Shell Holder Retention Device for Ammunition Loading Machine
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Solution Overview
Problem
Existing ammunition loading machines face issues with shell holder retention, leading to unintended lateral removal and misalignment during use, and require user dexterity for precise case alignment, which can result in spoiled production and increased production time and cost due to imprecise spring retention devices and limited alignment references.
Innovation Solution
A loading machine design featuring a removable shell holder with a recess and a retention ring that provides lateral security and an O-ring for friction fit, along with a flat upper surface guiding case insertion, to secure the shell holder against lateral removal and facilitate easier alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire spring is used to retain the shell holder, then the shell holder can be held against lateral removal, but the dimensional and strength variations of the spring cause imprecise retention and require pre-assembly inspection
Solution Approach 1:
The patent replaces the reusable wire spring with a disposable retaining ring that is formed as a single integrated piece. The retaining ring is discarded after a limited number of uses (typically one to five times) when it becomes worn or deformed, eliminating the need for inspection and ensuring consistent performance during its service life.
Solution Approach 2:
The patent changes the physical state and properties of the retention element by forming it from a flat sheet of material that is then radially expanded to create an elastic ring. This manufacturing process creates a retaining ring with uniform dimensional characteristics and consistent elastic properties, eliminating the variations inherent in wire spring fabrication.
2Strength
If the shell holder is robustly secured to the ram, then axial forces are resisted, but lateral removal during use can still occur
Solution Approach 1:
The patent combines two different retention mechanisms into a composite retention system: the pocket with undercut groove provides axial retention, while the separate retaining ring provides lateral retention. This composite approach allows each element to be optimized for its specific function without compromise.
3Manufacturing precision
If the groove for case insertion is small, then precise alignment is required, but this makes it difficult for the user to see and align the case
Solution Approach 1:
The patent extends the alignment function from a one-dimensional groove into a two-dimensional plane by providing a flat upper surface that is coplanar with the groove opening. This gives the user a large visible area to align the case before it enters the narrow groove, separating the alignment function (large surface) from the insertion function (narrow groove).
Solution Approach 2:
The flat upper surface acts as an intermediary between the user's view and the narrow groove. It provides a visible reference plane that guides case alignment without requiring the user to directly see or manipulate the small groove opening, thus mediating between the precision requirement and user capability.
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 enhances shell holder retention and alignment, reducing production errors and costs by providing a secure and intuitive method for inserting casings, thereby improving the precision and efficiency of ammunition manufacturing.
Implementation Method 1
an internal O-ring that compressibly surrounds the end of the ram, to provide a friction fit and allow for variations of size of the ram, holds and centers the retaining element on the ram
Data Source
AI summary
An ammunition manufacturing machine has a frame with a die receptacle, and a reciprocating ram having a free end movable toward and away from the die receptacle. The free end of the die receives a removable shell holder having a recess shaped to receive the base of a casing. The recess has a flat floor portion, and the shell holder is removable along a path lateral to the axis of the ram's motion. A retention element removably encompasses at least part of the shell holder and of the free end of the ram, so that the shell holder is secured by the retention element against lateral removal. The retention element may have a flat upper surface aligned with the floor of the shell holder recess, to provide a guide for sliding the case into the shell holder. The retention element may also have an internal O-ring that compressibly surrounds the end of the ram, to provide a friction fit that holds the retaining element on the ram.