GB2206191A - An adjustable arm - Google Patents

Abstract

An adjustable arm structure for supporting lamps, books etc. comprises articulated first and second limbs each comprising a pair of parallel members one of which is coupled to a respective sector plate at the articulated joint between the two limbs, and the sector plates being movably coupled relative to each other and being releasably lockable to each other. <IMAGE>

Description

Adjustable Arm Structures Background Of the Invention The invention set fortl in this specification pertains to new and improved adjustable arm structures.

Adjustable arm structures of the type to which this specification pertains are commonly uscd in offices, drafting rooms and various other related locations to support a lamp of one sort or another in such a manner that the position of the lamp may be easi]y and conveniently adjusted. They are also commonly used to hold or support document holders such as so called "copy stands" which are often employed to hold a document so that a typist can copy from it Such arm structures are also on occasion used for a variety- of other purposes such as in holding magnifying lens, in holding part trays, in holding various tools and the like.

Although adjustable arm structures used in holding such items hay: been constrcted in a variety of different ways, it is considered that they kave normally been constructed 0 as to each include first and second elongated arm assemblies, a connections joint for connecting two adjacent ends of the arm assemblies, a mounting joint for use in mounting the entire arm structure on a table, a desk or the like located at the non-connected end of the first arm assembly and a holding joint for holding an item such as a lamp located at the non-connected end of the second arm structure.In such an adjustable arm structure the arm assemblies have usually been constructed so as to each include two parallel links and the ends of these links have beeri pivotally connected to the various joints indicated.

li sucl an adjustable arm structure it is conventional to use a spring - normally a coiling spring - so that it extends between a link of the first arm assembly and this mounting join: ar,d to use another corresponding spring so that this second spring extends bctwccn the connccting joint and a link of the second arm assembly. Such springs will tend to exert forces countering gravity in such a manner that the arm structures are relative stable in virtually any position to which they can be adjusted.It is also conventional to provide a conventional handle and threaded connections in association with the connecting joint and a link of the second arm assembly to enable the link to be clamped relative to the connecting joint so as to prevent adjustment of the position of the arm assembly Adjustable arm structures as indicated in the preceding paragraph are unquestionably highly utilitarian in character. NeverdAeless it is believed that there has been a need to improve such structures so that they can be easily and conveniently locked in such a manner that adjustment of the position of the arm assemblies in such structures is effectively precluded. The reason for this need can be readily illustrated with refere,rce to structures as indicated in the preceding.In such structures it is frequently difficult toadequately tighten a h::1dle as noted in order to apply sufficient force to preclude movement when or as a relatively large weight is applied to a holding joint. Such a weight can take the fonn of a relatively heavy lamp, a heavy book or the like depending upon the use of a specific adjustable arm structure.

Brief Summarv Of the Tn"enn A broad objective of the present invention is to provide new and improved adjustable arm structures alleviating the need indicated in the preceding discussion. In meting this need the invention is intended to provide arm structures as noted with can be easily and conveniently manufactured at a comparatively nominal cost which may be easily used by even non-mechanically oriented personnel, and whict ire cap.tble'of being intensivcly eniploycd for prolonged pcriods with little or no maintenance.

In accordance with this invention these objcctives are achicved by providing an adjustable arm structure which includes first and second elongated arm assemblies located relative to one another so as to have adjacent ends and remote ends, connecting joint means connecting the adjacent ends of said assemblies, a mounting joint means for use in mounting said structure located at the remote end of said first arm, a holding joint means for supporting an item located at the remote end of said second arm, each of said arm assemblies including first and second parallel links, said links of said first arm assembly being pivotally connected to mounting joint means and said connecting joint means, said links of said second arm assembly being pivotally connected to said holding joint means and said connecting joint means, in which the improvement comprises: said connecting joint means including frame means, said links of said arm assemblies being pivotally connected to said frame means, said connecting joint means also including a first sector plate attached to a link of said first arm assembly and a second sector plate attached to a link of said second arm assembly, said sector plates extending parallel to one anttiler, said connecting joint means also-including securing means extending between said sector plates for securing said sector movement relative to one another so as to hold said arm assemblies against movement changing the distance between the links in said arm assemblies.

Brief Description Of The Drawings Because of the nature of the present invention it is best more fully described by referring to the accompanying drawings in which: Fig. 1 is a side etevational view of a presently preferred embodiment or form of an adjustable arm-structure in accordance with the invention; Fig. 2 is a fragmentary view coiTespond:-ng to a part of Fig. 1 at an enlarged scalc; Fig. 3 is a partial cross-sectional view taken at line 3-3 of Fig. 2; and Fig. 4 is a partial cross-sectional view taken at line 4-4 of Fig. 3.

The precise adjustable arm structure shown in the drawings is constructed so as to utilize the operative concepts or principles of the invention as are sent forth in the accompanying claims. Those skilled in the field of adjustable arm structures of the type to which this invention pertains will realize that these concepts or principles can be applied in other somewhat differently appearirg and/or constructed adjustable arm structures through the use or exercise or routine skill in th field of such structures. For this reason the invention is not be considered as being limited to the precise structure illustrated and is to be considered as being limited solely by the appended claims forming a part of this invention.

Detailed Description Of the Preferred Embodiment In the drawing there is shown an adjustable arm structure 10 in accordance with this invention It is considered that it is best described. by indicating in a generalized manner the principal parts of assemblies employed in it. This structure 10 is constructed so as to include a first elongated am assembly 12, a second elongated arm assembly 14, a connecting joint or joint means 16 which is constructed as hereinafter indicated so as to connect the adjacent ends ls and 20, respectively, of the assemblies 12 and 14, a mounting joint or joir,t means 22 connected to an end of the first arm assembly 12 and a holding joint or joint means 25 connected to an end of the second arm assembly 14.

The mounting joint means 22 is used to hold the complete structure 10 on a support such as a desk or table in a conventional manner. The holding joint means 26 is used to support an item 30 held by the complete structure 10 such as a lamp, a copy holder or ant other desired item. It is not considered necessary to d scr '.r either the joint 22 or tlic joint 26 in detail inasmuch as both are constructed in a mechanically conventional manner.

The joint 22 includes a conventional pin or shaft 32 capable of being rotatably supportc1: in a conventional holder (not shown). This pin 32 extends from between two parallel plates 34. Only one of these plates 34 is visible in Fig. 1, the other being directly behind it.

Pivot pins 36 extend betç, cen these plates 34 for the purpose of pivotally mounting links 38 and 40 of the first arm assembly 12 in a conventional manner. If desired these plates 3A, the pins 36 and the ado cent portions of the links 38 and 40 can be considered as constituting the end 24. Normally tabs 42 extending from the plates 34 will be used in a conventional manner to connect coi! springs 44 between the joint 22 and a tab 45 on a link of the assembly 12 such as the link 38 as shown. Only one of these tabs 42 and one of the springs 44 is shown in Fig. 1; the others being directly behind them and therefore are not visible.If desired various functional equivalents can, of course, be substituted for the springs 44.

The joint 24 is constructed-in a manner which is similar to the manner in which the joint 22 is constructed. It also included parallel plates 46 which carry a small conventional member 45 used to support an item 30 in a known manner. Only one Gf these plates 46 is visible in Fig. 1, the other being located directly behind the one which is visible; Other pivot pins 36 extend between these plates 46 so as to pivotally support links 4S and 50 of the second arm assembly 14. If desired these plates 46, the pins 36 and the adjacent portions of the links 48 and 50 can be considered as constituting the end 2S.

The connecting joint 16 is constructed so as to include what may be referred-to as a frame 52. This frame 52 includes two parallel plates 54 held relative to one another through the use of bolts 56, 58, 60 and 62 and through the use of sleeves 64 serving both as spacers and as pivots. Illest sleeves 64 are located around the bolts 56, 55, 60 and 62 as shown in Fig. 4 and are "sandwiched" between the plates 54. It will be noted that the bolt 56 is associated with tile link 38; tliat the bolt 58 is associated with the link 40; that the bolt 60 is associated nv,th the link 48; and that the bolt 62 is associated with the link 50.

Bccause of this construction, if desired, all of the bolts 56, 58, 60 and 62 can be referred to as pivots since they pivotally support the various links indicated. With this construction it can be considered that the end 18 of the arm assembly 12 is constituted by the bolts 56 and 58, those portions of the plates 54 connecting them and the adjacent portions (not separately numbered) of the links 38 and 40. Similarly it can be considered that the end 20 of the arm assembly 14 is constituted by the bolts 60 and 62, those portions of the p]ates 54 connecting them and the adjacent portions (not separately numbered) of the links 48 and 50.

The joint 16 also preferably includes a sector plate 66 attached to the link 38 by rivets 68 so as to rotate therewith. Another corresponding sector plate 70 is attached to the link 43 . t corresponding rivets 68 so as to also rotate therewith. The piate 66 is provided with an arcuate slot 72 which is centered about the bolt 56; the plate 70 is provided with a correr.ponding arcuate slot 74 which is centered about the bolt 60. Although these twe sector praies 66 and 68 are spaced from one another so as to lie generally alongside of the plates 54 they overlap as shown in Fig. 4 in such a manner that these slots 72 and 74 overlap one another as shown.

This construction enables a bolt 76 to be used in securing the plates 66 and 70 against relative movement This bolt 76 is constructed so as to include a head 78 positioned within an enlarged opening 80 in one of the plates 54 and a shank 82 threaded into an intermally threaded insert 84 within a handle or knob 86. This insert 84 extends through a corrsponding opening 80 in the other plate 54 so that it can bear directly against the plate 65 in order to clamp against a slceve 88. Tllis slceve 88 is located around the bilt 76 between the. two plates 66 and 70.

In order to bind various functional parts of the joint 16 as described in the preceding it is possible to include as a part of this joint 16 two shell like covers 90 which are capable of being snapped or otherwise connected together so as to rest on or be carricd by the plates 54. If dcsired an enlarged secondary head 92 can be located on the bolt 76 for appearance purposes. The covers 90 are not only desirable for appearance reasons. They serve to avoid an possibility of fingers being inserted into the parts described which are located generally between these covers 90.

Tabs 94 on these covers 90 are preferably used to hold other coil springs 96 so that these springs 96 extend between the joint.l6 and a tab 97 on the link 48 as shown in what can be regarded as a conventional manner. Only one of these tabs 94 and of the springs 96 are shown; the others are underneath them in Fig. 1 and, hence, are not visible.

Of course if desired various functional equivalents can be slubstituted for the springs 96.

It is considered that the use ofthe complete adjustable arm structure 10 w.il reasonably self evident from tile preceding. When the knob 86 is loose it is possible to move and position the arm assemblies 12 and 14 so that they extend at any desired angle relative to one another and to the various joints 16, 22 and 26. During such movement the plates 66 and 70 will move relative to one another because of the construction employed.

When they are positioned as desired the entire structure 10 can be "locked up" by tightening the knob 85.

By virtue of the constructional details employed even when the knob 86 is only moderately lightened the entire structure will be capable of supporting relatively l^avy items such as the item 30 indicated in tile preceding. This is con..idered to be quite important It is considered to be primarily related to the use of the overlapping sector plates 66 and 70 cooperating so that the single bolt 76 is located so as to be capable of clamping them together at a location which is a significant distance from the bolts 56, 58; 60 and 62.

The latter serve as pivots for the various links indicated. If desired a single bolt (not shown) can be used in place of the t'vo bolts 56 and 60 so that both sector plates 66 and 70 used are mounted on a common axis in obtaining the action indicated in this discussion.

This is not normally desired because it necessitates a side by side location of parts on a single pivot . Such a structure is considered to be undesirably bulky compared to the described structure in which all links employed are scparately mounted into or in the joint 16.

Claims (8)

We claim:

1. An adjustable arm structure which includes first and second elongated arm assemblies located relative to one another so as to have adjacent ends and remote ends, connecting joint means connecting the adjacent ends of said assemblies, a mounting joint means for use in mounting said structure located at the remote end of said first arm, a holding joint means for supporting an item located at the remote end of said second arm, each of said arm assemblies including first and second parallel links, said links of said first arm assembly being pivotally connected to mounting joint means and said connecting join means, said links of said second aim assembly being pivotally connected to said holding joint means and said connecting joint means, in which the improvement comprises: said connecting joint means including frame means, said links of said arm assemblies being pivotally connected to said frame means, said connecting joint means also including a first sector plate attached to a link of said first arm assembly and a second sector plate attached to a link of said second arm assembly, said set -or pates extending parallel to one another, said connecting joint means also including securing means extending between said sector,plates for securing said sector plates against movement relative to one another so as to hold said arm assemblies against movement changing the distance between the links in said arm assemblies.

2. An adjustable arm structure as claimed in claim 1 wherein: said securing means includes a bolt for use in clamping said sector plates against movement and handle means for use in tightening and loosening said bolt.

3. An adjustable arm structure as claimed in claim 2 wilerei;l: said sector plates include overlapping slots and said bolt extends through said s1ots.

4. An adjustabl \ arm structure as claimed in claim 3 wherein: said slots are arcuate slots each of which is centered around the pivotal connecting of the link on which it is located to said connecting joint.

5. An adjustable arm structure as claimed in claim wherein said pivotal connections of said links upon which said sector plates are located to said connecting joint are spaced from one another.

6. An adjustable arm structure as claimed in claim 1 wheicin: said securing meons includes a bolt for use in clamping said sector plates against moveTmnrt and handle means for use in tightening and Icosening said bolt, said sector plates includ overlapping slots and said bolt extends through said slots,:: said slots are arcuate slots each of which i centered around the pivotal connection of the link on which it is located to said connnecting joint, said pivOtal connections of sad links up n which said sector plates are located to said connecting joint are spaced from one another and said connecting,,oint means also includes cover means covering said sector plates and the pivotal connections between said links and said connecting joint means.

7. An adjustable arm structure comprisin articulated first and second limbs each comprising a pair of parallel members one of which is coupled to a respective sector plate at the articulated joint between the two limbs, and the sector plates being movably coupled relative to each other and being releasably lockable with respect to each other.

8. An adjustable arm structure substantially as herein described with reference to the accompanying drawings.