Patent ID: 6523320
Filing Date: 2003-02-25
Classification: B66C

Abstract:
A hoisting device having one or more mast parts, each mast part comprising:a plurality of elongated angle bars, each angle bar having a first part including a pair of legs extending at right angles to each other from a corner of the first part and a second part including a pair of legs extending at right angles to each other from a corner of the second part, the first part and the second part being secured together so that an end of one leg of the first part opposite the corner thereof abuts a side of one leg of the second part between the corner of the second part and an end of the one leg of the second part opposite the corner thereof, and an end of the other leg of the first part opposite the corner thereof abuts a side of the other leg of the second part between the corner of the second part and an end of the other leg of the second part opposite the corner thereof, the legs and corners of the first part and the second part of each angle bar defining a conduit that extends between opposite ends thereof; a plurality of elongated cross bars securing the angle bars in spaced parallel relation, each cross bar having opposite ends, with one end of each cross bar connected to one angle bar and with the other end of each cross bar connected to another angle bar; at least one connector having a pair of opposed plate pieces secured by a filler body in spaced parallel relation defining at least one gap therebetween, each plate piece having therein at least one hole which is aligned coaxially with the hole in the other plate piece across the gap, wherein at least one conduit of the mast part adjacent one end thereof slidably receives the one connector with the holes of the plate pieces thereof positioned coaxial with a hole formed in the angle bar defining the one conduit; and an auxiliary frame having at least one coupler including an ear configured to be received in the one conduit of the mast part adjacent the one end thereof and in the gap between the plate pieces of the one connector received in the one conduit, the ear having therein a hole which is aligned coaxially with the holes in the plate pieces of the one connector and the hole formed in the angle bar defining the one conduit for receiving a pin.