Ritter Dental Vega Chair
Models F

  Installation Instructions       



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 Platform Assembly

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.

Attaching Cover Mounting Bracket and Control Box

Assemble the rear cover mounting bracket to the lift assembly with two hex head screws as shown in Figure 8. The screws will be found in place in the lift assembly.

Attach the control box cord wires to the connection block shown in Figure 8, and according to the wiring diagram inside the rear base cover.  Connect the green ground wire to the metal mounting plate as shown in figure 8, using the brass screw furnished


Expelling Entrapped Air from Lift System

After filling the reservoir and attaching the lift assembly and wires, it is necessary to expel all air from the lifting system.

1. If no permanent electrical connection has been made, temporarily connect the black, white and green (ground) wires of the power cord to the power supply.

2. Turn the vent screw (Figure 13) counterclockwise about one full turn using a large screwdriver. Never force the vent screw beyond the point to which it turns easily.

3. Move the selector lever to the "Raise" position and run the power unit for about 10 seconds; keep the motor running, and tighten and loosen the vent screw 3 or 4 times in rapid succession, stopping with the screw tightened.

NOTE: If the tubes should rise to the point where the screw- driver will not reach the vent screw, move the selector lever to the "Lower" position and push the tubes down with your foot; then proceed.

4. Finally tighten the vent screw securely to insure a good seal. Use a large screwdriver to tighten the screw as securely as possible; then, with the screwdriver in the screw slot, tap the screwdriver gently with a hammer and tighten the screw further.

Attaching Seat Frame to Chair Base

Operate the Control Box to raise the elevating tubes about 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 1 5/8 long, hex head screws provided. (See "P” in Figure 14) Tighten the four screws securely.

NOTE: Make certain the overflow tube ("A" in Figure 14) enters the hole in the centerpiece as indicated.



Hydraulic Line Connection-Chair Top to Base- Type 1 Chair

NOTE: After the line is connected, air must be expelled from the tilting system as described on this page.

With the grey plastic connection line coiled twice around the elevating tubes, pass the end of the line through the trim bushing as shown in Figure 15. Remove the cap from the manifold fitting indicated, then HOLD THE CHAIRBACK SECTION SECURELY UPRIGHT while removing the connection line plug and connecting the line to the manifold fitting. Tighten the compression nut finger tight, plus 1 1/2 turns with a 1/2" open-end wrench.


Expelling Entrapped Air from Tilting System-Type 1 Chair

Operate the selector lever to tilt the chair back to the extreme forward and extreme backward positions several times; at the same time watching for oil leakage at the hydraulic line connections. (Pull back on the chair back section when you actuate the control box 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 parts.

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 Backrest Cushion Assembly

The connecting pin for the backrest cushion assembly is held in the hub near the top of the backrest slide assembly, by means of a setscrew. Loosen the setscrew and remove the pin. Attach the cushion assembly to the backrest slide, using the connecting pin, and placing the spacer washers (in envelope) on the pin; one at each side of the cushion bracket. (If pin won't slide through easily, one washer may have dropped into groove in pin.) Tighten the setscrew.

CAUTION: When raising backrest cushion to gain access to set screw, do not allow cushion mounting bracket to strike top of back slide assembly, causing damage to finish.

Attaching Headrest

Remove the tape holding the roller in place. Hold the roller in the same position, raise the release lever, which clamps the roller in place; and then insert the headrest slide into the channel in the back slide. Push down on the headrest slide until the plunger on the inner side of the slide strikes the obstructing edge of the back slide casting. Using a screwdriver, force this plunger inward, and at the same time pull up on the release lever of the headrest slide. The headrest assembly will then drop into its slide.  


Attaching Foot Platform- Type 3 or "M" Chair

The Chair should be elevated about six inches. Attach the foot platform to the seat frame with the four 1 " long, hex head screws provided. See mounting holes "N" in Figure 14. Tighten all four screws securely.

Attaching Footrest to Seat Cushion Type 1 Chair

See Figure 16. Mount the footrest as shown, using the four V4"-20 x 1" long 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 screw heads.



Attaching Seat Cushion Assembly Type 1 Chair

CAUTION: 1. Handle the seat cushion carefully to prevent the metal upholstery clips from marking the painted surfaces of the seat frame.

2. Avoid damaging overflow tube ("A" in Figure 14) with the cushion retaining brackets when attaching the cushion.

There are metal retaining brackets on the underside of the seat cushion assembly, near the back edge. These brackets will prevent the cushion assembly from tipping forward.

The Chair should be elevated about six inches. Hold the cushion assembly at the angle shown in Figure 17, 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 until it rests firmly within the seat frame. The screw in the front of the seat frame should be turned inward as required to prevent cushion “play."



Adjusting Lowering or Tilting Speeds

IMPORTANT: 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.

See Figure 18. There are four solenoid valves in Type 1 Chair Bases (one valve for each direction of hydraulically- operated travel). Type 3 Bases have only one solenoid valve; for Lowering. .

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.

If the purchaser wishes the lowering or tilting speeds changed, find the correct adjusting screw as indicated in Figure 18, 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 ˝ total turns beyond the lock nut (with nut loosened slightly). Tighten the lock nut securely after the adjustment is completed.

Notice that the rate of backward tilt increases as the chair back section tilts further back, due to an increase of weight upon the chair back. Allow for this increase; otherwise, the patient may experience a falling sensation if the operator uses the extreme back tilt.

Attaching Base Covers

In the carton with the covers, find the four # 10-24 x ˝” long pan head screws, two # 10-32 x 3/8” long truss head screws and four hex nuts.

Refer to Figure 19. The front (motor) cover, which is the cover having no control box bracket should normally be mounted *first. Slip the cover into position from the front so the mounting studs will enter the holes near the bottom of the cover. Without fully tightening the screws, attach the cover to the lift assembly with two # 10-24 x 1/2" long pan head screws at the top, one # 10-32 x 3/8" long truss head screw at the side near the rotation lock, and two hex nuts on the mounting bracket studs. Do not tighten the hex nuts.


Attach the rear {valve) cover in a similar manner, flexing the sides as necessary to insert them in the *channels on the edges of the front cover. If the Chair is a Type 1, one of the cover mounting screws will be used as indicated in Figure 19 to secure the tubing clamp and coiled hydraulic line. The tubing clamp is packed with the base cover mounting components.

The covers have oversized mounting holes, which allow slight shifting before the screws are tightened. After both covers are attached, make sure there is clearance around the outer elevating tube and position the hydraulic line clamp to hold the tubing away from the elevating tubes; then tighten the six cover retaining screws securely. Tighten the hex nuts only until snug.

* If the Chair is left Hand, the rear cover will have the trim channels and should normally be mounted first.