Weights on rods hung by cords; centres of gravity

Load carried by the upper cords of a suspended rod

To know what the upper cords bear, together with the weights hung on them, one must know either the character of the cord spacings or the true value of each weight. The rod is first made proportional to its opposite spacings, and only then are the sustaining cords considered.

Finding the combined centre of gravity

Divide the rod a n into as many parts as there are hung weights and find their centre at c (here 4). Divide the upper cord span likewise into 4, then see how much nearer the lower centre of gravity lies to one cord than the other; by that much one cord bears more than the other. In the tenth figure a is the centre of the two weights, n the centre of the rod, and m the centre of all the gravities.

Weight turning on a single cord

A weight attached to a single cord and turned circularly between up and down gives the more weight to its support the faster it goes. Nearby, the effort of the motor at n is the same in raising as in lowering.

A weight bearing on a screw and its nut

The weight loads only the half of the screw turned toward it. The teeth of the screw, with those of the nut ('mother') that clothes them, are pressed downward toward the centre of the weight and thrust up on the opposite side, so the weight increases the motor's effort and stresses the teeth with two contrary forces.

Foglio 274 a Recto

Prima colonna. Terza figura coi numeri dei pesi:

Quarta figura :

Sesta figura:

Seconda colonna. Terza figura:

Quarta figura con:

Quinta figura con:

Sesta figura:

Ultima figura:

Terza colonna. Prima figura: 2)

Seconda figura

Terza figura:

Quarta figura:

Quinta figura:

Sesta figura:

Settima figura:

Ottava figura con:

Decima figura:

Undecima figura, corda con peso:

Ultima figura, corda con peso ruotante:

Quarta colonna. Seconda figura:

Terza figura, asta composta 5)

Quarta figura:

Quinta figura:

Sesta figura:

Settima figura:

Ottava figura

Nona figura:

Foglio 274 b Recto

Dall'alto. Seconda figura con:

Terza figura con:

Quarta figura con:

Sheet 274a, recto

First column. Third figure, with the numbers of the weights:

Fourth figure:

Sixth figure:

Second column. Third figure:

Fourth figure, with:

Fifth figure, with:

Sixth figure:

Last figure:

Third column. First figure: 2)

Second figure

Third figure:

Fourth figure:

Fifth figure:

Sixth figure:

Seventh figure:

Eighth figure, with:

Tenth figure:

Eleventh figure, cord with weight:

Last figure, cord with rotating weight:

Fourth column. Second figure:

Third figure, composite rod:

Fourth figure:

Fifth figure:

Sixth figure:

Seventh figure:

Eighth figure

Ninth figure:

Sheet 274b, recto

From the top. Second figure, with:

Third figure, with:

Fourth figure, with:

On this page

Load carried by the upper cords of a suspended rod

Finding the combined centre of gravity

Weight turning on a single cord

A weight bearing on a screw and its nut