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Shaft Locking Devices - TROMA-MACH sro

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<strong>Shaft</strong> <strong>Locking</strong> <strong>Devices</strong><br />

Other Considerations<br />

<strong>Shaft</strong> <strong>Locking</strong> <strong>Devices</strong><br />

• Minimum outer diameter of hub<br />

The hub must be of a size to withstand the pressure exerted by the <strong>Shaft</strong> <strong>Locking</strong> Device<br />

without yielding. Use the following equations to determine<br />

the minimum hub diameter (Dmin) required.<br />

Dmin = D "<br />

Yp + ( f × pH )<br />

Yp − ( f × pH )<br />

Where: D = Hub bore (inches)<br />

= Yield point of hub material (psi)<br />

Yp<br />

f = Form factor (see figure 1.)<br />

pH = Contact pressure on the hub (psi)<br />

f =0.6<br />

f =0.8<br />

• Combined torque and axial loads<br />

If an axial load is present, then the resulting torque that can be transmitted<br />

needs to be adjusted as follows:<br />

f =1<br />

Dh<br />

Dh<br />

Dh<br />

D<br />

D<br />

D<br />

Figure 1.<br />

Mt Result =<br />

Mt<br />

2<br />

⎛ F × d<br />

24 ⎟ ⎞<br />

+ ⎜<br />

⎝ ⎠<br />

2<br />

Where: d = shaft diameter (inches)<br />

Mt = maximum torque for device (ft-lbs)<br />

F = force (lbf)<br />

• Coefficients of friction and surface finish<br />

Lovejoy SLD uses µ = 0.12 which corresponds to a slightly oiled surface<br />

63 = 63 µIN RMS for surface finish<br />

• Duty factor<br />

The values Mt and F must be adjusted with a duty factor depending on the setup:<br />

Load<br />

Motor type<br />

Constant Light overloads Heavy overloads<br />

Electric<br />

1 1.5<br />

2<br />

Combustion<br />

1.5<br />

2<br />

2.5<br />

• Multiple <strong>Shaft</strong> <strong>Locking</strong> <strong>Devices</strong> used in series<br />

If more than one <strong>Shaft</strong> <strong>Locking</strong> Device is used, the transmissible torque<br />

must be reduced by the following factors:<br />

<strong>Shaft</strong> <strong>Locking</strong> Device<br />

SLD 1500<br />

SLD 1850<br />

SLD 1350<br />

SLD 2600<br />

Number of devices in series<br />

2 3 4<br />

.80 .75 .70<br />

.80 .75 .70<br />

.80<br />

.85<br />

.75 .70<br />

Not recommended<br />

www.lovejoySLD.com<br />

23

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