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TENSIONING & IDLING SYSTEMS

Correct operating tension is an important factor in the satisfactory performance and life of any v-belt or chain drive. As v-belts wear they seat themselves deeper in the sheave grooves. This seating, along with belt stretch lessens the initial tension. The result is slippage and loss in horsepower capacity unless some form of take-up is used to restore and maintain the original tension.

As chains wear they elongate, which results in sway, slap and increased vibration. This puts undue shock into the drive and increases bearing wear. As the chain elongates, it “crawls” out of the sprocket teeth and results in dramatic premature sprocket failure and decreased drive life.

Both v-belt and chain drives wear at an increased rate if they are allowed to run with insufficient tension. Adjustable center distances are the recommended method of maintaining proper tension. In cases of fixed center distances, tensioners and idlers provide the necessary means of take-up. These tensioners and idlers provide a means of obtaining extra belt or chain wrap frequently needed for high ratios, multiple shafts or serpentine drives.

 

“Traditional” tensioning or idling devised face the following problems:

 

1.         Too much tension in a drive causes excessive belt, chain and bearing wear.

2.         Too little tension in a drive allows belt slippage or chain vibration, resulting in loss of power and additional wear.

3.         All traditional idlers should be installed on the slack side of the drive.

4.         Traditional v-belt idlers should be used on the inside of the belt, which results in a corresponding horsepower loss due to the reduced arc of contract.

5.         Idlers used on the outside of a drive should be located approximately 1/3 of the center distance from the small sheave, pulley or sprocket, or the drive will suffer detrimental effects.

6.         Chain wrap or pulley wrap must be 120 degrees of the small sprocket or sheave in order to have adequate drive life and in order not to suffer horsepower loss.

7.         Traditional idling sprockets add increased wear to the drive.

8.         The system must be mounted, maintained and lubricated.

 

SnapIdle® A patented concept that induces minimal wear to the chain drive since the chain rides on the side plates.

Snapidle_® (Chain Tensioners)

Snapidle_®’s patented concept induces minimal wear to the chain drive since the chain rides on the side plates. (U.S. Patent No:4,662,862 - 4,798,562. Foreign Patents Pending)

 

Snapidle_® provides a constant amount of tension to the chain drive, increasing drive life. It tensions, guides, quiets, controls and increases both chain and sprocket life. It requires no mounting devices or maintenance and is a benefit to the drive system, not a deterrent. Economical, easy to install, maintenance free, the Snapidle_® is the answer to the problem of controlling drive chains.

By being able to take up tension through the chain, Snapidle_® eliminates the need for adjustable center distance drives. All chains may be ordered in even pitches (eliminating half links) since the additional tension may be taken up by the Snapidle_®.

Since the Snapidle_® “floats” on the chain drive and actually absorbs shock, it does not add to vibration in the drive. Both sprockets will have the maximum chain wrap possible, thereby increasing chain life (load sharing) and sprocket life (the chain is unable to crawl out of the teeth).

On large chain drives, the expense required to install a tensiong system may be unrealistic. A Snapidle_® unit at a fraction of the cost of traditional tensioning methods can tension almost any roller chain drive. Many multiple strand drives cannot be tensioned by traditional idling or tensiong systems, but are readily fitted with Snapidle_® economically.

 

Hi-Temp Snapidle_®

For temperature applications ranging from 200 degrees Fahrenheit to 450 degrees Fahrenheit, the SI-HT series should be considered. With all the benefits of the standard Snapidle_®, it offers the enhanced benefit of controlling drive chains in extreme temperatures. Where most tensioning systems are not applicable, Hi-Temp Snapidle_® solves the problem.

Extra-Heavy Snapidle_®

In extreme environments, there is the SI-XH series. Dry, dusty and gritty environments (where the chain is usually not lubricated) require a product that can take the punishment. Recommended for the harshest environments and for high speed chain applications, the SI-XH is tougher than the environment.

Self Lubricating Snapidle_®

The SI-SL series is recommended where chain lubrication is a problem. The SL Snapidle_®’s top block contains up to 40% oil… lubricates while tensioning your chain.

 

Single Guide Snapidle_®

Where space is at a premium, especially on serpentine drives, the SI-SG series is easily installed and adjustable. An economical way to adjust tension and control drive systems where the standard Snapidle_® is not applicable.

 

SELECTION CONSTRAINTS

VELOCITY LIMITS

Oil bath:                    Chain speeds should not exceed 2,500 F.P.M.

Standard lube:          Chain speeds should not exceed 1,800 F.P.M.

Bone dry:                  Chain speeds should not exceed 800 F.P.M.

 

ENVIRONMENT

 

Temperature:          Maximum operating range of any standard Snapidle_® unit is two hundred degrees F. For temperatures above two hundred degrees F. use the SI-HT Series Snapidle_®. (Not to exceed 450° F.)

 

Chemicals:               Metal carriers are stainless steel. Screws and pins are zinc plated carbon steel. Wingnuts are die cast zinc. Bolts are zinc plated carbon steel with nylon inserts. All stainless steel (300,304) construction is available upon request.

 

Environment:          In extreme environment (i.e. abrasive grinder dust, foundries, gypsum facilities, dry glass, etc.) especially in a lack of lubrication situation, the wear on the carrier will be greatly enhanced. In the case where the standard Snapidle_® does not provide adequate life, the SI-XH Snapidle_® series should be used.

 

Reversing Drives and Orientation: The Snapidle_® series has no limitation on the direction of rotation. The Snapidle_® may be used in any chain drive attitude.

 

MISALIGNMENT

The Snapidle_® series can tolerate any misalignment compatible with a roller chain drive and, in most applications, will allow a roller chain drive to operate with a larger misalignment. Misalignments in which the plane of one sprocket is rotated relative to the plane of the second or in which the plane of one sprocket is moved laterally relative to the other sprocket, or a combination of the two, can be tolerated.

 

SPECIAL APPLICATIONS

For drives not listed in the cross-reference charts, for non-listed chemical applications or for further engineering information: please supple the following information: