The heavy object Stan pulls into the car when Ollie cannot get it moving forward is called a horse anchor or weight. These were used when there was no hitching post available. The weight was tied to the horse's halter or bridle and placed on the ground. This was usually enough to keep the horse in place until its owner returned.
When Ollie brings a bunch of flowers to Mae's apartment, they then change hands 16 times and are never set down or discarded, even at the end of the film.