Harrow Tine Coupling for Constant Soil Preload Force
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Solution Overview
Problem
Existing agricultural implements using tine harrows experience variable soil cultivation forces due to non-constant pre-tension spring deflections, leading to uneven cultivation and limited minimum preload reduction.
Innovation Solution
Agricultural implements with a fluid-actuated pretensioning device and a coupling device allowing components to move relative to each other without force, using pistons, dampers, or springs, and connecting elements like wires or rods, ensuring consistent preload force through friction and positive locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If pre-tension springs are used to pre-tension the harrow tines, then the harrow tines can be pre-loaded against the soil, but the pre-tension force varies with deflection leading to uneven soil cultivation
Solution Approach 1:
A coupling device with a coupling element (slot, groove, or travel path) is introduced as an intermediary between the pre-tensioning spring and the harrow tine. This coupling element guides the force transmission such that the spring can deflect while maintaining constant force application to the tine, eliminating the force variation that occurs with direct spring connection
Solution Approach 2:
The force transmission path is segmented into distinct functional elements: the pre-tensioning spring, the coupling device with coupling element, and the harrow tine. This segmentation allows the coupling element to independently manage the deflection motion while the spring maintains constant pre-tension force
2Force
If pre-tension springs with connecting elements are used, then the harrow tines can be pre-loaded, but the minimum preload force is limited by the weight of the spring and connecting elements
Solution Approach 1:
The coupling device acts as a force-free intermediary that decouples the weight of the spring and connecting elements from the harrow tine. The coupling element allows these components to move independently without transmitting their weight force to the tine, enabling the preload force to be reduced to essentially just the tine's own weight
Solution Approach 2:
The coupling device creates a force-free movement area that counteracts the gravitational force of the spring and connecting elements, preventing these weights from acting on the harrow tine during operation
3Adaptability or versatility
If harrow tines are pivotably mounted and pre-tensioned, then the tines can be adjusted and replaced, but the complex force transmission requires precise alignment and assembly
Solution Approach 1:
The coupling element functions as a flexible connection that accommodates misalignment and positional variations through its inherent geometry (slot, groove, or travel path). This flexibility compensates for assembly tolerances and eliminates the need for precise alignment during tine installation
Solution Approach 2:
The coupling device with its force-free movement capability automatically compensates for alignment variations and positions itself correctly during assembly, eliminating the need for manual precision alignment procedures
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
Maintains constant ground force of harrow tines over the travel distance, suitable for vulnerable crops and difficult soil conditions, reducing assembly effort and enabling tool changes.
Implementation Method 1
The preload force can be transferred by friction and/or positive locking
Implementation Method 2
The preloading device can include hydraulically and/or pneumatically actuated preloading elements
Implementation Method 3
The preloading device can include hydraulically and/or pneumatically actuated preloading elements
Implementation Method 4
The preloading elements can also include dampers, springs, or spring assemblies
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to an agricultural implement for soil cultivation comprising a frame, which includes at least one tool frame, a plurality of soil tools, in particular harrow tines, pivotably arranged on the at least one tool frame, and a pretensioning device, in particular fluid-actuated, for pretensioning the soil tools by means of a pretensioning force, wherein the pretensioning device comprises at least one connecting element by means of which at least one soil tool is operatively connected to a pretensioning element of the pretensioning device. According to the invention, a coupling device for connecting two components is arranged between the pretensioning device and a soil-side end of the soil tool, wherein the coupling device is designed such that the connected components are movable relative to each other in at least one area essentially without force.