Sanitary mixing unit

A sanitary mixing unit, especially in the form of a single thermostat, has a cold and hot water inlet and a mixed water outlet. Valves for shutting off and controlling the water flow are arranged before the thermostat control and thus before the mixing chamber in the direction of flow. The valves are simultaneously activatable by a spindle. The movable valve closing members are fine adjustable independent from one another relative to the respective valve seats for a secure shut-off. An automatic fine adjustment of the movable valve closing members during shut-off of the mixing unit is provided by employing a central spindle with a fixedly arranged toothed wheel at its end section facing the valves. The toothed wheel engages two spur gears which are cooperating via a slip coupling with two single spindles of the valves.

BACKGROUND OF THE INVENTION 
The invention relates to a sanitary mixing unit in the form of a single 
thermostat with a cold water and a hot water inlet and a mixed water 
outlet and with valves for shut-off and flow control arranged in the 
direction of flow before the thermostat control and thus before the mixing 
chamber, the valves being actuatable simultaneously via a spindle, whereby 
the movable valve closing members are fine adjustable independent from one 
another relative to the corresponding valve seats for a secure shut-off. 
Mixing units of the aforementioned kind are known from German Patent 23 55 
101. A so called control axle in the form of a spindle is provided on 
which two valve cones functioning as valve closing members for the 
shut-off and flow control of the cold and the hot water are arranged 
whereby one of the valve cones is adjustable relative to the control axle. 
Due to such an arrangement, a fine adjustment of the valve cones relative 
to the corresponding valve seats may be performed independent from one 
another at any time if a secure shut-off is not or no longer possible; 
however, for such a fine adjustment a demounting of the shut-off and flow 
regulating handle as well as the use of tools is necessary. 
It is therefore an object of the invention to eliminate this disadvantage 
and to provide a sanitary mixing unit of the aforementioned kind in which 
a possible fine adjustment of the movable valve closing members occurs 
automatically during shut-off of the mixing unit. 
SUMMARY OF THE INVENTION 
This object is inventively solved essentially by providing the spindle as a 
central spindle and by providing a toothed wheel at its end section facing 
the valves which is engaged by two spur gears which are cooperating via a 
slide coupling with two individual spindles for the valves. 
The thermostat-controlled sanitary mixing unit according to the present 
invention comprises essentially a thermostat control; a flow control 
comprised of a central spindle and a cold water inlet and a hot water 
inlet, and further comprising a first valve connected to the cold water 
inlet and a second valve connected to the hot water inlet, the first and 
the second valves serving to shut off and control water flow, the spindle 
simultaneously activating the first and second valves; the first and the 
second valves each comprising a movable valve closing member and a valve 
seat, the valve closing members being fine adjustable relative to the 
corresponding valve seat independent of one another for a secure shut-off; 
the central spindle comprising a toothed wheel that is fixedly attached to 
one end of the central spindle facing the valves; and each valve 
comprising a single spindle connected with one end to the valve for 
activating the valve, the single spindle comprising a bearing ring fixedly 
connected to a free end of the spindle and a spur gear connected to the 
bearing ring so as to be movable relative to the bearing ring, the spur 
gear engaging the toothed wheel, with the bearing ring and the spur gear 
forming a slip coupling. 
It is expedient that the bearing ring has an outer collar and the spur gear 
has an inner collar, the inner collar of the spur gear resting on said 
outer collar of the bearing ring. The mixing unit further comprises a 
spring ring cooperating with the inner collar, and the bearing ring 
further comprises a peg for supporting the spring ring and for pressing 
with that spring ring the inner collar against the outer collar for 
effecting the slip coupling. 
Preferably, the peg has an outer beaded edge for holding and supporting the 
spring ring. 
From U.S. Pat. No. 2,332,995 as well as from British patent GB-A-492 052 
sanitary mixing units are already known which have valves within the cold 
and hot water inlets equipped with spur gears cooperating with a toothed 
wheel of a central spindle for controlling water flow. The U.S. patent 
also shows a thermostat-controlled mixing unit. However, the connection 
for achieving this cooperation is permanent such that in any operational 
condition a form-locking connection is effective. An adjustment especially 
of only one of the valves is thus impossible during shut-off. 
Inventively, the slide coupling is automatically effective in cases when 
during the shut-off of the mixing unit one of the valve closing members 
does not completely close the corresponding water opening simultaneously 
with the other valve closing member. In such a case a relative movement 
between the spur gear and the bearing ring of the already closed valve 
occurs due to a slight further movement of the central spindle since its 
end abutment has already been reached and, on the other hand, via the 
central spindle the single spindle of the other valve is simultaneously 
activated until a complete shut-off has been achieved which automatically 
results in a fine adjustment of the corresponding valve closing members 
relative to the respective valve seat.

A cold water inlet is indicated at 3, a hot water inlet at 4 and a mixing 
chamber, respectively, a mixed water outlet is indicated at 5. In the flow 
direction, before a conventional and thus not further explained thermostat 
control 6 with an actuating handle 7 for the temperature preadjustment and 
thus before the mixing chamber 5, a cold water valve 8 and a hot water 
valve 9 5, a cold water valve 8 and a hot water valve 9 are provided from 
which the water via openings 10 and 11 flows into the thermostat control 
6. The valves 8 and 9 serve as shut-off and flow control means and are 
comprised of a cartridge-like component which is screwed into the mixing 
unit housing 12. The control elements, not shown in the drawings, are 
disks made of aluminum oxide whereby one of them functions in a 
conventional manner as a stationary valve seat and the other as a movable 
valve closing member. 
The valves 8 and 9 are simultaneously driven via a central spindle 13 and 
an actuating handle 14. For this purpose, the central spindle 13 at its 
end section facing the valves 8 and 9 is provided with a fixedly arranged 
toothed wheel 15 which is engaged by two spur gears 16 and 17 which, in 
turn cooperate with two single spindles 18 and 19 for the valves 8 and 9. 
From FIG. 2 it may be taken in particular that the spur gears 16 and 17, 
for the formation of a slip coupling, are mounted on two bearing rings 20 
and 21. The bearing rings 20 and 21 are fixedly arranged on free knurled 
ends of the single spindles 18 and 19 the rotational movement of which is 
limited by abutments 22 and 23. 
The bearing rings 20 and 21 are provided with an outer collar 24. The spur 
gears 16 and 17 are supported with one side of an inner collar 25 at the 
outer collar 24. The other side of the inner collar 25 cooperates with a 
spring ring 26 which is held on a peg 27 of the bearing rings. This spring 
ring 26 presses, for the formation of the slide coupling, the inner collar 
25 of the spur gears 16 and 17 against the outer collar 24 of the bearing 
rings 20 and 21. The peg 27 is provided with a beaded edge 28 for axially 
holding and supporting the spring ring 26. 
Should during the shut-off of the mixing unit one of the movable valve 
closing members not close the respective water opening completely, for 
example, the water opening of the cold water valve 8, simultaneously with 
the other valve closing member, the slide coupling on the side of the 
already closed hot water valve 9 is activated since its abutment 23 
prevents a further rotation of the single spindle 19. Via the central 
spindle 13 the single spindle 18 of the cold water valve 8 is further 
activated until the shut-off is complete and thus until the second 
abutment 22 is effective. In the direction of closing only the spur gears 
16 and 17 of the single spindles 18 and 19 may now be turned. 
According to the invention, during the shut-off process a possibly required 
fine adjustment of the movable valve closing members relative to the 
corresponding valve seat will be automatically performed so that always a 
secure shut-off is ensured and mounting as well as service tasks are 
facilitated. 
Furthermore, cross-flow risks are also prevented due to the shut-off taking 
place in the direction of flow before the mixing chamber 5, i.e., the 
introduction of hot water into the cold water inlet or vice versa is 
prevented. For a shut off that is located behind the mixing chamber in the 
direction of flow, additional check valves are required which, however, 
cannot guarantee a secure functioning especially at low pressures, which 
has been proven in practice. 
The represented and described embodiment is only one example for realizing 
the invention, and the invention is not limited to this embodiment; thus, 
within the scope of the inventive idea other embodiments and applications 
are possible. For example, the valves 8 and 9 could be provided with 
axially movable valve closing members, such as so-called valve cones, and 
furthermore, the application of the inventive slide coupling is also 
suggested for other valve constructions. 
The present invention is, of course, in no way restricted tot he specific 
disclosure of the specification and drawings, but also encompasses any 
modifications within the scope of the appended claims.