U.S. patent number 3,661,187 [Application Number 04/870,190] was granted by the patent office on 1972-05-09 for strap-tensioning and severing tool.
This patent grant is currently assigned to Panduit Corp.. Invention is credited to Jack E. Caveney, Roy A. Moody.
United States Patent |
3,661,187 |
Caveney , et al. |
May 9, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
STRAP-TENSIONING AND SEVERING TOOL
Abstract
There is disclosed a hand tool for tensioning and severing
straps of the type used in binding bundles of wires into cables,
such straps including a connector adjacent one end thereof and the
other end being free and adapted to be wrapped around the bundle to
be bound and thereafter slid through the connector in a tightening
movement, the tensioning and severing tool has a pair of jaws, one
of which engages the connector and the other of which engages the
free strap and extending beyond the connector, drive mechanism for
tensioning the strap by moving the jaws apart and for thereafter
actuating a strap-severing blade after the application of a
predetermined force between the jaws, the tool of the present
invention including mechanism for applying a restraining force upon
the severing blade drive mechanism of a character which will
prevent blade severing movement until the aforementioned
predetermined tension is reached in the strap, after which means is
provided that serves substantially instantaneously to relieve or
reduce the restraining force in the blade drive mechanism, whereby
the blade drive mechanism immediately and quickly actuates the
blade to sever the strap; a combined trigger-type drive mechanism
is provided which ensures that the same tension is produced in the
strap at the cut-off no matter how the handle actuating the drive
mechanism is gripped by the user; the blade drive mechanism is such
that immediately upon cut-off, and before the blade actually cuts
through the entire strap, the drive tension is released so that the
blade never strikes the anvil or backup for the strap; finally, a
novel adjustment mechanism is provided for adjusting the
predetermined tension at which cut-off of the free strap end is
effective.
Inventors: |
Caveney; Jack E. (Chicago,
IL), Moody; Roy A. (Flossmoor, IL) |
Assignee: |
Panduit Corp. (Tinley Park,
IL)
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Family
ID: |
25354929 |
Appl.
No.: |
04/870,190 |
Filed: |
July 28, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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772441 |
Oct 21, 1968 |
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474563 |
Jul 26, 1965 |
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Current U.S.
Class: |
140/123.6;
D8/44 |
Current CPC
Class: |
B65B
13/027 (20130101) |
Current International
Class: |
B65B
13/00 (20060101); B65B 13/02 (20060101); B21f
009/00 (); B21f 011/00 (); B21f 021/00 () |
Field of
Search: |
;81/9.3 ;100/29,32,33
;140/93,93.2,93.4,123,123.5,123.6 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lanham; Charles W.
Assistant Examiner: Combs; E. M.
Parent Case Text
This application is a continuation of Ser. No. 772,441, filed Oct.
21, 1968, which was a continuation of Ser. No. 474,563, filed July
26, 1965, now both abandoned.
Claims
What is claimed is:
1. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, linkage operatively connected to said
gripper and said blade, an actuator operatively connected to said
linkage, said linkage having a strap-tensioning mode wherein the
force exerted by said actuator through said linkage is applied to
said gripper for moving said gripper in a strap-tensioning
direction and having a strap-severing mode wherein force exerted by
said actuator through said linkage is applied to said blade for
moving said blade in a strap-severing direction, and restraining
means for holding said linkage in said strap-tensioning mode until
a predetermined tension is reached in the length of the strap
between the first and second points thereon whereupon said linkage
is shifted into said strap-severing mode thereof, means mounting
said actuator for movement thereof between a rest position and a
fully-actuated position along a predetermined regular path with
respect to said abutment, the predetermined path of travel of said
actuator during said strap-tensioning mode of said linkage being
identical to the predetermined path of travel of said actuator
during said strap-severing mode of said linkage thereby to provide
a single predetermined path of travel for said actuator between
said rest position and said fully actuated position thereof,
whereby said restraining means is overcome when a predetermined
tension is produced in the portion of the strap between the first
and second points thereon thereafter to shift said linkage from the
strap-tensioning mode thereof to the strap-severing mode thereof to
cause actuation of said blade to effect severing of the strap, said
predetermined tension being independent of the point at which the
operator manually engages said actuator to apply the operating
forces thereto.
2. The binder strap tensioning and severing tool set forth in claim
1, wherein the predetermined path of said actuator from said rest
position to said fully-actuated position is a pivotal path about a
point fixed with respect to said abutment.
3. The binder strap tensioning and severing tool set forth in claim
1, wherein said restraining means is adjustable so as to adjust the
predetermined tension in the portion of the strap between the first
and second points thereon causing actuation of said blade to effect
severing of the strap.
4. The binder strap tensioning and severing tool set forth in claim
1, and further comprising releasable interconnecting means between
said linkage and said restraining means, said releasable
interconnecting means being responsive to the predetermined tension
in the portion of the strap between the first and second points
thereon effectively to disconnect said restraining means from said
linkage to shift said linkage into said strap-severing mode.
5. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said abutment and said gripper for movement relative
to each other in a strap-tensioning direction to tension the
portion of the strap between the first and second points thereon, a
blade for severing the strap along the portion thereof between the
first and second points thereon, a common linkage interconnecting
said gripper and said blade, a manually operable actuator
operatively connected to said linkage for applying actuating forces
thereto at a common point therebetween, and restraining means
operatively connected to said linkage for controlling the movement
thereof to effect operation of said blade, said restraining means
preventing actuation of said blade in response to movement of said
actuator until said restraining means has been overcome, whereby
said restraining means is overcome when a predetermined tension is
produced in the portion of the strap between the first and second
points thereon thereafter to cause actuation of said blade to
effect severing of the strap, said predetermined tension being
independent of the point at which the operator manually engages
said actuator to apply the operating forces thereto.
6. The binder strap tensioning and severing tool set forth in claim
5, wherein said common point for applying actuating forces between
said linkage and said actuator is fixed with respect to said
actuator.
7. The binder strap tensioning and severing tool set forth in claim
5, wherein said common point for applying actuating forces between
said linkage and said actuator is fixed with respect to said
linkage.
8. The binder strap tensioning and severing tool set forth in claim
5, wherein said common point for applying actuating forces between
said linkage and said actuator is fixed with respect to both said
linkage and said actuator.
9. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said abutment and said gripper for movement relative
to each other in a strap-tensioning direction to tension the
portion of the strap between the first and second points thereon, a
blade for severing the strap along the portion thereof between the
first and second points thereon, a manually-operable actuator, a
linkage, a first drive train interconnecting said linkage and said
gripper, a second drive train interconnecting said linkage and said
blade, a third drive train interconnecting said linkage and said
actuator, the force for operating said gripper being exerted from
said actuator through said third drive train and said linkage and
said first drive train to said gripper, the force for operating
said blade being exerted from said actuator through said third
drive train and said linkage and said second drive train to said
blade, restraining means operatively connected to said linkage for
controlling the movement thereof to effect operation of said blade,
said restraining means preventing actuation of said blade in
response to movement of said actuator until said restraining means
has been overcome, whereby said restraining means is overcome when
a predetermined tension is produced in the portion of the strap
between the first and second points thereon thereafter to cause
actuation of said blade to effect severing of the strap, said
predetermined tension being independent of the point at which the
operator manually engages said actuator to apply the operating
forces thereto.
10. A binder strap tensioning and severing tool comprising a frame,
an abutment on said frame for engaging a binder strap at a first
point thereon, a gripper on said frame for engaging the binder
strap at a second point thereon, said gripper being mounted for
movement in a strap-tensioning direction with respect to said
abutment for tensioning the portion of the strap between the first
and second points thereon, a link operatively connected to said
gripper, an actuator operatively connected to said link for moving
said gripper in the strap-tensioning direction, a blade operatively
connected to said link for severing the strap along the portion
thereof between the first and second points thereon, and
restraining means operatively connected to said link for
controlling the movement thereof to effect operation of said blade,
said restraining means preventing actuation of said blade in
response to movement of said actuator until said restraining means
has been overcome, the connection between said link and said
actuator being at a fixed point on said link, the connection
between said link and said gripper being at a fixed point on said
link, the connection between said link and said blade being at a
fixed point on said link, the connection between said link and said
restraining means being at a fixed point on said link, whereby said
restraining means is overcome when a predetermined tension is
produced in the portion of the strap between the first and second
points thereon thereafter to cause actuation of said blade to
effect severing of the strap, said predetermined tension being
independent of the point at which the operator manually engages
said actuator to apply the operating forces thereto.
11. The binder strap tensioning and severing tool set forth in
claim 10, wherein said gripper moves with respect to said abutment
along a rectilinear path.
12. A binder strap tensioning and severing tool comprising a frame,
an abutment on said frame for engaging a binder strap at a first
point thereon, a gripper for engaging the binder strap at a second
point thereon, means mounting said gripper on said frame for
movement in a strap-tensioning direction with respect to said
abutment for tensioning the portion of the strap between the first
and second points thereon, a first pin carried by said frame at a
fixed point thereon, and a first link pivotally mounted on said
first pin, a second pin carried by said first link at a fixed point
thereon, and a second link pivotally mounted at one point thereof
on said second pin and operatively connected at another point
thereof to said gripper, an actuator pivotally mounted at one point
thereof on said frame and operatively connected at another point
thereof to said second link for moving said gripper in the
strap-tensioning direction, a blade operatively connected to said
first link for severing the strap along the portion thereof between
the first and second points thereon, and restraining means
operatively connected to said first link for controlling the
movement thereof to effect operation of said blade, said
restraining means preventing actuation of said blade in response to
movement of said actuator until said restraining means has been
overcome, the connection between said second link and said actuator
being at a fixed point on said second link, whereby said
restraining means is overcome when a predetermined tension is
produced in the length of strap between the first and second points
thereon thereafter to cause actuation of said blade to effect
severing of the strap, said predetermined tension being independent
of the point at which the operator manually engages said actuator
to apply the operating forces thereto.
13. The strap tensioning and severing tool set forth in claim 12,
wherein said second link is pivotally mounted adjacent to one end
thereof on said second pin, said second link is operatively
connected adjacent to the other end thereof to said gripper, and
said second link is operatively connected adjacent to a point
intermediate said ends to said actuator.
14. The strap tensioning and severing tool set forth in claim 12,
wherein said actuator is pivotally mounted on said first pin.
15. The binder strap tensioning and severing tool set forth in
claim 12, and further comprising a third link having one end
thereof operatively connected to said second link at said fixed
point on said second link, said third link having the other end
thereof operatively connected to said actuator.
16. The binder strap tensioning and severing tool set forth in
claim 12, and further comprising a tensioning rod carrying said
gripper and operatively connected to said second link at said other
point thereof.
17. A binder strap tensioning and severing tool comprising a frame,
an abutment on said frame for engaging a binder strap at a first
point thereon, a gripper for engaging the binder strap at a second
point thereon, means mounting said gripper on said frame for
movement in a strap-tensioning direction with respect to said
abutment for tensioning the portion of the strap between the first
and second points thereon, a first pin carried by said frame at a
fixed point thereon, a first link pivotally mounted on said first
pin, a second pin carried by said first link at a fixed point
thereon, and a second link pivotally mounted at one point thereof
on said second pin and operatively connected at another point
thereof to said gripper, an actuator pivotally mounted at one point
thereof on said frame and operatively connected at another point
thereof to said second link for moving said gripper in the
strap-tensioning direction, a blade operatively connected to said
first link for severing the strap along the portion thereof between
the first and second points thereon, the connection between said
second link and said actuator being at a fixed point on said second
link, the length of the effective lever arm for applying forces
between said fixed point and said gripper being fixed, the length
of the effective lever arm for applying forces between said fixed
point and said second pin being fixed, a roller on said first link,
a detent pivotally mounted on said frame and having a recess
therein, said detent being pivotal between a first position wherein
said roller is seated in said recess to prevent movement of said
blade and a second position wherein said roller is positioned out
of said recess to permit strap-severing movement of said blade, and
restraining means holding said detent in said first position
thereof until a predetermined tension is produced in the length of
strap between the first and second points thereof whereupon said
detent is moved to the second position thereof to permit movement
of said roller from said recess and subsequent strap-severing
movement of said blade.
18. A binder strap tensioning and severing tool comprising a
gun-shaped housing including a handle portion and a
forwardly-projecting barrel portion, a manually-operable actuator
mounted on said housing and movable toward and away from said
handle portion, a spring operatively connected between said
actuator and said housing and biased to urge said actuator away
from said handle portion, an abutment on said barrel portion
adjacent to the forward end thereof for engaging a binder strap at
a first point thereon, a gripper for engaging the binder strap at a
second point thereon, means mounting said gripper on said barrel
portion for movement in a strap-tensioning direction with respect
to said abutment for tensioning the portion of the strap between
the first and second points thereon, a blade on said housing for
severing the strap along the portion thereof between the first and
second points thereon, a common linkage interconnecting said
gripper and said blade, said actuator being operatively connected
to said linkage for applying forces thereto at a common point
therebetween, and restraining means operatively connected to said
linkage for controlling the movement thereof to effect operation of
said blade, said restraining means preventing actuation of said
blade in response to movement of said actuator until said
restraining means has been overcome, whereby said restraining means
is overcome when a predetermined tension is produced in the length
of strap between the first and second points thereon thereafter to
cause actuation of said blade to effect severing of the strap, said
predetermined tension being independent of the point at which the
operator manually engages said actuator to apply the operating
forces thereto and being independent of the force exerted by said
spring.
19. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, an actuator operatively connected both
to said gripper and to said blade, said tool having a
strap-tensioning mode wherein the force exerted by said actuator is
applied to said gripper for moving said gripper in the
strap-tensioning direction and having a strap-severing mode wherein
a portion of the force exerted by said actuator is applied to said
blade for moving said blade in a strap-severing direction, a detent
mechanism having a first condition for placing said tool in the
strap-tensioning mode thereof and having a second condition for
placing said tool in the strap-severing mode thereof, and
restraining means for holding said detent mechanism in said first
condition until a predetermined tension is reached in the length of
strap between the first and second points thereon whereupon said
detent mechanism is actuated into the second condition thereof,
whereby the force exerted by said actuator in the strap-tensioning
mode is utilized substantially in strap-tensioning and in
overcoming said restraining means and a portion of the force
exerted by said actuator in the strap-severing mode is utilized to
cause severing movement of said blade.
20. The binder strap tensioning and severing tool set forth in
claim 19, wherein said detent mechanism includes two members, a
roller on one of said members, the other of said members having a
recess therein for receiving said roller, said detent mechanism
being in said first condition when said roller is disposed in said
recess and said detent mechanism being in said second condition
when said roller is disposed out of said recess.
21. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, an actuator operatively connected both
to said gripper and to said blade, said tool having a
strap-tensioning mode wherein the force exerted by said actuator is
applied to said gripper for moving said gripper in the
strap-tensioning direction and having a strap-severing mode wherein
a portion of the force exerted by said actuator is applied to said
blade for moving said blade in a strap-severing direction, a detent
mechanism having a first condition for placing said tool in the
strap-tensioning mode thereof and having a second condition for
placing said tool in the strap-severing mode thereof, and spring
biased restraining means for holding said detent mechanism in said
first condition until a predetermined tension is reached in a
length of strap between the first and second points thereon
whereupon said detent mechanism is actuated into the second
condition thereof, whereby the force exerted by said actuator in
the strap-tensioning mode is utilized substantially in
strap-tensioning and in overcoming said restraining means and a
portion of the force exerted by said actuator in the strap-severing
mode is utilized to cause severing movement of said blade.
22. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, an actuator operatively connected both
to said gripper and to said blade, said tool having a
strap-tensioning mode wherein the force exerted by said actuator is
applied to said gripper for moving said gripper in the
strap-tensioning direction and having a strap-severing mode wherein
a portion of the force exerted by said actuator is applied to said
blade for moving said blade in a strap-severing direction, a detent
mechanism including a movable armature and a magnet, said movable
armature being operatively connected to said actuator and having a
first condition for placing said tool in the strap-tensioning mode
thereof and having a second condition for placing said tool in the
strap-severing mode thereof, said magnet holding said armature in
said first condition until a predetermined tension is reached in
the length of strap between the first and second points thereon
whereupon said armature is moved into the second condition thereof,
whereby the force exerted by said actuator in the strap-tensioning
mode is utilized substantially in strap-tensioning and in
overcoming said magnet and a portion of the force exerted by said
actuator in the strap-severing mode is utilized to cause severing
movement of said blade.
23. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, an actuator operatively connected both
to said gripper and to said blade, said tool having a
strap-tensioning mode wherein the force exerted by said actuator is
applied to said gripper for moving said gripper in the
strap-tensioning direction and having a strap-severing mode wherein
a portion of the force exerted by said actuator is applied to said
blade for moving said blade in a strap-severing direction, a detent
mechanism including a piston in a cylinder having a valve therefor,
said piston being operatively connected to said actuator and having
a first position for placing said tool in the strap-tensioning mode
thereof and having a second position for placing said tool in the
strap-severing mode thereof, said cylinder carrying said piston and
having the pressure therein reduced in response to movement of said
actuator to hold said piston in said first position thereof until a
predetermined tension is reached in the length of strap between the
first and second points thereof, and said valve on said cylinder
accommodating passage of air into said cylinder into the area of
reduced pressure therein to hold said tool in said strap-tensioning
mode until the predetermined tension is reached whereupon said tool
is moved into said strap-severing mode thereof, whereby the force
exerted by said actuator in the strap-tensioning mode is utilized
substantially in strap-tensioning and in overcoming the action of
said piston in said cylinder and a portion of force exerted by said
actuator in the strap-severing mode is utilized to cause severing
movement of said blade.
24. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
means for mounting said gripper for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a blade
for severing the strap along the portion thereof between the first
and second points thereon, linkage operatively connected to said
gripper and said blade, an actuator operatively connected to said
linkage, said linkage having a strap-tensioning mode wherein the
force exerted by said actuator through said linkage is applied to
said gripper for moving said gripper in a strap-tensioning
direction and having a strap-severing mode wherein force exerted by
said actuator through said linkage is applied to said blade for
moving said blade in a strap-severing direction, a detent having a
first condition for placing said linkage in the strap-tensioning
mode thereof and having a second condition for placing said linkage
in the strap-severing mode thereof, restraining means for holding
said detent in said first condition until a predetermined tension
is reached in the length of strap between the first and second
points thereon whereupon said detent is moved into the second
condition thereof, and means mounting said actuator for movement
thereof between a rest position and a fully-actuated position along
a predetermined regular path with respect to said abutment, the
predetermined path of travel of said actuator during said
strap-tensioning mode of said linkage being identical to the
predetermined path of travel of said actuator during said
strap-severing mode of said linkage thereby to provide a single
predetermined path of travel for said actuator between said rest
position and said fully actuated position thereof, whereby said
restraining means is overcome when a predetermined tension is
produced in the portion of the strap between the first and second
points thereon thereafter to shift said linkage from the
strap-tensioning mode thereof to the strap-severing mode thereof to
cause actuation of said blade to effect severing of the strap, said
predetermined tension being independent of the point at which the
operator manually engages said actuator to apply the operating
forces thereto.
25. A binder strap tensioning and severing tool comprising a hollow
housing, an abutment on said housing for engaging a binder strap at
a first point thereon, a gripper shiftably mounted on said housing
for engaging the binder strap at a second point thereon, mechanism
for moving said gripper relative to said abutment in a
strap-tensioning direction to tension the portion of the strap
between the first and second points thereon, an actuator mounted on
said housing and operatively connected to said mechanism for
operating said mechanism in the strap-tensioning direction, a blade
shiftably mounted on said housing and operatively connected to said
actuator for severing the strap along the portion thereof between
the first and second points thereon, adjustable restraining means
mounted in said housing and operatively connected to said blade for
controlling the movement thereof, said restraining means preventing
actuation of said blade in response to movement of said actuator
until said restraining means has been overcome, means for adjusting
the restraining force exerted by said restraining means on said
blade, said housing having a window therein and being provided with
a first index marker adjacent to said window, a plate slidably
mounted within said housing in position to close and to seal said
window and having a second index marker thereon viewable through
said window and cooperating with said first index marker, and means
interconnecting said restraining means and said plate to cause
movement of said plate in response to adjustment of said adjustment
means, whereby the position of said plate and thereby the
cooperation between said index markers provides a visual indication
of the force exerted by said restraining means while sealing the
window in said housing.
26. A binder strap tensioning and severing tool comprising a
gun-shaped housing including a hand grip portion, a forwardly
extending frame carried by said housing, and a deflecting surface
carried by said housing and extending rearwardly and upwardly with
respect to said hand grip portion, an abutment on the outer end of
said frame for engaging the binder strap at a first point thereon
and accommodating the passage of the free end of the binder strap
therepast, a gripper shiftably mounted on said frame for engaging
the binder strap at a point thereon and accommodating the passage
of the free end of the binder strap therethrough and along a
predetermined path adjacent to said frame and along said deflecting
surface and upwardly and outwardly over the upper end of said
housing, mechanism for moving said gripper relative to said
abutment in a strap-tensioning direction to tension the portion of
the strap between the first and second points thereon and to feed
the free end of the binder strap along the predetermined path, an
actuator mounted on said housing and operatively connected to said
mechanism for operating said mechanism in the strap-tensioning
direction, a blade shiftably mounted on said frame, an elongated
arm mounted on said frame and extending longitudinally thereof and
operatively connected both to said blade and to said actuator,
whereby operation of said actuator causes operation of said
mechanism in the strap-tensioning direction to tension the portion
of the strap between the first and second points thereon and to
feed the free end of the binder strap along the predetermined path
and across said deflecting surface and thereafter operating said
blade via said arm to effect severing of the binder strap without
interfering with the passage of the free end of the binder strap
along the predetermined path therefor.
27. A binder strap tensioning and severing tool comprising an
abutment for engaging a binder strap at a first point thereon, a
gripper for engaging the binder strap at a second point thereon,
said gripper being mounted for movement in a strap-tensioning
direction with respect to said abutment for tensioning the portion
of the strap between the first and second points thereon, a linkage
operatively connected to said gripper, manually operable actuator
operatively connected to said linkage for moving said gripper in
the strap-tensioning direction, a blade operatively connected to
said linkage for severing the strap along the portion thereof
between the first and second points thereon, and restraining means
operatively connected to said linkage for controlling the movement
thereof to effect operation of said blade, said restraining means
preventing actuation of said blade in response to movement of said
actuator until said restraining means has been overcome, the
connection between said linkage and said actuator being at a fixed
point on said linkage, the effective length of the lever arm for
applying forces between said fixed point and said gripper being
fixed, the effective length of the lever arm for applying forces
between said fixed point and said restraining means being fixed,
whereby said restraining means is overcome when a predetermined
tension is produced in the portion of the strap between the first
and second points thereon thereafter to cause actuation of said
blade to effect severing of the strap, said predetermined tension
being independent of the point at which the operator manually
engages said actuator to apply the operating forces thereto.
Description
The present invention relates to the art of strap tensioning and
severing tools of the hand-tool type, and particularly to a
highly-improved hand tool for tensioning and securing flexible
binder straps around bundles of wire or other objects.
In recent years there has been a very material increase in the
production, repair, and maintenance of complicated electrical and
electronic installations, and the industry for some time has been
seeking improved means by which bundles of wires and electrical
leads may be quickly and economically secured and bound together.
Substantial improvements have been made in flexible binder straps
for this purpose, and U.S. Pat. No. 3,197,829 issued to the present
applicants on Aug. 3, 1965, illustrates and claims one such strap.
Binder straps of this general kind comprise a
longitudinally-extending strap having a connector means adjacent
one end thereof, with the other end being free and adapted to be
wrapped around the object or bundle to be bound and thereupon to be
slid through the connector in a tightening or binding movement.
Connectors or straps of this kind customarily are provided with
latching or securing structure for holding or retaining the strap
in its tightened condition once the strap has been placed in the
tightened or tensioned condition. For the sake of neatness, and, in
order to reduce the number of loose ends that may exist in
conjunction with the circuitry, it is desirable, once the strap has
been tightened about the bundle, to cut or sever the free strap end
which extends from the connector portion of the strap assembly.
One of the important objects of the present invention is to provide
a highly-improved hand tool for quickly and economically applying
flexible straps of the foregoing kind to bundles of wire and the
like and for thereupon severing the free or loose ends of the
straps, the tool having highly-improved means for applying
successive straps at uniform predetermined tensions, no matter how
the handle actuating the drive mechanism is gripped by the
user.
Another important object of the present invention is to provide a
strap tensioning and severing tool of the kind just stated, having
a pair of jaws for progressively tensioning the strap, drive
mechanism for actuating a strap-severing blade, and means for
applying force to both the jaws and the severing blade drive
mechanism, wherein additional means are employed for applying
restraining force upon the severing blade drive mechanism to
prevent blade severing movement thereof until a predetermined
tension is reached in the strap, and wherein further means are
included for substantially instantaneously relieving or reducing
the restraining force on the blade drive mechanism when the
predetermined tension in the strap is reached, whereby the blade
drive mechanism thereupon immediately and quickly actuates the
blade to sever the strap, thus ensuring that successively applied
straps will all be tensioned accurately and uniformly.
Another important object of the present invention is to provide a
strap tensioning and severing tool, of the kind referred to above,
which uniformly tensions successively applied straps regardless of
how the tool is held in the hand.
Still another important object of the present invention is to
provide, in a hand tool having the attributes described above,
relatively simple and highly-improved mechanism for bringing about
the tensioning and severing of the straps.
Still another object of the present invention is to provide in hand
tools of the foregoing kind improved means for selectively varying
the predetermined tension in the straps applied.
Yet another object of the invention is to provide a strap
tensioning and severing tool of the foregoing kind which is
relatively inexpensive to manufacture, entirely reliable in its
use, very durable, and comfortable and convenient for use.
These and other objects and advantages of the present invention
will be apparent from the following description of a preferred
embodiment thereof, with certain variations, taken with the
drawings wherein:
FIG. 1 is a side elevation view of a tool embodying the present
invention, the tool being illustrated in a condition wherein it has
received a binder strap of the general kind referred to above and
the tool is about to be actuated to tighten or tension the strap
about a bundle;
FIG. 2 is a top plan view of the tool, with the strap and bundle
being omitted;
FIG. 3 is an end view of the tool, as seen from the right in FIG.
1;
FIG. 4 is a fragmentary cross-sectional view taken through the tool
substantially along the line 4--4 in FIG. 1;
FIG. 5 is an enlarged end view of the tool taken substantially
along the line 5--5 in FIG. 1, with the strap being omitted, and
with an end plate on the tool being partially cut away so as to
show a strap-severing blade which is located on the forward end of
the tool beneath the plate;
FIG. 6 is a side view of the tool in the same condition illustrated
in FIG. 1, but with the strap omitted and with a side plate on the
handle portion of the tool removed to illustrate the parts on the
interior of the tool, certain of the parts of the tool being shown
in cross section for better illustration;
FIG. 7 is a view of the tool similar to FIG. 6, but showing the
positions of the parts of the tool after the tool has been actuated
to tension the strap and showing the positions of the parts of the
tool prior to severance of the strap, certain parts of the tool
being cut away for better illustration;
FIG. 8 is a view like FIG. 7, but showing the parts in the
positions which they occupy immediately after the severing blade
has been actuated, or at the instant it is actuated, to cut the
strap;
FIG. 9 is a fragmentary elevational view of the lower portion of
the handle of the tool, with the handle plate removed, and with a
tensioning selector moved to a position different from that
illustrated in the preceding figures, so as to effectively change
the tension at which the strap will be severed, FIG. 9 also
illustrating a modification used for preventing inadvertent
variation of a selected tension;
FIG. 10 is a fragmentary view of the lower portion of the handle of
the tool, with the handle plate removed to illustrate a magnetic
variation of the means for applying restraining force to the
severing blade drive mechanism and for substantially
instantaneously relieving or reducing that force upon the
attainment of the predetermined tension in the strap, whereupon the
blade drive mechanism will actuate the blade to sever the strap;
and
FIG. 11 is a view like FIG. 10 showing a pneumatic variation for
accomplishing the same purpose.
Referring initially to FIGS. 1-6, it will be seen that the present
tool, in the embodiment shown, is provided with a configuration
resembling that of a gun having a handle portion and a
forwardly-projecting portion somewhat similar in position to a gun
barrel. The main body portion of the gun-shaped tool is comprised
of a casting 20 of aluminum or the like having a handle portion 21
and a forwardly-projecting portion 22. The handle portion 21 is
recessed so as to provide a side wall 23. The rear peripheral
portion of the handle portion 21 is defined by a
laterally-extending flange 24 which extends downwardly and merges
with a lower wall flange 25. This lower flange 25, on the other
hand, extends forwardly and merges with the lower end of a similar
flange 26 which defines the forward periphery of the handle portion
21 of the gun, the upper end of the flange 26 terminating at 27. As
best seen in FIG. 6, the upper end of the rear flange 24 merges
with a rearwardly-directed flange 28, the rear end of which merges
with an upstanding abutment flange 29. The upper end of the flange
29, in turn, merges with a forwardly-directed flange 30. The
forwardmost end of the flange 30 is downturned at 31 and terminates
at 32. It will be observed that the flanges 28, 29, and 30 provide
a socket-like configuration for receiving a relatively-heavy
compression spring 33.
The handle portion of the tool just described is covered by a cover
plate 34 having inturned lateral flanges 35 which mate with and
have the same configuration as the previously-described flanges 24,
25, 26, 28, 29, 30 and 31. Suitable bosses 36 and 37 are formed
integrally with the wall 23 and are suitably threaded to receive
screws 38 and 39 which extend through openings in the plate 34 for
securing the plate in fixed position on the flanges 24, 25, 26, 28,
29, 30 and 31. The plate 34 thus encloses the handle portion of the
gun and the parts located therein.
The forwardly-projecting portion 22 of the casting is generally of
rectangular cross section (See FIG. 4), with a
longitudinally-extending slot 40 formed therein for slidably
receiving a longitudinally-extending tension rod 41, later to be
described.
The forwardmost end of the forwardly-projecting portion 22 of the
casting has a laterally-projecting boss 50 formed thereon having a
flat vertically-extending forward face 51 thereon and a sloping
face 52 (FIG. 7) formed on its rear side. Above the
triangular-shaped boss, the forwardmost portion of the
forwardly-projecting portion 22 of the basic casting of the tool
has a laterally-projecting backup boss 53 formed thereon, the under
surface of which overhangs the triangularly-shaped boss 50, thus
defining a slot 54 (FIG. 5) for receiving the free end 55 of a
strap designated generally by the numeral 56.
As previously suggested, the strap 56 may be of a construction like
or similar to that illustrated in U.S. Pat. No. 3,197,829 issued to
the present applicants. The strap has a connector portion 57 fixed
to one end 58 of the strap, with the free end of the strap 55
capable of being wrapped around the bundle 59 and then passed
through an opening in the connector 57, so as to form a closed loop
about the bundle, as illustrated in FIG. 1. The loop formed by the
strap, in straps of this kind, is tightened by pulling on the free
end 55 of the strap while preferably restraining the end portion 58
and the connector 57 against movement. The connector 57, in straps
of this kind, is provided with latching means acting upon that
portion of the free end 55 of the strap within the connector, so as
to prevent a strap loop from loosening, once the loop has been
tightened.
The tensioning rod 41 is longitudinally slidably disposed in the
slot 40, as previously described, and the rod 41 is preferably
provided with a longitudinally-extending slot 60 through which
there extends a screw 61 which is threaded into the element 22 and
has a head 62 which overlies the tension rod 41 along the lateral
sides of the slot 60. The tension rod 41 is thus retained in the
slot 40. The forward end of the tension rod 41 carries a
laterally-extending screw 63 upon which there is pivotally mounted
a gripper 64 having teeth 65 formed on its upper side for gripping
the under side of the free end 55 of the strap 56. The back side of
the gripper 64 is provided with a spring, not shown, having one end
fixed to the tension rod 41 and the other end bearing against the
wall of a recess in the gripper 64, so as continuously to urge the
gripper 64 to be pivoted in the counterclockwise direction, as
viewed in FIG. 1. This means for causing a gripping pawl, such as
the gripper 64, constantly to be urged in a direction about an
axis, such as that provided by the screw 63, is well-known, and for
this reason it is believed unnecessary to illustrate the spring
just referred to. When the tension rod 41 is in its forward
position, as illustrated in FIG. 1, the forward side 66 of the
gripper 64 bears against the sloping wall 52 of the triangular boss
50, thus camming the gripper 64 to the normal position thereof seen
in FIGS. 1 and 6.
Above the position of the gripper 64, the tension rod 41 has a
laterally-projecting backup lug 67 forward thereon which overhangs
the gripper 64 and serves to back up or support the upper side of
the free end 55 of the strap 56 when the teeth 65 of the gripper 64
forcefully engage the free end 55 of the strap.
A forwardly-projecting lever arm 70 is pivotally mounted on the
side of the element 22, below the level of the tension rod 41, by
means of a pin 71. If desired, the pin may be press-fitted in a
suitable opening provided in the element 22 and rotatably received
in a corresponding opening in the lever arm 70, as seen in FIG. 4.
The forward end of the lever arm 70 extends to a position spaced
somewhat below the triangularly-shaped boss 50, and the forward
extremity of the lever arm is provided with a pair of
forwardly-projecting fingers 72 and 73 which are received in two
corresponding slots 74 and 75 formed in a cutter blade 76. The
upper edge 77 of the cutter blade is sharpened to provide a knife
edge, and the body of the cutter blade 76 is slidably received on
the front face of the triangularly-shaped boss 50. The body of the
cutter blade is provided with an elongated slot 78 for
accommodating a screw 79 which extends through the slot 78 and is
threaded into the triangular boss 50. The cutter blade 76 is
slidably retained in this position by a cover plate 80 which is
secured to the front of the tool by the screw 79 and by another
screw 81 which is threaded into the forward end of the element 22,
as best seen in FIG. 5. The plate 80 has a slot formed therein
which mates with the slot 54 previously referred to. The normal
positions of the lever arm 70 and the cutter blade 76 are
illustrated in FIGS. 1 and 6, but it will be appreciated that, if
and when the lever arm 70 is pivoted about the pin 71 in the
clockwise direction, as viewed in these figures, the cutter blade
76 will be slidably raised so as to bring its knife-like upper edge
77 into cutting contact with the free-end portion 55 of the strap
56.
The tool is provided with a forwardly and downwardly extending
trigger or actuator handle 85, the exposed portion of which, if
desired, may be suitably covered by a suitable plastic or pliable
sheath 86. The lower portion of the actuator handle may comprise a
transverse web 87 having rearwardly-directed flanges 88 and 89
formed thereon. The web 87 terminates at 90, but the two flanges 88
and 89 extend upwardly between the wall 23 of the handle portion of
the tool and cover plate 34. At their upper ends, the two flanges
88 and 89, which are laterally spaced apart, are pivotally mounted
on a pin 91. One end of the pin 91 is received in an opening in the
wall 23 of the handle portion of the main frame or casting of the
tool, and the other end of the pin 91 is received in an opening 92
in the handle plate 34, as seen in FIG. 1. This pin 91 provides a
fixed axis for the actuator handle or trigger 85 and for certain
other parts of the tool which will later be described.
Between the flanges 88 and 89 of the trigger or actuator handle 85
there is an actuator link 95. The lower portion of the actuator
link 95 is secured in place by a transverse pin 96 which is carried
between the flanges 88 and 89. The forward edge of the lower
portion of the actuator link 95 may lie against the inner surface
of the web 87 of the trigger 85. The upper portion of the actuator
link 95 has a somewhat dog-leg configuration (See FIG. 7), and the
upper extremity of the actuator link is pivotally mounted upon the
fixed pin 91. Intermediate the pins 91 and 96, the actuator link 95
has a pin 97 fixed thereon which pivotally receives one end of a
drive link 98. The other end of the drive link 98 is pivotally
received on a pin 99 which is fixed to a lever link 100 midway
between the opposite ends of the latter. The upper end of the lever
link 100 has a pin 101 fixed thereon which rides in a
vertically-elongated slot 102 formed in the rear end of the tension
rod 41. The lower end of the lever link 100, on the other hand, is
pivotally mounted upon a pin 103 which is fixed in and extends
laterally between a pair of identical, spaced-apart link plates 104
and 105, both of which will be referred to at some length
hereinafter.
The spring 33, which is retained in the socket-like configuration
provided by the flanges 28, 29 and 30 at the upper rear portion of
the handle of the tool, has already been referred to. This spring
33 may be sometimes referred to hereinafter as a return spring. The
rear end of this spring 33 bears against the inner surface of the
flange 29, and the forward end of the spring forcefully bears
against an end 110 of a return yoke designated generally by the
numeral 111. This return yoke 111 has a pair of
forwardly-projecting arms 112 and 113 (the latter of which is shown
only in FIG. 7). The forwardmost ends of the yoke arms 112 and 113
are respectively pivotally secured, as by a pair of pins 114, to
the upper portions of the flanges 88 and 89 of the trigger or
actuator handle 85 somewhat below the position of the fixed pivot
pin 91. It will thus be understood that the return spring 33,
through the yoke 111, constantly urges the trigger or actuator arm
85, in the clockwise direction, as viewed in FIGS. 1 and 6.
It has previously been pointed out that the lower end of the lever
link 100 is pivotally mounted upon a pin 103 which is fixed in and
extends between the spaced-apart link plates 104 and 105. These
link plates 104 and 105 are disposed respectively immediately
inside the upper portions of the two flanges 88 and 89 as will be
fully understood from a careful study of FIGS. 6 and 7. The link
plates 104 and 105, at their forwardmost ends, have a pin 120 fixed
therein and extending laterally therebetween. This pin is received
in a rearwardly-opening slot 121 formed in the rear end of the
lever arm 70 which actuates the strap-severing blade 76 (See FIG.
6). The two link plates are of identical shape, and the forward and
upper portion of each link plate has a somewhat dog-leg
configuration, each link plate at its upper extremity being
pivotally mounted upon the fixed pin 91.
The lower right-end portions of the two link plates 104 and 105
have a pin 122 fixed therein and extending therebetween, and the
pin 122 rotatably carries a roller 123 between the link plates.
This roller co-operates with a pivoted cam or detent 125. The cam
member or detent 125 is pivotally mounted upon a pin 126, one end
of which is received in an opening in a boss (not shown) formed on
the inner surface of the plate 23 which forms one side of the
handle portion of the tool. The other end of the pin 126 (the end
closest to the eye in FIGS. 6 and 7) is received in an opening
provided in a similar boss formed on the inner surface of the
handle cover plate 34. It will thus be understood that the pin 126
provides a fixed axis about which the cam member or detent 125 may
pivot. The upper surface of the cam member or detent 125 is
provided with a cylindrically-concave recess 127 having a radius
only slightly larger than the radius of the roller 123, the recess
127 being slightly to the right of the pin 126, as seen in FIGS. 6
and 7. The right-hand extremity of the cam member or detent 125 has
an upwardly-extending portion 128 formed thereon which terminates
in a sloping cam surface 129. The opposite end of the cam member or
detent 125 is pivotally mounted upon a pin 130 which extends
between and is carried by the upper end portions of a pair of arms
131 and 132 of a tension yoke designated generally by the numeral
133. The lower ends of the two arms 131 and 132 are joined together
by a web 134. Between the two arms 131 and 132 there is slidably
mounted a tension block 135, the opposite sides of the block being
provided with longitudinally-extending recesses 136 which slidably
receive the two arms 131 and 132 and thus serve to guide the block
between the arms. The block 135 has a recess 137 therein which
opens at the bottom end of the block. Thus, as seen in FIG. 6, the
upper end of the block is, in effect, closed by a transverse web
138. The inner surface of this web 138 has an apertured boss 139
formed thereon which is threaded to receive the upper end portion
of a threaded tensioning rod 140. The lower end portion of this
tensioning rod 140 extends through an opening in the web 134 of the
yoke 133 and through a similar opening in the flange 25 at the
bottom of the handle of the tool. The lower extremity of the
tensioning rod 140 threadedly receives a transverse pin 150, the
pin 150 being secured against rotation upon the tensioning rod 140
by a second transverse pin 151.
A compression spring 155 has its upper end disposed in the cavity
137 within the tension block 135, with the uppermost end of the
spring 155 bearing against the inner surface of the web 138. The
lower end of the spring 155 bears against the upper surface of the
web 134 which extends between the yoke arms 131 and 132.
The opposite ends of the pin 150, which is secured upon the
lowermost end of the tensioning rod 140, respectively receive a
pair of wings 160 and 161 of an adjustment knob designated
generally by the numeral 162, the two wings 160 and 161 being
joined by a transverse web 163. The outer end of each wing 161 and
162 is curved, as at 164, to provide a camming surface, while flat
surfaces 165 and 166 are provided on opposite sides of each wing.
Each of the wings 160 and 161 adjacent its flat surface 165 is
provided with an outwardly-directed ledge 167, and each is provided
with an outwardly-extending ledge 168 adjacent its flat edge 166.
In FIGS. 1, 3, 6, 7, and 8, the flat surfaces 165 of the wings 160
and 161 of the adjustment knob 162 are shown to be bearing upon the
lower or outer surface of the flange 25 of the handle portion of
the gun. The elevation of the tensioning rod 140 and the tension
block 135 are thus fixed in there figures, with the downward
pressure of the spring 155 upon the web 134 of the tensioning yoke
133 causing the arms 131 and 132 of the yoke to pull constantly
downwardly on the pin 130, thus tending forcefully to pivot the
detent or cam member 125 in a counterclockwise direction, as seen
in the figures. The roller 123 on the link plates 104 and 105
normally resides in the recess 127 of the cam member or detent 125.
Thus, the pivoting force applied to the detent or cam member 125 is
transmitted and applied as a predetermined restraining force on the
link plates 104 and 105, as will be more fully explained
hereinafter.
In the operation of the tool illustrated in FIGS. 1--8, the strap
56 is looped about a bundle of wire or the like 59, with the free
end 55 of the strap fed through the connector 57. When the operator
is ready to tension the strap about the bundle and sever the free
end 55, the free end 55 is slipped laterally into the slot 54 at
the nose or front of the tool, as illustrated in FIG. 1. The tool,
in its normal condition, will be as seen in FIGS. 1 and 6, with the
gripper 64 cammed by the triangular boss 50 to an "open" position,
permitting easy receipt of the free end 55 of the strap between the
gripper and the backup member 67 on the tension rod 41. Having
deposited the strap in the tool in the fashion illustrated in FIG.
1, the operator grips the tool in his hand and pulls or squeezes
upon the trigger or actuator handle 85, thereby causing the latter
to be pivoted in a counterclockwise direction about the fixed pin
91. This motion of the trigger 85, and the force applied thereto,
is transmitted by the actuator link 95, the pin 97, the drive link
98, and the pin 99 to the lever link 100, thereby causing the
latter to pivot in a clockwise direction about the pin 103. This
force applied to the lever link and the resultant movement thereof
causes the pin 101 at the upper end of the drive link 100 to pull
the tension rod 41 to the right, as viewed in the figures.
Disengagement of the forward surface 66 of the gripper 64 from the
triangularly-shaped boss 50 permits the gripper immediately to
rotate in a counterclockwise direction, thereby causing its teeth
65 to grip the under side of the free end 55 of the strap.
Continued motion of the tension rod 41 toward the right causes the
connector portion 57 of the strap to bear against the forward
surface of the front plate 80 of the tool, whereupon further motion
of the tension rod 41 toward the right tightens the strap 56 about
the bundle 59. As the tension builds up in the free end 55 of the
strap, between the jaw provided by the front end portion of the
tool and the jaw provided by the gripper 64 and the backup 67, it
will be appreciated that the lateral force exerted upon the pin 103
at the lower end of the lever link 100 will continue to build up,
this force being applied by the pin 103 to the two link plates 104
and 105. It will also be remembered that the link plates 104 and
105 are pivotally mounted upon the pin 91. During this build-up of
force upon the link plates 104 and 105, these link plates would
pivot about the pin 91 if it were not for the restraining force
being applied to the link plates by the detent or cam member 125.
However, as the tension in the strap 55 reaches a predetermined
maximum, the lateral force on the pin 103 and upon the link plates
104 and 105 will reach a point at which the restraining force
applied by the detent or cam member 125 is overcome. At the moment
this occurs, the roller 123 will cam the detent or cam member 125
in a clockwise direction toward the position thereof illustrated in
FIG. 8, during which motion the roller 123 will snap out of the
recess 127, thereby substantially instantaneously relieving or
reducing the restraining force on the link plates 104 and 105 and
permitting the link plates 104 and 105 substantially instantly to
pivot from their normal position to the position thereof
illustrated in FIG. 8. This counterclockwise pivotation of the link
plates 104 and 105 about the pin 91 causes the transverse pin 120
at the forward extremities of the link plates to pivot the lever
arm 70 in a clockwise direction about the pin 71 to the position
shown in FIG. 8, thereby substantially instantaneously raising the
blade 76 and causing the upper edge 77 thereof to sever the free
end portion 55 of the strap.
At the moment severing of the strap occurs, the tension rod 41 will
be substantially instantaneously and rapidly drawn further to the
right, bringing the rear sloping edge of the gripper 64 into
contact with the head 62 of the screw 61, thereby causing the
gripper 64 momentarily to be cammed to its normal position, as
shown by the broken lines in FIG. 8, thereby releasing from its
grip the severed end 55 of the strap. This action will normally
cause the severed end 55 of the strap to be thrown out of the grip
of the gripper 64.
Instantly, after the strap portion 55 has been severed, thereby
causing the lateral force applied by the pin 103 to the link plates
104 and 105 to be substantially reduced, the sloping surface 129 of
the detent or cam member 125 will cam the roller 123 in a returning
motion back into the cylindrical concave recess 127, thus
immediately returning the link plates 104 and 105 to their normal
position. This returning motion of the link plates 104 and 105
instantly returns the lever arm 70 and the blade 76 to their normal
positions. The operator will also release his grip on the trigger
85, thereby permitting the return spring 33, through the action of
the return yoke 111, to return the trigger 85 to its normal
position, as illustrated in FIGS. 1 and 6. This restoration of the
trigger 85 to its normal position causes the drive link 98 and the
lever link 100 to return to the positions thereof seen in FIG. 6.
The returning motion of the lever link 100 moves the tension rod 41
to the left and to its normal position illustrated in FIGS. 1 and
6, thereby causing the gripper 64 to be cammed to its normal
position by its contact with the sloping surface 52 of the
triangularly-shaped boss 50.
It will be appreciated that, by rotating the tension adjustment
knob 162 about the axis of the tensioning rod 140, the tension
block 135 will be selectively raised or lowered, thereby
selectively varying the compression of the spring 155, and thus
selectively varying the restraining force applied by the cam member
or detent 125 upon the link plates 104 and 105. This selective
variation of the restraining force applied to the link plates
effectively selectively varies the predetermined tension that will
be applied to the free end 55 of the strap 56 at the time of its
severance. If desired, the tension block 135 may have an index line
135a (FIG. 1) scribed thereon. This scribe line may be made visible
to the operator through an opening 34a provided in the handle plate
34, the elevation of the scribe line 135a in the window serving to
indicate the restraining force being applied to the link plates 104
and 105, and thus the predetermined tension that will be produced
in the strap 56. If desired, reference or index lines 34b may be
scribed on the outer surface of the handle plate 34 adjacent the
window 34a, as illustrated in FIG. 1.
Another way of selectively varying the restraining force applied to
the link plates 104 and 105, is to pivot the adjustment knob 162
180.degree. about the axis of the pin 150. It will be observed that
the pin 150 is eccentrically located in the adjustment knob 162
(FIG. 6). Thus, the adjustment knob may be pivoted in a
counterclockwise direction about the pin 150 from the position of
the knob illustrated in FIGS. 1, 6, 7, and 8 to the position
thereof illustrated in FIG. 9. During this pivotal movement, the
cam surfaces 164 on the wings 160 and 161 of the knob bear on the
under surface of the flange 25 of the handle of the tool, thereby
progressively camming the pin 150 from the position thereof shown
in FIG. 6 to the position thereof shown in FIG. 9. This lowering of
the position of the pin 150 lowers the tension block 135, thereby
increasing the force of the spring 155 on the yoke 133 and thus
increasing the predetermined restraining force applied to the link
plates 104 and 105. This, in turn, increases the predetermined
force that will be produced in the strap between the gripper 64 and
the cover plate 80 at the instant before severing occurs.
In FIG. 9, the adjustment knob 162 is shown to have been turned
90.degree. about the axis of the tension rod 140, from the position
of the knob illustrated in FIG. 6. With the adjustment knob in the
position seen in FIG. 9, a set screw 180 may be threaded into a
suitable opening provided in the flange 25 so as to prevent an
operator from inadvertently rotating the knob 162 about the axis of
the tension rod 140, while, at the same time, permitting the knob
to be rotated from a high-tension position to a low-tension
position, and vice versa, about the axis of the pin 150. If it is
desired that the adjustment knob 162 not be permitted to be moved
in any adjusting fashion, a headed screw may be employed in place
of the screw 180, with the head overlying the ledge 168 on the
adjustment knob.
In FIG. 10, there is illustrated a magnetic variation employed in
the tool of the present invention, for applying a predetermined
restraining force to the link plates 104 and 105. In this
variation, the roller 123 is omitted, and in its place a link 190
is pivotally mounted upon the pin 129 between the link plates. The
lower end of the link 190 is pivotally secured to a flapper member
191 by a pin 192. The flapper member 191, in turn, is pivotally
mounted upon a pin 193 fixed between a pair of bosses 194 formed on
the inner surface of the flange 26 of the handle portion of the
tool. The flapper member 191, like the handle portion of the tool,
may be formed of nonmagnetic metal, such as aluminum, and the lower
surface of the flapper member 191 may have applied thereto, as by
screws, an armature plate 195 of magnetic material, such as iron,
adapted to coact with a permanent magnet 196 suitably installed and
held in place in the lower portion of the interior of the handle by
bosses 197 and 198. In this construction, it will be appreciated
that the permanent magnet 196, through the plate 195, the flapper
member 191, and the link 190, will apply a predetermined
restraining force to the link plates 104 and 105, in substantially
the same fashion as the structure previously described. Similarly,
when the lateral force applied by the pin 103 upon the link plates
104 and 105 becomes sufficiently great during the tensioning of a
strap, the restraining force will suddenly be overcome, thereby
pulling the flapper member 191 and its plate 195 in a pivoting
motion upwardly away from the magnet 196, thus permitting the link
plates substantially instantly to pivot about the pin 91, thereby
to actuate the severing blade.
A further revision is illustrated in FIG. 11, wherein the pin 122
has a link 200 pivotally mounted thereon, the lower end of which is
pivotally mounted upon a wrist pin 201 of a piston 202. This piston
202 is slidably mounted in a cylinder 203 contained in the
lowermost portion of the handle of the tool, the cylinder being
provided with one or more sealing rings 204. The lower end of the
cylinder has a tapered valve seat 205 formed therein, with the
lower end of the concave valve seat joining a downwardly-extending
opening 206 which extends through the headed cylinder and through
the flange 25 of the handle of the tool. A valve member 207 is
seated in the valve seat. A valve stem 208 extends from the valve
through the opening 206 and to the exterior of the tool. The outer
extremity of the valve stem 208 is threaded to receive an
adjustment nut 209, and a compression spring 210 is disposed
between the nut 209 and the under surface of the flange 25. The
spring 210 serves constantly to urge the valve member 207 into
closed position in the valve seat 205. A one-way ball-check valve
211 is also installed in a passage extending from the interior of
the cylinder to the exterior of the tool, with a compression spring
212 urging the ball to its closed position in a valve seat, as
illustrated in FIG. 11. It will be understood that this variation
illustrated in FIG. 11 will also serve to apply a predetermined
restraining force upon the link plates 104 and 105 to cause a
predetermined tension to be reached in a strap end before it is
severed. As the strap end is tensioned, the lateral force, as
previously stated, applied by the pin 103 to the link plates 104
and 105, will tend to cause the plates to pivot and thus, through
the link 200, to raise the piston 202 in the cylinder 203. This
tendency will produce a vacuum between the head of the piston and
the head of the cylinder, thereby producing and causing a
predetermined restraining force to be applied to the link plates
104 and 105. As the force upon the plates 104 and 105 is increased
by the pin 103, the vacuum within the cylinder will reach a point
at which the valve 207 will be raised, thereby substantially
instantaneously permitting air to flow through the passage 206 and
into the cylinder, thereby nullifying the vacuum, and reducing or
relieving the restraining force upon the link plates 104 and 105,
thus permitting the link plates to actuate the cutter blade 76.
Upon severance of the strap end 55, and upon return of the parts of
the tool to their original positions by reason of the force of the
spring 33, the piston 202 will be restored to its normal position,
as illustrated in FIG. 11. During this restoring movement of the
piston, the air in the cylinder will be expelled through the
passage in which the ball-check valve 211 is located.
In the case of the pneumatic means shown in FIG. 11 for applying a
restraining force to the link plates 104 and 105, it will be
appreciated that this restraining force may be selectively varied,
and the predetermined tension to be achieved in the strap 56
likewise to be varied, by selective adjustment of the nut 209 on
the valve stem 208. Rotation of the nut 209 on the valve stem will
vary the compression of the spring 210 and thus will vary the point
at which the valve member 207 will pop upwardly into an opening
position so as substantially instantaneously to reduce or relive
the restraining force on the link plates 104 and 105, thereby
permitting pivotation of the link plates about the pin 91 to
actuate the cutter blade 76 in a strap-cutting motion.
It was stated at the outset in this specification that one of the
objects of the present invention is to provide a hand tool for
tensioning and severing straps which will produce uniformity of
tension in successively-applied straps, regardless of how the tool
is held in the hand. A consideration of the forces exerted on the
different parts of the tool illustrated in the present drawings and
described above will reveal that this objective has been
accomplished. Indeed applicants know of no prior hand-operated
tool, for tensioning and automatically severing straps, having this
highly-desirable characteristic. In the prior hand-operated tools
known to applicants, the tension in the strap, at the time of its
severance, will vary, depending upon where the finger force is
applied to the actuating handle or handles and depending upon
variations in the compression in the handle return springs at the
time strap severance takes place. Neither of these deficiencies
exists in the tool of the present invention. This will be
understood from the above description and illustrations and when
particular regard is given to the forces acting on the lever link
100. It will be seen that the force applied by the pin 101
corresponds to strap tension, and it will also be seen that, for a
particular adjustment of the knob 162, strap severance will occur
every time the force exerted by the pin 103 on the link plates 104
and 105 reaches a particular level. It will also be seen that the
forces on the pins 101 and 103 result solely from the actuating
force applied to the pin 99, and the sum of the forces on the pins
101 and 103 is equal to the force applied to pin 99. Since there is
a fixed or constant dimensional relationship between all three of
these pins, the force relationship between them is also fixed. For
example, with the pin 99 located midway between the pins 101 and
103, as is the case in the embodiment of the invention here shown,
the force on the pin 101 is equal to the force on the pin 103, and
each force will be one-half of the force on pin 99. Therefore, the
strap tension is always the same at strap severance for a
particular setting of the adjustment knob 162, and the strap
tension at cut-off is not dependent on the source of actuating
force applied through the pin 99. It is equally true, therefore,
that the strap tension at which cut-off occurs will not be changed
by the application of finger force at different elevations on the
trigger or actuating handle 85, nor by any force variations that
may be produced by means, such as the return spring 33, for
returning the trigger to its original position.
The other objects first stated above are also attained by the tool
of the present invention. The tool may be relatively light in
weight, it is comfortable and convenient to use, and binding straps
may be applied to bundles of wire or the like, at uniform selected
tensions, rapidly and easily with the use of the tool. Furthermore,
the tool is substantially foolproof, relatively simple of
construction, very durable, and relatively easy to manufacture.
Indeed, the durability of the tool is enchanced by the fact that
the tool inherently tends to avoid hammering the strap-cutting
parts of the tool against other parts thereof as the strap severing
is completed. On the contrary, although the blade 76 moves very
rapidly during the cutting stroke, it will be appreciated that
during the fraction of a second before severing of the tensioned
strap end 55 is complete, the tensioned strap will begin to part,
thereby permitting the tension rod 41 to move slightly to the right
as viewed in the figures. This movement instantaneously reduces the
forces on the pins 101 and 103, and thus on the lever arm 70 and
the blade, and tends to reduce or avoid hammering effects on the
lever arm and blade as they reach the end of their cutting
stroke.
While the invention has been illustrated and described with respect
to a preferred embodiment thereof, with certain variations, it is
to be understood that various changes and modifications may be made
therein without departing from the inventive concept underlying the
invention. Therefore, the invention is not to be limited, except as
is necessary, by the prior art and the scope of the appended
claims.
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