Choosing the jack very serious matter. Since any failure of the hijack may lead to injury (knocked out teeth, broken arms, etc.)
How many copies have been broken around the bent rack jack! All squabbles Montagues and Capulets, as well as disputes tupo- ostrokonechnikov together and resting on a background of the arguments about whether to buy a farm jack and which of the two types of high-lift better.
But what is typical – the argument of the opposing sides is reduced to colorful life examples where profit is tightly intertwined with pictures born irrepressible human fontaziey. Well, perhaps we’ll leave the exploits of heroes, legends – akyns and try to objectively compare themselves jacks off-road, using an unbiased scientific approach.
Nowadays, there are commercially available hi-jack the two brands: American Hi-Lift and Russian «Sorokinstrument». Jeepers have experienced certain there will be Canadian Jack-All, but on the shelves and in the price lists they no longer find. Even during his active presence in the Russian market area of distribution «Canadians» It was not so wide to take them into account in this test. Today, they are more rare collectible, not a weapon «off-road work». As well as the hi-jacks of other manufacturers, never comes to us officially and fall in single copies. This is despite the fact that among the latter may be of interest to study the model (for example, Tiger Jack from the US «Maasdam Pow’r-Pull Inc.» – to them is given a lifetime warranty). In general, today we decided to stay only on the models that are available to Russian buyers.
«Hi-Lift Jack Company» It produces two types of rack jack. According to the manufacturer, «Red Series» completely made of iron, except for a steel arm, bolts and the bearing pin. AT «black» of the details, including the reference area, the upper eye and some leverage mechanism – steel. Reiki, according to the manufacturer, both versions are identical. Prices – almost the same (black model is $ 5 cheaper than similar in length red). Despite this, each color has its own supporters and, in the opinion of sellers, there are even regional preferences. Thus, Moscow is mainly buys red hi-lifts, and carry them to the Urals almost stopped – it asks only black. In short, and here and there find «his» color stronger.
Those who are trying to save money (regardless of geography), stop the choice on the hi-jack, which offers a network of shops «Sorokinstrument». They jack, previously sold under the name «Farm Jack»And now has become a «hi-jack»Worth about one and a half times cheaper «elevator». By design it is similar to overseas competitors, with the exception of nuances. Thus, the handle is made not folding, and as axes of the gear lever are not used bolts and nuts, and zashplintovat fingers. This rail to the sole, on the contrary, are bolted. In addition, this model handle end closed with a rubber cover, but the role of its latch upright perform two plates welded thereto. By the way, the practice shows that with time they unbend and cease to perform its function. Figure snap ring intended for the same purpose at «Americans»It showed itself much more reliable.
Since we are on «the national question»Dwell on it in more detail. The origin of the Hi-Lift jack, no one there is no doubt: the city of Bloomfield, Illinois, USA. Pedigree their competitors are not so clear. The passport, recently supplied to Sorokin’s hi-jack, stated: «Manufacturing companies Torin Jacks Inc., USA»And this despite the fact that earlier the same tools as the Dutch were sold! Although gossips will claim that they are punched in China, we, to avoid confusion in the terminology, let’s call Sorokin jacks «our»As they are sold under national brand.
How many differences?
For the test we took three of the long version of each model: HL-604, HL-605 and 5.8605. At first glance, the jacks are very similar. Close dimensions, similar design, the same principle of operation, and rail and at all interchangeable. Indeed, the profile dimensions of the subjects are very close, and the distance between the holes rails in all three instances, and did the same. It catches the eye unless the difference in design handles the representatives of competing brands and adapted exclusively for cable mounting stamped flat top eyelet at the HL-604. «Redhead American» and «our»On the contrary, are able to operate as a media (clips) because, being rotated across the rails, their powerful upper eye becomes a reliable stop. But there are nuances, so if «Sorokin» It is always in the eye «clamping» position (not particular configuration allows flip it otherwise), then iron Hi-Lift it without problems rotates around its axis, which makes both the transport and work as a winch.
The first test – Toyota LC heavy lifting on a country road… All three jack certainly coped with this task. Wheel hung out at a sufficient height to change it, and the machine while retaining stability. With a further rise another thirty centimeters in all cases, the balance was broken and the car slowly crawled to the side. In general, all as it should be on an uneven surface. However, there revealed interesting moments. Thus, the mechanism of inherited us «black American» He refused to move freely up the rail and had to «sway» even without a load, while «Sorokin» It began toppling gum handle. However, both we assigned to individual shortcomings of specific instances (it is curable in the right hands). However, it is possible to indirectly judge the stability of quality and culture of production. But peeling paint shreds «lifts» and drop-down at the fingertips of support pins «Pharma» – This, alas, statistics, repeated at almost every instance. If we talk about usability, the big difference between the three models we have not noticed. Is that effort on the handle while lifting vehicle «our» hi-jack subjectively seemed little more than that «Americans»And the work mechanism – a little tougher.
|Max. poema height, mm||1282||1343||1277|
|Min. height. Pick-up||115||123||112|
|* Handle length, mm||835||865 * (845)||830|
|The length of the beak, mm||118||114||116|
|The size of the supports. playground||180h102||180h120||177h112|
* Mounting on the axis
** Without rubber boot
The validity of our perceptions confirmed and impartial machinery… Measurements in a special laboratory NITSIAMT shown that the linkage of each of the hi-jack the different reports on the lifting platform the force exerted by the handle. The maximum ratio turned out to be the black (steel) Hi-Lift, a minimum – at «Sorokin». The difference was about 15%. This characteristic of red (iron) «American» It is located approximately in the middle. Along the way, it identifies some of the characteristics of the non-linearity transformation efforts in all three jacks. The more driven; handle, the higher is the transmission ratio of the entire mechanism. Apparently, this is due to a change in the force vector during the power stroke handles and levers.
Along the way, we spent one more measurement: a maximum force can develop with the jack man. Tellingly, in each approach were obtained different results, even in the same test. Lifting force proved to be very sensitive to how costs «operator»He holds the handle, and even more so as it presses. However much we tried, no one has managed to raise more than 2.5 tons. According to our calculations, for the taking this weight would require athlete weighing about quintal and that of our company to this day turned out …
Now try to guess what will make normal dzhiper if he will need to raise more than allow their own. Otgadok two. He calls for help or other jeepers and they will take the weight together, or simply lengthen the handle and win a piece of pipe yourself. Yes, despite all the warnings in the instructions to the jack, so you can not do that, that’s all they do. And what to do if another chance for salvation from the mud there? This situation we have modeled by extending the handle up to 190 cm. The laws of physics have not lied: work has become several times easier. You can now find the limit of carrying capacity jacks (in all cases to the manufacturer at three tons)…
Once again we press jacks on the line at a special stand with weights and now we press on the handle as long as something is not broken. All three mechanisms are exposed at the same height – 1160 mm from the plane of the beak (simply speaking, the top of the rail, a few clicks to a maximum), and the handle extended. It is in these situations is usually bent and broken slats mechanisms at Off Road… From dzhiperskih realities of our laboratory experience is different only in that we have long exhibited a jack vertically on a flat plane, simulating an ideal situation.
BREAK – DO NOT BUILD
The first went to «chopping block» Black Hi-Lift. When the load on the beak crept up to around 2750 kg, it became visually noticeable transverse deflection rail. However, with increasing pressure on the arm lifting weight continued to increase, and soon crossed the scales three-ton mark. Deformation of the rail became more noticeable, slightly bent handle, but Jack continued to do their work. Only at around 3300 there was a roar, something flew by my ear, and hi-jack collapsed. It turned out, could not stand the bolt, serving as a reference axis of the intermediate lever mechanism. Arm bent steel plate, just cut it as a pair of scissors in two places (one of the pieces and went to the coast). The mechanism pereschelknulsya position «downhill»And Jack lost his balance. Be it car, she would have fallen! As for the rail, then despite the very noticeable bend in the process of recovery, she returned to its original state and once again become perfectly straight…
Now turn red «elevator». In his account it was suspected that the thick solid lever will not be able to quickly cut through the jack bolt and last longer (of course, if you do not break that detail). However, on the behavior under extreme loads this instance were similar with their black counterparts. At about the same numbers on the scales appeared transverse deformation of the rack and began to gradually increase. However, bending the handle, we have not waited. But the familiar bolt broke, but, as expected, a little later. The mark of 3,500 kg. The mechanism pereschelknulsya and fell down. What to do in such a situation dzhiper in the woods? Finds first got red-hot pin, a suitable diameter, and again gets a workable hi-jack. However, the instruction to the Hi-Lift expressly prohibits such repairs, demanding to put only original spare parts from the repair kit. The fact that the fracture of the bolt with the calculated strength is programmed as a kind of fuse manufacturers is not capable of more serious damage the jack when overloaded. In both cases it worked. The other obvious defects, allow to use jacks are not visible.
Now turn «Sorokinstrumenta». He stands on the site of a thicker bolt pin. Interestingly, he also serves as a fuse or we will see a different scenario? Davim! After 2600 kg rake a little bent, but not across, and… on the long side. Booster to almost 2800 kg – and then acquires fluidity handle. When the load drops back to 2600 kg, but Jack keeps his balance and continues to stand as if nothing had happened. The handle is bent a semicircle, and the sense or per gram. Soak Jack claimed three tonnes, this option «overdrive» It would be the best – the most secure, while preserving the visual and further a field instrument operation without any need for urgent repairs (rail, as in the two previous cases, after unloading straightened).
So, first of flogging all three instances transferred in general firmly. «The Americans» after a moment’s ready to go back to the repair order, «our», Though with the handle of the curve, but fully functional. So what we need load to happen «irreparable»?
Replying to a question, given the final test. The powerful, rough and visible… We decided to just load the mighty press jacks, resting the heel of one plate and the other beak. We print the mechanisms almost the most complete course – 1260 mm, and before the start of the experiment, fix each of the jacks in the press, strictly observing the vertical and horizontal position.
Crunching – And in half!
I must say the results of this test, we have greatly puzzled. The black «elevator» It was the most resistant. Rake bent, but kept very long. Only with a load of 3600 kg there was a loud bang, like a shot, – and jack formed across the rails. Something like we expected. But the behavior of iron «elevator» It puts us into a dead end – he simply and gently formed when the load reaches only… 1700 kg. «Sorokinstrument» was not much stronger, his rake broke load 1750 kg, and there was also, but more dramatically.
In an attempt to explain what happened, or rather, a sinking two red competitors, we stopped for two versions. First, that during the previous test, we almost broke the limit of stability of rods, and took them imperceptible eye irreversible deformation, perhaps even with a change in the structure of the metal. Therefore, correctly load the fuse only in «combined» Hi-Lift. The second version – Press the motion in two cases violated the provisions of the jack and is moved relative to initially put up the level and plumb position. That is actually gained by continuing to increase the slope of the load by simulating a situation where the car is already beginning to overwhelm, but it is still rising. Such a significant reduction in load-carrying capacity in this case is due to pressure changes in the vector.
Which leads to the conclusion? In our opinion, the situation is quite clear. You can break it. But even if we take into account the likelihood of differences in the quality of different batches of the same brand, the strength at the Hi-Lift objectively higher than «Sorokin». At the same time for the majority of off-road vehicles can use any version of our trio, as well as no one we would not recommend that for pulling out of the truck. Regarding the specific application, they are also similar: to remember that the warning to replace the safety bolts and extension handles instructions are not written for the sake of the elegant style.
But the rule has a bent rail makes no sense. It’s like a rule bent nail. Ideal her flat for the second time not to do. Moreover, during the occurrence of irreversible deformation is broken and the metal structure becomes much less load.
Comment on the results of experiments and conduct spectral analysis of the material strips we asked metallurgists from the Institute of Inorganic Materials. Academician Bochvar. Both of our assumptions about the differences sustained by each of the hi-jack loads in the first and second experiments, experts found faithful. The conclusion that emerged after the first test metal fatigue, according to the authoritative opinion, the ideal laboratory conditions suitable rather than a suspicion of bias test sample as set out in the press.
With regard to the material from which the slats are made, the result of analysis we were surprised. The chemical composition of all three rails have been very close, though not absolutely identical. But the material turned out to be steel. And the most common, non-alloy. Neither of which iron is claimed by both the producers in the carbon content of less than 0.5%, according to the metallurgists, can not be considered. Cast irons must include this element in the framework of 2–4%. But it’s good – more rigid, but brittle iron is unlikely to withstand a much greater load, but with the strain of rake would not bent and broke in half, which, in our opinion, in any case, much more dangerous. In addition, when random collisions of rail inevitable during the operation of the jack, the metal it might start to crumble.
If we talk about the differences between the load of seasoned jacks different manufacturers, then the strength of similar chemical composition determined by only one rail – features material processing, in which the steel gets extra strength. This is where the hidden secret of the utmost stability of the hi-jack.
The chemical composition of rails (mass fraction,%)
|Iron||gt; 98||gt; 98||gt; 98|
|Nickel||0,044||lt; 0.01||lt; 0.01|
|Sulfur||lt; 0.01||lt; 0.01||lt; 0.01|
|Aluminum||lt; 0.003||lt; 0.003||lt; 0.003|
First Source and author of the article "Non-Euclidean geometry" http://www.off-road-drive.ru
Aleev Sergei, Eugene Konstantinov5 december 2011 at 00:00