﻿[71] 
  PATENTS 
  ISSUED 
  RELATING 
  TO 
  FISH 
  AND 
  FISHERIES. 
  i045 
  

  

  chamber 
  or 
  float 
  attached 
  to 
  the 
  top 
  of 
  the 
  frame 
  serves 
  to 
  prevent 
  the 
  

   dredge 
  from 
  sinking 
  too 
  rapidly 
  when 
  lowered. 
  The 
  derrick-arm 
  is 
  

   hinged 
  to 
  the 
  carriage, 
  is 
  provided 
  at 
  its 
  outer 
  end 
  with 
  pulleys, 
  over 
  

   which 
  the 
  ropes 
  pass, 
  and 
  is 
  held 
  at 
  the 
  proper 
  angle 
  from 
  the 
  carriage 
  

   by 
  tie-rods 
  that 
  reach 
  from 
  its 
  outer 
  end 
  back 
  to 
  the 
  carriage. 
  The 
  

   carriage 
  runs 
  upon 
  rails, 
  secured 
  upon 
  and 
  forming 
  a 
  track 
  upon 
  the 
  

   deck 
  of 
  the 
  scow, 
  and 
  is 
  provided 
  with 
  winding 
  drums, 
  over 
  which 
  the 
  

   ropes 
  pass, 
  and 
  also 
  with 
  a 
  drum, 
  over 
  which 
  the 
  brush-operating 
  rope 
  

   passes. 
  In 
  operation, 
  to 
  lower 
  the 
  machine 
  into 
  the 
  water, 
  the 
  drum 
  

   (/' 
  will 
  be 
  turned 
  to 
  give 
  the 
  ropes 
  i 
  i 
  perfect 
  slack, 
  which 
  will 
  throw 
  

   the 
  weight 
  of 
  the 
  machine 
  upon 
  the 
  ropes 
  jj 
  and 
  permit 
  the 
  grappling- 
  

   arms 
  e 
  e 
  to 
  drop 
  to 
  vertical 
  position 
  by 
  the 
  downward 
  movement 
  caused 
  

   by 
  the 
  weight 
  of 
  the 
  bail 
  g. 
  The 
  machine 
  is 
  then 
  lowered 
  to 
  the 
  bottom 
  

   by 
  letting 
  back 
  the 
  drum 
  W. 
  Having 
  reached 
  the 
  bottom, 
  the 
  weight 
  of 
  

   the 
  machine 
  will 
  cause 
  the 
  arms 
  c 
  to 
  penetrate 
  the 
  mud 
  until 
  the 
  foot- 
  

   pieces 
  b 
  b 
  rest 
  upon 
  the 
  bottom. 
  The 
  drum 
  <j' 
  is 
  then 
  turned 
  to 
  wind 
  

   up 
  the 
  ropes 
  i 
  /, 
  which 
  will 
  bring 
  the 
  grappling-arms 
  ectoa 
  horizontal 
  

   position, 
  gathering 
  upon 
  them 
  all 
  of 
  the 
  oysters 
  in 
  their 
  reach 
  ; 
  and 
  the 
  

   turning 
  of 
  this 
  drum 
  g' 
  is 
  continued 
  until 
  the 
  machine 
  reaches 
  the 
  sur- 
  

   face 
  of 
  the 
  water, 
  at 
  which 
  point 
  the 
  turning 
  will 
  cease, 
  aad 
  the 
  brush 
  

   Jc 
  will 
  be 
  operated 
  for 
  cleaning 
  the 
  oysters 
  by 
  turning 
  backward 
  and 
  

   forward 
  the 
  drum 
  j. 
  This 
  having 
  been 
  done, 
  the 
  machine 
  is 
  still 
  fur- 
  

   ther 
  elevated 
  by 
  turning 
  the 
  drum 
  g' 
  until 
  a 
  sufficient 
  height 
  has 
  been 
  

   reached 
  to 
  clear 
  the 
  side 
  of 
  the 
  small 
  boat 
  IV. 
  The 
  carriage 
  is 
  then 
  

   run 
  back 
  upon 
  its 
  track 
  to 
  bring 
  the 
  machine 
  over 
  the 
  boat 
  B'. 
  The 
  

   drum 
  A' 
  is 
  then 
  turned 
  to 
  throw 
  the 
  weight 
  of 
  the 
  machine 
  upon 
  the 
  

   ropes 
  jj, 
  whereupon 
  the 
  drum 
  <f 
  is 
  set 
  free 
  for 
  dumping 
  the 
  oysters 
  

   into 
  the 
  small 
  boat. 
  Finally, 
  the 
  carriage 
  being 
  moved 
  forward 
  to 
  the 
  

   edge 
  of 
  the 
  boat 
  B, 
  and 
  the 
  boat 
  B 
  moved 
  forward 
  or 
  backward 
  the 
  

   length 
  of 
  the 
  dredging-machine, 
  the 
  operation 
  may 
  be 
  repeated. 
  In- 
  

   stead 
  of 
  using 
  the 
  drum 
  h' 
  ', 
  a 
  cleat 
  may 
  be 
  attached 
  to 
  the 
  carriage 
  C, 
  

   over 
  which 
  the 
  ropes 
  jj 
  will 
  be 
  passed 
  by 
  hand, 
  the 
  rope 
  being 
  let 
  off 
  

   from 
  the 
  cleat 
  gradually, 
  for 
  lowering 
  the 
  machine; 
  and 
  instead 
  of 
  

   placing 
  the 
  carriage 
  C 
  upon 
  a 
  track 
  crosswise 
  of 
  the 
  boat 
  B 
  it 
  may 
  be 
  

   placed 
  on 
  a 
  track 
  running 
  lengthwise 
  of 
  the 
  boat, 
  so 
  that 
  the 
  carriage, 
  

   instead 
  of 
  the 
  boat, 
  may 
  be 
  moved 
  the 
  length 
  of 
  the 
  dredge 
  at 
  each 
  

   grappling. 
  In 
  this 
  case 
  movable 
  blocks 
  are 
  used 
  at 
  the 
  outer 
  end 
  of 
  

   the 
  derrick-arm 
  for 
  bringing 
  the 
  dredge 
  over 
  the 
  boat 
  B' 
  for 
  dumping. 
  

  

  CLAIMS. 
  

  

  "1. 
  In 
  an 
  oyster-dredge, 
  the 
  frame 
  a, 
  having 
  the 
  foot-pieces 
  b, 
  and 
  the 
  

   grappling 
  shafts 
  d, 
  having 
  the 
  arms 
  or 
  teeth 
  c, 
  and 
  operating 
  mechan- 
  

   ism 
  for 
  the 
  said 
  shafts, 
  substantially 
  as 
  and 
  for 
  the 
  purposes 
  set 
  forth. 
  

  

  "2. 
  The 
  combination, 
  with 
  the 
  grappling-shafts 
  (1 
  and 
  teeth 
  c, 
  of 
  the 
  

   brush 
  /,-, 
  arranged 
  above 
  the 
  teeth, 
  substantially 
  as 
  and 
  for 
  the 
  pur- 
  

   poses 
  described. 
  

  

  