Bulletin Technical News Cham, December 1994 Conveyor Drive with Shaft-Mounted Helical-Bevel Gear Unit 1. Introduction The current trend toward using larger IS machines with higher production capabilities necessitates longer machine conveyors. To maintain an acceptable level of drive power, a drive unit improvement involving higher performance gearing was implemented. 2. Description Conventional conveyor drives for toothed chain (Westinghouse belt) and wire mesh belt (with magnetic pulley) for IS machines are equipped with a worm wheel reduction gear (ratio 60:1 / 30:1). However, worm wheel gear efficiency is characteristically low. Significantly improved performance can be attained through the use of bevel/spur gears, which have much higher operating efficiency. 3. Application 3.1 Previous Status Previously, the following worm gear boxes were used: Gear reduction / Part Number Conveyor Drive for : Conveyor Assembly 60:1 30:1 Toothed chain 117-E-8015 59-55136 59-55138 Wire mesh belt 191-D-7494 59-46507 59-55139 1
3.2 New status: The new gear unit (part no. 59-55143) is now used with the following drive units: Gear reduction / Part Number Conveyor Drive for: Conveyor Assembly 30:1 (precisely: 29.41..:1) Toothed chain 117-C-8100, Gr 3 59-55143 Wire mesh belt 117-C-8100, Gr 4 59-55143 Bevel gear unit 59-55143 replaces all four different worm gear box types to permit greater standardization. Additional ratios are obtained through the use of pulleys and belts. However, the gear unit has an uneven gear ratio of 29.41927..:1. The EFRA-C program of the RPD drive control has an integrated correction factor to compensate for this uneven ratio. The new program version V4.0 (July 94) supersedes V3.5 (July 1993) and permits gear type entry by means of the HHT. 4. Specifications 4.1 Scope The EFRA-C program has a bevel gear correction factor of 0.981 for correcting the uneven ratio (29.41927...:1) of the new bevel gear. The remaining error of 0.036 % is within tolerance specifications with respect to synchronization with other equipment and for proper conveyor operation. 4.2 HHT Display In the software version display, press the NEXT key for the Menu Bevel Gear Type. As in version 3.5, the HHT automatically reverts to the software version display if a key is not pressed within approx. 15 seconds. To remain consistent with the other parameter screens, the first line indicates theactivesettingatthetoprightandanewsettingcanbeenteredatthe bottom right of the second line. 2
Fig. 1 below shows the display when a worm gear is selected; Fig. 2 indicates when a bevel gear is in operation for the conveyor. Entering a 0" or a 1" at the cursor s position (the blank underline in the Figs.) followed by DO will instruct the EFRA-C to swap the active setting. BELT GEAR TYPE:0 BEVEL=1 WORM=0 _ BELT GEAR TYPE:1 BEVEL=1 WORM=0 _ Fig. 1 Fig. 2 4.3 Belt Motor RPM Display The numeric value displayed for the calculated conveyor drive motor speed is also affected by the gear type setting. Accumulated errors arising in case of a bevel gear can cause a 2 rpm error in the RPM Display. 4.4 Default Parameter Worm Gear is the default parameter for the belt gear type. The EFRA-C is supplied with this default setting, and the unit will default to Worm Gear in the event of a memory malfunction. 4.5 Instruction Labels All EFRA-C units with program version 4.0 have an instruction label on the cassette with instructions for correct entry of the gear type with the HHT. This labelmustbeadheredtothecassettewhenupdatingtheprogramversion. 5. New Equipment Refer to drawing 191-C-24380, sheet 3, for the new drive, pulley and belt configuration. (Pulleys and belts Type : 1/2" pitch, 1" width). 3
5.1 Conveyor Drive Unit for Toothed Chain : Refer to drawing 117-C-8100, Gr. 3 for toothed chain operation (Westinghouse belt). Fig. 3 5.2 Conveyor Drive Unit for Wire Mesh Belt : Refer to drawing 117-C-8100, Gr. 4 for wire mesh belt operation (with magnetic pulley). Fig. 4 4
5.3 Procedure for non-efra C drive controls Conveyors with a toothed chain type belt exhibit a slight disadvantage in that they run slightly faster after having been in operation for some time. Most conventional drive controls can compensate for this error through the use of a belt trim feature. This same feature can also be used to compensate for the uneven gear ratio. The belt speed correction factor is calculated as 0.981 times the standard belt speed. This must be performed manually at the drive control. 5