PENTAX
AUTOMATIC LEVEL
AL-6B
INSTRUCTION MANUAL
ASAHI PRECISION CO., LTD.
For proper operation of our surveying instruments
Our surveying instruments are so precise instruments that careful
handling is requested. The instruments neither work well nor
become of value unless they are properly handled or operated.
TO let instruments work effectively and be of use for long time, read
through this instruction manual carefully.
Storage
The instrument should be stored in a dry, dust proof room, which
does not have a big temperature range. When the instrument is
stored for a long time, it must be from time to time taken out of the
carrying case and exposed to the air. If the inside temperature of
storage place in a room or in a car were extremely different from
outside temperature, that is, measuring place, leave the instruments
exposed to the ambient temperature until temperature of it becomes
as close as to ambient temperature.
temperature.
The exposure time to the instrument will be about one minute per
one degree temperature difference.
Transport
For a long journey, by rail or road, the instrument should be packed
using enough cushicned materials to prevent any hard knock or
shock. If possible, it's recommendable that the expert should pack
the instrument for e. long journey. If you transfer the instrument by
your own car, it is not necessary to pack it but you had better leave it
on the seat and fix it.
In case it is put in the car trunk, wrap it well in blankets and so forth
and fix it by some method so as to prevent any hard knock or shock.
Checking
Before measurement, an instrument should be examined according
to this instruction book. If necessary the instrument should be
adjusted. Even a new instrument or completely repaired instrument
need to be checked. This procedure is also recommended during
long intervals of non-use or after tong jurney. At the end of field
season, It is recommendable the instrument should be checked by
repairman with a distributor.
Storing
When taking the instrument out from the case, please notice care-
fully and rernember how it is housed in the case so that re-storing
after use may be correctly and easily done.
Take the instrument out from the case with both hands.
Refer to page 11 storing item concerning other details.
Setting up
When installing or removing the instrument on or from the tripod
the instrument should be kept with one hand.
The instrument should never be left on tripod with the center screw
not being tightened.
Unless such step is taken, big accident would happen. Careful and
sensitive operation and handling of the instrument in accordance
with the instructions with plain common sense will surely provide
long and good service.
Contents
1. Equipment . ieee 4
2. Description ........ a 5
3. Technical Data ............. iin 6
4. Preparations for Measurement
4-1 Setting up the Instrument and the Tripod ............. 7
4-2 Levelling with the Circular level ...................... 8
5. Measurement
5-1 Focussing and sighting... ooo 9
5-2 Reading the staff .......................... 0. 9
5-3 Distanices ........... eee eee 10
5-4 Circle reading ...... 0000 er RRA 11
6. SLOMING ..... KK 11
7. Tripod . ea a a 0e 0 12
8. Tests and Adjustments
8-1 Tripod .... ia 13
8-2 Circular level .......... ee 13
8-3 Automatic compensator . 2.2 e 11142000 14
8-3 Horizontal collimation ............ 222.000.000 15
1. Equipment
Instrument
Objective cap
Adjusting pin
Ptumb bob
Plastic carrying case
— | — — md
Fig. 1 Equipment
* A plumb bob and adjusting pins are stored in
the hole immediately under the instrument.
2. Description
Gun sight
collimator
Reflecting
Mirror
Objective---—— Circular
lens level
—————— (Circle rotation
ring
Me Horizontal Drive
y Base plate
3. Technical Data
| Telescope
| Magnification 20%
Effective aperture (mmy/in) 30mm/1.2in
Field of view at 100m/100ft 2.6m/2.6ft
Shortest focussing distance 0.7m |
Resolving power 4” |
Multiplication constant 100 |
| Additive constant 0
Circle
Graduation 1°0r 1g
Reading 1 orig
Estimation reading 6' or 10c
Automatic compensator
| Range +12"
Sensitivities of circular level
a Per 2mm 10
Setting accuracy |
Automatic compensator +0.5
| Standard deviation _
1 km double run leveling 5 2.5mm
Dimensions a
Instrument 193x139 x 126mm
Case 250 170 190mm
Weight
| Instrument 1.1kg/2.41b
Case | 0.8kg/1.81b
4. Preparations for Measurement
4-1 Setting up the instrument and the tripod
Adjust the tripod to the height suitable for observation when the
instrument is mounted, and set it up on the ground. For angle mea-
surement, set the tripod on the ground point using the plumb bob,
and firmly dig the legs into the ground. Set the instrument on the
tripod head and secure it tightening the center screw. (For measur-
ing angles, lightly tighten the center screw and properly shift the
instrument on the tripod head so that the tip of plumb bob may
coincide with the ground point.)
EM NT CDE SE
Instrurnent
®. —— Tripod head
Leg screw
Fig. 4
4-2 Leveling with the circular level
Set the telescope in parallel to the line connecting two optionally
selected leveling screws, and turn them to position the bubble of the
circular level right at the center.
The bubble travels in the same direction that your left thumb moves
to turn the leveling screws. With the bubble positioned at the center,
turn the other leveling screw to bring the bubble into the center of
the circle.
Before any survey work, be sure to turn the telescope 180° in the
opposite direction to check that the bubble remains in the center of
the circle. Also check that the automatic compensator operates
properly, in accordance with Chapter 8-3. If the bubble is out of the
circle center, “The adjustment of circular level” is needed.
(See page 13).
Telescope Leveling screw Bubble Setting circle (A) (B) Fig. 5 Cir-
cular level
Fig. 5
5. Measurement
5-1 Focusing and sighting
Aiming the telescope at the light, rotate the eyepiece counter-
clockwise to draw out the eyepiece ring. While looking into the
eyepiece, rotate it clockwise until the corss hair of the reticle
becomes first clearly visible.
It is advisable to relax when looking into the eyepiece. An intense
look at the reticle may tend to cause parallax or eye fatigue,
Then, aim the telescope at the target, looking through sighting
points. Rotate the focusing knob so that the target becomes clearly
visible.
Gun sight
collimator
Fig. 6 Fig. 7 Reticle Supplied
5-2 Reading the staff
Reading of the staff should be done at the center of the cross hair on
the reticle. For a reading example, refer to ..... Fig. 8
2.185m
Fig. 8 Reading example
q —
5.3 Distances
Distance from the instrument to the staff can be measured by the
stadia hairs charted on the reticle. Read the graduation interval on
the staff put between the upper and lower stadia hairs and multiply
the value by 100 to measure the distance.
Stadia hairs
Fig. 9
===" A1 (195.4em)
A? (173.8cm)
. os Fig. 10
This is formulated as follows: (A1 — A2) x 100 — S
wherein, 5— distance
A1= reading the upper stadia hair
A2= reading the lower stadia hair
Example: A1 = 195.4 cm A1 — A2 = 21.6 cm
A2 = 173.8 cm ____ x100 —
S — 21,6 M
5-4 Circle reading
Equipped with a horizontal circle, AL-6 is capable of horizontal angle
measurement or setting. Graduation reading is of the index reading
type. This provides direct reading of 1° or Ig. The unit of 1/10 of the
graduation i.e. 0.1° or 0.1g can be read in estimation.
{See Fig. 11)
z “CTE TE
(A) 8430 (3607) (В) 94.59 (4004)
Fig. 11 Metal circle
6. Storing the Instrument.
Take off the accessories, if attached, before dismounting the instru-
ment from the tripod.
Put the cap back on the objective lens. Wipe the instrument clean
Using a soft cloth. Carefully wipe the instrument, if damp or wet,
with a soft cloth to dry it completely before storage into the case.
Never store the instrument into the case unless dried up, since
moisture will affect it adversely. Neatly secure the accessories into
their original positions in the case so that they never move inside.
Store the instrument into the case while gently dropping it in posi-
tion with the Pentax mark on the body facing towards you.
If the case cover does not close smoothly, the instrument is housed
improperly, and store it again correctly with reference to the photo.
Fig. 12
7. Tripod TS-3
Measurement results are greatly affected by the quality of a tripod.
Pentax genuine tripod features high stability and reliability ensuring
satisfactory measurement results.
Fig. 14
8. Tests and Adjustments
8-1 Tripod
The each connection parts of the tripod should be firmly secured.
Using a screwdriver or wrench, be sure to tighten each screws com-
peletly.
8-2 Circular level
For adjustment of the bubble on the level being off-center in the
circle as described in Chapter 4-2, follow the procedure below:
(1) Turn the leveling screw to bring the bubble to the center.
(2) Turn the instrument 180° check that the bubble remains at
the center, if not, half of the bubble run should be corrected
by rotating leveling screw, and another half of the bubble
run should be corrected by turning the adjusting screws by
means of the adjusting pin.
(3) Turn the instrument 180° again, check that the bubble re-
mains at the center. If not, repeat the adjustment procedure
from the start until the bubble stays at the center of the circle
when the instrument is rotated in any direction.
Adjustment screw
Adjustment screws
Fig. 15
Setting circle Bubble
Circular level
Fig. 16
8-3 Automatic compensator
After the correct setup of the instrument as in Chapter 4-2 and
circular level adjustment as in Chapter 8-2, check the automatic
compensator.
With the instrument set so that the objective lens is positioned
above an optionally selected leveling screw, sight the staff or an
appropriate target.
Sighting the staff or the target, lightly rotate the leveling screw just
below the telescope. At this time, the staff or the target sways verti-
cally within the telescope.
It is proper functioning that when it comes to a standstill, the sight-
ing position should be returned to the initially sighted position.
If, however, not returned to the first sighted position or the staff
simply moves vertically without swaying in accordance with the
leveling screw, they are all improperly functioning and adjustment
or repair is needed. In this case, contact a dealer.
8-4 Horizontal collimation
Checks
1. Prepare two identical target plates and set up the instrument in
the middle between two walls at a distance of 50 to 100 meters.
(Fig. 18)
2. Sighting both walls alternately, adjust the target plates to the
height so that readings on the target plates are identical, and
secure them in position.
3. Shift the instrument to a position approx. 2 meters from one
target plate and level it for readouts of both targets. If, in this
case, reading of both targets is identical, no adjustment is
required. If not, adjust as follows:
Target About 2m
|
(А) (В)
Fig. 18 Horizontal collimation
Adjustments
(1) Sight the farthest target plate through the telescope.
(2) Remove the eyepiece cover, rotate the reticle adjusting screw
using the adjusting pin and adjust the reading to be identical to
that of the closest target.
(3) After checking that correct adjustment has been made, mount
the eyepiece cover back in place.
Reticle
adjustment
SCrews
Fig. 19
— 16 —
MEMO
— V7 -
PENTAX
ASAHI PRECISION CO., LTD.
Miyakezaka Bldg., 1-11-1 Nagata-cho,
Chiyoda-ku, Tokyo 100 Japan
Printed in Japan
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