Improvements in or connected with Dental Chairs.
Year: 1893

page_text: געם VVM
Improvements in or connected with Dental Chairs.
A communication by DEWELL STUCK, of Rochester, in the County of Monroe
and State of New York, United States of America, Manufacturer.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Man-
chester, both in the County of Lancaster and 323 High Holborn, in the County of
Middlesex, Civil Engineer 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 is best described by aid of the accompanying drawings in
which :-
Fig. 1 is a side elevation of the chair;
Fig. 2 is a partial central vertical section;
Fig. 3 is a partial section on line 3-3 of Figure 4 ;
Fig. 4 is a plan of the seat frame and locking mechanism;
Fig. 5 is a vertical central section of the head rest support;
Fig. 6 is a section on line 6-6 of Figure 5;
Fig. 7 is a section on line 7-7 of same figure;
Fig. 8 is a section on line 8-8 of Figure 5;
Fig. 9 is a section on line 9-9 of Figure 2;
Fig. 10 is a section on line 10-10 of Figure 1 ;
Fig. 11 is a section on line 11-11 of same figure;
Fig. 12 is a plan of the main foot rest; and
Fig. 13 is a plan of a supplementary foot rest;
Fig. 14 is a section on line 14-14 of Figure 1;
Fig. 15 is a plan of the part of the seat frame upon which the arm rest is
supported.
6 is
Numeral denotes the base or floor plate and 2 the standard of the chair.
This standard preferably in horizontal section is closed at the bottom. It has
an open front and top and is rearwardly extended at its upper part, the whole
being arranged and constructed to adapt it to receive elevating mechanism to be
hereinafter described. 3 denotes a supporting rib formed on the base and upon
which the standard rests. 4 indicates a plug having a flanged head fitted or
seated in the base as represented and provided with an angular body 5 passing
through the bottom of the standard 2, and with a screw threaded portion 41.
a clamping nut engaging said screw to which nut is secured, by fastening screws, a
lever 7. The standard can be clamped to the base by suitably turning the nut down
upon the screw. 8 denotes a fluid reservoir, 9 a pump of which 10 is the
piston and 11 the piston lever. This has a fulcrum 12 in the studs or brackets 13
fixed on the reservoir. Under its inner or short arm is a spring adapted to
draw it down after it has been raised by the forcing down of the power arm.
lever is loosely connected with the piston by a rod or bar 14 having pivots 15.
23 denotes the piston cylinder and 17 is an opening in the top of the reservoir to permit
fluid overflow to return to the reservoir. The inlet and check valves are respectively
denoted by 18 and 19 and their closing springs by 20 and 21. Removable plugs
are indicated by 22. 23 is the main cylinder and 24 its piston loosely connected by
a supporting rod 24¹ with lever 25 and by the medium of link 26 with lever 27,
said levers having fulcrums supported in the standard at 28 and 29 respectively.
30 is a valve having its seat in the diaphragm 31. Its stem has a screw threaded
connection with plug 32. 33 is a valve-operating handle and 34 a handle-retaining
nut.
This

page_text: .
To elevate the seat support, the pump is operated in a well known manner, the
valve 30 being securely closed. Liquid such as oil, glycerine or the like is drawn
from the reservoir and forced under piston 24. The pumping being suspended
when the seat has been raised to the desired height, the valve 19 is simultaneously.
closed by its spring and the seat is held at a fixed elevation.
To lower the seat the valve 30 is opened and the liquid permitted to flow from
the cylinder 23 into the surrounding reservoir.
The chair seat frame denoted by 23 is supported upon the standard and upon
piston 24 by means of the pivoted rod 24' and the two wide levers 25 and 27 have
fulcrums 28 and 29 in the standard and are pivotally connected at their euds
opposite said fulcrums to a broad bar or lever 39, which latter has journals 40
turning in bearings on a horizontal flange of the seat frame and strongly secured
thereto. By forcing up the piston said levers are turned upon their fulcrums and
the bar or lever 39 with the seat frame supported thereon is elevated. True vertical
movement largely multiplied is secured by the parallel levers connected as described
and a large range of vertical adjustment is secured. The seat is locked in any
desired position with reference to a horizontal flange by means of the pawl 42
adapted to engage a rack 43 situated near the junction of the seat and foot rest
frames. The pawl has a fulcrum 44 in the seat elevating bar and a treadle
arm 45. 46 is a spring normally holding said pawl in engagement with the rack.
A foot rest platform is denoted by 47 and a foot rest roll frame by 48.
frame has in each of its end walls a slot or groove 49 having a notch or pocket 50.
Lugs adapted to fit and be moved in said grooves are denoted by 51, and foot rests
or foot rest rolls by 52. This frame and the rests are adapted to be adjusted by
sliding upon the lugs and they are locked in their extreme position by the lug
dropping into the notch 50. A similar rest for children is indicated by 53, the
foot rest platform support being cut away at 54 (shown in Figure 3) to receive the
supporting arms of said foot rest when it is pushed inwardly as indicated by
dotted lines.
This
The head rest 55, shown in Figures 1 and 5, is supported from the seat frame 35
by pivots 57 connecting the brackets 58 of said frame with the lugs 59 of a
swinging back frame 56, U-shaped in cross section as shown in Figures 7 and 8.
60 is a brace or supporting bar pivoted to the seat frame and adapted to be
clamped to the back frame by means of a screw 61 and a nut 62 having a
handle 63. The back frame is made vertically movable on the screw 61 and
brace 60 by means of the slot 64 and 65 in the frame. 66 denotes a slide or inner
back frame similar in cross section to the main or outer frame 56. It is provided
with ribs 65 adapted to run in grooves in the said back frame. It is held in any
desired elevation by the set screws 68. 69 is a sliding bar, the edges of which fit
and are adapted to move in grooves 70 formed in the slide 66. 71 is a rod
vertically movable in a passage in said bar. 72 denotes a friction pawl pivoted in
a slot in the bar 69. One end extends into a recess in the rod 71 and the other is
adapted to bear on the interior of the slide 66. The bar 69 passes through an
opening in the end of a lever 73 having a fulcrum at 74 within a lever 75 having
the form of a shield or cover. The slide 69 also extends to or into an opening in said
shield which opening is covered by the head 76 of the rod 71. 77 is a nut provided
with a handle and fitted to the rounded screw threaded upper end of the bar 69.
The screwing of nut 77 against lever 75 moves said lever about its fulcrum and
tends to depress its opposite or right hand end, which through the action of bolt 79
pulls down the left hand end of the lever or cover 80 and raises its opposite end
with the effect of clamping the head rest. If the nut 77 be further screwed up it
will produce a relative downward movement in the bar 69, whereby the heel of
pawl 72 is thrust against the bottom of the recess in rod 71 with the effect to
throw its toe outward against the slide bar 66 and bind the bars together.
Though these movements are for the sake of clearness described as successive and
as pertaining only to levers 73 and 81 and bar 69 they are practically simultaneous
and the effect would be the same if in the operation the levers 75 and 80 and
1

page_text: rod 71 were reciprocally moved to a slight extent. To unclamp the head rest, the
nut 77 is drawn down on bar 71 whereupon the clamp is relaxed by gravity and
levers 75 and 81 tilted until the left hand end of the latter bears on the nut 77.
The clamping effect of pawl 72 is obviated or overcome by lifting the bar 69 by.
means of the handle or nut 77 whereupon the whole head rest can be dropped,
the bar 69 descending in its bearings within bar 66. To clamp the bars together
again it is only necessary to screw the nut against lever 75.
The mechanical details of the construction may be varied without departing
from the invention provided substantially the same mechanical and operative
principles are employed. Thus it is not essential in all cases that the standard be
oblong in horizontal section nor that it have an extension of the form shown to
receive the fulcrums of the elevating levers, nor that said levers be connected by a
link near the point of attachment of the piston rod. It is important that the
levers be so arranged and connected that they will give to the seat a large range of
movement in a vertical line and in respect to the head rest it is considered
material that the same device serves to raise the adjustable slide bar, lock the
same and clamp the head rest in position.
84 is a
In Figures 1 and 14 is represented a detachable and reversible arm rest 82,
provided with an extension or foot 83 fitting a socket in the seat frame.
pin also entering one or the other of the sockets 85 in the frame, which pin holds
the arm rest from turning about the extension 83. The post of the arm rest is
bent laterally as indicated in Figure 14, the effect being to widen or narrow the
setting space according to the adjustment to suit different persons, or in particular
emergencies to permit the operator to get nearer to the patient, the rest being:
inwardly inclined at such time.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent I declare that what I claim is :
1. The combination of the standard, the parallel levers having fulcrums therein,
the seat frame, the bar 39 pivoted to each of said levers and extending backwardly
and over the point of application of power to said levers and journalled in said
frame, and mechanism for moving the levers connected to the same at one end of
said fulcrums and immediately under the connection of bar 39 with the seat frame,.
consisting of a piston having a rod pivotally connected therewith and with the
levers and means for raising the piston, substantially as set forth.
2. The combination of the standard, the parallel levers having fulcrums therein,
the seat frame, the bar 39 pivoted to each of said levers and extending backwardly
and over the point of application of power to said levers and journalled in said
frame, and mechanism for moving the levers, consisting of a piston having a rod
pivotally connected therewith and with the levers and means for raising the piston;
substantially as set forth.
3. The combination of the standard, the parallel levers having fulcrums therein,
the seat frame, the bar 39 pivoted to each of said levers and journalled in said
frame, and mechanism for moving the levers about the fulcrums consisting of a
piston having a rod pivotally connected therewith and with the levers, means for
raising the piston and means adapted to automatically lower the same, substantially
as set forth.
4. In combination the seat frame, a rack fast on said frame, an elevating bar 39
loosely connected to and supporting the frame, mechanism for raising the bar
consisting of the parallel bars fulcrumed in a chair standard and the piston and
piston rod, said rod being pivotally connected both to the piston and to the levers,
and a pawl having a lever extension pivoted to and movable with said elevating
bar; whereby the chair seat can be raised and automatically lowered and also.
tilted and locked in the tilted position at any desired elevation, substantially as
set forth.
5. The standard having an open side and top and having its upper part enlarged

page_text: or laterally extended, levers having fulcrums in said extensions and extending
through the open side of the standard, the seat supported on said levers and means
for raising and lowering the latter, substantially as set forth.
6. The rotatable chair standard provided with a lateral extension near its upper
part and a vertical slot on the side opposite the extension, a seat elevating piston,
a reservoir containing the same, and situated adjacent to the standard wall below
said extension, a centrally situated clamping lever, and seat elevating levers
extending through said slot, substantially as set forth.
7. The standard having a closed bottom and circumferential walls adapted to
enclose seat elevating devices and provided with a lateral extension and with
elevating levers fulcrumed in its extension and slotted in one side for the passage
of a standard clamping handle 7 and of the elevating levers, the open-topped
reservoir situated on said bottom at one side of its centre, the pump, and the main
piston cylinders situated in the reservoir, and a valve having an operating handle
situated above the reservoir and extending through the enclosing wall of the
standard, substantially as set forth.*
8. In combination of the seat frame, the back frame slotted in its bottom and
rear and pivotally connected to said seat frame, the brace pivoted to the same
frame and having at its outer end a pivoted screw and clamping nut, said screw
being adapted to move in the rear slot of the frame when not clamped; substantially
as set forth.
9. The combination of the head rest, the lever having arms embracing a part of
said rest, a second lever crossing the first and having a seat for said part, said
levers having a common fulcrum, and overlapping the first named pair, a bolt passing
through the over-lapping arms of the four levers and engaging the interior ones,
and mechanism for forcing together the ends of the said second pair of levers
which are opposite said bolt to clamp the head rest; substantially as set forth.
10. In combination the swinging back frame 56, provided with grooves, the
sliding frame 66 fitting said grooves and itself provided with grooves, the bar 69
fitting the latter grooves, the rod situated in a passage in the bar, and a friction
pawl pivoted in the bar, and adapted to be operated by the rod to lock the slide
bar to the sliding frame, means for relatively moving the bar and rod, means for
clamping the main sliding frame to the back frame, and a head rest supported from
the bar and rod; substantially as set forth.
11. The foot roll frame having a curved groove in each end, and a foot rest or
platform frame provided with lugs fitting said grooves, the roll frame being provided
with one or more rolls and adapted to be slid on the lugs to and from the chair
seat to give various elevations of a roll, substantially as set forth.
12. A supporting roll-frame having a curved groove in each end and a foot rest
frame having lugs fitting said grooves provided with one or more rolls, the roll
frame adapted to be slid on the lugs to and from the chair seat to give various
elevations of a roll, one of said grooves communicating with notches on its under
side to receive a lug, whereby the roll frame is secured in different positions,
substantially as set forth.
Deted this 13th day of February 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.