Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
2000-06-20
2001-09-18
Banks, Derris H. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
Reexamination Certificate
active
06289770
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The following invention relates in general to hydraulic torque wrenches and more particularly to a safety activation device to prevent the wrench from activating before the wrench is in a safe position.
2. Description of the Prior Art
The petro-chemical industry, as well as industry in general, relies on extensive use of pipes and large valves with bolted or studded flanges. Very large make-up torque of the magnitude of 2,500-5,000 ft-lbs rising to as high as 75,000 ft-lbs are needed to tighten down the nuts on these flanges. Additionally, the break-out torque required may be four or five times the corresponding make-up torque needed for a given flange. Consequently, heavy-duty wrenches, primarily hydraulic torque wrenches, are needed. On such hydraulic torque wrench or power wrench is disclosed in U.S. Pat. No. 4,669,338 to Collins, which is incorporated by reference herein.
FIG. 1
illustrates a power wrench such as disclosed in the '338 Patent wherein the ratcheting box wrench referred to generally as
1
is positioned on a flange-nut
2
in a manner so that the wrench body
3
will contact an adjacent flange-nut
4
. Flange-nut
4
provides the reaction point or base from which the ratcheting box wrench
1
will gain leverage. Wrench
1
will have some type of actuation arm which rotates tool head assembly
8
. In the embodiment shown, the activation arm comprises a piston and cylinder assembly. However, other activation arms such as power screws and the like may be utilized. The hydraulic cylinder
5
is activated and its piston rod (not shown) will extend causing the front cylinder clevis
6
to make contact with the lever arm
7
of the tool head assembly
8
. The front cylinder clevis
6
is connected to the lever arm
7
with a connection pin
9
. As the lever arm
7
is turned by the hydraulic cylinder
5
, the tool read assembly
8
rotates. This rotation is further guided by a tracking arm
10
which is an integral part of the tool head assembly
8
located between the retainer arm
11
and the lever arm
7
. The tracking arm
10
moves within an arcuate channel
12
(shown by hidden lines on
FIG. 1
) within the wrench body
3
. If this tracking arm is properly dimensioned, it will increase the wrench's ability to operate within a confined space since there will be no need to remove and reattach the wrench to the nut during the exercise of a normal ratchet cycle.
It will be understood that when hydraulic fluid flows to cylinder
5
and clevis
6
extends in the direction of force arrow
13
, body
3
will be urged in the direction of force arrow
14
against the reaction point, which is flange-nut
4
in FIG.
1
. Torque is thereby applied to flange nut
2
in the direction indicated by force arrow
15
. Typically, the wrench is activated by an activation switch
16
, which is shown schematically in
FIG. 1
as handheld remote
17
with activation button
45
. While not shown in detail, it is known in the art to have a hydraulic fluid source
18
which will transmit hydraulic fluid to lines
9
a
or
9
b
on cylinder
5
in order to extend clevis
6
or retract it. It is similarly well know in the art how to activate transmission of fluid with a handheld remote
17
. In other words, handheld remote is in operative connection with cylinder
5
.
This configuration of wrench
1
operates safely as long as body
3
is placed against or very close to flange-nut
4
prior to activating wrench
1
(i.e., applying hydraulic pressure to cylinder
5
). As may happen through inattentiveness, a worker may position wrench
1
on a flange-nut
2
as seen in FIG.
2
. If the wrench is a ratchet type as disclosed in the above referenced U.S. Pat. No. 4,669,388, the ratcheting mechanism will allow the user to move body
3
against flange-nut
4
. This is the proper manner of positioning wrench
1
before activating hydraulic cylinder
5
. However, if body
3
is not placed safely against flange-nut
4
and if wrench
1
is activated while in this position, there is no reaction point to restrain the movement of body
3
and body
3
will move toward flange-nut
4
quickly and with great force. If a worker has placed his hand or fingers between flange-nut
4
and body
3
, his hand or fingers may be seriously injured or even amputated. What is needed in the art is a wrench which insures body
3
is safely against a reaction point before fluid will flow to hydraulic cylinder
5
.
OBJECTS AND SUMMARY OF INVENTION
It is an object of this invention to provide a power wrench which is safer to operate than those of the prior art.
It is another object of this invention to provide a power wrench which will not activate before the wrench is properly positioned.
Therefore, the present invention provides a power activated wrench with a safety switch for preventing premature activation. The power activated wrench has a wrench body with a tool head assembly and an activation arm for applying torque to the tool head assembly. An activation switch is in operative connection to the activation arm. A safety switch housing is connected to the wrench body and a contact surface connected to the safety switch housing. The proximate connection of the contact surface with a reaction point enables the activation switch.
REFERENCES:
patent: 418337 (1889-12-01), Kors
patent: 1534334 (1925-04-01), Stutsman
patent: 1950704 (1934-03-01), Thomson
patent: 2242954 (1941-05-01), Ingwer
patent: 2429929 (1947-10-01), Fisher
patent: 2517062 (1950-08-01), Vosper
patent: 2615682 (1952-12-01), Stone
patent: 2634518 (1953-04-01), Merz
patent: 2712256 (1955-07-01), Fish
patent: 2837177 (1958-06-01), Edge et al.
patent: 2855613 (1958-10-01), Kostka
patent: 3031699 (1962-05-01), Fleury
patent: 3683686 (1972-08-01), Sergan
patent: 3706244 (1972-12-01), Wilmeth
patent: 3745858 (1973-07-01), Biach
patent: 3930776 (1976-01-01), Keller
patent: 3995828 (1976-12-01), Orban
patent: 4027560 (1977-06-01), Parker
patent: 4027561 (1977-06-01), Junkers
patent: 4028868 (1977-06-01), Zehrung, Jr.
patent: 4060137 (1977-11-01), Bickford et al.
patent: 4091890 (1978-05-01), Wilmeth et al.
patent: 4095917 (1978-06-01), Wesner
patent: 4141262 (1979-02-01), Smith
patent: 4155278 (1979-05-01), Estok
patent: 4180144 (1979-12-01), Adams
patent: 4201099 (1980-05-01), Junkers
patent: 4201503 (1980-05-01), Nannen
patent: 4211150 (1980-07-01), Framberg
patent: 4260183 (1981-04-01), Krupp
patent: 4275620 (1981-06-01), Collins
patent: 4308767 (1982-01-01), Wilmeth
patent: 4325274 (1982-04-01), Martelee
patent: 4333365 (1982-06-01), Perry
patent: 4336727 (1982-06-01), Junkers
patent: 4385533 (1983-05-01), Collins
patent: 4408363 (1983-10-01), Doree
patent: 4414701 (1983-11-01), Johnson
patent: 4448096 (1984-05-01), Collins
patent: 4513645 (1985-04-01), Grabovac et al.
patent: 4607546 (1986-08-01), Wagner
patent: 4794825 (1989-01-01), Schmoyer
patent: 5152196 (1992-10-01), Garrett
patent: 671630 (1929-12-01), None
patent: 972449 (1963-10-01), None
patent: 579132 (1975-12-01), None
patent: 2749857 (1977-11-01), None
Banks Derris H.
Roy, Kiesel, Keegan & DeNicola
Thomas David B
LandOfFree
Power wrench safety switch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Power wrench safety switch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power wrench safety switch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2480046