05.Reversing Mechanism || Transfer, moving, driver mechanism

Angled rack and pinion mechanism used to reverse a work piece.

Video: https://youtu.be/HBz6fkZxAEY

Link to download 3D: http://swiftation.com/6huB

Application Overview

Purpose

• One axis of the linear rack section is driven by a cylinder, the pinions on the other axis are then rotated simultaneously to reverse them to any desired angle. (90° in the example).

Points for use

• The work piece is transferred in and out by the up and down motion of the chucking mechanism on the external unit.
• The stroke is controlled by both the sensor of the cylinder, and a mechanical stopper to ensure the precise workpiece angle.

Target workpiece

• Material: Resin
• External Shape:φ9 x W41mm
• Mass: 3g

Features

Operating specifications · Dimensions

• Workpiece rotation angle: 90°
• Pinion Gear: m1.5, z32, P.C.D. 48mm
• Required Cylinder Stroke: 37.7mm
• System External Shape: W 390 x D 300 x H 106mm

Required accuracy・Load

• Cylinder Thrust: 6.83N or more

Selection criteria of main components

• Cylinder
  • Adopted thin type cylinder for space saving.
• Pinion Gear
  • A pinion gear with a tap hole is used affixed to workpiece jig, so the jig can be rotated.

Design point

Calculation processes for the main components

• Whether the cylinder thrust force can handle the slide-way load and rotation section load is verified below.
• Thrust of cylinder (φ20mm, ST 50mm)
  • Condition value: Slide way total weight m1 = 1.714kg, linear guide friction coefficient μ1 = 0.005 (from catalog), rotating section total weight m2 = 0.688kg, conversion factor to slide motion of rotating section μ2 = 1 (assumed as a slide with a friction coefficient of 1 for safe side), operating pressure of cylinder: 0.2MPa
  • Slide way load: F1 = m1 x g x μ1, thus, F1 = 1.714 x 9.8 x 0.005 = 0.084N
  • Rotating section load: F2 = m2 x g x μ2, thus, F2 = 0.688 x 9.8 x 1 = 6.742N
  • Total load: F = F1 + F2 = 0.084 + 6.742 = 6.83N
  • Pull side thrust of cylinder: F0 = 47N(from catalog)
  • Safety factor: F0/F = 47/6.83 ≒ 6.88

Structure elaboration and design key points.

• This system is effective for a corner section, that requires the reversing of multiple parts on an automated line in single file.
• The workpiece table has a slotted hole in the rotated direction in order to enable the adjustment of the work piece position during rotation.
• Installing a sensor and mechanical stopper in parallel enables precise positioning and angle adjustment of the workpiece. It also reduces the generation of moments by stopping the transmission of cylinder thrust prior to hitting the mechanical stopper.

IDEA NOTE Reversing at the desired angle on 2 axis simultaneously using a rack & pinion mechanism.

1. The unit is linearly driven with 2 racks fixed in parallel and can be reversed on the 2 axis simultaneously for any desired angle of the pinion gear.

IDEA NOTE Radial + thrust

1. Workpiece positioning and rotation are supported by a mechanism combining a radial bearing and a thrust bearing.