Patent GB-971258-A (GB)
Title: Improvements in or relating to the manufacture of wheels
IPC: B60B3/06
Filed: 1960-11-01
Abstract: 971,258. Making vehicle wheels; extruding; forging; stamping; rolling; working at specified temperatures. REYNOLDS METALS CO. Nov. 1, 1960 [Nov. 9, 1959; Jan. 18, 1960; Aug. 5, 1960], No. 37548/60. Headings B3A, B3H, B3M, B3P, B3Q and B3V. [Also in Division B7] An automobile wheel comprises a web 502 integral with annular rim portions 508, 510 forming the tyre well 498, and integral radial ribs 500, 504 extending along the outside of at least one rim portion. The wheel is made of cast or preferably wrought aluminium alloy by hot extrusion pressing and rolling followed by quenching and tempering. Holes 512 are provided for circulation of cooling air to the hub and brake drum assembly 472 to which the wheel is secured by bolts 478 and located by pin 486. Asbestos rings 912, 914, Fig. 29, may be provided to insulate the hub 472 and wheel web 502 from the heat produced in the brake drum 522. The hub 472 may be of cold worked aluminium alloy, malleable iron or forged steel. A hub cap 924 of aluminium alloy made by hot impact extrusion and chemically brightened and anodized, is secured to the wheel by spring clips 926. Other shapes of wheel are described, Figs. 3, 4, 31 (not shown). Extruding; forging.-The wheel is made from a starting blank 526, Fig. 6, of wrought aluminium alloy heated to 980-990‹ F. in an electric induction heater or in a furnace with a recirculating atmosphere, and then soaked in an atmosphere of air and ammonium fluoroborate to give a bright surface finish. In another embodiment, Figs. 32-36 (not shown), the starting blanks are formed from a continuous casting which is severed into blanks by a multiple saw. The blanks are hot forged and upset and then hot or cold shaved to produce bright surfaces. Alternatively, the blanks may be cast singly and then hot or cold rolled. In a first pressing operation, Fig. 12, the blank is backwardly impact extruded in a die 636, which may be segmental, by means of a punch 628 which locates over a centering pin 618. Electric resistance heaters 640, 680 are provided. The resulting workpiece, 528, Figs. 7, 8 (not shown), has a thin wall 694 and radial ribs 688. During the upstroke of the punch the workpiece is removed from the die by raising the die bottom 612 with knock-out rods 630. A stripper 682 is also provided on the punch. The workpiece is then placed in a second die 718, Fig. 18, which may be segmental, and is forwardly extruded by punch 772 to form the wall 756 and radial ribs 750. Simultaneously, the upper radial ribs are thickened. Electric heaters 724, 780 are provided in the die and punch. During the subsequent upstroke, a central locating pin 738 is raised by rod 744 and an ejector sleeve 762 also is raised by rods 766, to remove the workpiece. A stripper member 784 is provided on the punch. In another embodiment, Fig. 37, the workpiece is extruded backwardly and forwardly simultaneously. Stamping.-The resulting hot workpiece, Figs. 9, 10 (not shown), is placed over a locating pin 832 on a base 820, Fig. 22, and pressed by a punch 850 against an enclosing outer die formed by segments 826 which are moved radially inwards during the initial downstroke of the punch by a cam surface 870 engaging surfaces 872 on the die segments. These are carried by a vertically movable platform 828 and guided radially by rods 880 having retraction springs 884, Fig. 23 (not shown). An air escape vent 871 is provided. The workpiece is ejected from the die by raising pin 832 and is removed from the punch by stripper member 860. The pressing operations may be performed in an hydraulic or cam-actuated press. Rolling.-The workpiece 498a, Fig. 28, is mounted between chucks 904 on a lathe and its rim is rolled by a die roll 902. The edges 508a, 510a may also be trimmed by cutting tools and beaded or rolled inwardly slightly at their extremities. The trimming and beading may be performed on the device 904 or on a separate device. The wheel is finally quenched in a spray, water or oil bath or air current and anodized. Working at specified temperatures.-The aluminium alloy is worked at 750-1100‹ F., preferably 980-990‹ F. Specification 971,259 is referred to.