Locking system for push-in bulb units in decorative light sets

专利摘要:
A push-in type light unit for a decorative light string has a lock between a plastic push-in bulb unit and a complementing plastic socket unit. The bulb unit has bulb holder with an outwardly-biased integral flexible hook-like locking finger which passes through a U-shaped keeper extending laterally from the socket unit and presenting an outer shoulder engaged by the bill of the finger to lock the bulb and socket units together. Manual pressure exerted on the head of the bill releases the locking finger to separate the bulb unit from the socket unit for bulb replacement.
公开号:CA2289894A1
申请号:C2289894
申请日:1999-11-18
公开日:2000-05-19
发明作者:Joseph M. Ahroni
申请人:Joseph M. Ahroni；
IPC主号:F21S10-06

专利说明:
LOCKING SYSTEM FOR PUSH-IN BULB UNITS IN DECORATIVE LIGHT SETS TECHNICAL FIELD The present invention relates to decorative light sets with push-in type bulb holders, and more particularly to a manner of locking the bulb holders in positron. BACKGROUND OF THE INVENTION Decorative light strings commonly have miniature push-in type bulb units fitting into plastic socket units mounted at regular intervals on insulated multi-wire cords. Normally, the bulb units consist of a plastic holder receiving a miniature bulb having its two filament wires projecting endwise from the holder and doubling back on opposite sides of the holder so as to be gripped between the holder and a pair of contacts inside the socket unit into which the bulb unit is pushed. The contacts project into a wireway at the base end of the socket unit and make contact with one of the wires by piercing the insulation. Although it is common to rely upon friction to hold the bulb unit in place, it is preferred to provide a positive lock. However, since a bulb may have to be replaced occasionally, it is desired that the locking elements not only be easy to engage, but also easy to release so that units can be readily withdrawn from the socket units. SUMMARY OF THE INVENTION Various locking arrangements for push-in type bulb units are known in the art. For example, in Figure 4 of Patent No. 4,679,126, the upper rim of the bulb unit snaps over and is retained by heads of inwardly facing hooks which stand up from the top of the related socket unit. Patent Nos. 4,943,899 and 4,970,632 show fastening arrangements in which flexible locking tongues project outwardly from the bulb units and are beat downwardly to interfit with complementary retainers on the socket units after the bulb units are pushed into operating position. Figures 1-S of Patent No. 5,154,508 show a locking system in which a locking hook is mounted on a pair of arms projecting laterally from the bulb unit so that the bill of the hook snaps over a sloped lug extending laterally from the socket unit and interfits with a shoulder at the underside of the lug. The shank of the locking hook has an upward extension which, when pressed, releases the hook from the shoulder. Figures 6 and 7 of Patent No. 5,154,508 show a similar system, and Figures 8-10 show another locking arrangement in which a T-shaped swing leg on the bulb unit can be swung downwardly to snap fit between a pair of locking ears on the socket unit.It is important that the cooperating locking elements on the bulb unit and socket unit be such as not to complicate injection molding of the units, and that they be easily engaged while pushing in the bulb units, and be easily released when desired while providing a positive lock under normal conditions. With these criteria in mind, the present invention claims to provide an improved effective locking system which is particularly easy to intentionally release. In accordance with the present invention, the bulb unit is injection molded to provide a downwardly sloping spring finger with an outwardly facing hook element at its lower end. The socket unit in turn is injection molded to provide an outwardly extending U-shaped keeper member providing a central opening for passage of the spring finger when the finger is pressed inwardly to a vertical position, and providing a locking shoulder at its underside for engagement by the bill of the hook after it has passed through the keeper member and the spring finger has then responsively sprung outwardly to the extent permitted by the width of the passage.Release of the lock is performed by exerting slight manual inward pressure on the nose of the bill whereupon the tension on the retained spring finger aids in urging the finger to move such as to cause the hook to enter the passage and the bulb unit to start to separate endwise from the socket member. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing one of the light units mounted on a cord; Figure 2 is an exploded view of the Figure 2 assembly;
Figure 3 is a side elevational view of a push-in bulb unit; Figure 4 is a perspective view, partly broken away, of the socket unit; Figure 5 is a bottom view of one of the light units mounted on a cord;and Figure 6 is a longitudinal sectional view taken as indicated by line 6-6 in Figure 5. DETAILED DESCRIPTION OF THE INVENTION For purposes of example, the present invention is illustrated as being applied to light units 10 like those shown in Patent No. 5,829,865, and namely, with the present invention being substituted for the locking element shown therein. The light units 10 include an injection-molded two-piece plastic lampholder consisting of a socket unit 22 and a generally U-shaped base unit 23 which have a snap interfit and provide therebetween a wireway 20 for passage of a cord 19 having three insulated wires for example. The socket unit 22 provides a generally circular socket cavity 22a along the length for receiving a push-in bulb assembly 24 having an injection-molded plastic bulb holder 25 in which a bulb 26 with a pair of leads 26a from its filaments is mounted. Each lampholder also has a pair of elongated push-in contact elements 28 located in guideways 29 between ribs 30-30a at opposite sides of the socket cavity 22a and arranged to project into the wireway 20. There the contact elements 28 pierce the insulation of the cord 19 so as to engage the center wire 19a of the cord on opposite sides of a respective cutout 21 in the wire. Projecting from the socket unit 22 on opposite sides of the wireway 21 are two locking legs 32 presenting opposed locking shoulders 32a adjacent their outer end for interfitting with the base unit 23. These shoulders 32a are adjoined by beveled lead-in faces 32b. The inner face of each locking leg 32 is transversely concave matching the curvature of the socket cavity 22a. The base unit 23 has a pair of flexible guide fingers 34 shaped to engage the lead-in faces 32b and be flexed at their root end toward one another responsive to pushing of the base unit 23 and socket housing 22 together from opposite sides of the cord 19 after the base unit 23 has been positioned with the cord 19 straddled by the fingers 34 at the site of the cutout 21. At their root end the fingers 34 have retaining shoulders 35 between curved base flanges 36, 36'. These shoulders 35 are engaged by the locking shoulders 32a when the base unit 23 and socket unit 22 are snap-fitted S together over the cord 19. The guide fingers are preferably arched transversely to provide each with a convex outer guide face 34a complementing the concave inner guide face of the respective locking leg 32, and the free end of each guide finger 34 is preferably rounded and beveled on its convex outer side as indicated at 34b. The base unit 23 presents a post 37 arranged between the fingers 34 to project into the cutout 21 in the center wire of the cord 19.The bulb holder 25 has a central socket 40 to receive the bulb 26. This socket 40 is provided in a round plug 42 having an outwardly flared annular rim 43 spaced above its lower end, and having a relatively narrow extension 44 with opposite exterior flat side faces 44a between narrow pinch faces 44b. A pair of longitudinal passages 46 extend through the base of the plug 42 and through the length of the extension 44 into a slot 47 located at the free end of the narrow extension and intersecting the narrow faces 44b. These narrow faces 44b are spaced apart slightly less than the diameter of the socket cavity 22a to _ allow for the bulb leads 26a and are aligned with the bottom of positioning grooves 48 which are formed in the plug 42 and extend to an annular shoulder 49 at the base of the flared rim 43. When the bulb 26 is positioned in the bulb holder 25, the lead wires 26a extend from the bulb 26 through the passages 46 and outwardly at opposite ends of the slot 47. Then the leads 26a double back over the narrow pinch faces 44b. When the bulb unit 24 is pushed into the socket unit 22 the bulb leads 26a are pinched between the pinch faces 44b and the contact elements 28 to complete a circuit by-passing the respective cutout 21 in the wire 19a. In accordance with the present invention, the bulb holder 25 is provided with a flexible hook-like locking finger 50 which, when relaxed, slopes outwardly and downwardly at about 75° from a short arm 51 which projects radially outward from the annular rim 43. The finger 50 and arm 51 are molded integrally with the bulb holder 25, and the finger 50 has the relaxed disengaged position shown in Figure 3 when released from the mold. At its frea end the finger 50 has an enlarged head in the form of an outturned locking bill SOa which has an upper locking edge SOb from which it tapers at its outer bottom side by a curved convex edge SOc. At the inside of the bend between the arm 51 and the finger 50 there is a rounded concave juncture SOd so that the finger can readily be flexed inwardly toward the bulb holder to a position perpendicular to the arm and will have a spring-like return when released. The locking finger 50 is complemented by a U-shaped keeper 52 projecting radially outward from the rim of the socket unit 22 to provide a central opening 52a terminating at an outer retaining shoulder 52b at the underside of the retainer. The opening 52a is large enough for passage of the outer end portion of the locking finger 50 when the finger has been flexed inwardly to a position parallel to the longitudinal axis of the bulb holder. When the bulb unit is to be pushed into the socket unit during assembly, the locking finger is flexed inwardly into alignment with the opening 52a of the keeper 52. Then as the bulb unit is pushed into the socket member, the enlarged head of the locking finger passes through the keeper. When the locking edge SOb reaches the level of the retaining shoulder 52b, the locking finger flexes outwardly to engage the locking edge SOb with the retaining shoulder 52b, thereby locking the bulb holder 25 in the socket unit 22. To release the bulb holder form the socket unit, the tapered edge portion SOc is gently manually pressed to flex the finger inwardly sufficiently for the locking edge SOb to clear from the shoulder 52b. As this is being accomplished, the manual pressing against the tapered edge portion SOc also results in sliding of the locking finger into the keeper opening 52a and start of endwise separation of the bulb unit from the socket unit. The two units can then be easily pulled apart so that a replacement bulb can be placed in the bulb holder. It will be appreciated that the locking finger 50 and keeper 52 can be located in different positions than shown, as for example, overlying the cord 19. From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

权利要求:
Claims (7)
[1] 1. A light assembly comprising:a plastic socket unit presenting a socket;a plastic push-in bulb unit in said socket and having a bulb mounted therein;a first locking element integral with a first of said units;a complementing second locking element integral with the second of said units;said first locking element being in locking relationship with the second locking element to lock said units together, and being adapted to be moved out of said locking relationship when it is desired to remove said bulb unit from said socket;said second locking element presenting a stationary keeper spaced outwardly by an opening from said second unit; and said first locking element being hook-like and presenting an outwardly directed locking bill which opposes said keeper when said locking elements are in locking relationship, said first locking element being flexible to an extent permitting said locking bill to be flexed inwardly out of said locking relationship and into alignment with said opening when it is desired to remove said bulb unit from said socket unit.
[2] 2. A light assembly according to claim 1 in which said first and second locking elements are connected, respectively, with said bulb and socket units.
[3] 3. A light assembly according to claim 1 in which said second locking element comprises a generally U-shaped member projecting outwardly from said socket unit, said U-shaped member and socket unit providing said opening, and a central portion of said U-shaped member providing a shoulder acting as said keeper.
[4] 4. A light assembly comprising:a plastic socket unit presenting a longitudinal socket;a plastic push-in bulb unit in said socket and having a bulb mounted therein; a generally U-shaped keeper projecting laterally from said socket unit and providing therewith a longitudinal opening, said keeper presenting a retaining shoulder spaced by one end of said opening from said socket unit, said shoulder facing longitudinally in a direction from said bulb unit; and a flexible finger on said bulb unit having a locking bill arranged to move toward said bulb unit into alignment with said opening when said finger is flexed toward said bulb unit, and said bulb unit is aligned for fitting into said socket unit, said bill being adapted to pass through said opening responsive to said bulb unit then being inserted into said socket unit, and to move outwardly into a retained position facing said shoulder when said finger is then released to flex outwardly.
[5] 5. A light assembly according to claim 4 in which said locking. bill has a tapered head at its outer end arranged to be manually pressed toward said socket unit to initiate release of said locking bill and removal of said bulb unit from said socket unit.
[6] 6. A light assembly according to claim 5 in which said finger is flexibly connected at the outer end of an arm projecting radially from said bulb unit.
[7] 7. A light assembly according to claim 4 in which said finger is flexibly connected to a radial extension of said bulb unit and slopes outward when in a relaxed disengaged position, and in which said locking bill has a tapered head at its outer end, whereby manual pressing of said tapered head toward said socket unit releases said locking bill from said retained position whereupon said bulb unit unseats from said socket unit responsive to flexing action of said finger toward its said disengaged position.

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同族专利:

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引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
2005-11-18| FZDE| Dead|

优先权:

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申请号 | 申请日 | 专利标题

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US19649498A| true| 1998-11-19|1998-11-19||

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US09/196,494||1998-11-19||

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