Seat of adjustable height having an adjustable back
United States Patent 3880465
A stool or like body supporting device having a seat and a back, a first pneumatically expandable column supporting the seat on a base, and a second such column holding the back in a desired angular relationship to the seat is equipped with a single operating lever pivotally mounted on the seat for alternative engagement with the release pins of the two columns so that a user may adjust both the height of the seat and the slope of the back while manipulating the single lever.
US Patent References:
Position-retaining device
Martens - April 1964 - 3127788
Reclining chair
Kleinsorge - August 1967 - 3338632
Hydraulic adjustment barber chair
Watanabe - February 1968 - 3368845
SEAT ASSEMBLY
Downs et al. - February 1969 - 3427073
DENTAL CHAIR CONTROL
Maurer et al. - May 1970 - 3514153
Position-retaining device
Martens - April 1964 - 3127788
Reclining chair
Kleinsorge - August 1967 - 3338632
Hydraulic adjustment barber chair
Watanabe - February 1968 - 3368845
SEAT ASSEMBLY
Downs et al. - February 1969 - 3427073
DENTAL CHAIR CONTROL
Maurer et al. - May 1970 - 3514153
Application Number:
05/360088
Publication Date:
04/29/1975
Filing Date:
05/14/1973
View Patent Images:
Export Citation:
Assignee:
Stabilus GmbH (Koblenz, DT)
Primary Class:
Other Classes:
297/354.100, 248/631, 248/161
International Classes:
A47C1/024; A47C3/30; A47C1/022; A47C3/20; A47C7/40
Field of Search:
297/330,355,353,354,345 248/400,404,161
US Patent References:
Primary Examiner:
Frazier, Roy D.
Assistant Examiner:
Lyddane, William E.
Attorney, Agent or Firm:
Berman, Hans
Claims:
What is claimed is
1. A body supporting device comprising, in combination:
2. two longitudinally terminal portions respectively secured to said base and said seat assembly,
3. yieldably resilient first biasing means biasing said terminal portions to move relative to each other in a predetermined longitudinal direction,
4. first control means normally limiting the biasing action of said biasing means, and
5. first releasing means operatively connected to said control means and movable for inactivating said control means and thereby releasing said biasing means;
6. two longitudinally terminal portions respectively secured to said base and to said back,
7. yieldably resilient second biasing means biasing said terminal portions of said second column to move relative to each other in a predetermined longitudinal direction and for thereby pivoting said back,
8. second control means normally limiting the biasing action of said second biasing means, and
9. second releasing means operatively connected to said second control means and movable for inactivating said second control means and thereby releasing said second biasing means;
10. A device as set forth in claim 1, wherein each of said first and second releasing means includes a releasing member mounted on one of the two terminal portions of the associated column, the other terminal portion of said associated column being spaced from said releasing member in a direction away from the other column.
11. A device as set forth in claim 2, wherein each column includes an elongated cylinder having a longitudinal axis, and a piston rod axially projecting from said cylinder, respective axial end portions of said piston rod and of said cylinder constituting said longitudinally terminal portions.
12. A device as set forth in claim 3, wherein said seat assembly is mounted on the terminal portion of said first column carrying the releasing member of said first column, the terminal portion of said second column carrying the releasing member of said first column being secured to said seat assembly.
13. A device as set forth in claim 4, wherein the axes of the cylinders in said columns are approximately perpendicular to each other.
14. A device as set forth in claim 4, wherein said operating member is movably mounted on said seat assembly, said seat assembly and said first column constituting elements of said mounting means.
15. A device as set forth in claim 6, wherein said mounting means further include a pivot securing said operating member to said seat assembly for angular movement from an inoperative position in two opposite directions, said operating member during movement in said opposite directions respectively engaging said releasing means of said first and second column.
16. A device as set forth in claim 7, wherein the releasing means of one of said columns include a motion transmitting member operatively interposed between the releasing member of said one column and said operating member, said motion transmitting member and said operating member having respective cam faces engaging each other during said angular movement of the operating member in one of said opposite directions.
17. A device as set forth in claim 8, further comprising guide means on said seat assembly guiding said motion transmitting member in a direction having a major component axial relative to the cylinder of said one column.
18. A device as set forth in claim 2, said mounting means securing said operating member for angular movement from an inoperative position in two opposite directions, said operating member during angular movement from said inoperative position in one direction engaging the releasing member of one of said first and second releasing means, the other one of said first and second releasing means including a motion transmitting member operatively interposed between said operating member and the releasing member of the other releasing means for movement in a direction toward and away from said releasing member of the other releasing means, said operating member during angular movement from said inoperative position in the other direction engaging said motion transmitting member and moving the motion transmitting member toward said releasing member.
1. A body supporting device comprising, in combination:
2. two longitudinally terminal portions respectively secured to said base and said seat assembly,
3. yieldably resilient first biasing means biasing said terminal portions to move relative to each other in a predetermined longitudinal direction,
4. first control means normally limiting the biasing action of said biasing means, and
5. first releasing means operatively connected to said control means and movable for inactivating said control means and thereby releasing said biasing means;
6. two longitudinally terminal portions respectively secured to said base and to said back,
7. yieldably resilient second biasing means biasing said terminal portions of said second column to move relative to each other in a predetermined longitudinal direction and for thereby pivoting said back,
8. second control means normally limiting the biasing action of said second biasing means, and
9. second releasing means operatively connected to said second control means and movable for inactivating said second control means and thereby releasing said second biasing means;
10. A device as set forth in claim 1, wherein each of said first and second releasing means includes a releasing member mounted on one of the two terminal portions of the associated column, the other terminal portion of said associated column being spaced from said releasing member in a direction away from the other column.
11. A device as set forth in claim 2, wherein each column includes an elongated cylinder having a longitudinal axis, and a piston rod axially projecting from said cylinder, respective axial end portions of said piston rod and of said cylinder constituting said longitudinally terminal portions.
12. A device as set forth in claim 3, wherein said seat assembly is mounted on the terminal portion of said first column carrying the releasing member of said first column, the terminal portion of said second column carrying the releasing member of said first column being secured to said seat assembly.
13. A device as set forth in claim 4, wherein the axes of the cylinders in said columns are approximately perpendicular to each other.
14. A device as set forth in claim 4, wherein said operating member is movably mounted on said seat assembly, said seat assembly and said first column constituting elements of said mounting means.
15. A device as set forth in claim 6, wherein said mounting means further include a pivot securing said operating member to said seat assembly for angular movement from an inoperative position in two opposite directions, said operating member during movement in said opposite directions respectively engaging said releasing means of said first and second column.
16. A device as set forth in claim 7, wherein the releasing means of one of said columns include a motion transmitting member operatively interposed between the releasing member of said one column and said operating member, said motion transmitting member and said operating member having respective cam faces engaging each other during said angular movement of the operating member in one of said opposite directions.
17. A device as set forth in claim 8, further comprising guide means on said seat assembly guiding said motion transmitting member in a direction having a major component axial relative to the cylinder of said one column.
18. A device as set forth in claim 2, said mounting means securing said operating member for angular movement from an inoperative position in two opposite directions, said operating member during angular movement from said inoperative position in one direction engaging the releasing member of one of said first and second releasing means, the other one of said first and second releasing means including a motion transmitting member operatively interposed between said operating member and the releasing member of the other releasing means for movement in a direction toward and away from said releasing member of the other releasing means, said operating member during angular movement from said inoperative position in the other direction engaging said motion transmitting member and moving the motion transmitting member toward said releasing member.
Description:
This invention relates to a body supporting device having two columns of variable length operatively interposed between a base and, respectively, a seat assembly and a back, and more particularly to an operating arrangement for controlling the length of the columns.
It is known to mount the seat of a stool, of a passenger car or utility vehicle, and like body-supporting devices on a pneumatic or hydropneumatic column of adjustable length which permits the height of the seat to be adjusted. It is also known to provide such a body-supporting device with a tilting back whose angular position relative to the seat is maintained by means of a second column of the same type. A body of gas under pressure in each column tends to change the effective length of the column, and a control valve is provided to limit the biasing action of the gas. A releasing member outside the casing of the column is accessible for opening the normally closed control valve and for thereby changing the column length. A typical column of the type described has been disclosed in Axthammer U.S. Pat. No. 3,388,883.
In the known body-supporting devices which employ two such columns, separate operating elements are provided for the two columns and permit the seat height and the angle of the back to be adjusted to the shape and position of the supported body. For esthetic and other reasons, the two conventional operating elements are normally mounted out of the field of sight of a person whose body is supported on the seat, and it is inconvenient to grope for the two elements and to distinguish between them. An error in identification may have serious consequences if the driver's seat in a moving automotive vehicle is to be adjusted while the vehicle moves.
It is the primary object of this invention to provide a body-supporting device of the type described in which the height of the seat and the angle of the back may be adjusted after manipulating a single operating member only.
With this object and others in view, the body-supporting device of the invention comprises a base, a seat assembly, and a back connected to the base for pivoting movement relative to the seat assembly. The two longitudinally terminal portions of a first column of variable length are respectively secured to the base and the seat assembly, and the corresponding portions of a second such column are respectively secured to the base and the back. Each column further includes yieldably resilient biasing means which bias the terminal portions to move longitudinally relative to each other, a control device normally limiting the biasing action of the biasing means, and a releasing member operatively connected to the control device and movable for inactivating the same and thereby releasing the biasing means. A single operating member is movably mounted on the base for alternative engagement with each of the two releasing members and for thereby moving the engaged releasing member to inactivate the associated control device.
Other features, additional objects, and many of the attendant advantages of this invention will become better understood from the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which:
FIG. 1 is a fragmentary, side-elevational, and partly sectional view of a body supporting device of the invention;
FIG. 2 shows the device of FIG. 1 in fragmentary plan section on the line II -- II;
FIGS. 3 to 5 respectively illustrate the apparatus of FIG. 2 in fragmentary sections on the lines III -- III, IV -- IV, and V -- V;
FIG. 6 shows an element of the device in rear elevation;
FIG. 7 shows the element of FIG. 7 in side elevation; and
FIG. 8 shows a portion of the body supporting device largely omitted from FIG. 1 in elevational section.
Referring now to the drawing in detail, and initially to FIG. 1, there is shown only as much of a stool of the invention as is needed for an understanding of the invention. Only the top portion of the upright, tubular base 13g of the stool is visible in FIG. 1. The cylinder 13a of a first pneumatic, expandable column 13 movably projects upward from the base 13g and is connected to the supporting frame 40 of a seat cushion 14 by a coaxial extension tube 1. A single operating lever 4 projects outward of the tube 1 in a generally radial direction between two mounting brackets 20,29, and is fastened to the brackets by a pivot pin 5 for angular movement in a plane which includes the common vertical axis of the tube 1, the cylinder 13a, and the base 13g.
A bracket 44 is pivotally attached to the seat frame 40 by a pivot pin 44a remote from the tube 1, and the back 43 of the stool is fixedly attached to the bracket 44, and thereby pivotally secured to the base 13g. A second bracket, identical with the bracket 44, is obscured in the drawing, and also attached to the frame 40 by the pin 44a. A pin 41 connecting respective parts of the two brackets provides a pivot for an eye 42 at the axial end of an approximately horizontal cylinder 15a of a second pneumatic, expandable column 15. The piston rod 33 of the column 15 is hingedly attached to a fork 30 radially projecting from the tube 1, as will presently be described in more detail.
As is conventional in itself, the piston rod 33 carries a piston 15b in the cavity of the cylinder 15a and normally separates two axial compartments of the cavity. An axial bore 15c in the piston 15b connects the two compartments when a normally closed control valve 15d in the bore is opened by means of a linkage 15e extending in the piston 15b and the tubular piston rod 33 toward the tube 1, as shown in more detail in FIG. 2 of the afore-mentioned patent.
As is seen in FIG. 2, the outer end of the piston rod 33 is externally threaded, and a pivot head 9 is threadedly fastened on the rod 33 and secured in position by a locking nut 39. The linkage 15e, not otherwise seen in FIG. 2, terminates in a releasing pin 12 longitudinally movable in the rod 33 and carrying a spherically arcuate head or button. The pin 12 is obscured in FIG. 1 by the fork 30.
The tube 1 has three openings 24,25,26 in the common radial plane of FIG. 2. The openings 24,25 are diametrically opposite each other, and the opening 26 is angularly equidistant from the other two openings. The afore-mentioned brackets 20,29 are respective straight, parallel end portions of two flat bars 3,6 which pass through the opening 24 together with the lever 4. They are secured to each other and to the lever 4 by the aforementioned pin 5 and a retaining ring 2 on the pin. The circumferential width of the opening 24 is only sufficiently greater than the combined corresponding dimensions of the bars 3,6 and the lever 4 to permit the angular movement of the latter.
The other end portion 45 of the bar 3 and the end portion 19 of a flat bar 8 are jointly received in the opening 25 in conforming engagement with the walls of the opening. An intermediate portion 46 of the bar 3 is laterally offset from the end portions 29,45 for partial conforming engagement with the cylindrically concave inner wall of the tube 1 and for thus longitudinally securing the bar 3.
The bars 6 and 8 have each two leg portions offset at right angles to each other. The leg portion 23 of the bar 6 and the leg portion 21 of the bar 8 pass in spaced, parallel alignment outward through the opening 26 in the tube 1, and their free ends, offset away from each other jointly constitute the fork 30. Each of the free ends has a longitudinally open, longitudinal slot 31 whose inner end 32 is cylindrically enlarged. Integral pins 34 on the pivot head 9 are received in the enlarged slot portions 32, thereby pivotally connecting the rod 33 to the tube 1 and to the base 13g. A a motion transmitting push rod 7 passes through the opening 26 between the leg portions 21,23 with minimal circumferential clearance. A cam face 11 on the lever 4 in the tube 1 cooperates with the push rod 7 in a manner presently to be explained.
As is shown in FIG. 8, the cylinder 13a encloses an axially movable piston 13b from which a piston rod 13c passes axially downward through the bottom wall of the cylinder 13a into abutting engagement with the bottom wall of the generally cup-shaped base 13g. A conduit 13f is permanently open toward the compartment in the cavity of the cylinder 13a below the piston 13b, and has an orifice toward the upper cylinder compartment which is normally closed by another control valve 13e biased toward the closed position by a non-illustrated spring. A valve stem or releasing pin 17 passes upward from the valve 13e and axially out of the cylinder 13a in sealing engagement with the latter. The upper end portion of the cylinder 13a is provided with external threads 13h for engagement with mating threads of the tube 1.
The two compartments of the cylinder 13a are filled with compressed air which may hold the piston 13b in a position in which the forces of the gas acting on the two radial piston faces balance each other. When the valve 13e is opened, the connected gas portions act as yieldably resilient biasing means which tend to expel the piston rod 13c from the cylinder, and to increase the overall length of the column 13 by driving the cylinder 13a outward of the base 13g unless the gas pressure is overcome by a stronger external force driving the piston 13c inward of the cylinder, and the cylinder inward of the base 13g.
The combined weight of the seat frame 40 and, of portions of the stool attached to the frame 40 is insuffient to overcome the internal gas pressure in the cylinder 13a. When the valve 13e is opened by depressing the pin 17, the column 13 expands, and the seat cushion 14 is raised. The dimensions of the column 13 and the gas pressure are selected so that the weight of any adult seated on the cushion 14 can shorten the column 13 when the valve 13e is opened. Then the valve is closed, the biasing action of the gas in the cylinder 13a is limited to resilient response to the applied load. The full biasing action of the gas is released by the control valve 13e when the pin 17, acting as a releasing member, displaces the valve from the illustrated position.
The column 15 interposed between the seat back 43 and the tube 1 operates in the same manner. When the releasing pin 12 is pushed inward of the piston rod 33, the control valve 15d is opened, the biasing action of the gas in the cylinder 15a no longer is limited by the inactivated valve, and the back 43 is tilted clockwise, as viewed in FIG. 1, by the expanding column 15 unless the occupant of the seat pushes the back toward the position shown in broken lines while the valve 15d is open.
The portion of the pin 17 projecting from the column 13 is in the path of pivoting movement of the operating lever 4 in the tube 1, as best seen in FIG. 3. When the outer end of the lever 4, not itself seen in FIG. 4, is lifted, the pin 17 opens the valve 13e, and the seat frame 40 together with associated elements is raised unless sufficient opposite forces cause a shortening of the column.
Referring to FIGS. 5 and 6, it is seen that the push rod 7 has a longitudinal groove 18 which is guidingly engaged by a guide rib 22 of the leg portion 21. The part of the push rod 7 normally received in the tube 1 is axially wider than the leg portions 21,23, and the opening 26 of the tube 1 is shaped and dimensioned to confine the leg portions 21,23 and the enlarged part of the push rod 7 with just enough clearance to permit longitudinal movement of the rod 7. The inner end of the rod has an oblique cam face 16 located for cooperation with the cam face 11 of the lever 4 in such a manner that the rod 7, guided by the rib 22 and the walls of the opening 26 in a direction which has at least a major component axial relative to the cylinder 15a, is moved longitudinally outward of the opening 26 when the outer free end of the operating lever 4 is depressed. A concave abutment face 38 on the outer end of the rod 7 engages the head of the pin 12 under the pressure of a non-illustrated return spring acting on the valve 15d. The rod 7 thus transmits the motion of the lever 4 to the pin 12 and causes the valve 15d to be opened so that the angular position of the back 43 may be changed.
The assembly of the control mechanism for the illustrated stool is facilitated by the configuration of the integral pins 34 on the pivot head 9. As is best seen in FIGS. 6 and 7, the pins are of oblong cross section, having two flat long faces 35 connected by shorter convex faces. The width of the pins between the faces 35 is small enough to permit the pins 34 to be moved into the slots 31 in a position in which the threaded bore 47 of the head 9 is perpendicular to its position illustrated in FIG. 4. After the pins 34 enter the enlarged slot portions 32, the pivot head may be turned into its normal operating position, and may then be assembled with the piston rod 33 and the nut 39.
It will be appreciated that the bars 3,6,8 are to be assembled with the tube 1, to be followed by the lever 4 and the rod 7, before the pivot head 9 is installed and connected with the column 15. The sequence in which other elements of the stool are assembled is too obvious to require more detailed description.
While the back 43 and the lever 4 are mounted on the seat assembly constituted by the tube 1, the frame 40 and the cushion 14, and are connected to the base 13g by the seat assembly and the first column 13, the advantages of the invention are also available in devices in which the back and the operating lever are connected to the base 13g in any other manner, and the connection between the second column 15 and the base may have to be modified accordingly.
The disclosed columns 13,15 are preferred in a stool of the type disclosed, but neither their orientation nor their specific details are critical for achieving the desired simple and foolproof inactivation of their respective control valves 13e,15d. Either column may be inverted so that the cylinder 13a and the piston rod 33 are near each other. The cylinders of both columns may be near the tube 1, or the cylinders may both be remote from the tube 1, as is the cylinder 15a in the illustrative embodiment. The necessary changes in the valve arrangements will be obvious. Valve arrangements other than those specifically disclosed, but known in this art, may be substituted for the valve arrangements illustrated and described.
It should be understood, therefore, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the appended claims.
It is known to mount the seat of a stool, of a passenger car or utility vehicle, and like body-supporting devices on a pneumatic or hydropneumatic column of adjustable length which permits the height of the seat to be adjusted. It is also known to provide such a body-supporting device with a tilting back whose angular position relative to the seat is maintained by means of a second column of the same type. A body of gas under pressure in each column tends to change the effective length of the column, and a control valve is provided to limit the biasing action of the gas. A releasing member outside the casing of the column is accessible for opening the normally closed control valve and for thereby changing the column length. A typical column of the type described has been disclosed in Axthammer U.S. Pat. No. 3,388,883.
In the known body-supporting devices which employ two such columns, separate operating elements are provided for the two columns and permit the seat height and the angle of the back to be adjusted to the shape and position of the supported body. For esthetic and other reasons, the two conventional operating elements are normally mounted out of the field of sight of a person whose body is supported on the seat, and it is inconvenient to grope for the two elements and to distinguish between them. An error in identification may have serious consequences if the driver's seat in a moving automotive vehicle is to be adjusted while the vehicle moves.
It is the primary object of this invention to provide a body-supporting device of the type described in which the height of the seat and the angle of the back may be adjusted after manipulating a single operating member only.
With this object and others in view, the body-supporting device of the invention comprises a base, a seat assembly, and a back connected to the base for pivoting movement relative to the seat assembly. The two longitudinally terminal portions of a first column of variable length are respectively secured to the base and the seat assembly, and the corresponding portions of a second such column are respectively secured to the base and the back. Each column further includes yieldably resilient biasing means which bias the terminal portions to move longitudinally relative to each other, a control device normally limiting the biasing action of the biasing means, and a releasing member operatively connected to the control device and movable for inactivating the same and thereby releasing the biasing means. A single operating member is movably mounted on the base for alternative engagement with each of the two releasing members and for thereby moving the engaged releasing member to inactivate the associated control device.
Other features, additional objects, and many of the attendant advantages of this invention will become better understood from the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which:
FIG. 1 is a fragmentary, side-elevational, and partly sectional view of a body supporting device of the invention;
FIG. 2 shows the device of FIG. 1 in fragmentary plan section on the line II -- II;
FIGS. 3 to 5 respectively illustrate the apparatus of FIG. 2 in fragmentary sections on the lines III -- III, IV -- IV, and V -- V;
FIG. 6 shows an element of the device in rear elevation;
FIG. 7 shows the element of FIG. 7 in side elevation; and
FIG. 8 shows a portion of the body supporting device largely omitted from FIG. 1 in elevational section.
Referring now to the drawing in detail, and initially to FIG. 1, there is shown only as much of a stool of the invention as is needed for an understanding of the invention. Only the top portion of the upright, tubular base 13g of the stool is visible in FIG. 1. The cylinder 13a of a first pneumatic, expandable column 13 movably projects upward from the base 13g and is connected to the supporting frame 40 of a seat cushion 14 by a coaxial extension tube 1. A single operating lever 4 projects outward of the tube 1 in a generally radial direction between two mounting brackets 20,29, and is fastened to the brackets by a pivot pin 5 for angular movement in a plane which includes the common vertical axis of the tube 1, the cylinder 13a, and the base 13g.
A bracket 44 is pivotally attached to the seat frame 40 by a pivot pin 44a remote from the tube 1, and the back 43 of the stool is fixedly attached to the bracket 44, and thereby pivotally secured to the base 13g. A second bracket, identical with the bracket 44, is obscured in the drawing, and also attached to the frame 40 by the pin 44a. A pin 41 connecting respective parts of the two brackets provides a pivot for an eye 42 at the axial end of an approximately horizontal cylinder 15a of a second pneumatic, expandable column 15. The piston rod 33 of the column 15 is hingedly attached to a fork 30 radially projecting from the tube 1, as will presently be described in more detail.
As is conventional in itself, the piston rod 33 carries a piston 15b in the cavity of the cylinder 15a and normally separates two axial compartments of the cavity. An axial bore 15c in the piston 15b connects the two compartments when a normally closed control valve 15d in the bore is opened by means of a linkage 15e extending in the piston 15b and the tubular piston rod 33 toward the tube 1, as shown in more detail in FIG. 2 of the afore-mentioned patent.
As is seen in FIG. 2, the outer end of the piston rod 33 is externally threaded, and a pivot head 9 is threadedly fastened on the rod 33 and secured in position by a locking nut 39. The linkage 15e, not otherwise seen in FIG. 2, terminates in a releasing pin 12 longitudinally movable in the rod 33 and carrying a spherically arcuate head or button. The pin 12 is obscured in FIG. 1 by the fork 30.
The tube 1 has three openings 24,25,26 in the common radial plane of FIG. 2. The openings 24,25 are diametrically opposite each other, and the opening 26 is angularly equidistant from the other two openings. The afore-mentioned brackets 20,29 are respective straight, parallel end portions of two flat bars 3,6 which pass through the opening 24 together with the lever 4. They are secured to each other and to the lever 4 by the aforementioned pin 5 and a retaining ring 2 on the pin. The circumferential width of the opening 24 is only sufficiently greater than the combined corresponding dimensions of the bars 3,6 and the lever 4 to permit the angular movement of the latter.
The other end portion 45 of the bar 3 and the end portion 19 of a flat bar 8 are jointly received in the opening 25 in conforming engagement with the walls of the opening. An intermediate portion 46 of the bar 3 is laterally offset from the end portions 29,45 for partial conforming engagement with the cylindrically concave inner wall of the tube 1 and for thus longitudinally securing the bar 3.
The bars 6 and 8 have each two leg portions offset at right angles to each other. The leg portion 23 of the bar 6 and the leg portion 21 of the bar 8 pass in spaced, parallel alignment outward through the opening 26 in the tube 1, and their free ends, offset away from each other jointly constitute the fork 30. Each of the free ends has a longitudinally open, longitudinal slot 31 whose inner end 32 is cylindrically enlarged. Integral pins 34 on the pivot head 9 are received in the enlarged slot portions 32, thereby pivotally connecting the rod 33 to the tube 1 and to the base 13g. A a motion transmitting push rod 7 passes through the opening 26 between the leg portions 21,23 with minimal circumferential clearance. A cam face 11 on the lever 4 in the tube 1 cooperates with the push rod 7 in a manner presently to be explained.
As is shown in FIG. 8, the cylinder 13a encloses an axially movable piston 13b from which a piston rod 13c passes axially downward through the bottom wall of the cylinder 13a into abutting engagement with the bottom wall of the generally cup-shaped base 13g. A conduit 13f is permanently open toward the compartment in the cavity of the cylinder 13a below the piston 13b, and has an orifice toward the upper cylinder compartment which is normally closed by another control valve 13e biased toward the closed position by a non-illustrated spring. A valve stem or releasing pin 17 passes upward from the valve 13e and axially out of the cylinder 13a in sealing engagement with the latter. The upper end portion of the cylinder 13a is provided with external threads 13h for engagement with mating threads of the tube 1.
The two compartments of the cylinder 13a are filled with compressed air which may hold the piston 13b in a position in which the forces of the gas acting on the two radial piston faces balance each other. When the valve 13e is opened, the connected gas portions act as yieldably resilient biasing means which tend to expel the piston rod 13c from the cylinder, and to increase the overall length of the column 13 by driving the cylinder 13a outward of the base 13g unless the gas pressure is overcome by a stronger external force driving the piston 13c inward of the cylinder, and the cylinder inward of the base 13g.
The combined weight of the seat frame 40 and, of portions of the stool attached to the frame 40 is insuffient to overcome the internal gas pressure in the cylinder 13a. When the valve 13e is opened by depressing the pin 17, the column 13 expands, and the seat cushion 14 is raised. The dimensions of the column 13 and the gas pressure are selected so that the weight of any adult seated on the cushion 14 can shorten the column 13 when the valve 13e is opened. Then the valve is closed, the biasing action of the gas in the cylinder 13a is limited to resilient response to the applied load. The full biasing action of the gas is released by the control valve 13e when the pin 17, acting as a releasing member, displaces the valve from the illustrated position.
The column 15 interposed between the seat back 43 and the tube 1 operates in the same manner. When the releasing pin 12 is pushed inward of the piston rod 33, the control valve 15d is opened, the biasing action of the gas in the cylinder 15a no longer is limited by the inactivated valve, and the back 43 is tilted clockwise, as viewed in FIG. 1, by the expanding column 15 unless the occupant of the seat pushes the back toward the position shown in broken lines while the valve 15d is open.
The portion of the pin 17 projecting from the column 13 is in the path of pivoting movement of the operating lever 4 in the tube 1, as best seen in FIG. 3. When the outer end of the lever 4, not itself seen in FIG. 4, is lifted, the pin 17 opens the valve 13e, and the seat frame 40 together with associated elements is raised unless sufficient opposite forces cause a shortening of the column.
Referring to FIGS. 5 and 6, it is seen that the push rod 7 has a longitudinal groove 18 which is guidingly engaged by a guide rib 22 of the leg portion 21. The part of the push rod 7 normally received in the tube 1 is axially wider than the leg portions 21,23, and the opening 26 of the tube 1 is shaped and dimensioned to confine the leg portions 21,23 and the enlarged part of the push rod 7 with just enough clearance to permit longitudinal movement of the rod 7. The inner end of the rod has an oblique cam face 16 located for cooperation with the cam face 11 of the lever 4 in such a manner that the rod 7, guided by the rib 22 and the walls of the opening 26 in a direction which has at least a major component axial relative to the cylinder 15a, is moved longitudinally outward of the opening 26 when the outer free end of the operating lever 4 is depressed. A concave abutment face 38 on the outer end of the rod 7 engages the head of the pin 12 under the pressure of a non-illustrated return spring acting on the valve 15d. The rod 7 thus transmits the motion of the lever 4 to the pin 12 and causes the valve 15d to be opened so that the angular position of the back 43 may be changed.
The assembly of the control mechanism for the illustrated stool is facilitated by the configuration of the integral pins 34 on the pivot head 9. As is best seen in FIGS. 6 and 7, the pins are of oblong cross section, having two flat long faces 35 connected by shorter convex faces. The width of the pins between the faces 35 is small enough to permit the pins 34 to be moved into the slots 31 in a position in which the threaded bore 47 of the head 9 is perpendicular to its position illustrated in FIG. 4. After the pins 34 enter the enlarged slot portions 32, the pivot head may be turned into its normal operating position, and may then be assembled with the piston rod 33 and the nut 39.
It will be appreciated that the bars 3,6,8 are to be assembled with the tube 1, to be followed by the lever 4 and the rod 7, before the pivot head 9 is installed and connected with the column 15. The sequence in which other elements of the stool are assembled is too obvious to require more detailed description.
While the back 43 and the lever 4 are mounted on the seat assembly constituted by the tube 1, the frame 40 and the cushion 14, and are connected to the base 13g by the seat assembly and the first column 13, the advantages of the invention are also available in devices in which the back and the operating lever are connected to the base 13g in any other manner, and the connection between the second column 15 and the base may have to be modified accordingly.
The disclosed columns 13,15 are preferred in a stool of the type disclosed, but neither their orientation nor their specific details are critical for achieving the desired simple and foolproof inactivation of their respective control valves 13e,15d. Either column may be inverted so that the cylinder 13a and the piston rod 33 are near each other. The cylinders of both columns may be near the tube 1, or the cylinders may both be remote from the tube 1, as is the cylinder 15a in the illustrative embodiment. The necessary changes in the valve arrangements will be obvious. Valve arrangements other than those specifically disclosed, but known in this art, may be substituted for the valve arrangements illustrated and described.
It should be understood, therefore, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the appended claims.