Rotary Rake Tine Geometry for Better Crop Pickup and Less Breakage

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Solution Overview

Problem

Existing rotary rakes in haymaking machines face issues with pickup and delivery performance, tine breakage, and contamination from self-thrown crop material.

Innovation Solution

A rotary drive design for haymaking machines with specific geometric parameters: angle between 10° and 20° between longitudinal central axes of tine arm sections, trailing spring leg 20 mm to 30 mm shorter than leading leg, and offset of 10 mm to 20 mm between spring legs, along with angles between 50° and 70° with the flange cover plane, and offsets of 60 mm to 110 mm, enhancing intake and discharge while reducing tine breakage and contamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional rotary rake design is used, then basic crop pickup and deposition is achieved, but pickup and delivery performance is insufficient

Engineering Contradiction:
Improvecrop pickup and delivery performanceVSAvoidtine breakage risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the geometric dimensions of the tine arm and spring legs. Specifically, the distance between the longitudinal center axis of the first section and the tip of the trailing spring leg is set to 60-110 mm, the angle between the longitudinal center axis of the first section and the longitudinal center axis of the second section is 10-20°, and the trailing spring leg is 20-30 mm shorter than the leading spring leg. These parameter optimizations simultaneously improve crop pickup/delivery performance and reduce tine breakage risk.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional rotary rake design is used, then crop pickup and deposition is achieved, but contamination from self-thrown crop material occurs

Engineering Contradiction:
Improvecrop intake and discharge behaviorVSAvoidmachine soiling by self-thrown crop material
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent uses parameter changes to control the trajectory of thrown crop material. The angle between the flange cover plane and the longitudinal center axis of the leading spring leg is optimized to 50-70°, and the offset between the longitudinal center axis of the first section and the tip of the trailing spring leg is set to 60-110 mm. These parameters ensure that crop material is thrown forward rather than backward onto the machine, improving intake/discharge while preventing self-contamination.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4646917A1Rotary rake of a haymaking machine
Publication Date: 2025.11.12 CLAAS SAULGAU GMBH
  • EP4646917A1 patent drawingFigure 1~2
  • EP4646917A1 patent drawingFigure 3
  • EP4646917A1 patent drawingFigure 4

AI summary

Rotary rake (10) of a haymaking machine (11), with a flange cover (12), with several tine arms (13) engaging the flange cover (12), wherein each tine arm (13) has a first, radially inner section (13a) and a second, radially outer section (13b) angled relative to the first section (13a), with rake tines (17) engaging the second sections (13b) of the tine arms (13), wherein each rake tine (17) has a first spring leg (18) leading in the direction of rotation of the rotary rake (10) and a second spring leg (19) trailing in the direction of rotation of the rotary rake (10). A longitudinal center axis (20) of the first section (13a) of the respective tine arm (13) and a longitudinal center axis (21) of the second section (13b) of the respective tine arm (13) enclose an angle (α) between 10° and 20°. The trailing spring leg (19) is 20 mm to 30 mm shorter than the leading spring leg (18) of the respective tine (13).Viewed in the direction of the longitudinal center axis (21) of the second section (13b) of the respective tine arm (13), the trailing spring leg (19) and the leading spring leg (18) of the respective tine (13) are offset from each other by between 10 mm and 20 mm.