EDON is continually looking for ways to improve our Conveyor Line Tracker family based on on-going design analysis and customer feed back.  Recently, we have introduced several new features which are now standard for our heavy-duty family of Line Trackers, which improve performance and/or provide easier maintenance and repair.  These features are available after 1/1/06 on all new units and can also be retrofitted to existing units.  If retrofitting is contemplated one needs to consider the labor cost involved to update the Line Tracker, especially if it is at premium time.  It may be more economical to replace the Line Tracker with the new style incorporating these new features.

ROLLOUT FRAME

On many installations it is necessary to remove the complete Line Tracker, along with its mounting frame, for repair or service.  Reinstallation necessitates that the Line Tracker be realigned and in some cases recalibrated.  This task is somewhat tedious and can be time consuming, especially if the EDON unit is installed in a hard-to-reach area.  The rollout frame feature allows the unit to be quickly removed from the conveyor and replaced.  Simply by removing the four (4) Allen screws which hold the rear cross bar of the Line Tracker frame and unplugging the encoder, the unit can be quickly rolled out of the frame on the four (4) supporting cam followers.  This does not disturb the frame alignment to the conveyor and it enables one to perform all service on the bench versus struggling to perform the repair on line.  On some applications when automation is involved (robotic or other types of automation) and where the conveyor is tracked on a pulse per unit of conveyor travel basis, the Line Tracker may still need to be recalibrated after the unit is services or reinstalled. Since service is so mush easier and quicker with the rollout frame, we have seen more timely service from maintenance personnel.  Pulling the entire unit on older Line Tracker was always viewed as a nasty and risky job.  In some cases it may actually deter maintenance.

RUB RAIL GAUGE BAR

A very critical clearance and one that is generally over looked, but one that can have serious consequences relative to conveyor tracking accuracy, is the clearance of the EDON dog chain to the conveyor links.  We specify clearance of 1/8".  On some conveyors, especially floor conveyors, it may be difficult to gain access to view the clearance and consequently it is difficult to adjust.  If the EDON Line Tracker is jammed into the conveyor chain, registration of the dog chain is random to the conveyor and not gauged from the edge of the conveyor link.  Thus, tracking accuracy drifts and tracking errors occur and can accumulate.  The gauge bar is incorporated into the dog chain rub rail and assures the proper dog chain to conveyor spacing.  We find that most accuracy issues with Line Trackers are related to improper installation and/or clearances of the dog chain to the conveyor chain.  The gauge bar eliminates these problems. (back to top)

ANTI-JAM DOG CHAIN

The EDON dog chain has always had a square dog.  On systems where the conveyor exhibits slack in the conveyor chain, or where the EDON unit is not properly adjusted to assure dog engagement near the center of the conveyor link height, dog engagement can create jamming and consequently tracking inaccuracy.  The anti-jam dogs are CNC machined and incorporate generous radii on the entry edges to assure smooth engagement into the conveyor; thus, providing more uniform encoder pulse counts which relate directly to tracking accuracy.  EDON recommends that dog chains be replaced every 18 to 24 months (see “Automatic Tensioners” below). (back to top)

AUTOMATIC CHAIN TENSIONERS

We recommend routine tensioning of the dog chains and chain replacement at least every 18 to 24 months to assure tracking accuracy and smooth performance.  Because of poor access to the Line Tracker in many installations and/or just plain lack of maintenance, chain tension is seldom maintained.  Or, if the chain is manually tensioned it is typically over tightened and then it is too long resulting in encoder pulses being added at every dog entry; thus, creating tracking inaccuracies which are exhibited by the part being behind the control point.  Generally, if there is a problem due to dog chain tension it is usually a failure that results in downtime costs far exceeding the cost of a new chain or even a complete new EDON unit.

The heavy-duty Line Tracker has always had a manual tensioner on it.  One of the reasons we always utilized the manual tensioner was that it permitted the Line Tracker to be universally installed as either a right or left hand drive.  Whereas, with the auto-tensioner, the Line Tracker must be specified when ordering as either right or left hand.  This isn’t that big of an issue; however, it does cause some loss of flexibility with the hand specific unit since we need to know the hand prior to fabrication.

Recently, on several heavy-duty models we have added automatic dog chain tensioners as standard.  Our experience from monitoring the tracking accuracy of units with and without auto tensioners shows greatly enhanced performance in encoder pulse count uniformity and conveyor tracking accuracy with the automatic tensioners.  The auto tensioner retrofit is easy to install and requires drilling one (1) hole for the spring retainer block. (back to top)

HIGH PERFORMANCE TUNE-UP KIT for Standard and Heavy-Duty Parasitic Line Trackers...

We have assembled a High-Performance Tune-Up kit for our Standard and Heavy-Duty Line Trackers. This kit includes all of the wear items which should be changed out every 12 to 18 months for maximum performance.  The kit includes (depending on the model):

·         Anti-jam dog chain

·         Automatic chain tension arms

·         All sprockets including bearings or bushings (model dependant)

·         Clutches and line shafts for A-11420, A-11396, and A-10788 models

Refer to the "Spare Parts Price Guide" in the Support/Downloads section for High Performance Kit Pricing. (back to top)

AIR MOTOR

Encoder drives and Line-Trackers generally incorporate gearing to achieve a desired conveyor tracking resolution.  With any system involving gearing, backlash between the gears can be a problem if it is excessive or if it is too tight.  On most systems this is not an issue.  However, on some systems there may be a need for a higher degree  of accuracy and excessive slop in the system can be a problem.  For those applications we provide anti-backlash control.  It is accomplished via rotary air motor.  The air motor's function is to maintain a drag on the rotary output shaft of the Line Tracker.  In effect it maintains dog contact between the Line Tracker drive chain dogs and the conveyor and also controls the backlash between the Line Tracker's main drive gears.  The constant drag on the system not only controls slop, but also smoothes out the overall performance of the Line Tracker which is reflected in the uniformity of the encoder pulse counts.  Generally this feature is only incorporated into the Linear Line Trackers (A-11420, A-11396, A-10788) when a high degree of tracking accuracy is required. 

The air motor also serves another purpose on the linear units.  Since the Linear Line Tracker incorporates clutched drives they only operate in one direction.  In other words, the linear units do not count in the reverse direction should the conveyor back up.  The counter-rotation of the air motor enables the Linear Line Trackers to count in both the forward and reverse directions.  (back to top)

SEALED BALL BEARING U-JOINTS

Edon now offers precision, pre-lubed and sealed, needle bearing construction U-joints for use with our Linear Line Trackers and encoder drives.  Refer to part number MUJ-66 when ordering.  (back to top)