SU370080A1 - DEVICE FOR BUILDING ELASTIC CURVES - Google Patents

Description

one

The invention relates to the field of mathematical instruments and can be applied in the graphoanalytical solution of the problems of plane bending of thin rods for any magnitude of elastic deformations.

A device for constructing elastic curves is known.

The purpose of the invention is to mechanize the process of building elastic curves. This is achieved by the fact that the device contains a graduated guide, three carriages, one of which is mounted on a guide and carries a graduated ruler perpendicular to it, the second is installed on this ruler and carries a food-making device, and has a reading roller for measuring the length of the curve and two support knife rollers, one of which is rotatable (steering), and means for turning the steering roller relative to the third carriage, moreover, as means tangensny applied steering roller mechanism trosoblochnoy transmission.

FIG. 1 shows the proposed device, top view; in fig. 2 - third carriage; in fig. 3 is a block transfer scheme.

On the guide I, which is installed parallel to the abscissa axis of the graph, a carriage 3 with a graduated ruler 4 mounted parallel to the axis of ordinates is mounted with the help of the slide 2. On the ruler there is a carriage 5, in the joint 6 of which, having a degree scale 7, is located a turning carriage 8 with cutter rollers (support) 9 and 10 and a reading roller 11. Roller 9 is steering. It is mounted in a plug 12, freely rotating in the hinge 13 of the carriage. The plane of the rollers 10 and 11 are fixed relative to the carriage 8; the plane of the knife roller 10 is parallel to the plane passing through the axes of joints 6 and 13; its axis of rotation lies on a straight line perpendicular to this plane and crossing the axis of the joint 6. The plane of the reference roller 11 coincides with the plane passing through the axes of joints 6 and 13.

The cable-block mechanism with a gear ratio equal to one contains shkivy

14 and 15 are of the same diameter, with the pawl 14 fixedly mounted on the fork 12, and the pulley 15 can rotate freely on an axis fixed to the carriage 5, four guide blocks, of which two blocks 16 rotate on axes fixed to the carriage 5, and two blocks 17 — on the carriage 8, and a practically inextensible flexible cable 18. On the graduated pole 19, mounted on the ruler 4 parallel to the guide 1, is fixed

adjustable slider 20, which is hinged

a rod 21 is connected, which slides freely into the groove of the pulley 15. These parts form a tangent mechanism. On the carriage 5 reinforced writing device 22.

The cable-block mechanism, in combination with the tangent, rotates the plane of the steering roller 9 relative to the plane passing through the axes of the hinges 6 and 13, depending on the position of the carriage 5 relative to the axis 6. The cable-and-block transmission is assembled so that the plane of the steering roller 9 coincides with the plane passing through the axes of the hinges 6 and 13, if the rod 21 is parallel to the guide 1. In this case, the writing device is on the compression line (abscissa axis).

When the carriage 8 is moved along the paper, the axis of the hinge 6 and, therefore, the tip of writing device 22 describes a curve with an instantaneous curvature value

: - tgT,

where d is the distance between the axes of the hinges 6

and 13 (instrument constant); F is the angle of rotation of the plane of the steering roller 9 to the plane passing through the axes of the hinges 6 and 13, determined by the formula

(f aTcig-, s

where y is the ordinate of a curve point;

с - changeable shoulder of the tangent mechanism.

Consequently, the instantaneous value of the curvature reproduced by the curve satisfies the equation - --- y, i.e. the curve is p cd

Elastic.

Drawing elastics are as follows. Moving the carriage 5 along the ordinate axis, the writing device is shifted from the abscissa axis to the specified distance yo. The carriage 8 is rotated at a predetermined angle vo of inclination of the elastic curve to the compression line at a given starting point along the degree scale 7. By shifting the slider 20 along the rod 19, the shoulder of the tangent mechanism is installed with ML

d

for a given initial curvature -. 5ro

When moving the carriage 3 along the abscissa axis, the writing point draws the elastic with the given initial parameters.

When building elastic for rods with 10-V „1

the initial initial curvature is, i.e., satisfying an equation of the type

W, / PEF

the abscissa axis of the graph is shifted by an amount, since the equation of such a curve

(Y ± a).

can be represented as -

  p Ef

R

Linear scale on the rod 19 can be replaced by a circular scale of curvature, mounted on a adjustable slider 20.

Subject invention

Claims (2)

1. A device for constructing elastic curves, characterized in that, for the purpose of mechanization of the process, it contains a graduated guide, three carriages, one of which mounted on a guide and bears a graduated ruler perpendicular to it, the second is mounted on this ruler and carries a writing device, and a third is fixed to the second one with the possibility rotation and has a reading roller for measuring the length of the curve and two support knife rollers, one of which is swiveling (steering), and means for turning the steering roller relative to the third carriage. 2. The device according to claim 1, characterized in that, in order to ensure a proportional relationship between the curvature and the ordinate curve, a tangent mechanism with a cable-and-block transmission is used as a means of turning the steering roller. ff 7 B 8 fuz / eleven w 7 YU G7 9ig 2