US 8141726

I'll search for information about US patent 8141726 from authoritative sources.

Let me search for CAFC 2026 docket information and the claims of this patent.

Let me search specifically for the claims of US 8141726 and check for any CAFC 2026 case involving this exact patent number.

Based on my searches, I can provide the following summary. I've prioritized the authoritative patent text (Google Patents fetch) and corroborating USPTO-derived sources (Justia, FreePatentsOnline) over any training data.

Bibliographic Data — US 8,141,726 B2

Abstract (verbatim from the patent)

A railroad gondola car has a hopper carried between two trucks. The hopper has convergent end and side slope sheets that feed a bottom discharge. The bottom discharge has a pair of longitudinal doors. The car has a very short draft installation that includes a removable coupler carrier bar, and the main shear plate has a removable draft gear installation cover. The rear draft stop extends longitudinally inboard past the truck center. The couple arrangement includes an AAR Type E shank with an AAR Type F coupler. There is a machinery space above the end section shear plate. It is overhung by the slope sheet that is substantially unobstructed by any other primary structure. The pneumatic cylinder is mounted on an angle in this unobstructed machinery space, oriented longitudinally over the draft sill beneath the main drag link of the mechanical transmission, and above the main pivot of the driving input lever of the transmission. The main lever is bifurcated, and straddles the pneumatic cylinder. The lower portion of the side sheets lies laterally inboard of the stiffener web, while the upper portion lies laterally outboard of the stiffener web. The side slope sheet of the hopper meets the sidewall at the transition of the sidewall sheet from the inside-the-post to the outside-the-post condition.

Independent Claims — Plain-Language Overview

Important caveat: The full text supplied to me (Google Patents fetch) contains the specification and abstract but the claims section was truncated, so I cannot quote the claim language verbatim with complete confidence. The overview below is reconstructed from (a) the specification's "Summary of the Invention" aspects, which in this patent family closely track the independent claims, and (b) claim-language fragments visible in the Justia record. The patent appears to have roughly nine independent claims spanning several distinct inventions:

1. Drag-link/end-slope-sheet claim (hopper car with door linkage): A hopper car with a bottom discharge door and a lengthwise-oriented linkage driven by a drive. When closing, the drag link's displacement is either predominantly parallel to, or at least instantaneously parallel to, the inclined end slope sheet of the hopper — enabling a compact installation under the slope sheet.

2. Tilted actuating cylinder claim: A hopper car whose door-operating linkage is driven by an actuating cylinder oriented lengthwise but with its axis of reciprocation tilted so its stroke includes a vertical component (mounted on an inclined pedestal on the shear plate, between horizontal and the slope-sheet angle, and at least partially overhung by the slope sheet).

3. Low pivot / compact end-section claim: A hopper car where the first pivot arm of the door linkage is pivotally mounted to the end section at a pivot connection located lower than the actuating cylinder (with the cylinder between the main pivot and the drag-link's distal connection in side view).

4. Sidewall stiffener web-continuity claim: A hopper car sidewall where the lower portion of the vertical sidewall stiffener lies laterally outboard of the lower side sheet region while the upper portion lies laterally inboard of the upper region, with the stiffener maintaining web continuity through a continuous side-sheet transition where the hopper's sloped side sheet meets the sidewall (transition at about ¼–⅔ of the wall height).

5. Bifurcated-lever / bracketed-cylinder claim: A hopper car whose door-operating linkage has left and right linkage members mounted on either transverse side of the actuating cylinder, bracketing it (the four-bar closed-loop linkage whose drag-link motion parallels the end slope sheet).

6. Dual-lock claim (over-center + secondary latch): A hopper car with a door actuator, a first lock (over-center lock) preventing door opening when the actuator is inactive, and a second lock that also prevents opening if the first fails, where the second lock moves predominantly crosswise to the actuator's direction of reciprocation (a hinged, spring-biased latch that pivots circumferentially about an axis parallel to the car's lengthwise-vertical plane).

7. Lock-mechanism claim (apparatus): The secondary latch itself — a body with a first fitting (hinge mounting to the datum), a second fitting (cam/cam-follower that intercepts the transmission member and deflects the latch out of the way), and a third fitting (abutment obstructing the transmission to prevent door opening), biased by a spring toward the engaged position and constrained to predominantly crosswise motion.

8. Machinery-space claim (end-section structure): A hopper car whose end section (draft sill, main bolster, shear plate) is overhung by the end slope sheet, defining a machinery space bounded by the slope sheet, shear plate, end post, and corner posts that is free of other primary structure (notably free of "elephant ears"), and which houses the pneumatic actuator and brake reservoir above the draft sill.

9. Draft-gear-installation claim (freight car): A freight car with a draft sill/draft gear pocket, shear plate as the draft sill's upper flange, a removable draft gear carrier plate on the underside, an access aperture in the shear plate and/or a removable coupler carrier bar (with sideways-slidable shaft through the sill webs), rear draft stops welded inboard of the truck center, a short draft sill (truck-center-to-striker < 50 in., e.g., ~38 in.; truck-center-to-coupler-pulling-face < 65 in., e.g., ~53 in.), and short-travel draft gear (deflection < 3 in. to solid).

Litigation / CAFC 2026 Docket Search

I searched for CAFC docket activity specific to 8141726 and found no 2026 CAFC appeal directed to this exact patent number in the results. What I did find:

• CAFC Case 24-1453, National Steel Car Ltd. v. Greenbrier-Concarril LLC et al. (affirmed; "We have considered NSC's arguments and find them unpersuasive... we affirm") — but that appeal concerned US7434519B2 and US7878125B2, not 8141726.
• The Google Patents record flags that the 8141726 patent family has litigation (Darts-ip family 42666563), but I could not verify a specific 2026 Federal Circuit matter for 8141726 itself from my searches.

Uncertainty note: My claim-by-claim mapping is inferred from the specification summary and partial claim fragments rather than the full, verified claims text; if you need verbatim claim language, the USPTO Patent Center record or the Justia full-text page for 8141726 should be consulted directly. The bibliographic data (title, assignee, inventors, dates, abstract) is corroborated across multiple sources and is high-confidence.