is approximately 39 kg and all the parts can be packed together and carried by one man if required alternative materials which could be used to produce a lighter launch frame include aluminium lithium alloy and composites to deploy a bridge using the equipment designed above the launch frame 50 is first assembled at the required site on the u201c home u201d side of the gap to be crossed and facing in the direction in which it is desired to project the bridge modules 6 this is illustrated schematically in fig1 where the frame 50 has been set up supported on the sill of window 2 of building 3 to deploy a bridge through the window 4 of building 5 when assembling the frame 50 all or only some of the counterbalance arm sections may be used depending on the length of the arms 53 which will be required to counterbalance the maximum load of bridge modules in the frame u2014 or in other words the span of the gap to be crossed therefore number of modules required u2014 and the number of personnel available for the task to start the deployment one or a sub assembly of more typically up to four bridge modules 6 are lifted and loaded into the receiving section of the frame 50 from the rear for example fig1 shows a sub assembly of two bridge modules 6 1 and 6 2 which have been connected together with pins 25 and links 27 fig3 and 4 and loaded into the frame 50 in this position the modules are retained in the frame by the spring biased pins 56.