GB1560521A

GB1560521A - Coupling for connecting two members

Info

Publication number: GB1560521A
Application number: GB3023077A
Authority: GB
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1976-07-22
Filing date: 1977-07-19
Publication date: 1980-02-06
Also published as: JPS5318467U; FR2359311B3; NL7608099A; BE857009A; FR2359311A1

Description

(54) COUPLING FOR CONNECTING TWO MEMBERS (71) We, N.V. PHILIPS' GLOEILAMPENFABRIEKEN, a limited liability Company, organised and established under the laws of the Kingdom of the Netherlands, of Emmasingel 29, Einghoven, the Netherlands do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: The invention relates to a coupling for connecting two members, comprising 1) a sleeve having a connection portion for connecting the sleeve to a first of the two members and a coupling portion for engaging the second of the two members, the coupling portion comprising radiallyresilient lugs, formed by longitudinal slots in the wall of the sleeve, arranged to fit in an aperture in the second member, and 2) a plunger which is movable between two positions in the sleeve and which in a first of the two positions is arranged to secure the coupling portion in the aperture in the second member; the radially-resilient lugs, in order to retain the plunger in the first position, co-operating with a recess provided on the circumference of the plunger.

A coupling of the type described above is known from German Patent Specification 1,204,024.

The coupling of the type described is used for connecting two plate-shaped members bearing against each other with flat surfaces. In the operative condition of the coupling the connection portion of the sleeve is connected to the first member by means of a snap connection and the coupling portion of the sleeve projects through the aperture of the second member.

In the first position of the plunger the lugs of the coupling portion are bent outwardly and a portion of the second member is enclosed between the lugs and the first member. The plunger has a circumferential groove in which the free end of a lug engages in the first position of the plunger.

In a second position of the plunger, the first and second members may be separated.

A drawback of the known coupling is that the radial deflection of the lugs in the first position of the plunger is smaller than the maximum deflection which is achieved during movement of the plunger to the first position. A result of this is that the force which the coupling ultimately exerts on the second member is less than optimum.

Another drawback is that the lugs project beyond the aperture of the second member to such an extent that the part of the lugs which adjoins the fixed end of the lugs and which has only a restricted radial deflection possibility is in contact with the second member.

The result of the said drawbacks is that the two interconnected members are not immovable with respect to each other, due to a small force acting in the longitudinal direction of the coupling. As a result of this a gap is formed between the two plate-shaped members which generally is undesirable from an aesthetic point of view, but especially from a point of view of rigidity.

It is an object of the invention to modify the coupling mentioned in the preamble in such manner that a coupling is obtained with which two members, which may or may not be plate-shaped, can be connected together in such manner that the said draw backs do not occur.

For that purpose the coupling according to the invention is characterized in that, in the first position of the plunger, less than the total number of the lugs of the coupling portion serve to retain the plunger in that position and the free ends of the remaining lugs are bent outwardly by the plunger so as to be able to clamp against the inner surface of the aperture in the second member.

So two types of lugs are to be distinguished in the coupling according to the invention, namely a first type which, in the first position of the plunger, engage in the recess in the circumference of the plunger, and a second type whose free ends are bent outwardly when the plunger moves from its second to its first position. The free ends of the lugs of the second type in the first position of the plunger assume a maximum outwardly bent position.

The advantage of the coupling according to the invention is that two interconnected members are rigidly fixed together in the longitudinal direction of the coupling, the clamping force which is exerted on the second member by the coupling being optimum.

It is to be noted that a coupling is known from an embodiment of the abovementioned German Patent Specification 1,204,024 of which all the lugs have, in the first position of the plunger, the maximum deflection because the above-mentioned recess is not provided in that embodiment.

The drawback of the construction according to that embodiment is that the plunger is not locked against movement away from the first position.

The use of the coupling according to the invention is not restricted to plate-shaped members. Non-plate-shaped members may also be connected together by means of the coupling.

The coupling is particularly suitable for rotatably connecting a luminaire to a supporting member, for example, a wall plate or a supporting arm. A very reliable and firm rotatable connection is obtained when the luminaire has a disc-shaped base plate which has at its circumference an upright edge on which an upright edge of the supporting member fits.

The coupling may consist of a thermoplastic synthetic resin, for example polycarbonate, polyamide, or of a metal, for example aluminium. The coupling may be manufactured as a separate unit or may be formed integral with the first member. In the former case the connection portion of the sleeve is designed so that said portion can be secured to the first member. In the latter case the connection portion of the sleeve is permanently connected to the first member. The coupling is preferably constructed so that the part of the lugs adjoining the free end of the lugs co-operates with the second member.

An embodiment of the coupling is characterized in that the lugs which are deflected in the first position of the plunger are uniformly distributed around the circumference of the sleeve. An advantage of this construction is that, taken at right angles to the longitudinal direction of the coupling, the forces exerted on the second member by the deflected lugs are in equilibrium.

Another embodiment of the coupling is characterized in that, on their radially outer surfaces, the lugs have near their free ends a groove which is oriented transversely to the axis of the sleeve and which in the first position of the plunger is arranged to receive a rim formed on the inner surface of the aperture in the second member. The advantage of a connection produced by means of this coupling is that the members accurately assume a previously-determined position with respect to each other. In addition, said construction contributes to an optimum locking against working loose of the members.

Still another embodiment of the coupling is characterized in that the plunger is locked against rotation by a projection on the plunger which extends in the slot between two adjacent lugs. When the plunger moves axially in the sleeve of the coupling, the projection moves in the slot between the two lugs and prevents rotation of the plunger with respect to the lugs.

An embodiment of the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which Figure la is a side view of a plunger of a coupling according to the invention, Figure ib is a side view of a sleeve of a coupling according to the invention with one quadrant is cut away.

Figure ic is an end view of the sleeve of Figure lb looking towards the lower end thereof, the cut away quadrant of Figure 1b being indicated by the line II - II, Figure 2 is a sectional view of the coupling according to the invention in the locked position, and Figure 3 shows the coupling shown in Figure 2 in the unlocked position.

Figure 1 shows separately the plunger and the sleeve of an embodiment of the coupling according to the invention. A polyamide plunger is denoted by 1 and a polycarbonate sleeve is denoted by 3. In cross-section both parts are substantially circular. The plunger 1 has a cylindrical portion 5 the length and diameter of which are adapted to the dimensions of the sleeve 3. At the upper end of the plunger as viewed in the Figure the cylindrical portion 5 has a flange 7. The portion 5 furthermore comprises, on its circumference, two diametrically situated recesses 9 of which only one is visible in Figure 1. In the longitudinal direction of the portion 5 extend four rib-like extensions 11 which are distributed uniformly around the circumference of the plunger.The plunger furthermore has a second cylindrical portion 13 formed integral with the cylindrical portion 5 and having a smaller diameter. The lower end of the plunger is formed by a truncated conical part 15 the largest diameter of which corresponds approximately to the diameter of the cylindrical portion 5.

The sleeve 3 comprises a connection portion for connecting the coupling to a first member, and a coupling portion for coupling a second member to the first. The connection portion in this embodiment comprises a collar 23 which fits in a suitable recess of the first member. The coupling portion has four lugs formed by slots 17 in the wall of the sleeve. In the assembled condition of the coupling the diametrically situated lugs 19 can engage in the recesses 9 of the plunger 1. The remaining lugs 21 cooperate with the wall of the cylindrical portion 5 of the plunger and are bent outwardly by the cylindrical portion 5.

The construction of the coupling will be described in greater detail with reference to Figures 2 and 3 in which the coupling according to the invention is used for the rotatable connection of a luminaire to a wall plate. In this embodiment the sleeve 3 of the coupling is formed integral with the base plate 25 of a luminaire 27 which is shown diagrammatically. The base plate has a circumferential edge 29 which fits on a cooperating edge 31 of the wall plate 33. The wall plate 33 has a circular aperture 35, bounded by a wall 37, for receiving the coupling portion of sleeve 3 of the coupling.

The coupling shown in Figure 2 is in the locked position in which the plunger 1 assumes the aforesaid first position. The lugs 21 are bent outwardly by the portion 5 of the plunger I and engage the wall plate 33 by means of a rim 39 on the wall 37 engaging in a groove 41 which is provided on the outer surface of the lugs. The lugs 19 engage in the recesses 9 and lock the plunger against undesired axial displacement.

The shape of each recess 9 is chosen to be such that the plunger 1 cannot be moved downward (as viewed in the Figures) against the resilience of the lugs 19 by manual force but can be moved downward by means of a tool, for example a screwdriver 43. In order to make the plunger accessible for a screwdriver, the base plate 25 has a local recess 45. When the plunger has been moved downward to its second position, the base plate 25 can easily be taken from the wall plate 33. This position is shown in Figure 3.

The lugs 19 and 21 now engage the second cylindrical portion 13 of the plunger, so that the plunger is locked against further downward movement. The rib-shaped projections 11 are located in the respective slots 17 between the lugs. The projections 11 ensure that the plunger 1 is always oriented so that in the first position of the plunger the lugs 19 can engage the recesses 9.

WHAT WE CLAIM IS: 1. A coupling for connecting two members, comprising 1) a sleeve having a connection portion for connecting the sleeve to a first of the two members and a coupling portion for engaging the second of the two members, the coupling portion comprising radiallyresilient lugs, formed by longitudinal slots in the wall of the sleeve, arranged to fit in an aperture in the second member, and 2) a plunger which is movable between two positions in the sleeve and which in a first of the two positions is arranged to secure the coupling portion in the aperture in the second member, the radially-resilient lugs, in order to retain the plunger in the first position, co-operating with a recess provided on the circumference of the plunger, characterized in that, in the first position of the plunger, less than the total number of the lugs of the coupling portion serve to retain the plunger in that position and the free ends of the remaining lugs are bent outwardly by the plunger so as to be able to clamp against the inner surface of the aperture in the second member.

2. A coupling as claimed in claim 1, characterized in that the lugs which are bent outwardly in the first position of the plunger are uniformly distributed around the circumference of the sleeve.

3. A coupling as claimed in claim 1 or 2, characterized in that, on their radially outer surfaces, the lugs comprise near their free ends a groove which is oriented transversely to the axis of the sleeve and which in the first position of the plunger is arranged to receive a rim formed on the said inner surface of the aperture.

4. A coupling as claimed in claim 1, 2 or 3, characterized in that the plunger is locked against rotation by a projection on the plunger which extends in the slot between two adjacent lugs.

5. A coupling for connecting two members substantially as herein described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. viewed in the Figure the cylindrical portion 5 has a flange 7. The portion 5 furthermore comprises, on its circumference, two diametrically situated recesses 9 of which only one is visible in Figure 1. In the longitudinal direction of the portion 5 extend four rib-like extensions 11 which are distributed uniformly around the circumference of the plunger. The plunger furthermore has a second cylindrical portion 13 formed integral with the cylindrical portion 5 and having a smaller diameter. The lower end of the plunger is formed by a truncated conical part 15 the largest diameter of which corresponds approximately to the diameter of the cylindrical portion 5. The sleeve 3 comprises a connection portion for connecting the coupling to a first member, and a coupling portion for coupling a second member to the first. The connection portion in this embodiment comprises a collar 23 which fits in a suitable recess of the first member. The coupling portion has four lugs formed by slots 17 in the wall of the sleeve. In the assembled condition of the coupling the diametrically situated lugs 19 can engage in the recesses 9 of the plunger 1. The remaining lugs 21 cooperate with the wall of the cylindrical portion 5 of the plunger and are bent outwardly by the cylindrical portion 5. The construction of the coupling will be described in greater detail with reference to Figures 2 and 3 in which the coupling according to the invention is used for the rotatable connection of a luminaire to a wall plate. In this embodiment the sleeve 3 of the coupling is formed integral with the base plate 25 of a luminaire 27 which is shown diagrammatically. The base plate has a circumferential edge 29 which fits on a cooperating edge 31 of the wall plate 33. The wall plate 33 has a circular aperture 35, bounded by a wall 37, for receiving the coupling portion of sleeve 3 of the coupling. The coupling shown in Figure 2 is in the locked position in which the plunger 1 assumes the aforesaid first position. The lugs 21 are bent outwardly by the portion 5 of the plunger I and engage the wall plate 33 by means of a rim 39 on the wall 37 engaging in a groove 41 which is provided on the outer surface of the lugs. The lugs 19 engage in the recesses 9 and lock the plunger against undesired axial displacement. The shape of each recess 9 is chosen to be such that the plunger 1 cannot be moved downward (as viewed in the Figures) against the resilience of the lugs 19 by manual force but can be moved downward by means of a tool, for example a screwdriver 43. In order to make the plunger accessible for a screwdriver, the base plate 25 has a local recess 45. When the plunger has been moved downward to its second position, the base plate 25 can easily be taken from the wall plate 33. This position is shown in Figure 3. The lugs 19 and 21 now engage the second cylindrical portion 13 of the plunger, so that the plunger is locked against further downward movement. The rib-shaped projections 11 are located in the respective slots 17 between the lugs. The projections 11 ensure that the plunger 1 is always oriented so that in the first position of the plunger the lugs 19 can engage the recesses 9. WHAT WE CLAIM IS:

1. A coupling for connecting two members, comprising 1) a sleeve having a connection portion for connecting the sleeve to a first of the two members and a coupling portion for engaging the second of the two members, the coupling portion comprising radiallyresilient lugs, formed by longitudinal slots in the wall of the sleeve, arranged to fit in an aperture in the second member, and 2) a plunger which is movable between two positions in the sleeve and which in a first of the two positions is arranged to secure the coupling portion in the aperture in the second member, the radially-resilient lugs, in order to retain the plunger in the first position, co-operating with a recess provided on the circumference of the plunger, characterized in that, in the first position of the plunger, less than the total number of the lugs of the coupling portion serve to retain the plunger in that position and the free ends of the remaining lugs are bent outwardly by the plunger so as to be able to clamp against the inner surface of the aperture in the second member.