Measuring and testing – Dynamometers – Responsive to torque
Reexamination Certificate
2002-09-12
2004-09-21
Lefkowitz, Edward (Department: 2855)
Measuring and testing
Dynamometers
Responsive to torque
C081S052000
Reexamination Certificate
active
06792816
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a bit adapter for a torque detector that enables one to simply check and maintain torque accuracy by coupling a rotary fastening tool to the torque detector, in order to maintain the fastening (of screws, bolts, and the like) at a given torque value when using a rotary fastening tool (e.g., electric driver, air driver) in an assembly line for various industrial products, and the like.
Conventionally, it always has been important to tighten to a specific torque value when assembling various industrial products, and the like, and tightening screws, bolts, and the like, by using a rotary fastening tool (e.g., electric driver, air driver). As a result, for the aforesaid rotary fastening tool, in order to always maintain the tightening torque at the specified value, the reference torque value must be preset, and it is essential to utilize a torque control operation that allows the rotary fastening tool's torque to be adjusted by means of the appropriate torque detector.
Therefore, as the aforesaid rotary fastening tool's torque adjustment means, conventionally known devices are configured so that it is possible to set the tightening torque value with high precision, by combining a coil spring and a clutch mechanism, for example, and by then adjusting the compression state of this coil spring. That is, this type of torque adjustment means is configured based on the theory of determining the balance point between the coil spring's spring constant and the rotary fastening tool's turning force applied in the axial direction.
However, the inventor obtained Japanese Patent No. 1456555 (Japanese Patent Application Publication No. 63-4130), after developing, as a means of smoothly controlling the torque of the aforementioned rotary fastening tool, a device that is equipped with liquid-crystal display that allows the user to instantaneously digitally display and check the measured torque value of the rotary fastening tool, and that is equipped with a torque detector configured so as to enable the detection of the torque value set in the aforesaid rotary fastening tool, via a bit adapter (i.e., rotational inertia force damper) consisting of a coupling means for transmitting the rotary tightening force by coupling the driver bit of the rotary fastening tool.
The invention of the aforesaid patent is characterized in that one end of a threaded shaft screws, in a freely adjustable state, into a shaft pedestal with a screw hole; a locking part that detachably engages the output shaft of the rotary fastening tool is provided at the other end of the aforesaid shaft; a flange part is provided on a part of the aforesaid shaft, adjacently to the aforesaid locking part; a thrust bearing and a coil spring are interposed between this flange part and the aforesaid shaft pedestal; thereby configuring a bit adapter (i.e., rotational inertia force damper) that functions as a means of damping the rotational inertia force of the output shaft of the aforesaid rotary fastening tool.
FIGS. 6 and 7
show the general configuration of the aforementioned conventional bit adapter (i.e., rotational inertia force damper). In
FIGS. 6 and 7
, the bit adapter
10
is composed basically of a shaft pedestal
13
with a screw hole equipped integrally with a square step
12
that fits tightly into the special opening-shaped part formed in the bit coupling
22
provided in the torque detector
20
; the threaded shaft
14
configured such that one end screws, in a freely movable state, into the screw hole
13
a
provided in the center of this pedestal
13
; the helical compression spring
15
that is disposed by inserting it concentrically around this shaft
14
so as to enclose it; and the flange part
16
that is positioned opposite the pedestal
13
, relative to the aforesaid shaft
14
, and that, together with the aforesaid pedestal
13
, tightly holds the aforesaid helical compression spring
15
.
At the other end of the aforesaid shaft
14
is provided the locking part
14
a
that has a chuckable shape formed at the end of aforesaid bit, and so forth, like the detachably coupled driver bit, and so forth, relative to the tip of the output shaft
24
of a rotary fastening tool (e.g., an electric driver, an air driver, another nut setter), which is the measurement target. The bearing holder
17
, which is formed so as to enclose the aforesaid flange part
16
, is disposed relative to the shaft
14
formed in this manner. That is, this bearing holder
17
fits with play around the aforesaid shaft
14
; it and the aforesaid flange part
16
encloses and holds appropriately the washer
18
and the thrust bearing
19
; and it is disposed so as to abut and freely slide against the aforesaid flange part
16
. This is configured so that the helical compression spring
15
, which is inserted so as to enclose the aforesaid shaft
14
, is resiliently pressure-contacted and held at both ends, between the aforesaid bearing holder
17
and the aforesaid pedestal
13
(see FIG.
7
).
Measurement preparations are completed for the bit adapter
10
configured thus by engaging the locking part
14
a
of the shaft
14
in the output shaft
24
of the rotary fastening tool, which is the measurement target, and by then tightly fitting the square step
12
formed integrally in the shaft pedestal
13
into the bit coupling
22
of the torque detector
20
(see FIG.
6
).
Next, when the rotary fastening tool is activated, the output shaft
24
and the shaft
14
rotate, and one end of the shaft
14
screws into the screw hole
13
a
provided in the center of the pedestal
13
. In this manner, the helical compression spring
15
is compressed axially between the bearing holder
17
and the pedestal
13
, and when it reaches its compression limit, which corresponds to the strength of the rotational torque exerted on the shaft
14
, the shaft
14
loses its ability to screw further into the screw hole
13
a
of the pedestal
13
.
In this manner, while the rotational torque obtained at the output shaft
24
of the aforesaid rotary fastening tool is transmitted, via the bit adapter
10
, to the detection part (not shown) of the torque detector
20
, the rotational inertia force is absorbed by the plastic deformation resulting from the elastic force of the helical compression spring
15
, so it is possible to transmit only the net rotational torque. As a result, at the detection part of the torque detector
20
, the rotational inertia force that accumulated in the output shaft
24
of the rotary fastening tool is absorbed and relaxed by the elastic force of the helical compression spring
15
, so it is possible to reproduce a state similar to that during an actual rotary fastening operation and to measure the accurate torque value corresponding only to the net rotational torque.
However, the conventional bit adapter for a torque detector configured as aforementioned has the following problems, among others, that must be solved: During preparations to measure the set torque value in order to fasten the screw, and the like, of a rotary fastening tool, the work required to couple the tip of the output shaft
24
of the rotary fastening tool to the aforesaid bit adapter for a torque detector
10
and then to tightly fit this into the bit coupling
22
of the torque detector
20
is somewhat cumbersome and requires operator skill.
Also, during the torque value measurement operation in the aforementioned conventional bit adapter for a torque detector, in order to forcibly screw the threaded shaft
14
into the screw hole
13
a
of the shaft pedestal
13
in opposition to the elastic force of the helical compression spring
15
, excessive stress is exerted on the aforesaid shaft
14
, so there is a risk of instantaneous breakage of the shaft
14
as the result of numerous operations.
SUMMARY OF THE INVENTION
So, after assiduously researching and studying the problems of the aforesaid conventional bit adapters for a torque detector, the inventor ascertained that it is possible to
Jordan and Hamburg LLP
Lefkowitz Edward
Miller Takisha
LandOfFree
Bit adapter for torque detector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bit adapter for torque detector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bit adapter for torque detector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3262986