Geometry of wood screws: a patent review

Abstract

The article describes the results of the review and analyses of the patent literature relating to screws for wood materials used in the furniture manufacturing and in building construction. Based on the queries performed in several databases, 611 patent families containing 1031 unique patent documents from 1902 to 2017 have been identified. These documents were analyzed, and as a result, an overview was obtained containing screw inventions that are the most influential for the present state of the art of joinery. The number of forward citations and sizes of patent families were considered in the identification of the inventions recognized as the most influential. Additionally, the oldest often-cited screw patents were also quoted. As a result, eight very significant screw inventions were identified and the types of technical issues that these inventions solve were indicated. Additionally, these results were confronted with topics taken in scientific literature. This confrontation points to the weak link between scientific literature and patent literature in the field of threaded fastener for wood materials.

Design issues of innovative furniture fasteners for wood-based boards

“…There is moderate diversity among the fastener anchoring methods; it is possible to use direct fastening (in the form of screwed in, nailed or glued mandrel) or indirect fastening (screwed or nailed in screwed or expanding muff) methods (Table 1). Other anchoring solutions (e.g., glued, directly frictional, shape-frictional (Branowski et al 2018) or expanding -with catches pulled out from the body when the fastener is closed) are used less often for fastening connectors in the furniture, the most common way to anchor the furniture fastener is to use a thread (Sydor 2019). Figure 2 presents some examples of engineering solutions of fastener anchoring systems in furniture.…”

“…They provide connections with a strong local concentration of stress, connected with the transfer of forces from one joined element onto the other. The distribution of stresses is uneven along the length of the thread because of a very small elastic deformation of the threaded metal mandrel and nonuniform elastic deformation of the mounting sockets in the joined furniture panels made of foamed lignocellulosic fibrous composite (Sydor and Wieloch 2009;Sydor 2019;Chen et al 2019). The material of the steel mandrel of the fastener (either extended or compressed) is much more rigid than the material of the lignocellulosic board; the concentration of load is at the end of the mandrel and increases with the increase in the Et/Ek ratio of the Young's modulus of the mandrel and the wood composite board (e.g., the Et/Ek ratio is approximal 75 for chipboard and approximal 20 for oakwood).…”

Wood screw design: influence of thread parameters on the withdrawal capacity

“…For joining elements made of wood, wood-based materials, and for metal-to-timber-connections, one of the preferred methods is using wood screws (Sydor 2019;Ringhofer and Schickhofer 2014). The use of wood screws, especially selftapping ones, has increased in recent years (Frese and Blaß 2009).…”

“…It is used in the design of structural engineering and is therefore an essential optimization parameter for wood screws. According to Sydor (2019), the withdrawal capacity is usually analyzed for changing the constructive properties of wooden workpieces. Although it can be suspected that screw manufacturers have conducted tests on the influence of thread parameters on withdrawal capacity, there are no studies with significant results.…”

The accuracy of holes drilled in the side surface of plywood

“…Holes in wood and wood-based materials are usually made to attach fasteners (e.g. with screws furniture dowels and other connectors (Smardzewski 2015;Sydor 2019;Sydor and Wieloch 2009). In case of industrial furniture production, holes are made with multispindle drill.…”