第 49 节
作者:铲除不公      更新:2021-03-08 19:38      字数:9322
  secured this invention in 1801; he also proposed sundry improvements
  in the boilers; as well as modifications in various parts of the
  engine; with the object of effecting greater simplicity and
  directness of action。
  In his patent of 1802; we find Bramah making another great stride in
  mechanical invention; in his tools 〃for producing straight; smooth;
  and parallel surfaces on wood and other materials requiring truth; in
  a manner much more expeditious and perfect than can be performed by
  the use of axes; saws; planes; and other cutting instruments used by
  hand in the ordinary way。〃  The specification describes the object of
  the invention to be the saving of manual labour; the reduction in the
  cost of production; and the superior character of the work executed。
  The tools were fixed on frames driven by machinery; some moving in a
  rotary direction round an upright shaft; some with the shaft
  horizontal like an ordinary wood…turning lathe; while in others the
  tools were fixed on frames sliding in stationary grooves。  A
  wood…planing machine*
  'footnote。。。
  Sir Samuel Bentham and Marc Isambard Brunel subsequently
  distinguished themselves by the invention of wood…working machinery;
  full accounts of which will be found in the Memoirs of the former by
  Lady Bentham; and in the Life of the latter by Mr。 Beamish。
  。。。'
  was constructed on the principle of this invention at Woolwich
  Arsenal; where it still continues in efficient use。  The axis of the
  principal shaft was supported on a piston in a vessel of oil; which
  considerably diminished the friction; and it was so contrived as to
  be accurately regulated by means of a small forcing…pump。  Although
  the machinery described in the patent was first applied to working on
  wood; it was equally applicable to working on metals; and in his own
  shops at Pimlico Bramah employed a machine with revolving cutters to
  plane metallic surfaces for his patent locks and other articles。  He
  also introduced a method of turning spherical surfaces; either convex
  or concave; by a tool moveable on an axis perpendicular to that of
  the lathe; and of cutting out concentric shells by fixing in a
  similar manner a curved tool of nearly the same form as that employed
  by common turners for making bowls。  〃In fact;〃 says Mr。 Mallet;
  〃Bramah not only anticipated; but carried out upon a tolerably large
  scale in his own worksfor the construction of the patent hydraulic
  press; the water…closet; and his locksa surprisingly large
  proportion of our modern tools。〃*
  'footnote。。。
  〃Record of the International Exhibition; 1862。〃  Practical Mechanic's
  Journal; 293。
  。。。'
  His remarkable predilection in favour of the use of hydraulic
  arrangements is displayed in his specification of the surface…planing
  machinery; which includes a method of running pivots entirely on a
  fluid; and raising and depressing them at pleasure by means of a
  small forcing…pump and stop…cock;though we are not aware that any
  practical use has ever been made of this part of the invention。
  Bramah's inventive genius displayed itself alike in small things as
  in greatin a tap wherewith to draw a glass of beer; and in a
  hydraulic machine capable of tearing up a tree by the roots。  His
  powers of contrivance seemed inexhaustible; and were exercised on the
  most various subjects。  When any difficulty occurred which mechanical
  ingenuity was calculated to remove; recourse was usually had to
  Bramah; and he was rarely found at a loss for a contrivance to
  overcome it。  Thus; when applied to by the Bank of England in 1806; to
  construct a machine for more accurately and expeditiously printing
  the numbers and date lines on Bank notes; he at once proceeded to
  invent the requisite model; which he completed in the course of a
  month。  He subsequently brought it to great perfection the figures in
  numerical succession being changed by the action of the machine
  itself;and it still continues in regular use。  Its employment in the
  Bank of England alone saved the labour of a hundred clerks; but its
  chief value consisted in its greater accuracy; the perfect legibility
  of the figures printed by it; and the greatly improved check which it
  afforded。
  We next find him occupying himself with inventions connected with the
  manufacture of pens and paper。  His little pen…making machine for
  readily making quill pens long continued in use; until driven out by
  the invention of the steel pen; but his patent for making paper by
  machinery; though ingenious; like everything he did; does not seem to
  have been adopted; the inventions of Fourdrinier and Donkin in this
  direction having shortly superseded all others。  Among his other minor
  inventions may be mentioned his improved method of constructing and
  sledging carriage…wheels; and his improved method of laying
  water…pipes。  In his specification of the last…mentioned invention; he
  included the application of water…power to the driving of machinery
  of every description; and for hoisting and lowering goods in docks
  and warehouses;since carried out in practice; though in a different
  manner; by Sir William Armstrong。*
  'footnote。。。
  In this; as in other methods of employing power; the moderns had been
  anticipated by the ancients; and though hydraulic machinery is a
  comparatively recent invention in England; it had long been in use
  abroad。  Thus we find in Dr。 Bright's Travels in Lower Hungary a full
  description of the powerful hydraulic machinery invented by M。 Holl;
  Chief Engineer of the Imperial Mines; which had been in use since the
  year 1749; in pumping water from a depth of 1800 feet; from the
  silver and gold mines of Schemnitz and Kremnitz。  A head of water was
  collected by forming a reservoir along the mountain side; from which
  it was conducted through water…tight cast…iron pipes erected
  perpendicularly in the mine…shaft。  About forty…five fathoms down; the
  water descending through the pipe was forced by the weight of the
  column above it into the bottom of a perpendicular cylinder; in which
  it raised a water…tight piston。  When forced up to a given point a
  self…acting stop…cock shut off the pressure of the descending column;
  while a self…acting valve enabled the water contained in the cylinder
  to be discharged; on which the piston again descended; and the
  process was repeated like the successive strokes of a steam…engine。
  Pump…rods were attached to this hydraulic apparatus; which were
  carried to the bottom of the shaft; and each worked a pump at
  different levels; raising the water stage by stage to the level of
  the main adit。  The pumps of these three several stages each raised
  1790 cubic feet of water from a depth of 600 feet in the hour。  The
  regular working of the machinery was aided by the employment of a
  balance…beam connected by a chain with the head of the large piston
  and pump…rods; and the whole of these powerful machines by means of
  three of which as much as 789;840 gallons of water were pumped out of
  the mines every 24 hours  were set in operation and regulated
  merely by the turning of a stopcock。  It will be observed that the
  arrangement thus briefly described was equally applicable to the
  working of machinery of all kinds; cranes; &c。; as well as pumps; and
  it will be noted that; notwithstanding the ingenuity of Bramah;
  Armstrong; and other eminent English mechanics; the Austrian engineer
  Holl was thus decidedly beforehand with them in the practical
  application of the principles of hydrostatics。
  。。。'
  In this; as in many other matters; Bramah shot ahead of the
  mechanical necessities of his time; and hence many of his patents (of
  which he held at one time more than twenty) proved altogether
  profitless。  His last patent; taken out in 1814; was for the
  application of Roman cement to timber for the purpose of preventing
  dry rot。
  Besides his various mechanical pursuits; Bramah also followed to a
  certain extent the profession of a civil engineer; though his more
  urgent engagements rendered it necessary for him to refuse many
  advantageous offers of employment in this line。  He was; however; led
  to carry out the new water…works at Norwich; between the years l790
  and l793; in consequence of his having been called upon to give
  evidence in a dispute between the corporation of that city and the
  lessees; in the course of which he propounded plans which; it was
  alleged; could not be carried out。  To prove that they could be
  carried out; and that his evidence was correct; he undertook the new
  works; and executed them with complete success; besides demonstrating
  in a spirited publication elicited by the controversy; the
  insufficiency and incongruity of the plans which had been submitted
  by the rival engineer。
  For some time prior to his death Bramah had been employed in the
  erection of several large machines in his works at Pimlico for sawing
  stone and timber; to which he applied his hydraulic power with great
  success。  New methods of b