pattern

pattern

Manufacturing a wooden or metal shape or model used in a foundry to make a mould

Pattern

The juxtaposition of repetitive elements in a design, organized so as to produce an arrangement of parts that are viewed as an unit; may occur at various scales and sizes.

Pattern

 

(also, development), in geometry. The pattern of a polyhedron is a set of polygons for which it is shown how the sides and vertices of the polygons must be joined in order to ob-

Figure 1

tain the polyhedron. Several conditions must be met here: each side of a polygon must be joined to no more than one side of another polygon; it must be possible to pass from one polygon to another polygon by traversing pairwise joined polygons; and joined sides must have equal lengths. The pattern of a cube is shown in Figure 1.

Figure 2

In such fields as descriptive geometry and drafting, the concept of pattern is sometimes applied to curved surfaces. Thus, the pattern of the lateral surface of a cone is a sector of a circle (Figure 2).

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Pattern

 

(Russian, shablom), in foundry production, an element of a gated pattern, consisting of a flat device whose working side has a highly accurate profile. A distinction is made between molding and control patterns. The former, in the form of wooden boards, are used in individual and small-series production; they take the place of a solid casting pattern or corebox in the manufacture of casting molds and mold cores for medium-size and large castings having the outline of a body of revolution (such as cups, vats, covers, and pulleys). The cavity of the mold or the working surface of the core is produced by rotating the molding pattern around its central axis (a core spindle is positioned at this place in the mold). Control patterns are made of plywood or sheet steel and are used for checking the accurate placement of cores in the cavity of a casting mold during assembly and preparation for pouring.

M. N. SOSNENKO

pattern

[′pad·ərn]

(aerospace engineering)

The flight path flown by an aircraft, or prescribed to be flown, as in making an approach to a landing.

(engineering)

A form designed and used as a model for making things.

(graphic arts)

A design or form.

(mathematics)

An equivalence class of colorings of the elements of a finite set, which are indistinguishable with respect to a group of permutations of the colors.

(ordnance)

The distribution of a series of shots fired from one gun or a battery of guns under conditions as nearly identical as possible, the points of impact of the projectiles being dispersed about a point called the center of impact.

pattern

1. A model made in some easily worked material (such as plaster or wood) which serves as a guide, with respect to form and dimensions, in laying out any piece of work, esp. to preserve and secure uniformity and accuracy.

2. A design, considered as a unit, of which an idea can be given by a fragment, as a diaper pattern.

3. In molding, a form used to provide the interior shape of the mold.

pattern

Typical radiation pattern of a radar.

i. A flight pattern that an aircraft must follow when approaching for landing and when leaving the airport after takeoff.
ii. Radiation of the transmitting aerial as plotted on a diagram of the field strength for each bearing.
iii. A shape traced out on the ground by the track of the aircraft while following certain procedures, such as making the circuit, making procedure turns, while holding, and while carrying out demonstrations. See circuit and holding pattern.