Latch mechanism for a forehearth feeder tube lift system

Abstract: A latch mechanism (80; 280) for releasably securing a clamping ring (86, 286) to a flange (24) which is to be moved in and out of an operating position, particularly of a feeder tube (22) in a glass melting forehearth installation. The latch mechanism comprises a fixing structure (88), a support member (84) and a lever (82, 282). The support member (84) is pivotally connected about a first axis (D) to the fixing structure (88), and carries a second axis (C). The lever (82, 282) has a cam (82b, 282b) and may be pivoted about the second axis (C) so as to engage the clamping ring (86, 286) and press it onto the flange (24) or to disengage said cam (82b, 282b) from said clamping ring (86, 286) and, together with said support member (84), swing about said first axis (D) to get out of the way and permit the clamping ring (86, 286) to be lifted out of engagement with the flange (24).

Description: Field of the Invention This invention relates to a latch mechanism for releasably clamping a flange of a feeder tube in a glass melting furnace forehearth installation in its operating position. Description of the Prior Art US-A 5,718,741 discloses a forehearth having a feeder bowl and a vertically extending, refractory feeder tube, the lowermost end thereof being immersed in the feeder bowl to a level slightly above the inside surface of the bottom of the feeder bowl and surrounding the opening(s) at the bottom of the feeder bowl. The feeder tube is caused to rotate slowly during the operation of the forehearth to ensure a proper mixing and temperature uniformity of the molten glass flowing from the feeder bowl. A feeder bowl refractory tube with a tube drive system is disclosed in US-A-5,660,610 (DiFrank). Other glass forehearth feeder bowl feeder tube arrangements are described in US-A-5,693,114, 4,514,209 and 4,478,631. From time to time during the operation of a glass manufacturing system of a type employing a forehearth feeder bowl feeder tube of the type described above, it is necessary to remove the feeder tube and/or the feeder bowl for repair or replacement. In the case of the replacement of the feeder bowl, the feeder tube must also be swung horizontally out of the way of the feeder bowl as well as being lifted vertically so that its lower edge clears the upper extent of the feeder bowl. It is also necessary from time to time to be able to adjust the height of the feeder tube. Also, from time to time, it is necessary to replace a feeder bowl itself. In the prior art, this required removal of the entire feeder tube mechanism itself. A feeder tube in apparatus of the type described is releasably held in place by a circumferentially spaced apart plurality of clamps. Heretofore, it has been difficult to release such clamps, which typically involved threaded members, because of the tendency of such members to corrode in the high temperature environment of a feeder tube installation and the need for workers to wear temperature resistant gloves during this procedure, gloves that are quite bulky. Summary of the Invention The problem of the invention is to provide a clamping system that can be handled also in difficult environments. This problem is solved by the features of claim 1. In a preferred application of the invention, there is provided an improved latch mechanism for releasably clamping a flange of a feeder tube in a glass melting forehearth by engaging a clamping ring which is pressed against the flange of the feeder tube. Each such clamp has a variable radius cam that is rotatable about a radially extending horizontal axis to make secure contact with the clamping ring regardless of the elevation of the feeder tube, but which is capable of being swung out of interfering contact with the feeder tube to permit the feeder tube to be removed for repair or replacement after first removing the clamping ring used to engage the flange of the feeder tube. The latch mechanism of invention is rapidly releasable in that it does not require threaded fasteners in its design or installation. For further understanding of the present invention and the objects thereof, attention is directed to the drawing and the following brief description thereof, to the detailed description of the preferred embodiment and to the appended claims. Brief Description of the Drawing Fig. 1 is a fragmentary elevational view of a feeder tube assembly incorporating a clamp down system; Fig. 2 is a plan view of the feeder tube assembly of Fig. 1; Fig. 3 is a sectional view taken on line 3-3 of Fig. 2; Fig .4 is a fragmentary perspective view of a portion of the feeder tube assembly of Figs. 1-3; Fig. 5 is a view similar to Fig. 4 illustrating a modified form of the apparatus illustrated therein; and Fig. 6 is a fragmentary perspective view of a feeder tube assembly that incorporates a plurality of the devices of Fig. 5. Detailed Description of the Preferred Embodiment A feeder tube assembly 20 includes a refractory feeder tube 22 which, as is shown in Fig. 3, is adapted to be inserted into a molten glass feeder bowl B at the outlet end of a generally horizontally extending molten glass cooling forehearth, otherwise not shown, which may be of conventional construction. The feeder tube 22 is vertically oriented in the feeder tube assembly 20, and its lowermost end is positioned slightly above the inside surface of the feeder bowl B, to thereby allow molten glass to flow through the space below the feeder tube 22 to exit through openings O at the bottom of the feeder bowl B. The feeder tube 22 has an outwardly projecting flange 24 at its upper end, and the flange 24 is clamped in a clamping ring subassembly 86, Fig. 3, which is provided with lifting eyes 18, Fig. 2, 3, 6, and serves to support the feeder tube 22 on an inwardly projecting flange 26 of a rotatable ring subassembly 28. The rotatable ring subassembly 28 is cantilevered at the end of a support arm 30, and the subassembly 28 includes an upwardly facing ring gear 32, Fig. 2, and is caused to rotate slowly with respect to the support arm 30 by the engagement of the ring gear 32 by a driven pinion 34 at an end of a driven rod 36, which is driven by a motor 38 acting through a speed reducer 40, all of which are supported on the support arm 32 at an end opposed to the end on which the feeder tube 22 is suspended. The rotation of the feeder tube 22 helps to properly mix the molten glass in the feeder bowl B to thereby ensure proper homogeneity and temperature uniformity of the molten glass exiting through the openings O, Fig. 3. The support arm 30 is supported along a vertically extending axis A that extends through a handle 42, which serves to lock the support arm. The support arm 30 is also adjustably supported for precisely controllable motion along the axis A on a vertically extending servo motor powered precision linear actuator 44, Fig. 1. Because of the high temperature environment in which the feeder tube 22 is used, it is important to cool the end of the support arm 30 from which the feeder tube 22 is suspended. To that end, an annular passage 72, Fig. 1, 3 is provided in the support arm 30 surrounding and extending generally concentrically of the feeder tube 22, and cooling air or other cooling fluid is caused to flow through the passage 72 from inlet and outlet lines 74, 76, respectively. Further, a generally semi-cylindrical heat shield 78 is suspended form the support arm 30 at a location partly surrounding the upper end of the linear actuator 44, and between the linear actuator 44 and the feeder tube 22, to retard heating of the linear actuator 44 by heat radiated from the feeder bowl B. The flange 24, Fig. 3, of the feeder tube 22 is securely, but releasably, held in engagement with the flange 26 by a plurality of circumferentially spaced apart latch mechanisms, each generally identified by reference numeral 80, Fig. 2, three such latch mechanisms being shown in Fig. 2. Each latch mechanism 80 comprises a lever 82, Fig. 3, 4 with a handle portion 82a at an end thereof and an enlarged cam portion 82b at an opposed end. The lever 82 is pivotably connected to a support member 84 about an axis C and, when the lever extends vertically, the cam portion 82b securely engages an upper surface of the clamping ring 86 which engages the flange 24 of the feeder tube 22 to forcibly press the flange 24 into its desired operating position. When the lever 82 is pivoted to a horizontal orientation, the cam portion 82b no longer engages the ring 86, Fig. 4. In this position, the feeder tube 22 may be removed from the feeder bowl B by a simple lifting motion, using the lifting eyes 18, Figs. 2 and 6. The latch mechanisms 80 are moveable out of alignment with the feeder tube 22 by pivotably connecting the support member 84 to a fixed structure 98 about an axis D. In that regard, the support member 84 is slidable toward an enlarged area 88a of the fixed structure 88, where it can then be pivoted about the axis D out of interfering relationship with the clamping 86. Before installing a new feeder tube 22, the support arm 30 should be elevated so that the new feeder tube 22 does not contact the feeder bowl B. The pivoting of the support arm 30 about the axis A is done when it is desired to replace a feeder bowl B. After releasing the feeder tube 22 from its engaged position by the release of the latch mechanisms 80, as heretofore described, and after the actuation of the linear actuator 44 to lift the support arm 30 to an elevation such that the bottom of the feeder tube 22 is free of the feeder bowl B, the feeder tube 22 is then hoisted from the subassembly 28. In Figs. 5 and 6 elements that differ from, but correspond in function to, elements of the embodiment of Fig. 1-4 are identified by 200 series reference numerals, the last two digits of which are the two digits of the corresponding element of the embodiment of Figs. 1-4. Fig. 5 illustrates a latch mechanism 280, and three such latch mechanisms 280 are illustrated in 11 Fig. 6 in circumferentially spaced apart relationship to one another. Each latch mechanism 280 comprises a lever 282 with a handle portion 282a at an end thereof and an enlarged cam portion 282b at an opposed end, the handle portion 282a extending from a position that is between the ends of the cam portion 282b whereas the handle portion 82a of the lever 80 of the embodiment of Fig. 4 is aligned with an end of the cam portion 82b. In that regard, the cam portion 282b of the lever 282 has a profile that is more universally applicable to various installations than is the profile of the cam portion 82b of the lever 82 because of variations in the thickness of the flange portion 24 of the feeder tube 22 from installation to installation. The lever 282 is pivotally connected to a support member 84 about an axis and when the lever 282 extends vertically, the cam portion 282b securely engages a recessed bottom in a notch 286a of a clamping ring 286, which engages the flange 24 of the feeder tube 22 to forcibly press the flange 24 into its desired operating position. The use of the notch 286a in the clamping ring 286 facilitates better engagement of the clamping ring 286 by the cam portion 282b of the lever 282, and it also facilitates easier release of the clamping action of the lever 280 when it is desired to change the feeder tube 22 when the lever 282 is pivoted to a horizontal orientation, the cam portion 282b no longer engages the clamping ring 286. In this position, the clamping ring 286 may be lifted out of position, as is shown in phantom in Fig. 6, to thereupon permit the feeder tube 22 to be lifted out of position, it first being necessary to move each of the latch mechanisms 280 out of interfering alignment with the clamping ring 286 and the feeder tube 22. This is done by sliding the support member 84 to the enlarged area 88a of the fixed structure 88 and then by pivoting the support member 84 about the axis D out of interfering relationship with the clamping ring 286.

Claims: A latch mechanism (80; 280) for releasably securing a clamping ring (86, 286) to a flange (24) of a feeder tube (22) in a glass melting forehearth installation which is to be moved in and out of an operating position, the latch mechanism comprising: a fixing structure (88) for fixing the latch mechanism (80; 280); a support member (84) having one end pivotally connected about a first axis (D) to said fixing structure (88) and a second end provided with a second axis (C); and a lever (82, 282) which is pivotally connected through said second axis (C) to said support member (84) and includes a handle (82a, 282a) and a cam (82b, 282b) with a rounded cam surface, said lever (82, 282) allowing to engage the clamping ring (86, 286) by the rounded cam surface and press the clamping ring (86, 286) onto the flange (24) so as to take its operating position, said lever (82, 282) also allowing to disengage said cam (82b, 282b) from said clamping ring (86, 286) and, together with said support member (84), swing about said first axis (D) to get out of the way and permit the clamping ring (86, 286) to be lifted out of engagement with the flange (24). The latch mechanism of claim 1 wherein said handle (82a) extends outwardly from said cam (82b) at a location at an end of said cam. The latch mechanism of claim 1 wherein said handle (282a) extends outwardly from said cam (282b) at a location between ends of said cam. The latch mechanism of any of claims 1 through 3 wherein said clamping ring (286) has a notch (286a) that is engaged by said rounded cam surface of the lever (282) when the lever is in clamping engagement with said clamping ring (286). The latch mechanism of any of claims 1 through 4 wherein said support member (84) is slidably supported on said first axis (D) to take a first position, wherein the support member (84) is fixed against rotation about the first axis (D) and a second position in an enlarged area (88a) in the fixing structure (88) allowing the support member (84) to be pivoted. The latch mechanism of any of claims 1 through 5 wherein said first axis (D) defines a plane perpendicular to such axis (D) and wherein said second axis (C) is contained in said plane offset from said first axis (D). The latch mechanism of claims 5 or 6 wherein said second axis (C) extends horizontally when said support member (84) is in its first position. The latch mechanism of any of claims 1 through 7 wherein said rounded cam surface has a variable radius with respect to said second axis (C). The latch mechanism of any of claims 1 through 8 wherein a plurality of circumferentially spaced apart latch mechanisms (80, 280) are mounted around an opening of a glass melting forehearth installation (20).

Inventors: DIFRANK FRANK J, LEIDY D WAYNE, RUGH WILLIAM B, DIFRANK, FRANK J., LEIDY, D. WAYNE, RUGH, WILLIAM B.
Applicants: OWENS BROCKWAY GLASS CONTAINER, OWENS-BROCKWAY GLASS CONTAINER INC.
Application year: 1999
Main classification: C03B7
IPC codes: F16D1, C03B7, F16B2