US3574893A

US3574893A - Tire-vulcanizing press

Info

Publication number: US3574893A
Application number: US825168A
Authority: US
Inventors: Walter Balle; Gunter Pommer
Original assignee: HERBERT MASCHF L
Current assignee: HERBERT MASCHF L; LEONHARD HERBERT MASCHINENFABRIK
Priority date: 1968-05-17
Filing date: 1969-05-16
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13
Also published as: FR2009909A1; ES367334A1; DE1778615A1; DE1778615B2; DK131978C; GB1203929A; DK131978B

Abstract

A tire-vulcanizing press which has particular application to tires of smaller size, e.g. those used for private cars including a heating bag arranged folded double between an inner and an outer cylinder on the lower part of a press, the inner cylinder acting as a bag-guiding cylinder and having means for positioning the cylinder at different levels and the outer cylinder acting to eject a tire from the lower half of a mould, and means on the closing of the press to adjust the height of the inner cylinder and thus the amount of the bag within a tire.

Description

United States lnventors Appl. No.

Filed Patented Assignee Priority aet Walter Balle Dornigheim;

Gunter Pommer, Frankfurt am Main, Germany May 16, 1969 Apr. 13, 1971 Leonhard Herbert Maschinenfabrik May 17, 1968 Germany TIRE-VULCANISING PRESS 5 Claims, 5 Drawing Figs.

US. Cl 18/17, 18/2 Int. Cl 82% 5/02 Field of Search 18/17 (K,

[56] References Cited UNITED STATES PATENTS 2,730,763 1/1956 Brundage 2,736,059 2/1956 Frank 2,858,566 11/1958 Brundage 8/ 1968 Balle et al.

Primary ExaminerJ. Howard F lint, J r. AttorneyWatson, Cole, Gn'ndle & Watson 18/17 18/17 18/17 l8/l7X ABSTRACT: A tire-vulcanizing press which has particular application to tires of smaller size, e.g. those used for private cars including a heating bag arranged folded double between an inner and an outer cylinder on the lower part of a press, the inner cylinder acting as a bag-guiding cylinder and having means for positioning the cylinder at different levels and the outer cylinder acting to eject a tire from the lower half of a mould, and means on the closing of the press to adjust the height of the inner cylinder and thus the amount of the bag within a tire.

Pmnied ml 13, 1971 I 3,574,893

.4 Shuts-Shut 1 Inventor; WFZZieP 'BzZQe Gunter PomeP 5y I 4 rue.

Patented A ril 13, 1911 i. 3,574,893

4 ShootB-Shfit s v Fig. L

' Inventor V1412 Z A BaZZe 6 712 6 P0 mm TlRE-VULCANISING PRESS BACKGROUND OF THE INVENTION The invention relates to a tire-vulcanizing press for the vulcanization of preformed tire carcases, which has particular, though not exclusive, application to tires of small sizes which are to be retreaded, e.g. tires for private cars, and which includes a heating bag which may be inserted whilst folded double into an annular space between two cylinders arranged one within the other and relatively movable axially, the outer of these two cylinders carrying an annular rim seat and the inner cylinder acting as a guide for the bag.

Tires of different dimensions can be vulcanized on a tirevulcanizing press of a given size, it being necessary to install the appropriate mould in the press for each tire size. In the case of large tires, as employed for commercial vehicles, a relatively small number of different sizes is in use, whereas a multiplicity of different sizes is'in use in the case of smaller tires, as used on private cars. For this reason, it may be acceptable to change the heating bag during conversion, which is rather infrequent, for another tire size, during production or retreading of large tires. It is preferable however to avoid the exchange of this heating bag in the case of the vulcanization of smaller tires, and in particular in the case of retreading them, different tire sizes occurring very frequently, because a relatively long working period would be lost by adapting the presses, and very many bags of different size would have to be stocked.

The expansibility of the heating bag easily renders it possible to vulcanize tires of different size with one and the same bag, if care is taken to ensure that only such part of the bag as corresponds approximately to the tire size, is inserted into the cavity of the tire.

Different devices are known to effect such an adjustment of the heating bag. In the case of presses possessing a driving mechanism for the insertion of the bag, it is thus known to fit exchangeable stops to the driving mechanism, which establish different vertical levels of rings clamping the bag. In the case of vulcanizing tires of larger cross section, into which a considerable part of the bag is inserted, the stops employed are shorter, whereas longer stops are employed in the case of vulcanizing tires of smaller cross section into which a smaller part of the bag is inserted. It is also known to employ and adjusting spindle instead of exchangeable stops. A scale must be incorporated in this case, which indicates the correlation between the position of the nut on the spindle and the tire size.

In the case of an electrically motorized driving device for the bag, it has already been suggested, moreover, that an electric motor supplying the driving power for the insertion of the bag, be switched off accordingly by means of a camoperated switch.

the present invention is based on the problem of devising a structurally uncomplicated heating bag setting device for a press of the kind initially referred to, which renders it possible to place the heating bag in the correct working position without employing setting scales or measuring operations, under exclusion of exchangeable parts.

SUMMARY According to the present invention, there is provided a tirevulcanising press for vulcanizing preformed tire carcasses, including an upper part and a lower part, a mould having an upper half on the upper part of the press'and a lower half on the lower part of the press, and an assembly on the lower part of the press having an outer cylinder, a seat ring for a tire rim on the outer cylinder, a driving system for the outer cylinder, the outer cylinder being movable axially bythe driving system to eject a tire from the lower half of the mould, an inner cylinder within the outer cylinder, a locking device for holding the inner cylinder at a predetermined level, a heating bag which may be arranged when folded double in the annular space between the inner and outer cylinders, clamping rings connected to the inner cylinder between which the edges of the bag may be clamped, and resilient means for urging the inner cylinder towards and against a part connected to the upper part of the press during the closing of the press.

The invention exploits the fact that the so-called aperture i.e. the gap between the rims of a tire, has an approximately constant relationship to its internal periphery measured in a radial sectioning plane. The axial rim gap thus provides an approximate measure for the internal periphery of the tire, so that the setting of the heating bag may be made a function of the rim gap. A setting corresponding to the rim gap is now available in a press according to the invention. The greater the rim gap, that is to say the greater the bag length to be inserted into the tire, the shorter the distance through which the bagguiding cylinder with the bag attached thereto is thrust back, since the upper half of the mould, a component of which makes a rearward displacement, does not come as close to the lower part of the press for a tire having a greater rim gap, as for a tire having a smaller rim gap. The upper half of the mould thus thrusts back the clamping points of the bag, i.e. its lower clamps, precisely as far as to ensure that only such part of the bag as is required for fully lining the tire cavity with the bag, still projects into the tire cavity. Ifthis position is reached during the first closing of the press, the corresponding position of the bag-guiding cylinder is maintained by the locking device and no longer changes during subsequent vulcanization of tiresof the same size. Devices according to the invention are structurally extremely simple and perfectly reliable, and operate in an almost wholly automatic manner. All that is needed is to lock the immobilizing device, which operation could easily be made automatic moreover.

In a preferred embodiment of the invention, the part of the upper half of the mould which thrusts the bag-guiding cylinder back into the correct working position, consists of an upper tire rim seat ring. To this end, the upper tire rim seat ring has formed on it a narrow inferior annular area which bears against a corresponding annular area of the bag-guiding cylinder in the closed position of the press. This annular area on the bag-guiding cylinder may be formed on the base of the bag-guiding cylinder. This base may simultaneously form an element of the bag-clamping system, namely the upper bagclamping ring. The application of the upper rim seat ring as the element exerting a retracting thrust is advantageous because the upper rim seat ring is the most widely projecting element which can easily be brought into contact with the bagguiding cylinder. In principle, it is possible however to employ a separate abutment for this purpose.

On the base of the bag-guiding cylinder there may be situated a central and downwardly extending rod which cooperates with an immobilizing or locking device firmly connected to the lower part of the press. This locking device may be a clamping sleeve enfianking the rod, which can be opened and released by means of one or more clamping screws accessible from the outside of the press. As shown by practical tests, a clamping system of this nature may easily be wrought so robustly that the bag-guiding cylinder is not forced back even when the full internal pressure of the heating bag acts on the press. The cooperation between a rod and a clamping sleeve also allows for infinitely variable adjustment of the vertical position of the bag-guiding cylinder.

Below its clamped area, the rod may be encircled by a coil compression spring, the lower extremity of which bears on the lower part of the press and the upper extremity of which bears on a shoulder formed on the rod, constantly exerting a force on the rod impelling the same upwards.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 shows a vertical radial section through a press in the state following the placing in position of a tire to be vulcanized for retreading purposes, the upper part of the press already having been lowered a little;

FIG. 2 shows a similar view to that of FIG. 1 with the press in a condition in which a pressurized fluid cylinder exerts a thrust on an ejector cylinder, and an initial inflation pressure has already been established in a heating bag;

FIG. 3 shows a view similar to that of FIG. 1 with the press closed completely and the heating bag under pressure;

FIG. 4 shows a radial section through the press in the area of the mould on an enlarged scale compared with that of the preceding FIGS.; and

FIG. 5 shows a section corresponding to that shown in FIG. 4, during the vulcanization of a tire of greater size.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings it may be seen from FIG. 1 that the press has a lower part 1 which carries a lower half 2 of a mould, and an upper part 3 displaceable relative to the lower part and on which there is the upper half 4 of the mould. The displacement of the upper part 3 of the press with respect to the stationary lower part 1 of the press is achieved by means of a powerful driving mechanism which is not illustrated and which is arranged to provide a substantial closing pressure.

The lower part 1 of the press includes a platform or table 5, a part 6 of the lower half 2 of the mould carried on a heating plate 7 and being arranged on this table with the interposition of an insulating plate 8. There is a wide opening 9 in the table, from which a projection 10 extends downwards. At its lower end the projection 10 carries a robust base 11.

The base 11 has secured to it a driving system provided by two pressure fluid cylinders 12 and 12b in which are slidable double-acting pistons, having piston rods 13a, 13b fastened to a base 14 of an ejector cylinder 15. On its upper edge, the ejector cylinder 15 carries a lower rim seat ring 16.

A bag-guiding cylinder 17 is coaxially arranged relative to the ejector cylinder 15. A heating bag 18 is clamped fast on the lower extremity of this bag-guiding cylinder. This heating bag is folded double about a folding point 19. The heating bag I has two edges having

respective beads

20 and 21 which are clamped fast onto the lower extremity of the bag-guiding cylinder 17. The upper bead" 20 is clamped between a lower edge 22 of the bag-guiding cylinder 17 and a spacing ring 23, and the lower bead is clamped between the spacing ring 23 and a lower clamping ring or plate 24. The lower edge 22, the spacing ring or plate 23 and the lower plate 24 together form an assembly which may be fastened on to a baseplate or lower clamping ring 25, in such a way that the parts of the assembly are pressed against each other tightly so that any ingress of fluid under pressure form the clamping points of the

beads

20, 21 is impossible. An intermediate space 26 for the reception of the bag 18 is situated between the ejector cylinder 15 and the bag-guiding cylinder 17. i

A central and downwardly projecting rod 27 of circular cross section is situated on the bag-guiding cylinder 17. This rod 27 passes through a clamping sleeve 28 which forms a locking device and which is firmly connected to the base 11 of the projection 10 from the press table 5. The clamping sleeve 28 has a cut in radial direction at one point, and a clamping screw 29 which extends at right angles to the cut or slit is provided by means of which the clamping sleeve can be compressed so as to clamp the rod 27 fast.

To the base 11 there is also secured a sleeve 30 having a base 31 and surrounding the rod 27. In an annular space between the sleeve 30 and the rod 27 there is situated a compression coil spring 32 which bears against the base 31 of the sleeve 30 at the bottom and against a shoulder 33 of the rod 27 at the top. The initial loading of the spring is such that it tends to press the rod 27 upwards at all times.

The rod has a central bore 34 forming a pressure fluid feed pipe and opening near the top into a radial bore 35 in the spacing plate 23. The radial bore leads into the cavity of the bag-18.

Another element on the lower part I of the press is a thrust rod 36 connected to the base 14 of the ejector cylinder 15,

and having an upper end face 37 which acts as a stop in manner yet to be described.

The upper part 3 of the press has a fastening plate 38, with an insulating plate 41 and a heating plate 40, on which there is secured a part 39 of the upper half 4 of the mould. On the plate 38 there is arranged an upwardly extending projection 42 which is closed off at its upper end by a plate 43. On the plate 43 there is arranged a pressure fluid cylinder 44 whose effective cross section is greater than the total effective cross section of the two lower

pressure fluid cylinders

12a and 12b. On the piston rod 45 of the piston sliding in the cylinder 44 there is fastened the base 46 of a cylinder 47 which carries an upper rim seat ring 48 on its lower extremity. This upper rim seat ring 48 has a narrow lower end face 49 as well as a conical surface 50. The function of these surfaces is yet to be described. A thrust or abutment rod 51 projects downwards from the cover 46 of the cylinder 47. This thrust rod is aligned with the lower thrust rod 36. Its lower end face 52 is an abutment surface and can cooperate with the abutment surface 37 of the lower rod 36.

The bag-guiding cylinder 17, with the bag fastened to it, and the associated parts, are shown in greater detail in FIGS. 4 and 5. It may be seen from FIG. 4 that the bag-guiding cylinder 17 extends downwardly and has a bag-clamping ring 53 which has a narrow annular surface 54. The ring 53 is screwed to the spacing ring 23 by means of studs 55 and nuts 56. Another screwed connection, not illustrated, is made between the lower clamping ring 25 and the spacing ring 23. In the ring 53 and the spacing ring 23 there are grooves which together form a cross section in which the upper bead 20 of the bag 18 is clamped fast. Grooves are also formed in the ring 25 and the spacing ring 23, together forming a cavity for clamping the lower bead 21 of the bag.

The rod 27 has a shoulder 58 on which the plate 25 rests. The plate 25 is welded to the rod. The diametrically neckeddown upper part of the rod 27 has a neck portion of reduced diameter which passes through the spacing ring 23. A nut 57 presses the assembly consisting of the upper ring 53, the spacing ring 23 and the lower ring 24 against the baseplate 25 through the spacing ring 23 and the ring 24.

The operation of the press will now be described.

It is assumed that a preceding vulcanizing cycle has been completed and that a vulcanized tire has already been stripped from the mould. In this case, the elements of the lower part of the press will be situated in the position shown in FIG. 1, in which the bag 18 has disappeared almost completely into the annular space 26 between the ejector cylinder 15 and the bagguiding cylinder 17. A tire 59 to be retreaded, which is already coated with crude rubber, has been placed on the lower rim seat ring 16. Furthermore in the arrangement shown in FIG. 1 the downward displacement of the upper part 3 of the press has already started. Together with the downward displacement of the upper part 3 of the press, the upper rim seat ring 48 is moved downwards, relative to the upper part 3 of the press, under the action of the pressure fluid cylinder 44. The ring 48 passes the bag-guiding cylinder and finally bears on the upper rim of the tire. The upper part 3 of the press now continues its downward movement (see FIG. 2) until the

rods

51 and 36 come into contact. The upper rod 51 thereupon causes the ejector cylinder to be pressed downwards. This is possible since the upper pressure fluid cylinder 44 develops a greater force than the two lower pressure fluid cylinders 12a and ll2b together. During this downward displacement of the ejector cylinder 15, the ejector cylinder 15 slides along the bag 18, and the bag is guided into the tire cavity by the conical surface 50 on the upper rim seat ring 48. When the heating bag 18 has been substantially inserted into the tire cavity, a little pressure (initial inflation pressure) is fed to the bag through the pressure fluid feed pipe 34, so that the bag is brought against the inner side of the tire. The heating bag is fully inserted into the tire when the upper half of the mould bears on the lower half of the mould.

At the end of the closing operation, the lower annular surface 49 of the upper rim annulus 48 is placed on the annular surface 54 on the ring 53 (see FIG. 4). At this time, the pressure fluid cylinders 12 and 12b are also actuated in such manner as to move the ejector cylinder 15 downwards until the lower rim seat ring 16 is brought into contact with the part 6 of the lower half of the mould. The

rods

51 and 36 are again drawn apart slightly during this action (see FIGS. 3 to 5).

Internal pressure is now built up in the heating bag and the vulcanization of the tire is begun. Upon opening the press after completion of the vulcanizing operation, the upper part 3 of the mould is raised first, thereby being removed from the upper side of the tire 59. The upper rim seat ring 48 may be controlled at the same time in such manner as to hold down the tire so that the tire cannot be entrained by the upper half of the mould. The ejector cylinder 15 is then raised and removes the vulcanized tire from the lower half 2 of the mould. The tire is then lifted off the lower rim seat ring 16 manually, and another tire to be vulcanized is placed on the ring 16. The clamping sleeve 28 and thus the position of the bag relative to the lower part of the press remain unchanged, for as long as the same tire size is to be processed. With a tire of a size which corresponds to that shown in FIG. 4 it is unnecessary as may be seen from FIGS. 3 and 4 for the entire heating bag to be inserted into the tire cavity. From FIG. 4 it may be seen that a surplus portion 60 of the bag remained in contact with the inner side of the lower rim seat ring 16, owing to the fact that the bag-guiding cylinder with its clamping device for the bag had been adjusted to the corresponding depth.

If however a tire of another size were to be handled necessitating the insertion of the entire bag into the tire cavity (see FIG. 5), the upper and lower rim seat rings as well as the two halves of the mould giving a height h, (FIG. 4), would be dismantled initially. A new mould (height h,, FIG. 5) and the corresponding rim seat rings, would then be inserted. The same rim seat rings as inthe previous case may be employed if the tire in question has the same diameter as that of the tire previously processed. After this assembly change the press is closed partially, and the locking device 28 on the rod 57 is released by loosening the screw 29. The spring 32 then thrusts the rod 27 and the clamping rings, upwards. The spring is so dimensioned that the clamping rings are thrust into a slightly higher position than is necessary for the widest tire that can still be processed in the press.

The press is then closed, the lower annular surface 49 of the upper rim seat ring 48 being placed on the annular surface 54 on the base ring 53 of the bag-guiding cylinder 17, and rearwardly displacing the bag-guiding cylinder together with the rod 27 against the force of the spring 32, the spring 32 being compressed thereby. When the press is'closed completely, the clamping rings are situated at precisely the height for clamping points of the bag to be correctly positioned with respect to the tire. This is attributable to the fast that the rim gap m (FIG. 5) of a tire has an approximately constant relationship with the cross-sectional periphery U of the tire. As may be seen by comparing FIGS. 4 and 5, the clamping points of the bag are now situated at a higher level relative to the tire than before, so that a greater part of the bag is inserted into the tire cavity, being almost the whole of the bag in the present case. After closing the press, the clamping sleeve 28 is clamped tight again, thereby locking the vertical level of the bag. Freeing then becomes necessary only for adaptation to another tire size.

It is apparent from FIG. 3 in particular, that the pressure fluid bore 35 opens into the bag at the lowest point. This has the advantage of satisfactory and speedy draining, since when the fluid used is water any steam formed during draining above the surface of the water exerts pressure on the surface of the water and forces the water out through the outflow bore.

l. A tire-vulcanlzlng press for vulcanizing preformed tire carcasses, including an upper part and a lower part, a mould having an upper half on the upper part of the press and a lower half on the lower part of the press, and an assembly on the lower part of the press having an outer cylinder, a seat ring for a tire rim on the outer cylinder, a driving system for the outer cylinder, the outer cylinder being movable axially by the driving system to eject a tire from the lower half of the mould, an inner cylinder within the outer cylinder, a locking device for holding the inner cylinder at a predetermined level, a heating bag which may be arranged when folded double in the annular space between the inner and outer cylinders, clamping rings connected to the inner cylinder between which the edges of the bag may be clamped, and resilient means for urging the inner cylinder towards and against a part connected to the upper part of the press during the closing of the press.

2. A tire-vulcanizing press as claimed in claim 1, including an upper seat ring for a tire rim forming a part of the upper part of the press and an annular surface on the inner cylinder, the arrangement being such that in the closed position of the press the upper seat ring is in contact with the annular surface on the inner cylinder.

3. A tire-vulcanizing press as claimed in claim 1, including a central and downwardly extending rod having the locking device for cooperation with the lower part of the press.

4. A tire-vulcanizing press as claimed in claim 3, in which the locking device is a clamping sleeve which can be opened and clamped by means of a clamping screw accessible from the outside of the press.

5. A tire-vulcanizing press as claimed in claim 3, including a compression coil spring providing the resilient means and having its lower end bearing against the lower part of the press and its upper end bearing against a shoulder on the rod.

Claims

1. A tire-vulcanizing press for vulcanizing preformed tire carcasses, including an upper part and a lower part, a mould having an upper half on the upper part of the press and a lower half on the lower part of the press, and an assembly on the lower part of the press having an outer cylinder, a seat ring for a tire rim on the outer cylinder, a driving system for the outer cylinder, the outer cylinder being movable axially by the driving system to eject a tire from the lower half of the mould, an inner cylinder within the outer cylinder, a locking device for holding the inner cylinder at a predetermined level, a heating bag which may be arranged when folded double in the annular space between the inner and outer cylinders, clamping rings connected to the inner cylinder between which the edges of the bag may be clamped, and resilient means for urging the inner cylinder towards and against a part connected to the upper part of the press during the closing of the press.