Pivot Ratcheting Log Dog for Sawmill Clamping

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Solution Overview

Problem

Existing sawmill technologies face challenges in securely clamping logs due to the need for simultaneous leverage and operation of log dogs, requiring significant strength and coordination, and lack adjustable and pivotable log dog solutions for efficient log handling and clamping.

Innovation Solution

A log dog assembly with a ratcheting mechanism, adjustable height, and pivotable design that allows separate positioning and locking, enabling easier handling and clamping of logs, featuring a slot for height adjustment and teeth for a ratchet-type mechanism, along with a handle for assistance and a coupler for sliding attachment to a framework.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional log dogs are used to clamp logs, then the log can be held firmly in place, but the operator requires significant strength and coordination to simultaneously leverage the log and operate the log dog

Engineering Contradiction:
Improvelog clamping reliabilityVSAvoidoperator effort and coordination
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The log dog is divided into separate functional components: a body portion with a jaw for clamping, a handle portion for operation, and a pivot mechanism. This segmentation allows the operator to manipulate the handle independently while the jaw performs the clamping action, reducing the coordination complexity and physical strength required compared to traditional single-piece log dogs that require simultaneous two-handed operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A pivot mechanism serves as an intermediary between the operator's manual input and the log clamping action. The pivot allows the log dog to rotate and position itself against the log, and incorporates a ratchet mechanism that automatically engages to maintain clamping pressure. This intermediary mechanism transforms simple handle movement into effective log securing without requiring the operator to simultaneously leverage and clamp.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If fixed-height log dogs are used, then the structure is simple, but they cannot accommodate various log sizes

Engineering Contradiction:
Improvelog size accommodationVSAvoidlog dog structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The log dog incorporates a pivot mechanism that allows it to rotate and adjust its position dynamically. The handle portion can be positioned at different angles and heights relative to the body portion, enabling the operator to adapt the log dog to various log diameters and positions. This dynamic adjustability provides versatility for different log sizes without requiring multiple fixed-height log dogs or complex adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The geometry of the log dog, particularly the relative positioning of the jaw and handle portions, can be varied to accommodate different log sizes. The pivot mechanism enables changes in the operational parameters (angle, height, position) of the log dog without changing its fundamental structure, allowing a single design to handle multiple log dimensions.

Inventive Principle:
Principle #35Parameter changes

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

Facilitates safer and easier log positioning and locking, allowing a single operator to manage logs with reduced effort, accommodating various log sizes and improving sawmill operation efficiency and safety, particularly in portable sawmills.

Implementation Method 1

A ratcheting log dog (2) is disclosed, which permits the user to set the log dog (2) against a sawlog (24), and then, leverage the log (24) against log rest(s) (48), while the log dog (2) falls, due to engagement of a ratchet-type mechanism, into a tight locking position

Methodology Applied
Scientific EffectRatchet mechanism: Ratchet

Implementation Method 2

the log dog (2) falls, due to engagement of a ratchet-type mechanism, into a tight locking position

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2746009B1Pivot ratcheting log dog
Publication Date: 2017.07.19 NORWOOD INDUSTRIES INC(CA)
  • EP2746009B1 patent drawingFigure 1
  • EP2746009B1 patent drawingFigure 2
  • EP2746009B1 patent drawingFigure 3

AI summary

A log dog (2) having an elongate body (4) that has a log dog first end (6), a log dog second end (8), a front face (10), a back face (12) and side faces (14). A slot (16) on the side faces (14) extends from proximate the log dog first end (6) to proximate the log dog second end (8). A row of spaced-apart teeth (18) coupled to the body (4) and defining setting notches (20) adapted to enable movement of the log dog (2) in one direction when the log dog (2) is releasably-locked in position during operation. One or more projections (22) can be coupled to the body (4) proximate the log dog first end (6) and protruding from the front face (10) for engaging a log (24). Also disclosed are a log dog assembly (28), a log support and clamp assembly, a sawmill and a kit containing the log dog( 2).