Ritter Dental Vega Chair
Models FX 

Installation Instructions 

   
FIGURE 3

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.

  
FIGURE 4

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

After filling the reservoir and attaching the lift Assembly and wires, it is necessary to expel all air from the lifting system.
*Temporarily connect the black, white and green (ground) wires of the 8-wire power cord to the power
*If inserting cord in Unit, turn off power supply Unit, or tape wire ends to insulate them.  supply. (See Page 9, "Permanent Power Connection for Base" for complete information). With the base connected to the power supply, proceed as follows:

  1. Turn the vent screw (Figure 5) counterclockwise about one full turn using a large screwdriver. Never force the vent screw beyond the point to which it turns easily.

FIGURE 5

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:

  4, Finally, turn the vent screw down securely to in- g.ure 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.

 
FIGURE 6

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 as indicated. 

 
FIGURE 7

HYDRAULIC LINE 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.

  Raise the base to the high position, using the jumper wire as described in step 2 on this page. (See Figure 5) With the hydraulic line and switch cord assembly coiled twice around the elevating tubes, pass the ends of the hydraulic line and cords through the trim bushing as shown in Figure 7. Remove the cap from the manifold fitting indicated, then remove the connection line plug and connect the line to the manifold fitting. Tighten the connection nut finger tight, plus 1-1/2 turns with a 1/2" open-end wrench.

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 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.

FIGURE 8

 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 screw heads.

FIGURE 9

ATTACHING 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.

2. Avoid damaging overflow tube ("8" in Figure 6) with the cushion retaining brackets when attaching the cushion.

There are metal retaining brackets on the under- side 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 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.

ADJUSTING LOWERING AND 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 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.

FIGURE 10

If the 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)

Tighten the lock nut securely after the adjustment is completed.

    
FIGURE 11

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

Assemble the rear cover-mounting bracket to the lift assembly with two hex head screws as shown in Figure 7.

Refer to 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.

 
FIGURE 11A  

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.