Abstract: A collapsible ladder includes two vertical stiles with rungs disposed therebetween. Each stile is formed by a plurality of telescopically collapsible columns. Each collapsible column has a bottom opening, an inner wall and a cover to cover the bottom opening. The cover has a small cylindrical portion and a large cylindrical portion with a peripheral surface located under the small cylindrical portion. The small cylindrical portion is inserted into the bottom opening of a column The large cylindrical portion is exposed outside of the column and inserted inside of a next lower column. A sealing ring is disposed inside a annular groove and touches the inner wall of the next lower column when the stile is extending or collapsing. One or more air ducts are provided in the cover. A first air opening iarranged above the large cylindrical portion in correspondence with an opening in a lower wall part of the column.

Abstract: A collapsible ladder includes two vertical stiles with rungs disposed therebetween. Each stile is formed by a plurality of telescopically collapsible columns. Each collapsible column has a bottom opening, an inner wall and a cover to cover the bottom opening. The cover has a small cylindrical portion and a large cylindrical portion with a peripheral surface located under the small cylindrical portion. The small cylindrical portion is inserted into the bottom opening of a column The large cylindrical portion is exposed outside of the column and inserted inside of a next lower column. A sealing ring is disposed inside a annular groove and touches the inner wall of the next lower column when the stile is extending or collapsing. One or more air ducts are provided in the cover. A first air opening iarranged above the large cylindrical portion in correspondence with an opening in a lower wall part of the column.

Abstract: There is provided a collapsible ladder having several collapsible ladder sections, where each or at least part of the ladder sections comprises two hollow ladder bars arranged parallel to each other and interconnected at an upper end by a rung, and where each collapsible ladder section is telescopically inserted into a lower ladder section. Each ladder bar of a collapsible ladder section has a locking hole adjacent the lower end part of the ladder bar and an extension below the locking hole, and retaining mechanisms are provided in at least part of the rungs for locking the collapsible ladder sections relative to one another when the collapsible ladder sections are extended. Each of or part of the retaining mechanisms comprises a locking pin, which can be brought into an extended and locked position in order to engage a corresponding locking hole provided in the ladder bar of a ladder section positioned there above, and are lease part for bringing the locking pin into a retracted and unlocked position.

Abstract: There is provided a collapsible ladder having several collapsible ladder sections, where each or at least part of the ladder sections comprises two hollow ladder bars arranged parallel to each other and interconnected at an upper end by a rung, and where each collapsible ladder section is telescopically inserted into a lower ladder section. Each ladder bar of a collapsible ladder section has a locking hole adjacent the lower end part of the ladder bar and an extension below the locking hole, and retaining mechanisms are provided in at least part of the rungs for locking the collapsible ladder sections relative to one another when the collapsible ladder sections are extended. Each of or part of the retaining mechanisms comprises a locking pin, which can be brought into an extended and locked position in order to engage a corresponding locking hole provided in the ladder bar of a ladder section positioned there above, and a release part for bringing the locking pin into a retracted and un-locked position.

Abstract: There is provided a collapsible ladder having several collapsible ladder sections, where each or at least part of the ladder sections comprises two hollow ladder bars arranged parallel to each other and inter-connected at an upper end by a rung, and where each collapsible ladder section is telescopically inserted into a lower ladder section. Each ladder bar of a collapsible ladder section has a locking hole adjacent the lower end part of the ladder bar and an extension below the locking hole, and retaining mechanisms are provided in at least part of the rungs for locking the collapsible ladder sections relative to one another when the collapsible ladder sections are extended. Each of or part of the retaining mechanisms comprises a locking pin, which can be brought into an extended and locked position in order to engage a corresponding locking hole provided in the ladder bar of a ladder section positioned there above, and a release part for bringing the locking pin into a retracted and un-locked position.

Abstract: A ladder having several collapsible ladder sections (100), each comprising two hollow ladder bars (102, 103) arranged parallel to each other and interconnected by a rung (104), where each collapsible ladder section is telescopically inserted into a lower ladder section. Each ladder bar of a collapsible ladder section has a locking hole (111) and an extension (112) below the locking hole. Retaining mechanisms (106) are provided in the rungs for locking the collapsible ladder sections relative to one another, and the retaining mechanisms comprise a locking pin (108), which can engage a corresponding locking hole provided in the ladder bar of a ladder section positioned there above. At least part of the collapsible ladder sections have a non-locking slot or groove (101) formed in the extensions of the ladder bars, where the slot reaches from a distance below the ladder bar to the bottom of the ladder bar.

Abstract: A ladder having several collapsible ladder sections (100), each comprising two hollow ladder bars (102, 103) arranged parallel to each other and interconnected by a rung (104), where each collapsible ladder section is telescopically inserted into a lower ladder section. Each ladder bar of a collapsible ladder section has a locking hole (111) and an extension (112) below the locking hole. Retaining mechanisms (106) are provided in the rungs for locking the collapsible ladder sections relative to one another, and the retaining mechanisms comprise a locking pin (108), which can engage a corresponding locking hole provided in the ladder bar of a ladder section positioned there above. At least part of the collapsible ladder sections have a non-locking slot or groove (101) formed in the extensions of the ladder bars, where the slot reaches from a distance below the ladder bar to the bottom of the ladder bar.

Abstract: In a system and method for charging a rechargeable battery having a protection circuit, the rechargeable battery operates according to a model that includes an ideal battery and an internal resistance. In the model, an electrode voltage develops across the ideal battery. An internal voltage drop equal to the difference between this electrode voltage and the battery voltage is developed across the internal resistance. The battery is charged with a charging voltage that may exceed the threshold voltage and the electrode voltage. The charging system and method ensures that (1) the voltage at the protection circuit is kept below the threshold voltage and (2) the electrode voltage is kept below the end-of-charge voltage.

Abstract: In a system and method for charging a rechargeable battery having a protection circuit, the rechargeable battery operates according to a model that includes an ideal battery and an internal resistance. In the model, an electrode voltage develops across the ideal battery. An internal voltage drop equal to the difference between this electrode voltage and the battery voltage is developed across the internal resistance. The battery is charged with a charging voltage that may exceed the threshold voltage and the electrode voltage. The charging system and method ensures that (1) the voltage at the protection circuit is kept below the threshold voltage and (2) the electrode voltage is kept below the end-of-charge voltage.