GB2094217A

GB2094217A - Method and apparatus for action moulding solid steel-banded press-on industrial rubber tyres

Info

Publication number: GB2094217A
Application number: GB8106880A
Authority: GB
Original assignee: Teledyne Industries Inc
Current assignee: TDY Industries LLC
Priority date: 1981-03-05
Filing date: 1981-03-05
Publication date: 1982-09-15

Abstract

A method of and apparatus for action moulding solid steel-banded industrial rubber tyres wherein a steel band (111) is inserted in the cavity of a bottom mould member (3) when the top mould member (2) is in the open position. Bite ring (20) and tyre knock- out member components (19) are contained in mould member cavity recesses. Closing movement of the mould members to mated position seals the bite ring (20) and knockout member components (19) against the steel band (111) and mould member recess surfaces to prevent leakage of injected rubber compound from the cavity during injection and curing. The mould (1) has an internal wedge member (48) which expands a split ring (56) against the steel band (111) when the mould is closed to prevent band distortion during the injection and the rubber is cured therein to form the tyre tread portion which is bonded to the steel band (111) during curing. Mould components knock the cured tyre out of the top mould member (2) upon opening the mould (1). The rubber compound is injected into the mould cavity under pressure at the curing temperature of the compound and this temperatures maintained during curing. <IMAGE>

Description

SPECIFICATION Method and apparatus for injection moulding solid steel-banded press-on industrial rubbertyres The invention relates to solid industrial rubber tyres and to the manufacture thereof. More particularly the invention relates to new methods and apparatus for manufacturing such tyres using injection moulding technology whereby unvulcanized rubber compound is injected into a mould cavity surrounding a steel band to which the rubber is bonded during vulcanizing to form a solid press-on industrial rubber tyre.Further, the invention involves new mould constructions and moulding procedures which permit vulcanizing the injected rubber compound and bonding thereof to a steel band in an extremely short period of time without steel band distortion from extremely high injection moulding pressures required during injection, moulding and vulcanizing, which results in finished products having very favourable characteristics.

The manufacture of solid industrial steel-banded rubber'tyres heretofore has been carried out using compression moulding procedures, techniques and equipment. Such compression moulding procedures usually have required a two to three-hour cycle per tyre for carrying out moulding, vulcanizing and related operations to form a finished product.

These compression moulding operations include individually applying a predetermined quantity of unvulcanized rubber compound to and around a steel band, inserting such rubber-compoundsurrounded band into an open mould cavity, closing the mould, locating the mould under compression in various known types of heating equipment, and heating the mould to vulcanize the rubber and bond it to the steel band. A relatively large loss of rubber in the flash formed between mould components results in carrying out such compression moulding operations. This rubber loss occurs because the predetermined amount of rubber compound applied to and around the steel band before mould cavity insertion must be sufficient to assure by overfill or overflow that the mould cavity is completely filled with rubber when closed and heated under pressure.

Compression moulding procedures have been used for the manufacture of bushings consisting of inner and outer spaced metal sleeves or shells with an intervening annular rubber body vulcanized and bonded to and between the metal sleeves such as shown in Lord U.S. Patent No.2,187,165. These bushings are moulded by axially pressing end caps toward each other to confine the rubber body under pressure during vulcanizing. The end caps engage the ends of the spaced sleeves and also impart compression forces during moulding to unvulcanized rubber compound located between the sleeves. Excess rubber overflows from the rubber body between the sleeves into an overflow space. A thick-walled metal pressure tube surrounds a thin outer bushing sleeve during moulding to prevent bulging of a thin sleeve from the pressure maintained on the rubber during vulcanization.Such compression moulding procedure for the manufacture of such bushings involves many of the same disadvantages described above concerning the com pression moulding of solid industrial steel-banded rubber tyres.

Some of these problems related to compression moulding of bushings were sought to be solved by the injection moulding of torsion springs or bushings set forth in the Krotz U.S. Patent No.2,724,864 wherein the inner and outer metal sleeves or bands have substantial radial thickness and are engaged at their ends by annular sealing projections carried by the upper and lower mould members which bite into the ends of the metal sleeves when the mould is closed to seal the joints thus formed against seepage of rubber compound injected into the space between the sleeves. The filled mould after injection is then transferred and held under pressure between heated plates of a vulcanizing or curing press.However, during injection and vulcanizing there is nothing in Krotz to prevent distortion of the inner sleeve from the pressure developed during injection of the unvulcanized rubber compound into the annular cavity between the inner and outer sleeves. Further, in the Krotz procedure, after the mould has been closed and injected, when it is transferred to the curing press there is nothing to maintain injection pressure on the injected rubber in the space between the sleeves during vulcanization. Thus the Krotz curing step is essentially a compression moulding step.

Insofar as we are aware, there have been no solid industrial steel-banded rubbertyres produced by complete injection moulding procedures before the first production thereof in accordance with the invention. Thus, an injection moulded steel banded industrial rubbertyre has been unknown in the art prior to our invention; and there has been a want existing in the art for procedures and equipment by which an injection moulded steel-banded industrial rubbertyre could be produced with the attendant advantages of injection moulding including high quality finished products and short curing times.

Objectives of the invention include providing a new mould construction which enables the use and advantages of injection moulding procedures to manufacture moulded steel-banded solid industrial rubbertyres; providing such new mould construction in which meeting, mating or parting faces or surfaces of mould plate members and their components, which communicate with the mould cavity portions defined in part by a steel band inserted in the cavity, are held under pressure-sealing relation when the mould is closed to prevent leakage between said sealed faces or surfaces of rubber compound injected under high pressure into the mould cavity; providing such new mould construction in which relatively movable wedge members are expanded internally of the steel tyre band to prevent inward distortion of the steel band during injection moulding of the steel-banded tyre; providing such new mould construction with bite ring components, one of which is biased toward the other and which bite rings are relatively movable with respect to each other during mould closing and opening, and which co-operate with other mould plate member components to achieve the described sealing, and to knock the tyre out of the top mould cavity portion during mould opening and to release the expanded wedge member engagement with the interior of the steel tyre band during opening of the mould; providing procedures of mould plate member control to achieve the stated advantages; providing mould structures and moulding procedures which produce high quality characteristics in steel bandsed injection moulded solid industrial rubber tyres; providing a new steel-banded injection moulded solid industrial rubber tyre mould constructiqn which incorporates the foregoing objectives in a co-ordinated, inter-related and cooperative relationship of the described components; and providing such new mould construction which achieves stated objectives in a most efficient and readily operated manner, eliminates difficulties and solves long standing problems and satisfies needs that have existed for many years in the art of manufacture of steel-banded solid industrial rubber tyres.

These and other objectives and advantages may be obtained by the new constructions and use procedures of moulds for injection moulding solid steel-banded industrial rubber tyres, the general nature of which may be stated as including mating first and second mould plate members defining with a steel band inserted between the plate members a rubber tread-forming cavity surrounding the band when the plate members are mated under pressure; a hardened steel bite ring located within a recess formed in the first mould plate member adjacent the tread-forming cavity portion therein; the bite ring being movable in its recess and having a conical circumferential surface seated under sealing pressure in a complementary conical portion of the first mould plate member recess when the mould plate members are mated; the bite ring having a V-shaped annular projection-wedge seated, by band metal deformation when the plate members are pressure mated, in one end of the steel band insert which defines a portion of said cavity; said bite ring being mounted on a first knockout member movably mounted on the first mould plate; said first knockout member being biased toward the second mould plate member when the mould is closed; the moulded steel-banded tyre being knocked out by the biased first knockout memberfrcm the first plate member cavity portion upon opening the mould; means for injecting rubber compound into and for extracting gases from said cavity; and radially expansible means operative on closing the mould to internally engage a steel band insert and hold it against distortion from high injection pressure during rubber injection and during curing of injected rubber in said cavity.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic view of the first or injection station of known multi-station rubber injection moulding equipment wherein the improved moulds are used and the improved moulding steps are carried out to mould solid industrial rubbertyres, showing a mould carrier in onen position; Figure 2 is a diagrammatic view similar to Figure 1, showing mould plate sections closed and locked in a mould carrier at the injection station of Figure 1; Figure 3 is a view similar to Figures 1 and 2 illustrating rubber compound injection mechanism in position to inject the rubber into a closed and locked mould on a mould carrier at the injection station;; Figure 4 is a view similar to portions of Figures 1,2 and 3 showing a mould carrier at a final or eighth demoulding station with the mould open and the bottom mould plate withdrawn from the mould carrier, and deposited on a mould service table for removal of a moulded tyre from the bottom mould plate; Figure 5 is a diagrammatic top plan view of the equipment shown in Figure 1; Figure 6 is a diagrammatic top plan view of known multi-station rubber injection equipment including the injection and demoulding stations of Figures 1 and 4; Figure 7 is a side elevation of the new top and bottom mould plates closed and removed from a mould carrier; Figure 8 is an end view, looking in the direction of the arrows 8-8 of Figure 7, illustrating the closed mould; Figure 9 is a top plan view of the mould shown in Figures 7 and 8;; Figure 10 is a bottom plan view of the mould shown in Figures 7 and 8; Figure 11 is a somewhate diagrammatic view with a moulded tyre omitted, looking down on a bottom mould plate resting on a revoling mould carrier table at the demoulding station shown in Figure 6, the bottom mould plate being in position to be transferred from the revolving table to the mould service table; Figure 12 is a diagrammatic side elevation of a bottom mould plate being transferred at the demoulding station from the mould carrier table to the mould service table, illustrating a moulded tyre in the bottom mould plate; Figure 13 is a diagrammatic view similarto Figure 12, showing the bottom mould plate located on the mould service table, and the moulded tyre knocked out of the mould; ; Figure 14 is a fragmentary end elevation of the bottom mould plate located in its transfer guideways on the service table looking in the direction of arrows 14-14, Figure 13; Figure 15 is an enlarged bottom plan view of the top mould plate detached from the mould carrier; Figure 16 is an enlarged top plan view of the bottom mould plate detached from the mould carrier; Figure 17 is an end view of the bottom mould plate located in its transfer guideways on the revolving mould carrier table, looking in the direction of the arrows 17-17, Figure 11; Figure 18 is an enlarged fragmentary sectional view of top and bottom mould plates and related components mounted in a mould carrier and in a partially closed state while being closed after a steel band has been positioned in the mould cavity of the bottom mould plate;; Figure 19 is a fragmentary view similar to Figure 18, showing the position of the mould components after further closing movement of the top mould plate toward closed position; Figure 20 is a fragmentary view similar to a portion of Figure 19, showing the top mould plate nearly closed with respect to the bottom mould plate; Figure 2 1 is a view similar to Figure 20 showing the mould plates completely closed, and as locked in a mould carrier at the injection station (Figure 3) of the multi-station unit illustrated in Figure 6; Figure 22 is a sectional view of the locked mould in the mould-closed position of Figure 21, after rubber compound has been injected into the mould cavity at the injection station (Figure 3) of the equipment shown in Figure 6;; Figure 23 is an enlarged fragmentary sectional view of the relative position of the components at the top right-hand corner of the mould cavity as shown in Figure 22; Figure 24 is a view similar to Figure 23 illustrating the relative position of the components at the bottom right-hand corner of the mould cavity as shown in Figure 22; Figure 25 is a fragmentary sectional view similar to a portion of Figure 22 after the moulded tyre has been cured and separation of the top mould plate by upward movement thereof has just commenced which releases the tyre from the portion of the mould cavity in the top mould plate; Figure 26 is a view similar to Figure 25 after further opening of the mould during further upward movement of the top mould plate, showing release of mould components from expanded radial clamping engagement with the cylindrical interior of the bonded steel band of the tyre;; Figure 27 is a fragmentary horizontal sectional view of the knockout pin in the bottom mould plate taken on the line 27-27, Figure 18; Figure 28 is a vertical sectional view looking in the direction of the arrows 28-28, Figure 13, showing a moulded and cured tyre removed from the cavity portion of the bottom mould plate at the demoulding station; Figure 29 is a fragmentary section taken on the line 29-29, Figure 9; Figure 30 is an enlarged fragmentary section showing the injection gate in the closed mould taken on the line 30-30, Figure 9; Figure 31 is an enlarged fragmentary section showing the vacuum gate in the closed mould taken on the line 31-31, Figure 9; and Figures 32 and 33 are views similar to Figure 22 showing two modified forms of bottom mould plate.

Similar numerals refer to similar parts throughout the various figures of the drawings.

The new mould construction for injection moulding solid steel-banded rubber tyres is designed to utilize the many advantageous features of injection moulding technology. The new moulds indicated generally at 1 are adapted to be used in known multi-station rubber injection moulding machines.

Such machines may have as many as two to ten or more stations. One type of such machines is an eight station machine sold by Desma-Werke, GMBN., of 2807 Achim Desmastrasse 112, P.O. Box 140, near Bremen, West Germany.

Components of such a moulding machine, including an injection unit, a revolving table and mould carriers at each station on the table. For example, eight stations are illustrated diagrammatically in Figures 1 to 6. The general construction and Qperation of such Desma multi-station moulding machines forms no part of our invention. It is necessary, however, to refer to such machines in describing the improved mould construction and method of moulding carried out with the use of such moulds to enable injection moulding of solid steelbanded industrial rubbertyres.

Accordingly, the construction and use of the new industrial tyre moulds will be described first, followed by a description of the manner in which the moulds are used on multi-station injection moulding machines to produce injection moulded, steelbanded tyres.

The mould 1 (Figures 7 to 10) includes a top mould plate member 2 and a bottom mould plate member 3, each of which contains one-half of the mould cavity, the top cavity half being indicated at 4 and the bottom cavity half being indicated at 5, thereby forming a mould cavity 4-5 when the plates are mated and when the mould is closed.

The bottom mould plate 3 is formed with transfer guide slots 6. A plurality of spaced rollers 7 are mounted in the bottom face 7a of the bottom mould plate 3 along each lower corner below the transfer guide slots 6 for a purpose to be described below.

A round T-head 8 is mounted on the front end (right end viewing Figure 7) of the bottom mould plate 3 for releasable engagement or coupling with a transfer device to be described. A centrally located longitudinally extending slot 9 is formed in the bottom face of the main body of the bottom mould plate (Figure 10) extending from the front end 10 of the mould plate 3 to beyond the centre of the bottom mould plate cavity portion 5.

Three dowels 11 are mounted on the top mould plate 2 and project downward from the top plate 2.

When the top plate 2 is in open position above the bottom plate and is moved down as shown in Figure 18, the dowels are received in dowel openings 12 formed in the bottom mould plate 3 to pilot the top mould plate in proper oriented position for closing the mould plates to form a complete and closed mould.

Referring to Figures 16 and 18, the bottom cavity half 5 in the bottom mould plate 3 is provided with projections 13 in the tread-forming portions 14 of the cavity Sin order to form recesses in the moulded tyre. The cavity tread potion 14 terminates downwardly inwardly in a conical annular recess surface 15 terminating in a flat annular ringlike surface 16, which surrounds an upstanding central cylindrical pad 17 in which a central axial cylindrical knockout opening 18 is formed.

Other components of the bottom mould plate 3 include a base knockout plate 19, an annular bottom bite ring 20, and a knockout pin 21, which form an assembly by bolting the bite ring 20 with bolts 22 to the knockout plate 19, and by bolting the knockout pin 21 to the knockout plate 19 by bolts 23 (Figure 18).

The annular bottom bite ring 20 provides important functions and is formed of hardened steel. It has a tapered annular conical wedge surface 24 forming its outer periphery extending upwardly outwardly from bottom surface, and terminating in a flat annular horizontal shoulder surface 25. A sharp annular projection 26, V-shaped in cross section, projects upwardly from the annular shoulder surface 25 spaced radially outward from the central annular pilot head 27 of the bite ring 20. The pilot head 27 of the bite ring 20 has an upper outer cylindrical wall portion 28, connected by a conical, outwardly downwardly flared or tapered pilot wall portion 29, with an enlarged cylindrical lower wall portion 30.

The cylindrical wall 30 extends upward from the shoulder surface 25 (Figure 24) spaced radially inward of the sharp annular projection 26.

The outer peripheral edge 31 of the knockout plate 19 has a conically downward inward tapered wedge surface 32 which, when the bite ring 20 is assembled, as shown in Figure 18, with the knockout plate 19, forms a continuation of the conical wedge surface 24 of the bite ring 20. As well shown in Figure 18 to 22, the bite ring 20 is assembled with and fixed to the base knockout plate 19 by bolts 22 in an annular shouldered recess at the top annular cornerofthe knockout plate 19.

The bottom surface of the knockout plate 19 is formed with an annular recess 33 and a further annular subrecess 34. The annular recess 33 is complementary to and fits over the annular shoulder 17 in bottom mould plate 3, while the upper end of the knockout pin 21 is received in the subrecess 34 when the pin 21 is assembled by bolts 23 with the knockout plate.

When the base knockout plate-bite ring-knockout pin assembly 19,20,21 in turn is assembled with the bottom mould plate 3, the tapered wedge surfaces 24-32 mate in a complementary manner in the conical recess 15 formed in the bottom mould plate 3. During such assembly, the knockout pin 21 is telescoped into the central knockout opening 18 formed in the bottom mould plate 3. Relative movement between the knockout pin 21 and opening 18 may be guided and controlled by four guide pins 35 bolted by bolts 36 to the knockout plate 19 and projecting downward therefrom, spaced from and parallel with the knockout pin 21. These guide pins 35 are telescopically received in guide openings 37 formed in the bottom mould plate 3 (Figures 10, 16,18and27).

The knockout pin 21 preferably is formed with a T-slot 38 in its lower end (Figures 8, 10, 14, 18 and 22). The T-slot 38 is aligned longitudinally with the centre line of slot 9 in the bottom face 7a of the bottom mould plate 3 (Figures 8 and 10).

Referring to Figures 10 and 18, a pair of stop fingers 39 projecting laterally at right angles to the centre line of the T-slot 38 preferably are mounted on the lower end of the knockout pin 21. These fingers are received in vertical guide slots 40 formed in the central opening 18 in the bottom mould plate 3 so as to engage stop shoulders 41 at the upper ends of the guide slots 40 to limit upward movement of the knockout pin 21 in central knockout opening 18.

Referring to Figures 15 and 18, the top cavity half 4 in the top mould plate 2 is provided with projections 42 in the tread-forming portion 43 of the cavity 4, in order to form recesses in the moulded tyre similar to those formed by the projections 13 in the bottom mould plate 3. The cavity tread portion 43 terminates upwardly inwardly in a conical annular recess surface 44 terminating in a cylindrical surface 45 extending from a flat horizontal surface 46 having an upwardly recessed socket 47 therein.

A wedge member 48 has its cylindrical shank 49 seated in the recessed socket 47 and bolted by bolts 50 to the top mould plate 2. The wedge member 48 has an enlarged wedge head 51 extending downward from the shank 49. Wedge head 51 is formed with an annular conical downwardly and inwardly extending wedge surface 52. A plate 53 is bolted at 54 to the lower end of the wedge head 51 having its out peripheral edge projected radially outward of the lower end of conical surface 52 to form a shoulder 55 at the lower end of the wedge head.

The wedge head 51 is surrounded by a tapered split ring 56 having an inner conical surface 57 complementary to the conical surface 52 of the wedge head. Normally, the split wedge ring 56 has a slight clearance between its conical surface 57 and the conical surface 52 of the wedge head 51, as indicated at 58 in Figure 18. The split ring 56 is supported on the wedge member 48 by engagement of its shoulder 59 with the shoulder 55 formed by the plate 53.

Other components of the top mould plate 2 include a top knockout ring 60 having a top bite ring 61 assembled thereto by bolts 62 (Figures 9 and 29).

The top knockout ring 60 is supported by bolts 63 on the top mould plate 2 and is slidably, axially mounted on the cylindrical shank 49 of the wedge member 48. The top plate 60-bite ring 61 assembly is spring pressed downward, viewed in Figure 18, by spring 64.

The top bite ring 61, like the bottom bite ring 20, provides important functions and also is formed of hardened steel. It has a tapered annular conical outer wedge surface 65 forming its outer periphery, extending downwardly outwardly to its bottom surface where it terminates in a flat annular horizontal should surface 66. A sharp annular projection 67, V-shaped in cross section, projects downwardly from the annular shoulder surface 66 (Figure 23). An annular projecting pilot portion 68 projects downwardly from the shoulder surface 66 of the top bite ring 61 spaced radially inwardly from the sharp annular projection 67 on the bite ring.

As shown in Figure 18, the springs 64 normally press the top knockout ring 60 downward. Thus, the bite ring 61 is pressed downwardly and engages the top annular edge of split ring member 56, forcing the ring 56 downward so that its shoulder 59 engages and is supported by the shoulder 55 formed by bottom plate 53 on wedge member 48, thereby establishing the clearance 58 described above between split ring 56 and wedge head 51.

In this state, the top knockout ring 60 has been moved downward along and with respect to the cylindrical shank 49 of wedge member 48. There also thus is provided a clearance space, as shown in Figure 18, between the complementary conical wedge surface 44 formed in the top mould cavity and the conical wedge surface 65 on the top bite ring 61. This clearance is illustrated at 69 in Figure 18.

During this spring biased movement of the bite ring 61 its pilot portion 68 must clear the upper corner of the wedge head 51 formed by its conical surface 52.

The top and bottom mould plates 2 and 3 each are provided with sprue, runner and gate formations which when the top and bottom mould plates 2 and 3 are closed, as in Figures 7 to 10 and 22, form the sprue, runners and gate through which rubber compound is injected into the mould cavity 4-5.

These formations are best shown in Figures 15 and 16. The sprue formation in the top mould plate 2 is indicated generally at 70 and extends from the front end 71 of the top mould plate 2 toward the top cavity half 4 where it branches into runner formations 72 and 73 which extend in each direction a desired distance such as up to approximately 90 circumferentially around the open end of the tread portion 43 of the top cavity 4. A gate forming portion 74, described further below, communicates between the runners 72 and 73 and the top cavity half 4.

Passages 75 are formed in the back portion of the top mould plate 2 for connection with a source of vacuum, and the passages 75 each communicates with one of a pair of branch passages 76 which extend from the inner ends of passages 75 to the parting face 77 of the top mould plate 2. A substantially semi-circular vacuum runner and overflow formation 78 also is formed in the parting face 77 of the top mould plate 2 having gate communication with the top cavity half 4 of the top mould plate 2, described further below (Figure 15). If for some reason the mould when injected is overfilled with rubber compound the formation 78 acts as an overflow receptacle.

Similarly, the bottom mould plate 3 has a sprue formation 79 formed in the parting face 80 extending from the front end 10 of the bottom mould plate 3 toward the bottom cavity half 5 of bottom mould plate 3 where it branches into runner formations 82 and 83 extending circumferentially a desired distance in each direction from the sprue formation 79.

These runner formations 82 and 83 also communicate at the open end of bottom mould cavity half 5 by gate forming portions 84 (Figure 16).

When the top and bottom mould plates 2 and 3 are in closed position as shown in Figures 7 to 10, the opposed sprue, runner and gate formations in each, which are complementary, complete the formation of a sprue and runners and a gate for the mould cavity 4-5. The completed sprue connection is best indicated generally in Figure 8 at 85.

An elongated vacuum chamber formation 86 is formed in the parting face 80 of bottom mould plate 3 adjacent the rear of the bottom cavity half 5 (Figure 16) which communicates at each end with the branch vacuum passages 76 in the top mould plate 2 when the mould plates are in closed position with their parting faces 77 and 80 in contact locked under pressure. Runner formations 87 extend from each end of the vacuum chamber 86 to the semi-circular vacuum and overflow runner portion 88 formed in the parting face 80 of the bottom mould plate 3.

Thus, when the top and bottom mould plates 2 and 3 are in locked, closed position, vacuum can be imposed by connections with a vacuum source of vacuum passages 75 to draw gases through the vacuum passages 75 and 76, the vacuum chamber 86 and the vacuum runners 78, 87 and 88 from the closed mould cavity to enable complete filling of the mould cavity with rubber compound injected into the mould.

The complete operation of injection moulding solid steel-banded press-on industrial rubber tyres described below, using multi-station rubber injection moulding equipment having eight stations, accommodates eight separate closed moulds 2-3, one located at each of the eight stations, as illustrated in Figure 6. The first or injection station and the eighth or demoulding station are indicated generally at 89 and 90, respectively, in Figures 1 to 6.

A different tyre size may be made in each of the eight moulds; or if production of one tyre size should exceed other sizes, two of the moulds may be the same. In each case the cycle of operation passes any one mould from the injection station 89 to the demoulding station 90.

The use of any mould 2-3 does not require operation of an 8-station, multi-station injection installation since injection moulding can be carried out with the improved mould construction in a 2-station, multi-station injection moulding installation where the mould moves from an initial injection station to a final demoulding station using the same moulding time cycle that would be used when moulding is carried out on an 8-station installation where the time cycle is related to the time of movement from the injection station to the demoulding station.

A particular injected mould 2-3 upon arrival at the demoulding station 90, is opened. Then the bottom mould plate 3 with'a moulded tyre therein is removed from the mould carrier and is transferred to a mould knockout table where the tyre is removed.

Some of these operations and mechanisms used are illustrated somewhat diagrammatically in Figures 11, 12 and 13 as well as in Figures 4 and 6.

For convenience in description, the bottom mould plate 3 in Figure 11 is illustrated at the demoulding station 90, with the tyre removed and the mould plate 3 positioned on a transfer guideway 91 which is mounted on the revolving mould carrier table 92 of the multi-station injection moulding equipment.

Such bottom mould plate 3 location on revolving table 92 also is illustrated in Figure 17.

The mould carrier transfer guideway 91 at this stage in the moulding cycle is aligned with the transfer guideway 93 mounted on the top plate 94 of the mould knockout or service table 95. Meanwhile a transfer rod or drawbar 96 extending from a hydraulic cyclinder 97 located at the demoulding station (Figure 6) 90 has been positioned as shown in Figure 11 with its T-slot 98 adjacent the revolving table 92 oriented to receive the T-head 8 of mould plate 3 when said mould plate 3 on the table 92 is moved to and arrives at the demoulding station 90. In this manner the transfer drawbar 96 is coupled with the bottom mould plate 3 at the demoulding station.

Transferguideway members 91 and 93 have respective laterally spaced channel-shaped guide means 91a and 93a (Figures 14 and 17) which engage guide slots 6 in laterally spaced sides 6a (Figure 8) of mould plate 3 during transfer.

The transfer drawbar 96 then is moved by cylinder 97 in the direction of the arrow 99 (Figure 12) to transfer the bottom mould plate 3 from revolving table guideway 91 to knockout table guideway 93.

The bottom mould plate 3, during such movement, rolls on the rollers 7 shown in Figures 7 and 8. A moulded tyre 100 is illustrated in the bottom mould plate 3 in Figure 12 as the mould plate 3 is being transferred to the knockout table 95.

Referring to Figures 10, 13,14,22,27 and 28, the central slot 9 in the bottom face of bottom mould plate 3 has an important function. The lower end of knockout pin 21 extends into the slot 9 as shown in Figures 14, 18 and 27. The T-slot 38 in the lower end of knockout pin 21, as previously indicated, is aligned longitudinally with the centre line of bottom plate slot 9 so that as the bottom mould plate 3 is moved from the position of Figure 11 to the position of Figure 13 a T-head 101 at the top of knockout ram 102, on arrival of the bottom mould plate 3 at a predetermined position on the knockout table 95, engages said knockout pin T-slot 38 as shown in Figure 14, which illustrates the bottom mould plate 3 upon arrival at said predetermined location on knockout table 95.

The bottom mould plate 3 when at said predetermined position has the axis of the knockout pin 21 aligned with an opening 81 in the top plate 94 of knockout table 95 (Figure 11). The opening 81 provides a passage through which the knockout ram may extend to locate its T-head 101 in position to be coupled with the T-slot 38 at the lower end of knockout pin 21, when the bottom mould plate 3 is moved onto the knockout table 95.

The knockout ram 102 is actuated by a hydraulic cylinder 103 (Figure 28) to move the knockout pin 21 upward in the direction of the arrow 104. The knockout pin 21, as previously described, is mounted on the base knockout plate 19 and during upward movement of the knockout ram 102 and knockout pin 21 the bottom mould knockout plate 19 is dislodged from its position in the bottom cavity half 5 of the bottom mould plate 3 carrying the moulded tyre 100 with it to the knocked out position as illustrated in Figure 13. At this location the moulded tyre may be removed by handling equipment (not shown) to a trimming and inspection station.

Referring to Figures 9, 15, 16,22,30 and 31, the views in Figures 9, 15, 16 and 22 are on too small scales to show the nature and character of gates formed between the injection runner formations and the mould cavity and between the vacuum runner formations and the mould cavity. These gates, however, are shown somewhat diagrammatically by larger scale fragmentary views of Figures 30 and 31.

In Figure 30, the top and bottom mould plates 2 and 3 are shown closed with locked contact between their respective parting faces 77 and 80. Also shown is the registry between a top plate runner 72 and a bottom plate runner 83. The closed or complete runner 72-73, as shown, is spaced a slight distsance from the top and bottom cavity halves 4 and 5 respectively. This space is defined by the mould cavity forming wall portions 74 and 84 which define the injection gate between the injection runners and the mould cavity.

This injection gate is indicated generally at 107, and in Figure 30 the parting line between the top and bottom mould plates 2 and 3 is omitted for clarity where it runs through the injection gate 107. The clearance between wall portions 74 and 84, defining the injection gate 107, is very slight, being of the order of thousandths of an inch.

The injection gate spacing between wall portions 74 and 84, which may be said to be the gate thickness or clearance, may be varied, along with the length of the gate wall portions 74 and 84 between the runner and die cavity to ensure sufficient final heating of the rubber compound by friction developed during injection through the gate so that the temperature of the rubber in the mould cavity as filled is at the required curing temperature for the particular rubber compound involved. Thus, the injection velocity, and the width and length of the gate 107 determine the amount of shear heating of the injected uncured rubber compound which takes place, as well as the compound composition. For these reasons, in the injection moulding of different tyres, the gate clearance may be in the range of 0.020 inches to 0.060 inches thick.

Referring to Figure 31,the top and bottom mould plates 2 and 3 are shown closed with locked contact between their respective parting faces 77 and 80.

Also shown is the registry between the top plate vacuum runner 88. The closed vacuum runner 78-88, as shown, is spaced a slight distance from the top and bottom cavity halves 4 and 5 respectively. This space is defined by the mould cavity forming wall portions 108 and 109 which form the vacuum gate 110 between the vacuum runner and the mould cavity. The vacuum gate is formed by even less clearance than the clearance which forms the injection gate 107. In Figure 31, the parting line between the top and bottom mould plates 2 and 3 is omitted for clarity where it runs through the vacuum gate 110.

One of the critical concepts of the invention involves the co-ordination and inter-relation between and the particular constructions of the top and bottom mould plates 2 and 3 as well as of components assembled and functioning as a part of the two mould plates. These features are described below, referring to Figures 18,19,20,21, 23 and 24, first in connection with closing the mould plates 2 and 3 to form a closed mould ready to be injected with rubber compound. The co-ordination and inter-relation between the components then are described, referring to Figures 22, 23, 24, 25 and 26, in connection with injection of the mould, moulding and opening the mould after a solid steel-banded industrial rubber tyre has been cured therein.

A solid steel band or rim to which the solid rubber tread is bonded during moulding and curing is indicated at 111. The steel in this band is softer than the hardened steel from which the respective top and bottom bite rings 61 and 20 are formed. A steel band 111, when the mould is completely open, is inserted into bottom cavity half 5 of bottom mould plate 3 (Figure 18). At this time the mould plates 2 and 3 are separated vertically a much greater distance than shown in Figure 18. During placement of the band 111 in the bottom mould cavity, the conically flared portion 29 (Figure 24) of bottom bite ring 20 pilots the band 111 to axially align it with the vertical centre line of the bottom cavity half of bottom mould plate 3. Flared portion 29 directs the band 111 to a position surrounding the cylindrical wall portion 30 of the bite ring 20.

The top mould plate 2 then is moved downward in the closing direction of movement indicated by the arrow 112 in Figure 18 so that the dowels 11 enter the dowel openings 12 of the bottom mould plate 3 as shown in Figure 18 to assure proper registry or mating of the mould plates 2 and 3. At this stage of mould closing movement, the wedge member 48 and related components of the top mould plate 2 assembled to the latter have the relative positions and relationship shown in Figure 18, and wedge head 51 and split wedge ring 56 have just started to enter the interior of the steel band 111.

During continued downward closing movement of the top mould plate 2 toward the bottom mould plate 3, the parts reach the position shown in Figure 19. At this time, the annular pilot portion 68 (Figure 23) enters the upper open end of the steel band 111 to establish and maintain relative concentricity between the top and bottom mould plates, the mould cavities therein, and the steel band 111. The closing pressure imparted to the top mould plate 2 causes the sharp annular V-shaped projection 67 on the top bite ring 61 to engage the upper annular edge of the steel band 111. Meanwhile the sharp annular Vshaped projection 26 of the bottom bite ring 20 engages the lower annular edge of the steel band 111 as shown in Figure 19.

At this time, there is a space such as indicated at 113 in Figure 19 between the top and bottom mould plates 2 and 3. Also there is clearance indicated at 114 between the top surface of base knockout plate 19 and the bottom edge of split wedge ring 56. There is also clearance at this time between the top knockout ring 60 and the flat wall 46 of the cylindrical recess 45 in the top mould plate 2. Clearance also is present between the top bite ring 61 and the conical mould surface 44, as shown in Figure 19.

As the top mould plate 2 is closed further toward the bottom mould plate 3 as shown in Figure 20, the wedge head 51 of wedge member 48 expands the split wedge ring 56 so that the outer surface 138 engages the interior cylindrical surface 139 of the steel band 111. Meanwhile the springs 64 are compressed permitting cavity portions of the top mould plate 2 to approach portions of the top knockout ring 60 and related components as shown in Figure 20. At this stage in die plate closing, there is still a closing space 115 between the parting faces 77 and 80 of top and bottom mould plates 2 and 3; Complete closing of the top and bottom mould plates 2 and 3 is shown in Figure 21, with the respective parting faces of the plates in pressure contact and registry of mould cavity formations, etc., established.During this final closing movement from the position of the parts shown in Figure 20 to that of Figure 21, the V-shaped sharp annular projections or ribs 67 and 26 are forced into and wedge seated in the softer metal of the top and bottom annular edges of the steel band 111 as shown in Figure 21. The forced entry of the hardened steel V-shaped ribs into the metal of the top and bottom steel band edges displaces and deforms the band metal and seats the top and bottom annular edges of the steel band against the shoulder surface 66 of top bite ring 61 and against the shoulder surface 25 of the bottom bite ring 20 to provide seals between the top and bottom edges of the steel band 111 and the respective bite rings 61 and 20.

Meanwhile, the wedge head 51 continues its expanding pressure against the split ring 56 to rigidly support the cylindrical steel band 111 against distortion particularly inward distortion during later injection of the mould cavity with rubber compound.

As shown in Figure 21, the lower edge of split wedge ring 56 is pressed downward by the expanding force of wedge member 48, into pressure contact with the annular cylindrical wall portion 28 of bottom bite ring 20. Furthermore, the conical wedge surface 24 of bottom bite ring 20 is seated under pressure in wedge sealing contact with the conical recess 15 of the bottom mould plate 3, while the conical wedge surface 65 of top bite ring 61 is wedge seated in sealing contact under pressure against the conical recess 44 of top mould plate 2.

The completely closed and sealed mould, as just described, is locked in the closed position shown in Figures 21 and 22 and moulding pressure applied to the closed and locked mould plates 2 and 3 during operation of multi-stage moulding equipment described more in detail below.

Figure 22 generally illustrates the closed mould, after injection of rubber compound into the mould cavity and after the tyre has been cured therein, and when the mould is ready to be opened at a demoulding station 90. In this state, the top and bottom mould plates 2 and 3 and their components have the same relative relationship as is shown in Figure 21 prior to rubber compound injection.

Initial separation of the top and bottom mould plates 2 and 3 is indicated in Figure 25 by the small separating space 116 illustrated between the mould plates. This separation and related movement of components occur when the mould is opened during demoulding. The moulded tyre 100 remains in the bottom cavity half 5 as the top mould plate 2 is raised a short distance, in the direction of the arrow 117, from the bottom mould plate 3.

During this opening movement of the top mould plate 2, springs 64 force the top knockout plate 60 downward, releasing it from wedge seating in the top plate conical recess 44. At the same time the upper half of the moulded and cured tyre tread portion 118 is released from the top cavity of the top mould plate 2 (Figure 25).

As the top mould plate 2 continues its opening movement in the direction of the arrow 117 (Figure 26) to increase the mould plate separation as indicated at 119, the wedge head 51 of the wedge member 48 moves up relative to the split wedge ring 56 releasing its wedge pressure against the split ring 56. This relative movement occurs because the pilot portion 68 of the top bite ring 61 engages and holds the split ring 56 against movement due to the downward pressure of springs 64. Thus the split ring 56 is dislodged from wedge engagement between its conical surface 57 and the conical surface 52 of the wedge head 51, thereby re-establishing the clearance 58 therebetween. At this time, the split wedge ring 56 drops and is supported on the shoulder 55 of plate 53 on the wedge member 48.

In Figures 18, 19 and 26, a clearance space 58 is shown between the tapered wedge head surface 52 and the tapered split ring surface 57. Also, a clearance space 137 is indicated between the outer cylindrical surface 138 of split ring 56 and the inner cylindrical surface 139 of the band 111. These clearances 58 and 137 are very slight and the clearance 137 may be somewhat greater in dimension than the clearance 58. However, for the purpose of illustration and description, the clearance spaces 58 and 137 are shown exaggerated on a larger scale than they actually are, for clarity of illustration.

Also, it is important to note at this time that the radial thickness of the annular pilot portion 68 bite ring 61 must always be less than the radial spacing between the upper end of wedge head 51 and the internal cylindrical surface 139 of steel band 111 so that the pilot portion 68 can enter between the wedge head 51 and the steel band 111 during opening of the mould as in Figure 26, or during closing of the mould as in Figures 19 and 20.

The moulded tyre 100 with its solid rubber tread portion 118 bonded to the steel band 111 remains in the cavity of the bottom mould plate 3 as shown, for example, in Figure 12, during continued upward movement of the top mould plate 2 and its assem bled components, to completely open position.

The new moulds for injection moulding of solid steel-banded press-on industrial rubber tyres, hav ing the construction, components, and the described inter-related and interacting relationships, compris ing the top and bottom mould plate assemblies which function during mould closing, tyre moulding and curing, and mould opening, as described, may be used with multistage injection moulding equip ment and obtain numerous advantages described below.

The operation of an eight-station unit shown diagrammatically in Figures 1 to 6 may use any number of moulds for different sized tyres up to eight different moulds as previously indicated. One of the new moulds is mounted at each of the eight stations on a mould carrier indicated generally at 120 carried by the revolving table 92.

At each station, the bottom mould plate 3 assembly is mounted in a transfer guideway 91. The top mould plate 2 assembly is mounted at the lower end of a plunger 121 extending downward from a fast acting hydraulic cylinder 122 mounted on a bolster 123 at the top of each mould carrier 120. The bolster 123 with its arms 125 is mounted on the three main columns 126 of the mould carrier 120.

The mould at the injection station 89 is closed (Figure 2) by actuation of the fast acting hydraulic cylinder 122 and when closed locking bolts 124, three in number, carried by the plunger 121 are rotated to engage under the three arms 125 of the bolster 123 to lock the top and bottom mould plates 2 and 3 closed. The main high tonnage hydraulic pressure means exerting force upward below the bottom mould plate 3, carried by the revolving table at the bottom of each mould carrier 120 holds the moulds closed under high tonnage pressure. This pressure may be of the order of 500 metric tons pressure reacting against the locking bolts 124 and bolster 123 which hold the mould closed.

The lower end of the plunger 121 on which the top mould plate 2 is mounted may have electric heating elements preferably with thermostatic controls to maintain a predetermined curing temperature in the range of about 300 F to 330 F for the particular rubber compound injected into the mould.

Atypical multi-station injection moulding installation may include an injection unit generally indicated at 127. Uncured rubber compound stock in any desired form, usually strip form is fed through feed opening 128 to a supply compartment for a screw plasticizer rotating in a barrel to plasticize and beat the compound and inject the same when the injection head 129 is moved to injection position coupled with a mould as illustrated in Figures 3 and 6. At this time the injection nozzle 130 is seated in the sprue opening 85 of the closed mould (Figure 8).

During plasticizing in the barrel and injection head 129, the rubber compound becomes heated from developed friction. If necessary, the plasticizing heating of the compound may be augmented, controlled or cooled to provide plasticized rubber compound, as injected, having a temperature approaching the curing temperature of the particular compound injected.

Injection of the rubber compound into the mould cavity proceeds through sprue 85 formed by sprue formations 70 and 79 (Figures 8 and 22) and runners formed by runner formations 72, 73,82 and 83 (Figures 15 and 16) and through the injection gate 107 formed by gate portions 74 and 84 (Figure 30) into the mould cavity until the mould cavity is filled.

During such injection, gases in the runners and mould cavity are removed to enable complete mould fill with rubber compound, by the vacuum maintained in the vacuum chamber 86. Normallythe amount of rubber compound injected into the mould cavity is controlled by the injection unit 127 so that the mould is completely filled without overfill.

However, in order to assure complete filling, any overfill of rubber compound is extruded through the vacuum gate 110 into the vacuum and overflow runner 78-88.

During injection, due to friction developed as the injected rubber compound moves through the sprue, runners and slight clearance injection gate 107 further heats the compound to the cure temperature of the particular rubber compound. This is one of the known benefits of injection moulding which is advantageous in injection moulding solid industrial rubbertyres. Thus, during operation of multi-station moulding equipment the compound, as a result of injection, has an internal temperature, when the mould cavity has been injected completely, at the desired curing temperature and it is only necessary to supply heat during curing in a sufficient amount to maintain such desired curing temperature.

Solid steel-banded industrial rubbertyres of the general type illustrated have various steel band diameters and widths and various rubber tread dimensions. The moulds for the normal range of tyre sizes may require from say 15 to 35 pounds of rubber compound to fill the mould cavities around the steel band. Further, because of the tremendous required pressures existing during injection and curing, the rubber compound has a tendency to try to leak or escape between mating surfaces of mould plates and their assembled components. Further, these pressures also tend to bulge the steel tyre bands away from the cavity into which the rubber compound is injected.

Such rubber leakage or the formation of what is commonly called "flash" must be prevented. Otherwise expensive and time-consuming cleaning operations to clean the mould cavity and mould plates and components must be carried out to remove flash after each product has been moulded.

In accordance with the invention, leakage of rubber compound during injection and curing, and the consequent formation of flash, is prevented by the interaction between other components and the top and bottom bite rings 61 and 20, since the bite rings seal against the ends of the steel band and seat and seal against the conical recesses 44 and 15 of the top and bottom mould plates 2 and 3 when the mould plates are closed, locked and held under the high tonnage moulding pressure indicated.

Referring to Figure 21, since all mating surfaces in the regions at the ends of the steel band 111 are sealed, there is no flash formed at and around the mould components at these locations. The only other locations where flash and excess rubber can collect, which must be removed from the cured tyre, is along the injection and vacuum gates 107 and 110.

This flash is readily trimmed and separated from the mould plates when the mould is opened and can readily be removed from the cured tyre.

Afurther characterizing feature of the new mould construction and the interaction of the bite rings 61 and 20 with other components, involves the split ring wedge ring 56, the wedge member 48, and the spring controlled movable mounting of the top knockout ring 60 on the wedge member 48. This interaction functions to prevent distortion of the steel band 111 during injection and curing, and also functions to knock the moulded tyre out of the top mould plate when opening the mould as well as to dislodge the split ring wedge ring from pressure contact within the steel band.

After a mould injection step has been completed at injection station 89, the injection head 129 is withdrawn to the position shown in Figure 2, and upon indexed rotation of the revolving table 92 each mould carried by each of the remaining seven mould carriers 120 is successively injected, one at a time, at the injection station 89.

Meanwhile, when one of the moulds on a mould carrier arrives at the demoulding station 90, the locking bolts 124 are rotated to unlocked position and the plunger 121 is raised to open the mould in the manner described. During the time interval or cycle for an injected mould to be moved Qrom the injection station 89 to the demoulding station 90, the curing temperature of the compound in the mould is maintained as descrbed.

When the open mould arrives at the demoulding station 90 (Figures 4,6 and 11) the transport drawbar has engaged the T-head 8 on the bottom mould plate 3 as shown in Figure 11. The drawbar 96 then is moved in the direction of the arrow 99 (Figure 12) to the proper location on the knockout tale 95 where actuation of the knockout ram 102 knocks the cured tyre 100 out of the bottom mould plate 3 as shown in Figure 13.

The tyre 100 may be removed by handling equipment from the base knockout plate 19. The knockout pin 21 then is lowered and the bottom mould plate 3 is returned by the transport drawbar 96 to its transport guideway 91 on the mould carrier. When so returned, the open mould components at the demoulding station 90 are ready to be moved on the revolving table 92 to the injection station 89 for another cycle of operation.

A usual curing time, depending upon the tyre size, for steel-banded solid industrial rubbertyres produced by injection moulding as described may be from ten to fourteen minutes in contrast with the two to three-hour time cycle or curing time for the compression moulding of similar solid industrial rubber tyres.

Further, and equally important, are the improved characteristics of injection moulded solid industrial rubber tyres. Fatigue or destruction tests have been performed on injection moulded tyres which show a better tyre life than compression moulded tyres.

A modified form of construction of the bottom mould plate member is shown in Figure 32. The bottom mould plate member generally indicated at 131 omits a base knockout plate and the bottom bite ring 132 is received in the bottom recess 133 of the bottom mould plate 131 to which it is bolted at 134.

In mounting the bottom bite ring 132 in the bottom mould plate 131 complementary annular conical surfaces 135 and 136 formed, respectively, on the bite ring and in the mould plate recess are seated as described in connection with the bottom mould plate 3; and are sealed against injected rubber leakage by the high pressure maintained when the mould is closed and the mould plate members are locked together under pressure. Complementary conical surfaces 135 and 136, however, are not necessary on the bottom bite ring 132, because there is no place for rubber to leak to between the bite ring and the mould cavity recess in which the bite ring is seated, in the bottom mould plate 131.

Otherwise, the construction of and relationship of the modified bottom mould plate 131 to other components of the mould formed with a top mould plate 2 are the same as described in relation to the construction and operation of the mould illustrated, for example, in Figure 22.

Another modified form of construction of the bottom mould plate member is shown in Figure 33.

The bottom mould plate member generally indicated at 140 is somewhat similar to the bottom mould plate member 131 of Figure 32 but also omits a bottom bite ring and its annular V-shaped projection.

The bottom mould plate member 140 has a simple construction with a tread-forming cavity portion 141 formed therein similar to the tread-forming portion 13 in Figure 22. However, there is no recess in the bottom plate member 140 similar to the recess 133 in Figure 32.

The inner portion of the mount cavity of bottom mould plate member 140 is formed with a raised annular pilot portion 142 extending axially of the mould cavity formed with a cylindrical surface 143 which functions like the cylindrical wall 30 of the bottom bite ring 20 in Figure 22. The cylindrical surface 143 is connected by a conical pilot wall 143a with a smaller diameter cylindrical head surface 143b.

Thus, when a steel band 144 is inserted into the cavity of the bottom mould plate member 140, the pilot portion 143 locates the steel band 144 concen tricallywithin the mould cavity with its lower end 145 seated on the horizontal annular surface 146 which connects the tread-forming cavity portion 141 with the annular pilot portion 143 of the bottom mould plate member 140.

Otherwise the construction and relationship of the modified bottom mould plate member 140 to other components of the mould formed with a top mould plate member 2 are the same as described in relation to the construction and operation of the mould illustrated, for example, in Figure 22.

Thus, when the mould is closed and the top mould plate member 2 is mated with the bottom mould plate member 140, the top bite ring 61 is seated in its conical recess seat 65 in the top mould plate 2 against the biasing by springs 64, and the V-shaped annular projection 67 on the bite ring 61 is wedge seated, by band metal deformatfon in the upper end edge of the steel band 144 by the high pressure maintained when the mould is closed and the mould plate members are locked together under pressure.

During such mould closing movement, the lower end 145 of the steel band 144 is pressed in tight sealing engagement against the horizontal annular surface 146.

In this manner the tread-forming cavity portions of the top and bottom mould plate members are sealed against leakage of injected rubber past the ends of the steel band 144 into other portions and against other components of the mould.

Accordingly, the new mould construction and moulding procedure for injection moulding steel banded solid industrial rubbertyres avoid the diffi culties and disadvantages of prior compression moulding of such tyres, provide procedures and equipment which enable the first known production of injection moulded steel-banded industrial rubber tyres, provide an injection moulded tyre product having high quality characteristics, eliminate the long curing time heretofore required for compression moulding such steel-banded solid industrial rubber tyres, provide equipment and procedures satisfying the objectives stated, eliminate difficulties heretofore encountered in the art, and solve problems and satisfy needs that have existed in the art.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the new equipment and procedures of the invention are by way of example and the scope of the invention is not limited to the exact details shown or described, since solid steel-banded industrial rubber tyres of many sizes may be manufactured in accordance with the inventions.

Having now described the features and principles of the invention, the manner in which the new steel-banded solid tyre injection moulds are constructed and used, the functioning of components thereof, and the advantageous, new and useful results obtained; the new and useful structures, devices, components, elements, combinations, arrangements, uses, relationships and procedures are set forth in the appended claims.

Claims

1. Apparatus for injection moulding and curing rubber compound with a steel band inserted in a cavity formed in the mould to bond rubber injected into the cavity to the band during curing thereby forming a solid steel-banded industrial rubbertyre, including mating first and second mould plate members defining with a steel band inserted between the plate members a rubber tread-forming cavity surrounding the band when the plate members are mated under pressure; a hardened steel bite ring located within a recess formed in the first mould plate member adjacent the tread-forming cavity portion therein; the bite ring being movable in its recess and having a conical circumferential surface seated under sealing pressure in a complementary conical portion of the first mould plate member recess when the mould plate members are mated; the bite ring having a V-shaped annular projection wedge seated, by band metal deformation when the plate members are pressure mated, in one end of the steel band insert which defines a portion of said cavity; said bite ring being mounted on a first knockout member movably mounted on the first mould plate; said first knockout member being biassed toward the second mould plate member when the mould is closed; the moulded steelbanded tyre being knocked out by the biassed first knockout member from the first plate member cavity portion upon opening the mould; means for inject ing rubber compound into and for extracting gases from said cavity; and radially expansible means operative on closing the mould to internally engage a steel band insert and hold it against distortion from high injection pressure during rubber injection and during curing of injected rubber in said cavity.

2. Apparatus as claimed in claim 1 in which the tread-forming cavity portion of the second mould plate member has an annular pilot portion extending axially within said tread-forming mould cavity portion; in which said pilot portion has a cylindrical surface extending from a horizontal annular surface which connects said tread-forming cavity portion with said pilot portion; and in which a second end of said steel band insert is adapted to telescope over said cylindrical pilot portion surface when inserted into the second mould plate member to center the band in the tread-forming cavity portion of said second mould plate member.

3. Apparatus as claimed in claim 2 in which said pilot portion has a pilot head provided with an outer cylindrical surface of smaller diameter than its cylindrical surface which engages a steel band end portion; and in which said pilot head cylindrical surface is connected with the steel-band-engaging cylindrical surface by a conical outwardly down wardlyflared pilot wall.

4. Apparatus as claimed in claim 1 in which said radially expansible means includes, a wedge member having a shank connected to a recess portion of said first mould plate member extending axially of the plate member tread-forming cavity and terminating in an enlarged wedge head, a downwardly inwardly extending circumferential conical surface formed on said wedge head, a split ring surrounding said wedge head, and means supporting said split ring on said wedge head; in which the first mould plate member has a parting face surrounding the open end of its tread-forming cavity; in which the conical wedge head surface projects beyond the parting face of said first mould plate member; and in which said split ring has an inner conical surface complementary to said wedge head conical surface, and an outer cylindrical surface adapted in closing the mould to be telescoped within and to internally engage a steel band insert in said second mould plate member tread-forming cavity.

5. Apparatus as claimed in claim 4 in which on closing the mould and telescoping the wedge head and split ring supporting thereon within a steel band insert in said second mould plate member cavity, the split ring engages said pilot portion, and in which during final closing movement of said first mould plate member to mate with said second mould plate member said wedge head moves axially relative to the split ring engaged with said pilot portion and expands said split ring into distortion resisting pressure engagement with the inner surface of said steel band insert.

6. Apparatus as claimed in claim 4 in which the smaller diameter end portion of said wedge head is provided with annular shoulder means; and in which said split ring normally is supported on said shoulder means when said first and second mould plate members are axially separated in open position.

7. Apparatus as claimed in claim 6 in which the wedge head shoulder means comprises a plate mounted on the outer end of the wedge head having an annular edge shoulder portion projecting radially outwardly of the conical wedge head surface; and in which said split ring has an annular shoulder engageable with said plate shoulder portion.

8. Apparatus as claimed in claim 4 in which said first biassed knockout member and said bite ring mounted thereon are mounted on and aretnovable relative to said wedge member shank biased toward said wedge head; in which said first knockout member is ring-like and has a circumferential conical surface formed as an axial continuation of said bite ring conical surface in which said conical first knockout ring and bite ring surfaces seat under pressure sealing engagement in said complementary conical portion of said first mould plate member recess when said mould plate members are mated; and in which spring means are mounted on the first mould plate member to bias said first knockout ring member and said bite ring mounted thereon out of seated sealing engagement with said first mould plate member recess to thereby knock a moulded tyre out of the rubber tread-forming cavity portion of said first mould plate member when a tyre has been cured in the mould and the mated mould plate members are initially moved relatively to each other to separate the mould plate members.

9. Apparatus as claimed in claim 8 in which during continued relative separating movement of said mould plate members and the consequent continued spring biassed movement of said bite ring out of said seated sealing engagement with said first mould plate member recess, said bite ring pilot portion engages said split ring and moves said split ring relative to said wedge head to release split ring engagement with the steel band of the tyre cured in the mould, thereby permitting relative separation movement of said first and second mould plate members to continue for fully opening the mould.

10. Apparatus as claimed in claim 1 in which a knockout table is provided adjacent the location during a moulding and curing operation of said second mould plate member; and in which transfer means are provided to move said second mould plate member with a cured tyre retained in its mould cavity portion to said adjacent knockout table.

11. Apparatus as claimed in claim 10 in which said transfer means includes a first transfer guideway member on which said second mould plate member rests during a moulding and curing operation, a second transfer guideway member mounted on said knockout table, the second mould plate member having roller means on which it is supported on said first transfer guideway means during a moulding and curing operation, laterally spaced channel-shaped guide means located on each of said first and second transfer guideway members longitudinally aligned with each other, the second mould plate member having a front end and laterally spaced sides, transfer guide slots formed in said second mould plate member sides slidably engageable with said laterally spaced aligned first and second transfer guideway member channel-shaped guide means, and drawbar means engageable with said second mould plate member for moving said bottom mould plate member on said roller means to and fro between said first and second transfer guideway members.

12. Apparatus as claimed in claim 11 in which said drawbar means for moving said second mould plate member to and fro between said first and second transfer guideway members includes a power actuated reciprocable transfer drawbar, and Thead and T-slot coupling means respectively mounted on said second mould plate member and said drewbar releasably engageable for moving said second mould plate means when said drawbar is actuated.

13. Apparatus as claimed in claim 1 in which said first and second mould plate members have parting faces which contact each other when said plate members are mated underpressure to complete the formation of a mould cavity; in which said means for injecting rubber compound into said cavity includes as a part of said first and second mould plate members, mating sprue, runner and gate formations in the parting faces of said first and second mould plate members through which rubber compound is injected from an injection unit into said cavity; in which said runner formations extend along a circumferential portion of and communicate through said gate formations with the cavity halves of the first and second mould plate members; and in which said gate formations in the parting faces of said first and second mould plate members have a very slight injection gate clearance space therebetween so as to, by developed friction, heat to the curing temperature of the rubber compound injected, said rubber compound as it passes through said gate into said cavity.

14. Apparatus as claimed in claim 13 in which the injection gate clearance space dimension is of the order of 0.020 inches to 0.060 inches.

15. Apparatus as claimed in claim 1 in which said first and second mould plate members have parting faces which contact each other when said plate members are mated under pressure to complete the formation of a mold cavity; in which said means for injecting rubber compound into said cavity includes as a part of said first and second mould plate members, mating injection sprue, runner and gate formations in the parting faces oçf said first and second mould plate members through which rubber compound is injected from an injection unit into said cavity; in which mating vacuum runner and overflow and gate formations are formed in the parting faces of said first and second mould plate members through which gases are extracted from said cavity to permit complete fill of said cavity with injected rubber compound; in which said vacuum runner and overflow formations extend along a circumferential portion of and communicate through said vacuum gate formations with the cavity halves of the first and second mould plate members; in which a vacuum chamber is formed in the parting face of said second mould plate member communicating with said vacuum runner and overflowformations; and in which passages are formed in said first mould plate member adapted to be connected with a source of vacuum and communicating at the parting face of said first mould plate member with said vacuum chamber.

16. Apparatus as claimed in claim 15 in which the mating injection gate formations form an injection gate with a clearance space having a predetermined dimension; and in which said vacuum gate formations form a vacuum gate clearance space having a dimension less than said predetermined injection gate clearance space dimension.

17. Apparatus for injection moulding and curing rubber compound with a steel band inserted in a cavity formed in the mould to bond rubber injected into the cavity to the band during curing thereby forming a solid steel-banded industrial rubbertyre, including mating first and second mould plate members defining with a steel band inserted between the plate members a rubber tread-forming cavity surrounding the band when the plate members are mated under pressure; first and second hardened steel bite rings located within recesses formed in the respective mould plate members adjacent the tread-forming cavity portions therein; at least the first bite ring being movable in its respective recess and having a conical circumferential surface seated under sealing pressure in a complementary conical portion of the first mould plate member recess when the mould plate members are mated; each bite ring having a V-shaped annular projection wedge seated, by band metal deformation when the plate members are pressure mated, in opposite ends of the steel band insert which defines a portion of said cavity; said first bite ring being mounted on a first knockout member movably mounted on the first mould plate; said first knockout member being biassed toward the second mould plate member when the mould is closed; the moulded steel-banded tyre being knocked out by the biassed first knockout member from the first plate member cavity portion upon opening the mould; means for injecting rubber compound into and for extracting gases from said cavity; and radially expansible means operative on closing the mold to internally engage a steel band insert and hold it against distortion from high injection pressure during rubber injection and during curing of injected rubber in said cavity.

18. Apparatus as claimed in claim 17 in which said second bite ring also has a conical circumferential surface seated under sealing pressure in a complementary conical portion of the second mould plate member recess when the mould plate members are mated; in which enlarged ends of the bite ring conical surfaces terminate in flat annular horizontal shoulder surfaces having axially extending annular pilot portions spaced radially inward of said enlarged ends; in which said annular V-shaped projections are formed on said should surfaces in alignment intermediate respective pilot portions and enlarged ends; in which said pilot portions have outer axially aligned cylindrical surfaces adapted to telescope into and engage opposite end portions of the inner cylindrical surface of a steel band insert to center the band in the mould cavity as the V-shaped bite ring projections wedge seat by band metal deformation in opposite ends of the band insert when said mould plate members are pressure mated together.

19. Apparatus as claimed in claim 18 in which said second bite ring pilot portion has a pilot head provided with an outer cylindrical surface of smaller diameter than its cylindrical surface which engages a steel band end portion; and in which said pilot head cylindrical surface is connected with the steel band engaging cylinder surface by a conical outwardly downwardly flared pilot wall.

20. Apparatus as claimed in claim 17 in which said radially expansible means includes, a wedge member having a shank connected to a recess portion of said first mould plate member extending axially of the plate member tread-forming cavity and terminating in an enlarged wedge head, a downwardly inwardly extending circumferential conical surface formed on said wedge head, a split ring surrounding said wedge head, and means supporting said split ring on said wedge head; in which the first mould plate member has a parting face surrounding the open end of its tread-forming cavity; in which the conicial wedge head surface projects beyond the parting face of said first mould plate member; and in which said split ring has an inner conical surface complementary to said wedge head conical surface, and an outer cylindrical surface adapted on closing the mould to be telescoped within and to internally engage a steel band insert in said second mould membertread4orming cavity.

21. Apparatus as claimed in claim 20 in which on closing the mould and telescoping the wedge head and split ring supported thereon within a steel band insert in said second mould plate member cavity, the split ring engages said second bite ring, and in which during final closing movement of said first mould plate member to mate with said second mould plate member said wedge head moves axially relative to the split ring engaged with said second bite ring and expands said split ring into distortion resisting pressure engagement with the inner surface of said steel band insert.

22. Apparatus as claimed in claim 20 in which the smaller diameter end portion of said wedge head is provided with annular shoulder means; and in which said split ring normally is supported on said shoulder means when said first and second mould plate members are axially separated in open position.

23. Apparatus as claimed in claim 22 in which the wedge head shoulder means comprises a plate mounted on the outer end of the wedge head having an annular edge shoulder portion projecting radially outwardly of the conical wedge head surface; and in which said split ring has an annular shoulder engageable with said plate shoulder portion.

24. Apparatus as claimed in claim 20 in which said first biassed knockout member and said first bite ring mounted thereon are mounted on and are movable relative to said wedge member shank biassed toward said wedge head; in which said first knockout member is ring-like and has a circumferential conical surface formed as an axial continuation of said first bite ring conical surface; in which said conical first knockout ring and first bit ring surfaces seat under pressure sealing engagement in said complementary conical portion of said first mould plate member recess when said mould plate members are mated; and in which spring means are mounted on the first mould plate member to bias said first knockout ring member and said first bite ring mounted thereon out of seated sealing engagement with said first mould plate member recess to thereby knock a moulded tyre out of the rubber tread-forming cavity portion of said first mould plate member when a tyre has been cured in the mould and the mated mould plate members arezinitially moved relatively to each other to separate the mould plate members.

25. Apparatus as claimed in claim 24 in which during continued relative separating movement of said mould plate members and the consequent continued spring biassed movement of said first bite ring out of said seated sealing engagement with said first mould plate member recess, said first bite ring pilot portion engages said split ring and moves said split ring relative to said wedge head to release split ring engagement with the steel band of the tyre cured in the mould, thereby permitting relative separation movement of said first and second mould plate members to continue for fully opening the mould.

26. Apparatus as claimed in claim 17 in which said second bite ring is mounted on a second knockout member; in which said second knockout member is axially movably mounted in said second mould plate member recess; in which said second mould plate has a parting face, and a bottom face; in which an axial opening extends in the second mould plate member from the second mould plate member recess to said bottom face; in which a knockout pin is mounted on said second knockout member extending axially toward said bottom face in said knockout opening; and in which there are means releasably engageable with said knockout pin for moving the knockout pin in said knockout opening toward said parting face to knock the second knockout member and the second bite ring mounted thereon and a steel banded tyre cured in the mould cavity whose band is engaged with the second bite ring out of the mould cavity portion in said second mould plate member.

27. Apparatus as claimed in claim 26 in which a knockout table is provided adjacent the location during a moulding and curing operation of said second mould plate member; and in which transfer means are provided to move said second mould plate member with a cured tyre retained in its mould cavity portion to said adjacent knockout table.

28. Apparatus as claimed in claim 27 in which said transfer means includes a first transfer guideway member on which said second mould plate member rests during a moulding and curing operation, a second transfer guideway member mounted on said knockout table, the second mould plate member having roller means on which it is supported on said first transfer guideway means during a moulding and curing operation, laterally spaced channel shaped guide means located on each of said first and second transfer guideway members iongitudinally aligned with each other, the second mould plate member having a front end and laterally spaced sides, transfer guide slots formed in said second mould plate member sides slidably engageable with said laterally spaced aligned first and second transfer guideway member channel shaped guide means, and drawbar means engageable with said second mould plate member for moving said bottorh mould plate member on said roller means to and fro between said first and second transfer guideway members.

29. Apparatus as claimed in claim 28 in which said drawbar means for moving said second mould plate member to and fro between said first and second transfer guideway members includes a power actuated reciprocable transfer drawbar, and Thead and T-slot coupling means respectively mounted on said second mould plate member and said drawbar releasably engageable for moving said second mould plate means when said drawbar is actuated.

30. Apparatus as claimed in claim 29 in which said knockout table and said second transfer guideway member are provided with knockout passage opening means aligned with the axial opening in said second mould plate member when the latter is located on said knockout table; in which power actuated reciprocable knockout ram means are mounted on said knockout table below said second transfer guideway member extending through said knockout passage opening means for moving said knockout pin axially toward the second mould plate member parting face to knock said knockout plate with a cured tyre thereon out of the second mould plate member cavity portion; and releasable coupling means inter-engageable between said knockout ram means and said knockout pin.

31. Apparatus as claimed in claim 30 in which said releasable coupling means between said knockout ram means and said knockout pin includes, a central slot formed in the bottom face of the second mould plate member communicating with the lower end of said knockout pin and extending to the front end of the second mould plate member, a T-slot formed in the lower end of said knockout pin accessible to said central slot, and a T-head formed on said knockout ram means, whereby as the second mould plate member is transferred to the knockout table said central slot passes along said ram means T-head which projects into said slot and said T-head engages the knockout pin T-slot when the second mould plate member arrives at a position on the knockout table with the knockout pin axially aligned with said knockout ram means.

32. Apparatus as claimed in claim 17 in which said first and second mould plate members have parting faces which contact each other when said plate members are mated under pressure to com plete the formation of a mould cavity; in which said means for injecting rubber compound into said cavity includes as a part of said first and second mould plate members, mating sprue, runner and gate formations in the parting faces of said first and second mould plate members through which rubber compound is injected from an injection unit into said cavity; in which said runner formations extend along a circumferential portion of and communicate through said gate formations with the cavity halves of the first and second mould plate members; and in which said gate formations in the parting faces of said first and secmond mould plate members have a very slight injection gate clearance space therebetween so as to, by developed friction, heat to the curing temperature of the rubber compound injected, said rubber compound as it passes through said gate into said cavity.

33. Apparatus as claimed in claim 32 in which the injection gate clearance space dimension is of the order of 0.020 inches to 0.060 inches.

34. Apparatus as claimed in claim 17 in which said first and second mould plate members have parting faces which contact each other when said plate members are mated under pressure to complete the formation of a mould cavity; in which said means for injecting rubber compound into said cavity includes as a part of said first and second mould plate members, mating injection sprue, runner and gate formations in the parting faces of said first and second mould plate members through which rubber compound is injected from an injection unit into said cavity; in which mating vacuum runner and overflow and gate formations are formed in the parting faces of said first and second mould plate members through which gases are extracted from said cavity to permit complete fill of said cavity with injected rubber compound; in which said vacuum runner and overflow formations extend along a circumferential portion of and communicate through said vacuum gate formations with the cavity halves of the first and second mould plate members; in which a vacuum chamber is formed in the parting face of said second mould plate member communicating with said vacuum runner and overflow formations; and in which passages are formed in said first mould plate member adapted to be connected with a source of vacuum and communicating at the parting face of said first mould plate member with said vacuum chamber.

35. Apparatus as claimed in claim 34 in which the mating injection gate formations form an injection gate with a clearance spaced having a predetermined dimension; and in which said vacuum gate formations form a vacuum gate clearance space having a dimension less than said predetermined injection gate clearance space.

36. A method of injection moulding and curing rubber compound with a steel band in a cavity formed in a mould to bond rubber injected into the cavity to the band during curing to form a solid steel-banded industrial rubbertyre; comprising providing separated top and bottom mould plate members having cavity portions therein; locating in recesses formed in respective plate members top and bottom hardened steel bite rings having conical circumferential surfaces which are complementary to conical surfaces formed in said recesses; providing annular V-shaped projections on said bite rings; biassing said top bite ring away from said top plate member conical recess portion; inserting a steel band in the bottom mould plate member cavity portion; piloting said steel band on the bottom bite ring during insertion to a position concentric with the bottom mould plate cavity portion; relatively moving said top and bottom mould plate members toward each other to mate said plate members and form a closed mould cavity; during said relative movement piloting said biassed top bite ring into concentric engagement with the upper end of said steel band; meanwhile engaging said top and bottom bite ring annular V-formations with the ends of said steel band and wedge seating by band metal deformation said V-shaped formations into the metal band ends to seal the bite rings against the band ends; meanwhile seal-pressure-seating said conical bite ring surfaces in said plate member conical recess portions, and also pressure-mating parting faces of said top and bottom mould plates; holding the steel band under pressure against interior distortion; pressure injecting rubber compound at compound curing temperature into the cavity formed by the plate member cavity portions and the steel band; curing the injected rubber and maintaining moulding pressure on the mated mould plate members and the seated and sealed bite rings and steel band during curing; maintaining the temperature of the injected rubber compound at its curing temperature during curing; then after curing, separating the mould plate members, and during initial separation knocking the cured steel-banded tyre out of the top mould plate member cavity; then releasing distortion preventing pressure from the steel band; and then removing said tyre from the bottom mould plate member cavity.

37. Apparatus for injection moulding and curing rubber compound with a steel band inserted in a cavity formed in the mould to bond rubber injected into the cavity to the band during curing thereby forming a solid steel-banded industrial rubbertyre, including mating first and second mould plate members defining with a steel band inserted between the plate members a rubbertread4orming cavity surrounding the band when the plate members are mated under pressure; first and second hardened steel bit rings movably contained within recesses formed in respective mould plate members adjacent the tread-forming cavity portions therein; the bite rings each having conical circumferential surfaces seated under sealing pressure in complementary conical portions of the recesses in respective mould plate members, and having Vshaped annular projections wedge seated, by band metal deformation when the plate members are pressure mated, in opposite ends of a steel band insert which defines a portion, of said cavity; said bite rings being mounted on respective first and second knockout members movably mounted on their respective mould plate members; said first knockout member being biassed toward the second knockout member when the mould is closed, the moulded steel-banded tyre being knocked out by the biassed first knockout member from the first plate member cavity portion upon opening the mould; the second knockout member being movable to knock the moulded tyre out of the second plate member cavity portion after opening the mould; means for injecting rubber compound into and for extracting gases from said cavity; and radially expansible means operative on closing the mould to internally engage the steel band insert and hold it against distortion from high injection pressure during rubber injection and during curing of injected rubber in said cavity.

38. Apparatus for injecting moulded solid steelbanded industrial rubber tyres, incmluding mating top and bottom mould plate means each including a plate having a parting face, an axially extending annular recess, and an annular tyre tread-forming cavity portion extending from said face to said recess, each recess having an axially extending conical wedge surface; a top knockout member located in the top recess; an axially extending wedge member having a shank mounted in the top plate recess and an enlarged wedge head having a conical surface; the wedge head being radially spaced internally from said cavity and extending axially from the shank out of said cavity beyond the top plate parting face; the top knockout member being axially movably mounted on said shank biassed toward the wedge head; a split ring support on said wedge head having an outer cylindrical steel-tyreband-engageable surface and an inner conical surface surrounding and complementary to the wedge head conical surface; a first hardened steel bite ring mounted on the top knockout member; a second hardened steel bite ring mounted in said bottom plate recess; each bite ring having a shoulder and a pilot portion extending toward the other bite ring from such shoulder; each shoulder having an annularV-shaped projection extending from such shoulder toward the V-shaped projection formed on the other bite ring in circumferential alignment therewith; each shoulder terminating in a conical annular wedge surface complementary to and adapted to be seated within and in sealing relation with the respective plate conical recess surface; mating rubber compound injection sprue, runner and gate formations in the parting faces of said top and bottom plates communicating with a circumferential portion of the cavity formed by said top and bottom mould plate means tyre tread-forming cavity portions when said mould plate means and their parting faces are mated and held under pressure; and vacuum means for extracting gases from said formed cavity during rubber compound injection.

39. Apparatus for injection moulding solid steelbanded industrial rubbertyres, including mating top and bottom mould plate means each including a plate having a parting face, an axially extending annular recess, and an annular tyre tread-forming cavity portion extending from said face to said recess, each recess having an axially extending conical wedge surface; top and bottom knockout members located in the respective top and bottom recesses; an axially extending wedge member having a shank mounted in the top plate recess and an enlarged wedge head having a conical surface, the wedge head being radially spaced interiorly from said cavity and extending axially from the shank out of said cavity beyond the top plate parting face; the top knockout member being axially movably mounted on said shank biassed toward the wedge head; a split ring supported on said wedge head having an outer cylindrical steel-tyre-bandengageable surface an an inner conical surface surrounding and complementary to the wedge head conical surface; the bottom plate having a lower face spaced from its parting face and being formed with a knockout opening extending axially from said bottom plate recess to said lower face; the bottom knockout member having a knockout pin mounted thereon telescoped into and movable in said knockout opening; the top and bottom knockout members each having a hardened steel bite ring mounted thereon, each bit ring having a shoulder and a pilot portion extending toward the other bite ring from such shoulder, each shoulder having an annular V-shaped projection extending from such shoulder toward the V-shaped projection formed on the other bite ring in circumferential alignment therewith; each shoulder terminating in a conical annular wedge surface complementary to and adapted to be seated within and in sealing relation with the respective plate conical recess surface; mating rubber compound injection sprue, runner and gate formations in the parting faces of said top and bottom plates communicating with a circumferential portion of the cavity formed by said top and bottom mould plate means tread-forming cavity portions when said mould plate means have their parting faces mated and held under pressure; and vacuum means for extracting gases from said formed cavity during rubber compound injection.

40. A method of injection moulding and curingrubber compound with a steel band in a cavity formed in a mould to bond rubber injected into the cavity to the band during curing to form a solid steel-banded industrial rubbertyre; comprising providing separated top and bottom mould plate members having cavity portions therein; locating in recesses formed in respective plate members top and bottom hardened steel bite rings at least the top bite ring of which bite rings has a conical circumferential surface which is complementary to a conical surface formed in said top plate member recess; providing annular V-shaped p'rojections on said bite rings; biassing said top bite ring away from said top plate member conical recess portion; inserting a steel band in the bottom mould'plate member cavity portion; piloting said steel band on the bottom bite ring during insertion to a position concentric with the bottom mould plate cavity portion; relatively moving said top and bottom mould plate members toward each other to mate said plate members and form a closed mould cavity; during said relative movement piloting said biassed top bite ring into concentric engagement with the upper end of said steel band; meanwhile engaging said top and bottom bite ring annular V-formations with the ends of said steel band and wedge seating by band metal deformation said V-shaped formations into the met al band ends to seal the bite rings against the band ends; meanwhile seal-pressure-seating said top con ical bite ring surface in said top plate member conical recess portion, and also pressure-mating parting faces of said top and bottom mould plates; holding the steel band under pressure against interior distortion; pressure injecting rubber compound at compound curing temperature into the cavity formed by the plate member cavity portions and the steel band; curing the injected rubber and maintaining moulding pressure on the mated mould plate members and the seated and sealed bite rings and steel band during curing; maintaining the temperature of the injected rubber compound at its curing temperature during curing; then after curing, separating the mould plate members, and during initial separation knocking the cured steel-banded tyre out of the top mould plate member cavity; then releasing distortion preventing pressure from the steel band; and then removing said tyre from the bottom mould plate member cavity.

41. A method of injection moulding and curing rubber compound with a steel band in a cavity formed in a mould to bond rubber injected into the cavity to the band during curing to form a solid steel-banded industrial rubbertyre; comprising providing separated top and bottom mould plate members having cavity portions therein; locating in a recess formed in said top plate member a hardened steel bite ring having a conical circumferential surface which is complementary to a conical surface formed in said top plate member recess; providing an annular V-shaped projection on said bite ring; biassing said bite ring away from said top plate member conical recess portion; inserting a steel band in the bottom mould plate member cavity portion; piloting said steel band during insertion to a position concentric with the bottom mould plate cavity portion; relatively moving said top and bottom mould plate members toward each otherto mate said plate members and form a closed mold cavity; during said relative movement piloting said biassed bite ring into concentric engagement with the upper end of said steel band; meanwhile engaging said bite ring annular V-formation with the top end of said steel band and wedge-seating by band metal deformation said V-shaped formation into the metal baind top end to seal the bite ring against the band top end while at the same time the metal band bottom end is pressed in tight sealing against a horizontal annular surface in the bottom mould plate member; meanwhile seal-pressure-seating said conical bite ring surface in said top plate member conical recess portion, and also pressure-mating parting faces of said top and bottom mould plates; holding the steel band under pressure against interior distortion; pressure injecting rubber compound at compound curing temperature into the cavity formed by the plate member cavity portions and the steel band; curing the injected rubber and maintaining moulding pressure on the mated mould plate members and the seated and sealed bite ring and steel band during curing; maintaining the temperature of the injected rubber compound at its curing temperature during curing; then after curing, separating the mould plate members, and during initial separation knocking the cured steel-banded tyre out of the top mould plate member cavity; then releasing distortion preventing preventing pressure from the steel band; and then removing said tyre from the bottom mould plate member cavity.

42. Apparatus for forming a solid steel-banded industrial rubber tyre substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

43. A method of forming a solid steel-banded industrial rubber tyre substantially as hereinbefore described with reference to the accompanying drawings.