Casters

From
Part: Casters
Caster.scad.png
Designer: Timothy Schmidt
Tools: 3D printers
Parts: Slew bearings, Bolts, Nuts, Washers

Introduction

A caster is an undriven wheel that is designed to be attached to the bottom of a larger object (the "vehicle") to enable that object to be moved.

Casters are used in numerous applications, including shopping carts, office chairs, hospital beds, and material handling equipment. High capacity, heavy duty casters are used in many industrial applications, such as platform trucks, carts, assemblies, and tow lines in plants.

Casters may be fixed to roll along a straight line path, or mounted on a pivot or pintle such that the wheel will automatically align itself to the direction of travel.

Challenges

Determining the best use of space is a process, not an end result. This is especially true when space is at a premium. Furniture and equipment are easier to move when they have wheels. But after you’ve moved them, they should be as stable as possible. So the casters should be easy to lock and unlock with a foot or a hand.

Approaches

Rigid casters

Swivel casters

Subcomponent count and 3D printability of existing caster designs were surveyed. Eleven revisions of test caster were designed, printed, and destructively tested to arrive at a working locking mechanism and feature construction given the constraints imposed by the FDM 3D printing process. Initial designs used 608 roller skate bearings. Later designs increased the number of axes with a preloaded bearing and decreased subcomponent count and cost by integrating printed bearing races into existing printed components.

Current components:

  • 6mm stainless steel balls
  • Stainless M8x130 bolt, nut
  • 2x printed M8 thrust bearings
  • Printed flexible roller (1 hour)
  • Printed hub (1.5 hours)
  • Printed retaining ring (0.5 hours)
  • Printed locking lever (0.4 hours)

Interoperability:

Development targets

  • Locking caster v12

References