Abrasive tool making process – material – or composition – With carbohydrate or reaction product thereof
Patent
1990-04-12
1992-07-28
Meislin, D. S.
Abrasive tool making process, material, or composition
With carbohydrate or reaction product thereof
51181NT, 51241VS, 51 3, B24B 1504
Patent
active
051331543
DESCRIPTION:
BRIEF SUMMARY
The invention relates to an apparatus for use in grinding the needle tip and seat in the needle housing of a fuel valve. The invention also relates to a fixture for fixing the needle housing when using the new apparatus.
A needle housing in a fuel valve has a needle bore for receiving a needle. Uppermost or at the top the needle housing has a ground surface from which an inclined bore leads down to a ring-shaped space located at the inner end of the needle bore. At this location there is provided a seat intended for sealing against the needle tip. The sealing face of the needle tip against this seat should be on the largest diameter of the needle tip and be as narrow as possible in order to obtain a good atomization of the fuel which is supplied through the inclined bore as mentioned above. To obtain this desired narrow sealing face the needle tip and seat must be ground with an angular difference of 0.5.degree.-1.degree.. The invention has been developed in connection with the desire and need of being able to perform this grinding in a rational and automated way, and in this connection there is according to the invention provided an apparatus which is characterized in that it comprises a grinding pin and a holder for the grinding pin, the holder being shaped and dimensioned to be guidingly received in the needle bore of the needle housing and the grinding pin having a first conical end adapted for the seat and a second hollow conical end adapted for the needle tip.
Preferably the grinding pin is made for single use, for example from hardened steel.
For the purpose of grinding the needle, the holder is advantageously provided with a split ring placed in a circumferential groove, the ring having a diameter a little larger than the needle bore, with an axial stopper pin in the holder entering the opening of the split ring, the grinding pin and holder having cooperating elements for locking with a view towards relative rotation.
Because the split ring has a diameter a little larger than the needle bore, it will attain a slight tensioning against the wall of the needle bore when the holder is inserted into the needle bore. Before the holder is put into the needle bore, the grinding pin is placed in the holder whereby the mentioned cooperating elements are caused to interlock. The holder with the grinding pin is inserted into the needle bore until the conical end of the grinding pin, which protrudes from the holder, bears against the seat in the needle housing. The needle housing is fixed in a suitable way in a grinding machine, and the needle which is to be ground is inserted into the needle bore such that the needle tip enters the hollow conical end of the grinding pin. Then, when the needle is brought into rotation, the holder firstly will try to follow the rotational movement. The stopper pin mentioned, however, will bear against one of the ends at the opening of the split ring and thus act on the split ring to expand it, whereby the holder will be locked in the needle bore. This will also lock the grinding pin.
Advantageously the ends at the opening of the split ring can be tapered such that they converge in an outward radial direction, thus to form inclined flanks for cooperation with the stopper pin.
The mentioned cooperating elements may advantageously comprise a locking pin and a locking groove. The locking groove may advantageously have the shape of a bayonet groove.
Fuel valves with a small difference between the diameter of the needle bore and the largest seat diameter will require an embodiment of the grinding pin as two separate parts to attain a step-down, such that there is attained room for the expansion ring and the stopper pin.
Advantageously there may in a circumferential groove in the holder be mounted an O-ring. This O-ring contributes to the beginning locking of the holder and furthermore also serves for sealing, a function whose purpose will be explained in further detail below in connection with the new fixture.
As mentioned the invention also relates to a fixture for fixing the needle
REFERENCES:
patent: 1183855 (1916-05-01), Clarkson
patent: 1993844 (1935-03-01), Karnath
patent: 3021651 (1962-02-01), Fuller et al.
patent: 3388232 (1968-06-01), Dreisin
patent: 3813635 (1965-05-01), Spirounis
patent: 4687142 (1987-08-01), Sasao et al.
LandOfFree
Apparatus and fixture for use in grinding the needle tip and the does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and fixture for use in grinding the needle tip and the, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and fixture for use in grinding the needle tip and the will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1680797