Dental Vega Chair
Filling Oil Reservoir
Wipe or blow any dust or foreign matter from the reservoir. DO NOT WIPE WITH ANY PAPER OR CLOTH LIKELY TO LEAVE LINT ON THE CAST SURFACE. Lint accumulation can cause malfunction of hydraulic system.
Place the chair base in the desired location and pour the two cans of Ritter Hydraulic Oil into the reservoir.
Use no more than 2 U.S. quarts of oil. Use Ritter
Hydraulic Oil only-it is especially selected to fulfill the requirements
of the hydraulic system.
Attaching Lift Assembly to Base
NOTE: To carry lift assembly, grasp the guide roller
casting at the two places where it overhangs the lift assembly body. Do
not rest weight of lift assembly on oil intake beneath Power Unit.
With a lint-free cloth, clean off the top surface of
the oil reservoir casting; then apply a uniform coat (about 1/32"
thick} of the Permatex Form-A-Gasket No.2 (supplied} to the area shown in
Figure 7. Keep the Permatex coating thin enough and far enough from the
edge to prevent oozing into the oil reservoir when the lift assembly
mounting screws are tightened down.
Position the lift assembly with the solenoid valves
in the relationship to the rotation lock *shown in Figure 5, carefully
lower it onto the base platform assembly with mounting holes aligned and
secure with the four 3/8”-16 x 1 1/2" long, hex head machine screws
(Figure 8} supplied. The screws can be more easily assembled if all are
started before any are tightened.
* If the Chair has a gliding base and is for left-handed operation, release the rotation lock and swivel the reservoir 180 degrees to relocate the rotation lock as shown in Figure 5 before mounting the lift assembly.
EXPELLING ENTRAPPED AIR FROM LIFT SYSTEM
filling the reservoir and attaching the lift Assembly and wires, it is
necessary to expel all air from the lifting system.
2. Touch an insulated jumper wire to the terminals for black and orange wires (shown in Figure 5) to connect the terminals. (This will start the motor).
3. After the motor has run for about 10 seconds, keep the motor running, and tighten and loosen the vent screw 3 or 4 times in rapid succession. (Each time the tubes will start to rise and will stop when the screw is loosened).
NOTE If the tubes should rise to the point where the screwdriver will not reach the vent screw, touch the jumper wire to the black and white terminals on the small 10 terminal block (Figure 5), and push the tubes down with your foot; then proceed:
ATTACHING SEAT FRAME TO CHAIR BASE
By means of the
jumper wire mentioned above, raise the elevating tubes about four to six inches.
This is done to prevent possible damage to the base components. Position the
seat frame on the Chair Base so the back of the Chair Top is above the solenoid
valves; then secure the centerpiece to the inner elevating tube with the four
hex head screws provided. (See "A" in Figure 6).
NOTE Make certain
the overflow tube ("8" in Figure 6) enters the hole in the centerpiece
AND SWITCH WIRE CONNECTIONS -CHAIR TOP TO BASE
IMPORTANT After the Hydraulic line is connected; air must be expelled from the tilting system as described nexted.
See Figure 7. Connect the wires of the shorter "control switch
cord" to the horizontal 6 terminal connection block and the wires of
the longer "accessory switch cord" to the vertical 10 terminal
block illustrated. Refer carefully to the wiring diagram in- side the rear
base cover, noting that the wires of the longer "accessory switch
cord” which have black and white insulation connect to terminals having
brown and yellow wires respectively. Connections to the 6 terminal block
are strictly according to insulation color code.
See Figure 7. Connect the wires of the shorter "control switch cord" to the horizontal 6 terminal connection block and the wires of the longer "accessory switch cord" to the vertical 10 terminal block illustrated. Refer carefully to the wiring diagram in- side the rear base cover, noting that the wires of the longer "accessory switch cord” which have black and white insulation connect to terminals having brown and yellow wires respectively. Connections to the 6 terminal block are strictly according to insulation color code.
Expelling Entrapped Air from Tilting System
Operate the "Back" and "Forward” buttons- to tilt the chair back section of the Chair in one direction, then the other, several times; making certain the full backward tilt position is reached. At the same time, watch for oil leakage at the hydraulic line connections. (Pull back on the chair back section when you actuate the "Back" button for backward tilt).
If any leakage is noted, tighten compression nut slightly
as required to stop leakage. Avoid over-tightening and subsequent damage to the
NOTE: "Spongy" action of the tilt cylinder piston
indicates air remaining in the cylinder. Operate chair through full tilting
range 2 or 3 more times to remove air.
ATTACHING FOOTREST TO SEAT CUSHION See Figure 8. Mount the
footrest as shown, using the four screws, nuts and washers supplied. The
parts are to be assembled so that the screw heads and not the hex nuts are
exposed to view, and so the lock washers are under the nuts, not under the
SEAT CUSHION ASSEMBLY
CAUTION: 1. Handle the seat cushion carefully to prevent the metal upholstery clips from marking the painted surfaces of the seat frame.
damaging overflow tube ("8" in Figure 6) with the cushion
retaining brackets when attaching the cushion.
metal retaining brackets on the under- side of the seat cushion assembly,
near the back edge. These brackets will prevent the cushion assembly from
The chair should be elevated about four inches. Hold the cushion assembly at the angle shown in Figure 9, and push the assembly toward the back of the chair. When the retaining brackets “ A “ extend beneath the lip of the seat frame casting, lower the cushion assembly and continue pushing until it rests firmly within the seat frame.
LOWERING AND TILTING SPEEDS
When checking the tilting speed, do so with a man of average weight in the
chair. (You may sit in the chair yourself). Keep in mind that backward
tilt (like lowering) is accomplished not by power, but by allowing oil to
drain from the cylinder and return to the reservoir.
10. There are four solenoid valves in the Chair Base (one valve for each
direction of hydraulically-operated travel). The "Lower",
"Forward'” and' “Backward” solenoid valves have adjusting
screws which enter the passages inside the manifold, controlling the
volume of oil flow through the valve; and thereby the rate of Chair
travel. The "Raise" solenoid valve has no adjusting screw since
maximum flow through this valve is desirable.
purchaser wishes the lowering or tilting speeds changed, find the correct
adjusting screw as indicated in Figure10, loosen the 3/8" hex lock
nut for the adjusting screw and turn the screw with a screwdriver as
follows: Turn the screw clockwise to reduce speed, counterclockwise to
increase speed, never turning the screw counterclockwise more than 7-1/2
total turns from the full closed position. If the screw is turned outward
until threads disengage, oil will be forcefully expelled from the screw
hole. Maximum speed is attained when the screw is extended 2-1/2 total
turns beyond the lock nut (with nut loosen- ed slightly)
Notice that the rate of backward tilt increases as the chair back section tilts further back, due to an in- crease of weight upon the chair back. Allow for this in- crease; otherwise, the patient may experience a falling sensation if the operator uses the extreme back tilt.
ATTACHING BASE COVERS
the rear cover-mounting bracket to the lift assembly with two hex head
screws as shown in Figure 7.
Figure 11. Find the four 10-24 x 1/2" long, pan head screws, two
10-32 x 3/8" long, truss head screws and four hex nuts.
Note that the
rear cover is the one notched at the top to accept the hydraulic line trim
bushing. Slip the covers into place, from front and rear, so the mounting studs
enter the holes provided. Flex the rear cover at the sides as necessary to allow
insertion in the channels on the front cover. Fasten the covers to the lift
assembly with the 6 screws, first making certain the 10-32 x 3/8" screws
are used in the holes on each side of the rotation lock, and that there is
clearance between the covers and elevating tubes. Over- sized holes in the
covers will allow slight shifting be- fore the screws are tightened. Next, turn
the four hex nuts onto the mounting bracket studs, tightening them only until
snug. DO NOT FORCE.
Adjust the sleeve covering the hydraulic line and cords so the end enters the trim bushing.
Use the plastic clamp packed with the loose parts to clamp the coiled hydraulic line and switch wire assembly to the base, utilizing the cover screw shown in Figure 11.
The loop of the clamp must face away from the elevating tube as shown in Figure 11A.
CHAIRS MODEL F & FX MODEL TYPES F INSTALLATION FX INSTALLATION SCHEMATICS HYDRAULICS