Note: Descriptions are shown in the official language in which they were submitted.
20(~830~
DRUM FOR R~CEIVING A ROPE
lo This invention relates to a drum for receiving a rope
having the features of the gensric notion of claim l.
Such drums are used in particular for ropes which are
part of an operating and/or equilibration means for a
door blade, especially of the type which is moved
overhead and consists of successive members articulated
to one another in the moving direction.
Depending on the force-distance-characteristic of the
procsss of motion to be carried out and, in particular,
on that one of a spring provided for equilibration,
such drums provided with guide grooves for the rope are
formed regularly cylindrically, conically or so as to
change from regularly cylindrical shape into conical
shape, a progressive increase in the diameter being
possible to be provided within the scope of the conical
shape so that a corresponding line of spring force can
be compensated by the differently increasing rope
wrapping diameter.
Such drums are known, namely manufactured in the form
of cast parts, especially die-cast parts, also of light
metal alloys. Such drums are therefore complicated and
expensive in manufacturing and their weight is still
relatively high, even if made of cast aluminium.
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Accordingly, the invention is based on the object of
providing a drum of the type described above which is
less complicated and expensive to manufacture and has,
in case, less weight than the one according to prior
art.
Starting from a drum having the features of the generic
notion of claim l, this object is colved by the
lo characterizing features thereof.
According to the invention at least the drum casing
wall with the guide groov0s for the rope is made of
sheet metal which is worked without cutting, namely in
a metal spinning process raquiring flow deformation of
the sheet metal. In a preferred embodiment this results
in a substantially undulated shape in the area of the
drum casing wall in a longitudinal section through the
drum axis, the troughs appearing at the casing wall
outer surface having the cross section of the guide
groove and the troughs present at the casing wall inner
surface facing towards the drum axis being located
radially oppoæite to the raised zones between the
adjacent groove windings occuring at the outer surface.
In a particularly preferred embodiment at lea~t the
drum casing wall is made of sheet metal which
sub6tantially plane shape is changed into the casing
wall shape by way of flow dsformation. In this on both
3e frontside edges of the drum casing wall radially
projecting integrally formed collars may be provided.
Here it is especially preferred to form one of the drum
frontside walls integrally with the drum casing wall,
respectively the adjoining collar. In this case the
proce~s is such that the sheet metal in the portion of
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this drum frentside wall, re~pectively in a radially
inner portion is supported in the machine tool and put
into rotation around the axis of the drum to be
manufactured preferably through this supporting
engagement. It is basically possible to device the
forming tool engaging at the sheet metal so that it
rotates around this drum axis and to keep the sheet
metal stationary. Preferablyr however, the sheet metal
is put into rotation, whereas at least the forming tool
lo engaging at the outer surface of the dxum casing wall
to be manufactured does not rotate around the drum
axis. The direct engagement of such a tool, between
which and the sheet metal a relative movement takes
place, is normally effected via one or more roller
bodies in order to avoid any frictional angagement.
The forming tool at lea~t has a tool part which engages
at the outer surface of the drum casing wall to be
manufactured. Depending on the sheet metal material,
required accuracy, manufacturing speed, machine
equipment of the forming machine and the like, it may
be advantageous or necessary at least in the course of
the formation of the guide grooves that the sheet metal
in the portion of the drum casing wall is received
between two tool parts which are adapted to one another
or are at least correspondingly profiled with respect
to the positive formation of the guide grooves on the
outer surface and their negative formation on the inner
surface of ths drum casing wall. There can be provided,
for example, a mould or matrix having the negative
profile of the guide groove on its casing outer surface
and being arranged coaxially with the drum axi~ and
adapted to the inner cylinder and/or conical shape
against which the sheat metal is moved by mean~ of a
pressing tool part engaging at the outer surface and is
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formed or shaped following the course of the profile of
the guide groove.
In this the pressing tool part effects a feed
corresponding to the pitch of the screw-shaped guide
groove in the direction of the drum axis, namely
responsive to the relative speed between sheet metal
an~ forming tool. The mould arranged coaxially wi~h the
drum axis can rotate or revolve together with the sheet
metal at the same rotational speed. Still another
embodiment can work with a set of rollers consisting of
profiled rollers engaging at the outer and inner
surfaces of the drum casing wall which are displaceable
towards each other and in their totality are ~orcibly
guided with a motional component in the direction of
the drum axis following the pitch of the guide groove
such that the sheet metal portion of the drum casing
wall respectively received therebetween is shaped
together with the guide groove after the matching of
pitch and peripheral speed. Instead of roller~, for
example, which only have the profile of one windin~,
respectively the negative profile of the web formed
therebetween such rollers may be used which have two or
more guide groove web profiles, respectively their
negative formations succeeding one another in the axial
direction of the drum, the feeding speed and the
relationship of the drum and roller diameter being
matched correspondingly. According to another
embodiment there may be provided plural rollers
succeeding one another in the a~ial direction which
correspondingly applies also to the cooperation between
rollers and mould. Furthsrmore, one and the same
forming tool or tool part can be successively guided
multiple times along the drum casing wall engaging at
the same.
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Furthermore, it may be advantageous or necessary to
effect the deformation of a sheet metal plate
especially one which is substantially plane - into the
drum shape by means of a separate pre-working tool with
which the shest metal is first changed into the shape
of the regularly cylindrical, conical or succe~sivsly
circular-conical drum casing wall, while thereafter the
guide groove and, in case, the frontside collars and
lo the like are formed in one process or separately in a
subsequent process, the frontside collars being able to
be formed also in the first spinning process. The
contour of the regularly cylindrical, respectively
conical wall of the drum casing preferably corresponds
to approximately the longitudinal section connecting
line in the outer, inner or intermediate peripheral
portion of the wave form of the drum casing wall guide
groove progression. In such a successive manufacturing
process of the drum wall contoux first and the
engraving of the guide groove next different relative
speeds may be provided, for example, first at a high
relative speed, respectivelr revolving speed of the
sheet metal part the shaping of the drum casing wall
contour and subsequently at a low speed the engraving
of the guide groove.
In such a case the forming tool part-portion engraving
the guide groove can be deviced irrespective of any
coarse shaping of the sheet metal taking place in the
axial direction, namely up to the development of
profiled rollers, one of which being arranged coaxially
with the drum axis and provided on the outer casing
surface thereof with the negative profile of the guide
groove progression and the other one, which engages the
pre-shaped sheet metal from the radial outside, having
Z0~8~0~
the guide groove web profile appearing at the outsr
surface of the drum casing wall, namely formed with the
drum radius so that a motional component of ~uch a
groove engraving mould member directed towards the drum
axis is dispensable. If it is talked about a profile
here, then in terms of a line following the profile
surface in the longitudinal section direction.
Of course, starting from this pre-contoured roller
construction, embossing work to be carried out in order
to form the guide grooves can be done with other
forming tools as described above, for example with the
aid of a set of rollers.
Starting from the idea of such a regularly cylindrical
and/or conical contour of the drum casing wall one may
imagine as a starting point for the drum manufacturing
a tube of sheet metal which i5 formed seamless or
longitudinally or spirally welded, preferably in a
fusion welding process using a laser beam. Not only can
such a tube be embossed or engraved with respect to the
forming of the groove progression per S9, but in the
course of thi.s working ~tep it may be formed into
conical or partly conical shape with or without
progressiYe diameter and it may be al~o provided with
frontside collars delimiting the reception area of the
rope reception guided in a single layer and ~erving for
the attachment of frontside walls.
In the course of manufacturing the drum by means of
metal spinning along with a front wall integrally
joining the drum casing wall or with the starting shape
of a tube a tool engaging at the inner upper surface of
the casing can be removed without any problems through
the open frontsides, respectively one of them. This
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also applies in case of a mould or matrix arranged
coaxially with the drum axis which by virtue of the
spiral course of the guide groove can be turned out of
the finished former, a corresponding clearance being
existing because of the unavoidable residual
backspringing of the sheet metal with re~pect to the
mould or matrix.
This and other preferred embodiments of the invention
result from the subclaims, particularly with reference
to the examples which are reflected in the drawings and
which subsequent description more clearly explains the
invention. There is shown in:
Figure 1 a ~ide view of an embodiment of a drum with a
drum frontside wall integrally joining the
drum casing wall, in the upper hal~ as a
longitudinal sectional view through the drum
axis, namely merely in respectof the contour
of the sectioned wall portions;
Figure 2 a partial sectional view of the connection
between the separate frontside wall and the
adjoinin~ side edge portion of the drum
casing wall corresponding to Figure 1 in a
modified form;
Figure 3 a partial sectional Yiew corresponding to
Figure 2 in another modified form.
The three embodiments reflected in the drawings are
respectively based on a drum having a basical structure
such as shown in Figure 1, i.e. a drum with which one
2008~
of the frontside walls is formed integrally with the
drum casing wall. This corresponds to the manufacturing
of a drum from an approximately plane &heet metal disk
by the engagement of a forming or pressing tool which
from this frontside i8 guided in the axial direction
towards the other frontside collar of the drum, namely
taking into consideration the course of the guide
groove to be formed in the portion of the drum casing
wall.
The drum which is altogether designated by reference
numeral 1 has a drum casing wall 2 which towards the
left side of the drawing integrally changes into a
frontside wall 3, whereas at the axially opposite side
end it is clo~ed by separate frontside wall 4 not
integral with the drum casing wall 2.
The frontside wall 3 formed integrally with the casing
wall 2 has an axle hub 5 which is formed as one part
with the frontside wall 3 and can be co-~haped in the
course of the metal spinning process. This is possible,
for example, in that a plane or flat sheet metal disk
is gripped by a turning tool in the mouth portion
surrounded by the axle hub 5, whereupon a forming tool
is moved in the axial direction from the gripping or
clamping position thereby 3haping the regularly
cylindrical wall of the axle hub 5. This is followed
without spinning deformation by the frontside wall 3,
whereupon the further shaping of the casing takes
place. For this purpose a mould or matrix is providsd
which in a manner not shown in the drawings supports
the frontside wall 3 from the inside of the drum and
has on its casing outer surface the negatiYe contour
appearing by virtue of the course of the guide groove
at the inner side of the casing wall ~, as will be more
2~08
clearly explained later. A pressing or forming tool
engaging at the sheet metal disk is then guided so that
the course of tha guide gxoove results, namely
followin~ the contour of the outer surface of the drum
casing wall 2 and, under consideration of the pitch of
the course of the guide groove with radial and axial
pressure, the matrix contour. As can be seen from
Figure 1, al50 the separate frontside wall of sheet
metal can be provided with a hub extension 6 which, in
lo case, can also be integrally formed at the frontside
wall 4 by means of metal spinning. The axle hub 5 is
penetrated by a screw 7 inserted in a bore provided in
a hollow axle (not shown) of a shaft carrying an
equilibration torsional spring so that the drum is
lS axially and unrotatably connected to the hollow hub.
Similar screw means can be provided also in the zone of
the hub extension 6. The axle hub 5 and/or hub
extension 6 can also be provided as separate parts,
e.g. of pre~sure diecaæting, to be interconnected with
the sheet metal, above all when high torques are to be
transmitted.
As ~an be seen from the lower half of the side view in
Figure 1 and ~rom the sectional view above the drum
a~is 11, the drum ~asing wall 2 i8 provided with a
screw-shaped guide groove 8 which groove for receiving
a rope (not ~hown) appears at the outer surface 9 of
the drum casing wall 2. The guide groove 8 is impressed
in the sheet metal of the drum casing wall 2 under flow
deformation so that the wall 2, viewed in longitudinal
section, is given an undulated shape such as can be
seen from the upper half of Figure 1, namely in a
material and weight-saving manner. The troughs 10
appearing at the outer surface of the wall 2 form the
receiving portions of the guide groove windings for the
8~
engagement of the rope not shown, whereas, when viewed
from the direction of the drum axis 11, the inner
surface 12 of the drum casing wall 2 has trough~ 13
which, when viewed in the radial direction, are located
opposite to the zones 14 which are raised with regard
to the outer surface 9 and which separate the troughs
10 of the guide groove windin~s from one another. The
troughs 10 and raised zones 14, which can be seen from
the upper cross-sectional view of Figure 1, run into
o one another in the course of the progression of the
guide grooves to from closed circumferential portions.
Viewing to the left, the drum casing wall 2 i~ provided
on the side edge 17 adjoining the integrally formed
frontside wall 3 with a radially projecting collar 15
which correspondingly laterally delimits the rope
receiving portion of the drum casing wall 2 and forms
the integral transition between the casing wall 2 and
frontside wall 3. The side edge 18 located oppositely
when viewed in the axial direction is also formed as a
radially outwardly projecting collor 16 which æarves
for tha fi~ing of the separately ~ormed frontsida wall
4. In the embodiment according to Figure 1 this
front3ide wall 4 is rigidly connected to the collar 16
of the side edge 18 of the drum casing wall 2 by means
of spot weldings 19 distributed over the circumference.
In this manner the drum is supported with both
frontsides on the hollow shaft not shown.
In Figure 2 there is shown a partial section of the
upper right connecting portion between the drum casing
wall 2 and the separate fxontside wall 4, wherein a
connectin~ method other than welding is realized. In
the portion of the side edge of the drum ca~ing wall 2
the radially proje~ting collar 16` is performed longer
20(~
11
and, after applying the separate frontside 4, iæ beaded
around the circumferential edge 21 thereof. The bead is
designated by reference numeral 20. The bead may be
carried out continuously throughout the circumference
or, however, in ~eparate ~ections distributed over the
circumference.
Figure 3 reflects a partial section corresponding to
Figure 2 wherein the connection of the side edge 18 to
ths circumferential edge 21` o~ the separate frontæide
wall 4 with the aid of circumferentially distributed
pressure joints 22~is realized. In the embodiment shown
the pressure joints 22 are made into the collar 16`` of
the side edge 18 of the drum casing wall 2 from the
circumferential edge 21`of the frontside wall 4 so that
portions are produced which are projecting when viewed
towards the axial drum center. In order to not obstruct
the ascent and descent of the rope the circumferential
edge 21` of the frontside wall 4 and the collar 16``
are axially slightly outwardly bent when viewed from
the axial center of the drum. The collar 16``is
additionally provided with a centering edge projecting
in the axial direction for receiving the frontside wall
4.
The drum reflected in total in Figure 1 serves for
receiving a rope which is fixed with its end descending
from the drum to a doorblads which is moved overhead in
order to provide with the aid of a torsion spring
positively engaging a hollow shaft unrotatably
connected to the drum an equlibration meanæ for the
doorblade such as known in prior art. For the
compensation of the force-di~tance-characteristic of
the torsion spring the drum according to the present
embodiment is formed regularly cylindrically in a first
( clln~h connec~ ion)
12
portion 23 which is followed by a conical portion 24
which, viewed from the regularly cylindrical portion
23, is formed with progressively increasing diameter.
