October 1, 19J0. 



THE INDIA RUBBER WORLD 



33 



the rubber sheets closely into contact therewith. The table is 

 then lowered, leaving its sheet held to the under side of the 

 vacuum plate, which is moved to the position shown in Fig. 1, 

 directly between the forming molds. 



.\ valve is operated to apply hydraulic pressure to the plunger, 

 raising the lower forming mold E into contact with the rubber 



F.G 1 





Fig. 2 



Fig 4 



Roberts' Tube Molding .^nd Vulcanizinc .\pp.\ratus 



at the under side of the plate .\, and the raising movement is 

 continued, carrying the plate upwardly, bringing the upper sheet 

 into contact with the upper mold F. Here the movement of 

 the platen is stopped, the valve D is operated to relieve the 

 vacuum in the plate, and a valve controlling the vacuum tubes 

 G is opened, drawing the air from the mold cavities and from 

 the groove H shown in Fig. 2, securely holding the sheets to 

 the mold members. 



The platen is then lowered and the vacuum plate withdrawn, 

 leaving the sheets held to the molds by vacuum. This plate 

 is then moved to the position shown in Fig. 3, and the rubber 

 sheets are again placed upon this plate on the table B while the 

 forming operation is continued in the press. 



The application of vacuum to the mold is continued until the 

 rubber sheets are stretched tightly into the cavities, when the 

 platens are brought together until the cutting edges meet, sever- 

 ing the rubber within the mold cavities thus forming a sub- 

 stantially flat ring comprising two annular members having 

 their edges pinched together by the bevel surfaces of the cutting 

 edges, and thus caused to adhere. Upon separating the forming 

 molds the tube is then removed and placed in a vulcanizing 

 mold. 



In making inner tubes for pneumatic tires, it is desirable to 

 secure the valve stem between the meeting edges of the rubber 

 ring severed from the sheets, so that when a tube thus formed 

 is vulcanized it may be complete. Accordingly the cutting edge is 

 looped inwardly as indicated at I in Fig. 3 and within this loop 

 a cavity is provided into which the rubber is drawn by the 

 suction, so that before bringing the forming molds together to 

 sever the sheets the valve stem may be laid on rubber in the 

 lower mold in this cavity, with its head in the concave portion 

 of the trough. When the mold members are brought together 

 and severed, the rubber is caused to lie closely about the shank 

 of the valve stem and the sheets are severed entirely around the 

 stem by the edges. 



Tlic vulcanizing mold illustrated in Fig. 4 preferably comprises 

 two trough-shaped members formed of pressed metal having 

 convex portions complementary to the convex portions of the 

 tube, while at the sides the cavity extends inwardly in concave 

 form, fitting the concave sides of the tube. Flanges provide for 

 securiim the mold members together by bolts or clamps. .Xt 



one point these flanges are bowed outwardly to surround the 

 valve stem and press the rubber into contact therewith, while 

 the remaining portion of the rubber surrounding the shank may 

 be trimmed off at the inner sides of the flanges before vulcaniza- 

 tion. A considerable number of tubes carried in such molds are 

 inflated therein, pressing the walls of the tube tightly to the 

 inner surfaces of the mold. These are then placed in a vul- 

 canizing chamber and cured. (Fred T. Roberts, Cleveland Heights, 

 Ohio, assignor to Paramount Rubber Consolidated, Inc., Phila- 

 delphia, Pennsylvania. United States patent No. 1,346,848). 



MACHINE FOR FORMING BATTERY JARS 



The operation of this apparatus is started with the wrapping 

 box A opened out flat, as shown in Fig. 2 and the mandrel 

 liijldcr B ti'.rned up from the posilii.n represented in the draw- 

 1 igs, so that a core C will occupy an inverled vertical position. 

 In this position, the 

 pieces of raw stock 

 for forming t h e 

 lugs may be in- 

 serted in their 

 grooves, and t h e 

 bottom - forming 

 sheet accurately 

 laid on the end of 

 t h e mandrel. A 

 side-forming sheet 

 cut to the proper 

 size is laid on the 

 opened-out box and 

 properly registered 

 with the edges 

 thereof, its bottom 

 edge being slightly 

 overlapped upon the 

 edge-turning plates. 

 The holder and 

 mandrel are then 

 swung down into 



horizontal operative „ 



, ., Battery jar Machine 



position, and the ■' 



plunger D is advanced until its presser-plate rests against the 

 work to hold the bottom sheet in place as shown in Fig. 1, the 

 weight of the lever E keeping the parts in this position while 

 the side wrapping is performed. Then the free sections of the 

 wrapping box, carrying with them the super-imposed portions 

 of the side-forming sheet, are closed upon the mandrel. First, 

 the two wider side sections are swung ujiwardly into position, 

 and then the third section is turned over on the upper side 

 of the mandrel and clamped by a cam lever which produces 

 pressure on the work. The final step in the side-folding opera- 

 tion consists in turning the fourth folder section and its cor- 

 responding sheet portion over on the upper face of the mandrel 

 by means of the handle F and applying pressure to the side 

 seam formed by the overlapping skived edges of the rubber 

 sheet. The wrapping action is progressive and avoids the en- 

 trapping of air. The final closing movement of the fourth section 

 causes a shearing action which trims off the excess of material 

 on the outer side of the seam. 



By pressure on the hand-lever £ the plunger compresses and 

 embosses the bottom sheet and consolidates it witli the lugs while 

 the seam-pressing plates on the plunger compress the in- 

 wardly-turned edges of the side sheet and perfect the bottom 

 seams. The wrapping box is then undamped and opened out, 

 and the mandrel with the formed jar thereon, is swung upwardly 

 into vertical position. It may then be removed by sliding it from 

 the holder and the jar vulcanized in the usual manner while 

 still on the mandrel, .\nnthcr mandrel is then substituted and 



