Lifting apparatus

A hoist mechanism comprising:

• a lifting arm comprising a major length with first and second ends, and an upper end section having first and second ends, wherein the first ends of the major length and upper end section join each other in a rigid stationary connection, at a nonparallel angle, such that collectively, the major length and the upper end section define a generally L-shaped structure;
• an extension element slidably connected to the second end of the upper end section in a telescoping relationship, so as to make a length of the upper end section variable;
• a lowermost section slidably connected to the second end of the major length in a telescoping relationship, so as to make a length of the major length variable;
• and
• an actuator having an upper end pivotally connected to a first bracket which is directly connected to the major length of the lifting arm near the first end thereof;
• wherein:
• the major length of the lifting arm comprises longitudinally extending undercut slots having a T-shaped cross-sectional shape with a stem and an arm along side edges of the major length, the stems of the T-shape being exposed at external surfaces of the side edges;
• clamping plates with threaded holes are disposed in the arm of the T-shape;
• and
• the first bracket is clamped to the lifting arm by clamping bolts extending through clearance holes in side walls of the first bracket and engaging the threaded holes.