by means of a bolt 110 extending through the wall 112 defining the air chamber 103 and into a threaded hole 114 formed within the vertical mount 106 a pair of o ring seals 116 prevent air within the air chamber 103 from escaping around the periphery of the distal end 108 the vertical mount 106 further includes a threaded recess 118 formed at the distal end 120 the threaded recess 118 being adapted to couple a pressure regulator expansion chamber or other source of compressed air or other gas the compressed air is communicated to the air chamber 103 through a passage 122 formed within the vertical mount 106 as with the embodiment illustrated in fig1 the passage 122 is small and restricts air flow from the air source plus requires the air to traverse a 90 degree bend prior to reaching the air chamber 103 a second embodiment of the present invention is illustrated in fig5 and 6 and indicated generally at 130 the air reservoir 130 includes a distal end 132 and a proximal end 134 wherein the proximal end 134 is adapted to mount within the air chamber 103 in the same manner as the vertical mount 106 the air reservoir 130 therefore includes o ring seals 116 and a threaded hole 114 for receiving the bolt 110 the air reservoir 130 includes an air reservoir chamber 136 formed longitudinally therein and sealed on the distal end by a threaded plug 138 air or other suitable compressed gas is supplied to the air reservoir chamber 136 through a threaded passageway 140 an adapter not shown is preferably coupled to the threaded passageway 140 and provides an appropriate mounting surface for the source of compressed air such as a pressure regulator expansion chamber.