J.W.Bartlett
Bartlett's
design was registered in the UK by M.A.F.Mennons in 1864.
The needlebar i, Fig.2, is reciprocated in a guide oscillating
about a fixed pivot, by a pin on a disc crank e at the
end of a shaft in the casing d, Fig.1. The bobbin l
is carried on a bracket attached to the needle bar, and a pin,
on the top of the latter, having a roughened surface, affects
the feed. The length of stitch is regulated by an obliquely-slotted
plate m. A single or double looper r is reciprocated
laterally by a cam-actuated rod s, and a stop t
on the looper held against the bracket arm by a spring u
causes a second reciprocation at right angles to the former
one.