To cover large spaces, manufacturers produce multi-dome umbrellas. Most often with 2-4, less often with 6 domes, on one central support. Their total area varies from 8 to 100 square meters. m. Moreover, the racks themselves with weighting plates occupy only about 1-2 square meters. m. Such properties make them popular among summer cafes and restaurants.
Here we delve into the technical features of the design and elements of garden and patio umbrellas. The article will be useful to both the buyer and seller of patio umbrellas.
By design, Commercial Patio Umbrellas come with central and lateral (cantilever) supports. The latter, curved in the form of the letter “G”, is favorably distinguished by the fact that the stand is extended beyond the contour of the dome, leaving the space under it almost completely free. They easily rotate 360 ° around the base, providing stable shading of the desired location.
They are distinguished by a massive non-folding stand and a relatively complex dome opening system. Most cantilever umbrellas (with lateral support) have the ability to control the tilt of the dome, lifting it up by 20-60 °. Some factories produce elite models with the ability to raise the dome by 90 ° or turn it left and right by 90 °, achieving an absolutely vertical position of the dome in any plane.
All this, in general, determines their higher cost.
Umbrella opening mechanisms
The opening of the dome is controlled in several ways. Small models open like rain umbrellas with their hands. Another option is the rope tackle, that is, the roller system: one roller is mounted on the top of the umbrella, the other on the movable hub, where the bases of the supporting spokes converge.
Both blocks are interconnected by a rope, which, sequentially bending around all the rollers, goes down through the branch blocks. Using quality parts, the system allows you to open even the largest domes but is most often used on umbrellas up to 20 square meters. m. In the open position, the domes are fixed with a latch or a metal pin inserted into the support under the hub. Some models can have up to 4 fixed positions.
The lever system is even more convenient and, naturally, more expensive: by rotating the small handle with light movements, you can quickly open the giant domes. On elite umbrellas, it is possible to install push-button and even automated control of opening and closing, programming for a certain time, setting wind parameters, upon reaching which the umbrellas themselves will close.
Umbrellas single-dome and multi-dome
The frameworks of multi-dome umbrellas are equipped with an easily controlled swivel mechanism (360 °). Some manufacturers produce umbrellas with a flexible “arm” system – a two-piece horizontal bar. It freely rotates around the support, additionally bends at the “elbow”, bringing the umbrella closer or closer to the rack, and also makes it possible to independently control the inclination of each dome.
In the shape of the dome, umbrellas are round, square, rectangular, oval, triangular, in the form of a petal, as well as original shapes. Individual models can be attached to the wall, fanning around the support pressed against the wall.
Umbrella support materials
Traditional materials for supports are:
- Expensive and durable tree (iroko, eucalyptus, Swedish pine or less prestigious, but more elastic ash)
- Aluminum (anodized, varnished or painted with powder paints)
- Very rarely fiberglass
- In cheap models – plastic
- Elite umbrellas also use bamboo
A distinctive feature of some umbrellas is the use of heavy ferrous metal. It is possible to note the modern tendency to displace wooden bases with aluminum imitations under a tree. Such supports, like knitting needles, are made hollow with a wall thickness of 1.2 mm for household and 2-5 mm for professional umbrellas. Racks made of wood are whole. They are impregnated with several layers of oil, reliably protecting from weathering, natural graying and preserving the beauty of the natural texture.
The frames of small umbrellas are sometimes produced in two parts, connected through a sleeve with a screw clamp or by the principle of the bayonet.
In the diameter of the support, there are from 25 to 130 mm for umbrellas with a central rack and from 75×75 to 200×200 mm in cross-section for cantilever umbrellas.
For professional umbrellas, the connecting hubs and all nodal elements are made of stainless (sometimes galvanized, varnished and even plasticized) steel, especially strong plastic composites, aluminum, and less often wood. For accessories, stainless steel is used mainly. Details of household umbrellas are made of inexpensive plastic, which determines their fragility.
Awning fabric is the main consumable. The most common material for the dome is acrylic. Depending on the initial preparation for UV radiation, it lasts from 2 to 5 years, individual species – even up to 10 seasons, after which the fabric fades.
In this case, the tents can be replaced.
To prevent the appearance of fungal stains, some manufacturers treat the material with special anti-mold compounds.
Oxford fabric is less commonly used. Some customers try to order umbrellas with her, due to their low cost. However, under the scorching sun, it sheds heavily in just 1 month. In general, this is the case when the avaricious pays twice. Awnings made of oxford fabric can be ordered if the density is at least 600den.
Domes differ in the number of spokes. 4-6 are characteristic mainly for household umbrellas, not designed for high wind loads. In addition to household purposes, they can be used in the greenhouse conditions of shopping centers. Professional models have 8, 10 or more (up to 40 in some umbrellas) spokes and are often equipped with a quick-change system without disassembling the umbrella.
In addition to quantity, pay attention to the material of the knitting needles. It can be high-strength steel, aluminum, strong wood, bamboo or fiberglass. The classic cross-section of knitting needles for professional umbrellas is 15×30 – 20×40 mm. Domes with a diameter of 6 m are reinforced with knitting needles of 20×80 mm.
At the top of some models, attentive customers might notice a hole covered more often with loose fabric or a second small dome. This is a specially provided valve or ventilation plug, which allows for a gust of wind to reduce pressure on the umbrella from below and avoid the greenhouse effect under the dome.
Umbrellas with a diameter of 3 or more meters must be supplied with such valves without fail, although they are also found with smaller models inexpensive models.
The vertically hanging edge of the dome, the shuttlecock (used as an optional accessory for a number of models), is not only a decorative element and serves to place advertising signs on it, but also partially softens the wind load.
Umbrella stability- types of clips and bases
An important characteristic of patio umbrellas is wind resistance. It depends both on the design of the umbrella and on the type of fixation. For professional models, manufacturers produce bases for mobile and stationary mounting. The latter is recommended on sea coasts.
All this, of course, does not apply to inexpensive and relatively small garden umbrellas. For them, plastic substrates filled with water are most often used. They are cheap enough. They are also available in large sizes, even holding umbrellas with lateral support. In aesthetics, such bases lose, but for a garden plot, they are completely alright.