US20120103376A1

US20120103376A1 - Free-Standing Umbrella Having a Cooling Apparatus

Info

Publication number: US20120103376A1
Application number: US13/320,059
Authority: US
Inventors: Klaus Becher
Original assignee: Becher Textil und Stahlbau GmbH
Current assignee: Becher Textil und Stahlbau GmbH
Priority date: 2009-05-13
Filing date: 2010-05-11
Publication date: 2012-05-03
Also published as: EP2429329A1; WO2010130729A1; DE102009021186A1

Abstract

On a free-standing umbrella, particularly a garden umbrella, patio umbrella or the like, displaying a canopy (1) supported by a central or eccentric upright tube (3), a cooling apparatus integrated in the free-standing umbrella is provided for use of the umbrella in countries with a hot climate, comprising a liquid connection (14) located in the lower area of the upright tube (3), a liquid feed line (15) extending along the upright tube (3), and at least one spray nozzle (16) that is located under the canopy (1), connected to the feed line (15), and allows liquid supplied at a defined pressure via the feed line (15) to be sprayed in small droplets, such that the droplets evaporate at a certain temperature in the area under the canopy (1). (FIG. 1)

Description

This application is the National Stage of International Application No. PCT/EP2010/056448, filed on May 11, 2010, which claims the benefit of Germany patent application 10 2009 021 186.1 (filed on May 13, 2009), both of which are hereby incorporated by reference.

I. FIELD OF THE INVENTION

The invention relates to a free-standing umbrella, particularly a sunshade, garden umbrella, patio umbrella or the like, displaying a canopy, supported by a central or eccentric upright tube, and a cooling apparatus, where the cooling apparatus comprises a liquid connection located in the lower area of the upright tube, a liquid feed line extending along the upright tube, and at least one spray nozzle that is located under the canopy and connected to the feed line, by means of which liquid supplied at a defined pressure via the feed line can be sprayed in small droplets, such that the droplets evaporate at a certain temperature in the area under the canopy.

II. BACKGROUND OF THE INVENTION

On a free-standing umbrella of this kind, the canopy can be mounted on the upright tube of the column in stationary manner, without being foldable or collapsible. On other kinds of free-standing umbrellas, the canopy can be of foldable or collapsible design, where a runner displaceable along the upright tube is customarily provided, to which supporting struts linked to canopy rods of the canopy are connected in articulated fashion.
Free-standing umbrellas, which are used in the restaurant and hotel sector, for example, usually have relatively large canopy diameters of 4 m and more, and are intended to be suitable for all weather conditions and provide protection from sun, wind and rain. It is furthermore desirable for them to make it as pleasant as possible for persons under the canopy. To this end, it is familiar practice to equip free-standing umbrellas with auxiliary facilities, such as radiators and lighting.
An umbrella of the kind mentioned in the opening paragraph is known from U.S. Pat. No. 6,886,759 B. On this umbrella, the liquid feed line leads, below the canopy, into a branched system displaying multiple branch lines that are fixed on some of the canopy rods of the canopy and each display a spray nozzle at the end. The object of the present invention is to further develop a free-standing umbrella in such a way that it can also be used particularly advantageously in countries with a hot climate, especially in subtropical, tropical and equatorial zones.

III. SUMMARY OF THE INVENTION

According to the invention, the object is solved in that a ring manifold system for the liquid is located around the upright tube below the canopy, displaying a ring-shaped duct, into which the feed line leads, and from which multiple branch lines distributed around the circumference of the ring manifold system lead, each of which is connected to a spray nozzle, where the ring manifold system displays two ring manifold consoles that rest against each other, where the ring-shaped duct is integrally molded in the form of an annular groove in the face side of at least one of the ring manifold consoles that faces towards the other ring manifold console.
According to the invention, a central distribution system for the liquid to be sprayed is provided around the upright tube of the free-standing umbrella.
The particularly advantageously designed ring manifold system according to the invention can, on relatively large umbrellas with correspondingly dimensioned upright tubes, also be located inside the upright tube. Under certain circumstances, at least part of the spray nozzles can also be located inside the upright tube.
In this way, approximately uniform spraying of the liquid by the spray nozzles is achieved on an umbrella that is essentially rotationally symmetrical about the upright tube. Needless to say, in the event of an asymmetrical umbrella design, optimum spraying of the space can be accomplished by means of a suitable arrangement and length of the branch lines.
The evaporation of the liquid sprayed or atomized under the canopy causes evaporative cooling of the ambient air. The size and distribution of the droplets in the area under the canopy can be set via the design of the spray nozzle and the selection of the pressure of the liquid to be sprayed. The evaporative cooling of the ambient air can then be regulated as a function of the air temperature. Depending on the air temperature, the size and distribution of the droplets sprayed by the at least one nozzle must be such that the droplets evaporate in the upper region of the area under the canopy, in order to avoid contact between falling droplets and the persons or objects located below the free-standing umbrella.
The cooling apparatus is preferably designed in such a way that drinking water can be used as the liquid. In particular, the at least one spray nozzle can be designed in such a way that the drinking water can be fed at a relatively low pressure between 3 and 100 bar, preferably 4 and 10 bar, and the liquid connection is thus suitable for connection to an external drinking-water line. Any insufficient pressure can be increased by means of an upstream booster pump, while any excessive pressure can be reduced by means of an intermediate pressure-reducing valve.
Any hygienic and operational obstacles (coarse particles, furring), possibly resulting from the externally supplied water used to operate the cooling apparatus being unsuitable from the medical or technical point of view, can be counteracted by upstream filter systems, such as used in clinics and hospitals, for example.
In a preferred embodiment of the invention, a central distribution system for the liquid to be sprayed is provided around the upright tube of the free-standing umbrella. To this end, a ring manifold system for the liquid can be located around the upright tube under the canopy, being connected to the feed line and displaying multiple branch lines distributed around its circumference, each of which is connected to a spray nozzle.
On relatively large umbrellas with correspondingly dimensioned upright tubes, the ring manifold system can also be located inside the upright tube. Under certain circumstances, at least part of the spray nozzles can also be located inside the upright tube.
In this way, approximately uniform spraying of the liquid by the spray nozzles is achieved on an umbrella that is essentially rotationally symmetrical about the upright tube. Needless to say, in the event of an asymmetrical umbrella design, optimum spraying of the space can be accomplished by means of a suitable arrangement and length of the branch lines.
In a preferred embodiment, the ring manifold system displays a ring-shaped duct, into which the liquid feed line leads, and from which the branch lines lead.
To this end, the ring manifold system can display two ring manifold consoles that rest against each other, where the ring-shaped duct is integrally molded in the form of an annular groove in the face side of at least one of the ring manifold consoles that faces towards the other ring manifold console.
Annular grooves for accommodating O-rings can expediently be provided on both sides of the duct to seal the ring-shaped duct between the two ring manifold consoles.
In a particularly simple embodiment, the duct for the liquid is integrally molded in the corresponding face side of one of the ring manifold consoles, the grooves for the O-rings being integrally molded in the opposite face side of the other ring manifold console.
On a foldable or collapsible free-standing umbrella displaying a runner displaceable along the upright tube, to which supporting struts linked to canopy rods of the canopy are connected in articulated fashion, provision is expediently made for the umbrella structure to be designed, and the ring manifold system to be located between runner and canopy, in such a way that closing of the umbrella into the folded or collapsed position is not impeded, meaning that no part of the cooling apparatus needs to be removed to close the umbrella. In particular, the spray nozzles can be located between the supporting struts, such that they come to rest between them when the umbrella is collapsed, as a result of which the umbrella can be closed to the same degree as an umbrella not having the ring manifold system with spray nozzles according to the invention.
On a free-standing umbrella of this kind, the runner can be connected to a retaining rod or a retaining rope for raising it into, or locking it in, its upper position, said rod or rope extending along the upright tube above the runner. The runner can be raised by pulling on the retaining rod or the retaining rope, and locked in its upper position by locking the retaining rod or the retaining rope. A retaining rope of this kind can have one end fastened to the runner, or to the upright tube above the runner, and be guided via one or more pulleys. On an umbrella of this kind, the ring manifold system is likewise located between the runner and the supporting struts in such a way that complete closing of the umbrella into the folded or collapsed position is not impeded.
In another embodiment of the free-standing umbrella, the canopy rods can be linked to a stem section that can be displaced in telescoping fashion relative to the upright tube and supports a crown, where the crown and the runner move in opposite directions when opening and closing the umbrella as a result of at least one deflecting strut that is located above the runner and connected in articulated fashion to the upright tube at one end, and connected in articulated fashion to a canopy rod at the other end. In this embodiment, the ring manifold system according to the invention is located between the supporting struts and the at least one deflecting strut in such a way that complete closing of the umbrella into the folded or collapsed position is not impaired.
In a particularly advantageous development of a free-standing umbrella of this kind, the runner can, for locking in its upper position, be fastened in releasable fashion to one end of a first retaining device, preferably displaying a retaining rod or a retaining rope, the other end of which is fastened to the crown or to the upper area of the displaceable stem section. The ring manifold system expediently displays a through hole or a lateral slit, through which the retaining rod or the retaining rope is guided in moving fashion.
In a development of an umbrella structure of this kind, especially for large umbrellas, it is advantageous to provide a second retaining device, preferably displaying a retaining rod or a retaining rope, one end of which is fastened to the upper area of the upright tube, the other end being fastened to the runner in releasable fashion. After fastening the first retaining device on the runner, this second retaining device serves to subsequently tauten the membrane of the canopy. The second retaining rod or the second retaining rope is expediently fixed in place via a tension-lever lock on the runner. Similarly, the first retaining rod or the first retaining rope can be fixed in place via a tension-lever lock on the runner.
If a second retaining rod or a second retaining rope is used, it can be guided in moving fashion through a second through hole or a second lateral slit in the ring manifold system.
In a particularly advantageous development of the invention, the liquid feed line is arranged in such a way that it runs within the column. It then expediently emerges from the upright tube below an externally located ring manifold system, and is connected to the ring-shaped duct via an externally located connection. The liquid connection is located externally on the lower area of the upright tube or below the upright tube.
On an aforementioned free-standing umbrella having a crown and a runner moving in opposite directions, and a stem section supporting the crown and extending in telescoping fashion into the upright tube from above, the upright tube and/or the stem section are profiled in such a way that they display at least one chamber between the stem section and the upright tube that extends along the upright tube and through which the liquid feed line runs.
In an advantageous embodiment of the invention, between four and sixteen spray nozzles are arranged around the upright tube, with roughly equal angles between adjacent spray nozzles. This guarantees largely uniform spraying of the liquid around the upright tube of the free-standing umbrella. In appropriate circumstances, more than sixteen spray nozzles can also be used.
The ends of the spray nozzles display atomizer nozzles that are directed in such a way towards the canopy that they form an angle of 0° to 45° relative to the horizontal. Where appropriate, however, the direction of the atomizer nozzles can also point upwards at an angle of more than 45°. In appropriate circumstances, the atomizer nozzles can also point downwards.
Particularly preferably, the direction of the axis of the spray mist should not be oriented in a direction below the periphery of the canopy, such that the cooling action due to adiabatic evaporation is essentially effective within the space delimited by the canopy and a horizontal surface delimited by the periphery of the canopy. Expressed in positive terms, the spraying direction of the spray nozzles should be directed at the outer edge of the canopy or above it. Therefore, the spraying angle must be selected in accordance with the height of the spray nozzle arrangement relative to the outer edge of the umbrella.
It is moreover preferred that the reach of the spray mist is set such that wetting of the canopy is largely avoided.
Open to consideration as the spray nozzles are nozzles through which the water is expelled at high pressure, breaking it down into small droplets. Alternatively, other spraying systems not requiring high pressure can be used, e.g. electrostatic spraying systems. The spray reach of the spraying system should be at least two-third of the umbrella radius, or of the distance between the umbrella axis and the outer edge of the canopy.
Depending on ambient temperature and atmospheric humidity, the quantity of spraying agent sprayed through the entirety of the spray nozzles can be between 1 and 5 liters per square meter of the area covered by the canopy and hour.
In accordance with the invention, success is achieved in creating a climate under the umbrella that displays a temperature up to 10° C. lower than the surroundings, without the clothing of persons under the umbrella becoming damp. The atomizer nozzles can be designed in such a way that the liquid sprayed by them preferably forms a conical or fan-shaped cloud. Under certain circumstances, the cloud can also display a different geometry, depending on the design of the atomizer nozzles.

IV. BRIEF DESCRIPTION OF THE DRAWINGS

A preferred practical example of the invention is described in more detail below on the basis of the drawing.

The drawing shows the following:

FIG. 1 A side view of an umbrella in opened position,

FIG. 2 Details of the umbrella shown in FIG. 1 on a larger scale, and

FIG. 3 A cross-sectional view along Line III-III in FIG. 2.

V. DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 essentially shows a complete view of the practical example of a freestanding umbrella considered. On this umbrella, the canopy 1, of which only the canopy rods 2 are shown, is supported by a central upright tube 3.
This is a collapsible free-standing umbrella displaying a runner 4 that can be displaced along upright tube 3 and to which supporting struts 5, linked to canopy rods 2 of canopy 1, are connected in articulated fashion.
As can likewise be seen from FIG. 1, the crown 6 of the umbrella, connected to canopy rods 2 in articulated fashion, is supported by a stem section 7, which is guided in telescoping fashion in upright tube 3. By means of deflecting struts 8, one end of each of which is connected in articulated fashion to upright tube 3 and the other end of each of which is connected in articulated fashion to a canopy rod 2, crown 6 and runner 4 move in opposite directions to each other when the umbrella is opened and closed.
To lock runner 4 in its upper position, a first retaining rod 9, extending parallel to upright tube 3, is provided, the upper end of which is fixed on crown 6, and the lower end of which can be fastened on runner 4 in releasable fashion via a first tension-lever lock 10.
For subsequent tautening of the membrane (not shown in the drawing) of canopy 1, a second retaining rod 11 is provided, one end of which is fastened in the upper area of upright tube 3, and the other end of which can be fastened on runner 4 in releasable fashion via a second tension-lever lock 12.
Upright tube 3, designed as a metal tube, is inserted in a mounting sleeve 13, likewise designed as a metal tube, the lower area of which (not shown in the drawing) is connected to an umbrella base or secured in the ground.
Integrated in the free-standing umbrella shown in FIG. 1 is a cooling apparatus displaying a liquid connection 14, located in the lower area of upright tube 3, a liquid feed line 15 extending along upright tube 3, and a ring manifold system 17 connected to multiple spray nozzles 16.
In addition to the cooling apparatus, the free-standing umbrella shown in FIG. 1 is provided with a suitable lighting device 18. It can also be equipped with other auxiliary facilities, such as heating and sound transmission systems.
The cooling apparatus can be seen in more detail in FIG. 2.
FIG. 2 shows an interrupted section of the area of upright tube 3, on or in which the cooling apparatus is located.
Liquid connection 14, located outside upright tube 3 in its lower area, is fastened to mounting sleeve 13 for upright tube 3 by means of a torque bracket 19. It is connected to an external drinking-water line 21 via a coupling device 20, designed as a rapid-action coupling. Provided upstream of coupling device 20 is a mechanically or electromechanically actuated shut-off/control valve 22, by means of which the supply of drinking water can be shut off and/or controlled.
Liquid connection 14 is connected to liquid feed line 15, leading to ring manifold system 17, via an adapter 23 and an elbow fitting 24, preferably of the cutting-ring type.
As shown in the upper area of FIG. 2, liquid feed line 15, which extends within upright tube 3 and is preferably made of stainless steel, leads into ring manifold system 17, which consists of two ring manifold consoles 25 and 26 that rest against each other and are fastened to each other by pressure-fit connections 27.
Ring manifold consoles 25 and 26, which are fastened together, are fixed in place on the upright tube by screws 28.
A ring-shaped duct 29 is integrally molded in the face side of upper ring manifold console 25 that lies opposite lower ring manifold console 26. To seal ring-shaped duct 29 between the two ring manifold consoles 25 and 26, the face side of lower ring manifold console 26 that lies opposite upper ring manifold console 25 displays annular grooves 30 on both sides of duct 29 for accommodating preferably closed O-rings.
As can further be seen from FIG. 2, liquid feed line 15 emerges from upright tube 3 through an opening 31 below ring manifold system 17, and is connected via an elbow fitting 32, preferably a swiveling or rotating fitting of the cutting-ring type, to ring-shaped duct 29. To this end, the face side of lower ring manifold console 26 lying opposite upper ring manifold console 25 displays, between annular grooves 30, an outlet opening for the supplied liquid that lies opposite ring-shaped duct 29.
As can be seen in more detail from the top view of ring manifold system 17 in FIG. 3, eight spray nozzles 16, distributed around upright tube 3 at equal angular intervals, are connected to ring manifold system 17. Spray nozzles 16 are each connected by an elbow fitting 33 to ring-shaped duct 29 in upper ring manifold console 25.
At the end of a nozzle feed line 34, spray nozzles 16 display an atomizer nozzle 35 that, like nozzle feed line 34, is preferably made of stainless steel.
Nozzle feed line 34, with atomizer nozzle 35 located on its end, points upwards towards the canopy at an angle of roughly 30° relative to the horizontal.
As can be seen from FIG. 3, upright tube 3 is designed as a profiled metal tube with struts 36 pointing towards the inside. Formed between struts 36 are chambers 37, which can serve to accommodate lines guided along the inside of upright tube 3.
Liquid feed line 15 runs through chamber 37 shown on the right in FIG. 3.
Stem section 7 (not shown in FIG. 3) is connected to crown 6 and partly extends within upright tube 3, having an outside diameter determined by the diagonal spacing of struts 36. Chambers 37 are therefore located between upright tube 3 and stem section 7 guided in telescoping fashion therein, such that the lines, particularly liquid feed line 15, can be laid between upright tube 3 and stem section 7 without obstruction.
As can likewise be seen from FIG. 3, through openings 38, running in the longitudinal direction of upright tube 3, are provided in the two ring manifold consoles 25 and 26, through which first retaining rod 9 and second retaining rod 11 (cf. FIG. 1) are guided in sliding fashion relative to ring manifold system 17.
As shown in FIG. 3, the outer contour of the two ring manifold consoles 25 and 26 of ring manifold system 17 is of such a shape that its radial extension about upright tube 3 is kept as small as possible, taking into consideration the design-related arrangement of the connection of liquid feed line 15 to ring-shaped duct 29, spray nozzles 16 and through openings 38. As a result, ring manifold system 17, and spray nozzles 16 connected to it, do not impede folding of the umbrella into its completely closed position.
Spray nozzles 16 are arranged around ring manifold system 17 and upright tube 3 in such a way that they are located between the supporting struts in the circumferential direction, meaning that they come to rest between them when the umbrella is folded up. As a result, ring manifold system 17 need not be removed from upright tube 3 in order to close the umbrella completely.

VI. LIST OF REFERENCE NUMBERS

1 Canopy
2 Canopy rod
3 Upright tube
4 Runner
5 Supporting strut
6 Crown
7 Stem section
8 Deflecting strut
9 First retaining rod
10 First tension-lever lock
11 Second retaining rod
12 Second tension-lever lock
13 Mounting sleeve
14 Liquid connection
15 Liquid feed line
16 Spray nozzle
17 Ring manifold system
18 Lighting device
19 Torque bracket
20 Coupling device
21 Drinking-water line
22 Control valve
23 Adapter
24 Elbow fitting
25 Ring manifold console
26 Ring manifold console
27 Press-fit connection
28 Screw
29 Duct
30 Groove
31 Opening
32 Elbow fitting
33 Elbow fitting
34 Nozzle feed line
35 Atomizer nozzle
36 Strut
37 Chamber
38 Through opening

Claims

1. Free-standing umbrella having

a canopy supported by at least one of a central or eccentric upright tube, and

a cooling apparatus, where the cooling apparatus comprises

a liquid connection located in a lower area of the upright tube,

a liquid feed line extending along the upright tube,

at least one spray nozzle that is located under the canopy and connected to the feed line, by means of which liquid supplied at a defined pressure via the feed line can be sprayed in small droplets, such that the droplets evaporate at a certain temperature in the area under the canopy,

a ring manifold system for the liquid is located around the upright tube below the canopy, the ring manifold system having a ring-shaped duct, into which the feed line leads, and from which multiple branch lines distributed around the circumference of the ring manifold system lead, each of which is connected to a spray nozzle, where the ring manifold system includes two ring manifold consoles that rest against each other, where the ring-shaped duct is integrally molded in the form of an annular groove in the face side of the ring manifold consoles that faces towards the other ring manifold console.

2. Free-standing umbrella according to claim 1, wherein drinking water can be used as the liquid, and the liquid connection is designed for connection to a drinking-water line.

3. Free-standing umbrella according to claim 1, wherein annular grooves for accommodating O-rings are provided on both sides of the ring-shaped duct.

4. Free-standing umbrella according to claim 3, wherein the ring-shaped duct is integrally molded in the face side of one of the ring manifold consoles, and the annular grooves are integrally molded in the opposite face side of the other ring manifold console.

5. Free-standing umbrella according to claim 4, wherein said free-standing umbrella is designed as a foldable or collapsible umbrella that includes a runner displaceable along the upright tube, to which supporting struts linked to canopy rods of the canopy are connected in articulated fashion, and that is designed in such a way that the ring manifold system is located between runner and canopy without impeding closing of the umbrella into the folded or collapsed position.

6. Free-standing umbrella according to claim 5, wherein the runner is connected to at least one of a retaining rod and a retaining rope for at least one of raising it and locking it in its upper position, at least one of said rod and said rope extending along the upright tube above the runner, and the ring manifold system is located between the runner and the supporting struts in such a way that complete closing of the umbrella into the folded or collapsed position is not impeded.

7. Free-standing umbrella according to claim 5, wherein the canopy rods are linked to a stem section that can be displaced in telescoping fashion relative to the upright tube and supports a crown, where the crown and the runner move in opposite directions when opening and closing the umbrella as a result of at least one deflecting strut that is located above the runner and connected in articulated fashion to the upright tube at one end, and connected in articulated fashion to a canopy rod at the other end, and

the ring manifold system is located between the supporting struts and the at least one deflecting strut in such a way that complete closing of the umbrella into the folded or collapsed position is not impaired.

8. Free-standing umbrella according to claim 7, wherein for locking said umbrella in an upper position, the runner can be fastened in releasable fashion to one end of at least one of a retaining rod and a retaining rope, the other end of which is fastened to at least one of the crown and to the upper area of the displaceable stem section, and

the ring manifold system includes at least one of a through hole and a lateral slit, through which at least one of the retaining rod and the retaining rope is guided in moving fashion.

9. Free-standing umbrella according to claim 8, wherein the liquid feed line extends within the upright tube.

10. Free-standing umbrella according to claim 9, wherein between four and sixteen spray nozzles are arranged around the upright tube with roughly equal angles between adjacent spray nozzles.

11. Free-standing umbrella according to claim 10, wherein the spray nozzles display an atomizer nozzle at the end of a nozzle feed line.

12. Free-standing umbrella according to claim 11, wherein the atomizer nozzle is directed in such a way towards the canopy that the direction in which the liquid is sprayed or atomized forms an angle between 0° and 45° relative to the horizontal.

13. Free-standing umbrella according to claim 1, wherein said freestanding umbrella is designed as a collapsible umbrella that includes a runner displaceable along the upright tube to which supporting struts linked to canopy rods of the canopy are connected in articulated fashion, and that is designed in such a way that the ring manifold system is located between runner and canopy without impeding closing of the umbrella into the collapsed position.

14. Free-standing umbrella according to claim 13, wherein the canopy rods are linked to a stem section that can be displaced in telescoping fashion relative to the upright tube and supports a crown, where the crown and the runner move in opposite directions when opening and closing the umbrella as a result of at least one deflecting strut that is located above the runner and connected in articulated fashion to the upright tube at one end, and connected in articulated fashion to a canopy rod at the other end, and

15. Free-standing umbrella according to claim 14, wherein for locking said umbrella in an upper position, the runner can be fastened in releasable fashion to one end of at least one of a retaining rod and a retaining rope, the other end of which is fastened to at least one of the crown and to the upper area of the displaceable stem section, and

the ring manifold system includes at least one of an opening through which at least one of the retaining rod and the retaining rope is guided in moving fashion.

16. Free-standing umbrella according to claim 1, wherein the liquid feed line extends within the upright tube.

17. Free-standing umbrella according to claim 1, wherein between four and sixteen spray nozzles are arranged around the upright tube with roughly equal angles between adjacent spray nozzles.

18. Free-standing umbrella according to claim 1, wherein the spray nozzles display an atomizer nozzle at the end of a nozzle feed line.

19. Free-standing umbrella according to claim 18, wherein the atomizer nozzle is directed in such a way towards the canopy that the direction in which the liquid is dispensed forms an angle between 0° and 45° relative to the horizontal.