DRIVE MECHANISM FOR A SOAP OR
The present invention relates to a device for the linear drive of a pumping member in a media dispenser and is a Continuation of PCT/CH 00/00028 filed Jan. 19, 2000.
BACKGROUND OF THE INVENTION
Electrically operated soap and/or foam dispensers for hand washing are generally activated in a contactless manner by a sensor, i.e. a hand held out at a suitable distance sets a pump mechanism in action, so a portion of soap or foam is dispensed. If the hand is withdrawn prematurely or if someone wishes to "test" the action of the dispenser by passing the hand underneath quickly, the dispensed portion falls on parts of the wash basin and/or soils the floor.
This drawback has been recognised and an attempt made to eliminate it by reversing the direction of rotation of the drive motor as set forth in DE-A1-198 05 304. Here the presence of the hand to be provided with soap is monitored during the is pumping process. The necessary change in the drive and the subsequent mechanism from a forward direction to a reverse direction represents a complete reversal in the flow of energy and causes motor currents which are a multiple of the nominal current. Repeated successive actuation of the change in the direction of rotation can overheat and damage a small motor. In addition, the control circuit has to be equipped with components (transistors/thyristors, passive elements) which can process the maximum resulting high currents and are correspondingly expensive.
The object of the present invention is therefore to create a device which manages dispensation without the reversal of a drive motor, is economical and yet satisfies the requirements in service. The subject of the invention should stop the drive when the hand to be provided with soap is not removed at the correct time such that there is no soiling of the dispenser and its surroundings. In addition, the dispenser should be ready for use again after a short time and must not incur any damage even after repeated incorrect triggering of the metering process.
This object is achieved by the use of switchable coupling members between the drive motor and a piston rod of the pump member. A sensor controls the operation of the coupling members, which disengage the pump from the motor when a hand is not in the proper position for receipt of the pumped media.
Owing to the uncoupling of the piston rod the flow of power to the pumping member is interrupted so the flow of medium is stopped immediately. The relief applied to the pumping member and corresponding elastic components is sufficient in most devices to cause minimum backlash, preventing dripping of the medium.
The switchable members may be located between a push rod and the piston rod. The push rod converts the rotational movement of the motor into an oscillating movement in a compact manner. Transmission of the movement of the push rod to a coupling link facilitates the interruption and the subsequent restoration of the flow of power.
Inclusion of a locking cam and a spring-loaded locking lever on the push rod is particularly advantageous for quick unlocking and locking, i.e. for connection to the coupling link with an interlocking fit. Electromagnetic disengagement of the locking lever can also be provided.
A connecting link can be utilized to actuate the locking lever. Rotational loading of the connecting link through a
joint head construction allows virtually any arrangement of the electromagnet and requires only small forces for uncoupling. Such a construction also allows the use of commercially available actuating magnets.
5 The joint head also allows an oscillating movement of the push rod to be converted into a linear pumping movement.
A leaf spring can be used to act on the connecting link and ensures reliable disengagement thereof.
1Q An additional restoring force f applied to the piston increases the inherent backlash in the pumping member and prevents subsequent dripping, in particular if soap flakes undergo an expansion at an inner face next to the delivery aperture. The force should be as small as possible to
s conserve energy.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will be described hereinafter with reference to drawings, in which: 20 FIG. 1 is a perspective view of a drive mechanism for a hose pump in a soap dispenser in accordance with the invention;
FIG. 2 shows the device from FIG. 1 in readiness for 25 operation, in a lateral plan view;
FIG. 3 shows the device of FIG. 2 in the pumping position (end position);
FIG. 4 shows the device according to FIGS. 1 to 3 with temporary interruption of the metering process; 30 FIG. 5 shows the drive mechanism with its battery current supply, installed in a soap dispenser to be operated in a contactless manner; and
FIG. 6 is an enlarged diagram similar to FIG. 5 using an example of a foam dispenser.
DETAILED DESCRIPTION OF THE
A drive mechanism designated 1 as used in soap and foam
40 dispensers can be seen in FIG. 1.
A commercially available electric motor M, a batteryoperated d.c. motor, is inserted in a flange 2. The housing of the motor M is held by a resiliently configured carrier 3 with holding flanges 4. A drive pinion 5 (not shown) is located in
45 the flange 2 and acts on a spur gear 6 placed on a gearing flange 7. An assembly angle 31 is arranged integrally and at a right angle on the gearing flange 7. The spur gear 6 is covered by a cover (not shown) held via clips 8 on the gearing flange 7.
50 A crank mechanism 9 with crank pin 10 projecting from a crank disc 11 and engaging in a guide groove 13 of a push rod 12 is located on the side facing the observer. The push rod 12 is mounted at one end on a swivel pin 14 and has a locking cam 12' at its opposing end. A coupling link 15
55 pivotal about a bearing journal 40 is connected with an interlocking fit at one end to the push rod 12, a latching pawl 16 locking the two components 12 and 15 in the position shown so the pawl rests with a locking lever 17 on the locking cam 12' of the push rod 12. The latching pawl 16 is
60 in turn mounted at its lower end on a swivel pin 18. A cam-like spring mount 19, on which a flat coil spring 20 is supported and presses the locking lever 17 against the push rod 12 and the locking cam 12' in this case, is located at the lower end of the coupling link 15. A joint head 21 in which
65 lateral cams 23 of a piston rod 43 are engaged is located next to and beneath the flat coil spring 20. The piston rod 43 carries a pump piston 25 and is centered on a trailing piston
guide 41, the piston 25 actuating in a manner known per se as a hose pump for a soap solution. In addition, lateral cheeks 24 providing parallel guidance with a suitable flat part (not shown) engaging therein, are located beneath the joint head 21. 5