US1814874A - Dental chair elevator - Google Patents

Description

July 14, 1931. H. E. WEBER DENTAL CHAIR ELEVATOR 3 Sheets-Sheet 1 Filed Nov.

July 14, 1931. H E. WEBER DENTAL CHAIR ELE VATOR Filed Nov. 3, 1928 5 Sheets-Sheet 2 July 14, 1931. H. E. WEBER DENTALVCHAIR ELEVATOR Filed Nov. 5, 1928 3 Sheets-Sheet 3 W 5 W414 d Patented July 14, 1931 entrain erases earns.-

li'ZElflRY E. VI'EBER, 6F CANTON, GHEO, AfSSIG-NGR TO THE VJEBEB DENTAL IVL'ANUFACTUR- ING COIiiPANY, F CANTON, I OT-EEO, fr CORPORATION OF OHIO DENTAL CHAIR ELEVATOR Application. filed lloven'ibcr 3 1928. Serial No. 316,969.

The invention relates to elevators for raisi ng and lowering the seat and attached parts of a dental chair. I

lillrwators for this purpose as heretofore constructed have includedchain lifts and fluid dynamic jack lifts. I

It is essentialthat a dental chair elevator bemaintained constantly in the desired elevated position, without being lowered gradu ally or by jerks, due to the weight of the patient seated on the chair.

It has heretofore been found practically impossible to construct dental. chair elevators, which would not lower gradually or by jerks from any particular elevated-position, thereby necessitating frequent reelevations of the same.

Accordingly the principal objects of the present improvements include the provision of an improved dental chair, elevator adapted for positively and continuously maintaining the chair seat andattached parts at any desired position ofelevation.

Further objects of the improvements include the provision of an elevator operated solely by an, improved fluid dynamic jack, without requiring any chain lifts in conjunction therewith.

Further objects of the improvements include the provision of a simplified and more compact arrangement of the various parts of the elevator, and improvements in the detailconstructionand operation ofthe various parts. i

These and ancillary objects are attained in the present invention, a preferred embodiment of which ishereinafter set forth in detail, and is illustrated in the accompanying drawings forming part hereof, in which Figure 1 is a longitudinal sectional view of a preferred embodiment of the improved dental chair elevator hereof, ason line1'-1, Fig. 2; I j

Fig. 2, a transverse sectional view there.- of as on line 22, Fig. 1;

Fig. 3, an enlarged fragmentary sectional View as on line 3+8, Fig. '2, illustrating the improved outlet duct for the fluid dynamic jack for the elevator;

Figs, an enlar ed fr a 'tarysectional view as on line 4et, Fig. 1, illustrating the means for adjustably lockingthe chair seat at any desired position of rotation about its vertical axis;

Fig. 5, an enlarged fragmentary view similar to Fig. 1, distant parts being removed,

and portions being broken away for more clearly illustrating the detail construction of the improved relief valve for the fluid dynamic jack, and its arrangement with respect to other partsof the elevator;

. Fig. 6, a transverse sectional view thereof as on line 66, Fig.

Fig. 7, another transverse sectional view thereof as on line 7-7, Fig. 5; and

,Fig. 8, a ragmentary sectional view of the elevator as on line 88, Fig. 2, illustrating one of the yielding stops between two of the elevatorsv sections.

Similar numerals referto similar parts throughout the several views.

The improved dental chair elevator indicatedgenerally at 10, includes a base 11 which is preferably in the form of an upwardly opening cup-shaped reservoir 12 having a. base'flange 13 extending outwardly from its lower end.

Alower tubular elevator housing section 1 f is mounted for rotation about its vertical axis in the cup reservoir. Upper and lower cylindric bearing abutments are provided at 15 and 16, respectively, between the outer surface of the lower tubular housing section 1st and the inner surface of the tubular side wall 17 of the cup reservoir 12, and thrust bearing abutment is provided at .18 between the lower end of the housing section 14 and the uppersurface of the bottom Wall 19 of the cup reservoir.

As will hereinafter be set forth in detail, the lower tubular housing section 14, encloses the operating mechanism of the elevator, and provides a supportfor all the control levers andpedals, so that the chair seat and other usual parts attached thereto, indicated fragmentarily at 20, and which are supported through parts hereinafter to be described-in relation to the stationary supporting base 11 which rests upon the floor.

Preferably vertically coaxial with the lower tubular housing section 14, an improved fluid dynamic jack indicated generally at 21 is mounted within the housing section 14 for rotation therewith.

The jack 21 includes a housing and mounting base indicated generally at 22, and the base includes a hub 23 from which radiate preferably in opposite directions, an inlet arm 24 having formed therein and mounting the several parts of the fluid inlet means, and an outlet arm 25 having formed therein and mounting the various parts of the fluid outlet means, as will be hereinafter set forth in detail.

The hub 23 has an upwardly opening cup recess 26 formed therein, and the upper end of the cup recess is internally threaded to receive and secure the externally threaded lower end of a lower jack cylinder 27 The jack cylinder 27 and the lower housing section 14 are vertically coaxial.

A tubular lower piston 28 is slidably mounted for being raised and lowered in the lower jack cylinder 27, and is externally threaded at its upper end for carrying an in ternally threaded collar 29.

The collar 29 is externally threaded, and has screwed thereon the upper internally threaded end of a middle elevator housing section suspending tube 30, the lower end of which is setzured to a middle elevator housing section supporting bracket, indicated generally at 31.

The bracket 31 includes a central hub 32 from which radiate a plurality of supporting arms 33 upon the outer end of each of which is supported a. lug 34 extending inwardly from a. middle elevator tubular housing section 35.

The upper end of the lower elevator housing section 14 is preferably provided with an inwardly extending flange 36 through which the middle elevator housing section is raised and lowered. V v

Radial movement with respect to each other of the middle and lower housing sections 35 and 14 is prevented by providing one 'or more vertically extending guide slots 37 in the one, in each of which slots is arranged to vertically slide a guide key 38 extending from the other.

The inner surface of the tubular lower. piston 28 forms a cylinder in which is arranged to be slidably raised and lowered by the operation of the jack, an upper piston 39, of improved construction and arrangement as will be hereinafter set forth in detail, and which mounts at its upper end an upwardly extending upper elevator housing section supporting strut 40, upon the upper end of which is carried a seat and upper elevator housing mounting disk 41, the seat 20 being provide-d with a suitable recess for fitting upon the upper surface of the disk 41, and the disk 41 being preferably provided with a downwardly extending tubular flange 42,

which is externally threaded, and which is screwed in the internally threaded end of an upper elevator housing section 43.

The upper end of the middle housing section 35 is provided with an inwardly directed peripheral flange 44, through which the upper housing section 43 is raised and lowered.

Radial movement of the middle and upper housing sections with respect to each other is prevented by providing one or more vertically extending guide slots 45 in the one, in each of which slots a guide key 46 extending from the other, is arranged to vertically slide.

Yielding stop means for limiting the upward and downward movement of the middle housing section 35 with respect to the lower housing section 14, is provided by one or more rods 47 each vertically slidable in an aperture in a lug 48 extending outwardly from the middle housing section 35, and each rod 47 extends above and below the upper and lower surfaces of the lug, and there are preferably removable upper and lower screw heads 49a and 49?), respectively, on the upper and lower ends of each rod, and a compression spring 50 is interposed between each screw head and the opposite lug surface.

' The upper head 49a: of each rod 47 yield ingly impinges against the inwardly directed 1 flange '36 of the lower housing section 14, for yieldingly limiting the upward movement of the middle housing section.

The lower head 49?) yieldingly impinges against a stop pin 51 extending inwardly from the inner surface of the lower housing section 14, for yieldingly limiting the downward movement of the middle housing section 35.

Similarly, yielding stop means for limiting the upward and downward movement of the upper housing section 43 with respect to the middle housing section 35, is provided by one or more rods 52 each vertically slidable in an aperture in a lug 53 extending outwardly from the upper housing section 43, and each rod 52 extends above and below the upper and lower surfaces of the lug, and there are preferably removable upper and lower screw heads 54a and 54?), respectively, on the upper and lower ends of each rod, and a compression spring 55 is interposed between each screw head and the opposite lug surface.

The upper head 54a of each rod 52 yieldingly impinges against the inwardly directed flange 44 of the middle housing section 35, for yieldingly limiting the upward movement of the upper housing section'43.

The lower head 54?) yieldingly impinges 'pei'isating connection between t outer upper end curvedfor fi \vardly opening pivot notch (.39 formed in the outer end of the pump rank 60.

a pump cylinder is mounted, and pump piston 58 is arranged to be reciprocated in the pump cylinder 57 by oscillation of a pump actuating crank 60 pi'votally mounts-t on a horizontal stub shaft (31 which is secured in a 'bracket62 extending outwardly from the lower housing section The crank 80. extends from theshaft 61 through an aperture 83 into the interior of the lower housing section i l, and on the outside of the housing section 14 and connected with the crank 60, an elevating pedal lever lug aperture in a piston rod bearing lug 66 ez rtending inwardly from the tubular wall of tnolower housing section, and a comie pump actu- 0 1 r, v. ing tldllri 60 and t is pump piston -.od 60 is provided by stub link 8? pivotally Secured atone end by a pivot pin (38 to the piston rod The stub l i.,.k extends upwardly from the pivot pin 68 and has its in a down- T-he upper end of the piston rod has screwed thereon a sleeve 70 upon the upper end of which is provided a shoulder 71, and

cylinder.

a compression spring-"72m interposed between the lower face of the shoulder 71 and the upper face of the lug 86, thereby normally urging the piston rod and attached piston ugnvardly, ()he or more compression springs P I (8 may be interposed between theupper face If the actuating crank 60 and the-lower face 4 1., L i 1. Q

of the lug 68 for absorbing slicers of the upward movements of the crank 60.

.An inlet duct T5 proviclcs a communication between the cupreservoir l2 and the "interior of the pump cylinder 57.

A check valve '76 is provided in the inlet duct and permits oil or other fluid medium to pass from the reservoir into the pump cylinder but prevents reverse movement there-' from, and the action of the spring '4'" 2 as aforecylinder '27 by a communicating duct 7? formedin the i t arm 24,'and check valve '78 is provided in the communicating duct 77 and permits the passage of fiuid from the pump cylinder-to the jack cylinder, but pre vents reverse movementthereof.

Atthe lower endof the tubular lower piss ton 28, a plston plug 79 is secured, and has formed therein an aperture 80 of relatively small diameter which provides a communicat1on between the interior of the 1ack cylinder 21 and the interior of the tubular lower piston 28. i i i As aforesaid an upper piston 39 is slid-ably mounted in the tubular lower, piston 28, and

mounts at its upper end, as will now be set' forth in detail, the upper supporting strut 40.

in the mounting for the supporting strut 40 is embodied an improved relief valve 81 for the ack. I v r The upper piston 39 has formed therein an upwardly opening elongated cylindric socket 82, and the lower end 83 of the strut 10 is re duced in diameter, and between the end portion 83 of reduced diameter and the main body portion, an outwardly extending shoulder 84 is formed on the strut.

he reduced end 83 of the strut 40 extends into the upwardly opening cup socket 82,

'housing section and the shoulder 8 L on the strut 4:0 is seated slide upwardly and downwardly in the bore Above the upper extremity of the stem 87 one or more laterally extending apertures 88 in the strut 40 provide outlets from the bore 86, so that any fluid which may be trapped bet *een the extremity of the stem 8'7 and the inner end of the bore, may escape through the outlets 88.

' Longitudinally extending outlet grooves '89 are provided in the outer surface of the strut end 88 and extend upwardly into the main body of the strut for forming with the inner surface of the socket 82, outlet passages for fluid which 1s introduced lnto the relief valve chamber 90, which is formed by the inner tubular surface of-thesocket, the upper surface of the-socket bottom wall 91, and the lower annular eX'tr mity of the strut end '83. The valve stem 87 extends from the strut end 83 towards the socket bottom wall 91,

and'a shoulder 92 is formed thereon adjacent the lower end thereof.

Below theshoulder 92, the stem 87 is provided with an enlarged sliding cylindric seat.

93 for a'sleeve 94 which is preferably pro'vid-- ed with hexagonal outer surfaces which form fluid passageways 95 between the outer plane surfaces thereof and the inner tubular surface ofthe socket 82.

A valve closure plug 96 preferably of fibre,

leather, or the like, is fitted in-the lowerend of the sleeve 94: between the lower circular extremity of e cylindric seat 93 and the upper surface ofthe socket bottom w ll g Closure P e 6, he "seat ea, and thaslmg 94 slidable over the continuing cylindric surfaces of the seat 93 and the plug 96, provide automatic means for taking up wear on the lower circular end of the plug.

A compression relief valve spring 97 is interposed between the annular extremity of the strut end 83 and the opposite end of the shoulder 92, whereby the closure plug 96 is normally urged towards the upper surface of the socket bottom wall 91, for normally closing communication between the valve chamber 90, and a tubular aperture 98 formed in the bottom wall 91.

The aperture 98 provides a communication between the chamber 90, through an orifice 99 of relatively small diameter, with the interior of the tubular lower piston 28, when the valve stem 87 is raised by upward fluid pressure which exceeds the downward pressure of the spring 97 reacting against the strut end 83.

The strength of the spring 97 is such as will prevent the relief valve from operating as aforesaid until the jack has been extended upwardly to its full height.

After the ack has been extended upwardly to its full height the valve stem 87 is raised by continued fluid pressure, permitting all the air and excess fluid to be exuausted from the interior of the jack cylinder 21 and the interior of the tubular piston 28.

In the jack outlet arm 25, is formed an improved outlet duct 100, which includes an upwardly directed inner portion 100a communicating at 1007), at a substantial level above the lower end 1000 of the inner duct portion 100a, with a downwardly extending outer portionlOOd.

The lower end 1000 of the inner duct portion 100a communicates with a radially ex tending communicating duct 101, the inner end of which communicates with the interior of the ack cylinder 21.

A removable apertured valve seat 102 is preferably provided in the duct 101 for cooperation with a self-centering conical head 103 on a valve stem 104, the head 103 being adapted for opening and closing a passage way between the outlet duct 100 and the interior of the jack cylinder21 by rotations in opposite directions of a valve screw 105 to which the stem 104 is secured, the valve screw 105 being mounted in an internally threaded extension of the duct 101.

A pinion 106 is secured to the screw 105 for rotating the same, and the pinion 106 is meshed with an upwardly extending rack 107, which is carried atthe lower end of a rack mounting rod 108, which extends upwardly through a suitable bearing aperture in a rack rod bearing lug 109 which extends inwardly from the tubular wall of the lower housing section, and the rack rod 109 is normally urged downwardly by a compression spring 110 interposed between a shoulder 111 at the upper end of the rack rod 109 and an adjustable screw plug 112 which is screwed. in an internally threaded aperture 113 in the upper end of the lower housing section 14.

The screw 105 has threads of such inclination that when the rack rod 108 is pressed downwardly, the self-centering valve head 103 will be advanced into its seat 102, clos ing the passageway between the interior of the pump cylinder 21 and the angled outlet duct 100.

For lowering the jack, a lowering pedal lever 114 is pivotally mounted 'on a pin 115 secured in the lower housing section 14, and an inner valve opening crank 116 secured to the pedal lever 114 extends through an aperture 117 into the interior of the housing section 14, where the upper face of the valve opening crank 116 abuts against a pin 118 laterally extending from the rack rod 108.

For adjustably locking the chair seat at any desired position of rotation about its vertical axis, an eccentric 119 is secured at the lower end of a vertically extending countershaft 120 which is journalled within the housing section 14, and which is connected at its upper end with a clamping lever 121 which extends outwardly through an aperture in the housing section 14. The eccentric 119 preferably is rotatable by the clamping lever 121 in opposite directions to clamp or release flexible strip 122 against an inner cylindric clamping surface 123 formed on the interior tubular portion of the tubular side wall 17 of the cup reservoir 12.

In operating the improved dental chair elevator, constructed and arranged as aforesaid, fluid, preferably oil, is placed in the cup reservoir 12, preferably so that it fills the same to the level of the line A-A.

Oscillation of the elevating pedal lever 64 will then pump the fluid first into the interior of the jack cylinder 27 where it will immediately elevate the lower piston 28, until the middle housing section 35 has been raised to its extreme height. 1

The fluid will then be forced through the aperture into the interior of the tubular lower piston 28, where the upper piston 39 will be elevated until the upper housing section 43 has been raised to its extreme height.

Further oscillations of the pedal lever 64 will only operate the relief valve closure plug 96, as aforesaid, to pass the excess fluid out through the passageways formed bythe outlet grooves 89 of the strut end 83 and the inner surfaces of the socket 82, from which passageways the excess fluid will drop back into the cup reservoir. 7

Obviously any entrapped air will also be exhausted from the several cylinders.

The chair seat 20 is positively maintained at its extreme height, or any intermediate position, if the oscillations of the pedal lever 64 are stopped before the jack has been ele vated to its extreme height.

In order to lower the chair seat 20 all that is necessary is to push down on the lowering pedal lever 11 i whereby the seltcentering valve head 103 will be withdrawn from its seat 102, whereby the fluid will pass out from the several cylinders through the communieating duct 101 andinto he angled outlet duct 100 from which it will re-enter the cup reservoir 12.

By forming the outlet duct 100 with the upper end of the inner portion 10004, at a substantial level above the lower end thereof, and the communicating duct 101, fluid is always maintained within the lower cylinder 27 to the level of the upper end of the duct portion 100a, and as aforesaid the pump cylinder 57 is always chargedwith fluid, whereby the ack will immediately start to elevate with the first downward pressure or": the pedal lever 64:.

The chair seat 20, aforesaid, may be maintained at any desired position of rota- 1 tion about its vertical axis by operation oi upper tubular portion forming a relief chamber therein, a. load carrying strut having a lower tubular portion supported within the tubular portion of the piston, an outlet pas sageway communicating between the chamher and fluid introducing means, the bottom wall of the piston having an inlet aperture formed therein, a closure member slidably mounted in the lower tubular portion of the strut for movement towardsand from closing position across the inlet aperture, and i yielding means normally maintaining the closure member in closing position.

2. A jack for a dental chair elevator and the like, including a cylinder, a load sup porting and lifting piston operatively mounted in the cylinder and adapted to be elevated by the introduction of fluid into the cylinder, means for introducing fluid into the cylinder, and the piston having a bottom wall and an upper tubular portion forming a relief valve chamber therein, a load carrying strut having a lower tubular portion supported within the tubular portion or" the piston and forming a passageway located be tween the piston andthe strut and communicating between the valve chamber and the fluid introducing means, the bottom wall of the piston having an inlet aperture formed therein, a closure member provided with a shoulder portion and slidably mounted in the lower tubular portion of the strut for movement toward and from closing position across the inlet aperture, and spring means interposed between the shoulder portion of the closure member and the strut for normally maintaining the closure member in closing position.

A jack for a dental chair elevator and the like, including a cylinder, a load supporting and lifting piston operatively mounted in the cylinder and adapted to be elevated by the introduction of fluid into the cylinder, means for introducing fluid into the cylinder, and the piston having a bottom wall and an up per tubular portion forming a relief valve chamber therein, a load carrying strut having at its lower portion tubular walls forming an inner chamber and supported within the tubular portion of the piston, the tubular walls of the strut forming a passage-way located between tne piston and the strut and communicating between he valve chamber and the fluid introducing means, the tubular walls of the strut being provided with apertures communicating between the strut inner chamber and the fluid introducing means, the bottom wall of the pi ton having an inlet aperture formed therein, a closure member provided with a shoulder portion and slidably mounted in the inner chamber of the strut for movement toward and from closing position across the inlet aperture, and spring means interposed between the shoulder portion of the closure member and the strut for normally maintaining the closure member in closing position.

In testimony that 1 claim the above, I have hereunto subscribed my name.

nnnnr E. WEBER.

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