US2267963A - Portable chair - Google Patents

Description

Dec. 30, 1941.

D. A. WHITE ET AL PORTABLE CHAIR Filed Oct. 21, 1940 2 Sheets-Sheet 1 Demo, 1941. 5. A. WHITE ETAL 2,267,963

PORTABLE CHAIR Filed Oct. 2l, 1940 2 Sheets-Sheet 2 Patented Dec. 3%, 1941 PORTABLE CHAIR Application October 21, 1940, Serial No. 382,124 In Canada August 28, 1940 14 Claims.

This invention relates to portable chairs and more particularly to dental chairs for use in the field.

The object of the invention is to provide an improved chair of simple and inexpensive construction which is of the required strength and capable of all the adjustments which may be necessary during the performance of dental operations. The improved chair comprises a minimum number of parts the majority of which are preferably made of metal tubes in such a way that the chair provides maximum strength with minimum weight.

With these objects in view the invention consists in the combination and arrangement of parts hereinafter fully described and more particularly pointed out in the appended claims.

Referring now to the accompanying drawings which illustrate, by way of example, one convenient embodiment of the invention:

Figure 1 is a side elevation of the improved chair in erect, operative position,

Figure 2 is a front elevation partially in section on the line 22 of Figure l,

Figine 3 is a plan view of the seat,

Figure 4 is a plan view of the foot-rest,

Figure 5 is a section on line 5-5 of Figure 2,

Figure 6 is a side elevation showing the chair in partially collapsed or folded position and Figure 7 is a side elevation indicating the completely folded position of the chair,

In the illustrated form the chair comprises a pair of parallel front legs I rigidly connected by a transverse bar 2 and formed at the top with axially aligned bearings 3. rear legs 4 are rigidly connected by a horizontal bar 5 and are formed at the top with aligned bearings i. The bearings 3 and 6 are mounted on axially aligned shafts or spindles i. Shafts or spindles 3 are formed at their lower ends with bearings 9 which are also mounted on the spindles I. An inverted U-shaped back member H! of tubular construction is provided and the lower or open ends of this member are telescoped on to the spindles 8, the back member Iii being provided with any suitable reinforcement such as horizontal bars I l and i2 and means forincreasing the surface area for supporting the sitters back, for example, plates is connected to the horizontal bars I! and I2.

The back member it may be raised or lowered on the spindles 8 and suitable means are provided for holding the back securely in adjusted position. These means may conveniently comprise a bar Hi formed with a number of inclined A pair of parallel notches it, one or another of which is adapted to be engaged by the middle part of the bar I2. The notched bar i l may be formed on a plate It connected rigidly to downwardly diverging bars ll formed with bearings it mounted on the inner ends of the spindles l.

The spindles l are keyed to the bearings 6 by means of vertical tubes l9 inserted through registering borings in the bearings and the spindles.

A seat member is pivotally mounted on the back member iii. The seat member may conveniently comprise a metal sheet Ell welded at its front and side edges to a partially rectangular tubular frame 23, reinforced by parallel tubes 22 which extend rearwardly of the seat. The back of the seat between the tubes 22 can be flanged I downwardly to stiffen it in any suitable manner. The tubes 22 are curved upwardly at the rear ends and formed with aligned bearings 23 and with lateral stops or projections 2 The bearings 23 are mounted on aligned studs 25 carried by or formed on the back member iii. The projections 2s engage the rear of the back member 56 and form the sole means for supporting the seat in operative position with respect to the back member.

Suitable means are provided for supporting the back in any desired angular position. The means illustrated for this purpose comprise telescoping members 26 and 21 respectively formed with bearings 28 and 29, pivotally mounted on the bars H and 5 respectively. Any convenient means are provided for locking the-telescoping members 23 and 2! in adjusted positionand these means may conveniently take the form of perforated plates 3% loosely pivoted on a loop 3! in turn pivotally connected at 32 to the top of the tube 2?. The member 28 passes through holes in the plates 38 which are urged apart by a spring 33, to cause the edges of the holes in the plates 36 to engage the member 26 and restrain it against axial movement except when the plates 3i? are manipulated towards each other against the action of the spring 33.

Any convenient form of head-rest is mounted on the top of the back member iii. The headrest may comprise a canvas sheet 34 stretched between metal holders pivoted at E5 on a U-shaped member 36 formed with a bar 37 mounted adjustably in a bore in an angularly adjustable bearing 38. The bearing 38 is carried by a rod 39 mounted in a lug til in which it can be locked by means of a bolt M. This head-rest is of known construction and need not be described in further detail.

The opening of the pairs of legs I and 4 is limited by any convenient tension means such as a bar 42 pivotally mounted at 43 on the bar 2 and detachably connectable, as by a hook 44, to an eyelet or loop 45 carried by the bar 5.

The leg-rest may comprise a U-shaped member 46 pivotally connected at 41 to the bar 2. The parallel parts of member 45 are joined by a transverse rod 43 on which are pivotally mounted legs 49 formed with laterally projecting stops 50 arranged to engage the underside of the member 46 when the legs 49 are in erect position. A foot-bar is carried by parallel bars 52 held in place on the bar 48 by means of loops 53 carried by the bars 52 and through which the bar 48 passes. The bars 52 are formed on their underside with pairs of holes 54 with one or another of which engage a pair of projections 55 carried by the central transverse part of the V-shaped member 46. It will be seen that the foot-bar 5| can be raised or lowered by moving the bars forwardly or backwardly and engaging the projections 55 in one or another of the pairs of holes 54.

The legs I, 4 and 49 are preferably formed or provided with suitable anti-slip devices, rubber feet 56 being illustrated for this purpose.

A table support 51 may be detachably mounted in one or other of the tubes I9 and a small instrument table 58 of any suitable form may be detachably mounted on the top of this support.

It is believed that the method of erecting the chair into operative position will be clear from an inspection of Figures 1 and 2. The angular position of the back of the chair with respect to the legs can be readily effected simply by pinching the locking members 30 together to release the bar 26. The entire back with the seat can then be pivoted either forward or back on the spindles I to the desired new position. The locking members 39 are then released and automatically enter into engagement with the bar 26 to lock it in the new position.

When it is necessary to raise or lower the seat 20 the locking members 30 are released and the back member ID with the parts carried thereby can then be raised or lowered to bring the bar l2 into engagement with the desired notch l5. It will be seen that when the back is raised to bring the bar l2 out of the notch I5, the bar I6 is free to move forwardly on the pivot spindles I. When the back has been raised or lowered to the desired new position the bar I6 is moved rearwardly so that the bar |2 can enter into engagement with the notch I5 which is nearest to the desired new position of the back.

As the head-rest is of known construction it is not necessary to describe its operation.

It is believed that the operation of the footrest will be obvious. When adjustment of this device is required it is simply necessary to grasp the foot-bar 5| and lift it to release the bars 52 from the projections 55 and, by pulling the bar 5| forwardly it is forced to rise by the curved formation of the rear ends of the bars 52. When the bar 5| has been raised or lowered to the desired new position it is released and the projections 55 engage the nearest pair of holes 54 to hold the foot-bar in the adjusted position.

When the chair is to be folded the head-rest is first removed by loosening the bolt 4| and the table 58 is lifted from its support 51 and the latter is lifted from the tube I9. The seat 29 can be folded up against the back and the member 26 can be drawn completely out of the member 21 by pinching the locking members 30. The hook 44 on the bar 42 is released from the loop 45 and the chair is then in condition for folding. The various parts of the chair are shown approaching the folded position in Figure 6 and the completely folded position is indicated approximately in Figure 7.

It will be seen that the invention provides a chair of great strength and minimum weight which can be adjusted to any desired position by a few very simple operations and that the chair is capable of being folded into a very small and compact form so that it can be readily transported.

It will be understood that the foregoing description and accompanying drawings are given by way of example only and that any modifications within the scope of the appended claims may be resorted to without departing from the scope of the invention.

It will be understood that in the description and claims the term bar will usually signify metal tube. The invention is not limited'to the use of tubular members, although in most cases they will of course be preferable on account of their smaller weight.

What we claim is:

1. A portable chair comp-rising foldable front and rear legs pivotally mounted on a horizontal axis at their upper ends, a vertically adjustable back member also pivotally mounted on said axis, a seat pivotally mounted on said back member, means also pivotally mounted on said axis, for supporting said back member in any one of a number of positions of vertical adjustment, a strut member of adjustable length pivotally associated at its ends with said back member and rear legs, means for holding the front and back legs in open position with respect to each other.

2. A portable chair as claimed in claim 1, wherein the legs consist of a pair of front legs rigidly connected by a bar and a pair of rear legs rigidly connected by a bar, each leg being formed at its upper end with a bearing, a pair of axially aligned spindles being provided'on which said bearings are mounted.

3. A portable chair as claimed in claim 1, wherein the legs consist of a pair of front legs rigidly connected by a bar and a pair of rear legs rigidly connected by a bar, each leg being formed at its upper end with a bearing, a pair of axially aligned spindles being provided on which said bearings are mounted, and wherein means are provided for preventing axial movement of said spindles with respect to said legs.

4. A portable chair as claimed in claim 1, wherein the legs consist of a pair of front legs rigidly connected by a bar and a pair of rear legs rigidly connected by a bar, each leg being formed at its upper end with a bearing, a pair of axially aligned spindles .being provided on which said bearings are mounted, and wherein small tubes are secured in aligned holes in' each of said spindles and one of the bearings thereon.

5. A portable chair as claimed in claim 1 wherein said back member comprises an inverted U-shaped tube and a pair of spindles or shafts telescopically engaging the ends of said tube, and said spindles being provided with bearings on their lower ends, said bearings being pivotally mounted on the same axis as the legs.

6. A portable chair as claimed in claim 1 wherein said back member comprises an inverted U-shaped tube and a pair of spindles or shafts telescopically engaging the ends of said tube, and said spindles being provided with hearings on their lower ends, said bearings being pivotally mounted on the same axis as the legs, and wherein said tubular back member is formed with aligned trunnions or studs and wherein a rigid seat member is provided with axially aligned bearings pivotally mounted on said trunnions or studs.

7. A portable chair as claimed in claim 1 wherein said back member comprises an inverted U-shaped tube and a pair of spindles or shafts telescopically engaging the ends of said tube, and said spindles being provided with bearings on their lower ends, said bearings being pivotally mounted on the same axis as the legs, and

wherein said tubular back member is formed with aligned trunnions or studs and wherein a rigid seat member is provided with axially aligned bearings pivotally mounted on said trunnions or studs, and wherein said seat member comprises a partially rectangular tube and rearwardly extending reinforcing members in which the seat bearings are provided, a sheet of suitable material being attached at its edges to said partially rectangular tube, and the rear ends of said reinforcing members being curved upwardly and offset laterally.

8. A portable chair as claimed in claim 1 wherein said back member comprises an inverted U-shaped tube and a pair of spindles or shafts telescopically engaging the ends of said tube, and said spindles being provided with bearings on their lower ends, said bearings being pivotally mounted on the same axis as the legs, and wherein a notched supporting member is provided at its lower end with a pair of arms formed at their lower ends with aligned bearings pivotally mounted on the same axis as the legs, the notches in said notched member being arranged to be selectively engaged by a part carried by the U-shaped back member.

9. A portable chair as claimed in claim 1, wherein the back member and rear legs each have a transverse bar, said adjustable strut member comprising a pair of telescopically engageable members having at their outer ends bearings mounted on said transverse bars, readily releasable means being provided to lock said telescopic means in adjusted position.

10. A portable chair as claimed in claim 1, wherein the legs consist of a pair of front legs rigidly connected by a bar and a pair of rear legs rigidly connected by a bar, each leg being formed at its upper end with a bearing, a pair of axially aligned spindles being provided on which said bearings are mounted, and wherein an adjustable foot-rest is pivotally associated with the bar connecting the front legs.

11. A portable chair as claimed in claim 1,

wherein the legs consist of a pair of front legs rigidly connected by a bar and a pair of rear legs rigidly connected by a bar, each leg being formed at its upper end with a bearing, a pair of axially aligned spindles being provided on which said bearings are mounted, and wherein an adjustable foot-rest is pivotally associated with the bar connecting the front legs, and wherein said foot-rest comprises a U-shaped bar, a pair of legs pivoted to said bar, a foot-bar connected to a pair of rearwardly projecting bars resting on said U-shaped bar and loosely attached thereto, the rear ends of said rearwardly projecting bars being curved so that forward movement of said curved bars results in upwardly movement of said foot-bar, means being provided to hold the foot-bar detachably in adjusted position.

12. A folding chair comprising a pair of front legs and a pair of back legs pivotally connected together coaxially at their upper ends, an inverted U-shaped back member mounted for pivotal movement about the same axis as the legs,

' a seat member pivotally mounted on said back member, means whereby said back member may be moved to and detachably secured in any one of a plurality of vertical positions for the purpose of adjusting the height of the seat member, and a strut member pivotally connected with the back member and the back legs, said strut member being adjustable in length to adjust the angular position of the back member with respect to the legs.

13. A folding chair comprising a pair of front legs, a pair of back legs and a back member all mounted for pivotal movement about a common axis, a seat member pivotally mounted on said back member, a notched supporting member mounted on the same axis as the back and leg members, and a member of adjustable length associated with said back member and back legs, the back member comprising an upper part telescopically connected with a lower part, and the upper part of the back member having a part 1 arranged to engage one or another of the notches in said supporting member to hold the upper part of the back in the desired position of vertical adjustment.

14. A folding chair comprising a rigidly connected pair of front legs, a rigidly connected pair of back legs and a back member all mounted for pivotal movement about a common axis, and a seat member having rearwardly projecting parts pivoted to said back member and provided with lateral projections arranged to engage the rear of the back member, said lateral projections forming the sole means for holding the seat member in open or operative position.

DONALD ALLEN WHITE. MAURICE BERNARD KENT.

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