Dispenser, particularly for liquid soap

A dispenser for liquid such as liquid soap, comprising:

• means providing a reservoir disconnectably connected to a main body;
• said reservoir including a container having a first normally-closed, pressure-operated one-way outlet valve and securement means by which said reservoir may be disconnectably connected to the main body;
• said main body including an upwardly opening well for receiving a latter portion of said reservoir;
• a cylinder having a inner end in communication with said well;
• a piston slidably mounted in said cylinder and being provided with resilient means for pushing said piston back out when said piston is pushed in;
• releasable securement means on said main body for cooperation with said securement means on said reservoir to disconnectably connect the reservoir to the main body;
• means defining a dispensing chamber in said cylinder inwardly of said piston;
• means defining a portion from said well to said chamber;
• said one-way outlet valve being disposed to open through said opening into said chamber and said reservoir being sealed to said cylinder perimetrically of said opening when said reservoir is connected to said main body;
• a second normally-closed, pressure-operated one-way outlet valve from said cylinder, having an upstream side in communication with said chamber;
• and a vent tube for said reservoir extending from the headspace therein, at atmosphere, so that as said piston is pushed-in, the pressure in said dispensing chamber is raised, causing only said second valve to temporarily open and to dispense a quantum of liquid from said dispensing chamber and as said piston is released and pushed back out the pressure in said dispensing chamber is lowered, causing only said first valve to temporarily open and to replenish said dispensing chamber with a quantum of liquid from said reservoir,
• said securement means for disconnectably connecting the reservoir to the main body comprising a plurality of lateral protuberances on the main body which fit into corresponding laterally opening recesses provided on cantilevered resilient tabs on the main body;
• these tabs having externally presented releasing buttons which may be pushed inwards to flex the tabs inwards and thus free the securement means;
• and
• a locking means for preventing accidental disconnection of the reservoir from the main body, said locking means comprising a fixture normally disposed within the main body and mounted therein for limited angular movement;
• said fixture having tab means protruding out through the main body for external access;
• said fixture including stop means which in one angular position of said fixture abuttingly back-up said releasing buttons and prevent said releasing buttons from being pushed in sufficiently to free the aforesaid lateral protuberances on the reservoir from the aforesaid laterally opening recesses on the main body and which in another angular position of said fixture are out from behind said releasing buttons so that said releasing buttons may be pushed in sufficiently to disconnect the reservoir from the main body.