There are many ways in which structures such as shelving, scaffolding, furniture, clipboards and cabinets are fitted together. Such arrangements include fasteners such as nuts and bolts, wooden dowels, nails and other types of intricate locking mechanisms. Dowels are the most common connectors of furniture. The dowel is typically symmetrical about its axial midpoint and is typically provided with one or more longitudinally extending grooves or some other type of profiling on the outside of the dowel. The dowel is typically inserted into a cylindrical bore drilled into the furniture part in which the dowel is to be connected therein. Adhesives are commonly placed into the central bore prior to insertion of the dowel so that an improved connection between the bore and dowel is made.
The preparation and construction of furniture requires special knowledge and special skills. Many types of furniture are not preassembled and are commonly transported to the location where they are to be assembled. During such transportation, many of the connection components are exposed to adverse types of environments such as low and high humidity which results in the cracking and/or expanding of the dowels. Such expanding and cracking of the dowels results in the weakening of the structure in which the dowel is connecting and/or resulting in the dowel not being able to be properly placed within the pre-drilled bore hole. In addition, special skill is required when inserting a dowel into a bore hole containing a liquid adhesive. In order to achieve an interference fit between the bore and the dowel, the diameter of the dowel is typically slightly greater than the diameter of the bore hole thereby requiring the dowel to be driven or pressed into the bore hole commonly resulting in much of the adhesive being forced out of the bore hole. In order to overcome the problems with using dowels and adhesives, many manufacturers have used screws or nails to attach components such as furniture together or to secure a dowel in position. Although the use of a screw or a nail typically provides an adequate connection, the aesthetic value of the component, such as fine furniture, is severely prejudiced due to the appearance of the visible nail or screw.
As is apparent, the use of a dowel in combination with an adhesive is time consuming and requires great care. Furthermore, soiling of the surfaces and parts commonly occurs with the use of liquid adhesives. Also, the amount of adhesive placed in the bore is important so as not to cause significant waste and cleaning problems when the dowel is inserted into the bore. The prior art includes several solutions to remedying the problem associated with dowels and liquid adhesives.
In U.S. Pat. No. 4,681,477, an enclosed capsule filled with a specific amount of adhesive is placed into the cylindrical bore prior to inserting the dowel into the bore. The pre-measured amount of adhesive is designed to reduce the problems caused when the dowel is inserted into the bore, the adhesive flows out of the bore causing a mess. Furthermore, sealing the adhesive reduces problems associated with spillage of the adhesive onto the furniture. However, the use of a glue capsule does not insure that the glue uniformally coats the inserted dowel to insure that the dowel uniformally adheres to the bore. Furthermore, the use of a glue capsule still requires the assembler to carefully insert the dowel into the bore so that the dowel is properly aligned in the bore to rupture the glue capsule. In addition, the assembler does not have any indication when the dowel has been completely inserted into the bore. Finally, the use of the glue capsule does not allow the assembler to remove the dowel after complete insertion into the bore if any problems result in the initial insertion of the dowel since such removal would cause a mess and the glue in the bore and on the dowel would dry, thereby preventing reinsertion of the dowel into the bore.
In U.S. Pat. No. 5,259,686, a dowel is coated with a water soluble glue prior to inserting the dowel into the bore. Once the dowel is inserted into the bore, liquid is injected about the dowel and into the bore thereby activating the glue and creating a connection between the dowel and the cylindrical bore. The coating of the dowel with the water soluble glue assists in uniformly gluing the dowel to the cylindrical bore. The water soluble glue also reduces the problems associated with excess glue flowing out of the bore as the dowel is inserted. However, the use of such a dowel does not indicate to the assembler as to whether the dowel has been properly and completely inserted into the cylindrical bore. Such improper alignment of the dowel would require the assembler to drill out the rigidly connected dowel or have connected pieces improperly aligned. The dowel design also does not allow for intermediate assembly to ensure proper setup prior to final assembly. These problems become more severe when fine furniture is assembled which has very small tolerances and requires a precision connection. The dowel is also a typical interference fitting dowel. The tight fit of the dowel in the bore requires any water applied to the dowel and bore to slowly wick into the bore to re-wet the glue. However, improper re-wetting can occur if not enough water is applied and/or if the dowel is too tightly fitted in the bore thereby interfering with the wicking effect.
As a result, there has been a demand for a connector which forms a clean and secure connection, allows an assembler to assemble and disassemble parts as needed to fully assemble the components and to form a rigid and strong connection when the components are in their final assembled form.