are friction devices used to regulate the motion of bodies (slowing them down, holding their speed constant, holding them at rest, etc.)

are friction devices used to connect shafts, that is, speeding up the driven bodies to the same angular velocity as the driving shaft.

have jaws or teeth in two element interlock.

are devices where torque is transmitted by moving fluid.

is one where toque is transmitted by means of magnetic field.

are friction devices in which driving force is transmitted by friction.

utilizes fluid friction in braking.

utilizes strength of electromagnetic fields to cause braking.

are braking devices utilizing friction.

Typical design values for industrial shoe brake: frequent application

Typical design values for industrial shoe brake: average life

Typical design values for industrial shoe brake: infrequent, short-time use

stress-relieved cast iron, or class 30(with alloys, an excellent material).

asbestos and a binder, molded or woven, with or without wire or metal chips, or metal powder, usually brass or copper for improving heat conduction.

have an annular shape.

The wear is proportional to pressure intensity and rubbing speed (also proportional to distance from center of rotation).

The pressure is assumed uniform throughout the surface area and maximum wearing occurs at surface near center of rotation.

Similar to disc clutch, torque transmitted is based on two assumptions; the Uniform Wear Method and the Constant Pressure Method.

is a type of brake where band wraps around the rotating drum.

is a type of band brake where neither ends of the band is fixed at the pivot.

It is used to transmit motion and power between parallel shafts.

is the smaller gear in pair of gears.

is the larger gear in a pair of internal gears.

is a gear of infinite radius.

are equal bevel gears on shafts at 90°.

is a screw gear in pair of a gear, called wheel, in different planes and connecting axes.

is the imaginary circle of the two gears corresponding to two rolling cylinders.

is the point of contact between the two pitch circles, lying in the line of centers, and in the fixed point if the speed ration is constant.

is the diameter of the pitch circles.

is the circle passing through outer ends of the teeth of a gear.

or the root circle, is the circle passing through the bottom of the spaces.

or addendum, is the radius of the addendum circle, minus the radius of the pitch circle.

or dedendum, or root distance, is the radius of the pitch circle, minus the radius of the root circle.

is the dedendum plus the addendum.

is equal to the sum of the addenda of mating gears.

is that portion of the tooth curve outside the pitch circle.

is that portion of the tooth curve inside the pitch circle.

is part of the flank which comes in contact with the face of the tooth of the other gear.

is the length of the gear tooth measured along an element of the pitch surface.

is the distance measured on the line of centers between the addendum circle of one gear and the root circle of the other. This is equal to dedendum of one gear minus the addendum of the mating gear.

is the width of the tooth (arc distance) measured on the pitch circle.

or tooth space, is the arc distance between two adjacent teeth measured on the pitch circle.

is the difference between the space width and the tooth thickness.

is the distance from the center of one tooth to the center of the next tooth, measured on the pitch circle. It is also equal to the tooth thickness plus space width.

the term ordinarily used to designate the tooth size, is equal to the number of teeth divided by the diameter of the pitch circle.

is the arc of the pitch circle where the tooth profile cuts the pitch circle when a pair of teeth first comes in contact until they are in contact at the pitch point. It is the same for both meshing gears.

is the arc of the pitch circle from contact at the pitch point until where the tooth profile cuts the pitch circle when the pair of teeth comes out of contact.

consist of the arc of contact and the arc of recess. It must never be less than the circular pitch , otherwise, one pair of teeth would cease contact before the next pair comes into contact.

is the angle subtended by the arc of approach.

is the angle subtended by the arc of recess.

is the angle subtended by the arc of action. It is equal to the sum of angle of approach and the angle of recess in one gear.

is the line drawn through all points of contact, from the first point of contact, through the pitch point, and to the last point of contact. This may be a straight line or a curved line.

is the angle between the line drawn through the pitch point perpendicular to the line of centers, and the line drawn from the pitch point to the point where a pair of teeth are in contact.

The line drawn from the pitch point to the point where the teeth are in contact, must be perpendicular to a line drawn through the point of contact tangent to the curves of the teeth, that is, the common normal to the tooth curves of all points of contact must pass through the pitch point.