Mk 5 Pan & Tilt Head Maintenance Manual
13
Fine adjustment screw
7
This is a leadscrew mounted in a pair of bearer blocks that are fixed to the underside of the platform,
each by four socket headed screws passing through the platform from the top face. The leadscrew is provided
with a knurled thumb nut that projects clear of the rear of the platform. A block with a steel spigot runs along
the thread of the screw; the spigot projects above the top face of the platform and engages with a recess in
the wedge adaptor plate
Locking plates
8
Two locking stays are fitted on the underside of the platform. Each stay is secured to a mounting block
by a shouldered bolt and locked by a hexagon nut. Each block is secured by two countersunk screws passing
through the platform from the top face. Each locking stay is retained in the folded position by a spring clip. The
locking stays match up with locking s
Tilt friction
9
This consists of a quadrant plate secured to the left side of platform (view from rear) by four
countersunk screws. The friction pads are fitted, one to a fixed block attached to the side guide bar, and the
other attached to the adjustable block. Friction is applied by turning the knurled thumb nut in a clockwise
direction. The friction pads are of leather and are attached to the block by adhesive and are pinned. The tilt
lock is similar to the tilt friction except that it is fitted to the right hand side and is operated by a simple ON/OFF
lever. The lock pads are of standard brake lining material.
Body assembly
10
The body assembly is a robust alloy casting providing the location for the side bar mechanism in the
integral arms, and the panning mechanism in the base. Each integral side member provides the recess in
which the bearing system is installed. These bearings support and position the side guide bars. Each bearing
system consists of two ballraces with fixed mountings and two ballraces on eccentric screws. One end of each
ballrace spigot is mounted in the side member of the casting whilst the other end is carried in the closing
plates. On the inner section of each integral side member location is provided for a cam roller, which consists
of a ballrace positioned on a shaft by spacers, the shaft being secured in place by a socket set screw.
Immediately below the cam roller a recess is provided for the side bar stop pin, this is held in place by a socket
set screw. The stop pin projects through the side arm and into a slot in the side guide bar, thus the limit of
travel is defined by the length of the slot. On the upper surface of the body casting are two small projections,
each of which carries a threaded stud with a knurled thumb nut the resultant action of which forms a clamping
device for the head locking plates. Finally a spirit level is mounted on the top face of the body, near to the pan
and tilt controls.
Base
11
The base is a machined cast alloy unit which provides the mounting face and pivot for the complete
assembly. The base takes the form of a thick circular disc with a deep flange on the upper surface and four
threaded holes on the underside, together with mounting bolt holes in the centre. Each mounting hole has a
3/8 in. BSW wire thread insert.
Panning
12
The base top face is fitted with a thin crush washer, a needle thrust cage and a housing washer. This
forms the bearing assembly on which the body turns. The base, together with the friction and lock assembly,
are fitted to the body by a special bolt passing from the bottom of the base through to the top side of the body.