EP0033287B1 - Security fitting for a tubular lamp with axial end caps - Google Patents

Abstract

1. A safety socket for a tubular lamp having axially opposed bases, comprising elastic means (13) disposed between one base (21) of the lamp and a mount (14), these means being adapted to maintain the lamp by a clamping action exerted axially against the bases, and means (12, 36) capable of being connected to an electric supply circuit, characterized in that the safety socket comprises a cap (9) comprising two parts (10, 11) assembled together by telescopic mounting, hereinafter called for convenience sake casing (10) and sleeve (11) ; the said casing (10) being removably interfitted on a mount (14), the said cap accommodating elastic means, whilst means (12, 36) associated with the cap (9) and the mount (14) are adapted to establish an electrical connection with a supply circuit.

Description

The present invention relates to sockets intended to support and energize, a tubular lamp with axial caps, of the incandescent type.

Known sockets of the above kind arranged to exert an axial thrust on the lamp bases so that the latter is held by pinching between the sockets; in general, the means exerting such a clamping effect are constituted by springs simultaneously ensuring an electrical connection with a supply circuit.

Patent US-A 2,447,676 (Bryant Electric Company) issued on August 24, 1948 teaches a socket comprising a hollow monobloc support with an opening forming an end-of-travel stop at an insulating piston plate. A spring arranged in the hollow support has the function of pressing on an inner face of the piston plate a contact disc placed opposite an opening formed in the piston plate for the passage of a lamp contact; the spring also has another function which is to establish an electrical connection with a contact blade.

Such a socket does not solve the problems posed now with great rigor regarding safety.

In fact, when handling the lamp, one end of the lamp is first engaged in a support, then after compression of the spring, the other end can be engaged in another support suitably spaced from the previous one.

Now during these manipulations, after one end of the lamp has been engaged in a support, the other end is widely accessible to the operator, so that there is a risk that the latter constitutes a current supply, whence results considerable risks of serious accidents, even fatal.

Patent US-A 2656521 (Silvania Electric Products) issued on October 20, 1953 teaches a support for fluorescent tube, whose provisions are very similar to US-A 2,447,676 with the difference that the contact piece - whose role is similar to that of the piston plate of the aforementioned patent - is here, protruding with respect to the hollow cylindrical element.

We therefore make, overall, the same remarks as above with regard to the safety of the person having to handle a lamp to associate it, or remove it from such a support.

It follows from the provisions mentioned above that the configuration of the sockets, leaves within the reach of the operator's hands elements which may be under electric voltage when handling the lamp.

The present invention relates to a socket of simple production, and whose configuration prevents the operator from having access to the lamp bases, as well as to the electric current supply pads, so that the operator can act safely even if the electric current supplies are live.

A safety socket for a tubular lamp with axial caps, comprising elastic means disposed between the lamp base and a base, these means being adapted to hold the lamp by a pinching effect exerted axially on the caps, as well as suitable means to be connected to an electrical supply circuit, is characterized in that it comprises a cap comprising two parts assembled by telescopic mounting, hereinafter called for convenience case and sleeve, said case being provided removably nestable in a base , said cap housing elastic means, while means associated with both the cap and the base are adapted to establish an electrical connection with a supply circuit.

Safety is obtained, with such a socket, from the fact that the lamp caps during handling are completely masked by the caps, hence inaccessibility to the caps, and also by the fact that the electrical connection of the lamp with the circuit d 'power is only established at the end of fitting the caps in the bases, so that in no case the contact elements associated with each cap, can not be placed under electric voltage as long as they are accessible by the operator.

Such a socket, in addition to its simplicity of construction, therefore of a low cost price, therefore offers the required security guarantees.

• fig. 1 est une vue en perspective éclatée d'une douille de sécurité selon la présente invention, illustrant respectivement les deux parties du capuchon (manchon et boîtier) et le socle; la
• fig. 2 est une vue en élévation longitudinale d'une lampe dont chaque culot est équipé d'une douille de sécurité selon l'invention, lesdites douilles étant montrées en coupe; la
• fig. est une vue en élévation d'une lampe tubulaire à culots axiaux, dont les culots sont- équipés chacun d'un capuchon, la lampe ainsi équipée étant montrée avant mise en place dans les socles; la
• fig. 4 illustre, en élévation et schématiquement, une phase de mise en place, ou d'extraction, d'une lampe équipée de ses capuchons, dans les socles eux-mêmes fixés sur un support quelconque; la
• fig. 5 est une vue en coupe à échelle agrandie de la zone entourée à la fig. 4 et indiquée par V; la
• fig.6 est une vue analogue à la fig.4 d'une variante de mise en place ou d'extraction d'une lampe équipée de ses capuchons dans les socles; la
• fig. 7 est une vue à plus grande échelle de la partie entourée à la fig. 6, et indiquée par Vll; la
• fig. 8 est une vue en perspective de la partie indiquée par VIII à la fig. 5 montrant en particulier l'articulation du capuchon sur le socle.

Other characteristics and advantages of the invention will also emerge from the description which follows, given by way of example with reference to the appended drawings in which the

• fig. 1 is an exploded perspective view of a safety socket according to the present invention, respectively illustrating the two parts of the cap (sleeve and housing) and the base; the
• fig. 2 is a longitudinal elevation view of a lamp, each base of which is fitted with a safety socket according to the invention, said sockets being shown in section; the
• fig. is an elevational view of a tubular lamp with axial caps, the caps of which are each equipped with a cap, the lamp thus equipped being shown before being placed in the bases; the
• fig. 4 illustrates, in elevation and schematically, a phase of placing, or extracting, a lamp equipped with its caps, in the bases themselves fixed on any support; the
• fig. 5 is a sectional view on an enlarged scale of the area surrounded in FIG. 4 and indicated by V; the
• fig.6 is a view similar to fig.4 of a variant of fitting or extracting a lamp equipped with its caps in the bases; the
• fig. 7 is an enlarged view of the part surrounded in fig. 6, and indicated by Vll; the
• fig. 8 is a perspective view of the part indicated by VIII in FIG. 5 showing in particular the articulation of the cap on the base.

According to the embodiment chosen and shown in the figures, in particular in FIG. 1, a safety socket according to the invention comprises a cap indicated generally at 9 comprising a first part 10 forming a housing with a second part 11 forming a sleeve, these two parts being assembled by telescopic mounting and at spacing by elastic means constituted by the occurrence by a spacer spring 13; the socket also includes a base 14 intended to be fixed to any support schematically shown in 15.

The sleeve 11 of the cap has in the exemplary embodiment shown, without limitation, a generally tubular shape with quadrangular section with open ends and it is adapted to be engaged in the housing 10 without significant play; the sleeve 11 advantageously comprises on its inner faces of the longitudinal ribs 20 serving to guide the base 21 of the lamp 22, it will be noted that this part of the cap could be devoid of such ribs so that this part 11, depending on whether it has ribs or not, can receive a lamp with bases of different diameters.

The ribs 20 extend locally inside the sleeve 11 by having a truncated end 20A, intended to form a stop for the lamp 22.

On the opposite side where the sleeve 11 receives the lamp, this sleeve has, on each side, a notch 25 intended to form recesses to allow the insertion of the spring 13 inside said sleeve 11, so that a end of this spacer spring 13 rests on the bottoms 25A of the notches 25.

On one side, the sleeve 11 has a longitudinal opening 26, the usefulness of which will appear later.

As for the housing 10 of the cap, it has the appearance of a tubular element closed at one end by a bottom 28, the other end being open to allow engagement of the sleeve 11.

The housing 10 has a lower face or base 29, and an upper face 30; in the lower face is made a hole 31, while the upper face has projecting sides and a gripping means 32 intended to be projecting relative to the base 14; it will be noted that the aforementioned gripping means is located between two support planes 33, 34, (see also fig. 8) whose usefulness will appear later. Significantly in the angle formed by the bottom 28 and the base 29, a longitudinal slot 35 is provided to allow the passage of a first electrical connection element indicated generally at 36.

Such a first electrical connection element is in the form of a blade 36 having a flat section 36A extended by a heel 36B with a return 36C; the planar section 36A being intended to be pressed by the aforementioned spring 13, on the bottom 28 of the housing 10, while the heel 36B is shaped to project from the outside face of this bottom 28.

When the sleeve 11 is engaged in the housing 10, after the first contact element 36, the spacer spring 13, and an element capable of establishing an electrical connection between the end face of the lamp base and the aforementioned first contact element, such an element being, in the example shown constituted by a spring 12 coaxial with the spacer spring 13, the sleeve 11 is assembled by a sliding assembly to the housing 10 to form the cap 9; for this purpose, a rivet 40 is placed in the hole 31, the rod 40A of which is adapted to cooperate with the longitudinal slot 26 formed in the sleeve 11.

There is thus produced an assembly forming the cap 9 in which the sleeve and the housing are telescopically mounted, the various elements being captive, and the sleeve 11 being kept apart from the housing 10 by the spacer spring 13.

The cap 9 thus formed is intended to be associated with a lamp base, (for the sleeve 11 of the cap) and in the base 14 (by the housing 10 of the cap); this base comprises a base 50 with holes for fixing 52 to a support, which base is bordered by sides extending vertically respectively lateral 53, 54, and bottom 55.

In the angle formed by the base 50 and the vertical bottom side 55 comprising an external boss 56, there is formed in the latter, but inside the base, a cavity 57 adapted to receive a second contact element constituted by a pad 58; the bottom of this cavity has a hole 59 provided to allow the passage of a conductor 80.

It will be noted with regard to the abovementioned housing that it allows the pad 58 to be set back relative to the inner surface of the bottom wall 55 of the base, so that this pad is practically not accessible.

The cavity 57 is able to allow the setting of the pad 58 which comprises a screw 58A accessible from the inside of the base, this screw ensuring the connection of the conductor 80 to said pad 58.

It is noted that the screw 58A is not projecting relative to the pad 58.

The bottom side 55 has at its free upper edge a central notch 65 on either side of which ears 66, 67 are respectively formed.

In fig. 2, each base 21 of a lamp 22, is equipped with a cap 9, as described above, and the caps are each engaged in a base 14 fixed to any support, such as a strip 15, this the latter is however not essential, the bases 14 can be fixed directly on a support.

In this figure we see that each contact pad 58 is connected with a conductor 80 connected to an electrical supply circuit, and that the electrical connection between these contact pads and the corresponding caps 21 of the lamp 22 is ensured through the blade 36 and the preferably conical contact spring 12, while the spacer springs 13 ensure the maintenance of the lamp by axial pinching because these are compressed when the caps 9 are inserted inside the bases 14.

In fig. 3, it can clearly be seen that the lamp 22, the caps of which are fitted with caps 9, has a total length L clearly greater than the dimension L ′ comprised between the two bases 14.

It will be noted that such an arrangement not only ensures that the lamp 22 is maintained between the bases 14, but also allows good contact between the lamp bases and the studs 58.

In addition, the sleeves 11, housing 10, and base 14, being made of insulating moldable material, the bases 21 of the lamp are protected, at the same time as they are inaccessible to the operator, given that they are capped in their entirety by said caps.

With regard to placing in a suitably spaced bases a lamp whose bases are fitted with caps as above, two possibilities are offered to the operator.

According to a first possibility (FIGS. 6 and 7), the lamp 22 is engaged from the front between the bases.

To do this, the operator exerts an axial pressure (arrows F) on each cap 9 so as to reduce, by compression of the spring 13, the length L to a length less than that L 'comprised between the bases, which has for simultaneous effect of bringing the free ends of the contact springs 12 to the end face of the caps 21; that said, the lamp can easily be engaged between the bases until the lower faces 29 of the housings 10 come into abutment on the bases 50 of the bases 14.

The pressure can be released if this has not been done during insertion, the release of the pressure on the housings 10 of the caps having the effect of releasing the spacer springs 13 and ensuring contact of the heels 36B with the studs 58. Simultaneously the lamp is held between the bases 14 under the effect of the spacer springs 13. Note that the heels 36B are applied to the studs 58 by the action of the spacer springs 13, thereby establishing the electrical connection, and this, at the very end of fitting the caps into the bases.

It is noted that as soon as the beginning of the insertion of the lamp between the bases 14, the operator no longer has any possibility of access to the elements that may be under electric voltage; as also the lamp bases are fully protected, total security is achieved and the same applies when the lamp must be removed from the bases because, conversely to the above, the electrical connection between caps and bases is interrupted from the start of the extraction of the lamp from the bases.

According to another possibility illustrated in FIGS. 4 and 5, the lamp is tilted around a pivot axis XX (see also fig. 8) formed by the cooperation of the support planes 33, 34, formed in the housing 10 of the cap, with the edges free ears 66, 67, formed in the base.

To do this (fig. 5 in particular) the lamp is presented inclined with respect to the bases 14 and any of the caps are inserted into a base; a push is then exerted (arrow F1) on the free cap at the same time as it is inserted into its corresponding base; we note that the heels 36B thus inserted provide no electrical connection with the circuit as long as the caps 9 are not brought into abutment in their respective bases.

According to this way of doing things, total security is also obtained in particular because the operator has at no time a possibility of access to elements that may be under electric voltage.

It will be noted (FIG. 2 in particular) that a clearance J is formed between the bottom wall 28 of the housing 10 of the cap and the bottom side 55 of the base; such a clearance being obtained by the cooperation of the heel 36B with the stud 58 so that one is assured of a good electrical connection at the contacts.

It therefore follows that the manipulations of a tubular lamp with axial bases fitted with sockets according to the invention can be carried out without causing any danger to the operator.

Indeed if the operator introduces the lamp 22 obliquely in the bases 14, that is to say one end first then, the other end then (case of fig. 4 and 5 of the drawings) we see that the electrical connection between the blade 36 and the stud (58) is effective only at the end of nesting, that is to say when the two caps are fitted in their respective bases. so that during all the time that the lamp lasts, the blade 36 of the cap fitted to the non-nested end of the lamp in its socket, can in no case be put under electric voltage.

It is the same in the case of FIG. 6, for which, from the start of the engagement of the caps in the bases, no electrical contact element is accessible to the operator.

Conversely, when the lamp must be removed from the sockets, for example for its replacement, the electrical connection pad 58, blade 36 is cut at each end of the lamp at the start of the operation, so that there is no risk for the operator if the latter were to touch the contact elements 36 during operation, which is almost impossible, in particular due to the location of said contact elements.

It should also be noted that the pad 58 is confined in a cavity while being set back with respect to the internal face of the bottom side 25 of the base so that this pad is also almost inaccessible even when the cap 9 is removed.

Of course, the invention is not limited to the embodiment chosen and shown, which is on the contrary subject to modifications without departing from the scope of the invention, this is how the contact elements could have a configuration. different and be arranged in another location, which will in any event be as distant as possible from the hinge axis XX, the pad 58 being provided set back from a cavity which receives it. Similarly, it is understood that the cap and the base could have a different section from that shown, for example circular or other, without the general provisions of the parties in question being significantly modified.

Claims (14)

1. A safety socket for a tubular lamp having axially opposed bases, comprising elastic means (13) disposed between one base (21) of the lamp and a mount (14), these means being adapted to maintain the lamp by a clamping action exerted axially against the bases, and means (12,36) capable of being connected to an electric supply circuit, characterized in that the safety socket comprises a cap (9) comprising two parts (10, 11) assembled together by telescopic mounting, hereinafter called for convenience sake casing (10) and sleeve (11); the said casing (10) being removably interfitted on a mount (14), the said cap accommodating elastic means, whilst means (12, 36) associated with the cap (9) and the mount (14) are adapted to establish an electrical connection with a supply circuit.

2. A safety socket according to claim 1, characterized in that a cap (9) is intended to be engaged on each base of the lamp, the said electrical connection with a supply circuit being established when each cap (9) is fully inserted in its mount (14).

3. A safety socket according to claim 2, characterized in that the sleeve (11) of insulating material is capable of surrounding the base (21) of the lamp and to cooperate, through one end, with a terminal part of the latter, and through its other end with a spacing spring (13) confined in a housing formed between a terminal face of the sleeve (11) and a vertical endwall (28) of the casing.

4. A safety socket according to claim 2 or claim 3, characterized in that the electrical connecting means between a terminal face of the base of the lamp and a supply circuit are constituted by elastically deformable means (12) confined in the aforesaid housing having a heel outside of the casing, this heel being cooperable with a contact element (58) fixed to the mount.

5. A safety socket according to claim 4, characterized in that the aforesaid elastically deformable means is a spring (12) coaxial with and inside the spacing spring (13), this spring having one end cooperable with a terminal face of a base (21) of the lamp (22), and another end cooperable with a blade (36) extending inside the aforesaid housing and having a heel (36B) outside the casing.

6. A safety socket according to any one of claims 2 to 5, characterized in that the sleeve (11) is slidably mounted in the casing (10) between two limit positions, the said sleeve (11) comprising for this purpose a longitudinal slot (26) cooperating with a finger (40, 40A) fixed to the said casing (10).

7. A safety socket according to claim 2, characterized in that the contact element (58) in the mount is a block fixed to the mount (14), this contact block being confined inside a cavity (57) provided in the endwall (55) of the mount, and in the vicinity of the fastening base (50) of the latter, on a support, the cavity being such that the contact block (58) is locked therein and is set back with respect to the inner face of the said vertical endwall (55).

8. A safety socket according to claim 7, characterized in that the contact element (58) fixed to the mount (14) receives a screw ensuring the connection of a lead (80).

9. A safety socket according to claim 7 or claim 8, characterized in that the contact element (58) formes an abutment with the sleeve (10) in a limit position through the medium of a contact blade (16).

10. A safety socket according to claim 7, characterized in that a free upper edge of the vertical endwall (55) of the mount (14) forms a pivot axis (X-X) for the cap (9).

11. A safety socket according to claim 10, characterized in that the aforesaid pivot axis (X-X) is constituted by two lugs (66, 67) situated on either side of a notch (65) formed in the free terminal part of the vertical endwall (55), the said lugs being adapted to cooperate with bearing planes (33, 34) formed on either side of a gripping means (32) extending an upper wall (30) of the casing (10).

12. A safety socket according to any one of claims 2 to 11, characterized in that the sleeve (11) comprises, internally, guide ribs (20) for the base (21) of the lamp (22), the said guide ribs being capable of constituting, through another end for cooperating with a connecting terminal part of the lamp (22) and a base (21).

13. A safety socket according to claim 7, characterized in that the mount (14) comprises on either side of the aforesaid cavity (57) openings (59,60) for the passage of a lead (80).

14. A safety socket according to any one of claims 2 to 13, characterized in that the sleeve has a substantially square cross section as does the casing (10) in which it is at least partially engaged with clearance just sufficient for sliding, whilst the base (14) has a cross section corresponding to that of the casing with an opening into two faces for interfitting with the latter.

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