US 3351379 A
Description (OCR text may contain errors)
Nov. 7, 1967 1 .J. STREET 3,351,379
CHAIRS Filed Feb. 1. 1966 FIG.2
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s I I! I gig-U z 2 L l 25 eu-rag LESLIE J'oHA/ STRE ET United States Patent 3,351,379 CHAIRS Leslie John Street, Bristol, England, assignor to The Tan- Sad Chair (Iompany (1931) Limited, Birmingham, England, a British company Filed Feb. 1, 1966, Ser. No. 534,939 Claims priority, application Great Britain, Feb. 13, 1965, 6,342/ 65 10 Claims. (Cl. 297-358) ABSTRACT OF THE DISCLUSURE An adjustable chair comprises a back-rest assembly and a seat assembly. A block, in which the upright stern of the back-rest assembly is vertically slidably mounted, is angularly adjustable about a horizontal axis on the seat assembly, there being cooperating serrated locking surfaces on the block and seat assembly. Adjustment of the stern relative to the block and the block relative to the seat assembly is controlled by a common bolt that extends rotatably through the block and a vertically elongated slot in the stem to a combined pivotal and threaded connection with the seat assembly. A U-shaped clamping member disposed between the bolt head and the block laterally encloses the block and stem.
This invention relates to chairs of the kind commonly known as typists chairs and comprising separate seat and back-rest assemblies.
The invention has for its object the provision in a typists chair of improved means for adjusting both the angular and height relationship between the seat and back-rest assemblies which means is of particularly simple construction, is cheap to manufacture, and is easily operated and maintained by the user.
In accordance with the invention a typists chair comprises seat and back-rest assemblies secured together through adjusting means including a block, complementary surfaces (preferably having complementary serrations) on the block and seat assembly capable of selective engagement to determine the angular position of the block in relation to the seat assembly about a horizontal axis, a dependant stem of the seat assembly abutting the block, and a bolt passing through a vertically elongated slot in the stem and through the block in a direction perpendicular to the complementary surfaces to have screw engagement with the seat assembly, the rotation of the bolt serving simultaneously to clamp the block in its selected angular position and to clamp the stem against said block at a selected height both in relation to the seat assembly.
A typical example of the practical realisation of the invention is illustrated in the accompanying drawings, wherein:
FIGURE 1 is a part-sectional side elevation showing the parts of a typists chair relevant to the invention, and
FIGURE 2 is a fragmentary and part-sectional plan View of certain of the parts of FIGURE 1 on an enlarged scale.
Referring to the drawings, a typists chair comprises a seat assembly including a die cast seat frame 3 adapted to surmount a pedestal and to carry a seat pad (both not shown) and a back-rest assembly including a pad 4 mounted on the head of a stem 5 of rectangular crosssection adapted for attachment to the seat frame 3 via an adjusting means.
The adjusting means comprises a block 6 having a flat rear face 7 and horizontally extending serrations 8 in a cylindrically concave front face protruding forwardly beyond a pair of cylindrically concave marginal portions 9. The block 6 has a bore 10 extending along a radius from Patented Nov. 7, 1967 the horizontal axis of curvature O of the cylindrically concave faces 8 and 9.
An integral rear portion 11 of the frame 3 is provided with inner and outer cylindrically convex regions 12 and 13 complementary to the concave faces 8 and 9 of the block, and the inner convex face 12 has serrations complementary to those of the block face 8. The serrated portion 12 of the seat frame embodies a vertically elongated slot 14.
The adjusting means further comprises a clamping member 15 of U-shape in horizontal cross-section having side flanges 25 shaped to overlap portions of the sides of the stem 5, the sides of the block 6, and marginal parts of the seat frame portion 11, thereby to conceal the major part of the block. The clamping member is formed with a central bore 16.
The adjusting means is completed by a bolt 17 which extends from an integral hand piece 18, forming the head of the bolt through the close fitting bore 16 in the clamping member, through a vertically elongated slot 19 in the stem 5, through the close fitting bore 10 in the block 6, and through the elongated slot 14 in the seat frame 3 to have screw engagement with an element in the form of a cylindrical cross-bar 20 journalled at the axis of curvature O of the serrated portions 8 and 12 and between a pair of flanges 21 integral with the seat frame. A pin or circlip 22 may be mounted in or about the bolt 17 to prevent accidental withdrawal of the bolt from the crossbar 2%).
In use, to adjust both the angle and height of the backrest assembly in relation to the seat frame assembly the hand piece 18 is manually rotated sufliciently to allow disengagement of the complementary serrated parts 8 and 12 and so permit angular movement together of the block 6, stem 5, clamping member 15, bolt 17 and cross bar 20 in relation to the seat frame 3 about the horizontal axis 0 within the limits determined by the available movement of the bolt 17 within the seat frame slot 14. Simultaneously the height of the back-rest stem 5 is adjusted by its sliding between the clamping member 15 and block 6. After selection of both the angle and height of the back-rest assembly the hand piece 18 is rotated in a direction to tighten the parts and to re-engage the complementary serrations 8 and 12 so as to lock the adjusting means in selected position.
Optionally a compression spring 23 can be mounted about the bolt 17 to abut between the cross-bar 20 and block 6 so as to bias the latter away from the seat frame 3 and so facilitate slackening of the parts.
Compared with previously known means for adjusting both the relative angles and heights of seat and back rest assemblies, that according to the invention is particularly simple, compact and positive in operation and requires no adjustment in use to take up the effects of wear other than that automatically alforded by the bolt 17 in its normal clamping function.
1. A chair for typists and the like comprising seat and back-rest assemblies secured together through adjusting means including a block, complementary surfaces on the block and seat assembly capable of selective locked engagement to determine the angular position of the block about a horizontal axis, a dependant stem of the seat assembly slidably connected to the block, a bolt passing through a vertically elongated slot in the stem and through the block in a direction substantially perpendicular to the complementary surfaces, and coacting means on said bolt and said seat assembly providing a combined pivotal and threaded connection therebetween whereby rotation of said bolt in one direction enables said complementary surfaces to be released and permits said block and bolt to swing together about said connection angularly relative to the seat assembly, and rotation of the bolt in the opposite direction serves simultaneously to clamp the block to the seat assembly in the selected angular position and to clamp the stem against the block at a selected height in relation to the seat assembly.
2. A chair according to claim 1 wherein the complementary surfaces have complementary serrations disposed on arcs substantially concentric with the pivot axis at said connection.
3. A chair according to claim 2 wherein said connec- 7 tion comprises a pivot element pivotally mounted about a generally horizontal axis in the seat assembly and having a threaded cross bore for screw engagement with the bolt.
4. A chair according to claim 3, wherein said pivot element is rotatably mounted in and between a spaced pair of flanges integral with a frame of the seat assembly.
5. A chair according to claim 1 comprising a clamping member disposed between a head of the bolt and the stem whereby when the bolt is rotated in said opposite direction the stem is clamped between the clamping member and said block.
6. A chair according to claim 5, wherein the head of the bolt takes the form of a manually rotatable hand piece.
7. A chair according to claim 5, wherein the bolt passes rotatably through close fitting apertures in the clamping member and block and through a vertically elongated gap in the seat assembly to permit rocking together of the clamping member, block, pivot element and bolt about the axis of said connection during adjustment.
8. A chair according to claim 5, wherein the clamping member is of U-shape in horizontal cross-section with side flanges overlying the sides of the stem and block.
9. A chair according to claim 2, wherein the block and seat assembly comprise second complementary and cylindrically curved surfaces coaxial with and horizontally spaced from the surfaces incorporating the serrations.
10. A chair according to claim 1 wherein spring means is compressed between the block and the seat assembly for urging said complementary surfaces apart When said bolt is rotated in said one direction.
References Cited UNITED STATES PATENTS 1,277,726 9/1918 Hunn 297358 1,696,153 12/1928 Bump 297-358 1,860,096 5/1932 Headley 297-358 2,137,335 11/1938 Gabb 297-358 2,421,702 6/1947 Jones 297358 2,590,718 3/1952 Lundquist 297375 X 2,845,994 8/1958 Thompson 297357 X DAVID J. WILLIAMOWSKY, Primary Examiner.
G. O. FINCH, Assistant Examiner.