Internal by-Pass Valve for Submersible Suction Cleaner

1. Field of Invention

This invention relates to self-propelled submersible suction cleaners, particularly swimming submersible pool suction cleaners. The term "self-propelled" herein means that the suction cleaner is not manually propelled but includes means operated by the flow of water through the suction head to cause propulsion of the device.

2. Description of Background Art

Swimming pool suction cleaners often encounter large objects, such as leaves and twigs, which tend to block the flow of water through the cleaner especially at the entrance to the suction chamber of the suction head. In order to avoid the filter pump from becoming starved and the motor suffering damage, the cleaner device is typically provided with a weir by-pass valve at the coupling of the suction hose to the weir intake for the pump. Such weir, however, also collects floating debris and the weir by-pass valve is likely therefore also to be blocked. In such an event the motor for the pump may well burn out.

Furthermore with the weir by-pass valve at the weir, water will tend to flow via that route to the pump since it provides the least resistance to flow. When the flow rate drops due to clogging of the filter or the strainer at the pump, the diversion of flow via the weir by-pass valve at the weir can cause such drive power loss at the cleaner head such that the latter fails to move at all.

It is an object of the invention to provide a self-propelled submersible suction cleaner with a by-pass valve which minimizes the above danger.

According to the invention a self-propelled submersible suction cleaner includes a head having a suction chamber in which propulsion means is located for operation by waterflow into the suction chamber, the head incorporating a by-pass inlet to the suction chamber downstream from the propulsion means, a closure member for the inlet, and a spring biasing the closure member to an inlet closing position, the arrangement being one in which the spring is overcome by the suction in the suction chamber when flow into the chamber is blocked, thereby allowing water into the suction chamber via the by-pass inlet.

It will be appreciated that by providing a spring-controlled by-pass inlet into the flow stream between the propulsion means and the weir, and more specifically at the suction chamber, there is a smaller possibility of the by-pass becoming blocked. Furthermore by locating the by-pass valve directly in the suction chamber, immediately downstream of the propulsion means, the diversion of flow via the by-pass valve is limited and the suction cleaner continues to operate efficiently even though the flow rate through the filter system is reduced by clogging.

In order to illustrate the invention an example is described below with reference to the accompanying drawings in which:

FIG. 1 is a perspective view from the upper side of a self-propelled submersible suction cleaner head according to the invention; and

FIG. 2 is a section on the line II--II in FIG. 1.

Referring to the drawings, a self-propelled suction cleaner head comprises a housing 1 having a mouth 2 along which bristles 3 are disposed so that the head rests on the bristles in its operative position.

The head incorporates a suction chamber 10 within the housing 1, which suction chamber is comprised of side walls 11 and 12 and end walls 13 and 14 defining the housing peripheral walls.

An oscillator (not shown) is pivotally mounted within the suction chamber on a hinge pin journalled on side walls 11 and 12 so that the oscillator is located at the entrance to the suction chamber adjacent the mouth 2 of the head.

A connector 30 is provided on the housing 1 for a suction hose (not shown) used to connect the suction head to the filter pump of a swimming pool. Coupling the suction head to the filter pump causes flow into the suction chamber 10 via the mouth 2 of the housing 1 and the flow inpinges first on one side and then on the other side of the oscillator causing the latter to swing to and fro on the hinge pin and to impact against the housing on either side of oscillator which in turn causes the head to advance in stepwise fashion.

It is appreciated that if large objects such as leaves, twigs and the like, collect in restricted areas of the flow path past the oscillator, the flow path could become starved and if no relief or by-pass valve is provided the motor driving the pump will burn out.

In accordance with the present invention the housing 1 includes by-pass apertures 20 in the suction chamber 10 at the upper end thereof close to connector 30 for the suction hoses. These by-pass apertures are closed off by closure plate 21 pivotally mounted within suction chamber 10 on hinge pin 22. Leaf springs 23 are secured at their ends 23a on to the housing within the suction chamber 10 and at their opposite ends 23b to the closure plate 21. Thus the leaf springs bias closure plate 21 to a position closing by-pass apertures 20.

With normal operation of the suction cleaner device the restricted passages in the location of the oscillator are unblocked and the springs 23 exert sufficient force to maintain the closure plate 21 in a closed position. However, should the entrance to the suction chamber become blocked with leaves or other debris, the pressure in the suction chamber will drop abnormally. through the action of the filter pump causing the closure plate 21 to be forced away from the by-pass apertures 20 against the biasing action of springs 23. Water will thus flow into the suction chamber and the suction hose via the by-pass apertures 20 until the blockage of the suction chamber is removed. In this way by-pass apertures 20 act as a relief valve ensuring that the pump is not starved and that its motor is not endangered. It will be appreciated that the positioning of the by-pass apertures 20 downstream from the oscillator but away from the weir render it unlikely that the apertures 20 will become blocked. Furthermore it eliminates air suction at the weir when the water level is low.

The strength of springs 23 is balanced to ensure that water is drawn in via the by-pass valve in a controlled way providing regularized speed of the oscillator.