Patent Grant
10557621
The present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 102018004589.8, filed Jun. 8, 2018, the disclosure of which is hereby incorporated herein by reference in its entirety.
The present invention relates to a socket assembly for receiving a lamp with a pinch seal and a connecting pin led out of said pinch seal for connecting the lamp to a voltage source.
In this regard, socket assemblies are known in which an inner part with a free space for receiving the pinch seal and the connecting pin is rotatably arranged in an essentially cylindrical cavity of an outer housing part. The two parts have slotted openings in their outer surfaces which, when congruent with one another, allow insertion of the pinch seal and the connecting pin into the free space of the inner part from outside. The pinch seal is fixed in the free space by two opposed spring clips which rest against the surfaces of the pinch seal. The lamp is secured in the socket assembly through rotation of the inner part relative to the outer housing part, which causes the slotted openings to shift relative to one another and close. At the same time, an electrical contact is established between the connecting pin, and thus the electric circuit of the lamp, and the voltage source. Such an arrangement is described, for example, in NL 1029855 C.
The known socket assemblies are, however, disadvantageous in that it is oftentimes difficult to securely fix lamps from different manufacturers or lamps with manufacturing tolerances in the region of the pinch seal. For example, the pinch seals of lamps made by different manufacturers differ from one another. The shape of the pinch seal essentially corresponds to an “H” with short parallel struts. However, these struts vary in thickness and height depending on the manufacturer, and in some cases the parallel struts are entirely omitted. The thickness of the planar region of the pinch seal may likewise vary depending on the manufacturer. Moreover, manufacturing tolerances exist in all mentioned regions even for lamps made by one and the same manufacturer. These deviations complicate either the installation of the lamp in the socket assembly or its secure fixation therein. For example, if the distance between the spring clips is reduced or their tension is increased in order to also enable secure fixation of thinner pinch seals, there is a risk that the insertion of lamps having thicker pinch seals into the socket assembly becomes very difficult and the pinch seal might even be broken in the attempt. Conversely, if the distance between the spring clips is increased or their preload is reduced, the lamps are no longer securely fixed in the socket assembly, which may result in failure to reliably establish the electrical contact or in damage to the lamps due to looseness inside the socket assembly.
Accordingly, the object of the present invention is to provide a socket assembly for receiving a lamp with a pinch seal and a connecting pin led out therethrough which avoids the disadvantages described above and also enables secure fixation of lamps having manufacturing tolerances in the region of the pinch seal.
In a first aspect, the present invention thus relates to a socket assembly for receiving a lamp with a pinch seal and a connecting pin led out therethrough, comprising:
an outer housing part with an essentially cylindrical cavity which is accessible from outside via a slotted opening extending in a longitudinal direction of the outer housing part,
an inner part mounted for rotation about a rotation axis inside the outer housing part and including a free space which is configured for receiving the pinch seal and the connecting pin and which is accessible from outside, and
two opposed leaf springs for fixation of the pinch seal in the free space,
wherein each of the leaf springs is bent from a metal strip such that a linear resting face is formed which is adjoined on both sides by leg portions that are angled relative to the resting face and that are adjoined, at their ends distant from the resting face, by base portions running towards one another, said base portions turning into shaft portions that extend away from the resting face, wherein said leaf springs are attached to the inner part in the region of the shaft portions and the resting faces face each other and are essentially parallel to one another.
The basic structure of the socket arrangement according to one embodiment of the present invention thus essentially corresponds to known prior art configurations and likewise has an inner part mounted inside an outer housing part with an essentially cylindrical cavity. In this regard, an essentially cylindrical cavity is to be understood to mean a cavity which allows a rotation of the inner part about a rotation axis which typically extends in the direction of longitudinal extension of the inner part and the direction of longitudinal extension of the lamp. If the lamp includes only one connecting pin for electrically contacting the socket assembly, the rotation axis usually corresponds to the direction of longitudinal extension of the connecting pin. However, the present invention can generally also be applied to lamps with multiple connecting pins. Deviations from the cylindrical shape of the cavity are thus possible as long as they do not affect the described rotation of the inner part inside the outer housing part. The inner part does not need to be able to rotate about 360° inside the outer housing part; instead, a smaller angular range, for example, up to between 90° and 180°, is sufficient. The cavity of the outer housing part is preferably configured such that the inner part can be rotated both clockwise and counter-clockwise.
The inner part is configured to be complementary to the outer housing part such that it can be rotated inside the latter about a rotation axis which typically corresponds to the direction of longitudinal extension of the inner part. It comprises a free space accessible from outside in which the pinch seal and the connecting pin led out of the pinch seal can be received. “Accessible from outside” here means that if the inner part and the outer housing part are arranged in a suitable orientation relative to one another, the pinch seal and the connecting pin can be inserted through the slotted opening of the outer housing part and into the free space of the inner part. The inner part is then advantageously configured such that the slotted opening is closed by the outer wall of the inner part when the inner part is rotated from the position allowing access from outside to a closed position. At the same time, the wall of the outer housing part blocks the access to the free space of the inner part. Furthermore, the socket assembly is preferably configured such that the rotation of the inner part relative to the outer housing part from the open position to a closed position results in an electrical contact between the connecting pin and the current-carrying elements of the socket assembly and eventually the voltage source.
The socket assembly according to one embodiment of the present invention is characterized by a special configuration of the leaf springs used to fix the pinch seal of the lamp in the free space of the inner part. As in the prior art, the leaf springs are arranged opposite one another in the inner part of the socket assembly so as to hold the pinch seal of the lamp between them. Each of the leaf springs is formed from a metal strip, both leaf springs preferably being configured identically so as to clamp the pinch seal of the lamp uniformly from both sides. Thus, the descriptions given below with respect to one leaf spring equally apply to the opposed second leaf spring. The leaf spring is bent from a metal strip such that a linear resting face is formed. This resting face rests against one of the flat surfaces of the pinch seal and exerts a more uniform pressure on a larger surface area of the pinch seal compared to prior art spring clips. The length of the resting face is preferably sized such that it amounts to at least 50%, preferably at least 70%, more preferably at least 80%, and, in particular, at least 90% of the width of the pinch seal (transversely to the direction of longitudinal extension of the lamp). Due to the larger extension of the resting face, the pressure per unit area can be reduced significantly compared to that of a spring clip, so that the local load on the pinch seal, and thus the risk of damaging the same, is minimized.
The resting face of the leaf spring is on both sides adjoined by leg portions that are angled relative to the resting face. The leg portions lead away from the pinch seal and may have a linear or curved progression. The leg portions are in turn adjoined by base portions that run towards one other and may extend either parallel or at an angle to the resting face. The base portions turn into shaft portions which extend away from the resting face and at which the leaf spring is attached to the inner part. The bends of the metal strip in the transition regions between the individual portions of the leaf spring may each be sharp-edged or rounded. The individual portions of the leaf spring and the bends therebetween are preferably configured such that a symmetrical design is obtained, in particular a mirror-symmetrical design with respect to a central plane perpendicular to the rotation axis, i.e., a plane extending through the center of the resting face and between the shaft portions.
The angle between the resting face and each of the leg portions is preferably an obtuse angle, for example, in the range from 110 to 160°, preferably 130 to 150°. Two opposed leaf springs arranged such that their resting faces face one another thus result in a funnel-like access region on each side, said access region narrowing towards the resting faces. This facilitates the insertion of the pinch seal into the region between the resting faces since the leg portions serve as guide faces for the pinch seal and direct the latter towards the gap between the resting faces. Since, as described, a symmetrical configuration of the leaf spring is preferred, an approximately trapezoidal shape is obtained for the head region of the leaf spring, and a mushroom-like contour for the entire leaf spring.
Unlike the prior art spring clips, the leaf springs according to one embodiment of the present invention have a shaft region in which the leaf springs are attached to the inner part. This is preferably done such that the leaf springs are attached to the inner part only in their region of the shaft portion that is distant from the respective resting face, preferably such that their regions projecting over the respective shaft portion are deformable towards the shaft region. More specifically, this means that the projecting regions protrude beyond the adjacent surface of the inner part and are arranged at a distance from the latter that provides for clearance for movement and deformation. This arrangement allows, for example, tilting of the head region of the leaf spring, so that one side of the head region can lean towards the adjacent shaft portion and towards the inner part. This also facilitates the insertion of the pinch seal into the region between the opposed leaf springs. When the pinch seal is inserted with one of its end faces into the gap between the leaf springs, the latter can tilt to back away under the pressure exerted by the pinch seal, so that less force needs to be applied to insert the pinch seal into the gap, and the pressure load on the pinch seal is reduced. At the same time, the distance between the resting faces of the opposed leaf springs can be increased through deformation of each leaf spring. The further the pinch seal is inserted into the gap between the leaf springs the more the latter return to their upright position and expand until finally the resting faces of both compression springs are essentially parallel to one another and bear against the opposite surfaces of the pinch seal. “Essentially parallel” here means that approximately parallel positions, which are, in particular, due to manufacturing tolerances, for example positions in which the opposite surfaces of the pinch seal are not exactly parallel to one another and cause an inclination of the resting faces, are to be encompassed by the present invention. Deviations from parallelism by an angle of up to 3° are in any case encompassed by this definition. However, a parallel orientation of the resting faces of the opposite leaf springs that is as exact as possible is in each case preferred.
Due to the very flexible configuration of the leaf spring and its large resting face, the leaf spring can adapt much better even to differently shaped pinch seals without exerting too much pressure on the pinch seal during the insertion or removal of the lamp from the socket assembly. Nevertheless, the tension with which the leaf springs are preloaded towards one another can still be set high enough to enable even the secure fixation of pinch seals having a small thickness without rendering their insertion and removal too difficult.
The metal strip from which the leaf springs are formed can be closed to obtain a continuous strip. However, this is not mandatory. It is already sufficient and much less complicated to leave the free ends of the metal strip in the finished leaf spring open. The opening between the free ends is preferably located at the shaft region facing away from the resting face, preferably in the outermost bottom region of the leaf spring. The free ends of the shaft portions may be bent towards each other in this configuration. This facilitates the attachment of the leaf spring to the inner part. Generally, any type of attachment may be used. In the context of the present invention, however, it is preferred to attach the leaf spring to the inner part using a slip connection. The end regions of the shaft portions are then particularly preferably slipped into complementary grooves formed in the inner part. The bent ends then prevent the leaf spring from slipping off.
The material used for the metal strip of the leaf springs may generally be any prior art material known to be suitable for manufacturing springs. Metallic materials such as steel and, in particular, spring steel are preferred.
Another improvement according to one embodiment of the present invention relates to the electrical contact between the connecting pin and the socket assembly. As in the prior art, the electrical contact is likewise established and interrupted through rotation of the inner part relative to the outer housing part, which is done in a known manner such that in the open position, in which the pinch seal and the connecting pin of the lamp can be inserted into the free space of the inner part, there is no electrical contact, and said contact is established through rotation of the inner part to a closed position in which the lamp cannot be removed from the socket assembly. According to one embodiment of the present invention, the electrical contact between the socket assembly and the connecting pin is established using a contact spring with an essentially U- or V-shaped body. The contact spring is mounted at a support projection of the outer housing part which protrudes into the free space, and can be connected to an external voltage source. For example, a current-conducting cable may be connected to the contact spring, led out of the outer housing part and coupled to an external voltage source. If the lamp has multiple connecting pins, each is provided with a respective contact, the latter being configured such that an electrical contact is established through rotation to a closed position.
The contacting pin of the lamp bears against a current collector rail thereby forming an electrical contact. In the case of multiple pins, each is provided with a respective current collector rail. For a lamp with one connecting pin, the current collector rail is attached to the inner part such that it comes to rest between the legs of the contact spring, and can rotate with the inner part. The legs of the contact spring and the current collector rail are spaced from one another when the inner part and the outer housing part are in the open position, whereas a contact surface of the current collector rail contacts one of the legs of the contact spring when the inner part and the outer housing part are in a closed position, so that an electrical contact is established between the current collector rail and the contact spring and thus between the voltage source and the connecting pin of the lamp.
The present invention relates not only to the contact spring and/or the current collector rail in combination with the described leaf springs but also to the contact spring and the current collector rail individually, or a combination of leaf springs and contact spring, leaf springs and current collector rail, or contact spring and current collector rail. This also applies to the preferred embodiments of these elements as described below. The materials used for the contact spring and the current collector rail may be the same as for the leaf springs, i.e., metals, in particular steel, preferably high-grade steel or spring steel.
The electrical contact between the contact surface of the current collector rail and the contact spring may be established solely due to the corresponding shaping and arrangement of these parts relative to one another as a result of the rotation of the inner part relative to the outer housing part. In a preferred variant of the present invention, however, the process of establishing the contact is additionally supported by a reduction of the free space in the inner part caused by the rotation of the inner part relative to the outer housing part to a closed position, so that the contact surface and the contact spring are brought closer together. In the same manner, it is also possible to reduce the free space in the region of the leaf springs to increase the pressure exerted on the surfaces of the pinch seal by the resting faces in the closed position. According to one embodiment of the present invention, this is achieved through at least one of the following measures:
a) a circumferential portion of the essentially cylindrical cavity has, at least in regions in the direction of the rotation axis, a diameter which is reduced relative to a circular cross-section;
b) a circumferential portion of the inner part has, at least in regions in the direction of the rotation axis, a diameter which is enlarged relative to a circular cross-section.
Depending on the longitudinal portion, i.e., the region of the cylindrical cavity of the outer housing part and/or the outer circumference of the inner part in the direction of the rotation axis, exhibiting the change in diameter, the reduction of the free space has an effect on either the position of the contact spring and the current collector rail relative to one another and/or the position of the leaf springs relative to one another. The change in diameter may be constant along the entire length or it may be different in the region of the contact spring and the current collector rail compared to the region of the leaf springs. In this manner, it is possible to selectively adjust the reduction of the free space in the closed position for the various regions. For example, the cylindrical cavity of the outer housing part may have a constriction only in the region of the leaf springs, said constriction consisting, for example, in regions that are oblate compared to an otherwise circular cross-section, said oblate regions being located in radially opposed regions that come to rest parallel to the resting faces of the leaf springs in the closed position and thus push the leaf springs towards one another. The same effect can be achieved by enlarging the outer diameter of the inner part in the corresponding regions. The two measures may also be combined. Moreover, the same effect can also be achieved in the described manner in the region of the contact spring.
For the reduction of the free space of the inner part to have a particularly strong effect on the contact spring and its position relative to the current collector spring, a lateral projection is preferably provided on at least one external side of a leg of the contact spring. A sidewall region delimiting the free space rests against this projection when the inner part and the outer housing part are in a closed position and the free space is reduced. The legs are thus pressed against each other, and a contact with the contact surface of the current collector rail is established particularly easily. The external sides of both legs of the contact spring are preferably provided with lateral projections, so that the contact spring is compressed uniformly from both sides upon rotation of the inner part to a closed position. The projection may basically have any shape as long as the intended purpose is achieved. In a preferred variant, projections are created on both sides through a spring ring which is passed through openings in the legs of the contact spring and lies in a plane that intersects orthogonally with both legs. The spring ring is interrupted at one point of its circumference, and its free ends are attached in a region of the legs that is oriented towards the open end of the contact spring. The openings in the legs through which the contact spring is passed are located closer towards the connecting region of the legs. As a result, bracket-shaped projections are formed on the external sides of the legs which compress the contact spring when the inner part is rotated to a closed position.
The current collector rail, which is formed from an electrically conductive material, in particular metal, is formed such that it can accommodate the connecting pin of the lamp. It is therefore arranged in the inner part such that it is oriented in the same direction as the connecting pin when the latter is arranged inside the socket assembly together with the pinch seal. This direction typically corresponds to the direction of longitudinal extension of the lamp, which in turn coincides with the rotation axis about which the lamp is rotated for securing it in the socket assembly. To accommodate the connecting pin, the current collector rail advantageously has a channel-shaped region extending parallel to the rotation axis. Moreover, it preferably has at least one and more preferably two contact surfaces which extend(s) at the side of the channel-shaped region in the direction of the arching of the channel-shaped region, in the case of two contact surfaces preferably parallel to one another. These contact surfaces serve to establish an electrical contact between the connecting pin and the electric circuit of the socket assembly when the inner part inside the outer housing part is rotated to a closed position. As already described, the socket assembly is preferably configured such that a closed position is reached irrespective of whether the inner part in the outer housing part is rotated clockwise or counterclockwise. The contact surfaces arranged on both sides ensure that a reliable electrical contact is formed in both cases. The dimensions of the at least one contact surface are also based on the requirement that an electrical contact is established in a closed position, whereas in the open position this is not the case. In a simple variant, the at least one contact surface is configured as a rectangular stripe. It is, however, preferred to bend the end of the at least one contact surface facing away from the channel-shaped region such that in a closed position the contact is established via the bent region of the contact surface. In this manner, it is possible to establish a reliable contact across a relatively large contact surface.
The outer housing part and the inner part consist of a non-conductive material, in particular a plastic material, more particularly an injection-moldable plastic material. A material which has been found to be particularly suitable for this is polybutylene terephthalate (PBT). Glass-fiber reinforced polybutylene terephthalate is particularly preferably employed due to its high stability. If an injection molding process is used, the outer housing part and the inner part can be produced in a particularly cost-effective manner.
The present invention will now be described in more detail with reference to the accompanying drawings. The drawings relate to preferred embodiments of the present invention without limiting the present invention to these embodiments. The figures are purely schematic and like parts are designated by like reference numerals, although not all parts are designated by reference numerals in all drawings. In the schematic drawings:
In
In each of
In contrast to this,
The fixation of the pinch seal 20 in the socket assembly is achieved using the two leaf springs 5, 5′ which are attached in the end face region of the inner part 4 facing the lamp 2. The two leaf springs are configured identically and arranged such that their head regions face each other.
The leaf spring 5 is attached to the inner part 4 in its shaft region, which is achieved by an arrangement in which the shaft portions 53, 53′, 530, 530′ are slipped into a complementary, approximately triangular groove 41 in the end face region of the inner part 4 adjacent to the lamp 2. As can be taken, in particular, from
Once the pinch seal 20 has been inserted to the desired position inside the socket assembly, the connecting pin 21 comes to rest in the channel-shaped region 71 of the current collector rail 7, which is in turn arranged on a support projection 44 protruding into the free space 40 of the inner part 4 (see
Details of the contact spring 6 are best seen in
As can be seen in
As already described above, the socket assembly may be configured such that the free space 40 is reduced upon rotation from the open position to a closed position to thereby compress the various springs used in the socket assembly. In a first variant, this causes exertion of pressure on the contact spring 6, in the shown example specifically the parts of the spring ring 61 which protrude beyond the external sides of the legs 60, 60′. In the shown example, this is achieved through the fact that the cavity 30 is not exactly cylindrical but is slightly oblate on the side of the slotted opening 31 and the side opposite said side, so that it has a smaller diameter in these regions than in the regions shifted by 90° with closed wall 34. As a result, upon rotation from the open position to a closed position shifted by 90°, the inner part 4 is somewhat compressed from the side of the slotted opening 31 and the opposite side. This causes a reduction of the distance between the wall 45 of the inner part 4, which surrounds the free space 4, and the legs 60, 60′ of the contact spring 6. The wall 45 abuts the lateral projections of the spring ring 61 and compresses the contact spring 6, so that the contact between the internal side of the leg 60′ and the ends 700, 700′ of the contact surfaces 70, 70′ is increased.
The reduction of the free space 40 also has a similar effect on the leaf springs 5, 5′. When the inner part 4 is rotated to a closed position, the resting faces 50, 50′ are brought closer together, so that they bear against the pinch seal 20 with increased pressure and thus fix it particularly reliably. Upon rotation of the socket assembly back to the open position, the free space 40 widens again, the pressure on the springs is reduced, and the lamp can be removed from the socket assembly more easily. This also reduces the risk of damage to the pinch seal 20.
While the present invention present has been illustrated by description of various embodiments and while those embodiments have been described in considerable detail, it is not the intention of Applicants to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily appear to those skilled in the art. The present invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicants' invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 004 589 | Jun 2018 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4998040 | Emunds et al. | Mar 1991 | A |
| 5531613 | Takano | Jul 1996 | A |
| 20130170194 | Osada | Jul 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 39 03 892 | Aug 1990 | DE |
| 1029855 | Nov 2006 | NL |
| Number | Date | Country | |
|---|---|---|---|
| 20190376674 A1 | Dec 2019 | US |
