and seven locations long with a total of 21 wells to be pumped from
The modern push-and-pull power of iron is driven by an engine
or motor through a belt to a pulley on a countershaft to which is
attached a pinion meshing with a large gear wheel mounted on a
shaft having two crank arms. A pitman connects each crank arm
to a horizontal iron disk mounted on a vertical shaft and anchored
to a concrete foundation. The revolution of the pulley imparts a
reciprocating motion to the disks, which move in a horizontal plane,
and impart reciprocating motion to the. shackle lines. When the
number of wells to be pumped is small often only one disk is used,
and the second pitman and crank arm are not needed. Plate XIV
shows the plan and section of a modern power of this type, manu-
factured by one of the oil-well supply companies and commonly used.
A single-disk power of this type is generally run by a 25-horse-
power engine or motor and is designed to handle from twelve to
fifteen 1,600-foot wells, or eight to ten 2,500-foot wells, or a pro-
portionate number of deeper wells. A double-disk power is gen-
erally run by a 35-horsepower engine or motor and when properly
balanced will handle nearly twice the load of the single-disk power.
Efficient service from this type of power requires good founda-
tions and proper alignment, a balanced load, frequent lubrication,
proper condition of babbitt in boxes, and tight nuts, bolts, and keys.
The pulley on the countershaft should be of such a size that the
crankshaft will make 16 to 20 revolutions a minute, which imparts
the same number of strokes to the shackle lines.
Geared powers are of three general types: The spur gear and
crank-arm type, the bevel gear and disk type, and the bevel gear
and eccentric type.
SPUR GEAR AND CRANK-ARM TYPE.
The spur gear and crank-arm type consists of a horizontal counter-
shaft with drive pulley and a pinion that meshes with a spur gear
wheel mounted on a horizontal shaft having two crank arms, to each
of which several wells may be attached, by adjustable wrist-pin
connections, to give a range in length of stroke of 12 to 18 inches.
This arrangement is similar to the corresponding part of a push-
and-pull power; but it is generally built much lighter and is de-
signed to handle four or five wells less than 1,000 feet deep. With a
balanced load, a 10-horsepower engine will serve. Figure 10 shows
a plan and section of this type of power; a, b, c, and d are attach-
ments for shackle lines.
George, H. C. Surface Machinery and Methods for Oil-Well Pumping. Washington D.C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc12407/. Accessed July 14, 2014.