Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to pneumatically powered hand-
held torque wrenches having means for measuring and displayiDg
the amount of torque applied to a fastener.
The structure and operational characteris-tics of the
wrench per se are known in the art, for example, as disclosed in
t~l 5t~ 5
~patent 3,621,738, granted to OOVo Northcutt on November 23, 1971.
The present invention concerns the addition of a torque measuring
and display means on a wrench of the type disclosed in said patent.
A feature of this invention resides in the fact that af-
ter a fastener set-ting operation, the torque reading will be main-
tained until reset by the operator.
Another feature of the invention is that the tool oper-
ator can see the value of torque as it is being developed during
tool operation.
Still another feature is that the torque developed by
the tool can be measured in a forward as well as a reverse dir-
ection, and with or without pressuri~ed medium being supplied to
the tool.
A~other feature o:E the tool of the invention is use of
a simple torque tube to provide resistance force to tool handle
flexure, which torque tube also serves as a pressure medium con-
duit for the tool motor.
A further feature of the tool is simplicity in struc-
tural detail and operational characteristics, as well as a tool
which will provide accurate torque read-out and long, trouble-free
serviceO
The present invention provides in a torque read-out
pneumatically powered hand-held tool for setting fasteners, the
tool having in axial alignment a handle portion, a motor portion
and a work engaging portion, an improvement comprising a torque
read-out means including a rotatable torque indicating dial arranged
on the handle portion, and a linkage means enclosed in the handle
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33
portion, one end of the linkage means arranged in operative en-
gagement with the dial, the other end of the linkage means being
arranged for movement responsive to change in axial alignment
between the motor portion and the handle portion resulting from
torque developed on a fastener by the tool at the work engaging
portion whereby the dial is r,ota-ted to indicate the torqueO
Other features and advantages of the invention over
known prior art devices, will be evident from the invention dis-
closure which follows:
In drawings which illustrate embodiments of the inven-
tion:
Fig. 1 is a top view of a wrench embodying the invention;
Figo 2 is an enlarged partial section as seen from line
2-2 in Figo 1,
Fig~ 3 is a sectioD view as seen from line 3-3 in Fig. 2;
Fig. 4 is a section view as seen from line 4-~ in Fig, 2;
Fig. 5 is a section view as seen from line 5-5 in Fig. 2;
and
Fig. 6 is a top view of a torque transmitting linkage
member arrangement as used in the tool of Figo lo
Referring now to the drawings, Fig. 1 illustrates a tool
10 embodying the principles of the invention, which tool includes
a handl~ portion 12, a motor portion 14, and a work engaging por- ~'
tion 16, all portions normally being in axial alignment in non-
operative tool conditionO The portions 14 and 16 include structural
detail which is known in -the prior art, such as in patent 3,621,738, ;
and no detail description is believed necessary for a clear under-
standing of the subject invention. The work engaging portion is
affixed to the motor portion 14, by bolts 18, and includes a
reversable ratchet mechanism 20, which drives a shank 22 for ro-
tation of a fastener (not sho~)O The ratchet mechaDism 20 is
operated by a crankshaft 24, the end of which is eccentrically '~
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arranged in a drive bushing 26 having the form of a ball. The
crankshaft is rotated by a sliding vane motor arranged in the
motor portion 140
The handle portion 12 is in the form of a cylindrical
housing 28, one end of which is enclosed, the other end being open
and mounted upon a rear extension 30 of the motor portion and
secured thereon by two diametrically arranged pins 320 Slight
clearance between the housing and the rear extension is provided
to allow a change in axial alignment between said parts when rota-
ting force is applied to the handle portionO If the housing ismade of material sufficiently flexible under the manual force e~-
erted upon the handle portion in tool operation, such inter-fit
clearance can be dispensed witho A torque tube 34 is enclosed in
the handle portion 12, one end of the tube being mounted in the
rear extension 30, the other end being mounted in a solid part 36
forming the enclosed end of the cylinder 28. Pressure medium i.e.,
compressed air, is admitted to the tool by means of hose coupling
38, and air flow control effected by a throttle valve 40 movable
by a handle 42 pivotally secured to the handle portion 120 The
valve is spring biased toward sea-ted positionO Air flowing past
the throttle valve 40 enters the torque tube 34 and leaves at the
forward end after which it powers the motor and is exhausted to
atmosphere, in well known mannerO
~ truncated platform 44 is secured at one end to the
rear extension 30 by cap screws 46, which platform extends in
paralle].ed relation to the torque tube 34, as best seen in Fig. 2.
A gear platform 48 is mounted atop the platform 44, and is fixed
for rotary movement about a pivot pin 50 secured to the platform
44. One end of the gear platform 48 has a gear toothed portion
52, while the other end has a pin 54, the free end o* which is
arranged to extend into a longitudi~al groove 56 formed on the
inner surface of handle cylinder 28~ ~he free end of the gear
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platform may be arranged in contact with the torque tube 34 to
provide platform rotation during fastener torquing, as is evident
to one skilled in the artO
An elongated pin 58 is affixed to the platform 44 and
projects upwardly therefromO A driver gear 60 is arranged upon
the pin 58, the lower portion of the gear 60 being in working
engagement with gear platform tooth portion 52, while the upper
part supports a dial platform 62. The handle portion 12 is formed
with a cylindrical portion 64, the axis of which coincides with
the axis of elongated pin 58. A bezel.66, supporting a lens 68,
is secured to the cylindrical portion 64 at the upper extremity
thereof, and is arranged to be manually rotatedO A reverse button
70 is mounted upon the lens 68, the lower portion of the button
having a pointer 72 affixed thereto. The dial platform 62 supports
a dial 74 having indicia 76 representi.ng torque read-out values,
as best seen in ~igo lo Note that the torque values are symmet-
rically arranged on each side of zero value from 10 to 70 ft~-lbso
of torque indication.
Extending from the dial platform and through a hole in
the dial 74, is a small projection 78, which is arranged to serve
as an abutment against the short end of the pointer 72, which is
bent, as shown in Figo 2, A small pin 80 is affixed to the inner
surface of the bezel 66 and pro~ects over the dial 74, however, the
long end of the pointer 72 is free to move past the pin 80 without
interferenceO A disc spring 82 is secured to the lower part of
the revers.e button 70, and functions to hold the pointer 72 in
position until reset by the operator after a torque read-out
operation.
When manual force is applied to the tool handle, the ;
crankshaft 24 is rotated to a dead position, which is in line
with the direction of the applied forceO This causes manual torque
load to be taken by the tool handle and flex the tube 34 and
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handle portion 12 Such action results in movement of the gear
platform 48 about pivot pin 50, and rotation of the dial platform
62 by reason of engagement of the driver gear 60 and platform
toothed portion 520 As a result, the dial 74 is rotated, and
when torquing effort is terminated, the pointer 72 remains at
maximum torque value achievedO
It is seen that when torque load is applied to the tool,
rotary movement of dial 74 causes the small pin 80 to indicate
torque value on one set of indicia 76, and when torque load is
released, the pointer 72 indicates torque on the opposite set of
indicia 76. In such manner, the tool operator can observe the
torque value being developed, and has a pointer indication of such
torque value after the torque load is releasedO Since the tool is
reversible, such torquing feature o~ the tool is obtained in either
direction of rotation of a fastener being worked upon~
In operation, assuming that the tool is in operative
position to run up and set a fastener, with the pointer 72 being
set at "0" torque reading. Compressed air is admitted to the
motor when the throttle lever ~2 is depressed, and the fastener is
rotated until the motor stalls as the fastener is seatedO The
pointer 72 is rotated to indicate the value of stall -torque by
reason of the rotary movement of the dial platform 62, said
pointer rotation being ef~ected by the projec-tion 78 engaging the
bent end of the poi~ter.
The operator may then increase applied torque by e~er-
ting manual force upon the tool handle until desired developed
torque is achieved, as shown by the pointer 72 indicating the
torque value on the dial 740 Upon release of force upon the tool
handle, the pointer remains in torque read-out position until
reset by the operator.
It is apprecia-ted that the tool will ~unction equally
well, as far as torque read-out is concerned, with or without use
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383
o~ compresseA air, that is, manual force alone produces torque
read-out values within the tool range capacityO
While an embodiment of the invention has been illustrated
and described in detail, it is to be expressly understood that
the invention is not limited theretoO Various changes in form,
design, or arrangement may be made in its parts without departing
~rom the spirit and scope of the invention; it is my intention,
therefore, to claim the invention not only as shown and described,
but also in all such forms and modifications thereof as might be
reasonably construed to be within the spirit o~ the invention and
the sccpe of the appended claimsO
