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(11) | EP 0 690 231 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Hermetic quick coupling for safety valves of tires |
| (57) A hermetic quick coupling for safety valves for tires, including, at the end of the
pump body, a tubular chamber (9) that is connected to the compression cylinder (6)
of the pump through a central radial hole (10); a bush (11) is hermetically and slidingly
fitted inside the tubular chamber (9) and is frontally provided with a rigidly coupled
end of a bell-shaped element (19) that forms a seat for a sealing rubber fitting (20)
together with the bush (11), the other end of the bell-shaped element (19) being flexible;
when the valve (2) is manually pushed against the bush (11) towards the inside of
the chamber (9), the bell-shaped element (19) is adapted to interfere with the opening
of the chamber (9), clamp the safety valve (2), and tighten the rubber fitting (20)
perimetrically on the end of the valve (2); the bush (11) is hermetically crossed,
at the rear, by a stem (25) that is rigidly coupled to the bottom (24) of the chamber
(9) and is adapted to actuate the shutter of the valve (2) when the safety valve (2),
clamped by the bell-shaped element (19), enters. |
[0001] The present invention relates to a hermetic quick coupling for safety valves of tires, to be installed in hand pumps, motorized pumps, and pressure gauges.
[0002] Conventional safety valves for tires have a thin stem at their end, on the opening of the inflation duct; said stem is monolithic with the valve shutter and must be pressed mechanically in the direction in which air is introduced in order to open and allow inflation.
[0003] These valves, commercially known as Schrader valves, have the drawback that the connection between the valve and the air delivery nozzle is achieved by means of couplings that entail air leaks during coupling and uncoupling; in some cases, especially when the personnel is inexperienced, these leaks can also be very large: air leakage during coupling to the pump is particularly negative when inflating small volumes at high pressure.
[0004] The aim of the present invention is to obviate the drawbacks of conventional devices, that is to say, to provide a hermetic quick coupling for safety valves of tires that does not entail any leakage of air during use and can be easily used even by inexperienced personnel.
[0005] An object of the present invention is to achieve the above-mentioned aim with a structure that is simple, relatively easy to produce, safe in use, reliable in operation, and has relatively low cost.
[0006] This aim and this object are both achieved by the present hermetic quick coupling for safety valves for tires, characterized in that at the end of the pump body there is a tubular chamber connected to the compression cylinder of the pump through a central radial hole; a bush is hermetically and slidingly fitted inside the tubular chamber and is frontally provided with a rigidly coupled end of a bell-shaped element that forms a seat for a sealing rubber fitting together with the bush, the other end of said bell-shaped element being flexible; when the valve is manually pushed against the bush towards the inside of the chamber, said bell-shaped element is adapted to interfere with the opening of the chamber, clamp the safety valve, and tighten the rubber fitting perimetrically on the end of the valve; said bush is hermetically crossed, at the rear, by a stem that is rigidly coupled to the bottom of the chamber and is adapted to actuate the shutter of said valve when said safety valve, clamped by the bell-shaped element, enters.
[0007] Further features will become apparent and evident from the detailed description of a preferred but not exclusive embodiment of a hermetic quick coupling for safety valves for tires according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
figure 1 is a sectional side view, taken along a median plane, of a hermetic quick coupling for safety valves for tires according to the invention;
figures 2 and 3 are sectional side views of the valve of figure 1 in successive functional configurations;
figures 4 and 5 are sectional side views, taken along a median plane, of another embodiment of the quick coupling according to the invention, in the configurations it assumes when it is engaged with a valve and respectively disengaged from it.
[0008] With particular reference to the above figures, the reference numeral 1 generally designates a hermetic quick coupling for safety valves 2 for tires according to the invention: the valves 2 are of the kind commercially known as Schrader valves, are usually used for tires of cars, trucks, motorcycles, mountain bikes, or the like, and are axially provided with a stem 3 that extends from the movable shutter and must be pressed towards the inside of the valve (arrow A), to allow to open said valve; the valve is provided with a thread 4 on its outer surface.
[0009] The reference numeral 5 designates the body of a pump, the reference numeral 6 designates the bottom of the compression cylinder, the reference numeral 7 designates the piston, and the reference numeral 8 designates the check valve: the figures show the coupling fitted to a hand pump, but it is possible to fit the coupling also to mechanically-actuated pumps, compressors, or other devices.
[0010] A tubular chamber 9 is provided at the end of the body 5, and its axis lies at right angles to the body 5; said chamber is connected to the inflation hole of the pump through a central radial hole 10.
[0011] A bush 11 is slidingly mounted in the tubular chamber 9 and is provided with two external annular grooves 12, 13 for accommodating two toroidal sealing rings 14 and 15, conveniently of the type known as O-Ring, against the inner surface of the chamber 9: between the two annular grooves 12 and 13, the outer surface of the bush is affected by a peripheral recess 16 and is provided with at least one through hole 17.
[0012] A threaded end 18 of a bell-shaped element 19 is screwed onto the front end of the bush and forms, together with the bush, a seat for accommodating a profiled sealing rubber fitting 20; at the other end, the bell-shaped element 19 has longitudinal slits that form several, for example four, flexible jaws 19a; the cylindrical inner surface of the jaws 19a is affected by a threaded portion 19b, and the bell-shaped element 19 is advantageously made of a material such as plastics and in particular of the material known by the trade-name Nylon.
[0013] A ring 21 is screwed onto the front end of the chamber 9 and forms, at the opening, an inner rounded tooth 22 that is adapted to cooperate with a corresponding rounded external annular recess 23 of the end of the bell-shaped element to lock said bell-shaped element in the configuration in which it is locked onto the valve.
[0014] A bottom 24 is hermetically screwed onto the chamber 9 at the rear and is provided with an axial stem 25 that is rigidly coupled thereto and is provided with an annular slot 26 for a toroidal sealing ring 27 of the type known as O-Ring against the inner surface of the internal axial hole 28 of the bush 11; the stem 25 hermetically passes through the bush 11 and has a tapering tip 29.
[0015] Elastic means 30 are fitted between the bottom 24 and the bush 11 and are constituted, in this particular case, by a helical compression spring; said means are adapted to push the bush in the direction for exiting from the bell-shaped element.
[0016] The operation of the coupling according to the invention is simple and is shown schematically in figures 1, 2, and 3.
[0017] The safety valve, shown in figure 1, is manually inserted in the bell-shaped element, and its end presses against the bottom of the rubber fitting 18, producing a front seal: by continuing to press, the bell-shaped element gradually enters the chamber 9 and interferes with its opening, which pushes the jaws towards the axis of the bell-shaped element to clamp the safety valve and perimetrically tighten the rubber fitting on the end of the valve (figure 2) so as to provide a perimetric seal; by pressing further, the shutter 3 is pushed against the end of the stem 29 that opens it; at the end of the stroke, the bell-shaped element is locked, in the condition in which it lies inside the chamber 9, by the annular tooth 22, which enters the slot 23 of the bell-shaped element: in practice, the shutter 3 is opened only after the rubber fitting 18 has ensured frontal and perimetric tightness and after the jaws 19a have mechanically clamped the valve, while the annular tooth 22 and the slot 23 lock the coupling, so as to avoid, during inflation, the mutual movements between the valve and the rubber fitting that usually occur in conventional couplings and inappropriately stress the rubber fitting.
[0018] In the embodiment shown in figures 4 and 5, the bush 11 can be released manually, rather than by means of the spring 30: in this embodiment, the bush 11 extends with two curved stems 31a, 31b that pass through two corresponding curved through slots 32a, 32b of the bottom 24; the stems 31a, 31b are inserted by pressing in corresponding blind seats 33a, 33b of a cap 34 which can be released in the direction of the arrow A, preferably using the thumb of the hand that holds the pump body.
[0019] In order to operate also on normal valves, the tip 29 is separate from the stem 25: the stem 25 ends with an axial hole 25a into which one or the other of the two tapered tips 29a, 29b, having a star-shaped cross-section of appropriate length for operating on normal valves (29b) or on Schrader valves (29a), is inserted snugly; in this respect, it is also necessary to replace the bell-shaped element 19 with another bell-shaped element having jaws of adapted size.
[0022] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.
[0024] In practice, the materials employed, as well as the dimensions and shapes, may be any according to the requirements without thereby abandoning the scope of the claims that follow.
[0025] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.
1. Hermetic quick coupling for safety valves for tires, characterized in that at the
end of the pump body there is a tubular chamber (9) that is connected to the compression
cylinder (6) of the pump through a central radial hole (10); a bush (11) is hermetically
and slidingly fitted inside the tubular chamber (9) and is frontally provided with
a rigidly coupled end of a bell-shaped element (19) that forms a seat for a sealing
rubber fitting (20) together with the bush (11), the other end of said bell-shaped
element (19) being flexible; when said valve is manually pushed against the bush (11)
towards the inside of the chamber (9), said bell-shaped element (19) is adapted to
interfere with the opening of the chamber (9), clamp the safety valve (2), and tighten
the rubber fitting (20) perimetrically on the end of the valve (2); said bush (11)
is hermetically crossed, at the rear, by a stem (25) that is rigidly coupled to the
bottom (24) of the chamber (9) and is adapted to actuate the shutter of said valve
(2) when said safety valve, clamped by the bell-shaped element (19), enters.
2. Coupling according to claim 1, characterized in that said tubular chamber (9) lies
at right angles to the compression chamber (6) of the pump.
3. Coupling according to claim 1, characterized in that said tubular chamber (9) is aligned
with the compression chamber (6) of the pump.
4. Coupling according to claim 1, characterized in that a ring (21) is fitted at the
front of the chamber (9) and forms, at the inlet, an internal rounded tooth (22) that
is adapted to cooperate with a corresponding external rounded annular recess (23)
of the end of the bell-shaped element (19) in order to lock the bell-shaped element
(19) in the configuration for clamping onto the valve (2).
5. Coupling according to claim 1, characterized in that elastic means (30) are mounted
between said chamber (9) and said bush (11) and are adapted to push said bush (11)
in the direction for exiting from said bell-shaped element (19).
6. Coupling according to claim 1, characterized in that said bush (11) extends with at
least two stems (31a,31b) that pass through corresponding slots (32a,32b) of said
bottom (24) and engage in a manual release cap (34).