TRANSMISSION ASSEMBLY
Note: numbers given during procedures refer to components illustrated on either Figures 5.1 or 5.2. Refer to Chapter 11 Transmission using these Item Numbers to Obtain the assosiated Part number
5.1 TRANSMISSION REMOVAL
* Using the manual transmission switch, allow the transmission to travel to the lowest position and then switch off the machine.
* Remove the left-handed-screw spherical-nut (45) from the top of the spider ( See Figure 5.1 ) and then lift off spider complete with paper carriers.
* Put the spider assembly (with the carriers facing downwards) in a safe position; where the assembly cannot cause injury to you or others.
* Remove all the liquid from the tanks as explained under: CHAPTER SIX CHEMICAL CHANGE.
* See Chemical Tank Assembly. Remove the splash guard, chemical tanks, heater band, probe and thermometer.
* Lift and turn the PVC. outside splash-tube (42) clockwise to disengage it from the drive flange fixing pins. Push it to the
bottom of the index tube.
* Loosen the lockin g screw, which secures the drive flange, (44) using a 5/32 inch allen key. The drive flange will spring up and come to rest. You may now remove the drive flange from the transmission shaft.
* Now lift and remove the outside splash-tube.
* Using a 3/32 inch allen key, loosen the two locking screws (79) in the bumper collar (40) and lift off the bumper spring assembly (61).
* The white chemical tray assembly should now be carefully removed.
* The electrical wiring to the transmission induction motor can now be disconnected.
* Now release and remove the three large hexagonal locking nuts which secure the metal transmission support ring.
* Lift the transmission support ring – with the transmission attached – so that the assembly comes out over the mounting bracket, (Sometimes referred to as goal posts), You may find it easier to lower the right hand bolt first, and remove the transmission unit from the studio. You will also find it useful to rotate the transmission as you lift it out.
* If necessary the transmission assembly can be removed from the support ring by releasing the nuts and bolts. These are situated one at either side and one at the rear.
5.2 TRANSMISSION INSTALLATION
* If necessary attach the transmission assembly to the support ring by bolting it on with two bolts and nuts at the front of the unit and one bolt at the rear.
* Install the transmission support ring – with the transmission attached.
Do this by rotating the transmission so that the motor moves under the mounting bracket from above and the assembly lowers onto the three support bolts and on top of the spacers.
* Re-position the right hand bolt – if necessary – to the original position and then tighten the locking nut.
* Twist the three hexagonal locking nuts and washers down loosely and close-to the support ring.
Now place the small chemical inner tray over the transmission shaft.
* Connect the induction motor electrical wiring the connectors together, so that the wiring lead, neutral and ground matches.
* Replace the white chemical tray.
* Place the inside tube (bumper-spring assembly) over the transmission shaft with the locking collar at the bottom.
Position the locking collar approximately 6″ (15 cm) above the chemical tray and lock it by tightening the screws with a 3/32 allen key.
* Now place the PVC outside splash tube over the inside tube with the bayonet slots located at the top.
* Fit the drive flange loosely onto the transmission drive collar, with the flange resting onto the circlip – spider locating pin to the top. Tighten the drive flange using a 5/16 allen key.
* Raise the outside tube and twist into position on the drive flange dowels.
5.3. HEIGHT AND CENTER ALIGNMENT
*Using the manual transmission switch, run the transmission until the spherical nut is about to enter the ball-guide-bush. Stop the transmission at this point by switching off the manual transmission switch.
* Switch off the mains switch.
* Continue raising the transmission slowly by turning the large pulley anti -clockwise by hand until the spherical nut is about to enter (or the height and centre gauge touches) the ball guide bushing.
* Avoid collision of the spherical nut with the ball-guide-bushing as this could cause damage to the transmission index shaft.
* To centre the spherical nut in the ball-guide-bushing, loosen, reset and re-tighten the hexagonal nuts mounted each side and at the rear of the transmission support ring.
* The hexagon nuts are for adjustment of both height, and alignment, of the spherical nut and ball-guide-bushing, and one adjustment affects another.
NOTE: This procedure take s time and you should take great care, to check and re-check, until the transmission is correctly aligned.
* Rotate the large pulley by hand in an anti -clockwise direction until the spherical nut just enters the ball guide bushing. Turn the fitted spider assembly so that the trigger turn-in pin is approximately in the centre of one of the holes at the end of the spider arm castings. Temporarily tighten up the drive flange fixing screw.
Raise the transmission further by hand until it reaches the top of its stroke. Now set the gap between the underside of the trigger body and the top of the paper carrier cam. This gap should be between 1 mm and 1.5 mm.
Alternatively, if you are using the height and centre gauge, the correct height is where the inner line is level with the outer sleeve.
NOTE:
a) Never turn the transmission pulley clockwise as this may cause the machanism to jam.
b) The point od vertical aligment is where the spherical nut on the transmission shaft meets the ball-guide-bushing.
c)The ball-guide-bushing is mounted under the camera shelf. When correctly aligned, the spherical nut at the top of the transmission shaft enters and releases freely from guide bushing in all positions.
d)The object of thesecomponents is to provide a lock for the tranmission when the film is being fed into, or withdrawn from, the paper carriers.
* Check for backlash to ensure that the two components do not touch when the trigger reverses. (See paragraph 5. 7 )
NOTE: If you are replacing the existing spider, there is no need to chack the trigger gap as t comes into place automatically. However. if you are using a spider that har not been on a machine previously, you must set the trigger gap as described in paragraph 8.1.
5.4 TRANSMISSION STRIP DOWN
* The most common faults which cause problems with transmission units are paper carriers jamming or misalignment of paper carriers and/or spider as these will make the gear shaft twist out of alignment. It is very important therefore that you align the paper carrier correctly. (See ADJUSTMENTS CHAPTER EIGHT)
* In the transmission unit itself, major faults occur with time. The main two are:
1) The Keys in the Cross Shaft breaking off. (This is indicated by the Transmission not turning in sequence).
2) The Cam Follower falling apart after many years of work. (This is indicated by the fact that there is only a slight bounce at the bottom stroke).
* It is, therefore, necessary to be able to strip down the transmission and Re-condition it.
REMOVAL (Refer to Figure 5.2)
* Remove the transmission from the studio by switching on the machine and lowering the transmission to its bottom position.
* Switch off the machine and remove the spider assembly from the transmission.
* Lift off the chemical tank tray.
* Mark across the drive collar (43) and the drive flange (44) with two lines to fix the position for re-assembly and remove the drive flange, this is fastened with one socket head screw. Lift off the outside tube (42), loosen the two socket screws holding the bumper spring collar and lift off the collar, bumper spring and inside tube.
* Disconnect the wires to the transmission motor.
* Remove the three nuts which hold the transmission ring to the transmission supports.
* On the right hand front bolt, loosen the nut which locks the bolt to the support, and lower this one bolt down, level with the top of the support. This is necessary to allow you to remove the transmission.
* Lift the transmission off the remaining two bolts and pull the transmission pole towards you, rotate the transmission and transmission ring over the front support and lift out of the Studio.
* Remove the transmission ring from the transmission by removing the two nuts and bolts from the front of the ring and the single bolt from the rear of the ring.
* Place the transmission on a bench, if it is possible to hold the transmission in a vice or some other locking device it is better, but if that is not possible then allow the transmission to rest back against its motor.
5.5 REMOVING THE TRANSMISSION COVER
* This is the most delicate part of dismantling the transmission; and if the instructions are not followed carefully, it is possible to damage the thread in the end of the cross shaft, on which all the gears run.
* You will require the set of allen keys, and the transmission key, which should be part of fotoautomat minimal tool kit.
* In the centre of the transmission lid is a ring of metal (18) flange-adjusting held by four hexagon headed screws, in the centre of this flange is a socket pressure plug (19), remove this plug.
* On the side of the flange are two more socket screws (but much smaller), loosen these screws but do not remove them because under these screws are two lead plugs which may be lost if the screws are removed.
* In the centre of the flange there is the retainer-adjusting (17) and this has a centre hole and four more holes, surrounding the centrehole. These holes are for the transmission key. This retainer will rise out of the flange adjusting bout 8 to 10 mm and then it will stop. Do not attempt to continue unscrewing the retainer, it is locked under the flange.
* In the centre of the retainer is another socket screw, this screw goes down through the retainer and into the cross-shaft.
* The cross-shaft must be released from the ball bearing which is in the flange assembly before the cover can be lifted off. It is not possible to lift out the socket head screw to expose the shaft, so unscrew the socket screw 2 or 3 threads then insert a punch, (or a thin metal rod), in the socket head screw and tap it down with a hammer. As you tap the screw down you will feel the cross-shaft being driven out of the ball bearing. Loosen the socket screw again and tap down again, continue until you feel or hear the cross-shaft fall into the case.
* Around the edge of the lid are the hexagon headed screws which bolt the lid to the case, remove all these screws.
* Tap the sides of the lid with a leather or plastic hammer to loosen the lid.
* The lid is held by two positioning pins and the Idler shaft (6).
* Insert a wedge under the lid and progressively loosen the lid around its circumference. Lift off the lid.
* The transmission case contains approximately 0.5 litres of oil (1 Imperial pint). Because of the angle of the transmission as it rests against its motor, this oil will not flow out over the edge of the open case. If however you would prefer to drain this oil you can remove the drain plug in the bottom of the case or tilt the case and allow the oil to flow into an appropriate container.
* In front of you in the open case you will see a series of gears one beneath the other on the cross shaft, and to the right of the cross-shaft the idler shaft with its idler gear (9) and spacer (10). Remove the spacer. Support the rack (36) and remove the idler gear, lower the rack to the bottom of its stroke.
* The top wheel on the cross-shaft is the index disc assembly (13), this is held on the cross-shaft by a woodruff key (20), lift off the index disc. If this proves difficult then use a gear puller.
* Once the index disc is out the woodruff key is exposed in the shaft. Take care that this does not drop into the case.
* Remove the woodruff key. If this key is tight in the shaft, tap the end of the keydown with a punch and a hammer until it rises from its slot. These keys should slide fit and should never be hammered into the slot. If it is ever necessary to fit a new one then it must be filed down to fit the slot. A good fitting key should rock up and down in its semi-circular slot, but with no side ways movement.
* The second gear on the shaft is the cluster gear assembly (5) and this is held in place by an external circlip. Remove the circlip, with a pair of external circlip pliers.
* These are a standard tool and can be purchased at most tool shops.
* Lift off the cluster gear.
* The third gear is pivoted on the Idler shaft and is the sector gear (7). This is held in place by the tension spring (60).
* Remove the tension spring and lift the sector gear from its shaft.
* The last gear is the worm gear (3). This is held to the cross shaft by a second woodruff key. It is not normally necessary to remove the worm wheel and cam assembly from the shaft and the whole assembly can be removed by grasping the cross-shaft and lifting the whole assembly out.
The transmission case now only contains the worm shaft assembly (28) and the index tube and rack (33, 36), it is not normally necessary to remove these parts as they very rarely develop faults. However, should these components need replacing, proceed in the following manner
* To remove the index tube and rack, remove the large external circlip at the top of the rack (57) and remove the three screws (71). Holding the guide tube assembly, lift off the guide tube assembly and pull out the rack with the shaft and the splined block.
* Remove the large circlip holding the index tube assembly and lift it out of the collar holding it to the casting. This will result in an oil spill.
If you must remove the worm shaft, first remove the pulley ensuring that the worm shaft has not been damaged or bent by the retaining screw in the pulley.
* Remove the four 10:32 Hexagonal bolts from the worm shaft cap and withdraw the worm shaft assembly.
5.6 TRANSMISSION UNIT ASSEMBLY
* The worm shaft assembly and rack and index tube assembly are replaced by reversing the dismantling order.
* The worm wheel and cam assembly, the sector gear and cluster gear can be re-assembled in the same way. Once these assemblies are in, it is necessary to set the height of the rack; this is vitally important and must be correct. If the rack is too high the splined block will jam against the Idler gear. If the rack is too low the circlip on the top of the rack will hit the guide tube.
Please follow this procedure exactly:
Plug the transmission motor into a 110 V supply with an on/off switch.
* Switch on the motor and the worm wheel; sector gear and cluster gear will rotate. Watch the rotation and note that the sector gear moves up and down as the cam follower follows the cam on the worm wheel. Stop the transmission when the cam follower is running along the top of the cam, See Diagram of ”Cam Assembly”.
* Raise the rack assembly until the splined block rises out of the index tube.
* Drop the idler gear onto the idler shaft between the cluster gear and the teeth on the rack.
* Measure the distance between the top of the guide tube and the underside of the large circlip. On the drive collar the measurement should be 30,7 cm to 31,2 cm depending on wear factors in the unit.
* If the rack is too high then remove the idler gear, Re-check the measurement, or raise the rack if the rack is too low.
* Switch on the transmission and check that the splined block does not touch the idler gear and the circlip does not hit the top of the
guide tube.
* Replace the idler spacer.
* Make sure the circlip is on the cross-shaft holding down the cluster gear and then insert the woodruff key in the slotin the cross shaft.
* Re-fit the index disc onto the cross-shaft and over the woodruff key, check that the woodruff key has not been pushed out of its slot.
5.6.1 Re-fitting the lid
* Check that the gasket between the lid and the case is not broken or the oil may leak out at that point.
* Pour 0.5 litres of oil into the case (multi-grade car oil is acceptable). Do not allow any oil to go into the tapped hole in the end of the cross-shaft, if you do and you fit the screw, the oil under pressure will break the shaft.
* Lower the lid onto the locating pins and the idler shaft.
* Fit an allen key into the socket head screw in the centre of the retainer and screw the screw, one or two threads into the cross-shaft.
* Fit two bolts through the lid into the case.
* Fit the transmission spanner and screw the retainer down two or three turns.
* Refit the allen key to the socket head screw and screw up the screw, this will pull the cross-shaft up into the ball bearing in the lid.
* Fit all the other lid bolts.
Turn the transmission by hand using the pulley and check that it is moving freely. Then switch on the motor and allow the transmission to run through its perating cycle. It should rise to the top of its stroke, pause, drop 1″ (25 mm) turn to the left, (clockwise), drop to the bottom of its stroke bounce 6 times then begin the cycle again.
5.7 BACKLASH
* To set backlash in the gears. Run the transmission up to the top of its stroke and switch off. Fit the drive flange to the drive collar.
* The backlash is the amount of sideways movement in the shaft at the top of its stroke. If there is too much, the paper carriers will move from side to side when they are under the feed down unit and the film will not go into the paper carriers. If there is not enough the transmission may seize up.
* Grasp the drive flange and twist it from side to side, there should be a small amount of movement, because the retainer has not been fully screwed down.
* Fit the transmission key and slowly screw down the retainer. At the same time continue to move the drive flange from side to side, testing and feeling for the movement. When almost all the movement is out stop turning the transmission key.
* Do not overtighten and then attempt to unscrew the retainer, as it will not loosen the backlash.
* As you have been tightening down the retainer the index disc has been pushed down the cross-shaft and cannot be pulled up again.
* when the backlash is set, re-fit the pressure plug and tighten in the two socket screws in the side of the adjusting flange. Now re-fit the transmission to the machine, re-assemble the inside tube, bumper spring and collar, outside tube and the drive flange.
* Re-align on the two marks between it and the drive collar.
* Replace the tank tray and spider.
* Connect the motor wires to the main hamess and set the transmission unit in the correct positions for height and centre. See ”Height and Centre Alignment under 5.3”
* Check all paper carriers by running film into them, and out of them, through the Delivery Unit.
* Ensure the transmission stops on the Trigger microswitch when all the paper carriers are closed.