This invention generally relates to an apparatus for securing attachments to chains and more specifically to apparatus for securing lugs used in cartoning machines to conveyor chains to position and carry cartons travelling through the cartoning machine. 
Cartoning machines to which the present invention is applied have been used in the packaging industry for many years.  Typically, these cartoning machines feed flat folded carton blanks from a magazine, one at a time, onto a conveyor which carries them to a fill station.  The carton blank includes upper and lower major walls interconnected by leading and trailing side walls and are erected, as they are fed and conveyed, into a tubular rectangular form with the axis of the tube oriented transversely to the machine direction, When the carton is erected, it is typically captured between a leading transport lug mounted on an endless conveyor chain and a trailing transport lug mounted on another endless conveyor chain.  The two endless conveyor chains carry the lugs and erected carton downstream for further processing, i.e., filling, closing and sealing the cartons. 
Examples of such cartoning machines are shown in U.S. Pat.  No.  3,333,514 to Jones and entitled PROGRESSIVE CARTON HANDLING MECHANISM FOR CARTONING MACHINES and U.S. Pat.  No.  3,476,024 to Deering et al.  and entitled APPARATUS FOR ERECTING CARTONS.  In FIGS.  18 and 19 Jones shows transport lugs 12 for capturing and carrying cartons 230 along the conveyor 11 of the cartoning machine.  Deering et al.  show the use of transport lugs 51, 53 to erect and carry cartons 22 along a conveyor chain 48. 
Although neither of the above-mentioned patents disclose the specific fastening method of attaching the transport lugs to the conveyor chain of the cartoning machine, typically conventional fastening means such as pins, rivets, bolts, etc.  have been used to make the attachment between each transport lug and its associated conveyor chain.  For example, the lugs are frequently pinned to the chains via extended chain link pins.  When it is desired to change over the cartoning machine to a different size carton, the transport lugs are moved toward or away from each other via relative motion of the independent carrying chains to accommodate smaller or larger cartons.  Such adjustment, however, is limited by the original lug spacing and it is frequently necessary to detach the lugs from the chains and to remount them.  Thus, one problem associated with such transport lugs has been the necessarily long changeover time required when initially setting the cartoning machine up for a specifically sized carton or during changeover from one size carton to another. 
More specifically, during such set up and/or changeover, it is necessary to remove the transport lugs and change their relative positions along the length of the respective conveyor chains to create pockets between adjacent lugs which accommodate cartons of a specific size.  In other words, the pocket between adjacent transport lugs which receives an erected carton blank must be sized during setup of the machine to snugly receive a carton blank by adjusting the spacing between adjacent lugs forming the pocket. 
The setup operation during which transport lugs are attached to the conveyor chain to form uniformly sized and spaced pockets has typically been a very time consuming process since each transport lug must be attached to the conveyor chain with a typical fastener such as a pin, rivet or bolt.  This setup time involves significant labor costs and machine down time thereby increasing the overall cost associated with using such a cartoning machine. 
Accordingly, it has been an object of the present invention to provide improved transport lugs which can easily and quickly be changed or reset to reduce the labor cost and machine down time associated with carton size setup and changeover of cartoning machines.