Patent GB-445744-A (GB)
Title: Improved manufacture of container caps for bottles, jars and other receptacles
IPC: B21D51/44
Filed: 1935-07-08
Abstract: 445,744. Stamping bottle &c. caps. TENNANT, W. J., 111, Hatton Garden, London.-(Crown Cork & Seal Co., Inc. ; Highlandtown, Baltimore, U.S.A.) July 8, 1935, No. 19517. [Classes 83 (ii) and 83 (iv)] [See also Group XVII] A container cap of the lug type has a depending skirt 26, Fig. 5, the lower margin of which is curled inwardly entirely around the skirt and then upwardly to form an internal wire or bead 28 with the edge concealed therein, portions of this upwardly extended margin at circumferentially spaced points being less curled than the rest of the bead and extending farther inward radially to constitute the lugs 31. At least the lower portion of the skirt is of uniformly cylindrical contour and the crosssectional curve of the curl between the skirt and the substantially lowermost circumferential line of the curled margin is substantially constant at all points around the circumference. The cap is made from a blank having a top 25 and skirt 26 with raw edge 35, Fig. 11, by bending the edge 35 slightly inwardly, then forming a substantially semicircular inwardly disposed curl and substantially closing this roll or bead, Fig. 15, except at certain spaced points 37, Fig. 14, which later form the lugs, and finally bending the the incipient lugs 37 inwardly, Fig. 16. The cap is formed in apparatus cnmprising a block 50, Fig. 19, a nest 51 supported by a spring-pressed plunger 52 and a die-forming assembly hung from a cross-head 54 and comprising a cylindrical die 55 having a forming groove 56: A rod 57 carrying a clamping pad 59 is normally projected downwardly by a compression spring 58. A sleeve 60 has its lower end formed with a cam surface 61 to engage a surface 64 on expanding fingers 62 formed integral with a ring 63. When the die assembly descends, the pad 59 holds the cap top 25 against the nest 51 and depresses the nest and blank into the socket in the block 50, the spring 58 then being compressed and moving the sleeve 60 relatively to the fingers 62, camming them outwardly against the cap skirt. The groove 56 then gives the edge 35 of the blank a slight inward bend. A one-piece stationary nest 51<1>, Fig. 24, may be used instead of the block 50 and nest 51, while an air blast may be provided to eject the finished blank. At the next station the edge is beaded and then a die, Fig. 22, having aligned grooves 71, widened portions 72, rounded shoulders 73, and cutaway portions 70 serves to complete the bead and start formation of the lugs which are completed by the action of a die 55" co-operating with fingers 62<1> having heads 651, Fig. 24. Alternatively, a bead may be formed round the complete circumference and then unrolled to form the lugs. In another modification, after the partial bead 30<1>, Fig. 12a, has been formed certain circumferentially spaced portions 31<1>, Fig. 13a, are bent outwardly, the subsequent operation of completing the curl or bead, Fig. 14a, serving to draw the portions 31<1> bodily inwards, Fig. 15a. The lug-forming portions 31<1> are bent outwardly by the apparatus shown in Fig. 25, and comprising a nest 51 and sleeves 70', 72<1>, the latter having four elongated recesses in which pairs of levers 74', 75<1> having feet 82, 84 are pivoted at 76', the lever 74<1> being normally retracted by a spring 77. A cam surface 78 on each lever 74<1> is engaged by a shoulder 79 on the sleeve 70<1> just before the surface 80 of the lever 75<1> is engaged by a corresponding cam 81. When the assembly descends, the sleeve 72<1> first contacts with the nest, 51<1> then the spring 85 is compressed and the shoulder 79 engages the surface 78 and moves the foot 82 inwardly, Fig. 25, and then the surface 81<1> engages the surface 80 and each foot 84 is forced outwardly. A later pressing operation then completes the curl or bead of the undeformed parts and the force impressed on these parts serves to turn the lug portions bodily inwards.