US2711632A - Release-relief valve for adjustable chairs - Google Patents

Description

June 28, 1955 c. A. ELLIS RELEASE-RELIEF VALVE FOR ADJUSTABLE CHAIRS 5 Sheets-Sheet 1 Filed Jan. 12, 1949 ELLIS INVENT CHARLES A 7' ATTORNEY June 28, 1955 c. A. ELLIS 2,711,632

RELEASE-RELIEF VALVE FOR ADJUSTABLE CHAIRS Filed Jan. 12,1949 5 Sheets-Sheet 2 1N NTOR ATTORNEY June 28, 1955 c. A. ELLIS RELEASE-RELIEF VALVE FOR ADJUSTABLE CHAIRS Filed Jan. 12, 1949 5 Sheets-Sheet 3 R o T N E v m CHARLLES A. ELL|$ 2g 3 BY ATTORNEY June 28, 1955 c. A. ELLIS V RELEASE-RELIEF VALVE FOR ADJUSTABLE CHAIRS Filed Jan. 12, 1949 5 Sheets-Sheet 4 \NVENTOR A. ELUS CH ARLES ATTORNEY June 28, 1955 v c. A. ELLIS RELEASE-RELIEF VALVE- FOR ADJUSTABLE CHAIRS 5 Shets-Sheet 5 Fild Jan. 12, 1949 INVENTOR CHARLES ELL\S- ATTQRNEY United States Patent RELEASE-RELIEF VALVE FOR ADJUSTABLE CHAIRS Charles A. Ellis, Southbridge, Mass., assignor to American Optical Company, Southbridge, Mass., a voluntary association of Massachusetts Application January 12, 1949, Serial No. 70,499

2 Claims. (Cl. 6052) This invention relates to improvements in adjustable chairs and has particular reference to adjustable chairs such as are used in the practice of optometry, dentistry and the like.

A principal object of this invention is to provide an adjustable chair having improved automatic electro-hydraulic lifting means embodying an electrically operated pump controlling a hydraulic system for raising the chair to the desired height upon operation of simple control means therefor, and improved means for lowering the chair at a controlled rate of speed. I

Another object is to provide a chair 'of the above character having automatic electro-hydraulic means for raising and lowering the chair to the desired height, with safety means being provided to insure efiicient and safe operation of the hydraulic system in the event of failure of the lifting mechanism to function properly.

Another object is to provide an adjustable chair having improved automatic electro-hydraulic lifting means embodying an electrically operated pump controlling a hydraulic system for raising the chair to the desired height upon operation of simple electrical control means therefor by the operator, with safety means embodying a relief valve mechanism adapted to operate automatically to relieve undulyhigh pressure built up in the lifting mechanism and so insure safe operation without damage to the chair mechanism in the event of failure of the mechanism to function properly, and means embodying a metering valve mechanism for lowering the chair at a controlled rate of speed by the operator.

It is a further object of the invention to provide an adjustable chair of the above character which is rela- 2,711,632 Patented June 28, 1955 usually operated by a hand lever or a foot pedal. The result has been that inconvenient and time-consuming operations are necessary in adjusting the chair, and it is frequently necessary to make such adjustments several times before securing the proper desired position. Considerable time is consumed and considerable manual labor "ice " also is involved in adjusting chairs of the conventional tively inexpensive, comparatively simple in its construction and efiicient in its operation.

Other objects and advantagesof the invention will become apparent from the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of an adjustable chair embodying the present invention;

Fig. 2 is a fragmentary sectional view showing the operating mechanism in the chair base;

'Fig. 3 is a fragmentary top plan view partly in section Prior art hydraulically operated chairs have consisted generally of a. hydraulically actuated lift embodying a piston reciprocable in a cylinder' and moved therein by the pressure of a hydraulic fluid. The fluid is drawn from a fluid chamber or reservoir and pressures are built up upon the fluid by means of a manually actuated pump 3-.

= having means for automatically lifting the chair to the desired height upon operation of simple and efficient elec-' trical control means and for lowering the chair at a controlled rate of speed upon operation of separate control means.

Referring to the drawings wherein like characters of reference designate like parts throughout the several views, the invention is embodied in a chair having a base 10, a pedestal 11, seat portion 12 with attached apron 13, foot rest 14, arm rests 15, back rest 16 and head rest 17. The base is formed in a conventional manner as an ornamental ringlike member 18 having its inner contour edge portion 19 (Fig. 5) raised above the floor on which the chair is set. The pedestal 11 is provided with a series of bosses 20 around its lower inner edge and is adapted to rest upon the upper side of the portion 19 of the base ring member 18, with aligned threaded openings being provided in the portion 19 and bosses 20 for reception of bolts 21 for securing the pedestal to the base.

A vertically disposed tubular support 22 is vertically movable over a hydraulic lift cylinder 23 and at its upper end carries the chair seat portion 12 and associated parts, the seat portion 12 being rotatable and adapted to tilt about the hinge 24 (Fig. 6) through conventional mechanism not shown. The arm rests 15, back rest 16 and head rest 17 are also adjustable through conventional mechanism and, therefore, are not described further herein.

A disclike base 25 is carried by a plurality of arms 26 extending inwardly from the inner walls of the pedestal adjacent its lower edge, the base 25 having arms 27 extending radially therefrom adapted to overlie the under sides of the arms 26 (Fig. 5) and having vertical openings 28 therein concentric with smaller threaded openings in the arms 26. Bolts 29 are adapted to extend through the openings 28 to connect the arms 27 to respective base arms 26, and a pair of upper and lower resilient shock absorbers 30 of rubber or other suitable type of resilient material are mounted over the bolts and have portions extending within the openings 28 and overlying the adjacent upper and lower surfaces of the arms 27, with collars 31 mounted over the bolts 29 adjacent their head portions 32 serving to retain the lower shock absorbers 30 in place. Thus, any vibration of the operative parts of the machine will'be absorbed by the rubber mountings and will not be transmitted from the base 25 to the pedestal 11.

The base 25 has a partially threaded opening 33 formed in its upper surface in which is threaded the lower end of an inner tubular member 34 (Fig. 4) and has a cap 35 threadedly mounted over its upper end, thecap 35 being of larger diameter than the tubular member 34 and formed with a peripheral shoulder 35c against which the upper end of the outer hydraulic lift cylinder 23 is adapted to abut, with the lower end of the cylinder 23 being disposed within a circular ring-like boss 36 formed on the upper surface of the supporting disc and encircling the opening 33 therein. Thus, there is formed an inner chamber 37 within the tubular member 34' and a reservoir 38 externally of the member 34 but within the cylinder 23, with oil seals 39 provided adjacent the areas of connection between the parts of the device to prevent leakage of oil or other fluid from the chamber 37 or reservoir 38. The reservoir can be filled through a vertical opening 35:: provided through the cap 35, which opening is sealed by a threaded plug 35b.

, A piston 40 is mounted for vertical movement within the inner chamber 37 and has a rod 41 extending therethrough, With a portion of the rod 41 projecting beneath the piston 40, the portion of the rod 41 inside the piston 40 being reduced in size to form a shoulder 42 against which the upper surface of the piston rests, with means such as a castellated nut and cotter pin arrangement 43 located over the lower end of the rod 41 to retain the piston 40 in place. The upper portion of the rod 41 is of a length to extend upwardly through an opening in the cap member 35 and has a depression 44 formed in its upper end in which is seated a ball member 45. A hub 46 provided with a hollow 48 therein is formed on the under side of a disc 47 and is mounted over the upper end of the rod 41 with the bottom of the hollow 48 resting on the ball 45. The disc 47 has a resilient disc 49 of rubber or other resilient material secured to its upper surface which serves to resiliently support the tubular support 22 which is concentrically located with clearance about the cylinder 23 and vertically movable over it. The disc 49 serves to mechanically isolate the support 22 so that no vibration will be transmitted to the chair seat from the operative units within the pedestal. Oil seals 50 are provided in the piston 40 and cap member 35 for preventing leakage.

of fluid, similarly to the seals 39 and a series of openings 34a are provided adjacent the upper end of the member 34 to permit escape of any fluid which might manage to find its way into the chamber 37 above the piston 40. The upper end of the tubular support 22 carries the seat 12 and associated parts of the chair as hereinbefore described.

The upper end of the pedestal 11 is formed with a vertically extending tubular bearing 51 (Fig. 6) in which the support 22 is adapted to slide, the support 22 being provided with a keyway 52 adapted to be engaged by a key (not shown) formed on or secured to the inner surface of the bearing 51 to restrain the support 22 from rotary movement in the bearing 51 while permitting free vertical movement thereof.

. An electrical motor 53 of suitable type is mounted in resilient vibration absorbing bearings 54 forming a part of a support 55 located on the base 25, and has an operating shaft 53a operatively connected by a flexible vibration reducing coupling 56 to the operating shaft 57a of a pump 57 also secured to the base 25. The pump 57 is of conventional type and is used to pump oil or other fluid to the lifting device through conduits 58 and 59 (Figs. 3 and 4), the conduit 58 being in the shape of flexible tubing connecting the pump 57 to the base and the conduit 59 being formed as a bore internally of the base 25 and communicating with the conduit 58 and with the opening 33 leading to the chamber 37 in the lifting device.

. The motor 53 is of conventional design and is connected to a suitable source of current and to a manually operable switch arrangement (Figs. 6 and 7) located so as to be easily accessible to the operator. The switch 60 is of conventional normally open type and is fixedly carried by a projection 61 formed on a supporting plate 62, the projection 61 extending rearwardly of the plate 62 through an opening in the pedestal 11. The projection 61 has a depending portion 63 to which a foot lever 64 is hinged as at 65, the lever 64 extending through an opening 66 in the plate 62 and having a foot pad 67 secured to its outer end for engagement by the foot of the operator. The inner end of the lever 64 is adapted to engage the operating member 68 of the switch. Thus, by depressing the lever 64 with his foot, the operator will cause the inner end of the lever 64 to actuate the operating member 68 and close the switch 60 which, through suitable wiring 69, will cause energization of the motor 53 and responsive operation of the pump 57. The pump 57 will force the hydraulic fluid through conduits 58 and 59 into the lift cylinder chamber 37, causing a high pressure to be built up sutficiently to force the piston 40 upwardly and thereupon raise the tubular support 22 and upper portions of the assembled chair, with a check valve 58a (Fig. 2) being provided to prevent the fluid from flowing in the reverse direction when the pump is inoperative.

The piston 40 and chair will continue to rise until the operator releases the foot lever 64, opening the switch 60, deenergizing the motor 53 and stopping the pump 57. However, in the event that the operator continues to press the foot lever 64, or in case of faulty operation of the mechanism, there is provided means for releasing the high pressure built up in the device by continuedfunetioning of the pump, thus preventing breakage of parts of the device. This means is embodied in a cylindrical housing 69 mounted vertically on the base 25 adjacent the the lifting cylinder and secured thereto as by bolts 70. The housing 69 is closed at its upper end and is disposed with its lower end over an opening 71 leading to the conduit 59. The opening 71 is threaded for reception of a plug 72 which is screwed therein and which is provided with a central vertical bore 73 therethrough, the bore having a beveled upper edge indicated by the numeral 74.

A vertically extending tubular member 75 is provided with a lower end portion 76 of a size and shape to fit within the bore 73 in the plug 72 and having a beveled portion 74 shaped to rest evenly upon the beveled edge 74a of the plug bore 73 as a valve seat. The tubular member 75 has a chamber 77 therein into which the fluid under high pressure from conduit 59 is permitted to pass through bores 73 and 71. The housing 69 is preferably formed as separate upper and lower sections joined as at 78 so that the adjacent abutting portions may be threaded internally for reception of a block 79 having a vertical bore 80 therein.

A plug 81 is threaded into the upper end of the tubular member 75 and has a vertical bore 82 therein concentric with and of smaller diameter than the upper portion of the chamber 77. The chamber 77 has a coiled spring 83 disposed thereinfor retention of a ball plug member 84 over the lower end of the bore 82 in the plug 81, the lower end of the spring 83 being adapted to rest upon shoulders 84a formed by a bore 84b communicating with the lower end of the chamber 77, which bore 8417 also communicates with the bore 73. Thus, the fluid will be permitted to enter the chamber 77 from conduit 59 through bores 71, 73 and 84d but will be prevented front leaving by the ball 84 which is held over the end of the bore 82 by the spring 83. A coil spring 85 encircles the tubular member 75 and has its upper end disposed in a groove 86 formed in the lower surface of the block 79, its lower end resting upon the shoulder formed by an enlarged portion 87 of the tubular member 75. Thus, the tubular member 75 is continually urged downward by the spring 85 to provide a seal between the adjacent conical surfaces 74 and 74a formed on the end portion 76 thereof and the opening 73 in the plug 72.

Upon operation of the foot lever 64 by the operator, the pump will operate to force fluid through conduits 58 and 59 into the lifting device, as described, and simultaneously into the chamber 77 of the tubular member 75. In the event of continued operation of the pump to raise the chair beyond its limit of movement, the pressure of the fluid in the chamber 77 will be built up to such an extent that the pressure of the spring 85 will be overcome and the tubular member will be forced upwardly within the block 79. This will draw the lower end portion 76 of the tubular member upwardly, providing a space between the conical surfaces 74 and 74a, which will permit the fluid to pass from the high pressure. chamber 77 into a low pressure chamber 88 formed by the walls of the housing 69, thus relieving the pressure within the chambers 37 and 77, the fluid then passing through a series of openings 89 provided in the base (Fig. 3) and communicating with a conduit 90, one end of which communicates with the reservoir 38 within the lift cylinder 23. Thus, the fluid can return to the reservoir directly from the chamber 88 and is adapted to flow from the reservoir to the pump 57, upon operation thereof, through additional conduits 91 and 92.

Conventional oil seals 93 are provided within the housing 69 at various points for preventing leakage of the hydraulic fluid at these points.

The present invention includes a metering valve arrangement for lowering the chair from a raised position at a controlled rate of speed. A foot lever 94 is provided externally of the pedestal 11 at a point easily accessible to the operator and is attached to one end of a cam shaft 95 (Fig. 6) rotatably supported in a boss 96 formed on the inner surface of the pedestal, the inner end of the cam shaft 95 carrying a cam 97 which is, positioned above and in close proximity to a rod 98 (Fig. 4) extending vertically through an opening in the top of the housing 69. The rod 98 is adapted to be mounted for vertical movement in the housing 69, having its lower end positioned in a vertical opening in the upper end of the block 79 and having a collar 99 fixedly secured thereto as by a pin 100, the collar 99 having a flange 101 formed integral therewith and adapted to rest against the under surface of the top of the housing 69. A coiled spring 102 is positioned about the rod 98 with its upper end resting against the flange 101 of the collar 99 and with its lower end abutting the block 79. Thus, the spring 102 will serve to maintain the rod 98 in position as illustrated in Fig. 4, and upon depression of the foot lever 94 by the operator, and consequent rotation of the cam shaft 95 and cam 97, the cam 97 will engage the upper end of the rod 98 and will depress the rod 98 against the tension of the spring 102.

The lower end of the rod 98 is provided with a depression 103 of a size and shape for reception of the upper end of a vertically disposed valve operating member 104. The member 104 is of such length as to be spaced slightly away from the bottom of the recess 103 at its upper end to allow a slight play between the parts of t the device, and has its lower portion extending through the bore 82 in the plug 81 carried by the upper end of the tubular member 75, with its lower end resting against the ball 84" sealing the end of the bore 82. The lower end of the rod 104 is of a diametrical size substantially that of the bore 82 but tapers upwardly to a thin portion approximately midway thereof. Thus, upon downward movement of the rod 98 in response to depression of the foot lever by the operator, the bottom of the recess 103 in the rod 98 will engage the upper end of the member 104 and will force it downwardly. This downward movement of the member 104 will also push the ball 84 downwardly against the tension of the spring 83 and, due to the taper of the member 104, fluid from the high pressure chamber 77 will flow into the bore 82 and from there it will proceed through a series of openings 105 in the plug 81 into the low pressure chamber 88, and from there into the reservoir through conduit 90.

It will be understood that upon relief of the high pressure Within the chamber, this relief will also be felt by t obvious that if the member 104 is urged downwardly to a considerable extent a considerable amount of the fluid will be permitted to pass into the bore 82, while if the member 104 is moved only a slight distance downwardly, the amount of fluid passing into the bore 82 will be small.

In the event that the chair is lowered fast it is possible that the conduit will be unable to accommodate the entire amount of fluid permitted to escape at once from the high pressure chamber 77. Therefore, the block 79 is provided with a series of vertical bores 106 therethrough (Fig. 4) so that the fluid can also temporarily pass upwardly into the space formed in the upper portion of the housing 69 above the block 79.

While the conduits 59, 90 and 91 are all formed by boring longitudinally into the material of the base 25, it is to be understood that these conduits may be formed of flexible hose similar to the conduits 58 and 92 if desired.

The foregoing describes an improved adjustable chair produced in accordance with the objects of this invention, wherein there is provided a chair with electrohydraulic means for raising the chair to the desired height, with safety means embodying a relief valve for preventing damage in the event that the chair raising mechanism continues to operate after the chair has reached its uppermost limit of movement, and with a metering device under control of the operator for controlling the extent of downward movement of the chair and speed of the chair as it is lowered.

It is to be understood that the mechanism for raising and lowering the chair, and the safety means operable therewith, may be used with articles other than adjustable chairs such as instrument stands or like articles having members to be raised and lowered.

While the novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the formation and details of the device illustrated, and in its operation, may be made by those skilled in the art without departing from the spirit of the invention.

I claim:

1. In a hydraulic system the combination of a base having two pairs of seats, one arranged within the other, and a pair of conduits, one connecting the inner seat of each pair and the other connecting the outer seat of each pair, a high pressure chamber mounted on the inner one of each of said pairs of seats and a low pressure chamber mounted on the outer one of each of said pairs of seats, and a pump having leads connecting it with said pair of conduits for forcing fluid from the low pressure chambers to the high pressure chambers, valve means in the lead connecting the pump with the conduit connecting the two inner seats, said valve means permitting fluid to flow into said high pressure chambers under action of the pump from the low pressure chambers but not to return through the pump, one of said high pressure chambers having a piston mounted therein for movement in response to the pumping of fluid into said high pressure chamber, and said other high pressure chamber having gate means communicating with the surrounding low pressure chamber and operable to permit the flow of fluid out of said high pressure chamber to the surrounding low pressure chamber.

2. In a hydraulic system the combination of a base having two pairs of seats, one arranged within the other, and a pair of conduits, one connecting the inner seat of each pair and the other connecting the outer seat of each pair, a high pressure chamber mounted on the inner one of each of said pairs of seats and a low pressure chamber mounted on the outer one of each of said pairs of seats, and a pump having leads connecting it with said pair of conduits for forcing fluid from the low pressure chambers to the high pressure chambers, valve means in the lead connecting the pump with the conduit connecting the two inner seats, said valve means permitting fluid to flow into said high pressure chambers under action of the pump from the low pressure chambers but not to return through the pump, one of said high pressure chambers having a piston mounted therein for movement in response to the pumping of fluid into said high pressure chamber, and said other high pressure chamber having gate means adjacent its upper end communicating with the surrounding low pressure chamber and operable to permit the flow of fluid out of said high pressure chamber to the surrounding low pressure chamber and further being raisable ofi its seat against spring means urging it to remain on said seat when the fluid in said high pressure chambers and connecting conduit 15 2,445,334

exceeds a maximum pressure to permit fluid to thereby automatically enter the surrounding low pressure chamber to relieve said excess pressure.

References Cited in the file of this patent UNITED STATES PATENTS Miller et aI Mar. 19, 1929 1,887,328 Russell Nov. 8, 1932 1,953,606 Hobson Apr. 3, 1934 1,959,682 May May 22, 1934 2,059,130 May Oct. 27, 1936 2,095,286 Riach Oct. 12, 1937 2,132,363 Thomas Oct. 4, 1938 2,215,666 Meitzler Sept. 24, 1940 Page July 20, 1948

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