Monthly Archives: May 2012

Q&A Session – Question 4: Whats wrong with after-market parts and solutions for my Telebelt?

Nothing, as long as they don’t affect the over-all performance of the machine or threaten other more expensive components. Take a look at the photo to the right of a drive pulley cover on a TB105 for example; it is strong and strongly mounted, so strong in fact that it has been responsible for stalling belts for the lucky and wrecking belts for the un-lucky! The intended and designed reason for a cover in this area is just to keep the hose bundle away from the drive pulley. The original solution was just a piece of steel tube bolted across the center and later ended being a piece of UHMW (plastic). The advantage of the plastic is that in the case of a rock or other object getting caught between the belt and the cover, the hundred dollar cover looses not the more expensive main belt. You can finish the day’s placing without the pulley cover but not without the belt! After loosing a main belt, ask your self how much does that cover cost and how nice does it look?

The last photo is of some of the items we at the Putzmeister Repair and Service Center have run across or removed while doing repairs. A single ply belt has never been factory installed on a production TB model of any kind. Why? Because they do not work! Obviously a customer bought what the belt guy was selling. We have never found a method of patching a belt that had any longevity. Any belt patch is a “stop gap” measure at best and neither one of these two even make that grade! Belt strength is rated in pounds per inch of width (P.I.W.). If you cut the belt all the way through the fabric anywhere you have reduced the P.I.W. of the belt. If you cut a big six inch “V” out of the eighteen inch belt, as in the lower sample, you have reduced the belts strength by at least a third. We are not even going to mention that the cut and the patch are within the profile of the scraper! Not only is the scraper blade in the photo just a piece of steel that is not even straight, it is also too long!

In closing, Putzmeister America understands. We know especially considering todays economic times, that rising costs and harder to find work make everyday maintenance and parts replacement a real concern for making ends meet. In an effort to show our understanding and keep us and our customer’s competitive, Putzmeister America’s Customer Support Group has just recently reduced Telebelt parts across the entire line by 15%! In addition, the competitive rates and flexible schedule of our Midwest Repair and Service Center further help you get quality parts with quality, experienced installation. So, next time you need repairs or parts on your Telebelt, please consider the “real” cost of what you are having installed. Both our reputations depend on the quality of those parts.

Q&A Session – Question 3: Why use Putzmeister rollers in my Telebelt?

Using the right rollers in the correct position is very important to the life of the belts and the over-all performance of the Telebelt. Once again, the location and design of our rollers are a product of years of experience and practical application. Building a “cheaper” roller is not always in the best interest of practical application.
This can be the case if roller design and fabrication cost savings end up producing a design that threatens the integrity and longevity of more costly components, such as belts. This can also be the case if new approach or design just does not perform as well. As an example, our hopper roller design prevents the belt from being “pulled” down between the roller and into the U-shank brackets when tensioning the belt (see images above and below).


Our roller caps are a simple and re-useable design that has worked rather well over many years. People have tried to substitute these caps with other designs without the same level of success, resulting in one-time-use and often missing roller caps (see left and below).

Q&A Session- Question 2: I am constantly approached by people selling belt, why should I use Putzmeister belting?

ANSWER:

Putzmeister belts have a long track record and proven history of performance. The material specifications and splice procedures are intended for concrete conveyors and the Telebelt application. These details have evolutionized over many years of trail, research, testing, design, and actual use and application. Other belts made with other materials have been tried and tested over those years, and none of the alternatives have ever measured up in longevity. The splice design and methods have changed many times over the years, and Putzmeister has updated the splice design as recently as a couple of years ago.

We have had long-time loyal customers try “bargain” priced belt and most or all of them have come back to using Putzmeister belting and splicing. We have tried everything from urethane belts to “poly” and “poly-blend” fabric belts. We have experimented with “cold splices” and countless variations of splice prep and have always come back to the vulcanized, step and bias splice presently used because of longevity as related to application.

Those of you that have also tried alternative belts and splice methods may have heard that our pulleys are too small. Our chosen belt and splice design takes in to account the size of the pulleys and the fact that we have an aggressive and effective scraper. The splice design reduces that amount of splice area that is going around a pulley or across the scraper. It is a good “rule of thumb” to remember when talking to a belt salesman that that is exactly what he is, a belt salesman. We are an equipment manufacturer that builds machines that use belts, and therefore have a vested interest in how that belt performs in our machine. Our reputation and that of our product depend on it! Some old time worn clichés may apply when shopping for belting;

  1. If it sounds too good to be true it probably is.
  2. Sometimes you do get what you pay for.
  3. And…..Buyer beware.

We realize that technology does change and our industry is no different. We are alert and open minded to product improvement if and when changing technology offers it. However, until any “better mouse-trap” has a field track record that can compare remotely to the forty years plus of design, testing and field application of our present belting and splice design and methods, we humbly recommend that our customers go with a known commodity when considering replacement belts for their Telebelt.

Q&A Session- Question 1: Why are there 16″ scraper blades on an 18″ belt?

ANSWER:

Telebelts are equipped with “crowned” pulleys. Slightly tapered pulleys allow for easier adjustment when training or tracking of the belt. This is especially true on faster moving belts such as those used to place concrete. This feature is even more important for the purposes of belt training when the conveyor is telescopic, multi-section as is the Telebelt. Trust me, flat pulleys were tried in the very early design and training the belt throughout the telescope range was impossible! Even when only half the pulleys were flat it was still an impossible task to track the belt.

When a tensioned belt wraps around a tapered pulley it leaves that pulley with its edges opposite the pulley taper. That is to say the belt comes off the pulley in a crescent shape, with edges of the belt somewhat lower than the center (see diagram 1, left). For this reason, using a scraper as wide as the belt wears out the edges of the belt pre-maturely.

Getting proper surface tension between the blade and the belt also becomes more difficult because the force being used to pull the scraper against the belt has to deflect the edge of the belt that much more before adding any appreciable force in the middle or center (once again see diagram 1). This problem becomes worse the further behind the pulley the scraper is mounted. This is because you now have to deflect the tensioned belt in both directions, width and length, before significantly effecting the tension of the blade against the surface of the belt (see diagram 2, below, – upper right-hand corner).

You may have read in some of our past literature words like belt “flutter” and scraper “bounce”. These are also symptoms of the scraper being too far behind the pulley. A mistimed or an unlucky scraper bounce can catch a rock and render the scraper useless, or worse wreck a belt! A “fluttering” belt will not run clean. In all cases, an 18” blade on an 18” belt makes every condition or symptom worse!

When you hear customers saying things like; “I just can’t get that thing to run clean no matter how much I tension the scraper!” or “My scraper springs are stretching and I have run out of adjustment on the scraper chains or T-handles!”, the main two causes are scraper blades that are too wide and scrapers that are too far behind the pulley.

Besides these problems, you have to ask why do you want to clean the belt out that wide anyway? The tunnels, even on a machine set up for high volume placing, will only expose a max of 12” or 14” of belt, and most are set up with only about 9” to 11” of belt exposed. The material leaves these transfer skirts on a “V” shaped belt and the material profile on the belt doesn’t reach to those outside edges of the belt. If the concrete is so liquid that the material profile within that the normal “V” shape or in the discharge transition area reaches the edges of the belt, more than likely the belt is running too slow or there is too much belt exposed between the skirts or both. The bottom-line is that on a machine that is properly set up and run, there is nothing out on the last inch of belt on both sides to clean!

The only historical leg to stand on in defense of same width blades and belts is that the earliest Telebelt model I mentioned earlier ran 16” blades with a 16” belt. There are couple reasons for this. Firstly, that machine ran 4” pulleys and they just were not as aggressively tapered, lessening the severity of the systems described above. Second, and the most reality based reason, is that the manufacture just never got around to making a 14” scraper blade (assigning a whole new part number, etc). Every other concrete conveyor built used the ‘2” narrower than belt width scraper blade’, up to and past 48” belts. So, the only machine that ever used same width scrapers did so because the manufacture just never got around to making a 14” blade with some of its components allowing it to get away with that oversight. That doesn’t make it correct!

Setting Telebelt Feeder Lift Pressure Switches

Function:  When the main conveyors are slewed, the brakes on both the feeder and the main release.  If this happens with the feeder off the ground, the feeder will:
a) swing behind the main conveyor like a real long counterweight, or
b) take off downhill if the machine is not level.

The feeders are raised hydraulically, but they lower by gravity as the oil passes through an orifice.  The feeders must be fully lowered for the mains to slew.  It looks like you are “powering down,” but you’re just letting the cylinder and rails relax.

If there is enough pressure in the feeder elevate circuit, the (NC) pressure switches open and break the connection to the slewing valve.  The WBV valve still goes to the “boom” side.  One switch disables slew right and the other disables left, and they are both connected to the feeder lift line through a manifold block.  No oil flows to release the brakes when the slewing valve doesn’t throw.

Symptoms:  Main will not slew left, but slew right works, or vice-versa.  It’s very rare for the main to not slew in either direction because of pressure switch adjustment, but it can happen if there is enough pressure on the system.  All functions work manually.  Cable remote makes no difference.

 “Field Fix” (to complete a pour):

  1. Make sure the feeder is down fully.  All pressure must be off the feeder elevate cylinder.
  2. After confirming feeder is firmly on the ground, try manual control.  Make sure to move the WBV (selector valve) andthe slewing valve.  If it still doesn’t slew, the problem is not the pressure switch.  If the main does slew, options are:
    1. Operate slewing manually to finish the pour.  Keep the feeder firmly on the ground while slewing the main.
    2. Bypass the pressure switches by:
      1. Removing the plug connector from the top of one the switches.  On a 110, it might be necessary to remove the fan shroud to do this.  If the problem is unchanged, that is the correct plug.  If it now won’t swing either way, replace that plug and remove the other one.
      2. Put a jumper wire between pin 1 and pin 2 of the plug.  A piece of tie wire will do.  Do not reconnect the plug, but tie it out of the way to keep it from shorting.
    3. Alternate bypass – Jump X10-17 to X10-18 for right or X10-19 to X10-20 for left.
    4. This is a temporary fix and permanent repairs MUST be made before taking the unit out again. 

     

    Procedure for Setting Telebelt Feeder Lift Pressure Switches

    NOTE: THIS PROCEDURE CAN ONLY BE PERFORMED WHEN THE SWITCH IS INSTALLED IN THE CIRCUIT. THESE ILLUSTRATIONS ARE MERELY FOR SHOWING THE SWITCH.

    The feeder lift pressure switches are installed to prevent the main boom from slewing when the feeder is off the ground.  This is a safety system.  The switches are installed in the feeder elevate hydraulic circuit.

    To set the switches, you need a continuity tester, 1/8” Allen wrench and a flat-head screwdriver.

    Procedure:

      1. Support machine with outriggers.
      2. Unstow the feeder from the rest on top of the main boom and slew feeder to side of machine.
      3. Lower empty feeder (NO HOPPER OR ATTACHEMENTS) until the feeder legs are 1 to 2 feet off the ground.
      4. Turn off the remote.  The truck engine can also be shut off.
      5. Remove wire connection plugs from both switches.
      6. Remove small brass screw adapters from both switches.  These are the adapters that the plugs screw in to. 

      1. Connect a continuity tester to terminal #1 and #2 (terminals are labeled on switch and plug)

      1. With 1/8” Allen wrench, turn the pressure adjustment screw in, (screws are located under the brass screw plug you removed), until you get continuity, then back screw out until you loose continuity.  From this point, back the adjustment screw out ½ turn more, this is your final setting.

    1. Repeat steps 8 on the other switch.
    2. Reinstall the brass screw adapters and wire connection plugs.
    3. Restart the engine, reset the remote and test the settings by lowering the feeder to the ground, then lift main boom out of the boom rest and slew main boom to the right and the left.  The main boom should slew.  Then raise the feeder off the ground and slew main boom right and left.  The main boom should not move.

Telebelt Receiver Fuses

The e-stop circuit of Telebelts includes the HBC 735 radio receiver.  Actually, the e-stop circuit supplies power to the radio receiver. 

The images below, A370160 Pg 4 and Pg 5 show the circuit. To view at a larger size, click on each photo individually and they will open in a new window.

The 12V supply (red) goes through the e-stop stations to X81 pin 13.  X-81 is located on the right-hand (hinge side) of the control cabinet.  The power then goes through a fuse in the radio receiver and returns to X81 pin 5, and then through the e-stop stations to 4A17, the e-stop relay. 

 

 

 

This image shows the pin locations on X81.

 

 

 

 

 

 

The image shows the inside of the 735 radio receiver.  There are 4 fuses called out in the image, and their reference numbers correspond to the reference numbers in the image that follows.

 

They are:

42 = Power supply primary – 6.3A

43 = Power supply secondary – 1.0A

44 = Proportional output card – 12.5A

45 = E-Stop card – 4A

 

 

All of these fuses remove by pushing the end cap in slightly and rotating it to the left.  When the cap releases, a spring pushes it out a little.  The fuse will be attached to the cap.  You might need a coin or flat blade screwdriver to remove the cap.

 

RULE #1 – The problem is NOT in the radio system

 

Symptoms of a problem:  

 

E-stop will not reset and there are no LED’s lit on the receiver.

 

FUSE FAILURES IN THE RECEIVER ARE RARE.  Make sure you check all the way through the e-stop circuit (SEE RULE #1).  A blown 4F17 or a bad e-stop button causes the same symptoms.

 

If you have no power at pin X81-13, the problem is NOT in the receiver.  If you have 12V at X81-13 and zero volts at X81-5, check fuses 42 and 43 in the receiver.  Either one of these fuses, when blown, cause these symptoms.

 

Before replacing any fuses and turning power back on, find the short.  Likely places are faulty e-stop buttons or their boxes, or cable shorts between X81 and the radio receiver.  The 90’ cable can be substituted for troubleshooting purposes.

 

E-stop will not reset and there are LED’s lit on the receiver.

 

SEE RULE #1.  There are many possibilities, including:

  • Remote switch problem.  Verify with cable remote
  • See control box schematic:
    • Blown 3F64
    • 4K69 or 3K275 bad or unseated – confirm by flashing 4A17-T33 to 4A17-T-34
    • 4A17 connections bad
    • 4A17 defective
  • Problem with receiver cable from X81 – use 90’ cable to confirm

 

If all else doesn’t correct the problem, check 4A fuse #45 on the e-stop card.  If the receiver cover is off, you will see the “light show,” but attempts to reset will just cause relays on the card to click.

 

E-stop will reset and there are LED’s lit on the receiver.  Only non-proportional functions (toggle switches) work, but moving joysticks only cause the WBV (Boom/Outrigger) selector valve to move.  The actual function levers do not move.

 

RULE #1 might not apply.  This is opposite from when the pilot valve relay is bad, or when you turn on the transmitter but don’t reset.  In that case, the function levers move but the WBV valve does not.   Just to be sure, use the cable remote to confirm the radio problem, then check the 12.5A fuse #44 on the proportional output card.

 

Before replacing any fuses and turning power back on, find the short.  Likely places are faulty cables or plug connectors on MBC valve, or cable shorts between X81 and the radio receiver.  The 90’ cable can be substituted for troubleshooting purposes.

Telebelt – Hose Bundle Wrap


FOR ALL “ACTIVE” FEEDERS: 130, 110, 80 and 600.

 

CAUTION:

Feeder hose bundle is short.  This means it is already wrapped once around the feeder ring.  When the operator goes to set up, he may tear the bundle off if he swings the feeder the wrong direction.  The hoses need to be “unwound” by raising the transfer and rotating the feeder.
NOTE-

The feeder is bi-directional.  You must watch the hose bundle to assure you are pushing it back out and not wrapping more inside.  You might have to pull on the loop, if it has bound up and doesn’t move freely.

 

The hose loop should nearly touch the deck when in travel position.