Escalator Tread Element Cantilever Arm Design
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Solution Overview
Problem
Conventional tread elements for passenger conveyors, such as escalators and moving walkways, face challenges in minimizing the bending radius in turnaround sections and maintaining a narrow gap between moving tread elements and stationary skirt boards, which complicates space usage and safety, especially when using lateral skirt boards that move with the tread elements.
Innovation Solution
The design incorporates tread elements with a riser panel pivotably connected to the tread, supported by tread chain axles, and cantilever arms that support tread rollers, allowing for a compact configuration where the tread rollers' guide path lies entirely within or outside the tread chain rollers' path, reducing the required lateral space and improving stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral skirt boards moving with the tread elements are used, then the gap between moving and stationary parts is reduced, but the bending radius in turnaround sections becomes excessively large
Solution Approach 1:
The lateral skirt board is divided into a fixed part and a movable part. The movable part is connected to the tread element and can pivot independently, allowing it to follow the tread element's motion while the fixed part remains stationary. This segmentation enables the movable skirt board to maintain proximity to the tread element (reducing gap) without requiring the entire skirt board structure to follow a large bending radius path.
Solution Approach 2:
The lateral skirt board transitions from a completely stationary structure to a dynamic structure with both fixed and movable portions. The movable portion pivots relative to the fixed portion, enabling adaptive motion that reduces the gap between moving and stationary parts while accommodating the turnaround section's bending radius constraints.
2Strength
If the size of tread elements is increased, then the structural strength is improved, but the minimum bending radius of the transition curve becomes undesirably large
Solution Approach 1:
The riser is divided into a fixed riser panel and a movable lateral skirt board. This segmentation allows the tread element to maintain its structural strength through the fixed riser panel while the movable skirt board accommodates the bending radius constraint by pivoting independently during turnaround sections.
Solution Approach 2:
The lateral skirt board is designed as a movable component that pivots relative to the fixed riser panel. This dynamic configuration allows the tread element to maintain its full structural strength while the movable portion adapts to the turnaround section's bending radius, preventing the entire structure from requiring an excessively large bending radius.
3Reliability
If pivotable lateral skirt panels are used, then the gap closure is improved, but both the skirt panels and step chain links require the same length as tread surfaces, leading to large bending radii
Solution Approach 1:
The lateral skirt board is segmented into a fixed part attached to the frame and a movable part attached to the tread element. This segmentation allows the movable part to be shorter than the full tread surface length, pivoting within a compact range that reduces the bending radius requirement while still maintaining effective gap closure.
Solution Approach 2:
The lateral skirt board employs a dynamic pivot connection between its fixed and movable parts. This dynamic mechanism allows the movable part to follow the tread element's motion closely (improving gap closure) without requiring the entire skirt board to have the same length as the tread surface, thereby reducing the bending radius in turnaround sections.
Data Source
AI summary
A tread element (12) for a passenger conveyor (10); the tread element (12) comprising a tread (14) defined by a front side, a rear side, a first lateral side and a second lateral side;a riser (16) comprising a riser panel (18) adjacent the rear side of the tread (14) and pivotably connected to the tread (14);at least one tread chain axle (28) adapted to connect the tread element (12) to the at least one tread chain (22);at least one tread roller (42) adapted to engage with a guide element (36) of the passenger conveyor (10) to adjust the position of the tread (14) with respect to the riser (16); andat least one cantilever arm (40) supported at its one longitudinal side by the tread chain axle (28) and supporting the tread roller (42) at its opposite longitudinal side.