different thicknesses are accommodated by forming the arm 56 in two parts held together by a spring.