GB1573358A - Core apparatus - Google Patents

Description

(54) CORE APPARATUS (71) We, CATERPILLAR TRACTOR CO., a corporation organized and existing under the laws of the State of California, United States of America, of 100 N.E.

Adams Street, Peoria, Illinois 61629, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a core, and more particularly to a portion of a core used in the formation of, for example, a tire.

The Specification of our U.K. Patent No.

1,463,847 discloses apparatus including a rigid mold body and an expandable bladder associated therewith, the bladder being inflatable and expandable for form a press a core between itself and the mold body. The core is made up of a portion comprising sand core material and a portion comprising an annular substantially inextensible rollrestraining hoop. The roll-restraining hoop as disclosed in the above patent Specification has, in cross-section, a rounded upper end. In the final core as formed, a side surface of the roll-restraining hoop defines a portion of the outer surface of the core.

In general, the roll-restraining hoop of the type disclosed in the above patent specification is made up of a first elastomeric annular part having substantially inextensible wires embedded therein, and a second annular part of elastomeric material secured to the first part. The elastomeric material making up the separate roll-restraining hoop portions is uncured and the two portions are jointed together as a unit to form the overall rollrestraining hoop. The hoop is then located within the upper portion of the mold, as described in that patent.

As is well known, all rubber materials, whether cured or uncured, tend to assume an original form when released from an applied stress. In the presently used system as disclosed in the above patent specification, a great degree of care must be exercised in the operation joining the roll-restraining hoop sections, to provide proper relative positioning of those portions. This is extremely important since one side of the rollrestraining hoop defines a portion of the outer surface of the core, and it is of great interest that this outer surface of the core be smooth and continuous throughout. The prior art configurations are not wholly satisfactory in this regard.

Therefore, according to the present invention a roll-restraining hoop for a tire and for use as part of a core in forming a tire, has an elongate cross-section one end of which has a recess formed therein.

Two annular members in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a sectional view of a portion of an overall core forming apparatus.

Figure 2 is an enlarged view of the area 11-11 of Figure 1.

Figure 3 and 4 are sectional views of the core formed by the apparatus of Figures 1 and 2, utilizing conventionally formed rollrestraining hoops; and Figures 5 and 6 show first and second embodiments of particular roll-restraining hoops which are the subject of this invention.

There is shown in FIG. 1, in accordance with the above mentioned U.K. specification, an annular roll-restraining hoop 10 supported by extendable and retractable fingers 12 on plungers 14 within the mold body 16 in close proximity thereto. The conventional roll-restraining hoop 10 is made up of a first annular member portion 18 of elastomeric material having wires 20 embedded therein, and a second elastomeric annular portion 22 secured thereto. It is to be seen that the roll-restraining hoop 10 defines in cross-section an end 24 of generally rounded configuration. As set forth above, in the joining of the roll-restraining hoop portions 18,22 it is possible that the end 24 of the portion 22 is caused to locate more to the left with respect to a vertical line in FIG. 1 than is desired.This results in a condition wherein, subsequent to the support of the rollrestraining hoop 10 by the fingers 14, but prior to the introduction of a mixture of sand and silica binder 26, the end 24 naturally adopts the position shown in FIG. 3. Upon introduction of sand and silica binder 26 into the area described above, and upon formation of the core 28, the overall core 28 will adopt the configuration shown in FIG. 3. It will be seen that the outer surface 30 thereof is not smooth and continuous in configuration as is desired for the formation of a tubetire on such outer surface.

Similarly, if the joining operation of the portions 18', 22' causes the portion 22 to be biased to the right as shown in FIG. 4, upon removal of the core 28' from the apparatus, the portion 22' will adopt the position shown in FIG. 4, again providing a discontinuous outer surface 30' of the core 28'. In either the case of FIG. 3 or FIG. 4, it will be seen that a certain amount of re-working of the core 28,28' is necessary to indeed provide the desired outer surface of that core.

Referring to FIG. 5, it will be seen again that the core 32 is made up of a core portion 34 and an annular member 36, generally as described above. In such apparatus, the annular roll-restraining hoop member 36 is made up of a first annular member portion 38 of elastomeric material having wires 40 embedded therein, and a second elastomeric annular member portion 42 secured thereto.

First portion 38 is substantially inextensible so that the overall annular member is substantially inextensible. As shown in the cross-section of the roll-restraining hoop, the second annular member portion defines in cross-section a depression 44, the end 46 actually being dove-tailed in configuration.

In the use of such roll-restraining hoop 36, it is positioned in the same manner as the one previously described, and then sand and silica binder is introduced in accordance with the above. The dove-tailed end 46 provides surfaces 48,50 which co-act with the core portion 34 formed of sand and silica binder, to provide positive and effective location of that end 46 relative to the core portion 34, so that the core portion 34 and the core portion made up of the roll-restraining hoop 36 together define a core 32 having a smooth outer surface 52 with a side surface 54 of the roll-restraining hoop 36 making up a portion of that outer surface 52 of the core 32.

In FIG. 6 is shown another embodiment of roll restraining hoop 60 in accordance with the present invention. As shown therein, the roll-restraining hoop 60 is made up of an annular member portion 62 of elastomeric material having wires 64 embedded therein, and a second annular member portion 66 of elastomeric material, the wires 64 rendering the overall roll-restraining hoop 60 to be substantially inextensible. In this embodiment, the end 68 defined by the rollrestraining hoop 60 in cross-section is generally stepped in configuration, with the depression 70 thereof being located in the end product closer to the outer surface 76 than the inner surface of the core 72.

Again, it will be seen that the rollrestraining hoop 60 is positioned in accordance with the FIG. 1 and 2 disclosure, and the particular configuration of the end 68 results in positive and effective location and holding of that end 68 in relation to the core portion 74 so that the overall core 72 formed defines a smooth outer surface 76 with a side surface 78 of the roll-restraining hoop 60 making up a portion of that outer surface 76 of the core 72.

WHAT WE CLAIM IS: 1. An annular roll-restraining hoop for a tyre, for mounting in a core defining the internal surface of the tyre and for subsequent incorporation into the tyre during the moulding process, the roll-restraining hoop having an elongate cross-section one end of which includes a recess formed therein.

2. A roll-restraining hoop according to claim 1, wherein the end of the cross-section has a substantially dove-tail shape.

3. A roll-restraining hoop according to claim 1, wherein the recess comprises a rabbet formed in the radially oute edge of the roll-restraining hoop.

4. A roll-restraining hoop according to any of claims 1 to 3, which comprises a first annular, substantially inextensible portion and a second elastomeric, annular portion in which the recess is formed.

5. A roll-restraining hoop according to claim 1, substantially as described with reference to Figure 5 or Figure 6 of the accompanying drawings.

6. Apparatus for use in making a tyre, the apparatus comprising an annular core which includes a roll-restraining hoop according to any of claims 1 to 5, the core having a generally radially extending annular surface provided in part by a side surface of the roll-restraining hoop.

7. Apparatus according to claim 6, substantially as described with reference to Figures 1 and 2 of the accompanying drawings when modified by Figure 5 or Figure 6.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. configuration. As set forth above, in the joining of the roll-restraining hoop portions 18,22 it is possible that the end 24 of the portion 22 is caused to locate more to the left with respect to a vertical line in FIG. 1 than is desired. This results in a condition wherein, subsequent to the support of the rollrestraining hoop 10 by the fingers 14, but prior to the introduction of a mixture of sand and silica binder 26, the end 24 naturally adopts the position shown in FIG. 3. Upon introduction of sand and silica binder 26 into the area described above, and upon formation of the core 28, the overall core 28 will adopt the configuration shown in FIG. 3.It will be seen that the outer surface 30 thereof is not smooth and continuous in configuration as is desired for the formation of a tubetire on such outer surface. Similarly, if the joining operation of the portions 18', 22' causes the portion 22 to be biased to the right as shown in FIG. 4, upon removal of the core 28' from the apparatus, the portion 22' will adopt the position shown in FIG. 4, again providing a discontinuous outer surface 30' of the core 28'. In either the case of FIG. 3 or FIG. 4, it will be seen that a certain amount of re-working of the core 28,28' is necessary to indeed provide the desired outer surface of that core. Referring to FIG. 5, it will be seen again that the core 32 is made up of a core portion 34 and an annular member 36, generally as described above. In such apparatus, the annular roll-restraining hoop member 36 is made up of a first annular member portion 38 of elastomeric material having wires 40 embedded therein, and a second elastomeric annular member portion 42 secured thereto. First portion 38 is substantially inextensible so that the overall annular member is substantially inextensible. As shown in the cross-section of the roll-restraining hoop, the second annular member portion defines in cross-section a depression 44, the end 46 actually being dove-tailed in configuration. In the use of such roll-restraining hoop 36, it is positioned in the same manner as the one previously described, and then sand and silica binder is introduced in accordance with the above. The dove-tailed end 46 provides surfaces 48,50 which co-act with the core portion 34 formed of sand and silica binder, to provide positive and effective location of that end 46 relative to the core portion 34, so that the core portion 34 and the core portion made up of the roll-restraining hoop 36 together define a core 32 having a smooth outer surface 52 with a side surface 54 of the roll-restraining hoop 36 making up a portion of that outer surface 52 of the core 32. In FIG. 6 is shown another embodiment of roll restraining hoop 60 in accordance with the present invention. As shown therein, the roll-restraining hoop 60 is made up of an annular member portion 62 of elastomeric material having wires 64 embedded therein, and a second annular member portion 66 of elastomeric material, the wires 64 rendering the overall roll-restraining hoop 60 to be substantially inextensible. In this embodiment, the end 68 defined by the rollrestraining hoop 60 in cross-section is generally stepped in configuration, with the depression 70 thereof being located in the end product closer to the outer surface 76 than the inner surface of the core 72. Again, it will be seen that the rollrestraining hoop 60 is positioned in accordance with the FIG. 1 and 2 disclosure, and the particular configuration of the end 68 results in positive and effective location and holding of that end 68 in relation to the core portion 74 so that the overall core 72 formed defines a smooth outer surface 76 with a side surface 78 of the roll-restraining hoop 60 making up a portion of that outer surface 76 of the core 72. WHAT WE CLAIM IS:

1. An annular roll-restraining hoop for a tyre, for mounting in a core defining the internal surface of the tyre and for subsequent incorporation into the tyre during the moulding process, the roll-restraining hoop having an elongate cross-section one end of which includes a recess formed therein.

2. A roll-restraining hoop according to claim 1, wherein the end of the cross-section has a substantially dove-tail shape.

3. A roll-restraining hoop according to claim 1, wherein the recess comprises a rabbet formed in the radially oute edge of the roll-restraining hoop.

4. A roll-restraining hoop according to any of claims 1 to 3, which comprises a first annular, substantially inextensible portion and a second elastomeric, annular portion in which the recess is formed.

5. A roll-restraining hoop according to claim 1, substantially as described with reference to Figure 5 or Figure 6 of the accompanying drawings.

6. Apparatus for use in making a tyre, the apparatus comprising an annular core which includes a roll-restraining hoop according to any of claims 1 to 5, the core having a generally radially extending annular surface provided in part by a side surface of the roll-restraining hoop.

7. Apparatus according to claim 6, substantially as described with reference to Figures 1 and 2 of the accompanying drawings when modified by Figure 5 or Figure 6.