Cars Jumping rollers on conveyor

[DoubleEagle]

We see this happeninig when one of our customers puts the brakes on usually inside the wraps. When this happens they jump the rear roller and sometimes the extra roller. Question I have is this, on our busy days when we are pushing 80 cars / hour, it makes me abit jumpy when the cars are stacked so close (no room for error). On our busy days as when the lines get long we want to move the cars through without much wait. Is there any changes to rollers etc that can help avoid a possible collision inside the tunnel when this happens. We have the obvious signs and our attendents remind everyone entering (hands off wheel, car in neutral, foot off brake) but at least once aday we see this issue. It's only due to the diligence of our attendents or us looking at our cameras in the tunnel at that very moment and we see this and stop the conveyor before anything happens. Our roller spacing is 7'4" and conveyor speed is set at 138 cph. Also, I have been told we can go with 3'6" roller spacing and slow the conveyor down to achieve the same car per hour equivalents, I'm not convinced on this one. Any insite is appreciated.

 

[mmurra]

Seems like you are running the conveyor faster than necessary to get 80 cars/hr. Congratulations on having this problem (volume)!

 

[DoubleEagle]

cars jumping rollers

Yes we have seen some good days of late but have suffered like most through bad winters over the past two years. We bought our wash in June 2007 and then the recession hit along with the last two years of bad weather. With the 7 ft roller spacing and turning the speed down to 120 cph it seems like it takes forever to load cars. Do you think the increase in speed allows the cars to jump a roller when they brake on our conveyor? It only occurs when they brake. Many times we have to get inside the car and ride along with them.

 

[Earl Weiss]

Did an article a while back on this very topic. Usinfg easy average (but not exact #s) look at it this way. Average car + needed space = 30 feet. Chain speed a foot per second. This equals a possible production speed of 120CPH. You will do far less since things don't always work out perfectly, especialy with customers behind the wheel.

Now, for each imperfection you lose 7 feet = 7 seconds . Every 4 imperfections is 28 feet or about one car. If you are doing 80 cph it is easy to be imperfect have the time or 40 CPH which means the loss of 10 cars per hour. Cut that time, distance in have and you will lose 5 CPH. You will also have more safety rollers .

My rule of thumb has been when a place hits 100K a year, I went from 7 foot to 3'6" spacing.

 

[Earl Weiss]

Double Eagle.

What is your collection syystem like? A cashier at the conveyor entrance? Gates/ How many?

 

[DoubleEagle]

Cars jumping rollers

I have two cashiers who move the cars through very well, we have two attendents doing the prepping at the entrance, we only hit these numbers on the best days right after a good snow. Normally, we can handle the flow with one cashier and one prepping. We slow the conveyor down some on normal days. Our normal rate is about 50 cars an hour on a normal winter day and that is only during peak hours. We have seen an increase in volume over the past 6 months so we are trying to understand our peak patterns. They have changed drastically since last winter, weather has alot to do with that plus I think we are starting to see more loyality come our way. It has taken almost 3 years to bring the customers back that were lost by the prior ownership. It has been a steep hill to climb with the economy and weather patterns and were not out of the woods yet. Have not paid ourselves a dime in three years. All the profits (when we make any) goes right back into the business as improvements.

 

[Earl Weiss]

I have two cashiers who move the cars through very well, .

Please explain further.

Are both Cashiers working at the same time so that you have 2 lanes merging into one, or are these people on seperate shifts?

 

[DoubleEagle]

cars jumping conveyor

2 lanes merging into one, with a cashier servicing each lane.

 

[Earl Weiss]

2 lanes merging into one, with a cashier servicing each lane.

Well then it would seem your cashiers could process welll over 100 CPH (Demand warranting) . Assuming the tunnel can handle it you next need to weigh the cost of the extra rollers vis a vis profit, utility and safety. Witha 100ft conveyor (210' with turns) you need 30 extra rollers for 3.6" spacing. Depending on Equipment rollers run anywhere from $40.00 to $80.00 or more. That's $1200.00 - $2400.00 or more.

With 7 foot spacing you lose one roller and the next car is hopefully at least 7 feet back so no big deal. If you lose the second......

Now with 3'6"you can bring up two safety rollers in the same spacing. However, the Nimrods can still blow all three.

At stated volume 80 CPH you could expect perhps 5 CPH more over X hours. So 25 - 50?? cars per day. Don't know your pricing. $5 - $10.00 / car .

So, lets keep it simple again and figure an extra $100.00 extra net profit on a busy day plus extra security from nimrods and faster speed of delivery time appealing to customers. It would seem to be worth the investment.

 

[DoubleEagle]

cars jumping rollers

Earl thanks for the input, I am expecting to change the chain and rollers before next winter so thats what I am thinking of doing. I am not close to 100K a year in volume but I do believe this should help me move cars at a good pace and safely through the tunnel.

 

[sonicsoft]

How long is your conveyor?

Are you front wheel pull, or rear wheel push?

Do you have UHMW on the inside guide rail?

 

[DoubleEagle]

cars jumping rollers

132 ft conveyor, rear push. I am not familiar with UHMW. What does that stand for?

 

[Chiefs]

UHMW is a technical name for a very smooth plastic that should be attached to inside guide rail if you are rear wheel push and to the outside guide rail if you are front wheel pull.

We are front wheel pull (150') and when we installed our new conveyor 3 years ago, we found it necessary to put the plastic guide rial on both the inside and outside rails due to the groove in concrete on the passenger side of the tunnel which has developed over the last 50 years of car washing. It also ensures that no matter how the vehicle tracks that there is no metal to metal contact with these low profile and very expensive rims that people put on and also no friction of the wheel on any metal guide rail if the wheel rubs against either side to prevent roller jumping or worse.

The key to adding the UHMW guide rail is to inatall it with countersinking carriage bolts so nothing sticks out from the UHMW.

 

[Earl Weiss]

due to the groove in concrete on the passenger side of the tunnel which has developed over the last 50 years of car washing. .

We put down steel plates where the passenger tires track to solve this problem. Provides less rolling resistance.

 

[Ghetto Wash]

I am not familiar with UHMW. What does that stand for?

Ultra High Molecular Weight (polyethylene)

 

[DoubleEagle]

cars jumping rollers

yes we have that on the inner side of the conveyor. I am convinced all of our issues are customer related. Putting the brake on etc. The only time I see a different issue is with large 4 wheel drive vehicles and extended hummer or escalade type limos. We have to run them (limos) through on the front tire. So if they have oversize tires they want to walk over the inner rail of the conveyor. After having a hummer type limo go over our inner rail on the conveyor we now tell all limo drivers to hold the steeringwheel in the center while going through the wash. This has helped a great deal.

 

[Melvin01]

A right kind of conveying system is very essential in manufacturing units.I suggest you contact any experts who have a thorough knowledge about conveyors.Make sure that the conveyor is from a well known manufacturer.