Dual oblique extractor springs – Patent number CN210533167U – Applied 2019-09-30
This patent states that on traditional AR15 designs, the single extractor spring placed perpendicular to the bolt has a few disadvantages. First, it’s length is limited by the fact that there is a firing pin channel right beneath. This limit in length limits the force that this spring can generate. Second, the traditional AR extractor spring only puts tension on the extractor in the radial direction (i.e., perpendicular to the axis of the bolt). This means that the extractor still has “slop” in the axial direction, where it is allowed to slide back and forth along the length of the bolt a miniscule amount due to the tolerances between parts. This leads to inconsistent ejection. However, the patent also recognizes the benefit of AR extractor designs in that it allows the bolt head to be very small in diameter, leading to a more compact weapon, as opposed to AK extractors that require a large bolt head.
View attachment 81333
Below are the diagrams of the dual oblique extractor springs proposed in the patent:
View attachment 81334
The benefits stated in the patent are:
- Two extractor springs provide a stronger clamping force, leading to better engagement of the extractor on the cartridge rim.
- They don’t interfere with the firing pin channel, so they can be much longer
- The oblique orientation of the extractor springs put forces on the extractor in both the radial and axial direction, effectively eliminating all slop, leading to more consistent ejection.
Additional information that can be inferred from this patent: The bolt head is AR-style, but with only 4 locking lugs. The lengths of the locking lugs (in the axial direction) are not uniform, for unknown reasons. There is also no plunger ejector, so the ejector is fixed. This conclusion can also be supported by the fact that there is a visible slot on the bolt & bolt carrier in the diagram below, taken from one of the other patents posted earlier in this thread (patent CN111426234A):
View attachment 81335
The usual disclaimer applies: these are only patent drawings so there are no guarantees that these features are applied to the actual guns identically to how they’re drawn here. However I am more sure about some features than others. The 4-lug bolt looks pretty reasonable, since the orientation of the top bolt lug matches what can be seen in the following screenshot:
View attachment 81336
The fixed ejector is also a fair assumption, due to the ejection pattern and what looks like two rivets on the left side to mount a fixed ejector to the upper:
View attachment 81337
Currently I don’t think there is any media that confirms the implementation of the dual oblique ejector springs.
dissemble.jpg
