TECHNICAL FIELD

The present invention is related to a gas tap of the type with a regulating conical plug and a rotary actuating shaft, used on a gas cooking appliance and, in particular, to a constructional feature of a cover bushing for the shaft and the tap body.

PRIOR ART

Gas taps of the type defined above, provided with a tubular-shaped cover bushing with a tubular neck at the output end of the shaft guiding the latter's rotation and with a circular base that closes against an open surface on the tap body, are known.

In GB-A-2205849 a tap for a gas cooking appliance is disclosed whose rotary actuating shaft coupled to a conical regulating plug can turn through a given angle for the supply of a gas flow between two extreme angular positions corresponding to a maximum flow and a minimum flow, starting from an initial rotation locking position. The tap cover has the shape of a tubular bushing with a dome for guiding the shaft and a larger diameter tubular cover. The actuating shaft has a rotation lock pin extending in a radial direction on a circular transverse surface at the base of the cover, travelling through a given angle between two angular positions for the supply of a maximum flow and of a minimum flow from the regulating conical plug, starting from a rotation lock â€œOFFâ€ position.

DISCLOSURE OF THE INVENTION

The object of the invention is a gas tap for a domestic cooking appliance of the type with a regulating rotary conical plug an a manual actuating shaft guided by a tubular shaped cover bushing, which is provided with means for allowing the shaft rotation between an angular locking position -OFF- and a rotation stop position -MIN- for the supply of the gas flow, giving an tactile and/or acoustic indication of the gas outlet opening.

For rotating the shaft a given angle between the two extreme positions, the rest position â€œOFFâ€ and the minimum flow position, the shaft is provided with a transverse lock pin, and the tap cover is fitted with means for covering the actuating shaft and means for supporting and guiding the shaft in its rotation, and a circular base in the cover bushing provided with a sliding surface for said transverse lock pin. Upon actuating the tap shaft, the user perceives an acoustic indication produced by the transverse pin during its angular movement when frictions over said circular sliding surface, with the cooperation of a return spring urging on the shaft axially against the circular cover base.

It is a cost-saving advantage that the tap cover can be made by means of successive press-stamping only operations, with no additional machining, including the indentations or protuberances or notches with which the circular base of the cover is provided.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial sectional view of a gas tap for a cooking appliance, provided with an actuating shaft and a tap body cover.

FIG. 2 is a perspective view of the gas tap cover in FIG. 1.

FIG. 3 is a sectional view of a detail of FIG. 1 according to line III-III.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

With reference to FIGS. 1-3, an embodiment of gas tap 1 according to the invention comprises an elongated shaped tap body 2 with a central housing 2a to accommodate a regulating conical plug 3, a hand-operated rotary shaft 4 coupled to the conical plug 3, a return spring 13 for the shaft, and a tap cover 5 which covers said central housing 2a within the tap body, and in addition acts as a guide for the rotation. The shaft 4 may rotate an angle A in either of the two directions, normally more than 180 degrees, for the supply of a gas flow G, which is determined by the position of a transverse pin 6 on the shaft (FIG. 2), from an initial rotation locking position corresponding to gas supply â€œOFFâ€ , an intermediate position of maximum gas G flow, and a final position of minimum gas G flow supplied by the tap 1. The cover 5 takes the form of a tubular bushing and comprises a narrow tubular part 5a of diameter D1 encircling the outer free end of the shaft 4 snugly, and a cylindrical part 5b of a diameter substantially larger than D1, which is provided with a sealing base 5c with two fixing tabs 9 and a circular peripheral edge 10 of diameter D2 engaged in the body housing 2a.

The circular sealing base 5c on the cover bushing presents a circular sliding surface 11 extended over an arc corresponding to said angle of rotation A, on which the transverse pin 6 slides. The sliding surface 11 takes the form of an undercut surface in the direction of the axial length of the cover bushing 4 with respect to its circular edge 10, and presents a series of radial â€œindentationsâ€ intermittently against which the friction contact of pin 6 produces a tactile and/or acoustic indication for perception by the user. The transverse pin 6 is of diameter â€œdâ€ , big enough to move reciprocally in the axial direction by itself as it passes over each of the indentations 12, while it is pressed by an axial force F exerted by the return spring 13 on the shaft 4. In the embodiment of the cover 5 in the FIG. 2 a friction surface arc 11 of around 180 degrees is preferred.

The initial shaft rotation locking position 7 is determined by a â€œUâ€ -shaped locking groove in the circular edge 10, adjacent to one arc end of the sliding surface 11. The groove 14 has an undercut depth in relation to the sliding surface 11 and a width the same as the diameter â€œdâ€ of the pin 6 housed partly in it. For the pin 6 to disengage from the locking groove 14, the shaft 2 is pushed by the user towards the inside of the tap, overcoming the force F of the spring 13, and then maximum gas G flow is supplied by means of a rotation of the shaft.

To fix the rotational end position 8 corresponding to the minimum gas flow, the circular edge 10 presents a stop wall 15 for the rotation of the transverse pin, resting on a recess 16 at the end of the sliding surface 11. From the rest recess 16 the transverse pin 6 issues only by means of rotation in the opposite direction by mounting on the indented surface 12.

The tap cover 5 may be made by means of molding a light metal alloy, being then subjected to machining of the indentations 12 and the locking groove 14. For cost-saving purposes no further performing of machining operations is preferred after the molding of the cover 5. One preferred embodiment of the cover bushing 5 is made from a metal sheet by means of successive press-stamping operations. The sealing base 5c and the circular edge 10 with the axially oriented stop wall 15 are formed in this way, and also the frictional protrusions or indentations 12 on the sliding surface 11, and the adjacent locking groove 14.