Using the characteristics of crane hook group and pulley block
The combination group is on the crane hook hook pulley sliding wheel. A long segment type and two types of hook group
By the can around the central axis move the grooved disc and across the disc of the soft cable (rope, tape, wire ropes, chains, etc.) can be around the center axis move simple mechanical parts processing.
Single hook has the advantages of simple manufacture, convenient use, but by the environment is not good, mostly used in weight for 80 tons of the following processing machinery parts and components in the workplace; weight is often used by the symmetry of the hook.
Formula of saving labor of pulley block
Formula: s=hn. Its height is larger, so that the effective lifting height decreases. In China, about to complete the record on the pulley to Zhou Wang to 14 years Kimi (388 B.C.) modi (also known as the Mozi) and his students to write the book "Mojing".
Pulley block: by the fixed pulley and the movable pulley of the pulley group, both labor and can change the force of the object.
Pulley group with a length of rope hanging objects, filed a fraction of the object is the total weight. The free end of the rope around the movable pulley to calculate a, while bypassing the fixed pulley will not forget.
The use of pulley block is the province of the force, but the cost of distance, the distance moving power is greater than the distance of the moving object.
Use of pulley block:
The fixed pulley and the movable pulley can be combined into a pulley block in order to save and change the scale of the change of the force.
Pulley group principle
The characteristics and the effect of the fixed pulley, the movable pulley and the pulley block
The fixed pulley can change the object of the force, but can not save the object. The pulley pulley with more effort. The combination group is on the crane hook hook pulley sliding wheel. Hot rolling pulley fixed center shaft is fixed is the deformation of hot rolling pulley, lever arm, not effort but can change the direction of a force. Such as: n=5, you need two movable pulleys (3+2). Block both effort and can change the direction of a force. Influence the direction of change, even length of rope can reduce a hot-rolled pulley; to change the influence of the targets, and by adding a set of hot rolling pulley.
In conclusion, pulley design principles can be summarized as follows: the even odd move; with the inevitable move, even less inevitable, to add the inevitable.
Segment type hook group in the past by long hook, the hook group pulley mounted directly on the crane hook crossbeam, reduce the height size, but can only be used for double rate of pulley block.
Hook group classification is extremely wide, usually including: shackle, rings, rings, pear shaped ring, long rings, rings, s hook, hook nose, American hook claw hook, eye shape slide hook, with insurance card eyebolts, chain shackle, with weird, innovative, high quality, Ann feature combination in factories, mines, petroleum, chemical industry, ship, dock and other. Movable pulley is bear two ropes, namely each rope assume objects and dynamic force of pulley is the object and a fraction of the total weight of the pulley. The utilization of the winding rope and how much effort, depends on the use of office block.
The pulley and hook group
The pulley is composed of a plurality of fixed pulley and the movable pulley, and can achieve both effort and change direction to influence. A long segment type and two types of hook group. N is even, the rope from the hot rolling pulley for starting, then all animals are only two hot rolling pulley rope bear.
The characteristics of the pulley block
Using pulley do try, it is easy to see that the use of force, although the pulley group, but costs a distance greater than the distance of power moving distance increased. Hot rolling pulley center shaft with heavy objects moving with the hot rolling pulley is called dynamic, arm lever, can save half of the force, but does not change the direction of a force.
Secondly, determine the fixed pulley number, according to the requirements of the general principle is: two strands of rope with a movable pulley, a pulley with a general dynamic hot rolling hot rolling pulley set. Anti loose nut device should be reliable, thrust shaft takes dust device. In practice often put a certain amount of the movable pulley and the fixed pulley block combined into various forms.
Differential pulley commonly used in workshop (commonly known as chainhoists) is a kind of pulley.
N: string section bearing number. Therefore, the short hook group is only applicable to small crane.
Hook group is a kind of the most common sling hoisting machinery parts processing in. The pulley is lever deformation, belongs to the class of simple mechanical parts processing lever. In order to make the hook can rotate around the axis of torsion, the shaft end of the long type crane hook crossbeam to match the baffle shaft made of an annular groove, allow the beam to move; on the contrary, above pulley shaft the shaft end is flat gap, not to be Xu pulley shaft to move. Hookoften impact in the operation process, should be used in the manufacture of high quality carbon steel has good toughness.
According to the shape of hook group divided into singleanddouble hookhook; according to the manufacturing mode is divided into forging hook group and laminated hook group.
The pulley is of two kinds: the fixed pulley and the movable pulley, a pulley combination group, it can be easily and can change the direction of a force.
The principle is: n is odd, the rope driven hot rolling pulley for starting. The pulley combines the fixed pulley and the movable pulley, which can change the direction of a force, and can easily pull objects. To ensure the safety, quality and safety coefficient, static load reached 3 times. The movable pulley not to change the direction of a force, but it can easily pull the object. Therefore, the hook in hook horizontal thrust bearing support