# US 12,007,190 B2 · Connection for connecting upper and lower receiver of a weapon

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- Number: US 12,007,190 B2
- Document ID: US12007190B2
- Status: Granted
- Kind: B2
- Application number: 17/924,421
- Filed: 2021-05-12
- Published: 2023-06-15
- Granted: 2024-06-11
- Earliest claimed: 2020-05-20
- Assignees: Sako Oy
- Applicants: Sako Oy
- Inventors: Christoph Schrödl
- Web page: https://patentgrep.com/patent/US12007190B2

## CPC

- F41A 3/66: Breech housings or frames; Receivers
- F41A: FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE

## Abstract

Connection for connecting an upper receiver to a lower receiver of a weapon, which connection comprises front and rear take-down pins, and through-holes formed in both receivers for inserting the take-down pins through these holes to connect the upper and lower receiver to each other, wherein the rear take-down pin comprises an eccentric portion at its length for tightening the receivers against each other by turning the rear take-down pin.

## Claims

### Claim 1

A connection for connecting an upper receiver to a lower receiver of a weapon, which connection comprises front and rear take-down pins, and through-holes formed in both receivers for inserting the take-down pins through these holes to connect the upper and lower receiver to each other wherein the rear take-down pin comprises an eccentric portion at its length for tightening the receivers against each other by turning the rear take-down pin.

### Claim 2 (depends on 1)

The connection according to claim 1, wherein the eccentric portion of the rear take-down pin is located at least at an area of the through-hole formed in the upper receiver when the rear take-down pin is at its place.

### Claim 3 (depends on 1)

The connection according to claim 1, wherein in a cross-sectional area of the rear take-down pin is smaller within the eccentric portion than outside the eccentric portion.

### Claim 4 (depends on 1)

The connection according to claim 1, wherein in the head of the rear take-down pin is formed a groove or recess for facilitating turning of the rear take-down pin with a tool.

### Claim 5 (depends on 1)

The connection according to claim 1, wherein the connection comprises a first spring-loaded locking pin located in a first channel formed inside a wall of the lower receiver, which first locking pin is configured to prevent complete removal of the rear take-down pin from the lower receiver, and wherein the rear take-down pin comprises a groove extending along part of a length of pin portion of the rear take-down pin into which groove a head of the first locking pin sets and which groove allows the rear take-down pin to be slid through the through-hole formed in the upper receiver.

### Claim 6 (depends on 1)

The connection according to claim 1, wherein the connection comprises a second spring-loaded locking pin located in a second channel formed inside a wall of the lower receiver, which second locking pin is configured to prevent rotating of the rear take-down pin in at least a first rotational direction, and wherein the rear take-down pin comprises a recess for receiving ahead of the second locking pin.

### Claim 7 (depends on 6)

The connection according to claim 6, wherein a plurality of recesses for receiving the head of the second locking pin are formed in circumference of the rear take-down pin, which recesses are formed so, that side walls of the recesses push the head of the second locking pin out of the recess when the rear take-down pin is rotated in an opposite rotational direction in relation to the first rotational direction.

### Claim 8 (depends on 1)

The connection according to claim 1, wherein the connection further comprises a flexible piece fixed inside the lower receiver, which piece deforms when the upper receiver is pressed against the lower receiver in order to at least partially align the through-holes in the upper receiver and in the lower receiver for insertion of the rear take-down pin.

### Claim 9 (depends on 8)

The connection according to claim 8, wherein the flexible piece fixed inside the lower receiver is a rubber piece glued in the lower receiver.

### Claim 10 (depends on 1)

The connection according to claim 1, wherein the through-hole formed in the upper receiver for the rear take-down pin comprises a metal bushing.