FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION [See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Rolling Shoe Chuck Assembly in Loader and Unloader of 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 & T0UBRO 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.

Rolling Shoe Chuck Assembly in Loader and Unloader of a Tire Curing
Press
Field of the invention
The present invention relates to a tire loader in a tire curing press, and more particularly, the present invention relates to a rolling shoe chuck assembly in loader and unloader of the tire curing press.
Background of the invention
The advent of automation in tire industry has resulted in various techniques to cut down many labor intensive operations involved in converting a raw rubber into a finished tire. Many attempts have been made over the years in a tire curing press to reduce cycle time in the manufacturing of the tire, thereby increasing the productivity. A tire loading and unloading device aids the automation in the tire curing process by automatically grabbing an uncured tire from a conveyor/tire holder and placing it on to a center mechanism of the tire curing press prior to the closing of the tire curing press and commencement of the curing cycle. Further, the tire loading and unloading device picks up the cured tire from the center mechanism after the press is being opened and completion of the curing cycle for placing the same on the conveyor belt.
Various the tire loading and unloading devices are in existence made according to a particular tire curing press for a particular tire configuration. However, these the tire loading and unloading devices are not focused on achieving precise positioning of tire on to the center mechanism as it's considered to be less important.

However, with the advent of a radial tire, it has become very much essential to locate the tire very accurately and precisely to the center of a mold cavity for obtaining best tire quality. The precise locating of the tire at the centre of the mold cavity involves exact positioning and movement of the tire grabbing elements/shoes of a chuck with respect to the central axis of a chuck mechanism assembly. This is done by radial independent adjustments on the shoes relative to the chuck central axis. The chuck mechanism assembly is furthermore intended to handle a range of bead sizes for the different tire sizes. Hence, it is very much essential for a chuck mechanism assembly to have its shoes adjusted in radial direction to achieve precise concentricity of the chuck over the entire range. Thus, besides moving the shoes radially inward and outward and grabbing and placing the tire along its upper bead, the chuck mechanism assembly has the above responsibilities.
Specifically, US Patent No.4580958 discloses a loader for a tire curing press comprising a support, a loader frame mounted to the support for vertical and horizontal movement, a loader basket mounted to the loader frame for engaging, holding and releasing a tire, a first actuator for vertically moving the loader frame, a second actuator for horizontally moving the loader frame into and out of the press when open, and a mechanical guide for guiding the loader frame from an over-center position in the press to a center position as the loader frame is moved vertically in the press. The loader frame is supported on a spline shaft for movement therealong and rotation therewith by ball bushings riding in the grooves of the spline split. The loader basket comprises a plurality of generally radially movable shoes, an adjustable stop for limiting radial movement of each shoe and an adjustment mechanism for simultaneously and uniformly adjusting the adjustable stops.

Another US Patent No. 4279438 discloses a loader for tire machinery such as tire press. The loader is supported from a vertically and horizontally movable frame and which includes a vertical shaft or sleeve journaled with respect to the frame with a horizontal plate secured for rotation therewith. Loader shoes are mounted on the frame for radial movement and respective links interconnect the plate and each loader shoe, each link extending at a common angle with respect to a radius from the center of rotation of the plate, and rotation of the plate in one direction will reduce the angle accordingly moving the shoes radially outwardly and rotation of the plate in the opposite direction will increase the angle moving the shoes radially inwardly. Each link is adjustable in length and the extent of rotation of the plate in one or both directions is limited by adjustable stops. The loader shoes remain parallel throughout their movement and are supported for radial movement by self-aligning slider blocks.
Yet another US Patent No. 4547012 discloses a tire loader. The tire loader has a support defining an upright axis and at least three like abutments angularly equispaced about and radially equispaced from the axis on the support. A plate pivotal about the axis on the support within the abutments carries at least three respective inner pivots angularly equispaced about and radially equispaced from the axis on the plate. At least three respective arms each have radially inner ends pivoted on the respective pivots and outer ends. Each arm bears angularly on the respective abutment. At least three respective bead-engaging shoes are pivoted on the outer ends of the respective arms. An actuator operatively connected between the support and the plate can rotate the plate about the axis on the support and thereby pivot the arms about the inner pivots and move the shoes radially. The abutments are rollers having respective roller axes parallel to the support axes. Each of the arms is displaceable between an inner position extending generally tangentially of the axis and with its inner end closely juxtaposed

with the outer end of the trailing arm and an outer position extending radially outward and forming an acute angle with a radius drawn from the axis through the respective inner pivot.
Still another US Patent No. 4401422 discloses a chuck assembly for use in a loader of a tire vulcanizer including a ring-shaped chuck main casing having an inner cylinder of a bore long enough to allow entry of a press center mechanism including a center post, a bladder and so forth, an outer cylinder concentrically surrounding the periphery of the inner cylinder and an upper cover connecting the inner and outer cylinders, rails radially aligned between the inner and outer cylinders in the main casing, a plurality of chucking paddles held by sliders slidably extending on a respective one of the rails for movement along the rails, and a ring-shaped chuck cam rotatably disposed about a rotational axis of the inner cylinder in the chuck main casing, wherein slider shafts of one of the respective paddles are slidably engaged with working cam grooves radially aligned in the chuck cam.
One more US Patent Application No. 2010/0159048 discloses a loader basket for gripping, transporting, and releasing tires, including a fixed ring, a rotating ring operatively interrelated with the fixed ring, a plurality of shoe arms pivotally attached to the fixed ring, shoe assemblies pivotally mounted on each of the shoe arms, alignment links pivotally mounted on the fixed ring and pivotally attached to each of the shoe assemblies, shoe arm actuating rods pivotally attached to each of the shoe arms and the rotating ring for pivoting the shoe arms about the fixed rings while maintaining the shoe assemblies in concentric relation during movement between collapsed and expanded positions, and an actuator for selectively moving the rotating ring relative to the fixed ring.

The chuck mechanism of the prior art has limitation that the engaging and disengaging of the tires using complex mechanisms having large number of interconnected links, hinders repeatability and position accuracy of the process. Further, the chuck mechanism of the prior art requires substantial amount of vertical space associated which creates clearance problems and increases the tire curing press open height. Furthermore, the increased number of links increases the manufacturing cost and loader/unloader gross weight, and has difficulty in assembling and disassembling and servicing the assembly. Moreover, owing to the increased operation frequency, the sliding parts of the loading/unloading mechanism exhibits more wear, which cannot be controlled by providing lubrication since the lubricant gets dried up by the hot temperature around the press, and also any leakage of lubricant on green tire may lead to scrap the tire, hence it results in frequent replacement at concerned regions.
Accordingly, there exists a need to provide a chuck assembly for a tire loader which overcomes drawbacks of the prior art.
Objects of the invention
An object of the present invention is to provide a simpler, compact and less weight chuck assembly for loader and unloader in a tire curing press for grabbing an uncured tire from a conveyor/tire holder and placing it on to a center mechanism of the tire curing press prior to the closing of the tire curing press and commencement of the curing cycle and to unload the finished tire from centre mechanism to conveyor.
Another object of the present invention is to provide a chuck assembly with repeated accuracy over the cycle of operations.

Another object of the present invention is to reduce the vertical height of the loader/unloader device chuck which creates clearance problems with the press cavity and increases the tire curing press open height.
Yet another object of the present invention is to reduce number of links in the loader/unloader device chuck assembly of the tire curing press which increases the manufacturing cost and loader/unloader gross weight, and reduces its reliability.
Yet another object of the present invention is to provide a chuck assembly which can be adjusted over the required bead ranges maintaining paddle concentricity with chuck assembly with simple and less time consuming process.
Yet another object of the present invention is to provide a plurality of linear movable paddles on a radially milled slot on a circular plate with less number of interconnected parts.
Yet another object of the present invention is to provide linear paddle movement through a relative motion between two cam plates through an actuator.
Still another object of the present invention is to provide chuck paddles with independent radial adjustments to ensure individual chuck paddle concentricity with chuck centre in case of paddle expanding and collapsing.
Yet another object of the present invention is to provide a chuck assembly with paddles, whose linear movement is aided with cam-follower combination which in turn reduces friction during movement through cam followers.

Still another object of the present invention is to provide a chuck assembly with no difficulty in assembling, disassembling and servicing of the loader/unloader device of the tire curing press.
Yet another object of the present invention is to provide a chuck assembly with lubrication free components, to reduce the maintenance and servicing cost of the assembly
Summary of the invention
Accordingly, the present invention provides a chuck assembly in loader and unloader of a tire curing press. The chuck assembly comprises a circular plate having a plurality of radially milled slots configured thereon. Further, the chuck assembly comprises a plurality of sliding shoes oriented with respect to the radially milled slots of the circular plate. Each sliding shoe of the plurality of sliding shoes includes a first cam follower, a second cam follower and a a third cam follower. Furthermore, the chuck assembly includes a connector disc having an across flat portion at its end, the across flat projection accommodating the first cam follower and the second cam follower, horizontally on its either side, for sliding on the circular plate along the radially milled slots on the circular plate, and having the third cam follower placed vertically on the across flat portion along the axis of the connector disk. Moreover, the chuck assembly includes a tire grabber plate connected to the connector disc. The tire grabber plate is capable of being adjusted to the connector disc for required level of sliding shoe concentricity with chuck centre.
Also, the chuck assembly includes a pair of sliding cam plate symmetrically positioned on the circular plate spacing the sliding shoes there between.

Each sliding cam plate includes a plurality of cam slots configured thereon and at least two guide cam slots arranged perpendicularly and symmetrically on the sliding cam plate.
The chuck assembly further includes a path guider assembly at each of the guide cam slots. The path guider assembly includes a cam block attached to the circular plate, a path tracing cam follower placed vertically on the cam block and following the guide cam slot, and thereby allowing the sliding cam plate to move towards/away from chuck centre horizontally, anda grabber cam follower placed horizontally on the cam block and sliding on the sliding cam plate and grabbing vertical movement of the sliding cam plate,
Brief description of the drawings
Figure 1 shows a top view of a loader/unloader device in accordance with the present invention;
Figure 2 shows sectional view of the loader/unloader device of figure 1;
Figure 3 shows a perspective view of shoe of the loader/unloader device of figure land 2;
Figure 4 and 5 shows a path guider of the loader/unloader device of figure 1 and 2;
Figure 6 shows a chuck assembly with the loader/unloader device in collapsed/closed condition; and

Figure 7 shows a chuck assembly with the loader/unloader device in open/expanded condition.
Detailed description of the invention
The foregoing objects of the present invention are accomplished 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 embodiments.
The present invention provides a chuck assembly in loader and unloader of a tire curing press. The chuck assembly is formed by a circular plate, a plurality of sliding shoes, a pair of sliding cam plate and a pneumatic cylinder which automatically grabs an uncured tire from the conveyor/tire holder and places it on to a center mechanism of the tire curing press prior to the closing of the tire curing press and commencement of the curing cycle. Further, the chuck assembly picks up the cured tire from the center mechanism after the tire curing, press opens and the curing cycle is competed and places it on the conveyor belt. The chuck assembly of the present invention is innovative and entirety differing from the existing mechanisms.
Referring now to figure 1 and 7, there is shown a chuck assembly [100) in loader and unloader of a tire curing press, in accordance with the present invention. The chuck assembly [100] includes a circular plate (10), a plurality of sliding shoes (20), a pair of sliding cam plate (30), and a pneumatic powered cylinder (40).
The circular plate (10), alternatively know as the circular mounting plate (10) includes an outer shell member (12) configured thereon. The circular

mounting plate (10) and the outer shell member (12) are welded at an inner race of the shell member (12) to an outer race of the circular mounting plate (10) over the circumference to form an assembly (14). The circular mounting plate (10) and the outer shell member (12) are connected to a support arm (50). Specifically, the outer shell member (12) is provided with mounting provision at its tail end to integrate it with the support arm (50) through fastener arrangement (52). Further, the support arm (50) includes an outer end pivoted on an annular support ring centered on an axis and its inner end supports the assembly (14) through fastening arrangement (52). Specifically, the support arm (50) and the assembly (14) have a set vertical and horizontal movement in a conventional manner.
The circular mounting plate (10) includes a plurality of radially milled slots (16) configured thereon. Each slot of the plurality of radially milled slots (16) is arranged at an angle of 45° apart with other slot. Specifically, the plurality of radially milled slots (16) starts from a predefined position from the circular mounting plate's (10) inner race, proceeding over a predefined length.
The plurality of sliding shoes (20) is oriented with respect to the radially milled slots (16) of the circular mounting plate (10). Each sliding shoe (20) is an assembly of three cam followers (22) - a first cam follower (22a), a second cam follower (22b) and a third cam follower (22c), a connector disc (24), and a tire grabber plate (26). The first cam follower (22a) and the second cam follower (22b) are placed horizontally opposite to each other separated by a small distance, on to the connector disc (24). The first cam follower (22a) and the second cam follower (22b) achieve radial sliding movement on the circular mounting plate (10) and share the tire weight. The third cam follower (22c) is placed vertically on to the centre axis of the connector disc (24).

The connector disc [24] is a circular part with across flat portion at its one end which accommodates the first cam follower (22a) and the second cam follower (22b). The across flat portion at its one end allows the connector disc (24) to slide with clearance, within the radially milled slots (16) on the circular mounting plate (10).
The tire grabber plate (26) is plate mounted vertically with the connector disc (24). The tire grabber plate (26) includes a curved outer surface for contacting with a tire bead inner race. The tire grabber plate (26) further includes an angular projection at its lower end, to grab the tire. The tire grabber plate (26) is provided with an extended flat face at its top end along with a pair of horizontal circular end slot (26a) configured thereon. The horizontal circular end slots (26 a) provide for adjusting the tire grabber plate (26) radially in/out in an independent manner to the required level of sliding shoe concentricity with chuck centre. The tire grabber plate (26) is attached to the sliding shoe (20) by fastening the tire grabber plate (26) with the connector disc (24) through two fasteners (26b) at the flat faced end's horizontal circular end slots of the tire grabber plate (26).
The pair of sliding cam plate (30) is symmetrically positioned on the circular mounting plate (10) spacing the plurality of sliding shoe (20) there between. Each sliding cam plate (30) includes a plurality of radially extending cam slots (32) located in a predefined manner which are controlled by angular variation with respect to each other. Each sliding cam plate (30) further includes two guide cam slots (34) milled vertically and placed symmetrically on the sliding cam plate (30). The sliding cam plate (30) is symmetrically placed on to the circular mounting plate (10).
The circular mounting plate (10) and the sliding cam plate (30) are coupled together by spacing the plurality of sliding shoe (20) in a manner such that

the across flat surface of the connector disc (24) get inside the radially milled slots (16) on the circular mounting plate (10) and the first cam follower (22a) and the second cam follower (22b) slide on the circular mounting plate (10). Further, the third cam follower (22c) of the sliding shoe (20) gets inside the radially extending cam slots (32) on the sliding cam plate (30) such that a correlation exists between the circular mounting plate (10), the sliding shoe (20) and the sliding cam plate (30). When the sliding cam plate (30) is pushed outward/pulled inward in horizontal direction, the three cam followers (22a. 22b and 22c) follow the resultant path given by the combination of the radially milled slots (16) of the circular mounting plate (10) and the radially extending cam slots (32) of the sliding cam plate (30).
The resultant path given by the aforesaid combination of the radially milted slots (16) and the radially extending cam slots (32) moves the plurality of sliding shoes (20) radially outward thereby pushing out the sliding cam plate (30) and radially inward while pulling in the sliding cam plate (30). With the combination of the plurality of sliding shoes (20), a grabbing and relieving (expanding and collapsing) mechanism of the chuck assembly (100) is obtained.
The sliding cam plate (30) is pushed out and is pulled in with the help of a pneumatic powered cylinder (40). The pneumatic powered cylinder (40) is connected to the sliding cam plate (30) through connector pins (42). The connector pins (42) are attached to the sliding cam plate (30). Further, the connector pins (42) are attached to a connector link (44) which in turn is connected to the pneumatic powered cylinder (40). Each sliding cam plate (30) is guided by two path guiders assemblies (46) (total four path guider assemblies) located symmetrically on the four quadrants of the circular mounting plate (10).

The path guider assembly (46) consists of a set of two cam followers, for example, a path tracing cam follower (46a) and a grabber cam follower (46b) fastened with a cam block (46c). The cam block (46c) is attached to the circular mounting plate (10) by means of welding. The path tracing cam follower (46a) is placed vertically on the cam block (46c) which follows the vertical guide cam slots (34) provided on the sliding cam plate (30). The cam block (46c) allows the sliding cam plate (30) to move in/out horizontally. Further, the grabbing cam follower (46b) is placed horizontally on the cam block (46c). The grabbing cam follower (46b) slides on the sliding cam plate (30) surface and grab the sliding cam plate (30) from moving vertically up when it is being pushed and pulled by the pneumatic cylinder (40).
The chuck assembly (100) includes a vertical mount (60) for mounting the pneumatic powered cylinder (40). The vertical mount (60) is fastened to the circular mounting plate (10) by fasteners (62). The pneumatic powered cylinder (40) encloses an adjusting rod (64) fixed to the vertical mount (60) for controlling throw of the pneumatic cylinder (40). Further, a stopper (66) is provided on an end of the pneumatic powered cylinder (40) for controlling the throw thereof. The throw of the pneumatic powered cylinder (40) is adjusted by adjusting the stopper (66) impact location on a nut (64a) of the adjusting rod (64). The rod end of the pneumatic powered cylinders (40) also consists of a pivot plate (68) with pivot pins (68a), pivoting the connector link (44) to the connector pin (42) at the sliding cam plate (30).
Thus by powering the pneumatic cylinder (40), the rod end extends and the connecting link (44) expands by pushing the sliding cam plate (30) out , through connector pin (42). The sliding cam plate (30) is guided by the path

guider assembly (46) for its horizontal movement. Thereafter, the plurality of sliding shoes (20) expands radially out maintaining the concentricity thereof with the cam slots combination, exhibiting the grabbing mechanism for grabbing the tire,
Further, when the pneumatic cylinder (40) retracts, the connector links (44) are pulled in through the connector pins (42) and the sliding cam plate (30) moves in horizontally, as a result of which the plurality of sliding shoes (20) moves radially in maintaining the concentricity thereof with the cam slots combination, exhibiting the relieving mechanism for placing the tire.
Accordingly, the present invention provides a simpler chuck mechanism with a minimum number of components and less weight which is cost effective. The chuck assembly (100) avoids many interconnected links, which in turn forms an easy to assemble, disassemble and serviceable chuck mechanism, The vertical height of the chuck assembly (100) has also brought down which brings down the press open height. The chuck assembly (100) can be adjusted over the range of bead sizes for different tire sizes with ease. Also the use of a total of thirty six lubrication/maintenance free cam followers benefits the chuck assembly (100) with a smooth and precise movement of sliding shoes radially in/out with accuracy maintained over the cycle of operations. This also overcomes the friction caused due to surface contact while sliding of shoes (20) in case of existing mechanisms by the point contact of cam followers, as a result of which the wear rate of components is drastically reduced giving way to a reliable, maintenance free and rigid chuck mechanism. Further, the chuck assembly (100) gives precise positioning of uncured tire on to the centre mechanism of the press, by having the option to radially adjust the shoe independently and thereby having a good repeatability.

Advantages of the Invention:
1. The chuck assembly (100) is very simple , compact and light in weight when compared with existing arrangements.
2. The chuck assembly [100) gives accurate concentricity of the sliding shoes with the chuck center through independent radial adjustment of sliding shoes assembly.
3. In the chuck assembly (100), the plurality of cam followers ensures minimum friction with much reduced components wear thereby avoiding frequent replacement of worn out parts and also provides repeatable accuracy.
4. The chuck assembly (100) can be easily adjusted for any bead size within its design specifications with simple adjustments at less time.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A chuck assembly in loader and unloader of a tire curing press, the chuck assembly comprising:
a circular plate having a plurality of radially milled slots configured thereon;
a plurality of sliding shoes oriented with respect to the
radially milled slots of the circular plate, each sliding shoe of the
plurality of sliding shoes having a first cam follower, a second cam
follower, and a third cam follower;
a connector disc having an across flat portion at its end, the across flat projection accommodating the first cam follower and the second cam follower, horizontally on its either side, for sliding on the circular plate along the radially milled slots on the circular plate, and having the third cam follower placed vertically on the across flat portion along the axis of the connector disk;
a tire grabber plate connected to the connector disc, the tire grabber plate being capable of being adjusted to the connector disc for required level of sliding shoe concentricity with chuck centre;
a pair of sliding cam plate symmetrically positioned on the circular plate spacing the sliding shoes therebetween, each sliding cam plate having a plurality of cam slots configured thereon and at least two guide cam slots arranged perpendicularly and symmetrically on the sliding cam plate; and
a path guider assembly at each of the guide cam slots, the path guider assembly having,
a cam block attached to the circular plate,

a path tracing cam follower placed vertically on the cam block and following the guide cam slot, and thereby allowing the sliding cam plate to move towards/away from chuck centre horizontally, and
a grabber cam follower placed horizontally on the cam block and sliding on the sliding cam plate and grabbing vertical movement of the sliding cam plate,
wherein when the pair of sliding cam plate is pushed outward/pulled inward in horizontal direction, each of the first cam follower, the second cam follower and the third cam follower follows a path given by the combination of the radially milled slots on the circular plate and the radial slots on the sliding cam plate thereby moving the sliding shoe radially outward while pushing out the sliding cam plate and radially inward while pulling in the sliding cam plate thereby maintaining the concentricity of the sliding shoes with the chuck assembly centre while loading/unloading tire.
2. The chuck assembly of claim 1 wherein the circular plate further comprises an outer shell member, the circular plate and the outer shell member connected to a support arm.
3. The chuck assembly of Claim 1 wherein each slot of the plurality of radially milled slots is arranged at an angle of 45° with adjacent slot.
4. The chuck assembly of Claim 1 wherein the pair of sliding cam plate is pushed outward/pulled inward in horizontal direction by pneumatically powered piston connected to each of the sliding cam plates through a connector link.
5. The chuck assembly as claimed in Claim 1, wherein the tire grabber plate is provided with an extended flat face at its top end along

with a pair of horizontal circular end for adjusting the tire grabber plate independently radially in/out to the required level of concentricity with the chuck centre.