If a pound weight be suspended by a string passing over pulley, in descending through io ft.
The smoother we make the pulley the more nearly does the amount of useful work which the weight is capable of doing approach ro foot-pounds, and if we take into account the work done against the friction of the pulley, we may say that the work done by the descending weight is ro foot-pounds, and hence when the weight is in its elevated position we have at disposal r o foot-pounds more energy than when it is in the lower position.
Then to the paying-out drum P, from it to the dynamometer D, and finally to the stern pulley, over which it passes into the sea.
1070 I 060 960 950 930 911 889 883 858 825 823 810 781 771 753 745 727 722 705 681 668, of squares and cubes, calculated from 1 to 60, have been found at Senkera, and a people who were acquainted with the sun-dial, the clepsydra, the lever and the pulley, must have had no mean knowledge of mechanics.
The forward feed is given by a chain winding upon a drum, which hauls upon a pulley fixed to a prop about 30 yds.
It is also customary to use a stretching pulley to keep the rope strained when the pull of the load diminishes.
This is done by passing a loop at the upper end round a pulley mounted in a travelling frame, to which is attached a weight of about 15 cwt.
A flexible steel band, lined with wood blocks, is gripped on the motor fly-wheel or pulley by a screw A, which, together with W, is adjusted to hold the brake steady.
Two equal sprocket wheels Q 1, Q 2, are fastened, the one to the spring pulley, the other to the shaft.
A recording drum or integrating apparatus may be arranged on the pulley frames.
When a belt, in which the maximum and minimum tensions are respectively P and p lb, drives a pulley, the torque exerted FIG.
A tuning-fork or a bell-glass, a silk or cotton thread, the other extremity being either fixed or passing over a pulley and supporting weights by which the thread may be stretched to any degree required.
Their lower articular surfaces, instead of being pulley-like, with deep ridges and grooves, as in other Artiodactyla, are simple, rounded and smooth.
A belt tends to move towards that part of a pulley whose radius is greatest; pulleys for belts, therefore, are slightly swelled in the middle, in order that the belt may remain on the pulley, unless forcibly shifted.
A belt when in motion is shifted off a pulley, or from one pulley on to another of equal size alongside of it, by pressing against that part of the belt which is moving towards the pulley.
The effective radius, or radius of the pitch-circle of a circular pulley or drum, is equal to the real radius added to half the thickness of the connector.
When the a,ces of a pair of pulleys are not parallel, the pulleys should be so placed that the part of the belt which is approaching each pulley shall be in the plane of the pulley.
The pulley or sheave FG has a weight W
In either case the tangential force, whether effort or resistance, exerted between the band and the pulley is their mutual friction, caused by and proportional to the normal pressure between them.
The strap is usually of iron, and the pulley of hard wood.
The following empirical formulae for the stiffness of hempen ropes have been deduced by Mono from the experiments of Coulomb: Let F be the stiffness in pounds avoirdupois; d the diameter of the rope In inches, fl = 48d2 for white ropes and 35d2 for tarred ropes; r the effectire radius of the pulley in inches; T the tension in pounds.
When the cones are pressed together or engaged, their friction causes the pulley to rotate along with the shaft; when they are disengaged, the pulley is free to stand still.
In the friction-clutch, a pulley loose on a shaft has a hoop or gland made to embrace it more or less tightly by means of a screw; this hoop has short projecting arms or ears.
When the clutch is moved towards the hoop, its arms catch those of the hoop, and cause the hoop to rotate and to communicate its rotation to the pulley by friction.
It works in conjunction with the disk and scroll, the cones, or the expanding pulley, to impart an intermittingly variable speed to the bobbin (each layer of the bobbin has its own particular speed which is constant for the full traverse, but each change of direction of the builder is accompanied by a quick change of speed to the bobbin).
She had not yet gone to bed when the Rostovs arrived and the pulley of the hall door squeaked from the cold as it let in the Rostovs and their servants.
At that moment they heard the sound of the door pulley and footsteps in the hall and anteroom, as if someone had arrived.