APPARATUS FOR TENSIONING AND LOCKING HOOPING BANDS

DISPOSITIF POUR TENDRE ET ACCOUPLER DES BANDES DE CERCLAGE

English Abstract

ABSTRACT OF THE DISCLOSURE
The primary thrust drive for a punch and die set
which presses together two superimposed portions of the
band to be locked utilizes the mechanical advantage afforded
by a symmetrical angle lever pair. The arms of the levers
are turned about a pair of pinions by a pneumatic piston
drive. At the end of the other arms is a pressure roller
which rides on a pressure surface of a pressure plate to
convert the rotation movement of the angle levers to an
outward linear movement on the pressure plate towards the
pinions. The pressure plate carries the die. The pressure
surface upon which each of the rollers acts is made to have
a cylindrical curvature away from the roller. This has the
effect of making more linear the characteristic increase
of the mechanical advantage of the toggle arrangement as
a function of the outward travel of the pressure plate and
thereby making the adjustment of the die travel less
critical.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for locking two superimposed portions
of a strap by deforming the portions, comprising a base plate with
a punch mounted therein; a casing fixed to said base plate; a
pressure plate movably mounted for guided movement toward and
away from said punch, said pressure plate having a pressure
surface facing away from said punch and a die surface facing
toward said punch; a die fixedly mounted on said die surface and
facing said punch; and force means mounted in said casing and
operatively coupled to said pressure plate by toggle linkage means,
said force means having a reciprocating member, said linkage means
having a first link which is pivotally coupled intermediate its
ends to said casing and pivotally coupled at one end to said
reciprocating member, the other end of said first link being in
sliding contact with said pressure surface; said pressure surface
having a first concave cylindrical portion in the area of sliding
contact with said other end of said first link.
2. An apparatus according to claim 1, wherein said
linkage means has a second link which is pivotally coupled
intermediate its ends to said casing and pivotally coupled at one
of its ends to said reciprocating member, the other end of said
second link being in sliding contact with said pressure surface;
said pressure surface having a second concave cylindrical portion
in the area of sliding contact with said other end of said second
link.
3. An apparatus according to claim 2, wherein said
links are symmetrically located relative to a central axis
extending in the direction of pressure plate movement and are
oppositely directed.
4. An apparatus according to claim 1, wherein said first
link has a pressure roller rotatably mounted at said other end for
contacting said pressure surface.

5. An apparatus according to claim 1, wherein said
pressure plate has at least one guide bore and said base plate
has at least one guide means extending therefrom which is
received in said guide bore to guide said pressure plate.
6. An apparatus according to claim 1, wherein a cutting
blade is releasably mounted in said pressure plate, said pressure
plate having a slot formed therein opening on said die surface and
being at least partially covered by said die; and wherein a pin
extends through said blade and into said slot between said
pressure plate and die.
7. An apparatus according to claim 1, wherein said first
link comprises two fixedly coupled, angularly oriented arms, and
is pivotally coupled to said casing adjacent the juncture of said
arms.

Description

3333
The invention relates to an apparatus for locking band
hoops on packages by permanent deformation oE two superimposed
portions of a flexible hooping band. rrhe deformation of
the portions is brought about by press:ing down a die arrangcd
in raisable and lowerable manner over the portions. The
bottom of the die is fixed to a pressure plate which is
guided in the casing of the apparatus and toward a punch
mounted in a base plate of the apparatus and positioned below ~-
the portions. ;
There are fundamentally two groups of known apparatusfor locking band hoops. In the first group, locking is
accomplished by means ~ a lockiny sleeve w}licll is placed over
the superimposed portions of the hooping band and is deformed
together with the band portions to form a non-detachable
connection. In the second group, which apparatus is used mainly
for locking flexible metallic bands or strips, locking
takes place without a sleeve, i.e. through reciprocal
permanent deformation of the superimposed portions of the
hooping band.
In the case of the second group of apparatus, the forces
to be applied for deforming the superimposcd portions of
the hooping band are very large because a non-detachable
connection has to be produced without using a locking sleeve.
To this end, the band portions are placed between a punch
mounted in the base plate of the apparatus and a raisablc
and lowerable die spaced above the punch. The die is pressed
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- ~ ~ 0~3;~33
down with great force onto the band portions either manually
or by means of a power drive until the permanent deformation
of the band portions necessary for the non-detachable
connection is achieved.
In order to obtain a permanent non-cletachable connection
between the band portions, it is important that the movable
die is precisely aligned with the punch mounted in the base
plate in order to bring about a perfect cooperation between
the protuberances and depressions arranged in both these
tools. ~lowever, this is not sufficient for obtaining a
suitable connection if the force applied is insufficient.
In known apparatus of this type, the necessary force is
provided through force transmission lirlkages, such as toggle
linkages. When such transmission linkages are used within
a small lifting or stroke range, rapidly increasing forces
are exerted. If the stroke travel is set too far, the resulting
excessive force can lead to the destruction of the apparatus
during the locking process. If the stroke travel setting
is made too short, the necessary minimum deEormation for
the locking process is not obtained.
The present invention provides
an apparatus of the type indicated hereinbefore that tlle value
of the pressure force is varying in an uniform manner as a
function of the stroke, and the lateral forces acting on
the die are absorbed in the immediate vicinity thereo and
conducted into the base plate.

0~3 333
According to the present invention there is provided
an apparatus for locking band hoops on packages by permanent '
deformation of two superimposed portions of a flexible hooping
band, said apparatus being of the type b~ which the deformation
of the band portions is brought about by pressing down a die
arran~ed in raisable and lowerable manner over the portions,
A wherein the improvement comprises, a punch mounted in a base
¦ plate of said apparatus and positioned below said portions, a
die facing said punch, and a pressure plate to which the bottom
of said die is fixed, said pressure plate being guided in a
~ casing of said apparatus toward said punch, the top of said
; pressure plate being constructed as a pressure surface for the
end of a first arm of two angle levers mounted with a horizontal
spindle in said casing, the force Eor operating said toggle
levers being applied to a second arm of said levers rigidly
connected to said first levers at said spindle.
According to the invention, therefore the top of the
pressure plate is constructed as a pressure surface for the end
of a first arm of two toggle levers mounted with a horizontal
spindle in the casing, whereby the force for operating the
toggle levers is applied.
The present invention will be further illustrated by `-
way of the accompanying drawings in which:
Fig. 1 is a side view of an apparatus for tensioning
and locking band hoops, with juxtaposed locking and tensioning
parts;
Fig. 2 is a vertical section through the locking part
3 of the apparatus of Fig. 1.
The apparatus shown in Fig. l for tensioning and lock~
ing band hoops or straps has a base plate above ~hich is
positioned a band channel, accessible from one side, for insert-
ing not shown superimposed band portions of a flexible hooping
hand. In base plate l there is mounted a punch 3 which faces a

3.~3~
movable die 4 fixed to a primary thrust drive mechanism. Punch
3 and die 4 are deformed at their pressure suxiaces in such a
~ that on pressing do~ of the die 4, the superimposed band
¦ portions are permanently deformed to give a permanent connection.
S A casing 5 in which is fitted a primary thrust drive
mechanism for the die 4, as will be described hereinafter
¦ relative to Fig. 2, and which is connected to base plate 1, is
positioned above band channel 2. A further secondary thrust
drive mechanism with a thrust rod 6 is fittet in the casing 5
alongside the primary thrust drive mechanism. Thrust rod 6 is
; articulated via a swivel joint 7 to a tensioning housing 8 which
is in turn mounted via a swivel joint 9 on casing 5. Thus,
~ tensioning housing 8 can be pivoted about toggle joint 9 by
;i means of the associated secondary thrust drive mechanism via
thrust rod 6.
In the tensioning housing 8 there is pivotably mounted
a tensioning roller 10 which is operable either manually or, as
shown in Fig. 1, by a motor drive 11, e.g. an electric or
pneumatic motor. For placing the hooping band in band channel
2, the tensioning housing 8 with the tensioning roller 10 is
raised by the thrust rod 6. The die 4 is raised by its assoc-
iated primary thrust drive mechanism. When the hooping band is
inserted, the tensioning housing 8 is lowered and the tensioning
roller 10 is pressed onto the hooping band and rotated by the
drive 11 for tensioning.
A handle 12 is ~ixed -to the casing 5. On the handle
are provided two operating levers 13, 14. Operating lever 13 is
used to raise and lower tensioning roller 10 and tensioning
housing 8, while the band is tensioned by lever 14. The primary
thrust drive mechanism of die 4 is operated automatically or by
a not shown button on the back of casing 5.
Fig. 2 shows a section through the casing 5. Punch 3
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33~
is mounted on the base plate 1 by means of screws 15. Opposite
punch 3 the die 4 is fixed to a pressure plate 16 by means of
screws 17. Screws 20 are used to fix a cam 19 to the surface
j 18 of the pressure plate 16, the cam having a T-shaped profile.
Two two-armed angles or toggle levers 22 with a horizontal
spindle 23 are pivoted in lower part 21 of the casing 5. Each
~ angle lever 22 has a smaller first arm 24 and a longer second
; arm 25. ~t the free end of the first arm 24 of the two angle
levers 22 there is mounted in rotary manner a pressure roller
3 lo 26 whose spindle projects into a cam 19.
The free end of the second arm 25 is connected by means ;
of a swivel joint 27 with a connecting arm 28, which in turn is ::
. connected via a swivel joint 29 to a bearing bracket 30. Bearin~
1 bracket 30 is connected to a piston 31 which is guided in movable
~ manner in the upper part 32 of casing 5. At the transition from
upper part 32 into cover part 33 a feed line 34 is provided by
i means of which a fluid pressure medium can be supplied to the
j primary thrust piston drive formed by components 30 to 33. As
the thrust piston drive 30 to 33 is single-acting, a compression
~0 spring 35 is provided on the bottom of piston 31 and supported
on a shoulder 36 within lower part 21 when the pressure on the
top of piston 31 is relieved, the spring 35 raises the thrust
piston drive and consequently the pressure plate 16 with die 4.
If a pressure medium, e~g. compressed air, is supplied
by feed line 34 to the thrust piston drive 30 to 33, angle
levers 22 are pivoted as a result of the movement of piston
31 so that the pressure plate 16 is lowered. Pressure rollers
25 hereby roll on the surface 18 of pressure plate 16 and
produce a corresponding pressure force on die 4.
. ~
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q3~33
, . ,
If it is desired to control the degree of th~
development of the pressure force with the travel, this can
be done with non-planar surface confic3urations within tlle
; roller path of the pressure rollers 26. The pressure surface
18 has concave cylindrical portions against which the
pressure rollers 26 act and the axis of which is parallel
to the axis of the pressure rollers. Due to these curvatures
of the pressure surface, the pressure force is made more
uniform as a function of movement of the pressure plate 16,
l~ i.e. as a function of the stroke.
A cutting blade 38 is fixed by mcans of a bolt 39 to
the bottom of prcssure plate 16. Bolt 39, e.g. a spring
cotter is located in a slot 40 and is prevented from falling
out by the die 4. The cutting blade 38 may be readily
replaced when it has suffered a certain degree of wear by
merely removing first the die 4.
Guide means 42 fixed in the base plate and projecting
into corresponding bores of the pressure plate 16 are
provided for the precise alignment of the plate 16 with
~0 the die 4 relative to the punch 3.