{"id":1988,"date":"2024-07-30T22:20:02","date_gmt":"2024-07-30T22:20:02","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=1988"},"modified":"2024-07-30T22:20:03","modified_gmt":"2024-07-30T22:20:03","slug":"double-purchase-winch-crab","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/07\/30\/double-purchase-winch-crab\/","title":{"rendered":"DOUBLE PURCHASE WINCH CRAB"},"content":{"rendered":"\n

shows the schematic diagram of double purchase winch crab. In this device, velocity ratio is increased by using two pairs of gears. There are three axles as effort axle, intermediate, and load axle, two pinion gears as P<\/em>1<\/sub> and P<\/em>2<\/sub>, two spur gears as S<\/em>1<\/sub> and S<\/em>2<\/sub>. Pinion P<\/em>1<\/sub> mounted on effort axle, pinion P<\/em>2<\/sub> and spur gear S<\/em>1<\/sub> are mounted on the intermediate axle while spur gear S2<\/sub> is mounted on load axle.<\/p>\n\n\n\n

\"Figure<\/figure>\n\n\n\n

Figure 13.12<\/strong> Double Purchase Winch Crab<\/p>\n\n\n\n

Weight W<\/em> is attached to the string wound on the load axle while the effort is applied on the lever arm of the effort axle. Hence by rotating the lever, the pinion is rotated, which rotates the spur gear and pinion on intermediate shaft, the pinion on intermediate axle rotates the gear on load axle; in this way load W<\/em> gets lifted.<\/p>\n\n\n\n

When the lever arm rotates by one revolution, the effort axle and pinion P<\/em>1<\/sub> also moves by one revolution = 2\u03c0L<\/em><\/p>\n\n\n\n

As we know,<\/p>\n\n\n\n

\"Equation\"\/<\/figure>\n\n\n\n

The load axle S<\/em>2<\/sub> rotates by, \"equation\" revolution<\/p>\n\n\n\n

Hence, the distance moved by load <\/em>\"equation\"<\/p>\n\n\n\n

Distance moved by effort axle = 2\u03c0L<\/em><\/p>\n\n\n\n

where T<\/em>1<\/sub> is number of teeth on pinion P<\/em>1<\/sub>, T<\/em>2<\/sub> is number of teeth on spur gear S<\/em>1<\/sub>, T<\/em>3<\/sub> is number of teeth on pinion P<\/em>2<\/sub>, T<\/em>4<\/sub> is number of teeth on spur gear S<\/em>2<\/sub>, L<\/em> is length of lever arm, and r<\/em> is radius of load axle.<\/p>\n\n\n\n

\"Equation\"\/<\/figure>\n\n\n\n

Example 13.12:<\/strong> In a double purchase winch crab, the pinions have 15 and 45 teeth while spur wheels contain 60 and 90 teeth. The effort handle is 500 mm long while the effective diameter of the drum is 180 mm. If the efficiency of the winch is 45%, find the load that can be lifted with an effort of 125 N applied at the end of the handle.<\/p>\n\n\n\n

Solution:<\/p>\n\n\n\n

Given: T<\/em>1<\/sub> = 15, T<\/em>3<\/sub> = 45, T<\/em>2<\/sub> = 60, T<\/em>4<\/sub> = 90, L<\/em> = 500 mm, r<\/em> = 90 mm<\/p>\n\n\n\n

\"Equation\"\/<\/figure>\n\n\n\n
\"Equation\"\/<\/figure>\n\n\n\n

Example 13.13:<\/strong> A double purchase winch crab has the following specifications:<\/p>\n\n\n\n

   Effective diameter of load drum = 160 mm<\/p>\n\n\n\n

                         Length of handle = 360 mm<\/p>\n\n\n\n

         Number of teeth on pinions = 20 and 30<\/p>\n\n\n\n

  Number of teeth on spur wheels = 75 and 90<\/p>\n\n\n\n

When tested it was found that an effort of 90 N was required to lift a load of 1,800 N and an effort of 135 N was required to lift a load of 3,150 N. Determine (i) law of machine, (ii) probable effort to lift a load of 5,000 N, and (iii) efficiency in the above case.<\/p>\n\n\n\n

Solution:<\/p>\n\n\n\n

\"Equation\"\/<\/figure>\n\n\n\n
    \n
  1. Law of machine, P<\/em> = 0.033W<\/em> + 30<\/li>\n\n\n\n
  2. P<\/em>3<\/sub> = mW<\/em>3<\/sub> + C<\/em> or P<\/em>3<\/sub> = 0.033 \u00d7 5,000 + 30 = 196.5 N<\/li>\n\n\n\n
  3. \"equation\"<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    shows the schematic diagram of double purchase winch crab. In this device, velocity ratio is increased by using two pairs of gears. There are three axles as effort axle, intermediate, and load axle, two pinion gears as P1 and P2, two spur gears as S1 and S2. Pinion P1 mounted on effort axle, pinion P2 and spur gear S1 are mounted on the intermediate axle while spur […]<\/p>\n","protected":false},"author":1,"featured_media":1989,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[345],"tags":[],"class_list":["post-1988","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-lifting-machines"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/07\/download-17.jpeg","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/1988","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=1988"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/1988\/revisions"}],"predecessor-version":[{"id":1990,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/1988\/revisions\/1990"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/1989"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=1988"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=1988"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=1988"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}