Hood-Type Dishwasher Variable Hinge Arm for Balanced Lifting
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Solution Overview
Problem
Hood-type industrial dishwashers face challenges in balancing the movement of the hood during opening and closing, requiring excessive operator effort due to varying spring forces and lever arms, leading to inefficient operation and potential hood misalignment.
Innovation Solution
The integration of connecting plates with shaped slots and pins on the levers allows for a variable hinge arm, optimizing the balancing moment throughout the hood's stroke, enabling precise control over the balancing force and reducing operator effort by distributing the spring force through multiple pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional springs and levers are used to counterbalance the hood weight, then the hood can be lifted and lowered with reduced operator effort, but the balancing moment varies with hood position causing excessive effort in initial phase and potential escape in final phase
Solution Approach 1:
The patent applies the dynamics principle by making the lever arm length variable instead of fixed. The connecting member includes multiple connection positions that allow the effective lever arm length to change dynamically as the hood moves through its stroke. This enables the balancing mechanism to adapt to different positions, providing optimal operator effort reduction throughout the entire range of motion rather than relying on a fixed compromise configuration.
Solution Approach 2:
The patent implements parameter changes by varying the geometric parameters of the balancing mechanism - specifically the lever arm length and spring attachment point - as the hood position changes. This is achieved through the connecting member's multiple connection positions, which alter the mechanical parameters of the system dynamically. The spring force and lever arm parameters are adjusted according to hood position to maintain optimal balancing throughout the stroke.
2Reliability
If the spring force is increased to balance the hood weight, then the hood can be held up more effectively, but greater effort is required at the beginning of the closing stroke to overcome the spring force
Solution Approach 1:
The patent uses dynamics to make the lever arm length variable, allowing the mechanical advantage to change with hood position. During the closing stroke, the variable geometry enables the system to provide greater mechanical advantage when spring force is highest, reducing the operator effort required to overcome the spring force and close the hood smoothly.
3Device complexity
If a simple hinge geometry is used, then the device complexity is reduced, but the balancing moment cannot be optimized throughout the entire hood stroke
Solution Approach 1:
The patent resolves this contradiction by implementing a variable geometry hinge mechanism. The connecting member with multiple connection positions transforms a simple hinge structure into a dynamic system where the effective lever arm length changes with hood position. This maintains relative structural simplicity while achieving optimized balancing performance throughout the entire stroke, avoiding the need for complex multi-component mechanisms.
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
This solution achieves optimal balancing of the hood throughout its entire motion, reducing operator effort and allowing customizable balancing, with enhanced reliability and a simple, low-maintenance design.
Implementation Method 1
two pulling springs (7) which at the lower end are attached to the fixed base (1)... the force of the springs depends on their extension
Implementation Method 2
connecting plates (8) arranged between the springs and the levers and equipped with shaped slots (9, 10)... levers (6) being equipped with a plurality of pins (11, 12, 13) that engage alternatively said shaped slots
Implementation Method 3
reduce the effect of the springs in the final stretch where the hood approaches the closure so that it closes autonomously by gravity
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A hood-type industrial dishwasher includes a fixed base with a rear wall that extends upwards and on which a vertically movable hood is mounted through two side rods (14) and a handle (3) that rotates around a horizontal axis (4) being rotatably mounted on brackets (5) fixed to said rear wall, the handle (3) being equipped with rear levers (6) connected to the upper end of balancing springs (7) through connecting plates (8) equipped with one or more shaped slots, and the rear levers (6) being equipped with three pins (11, 12, 13) configured to engage alternatively the upper ends of said shaped slots, the engagement of each pin (11, 12, 13) being made in a more forward or backward position on the connecting plate (8) depending on the position of the hood so as to obtain a variable arm hinge.