U.S. patent application number 11/124737 was filed with the patent office on 2005-12-01 for actuating means able to be activated by fluid action.
This patent application is currently assigned to Festo AG & Co.. Invention is credited to Lorenz, Bernd, Muller, Alexander, Schantze, Achim.
Application Number | 20050265870 11/124737 |
Document ID | / |
Family ID | 34925125 |
Filed Date | 2005-12-01 |
United States Patent
Application |
20050265870 |
Kind Code |
A1 |
Schantze, Achim ; et
al. |
December 1, 2005 |
Actuating means able to be activated by fluid action
Abstract
An actuating means adapted for fluid activation has a
contractile hose terminally secured by clamping on at least one
head piece. The contractile hose fits into an annular clamping gap
or nip, whose wall bears saw tooth serrations, the saw tooth
serrated areas being so arranged that their teeth are radially
opposite each other and arranged in pairs each at the same level.
The outer saw tooth serrated area is located on a compression
sleeve, which is radially pressed to join it with the hose end
section surrounded by it.
Inventors: |
Schantze, Achim; (Sulz a.N.,
DE) ; Muller, Alexander; (Altbach, DE) ;
Lorenz, Bernd; (Baltmannsweiler, DE) |
Correspondence
Address: |
HOFFMANN & BARON, LLP
6900 JERICHO TURNPIKE
SYOSSET
NY
11791
US
|
Assignee: |
Festo AG & Co.
|
Family ID: |
34925125 |
Appl. No.: |
11/124737 |
Filed: |
May 9, 2005 |
Current U.S.
Class: |
417/479 ;
417/474 |
Current CPC
Class: |
F15B 15/103
20130101 |
Class at
Publication: |
417/479 ;
417/474 |
International
Class: |
F04B 043/08; F04B
043/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2004 |
EP |
04 012 388.7 |
Claims
1. An actuating means able to be activated by fluid action
comprising a contractile hose, extending between two head pieces
and adapted, under fluid action in the space within it, to undergo
radial expansion while simultaneously exerting axial tension forces
on the head pieces involving a tendency to draw same together, the
contractile hose having a hose body of a material with rubber
elastic properties and a strand structure embedded in the wall of
the hose body with a coaxial arrangement, said contractile hose
being secured to at least one head piece by having an end section
thereof clamped in an annular clamping gap, which is defined by the
outer periphery of an inner head piece part extending axially into
the contractile hose and the inner periphery of an outer head piece
part coaxially surrounding the contractile hose at the level of the
inner head piece part, wherein the outer periphery of the inner
head piece part and the inner periphery of the outer head piece
part have saw tooth serrated areas, whose direction of serration is
in the axial direction, the flat tooth flanks facing the clamping
gap opening with the contractile hose extending through it, the two
saw tooth serrated areas are so arranged that their teeth, lying at
the same axial level, are respectively radially opposite each other
in pairs and the outer head piece part is designed in the form of a
compression sleeve radially compressed, with radial deformation,
with the hose end section surrounded by it.
2. The actuating means as set forth in claim 1, wherein prior to
such radial pressing the compression sleeve is able to be slipped
from the front side opposite to the axial clamping gap opening
coaxially onto the inner head piece part and owing to mutually
engaging abutment faces provided on the one hand on the compression
sleeve and on the other hand on the inner head piece part an axial
slipping on position of the compression sleeve is set, in which the
teeth of the two saw tooth serrated areas are opposite to each
other in pairs at the same axial level.
3. The actuating means as set forth in claim 2, wherein abutment
faces provided for setting the slipping on position possess an
annular configuration.
4. The actuating means as set forth in claim 1, wherein the
compression sleeve possesses a radially inwardly protruding annular
projection, which during radial pressing fits into a radially open
locating groove in the inner head piece part.
5. The actuating means as set forth in claim 4, wherein prior to
such radial pressing the compression sleeve is able to be slipped
from the front side opposite to the axial clamping gap opening
coaxially onto the inner head piece part and owing to mutually
engaging abutment faces provided on the one hand on the compression
sleeve and on the other hand on the inner head piece part an axial
slipping on position of the compression sleeve is set, in which the
teeth of the two saw tooth serrated areas are opposite to each
other in pairs at the same axial level and wherein the abutment
faces are constituted by respectively one flank of the annular
projection and the locating groove.
6. The actuating means as set forth in claim 1, wherein at the
front side axially opposite to the axial clamping gap opening the
clamping gap merges with an annular gap extending in a radially
outward direction and defined between the inner head piece part and
the compression sleeve, into which gap hose body material may be
displaced during pressing.
7. The actuating means as set forth in claim 1, wherein the
resulting envelope lines running in the longitudinal direction and
radially opposite to each other, of the two saw tooth serrated
areas extend in parallelism to each other.
8. The actuating means as set forth in claim 1, wherein the two saw
tooth serrated areas widen conically toward the axial clamping gap
opening, which has the contractile hose extending through it.
9. The actuating means as set forth in claim 1, wherein the radial
distance apart between the envelope faces defined by the tooth tips
of the two saw tooth serrated areas is equal to at least the radial
dimensions of the strand structure embedded in the wall of the hose
body.
10. The actuating means as set forth in claim 1, wherein the rear
end section, directly adjoining the axial clamping gap opening, of
the clamping gap is free of teeth and has a smooth surface.
11. The actuating means as set forth in claim 1, wherein the height
of the teeth of the saw tooth serrated areas is approximately equal
to one quarter of the wall thickness of the hose body.
12. The actuating means as set forth in claim 1, wherein one tooth
is provided per millimeter length of the saw tooth serrated
areas.
13. The actuating means as set forth in claim 1, wherein the strand
structure comprises strands arranged in a cross over pattern.
14. The actuating means as set forth in claim 1, wherein the strand
structure comprises two strand groups arranged in a cross over
configuration with flexurally bending strands extending alongside
each other and with the same longitudinal orientation within a
strand group, such strand groups being constantly held at a radial
distance apart from each other by the material of the hose
body.
15. The actuating means as set forth in claim 1, wherein the
contractile hose is secured at both ends as set forth in claim 1 at
a head piece.
Description
BACKGROUND OF THE INVENTION.
[0001] The invention relates to an actuating means able to be
activated by fluid action comprising a contractile hose, extending
between two head pieces and adapted, under fluid action in the
space within it, to undergo radial expansion while simultaneously
exerting axial tension forces on the head pieces involving a
tendency to draw same together, the contractile hose having a hose
body of a material with rubber elastic properties and a strand
structure embedded in the wall of the hose body with a coaxial
arrangement, said contractile hose being secured to at least one
head piece by having an end section thereof clamped in an annular
clamping gap, which is defined by the outer periphery of an inner
head piece part extending axially into the contractile hose and the
inner periphery of an outer head piece part coaxially surrounding
the contractile hose at the level of the inner head piece part.
THE PRIOR ART.
[0002] In the case of an actuating means of this type disclosed in
the patent publication WO 00/61952 A1 a contractile hose, composed
of a rubber elastic hose body and a strand structure embedded in
the hose body has both its hose end sections secured in a
respective head piece. The head pieces comprise an inner head piece
part extending into the contractile hose and an outer head piece
part surrounding the associated hose end section, such outer head
piece part being designed like a union nut and being screwed onto
the inner head piece part. Between the two parts an annular
clamping gap is defined, in which the associated hose end section
is clamped by compression. The pressing operation occurs because
there is the axial screwing of the two parts of the head piece and
a conical shape of the clamping gap or nip.
[0003] For the activation of the actuating means the inner space of
the contractile hose is filled with a pressure medium under a
certain actuating pressure. This causes a radial expansion of the
contractile hose resulting in a tendency to axially contract so
that tension forces are applied to the head pieces, whose action on
the head pieces involves moving same together. It is in this manner
that external structures or, respectively, components, which are
fixed to the head pieces, may be braced together and/or shifted in
relation to one another.
[0004] The clamping connection between the contractile hose and the
head pieces has turned out to be problematical more especially on
the occurrence of substantial tension forces. Although the clamping
face of one of the clamping units is provided with several
projections, which are able to bite into the material of the
contractile hose, there is danger of the contractile hose's being
pulled out of the clamping gap.
[0005] In order to meet this problem there has already been a
proposal in the German patent publication 10,034,389 C2 to design
the portions, which lie against the hose end sections, of the inner
head piece part and of the outer head piece part so that same may
be moved in relation to each other axially to a limited extent so
that on activation of the actuating means there is an entraining
effect which results in a reduction in the width of the clamping
gap and therefore an increase in the surface pressure. In order to
optimize the entraining effect the faces engaging the hose body may
have a finely divided surface structure, as for example a groove
structure, or also have a finely divided structure with punctuate
mounds and pits. This design does however involve increased design
complexity, something which renders manufacture more costly.
SHORT SUMMARY OF THE INVENTION
[0006] One object of the invention is to create an actuating means
which despite a simple structure ensures a reliable connection
between the contractile hose and the head piece even on the
occurrence of high tensile forces.
[0007] In order to achieve these and/or other objects appearing
from the present specification, claims and drawings, in the present
invention the outer periphery of the inner head piece part and the
inner periphery of the outer head piece part have saw tooth
serrated areas, whose direction of serration is in the axial
direction, the flat tooth flanks facing the clamping gap opening
with the contractile hose extending through it, the two saw tooth
serrated areas are so arranged that their teeth, lying at the same
axial level, are respectively radially opposite each other in pairs
with their tips opposite each other and the outer head piece part
is designed in the form of a compression sleeve radially
compressed, with radial deformation, with the hose end section
surrounded by it.
[0008] Owing to the saw tooth serrated areas it is possible for
both the inner head piece part and also the outer head piece part
to bite into the elastic material of the hose body so that there is
a powerful interlocking effect, so that even in the case of a high
tension load a drawing of the contractile hose out of the
respective head piece is prevented. Since the teeth of the saw
tooth serrated areas lie at the same axial level, the strand
structure embedded in the hose body is essentially only subjected
to transverse compression and not to flexure so that despite
substantial compression a straight longitudinal alignment of the
strand structure may be ensured. Accordingly slipping of the
contractile hose out of the clamping gap is opposed. Furthermore
the danger of damage to the strand structure at the teeth tips is
minimized in this way. Damage to the material is furthermore
prevented by the preferably strictly radial pressing of the two
parts of the head piece so that during assembly axial relative
movement between the saw tooth serrated areas are prevented, which
could otherwise lead to damage of the elastic material of the hose
body.
[0009] Further advantageous developments of the invention are
defined in the claims.
[0010] The compression sleeve is preferably able to be slipped from
the opposite front side (opposite to the axial clamping gap
opening) coaxially on the inner head piece part prior to radial
pressing until owing to mutually cooperating abutment faces, an
axial relative position is reached in which the paired radial
alignment of teeth of the saw tooth serrated areas on the two sides
is attained. This renders possible high speed production without
involved adjustment operations.
[0011] It is an advantage if the compression sleeve has an annular,
radially inwardly extending positioning projection, which during
radial pressing fits into an annular, radially outwardly open
securing groove in the inner head piece part and in this manner
sets the desired axial relative position of the two parts of the
head piece.
[0012] At the front side axially opposite to the axial clamping gap
opening the clamping gap can merge with an annular gap extending
radially outward and defined between the inner part of head piece
and the compression sleeve, such gap rendering possible a
displacement without damage of the pressed hose body material.
[0013] The saw tooth serrated areas are preferably so arranged that
their envelope lines defined by the teeth tips extend in
parallelism to each other. This means that there is an even
pressing along the entire length of the clamped hose end section
avoiding local overloading.
[0014] A further advantage results from there being a form of the
two saw tooth serrated areas, and therefore of the clamping gap,
widening toward the axial clamping gap opening, through which the
contractile hose extends. The slope in relation to the longitudinal
axis of the head piece is of the order of 2 degrees. As has been
found this slope of the clamping gap, which is opposite to the
design of the said patent publication 00/61952 A1, leads to
substantially improved attachment conditions. This is more
especially the case when the diameter of the clamping gap at the
axial clamping gap opening is somewhat larger than the diameter of
the contractile hose in the middle section between the two head
pieces in the deactivated condition.
[0015] When the radial distance between the two envelope faces,
defined by the teeth tips, of the two saw tooth serrated areas is
at least as large as the radial dimensions of the strand structure
embedded in the wall of the hose body and is preferably even
somewhat larger, a particularly secure clamping of the contractile
hose without damage of the strand structure is possible.
[0016] The load on the contractile hose at the axial clamping gap
opening may be substantially reduced if the rear end section
located here, of the clamping gap, is free of teeth and smooth. The
saw tooth serrated area the comes to an end before reaching the
clamping gap opening.
[0017] It has been found to be particularly advantageous if the
height of the teeth of the saw tooth serrated areas is so selected
that it is approximately equal to 1/4 of the wall thickness of the
hose body.
[0018] Further advantageous developments and convenient forms of
the invention will be understood from the following detailed
descriptive disclosure of an embodiment thereof in conjunction with
the accompanying drawings.
LIST OF THE SEVERAL VIEWS OF THE FIGURES
[0019] FIG. 1 shows a preferred working example of the actuating
means in accordance with the invention, partly in longitudinal
section and in the pressed state of the compression sleeve.
[0020] FIG. 2 shows part of the end section, illustrated in the top
figure half of FIG. 1, of the actuating means on a larger
scale.
[0021] FIG. 3 represents the end section, illustrated in the top
half of FIG. 1, of the actuating means prior to pressing of the
compression sleeve, the compression sleeve being indicated in
chained lines prior to coaxial placement on the inner part of head
piece provided with the contractile hose.
DETAILED ACCOUNT OF WORKING EMBODIMENT OF THE INVENTION
[0022] The actuating means 1 illustrated in the drawings by way of
example comprises two first and second head pieces 2 and 3 arranged
at an axial distance apart, which are permanently connected
together by way of a linearly extending contractile hose 4. At
least in the deactivated state of the actuating means 1 the
contractile hose 4 preferably has an essentially tubular form.
[0023] As regards details the contractile hose 3 of the working
example possesses an elongated hose body 5 consisting of a material
with rubber elastic properties. As a material more particularly
rubber itself or another elastomeric material is employed. In the
wall of the hose body 5 a strand structure 6 is embedded, which is
for the sake of simplicity only indicated in chained lines, which
is completely surrounded by the material of the hose body 5 and is
coaxial to the body.
[0024] Preferably the structural design of the contractile hose 4
is the same as that described in the said patent publication WO
00/61952 A1. In the following explanations about the strand
structure 6 there is accordingly a limitation the principal
features. As regards further details attention is called to the
content of the above mentioned specification.
[0025] The strand structure 6 comprises strands 7a and 7b arranged
to cross over one another and having a high tensile strength. These
strands are collected in two strand groups including on the one
hand the strands 7a and on the other hand the strands 7b, the
strands 7a and 7b extending within a respective strand group having
the same longitudinal orientation. The two strand groups themselves
are arranged in a crossed over configuration as is illustrated in
FIG. 1 in the enlarged part thereof, showing the strand structure
looking radially in relation to longitudinal axis 9 of the
actuating means 1.
[0026] Preferably there is no physical contact between the two
strand groups. The material of the hose body 5 holds the strand
groups constantly at a radial distance apart in relation to each
other. Direct contact between the strand groups 7a and 7b, which
would cause increased friction may thus be excluded.
[0027] The contractile hose 4 has its two axial end sections 10--in
the drawing only illustrated in connection with the sectioned left
hand head piece 2--so secured to the respectively associated head
piece 2 and 3 that on the one hand there is a fluid-tight
connection between the hose body 5 and the respective head piece 2
and 3 and on the other hand tension forces are able to be
transmitted to the respective head piece 2 and 3.
[0028] In its interior the contractile hose delimits an interior
space 13 which at the end is terminated at the ends by the two head
pieces 2 and 3. Into the interior space 13 there opens at least one
fluid duct 14, which in the working example extends through the
first head piece 2 outside the plane of the drawing. The outer end
of the fluid duct 14 is so designed that a fluid line, not
illustrated in detail, is able to be attached with which the
connection with a pressure source may be produced. By the use of an
intermediately placed control valve arrangement, not illustrated in
detail, there is accordingly the possibility of supplying fluid
pressure medium, for example compressed air, through the fluid duct
14 for the purpose of activating the actuating means, into the
interior of the hose, or for the purpose of deactivating the
actuating means by letting off fluid from the interior space 13 of
the hose.
[0029] Preferably the actuating means 1 is operated with a gaseous
medium and more particularly compressed air. It is however suitable
for operation with a hydraulic fluid, for instance oil or water
too.
[0030] Each head piece 2 and 3 is provided at an externally
accessible point with force output connection means 17. In the
working embodiment same are constituted by a threaded sections.
They render possible the attachment of the respective head piece 2
and 3 to a component, not illustrated. For instance it would be
possible to secure the first head piece 2 at its force output means
17 stationarily on a holding structure and to the connect the other
head piece 3 with a machine part moving in relation to the holding
structure. The output means 17 are as a rule connected with such
components, which in the case of need must be drawn together with a
certain force.
[0031] The operating pressure building up in the interior space 13
of the hose during activation of the actuating means causes an
actuation of the contractile hose 4 such that there is a radial
expansion. The consequence of this is that the contractile hose 4
simultaneously undergoes an axial contraction, the axial tension
forces then resulting acting to produce a mutual movement together
of the head pieces 2 and 3. It is in this manner that components
secured to the two head pieces 2 and 3 may be shifted in relation
to each other.
[0032] The drop in pressure taking place on deactivation in the
interior space 13 in the hose means that the contractile hose 4
returns to the original condition of extent. In case of need this
return movement may however be aided with additional means, as for
example spring means.
[0033] The particular movement and deformation characteristics of
the contractile hose 4 result from the above mentioned integrated
strand structure 6. Owing to the crossed over configuration, which
in the working example results from an opposite helical course of
the two strand groups in relation to the longitudinal axis 9, there
are rhombic grid areas. Owing to the internal pressure actuation of
the contractile hose 4 a change of the angles of the rhombs is
caused, something which ultimately causes the effects
described.
[0034] In order to transmit the tension forces to the head pieces 2
and 3 the contractile hose 4 has its end sections 10 firmly clamped
in an annular clamping gap or nip 18 in the respectively associated
head piece 2 and 3.
[0035] The clamping gap 18 is located radially between the outer
periphery of an inner head piece part 22 and the outer head piece
part 23 coaxially surrounding the outer head piece part 23. In this
case the clamping gap 18 is provided with an axially orientated
annular clamping gap opening 24 facing the respectively other head
piece 2 and 3 and through which the contractile hose 4 extends into
the clamping gap 18.
[0036] The inner head piece part 22 is preferably that respective
component of the head piece 2 and 3, which is provided with the
force output means 17. Its first attachment section 25, which in
the example is stud-like, 25 extends from the end some distance
into the contractile hose 4, the outer periphery of such attachment
section 25 being provided with a first saw tooth serrated area 27.
At the same axial level as the first attachment section 25 the
inner head piece part 22 is surrounded, with the hose end section
10 is axially in between, by a sleeve-like attachment section 26 of
the outer head piece part 23, whose inner periphery is provided
with a second saw tooth serrated area 28.
[0037] The individual teeth 32 and 33 of the saw tooth serrated
areas 27 and 28 are annularly shaped and with a form concentric to
the longitudinal axis 9, the teeth being arranged in sequence in
the direction of the longitudinal axis 9, that is to say axially,
this resulting in a saw tooth serrated form in the axial
direction.
[0038] As more particularly clearly depicted in FIG. 2 the saw
tooth serrated areas 27 and 28 are so designed that their flat
tooth flanks 34 face the clamping gap opening 24 and accordingly
the respectively opposite other head piece. On the other hand the
steep tooth flanks 35 face forward toward the front end, opposite
to the contractile hose 4, of the respective head piece 2 and
3.
[0039] FIG. 2 furthermore clearly shows that the two saw tooth
serrated areas 27 and 28 are so arranged that their teeth are
respectively arranged in pairs at the same level so that in the
axial direction, that is to say in the direction of the
longitudinal axis 9 there is a plurality of pairs of teeth, one
respective tooth 32 of the first saw tooth serrated area 27 and a
tooth 33 of the second saw tooth serrated area 28 being radially
opposite each other. Several such radial "tooth planes" are
indicated in chained lines in FIG. 2.
[0040] The outer head piece part 23 constitutes a compression
sleeve 37 and is radially pressed with radial deformation together
with the hose end section 10 surrounded by it, the hose end section
10 being supported in a radially inward direction by the first
attachment section 25 gripping it of the inner head piece part 22.
Owing to such pressed connection the teeth 32 and 33 are forced
into the wall of the hose body 5, while the hose material then
displaced is received in the intermediate spaces 38 between teeth.
It is in this manner that the entire clamping gap 18 with the saw
tooth serrations is filled up with the material of the hose body 5.
In conjunction with the strong pressing effect the resulting
interlocking and hooking hold lead to a firm engagement with the
hose end section 10 and prevent its dropping out even under
extremely high tension forces.
[0041] The compression sleeve 17 bears against the inner head piece
part 22 axially to resist the acting tension forces. For this
purpose the inner head piece part 22 possesses an axially
projecting first abutment face 42 in the working example, which is
orientated axially to the fore, that is to say away from the
contractile hose 4. This first abutment face 42 preferably has an
annular form and is located on a radially projecting annular collar
44 (delimiting the clamping gap 18 on the front side opposite to
the clamping gap opening) on the inner head piece part 22. The
annular collar 44 thus extends radially past the first saw tooth
serrated area 27.
[0042] A second abutment face 43 provided on the compression sleeve
37 and preferably also annular, faces the first abutment face 42
and is axially opposite to it. It is located on an annular
projection 45 axially to the fore of the second attachment section
26, such projection 45 extending inward and hooking about the
annular collar 44 at the the front axial side opposite to the
clamping gap 18.
[0043] The two abutment faces 42 and 43 serve not only for the
transmission of force but also for positioning the compression
sleeve 37 during assembly.
[0044] Prior to assembly the compression sleeve 37 is so radially
expanded in accordance with FIG. 3 that the radial distance between
the first and second envelope faces of the two saw tooth serrated
areas, defined by the tips of the teeth 32 and 33, of the two saw
tooth serrated areas 27 and 28 is the same as the wall thickness of
the contractile hose 4 or is slightly larger. The inner diameter of
the annular projection 45 is at the same time somewhat smaller than
the outer diameter of the annular collar 44 so that there is a
radial overlap. In this condition, after the hose end section 10 to
be secured has been slipped over the first saw tooth serrated area
27 of the inner head piece part 22, the compression sleeve 37 is
indicated by the arrow slipped from the front side coaxially onto
the inner head piece part 22 until the annular projection 45
engages the annular collar 44 and accordingly the desired axial
slipping-on position of the compression sleeve 37 is reached, the
teeth 32 and 33 lying in pairs at the same axial level.
[0045] After this using a pressing tool, not illustrated in detail,
a deforming force radially orientated in relation to the
longitudinal axis 9 is exerted on the compression sleeve 37 as
indicated by the arrows 53 so that the there is
[0046] a radial deformation of the compression sleeve 37 in
connection with a reduction in diameter of the second envelope face
47 and of the annular projection 45. In this case the contractile
hose 4 is firmly radially pressed between the two saw tooth
serrated areas 27 and 28.
[0047] In order to ensure that the contractile hose 4 can be
reliably shifted into the desired slip on position during assembly
the annular collar 44 also functions as an abutment for slipping on
the contractile hose. The contractile hose 4 is slipped on so far
from the rear side onto the inner head piece part 22 that its end
face 54 engages the annular collar 44.
[0048] In order to ensure during the following compression that
material of the hose body 5, which is prevented from axially
deforming, is able to move out of the way and is not crushed by
excessive compression, there is an outwardly extending result gap
55 adjoining the front end of the clamping gap 18, hose body
material displaced during compression being able to flow off
through such gap.
[0049] In the working embodiment the annular gap 55 extends into
that portion which is located radially between the annular collar
44 and the section, which surrounds it, of the compression sleeve
37. On pressing the compression sleeve 37 the radial height of the
annular gap 55 is reduced as can be readily seen from a comparison
of the FIGS. 3 and 2.
[0050] Circumferential grooves 53 extending in the outer periphery
of the compression sleeve 37 facilitate holding in the pressing
tool, not illustrated.
[0051] In the working embodiment the first abutment face 42
constitutes the flank of an annular groove termed a locating groove
57, which is axially to the fore of the annular collar 44 and whose
second flank is located on a further annular collar 58, which is
located at a distance in front of the annular collar 44. The outer
diameter of the further annular collar 58 is smaller than that of
the annular collar 44 serving for setting the slipping on position
and is slightly smaller than the inner diameter of the undeformed
annular projection 45. Accordingly the annular projection 45 can,
during assembly by slipping on, slide over the further annular
collar 58. During the following radial pressing it moves into the
locating groove 57 so that the compression sleeve 37 is also
reliably prevented from moving forward in relation to the inner
head piece part 22.
[0052] As has been found a particularly satisfactory interlocking
effect is obtained if the two saw tooth serrated areas 27 and 28
widen conically toward the axial clamping gap opening 24, through
which the contractile hose 4 extends. In other words the two
envelope faces 46 and 47 have a conical shape tapering toward the
front side of the respective head piece 2 and 3. The apex angle is
however relatively small and preferably is of the order of
approximately 4 degrees. This results in an oblique slope between a
respective envelope face 46 and 47 and the longitudinal axis 9 of
approximately 2 degrees.
[0053] The envelope lines, defined by the two envelope faces 46 and
47, of the two saw tooth serrated areas 27 and 28 are preferably
parallel to each other. Furthermore the individual teeth 32 and 33
are preferably identically designed. Accordingly there is a
constant surface pressure along the entire clamping zone covered by
the saw tooth serrated areas 27 and 28.
[0054] It has been found to be advantageous to have one tooth per
millimeter length of a respective saw tooth serrated area 27 and
28. It has furthermore turned out to be advantageous to design the
teeth so as to have a height equal to one quarter of the wall
thickness of the hose body 5 to be secured. In the case of typical
applications the contractile hose 4 in the deactivated home
position has an outer diameter of 10, 20 or 40 mm, a number of
teeth equal to 12, 18 and, respectively, 29 being satisfactory and
convenient. The height of the teeth is more particularly the same
in all these design sizes.
[0055] In the mounted state the contractile hose 4 preferably has a
somewhat larger diameter than in the non-mounted state. This is
more particularly because of the conically tapering form of
clamping gap in the slip-on direction of the contractile hose 4.
The contractile hose 4 is in this case caused to slightly bulge
outward in the clamping gap opening 24 and in the rear end section
62, directly following same in the axial direction, of the clamping
gap 18.
[0056] Along the above mentioned rear end section 62 the clamping
gap is preferably unserrated and has a smooth surface. Accordingly
the load on the contractile hose 4 in the transition zone merging
with the clamping gap 18 is minimized.
[0057] Finally it is also an advantage if the radial distance apart
between the two envelope faces 46 and 47 of the two saw tooth
serrated areas 27 and 28 in the completely assembled state of the
compression sleeve 37 is at least equal to the radial dimensions of
the strand structure 6 embedded in the wall of the hose body and
preferably is slightly larger than it. Such a configuration is
depicted in FIG. 2. Accordingly it is possible to ensure that the
strand structure is not damaged by the teeth 32 and 33 pressed into
the hose body 5.
[0058] As further shown in FIG. 2 the strand structure 6 maintains
an at least essentially linear form along the length of the
contractile hose 4 even in the completely assembled state of the
respective head piece 2 and 3. If the saw tooth serrated areas 27
and 28 were axially offset in relation to each other, one
respective tooth of the one saw tooth serrated area on the
contractile hose could be pressed into the radially opposite tooth
gap so that there might be a corrugated deformation of the strand
structure 6 and resulting longitudinal stretch zones, which could
impair strength. Owing to the particular tooth arrangement this
disadvantage is countered.
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