Metal ladder construction with reinforced side rails
First Claim
1. A lightweight construction for a metal extension ladder(a) a first and second ladder section disposed adjacent one another with ends overlapping, each of which includes:
- (1) a pair of spaced apart side rails comprising an elongated tubular member with a generally rectangular configuration and a structural web disposed within the tubular member for reducing flexure of the side rails;
(2) a series of apertures formed in the side rails at spaced intervals for reducing the weight of the side rails, said series of apertures extending substantially the entire length of the side rails;
(3) a plurality of rungs extending between and attached to said side rails;
(b) means for securing said first and second ladder sections together to allow for relative longitudinal movement between the first and second ladder sections;
(c) means for locking the first and second ladder sections to prevent relative longitudinal movement therebetween.
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Accused Products
Abstract
A metal construction for a ladder includes two spaced apart side rails and a plurality of rungs attached at their ends to the side rails. The side rails each include a generally rectangular side rail tube having angularly disposed reinforcing webs integrally formed within the tube. A plurality of weight reducing apertures are formed in the sidewalls of the tube and are longitudinally spaced at predetermined intervals. The rungs include a tube with an integral reinforcing web extending parallel to the sidewalls of the tube. A portion of the sidewalls of the ladder rung tube are removed by milled slots. The rungs are pivotally attached to the side rails to allow the ladder to be collapsed down to a folded condition.
34 Citations
18 Claims
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1. A lightweight construction for a metal extension ladder
(a) a first and second ladder section disposed adjacent one another with ends overlapping, each of which includes: -
(1) a pair of spaced apart side rails comprising an elongated tubular member with a generally rectangular configuration and a structural web disposed within the tubular member for reducing flexure of the side rails; (2) a series of apertures formed in the side rails at spaced intervals for reducing the weight of the side rails, said series of apertures extending substantially the entire length of the side rails; (3) a plurality of rungs extending between and attached to said side rails; (b) means for securing said first and second ladder sections together to allow for relative longitudinal movement between the first and second ladder sections; (c) means for locking the first and second ladder sections to prevent relative longitudinal movement therebetween. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A lightweight construction for a metal ladder comprising:
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(a) a pair of spaced apart side rails each of which includes an elongated tubular member having a generally rectangular configuration and a structural web disposed within the tubular member for stiffening the same against longitudinal deflection; (b) a series of apertures formed in the side rails and extending substantially the entire length thereof for reducing the weight of said side rails, said series of apertures being arranged in groups with a space between each group; and (c) a plurality of longitudinally spaced rungs extending between the side rails, the rungs having two ends attached to respective side rails in the spaces formed between the groups of apertures. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification