Thomas A Yoo

US Patent:

20200325726, Oct 15, 2020

Filed:

Apr 10, 2019

Appl. No.:

16/380173

Inventors:

Thomas YOO - Garden Grove CA, US

International Classification:

E06C 7/18
E06C 1/393

Abstract:

A ladder with a first guardrail locking system having a first pair of side rails with a first set of steps and a second pair of side rails with a second set of steps. The two sets of side rails are rotatably joined together by a pair of hinges at a first pair joining sections and a second pair joining sections. The first pair joining sections and the second pair joining sections have joint points such as indentations which engage the locking key of a first guardrail so that the first guardrail may be fixedly attached to the joining sections.The ladder may also have a second guardrail, wherein the second guardrail is attached to the first guardrail so that two guardrails form a ring around a user standing on a foldable stand of the ladder.

US Patent:

20200063493, Feb 27, 2020

Filed:

Aug 21, 2018

Appl. No.:

16/107729

Inventors:

Thomas YOO - Garden Grove CA, US

International Classification:

E06C 7/18

Abstract:

A ladder with a guardrail is provided. The U-shaped guardrail has a center arm portion and two side arm portions. Each slot is provided through a side arm portion and has an elongated oval shape. Each hinge center bolt is disposed through a slot and engages a side arm portion to a hinge rotatably. The guardrail lock is disposed at the side arm portion, and the guardrail lock comprises first and second locks, a center rivet, a pair of stopper pins, and a torsion spring. The first or second lock has a guiding curve portion, a circular locking portion, and a through-hole. The center rivet is queued through the through-holes and fixes the first and second locks to the side arm portion rotatably and fixed to the side arm portion. The first and second locks receives and is locked to locking pins on top portions of the side rail.

US Patent:

20190390518, Dec 26, 2019

Filed:

Jun 25, 2018

Appl. No.:

16/017586

Inventors:

Thomas YOO - Garden Grove CA, US

International Classification:

E06C 7/42
F16C 11/04
E06C 1/18

Abstract:

A ladder stabilizer is provided, comprising an extension bar portion, a main arm portion, a brace bar portion, teeth strips, and levers. The extension bar portion is enclosed by an outer wall surface, an inner wall surface, and two side wall surfaces, and having upper and lower end portions. The main arm portion has upper and lower end portions configured for a telescopic connection. The brace bar portion has first and second end portions, and the first end portion is connected to the side portion at a lower position, and the second end portion is connected to the extension bar portion at a middle position. The teeth strips are fixed to lower portions of the two side wall surfaces of the main arm portion. Each lever has latching and releasing ends, installed on the two side wall surfaces of the extension bar through two spring-loaded hinges.

US Patent:

20190383100, Dec 19, 2019

Filed:

Jun 18, 2018

Appl. No.:

16/010918

Inventors:

Thomas YOO - Garden Grove CA, US

International Classification:

E06C 7/06
E06C 1/18
F16B 7/10

Abstract:

A rung lock assembly is provided for a ladder, and comprises rung lock portions, a pinion gear, compression springs, a rung body, a rung cover, a center bolt, a spacer, and a fastener portion. Each of the rung lock portions comprises a rod portion, a rack block fixed to the rod portion, a locking portion, a holding portion connecting the rod portion to the locking portion so that the rod portion is disposed in parallel with the locking portion and configured to be held and pulled by a user's hand, and the rung lock portions are anchored by guide plates and disposed in parallel with each other. The pinion gear is disposed between and engaging the rack blocks, so that the rung lock portions translate outwards or inwards together. The distance between the locking portion is increased in both directions simultaneously by pulling one of the holding portions.

US Patent:

20170183881, Jun 29, 2017

Filed:

Aug 30, 2016

Appl. No.:

15/252107

Inventors:

Thomas YOO - Garden Grove CA, US

International Classification:

E04G 1/34
E04G 5/16
E04G 1/22
E04G 1/30

Abstract:

A collapsible work platform includes toprails engaging fixedly to a platform, backrails engaging the toprails pivotally through a hinge at an end portion of the pair of toprails, frontrails engaging the toprails pivotally through a hinge at the other portion of the toprails, link bars engaging the toprails pivotally, a footstep engaging the link bars and the frontrails pivotally, and braces engaging the backrails and the frontrails, and the toprails pivotally through hinges. Each of latching plates having a latching portion engages fixedly the end portions of the backrails and the frontrails maintaining the deployed state by the braces. Each of stopper blocks engage protrudingly an inner side and an outer side of one end and the other end of the toprails, so that the latching portion of the latching plate contacts and engages fixedly and the backrails and the frontrails are not deployed further beyond a certain point.

US Patent:

20150027810, Jan 29, 2015

Filed:

Jul 24, 2014

Appl. No.:

14/340150

Inventors:

Thomas YOO - Garden Grove CA, US
Jong Deok LIM - Seoul, KR

International Classification:

E06C 1/393
E06C 1/387
E06C 7/50

US Classification:

182 27

Abstract:

A combined stepladder and work platform assembly is provided. The assembly comprises a top frame having two side rails and footplate, a back frame pivotally attached to the back side of the top frame and having two side rails, and a front frame pivotally attached to the front side of the top frame and having two side rails. Link bars are provided so that they maintain steps horizontal together with the side rails of the front frame. Four braces secure the back frame and front frame with the top frame at a certain angle when the assembly is used as a work platform. The front frame, the top frame and the back frame form a triangular shape while the back frame is parallel to the floor when the assembly is used as a stepladder.