Electric Lever Cam Layout for Easier Tilt Switch Adjustment
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Solution Overview
Problem
Conventional electric lever devices for construction machines face challenges in attaching and adjusting tilt detecting switches due to their location under the rotation fulcrum, leading to increased size and labor-intensive adjustments, with a high risk of contact with other structures during assembly.
Innovation Solution
The tilt detecting switch is positioned higher than the base portion of the casing, with a cam having a tilt detection engaging portion that moves the switch's acting portion when the operating lever is tilted, allowing easy attachment and adjustment, and the switch can be attached to a bracket at the side or swing direction of the cam for further ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tilt detecting switch is located under the rotation fulcrum of the operating lever, then the switch can detect the neutral position, but the attachment and adjustment of the switch becomes difficult and time-consuming
Solution Approach 1:
The patent inverts the conventional arrangement by positioning the tilt detecting switch above the rotation fulcrum instead of below it. The cam is configured with an engaging portion that extends upward to actuate the switch, reversing the traditional downward arrangement and enabling easier access for attachment and adjustment while maintaining neutral position detection functionality
2Device complexity
If the tilt detecting switch is located at the lower end portion of the electric lever device, then the switch can be positioned near the cam, but the device increases in size in the lower direction
Solution Approach 1:
The patent inverts the vertical arrangement by placing the tilt detecting switch above the base portion rather than at the lower end. The cam structure is designed with an upward-extending engaging portion that contacts the switch, thereby eliminating the need for downward extension and reducing the overall height of the device
3Device complexity
If the tilt detecting switch is located at the lower end portion, then the switch can be close to the cam, but there is a high possibility that the switch contacts other structures during assembly
Solution Approach 1:
The patent inverts the position to above the base portion, moving the tilt detecting switch away from the lower assembly area where it would likely contact other structures during installation. The upward-extending cam engaging portion maintains the functional connection while the elevated position eliminates interference with other components during assembly operations
4Reliability
If two cams are arranged under the rotation fulcrum with limit switches under the respective cams, then the limit switches can detect reverse rotation, but the adjusting work becomes difficult
Solution Approach 1:
The patent inverts the arrangement by positioning the cam and its engaging portion above the rotation fulcrum rather than below it. This allows the limit switch to be accessed and adjusted from above, eliminating the difficulty of working underneath the fulcrum while maintaining the reverse rotation detection capability through the cam's mechanical action
Data Source
Figure 1
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Figure 3A~3B
AI summary
An electric lever device includes: a casing including a base portion attached to a machine main body; a cam supported by a support shaft at the casing and configured to swing in a plane intersecting with a center axis of the support shaft; and an operating lever fixed to the cam and configured to be tilted integrally with the cam in the same plane, wherein: a tilt detecting switch configured to detect tilt of the operating lever is attached to the casing so as to be located higher than the base portion; and the cam includes a tilt detection engaging portion configured to move an acting portion of the tilt detecting switch when the operating lever is tilted from a neutral position.