Normalised Elements of Drawing

Among the numerous types of drawing lines, which constitute the subject of the standard PN-82/N-01616 in industry standards regarding the furniture technical drawing, according to BN-90/7140-03/05, the types of lines presented in Fig. 5.13 are used. In addition to this, there are several line thicknesses selected, depending on the drawing sheet format.

Different types of lines have the following uses:

• A thick continuous line is used to draw:

– the outline of the box “drawing number” in the title block.

• A medium continuous line is used to draw:

– visible edges, outlines and blending lines,

– visible places of contact of parts,

– displaced quads,

– plane trace of the cross section,

– drawing simplifications of joints,

– drawing borders and

– outline of the title block and its main boxes.

• A thin continuous line is used to draw:

– dimensional lines and auxiliary dimensional lines,

– hatching cross sections,

– reference lines along with the “shelves” and marking details,

– local quads,

– axis of circles and other geometric figures with a diameter less than 12 mm,

– columns and rows in boxes of the drawing block,

– markings of the direction of veneer fibres on cross sections and views,

– markings of adhesive bonds,

– lines limiting an enlarged detail,

– drawing simplifications of fittings (on views) and the thread line and

– veneer line on cross sections.

• A thin spline (curved) line is used to draw:

– invisible edges, outlines and blending lines and

– invisible places of contact of parts.

• A thin dot line is used to draw:

– imaginable axis of objects (e. g. axis of symmetry),

– the axis of circles and other figures with a diameter or dimensions above 12 mm and

– arbitrary markings of repeated joints.

• A thin double dot line is used to draw:

– extreme or significantly different positions of moving parts and

– the outline of parts presented when expanded.

• A zigzag continuous line is used to draw:

– interruptions or tears of projections,

– limitations of the projection from the view (tears) and

– partial limitation of the view or cross section.

• A thin continuous polyline for drawing interruptions or tears of projections.

In a furniture technical drawing, for most joints, fittings and accessories, drawing simplifications are applied (BN-90/7140-03/03, Table 5.4) reducing the time of documentation being drawn up. Joints should be drawn in simplified or arbitrary markings depending on the scale of the drawing and the number of repetitions. The arbitrary presentation is recommended to be used particularly in the case of a series of repeated same joints and in drawings made in reduced scales. The dimensions of these joints should correspond to actual basic dimensions, such as the diameter and length of the core, and the dimensions of screw heads. Examples of applying drawing simplifications have been provided in Fig. 5.14.

Table 5.4 Simplified and arbitrary markings of selected joints in a furniture technical drawing (BN-90/7140-03/03)

Fig. 5.14 Examples of markings: a) simplified and b) arbitrary

When describing the joints, presented in simplification using reference lines and inscriptions, information details should be provided about the name, dimensions, number of norm or number corresponding to the position number in the title block. Joints of a perpendicular axis to the plane of the drawing are arbitrarily presented always in the form of two short sections of a thin continuous line crossed over at a right angle. Furniture fittings should be drawn in a simplified manner, without marking construction details, slants, phasings, etc., on them, presenting only their outlines resulting from overall dimensions. Detailed information about the fittings, such as the number or catalogue symbol, drawing number, and for a special fittings also characteristic dimensions, is entered in the title block, by providing the number of the box on the shelf of the reference line. On the reference line, it is also permissible to provide more information about the fittings. This applies to cases in which a list of parts in the title block is not provided. Symmetrical fittings, such as handles, support pegs under shelves, grooves for keys and escutcheon plates, can be presented in the form of an intersection point of two perpendicular axes made in a point line or thin continuous line depending on the characteristic dimensions of the presented fittings.

The position of the fittings drawn in a simplified manner is provided by dimensioning the distance of the fittings from the edge of the furniture element, on which they occur. For fittings presented using a point, the distance of the inter­section point of the axis of symmetry from the edge of the element is provided. Other drawing simplifications concerning, among others, joint parts provided in PN-81/N-01613, riveted and soldered joints in PN-76/N-01635, welded in PN-79/M-01134 and PN-64/M-01138.

Standardised drawing elements also include graphic markings of wood-based materials, upholstery materials and others used commonly in furniture production (BN-90/7140-03/04). The more important of these markings have been provided in Table 5.5.

Table 5.5 Graphic marking of materials (BN-90/7140-03/04)

Graphic marking of cross-section

Wood cross-section

Wood longitudinal cross-section

Carpentry board cross-section

Carpentry board longitudinal cross-section

Chipboard

Honeycomb board

Plywood

HDF

MDF

Metals

Plastics, rubbers

Glass and other transparent materials Polyurethane foam Coconut mat, stubble and latex Lining material, covering Fabrics

Sinusoidal spring Spring unit top view

Spring unit vertical cross-section

In natural and artificial veneers, the outer layer on cross sections made to the scale of 1:2, 1:1 or more should be presented using thin continuous lines, about 20 mm in length, running inside the cross section at a distance of 1 mm from the contour lines (Fig. 5.15).

Veneers should not be presented on cross sections made in other reduced scales. Subveneers are also not presented on the cross sections.

The direction of the fibres of natural veneers or a clearly visible drawing of wood of synthetic veneers should be marked on the outer side in the following manner (Fig. 5.15):

• longitudinal direction in relation to the plane of the cross section using an arrow with a length of about 10 mm;

• transverse direction in relation to the plane of the cross section using a cross with a length of the arms of about 4 mm.

The direction of the fibres of a natural veneer or drawing of wood of a synthetic veneer on views should be presented using a system of three lines (Fig. 5.15). The middle line should be approximately 2 times longer than the outer lines. The direction of the fibres in solid wood or the outer veneers of plywood is marked the same as the direction of fibres in the veneers.

By drawing cross sections of materials, they should be hatched by thin con­tinuous lines. Diagonal hatching is carried out at an angle of 45° to the line of the border of the drawing with a slope to the right or left. If two transverse cross

Table 5.6 The symbols of markings used in clothing technical drawings (Czurkowa and Ulawska-Bryszewska 1998)

Drawing

symbol

Description

Application

J

Piercing with needle

In sewing marking

f

Sewing direction

In markings of symbol of stitches and seams

a

Zigzag stitch

In marking of sewing direction

i

Surge stitch with one thread

In markings of edges finishing, decorating etc.

Surge stitch with two threads

In markings of edges finishing, decorating etc.

Blind hem stitch

In marking of sewing direction

o=>

Overlockstitch

In markings of hem finishing

Protrusion

In marking of protrusions

Outside surface of material

In markings of the outside surface

о—о

Inside of material

In markings of the inside surface

j

Material thickness

In markings of material thickness

sections lie next to each other, then the second cross section should be hatched with a slope rotated by 90°, and in the case of three cross sections, the smallest of them is hatched more densely.

In drawings realised at a large reduction, or when there is no room for hatching in the drawing, blackening the cross sections is permitted. If the blackened areas on the cross section are in contact with each other, then they should be drawn with a small space in between.

In furniture technical drawing, next to previously provided standardised ele­ments, also other rules of machine drawing apply, in particular:

• rectangular views and locating views according to PN-78/N-01608,

• axometric views according to PN-82/N-01619,

• views and cross sections according to PN-79/M-01124,

• writing according to PN-80/N-1606,

• dimensioning according to PN-70/M-01143, PN-70/M-01141 and

• tolerating dimensions and shape according to BN-81/7140-11.

When preparing technical documentation of upholstered furniture, drawings of templates and systems of the fabric and leather cuts should also be done. These are so-called tutorial drawings of technological processing indicating how to make a given piece of cover for an upholstered furniture piece. Drawing symbols of stitches and seams are included in the Polish Standards. Table 5.6 shows the selected symbols of markings used in drawing up tutorial drawings.

Regular joining Two layers of material sewn seam

Lapped ioinmg

Two layers oi material sewn

seam

Materials sewn in one plane

3 Overlapping

joining seam

Fig. 5.16 Examples of machine stitches and seams: a, b regular stitch, c zigzag stitch, d surge stitch, e surge stitch and f blind hem stitch

• The set includes a bookcase, a desk, a container and side table;

• The cupboard for documents has a height of 1800 mm, a width of 800 mm and a depth of 420 mm. The distance between movable shelves provides free storage of office binders, documents in formats A4, B5, etc.;

• the cupboard is designed for use in offices, libraries, post offices, banks and other similar public institutions. The furniture piece is fitted with two drawers with hooks for files. Full extension of drawers enables free access to stored collections; and

• the body of the furniture is made of chipboard covered with laminate, veneered at the edge with PVC, the doors with a tempered glass filling—made of beech wood, frontal elements finished with side-laminated board covered with a transparent water-dilutable lacquer with a glossiness of 15°.