IP Library Granted Patent US 12,644,336
Granted Patent B2
US 12,644,336 · App. 17/539,486 · Granted Jun 2, 2026

Step ladder

Inventors: Jeff Skubic (Eden Prairie, MN); Dennis D. Simpson (Plymouth, MN); Ben Williams (Chaska, MN); Yongxue Lu (Shanghai, CN)
Assignee: Tricam Industries, LLC
E06C1/393E06C1/16E06C7/14
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Quick Facts
Patent No.
US 12,644,336
App. No.
17/539,486
Granted
Jun 2, 2026
Kind
B2
Abstract

A ladder including a first frame, a second frame and a platform assembly. The first frame includes one or more fixed steps. The platform assembly includes a first platform pivotably coupled to the first frame, a second platform pivotably coupled to the first frame, a first linkage coupled between the second frame and one of the first platform and the second platform, and a second linkage coupled to the first platform and the second platform. The ladder is movable between a closed position and an open position.

Claims (30)

1 . A ladder, comprising:

a first frame;

a second frame comprising a crossmember;

a platform assembly, including:

a lower platform comprising a stepping surface and pivotably coupled to the first frame;

an upper platform comprising a stepping surface and pivotably coupled to the first frame;

a linkage bar coupled between the second frame and the lower platform;

a tie bar coupled to the lower platform and the upper platform or the first frame,

wherein the ladder is configured to be movable between a closed position and an open position; and

a fixed step having a stepping surface and being arranged below the platform assembly, the fixed step extending beyond a thickness of the first frame in a direction toward the second frame and the fixed step not extending beyond the thickness of the first frame in the opposite direction, wherein the fixed step is configured to be positioned wholly within a boundary defined by combining the thickness of the first frame and a thickness of the second frame when the ladder is in the closed position, wherein the linkage bar is movable with respect to both the lower platform and one of the first frame or second frame when the ladder is moved between the closed position and the open position, wherein the stepping surfaces of the upper platform, lower platform and fixed step are generally parallel to one another when the ladder is in the open position, and wherein the upper platform rests on the crossmember and the tie bar does not extend above the upper platform or below the lower platform when the ladder is in the open position.

2 . The ladder of claim 1 , further comprising a hinge disposed between the first frame and the second frame.

3 . The ladder of claim 1 , wherein the linkage bar is coupled between the second frame and the lower platform, and further wherein the open position of the ladder is limited at least in part by the linkage bar.

4 . The ladder of claim 1 , wherein the open position of the ladder includes the upper platform and the lower platform oriented generally parallel to a surface on which the ladder is located.

5 . The ladder of claim 1 , wherein the first frame and second frame each include a longitudinal axis, and further wherein the closed position of the ladder includes the longitudinal axis of the first frame generally parallel to the longitudinal axis of the second frame.

6 . The ladder of claim 5 , wherein the closed position of the ladder further includes the upper platform and the lower platform oriented generally parallel to the longitudinal axes of the first and second frames.

7 . The ladder of claim 1 , wherein the lower platform is supported in the open position at least in part by the tie bar.

8 . The ladder of claim 1 wherein at least a portion of the platform assembly is configured to be positioned at least partly within a boundary defined by the thickness of the first frame when the ladder is in the closed position.

9 . The ladder of claim 1 wherein at least a portion of the platform assembly is configured to be positioned wholly within a boundary defined by the thickness of the first frame when the ladder is in the closed position.

10 . A ladder, comprising:

a first frame having a thickness;

a second frame comprising a crossmember;

a platform assembly, including:

a lower platform comprising a stepping surface and pivotably coupled to the first frame;

an upper platform comprising a stepping surface and pivotably coupled to the first frame;

a linkage bar coupled between the second frame and the lower platform; and

a tie bar coupled to the upper platform and the lower platform;

wherein the ladder is configured to be movable between an open position and a closed position and wherein the platform assembly is configured to be positioned within a boundary defined by the thickness of the first frame when the ladder is in the closed position; and

a fixed step having a stepping surface and being arranged below the platform assembly, the fixed step extending beyond the thickness of the first frame in a direction toward the second frame and the fixed step not extending beyond the thickness of the first frame in the opposite direction, wherein the fixed step is configured to be positioned wholly within a boundary defined by combining the thickness of the first frame and a thickness of the second frame when the ladder is in the closed position, wherein the linkage bar is movable with respect to both the lower platform and one of the first frame or second frame when the ladder is moved between the closed position and the open position, wherein the stepping surfaces of the upper platform, lower platform and fixed step are generally parallel to one another when the ladder is in the open position, and wherein the upper platform rests on the crossmember and the tie bar does not extend above the upper platform or below the lower platform when the ladder is in the open position.

11 . The ladder of claim 10 , wherein the first frame and second frame each include a longitudinal axis, and further wherein the closed position of the ladder includes the longitudinal axis of the first frame generally parallel to the longitudinal axis of the second frame.

12 . The ladder of claim 11 , wherein the closed position of the ladder further includes the upper platform and the lower platform oriented generally parallel to the longitudinal axes of the first and second frames.

Assignments (3)
CERTIFICATE OF CONVERSION Recorded Feb 6, 2025
From: TRICAM INDUSTRIES, INC.
To: TRICAM INDUSTRIES, LLC
Reel/Frame 070144/0480 →
SECURITY INTEREST Recorded Feb 2, 2025
From: TRICAM INDUSTRIES, LLC
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 070082/0930 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 1, 2022
From: SKUBIC, JEFF; SIMPSON, DENNIS; WILLIAMS, BEN; LU, YONGXUE
To: TRICAM INDUSTRIES, INC.
Reel/Frame 059134/0010 →
Continuity (4)
Continuation 16834561 · Mar 30, 2020
Continuation 14617441 · Feb 9, 2015
Provisional Application 61950287 · Mar 10, 2014
Related Publication 20220162910A1 · May 26, 2022
References Cited (51)
US 2470053A · Salisbury · 1949 [cited by applicant]
US 2650014A · Harrison · 1953 [cited by examiner]
US 2899008A · Larson · 1959 [cited by applicant]
US 3446310A · Alfie · 1969 [cited by applicant]
US 4270463A · Korzon · 1981 [cited by applicant]
US 4485892A · Maloney · 1984 [cited by examiner]
US 5722507A · Kain · 1998 [cited by examiner]
US 5967260A · Spak · 1999 [cited by examiner]
US 6012548A · Kim · 2000 [cited by examiner]
US 6347687B1 · Alim · 2002 [cited by examiner]
US 6390237B1 · Kim et al. · 2002 [cited by applicant]
US 6390238B1 · Gibson · 2002 [cited by examiner]
US 6427805B1 · Gibson · 2002 [cited by examiner]
US 6443261B1 · Gibson · 2002 [cited by examiner]
US 6454050B2 · Gibson · 2002 [cited by examiner]
US 6550579B2 · Gibson · 2003 [cited by examiner]
US 6698699B1 · Bailey · 2004 [cited by applicant]
US 7108103B2 · Meeker · 2006 [cited by examiner]
US 7128187B2 · Simpson · 2006 [cited by examiner]
US 7204343B1 · Seaman · 2007 [cited by applicant]
US D548364S · Skubic · 2007 [cited by examiner]
US D554771S · Skubic · 2007 [cited by examiner]
US 7849967B2 · Gibson · 2010 [cited by examiner]
US 7861826B2 · Meyers · 2011 [cited by examiner]
US 7931123B2 · Moldthan · 2011 [cited by examiner]
US 8997931B2 · Parker · 2015 [cited by examiner]
US D766461S · Moss et al. · 2016 [cited by applicant]
US D766462S · Moss et al. · 2016 [cited by applicant]
US D777350S · Moss et al. · 2017 [cited by applicant]
US 11220862B2 · Skubic et al. · 2022 [cited by applicant]
US 20020017431A1 · Gibson · 2002 [cited by examiner]
US 20040000449A1 · Meeker · 2004 [cited by examiner]
US 20040007424A1 · Simpson · 2004 [cited by examiner]
US 20070181369A1 · Gibson · 2007 [cited by examiner]
US 20070240935A1 · O'Brien · 2007 [cited by examiner]
US 20070284192A1 · Meyers · 2007 [cited by examiner]
US 20110024234A1 · Lin · 2011 [cited by examiner]
US 20130048427A1 · Sordo · 2013 [cited by examiner]
US 20140224585A1 · Russell · 2014 [cited by examiner]
US 20140332316A1 · Tiber et al. · 2014 [cited by applicant]
US 20150090533A1 · Moss et al. · 2015 [cited by applicant]
US 20150159434A1 · Leng · 2015 [cited by examiner]
AU 2007101150 · 2008 [cited by applicant]
FR 2777593 · 1999 [cited by applicant]
FR 2816984 · 2002 [cited by applicant]
WO WO2010084135 · 2010 [cited by applicant]
Polder® 3-Step Ladder. Crate and Barrel, http://www.crateandbarrel.com/polder-3-step-ladder/s451498, accessed May 6, 2015. [cited by applicant]
Cosco Signature Series 6 ft. Premium Aluminum Step Ladder, Home Depot, http://www.homedepot.com/p/Cosco-Signature-Series-6-ft-Premium-Aluminum-Step-Ladder-2061AABLD/203642157, accessed May 6, 2015. [cited by applicant]
Werner 4 ft. Fiberglass Platform Step Ladder with 375 lb. Load Capacity Type IAA Duty Rating. Home Depot, http://www.homedepot.com/p/Werner-4-ft-Fiberglass-Platform-Step-Ladder-with-375-1b-Load-Capacity-Type-IAA-Duty-Ra… [cited by applicant]
Application and File History for U.S. Appl. No. 14/617,441, filed Feb. 9, 2015. Inventors: Jeff Skubic et al. [cited by applicant]
Application and File History for U.S. Appl. No. 16/834,561, filed Mar. 30, 2020. Inventors: Jeff Skubic et al. [cited by applicant]