Pan-Tilt Head Helical Gear Biasing for Smooth Rotation

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Solution Overview

Problem

Existing pan or tilt heads for camera units experience rattling and vibration when rotation is suddenly changed, and they suffer from unevenness in rotational speed, leading to image blurring.

Innovation Solution

A pan or tilt head configuration that includes first and second helical gears, with a biasing unit that biases the second gear in the rotation axis direction, allowing for smooth rotational drive by removing backlash and reducing torque unevenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a timing belt is used as a rotational drive mechanism, then smooth rotational drive is enabled by removing backlash, but image shakes due to bending and expansion/contraction of the belt when a large lens barrel is driven or stopped at high acceleration

Engineering Contradiction:
Improverotational smoothnessVSAvoidimage shake
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the timing belt mechanical system with a direct drive mechanism where the motor shaft is directly coupled to the lens barrel, eliminating the elastic belt and its associated bending and expansion/contraction issues while maintaining smooth rotational drive

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent removes the timing belt from the drive mechanism, extracting the problematic elastic component that causes image shake during high acceleration, while retaining the essential function of smooth rotational drive through direct motor coupling

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-affected harmful factors

If a scissors gear configuration with strong biasing force is used, then rattling is suppressed by removing backlash, but unevenness in transmission torque becomes large causing speed unevenness and image shake at low speed

Engineering Contradiction:
ImproverattlingVSAvoidspeed unevenness
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent replaces the complex scissors gear mechanism with a direct drive system, eliminating the gear meshing and biasing force requirements entirely, thus removing both the rattling suppression function and the torque unevenness problem simultaneously

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the scissors gear configuration and biasing member from the drive mechanism, eliminating the source of both backlash-related rattling and the associated torque unevenness that causes speed variations

Inventive Principle:
Principle #2Taking out (Extraction)

3Speed

If a scissors gear configuration with weak biasing force is used, then unevenness in transmission torque is reduced, but torque generated by inertia of the lens barrel cannot be maintained causing vibration and image shake during sudden stopping

Engineering Contradiction:
Improvespeed uniformityVSAvoidvibration
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the scissors gear system with direct motor coupling to the lens barrel, eliminating the need for biasing force to maintain torque during sudden stopping, as the direct drive provides immediate inertial resistance without gear meshing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent removes the biasing member and gear mechanism, extracting the system that requires balancing between speed uniformity and vibration suppression, and replacing it with a direct drive that inherently provides both functions

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed configuration effectively reduces rattling and vibration during sudden rotational changes and maintains smooth, constant rotational speed, thereby preventing image blurring.

Implementation Method 1

a biasing unit that biases the second gear in the rotation axis direction

Methodology Applied
Scientific EffectSpring biasing: Spring

Data Source

PatentEP3995890B1Pan or tilt head and imaging device
Publication Date: 2025.04.23 CANON KK
  • EP3995890B1 patent drawingFigure 1
  • EP3995890B1 patent drawingFigure 2
  • EP3995890B1 patent drawingFigure 3

AI summary

In order to provide a pan or tilt head and the like capable of reducing rattling or vibration when a rotation is suddenly changed while reducing the unevenness in rotational speed for smooth rotational drive, there is provided a pan or tilt head including a drive unit which rotates a camera unit in a predetermined direction, first and second gears which rotate around a predetermined rotation axis in the predetermined direction and are coaxial with the predetermined rotation axis, a third gear which meshes with the first and second gears and transmits a driving force from the drive unit, and a biasing unit which biases the second gear in the rotation axis direction, the first gear, the second gear, and the third gear includes helical gears, and the second gear is disposed to be movable in the rotation axis direction with respect to the first gear.