VẼ CƠ KHÍ Chapter 8 chain transmission

CHAIN JACK CHAIN DIMEMSION OF ROLLER CHAIN DISK HOW TO DRAW A ROLLER CHAIN DISK SPROCKET WHEEL AND CHAIN— Pitch radius is at the centre of the rivets, with a slight clearance for easy running LINK BELT AND PULLEY — A variety of hook link forms are in use for link belt trans­ mission CHINESE WINDLASS— The sheave and hook rises equal to one-half the difference in the circumference of the barrels for each turn of the crank See No 27 for the power.  CHINESE SHAFT DERRICK— The sheaves suspended from the upper part of the derrick legs allows the bucket to be raised above the mouth of the shaft or pit by the differential windlass ROPE TRANSMISSION from vertical to horizontal shaft, with tension slide and weight ROPE TRANSMISSION to a movable shaft at right angles from the driving-shaft, with tension slide and weight TOOTHED LINK CHAIN AND PULLEY , alternating double and single links STEP GEAR— A spur gear in which the face is divided into two or more sections, with the teeth of each section set forward a half or third of the pitch, according to the number of sections A ROLLER CHAIN JENSEN FF MK1 4WD TRAIN UNIT REMOVAL It is necessary to remove the gearbox/torque converter and chain unit as an assembly to gain access to the inside of the chain drive./The transmission is straightforward to remove but is very heavy Mechanical aids are required to deal with supporting the Weight, particularly during reassembly Remove the rear prop shaft by splitting the universal joint at the axle and pulling the shaft out of the transmission Disconnect the front drive shaft at the flange plate Couplings each end and remove the support bearing bracket and starter motor Access to the shaft and it's removal is much easier if the cross member running under the rear of the engine sump is removed Replace the crossmember after removing the shaft and use it to support the weight of the back of the engine using a block of wood as a spacer and load spreader under the sump.Release the gearshift and downshift cable linkages and Maxaret cables, then unbolt the bell housing from the engine and remove the rear crossmember/gearbox mounting The transmission assembly will move backwards and down clear of the car Ensure that the torque converter remains fully located in the bell housing during removal.If working in a pit and not using jacks, it will take four strong pairs of hands to handle the weight.Removing the chain unit from the differential and gearbox is covered in the works manual (Martin Robey can supply a good quality copy of the original works manual.) DISMANTLING Dismantling the chain unit is straightforward Some of the bolts holding the case together and the Maxaret bolts can only be turned with an open ended spanner as the heads are too close to the case to allow the use of a ring or socket spanner Before splitting the case, remove the bearing cap at the rear of the front wheel drive shaft preserving the shims under the cap The screws are secured with Loctite and are very difficult to release (Try an impact wrench) Under the cap is an outside circlip which retains the front drive shaft Remove the clip and drive the shaft forwards to remove it The shaft must be deflected away from the casing as it moves forward to allow it to pass projections on the case If the two halves of the case are difficult to separate, assemble two diagonally opposite bolts back into the case leaving them about 3/8" proud Then tap the heads gently with a hammer and the case will part    The driven chain sprockets will be loose in the case with the front drive shaft removed This allows the sprockets to be lifted out and the three chains removed There is a spacer between each sprocket Note also that the rear bearing for the front drive shaft is fitted with a flanged reducing bush in the centre If the bearing is to be replaced, press the bush out before discarding the old bearing If it is intended to replace the large bearings on the driving sprocket shaft, then the driving sprocket gear cluster will need to be removed from the rear casing This requires a special tool to release the locking ring which has four notches cut into the outside diameter There is a lock tab washer under the ring which is deformed into two of the notches Punch the locks flat first and then release the ring Again, the ring is secured with Loctite and is very difficult to release even with a tool If replacing bearings, the outer shells of the taper roller bearings are a tight fit in the casing If the shells get a bit damaged removing them it does not matter but to preserve the new ones in good condition try putting the shells in the deep freeze while the case goes in the fan oven at 100 degrees C for 10 minutes The shrinkage of the bearing shell and the expansion of the casing are such that, using gloves, the new shells literally drop in place and tighten as the temperatures equalise The reverse works well for fitting bearings to shafts i.e bearings in oven, shaft in freezer Don't be tempted to use a blow lamp to heat bearings and particularly casings The heat can be uneven and crack cases or destroy temper of bearings REASSEMBLY Reassembly is self evident and the reverse of the dismantling sequence I could not locate any gaskets for the casing so I made my own from 15 thou paper gasket sheet The seals and bearings are all available from bearing suppliers using the numbers in the list Note that taper roller bearings require two numbers, one inner and one outer, as the makers mix and match inners and outers I failed to locate a source of Morse chains so reused the original ones despite them being slightly stretched The Maxaret unit has a special thick cork gasket which I obtained from Cropredy Bridge Garage When refitting the torque converter to the gearbox check that the converter is fully home into the pump drive It can give the appearance of being in place but is in fact too far out on the shaft making it impossible to assemble to the engine To check, measure the distance between the front face of the bell casing and the top face of the bolt holes that secure the converter to the engine crank This must be at least 1/2".     The LinearChain is able to move loads horizontally and vertically The LinearChain is made of specially formed links, whose geometry prevents the chain from buckling under load This allows the LinearChain to work like a conventional linear actuator Benefits at a glance: Ideal for realizing long strokes, especially for applications where space is limited Compact storage, also in multi-axis applications Constant, shock-free motion Synchronous operation for horizontal or vertical motion