accompanying fig1 schematically depicts a perspective view of a regenerator structure 10 showing an overhead crane apparatus 50 in accordance with an embodiment of the present invention . as is known , the regenerator structure 10 is constructed of large pre - cast refractor blocks stacked on a foundation to thereby side and end walls 16 , 18 , respectively . it will be appreciated that the regenerator structure 10 is used in operative combination with a glass furnace ( not shown ). the regenerator structure 10 generally depicted in the accompanying figures is of a type used for side - fired glass furnaces . however , the attributes of the embodiments of the invention to be described herein are equally applicable to other glass furnace designs , e . g . end - fired glass furnaces . the regenerator structure 10 includes a series of ports ( not shown ) which are used to introduce pre - heated combustion air into the glass furnace ( not shown ) or to exhaust combustion gas from the furnace depending on the operational cycle . the top of the regenerator structure 10 is capped with crowns ( a representative few of which are noted by reference numeral 10 - 2 ). the walls 16 , 18 are structurally supported by external upright structural beams known colloquially as buck stays 20 . as is known , the buck stays 20 are compressively held against the walls by means of tie rods ( not shown ) extending between opposed pairs of buck stays 20 both latitudinally and longitudinally relative to the regenerator structure 10 . the overhead crane apparatus 50 in accordance with an embodiment of the invention is depicted as including cross - support beams 54 latitudinally spanning the regenerator structure 10 . the cross - support beams are preferably attached to a lower roof support beam 57 associated with a building ( not shown ) housing the refractory structure 10 and extending longitudinally relative thereto . attachment of the cross - support beams 54 to the lower roof support beam 55 may be accomplished by any convenient means , e . g ., clamping , riveting , welding or the like , which does not weaken the structural integrity of the lower roof support beam 55 . the cross - support beams 54 are further supported from upper roof trusses or like structures ( not shown ) associated with the building housing the refractory structure 10 by opposed pairs of suspension supports 57 , e . g ., tensioned suspension cables and / or rigid support beams ). one end of the suspension supports 57 is attached to a respective lateral end of a cross - support beam 54 while the opposite end thereof is attached to portion of a correspondingly positioned upper roof truss or like structure . the cross - support beams 54 dependently support a pair of runway beams 56 between which is connected a travelling bridge beam 58 . the bridge beam 58 includes an overhead travelling hoist system 60 . according to preferred embodiments , the runway beams 56 are supported in a cantilever manner by the end - most cross - support beams 54 so that the terminal end portions of such runway beams 56 extend beyond the wall 18 of the regenerator structure 10 thereby enabling access to refractory structures or other heavy equipment therebelow . suitable operator controlled motors ( not shown ) are provided with the bridge beam 58 to allow it to reciprocally travel along the runway beams 56 in a longitudinal direction of the regenerator structure ( i . e ., in the direction of arrow a 1 in fig1 ). similarly , operator controlled motors ( not shown ) are provided with the hoist 60 to allow it to travel reciprocally along the bridge beam in a latitudinal direction of the regenerator structure 10 ( i . e ., in a direction of arrow a 2 in fig1 ). the hoist 60 may be connected to a suitable lifting sling or the like to allow refractory elements ( e . g ., checker bricks , refractory blocks , refractory bricks and the like ) to be lifted up and into the interior of the regenerator structure 10 , e . g ., by suitably operating the bridge beam 58 and hoist 60 so as to travel in the directions of arrows a 1 and a 2 while simultaneously causing the hoist 60 to raise or lower the secured load ( i . e ., in a direction transverse to arrows a 1 and a 2 ). in such a manner , therefore , the checker bricks within the regenerator structure 10 may be replaced and / or refractory blocks / bricks associated with the walls 16 and / or 18 may be installed as may be needed . although pairs of runway beams 56 are depicted in the accompanying drawing fig1 - 2 as supporting a travelling bridge beam 58 , the latter in turn supporting the hoist 60 , the present invention could be embodied in one or more monorail systems whereby the travelling hoist 60 is carried by a monorail extending the lengthwise extent of the refractory structure . in such an embodiment , the monorail may be connected directly to the cross - support beams 54 or may be connected thereto via suitable hangers as described more fully in commonly owned u . s . application ser . no . 14 / 859 , 820 filed sep . 21 , 2015 ( atty . dkt . no . bhd - 6141 - 35 , the entire content of which is expressly incorporated hereinto by reference ). therefore , although the embodiments have been described in relation to a cross - fired glass furnace system , the principles of the invention may likewise be embodied in any glass furnace design , such as float furnaces , end - fired furnaces , unit melters with recuperators and electric furnaces with shelf , sidewall or bottom electrodes . it will therefore be understood that the description provided herein is presently considered to be the most practical and preferred embodiments of the invention . thus , the invention is not to be limited to the disclosed embodiments , but on the contrary , is intended to cover various modifications and equivalent arrangements included within the spirit and scope thereof .