SU1249212A1 - Screw head with closed slot - Google Patents

Description

 one

The invention relates to mechanical engineering, in particular to devices

and parts for fastening and connecting

elements and parts of machines.

The purpose of the invention is to increase the

the reliability of the screw head.

FIG. 1 shows the screw head, the cut | in fig. 2 is the same longitudinal section along the small axis; spike-j in FIG. 3 - the same, top view.

The head 1 of the screw is provided with a slot 2, bounded by the surface of a half-length lpsoid, the ratio of the major semiaxis of an ellipse formed by intersecting the surfaces of the half-ellipsoid and the end of the head to the minor semiaxis B is 1.9-2.1 with a semi-ellipsoid equal to 1.2-1.3 and the ratio of the largest diameter D of the screw head to the major axis of the ellipse is 1.2-1.3.

d

When performing -r-2.1, the strength of the screw head is reduced, in addition, it is impossible to make the shelling on a cold-heading machine.

five

ten

15

20

25

At - 1.9, the shape of the slot approaches the circle, the cut-off area decreases, transmitting the required torque, and the shear stresses increase, which causes the destruction of the slot. When - f: 1, 2 decreases

strength of the lint head on the border of the transition head in the cylindrical

but

part of the screw, and when - 1.3 occurs

the loss of the ability of the slot to wedge the tool in the slot and push it out when the torque necessary to close is reached, as a result, the strength of the pincer as well as the screw head is reduced.

When - 1 2 decreases the mechanical

3

the strength of the screw head, since the contours of the slot extend beyond the surface forming the screw head, in the case

 1.3 decreases the durability of the slot,

as the area that transmits the necessary twisting force is reduced, the result is destruction

spline.

S

FIG. g

Editor O. Golovach

Compiled by S. Nikulin

Tehred I.Popovich Proofreader E.Sirohman

4214/34

Circulation 777 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Design, 4,

fig.Z

Claims (1)

A CLOSED SCREW HEAD for a screwdriver, characterized in that, in order to increase its reliability, the slot is limited by the surface of the semi-ellipsoid, the ratio of the semi-major axis of the ellipse formed by the intersection of the surfaces of the semi-ellipsoid and the end of the head to the minor axis is 1, -9-2.1, the ratio of the semi-major axis of the ellipse to the maximum depth of the semi-ellipsoid. equal to 1.2-1.3 and the ratio of the largest diameter of the screw head to the major axis of the ellipse is 1.2-1.3. figure 1 C © yo y