Swift Owner's Handbook - Swift Group

MaintenanceThe AL-KO parking brake system comprisesa handbrake lever mechanism actuating aBowden cable which operates a brake unitassembly contained within the wheel hub.AL-KO provide two types of parking brakesystem on their trailers, with the Bowdencable and the wheel hub brake unit beingcommon to both types.The difference between the systems is thehandbrake mechanism used to actuate theBowden cable.AL-KO’s unique parking brake systemrequires a source of stored energy to lockthe wheel brakes should the trailer start tomove after it has been uncoupled from thetowing unit.This energy source can be provided by eithera spring cylinder charged by hand or by agas filled cylinder acting as an energy store.Each system requires a slightly differentmethod of operation when parking the trailer,though they both operate in the same mannerwhen forward or reverse braking is applied.Spring Cylinder TypeA spring system is attached to the linkbetween the handbrake lever and the centralbrake rod. Full application of the handbrakelever (such that the lever is vertical) to thelast tooth of the ratchet compresses a steelspring inside the steel cylinder and energy isstored.The action of the brake lever imparts motionto the brake rod, the Bowden cable and theexpanding clutch. This mechanism forcesboth shoes into contact with the drum.At this stage, the brake unit is latent, themechanism waiting to see in which directionthe trailer will start to move.If the trailer starts to move backwards, thestored energy in the spring will be released.The trailing brake shoe and by reaction, theleading shoe together with the expandingclutch will tend to move in the direction ofrotation (reverse) and abut against the stop.Thus the trailer is braked.However, if the handbrake is NOT fullyapplied to the last tooth (i.e. vertical) and isset to some lesser position than the fullvertical, then problems will almost certainlyarise after the trailer has been uncoupledfrom the towing unit.If the trailer is parked on a reverse slope or ifit is pushed backwards, then the brakemechanism will act as though the trailer isbeing reversed by the towing unit. The shoesand expanding clutch will tend to move withthe direction of rotation (reverse) whichimparts pressure to the spring-loadedreverse lever, causing it to collapse. Thus,friction between the shoes and the drum isalmost elminated and the trailer will runaway.Operating the HandbrakeSome people may find it difficult to set thehandbrake lever to its full vertical positionwithout a great deal of physical effort.However, AL-KO have designed their systemso that the average user need not do so.For successful parking on a reverse slope orsteep hill, the operator need only apply thehandbrake with one hand while gently butpurposefully inching the caravan trailer asmall distance backwards with the other.The user must supply this small but essentialbackward movement to ensure that thefulcrum of the transmission lever moves pastthe point of reverse, thus preventing thelever from collapsing as it would normally dowhen reversing.Most users will find it easier to stand facingthe towing unit while applying the handbrake and at the same time gently push thecaravan an inch or two backwards with theirposterior.Gas Cylinder TypeA gas cylinder, acting as an accumulator ofstored energy, can be fitted to the handbrakelever to provide the same effect as a springcylinder.96