Descripción: Machine drawing and Industrial drafting
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Introduction Roe (1916) credits James Nasmyth Nasmyth with the invention of the shaper in 1836. But the asic function of a shaper is sti!! sound" too!in# for them is minima! and very cheap to reproduce" and they are simp!e and roust in construction$ ma%in# their repair and up%eep easi!y achieva!e. &hus they are sti!! popu!ar in many machine shops$ from 'oin from 'oin# # shops or shops or repair shops to shops to too! and die shops$ shops$ where on!y one or a few pieces are reuired to e produced and the a!ternative methods are cost or too!in#intensive.
Shaper * shaper is a type of machine too! that uses !inear re!ative motion etween the wor% piece and a sin#!epoint cuttin# too! to too! to machine machine a a !inear too! path. +ts cut is ana!o#ous to that of a !athe$ !athe$ e,cept that it is (archetypa!) !inear instead of he!ica!.
Types -hapers are main!y c!assified as hi#her$ drawcut$ horionta!$ universa!$ vertica!$ #eared$ cran%$ hydrau!ic$ contour and trave!in# head. &he horionta! arran#ement is the most common. /ertica! shapers are #enera!!y fitted with a rotary ta!e to ena!e curved surfaces to e machined (same idea as in he!ica!). &he vertica! shaper is essentia!!y the same thin# as a slitter (s!ottin# machine)$ a!thou#h technica!!y a distinction can e made if one defines a true vertica! shaper as a machine whose s!ide can e moved from the vertica!. * s!itter is fi,ed in the vertica! p!ane. -ma!! shapers have een successfu!!y made to operate y hand power. *s sie increases$ the mass of the machine and its power reuirements increase$ and it ecomes necessary to use a motor or other supp!y of mechanica! power. &his motor drives a mechanica! arran#ement (usin# a pinion #ear$ u!! #ear$ and cran%$ or a chain over sproc%ets) or a hydrau!ic motor that supp!ies the necessary movement via hydrau!ic cy!inders.
Working Principle &he 'o is ri#id!y fi,ed on the machine ta!e. &he sin#!e point cuttin# too! he!d proper!y in the too! post is mounted on a reciprocatin# ram. &he reciprocatin# motion of the ram is otained y a uic% return motion mechanism. *s the ram reciprocates$ the too! cuts the materia! durin# its forward stro%e. 0urin# return$ there is no cuttin# action and this stro%e is ca!!ed the id!e stro%e. &he forward and return stro%es constitute one operatin# cyc!e of the shaper.
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i#ure 2 shaper machine
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Construction &he main parts of the -haper machine is Base$ Body (i!!ar$ rame$ 4o!umn)$ 4ross rai!$ Ram and too! head (&oo! ost$ &oo! -!ide$ 4!amper Bo, B!oc%).
Base &he ase is a heavy cast iron castin# which is fi,ed to the shop f!oor. +t supports the ody frame and the entire !oad of the machine. &he ase asors and withstands virations and other forces which are !i%e!y to e induced durin# the shapin# operations.
Body (Pillar, Frame, column) +t is mounted on the ase and houses the drive mechanism compressin# the main drives$ the #ear o, and the uic% return mechanism for the ram movement. &he top of the ody provides #uide ways for the ram and its front provides the #uide ways for the cross rai!.
Cross rail &he cross rai! is mounted on the front of the ody frame and can e moved up and down. &he vertica! movement of the cross rai! permits 'os of different hei#hts to e accommodated e!ow the too!. -!idin# a!on# the cross rai! is a sadd!e which carries the wor% ta!e.
Ram and tool head &he ram is driven ac% and forth in its s!ides y the s!otted !in% mechanism. &he ac% and forth movement of ram is ca!!ed stro%e and it can e ad'usted accordin# to the !en#th of the wor% piece to emachined.
peration * shaper operates y movin# a hardened cuttin# too! ac%wards and forwards across the wor% piece. 5n the return stro%e of the ram the too! is !ifted c!ear of the wor% piece$ reducin# the cuttin# action to one direction on!y. &he wor% piece mounts on a ri#id$ o,shaped ta!e in front of the machine. &he hei#ht of the ta!e can e ad'usted to suit this wor% piece$ and the ta!e can traverse sideways underneath the reciprocatin# too!$ which is mounted on the ram. &a!e motion may e contro!!ed manua!!y$ ut is usua!!y advanced y automatic feed mechanism actin# on the feed screw. &he ram s!ides ac% and forth aove the wor%. *t the front end of the ram is a vertica! too! s!ide that may e ad'usted to either side of the vertica! p!ane a!on# the stro%e a,is. &his too!s!ide ho!ds the c!apper o, and too! post$ from which the too! can e positioned to cut a strai#ht$ f!at surface on the top of the wor% piece. &he too!s!ide permits feedin# the too! downwards to deepen a cut. &his ad'ustai!ity$ coup!ed with the use of specia!ied cutters and too! ho!ders$ ena!e the operator to cut interna! and e,terna! #ear tooth profi!es$ spines$ dovetai!s$ and %eyways.
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&he ram is ad'usta!e for stro%e and$ due to the #eometry of the !in%a#e$ it moves faster on the return (noncuttin#) stro%e than on the forward$ cuttin# stro%e. &his action is via a s!otted !in% or hitworth !in% .
Speci!ication o! shaper &he sie of a shaper is determined y the ma,imum !en#th of stro%e or cut it can ma%e. &he usua! sie ran#es from 17 to 9 mm. &he !en#th of stro%e indicates$ in addition to the #enera! sie of the machine$ the sie of a cue that can e he!d and p!aned + the shaper. &hus in a : mm shaper the !en#th of stro%e may e ad'usted from to : mm$ the cross feed ad'usted of the ta!e wi!! e : mm and the e,treme ottom position of the cross rai! wi!! permit the ta!e to accommodate a wor% piece : mm hi#h. &he !en#th of stro%e of a shaper mere!y indicates the overa!! sie of the shaper other particu!ars$ such as the type of drive ; e!t or individua! motor drive$ power input$ f!oor space reuired$ wei#ht of the machine$ cuttin# to return stro%e ratio$ numer and amount of feed etc. are a!so sometimes necessary.
"echanism in shaper +n order to reduce the time wasted durin# the return noncuttin# stro%e$ shaping machines are fitted with a #uick$return mechanism $ usua!!y of the cran% and s!otted!in% desi#n.
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&his is shown dia#rammatica!!y in i#s. . &he ram is driven y a s!otted !in% which pivots at its !ower end and is attached to the ram y a !oose connectin# !in% at its upper end. &he s!otted !in% en#a#es with the cran% pin mounted on the drivin# whee! which rotates at constant speed and causes the !in% to osci!!ate and the ram to reciprocate. * #earo, contro!s the speed of the drivin# pinion$ thus providin# a ran#e of speeds for the ram. * shaper is ana!o#ous to a p!aner $ ut sma!!er$ and with the cutter ridin# a ram that moves aove a stationary wor% piece$ rather than the entire wor% piece movin# eneath the cutter. &he ram is moved ac% and forth typica!!y y a cran% inside the co!umn" actuated shapers a!so e,ist.
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*ssumin# the drivin# whee! is rotatin# in a c!oc%wise direction$ then with the ram at the start of the cuttin# stro%e the centre!ine of the s!otted !in% is tan#entia! with the path of the cran% pin shown at point : on dia#ram. *s the whee! rotates the ram moves forward unti! the !in% a#ain ecomes tan#entia!$ shown at point 1. urther rotation of the drivin# whee! withdraws the ram to its startin# position at point :. $ is the cuttin# stro%e$ and that from 1 to : in this e,amp!e$ 1:>$ is the return stro%e$ #ivin# a :;1 ratio. *s the !en#th of the stro%e is increased or decreased the ratio of the cuttin# time to the return time varies *s the drivin# disc is connected to the u!! #ear the ta!e feed movement is effected when the u!! #ear or the divin# disc rotates throu#h ha!f of therevo!ution$ i.e.$ durin# return stro%e on!y. Rotation throu#h other ha!f imparts no feedmoveme nt. &o reverse the direction of rotation of ratchet whee! and conseuent!y the feed$ a %no ? on the top of the paw! = after removin# the pin : is rotated throu#h 18 de#rees. &he amount of feed may e a!tered y shiftin# the position of cran% pin 9 with respect to the centre. @reater the throw of eccentricity$ more wi!! e the roc%in# movement of the arm and the paw! wi!! pass throu#h three or four teeth on the whee! at a time impartin# #reater feed movement.
%ses &he shaper is a machine too! used primari!y for; 1. roducin# a f!at or p!ane surface which may e in a horionta!$ a vertica! or an an#u!ar p!ane. :. Aa%in# s!ots$ #rooves and %eyways 3. roducin# contour of concave?conve, or a comination of these. =. +t is even possi!e to oviate wire 0A wor% in some cases. -tartin# from a dri!!ed or cored ho!e$ a shaper with a orin#ar type too! can cut interna! features that donCt !end themse!ves to mi!!in# or orin# (such as irre#u!ar!y shaped ho!es with ti#ht corners)
Conclusion -o the shaper machine is very needed roducin# a f!at or p!ane surface which may e in a horionta!$ a vertica! or an an#u!ar p!ane
