Note: Descriptions are shown in the official language in which they were submitted.
L3~7~;~
PR~SSURE GAUGE WITH ADD-ON WRENCH FLATS
-
Background of the Invention
1. The field of art to which the invention pertains
includes the art of measuring and testing as directed to
fluid pressure gauges.
2. Gauge instruments, and particularly pressure gauges
or the like, have been widely used and are commercially
available from a variety of manufacturing sources. Being
that such pressure gauges enjoy very extensive commercial
and industrial use, they are supplied by a plurality of
manufacturers/ and are regarded as high production items.
Because they are sold in very price-conscious competition,
each manufacturer instinctively strives to reduce product
costs by improvements, however marginal, which reduce labor
and/or materials that can contribute to cost savings in the
end product.
All pressure gauges include a socket by which the gauge
can be connected to a source of fluid pressure to be measured.
In a typical construction, the gauge socket may be formed of
bar stock of square or hexagonal cross-section whereby the
unmachined surface can serve as wrench flats during install-
ation and removal of the gauge. Despite the foregoing
virtue of the square or hex section, it is highly desirable,
and indeed preferable, -to make the socket from round stock,
i. e., of circular cross-section. Generally speaking, the
advantages of the latter are threefold, namely: a) for a
given size, round stock is the most economical bar shape;
b) round stock geometry facilitates joining of the case and
socket when welding or brazing is the method of choice; and
c) a round interface between socket and case facilitates
sealing whether it be a metallurgical bond or mechanical
seal.
~2~3'75Z
Whell the socke-t is fabricated from round stock,
i-t is common practice to mill or broach two parallel flats
clS wrenching surfaces. Thls metal removal, of course, reduces
the distance across the wrench flats to a dimension sub-
stantially less than basic stock diameter with a dimension
across the wrench flats less -than the major diameter of
the socke-t thread. As a consequence, the amount of torque
that can be applied, for example to a 7/8-inch diameter
socket with 5/8-inch parallel flats without s-trippiny the
wrench flats is reduced substan-tially compared to other
sockets from larger square or hex stock. While the machined,
parallel flats generally offer sufficient strenyth for makiny
up the process connec-tion, some code standards, such as
the German DIN standard 16288, require that the wrenching
surface be square or hexagonal and of a size larger than
the ma~or thread diameter of the socket.
Needless to say, utilizing oversize~ bar stock
of s~uare or hexagonal cross section merely to accommoda-te
the foregoing standard not only constitutes a waste in both
labor and material, but at the same time it defea-ts the
noted virtues for the use of round stock mentioned ab~ve.
Despiterecognition of the problem, a solution therefor has
not heretofore been known.
The present inven-tion resides in a pressure
gauge including a pressure sensitive element, a tubular
socket assembly to the pressure sensitive element and adapted
for connecting the pressure sensitive element to a source
of fluid pressure, and a case for housing the pressure sensitive
element and including an aperture closely sizecl to accommodate
the socket extending therethrough. Wrench flats are added
to the peripheral surface of the socket and have a ma~imum
dimension in the plane of the flats greater than the maximum
pass through dimension of the case aperture.
More specifically, the present invention relates
to a socket construction for pressure gaucJes which is able
-to meet the DIN wrench flat standard, while continuillg to
"
mab/
,~
3L;~'75'~
be formed of more economically advantageous round stock~
This is achieved in accordance with the invention by forminy
-the socket of round stock construction as before. After
assembling the operating gauge components and socket to
the gauge case, wrench fla-ts of required size are added
on such as by welding to the socket periphery. By this
means, all the virtures of round stock construction are
readily retained while any size wrench surface can be merely
added to meet code requirements.
It is therefore an object of the invention to
eEfect a novel socket cons-truction for a pressure gauge
having oversized wrench flats on a round stock socket
construction.
. ~
~ - 2a -
.
L~7S~
Brief Description of the Drawings
Fig. 1 is a fragmentary front elevation of a prior art
pressure gauge with the components in pre-assembly relation
to the case housing;
Fig. 2 is a fragmentary view of the post-assembly
relation of the prior art pressure gauge of Fig. l;
Fig. 3 is a sectional elevation generally corresponding
to Fig. 2 of a socket construction in accordance with the
invention;
Fig. 4 is a sectional view as seen substantially along
the lines 4-4 of Fig. 3; and
Fig. 5 is a fragmentary sectional elevation for an
alternative embodiment to Fig. 3.
Referring now to the prior art gauge constructions of
Figs. 1 and 2, the pressure gauge thereof may, for example,
comprise a type disclosed in U.S. patent 4,361,046. Briefly,
pressure gauge 10 includes a floating amplifier 12 supported
on the free end 14 of a coiled Bourdon tube 16. Fluid
pressure represented by arrow 18 is received inward of round
stock socket 19 that includes mounting threads 20 and a longi-
tudinal bore 25. Socket 19 is weld connected at 21 to the
fixed end of Bourdon tube 16 wherefrom fluid pressure 18 is
conducted inwardly to effect displacement of tube end 14 in
a well known manner.
Amplifier 12 floats conjointly with tube end 14 for
operating segment gear 32 to effectively drive a pinion 23
on shaft 22 supporting a pointer 24. Arcuate displacement
of the pointer via rotation of shaft 22 reflects values of
pressure as represented by graduations 26 on dial face 28
supported in case 29. Because it is most difficult to
effect weld 21 with the components arranged within the
case, it is customary for the operating components and
socket to be preassembled as shown in Fig. 1. Thereafter,
socket 19 is passed downward (or rearward for a back connected
gauge) through the case socket aperture 34 in the direction of
arrow 36 until arranged in the manner of Fig. 2. Desirably,
aperture 34 is then sealed about the received socket as,
for example, by weld 38.
Referring now to Figs.3 and 4,socket 19 for purposes hereof
includes an annular concentric surface 40 at a longitudinally
375Z
intermediate socket location between shoulders 41 and 43.
The diameter of surface 40 is only slightly greater than
the O.D. of thread 20. With the socket in place in case
aperture 34, one-piece sleeve-like wrench flats 42 having
an I.D. 45 matched for a slip fit onto surface 40, is
placed thereon and then secured to the socket by means of
weld 44. This results in oversized wrench flats42 of
dimension A which, pursuant to DIN standard 16288 published
April 1972, are required to be as follows:
Socket 5ize - Diameter Dimension ~ - mm
Square Flats Hex Flats
1/4 inch 14 17
1/2 inch 22 27
Typically, this will effect a diametral oversize dimension
B on the order of about one millimeter.
The alternative embodiment of Fig. 5 differs only in
the manner by which socket 19 is secured to case 29 by angle
bracket 48 rather than a weld 38 as in the previous embodi-
ment and secured to case 29 by means of a screw 50. An
o-ring gasket 46 provides a pressure-tight seal between the
case and socket at aperture 34.
sy the above description there has been disclosed a novel
construction for a pressure gauge enabling wrench flat
requirements of DIN standards to be met on a pressure gauge
socket while retaining the attributes of forming the socket
from round stock. While weld 44 has been mentioned as the
preferred approach to joining the wrench flats 42 to socket
19, this, of course, requires weldably compatible metals
to effect. Consequently, brazing, bonding, etc. where suit-
able could be just as readily utilized for that purpose.By means, therefore,of a simple yet effective approach to the
problem, a ready solution has been achieved without incurring
the cost penalties of an obvious approach thereto.
Since many changes could be made in the above construc-
tion, and many apparently widely different embodiments ofthis invention could be made without departing from the
scope thereof, it is intended that all matter contained in
the drawings and specification shall be interpreted as
illustrative and not in a limiting sense.
