Reed type mechanical comparator

Reed type mechanical comparator

Reed type Mechanical Comparator

          The instrument used to measure linear displacement of spindle with the help of the reed mechanism is known as reed type Mechanical comparator. It is a device magnifying small motions of spindle.

Constructional details:

• The reed mechanism is frictionless device for magnifying small motions of the spindle.
• It consists of a fixed block `A` which is rigidly fastened to the gauge head case
• The floating block `B` carries the gauging spindle

• The floating block is also connected horizontally to the fixed block by reeds `C`
• A vertical reed is attached to each block with upper ends jointed together
• These vertical reeds are shown in fig by letter `D`
• A pointer is attached to this joint

Working principle:

A linear motion of the spindle moves the floating block vertically upwards. This vertical movement causing the vertical reed on the floating block to slide past the vertical reed on the fixed block. The movement causes both reeds swing through an arc. As the point is nearly an extension of the vertical reeds `M` it swings through a much wider arc.