336 Improved Method of Constructing 
pieces L and M, is out of the extremity of a piece of what 
remains of the piece, Fig. 1, after the pallet-frame is formed, 
reduced to a proper thickness, because the end of the piece is 
of necessity a portion of the same circle as the end of the arm. 
‘In the common construction of pallets there is no method of 
opening and closing the pallets to the wheel, but by filing the 
inclined planes, or faces, of the pallets to open them, and bend- 
ing the arms to close them; to obviate this inconvenience, 
jointed pallet-frames have been adopted; but these, unless 
planned and executed with more than common care, areas de- 
fective in principle as in execution. In the construction of the 
pallets above described, the pallet-frame is not jointed, but 
made of a single piece, and there is no adjustment in the frame 
for opening and closing the pallets to the wheel; but the same 
end may be obtained, though not in the most perfect manner, by 
loosening the pieces L and M, (see Fig. 8,) by which the pallets 
are held fast in the frame, and pushing the pallets backwards 
and forwards in the groove. This, though infinitely better than 
the old method, is not easy, it being difficult in practice to re- 
move the pallets a very minute quantity ; and to open or close 
the pallets by this method, it is necessary to disengage the 
pallet-frame, and all the parts to which itis attached, from the 
frame of the clock, an inconvenience which is entirely obviated 
by the method about to be described. 
To remove this difficulty, the following mode of constructing 
the pallet-frame may be adopted. It admits of the pallet-frame 
being made jointed upon the same principle, and with equal 
accuracy ; and the opening and closing of the arms being regu- 
lated by a screw, their quantity of motion may be infinitely 
small, and determined to the greatest nicety. For this purpose 
a second piece, exactly similar to the piece represented Fig. 1, 
is required. See Fig. 9, of which Fig. 10, is a section. 
When the pallet-frame is intended to be made jointed, the 
sink E F, represented in the section Fig. 2, must be turned in 
Fig. 1, on the reverse side to the groove A B, and a similar 
sink, E F, must be turned in the piece, Fig. 9, on the same side 
as the groove. See Fig. 10. Itis requisite those sinks should 
