FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Mold Clamping Mechanism For A Tire Curing Press"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Mold Clamping Mechanism For A Tire Curing Press
Field of the invention
The present invention relates to a tire curing press, and more particularly, the present invention relates toa mold clamping mechanism for a tire curing press.
Background of the invention
Tire curing press is used for shaping and curing pneumatic tires. During operation, there are chances that upper and lower sections/cavities of a mold may get separated due to the application of curing force. Thus, it is very essential to lock the upper mold and the lower mold cavities.
There are various mechanisms available for clamping and locking the mold cavities. For example, US Patent No. 4,647,273 discloses use of tie rods in presses. The tie rods are fixed to the moving cavity and locked to the fixed cavity of the mold. The disadvantage of this technology is that, for locking each tie rod to the fixed cavity, individual locking mechanism is required which is complicated and bulky.
Another US Patent No.4,332,536 discloses use of hydraulic cylinders mounted to the structures. The disadvantage of this type mechanism is that, the force flow during curing is completed through the whole structure, which results in a heavy and bulky support structure.
Another way of achieving the requirement is by using a lock ring between the upper mold and the lower mold cavities as disclosed in the US Patent No's 4,332,536

and4.390,334. The disadvantage of thislocking mechanism is that it is outside the cavity and thus decides the compactness and foot print of the whole press.
Accordingly,. there is a need for a tire curing press having a mold clamping mechanism that overcomes the problems in the prior art.
Objects of the present invention
An object of the present invention is to provide a compact tire curing press.
Another object of the present invention is to lock the upper and lower mold cavities during curing and achieve the locking inside the cavity thereby achieving a compact footprint.
Yet another object of the present invention is to lock the mold cavities and at the same time isolate the curing force from the support structures of the tire curing
press,
Still another object of the present invention is to facilitate height adjustment of the flexible mold of the tire curing press.
Summary of the invention
Accordingly, the present invention provides a tire curing press having a mold clamping mechanism. The tire curing press comprises a base, an upper housing secured to the base, a guide column assembly, a loader-unloader assembly, a lock ring and a segment mold operator capable of rotating the lock ring.

The base has a hydraulic actuator and a support plate configured with a plurality of first tooth members. The upper housing includes a mold having an upper mold cavity and a lower mold cavity.The guide column assembly includes a plurality of guide columns and at least one cam follower rail. The guide columns are vertically mounted on the upper mold cavity and the lower mold cavity. The cam follower rail guides movement of the upper housing.The loader-unloader assembly is mounted on the guide column assembly.The lock ring is supported on the support plate for locking the upper mold cavity to the lower mold cavity. The lock ring includes an inner surface and an outer surface. The inner surface has a plurality of second tooth members that are locked into the gaps between the plurality of first tooth members of the support plate. The outer surface has a plurality of upper flanges and a plurality of lower flanges. The upper and lower flanges are adapted to select the mold height range to be accommodated in the tire curing press.
Typically, wherein the height of the lower flange is lower than the height of the upper flange to accommodate a plurality of flanges of the upper mold cavity of the upper housing.
Typically, wherein the lock ring is free to rotate and move from the upper mold cavity of the upper housing to the lower mold cavity due to a slot and pin sliding mechanism employed by the segment mold operator and the hydraulic actuator, respectively.
Brief description of the invention
The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein.

Figure 1 shows a cross sectional view of a tire curing press having a mold clamping mechanism, in accordance with the present invention;
Figure 2 shows a top view of the tire curing press offigure 1;
Figure 3shows a top view of a support plate of figure 1;
Figure 4shows a perspective view of a section of an upper mold cavity of figure 1;
Figure 5shows a cross sectional view of the mold clamping mechanismin accordance with the present invention;and
Figure 6shows a top view of the mold clamping mechanismin accordance with the present invention.
Detailed description of the invention
The foregoing objects of the present invention are accompiished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
The present invention provides a mold clamping mechanism for a tire curing press. The mechanism is in the form of a lock ring that is used in tire curing presses for clamping the upper and the lower mold cavities during the shaping and curing of pneumatic tireS- The mechanism stays within the mold cavity at the same time isolates the curing force from the support structures.The mechanism is also useful for height adjustment of the flexible mold.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.
Referring now to figures 1 and 2. there is shown a cross sectional and a top view of a tire curing press (1000) having a mold clamping mechanism (hereinafter "the press (1000)"). The press (1000) comprises a base (100), an upper housing (200), a guide column assembly (300), a loader-unloader assembly (400). alock ring (500) and a segment mold operator (600).
The base (100) has at least one open end. In an embodiment,the base (100) is open from afront end to ensure easy serviceability, accessibility and maintenance of the components of the press (1000). The base (100) is secured and leveled to the floor using a plurality of securing and leveling means. In an embodiment, the securing and leveling means are foundation bolts and jack screws respectively. The base (100) includes a squeeze cylinder (110), a support plate (120) and a hydraulic actuator (130). The hydraulic actuator (130) and the support plate (120) are alternatively called as a hydraulic lift cylinder and a mounting plate, respectively. The support plate (120) has a plurality of first tooth member (120a)that are spaced apart by a fixed distance as shown in figure 3. The base (100) includes theupper housing (200) secured thereto.
The upper housing (200)is used for accommodating molds of different heights. The mold has an upper mold cavity (210) and a lower mold cavity (212). The upper mold cavity (210) is provided with a plurality of flanges (210a) as shown in figure 4. The upper housing (200) further includes a top steam platen (220), a bottom

steam platen (230), a bottom platen support (240), and at least one hydraulic cylinder (250) as shown in figure 1.
The upper mold cavity (210) is secured to the upper housing (200) through thetop steam platen (220). The lower mold cavity (232) is fixedly mounted on thebottom platen support (240) through the bottom steam platen (230) securing with the base (10). The bottom platen support (240) is rigidly connected with thesqueeze cylinder (110) through thesupport plate (120). The squeeze cylinder (110) is given appropriate stroke based on the mold height to be accommodated in the press (1000). Depending on the stroke applied to the squeeze cylinder (110). there is a change in the position of the lower mold cavity (212) on the bottom platen support (240). The upper mold and the lower mold cavities (210, 212) includes the guide column assembly (300) mounted thereon.
The guide column assembly (300) has at least four guide columns (310) as shown in figure 2, and at least one cam follower rail (320) as shown in figure 5. The guide columns (310) are vertically mounted on the either sides of the upper mold and the lower mold cavities (210, 212) forming a V pattern. The V orientation reduces the foot print space of the press (1000). The cam follower rails (320) are present on the sides of the guide column assembly (300). The support plate (120) is fixed with the cam follower rails (320). The cam follower rails (320) are meant for guiding the hydraulic actuator (130) for the upward and downward movements of the upper housing (200). The guide column assembly includes the loader-unloader assembly (400) mounted thereon.
The loader-unloader assembly (400) includes a loader (410) for loading green tires into a molding station (not shown) of the press (1000) from a green tire holder and an unloader (420) for unloading the cured tires out of the molding station of the

press (1000) to a surge conveyor (not shown) at a rear of the press (1000). The loader (410) and unloader (420) include a mechanical chuck (not shown) that uses a slider linkage mechanism for moving a group of interconnected paddles (not shown) in a circular path while keeping the paddles concentric with the chuck center.The cam follower rails (320) also guide the up-down movement of the loader-unloader assembly (400) by using linear motion guide ways on the front face and also by means of the hydraulic cylinder (250).
Further, the upper housing (200) is held in the lock ring (500) as shown in figure 1. The lock ring (500) is alternatively called as a bayonet ring. The flanges (210a) of the upper mold cavity (210) are locked with the lock ring (500).In an embodiment. the lock ring (500) has an "E" cross section. It is, understood, however, that the lock ring can have any shape of cross section in alternative embodiments of the tire curing press (1000). The lock ring (500) has an inner and an outer surface as shown in figure 6. The inner surface of the lock ring (500)comprises a plurality of second tooth member(310). During the curing operation, the plurality of second tooth members (310)passesthrough the gaps in between the plurality of first tooth members (120a) of the support plate (120) and gets locked upon being turned.
The outer surface of the lock ring (500) comprises a plurality ofupper flanges(520) anda plurality oflower flanges (522). The upper and lower flanges (520, 522) are used for selecting the mold height range to be accommodated in the press (1000). The flanges (520,522) of the lock ring (500)are used to lock to the flanges (210a) provided in the upper mold cavity (210). The flanges (210a)of the upper mold cavity (210)are locked with either of the flanges (520, 522) of the lock ring (500) depending upon the mold height range to be accommodated in the press (1000).

The lock ring (500) is fixedly attached to the support plate (120)to hold the lock ring (500)in a position during the curing process. The height of the lower flange (522) in the lock ring (500) is higher than the height of the upper flange (520) to accommodate the flange (120a) of the upper housing (200) and plurality of first tooth member (120a) of the support plate (120) for the smaller size mold.
Lock ring (500) is free for limited rotation on the support plate (120). The upper mold cavity (210) can move vertically and engage with upper or lower flanges (520 or 522) of the lock ring to achieve locking and different mold heights.
The lock ring (500) is rotated on the support plate (120) by a hydraulic actuator (not shown) fixed pivotally on the base (100) of the curing press.
The position of the squeeze cylinder (110) rod / the bottom platen support (240) is sensed using a plurality of sensing means (not shown) and the signal is communicated to a programmable logic controller (PLC)(not shown) to allow mold height adjustment through the PLC. Thus, the upper housing (200) is used for accommodating molds of different heights based on the lock ring (500) flanges (520, 522) that select the mold height range and the squeeze cylinder (110) for fine adjustments within the selected range.
Advantages of the present invention:
1. The lock ring (500) of the present invention results in compact mold cavity.
2. The lock ring (500)of the present invention reduces the footprint of the tire curing press (1000).
3. The lock ring (500)of the present invention reduces the weight of the tire curing press (1000).

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.

What is claimed is:
1. A tire curing press with a mold clamping mechanism, the tire curing
presscomprising:
a base having a hydraulic actuator and a support plate, the support plate configured with a plurality of first tooth members:
an upper housing secured to the base, the upper housing having a mold with an upper mold cavity and a lower mold cavity; a guide column assembly having.
at least four guide columns mounted on the upper mold cavity and the lower mold cavity, and
at least onecam follower rail guiding the movement of the upper housing;
a loader-unloader assembly mounted on the guide column assembly; a lock ring supported on the support plate, the lock ring capable of locking the upper mold cavity to the lower mold cavity, the lock ring having,
an inner surface having a plurality of second tooth members, the plurality of second tooth memberslocking into the gaps between the plurality of first tooth members of the support plate:
an outer surface having a plurality of upper flanges and a plurality of lower flanges, the upper flanges and the lower flanges are adapted to select the mold height range to be accommodated in the tire curing press; and
a segment mold operator capable of rotating the lock ring.
2. The tire curing press as claimed in claim 1. wherein the height of the
lower flange is higher than the height of the upper flange of the lock ring to
accommodate a plurality of flanges of the upper mold cavity.

3. The tire curing press as clamed in claim 1. where in lock ring is free for limited rotation on the support structure and upper mold cavity is free to move vertically and engage with the upper or lower flanges of the lock ring to achieve locking and different mold heights.
4. The tire curing press as claimed in claim 1, wherein the lock ring is rotated by a hydraulic actuator pivotally mounted to the base of the curing press.
5. The tire curing press as clamed in claim 1, wherein the lock ring rotates on a support structure by a hydraulic actuator and lock the upper and lower mold cavity from inside the cavity.