The THEORY of MACHINES range enables clear and comprehensive learning of and topics. An understanding of the way in which forces act and react, is fundamental when studying the application of loads on a variety of fixed structures and rotating machinery. The THEORY of MACHINES form a comprehensive range of equipment, equally suitable for demonstration and experimental work.

All the THEORY of MACHINES hardware operates in a standalone mode, with a large number being supplied with Data Acquisition Software.

## HTM1 Wheel and Axle

Wall mounted apparatus for investigating the mechanics of a simple wheel and axle machine. Students are able to obtain equations for the relationship between load and effort, and hence obtain a value for the limiting efficiency of the machine. Velocity ratios can be calculated along with understanding the effect on effort, friction and efficiency with increased load.

## HTM2 Wheel and Differential Axle

Through the use of a wheel and stepped differential axle, students can determine the velocity ratio and comparison with calculated values for simple wheel and differential axle machine.

## HTM7 Gear Tooth Form

The gear form apparatus is designed to show and describe how gear teeth are defined and how basic gears work. It also explains the form of an involute curve and how this is used to create a gear tooth profile.

## HTM8 Cam and Follower Apparatus

This compact bench mounted self contained apparatus enables the observation of the rise and fall of various cams and followers supplied.

## HTM9 Simple Flywheel

Wall mounted apparatus to allow students to verify the second law of motion applied to a flywheel i.e. the relationship between torque and angular acceleration. Students can compare experimental and calculated moments of inertia of a disc as well as study the energy transformations.

## HTM13 Double Epicyclic Gear Train

Wall mounted apparatus for the calculation and experimental observation of the angular velocity ratios within an epicyclic gear train. Students can also obtain the torque ratios and efficiencies of the gear train also.

## HTM17 Crank and Connecting Rod

Apparatus to show the relationship between crank shaft rotation and piston displacement for a fixed "cylinder". The stroke of the connecting rod and hence piston can be adjusted by securing its end to the different fixing points on the radius of the crankshaft.

## HTM21 Castor, Camber, King Pin Inclination

This apparatus represents a scale model of the wishbone and king pin arrangement of a front wheel suspension complete with a wheel on an adjustable stub axle. The king pin assembly includes a steering link to demonstrate how a real car works.

## HTM22 Relationship between Angular and Linear Speeds

A stepped shaft with three diameters is carried in a bracket which then allows the comparison of the angular rotation of a shaft and the tangential speed at the circumference.

## HTM25 Gear Train Apparatus

Understanding the basics of gear trains is important. This apparatus ensures this is done in a simple, visual and durable way. Small, compact and self contained bench top unit for introducing students to gear trains and epicyclic gears.

## HTM38 Disc Brake Apparatus

To carry out experiments to investigate the relationship between the normal force acting on the brake pads, the effective radius of the brake pads and the braking torque.

## HTM66 Static and Dynamic Balancing vibration

A self-contained bench top unit for the analysis of static and dynamic balancing of masses on shafts. Students learn about static and dynamic balancing, force polygons, couple polygons and vectors.

## HTM71 Governors Apparatus

Bench top apparatus to demonstrate the principle of operation of various centrifugal governors of Porter, Proell and Hartnell form. A speed controlled vertical shaft allows the governors to rotate in a vertical plane, with the speed of rotation displayed on a digital meter. Students can observe the effect of speed of rotation, lifted mass, rotating mass and geometry on the lift of the governor. From this the sensitivity of each governor can be recorded and observed. The sleeve mass of the Porter and Proell governor can be adjusted by the weights set supplied. The Hartnell governor sleeve can be adjusted by the different springs supplied. Students plot graphs and record lengths, masses and distances for each governor. A transparent safety guard provides protection against the rotating parts.

## HTM73 Gear Assembly Unit Combined Drives

Based around a rigid, sturdy frame a variety of drive arrangements can easily be interchanged and fixed into position. Bearing blocks ensure excellent, repeatable alignment of the drives along with smooth running. The drive arrangements include dual belt drive, chain drive with tensioner, spur gear train, dual spur gear, compound bevel gear and spur gear, compound worm / wheel gear and bevel gear, rack and pinion with a spur gear drive. A cranked handle operates the drives giving more control and feel for each drive arrangement. The layout of the drives gives an excellent visual indication of motion, direction, velocity, and mechanical action.

## HTM78 Four Bar Chain

A sturdy bench top base, with mounting feet and carry handles, incorporates a disc mounted on ball bearings as a crank. The disc has a protractors angle scale so that the rotational angle can be accurately viewed and measured. The crank pin connecting the crank to the disc can be set at different radii on the disc. The connecting rod and the oscillating lever are connected together in different lengths using quick-fit bolts.

## HTM98 Single Epicyclic Gear Train

The gear train consists of a sun gear in the centre, three planet gears, a planet linkage and an internal or ring gear. The sun gear, ring gear and planet carrier all rotate about the same axis. The planet gears are mounted on shafts that turn in planet carrier and meshes with both the sun gear and the ring gear.

Pulleys fitted with protractors are attached to the input and output shaft so that torque and velocity ratios may be determined. Torques can be applied to the shaft by adding weights on cords wrapped on the pulleys. By Locking pins are used to holding different parts of the apparatus in position. This gives the user different options on gear ratios that can be applied between the input and output shafts.

## HAC14 Vertical Stand

This accessory allows the safe and secure attachment of a large variety of wall mounted experiments from the Hi-Tech Education range of teaching products.

Products per page: