Patent GB-751114-A (GB)
Title: A machine suitable for forming rubber articles by dipping
IPC: B29C41/14
Filed: 1954-02-05
Abstract: <PICT:0751114/III/1> <PICT:0751114/III/2> <PICT:0751114/III/3> Relates to forming thin walled b rubber articles by dipping forms into liquid latex and consists in apparatus for imparting a predetermined path of movement to an article comprising a frame 10, a hollow shaft 31 mounted for rotation on the frame, a rod 28 of substantial length, means mounting the rod 28 on the frame 10 for <PICT:0751114/III/4> <PICT:0751114/III/5> <PICT:0751114/III/6> <PICT:0751114/III/7> rotary movement with the shaft 31 and linear movement with respect to that shaft, means for rotating the shaft 31, an arm 58 rotatably mounted on the rod 28 adjacent one end thereof, means carried by the arm 58 for attaching an article thereto, a second shaft 48 rotatably mounted on the frame 10 and within the shaft 31, means for rotating the shaft 48, and means interconnecting the shaft 48 and arm 58 for transmitting movement of the shaft 48 to the arm.  A chain coveyer 22 moves down one side of a latex tank 13, under it and under an adjacent tank 14 holding coagulant, and up the side of the tank 14.  In the space between the two parallel chains which form the conveyer a cross-bar 19 is pivotally hung from the chains, Fig. 14, and is of tapered section to receive forked projections 17, 18 from a rod 16 on which are secured forms 15 on which the articles are to be moulded by dipping and which, in the Example shown, are boot shaped.  As the conveyer descends a transverse plate 25 on one end of the rod 16 meets two platforms 168, 169, Fig. 5, and a transverse plate 172 on the other end meets platforms 170, 171, with the result that the bar 16 carrying the forms 15 is lifted off the cross-bar 19 and brought to rest and the conveyer moves on, the cross-bar folding back or passing under the tanks as shown in Fig. 1.  One of two similar arm assemblies 26, 27 then comes into action, by the movement of a lever arm 36, Fig. 3, which swings the hollow shaft 31 to which it is fixed and thereby moves the rod 28 at the end of which is a gripping device which is thus brought to the plate 25 which it grips.  The gripping device is shown in Fig. 3, which illustrates the arm assembly 26, and comprises a jaw 62 and piston rods 64, 65 which are extended by admission of compressed air to a cylinder 61 to clamp the plate 25 against the jaw 62. The device can rotate, as the arm 58, on a short hollow shaft 59 mounted at the end of the rod 28 and carrying a sprocket 82.  The rod 28 is slidable at its other end in a bearing 29 secured to the shaft 31 and accommodating the other hollow shaft 48 which also extends through the shaft 31.  The rod 28 is caused to move in the direction of its length by a cable 44 attached to its far end and passing round sheaves 45, 46 and through the hollow shaft 48. The arm 58 is rotated by rotation of the sprocket 82 caused by a chain 85 conecting it to a double sprocket 78 which is again connected by a chain 84 to a sprocket 77 on the end of the shaft 48 which is rotated by chain drive on a sprocket 86 at its other end.  The double sprocket 78 is supported by arms 70, 72 to maintain centre distances upon linear and pivotal movements of the rod 28.  The arm 36, sprocket 86, cable 44 and air cylinder 61 are controlled by a series of cams as below, which are shaped to give a complex movement to the arm 58 which dips the form 15 through the latex tank in a path as shown in Fig. 10, entering toe first and leaving last to give an even thickness of latex.  At the end of this movement the other arm assembly 27 of which the components are the same as those of the arm 26 but which forms a mirror image of that assembly, grips the dipped article and dips it through the coagulant in the tank 14, Fig. 10, and deposits it on platforms 173, 174, 175, 176, Fig. 5, similar to the platforms 168-171.  As the conveyer 22 rises, the next cross-bar 19 carried by it picks up the rod 16 and carries the forms with the rubber articles on them to a drying room.  Cam control.  On a shaft 40, coupled to one end of the output shaft 41, Fig. 5, are mounted cams 39, 92 and 57 which operate the arm 36, sprocket 86 and cable 44 respectively of the arm assembly 26; three other cams on the same shaft 40 operate the corresponding members of the arm assembly 27.  The cam 39 is in contact with a cam follower 38 on the arm 36, Fig. 4.  The cam 92 is in contact with a cam follower 91 on a lever arm 90 to the end of which a chain 87 is connected, through a link 89, which passes over the sprocket 86 and is tensioned by a weight 83.  The cam 57 is in contact with a cam follower 56 on a lever arm 53 to the end of which the cable 44 is attached.  The shaft 40 carrying the cams is mounted on a separate carriage 132, Fig. 11, on castors 1321 so that the cams as a unit may easily be removed and replaced by a different set of cams mounted on a similar carriage. The shaft 40 is held in a self aligning bearing 133 at the outer end and the inner end is unjournalled but surrounded by a guard strap 134; by these means keys 136, 137 projecting from the end of the shaft easily enter corresponding recesses in the end of the output shaft (which is also tapered to enter a recess in the end of the shaft 40) when the carriage 132 is wheeled into place, where it is locked by moving a lever 151 and so rotating a shaft 148, Fig. 4 and 5, to which arms 146, 147 are fixed which hold the carriage in place by engaging behind brackets 152, 153 secured to its front.  The air cylinder 61, and the corresponding air cylinder in the arm assembly 27, are operated by cams on an extension 411 from the output shaft 41, Figs. 5 and 16. Considering the cylinder 61, compressed air is supplied to, or exhausted from it through the flexible pipe 67, the bore of the hollow shaft 59 and a flexible pipe 68 connected to a slide valve 180.  The slide 185 of this valve is operated by two bell cranks 187, 188 controlled by a cam 198 and another cam (not shown) on the shaft 411.  When the tip 196 of the lever 187 drops into a notch 201 in the periphery of the cam 198 the crank 187 pivots to shift the slide 185 in the position to connect the pipe 68 to exhaust, as in Fig. 16. The tips of the bell crank arms and the notches in the cams are shaped so that the tips enter the notches instantaneously, and the opening 193 in the block 194 to which the slide 185 is joined is wider than the ends of the bell cranks, and the result is that the movement of the slide is always rapid and it is impossible for it to stop in a partly open or closed position.  The other air cylinder is cam-controlled in a similar manner.  The same conveyer may be used to convey the form to and from one or more dipping machines and through one or more drying ovens or leaching chambers.  It is stated that the apparatus may be used for other operations where it is desired to move an article in a predetermined path to required positions, e.g. for spraying, embossing or affixing labels.