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Publication numberUS1656760 A
Publication typeGrant
Publication dateJan 17, 1928
Filing dateSep 25, 1923
Publication numberUS 1656760 A, US 1656760A, US-A-1656760, US1656760 A, US1656760A
InventorsA. W. Schramm
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
A cobpoba
US 1656760 A
Abstract  available in
Images(5)
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Claims  available in
Description  (OCR text may contain errors)

I Jan. 17,1928. 1,656,760

m A W. SCHRAMM CHAIR ELEVATING MECHANISM Filed Sept. 25, 1923 5 Sheets-Sheet 1 Jan. 17, 1928. v A. w. SCHRAMM CHAIR ELEVATING MECHANISM Filed Sept. 25, 1923 5 Sheets-Sheet 3 Jan. 17, 1928. 1,656,760

4 A. w. scHRAMM CHAIR ELEVATING MECHANISM Filed Septf25, 1923 5 Sheets-Sheet 4 Jail. 17, 192s.

A. w. SCHRAMM CHAIR ELEVATING MECHANISM Filed Sepi. 25, 1923 5 Sheets-Sheet s @Qumd-m Patented Jan. 17, 1928.

UNl'l'ED S'YiA'l'ES ADOLZPH W. SCHIBAMMI, O1? RIVERTGEQ, NEW JERSEY, ASSIGNOI-t TO ELECTED DENTAL,

iv'mnnrncrunine cor/renn n 'rron OF PENNSYLVANIA...

O}? PHILADELPHIA, PEEHFSYLVANIA, A GOBEOBA- CHAIRELEV ATING hIECI-IANISM.

Application filed September 25, 1923. Serial No. 664,697.

One object of this invention is to provide a novel elevating mechanism particularly adapted for dental and barber's chairs,

whereby it shall be possible to conveniently control the raising and lowering of a chair body, and the invention especially contemplates means for movingsaid body cont-in uously as opposed to intermittently acting means, in either direction for any desired distance within predetermined limits, together with means whereby the speed of movement is caused'to bethe same when the chair body is lowered as when it is raised, or it desired: made different from the latter.

A further object of the invention is to provide novel means for limiting the movement of the several parts of the device with a view to preventing damage from overtravel.

The invention also contemplates.elevating mechanism. including coaxial screws together with novel means foroperatively connecting cert-ain'oi said screws and novel means for prrmzntinp the actuating motor being reversed until ithas come to rest.

The invention'fi'irther includ s automatic satety devices whereby the reversal of the motor is prevented until it and incidentally the mechanism to which it is connected, has come to rest, together with means whereby the motor controlling switch is automatically released irom thecoutrol of the operator when the parts of the device has moved to *ithin predetermined distances of the limit oi? their safe travel in either direction.

Another object of the invention is to provide novel braking means for causing the downward speed of the chair body to be the same as its upward speed, which mechanism shall also be available :tor holding the chair body with its applied load in any given position, as well as for preventing itscoasting downwardly ;--the construction moreover being sued asto operate silently.

I also desire to provide device of the gen,- eral character above indicated with novel meanstor mounting the motor so as to maintain the alignment of the motor shaft and the member driven therefrom, which means shall be particularly adapted to permit of the motor. being conveniently removed and replaced by another.

The invention also includes a novel form oi cover particularly designed to itacilitate the inspection of the mechanism and includnovel means whereby it may be conveniently and quickly moved into a position permitting 0r such inspection. 1

The invention likewise contemplates novel automatic means for supplying and circulatlug lubricant for the elevating and guiding mechanism in order that'lwear may be reduced to aminimumh t it further desire to provide means for manually operating; the chair in event of failure oi the elevating motor to properly function or in the event of failure of the current supply. I

nese objects'and other advantageous ends I attainas hereinafter set forth, refierence being had to the which,

Fig. 1 is a plan of a chair constructed in accordance with my invention;

Figs. 2'and 3 are vertical sections taken respectively on the lines 2-2 and 3-3 of Fig. lf a part of the enclosing casing being shown in Fig. Braised to permit inspection of the elevating mechanism;

l. is a vertical section on an enlarged scale, taken on the line l4, Fig. 1;

Fig. 5 is a transverse vertical section on the line 55, Fig. 4;

Fig. tl is a vertical section also on an eng larged scale, taken. on the line 6-6, Fig. 1;

Fig. 7 is a horizontal section on the line 7-7, Fig. 6; 5 i 1 Fig. 8 is an elevation of a portion of the motor reversing switch; A

Fic'j 9 is an elevation of the cam drum forming part of my invention;

Fig. .10 is an elevation of a detail of the invention, r i

Fig. 11 is an enlarged horizontal section taken through the telescoping screws and the rollerswhereby they are splined together and,

Fig. 12 is an elevation partly in section illustrating the connection between the switch and the cont-rolling lever. In the'ahove drawings, 1 represents a base plate having a central circular opening in which is removably mounteda pan-like supporting member 2 held inplace by suitable means such as screws (not shown). lhis pan is provided with an upwardly projecting flange 3 forming or'defining an annular reaccompanying drawings ,in

cess for the reception 01" the outwardly prohas a body portion 5 and an upwardly ex tending hollow column 6 constituting a container and guideway for certain elements hereafter referred to. i

'A portion of the body of the chair is indicated at 7 and this has an inverted dished form, being fixed to and carried by the up per end of a vertically extending sleeve 8 to whose lower end is fixed an internally threaded nut 9 slidably guided within asec- 0nd sleeve 10. The upper part of this first sleeve 8 is also guided in a suitable bushirg' 11 fixed within the up er end of said second sleeve 10. The upper part of the latter is likewise guided by a second bushing 12 mounted in the upper end of the column 6, while the lower end of said sleeve 10 has fixed. to it a nut 13 which slidably engages and is guided by the inner cylindrical sur face of the column Mounted coaxially within the sleeves 8 and 10 is avertically extending screw 1 having fixed to its lower end a gear 15. The latter and the screw Ll are supported on a suitable ball bearing 16 carriedby the pan structure 2. This screw is engaged by the nut13 of the sleeve 10 so that said sleeve will move vertically up or down when the gear and its attached screw are rotated. The nut 18 supports a ball bearing 17 which in turn supports a tubular screw 18 extending through the nut 9. These two telescoping screws 14 and 18 are operatively connected so that they necessarily rotate together, while being free to move longitudinally one over the other. For this purpose I mount on the upper end of the screw 14- two pairs of coaxial rollers 19 (Fig. 11) and so form the interior of the screw 18 as to provide guideways for said rollers, which thus insure relative longitudinal movement of said screws with a minimum friction. At the same time the above construction insures that said screws are in effect keyed or splined together so that they necessarily rotate together.

The nut 13 is rigidly fixed to the sleeve 10 which is prevented from rotating in the column 6 by a longitudinally extending and preferably integral key 20, (Fig. 1) operative in a lteyway of the bushing 12 which is fixed in the upper end of the column 6. Similarly the nut 9 is fixed to the lower end of the sleeve 8 which is provided wit-ha key 21 also preferably integral with the tube and longitudinally slidable through a suit able lreyway in the bushing 11 fixed in theupper end of the sleeve 10.

Vi ith this construction and arrangement of parts, rotation of the gear 15 causes rotation of the screws 14; and 18, and rotation of the screw 14 will cause vertical movement thereon of the nut 13 and hence of the sleeve 10. This vertical movement of the nut 13 imparts a similar movement to the hollow screw 18, which being rotated with the screw is, imparts relative vertical movement to the nut 9 and sleeve 8. The latter is consequently moved vertically at a speed,

. which, if the two screws have the same pitch,

structure considerable range of movement so the no chair bodyavill be raised to a relatively great height when the parts are at their upper limit of motion.

It is especiall -x to be noted that the frame structure is ovided with a downwardly extending ige 22 coaxial with the screws 1ft and 18 a ldesigned to extend immedia ely adjacent the body of the gear 15 so as to insure that this shall not separate from or move vertically relatively to the ball. bearing 13 or its supporting structure liilre vise the on er screw 18 has on its lower end an Otl'tvf extending flange 18 whicn projects undc' a suitable annular shoulder formed on the lower portion of the sleeve 10 so as to prevent the possibility of said screw moving vertically relatively to the ball bearing 1? and the nut 13 on which it rests.

For driving the bevelled gear 15, 1 pro vide a second beve led gear 23 frictionally connected to the hu Eli of a worm gear 25 2). The l gear is rotatably supported upon a fixed spindle 26 suitably mounted in a in n of the frame structure 5 and is dri era a worm 27 on a shaft actuated meansv hereafter described,

V To lock the spin in place it is iorined with a notched head (Fig. 10) designed to be engaged by the tooth o? a dog 26, having a slot concentric with said spindle and designed for the reception of a clampingscrew 26.

For frictionally connecting the bevelled gear 23 with the n rm gear 25, I provide a ring 230 coaxial with said bevelled gear 23 'irictionallv drawn against it by a series of screws 31 extending through the hub 24: of the worm. wheel 95 parallel to the spindle Each of these screws is yieldingly acted on by a bowed spring plate 32, (Fig. 4) mounted between its head and the adjacent face of the worm wheel 25. and the-arrangeniont and proportions of the parts are such that slippage will occur between the ring 30 and the bevelled gear 23 ween more than a undetermined load is applied to the latter:the device serving as a safety mechanism to protect the whole driving train from 28,1 form on the motor casing a'pair of oppositely projecting lugs 34, and coaxially with the armature shaft 33 provide said motor with a sleeve projecting beyond a plane portion of the motor casing which lies at right angles to said armature shaft. The face of that portion of the frame 5 againstwhich the motor is to be mounted is likewise faced off, and. concentrically with the worm shaft 28' is recessed for the reception ofthe projecting end of the motor sleeve 35. with a pair of headed studs 36, so positioned as to lie respectively under the lugs 34 when theend of the sleeve 35 is entered in the recess of said frame ;-the latter having an opening vertically above the Worm shaft 28 for the reception of a bolt 37. This bolt is designed to be threaded into the upper and central portion of a clamping yoke 38, the lower ends of whose branches rest upon the lugs 34, beyond which they are forked to respectivelyfit upon the studs 36 (Fig. 4).

ith this arrangement of parts, when it is desired to operatively connect the motor with the worm shaft the sleeve35 is entered in the recess of the frame 5 so that the toothed end 33 of the armature shaft 33 meshes with oroperatively connects to the correspondingly toothed end. 28 of said worm shaft 28. The yoke 38 is then placed betweenthe body of the motor and the lugs 34 so that it extends over these and has the forked ends of its branches engaged with the studs '36, after which the" bolt 37 is tightened, thus through the yoke so acting on the lugs 34 that the plane face of the motor is brought into and maintained in intimate engagement with the adjacent plane face of the supporting frame, while the two shafts 33 and 28 are operatively coupled in alignment.

For insuring that the downward movement of the chair shall'take place at the same speed as .its upward movement and also for the purpose of bringing the motor to rest when the electric currentis out off, I provide sultable mechanism such as that shown in Figs. 4 and 5, which broadly consistsof an automatic braking device applied in the present instance to the worm shaft 28, although obviously without departing froinmy invention, itmay he applied at other-parts of the mechanism between the motor29 and the screw 14. This de vice includes in the present instance a re taining ring 39 threaded into the frame The frame 5 is also provided structure 5 coaxially with the work shaft 28 and incidentally designed to adjustably retain in position the worm 27, carried by said shaft. This ring is preferably castellated. and is adjustablyheld in any given position by a toothed plate 40, (Fig. 5) having a slot 41 for the reception of a clamping screw 42- threaded into said frame. The outer face of the ring 39 is formed with holes for the reception of a suitable number of pins 43 projecting from and in. the

present instance, integral witha disc 44.

In said holes are suitable springs 45 tendipg to force outwardly said pins and the c isc.

The outer portion of the worm shaft 28 is provided with a relatively coarse thread 46 on which are mounted a relatively fixed nut 47 and an adjustable nut 48, respec tively provided with pairs of cooperative projections or teeth 49 and 50, whereby the rotation of the nut 48 is limited relatively to the nut 47. The latter is fixed in any given position on the screw 46 by a cotter pin 51, and between said nuts I mount a suitable coil spring 52 having its ends connectedto them respectively so that it tends to turn the nut 48 on the, screw 46 in one direction and opposes its movement in the opposite direction. This second nut 48 is 4 provided with an outwardly extending flange and between the latter and the disc 44 is mounted a ring 53 of material, such as brake lining, for causing friction between these members.

lVith this arrangement of parts, when the armature of the motor 29 is turned in such a direction as to cause'elevation of the chair body, the shaft 28 and the worm 27 thereon turn in such a direction that the screw '46 tends tocause the nut 48 to back away from the disc and hence relieve the friction between the flange of said nut.

and theifixed disc 44. As a result, this braking and regulating 'Cl8VlCG Olf6I'S-p1fl(3 tically no opposition or resistance to theabove noted rotation of the shaft 28 and the consequent elevation of the chairbody. If,

however, the direction of rotation of the motor is reversed or occurs in theopposite direction, as when the chair body is tobe lowered, the shaft 28 and hence the screw 46, turn in such a direction that the nut 48 is automatically movedtoward the disc 44, owing to thecombined action of the spring 52 and to the friction existing between the face of its'flange, the friction ring 53' and the disc 44, as well as to-theinertia of the nut 48 or to the latter alone if said spring be omitted, as may be the case under certain conditions,

As a consequence of this rotation of the nut 48 and'the resultant increased friction between itsflange and the fixed disc 44, the

further relative rotation of the two nuts can and the frictional resistance to the rotation nut 48 is so far rotated on the screw46 that its pins 50 come into engagement with the pins 49 of the fixed nut47. Thereafter he occur and the continued rotation of the shaft 28 and the operation of the motor is opposed by the constant frictional force due to vthe above device. If during this operation, the current should be cut ioi'i from the motor, the trictionalresistance applied by said device serves as abralce which brings to rest the motor armature and the train of mech anism connected thereto, so that coasting or downward drifting of the chair body is eti'ectually prevented. By means of the adjustable nut 47, the amount of the braking force applied may be so regulated that the motor andits associated, parts are caused to operate at any desired speed when the chair body is moving downward, and when current is cut off from the motor will bring it to rest and thereafter hold it motionless. As soon as the downward movement of the chair body has been arrested, the above described brakingor load-regulating device is again in condition to permit either the relatively tree'upward movement of the chair body without opposition, or to exert a frictional opposition to its downward movement as above described.

For providing the necessary lubrication to the above described mechanism and also for supplying a working fluid for governing the motor controlling elements of the apparatus, l utilize a liquid such as a suitable lubricating oil and form the hub of the bevelled gear 15 with, ormount upon it, an eccentric 54 (Fig. 3) having an annular groove or channel 55 communicating through a passage .58 with an axial passage 59 in the screw 14. Mounted on the eccentric 54 is a strap 56 having an eccentric rod 57 formed with a plunger 60 operative in an oscillatory cylinder 61. s The latter is mounted tooperate on aihollow spindle 62 fixed in the. frame structure 5 and provided at its upper portion with a valve seat for the reception of a check valve 63. The hollow passage of this spindle communicates with the chamber of the cylinder 61 which has also a passage opening into the lower portion of the pan 2' and controlled by a check valve 65. The plunger 60 and cocentric rod 57 are hollow or tubular and the former has asuitable seat for the reception of a spring-controlled valve 64; the arrange ment being such that the rotation of the gear 15 reciprocates the eccentric rod and plunger 60, causing liquid to be drawn from the pan 2 into the chamber of the cylinder 61 and discharged there-from through said plunger and connecting rod into the screw 14. It is-also delivered through the spindle 62 past'the valve 63 into the chamber of a cylinder 66 formed to extend vertically in a portion of the structure 5.

The upper end of the second screw 18 is normally closed by a plug 67 having passages 68 leading outwardly from its hollow interior. Into this plug is threaded a downwardly extending tube 69 making a sliding surface of the screw 18 as well as through passages 68 so as to lubricate the threads of the screw 14. It may also enter other suitably placed passages 8 and 10 so as to provide the desired lubrication for the other parts of the telescopic elements of the chair elevating mechanism above described and from all-of these said. lubricant drains back into the panQ for repeated use. From the lowerpart of the cylinder 66 I provide a pas=age 71, (Fig. 6) whose area of cross section may be regulated and restricted to any desired extent by a screw 7 2 and whichleads to a discharge pipe 73 whose outlet is so positioned as to deliver lubricant over the worm 27 and to its associated bearings.

In order to prevent accidental overtravel oi the chair-operating mechanism in either direction and to permit of the apparatus being reversed after it has been brought to either extremity of its possible movement, as well as to prevent the possibility of reversalof the motor while its armature is still turning, I provide the mechanism shown in Figs. 2, 3, 6 and7, which is particularly distinguished by the fact that it utilizes the lubricating liquid as its governing medium.

For this purpose, the cylinder 66, (Fig. 6) has mounted within it a plunger 74 whose upper end is made conical as indicated at 74", so as to be capable of co-operating with the suitably formed portion of a switch lever 75. This latter is connected to what in the present instance is a vertically extending spindle 76, bya horizontal pivot 77 which extends through va slot in said spindle so as to be capable of axially turning it. This spindle governs or is operatively associated with motor controlling mechanism or apparatus such ascertain relatively movable contacts 78, 78, 79, 79 79 and 79, (Fig. 8) which coact with suitable fixed contacts 81-82 and 83--84 for controlling the starting, stopping and direction of rotation of the motor.

Suitable means are provided for resisting movement of the spindle 76 with its contacts from and for insuring its return to, a neutral or off position, and for this purpose I provide a device such as a disc 85 fixed to the spindle. This disc has a pair of pins 86 projec'ting from one of its :t'aces so as to co operate with the ends of the branches of a yoke 87 This is mounted on an arm 88 slidable in a suitable portion 89 of the fixed supporting structure, and acted on by a spring 90, whereby said yoke is at all times pressed toward the pins 86, thus tending to return the spindle 76 with its attached parts to a mid or neutral position.

The fixed supporting structure 89 coaxially with the spindle 76, is provided with a hub or extension 91 on which is rotatably mounted the controlling lever '92 for starting, stopping andcausing reversal of the motor, and this lever is connected by a link 120, (Fig. 1) with an arm 121 fixed to a vertical 1y extending spindle 122 (Fig. 2) whichlikewise has fixed to it a foot lever 123 projecting from the base. Said lever 92 has an arm 93 formedwith an upwardly projecting rib 94 having an upwardly opening central recess 95 (Fig. 12) designed for the reception of the switch lever 75 under certain conditions, it being noted that said rib slopes upwardly on both sides to this centrally placed recess. As shown inFig. 6, the lever 92 has a pair of upwardly projecting posts 130 designed to cooperate with the arms of a yoke 131 whose body 132 is slidably guided in an opening in the structure 89. A'spring 133 on this body at all times presses the ends-of the yoke toward the posts 130 and tends to return the lever 92 to or retain it in its neutral or mid position. The parts are so designed and arranged that when, owing to the presence of liquid under pressure in the cylinder 66, (Fig. 6) the plunger 7 4c is forced to .its upper limit of motion, it is capable of swinging the switch lever 7 5 on its pivot 7 7 to such aheight as to move it out of the recess 95 and thus operativelyuncouple it from the foot or main lever 92. Moreover,

owing to the conical form of the end 7 4 of this plunger 74:, which is so positioned as to be operative when the levers 92 and 75 are in their neutral or 0E positions, the lever 75 will ride up on this end as said two levers approach the neutral or oft position and will be disconnected from said foot lever. If, however, said plunger is in its lower position, it obviously cannot operate on the lever 75 and hence cannot then act to disconnect it from the control lever 92.

With this construction, if for example the foot controlled lever 92 be moved from its neutral position in either direction, it carries with it the switch lever 75to which it is nor mally coupled. As a consequence, current is supplied to the motor29, which thereupon vided by the plunger 60 and cylinder 61.

This latter not only supplies lubricant to the various parts ofthe apparatus but at once causes said lubricant to act upon the plunger 74, which is thereupon moved to its upper position.

It now the foot lever be released and allowed to return to its cit position, the switch lever 75 automatically disconnected from itupon reaching its neutral or off position, owing to the "fact that it rides up on the conical plunger end 74 andis swung upwardly on its pivot 77 out of the recess "95. Consequently even tliough the foot lever be again operated from its off position, the motor cannot be started in either direction until it comes torest, since it is first necessary that the pump plunger 60 cease to operate and for the liquid in the cylinder 66 to leak out through the restricted passage 71. When this has occurred, the plunger 74: falls and again permits the switch lever 7 5 to enter the recess 95 of the lever 92 so that this may be again moved by the operator. From the above it will be obvious that it is not possible for the operator to cause reversal of the motor until its armature has first come to rest.

Damage to the latter is thus eii'ectually pre vented, since it is an impossibility to supply said motor with current while its rotor is still moving under its momentum .or is being driven by the weight of the chair body and its associated parts.

In order to prevent the motor being continued in operation with a resulting injury to the apparatus after the-chair body has been moved to its allowable limit of movement in either direction, I provide on the tube 10 two projecting pins or lugs 100, (Fig. 3) positioned to operate in cam grooves 101 and 102 formed in a cam drum 103' fixed to a vertical spindle 104 suitably supported on the trame,preferably on a portion of the column 6. On the lower end of this spindle is an arm 105 which extends between the branches of a forked arm 106 (Figs. 1, 3 and 6) fixed to an oscillatory spindle 107, supported so as to extend horizontally under the switch lever'75. Fixed on said spindle is a sleeve having .two cam portions 108 and 109 shaped to cooperate with the switchlever 75 when this is in the two positions in which the nrovable contacts 78 and 79 engage the cooperating fixed contacts of the electrical controller.

When the chair body is moved by the operation of the motor toward and into its ex treme upper position for example, one of the projections 100 on the sleeve 10 entersthe cam groove 102 ionexample, which is so shaped that as *a result the cam drum 103.

and hence the spindle 104 is turned through a predetermined angle. The arm 105 is thus likewise given an angular movementas is since the second one of the projections 100' so cooperates with the cam grooves 101 to turn the spindle 101 'nto such a position that the part 108 of the cam sleeve similarly raises the switch lever 75 out of the recess of the operating lever, leaving it free to re turn to its oil position in which the apparatus is permitted to come to rest without possibility of overtravel and consequent damage.

lit is to be noted that if after the switch lever has been automatically disconnected from the operating lever at the upper limit of travel of the chair body for example, said latter lever may be again connected to said switch lever by permitting the former to move to the neutral position. The motor however, can only be started in such a direction as to cause downward movement of the chair body, since the cam 109 will again disconnect the switch lever 7 5 from the operat-ing lever before the motor is connected to the supply circuit. If, however, the operating lever be moved in such av direction as to. start the motor in the direction necessary to lower the chair body, it will carry with it the switch lever 75 and cause closing of the contacts onthe controller necessary to cause operation of themotor as desired. I Y I For norma ly enclosing and protecting the above described mechanism, 1 mount on the base plate 1 a relatively heavy casing ring 110 fastened to the base 1 by'suitable bolts 111. ()n this ring rests thelower end of an enclosing casing 112, whose upper end extends under the downwardly flanged portion 7 of the chair body andhas a-central opening from, which depends a sleeve 113. On the upper end of this latter is fastened a ring 117 loosely resting on the uppe end of the casing 112 and designed to coact with v a second sleeve 114 whose. upper end is fixed to an outwardly extending flange of the tube 8 from which it depends; This second sleeve 114: has at its lower end an outwardly projecting flange 1115 designed toengage an inwardly projecting flange 116 at the upper end of the outer sleeve 113, so that as the chair body is elevated, tlie two. flanges 115 and 116 will come together, after which as the chair body continues to rise, the sleeve 113 will be drawn out of the main part 112 of the enclosing casing. As a result the elevatmg mechanism is completely enclosed, not only when the chair body is in its. lower position, but also in any of its elevated provide a plurality of books 118 pivoted;

on the inside of the depending part of the chair body 7 and designed to cooperate with outwardly projecting pins or lugs 119 on the upper end of the casing 112. As the chair body is elevated by the operation of the motor, the hooks 118 are moved into engagement with these pins so that said body carries with it the casing 112 and the sleeve 113. Access may thereupon be had to the motor and other parts of the associated apparatus.

1 claim. 7 c

1. The combination in chair elevating mechanism of a chair body; a motor; and. means for transmitting power from said, motor to raise the chair body comprising a supporting 7 structure; a fixed spindle mounted in said supporting structure; a gear driven by the motor and rotatably mounted on said spindle; a second gear rotatably mounted on. the first gear; and a slip clutch operatively connecting said gears under normal conditions.

2. The combination in chair elevating mechanism of. a supporting structure; a shaftjournaled therein; a motor having its casing formed to engage a portion of said supporting structure; the adjacent ends. of said shaft and the armature shaft of the motor being formed to separablyengage each other; and means for detachably clamping the motor to the supporting structure to maintain said shafts in operative connection, the same consisting of lugs on the motor, with a yolre mounted on the supporting structure and engaging said lugs to maintain the motor and supporting structure in engagement. 3. The combination in chair elevating mechanism of a supporting structure; ,a shaft journalled therein; a motor having its casing formed to engage a portion of said supporting structure; the adjacent ends of said shaft and the armature shaft of the motor being formed to be detachably coupled; and means for clamping the motor to the supporting structure to maintain said shafts inoperative connection, the same consisting of a pair of lugs on the motor; posts on, the supporting structure; a yoke fulcrumed on the posts and engaging the lugs; with a threaded member for holding the yoke in operative position.

1. The combination with a chair body of mechanism for raising said body; an enclosfor connecting the body to said casing comprising a hook to cause said casingto be raised with the body to exposesaid mechanism.

5. The combination with a chair body of mechanism for raising said body; a casing comprising telescoping members enclosing said mechanism and connected to the latter so as to be raised and lowered therewith; a main enclosing casing; and means including a hook for connecting said main casing to the body at will to cause it to be raised there with.

6. Apparatus comprising a pair of screws; a nut for one of said screws, the other of said screws engaging said nut; and means for preventing a relative longitudinal movement between said nut and said last-mentioned screw.

7. In combination, a pair of shafts adapted to be detaohably coupled; supporting members for the respective shafts, one of said members having a shoulder;and a fulcrumed element mounted on the other of said members and adapted to engage said shoul der, whereby said members may be secured in engagement.

8. In combination, a pair of shafts adapted. to be detachably coupled; supporting members for the respective shafts, one of said members having a shoulder; an element fulcrumed on the other of said members and positioned to engage said shoulder; and means for exerting-a force on said element, whereby said members may be secured in position.

9. In combination, a pair of shafts adapted to be oetachably coupled; supporting members for the respective shafts, one of said members having a shoulder; a post on the other member; an element fulcrumed on said post and engaging said shoulder; and

means for exerting a force on said element,

whereby said members may be secured in position.

10. In combination, a pair of shafts adapt ed to be detachably coupled; supporting members for the respective shafts, one of said members having a pair of shoulders; a yoke fulcrumed on the other of said members with the respective arms thereof in engagement with said shoulders; and means for exerting a force on said yoke, whereby said members may be secured in position.

11. In combination, a pair of shafts adapt ed to be detachably coupled; supporting members for the respective shafts, one of said members having a pair of shoulders; a yoke fulcrumed on the other of said members with the respective arms thereof in engage-- ment with said shoulders; and means extending from said first-mentioned member for exerting a force on said yoke, whereby said members may be secured in position.

12. In combination, a pair of shafts adapted to be detaohably coupled; supporting members for the respective shafts, one of said members having a pair of posts; a pair of lugs on the other member; a yoke fulcrumed on said posts and engaging said lugs; and a member for holding said yoke in such position as to secure said supporting members in position. i

13. Apparatus comprising a pair of hollow telescoping drive members; and a pipe positioned Within the inner member and supported at one end on the outer member, the other end of said pipe being in sliding engagement with the adjacent wall of the inner member.

14:. Apparatus comprising a pair of hollow telescoping drive members; a pipe positioned within the inner member and'supported at one end on the outer member: and

means for supplying a lubricant to the other end of said pipe.

15. Apparatus comprising a pair of chollow screws rotatably coupled in relative longitudinal movement; a pipe positioned with in the inner screw and supported at one end.

- on the outer screw; and means for supplying a lubricant to the other end of saidpipa- 7 l6. Chair elevating mechanism including a pair of screws; sleeves having portions re spectively engaging said screws, said sleeves having perforations; and means for supplying lubricant through said holes to the coacting surfaces of said sleeves.

anorrrr w. SGHRAMM.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2735477 *Aug 24, 1951Feb 21, 1956 Dental chair and the like
US2769511 *Apr 23, 1952Nov 6, 1956Hayes James HOne way brake
US4749177 *Mar 16, 1987Jun 7, 1988Siemens AktiengesellschaftPatient supporting table
EP0241701A1 *Mar 9, 1987Oct 21, 1987Siemens AktiengesellschaftPatient's positioning table
Classifications
U.S. Classification74/423, 188/82.9, 464/162, 254/103
International ClassificationA61G15/00, A61G15/02
Cooperative ClassificationA61G15/02
European ClassificationA61G15/02