The invention relates to an oil filler cap, for mounting in an engine oil filler tube with a back flow preventing float ball valve, where the cap includes a device to prevent sticking of the ball in the valve seat.
Engines and other machines usually include an oil filler tube to check and modify the oil volume within an oil tank. In the case of aircraft engines, the oil tank is pressurized and loss of oil during flight leads to rapid overheating of the bearings and catastrophic engine failure. In the event that the oil filler tube cap has been improperly placed or omitted altogether, oil filler tubes include a ball valve to impede oil leakage.
U.S. Pat. No. 1,756,976 to Ehlers shows a float ball valve to prevent escape of oil. Another example is shown in U.S. Statutory Invention Registration No. H438 to Viksne et al. which includes a float ball valve to prevent overflow of fuel through a fuel sounding tube.
An acknowledged problem with ball valves is that the float ball often sticks to the valve seat after operation of the engine particularly when the oil tank is pressurized and the float ball is forced by pressure into engagement with the valve seat. The relatively light weight ball of the valve can be stuck to the valve seat due to the viscosity of the oil, surface tension of oil, a vacuum state may be created that maintains the ball in place or the ball may be slightly distorted due to the pressure applied to it during engine operation. The blockage of the filler tube by the float ball stuck to the valve seat creates difficulty in adding oil to the tank through the filler tube and may give the false impression that the oil tank is full once oil is poured into the blocked filler tube.
It is an object of the invention to provide an oil filler cap that include a device to automatically prevent sticking of the ball within the ball valve and eliminate the potential for human error in judging the volume of oil within the engine.
Further objects of the invention will be apparent from review of the disclosure, drawings and description of the invention below.
The invention provides a cap for sealing an outer end of an oil filler tube of an engine where the oil filler tube has an inner end with ball valve having a float ball and mating valve seat for impeding any reverse flow of oil during engine operation. The cap includes a sealable plug mating the tube outer end; a rod extending from the plug toward the inner end of the tube; and a valve opening device mounted to the rod for dislodging the float ball from the valve seat.
One example of a valve opening device is a resilient tip mounted to the inner end of the rod where the rod has a length sufficient to reach down the oil filler tube and dislodge the ball from the valve seat. In order to permit the ball valve to remain in operation, the resilient tip can be spring loaded or made of elastomeric material such that when the ball of the valve is under pressure or a back flow condition occurs, the ball valve is not prevented from properly seating in the valve seat to prevent oil leakage.
Another example of the valve opening device is a spring loaded piston mounted to the inner end of the rod with a sliding air retaining seal. The cap disengages the ball by delivering a pulse of compressed air when the piston is rapidly released on opening of the cap.
Therefore, the invention provides significant advantage over the prior art in automatically preventing sticking of the ball of the valve with a simple fail safe device.
In order that the invention may be readily understood, three embodiments of the invention are illustrated by way of example in the accompanying drawings.
Further details of the invention and its advantages will be apparent from the detailed description included below.
In order to automatically dislodge the ball 4 from the valve seat 5 and avoid sticking, the invention includes a rod 7 that extends from the plug 6 towards the inner end of the tube 2. Valve opening means are mounted to the rod 7 for dislodging the ball 4 from the valve seat 5 as follows.
In the first embodiment shown in
In the second embodiment shown in
Although the above description relates to the specific preferred embodiments as presently contemplated by the inventor, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.
Number | Name | Date | Kind |
---|---|---|---|
1756976 | Ehlers | May 1930 | A |
3311984 | Stux et al. | Apr 1967 | A |
3662470 | Sasgen | May 1972 | A |
4124011 | Saito et al. | Nov 1978 | A |
4373548 | Chou | Feb 1983 | A |
4651428 | Allaria et al. | Mar 1987 | A |
H438 | Viksne et al. | Mar 1988 | H |
4991434 | Snow | Feb 1991 | A |
5544419 | Smeltzer | Aug 1996 | A |
6279247 | Neitzel | Aug 2001 | B1 |
Number | Date | Country |
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2275775 | Sep 1994 | GB |
Number | Date | Country | |
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20040065512 A1 | Apr 2004 | US |