Concrete Access Hatch Skirt with Alignment Tabs
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Solution Overview
Problem
The existing methods for forming access hatches in precast concrete are laborious and time-consuming due to the need for special temporary forms to raise the hatch to desired heights, which are often greater than standard hatch heights, requiring additional form creation and removal processes.
Innovation Solution
A skirt is embedded in the concrete to support the hatch at a predetermined height, featuring alignment tabs for precise placement, retention tabs to secure it within the concrete, and flanges to prevent concrete flow into the hatch opening, allowing the hatch to be formed flush with the concrete surface without needing additional form removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a standard hatch (5 inches high) is used in a concrete slab requiring greater height (8-12 inches), then the hatch cannot reach the desired surface level, but creating and removing temporary forms to raise the hatch is time-consuming and laborious
Solution Approach 1:
The skirt form is pre-configured with a predetermined height (8-12 inches) that matches the desired concrete slab thickness. This preliminary preparation eliminates the need for on-site form creation and removal, as the skirt is already positioned at the correct elevation before concrete pouring, allowing the hatch to be directly placed at the desired height without additional form manipulation.
Solution Approach 2:
The skirt acts as an intermediary structure between the standard hatch and the desired concrete surface level. By embedding the skirt in the concrete form at a predetermined height, it serves as a support platform that raises the hatch to the correct elevation without requiring temporary forms to be created and removed, thus resolving the time loss issue.
2Manufacturing precision
If temporary forms are used to raise the hatch to desired height, then the hatch can be positioned correctly, but the forms must be removed after concrete curing which adds labor and time
Solution Approach 1:
The invention extracts the form removal step entirely from the process by making the skirt a permanent embedded component rather than a temporary form. The skirt is designed to remain embedded in the concrete after curing, eliminating the need for removal operations and associated labor while maintaining precise hatch positioning through its predetermined height design.
Solution Approach 2:
The skirt serves multiple functions: it acts as a form during concrete pouring, provides a support structure for the hatch at the correct height, and remains as a permanent embedded component after curing. This multi-functionality eliminates the need for separate form removal operations, improving ease of manufacture while maintaining positioning accuracy.
3Length of stationary object
If the skirt height is predetermined to match desired concrete thickness, then the hatch reaches the correct surface level, but the skirt must be securely embedded to prevent concrete flow into the opening
Solution Approach 1:
The skirt incorporates local quality features at critical locations: retention tabs extending from the outer surface at specific intervals provide localized anchoring points in the concrete, while flanges at the bottom edge create localized barriers to prevent concrete flow into the opening. These localized features concentrate the embedding and sealing functions where they are most needed, ensuring reliability while maintaining the predetermined height.
Solution Approach 2:
The skirt is pre-equipped with retention tabs and flanges during manufacturing, so that when it is placed in the concrete form, the embedding features are already positioned to prevent concrete flow. This preliminary preparation of embedding features ensures reliable retention and sealing without requiring additional actions during or after concrete pouring.
Data Source
AI summary
A skirt supports an access hatch at a predetermined height as the hatch is formed in concrete. The skirt can be permanently embedded in the concrete. The skirt includes a rigid frame defining a central opening, the frame has an inner surface and an outer surface opposite the inner surface. The frame defines a height between the upper edge and the lower edge. The height of the skirt is predetermined such that the combined height of the skirt and the hatch approximate the desired thickness of the concrete slab. The skirt may include an alignment tab extending from the frame at an angle with respect to the frame, with the alignment tab extending above the upper edge of the frame to guide the hatch into alignment with the upper edge of the frame as the hatch is moved into position on the skirt.