Nested Hydraulic Cylinder Assembly for Long Stroke and High Closing Force
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Solution Overview
Problem
Hydraulic tools, such as concrete crushers and scrap cutters, face challenges in achieving efficient performance, maneuverability, and compactness due to the trade-off between the performance of the hydraulic system and the dimensions and weight of the frame, limiting the use of more robust and heavier adjusting cylinders in demolition devices.
Innovation Solution
A hydraulic cylinder assembly with a hollow piston rod accommodating an additional cylinder rod and piston body, featuring three cylinder chambers controlled by two valve block assemblies, which results in a more compact, lightweight, and efficient hydraulic system with longer stroke and higher closing forces, enabling quicker cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large and expensive hydraulic adjusting cylinders with valve hydraulics are used, then closing forces and cylinder stroke are improved, but device weight and dimensions increase
Solution Approach 1:
The invention places the second piston/cylinder combination inside the first piston rod, creating a nested configuration where the inner cylinder assembly is housed within the outer piston rod. This nesting approach allows two complete piston/cylinder combinations to occupy the space of a single conventional cylinder, achieving high closing forces and long stroke without proportionally increasing overall dimensions and weight
Solution Approach 2:
The invention transitions from a conventional single-dimension cylinder arrangement to a multi-dimensional nested structure. By utilizing the internal volume of the piston rod as a housing for the second cylinder assembly, the design effectively adds a spatial dimension to the hydraulic system configuration, allowing compact integration of multiple functional elements
2Force
If large and expensive hydraulic adjusting cylinders with valve hydraulics are used, then closing forces and cylinder stroke are improved, but device complexity and cost increase
Solution Approach 1:
The invention merges two separate piston/cylinder combinations into a single integrated assembly where the second cylinder is housed within the first piston rod. The valve blocks are strategically positioned with the first valve block on the outer cylinder and the second valve block on the inner cylinder, creating a unified control system that manages both hydraulic chambers through a coordinated valve arrangement
Solution Approach 2:
The nested piston rod serves multiple functions: it acts as the moving element of the first piston/cylinder combination, serves as the housing for the second piston/cylinder combination, and provides structural support for the overall assembly. This multi-functionality reduces the number of separate components needed, simplifying the overall device complexity
3Productivity
If conventional hydraulic cylinders are used, then the system is simpler, but cycle times are longer and productivity is reduced
Solution Approach 1:
The invention enables continuous hydraulic action by providing two independent piston/cylinder combinations that can operate in sequence or parallel. The first piston rod can extend while the second piston rod retracts, and vice versa, allowing continuous material processing without idle cycles, thereby significantly improving productivity
Solution Approach 2:
The invention introduces dynamic control through two independently controllable valve blocks that can switch between different operational modes. The system can dynamically adjust between single-action mode (using only the outer cylinder), dual-action mode (using both cylinders simultaneously), and sequential mode (alternating between cylinders), optimizing performance for different operational requirements
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 solution provides a compact and lightweight hydraulic adjusting cylinder assembly with longer strokes and higher closing forces, enhancing the efficiency and maneuverability of hydraulic tools while minimizing unnecessary pressure loss and cycle time, thus addressing the limitations of existing systems.
Implementation Method 1
a first piston/cylinder combination (10) consisting of a cylinder body (11) provided with a first, closed end (11a) and a second, open end (11b) and a piston body (12) accommodated in the cylinder body (11) and provided with a piston rod (13) extending from a second, open end (11b) of the cylinder body (11), wherein the first piston/cylinder combination (10) is actuable by a pressurized fluid
Data Source
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AI summary
The invention relates to a hydraulic cylinder, for example for use with a hydraulic tool, which hydraulic tool is provided with a frame and an element which is movable with respect to the frame by means of the hydraulic cylinder. A hydraulic tool which is operated by means of a hydraulic cylinder as described above is known from, for example, European patent no. 0641618. This patent discloses a frame which is coupleable to a jib of an excavator or the like and to which an assembly of two jaws can be coupled. One of the jaws is pivotable with respect to the other jaw by means of a hydraulic adjusting cylinder (a double-acting piston/cylinder combination).