GB2220307A - "Articulated support for a lamp or the like" - Google Patents

Abstract

An electrical connection between two parts 12, 14 of a support arm of an electric lamp on either side of an articulated joint in said arm is effected by means of conductors 20, 34 forming part of the joint. In the preferred embodiment two metal plates 20, fixed in mutually insulated manner in a sub-assembly 22 carried by one arm part 12, are pivotally connected with a sub-assembly 24 carried by the other arm part 14, through an insulated pivot arrangement 30, 42 provided by the sub-assembly 24. Contact plates 34 carried by the sub-assembly 24 make sliding electrical contact with the respective plates 20 and are connected with the bulb socket of the lamp by conductors extending within the arm part 14. The plates 20 are likewise connected to a source of power by conductors 50 extending internally within the arm part 12. The components of the joint are held together by screws 46 or posts mounted in apertures through hinge blocks 30, 30'. The latter can support partitions for separating the electrical wires (see figure 5) or rubber inserts (see figure 6) that increase the friction in the joint. <IMAGE>

Description

DESCRIPTION OF INVENTION Title: "Articulated support for a lamp or the like" THIS INVENTION relates to an articulated support for an electrically powered device, for example for a spot-lamp.

It is an object of the invention to provide such an articulated support in which the pivoting of the respective articulation does not involve the bending or flexing of electrical conductors.

According to the invention, there is provided an articulated support for an electrically powered device, wherein an electrical connection, for the supply of electricity to such a device, is established between cooperating electrically conductive members in the region of at least one articulation of the support and which members make rotational or sliding electrical contact with one another during flexing or pivotal movement of the articulation.

An embodiment of the invention is described below by way of example with reference to the accompanying drawings, wherein: FIGURE 1 is a perspective view showing an adjustable spot lamp including an articulated support embodying the invention, FIGURE 2 is a fragmentary side elevation view of an articulated joint of the lamp support of Figure 1, to a larger scale, FIGURE 3 is a view partly in vertical section and partly in front elevation of the joint of Figure 2, FIGURE 4 is a fragmentary exploded perspective view of part of the joint of Figures 2 and 3; FIGURE 5 is a perspective view showing a variant hinge block for a joint in an articulated support embodying the invention, and FIGURE 6 is a perspective view showing a further variant hinge block.

Figure 1 illustrates an adjustable spot lamp embodying the invention and comprising a base 10, a standard 12 extending from the base 10, an arm connected with the end of standard 12 remote from base 10 by means of a joint 16 permitting pivotal adjustment of the arm 14 relative to the standard 12, the arm 14 carrying at its end remote from the joint 16 a conventional lamp and shade arrangement 18.

The invention resides principally in the features of the joint 16, described in detail below. In other respects, the lamp is a conventional electric lamp, although, in the preferred embodiment described below in which the lamp assembly includes exposed conductors, the lamp to be described is intended to be used with an extra low voltage power supply.

The standard 12 and arm 14 comprise, over the major parts of their length, respective lengths of tubing, with the joint structure 16 affording respective parts which plug into the adjoining ends of the respective lengths of tubing as will appear below.

Referring to Figures 2 and 3, in which the joint 16 is shown to a larger scale, the joint comprises two parallel flat metal hinge plates 20, which are fixed in and project from a sub-assembly 22 forming the upper end of the standard 12 in Figure 1 and on which plates 20 an upper sub-assembly 24, forming the lower end of the arm 14 in Figure 1, is pivotally mounted. The hinge plates 20 form respective parts of the electrical circuit whereby electricity is supplied to the lamp in the lamp assembly 18.

The sub-assembly 24 comprises complementary outer shell members 26 and 28, of plastics, between which is sandwiched a plastics hinge block 30. The shell members 26 and 28 have upper portions which form a plug which is inserted into the lower end of the tubular part of the arm 14. The hinge block 30 is centred on the longitudinal axis of the arm 14 and has opposite planar side faces, parallel with one another and with the longitudinal axis of the arm 14, which axis extends midway between the flat faces of the hinge block 30. Lying against each of the side faces of the block 30 is a respective conductor plate 34 of beryllium copper, phosphor bronze or copper plated carbon spring steel.The hinge block 30 has a cylindrical bore 38 extending transversely therethrough, perpendicularly with respect to the flat side faces of the block and the conductor plates 34 have registering circular apertures therethrough so that the lower portions of the plates 34 are in the form of rings.

The assembly comprising the hinge block 30 sandwiched between the plates 34 is in turn sandwiched between the upper portions of the hinge plates 20 which extend parallel with and on either side of the longitudinal axis of the standard 12. The upper portions of the hinge plates 20 have circular apertures 200 (Figure 4) therethrough which register with the apertures in the plates 34 and the bore 38 in hinge block 30. Cylindrical bosses 42 project transversely from the inner sides of members 26 and 28, through the holes in the respective plates 20, 34 and into the bore 38 from opposite ends thereof.

A clamping screw 46 extends through aligned bores in the members 26 and 28, extending axially through the bosses 42 and serves to hold the members 26 and 28 together and to clamp the plates 20, 34 and hinge block 30 firmly therebetween. The members 26, 28, have planar inner faces 94, (Figure 4) which engage the outwardly presented planar faces of the upper portions of plates 20. The assembly comprising members 26, 28, hinge block 30 and plates 34 may thus pivot relative to the plates 20, and thus relative to the standard 12, about the axis of the pivot provided by stubs 42 and the bearing, for said pivot, afforded by the circular holes through the upper ends of the plates 20.

The configuration of the lower sub-assembly 22 is similar to that of the assembly 24, but because of the configuration of the lower part of the plates 20, the latter are held firm in the sub-assembly 22 rather than being pivotal therein. Thus, the sub-assembly 22 comprises outer shell members 26' and 28', lower portions of which form a plug which is inserted in the upper end of the tubular part of the standard 12, a block 30' similar in configuration to the block 30, (but corresponding in thickness to the combined thickness of the block 30 and plates 34), the block 30' being sandwiched between intermediate portions of the plates 20, with the assembly comprising the block 30' and the plates 20 being in turn sandwiched between upper portions of the shells 26' and 28'.As in the case of the upper sub-assembly 24, the shell members 26', 28' have internal bosses 42 which pass transversely through corresponding apertures 208 in the intermediate portions of the plates 20 and into the transverse bore through the block 30'. The two shell parts 26', 28' are, like the part 26, 28, held together by a transverse clamping screw (not shown) received in the transverse bores through the internal bosses 42 which extend through the apertures 208 in the intermediate portions of the plates 20.

The shell members 26 and 26' are also identical with each other and are identical with members 28, 28', except that in the members 28, 28' the bore extending through the boss 42 is appropriately undersized with respect to the shank of the transverse clamping screw which is of the self-tapping kind), whereas in the members 26, 26' the bore extending through the boss 42 is wide enough to accommodate the shank of the respective clamping screw 46 as a free fit and the outer end of the bore is countersunk to receive the countersink head of the screw 46.Referring to Figures 2 to 4, each shell member 26, 26', 28, 28' comprises a wider portion 80 which, over the major part of its length, is externally semi-cylindrical and a narrower portion 82 which is semicylindrical over its entire length, the cylindrical surface of the portions 80 and 82 having a common axis of curvature which corresponds with the longitudinal axis of the respective standard 12 or arm 14 in the assembled fitting, the narrower portion 82 extending axially from the wider portion 80 so that a half-annular shoulder is defined at the junction between the adjacent ends of the outer surfaces of the portions 80 and 82. A co-axial semi-cylindrical channel 86 extends along the narrower portion 82 on the inner side thereof and a rectangularsection channel 88, communicating with the channel 86, extends axially over the major part of the wider portion 80. On their inner faces, the parts 80 and 82 terminate in co-planar faces 90, 92 respectively lying in a diametrical plane which includes the longitudinal axis of the respective sub-assembly 22, 24. Adjacent its free end, each shell is recessed on its inner side, to provide a planar surface 94, parallel with the surfaces 90 and 92 but co-planar with the bottom of the channel 88 and thus set back with respect to the surfaces 90 and 92 relative to the axis, for engagement with the outer surfaces of the plates 20 or 34. On the inner side of each shell member, the respective boss 42 projects, from the surface 94, towards the plane of the surfaces 90, 92 and terminates just short of the latter plane.It will be appreciated that, in the assembled joint, the two cooperating shell members of each sub-assembly 22, 24 define, by their respective parts 82, a cylindrical tubular spigot for insertion into the bore of the respective length of tubing, whilst the rectangularsection channels 88 provide locating recesses for rectangular tongues 206 of the plates 20 or rectangular tongues 208 of the plates 34 and for a root portion 98 of the hinge block 30, 30'. Insulated electrical wires, indicated in dotted lines at 50 in Figure 3, extend from the base 10 within the tubular part of standard 12 and through the bore formed by cooperating channels 86 in the members 26', 28', to the space defined by channels 88 within the lower sub-assembly 22, where they are soldered or otherwise conductively secured to the lower ends, within the sub-assembly 22, of tongues 206 of the respective hinge plates 20.In a similar manner respective insulated wires are soldered to the upper ends of plates 34, within the upper sub-assembly 24, said wires leading through the interior of the tubular part of the arm 14 to the lamp fitting in conventional manner for the supply of electricity to the lamp fitting. As the parts of the sub-assembly 22 in contact with the plates 20 are of electrically insulating material, as are the hinge blocks 30 and members 26 and 28, the hinge plates 20 are electrically insulated from one another. In the same manner, the plates 34 are electrically insulated from one another allowing the supply of electricity to the lamp fitting through the wires 50, hinge plates 20, conductor plates 34 etc.As shown in Figure 4, the lower annular end portions of the plates 34 are deformed into a "wavy" configuration, so that these portions act as spring washers which are compressed by tightening of the upper screw 46 so that a firm pressure, ensuring reliable electrical contact, and good frictional retention of the adjusted angle of the joint 16, is maintained between the plate 34 and the plate 20.

In a variant illustrated in Figure 5, each hinge block 30, 30' has, projecting axially from its stem 98, an integral partition plate 100, which serves to ensure separation and appropriate insulation. between the tongues of the plates 20, 34 and the bared ends of the wires, such as wires 50, soldered thereto. The partition 100 may be a relatively thin member extending diagonally with respect to the stem 98 and thus, in the assembled fitting, extending diagonally with respect to the rectangular-section passage formed by the two channels 88 of the members 26, 28 in combination, thereby affording as much room as possible for the round-section conductors 50.

Whilst the frictional force acting between the plates 20 and 34 is sufficient, in many applications, to retain the arm 14 and standard 12 in a desired adjusted angular relationship without other retaining means, if desired, the hinge block 30', as shown in Figure 6, may be provided with an axially-located recess at the end of the hinge block which forms the free end of the respective assembly 22, 24 and which recess receives, in a compressed condition, a rubber insert 105 which bears frictionally upon the opposing surface of the hinge block 30.

In the block of Figure 6, the central recess receiving insert 105 is formed as a rectangular notch extending transversely from one flat face to the opposite flat face of the hinge block and the rubber insert 105 is in the form of a complementary block. It will be appreciated that the transverse notch 105 will be closed at its opposite ends, in the assembled joint, by the adjoining plates 20.

The variant hinge block shown in Figure 6 is additionally provided with laterally projecting cylindrical bosses 142 on either side thereof. This hinge block is intended for use with shell members which differ from those illustrated in Figures 2 to 4 by having, instead of the bosses 42 projecting from the surfaces 94, cylindrical recesses in the surfaces 94 to receive the bosses 142 so that, in this variant, the bosses 142 on the hinge block extend through the aligned apertures in the plates 20 or the plates 34 and into these recesses.

In this variant arrangement, the clamping screw 46 and the bores to receive the same may be omitted, and the sub-assembly held together merely by the clamping effect of the adjacent tubular member into which the narrower ends of the shell members are inserted. In the preferred embodiment, the lower sub-assembly is of this variant type, with only the upper assembly being retained by a clamping screw 46. Alternatively, both sub-assemblies in the joint may be of this variant type, (with only one of the hinge blocks 30, 30' being recessed to receive a friction insert) provided that the design is such that the plates 20 are reliably maintained in good electrical contact with the plates 34.

It will be appreciated, of course, that in further variants, the insert 105 and recess receiving the same may be omitted, or that such recess with an insert 105 may be provided in the block 30' of Figures 2 to 4 or of Figure 5.

However, it is preferred to use screws 46 for the sub-assembly which forms the pivot, to ensure that the thermoplastics does not "creep", to allow the frictional torque developed by the joint to be adjusted to carry various loads at the end of arm 14 and to allow adjustment for wear in the frictionally engaging faces in use.

It will be appreciated that, if desired, the shell members, instead of being adapted to be inserted in the end of a tubular member affording the major part of the respective standard or arm 14, may be substantially elongate members adapted, in cooperation with one another, to define the entirety of the respective standard 12 or arm 14.

The shell members and the hinge blocks are preferably made of a strong, insulating plastics material, such as 30% glass reinforced polycarbonate. The hinge plates 20 are conveniently of bright nickel plated brass.

In the preferred embodiment, the parts of the hinge plates 20 which lie against the faces 94 are of such width that the outer edges of these parts extend to, and form part of the outer surface of the fitting and additionally serve an aesthetic function. In this embodiment, the lamp is intended for use with an extra low voltage power supply so that exposure of the currentcarrying hinge plates 20 presents no danger. The construction envisaged allows the standard 12, joint 16 and arm 14 to be made very slender, for example less than 10 mm in diameter, and is particularly suitable for a miniature spotlight.

It will be understood that whilst, for ease of description, it has been assumed in the foregoing that the base 10 is lowermost, with the standard 12 extending upwardly from the base and the arm 14 extending upwardly from the standard 12, the invention is not limited to any particular orientation, and, indeed, the base 10 is just as likely, in practice, to be fixed to a wall, with the standard 12 extending horizontally, or to a ceiling with the standard 12 extending vertically downwards from "base" 10 to joint 16.

Similarly, whilst, in the preferred embodiment, the hinge plates 20 are carried by the joint sub-assembly on the standard 12 and the plates 34 by the joint subassembly on the arm 14, this arrangement could be reversed without difficulty.

Claims (6)

1. An articulated support for an electrically powered device, wherein an electrical connection, for the supply of electricity to such a device, is established between cooperating electrically conductive members in the region of at least one articulation of the support and which members make rotational or sliding electrical contact with one another during flexing or pivotal movement of the articulation.

2. An articulated support according to claim 1, wherein at least one of said electrically conductive members forms a mechanical load--supporting component of the respective articulation.

3. A lamp fitting incorporating an electric lamp supported by an articulated support according to claim 1 and electrical conductors for the supply of electricity to the lamp through said articulation of the support.

4. An articulated support for an electrically powered device, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

5. A lamp fitting substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

6. Any novel feature or combination of features described herein.