BE1025381B1 - Improved method for making a compressed air cylinder and the resulting compressed air cylinder - Google Patents

Abstract

The present invention relates to a method for making a compressed air cylinder, an accessory, and the resulting compressed air cylinder. An accessory comprising at least two protrusions and an auxiliary opening is provided. A profile comprising a cylindrical inner wall is provided. The cylindrical inner wall comprises a longitudinal direction and a housing diameter perpendicular to the longitudinal direction. The profile further comprises at least two elongated recesses essentially parallel to the longitudinal direction. The attachment is placed on the profile, the at least two protrusions of the attachment being introduced longitudinally into the at least two elongated recesses of the profile. A piston is inserted through the auxiliary opening until the piston is surrounded by the cylindrical inner wall of the profile.

Description

IMPROVED METHOD FOR MAKING A COMPRESSED AIR CYLINDER AND THE OBTAINED COMPRESSED AIR CYLINDER

TECHNICAL DOMAIN N

The invention relates to a method for making a compressed air cylinder, and the resulting compressed air cylinder.

STAND OF THE TECHNICAL

US 4 932 313 describes a compressed air cylinder.

The above-mentioned compressed air cylinder comprises a cover and a bottom fixed with an elongated connecting element transverse to the longitudinal direction of the cylinder. This causes considerable stresses on the cylinder. Furthermore, the compressed air cylinder comprises a one-piece piston mounted on the piston rod via screw thread. Such a mounted piston is susceptible to passage of air. Furthermore, such a mounted piston can come loose. Furthermore, it is difficult to insert the piston rod with piston into the cylinder tube without damaging the opening.

It is an object of the present invention to find a solution to at least some of the aforementioned problems.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to a method for making a compressed air cylinder, according to claim 1.

In a second aspect, the present invention relates to an attachment for inserting a piston into a profile, according to claim 15.

In a third aspect, the present invention relates to a compressed air cylinder, according to claim 16.

The present invention is advantageous because with the aid of an accessory the piston can be introduced into the cylinder without damaging the opening.

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DESCRIPTION OF THE FL GUREN

Figure 1 shows a schematic representation of an embodiment of a piston rod according to the present invention.

Figures 2 and 3 show schematic representations of an embodiment of a method according to the present invention, comprising mounting an embodiment of a piston on a piston rod according to Figure 1.

Figure 4 shows a schematic representation of an embodiment of a method according to the present invention, comprising mounting an embodiment of a lid according to the present invention to an embodiment of a profile according to the present invention, and introducing a piston according to figures 2 and 3 in the profile using an embodiment of an attachment according to the present invention.

Figure 5 shows a schematic representation of an embodiment of a method according to the present invention, comprising mounting an embodiment of a nose according to the present invention to the profile of Figure 4.

Figure 6 shows a schematic representation of an embodiment of a compressed air cylinder according to Figure 5, wherein the cover and the nose each comprise a connection point.

Detailed description

The invention relates to a method for making a compressed air cylinder, an attachment for introducing a piston into a profile, and a compressed air cylinder. The invention is summarized in the section provided for this purpose. In the following, the invention is described in detail, preferred embodiments are explained, and the invention is illustrated with reference to examples.

Unless defined otherwise, all terms used in the description of the invention, including technical and scientific terms, have the meaning as generally understood by those skilled in the art of the invention. For a better assessment of the description of the invention, the following terms are explicitly explained.

BE2017 / 5979 "One", "de" and "it" in this document refer to both the singular and the plural unless the context clearly presupposes otherwise. For example, "a segment means one or more than one segment.

When "around or" around in this document is used with a measurable quantity, a parameter, a duration or moment, and the like, variations are meant of +/- 20% or less, preferably +/- 10% or less, more preferably +/- 5% or less, even more preferably +/- 1% or less, and even more preferably +/- 0.1% or less than and of the quoted value, insofar as such variations apply in the described invention. However, this should be understood to mean that the value of the quantity in which the term "about" or "round" is used is itself specifically disclosed.

The terms "include," "include," "consist of," "include," "include," "include," "include," "include," and are inclusive or open terms indicating the presence of what follows, and which do not exclude or prevent the presence of other components, features, elements, members, or steps.

The citation of numerical intervals by the end points includes all integers, fractions and / or real numbers between the end points, including these end points.

In a first aspect, the present invention relates to a method for making a compressed air cylinder. The compressed air cylinder can be single-acting or double-acting. The compressed air cylinder is preferably double-acting. A profile is provided. The profile comprises a cylindrical inner wall. The cylindrical inner wall comprises a longitudinal direction and a housing diameter essentially perpendicular to the longitudinal direction. The profile further comprises at least two, preferably at least three, most preferably at least four elongated recesses essentially parallel to the longitudinal direction. The profile preferably comprises an essentially uniform cross-section perpendicular to the longitudinal direction. The profile preferably consists of aluminum. The profile is preferably extruded. Furthermore, a piston and a piston rod are provided, the piston being mounted on the piston rod. The piston rod preferably consists of stainless steel or hard chromium-plated steel. The piston comprises a piston diameter essentially the same as the housing diameter. Preferably the piston comprises an alloy comprising zinc, aluminum, magnesium and copper (such as, for example, Zamak). An accessory is also provided. The attachment comprises at least two

BE2017 / 5979 protrusions and an auxiliary opening. The auxiliary opening preferably comprises a cylindrical part and a funnel-shaped part. The cylindrical portion preferably comprises an auxiliary diameter substantially the same as the housing diameter. The funnel-shaped portion preferably comprises a minimum diameter equal to the auxiliary diameter. The accessory preferably comprises extruded aluminum. The method comprises placing the attachment on the profile; inserting the piston through the auxiliary opening of the attachment, such that the piston is surrounded by the cylindrical inner wall of the profile; and removing the attachment from the profile. Placing the attachment on the profile includes inserting the at least two protrusions of the attachment along the longitudinal direction into the at least two elongated recesses of the profile.

In a second aspect, the present invention relates to an attachment for inserting a piston into a profile. The accessory comprises at least two protrusions and an auxiliary opening. The auxiliary opening comprises a cylindrical portion and a funnel-shaped portion. The cylindrical portion comprises an auxiliary diameter. The funnel-shaped portion comprises a minimum diameter equal to the auxiliary diameter. The cylindrical portion and the funnel-shaped portion preferably comprise a common feed-through direction for feeding the piston through the auxiliary opening. The protrusions preferably protrude according to said feed-through direction.

In a third aspect, the present invention relates to a compressed air cylinder obtained via a method according to the first aspect of the present invention.

A person of ordinary skill in the art will appreciate that the three aspects of the present invention include a common inventive concept. Features described for one of the aspects may therefore also apply to the other aspects. That is why in the following no distinction is made anymore between the various aspects. The following description, preferred embodiments, and examples may therefore apply to any of the aspects.

The present invention is advantageous because with the aid of an accessory the piston can be introduced into the profile without damaging the opening.

In a preferred embodiment, the attachment is manufactured by sawing off a piece of profile with a saw blade; and turning an interior chisel

BE2017 / 5979 bevel on the inner wall of the sawn-off piece of profile at at least 30 ° and at most 60 °, preferably at least 45 °, with the feed-through direction of the fitting, which corresponds to the longitudinal direction of the sawn-off piece of profile. Furthermore, at least two bolts are tapped and filed into the elongated recesses of the sawn-off section of profile. The internal bevel forms the funnel-shaped part of the auxiliary opening.

In a preferred embodiment, a cover, a nose, and at least four self-tapping bolts are provided. The cover is mounted at a first end of the profile by placing the cover against the first end and inserting at least two of the self-tapping bolts into the elongated recesses of the profile. After the cover is mounted at the first end, the attachment is placed at the second end of the profile. The second end is in this case spaced from the first end in the longitudinal direction by the profile. After the piston has been inserted and the attachment removed, the nose is mounted at the second end of the profile by placing the nose against the second end and inserting at least two of the self-tapping bolts into the elongated recesses of the profile. The cover is preferably provided with holes for the passage of self-tapping bolts. The nose is preferably provided with holes for the passage of self-tapping bolts. The cover preferably consists of an alloy comprising zinc, aluminum, magnesium and copper, such as, for example, Zamak. The nose preferably consists of an alloy comprising zinc, aluminum, magnesium and copper, such as, for example, Zamak. The self-tapping bolts are preferably made of galvanized steel.

This is advantageous for various reasons. First, the same recesses are used for inserting the protrusions of the attachment when placing the attachment on the second end as for mounting the nose on the second end using the at least two self-tapping bolts. A second advantage relates to the direction of introduction of the self-tapping bolts, which is in the longitudinal direction (since the elongated recesses are essentially parallel to the longitudinal direction). The mounted bolts do not cause any tension on the cylindrical wall. Consequently, there is no risk of deformation and leaks on the piston as a result.

In a preferred embodiment, the piston rod comprises a threaded rod portion, a support portion which is thicker than the threaded rod portion, and a threaded rod portion which is positioned

BE2017 / 5979 between the threaded rod section and the spherical section. The piston comprises a first non-threaded piston part, a sealing ring, a magnet holder, and a second piston part with a thread. The method comprises the steps of placing the first piston member over the rod portion without screw thread and against the support portion; paving the sealing ring over the rod and against the first piston egg; and pivoting the magnet holder and the second piston member with screw thread phot against the first piston member. The magnet holder is herein positioned between the first and the second piston egg. Preferably, glue is applied to the threaded rod portion, preferably by substantially uniformly blowing glue over the threaded rod portion before the magnet holder and the second piston member. Preferably, each of the first piston member, the second piston member and the magnet holder comprises a diameter substantially equal to the piston diameter. Preferably the second piston egg is further fixed on the piston rod by means of an Allen key. Preferably the first and the second piston egg consist of an alloy comprising zinc, aluminum, magnesium and copper, such as, for example, Zamak. The sealing ring preferably consists of high-quality fluorine-containing rubber (such as, for example, FPM) or nitrile butadiene rubber (NBR). Preferably, the magnet holder comprises polytetrafluoroethylene (such as, for example, Teflon).

This is advantageous because the multi-part piston, comprising the sealing ring positioned between the magnet holder and the first piston egg, and is preferably arranged at least partially with glue for air impermeability. Moreover, the glue and / or the fixing of the second piston egg prevent the mounted piston from coming loose. A further advantage is the determination of the position of the piston within the profile on the basis of magnets in the magnet holder.

In a preferred embodiment, the profile is deburred at both ends (first and second end) and both on the inside and the outside over a distance of at least 0.5 mm and at most 5 mm, preferably at least 1 mm and at most 3 mm _f under a angle with the longitudinal direction of at least 35 ° and at most 55 °, preferably at least 40 ° and at most 50 °. Deburring the profile is advantageous to ensure air tightness after mounting the lid and / or nose.

In a preferred embodiment, the profile is sawn perpendicular to the longitudinal direction; cleaned with a blow gun and a degreaser; and then deburred as described above.

BE2017 / 5979

In a preferred embodiment the piston rod is sawn, after which it is turned in a lathe. A key face on a front side of the piston rod is then milled; and the key face is further flattened with a file.

In a preferred embodiment, the lid and the nose each comprise a connection point for air supply and / or discharge. Plugs are inserted into the connection points of the lid and nose. Preferably the plugs comprise polyvinyl chloride (PVC).

In a preferred embodiment, the compressed air cylinder is tested for leaks over the piston.

In a preferred embodiment, the compressed air cylinder is tested for leaks on the nose.

In a preferred embodiment, the profile is greased with a silicone-based grease, for mounting the lid and for inserting the piston.

In a preferred embodiment, the piston is greased with a silicone-based grease for insertion of the piston into the profile.

In the following, the invention is described a.d.h.v. a non-limiting example illustrating the invention, which is not intended or may be interpreted to limit the scope of the invention.

EXAMPLE

The example refers to figures 1 to 6.

Profile

The aluminum profile is cut in a first step. For this, a multiple length is determined for each diameter, which length is added to the stroke length. Table 1 includes examples of multiple lengths per cylinder diameter.

Table 1 - Multiple lengths per cylinder diameter

Cylinder diameter (mm) Mooring length (mm) 32 40 40 44

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50 45 63 48 80 55 100 58 125 74 160 80 200 80

The sawing machine is set after determining the length to be cut. The zero point is set first. The spacer is then shifted until the set value to be cut is reached. The spacer is clamped and the profile to be cut is placed against the spacer and clamped. After speed setting, the sawing machine is automatically moved upwards and the desired profile is sawn off. After the sawing operation, the profile, both inside and outside, is deburred by approximately 2 mm at an angle of approximately 45 °. Finally, the profile is cleaned with a blow gun and a degreaser.

Piston rod

Figure 1 shows a schematic representation of an embodiment of a piston rod (1) according to the present invention. The piston rod comprises a threaded rod portion (2), a threaded rod portion (3), a support portion (4), a key face (5), and a threaded end (6). The piston rod comprises a length L. The rod portions comprise a diameter F and a common length P. The threaded rod portion comprises a length R. The support portion comprises a diameter A. The key face comprises a diameter D. The end comprises a diameter B and a length H. The key face and the end have a common length K. Here, the lengths are determined along the axis of the piston rod. Table 2 contains examples of dimensions of piston rods.

Table 2 - Dimensions of piston rods (see Figure 1) in millimeters.

Cii. diam. a D B H K. F R P ! .. 32 12 11.2 M10 x 1.5 22 28 M8 x 1.25 18 32 118 40 16 14.5 M12 x 1.25 24 30 M10 x 1.5 18 34.5 131 50 20 19 M1 6x1.5 32 39 M14 x 1.5 18 37.5 148 63 20 19 M16 x 1.5 32 39 M16 x 1.5 24.5 49.5 162

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80 25 24 M20 X 1.5 40 50 M18 X 2.5 27 48 185 100 25 24 M20 X 1.5 40 50 M20 X 2.5 30 57 199 125 32 30 M27 X 2 54 70 M20 X 2.5 34 57 240 160 40 38.5 M36 X 2 72 91 M2 4 X 2 32 59 286 200 40 38.5 M3 6 X 2 72 91 M24 X 2 32 59 301

When machining the piston rod, the piston shaft length is determined according to the formula: L = stroke length + multiple length + special dimensions. After determining the total piston shaft length, the sawing machine is set. Zero 5 is first set. The spacer is then shifted until the set value to be cut is reached and the spacer is clamped. The piston rod to be cut is placed against the spacer and clamped. The sawing machine is started and the piston rod is professionally sawn by hand. The piston rod is then manually turned in the lathe provided for this purpose. A spanner face is milled with diameter D at the front of the piston shaft. Finally, the key face is flattened with a file.

Piston

To assemble the cylinder, the piston is first mounted on the piston rod. Figures 2 and 3 show schematic representations of mounting an embodiment of a piston on the piston rod (1). The first piston part (11) is slid over the rod part without thread (3) and against the support part (4). A sealing ring (12) is slid over the piston rod and against the first piston part (11). A special glue is applied to the threads of the threaded rod section (2) and the glue is blown evenly over the threads. It is checked whether the magnets present in the magnet holder (13) attract or repel each other. The second piston part (14), which comprises screw thread (15), and the magnet holder (13) are then rotated on the piston rod. Afterwards, the second piston part (14) is fixed by means of an Allen key. The glue is finally dried for approximately 30 minutes.

Assembly of the compressed air cylinder

After mounting the piston on the piston rod, the mounting of the cylinder cover on the aluminum cylinder profile follows. Figure 4 shows a schematic representation of mounting an embodiment of a lid (22) to an embodiment of

BE2017 / 5979 a profile (21), and inserting the piston according to figures 2 and 3 into the profile with the aid of an embodiment of an attachment (24) according to the present invention. The profile (21) was sawn off, deburred, and cleaned as described above. The profile comprises a substantially uniform cross section perpendicular to the longitudinal direction, i.e. according to the plane Q in Figure 4. Figure 4 also shows the cross section according to the plane Q. The cross section preferably comprises as a symmetry group p4 mm. The profile (21) comprises a cylindrical inner wall for forming the compressed air cylinder, as well as four longitudinal recesses for the introduction of self-tapping bolts (23, 23 ") and the recesses of the attachment (24).

The profile (21) is greased with a silicone-based grease. The cover (22) is placed against the profile (21). The cover (22) is fixed by means of four self-tapping bolts (23, 23 ").

After mounting the cylinder cover, the piston with piston rod is guided into the greased profile. This is done by placing an attachment (24) according to the present invention against the profile (21). The accessory comprises an auxiliary opening for passing a piston rod with piston (20) through the auxiliary opening according to a feed-through direction. Furthermore, the attachment comprises four protrusions protruding in the direction of transit. The auxiliary opening comprises a cylindrical portion and a funnel-shaped portion, as described in the detailed description. The piston is greased with silicone grease and introduced into the profile (21) by means of the attachment (24). The accessory (24) is subsequently removed.

The nose is then mounted on the profile (Figure 5). To this end, the nose (26) is carefully slid over the piston rod. The nose (26) is placed against the profile and mounted by means of four self-tapping bolts (23 ", 23" ").

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To test

First the cylinder is tested over the piston gaskets. To this end, compressed air is placed on a valve, so that the cylinder piston rod retracts. Upon detecting a leak over the piston gaskets, air escapes from a first to a second chamber and air bubbles arise in a reservoir. The valve is then switched over so that the piston rod makes an outgoing movement. Upon detecting a leak over the piston packings, air escapes from the second chamber to the first chamber and air bubbles arise in a second reservoir.

The cylinder is then tested for leaks at the nose. With the same pneumatic arrangement, the piston rod is made to make an input movement so that pressure is created in the first chamber. A mixture of soap and water is then sprayed onto the nose. When a nose leak is detected, visible air bubbles escape between the piston rod and the nose gasket.

Finish off

The cylinder is marked with a sticker on the profile tube. Afterwards the cylinder is provided with a nut (28) on the piston rod (see figure 6). The bolts for controlling the cylinder buffer are turned open so that a full stroke length is obtained and the profile tube is cleaned. Finally, the connection points on the lid and the nose are provided with PVC plugs, with which connections (29 ", 29") can be made in the connection points.

Claims (16)

CONCLUSI ES A method for making a compressed air cylinder, comprising the steps of: - providing a profile comprising a cylindrical inner wall comprising a longitudinal direction and a housing diameter perpendicular to the longitudinal direction, the profile further comprising at least two elongated recesses essentially parallel to the longitudinal direction; - providing a piston and a piston rod, the piston mounted on the piston rod, the piston comprising a piston diameter essentially equal to the housing diameter; - providing an attachment comprising at least two protrusions and an auxiliary opening; - placing the attachment on the profile, wherein the at least two protrusions of the attachment are inserted in the longitudinal direction into the at least two elongated recesses of the profile; - inserting the piston through the auxiliary opening until the piston is surrounded by the cylindrical inner wall of the profile; and - removing the attachment from the profile. A method according to any one of the preceding claims, wherein the auxiliary opening comprises a cylindrical portion and a funnel-shaped portion, the cylindrical portion comprising an auxiliary diameter substantially equal to the housing diameter, the funnel-shaped portion comprising a minimum diameter essentially equal to the housing diameter. Method according to any one of the preceding claims, wherein the profile comprises a substantially uniform cross-section perpendicular to the longitudinal direction. A method according to any one of the preceding claims, comprising the steps of: - providing a cover, a nose and at least four self-tapping bolts; - mounting the cover on a first end of the profile by inserting at least two of the self-tapping bolts into the elongated recesses of the profile; - after the cover has been mounted on the first end, placing the attachment on a second end of the profile; and BE2017 / 5979 - after the attachment has been removed from the profile, mounting the nose at the second end of the profile by inserting at least two of the self-tapping bolts into the elongated recesses of the profile. A method according to any one of the preceding claims, wherein the piston rod comprises a threaded rod portion, a support section thicker than the threaded rod section, and a threaded rod section positioned between the threaded rod section and the support section, the piston having a first piston section without thread, comprises a sealing ring, a magnet holder, and a second piston part with thread, the method comprising the steps of: - placing the first piston part over the rod part without a thread and against the support part; - placing the sealing ring over the rod and against the first piston part; and - rotating the magnet holder and the second piston part over the threaded rod portion against the first piston part, the magnet holder being positioned between the first and the second piston part. Method according to the preceding claim 5, comprising the step of applying glue to the threaded rod portion, preferably substantially uniformly blowing glue over the threaded rod portion. A method according to any one of the preceding claims 5 and 6, wherein each of the first piston part, the second piston part and the magnet holder comprises a diameter substantially equal to the piston diameter. A method according to any one of the preceding claims 5 to 7, wherein the second piston part is fixed by means of an Allen key. A method according to any one of the preceding claims, wherein the profile is deburred at both ends and both on the inside and the outside over a distance of at least 0.5 and at most 5 mm, preferably at least 1 and at most 3 mm, at an angle with the BE2017 / 5979 longitudinal direction of at least 35 and at most 55 °, preferably at least 40 and at most 50 °. A method according to any one of the preceding claims, wherein the profile consists of aluminum. A method according to any one of the preceding claims, comprising the steps of: - sawing the profile perpendicular to the longitudinal direction; and - cleaning the sawn profile with a blow gun and a degreaser. A method according to any one of the preceding claims, comprising the steps of: - cutting the piston rod; - turning the piston rod in a lathe; milling a key face on a front side of the piston rod; - and flattening the key plane with a file. A method according to any one of the preceding claims, wherein the lid and the nose each comprise a connection point, the method comprising the step of inserting plugs into the connection points of the lid and the nose, preferably the plugs comprising polyvinyl chloride. A method according to any one of the preceding claims, comprising the steps of: - testing the compressed air cylinder for leaks over the piston; and - testing the compressed air cylinder for leaks on the nose. An attachment for inserting a piston into a profile, the attachment comprising at least two protrusions and an auxiliary opening, the auxiliary opening comprising a cylindrical portion and a funnel-shaped portion, the cylindrical portion comprising an auxiliary diameter, the funnel-shaped portion comprising a minimum diameter equal to the auxiliary diameter. A compressed air cylinder obtained by a method according to any one of the preceding claims 1 to 14.