ANAND KUMAR SHRIWASASSISTANT PROFESSOR

DR.C V RAMAN UNIVERSITY , KARGI ROAD KOTA BILASPUR (C.G)

MACHINE TOOL TECHNOLOGY

Design of feed gear box

Classification of feed gear boxes

Feed gear box with Change Gears Feed gear box with Sliding Gears Feed boxes with Gear cone and Sliding Key Feed box with Tumbler Gear(Norton’s Gear) Feed box with Meander’s Mechanism

Feed boxes with Gear cone and Sliding Key

Feed boxes with Gear cone and Sliding Key Positive features:

Compact design which enables 8-10 transmission in a single group. Simple control as all transmissions are engaged by a single lever. Helical gear may be used.

Disadvantages; The key may not stuck at some point. Low rigidity of the driven shaft due to long keyway. Poor location of gears on the shafts as they are thin Inability to transmit large torque.

Use: Small and medium sized lathe and drilling machine.

Feed box with Tumbler Gear(Norton’s Gear)

Feed box with Tumbler Gear(Norton’s Gear) Numbers of gears in driving shaft equals to number of transmission. Positive Features:

Compact design 10-12 transmission may be obtained in one group. Small dimensions as only u+2 gears are required to obtain u feed-rate values. Simple control as all transmission are engaged by a single lever.

Disadvantages: Insufficient rigidity and accuracy of meshing. Possibility of dirt penetrating into the gear box through slot in the housing. Poor lubrication.

Use: Thread cutting lathe (precise setting of required transmission ratio).

Feed box with Meander’s Mechanism

Feed box with Meander’s Mechanism

First gear block on the driving shaft is rigidly mounted. The feed rate obtain at the output shaft from a geometric progression.

Disadvantages: Insufficient accuracy and rigidity of meshing.

It is over come by making gear Zd to mesh directly with large gear of shaft. Use:

Thread cutting lathe.

Feed box with Meander’s Mechanism