Electric heating – Heating devices – Resistive element: igniter type
Reexamination Certificate
2000-03-31
2001-06-26
Jeffery, John A. (Department: 3742)
Electric heating
Heating devices
Resistive element: igniter type
C219S541000, C219S544000, C123S14500A, C338S322000
Reexamination Certificate
active
06252200
ABSTRACT:
FIELD OF THE INVENTION
The subject matter of the invention is a process for sealing the terminal-side end area of the glow tube of a glow plug and a corresponding glow plug.
BACKGROUND OF THE INVENTION
Reducing the diameter of the terminal-side end area of the glow tube of a glow plug by rotary swaging is known, in which a central, solid and sealing connection of the end of the glow tube to the projecting inner pole of the glow plug will be achieved without damage of the gasket which is located in this area.
To do this, rotary swaging machines which are also called hammering or reducing machines are used which reduce the outside diameter in an advance process by forming under compressive a conditions with a relatively high speed working pulse sequence and thus close the glow tube filled with the inner pole and insulator via the gasket.
Rotary swaging machines use tools which radially oscillate via rams with high working frequency form the workpiece located in the center of the tools accordingly. In doing so then a high-speed, brief forming stroke of the tool is transmitted to the workpiece located in the center when a ram pair passes under the roller pair. Between the strokes the rams and tools are opened by centrifugal force and the workpiece continues to be inserted axially. The tolerances which can be achieved in rotary swaging in a cold working process are +/−0.01 mm.
The original outside diameter of the glow tube is reduced in a certain length to a certain amount which is conventionally not yet the final amount, and thus sits stationary on the inner pole, sealing element and insulating material. The connection which has been produced hereby must be of a bulk nature for the next working process which relates to reduction of the heating rod to its final size.
The high noise evolution which necessitates the noise control booths is disadvantageous in the rotary swaging process and rotary swaging devices known from the prior art. The noise evolution is caused by the necessary high ram frequency which is caused by the low forming per stroke of the rotary swaging machine. The friction portion of the workpieces in the tools must be great to prevent the workpiece from being expelled from the tools opposite the feed direction. The noise arises especially at the locations at which the rams hit the rollers, tools hit the workpiece, and in idle, the tool halves of the rotary swaging devices hit one another.
In addition, due to the large radial and axial loading of the end area to be machined in the glow tube there is the danger of damage of the sealing elements located in it, for example by overstretching.
SUMMARY OF THE INVENTION
As experience shows, a central location of the inner pole cannot be set 100% reliably so that in this way undesirable failures occurs. Since the glow tube turns concomitantly in the tool, there is the danger that it will be milled in adjacent areas. Disadvantageously high investment costs, large space requirement and disproportional tool wear are also added, therefore the process of rotary swaging known beforehand is overdimensioned as a means for sealing of the glow tube end area; likewise it has been shown that the indicated production tolerances are not necessary here.
The object of the invention is to make available a process, while surmounting the indicated defects, such that it is tailored to the requirements of sealing of the indicated glow tube end area and can be incorporated to mass production of glow plugs, and allows further processing in mass production. In particular damage to the gasket material will be avoided to prevent harmful penetration of oxygen. Finally, glow plugs will be made available in which the sealing of the terminal-side end area of a glow plug tube meets the necessary requirements for this sealing.
The object of the invention is achieved by the process as claimed in claim
1
with the advantageous embodiments as claimed in claims
2
to
5
, and by the glow plug as claimed in claim
6
with the following preferred embodiments as claimed in claim
7
.
REFERENCES:
patent: 4211204 (1980-07-01), Glauner et al.
patent: 4221452 (1980-09-01), Remington
patent: 4312120 (1982-01-01), Comer
patent: 4477717 (1984-10-01), Walton
patent: 4733053 (1988-03-01), Mueller
patent: 5589091 (1996-12-01), Muller
patent: 5783801 (1998-07-01), Riti et al.
patent: 196 30 402 (1998-01-01), None
patent: 40 997 (1981-12-01), None
patent: 989 370 (2000-03-01), None
patent: 10-185192 (1998-07-01), None
Hain Rainer
Heinz Rudi
Beru AG
Jeffery John A.
Nixon & Peabody LLP
Safran David S.
LandOfFree
Process for sealing the terminal-side end area of the glow... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for sealing the terminal-side end area of the glow..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for sealing the terminal-side end area of the glow... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499699