Why are mechanical brakes often used on cranes? | Numerade (2024)

`); let searchUrl = `/search/`; history.forEach((elem) => { prevsearch.find('#prevsearch-options').append(`

${elem}

`); }); } $('#search-pretype-options').empty(); $('#search-pretype-options').append(prevsearch); let prevbooks = $(false); [ {title:"Recently Opened Textbooks", books:previous_books}, {title:"Recommended Textbooks", books:recommended_books} ].forEach((book_segment) => { if (Array.isArray(book_segment.books) && book_segment.books.length>0 && nsegments<2) { nsegments+=1; prevbooks = $(`

  • ${book_segment.title}
  • `); let searchUrl = "/books/xxx/"; book_segment.books.forEach((elem) => { prevbooks.find('#prevbooks-options'+nsegments.toString()).append(`

    ${elem.title} ${ordinal(elem.edition)} ${elem.author}

    `); }); } $('#search-pretype-options').append(prevbooks); }); } function anon_pretype() { let prebooks = null; try { prebooks = JSON.parse(localStorage.getItem('PRETYPE_BOOKS_ANON')); }catch(e) {} if ('previous_books' in prebooks && 'recommended_books' in prebooks) { previous_books = prebooks.previous_books; recommended_books = prebooks.recommended_books; if (typeof PREVBOOKS !== 'undefined' && Array.isArray(PREVBOOKS)) { new_prevbooks = PREVBOOKS; previous_books.forEach(elem => { for (let i = 0; i < new_prevbooks.length; i++) { if (elem.id == new_prevbooks[i].id) { return; } } new_prevbooks.push(elem); }); new_prevbooks = new_prevbooks.slice(0,3); previous_books = new_prevbooks; } if (typeof RECBOOKS !== 'undefined' && Array.isArray(RECBOOKS)) { new_recbooks = RECBOOKS; for (let j = 0; j < new_recbooks.length; j++) { new_recbooks[j].viewed_at = new Date(); } let insert = true; for (let i=0; i < recommended_books.length; i++){ for (let j = 0; j < new_recbooks.length; j++) { if (recommended_books[i].id == new_recbooks[j].id) { insert = false; } } if (insert){ new_recbooks.push(recommended_books[i]); } } new_recbooks.sort((a,b)=>{ adate = new Date(2000, 0, 1); bdate = new Date(2000, 0, 1); if ('viewed_at' in a) {adate = new Date(a.viewed_at);} if ('viewed_at' in b) {bdate = new Date(b.viewed_at);} // 100000000: instead of just erasing the suggestions from previous week, // we just move them to the back of the queue acurweek = ((new Date()).getDate()-adate.getDate()>7)?0:100000000; bcurweek = ((new Date()).getDate()-bdate.getDate()>7)?0:100000000; aviews = 0; bviews = 0; if ('views' in a) {aviews = acurweek+a.views;} if ('views' in b) {bviews = bcurweek+b.views;} return bviews - aviews; }); new_recbooks = new_recbooks.slice(0,3); recommended_books = new_recbooks; } localStorage.setItem('PRETYPE_BOOKS_ANON', JSON.stringify({ previous_books: previous_books, recommended_books: recommended_books })); build_popup(); } } var whiletyping_search_object = null; var whiletyping_search = { books: [], curriculum: [], topics: [] } var single_whiletyping_ajax_promise = null; var whiletyping_database_initial_burst = 0; //number of consecutive calls, after 3 we start the 1 per 5 min calls function get_whiletyping_database() { //gets the database from the server. // 1. by validating against a local database value we confirm that the framework is working and // reduce the ammount of continuous calls produced by errors to 1 per 5 minutes. return localforage.getItem('whiletyping_last_attempt').then(function(value) { if ( value==null || (new Date()) - (new Date(value)) > 1000*60*5 || (whiletyping_database_initial_burst < 3) ) { localforage.setItem('whiletyping_last_attempt', (new Date()).getTime()); // 2. Make an ajax call to the server and get the search database. let databaseUrl = `/search/whiletype_database/`; let resp = single_whiletyping_ajax_promise; if (resp === null) { whiletyping_database_initial_burst = whiletyping_database_initial_burst + 1; single_whiletyping_ajax_promise = resp = new Promise((resolve, reject) => { $.ajax({ url: databaseUrl, type: 'POST', data:{csrfmiddlewaretoken: "Tb68rRTelSUWdlKR3t2QnBsdiOEUTSH6WVuRmfPA4ZyEGocWf2aa8T2C7GjOwprk"}, success: function (data) { // 3. verify that the elements of the database exist and are arrays if ( ('books' in data) && ('curriculum' in data) && ('topics' in data) && Array.isArray(data.books) && Array.isArray(data.curriculum) && Array.isArray(data.topics)) { localforage.setItem('whiletyping_last_success', (new Date()).getTime()); localforage.setItem('whiletyping_database', data); resolve(data); } }, error: function (error) { console.log(error); resolve(null); }, complete: function (data) { single_whiletyping_ajax_promise = null; } }) }); } return resp; } return Promise.resolve(null); }).catch(function(err) { console.log(err); return Promise.resolve(null); }); } function get_whiletyping_search_object() { // gets the fuse objects that will be in charge of the search if (whiletyping_search_object){ return Promise.resolve(whiletyping_search_object); } database_promise = localforage.getItem('whiletyping_database').then(function(database) { return localforage.getItem('whiletyping_last_success').then(function(last_success) { if (database==null || (new Date()) - (new Date(last_success)) > 1000*60*60*24*30 || (new Date('2023-04-25T00:00:00')) - (new Date(last_success)) > 0) { // New database update return get_whiletyping_database().then(function(new_database) { if (new_database) { database = new_database; } return database; }); } else { return Promise.resolve(database); } }); }); return database_promise.then(function(database) { if (database) { const options = { isCaseSensitive: false, includeScore: true, shouldSort: true, // includeMatches: false, // findAllMatches: false, // minMatchCharLength: 1, // location: 0, threshold: 0.2, // distance: 100, // useExtendedSearch: false, ignoreLocation: true, // ignoreFieldNorm: false, // fieldNormWeight: 1, keys: [ "title" ] }; let curriculum_index={}; let topics_index={}; database.curriculum.forEach(c => curriculum_index[c.id]=c); database.topics.forEach(t => topics_index[t.id]=t); for (j=0; j

    Solutions
  • Textbooks
  • `); } function build_solutions() { if (Array.isArray(solution_search_result)) { const viewAllHTML = userSubscribed ? `View All` : ''; var solutions_section = $(`
  • Solutions ${viewAllHTML}
  • `); let questionUrl = "/questions/xxx/"; let askUrl = "/ask/question/xxx/"; solution_search_result.forEach((elem) => { let url = ('course' in elem)?askUrl:questionUrl; let solution_type = ('course' in elem)?'ask':'question'; let subtitle = ('course' in elem)?(elem.course??""):(elem.book ?? "")+"    "+(elem.chapter?"Chapter "+elem.chapter:""); solutions_section.find('#whiletyping-solutions').append(` ${elem.text} ${subtitle} `); }); $('#search-solution-options').empty(); if (Array.isArray(solution_search_result) && solution_search_result.length>0){ $('#search-solution-options').append(solutions_section); } MathJax.typesetPromise([document.getElementById('search-solution-options')]); } } function build_textbooks() { $('#search-pretype-options').empty(); $('#search-pretype-options').append($('#search-solution-options').html()); if (Array.isArray(textbook_search_result)) { var books_section = $(`
  • Textbooks View All
  • `); let searchUrl = "/books/xxx/"; textbook_search_result.forEach((elem) => { books_section.find('#whiletyping-books').append(` ${elem.title} ${ordinal(elem.edition)} ${elem.author} `); }); } if (Array.isArray(textbook_search_result) && textbook_search_result.length>0){ $('#search-pretype-options').append(books_section); } } function build_popup(first_time = false) { if ($('#search-text').val()=='') { build_pretype(); } else { solution_and_textbook_search(); } } var search_text_out = true; var search_popup_out = true; const is_login = false; const user_hash = null; function pretype_setup() { $('#search-text').focusin(function() { $('#search-popup').addClass('show'); resize_popup(); search_text_out = false; }); $( window ).resize(function() { resize_popup(); }); $('#search-text').focusout(() => { search_text_out = true; if (search_text_out && search_popup_out) { $('#search-popup').removeClass('show'); } }); $('#search-popup').mouseenter(() => { search_popup_out = false; }); $('#search-popup').mouseleave(() => { search_popup_out = true; if (search_text_out && search_popup_out) { $('#search-popup').removeClass('show'); } }); $('#search-text').on("keyup", delay(() => { build_popup(); }, 200)); build_popup(true); let prevbookUrl = `/search/pretype_books/`; let prebooks = null; try { prebooks = JSON.parse(localStorage.getItem('PRETYPE_BOOKS_'+(is_login?user_hash:'ANON'))); }catch(e) {} if (prebooks && 'previous_books' in prebooks && 'recommended_books' in prebooks) { if (is_login) { previous_books = prebooks.previous_books; recommended_books = prebooks.recommended_books; if (prebooks.time && new Date().getTime()-prebooks.time<1000*60*60*6) { build_popup(); return; } } else { anon_pretype(); return; } } $.ajax({ url: prevbookUrl, method: 'POST', data:{csrfmiddlewaretoken: "Tb68rRTelSUWdlKR3t2QnBsdiOEUTSH6WVuRmfPA4ZyEGocWf2aa8T2C7GjOwprk"}, success: function(response){ previous_books = response.previous_books; recommended_books = response.recommended_books; if (is_login) { localStorage.setItem('PRETYPE_BOOKS_'+user_hash, JSON.stringify({ previous_books: previous_books, recommended_books: recommended_books, time: new Date().getTime() })); } build_popup(); }, error: function(response){ console.log(response); } }); } $( document ).ready(pretype_setup); $( document ).ready(function(){ $('#search-popup').on('click', '.search-view-item', function(e) { e.preventDefault(); let autoCompleteSearchViewUrl = `/search/autocomplete_search_view/`; let objectUrl = $(this).attr('href'); let selectedId = $(this).data('objid'); let searchResults = []; $("#whiletyping-solutions").find("a").each(function() { let is_selected = selectedId === $(this).data('objid'); searchResults.push({ objectId: $(this).data('objid'), contentType: $(this).data('contenttype'), category: $(this).data('category'), selected: is_selected }); }); $("#whiletyping-books").find("a").each(function() { let is_selected = selectedId === $(this).data('objid'); searchResults.push({ objectId: $(this).data('objid'), contentType: $(this).data('contenttype'), category: $(this).data('category'), selected: is_selected }); }); $.ajax({ url: autoCompleteSearchViewUrl, method: 'POST', data:{ csrfmiddlewaretoken: "Tb68rRTelSUWdlKR3t2QnBsdiOEUTSH6WVuRmfPA4ZyEGocWf2aa8T2C7GjOwprk", query: $('#search-text').val(), searchObjects: JSON.stringify(searchResults) }, dataType: 'json', complete: function(data){ window.location.href = objectUrl; } }); }); });
    Why are mechanical brakes often used on cranes? | Numerade (2024)

    FAQs

    Why are mechanical brakes often used on cranes? | Numerade? ›

    The mechanical load

    mechanical load
    Mechanical load is the physical stress on a mechanical system or component leading to strain. Loads can be static or dynamic. Some loads are specified as part of the design criteria of a mechanical system.
    https://en.wikipedia.org › wiki › Mechanical_load
    brake is a key component of crane safety. It serves as a secondary braking mechanism of the crane hoist, controlling the lowering speeds of rated loads and preventing loads from free falling.

    What is the purpose of a mechanical brake? ›

    Mechanical brakes function via force delivered to a body in rotary or linear motion, such as an axle, shaft, or wheel, to slow or stop motion. Mechanical brakes are often in an assembly with a mechanical clutch for engaging and disengaging shafts.

    What is the advantage of dynamic brakes over mechanical brakes? ›

    Friction wears down mechanical brake pads. But dynamic braking minimizes the use of mechanical brakes, thus reducing wear and tear and extending the life of brake components.

    Which of the following is an advantage of mechanical type brakes? ›

    Mechanical type brakes have an advantage in that they can hold a suspended load.

    What are the three methods that can be used to provide braking for a motor? ›

    Read on to learn about the three types of systems and when they're applicable.
    • Regenerative Braking. Regenerative braking is used when the driven load causes the DC motor to run at speeds higher than its no-load speed. ...
    • Dynamic Braking. ...
    • Plugging.
    Sep 28, 2020

    What is the mechanical load brake on a crane? ›

    The mechanical load brake is a key component of crane safety. It serves as a secondary braking mechanism of the crane hoist, controlling the lowering speeds of rated loads and preventing loads from free falling.

    Why mechanical brakes are better than hydraulic? ›

    Advantages and disadvantages of mechanical disc brakes

    Compared to rim brakes, mechanical disc brakes provide reliable stopping power in a wide range of weather conditions, including rain and mud. They are also generally easier to maintain than hydraulic disc brakes, as they don't require bleeding.

    What are the drawbacks of mechanical braking systems? ›

    The wear and friction caused by the working surface areas are quite severe. Thus, the longevity of a mechanical braking system between maintenance depends heavily on the type of material used to line the pad or shoe.

    What is the main advantage of a mechanical drum brake? ›

    The main advantage of drum brakes is their low cost, in addition to being a very effective and long lasting system. Therefore, unlike disc brakes, the price of drum brake components is much lower than some of the components found in the market for disc brakes. That's a big difference between disc brake and drum brake.

    What is one advantage of hydraulic brakes over mechanical brakes? ›

    Hydraulic disk brakes also provide more braking power because they have a greater contact area, which supports heat dissipation. They also rarely fail, making them reliable at high speeds and work better compared to mechanical brakes in wet and muddy conditions.

    What is the difference between a hydraulic and a mechanical brake? ›

    Mechanical and Hydraulic brakes require different types of maintenance work. Mechanical brakes require maintenance due to the cables stretching and the fact that the pads start to wear out. Hydraulic brakes require maintenance after the brake pads are all completely worn out.

    Can you change mechanical disc brakes to hydraulic? ›

    You can't just “connect” a mechanical cable to a hydraulic system. You'd have to upgrade the shifters/brake levers (“brifters”) to ones which are made for hydraulic brakes. Unfortunately brifters are the most expensive part of road groupsets, so this would be quite an expensive upgrade.

    What is the efficiency of mechanical brakes? ›

    Are mechanical brakes usually efficient? Mechanical brakes are efficient to the extent they use friction to convert rotational hub motion into heat. The more heat generated, the more “efficient” the brakes. And the faster the system can dissipate that heat, the longer they will last.

    What is the mechanical braking method? ›

    Mechanical braking system:

    It is the type of braking system in which the brake force applied on the brake pedal is carried to the final brake drum or disc rotor by the various mechanical linkages like cylindrical rods, fulcrums, springs etc. In order to stop the vehicle.

    What is the most efficient method of motor braking? ›

    The most economical method of electrical braking is regenerative braking. Regenerative braking: In this type braking back emf Eb is greater than the supply voltage V, which reverses the direction of the motor armature current. The motor begins to operate as an electric generator.

    What is the most efficient braking technique? ›

    The pivot technique is the easiest method to smoothly and consistently reduce your car's speed. Here's how to brake using the pivot technique: Place your right foot on the brake pedal with your heel on the car floor, so only the front part of your foot touches the pedal.

    Why are mechanical brakes used in parking? ›

    The parking brake in most vehicles is still completely mechanical. Traditionally engaged by pulling a lever, the cables manually engage part of the car's braking system, usually the rear disk or drum brakes. The mechanical nature allows the driver to apply the brake even if the main hydraulic brake system fails.

    What is the purpose of braking mechanism? ›

    It allows the driver to control the vehicle's speed and bring it to a safe stop when required, preventing accidents and collisions. The braking system is designed to convert the vehicle's kinetic energy into thermal energy. It contains several parts, including brake pads, brake rotors, calipers, and brake fluid.

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