Poweramp CM SERIES MECHANICAL 12.2006 - Manual (Page 19)

OPERATION
17 4111-0006 — July 2006
Theory
The CM-series mechanical dock leveler uses large lift
springs (U) to apply force to lift arm (T). The lift arm
pushes against the underside of the platform (C),
rolling on the cam (not pictured) forcing the platform
to rise. The force of the spring tension is just enough
to lift the weight of the platform. The ratchet pawl disengages only when the platform
release ring (F) is pulled AND held. Spring tension
from pawl spring (J) causes the ratchet pawl to
engage the ratchet bar when the release ring is let
go.
When the platform rises to approximately 2 – 3 inches
(51 – 76 mm) from its full raised height, the lip spring
(P) and a chain pulls the lip link (D) forward. This, in
conjunction with the lip assist spring (E), causes the
lip linkage to push the lip out and up. The lip assist
spring also helps control the amount of time required
for the lip to fully fold.
To lower the platform, the operator walks out onto the
platform. The platform will lower until the extended lip
rests on the truck bed. If the lip did not fully extend or
there is no truck at the dock, the platform will lower
until one of the following conditions occur:
• Lip is resting on lip keepers (cross-traffic position).
• Lip did not fully fold causing the platform to rest on
safety legs (below-dock position).
• Lip did not fully fold and safety legs are retracted,
causing the platform to rest on the safety stops (full
below-dock position).
The hold-down ratchet assembly will keep the
platform at the desired position until the platform
release ring is pulled again.
To actuate the dock leveler platform, the operator
pulls and holds the platform release ring (F) located
in the recess at the rear of the platform. This causes
ratchet pawl (G) to disengage from ratchet bar (H).
With the ratchet pawl disengaged, spring tension
from lift springs (U) forces the platform to rise.
NOTE: Ratchet pawl (G) and bar (H) are part of the
hold-down mechanism (M)
A — Lip
B — Lip Maintenance Prop
C — Platform
D — Lip Link
E — Lip Assist Spring F — Platform Release Ring
G— Ratchet Pawl
H — Ratchet Bar
J — Pawl Spring
K — Main Frame
L — Platform Maintenance Prop
M— Hold-Down Mechanism
N — Safety Leg (2 used)
P — Lip Spring Q — Shock Absorber
R — Safety Leg Linkage
S — Safety Leg Retract Pull Ring
T — Lift Arm
U — Lift Springs
IMPORTANT IMPORTANT
When activating the leveler, always pull AND hold
the platform release ring until the platform is at the
full raised position. Releasing the ring while the
platform is still rising may result in damage to the
equipment.
A
E
C
B
F
D
U
T
S
Q R
N
M
G
H
J
P
K
L