Dynadjust Ritter Dental Chair Models E

Installation Instructions



Filling Oil Reservoir

Place the chair base in the desired location and pour the two cans of Ritter Hydraulic Oil into the elevating tube as shown in Figure 7. 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.



Expelling Entrapped Air From Base

After filling the reservoir, it is necessary to expel all air from the power unit and lift tube. Unscrew the pump priming valve about two full turns (See Figure 9), then unscrew the vent screw about one full turn ( See Figure 8) .Take care not to force the vent screw beyond the point to which it turns easily.

NOTE: Although the power unit must be running steadily throughout the following procedure, do not run the power unit any longer than necessary (thirty seconds should be sufficient) .The reason for this is, that until the chair top is mounted on the base, the power unit pump does not develop full oil pressure and, therefore, does not give full lubrication to its bearing.


Move the selector lever to the "Raise" position and run the power unit until oil flows steadily from the pump priming valve, then close the valve tightly. Continue to run the power unit until oil flows steadily from either side of the vent screw; then turn the vent screw down. As soon as oil pressure builds up in the lift tube and the elevating tubes start rising, immediately loosen the vent screw. Repeat the action of tightening and loosening the vent screw a few times to expel any remaining air I then turn the vent screw down 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 Power Unit Cover

Remove the four screws from the envelope marked "Screws for Attachment of Power Unit Cover". Thread the two shouldered screws into the chair base, to the shoulders. (See Figure 9).  Slide the floor cord out through the opening in the cover as far as the strain relief permits, and attach the cover, fastening it at the bottom with the two round head screws. It is important that these screws are securely tightened, drawing the cover tight against the chair base.

Attaching Seat Frame to Chair Base



By means of the selector lever, raise the elevating tubes about four inches above the top of the base cylinder. This is done to prevent possible marring of the base covers. Position the seat frame on the Chair Base in the relationship indicated by Figure 1, 1 A or 1 B; then secure the centerpiece to the inner elevating tube with the four hex head screws provided. (See "P" in Figure 10) .A cloth bag containing the four screws is tied to the centerpiece. Tighten the four screws securely.

If the chair is a Type 3, wipe the back supporting bar clean, then moisten with Ritter Engine Oil to assure easy tilting adjustment. See Figure 22.

Hydraulic Line Connection-Chair Top to Base -Type for 2 Chair

NOTE: Air must be expelled from both sections of the line before they are connected.

Refer to Figure 10. Pull the end of the air vent tube " A " from the hole in the centerpiece. Remove the cap from the Union "B" on the grey nylon line and hold the end of this line in the hole in the centerpiece. Move the selector lever to the "Forward" position and allow the power unit to run until air-free oil flows from the grey nylon line. (The oil expelled from the nylon tube will be returned to the reservoir in the Chair Base).

Hold the chairback section securely upright while removing the plug from the copper line. Hold a cloth around the open end of the copper line and tilt the chairback section backward manually, a very slight amount, to expel a small amount of oil from the copper line; then quickly join the nylon and copper sections of the line as follows:

1. Hold the Union "B" (Figure 10) with a 7/16" wrench

2. Tighten compression nut "C" finger-tight; then tighten with a V2” wrench until snug. Do not force.

3. Operate the selector lever to tilt the chairback section of the chair in one direction, then the other, several times; watching for oil leakage at the connection made in steps 1 and 2.

NOTE: Pull back on the chairback section when you put the selector lever in position for backward tilt.

4. If any leakage is noted, tighten compression nut "C" or "D" slightly as required to stop leakage. Avoid over-tightening and subsequent damage to the parts.

5. Secure the uppermost coil of the grey nylon line with the clamp "E" on the underside of the centerpiece, as shown in Figure 10. Clamp the line at a point which will allow plenty of slack in the coils and a minimum of slack between the clamp and the fittings connected in steps 1 and 2.

CAUTION: When connecting and clamping the nylon line, avoid bending the copper line downward, as this may place the connection fittings in a position where they will strike the chair base when the chair is lowered. Check for this condition, and bend the copper line upward slightly, if necessary, to prevent marring of the finish on the chair base.

Now, place the end of the air vent tubing back in the hole in the centerpiece.

NOTE: If, through accident, air is allowed to enter the tilting cylinder, operate the chair through the full forward tilt and backward tilt range 2 or 3 times to remove the “spongy" feel of the piston movement in the cylinder.

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 set screw. Loosen the set screw 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. Tighten the set screw.

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; 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 Footrest to Seat Cushion- Type 1 Chair

See Figure 11.  Mount the footrest as shown, using the four screws, nuts and washers found in the cloth bag in the footrest box. 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: Handle the seat cushion carefully to prevent the metal upholstery clips from marking the painted surfaces of the seat frame.

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 four inches. Hold the cushion assembly at the angle shown in Figure 12, 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. A screw in front of the seat frame prevents cushion "play".


Attaching Foot Platform-Type 2, 3 or "M" Chair

The chair should be elevated about four inches. Attach the foot platform to the seat frame with the four screws provided. See mounting holes "N" in Figure 10. An envelope containing the four screws is packed inside the cardboard fold up for the headrest. Tighten all four screws securely.

Removing Contour Cover From Valve Opening in Base

See Figure 13. The cover is retained by one screw, at the bottom, Remove the screw and slip the cover downward and outward. Reverse this procedure to mount the cover, making sure the small clip at the top of the cover is placed inside the valve opening in the base casting,



Adjusting the Lowering, Raising and Tilting Speeds

There are four solenoid valves in Type 1 and 2 Chair Bases, two solenoid valves in Type 3 Bases (one valve for each direction of hydraulically operated travel).  Each solenoid valve has an adjusting screw which can enter the passage inside the valve, affecting the volume of oil flow through the valve; and thereby the rate of Chair travel. Figure 14 shows the position of solenoid valves in Type 1 and 2 Chairs; however the "Raise and Lower" solenoids are similarly placed in Type 3 chairs, which have no "Backward" or "Forward" solenoids.

NOTE: The adjusting screw in the "Raise" solenoid valve is factory-adjusted for maximum speed.

If the Doctor wishes the speed of any hydraulically operated travel changed, find the proper solenoid valve as indicated in Figure 14 and turn the adjusting screw with an offset screwdriver or the tool packed inside the power unit cover. Turn clockwise to reduce speed or turn counter- clockwise to increase speed. Do not turn the stop screw which serves only to prevent the adjusting screw from coming out of the valve body altogether.

IMPORTANT: When checking the tilting speed on a Type 1 or 2 Chair, do so with a man of average weight in the chair. (You may sit in the chair yourself, holding the control box.) 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.

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

Back To Dynadjust Index