Improvements in Plungers or Pistons of Syringes, Pumps, and such like Apparatus.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Plungers or Pistons of Syringes, Pumps, and such
like Apparatus.
ALFRED JOHN PURSER Trafalgar Works, Palmer Street Birmingham Brass-
founder, do hereby declare the nature of this invention to be as follows:-
My invention consists in forming the plungers or pistons of syringes pumps and
similar articles in such manner that the packing of the said plungers or pistons
may be tightened or expanded without the necessity of opening or removing any
portion of the said apparatus. I effect this by forming the plungers or pistons
with a fixed plate at its extremity and a loose screwed plate working upon the
lower end of the piston rod, between which two plates the necessary packing is
placed, the upper surface of the loose plate carries studs or projections on the
inner or under side of the cap or stuffing box through which the piston rod works,
so that by first drawing the piston or plunger up to the cap or stuffing box by
means of the handle the studs or projections engage, and by turning the handle and
piston rod, the upper loose plate of piston or plunger is forced down upon, or
raised from the expandable packing so tightening or easing as required.
The portion of the upper cap carrying the studs or projections may extend
through to its outer surface and by means of milling or wings be turned inde-
pendently of the piston rod so as to tighten or ease the upper plate of the piston
or plunger.
Dated this 18th day of February 1895.
COMPLETE SPECIFICATION.
Improvements in Plungers or Pistons of Syringes, Pumps, and such
like Apparatus.
I, ALFRED JOHN PURSER, of the Firm of G. and W. Purser, of Palmer Street,
in the City of Birmingham, Manufacturer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention consists in forming the plungers or pistons of syringes, pumps,
and similar articles in such manner that the packing of the said plungers or
pistons may be tightened or expanded without the necessity of opening or removing
any portion of the said apparatus. I effect this by forming the plunger or piston
with a fixed plate at its extremity and a loose screwed plate working upon the
lower end of piston rod, between which two plates the necessary packing is placed,
the upper surface of the loose plate carrying studs or projections which engage
with similar studs or projections on the inner or under side of the cap or stuffing
box through which the piston rod works, so that by drawing the piston or plunger
up to the cap or stuffing box by means of the handle, the studs or projections
engage, and by turning the handle the upper loose plate of plunger or piston is
CD 5777

page_text: forced down upon or raised from the expandable packing, so tightening or easing
it as required.
The portion of the upper cap carrying the studs or projections may extend
through to its outer surface, and by means of milling or wings be turned
independently of the piston rod so as to tighten or ease the upper plate of the
piston or plunger.
In the accompanying drawing Fig. 1 is a side sectional view of a pump barrel
containing my improved piston or plunger in which A represents the piston rod,
the lower extremity of which carries fixed plate B. The portion A² of rod is
screwed externally and engages with compressing nut D which carries upon its
upper surface two or more lugs or teeth D2, the lugs D2 engaging with the
corresponding lugs or teeth G¹ and G2 upon the under or inner surface of cap F.
Upon drawing up plunger to top of syringe or pump the lugs or teeth D² engage
with those of cap Fat G G2, and by turning the piston rod the compressing nut D
is raised or lowered, thus loosening or compressing the packing E. G represents
a washer between nut D and packing E to distribute pressure evenly.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A contrivance whereby the packing of the pistons or plungers of syringes or
pumps can be compressed or expanded without the said syringes or pumps being
opened or the pistons removed therefrom, substantially as hereinbefore described
and illustrated on the accompanying drawing.
Dated this 14th day of November 1895.