Conveyor roller assembly, use thereof and end cap for conveyor roller

Abstract

The present invention relates to a conveyor roller assembly suitable for use in environments subject to important temperature changes, and to an integrated end cap. The integrated end cap ensures an effective torque transfer to the ceramic cartridge due to its elasticity caused by deformation of the end cap during assembly of the end cap on the ceramic cartridge.

Description

[0001] This application is a divisional application of an invention patent application with an international application date of March 30, 2017, an international application number of PCT / EP2017 / 057609, a national application number of 201780021535.9, and an invention name of “Conveyor roller assembly, its use, and end cover for conveyor roller”.

[0002] The present invention relates to a conveyor roller assembly suitable for use in environments subject to significant temperature variations, to the use of such an assembly, and to improved end caps that can be used in such an assembly.

[0003] Conveyor roller assemblies suitable for use in environments subject to significant temperature variations may include a ceramic spool with metal end caps. Typically, the ceramic spool contains fused silica. The end caps allow for easy mounting to bearings or drive wheels. For example, in glass tempering applications, a series of ceramic spools support a sheet of glass, and the end caps thus allow for mechanical coupling to a drive mechanism. The end caps should be securely attached to the spool, allowing the spool to rotate at the desired speed.

[0004] The different thermal expansion of the ceramic valve core and the metal end cap makes it difficult to securely fasten the end cap to the valve core and may cause eccentric rotation or breakage when heated or cooled. Eccentric rotation is generally undesirable because it creates an uneven support surface for the glass sheet or speed changes that cause scratches. A variety of methods have been proposed to overcome this difficulty. U.S. Patent No. 3,867,748 proposes the use of an adhesive to fasten the end cap to the valve core. U.S. Patent No. 4,242,782 proposes the use of a rubber O-ring to fasten the end cap. Adhesives and O-rings can become pliable and lose their holding power at high temperatures, resulting in eccentric rotation of the valve core and slippage between the end cap and the valve core. If the adhesive and O-ring are accidentally subjected to such high temperatures, they will certainly lose their holding power so that even if the temperature returns to its normal value, slippage will still be observed. Therefore, the use of adhesives or O-rings to fasten the end cap to the valve core is limited to applications at low temperatures (less than 250°C).

[0005] Metal connectors have also been used to secure the end cap to the valve core. U.S. Patent No. 5,316,129 or U.S. Patent No. 4,404,011 describe the use of a spirally wound coil between the valve core and the end cap. The coil includes a curved portion and a straight portion that allow continuous contact between the end cap and the valve core having different thermal expansion coefficients. The planar spring coil of this document is composed of a relatively long and relatively thin continuous portion. Under these conditions, a significant flexibility of the coil element is observed. Therefore, in order to obtain a torque sufficient to secure the end cap to the valve core, it is necessary to pre-stress the coil very significantly. If the temperature rises unexpectedly (temporary overheating), the torque is lost, and therefore the fastening of the end cap to the valve core is also lost. In addition, the torque does not recover when the system cools down. U.S. Patents No. 5,906,567 and No. 5,370,596 describe curved bimetallic gaskets for securing the end cap to the valve core. The curvature of the bimetallic gasket changes with temperature, thereby maintaining a firm attachment between the valve core and the end cap. However, coil springs or bimetal systems can be difficult to assemble and repair. In addition, such metal connectors are particularly suitable for a certain temperature range (usually 400°C and higher). Outside this range, eccentric rotation can be observed.

[0006] Another problem often observed in prior art conveyor rollers is the problem of clogging. For example, in the event of a blockage of the conveyed product or in the event of a mechanical jam, the drive mechanism will continue to operate and transmit a torsional moment to the end cap. Under these conditions, the ceramic valve core or the fastening device will break.

[0007] EP-B1-1853866 solves these problems by providing a conveyor roller assembly comprising an end cap with a tolerance ring which is interposed between the end cap and the end of the ceramic valve core and secures the end cap securely and centrally to the ceramic valve core over a wide range of application temperatures. Since the transmitted torque value can decrease over time at high temperatures, these end caps provide a range of transmitted torques up to several hundred Nm and resist temporary overheating. However, these end cap systems are oversized most of the time.

[0008] Other disadvantages of end caps including tolerance rings are that they are made of at least two separate parts requiring assembly steps and are relatively expensive due to the size and design of the end cap.

[0009] DE-A1-10, 2011, 084, 218 discloses an end cap for a bearing roller having a ceramic roller body. The end cap comprises an end of a shaft for rotatable support and a receiving portion for the roller body. The receiving portion is formed by at least two segments separated by a hole and is formed integrally with a connecting plate. The segment has a conical contact surface to cooperate with an adjustable actuating element that also has a conical contact surface. The segment has an inwardly protruding extension that fits in the groove of the roller body and hinders the relative rotation between the roller body and the end cap. The torque is transmitted by using a conical ring that fastens the end cap to the valve core. The torque transmission is achieved by contact pressure rather than by friction. The disadvantages of this end cap are as follows: the end cap is made of at least 3 components (end cap, nut, conical ring), and each roller must be specifically fastened at both ends. In addition, the thickness of the end cap is quite important to ensure good fastening. Then, the end cap must be installed outside the wall of the oven, so that the valve core has a longer overall length.

[0010] GB-A-2,051,034 describes an assembly of a valve core and an elastic sleeve which is rotated by laying the assembly on an annular belt. The entire surface of the sleeve is used to transmit torque, while pins are required to prevent lateral movement of the valve core. Since the sleeve must be located outside the furnace wall, the length of the valve core must be longer to span the furnace wall. The sleeve is indeed not elastic enough to withstand important temperature changes. Installation is also cumbersome.

[0011] A new end cap has been developed that solves the above problems and has the advantage of being simpler and cheaper to assemble than the end caps described in EP-B1-1853866 and DE-A1-10,2011,084,218. The new end cap ensures an effective torque transmission from the rotary drive to the ceramic valve core, thanks to its elasticity caused by the deformation of the end cap during assembly of the end cap on the ceramic valve core. In fact, the inventors have determined that a minimum transmitted torque value is sufficient to rotate the roller for the application and that the assembly according to the invention is able to provide this minimum transmitted torque value.

[0012] Due to the symmetry of the end cap, the contact between the end cap and the ceramic valve core is evenly distributed even at higher temperatures. The ceramic valve core remains completely coaxial with the end cap.

[0013] Another advantage of this new end cap is its thin thickness. A thickness of only 1 mm to 5 mm can be used. The end cap can then be installed in the wall of the oven so that the ceramic valve core has a shorter required length.

[0014] The present invention relates to a conveyor roller (1) assembly suitable for use in environments subject to significant temperature variations, the conveyor roller assembly comprising:

[0015] a) A ceramic valve element (2) having a longitudinal axis; b) A metal end cap (3) at least at one end of the ceramic valve element, the metal end cap including a first end (4) connectable to a rotating device and a second end, the second end including:

[0016] An integral body having two ends, an inner diameter D adapted to fit the end of the ceramic valve element, and a length L greater than 0.3D or preferably greater than 0.5D.

[0017] The integral body includes at least three continuous portions along the longitudinal axis of the integral body. The two end portions of the integral body include substantially continuous surfaces and a torque transmission portion therebetween.

[0018] The torque transmission portion includes a plurality of openings (6) having a length Lb < L in the longitudinal axis direction of the body. The plurality of strips (7) defined between the openings extend inwardly and are mechanically deformable and elastically deformable to transmit torque to the valve element.

[0019] Openings are required to obtain an elastically deformable portion for transmitting torque to the valve element. Longitudinal openings are preferred.

[0020] The length (L) of the second end of the end cap is at least greater than 0.3D, preferably at least greater than 0.5D; D is the inner diameter measured at the end of the metal end cap that houses the ceramic valve element. In fact, the end cap must correctly guide the valve element even during temporary overheating and must keep the valve element coaxial with the end cap. Too short a length will also reduce the desired elastic properties of the end cap.

[0021] The openings can have different shapes, with a rectangular shape being preferred because it is easy to manufacture. The resulting strips have a rectangular shape that makes it easier to dimension the end cap. For each different ceramic valve element, calculations are performed on the stresses and deformations generated in the end cap to determine the size of the openings. The openings preferably have the same length and are parallel to the longitudinal axis of the ceramic valve element. These openings are also preferably evenly distributed over the entire circumference of the second end of the end cap. The combination of these feature portions and the strip feature portions optimizes the distribution of stresses caused by the deformation of the end cap during the assembly of the ceramic valve element and during temperature changes.

[0022] The shape of the strip is defined by the shape of the opening.

[0023] These strips extend inwards in the direction of the ceramic valve core. In one embodiment, at least one strip has a thicker portion. In a preferred embodiment, all strips have a thicker portion to increase the transmitted torque value. The inner diameter of the end cap thus decreases in a local area, thereby tensioning the strips and enhancing the contact with the ceramic valve core. The thicker portion is preferably located in the middle of the strip. As described above, this makes it easier to determine the size of the cap. In addition, the ratio of stress to deformation is optimized. As the temperature rises, the end cap thermally expands while the size of the ceramic valve core does not change significantly. Therefore, the fastening force of the end cap decreases and the valve core begins to slip within the end cap. When the temperature returns to normal, the end cap will return to its "normal" size and the holding force will be restored as a whole without causing eccentric rotation.

[0024] The conveying roller according to the present invention can be used to convey foil or sheet (e.g., foil or sheet of glass or metal) products for any type of heat treatment of the foil or sheet or the coating applied thereon. This conveying roller is particularly suitable for transporting flat-bottomed products in an environment that undergoes significant temperature changes.

[0025] The ceramic valve core (2) generally contains materials suitable for high-temperature applications, preferably fused silica, mullite or sillimanite.

[0026] The present invention also relates to a one-piece metal end cap in a conveying roller assembly for an environment that undergoes significant temperature changes. The one-piece metal end cap has a longitudinal axis and includes a first end and a second end that can be connected to a rotating device. The second end includes:

[0027] A one-piece body having two ends, an inner diameter D suitable for fitting the end of the ceramic valve core, and a length L > 0.3D or preferably > 0.5D. The one-piece body includes at least three continuous portions along the longitudinal axis of the one-piece body. The two end portions of the one-piece body include substantially continuous surfaces and a torque transmission portion between these portions. The torque transmission portion includes a plurality of openings with a length Lb < L in the direction of the longitudinal axis. A plurality of strips defined between the openings extend inwards and can be mechanically deformed and elastically deformed to transmit torque to the valve core.

[0028] The first end of the end cap is connected to the drive system by, for example, a belt or a gear. The openings are made by conventional machining devices or lasers. The strips obtained with respect to the openings have a thicker portion also made by conventional machining devices. The thicker portion extends inwards and preferably has the shape of a raised surface between two inclined surfaces.

[0029] Although a strip processing step is required, the metal end cap is lighter and cheaper than the end cap of EP-B1-1853866.

[0030] The invention will be better understood from reading the following description, which is given by way of example only and is made with reference to the following drawings:

[0031] Figure 1 is a perspective view of an assembly of a conveyor roller according to one embodiment of the present invention,

[0032] Figure 2 is a perspective view of an end cap of an assembly according to one embodiment of the present invention,

[0033] Figure 3 yes Figure 2 A cross-sectional view of the end cap.

[0034] Figure 1 The conveying roller assembly (1) according to the present invention includes a ceramic valve core (2) and two metal end caps (3). The length L represents the length of the second end (5) of the end cap, as shown in FIG. Figure 2 shown. Figure 3 An internal view of the end cap is shown. The thicker portion (8) is the portion having two slopes leading to the raised floor.

[0035] Reference Numbers List

[0036] 1.Conveyor roller assembly

[0037] 2. Ceramic valve core

[0038] 3.Metal end cap

[0039] 4. The first end of the metal end cap

[0040] 5. The second end of the metal end cap

[0041] 6. Vertical opening

[0042] 7. Strip

[0043] 8. The thicker part of the strip

Claims

1. An integral metal end cap (3) for a conveying roller assembly, the conveying roller assembly being for use in an environment subject to significant temperature variations, the integral metal end cap having a longitudinal axis and comprising: a first end (4) and a second end (5) connectable to a rotating device, the second end comprising: an integral body having two ends, an inner diameter D of the end adapted to fit a ceramic valve core, and a length L greater than 0.3D or preferably greater than 0.5D, the integral body comprising at least three continuous portions along the longitudinal axis of the integral body, the two end portions of the integral body comprising substantially continuous surfaces and a torque transmission portion therebetween, the torque transmission portion comprising a plurality of openings (6) having a length Lb < L in the direction of the longitudinal axis, a plurality of strips (7) defined between the openings extending inwards and being mechanically deformable and elastically deformable during the assembly of the integral metal end cap onto the ceramic valve core and during temperature variations so as to transmit the torque to the valve core; wherein the size of the openings is adapted to the stresses and deformations generated in the integral metal end cap (3) such that the integral metal end cap provides a minimum transmitted torque value sufficient to rotate the conveying roller.

2. An integral metal end cap (3) for a conveying roller assembly, the conveying roller assembly being for use in an environment subject to significant temperature variations, the integral metal end cap having a longitudinal axis and comprising: a first end (4) and a second end (5) connectable to a rotating device, the second end comprising: an integral body having two ends, an inner diameter D of the end adapted to fit a ceramic valve core, and a length L greater than 0.3D or preferably greater than 0.5D, the integral body comprising at least three continuous portions along the longitudinal axis of the integral body, the two end portions of the integral body comprising substantially continuous surfaces and a torque transmission portion therebetween, the torque transmission portion comprising a plurality of openings (6) having a length Lb < L in the direction of the longitudinal axis, a plurality of strips (7) defined between the openings extending inwards and being mechanically deformable and elastically deformable during the assembly of the integral metal end cap onto the ceramic valve core and during temperature variations so as to transmit the torque to the valve core, the entire outer surface of the strip (7) being continuous, and the openings being rectangular.

3. The integral metal end cap according to claim 2, wherein the openings are longitudinal, have the same length and are parallel to the longitudinal axis of the ceramic valve core.

4. The integral metal end cap according to claim 2, wherein the openings are evenly distributed on the conveying roller.

5. The integral metal end cap according to claim 2, wherein the strips extending inwards comprise thicker portions (8).

6. The integral metal end cap according to claim 5, wherein the thicker portions of the strips are in the middle of the strips.

7. The one-piece metal end cap according to any one of claims 2 to 6, wherein the one-piece body has a thickness of 1 mm to 5 mm.

8. A conveyor roller (1) assembly suitable for use in an environment subject to significant temperature changes, the conveyor roller assembly comprising: a) a ceramic valve core (2) having a longitudinal axis; b) A metal end cap (3) according to any one of claims 1 to 7 at least at one end of the ceramic valve core.

9. The conveyor roller (1) assembly according to claim 8, wherein the ceramic valve core (2) comprises fused silica, mullite or sillimanite.

10. Use of the conveyor roller (1) assembly according to claim 8 for transporting flat-bottomed products in an environment subject to significant temperature changes.

Images