MULTI-SIZE TIRE CHUCK

Abstract: A tire chuck comprises two opposing frusto-conical members (24 and 25) each having a plurality of stepped ridges so as to accommodate a range of sizes of a tire (30), the members (24 and 25) being constructed of a material which is deformable and is relatively transparent to, and not degraded by x-rays. The chuck can be combined with an x-ray source (40) and an x-ray receiving device to permit x-ray inspection of a tire (30) mounted on the chuck.

Description: The invention relates to a device for holding a pneumatic tire under internal inflation pressure, comprising two opposing frusto-conical members having a plurality of stepped ridges shaped to fit the axially outer portion of a tire bead and sized to accomodate a plurality of standard bead diameters, said frusto-conical members extend from rigid hub members adapted for rotation. In this device a tire can be subjected to any of a variety of operations, such as inspection, balancing, grinding and the like, while the tire is held under pressure. A number of chucking devices have been developed in the past which were designed to hold a tire for inspection or some other operation. Some of these devices are capable of accepting only a single size tire, and differing hubs must be mounted when different size tires are to be inspected. US-A-3 801 786 discloses a tire inspection system for x-raying tires employing tire enganging members each having bead rim engaging hubs. Each hub includes in turn a support collar, projecting from each hub. The hub-and-collar combination defines a sealing area which engages the bead rim of a tire and establishes a fluid-tight seal to allow inflation of the tire. To accomodate tires of varying bead diameters, US-A-3 801 786 provides rigid separate bead rim adapters which must be manually attached to the rim-engaging hubs. US-A-3 801 786 further discloses an imaging system including an x-ray housing carrying a rotatable x-ray tube and re-ceiving unit. A rack-and-gear assembly supports the x-ray tube which may be rotated by a reversible electric motor and associated gear train. A significant aspect is that US-A-3 801 786 specifically suggests the desirability of having the hubs or the rim portions of the hubs constructed of materials substantially transparent to x-rays, including aluminum or certain plastic materials which are usable without deformation thereof i.e. which are non-deformable rigid members. To avoid separate bead rim adapters US-A-3 728 542 uses stepped opposing chuck members, which accept different tire sizes. The members, however, are rigid metal, incapable of flexure and opaque to x-rays. Furthermore, a device of the type mentioned in the beginning is known from US-A-3 550 443. Although this device has two opposing frusto-conical members with a plurality of stepped ridges shaped to accommodate a plurality of bead diameters it has the same limitations as the device according to US-A-3 728 542 i.e. the opposing members are rigid metal, incapable of flexure and opaque to x-rays. Finally US-A-3 948 094 discloses a similar tire chuck device in which a tire is held between flat surfaces of two opposing frusto-conical members for inspection during inflation. The flat surfaces are rigid metal plates, with a rubber covering for air-tight sealing between the tire beads and the rigid metal members. According to the present invention there is provided a device of the type mentioned in the beginning which is characterized in that said two opposing frusto-conical members are (a) a deformable, semi-rigid material, (b) a material which is relatively transparent to and not easily degraded by x-rays, and (c) retained by said rigid hub members. The members preferably have a substantially constant thickness through the series of stepped ridges so as to present a relatively constant mass when x-rays are passed therethrough, and also to provide the degree of flexibility desired when inflation pressure in a tire mounted thereon exerts axially outward pressure in the bead area. A more complete understanding of the invention may be obtained by reference to the drawings, which illustrate preferred embodiments of the invention. Fig. 1 is a cross-section of one of the members. Fig. 2 is a partially sectioned view of the device held in position with a tire mounted thereon. Fig. 3 is a partially sectioned view of the device without a tire mounted thereon. Referring to Fig. 1, a cross-section of one member is shown, indicated generally 1, with tire bead receiving ridges indicated 2, 3, 4, 5, 6, 7 which are shaped to conform to the axially outer portions of the beads of tires (not shown) of progressively larger radial diameter and progressively larger axial separation. A lobe 8 is located at the radially centermost portion of the member, shaped to be gripped and held by a hub member (not shown). Relieved portions 9, 10, 11, 12 and 13 of the member are located with respect to the ridges and opposite thereto so as to give the tire-receiving portions of the member a relatively constant cross section thickness. It will be seen that the geometry of the member 1 is such that axially outward pressure by the bead of a tire (when mounted thereon under internal inflation pressure) will tend to deflect the member axially away from the bead, but the frusto-conical shape of the member also acts to counter such deflection, the radially outer portions of the member then being in compression. Referring to Fig. 2, a preferred device is shown, in which opposing hub members 20 and 21 are shown mounted for rotation, respectively, on hollow shafts 22 and 23. Shafts 22 and 23 are held on their opposite ends by frame members (not shown) with associated bearings and drive mechanism, also not shown. Members 24 and 25 are shown, held by gripping portions 26 and 27 of hub members 20 and 21, the gripping portions 26 and 27 being disposed about the lobes 28 and 29 of the respective members 24 and 25. A pneumatic tire 30 is shown held between the outer portions of members 24 and 25, with the bead portions 31, 32 of tire 30 in sealing contact with stepped ridges 33 and 34 of members 25 and 24 respectively. Internal air pressure can be introduced through the hollow central portions of either of the hubs and shafts. Shaft 35 is concentric with, and inside shaft 22. Shaft 35 supports member 36, which, in turn contains a rack- and pinion support for an x-ray source. The rack 37 extends slidably through member 36 and is extended and retracted by the rotation of pinion 38, which is actuated by shaft 39, extending back through the center of shaft 35. X-ray source 40 is mounted on end of rack 37, shown in Fig. 2 in its fully extended position. Power is supplied to source 40 through connector 41. In its fully outward position, source 40 can direct x-ray radiation outward through any portion of the tire, from bead to bead, to a receiving mechanism located outside the tire (not shown). The tire and the x-ray devices can be rotated relative to one another, so that complete inspection of the tire can be accomplished in a single rotation, if desired. Since the members are relatively transparent to x-rays, no difficulty is experienced, even in the bead areas, in obtaining an accurate x-ray picture of the tire construction. Fig. 3 shows the preferred embodiment of the device, with no tire mounted thereon, and with the members axially separated from their positions in Fig. 2. In this view, rack 37 has been moved radially upward through member 36, so that rack 37 and x-ray source 40 are radially within the plane of the radially innermost ridges of members 24 and 25, enabling a tire to be mounted and demounted. It should be understood that although the members are shown, as in Figs. 2 and 3, mounted in a device for x-ray inspection of a tire, the members can be used to hold a tire under inflation pressure for any other desired purpose, such as balancing, or examination by other means. In a more preferred embodiment of the invention, the members are formed from a material which combines optimum properties of density, hardness, x-ray transparency and resistance to the degrading effect of x-rays. It has been found that a particular combination of a density of from 1.15 to 1.25, a hardness of from 40 to 72 (Shore D) and good resistance to x-rays is realized in certain thermoplastic polyester elastomers, including such materials sold by E. I. du Pont de Nemours & Company under the trademark "Hytrel." Other materials which have the required properties, as stated above, are also acceptable, as well, for the composition of the members.

Claims: A device for holding a pneumatic tire (30) under internal inflation pressure, comprising two opposing frusto-conical members (24, 25) having a plurality of stepped ridges (2 to 7) shaped to fit the axially outer portion (31, 32) of a tire bead and sized to accomodate a plurality of standard bead diameters, said frusto-conical members (24, 25) extend from rigid hub members (20, 21) adapted for rotation, characterized in that said two opposing frusto-conical members (24, 25) are (a) a deformable, semi-rigid material, (b) a material which is relatively transparent to and not easily degraded by x-rays, and (c) retained by said rigid hub members (20, 21). The device of claim 1, characterized in that members (24, 25) have a substantially constant thickness through the area of the stepped ridges (1-13). The device of claim 1, characterized in that said members (24, 25) are made from a deformable, semi-rigid material having a density of from 1.15 to 1.25 and a Shore D hardness of from 40 to 72. The device of claim 3, characterized in that said members (24, 25) are made from an elastomeric thermoplastic polyester. The device of claim 1, characterized in that said members (24, 25) have lobe portions (28, 29) engaged by gripping portions (26, 27) of said hub members (20, 21) for holding said members (24, 25) in a spaced, opposing position relative to each other. The device of claim 1 characterized in that means for x-ray inspection of a tire (30) is mounted between said members (24, 25) and comprises an x-ray source (40) supported for rotation within said hub members (20, 21) in a path having a diameter substantially that of said two opposing frusto-conical members (24, 25).

Inventors: FLORY, THOMAS ABRAHAM
Applicants: PENN VIDEO, INC.
Application year: 1986
Main classification: G01N23
IPC codes: G01B15, G01M17, G01N23