WO2023284987A1

WO2023284987A1 - Column-shaped objects reversing device

Info

Publication number: WO2023284987A1
Application number: PCT/EP2021/070038
Authority: WO
Inventors: Joy Andreas ZIMMERMANN
Original assignee: Nobag, Nobs Engineering Ag
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-19

Abstract

A device (1) for reversing columnar objects (3), preferably of circular cross-section, comprises a helical passage (17) for reversing the columnar-shaped object (3). In an arrangement for handling such objects, the device (1) is preferably oriented such, that the linear movements of the objects entering and leaving the device (1) and the screw axis of the helical passage (17) of the device (1) are oriented each at about 45° with respect to gravity in order that the objects propagate swiftly in the device (1).

Description

Column-shaped Objects Reversing Device

The present invention relates to a device for reversing column-shaped objects according to the preamble of claim 1 and a method of reversing such objects.

In many areas of manufacturing and product handling, column shaped objects need to be transported with their orientation well-defined. One kind of such objects are rounds for guns or ordnance. In a certain stage of the manufacturing process, the empty shells are longitudinally moved through channels or tubes after being isolated and longitudinally aligned. However, as these alignments use gravity or centrifugal forces, the shells are oriented such that the bottom is ahead. For the further process, however, it is preferred or even indispensable that the opening is ahead, so that the shells need to be reversed.

Obviously, the problem that column-shaped objects need to be reversed appears in other manufacturing or object handling processes as well. Column-shaped objects may even comprise objects deviating from ideal columns, like bottles.

Generally, such a column-shaped object features a ratio diameter to length of at least 1.2, preferably at least 1.4.

In processes where high throughput rates are required, the reversing of the bodies poses problems. A solution consists in holding each object in a device, e.g. a rotating disk. The objects enter the device in one orientation and leave it in the reversed orientation.

Another known technique uses gravity. The objects hit a support in a tilted orientation with regard to gravity force, so they tip over, i.e. rotate on the transverse axis, and fall down in reverse order. Instead of gravity, a push may be exerted on the objects. Generally, it may be said that the objects perform a kind of a somersault.

Due to the clocked operation modus the known reversing devices show a limited throughput only. The devices using a forced rotation on the transverse axis are additionally prone to jamming because the rotation is performed substantially without guidance.

Therefore, it is an object to provide a device and method for reversing a column-shaped object with improved performance, where performance comprises at least one of speed and jamming-safety. Such a device is defined in claim 1. The further claims propose preferred embodiments and a method for reversing such an object.

Accordingly, the reversing is performed in converting the longitudinal movement into a rotation around a transverse axis and back again. The rotation is controlled in that the objects move along a spiral pathway adapted to the body. The rotation is performed while the object is moving in a direction different from longitudinal, preferable transversally thereto. The conversion from longitudinal propagation to spiral propagation is preferably effected by an inclined surface in the passage ahead of a stop. Laterally arranged of the inclined surface is the entrance of the spiral passage.

Surprisingly, this manner of reversibly creating a rotating movement occurs smoothly and swiftly in comparison with known devices. The invention will be further described by way of preferred exemplary embodiments with respect to the Figures:

Fig. 1 Illustration of the operation principle of a reversing device

Fig. 2 Top view on a device

Fig. 3 Inclined 3-dimensional side-view of the device

Fig. 4 Section according to IV-IV in Fig. 2

Fig. 5 Section according to V-V in Fig. 2, yet entry and exit exchanged

Fig. 6 Enlarged partial view of entry and exit according to VI in Fig. 4

Fig. 7,8 Schematic sectional views of a columnar object in the helical passage

Fig. 9 Section of a body having constant thickness

Fig. 10 Section of a distorted columnar object

Fig. 11 Section of a 2^nd distorted columnar object

Fig. 1 illustrates the construction and function of the reversing device 1 in a schematical manner. The device is tilted at an angle of about 45° (with respect to gravity), so that the column-shaped objects 3, e.g. shells, enter the device 1 at entry 5 and leave it at its exit 7 with gravity 9 as the driving force, and at an angle of 45°.

In the entry section 11 of the device, the linear movement 13 is converted in a rotational movement 18 around a transverse axis of the objects 3 in combination with a 2^nd linear movement at angle of 90 “with respect to initial linear movement by an inclined and bent surface 15 at the end of the entry section 11. This transition to a different movement occurs simultaneously with entering in the helical or spiral passage 17. The screw axis 19 of the helix corresponds to the direction of the 2^nd linear movement. While the bodies 3 pass the helical passage 17, they are turned by 180°, i.e. reversed. At the exit 21 of the helical passage 17, the movement of the objects 3 is once again converted in a linear movement 23 by a further inclined and bent surface 25. The objects 3 leave the device 1 in direction parallel to the entering direction.

This exemplary model shows characteristics which in combination are deemed essential for the real world device, even if it is supposed that not all these features need to be implemented:

• The spiral passage features a 180° turn. Theoretically there may additionally be any number of full turns (360°), yet practically, additional full turns do not appear to be advantageous.

The exactly reversed position at exit has the advantage that exit and entry linear movements are parallel.

• The functional parts of the device are substantially point symmetric. Accordingly, the device may be used reversed, i.e. entry and exit exchanged.

• The linear movements on entry, in the helical passage and on exit are all directed downward by an angle of 45°.

Figs. 2 to Fig. 5 show a real embodiment of the device 1. The objects move along a tubular channel 29. It is attached to the entry 5 of the device 1 by a clamp 31. Another clamp 33 attaches the exit tube 35 to the device 1. The transparent presentation of Fig. 2 additionally shows the interior functional parts discussed above, namely entry section 11 , inclined and bent surface 15 at entry, helical passage 17, inclined and bent surface 25 at exit, and the exit section 22.

The sections of Figs. 4 and 5 show even better the design of the interior of the device, in particular the helical passage 17.

Additionally visible is the funnel section 27 at the entry 5 and the exit 7. As the transport conduits (tubes) 29 will generally have a cross-section slightly different from the passages in the device, the entry 5 and the exit 7 are provided each with a tapered circumference 39. If the device is used for shells, tapering 39 is narrowing toward the exit, e.g. the cross-section is continuously diminished by 1% or 0.5% or less: As the bottom of a shell has a rounded or chamfered circumference and the shells arrive bottom first at the entry 5, this circumference compensates a minimal threshold at the entry. Flowever, on leaving the device, the open top of the shell is ahead which is generally sharp and straight. Hence, a slightly tapering exit has proven to be advantageous to safeguard an unproblematic and quick exiting of the shell.

In the example, both entry 5 and exit 7 are provided with such a tapering 39 each so that the device may be used in both directions.

The cross-section of the helical passage 17 is closely fitted to the dimensions of the object 3 to be reversed. The free space 46 around the object orthogonally to its longitudinal axis, i.e. the proportion between height 47 of the cross-section and diameter of the object, is at most 1.1 , or even at most 1.05, at most 1.03, or at most 1.01. The same applies to the proportion between length of object 3 and width 49 of the cross- section of passage 17, yet a more elevated proportion may be allowed, as guidance in longitudinal direction is not of the same importance for an unproblematic passage of the object. The ratio between width 49 and height 47 is at least 1.5 and preferably at least 2.

The edges 41 of the helical passage 17 are beveled 51 , so that, in particular in combination with a close fit of passage 17 with the dimension of the object 3, there will occur an only punctual, well-defined contact 53 between circumference of top or bottom rim of an object 3 with one or more bevels 51. These minimal contacts will cause less resistance to the propagation of the object and though guide it through the passage.

The bevels 51 may be straight (shown), yet curved (convex or concave) shapes are conceivable. The bevels may comprise at most the peripheral 10 % of the diameter, 0 % to maximally 10 % and minimally 90 % to 100 % of a diameter of the object. Other conceivable limits are peripherally at most 5 %, 2 %, 1 %.

In practice, the device allowed a throughput of up to 60 objects per minute, i.e. up to 60 per minutes without build-up of a queue before ahead of the device or increased danger of jamming. However, throughput may be increased well up to the double, in particular up to about 125 objects per minute.

Even if experience hints that about regular circular-cylindrical columnar objects 3 are best suited to be reversed by the device, it is conceivable that other shapes may be handled as well:

• The diameter of the objects may vary. It is supposed that barbell shapes behave like columns of constant diameter as the largest diameters are located at the ends of the objects and guide the body in the cavity of the helical passage 17. Yet, the section of the cavity may be adapted to the actual shape of the objects 3. It is conceivable that at least at two circumferences, preferably the largest circumference, the width of the passage 17 fits with the diameter of the object 3 in order to attain a save guidance within the helical passage and to avoid jamming. For example, a bottle-shaped object 54 may be considered (cf. Fig. 8).

• Other cross-sections than circular of the objects 3 are conceivable. In particular, a body of equal thickness 55 is conceivable (cf. Fig. 9). Due to its angularly constant diameter, it behaves like a roller (cylindrical cylinder) if not attached to a shaft. Even "distorted" cylindrical shapes may be considered. As a more regular example thereof, an elliptical cross-section 61 and a partial elliptical cross-section 63 may be considered.

The passage 17 is adapted to the minimal diameter of the cross-section, where "minimal cross-section" may even be comprised as a locally minimal diameter. As is evident for the body of Fig. 10, the thickness orthogonally to the locally smallest diameter 67, corresponding to the short half-axis 69 of the elliptical cross-section of Fig. 9, is smaller than the diameter 67. Obviously, the entry section 11 needs to be designed that the objects 5 are rotationally oriented such that they enter the helical passage 17 with the (locally) minimal diameter in the plane of the cross-section of the helical passage as shown in Fig. 7. It is, however, foreseeable that such bodies, as they cannot perform free turns around their longitudinal axis, are prone to jamming, e.g. in case of debris in the helical passage 17.

• Depending on the actual shape of the objects 3, the bevels 51 may not be present or even replaced be depressions or recesses in order to attain a smooth and jamming- free movement of the reversed objects in the helical passage. In particular irregularly shaped (uneven, scraggy) terminal borders may render a recess instead of a bevel 51 advantageous.

The body of the device 1 , in particular the interior surfaces in contact with the object 3, are made of a material or at least lined with a material of low friction with the surface of the object 3 in question, and need to be smooth.

Feasible materials are metals or polymeric materials for example PTFE (polytetrafluoroethylene) or a polyamide. The body of the device, in particular the helical passage and the entry and exit section 11 , 22 with the guiding inclined and bent surfaces 15, 25, may be produced preferably by an additive manufacturing process, yet it is deemed possible to use subtractive processes as well. The body of the device may substantially consist of two halves which are point- symmetrically shaped at least regarding the interior surfaces in contact with the column shaped bodies to be reversed. The two halves may be attached to each other at a surface corresponding to section plane IV-IV. This bipartite design even allows easy access to the interior space by detaching one body half from the other. The halves may be attached to each other by screws.

According to the exemplary embodiment, the spiral passage (or pathway) is designed that the object rotates about around its center, or more generally about around it center of moment of inertia. The latter requires an adaptation to the mass distribution of the object to be reversed. Hence the cross-section of the spiral passage is aligned with respect to the central axis of the spiral movement of the object while being reversed, i.e. the center axis of the helical pathway is aligned with a precision of at most 20 % of a dimension of the cross-section, better at most 15 %, 10 %, or at most 5 %, to the gravity center of the cross-section of the helical passage, or alternatively to the center of momentum of inertia of the presumed objects to be reversed the passage is designed for. Thereby, forces transversal to the rotational axis of the reversing movement are reduced, so that the guiding parts of the spiral passage are less subject to wear and tear and the reversing performs swiftly.

From the description of a preferred embodiment including variations, the one skilled in the art may still derive further variants and modification without leaving the scope protection of the invention which is defined by the claims. Conceivable is in particular one or more of the following:

• At least the helical passage is lined with a dry lubricant, e.g. graphite or talcum.

• At least the helical passage is provided with a supply of a liquid lubricant.

• A fluid stream, preferably an air stream, is generated in the helical passage (17) in order to push the column-shaped objects through. The fluid (air) may be injected, about at the entry of the helical passage or sucked off about at its exit, or both.

• The column-shaped objects may be provided with a kind of lubricant to swiftly pass through the longitudinal conveyers.

• The parts of the device, or at least one of them, are held by magnets to the other part or parts for facilitated maintenance.

Claims

1. Device (1 ) for reversing a column-shaped object (3, 54), the column-shaped object extending along a longitudinal axis and the device comprising a passage for the column-shaped object, characterized in that the following sections are present in the device to be subsequently passed by the column-shaped object:

• an entry section (11 ), in which the column-shaped object is movable generally in direction of the longitudinal axis;

• a reversing section comprising a helical passage (17) of substantially helical shape wound along a helical line around a screw axis, wherein a cross-section of the helical passage orthogonal to the helical line has a width extending radially from the screw axis of the helical passage and a height orthogonally thereto, so that the column-shaped object is linearly movable through the helical passage in a first direction orthogonally to its longitudinal axis in performing a rotation around the screw axis;

• an exit section (22), in which the column-shaped object is movable generally in direction of the longitudinal axis.

2. The device (1) according to claim 1 , characterized in that at least one of bottom and top circumferential edges of the helical passage (17) are beveled (51), rounded, shaped as recesses, or a mixture thereof in adaptation to the objects to be reversed.

3. The device (1) according to one of claims 1 to 2, characterized in that the passage is lined with a material of low friction, preferably a dry lubricant or a polymer material, more preferably one of PTFE (polytetrafluoroethylene), polyamide, fiber- reinforced PTFE, fiber-reinforced polyamide.

4. The device (1) according to one of claims 1 to 3, characterized in that the helical passage (17) comprises a turn of 170° to 190°, preferably 175° to 185°, even more preferably of 178° to 182°, and most preferably of about 180°, optionally complemented with at least one full turn (360°).

5. The device (1) according to one of claims 1 to 4, characterized in that the quotient width (49):height (47) of the helical passage (17) is at least 1.5, preferably at least 2.

6. The device (1) according to one of claims 1 to 5, characterized in that the cross- section of the helical passage (17) is radially aligned to the screw axis of the helical passage (17) in a way, that the alignment is either with regard to the geometric mass center or with regard to the center of moment of inertia of a column-shaped object present in the helical passage, so that translational forces transversal to the screw axis on the column-shaped objects by the rotation are reduced, the alignment being at most 20 % of a dimension transversal to the screw axis, preferably at most 15 %, 10 %, or at most 5 % thereof with increasing preference.

7. The device (1) according to one of claims 1 to 6, characterized in that a relative pitch of the helical passage, measured as the quotient [(height of the screw axis for a full turn (360°)) / (height of cross-section of passage)], is at least 5, more preferably at least 6 and even more preferably at least 8.

8. The device (1) according to one of claims 1 to 7, characterized in that the device, preferably the arrangement of interior surfaces of entry section (11), reversing section, and exit section (22) designed to guide a column-shaped object, is substantially point symmetric.

9. The device (1) according to one of claims 1 to 8, characterized in that at least the entry section (11) comprises toward its bottom and substantially diametrically opposed to the helical passage (17) an inclined surface (15, 25) arranged to impose a rotational momentum on a column-shaped body moving into the entry section.

10. The device (1) according to one of claims 1 to 9, characterized in that the helical passage (17) has at least one of the following properties, preferably both: A) substantially cylindrical helix; B) substantially constant pitch.

11. The device (1 ) according to one of claims 1 to 10, characterized in that the screw axis penetrates the helical passage (17) at between 25% and 75% of its radial extension, preferably at 33% to 67% of its radial extension, more preferably at 40% to 60% of its radial extension, and most preferably about centrally (50 of the radial extension).

12. The device (1) according to one of claims 1 to 11 , characterized in that the longitudinal axis of at least one of entry section (11) and exit section (22), preferably both, are arranged in an angle of 80° to 100°, preferably 85° to 95°, more preferably 88° to 92°, and most preferably about 90°, relative to the screw axis of the helical passage (17).

13. Arrangement for handling column-shaped objects (3) comprising the device (1) according to one of claims 1 to 12, characterized in that the screw axis of the helical passage (17) is arranged at an angle of 30°to 60°, preferably 40°to 50°, and most preferably about 45°, relative to gravity in order that the column-shaped objects move swiftly through the passage (17).

14. Method of reversing a column-shaped object (3) having a longitudinal axis orthogonal to its cross-section, characterized in that the column-shaped objects (3) are moved in the direction of the longitudinal axis over a surface (15, 25) inclined with respect to the longitudinal axis, so that movement along the longitudinal direction is converted in a rotation movement, and are pushed into a helical passage (17), and that on exit of the helical passage, the column-shaped objects hit on another inclined surface (15, 25) arranged to convert the rotation into a linear movement along the longitudinal axis.