EP0357578A1 - A chair base and post assembly for an office chair - Google Patents
A chair base and post assembly for an office chair Download PDFInfo
- Publication number
- EP0357578A1 EP0357578A1 EP89850272A EP89850272A EP0357578A1 EP 0357578 A1 EP0357578 A1 EP 0357578A1 EP 89850272 A EP89850272 A EP 89850272A EP 89850272 A EP89850272 A EP 89850272A EP 0357578 A1 EP0357578 A1 EP 0357578A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- socket
- hub
- post tube
- post
- base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C7/00—Parts, details, or accessories of chairs or stools
- A47C7/002—Chair or stool bases
- A47C7/004—Chair or stool bases for chairs or stools with central column, e.g. office chairs
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C5/00—Chairs of special materials
- A47C5/12—Chairs of special materials of plastics, with or without reinforcement
Definitions
- the invention is directed to a chair base and post assembly for an office chair in which the chair base is formed in one piece of injection molded plastic.
- An object of this invention is a chair base and post assembly in which a steel post is mounted in a plastic hub and is supported so as to transfer its load vertically onto the hub with the hub also stabilizing the post tube against tilting.
- Another object of this invention is a plastic chair base having a hub with a socket that permits easy removal of the molding tools yet provides non-tapered annular bearing surfaces to stabilize a steel post tube which is positioned in the socket.
- Another object of this invention is a plastic chair base having a hub with a socket in which the hub itself provides a lower annular bearing surface to stabilize a steel post tube positioned in the socket and a steel sleeve near the upper end of the socket provides another annular bearing surface to stabilize the post tube.
- Fig. 1 of the drawings is a cross-sectional view showing a chair base and post assembly 11 embodying the novel features of this invention.
- the chair base and post assembly includes a hub 13 with five integral arms 15 which are formed in one piece by injection molding of plastic.
- the arms are molded of thin walled, somewhat parabolic cross-section with honeycombed reinforcing ribs and ejection pin tubes 16, as shown in Figs. 1 and 3 of the drawings.
- Any suitable high strength plastic may be used to injection mold the integral base and arms.
- a plastic found to be suitable is nylon resin plastic sold by E.I. du Pont de Nemours & Co. under the designation "Zytel 72G33 nylon resin.”
- a socket 17 formed in the hub 13 extends therethrough from top to bottom.
- a steel post tube 19 is mounted in the socket and projects upwardly above the socket.
- a pneumatic lift cylinder 21 telescopes inside and projects upwardly beyond the top of the steel post tube.
- a plastic guide bushing 23 seats in the upper end of the steel post tube to guide and stabilize the pneumatic lift cylinder.
- a collar 25 which is formed integrally with the plastic guide bushing rests on the upper end of the steel post 19.
- Ribs 27 spaced around the outer periphery of the plastic guide bushing below the collar 25 engage the inside surface of the steel post tube 19 to prevent the plastic guide bushing from rotating inside the steel post tube.
- the ribs 27 are notched partially at 29 just below the collar 25.
- a scalloped steel washer 31 is welded at 32 to the outside of the steel post tube 19.
- five cutouts 33 are formed in the washer, with each cutout being positioned between a pair of converging arms 15 extending from the hub 13 of the chair base, as can be best seen in Fig. 3 of the drawings.
- the scalloped washer fits into a corresponding scalloped notch 35 formed in the top of the hub 13 and rests on a shoulder 37 defining the bottom of the notch to thereby transfer the weight of the post tube 19 vertically onto the hub 13.
- the remainder of the socket 17 below the scalloped notch 35 is of irregular cross-section and includes a slightly tapered cylindrical portion or counterbore 39 located below the shoulder 37.
- the taper which provides draft for removal of the molding tool from the cylindrical portion 39 need only be approximately 0.5 degrees.
- a shoulder 41 defines the lower portion of the slightly tapered cylindrical portion 39.
- a convergently tapered portion 43 extends downwardly from the shoulder 41 and a cylindrical portion 45 without any taper is formed at the lower end of the socket 17.
- the cylindrical portion 45 provides an annular wall which engages the outer wall of the steel post tube 19 to stabilize the post tube against lateral moving or tilting.
- a steel sleeve 47 having a cylindrical inner wall 49 which engages the cylindrical outer wall of the steel post tube 19, is positioned in the cylindrical portion 39 and rests on the shoulder 41.
- the outer wall 51 of the steel sleeve 47 has a taper corresponding to the taper of the cylindrical portion 39 so that the sleeve 47 is fully contacting the slightly tapered cylindrical portion 39 of the hub.
- the outer surface of the wall of the steel post tube 19 does not engage the socket wall in the space between the steel sleeve 47 and the lower cylindrical portion 45 of the hub.
- a cylindrical washer 55 is welded to the steel post tube just inside the lower end of the tube.
- the cylindrical washer has an opening 57 in the center thereof.
- a steel hat washer 59 having a center opening 61 which aligns with and is the same diameter as the center opening 57 of the cylindrical washer 55 is force fitted into an annular notch 63 formed at the lower end of the hub and engages the cylindrical washer 55.
- the pneumatic lift cylinder 21 has a piston rod 67 extending out of the bottom and a plastic actuating button 68 at the top thereof.
- the rod has an end portion 69 of reduced diameter providing a downwardly facing annular shoulder 71.
- the shoulder 71 rests on a ball bearing assembly 73 which is supported on the cylindrical washer 55 welded to the post tube 19 near the bottom thereof.
- the reduced diameter end portion 69 of the piston rod extends through the openings 57 and 61 in the washers 55 and 59, respectively, and projects out of the bottom of the post tube 19.
- a clip 75 fits into a notch 77 formed in the end portion 69 of the piston rod 67 and secures it against upward movement.
- a resilient rubber washer 79 is positioned between the bottom of the lift cylinder and the ball bearing assembly.
- the upper end of the pneumatic lift cylinder 21 is tapered to fit into a socket located on the underside of a chair seat, but which is not shown.
- Caster sockets 81 are formed in the ends of the arms 15 to receive conventional chair casters which are not shown.
Landscapes
- Chairs Characterized By Structure (AREA)
- Chair Legs, Seat Parts, And Backrests (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Hydrogenated Pyridines (AREA)
- Nitrogen Condensed Heterocyclic Rings (AREA)
Abstract
Description
- The invention is directed to a chair base and post assembly for an office chair in which the chair base is formed in one piece of injection molded plastic.
- An object of this invention is a chair base and post assembly in which a steel post is mounted in a plastic hub and is supported so as to transfer its load vertically onto the hub with the hub also stabilizing the post tube against tilting.
- Another object of this invention is a plastic chair base having a hub with a socket that permits easy removal of the molding tools yet provides non-tapered annular bearing surfaces to stabilize a steel post tube which is positioned in the socket.
- Another object of this invention is a plastic chair base having a hub with a socket in which the hub itself provides a lower annular bearing surface to stabilize a steel post tube positioned in the socket and a steel sleeve near the upper end of the socket provides another annular bearing surface to stabilize the post tube.
- These objects are achieved with the device defined in the following claims.
- The invention is illustrated more or less diagrammatically in the following drawings wherein:
- Fig. 1 is a vertical cross-sectional view through the chair base and post assembly;
- Fig. 2 is an enlarged cross-sectional view taken along line 2-2 of Fig. 1 with some parts omitted for clarity of illustration;
- Fig. 3 is a top plan view of the chair base and post assembly of Fig. 1 with some parts broken away and others omitted for clarity of illustration;
- Fig. 4 is a bottom plan view of the chair base and post assembly of Fig. 3; and
- Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 3.
- Fig. 1 of the drawings is a cross-sectional view showing a chair base and post assembly 11 embodying the novel features of this invention. The chair base and post assembly includes a
hub 13 with fiveintegral arms 15 which are formed in one piece by injection molding of plastic. The arms are molded of thin walled, somewhat parabolic cross-section with honeycombed reinforcing ribs andejection pin tubes 16, as shown in Figs. 1 and 3 of the drawings. Any suitable high strength plastic may be used to injection mold the integral base and arms. A plastic found to be suitable is nylon resin plastic sold by E.I. du Pont de Nemours & Co. under the designation "Zytel 72G33 nylon resin." Asocket 17 formed in thehub 13 extends therethrough from top to bottom. Asteel post tube 19 is mounted in the socket and projects upwardly above the socket. Apneumatic lift cylinder 21 telescopes inside and projects upwardly beyond the top of the steel post tube. A plastic guide bushing 23 seats in the upper end of the steel post tube to guide and stabilize the pneumatic lift cylinder. To secure the plastic guide bushing in position at the upper end of thesteel tube 19, acollar 25 which is formed integrally with the plastic guide bushing rests on the upper end of thesteel post 19.Ribs 27 spaced around the outer periphery of the plastic guide bushing below thecollar 25 engage the inside surface of thesteel post tube 19 to prevent the plastic guide bushing from rotating inside the steel post tube. Theribs 27 are notched partially at 29 just below thecollar 25. - A
scalloped steel washer 31 is welded at 32 to the outside of thesteel post tube 19. In this example of the invention, fivecutouts 33 are formed in the washer, with each cutout being positioned between a pair of convergingarms 15 extending from thehub 13 of the chair base, as can be best seen in Fig. 3 of the drawings. The scalloped washer fits into a correspondingscalloped notch 35 formed in the top of thehub 13 and rests on ashoulder 37 defining the bottom of the notch to thereby transfer the weight of thepost tube 19 vertically onto thehub 13. - The remainder of the
socket 17 below thescalloped notch 35 is of irregular cross-section and includes a slightly tapered cylindrical portion orcounterbore 39 located below theshoulder 37. The taper which provides draft for removal of the molding tool from thecylindrical portion 39 need only be approximately 0.5 degrees. Ashoulder 41 defines the lower portion of the slightly taperedcylindrical portion 39. A convergentlytapered portion 43 extends downwardly from theshoulder 41 and acylindrical portion 45 without any taper is formed at the lower end of thesocket 17. Thecylindrical portion 45 provides an annular wall which engages the outer wall of thesteel post tube 19 to stabilize the post tube against lateral moving or tilting. To stabilize thepost tube 19 at the upper end of thehub 13, asteel sleeve 47, having a cylindricalinner wall 49 which engages the cylindrical outer wall of thesteel post tube 19, is positioned in thecylindrical portion 39 and rests on theshoulder 41. Theouter wall 51 of thesteel sleeve 47 has a taper corresponding to the taper of thecylindrical portion 39 so that thesleeve 47 is fully contacting the slightly taperedcylindrical portion 39 of the hub. As can be seen from the drawings, the outer surface of the wall of thesteel post tube 19 does not engage the socket wall in the space between thesteel sleeve 47 and the lowercylindrical portion 45 of the hub. - A
cylindrical washer 55 is welded to the steel post tube just inside the lower end of the tube. The cylindrical washer has anopening 57 in the center thereof. Asteel hat washer 59 having acenter opening 61 which aligns with and is the same diameter as the center opening 57 of thecylindrical washer 55 is force fitted into anannular notch 63 formed at the lower end of the hub and engages thecylindrical washer 55. - The
pneumatic lift cylinder 21 has apiston rod 67 extending out of the bottom and aplastic actuating button 68 at the top thereof. The rod has anend portion 69 of reduced diameter providing a downwardly facingannular shoulder 71. Theshoulder 71 rests on aball bearing assembly 73 which is supported on thecylindrical washer 55 welded to thepost tube 19 near the bottom thereof. The reduceddiameter end portion 69 of the piston rod extends through theopenings washers post tube 19. Aclip 75 fits into anotch 77 formed in theend portion 69 of thepiston rod 67 and secures it against upward movement. Aresilient rubber washer 79 is positioned between the bottom of the lift cylinder and the ball bearing assembly. - As is conventional, the upper end of the
pneumatic lift cylinder 21 is tapered to fit into a socket located on the underside of a chair seat, but which is not shown.Caster sockets 81 are formed in the ends of thearms 15 to receive conventional chair casters which are not shown.
Claims (3)
a socket (17) extending vertically through the hub,
said socket being of irregular cross-section decreasing in diameter from the top to the bottom,
a non-tapered annular wall (45) located near the bottom of the socket (17) to engage a post tube (19) to be inserted in the socket to stabilize the post tube against lateral movement,
a slightly tapered enlarged counterbore (43) at the top of the socket to receive a sleeve (47) to engage the post tube to stabilize it, and
the portion of the socket between the counterbore and the non-tapered annular wall being tapered so as to be out of contact with the post tube inserted in the socket.
said base is formed in a single piece of plastic,
said socket (17) having an irregular cross-section,
said post tube (19) being cylindrical and positioned in said socket and extending out of said socket above said hub,
means (31) is attached to the outside of said post tube (19) and rest on said hub (13) to support said post tube (19),
annular internal surfaces (39, 45) are located in the socket (17) near the top and bottom thereof to engage said post tube to stabilize it against lateral movement,
said annular internal surface located in the socket near the bottom thereof being formed as a non-tapered internal wall (45) of the hub and said annular internal surface located in the socket near the top thereof being formed as the internal wall of a sleeve (47) seated in the counterbore (39) in the socket near the top thereof, and
means (55, 59) located at the bottom of said post tube (19) to support a pneumatic lift cylinder (21) positioned in said post tube.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT89850272T ATE68079T1 (en) | 1988-09-01 | 1989-08-25 | BASE AND PILLAR FOR AN OFFICE CHAIR. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US23946288A | 1988-09-01 | 1988-09-01 | |
US239462 | 1988-09-01 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0357578A1 true EP0357578A1 (en) | 1990-03-07 |
EP0357578B1 EP0357578B1 (en) | 1991-10-09 |
Family
ID=22902239
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89850272A Expired - Lifetime EP0357578B1 (en) | 1988-09-01 | 1989-08-25 | A chair base and post assembly for an office chair |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0357578B1 (en) |
JP (1) | JPH02114912A (en) |
AT (1) | ATE68079T1 (en) |
DE (1) | DE68900316D1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5454536A (en) * | 1994-01-13 | 1995-10-03 | Westinghouse Electric Corporation | Chair base assembly |
DE4415056A1 (en) * | 1994-04-29 | 1995-11-02 | Link Wilhelm Kg | Chair esp. work chair or office chair |
AU729048B2 (en) * | 1996-11-05 | 2001-01-25 | Dynafurn A Division Of Lincoln Sentry Group Pty Ltd | Chair base |
US11375817B2 (en) * | 2019-04-04 | 2022-07-05 | Medway Plastics Corporation | Apparatus and methods for the understructure of a chair base |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH430098A (en) * | 1964-02-12 | 1967-02-15 | Kemmann & Koch | Foot part for furniture, in particular seating furniture |
DE1296760B (en) * | 1966-02-08 | 1969-06-04 | Roeder Soehne Vorm Haberle & C | Height-adjustable column, especially swivel chair column |
GB2021940A (en) * | 1978-05-31 | 1979-12-12 | Kinnarps Kontormoebler | Chair seat column |
-
1989
- 1989-08-25 EP EP89850272A patent/EP0357578B1/en not_active Expired - Lifetime
- 1989-08-25 DE DE8989850272T patent/DE68900316D1/en not_active Expired - Fee Related
- 1989-08-25 AT AT89850272T patent/ATE68079T1/en active
- 1989-08-30 JP JP1224341A patent/JPH02114912A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH430098A (en) * | 1964-02-12 | 1967-02-15 | Kemmann & Koch | Foot part for furniture, in particular seating furniture |
DE1296760B (en) * | 1966-02-08 | 1969-06-04 | Roeder Soehne Vorm Haberle & C | Height-adjustable column, especially swivel chair column |
GB2021940A (en) * | 1978-05-31 | 1979-12-12 | Kinnarps Kontormoebler | Chair seat column |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5454536A (en) * | 1994-01-13 | 1995-10-03 | Westinghouse Electric Corporation | Chair base assembly |
DE4415056A1 (en) * | 1994-04-29 | 1995-11-02 | Link Wilhelm Kg | Chair esp. work chair or office chair |
AU729048B2 (en) * | 1996-11-05 | 2001-01-25 | Dynafurn A Division Of Lincoln Sentry Group Pty Ltd | Chair base |
US11375817B2 (en) * | 2019-04-04 | 2022-07-05 | Medway Plastics Corporation | Apparatus and methods for the understructure of a chair base |
US11793310B2 (en) | 2019-04-04 | 2023-10-24 | Medway Plastics Corporation | Apparatus and methods for the understructure of a chair base |
Also Published As
Publication number | Publication date |
---|---|
ATE68079T1 (en) | 1991-10-15 |
EP0357578B1 (en) | 1991-10-09 |
DE68900316D1 (en) | 1991-11-14 |
JPH02114912A (en) | 1990-04-27 |
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