SU1276615A1 - Tackle block - Google Patents

Abstract

The invention relates to hoisting-and-transport mechanisms, in particular, to a polyspast. The aim of the invention is to expand the change in the range of the multiplicity of the hoist (P). П contains movable blocks (ПБ) 1, 4, 5 and placed symmetrically about the axis of symmetry (о.с.) П fixed blocks (НБ) 2 and 3. ПБ 1 is placed on о.с. П, and ПБ 4, 5 are fixed on the traverse 6 and are located at the same distance from the bay. P. A flexible cable body 7 connecting the PB and the NB is made infinite, and its branches form an angle with a.s. P, varying B, depending on the stroke size of the PB 1. Two loops of the traction organ bend around the top and bottom of the PB 1. The work of P comes from making an effort to move the PB 1. 1 Il. & (L with SP

Description

t

The invention relates to lifting and transport mechanisms, in particular to the structures of the chain hoists.

The purpose of the invention is the expansion of the range of change of the multiplicity of the polyspast.

The drawing shows the proposed polyspast, General view.

The polyspast consists of fixed 1 and 2 and movable 3, 4 and 5 blocks, as well as an infinite flexible body 6 Mobile block 3 is located on the axis of symmetry of the chain hoist, movable blocks 4 and 5 are installed on traverse 7 and are located at the same distance - the SRI, and fixed blocks 1 and 2 are at the same distance from the axis of symmetry of the chain hoist. The flexible body 6 is made infinite and is carried out successively through blocks 1,3, 2, 5, 3, 4, returning to the initial block 1. The branches of the flexible body 6 going upwards from the movable block 3 are inclined to the axis of symmetry of the polyspast at an angle (I varies depending on the stroke h of block 3, and the branches connecting blocks 1 and 2 with blocks 4 and 5 are inclined to the axis of symmetry of the chain hoist at an angle (3, varying depending on the stroke length L of the traverse 7). The traction unit of the chain pulley is the movable unit 3. The frequency of the chain pulley is variable, and depending on the magnitude of the angles oi and (3.

We give a mathematical description

work polyspast. The magnitude of the t of govoy Q force on a movable yoke 7

Q 2-p / 1 cos with

Cos

R

the force applied to the mobile unit 3 and directed upwards along the axis of the chain hoist, according to the drawing

arctgC--) p a; rctg (.- jj--),

where d is the diameter of block 3, and therefore Q iP,

Where

one -

1 - 21 cosft

766152

Exodus from the principle of conservation - energy

V, P VO,

5 Hz-e V is the speed of movement of the yoke 7, V is the speed of movement of the rolling block 3.

In accordance with the preceding and expressions we find V, whence

O it follows that the stroke size L „is directly proportional to h, with the proportionality coefficient equal to 1 / i.

Thus, the i value, which determines the gain in Q and the loss

5 in speed V, is the multiplicity of the polyspast, depending on the stroke h.

Polyspast works as follows. Block 3 is applied to unit R. Block 3, moving at a speed Ud, weakens the branches of a flexible organ 6 thrown over blocks 1 and 2, which make a rotational movement in different directions: block

5 1 against, and block 2 clockwise. The branches of the flexible organ 6 passes further through blocks 4 and 5, closing on movable block 3. This causes rotation of blocks 4 and 5, established

30 on the moving yoke 7. The latter moves with the speed V and develops the force Q. The block 3 can oscillate from the equilibrium position axis, thereby equalizing the load between

Claims (1)

5 right and left parts of the polyspast. Invention Formula A polyspast containing three movable blocks and two stationary blocks placed symmetrically along the axis of the lispast are connected by a flexible body, whose branches form an angle with the axis of symmetry of the polyspast, which varies depending on the stroke of one of the underglobes, OSU: the rotation of which is located on the said axis of symmetry, characterized in that. in order to expand the range of measurement of the multiplicity of a polyspast, it supplied; with a traverse,  on which two other mobile blocks are installed, located at the same distance from the axis of symmetry of the chain hoist, and the above t - beef organ is made infinite with 5 with two loops enveloping the top and bottom of the movable block with the axis of rotation located on the axis of symmetry of the chain hoist.