718 The Trials of Self -binding Harvesters at Chester. 
up the backlash. The tripper is raised by the pressure of the 
sheaf, when complete, on either of two pieces of board which 
project a little above the surface of the binder platform, and is 
kept in the tripped position during the process of binding by 
an arm mounted on to its spindle, the outer end of which carries 
a roller which rests on a cam formed on the boss by which the 
needle is secured to its shaft. 
The binding arrangements are generally of the usual kind, 
and comprise the Appleby knotter bill, and a string retainer of 
novel type. 
The Appleby knotter bill, which is now so familiar, 1 consists 
of an arrangement like a bird held head downwards, the body 
being capable of intermittent revolution on its long axis, while 
the upper mandible of the beak, speaking of the bird in the 
upside-down position, is caused to open and close as the body 
revolves by the action of a cam on a small roller attached to 
the tail end of the mandible, which is produced backwards 
through the body, and curved up into almost a vertical position. 
At each tying the body makes a complete revolution. The 
strings from the retainer and from the new sheaf, round which 
the needle has just passed it, lie side by side over the upper 
mandible ; the body turns, and by the time that it has accom- 
plished about three-quarters of a revolution the double strings 
have passed round the mandibles, and are just facing the point 
of the beak when the upper mandible rises, the strings pass into 
the open beak by the further revolution of the body ; the beak 
then closes and nips the ^strings tightly, and then the loop 
formed by them round the mandibles is pushed off the beak as 
well as over the portion of the strings retained between the 
mandibles, and, being drawn tight, forms a secure knot. The 
two strings on the retainer side of the knot are then cut by a 
knife which is advanced by a cam motion for the purpose, and 
the sheaf is ready to be ejected, while the free end of the string 
is again held by the retainer, and the string itself is, by the 
retreat of the needle, carried back below the platform, ready for 
the new sheaf. 
The retainer consists of a pair of horizontal superimposed 
gripper discs, the upper one revolving one-third of a turn at 
the formation of every sheaf. The upper disc has three round 
edged notches or recesses formed on its periphery ; into one of 
these the string on the needle falls, and is carried round till it 
jams between the two discs, which for this purpose are kept 
1 For an illustrated description of the “ Appleby ” Knotter, see Mr. Cole- 
man’s report on the Derby trials of 1881. (Journal, Vol. XVIII. p. 269.) 
