Joyce BG450D - Manual (Page 5)

5
H. Wiper Seal (1)
I.
O-Ring (1, 2, or 3)
J. Shims (as needed)
K. Cover Gasket (1 or 2)
2-3 Sizing Bevel Gear Jacks - BG 450
When sizing a bevel gear jack consideration must be given to the relationship between the load,
travel speed, and duty cycle. Use the following procedure to determine the suitability of the BG 450
for your application. Use the steps below to calculate the load, travel speed, and duty cycle.
1. Determine the load in pounds.
2. Determine the velocity in feet per minute.
3. Determine the duty cycle in terms of minutes of operation (time on) and minutes resting (time
off).
4. Calculate PV = (load in pounds x velocity in feet per minute)/1000
5. Calculate T = (cooling time of 262 minutes x Time on)/Time off. Cooling time can be found in
Section 3-3.
6. Plot the point on the graph below for the calculated values. If the point falls below the line, the
application is satisfactory. If it is above the line, consider a double-lead lifting screw, or revise
the application to permit a value that falls below the plotted line.
7. Calculate the horsepower (HP) required:
a. RPM = velocity in feet per minute x 12 x input turns per 1” travel
b. HP = (Pinion Torque x Load x RPM) / 63,025
BG 450-S and BG 450-D Bevel Gear Jack
0
50
100
150
200
0 20 40 60 80 100 120 140 160 180 200 220
PV Values
T
V
a
lu
e
s
BG 450 S BG 450 D
Consider the following additional information:
8. Data is calculated based on limiting the lifting nut temperature rise from 70 degrees F to 200
degrees F.
9. One must compare the choice of a single-lead screw verses a double-lead screw.
10. If using the bevel gear jack as an integral miter gearbox. Contact an application engineer for
horsepower limitations.
11. Bevel gear jacks with a single lead, “S” are inherently self-locking, in the absence of vibration.
A brake is required on bevel gear jacks with double lead lifting screws, “D”.
12. Special jacks are available. Contact Joyce/Dayton with your design requirements.