Method of forming adhesive joint, structural subassembly, and joint construction

Abstract

A method of forming an adhesive joint, a structural subassembly, and a joint construction. The method comprises telescopically assembling male and female tubular members having slightly different diameters to cooperatively define a narrow continuous open-end adhesive chamber between contiguous surfaces of the assembled members. Four (4) or more centering pins equally circumaxially spaced about the members are forcefully entered in the adhesive chambers to equalize spacing between the members throughout the chamber. A distributing device communicates with the adhesive chamber for the introduction of adhesive under pressure to the chamber, thus forming a secure joint. In a fabrication method for a structural subassembly at least three (3) tubular structural members are loosely assembled with three (3) joint members each having at least two cups. Centering pins are forcefully introduced between contiguous surfaces of the members and cups and a distribution device encloses the open end of the adhesive chamber. Adhesive is then introduced between the contiguous surfaces of the members to form secure joints throughout. A joint construction is produced in the practice of the method of the invention.

1 . For use in constructing a wind turbine tower; a method of forming an adhesive joint comprising the steps of telescopically assembling male and female members having cross sectional configurations which are similar but slightly different in size so as to cooperatively define an open end adhesive chamber between contiguous surfaces of the members, providing centering means which engage the contiguous surfaces of the assembled members and substantially equalize spacing between the members throughout the adhesive chamber, providing an inlet port communicating with the adhesive chamber, injecting an adhesive through the inlet port to fill the adhesive chamber substantially uniformly throughout the area between the members to be joined, and curing the adhesive to form a secure joint. 
     
     
         2 . A method of forming a joint as set forth in  claim 1  wherein the centering means takes the form of at least one locating pin positioned in the adhesive chamber and engaging the opposing contiguous surfaces of the adjacent male and female members. 
     
     
         3 . A method of forming a joint as set forth in  claim 2  wherein at least one locating pin is positioned in the female member prior to the telescopic assembly of the male and female members. 
     
     
         4 . A method of forming a joint as set forth in  claim 2  wherein the at least one centering and fixing pin is forcefully inserted into the adhesive chamber and into engagement with the contiguous surfaces of the male and female members subsequent to the telescopic assembly of the members whereby to both center the male member and firmly fix the male and female members relative to each other. 
     
     
         5 . A method of forming a joint as set forth in  claim 1  wherein the centering means comprises at least one elongated integral longitudinally extending rib on one of the male and female members, which engages and centers the male member during telescopic assembly of the members. 
     
     
         6 . A method of forming a joint as set forth in  claim 1  wherein at least one short centering means is provided on the surface of one of the male and female members spaced substantially inwardly from the mouth of the female member to engage and center the male member toward the end of the telescopic assembly of the members. 
     
     
         7 . A method of forming a joint as set forth in  claim 1  wherein the female member is provided with a shoulder spaced from its open end and engageable with the free end of the male member to act as a stop when the latter in inserted into the female member. 
     
     
         8 . A method as set forth in  claim 1  wherein the female member is effectively closed beyond the end of the assembled male member so as to prevent loss of adhesive and yet allow air to escape and thereby prevent voids in the adhesive. 
     
     
         9 . A method as set forth in  claim 7  wherein an annular sealing insert is provided and is disposed between the shoulder and the inner end of the male member and allows air to pass but serves as a barrier to adhesive to prevent voids in the latter. 
     
     
         10 . A method as set forth in  claim 1  wherein an annular sealing insert is provided and is disposed between the axially extending surfaces of the male and female members adjacent the inner end of the male member and allows air to pass and serves as a barrier to adhesive to prevent voids in the latter. 
     
     
         11 . A method as set forth in  claim 10  wherein an annular end cap is provided for the inner end of the male member and mounts the annular seal with its inner surface spaced radially inwardly from the end of the radial end surface of the male member, the seal then being inserted into the mouth of the female member without distortion which might compromise sealing efficiency. 
     
     
         12 . A method as set forth in  claim 11  wherein the end cap is provided with an annular chamfer to direct the same into the mouth of the female member. 
     
     
         13 . A method as set forth in  claim 11  wherein the end cap is of a clear transparent plastic and serves as a visible indicator of uniform adhesive distribution about the radial end portion of the male member. 
     
     
         14 . A method as set forth in  claim 11  wherein the small indicator openings are provided in the end cap for determining complete filling of the inner end portion of the adhesive chamber. 
     
     
         15 . A method as set forth in  claim 11  wherein a deep annular notch is provided in the annular end cap and wherein a ring seal is provided in the notch with an outwardly projecting substantially convex surface in cross-section. 
     
     
         16 . A method as set forth in  claim 15  wherein the end cap is provided with an inclined annular lip seal extending outwardly between radial and axial planes adjacent and toward the convex surface of the ring seal. 
     
     
         17 . A method as set forth in  claim 1  wherein a flexible inclined annular lip seal is provided on the end cap and engages and is flexed radially inwardly during assembly of the male and female members, whereby to reside in sealing compression in the assembled state of the members. 
     
     
         18 . A method as set forth in  claim 1  wherein the male member is solid. 
     
     
         19 . A method as forth in  claim 1  wherein both the male and female members are tubular. 
     
     
         20 . A method as set forth in  claim 19  wherein both the male and female members are thin-walled cylindrical tubular members, 
     
     
         21 . A method as set forth in  claim 4  wherein at least three locating pins are provided in substantially equally spaced relationship around the members. 
     
     
         22 . A method as set forth in  claim 21  wherein at least three (3) equally-circumaxially spaced entry notches are provided around the mouth of the female member each with a gradual chamfer for directing a locating pin into the adhesive chamber and into engagement with the male and female members. 
     
     
         23 . A method as set forth in  claim 20  wherein the members are thin-walled cylindrical tubular members of galvanized structural steel. 
     
     
         24 . A method as set forth in  claim 1  wherein an adhesive distributing device is positioned about the free end of the female member and has an inlet port communicating with the adhesive chamber. 
     
     
         25 . A method as set forth in  claim 1  wherein an adhesive inlet port is provided in the female member intermediate its ends and wherein seals are provided at opposite ends of the adhesive chamber. 
     
     
         26 . A method as set forth in  claim 1  wherein an annular seal is provided adjacent the inner end of the male member that allows air to pass but serves as a barrier to adhesive, and wherein adhesive is introduced to the adhesive chamber at substantially constant volumetric flow rate with injection being terminated when a pressure rise indicates adhesive covering the face of the seal and a completely full adhesive chamber. 
     
     
         27 . A method for fabricating a structural assembly for use in a wind turbine tower comprising the steps of providing at least three elongated tubular structural members arranged in spaced relationship with at least three associated joint members each having at least one short connecting member differing in diameter from the tubular structural members, the structural members and short connecting members thus being adapted for male-female telescopic assembly each having an annular open end adhesive chamber therebetween, positioning the structural assembly with the members and short connecting members in loose male-female telescopic relationship, providing centering means in each adhesive chamber to locate the structural members and short connecting members in substantially uniformly spaced relationship with resulting adhesive chambers of substantially uniform width therebetween, providing an inlet port communicating with each adhesive chamber injecting an adhesive into said inlet port whereby to fill said adhesive chamber uniformly throughout the area between the members to be joined, proceeding to second, third and all remaining joints, and repeating the adhesive injection procedure and curing the adhesive in all adhesive chambers to form secure joints throughout. 
     
     
         28 . A method for fabricating a structural assembly as set forth in  claim 27  wherein said centering means comprises at least one locating pin forcefully inserted into each adhesive chamber to engage contiguous surfaces of the male and female members. 
     
     
         29 . A method for fabricating a structural assembly as set forth in  claim 28  wherein at least one short centering means is provided on at least one of said male and female members spaced substantially from the mouth of the female member to engage and center the male member toward the end of the telescopic assembly of the members. 
     
     
         30 . A method for fabricating a structural assembly as set forth in  claim 27  wherein each female member has a shoulder spaced from its open end engageable with the end of the male member and acting as a stop when the latter is inserted into the female member. 
     
     
         31 . A method as set forth in  claim 27  wherein each female member is effectively closed beyond the end of the assembled male member. 
     
     
         32 . A method as set forth in  claim 30  wherein an insert is positioned between the shoulder and the inner end of each male member and allows air to pass but serves as a barrier to adhesive loss. 
     
     
         33 . A method as set forth in  claim 31  wherein an additional seal is provided adjacent the free end of the female member. 
     
     
         34 . A method as set forth in  claim 27  wherein both the male and female members are thin-walled tubular members constructed of galvanized structural steel. 
     
     
         35 . A method as set forth in  claim 31  wherein at least three (3) locating pins are provided and are equally spaced around the cylindrical tubular members. 
     
     
         36 . A method as set forth in  claim 27  wherein said structural members are arranged in angularly displaced closed loop relationship with each other. 
     
     
         37 . A method as set forth in  claim 27  wherein a fixture is provided and wherein said structural members and short connecting means are initially positioned in loose interconnection and in subassembly relationship with the aid of the fixture. 
     
     
         38 . A method as set forth in  claim 27  wherein an annular end cap is provided for the inner end of the male member and adhesively mounts an annular seal with its inner surface spaced radially inwardly from the axial surface of the male member, the seal then being inserted into the mouth of the female member without rolling up and other distortion. 
     
     
         39 . An adhesive joint as set forth in  claim 38  wherein an adhesive distributing device is positioned about the free end of the female member and has an inlet port communicating with the adhesive chamber. 
     
     
         40 . For use in a wind turbine tower; an adhesive joint between telescopically related male and female members having cross sectional configurations which are similar but slightly different in size so as to cooperatively define a narrow open end adhesive chamber between contiguous surfaces of the assembled members, at least one centering means positioned in the adhesive chamber and engaging the contiguous surfaces of the two members and substantially equalizing the space between the members throughout the chamber, said adhesive chamber being filled with adhesive uniformly throughout the area between the members to be joined. 
     
     
         41 . An adhesive joint as set forth in  claim 40  wherein an adhesive distributing device is positioned about the free end of the female member and adhesive is introduced through an inlet port communicating with the adhesive chamber. 
     
     
         42 . An adhesive joint as set forth in  claim 40  wherein the centering means takes the form of at least one locating pin in the adhesive chamber engaging the contiguous surfaces of the male and female members in a press fit. 
     
     
         43 . An adhesive joint as set forth in  claim 40  wherein at least one integral rib comprises the centering means and projects from the surface of one of the male and female members to engage the contiguous surface of the male member. 
     
     
         44 . An adhesive joint as set forth in  claim 40  wherein a centering means includes at least one short rib on the interior surface of one of said male and female members spaced substantially from the mouth of the member to engage and center the male member toward the end of a telescopic assembly of the members. 
     
     
         45 . An adhesive joint as set forth in  claim 40  wherein one of the male and female members has a shoulder spaced from its end engageable with the end of the opposite member and acting as a stop when the male member is in inserted into the female member. 
     
     
         46 . An adhesive joint as set forth in  claim 42  wherein an annular sealing insert is disposed between the shoulder and the inner end of the male member and allows air to pass but prevents adhesive loss. 
     
     
         47 . An adhesive joint as set forth in  claim 40  wherein an annular sealing insert is disposed about the male member and in engagement with the axially extending surface of the female member adjacent the end of the male member and allows air to pass but prevents adhesive loss. 
     
     
         48 . An adhesive joint as set forth in  claim 40  wherein both male and female are thin thin-walled tubular members of galvanized structural steel. 
     
     
         49 . A method as set forth in  claim 40  wherein an annular end cap is provided for the inner end of the male member and adhesively mounts an annular seal with its inner surface spaced radially inwardly from the end of the radial end surface of the male member, the seal thus being inserted into the mouth of the female member without rolling up and other distortion. 
     
     
         50 . A method as set forth in  claim 49  wherein a deep annular notch is provided in the annular end cap and wherein a ring seal is disposed in the notch with an outwardly projecting substantially convex surface. 
     
     
         51 . A method as set forth in  claim 49  wherein the end cap is provided with an inclined annular lip seal adjacent the convex surface of the ring seal. 
     
     
         52 . A method as set forth in  claim 40  wherein a flexible inclined annular lip seal is provided on an end cap for the male member and engages and is flexed radially inwardly during assembly of the male and female members whereby to reside in sealing compression in the assembled state of the members.