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www.grovegear.com

Quadro Accessories

Lecentric Helical-Aluminum

Lecentric Helical-Cast Iron

Technical Information

Mechanical

Warnings

and Cautions

Terms and Conditions

It is the responsibility of the original equipment manufacturer or user to install

and/or operate Ohio Gear Products in conformance with applicable local and

national safety codes, suitable guards for rotating shafts and couplings should

be used at all times. Good safety procedures should always be observed

whenever working with or around any transmission equipment. Fitness for

use is the customer’s decision and responsibility.

SERVICE FACTORS

– Numbers whichmodify the loads whichmust be considered in

selecting a speed reducer are called service factors. They vary with the type of service

in which the reducer is to be used, the kind of prime mover involved and the duty cycle.

WORM GEAR REDUCER SERVICE FACTORS

Proper determination of an application’s service factor characteristics is critical for

maximum reducer life and trouble free service. See the definition of service factor in

the glossary.

All Grove Gear reducers and Gear+Motors™ are sized for applications having an

AGMA defined service of 1.0, unless otherwise stated. (Alternately, 1.0 service

factor is sometimes expressed as “Class I Service”.) Reducers in such applications

operate on a continuous duty basis, for 10 hours per day or less, and are free of

recurrent shock loads. When operating characteristics are different than noted, the

input horsepower and torque ratings listed must be divided by the service factor

selected from the table below. This table applies to reducers with an electric or

hydraulic motor input.

SPECIAL APPLICATION CONSIDERATIONS

: Please contact Grove Gear for assistance in applications not

listed or for applications with unusual characteristics. Including the following:

• Input speeds not listed in catalog

• Frequent starting or repetitive shock applications

• Selection of reducers for man lifts or people moving equipment

• High energy loads, including stalling

WORM REDUCERS:

• Starting or momentary overloads exceeding 200% of gear reducer

mechanical capacity (100% overload)

SERVICE FACTOR TABLE

When a single or multi-cylinder engine is the input power, the service factor

selected from the table above should be increased by multiplying the value by the

factor selected from the table below.

Service Factor Conversion Table for Engine Driven Applications.

On page 418, AGMA standardized service factor data is listed for a wide variety

of applications operating 3 to 10 hours per day and for 10 hours or more per day.

BACK-DRIVING

– This is the converse of self-locking. Depending upon ratio and

many variables, it is difficult to predict the back-driving capability of a reducer. Worm

gear reducers are not intended to be used as speed increasers. Consult factory for

back-driving applications.

PEOPLE CONVEYING EQUIPMENT

– Selection of gear drives for applications

whose primary purpose is the transportation of people is not approved. This includes

such applications as freight or passenger elevators, escalators, man lift platforms,

and ski tows and ski lifts.

If the primary purpose of the application is material conveyance and occasionally

people are transported, the warranty may remain in effect provided the design and

load conditions are not exceeded and certification to the appropriate safety codes

and load conditions has been obtained by the system designer or end user from the

appropriate enforcement authorities.

STORED & INACTIVE GEAR DRIVE

– Each drive is protected with rust preventive

that will protect parts against rust for a period of 6 months in an indoor dry shelter.

If a drive is to be stored, or is inactive after installation beyond the above periods,

drain oil from housing and spray all internal parts with a rust preventive oil that

is soluble in lubricating oil and rotate the shafts several times by hand. Before

operating, drives which have been stored or inactive must be filled to the proper level.

Periodically inspect stored or inactive gear drives and spray or add rust inhibitor every

six months, or more often if necessary. Indoor dry storage is recommended.

EXCESSIVE OVERLOADS

– The maximum momentary or starting load must not

exceed 300% of rated load (200% overload). Rated load is defined as gear drive

rating with a service factor of 1.0. If the maximum starting or momentary load

exceeds the above conditions, compute a second equivalent power rating by dividing

the peak load by two. The gear drive selected must have capacity equal to, or in

excess of, the larger equivalent power rating.

REVERSING SERVICE

– Applications involving either more than 20 reversals per

ten hour period, or less than 20 reversals per ten hour period with peak torques

greater than 200% of normal load must be referred to Factory.

BRAKE EQUIPPED APPLICATIONS

– When a gear drive is equipped with a

“working” brake that is used to decelerate the motion of the system and the brake is

located between the prime mover and the gear drive, select the drive based on the

brake rating or highest equivalent power rating, whichever is greater. If the brake is

used for holding only and is applied after the motion of the system has come to rest,

the brake rating must be less than 200% of the catalog rating, refer the application

to Factory. Also refer to Factory all applications in which the brake is located on the

output shaft of the gear drive.

OVERSIZED PRIME MOVER

– Published service factors do not cover applications

that require oversize prime movers for high energy or peak loads. Refer such

applications to Factory for selection of suitable drives.

MAXIMUM INPUT SPEEDS FOR WORM GEAR REDUCERS

(GR, NH, EL SERIES)

Size 813 through 852 2500 RPM

Size 860 through 8100 1750 RPM

NOTE: Horsepower ratings for 1750 RPM should not be exceeded when operating

at higher input speeds. For higher input speeds, contact Factory.

APPLICATION CONSIDERATIONS:

Belt Conveyors – To determine the torque, establish the belt pull. In calculating this,

the effects of sliding friction and angle or inclination must be considered. The table

below shows application factors which may be sued in determining belt pull based

upon common combinations of materials and various angles.

Material Combinations

Angle from the Horizontal

0° 10° 20° 30° 40° 50° 60° 70° 80° 90°

Pivoting Bucket Conveyor 0.025 0.19 0.36 0.52 0.66 0.78 0.88 0.95 0.99 1.00

Belt on Rollers

0.025 0.19 0.36 0.52 0.66 0.78 0.88 0.95 0.99 1.00

Metal on Metal (Finished) 0.20 0.37 0.53 0.67 0.80 0.89 0.97 1.01 1.02 1.00

Fabric on Steel

0.27 0.44 0.60 0.74 0.85 0.94 1.00 1.03 1.03 1.00

Fabric on Wood

0.32 0.49 0.63 0.77 0.88 0.97 1.02 1.04 1.04 1.00

Leather on Wood

0.35 0.52 0.67 0.80 0.91 0.99 1.04 1.06 1.05 1.00

Wood on Wood

0.35 0.52 0.67 0.80 0.91 0.99 1.04 1.06 1.05 1.00

Plastic on Steel

0.35 0.52 0.67 0.80 0.91 0.99 1.04 1.06 1.05 1.00

Metal on Wood

0.40 0.57 0.72 0.85 0.95 1.02 1.07 1.08 1.05 1.00

Rubber on Wood

0.45 0.62 0.76 0.89 0.99 1.05 1.09 1.09 1.06 1.00

Rubber on Steel

0.50 0.67 0.81 0.93 1.03 1.09 1.12 1.11 1.07 1.00

Leather on Metal

0.56 0.72 0.87 0.98 1.06 1.12 1.14 1.13 1.08 1.00

The procedure involves selection of the proper application factor for the calculations:

Belt Pull = (Total Weight on Conveyor) x (Application Factor)

Torque = (Belt Pull) x (Radius of Head Pulley)

Example: An inclined belt conveyor is to move boxes of steel parts. The belt is fabric

on rollers. Five boxes will be on the conveyor at a time, and each weighs 50 pounds.

The conveyor is inclined at 10° to the horizontal, and the head pulley diameter is 7”.

How much torque is required at the head pulley?

Select .44 as the application factor.

Determine weight: 5 x 50 = 250 Lbs.

Determine belt pull: 250 x .44 = 110 Lbs.

Determine torque: 110 x 3.5 = 385 Lb. Ins.

HOISTS

– A worm gear is generally said to be self-locking or irreversible when the

gear cannot drive the worm. This static condition can be upset by vibrations from

nearby machinery or other sources. Many worm gear reducers are not self-locking,

and even a particular size and ratio, which may appear to be, cannot be depended

upon for this purpose. Also, a reducer which holds the load when upward movement

is stopped may not when the load inertia is moving downward and the motor is

stopped. For complete locking assurance, it is recommended that a fail-safe brake

be used for such an application.

CAUTION

Technical Information

Duration of Service

Uniform

Moderate

Heavy

Extreme

(Hours per day)

Load

Shock

Shock

Shock

Occasional 1/2 Hour

—*

—*

1.00

1.25

Less than 3 Hours

1.00

1.00

1.25

1.50

3 - 10 Hours

1.00

1.25

1.50

1.75

Over 10 Hours

1.25

1.50

1.75

2.00

* Unspecified service factors should be 1.00 or as agreed upon by the user and manufacturer.

Hydraulic or Electric

Single Cylinder

Multi-Cylinder

Motor

Engines

Engines

1.00

1.50

1.25

1.25

1.75

1.50

1.50

2.00

1.75

1.75

2.25

2.00

2.00

2.50

2.25

CAUTION