U.S. patent application number 10/048269 was filed with the patent office on 2002-08-08 for fluid-actuated cylinder and method for manufacturing it.
Invention is credited to Colombo, Antonio.
Application Number | 20020104433 10/048269 |
Document ID | / |
Family ID | 11445408 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020104433 |
Kind Code |
A1 |
Colombo, Antonio |
August 8, 2002 |
Fluid-actuated cylinder and method for manufacturing it
Abstract
A fluid-actuated cylinder and a method for manufacturing it,
including a head and a connecting tube to be coupled; coupling is
obtained by compression of the two members along their axis,
deforming the end of the tube by using, as a die for the
deformation of the tube, a particular ring which is fitted on the
head member and is coaxial thereto.
Inventors: |
Colombo, Antonio; (Legnano,
IT) |
Correspondence
Address: |
Coleman Sudol Sapone
714 Colorado Avenue
Bridgeport
CT
06605-1601
US
|
Family ID: |
11445408 |
Appl. No.: |
10/048269 |
Filed: |
January 28, 2002 |
PCT Filed: |
June 22, 2001 |
PCT NO: |
PCT/EP01/07107 |
Current U.S.
Class: |
92/169.1 |
Current CPC
Class: |
B21K 25/00 20130101;
F15B 15/1438 20130101; B23K 2101/06 20180801; B23K 20/02 20130101;
B21D 39/06 20130101 |
Class at
Publication: |
92/169.1 |
International
Class: |
F01B 011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2000 |
IT |
MI2000A001511 |
Claims
1. A fluid-actuated cylinder comprising at least one head which is
applied hermetically to the end of a tube which is folded inside an
annular groove formed in said head, characterized in that it
comprises a deformation ring which is arranged between said head
and said folded end of said tube.
2. The cylinder according to claim 1, characterized in that said
deformation ring is fitted on said head at a tapering portion of
the surface of the head.
3. The cylinder according to claim 1 or 2, characterized in that
said deformation ring comprises a convex chamfered internal surface
which has its own radius of curvature.
4. The cylinder according to one or more of the preceding claims,
characterized in that said tapering portion comprises a radius of
curvature which corresponds to the radius of curvature of said
internal surface of said deformation ring.
5. A method for manufacturing a fluid-actuated cylinder comprising
at least one head and a tube to be coupled, characterized in that
it comprises the steps of: forming a groove in an outer cylindrical
surface of said head proximate to the coupling region, applying a
ring which comprises a chamfered internal surface, at a tapering
portion, having a similar radiusing, which is formed on said outer
surface of said head; performing an axial compression between said
head and said tube, making the end of said tube slide inside said
groove, so that said end of said tube is deformed and compressed
against said tapering portion of said head member, forcing said
ring to maintain a forced arrangement between said head member and
said connecting tube by elastic reaction.
6. A device for the hermetic assembly of at least one head and a
tube which are adapted to constitute a fluid-actuated cylinder,
characterized in that it comprises a deformation ring which can be
applied to said head at a tapering portion of said head in order to
form a groove in which the end of said tube is deformed by axial
compression of said tube and said head.
Description
[0001] The present invention relates to a fluid-actuated cylinder
and to a method for manufacturing it.
[0002] The mutual assembly of a head and a tube of pneumatic
cylinders is a critical operation, because once the seal has been
provided between the tube and head at the different operating
pressures, the assembly must ensure resistance to the thrust
applied by the operating pressure to the cross-section of the head,
resistance to the axial mechanical stresses applied by the mass
connected to the stem-piston assembly, and resistance to the
torsional stresses that occur during the fixing of the
cylinder.
[0003] Various methods are known which allow head-tube coupling
according to the characteristics that the head-tube assembly is to
have in order to withstand the operating stresses.
[0004] EP-A-0351317, U.S. Pat. No. 4,073,219, FR-A-2544806 disclose
methods for assemblying cylinders.
[0005] One method in particular, and specifically the cylinder with
rolled tube method, provides a product whose mechanical
characteristics determine a field of use which includes the
products manufactured with the method according to the present
invention.
[0006] In the cylinder with rolled tube method, the head-tube
coupling is provided by way of the deformation of the tube, which
is obtained by rolling and subsequent upsetting the edge of the
heads onto the tube. The seal is provided by means of an O-ring or
by a mechanical compression seal.
[0007] In particular, this fastening method has the drawback of
requiring an expensive assembly apparatus, including a customized
numeric-control lathe, and suitable tools for rolling the different
diameters.
[0008] Another drawback relates to the particularly long times for
tooling and programming the machine for rolling the different
diameters and for the rolling and upsetting operations.
[0009] Another drawback is that the method is hardly flexible and
requires large investments in machines in order to meet market
requirements.
[0010] The aim of the present invention is to provide a method for
the assembly of fluid-actuated cylinders and the like which
overcomes the drawbacks of the cited prior art.
[0011] Another object of the invention is to provide an assembled
product which is reliable in use and has competitive costs.
[0012] This aim, this object and others, which will become better
apparent hereinafter, are achieved by a fluid-actuated cylinder and
the like comprising at least one head which is applied hermetically
to the end of a tube which is folded inside an annular groove
formed in the head, characterized in that it comprises a
deformation ring which is arranged between the head and the folded
end of the tube.
[0013] This aim, this object and others, which will become better
apparent hereinafter, are also achieved by a method for
manufacturing fluid-actuated cylinders comprising at least one head
and a tube to be coupled, characterized in that it includes the
steps of:
[0014] forming a groove in an outer cylindrical surface of the head
proximate to the coupling region, applying a ring comprising a
chamfered internal surface, at a tapering portion, which has a
similar radiusing, formed on the outer surface of the head;
[0015] performing an axial compression between the head and the
tube, sliding the end of the tube inside the groove, so that the
end of the tube is deformed and compressed against the tapering
portion of the head member, forcing the ring to maintain a forced
arrangement between the head member and the connecting tube with
elastic reaction.
[0016] Further characteristics and advantages of the present
invention will become better apparent from the description of
preferred but not exclusive embodiments thereof, illustrated only
by way of non-limitative example in the accompanying drawings,
wherein:
[0017] FIG. 1 is a partially sectional side elevation view of a
head applied to a cylinder, illustrating an initial step of
assembly according to the invention;
[0018] FIG. 2 is an enlarged-scale view of FIG. 1, showing in
detail the surface of the tube that enters the groove;
[0019] FIG. 3 is a side elevation view, similar to FIG. 1, of an
intermediate step of assembly, according to the invention;
[0020] FIG. 4 is an enlarged-scale view of FIG. 3, showing in
detail the surface of the tube that is deformed;
[0021] FIG. 5 is a view, similar to FIGS. 1 and 3, of a final step
of assembly according to the invention;
[0022] FIG. 6 is an enlarged-scale view of FIG. 5, showing in
detail the surface of the tube, forced between the head and the
ring.
[0023] With reference to the above figures, a fluid-actuated
cylinder according to the invention, designated by the reference
numeral 100, has a head 3, which is applied hermetically to the end
of a tube 6, and a ring 1 with a particular internal radiusing
which constitutes a chamfered surface 2 which has a radius of its
own.
[0024] The ring 1 is fitted on a tang 13 which is monolithic with
the head 3 at a tapering portion 4 which is formed on the outer
surface of the tang. The particular configuration of the chamfered
surface 2 of the ring 1 and of the tapering portion 4, which
follows the profile of the internal chamfered surface 2, forms a
groove 5 around the cylindrical surface of the tang 13. The groove
is used as a die for guiding the deformation of an end 16 of the
tube 6 to be coupled to the head 3, so that by being trapped
between the head 3 and the ring 1 the assembly of the members is
ensured.
[0025] In particular, as shown in FIGS. 1 and 2, by axial
compression, represented schematically by the arrow F, between the
head 3 and the tube 6, the end 16 of the tube 6 is made to slide
inside the groove 5. The internal chamfer 2 of the ring 1, together
with the tapering portion 4 which has a similar radius of
curvature, guides the end 16 of the tube 6 in its deformation until
contact occurs with the head 3 on a bottom 7 of the groove 5, as
shown in FIG. 4. During deformation, the ring 1 transfers the
compression force to the tube 6, but when the end 16 of the tube 6
rests against the head 3 it is the tube itself that discharges the
compression force onto the ring 1, which compresses the folded part
of the tube 6 against the tapering portion 4 of the head 3, as
shown in FIG. 6.
[0026] Such final step ensures tightness at the operating pressures
and forces the ring 1 to maintain a forced arrangement between the
elastic reaction of the tube 6 against the head 3 and the head
itself.
[0027] A condition is thus produced by way of which the only way to
remove the head is to widen the ring or cut the tube.
[0028] Advantageously, a system for centering the ring 1 on the
head 3 is provided.
[0029] The fastening method according to the invention has the
advantage that it can use a simple press in order to assemble heads
and tubes of various diameters by simply changing the centerings,
with low costs in terms of investments in machines and with great
flexibility.
[0030] The assembly of the front and rear heads occurs by means of
a single operation, in shorter times, making the system more
competitive from the economic point of view.
[0031] The interference produced between the tube and the head
further ensures tightness without gaskets and very high resistance
to axial thrusts and torsion.
[0032] In practice it has been observed that the invention achieves
the intended aim and objects.
[0033] The cylinder and the method according to the invention are
susceptible of numerous modifications and variations, all of which
are within the scope of the inventive concept; all the details may
furthermore be replaced with technically equivalent elements.
[0034] The materials used, as well as the dimensions, may of course
be any according to requirements and to the state of the art.
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