Curved Nozzle Rack Guide Layout for Low-Height Bidet Units

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Solution Overview

Problem

Existing sanitary washing devices that advance and retract a nozzle for private part washing are often too tall, leading to space inefficiencies and potential overlap of components, which can complicate design and installation.

Innovation Solution

The sanitary washing device incorporates a nozzle unit with a curved, upwardly convex design that allows the nozzle to be advanced and retract smoothly, a rack and gear system, and a rack guide that prevents vertical overlap of components, positioning the gear and nozzle below the upper end of the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the nozzle unit and drive mechanism are arranged in a conventional linear configuration, then the washing function is achieved, but the device height increases and components may overlap

Engineering Contradiction:
Improvedevice heightVSAvoidcomponent arrangement
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The rack guide is configured with a curved portion that extends and folds back in the longitudinal direction, transforming the linear arrangement into a curved three-dimensional path. This dimensional change allows the rack to move along a curved trajectory, positioning the nozzle unit, gear, and curved portion in different vertical planes, thereby preventing vertical overlap and reducing device height

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The curved portion of the rack guide is positioned behind the gear when viewed in side-view, creating a nested spatial arrangement where components are arranged in sequence along the curved path rather than overlapping vertically. This nesting approach allows efficient use of horizontal space while minimizing vertical height

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the gear and rack are positioned to engage properly for nozzle movement, then the washing function is achieved, but vertical space is consumed leading to increased device height

Engineering Contradiction:
Improvenozzle advancement and retractionVSAvoiddevice height
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The rack guide converts the vertical space requirement into horizontal curvature. The rack moves along a curved path that folds back in the longitudinal direction, allowing the gear-rack engagement to occur in a horizontal plane rather than consuming vertical space. This maintains proper mechanical engagement while reducing device height

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rack guide includes a curved portion that extends and folds back, providing a curved trajectory for the rack movement. This curvature allows the nozzle unit to advance and retract along a smooth arc, maintaining ease of operation while arranging components in a compact vertical profile

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4682318A1Sanitary washing device
Publication Date: 2026.01.21 TOTO LTD
  • EP4682318A1 patent drawingFigure 1
  • EP4682318A1 patent drawingFigure 2
  • EP4682318A1 patent drawingFigure 3

AI summary

A sanitary washing device includes a casing, a nozzle unit, a flexible rack connected to the nozzle unit, a gear configured to engage the rack, a drive motor configured to advance and retract the nozzle unit by moving the rack via the gear, and a rack guide configured to guide the rack. The nozzle unit includes a washing nozzle curved to be upwardly convex. The nozzle unit is configured to advance and retreat between the casing and a toilet. The rack guide includes a curved portion extending and being folded back in a longitudinal direction. the gear is positioned behind the nozzle unit when viewed in side-view. The curved portion is positioned behind the gear when viewed in side-view.