EP0424257A2

EP0424257A2 - Locking device for connectors

Info

Publication number: EP0424257A2
Application number: EP90402922A
Authority: EP
Inventors: Yukio C/O Daiichi Denshi Kogyo K.K. Saito; Yoshiaki C/O Daiichi Denshi Kogyo K.K. Igarashi
Original assignee: DDK Ltd
Current assignee: DDK Ltd
Priority date: 1989-10-20
Filing date: 1990-10-17
Publication date: 1991-04-24
Also published as: CA2027739A1; JPH089910Y2; JPH0362467U; EP0424257A3

Abstract

A locking device for connectors includes levers rockably provided on both sides of one of the connectors and latches provided on both sides of the other connector. Each of the levers has a removing pawl extending toward the other lever and a latch piece to be engaged with the latches of the other connector to lock the connectors. When the levers are rotated for unlocking the connectors, a removed distance of one connector relative to the other connector during a first half period of the rotation of the levers is made smaller than a removed distance of the one connector during the latter half period of the rotation of the levers. The above arrangement of the levers ensures that clearances between the latch pieces and the latches are as small as possible and an ultimate removed distance of the one connector from the other connector is sufficient.

Description

This invention relates to a locking device for connectors, particularly rectangular connectors.
One example of hitherto used rectangular connectors is depicted in Figs. 1a and 1b. Fig. 1a explanatorily illustrates the entire connector in a schematic view and Fig. 1b is a sectional view taken along a line Ib-Ib in Fig. 1a. The connector consists of a cable side connector 10 arranged on a side of a cable and a substrate side connector 20 arranged on a side of a substrate. The cable side connector 10 is formed by a main body 12 having an upper surface 14. The main body 12 is formed with side pieces 16 extending on both sides of the main body 12. Each of the side pieces 16 is formed on its inside with latches 18 for locking the connectors.
The substrate side connector 20 is formed by a main body 22 having a lower surface 24. The main body 22 is formed with brackets 26 extending on both side of the main body 22. A lever 30 for locking is rockably supported on each of the brackets 26 by means of a pin 28. Each of the levers 30 is formed at its lower end with a latch piece 32 to engage the latches 18 for locking the connectors (Fig. 1b) and formed with a removing pawl 34 extending from a mid portion of the lever 30 in a direction facing inwardly of the substrate side connector 20.
With this arrangement as above described, the levers 30 are operated in the following manner. When the substrate side connector 20 is fitted in the cable side connector 10, the upper surface 14 of the cable side connector 10 and the lower surface 24 of the substrate side connector 20 come into contact with each other and the substrate side connector 20 is locked to the cable side connector 10 so as not to remove therefrom with the aid of engagements of the latches 18 and the latch pieces 32. Fig. 2a illustrates this locked condition of the latches 18 and the latch piece 32. Other portions of the connectors having nothing to do with the locking are not shown in Figs. 2a-2d and only one of the two levers 30 is shown in the drawings. The two levers 30 are used in actual cases. However, as only one lever 30 is shown in the drawings, the operation of the one lever will be explained herein.
As shown in Fig. 2a, there is a clearance a between the latches 18 and the latch piece 32. Moreover, the removing pawl 34 is in contact with the upper surface 14 of the cable side connector 10.
In order to remove the substrate side connector 20 from the cable side connector 10, the lever 30 is rotated in a direction shown by an arrow 40 (Fig. 2b). As a result, the latch piece 32 is disengaged from the latches 18, and at the same time a distal end of the removing pawl 34 serve as an acting point 36 to force the upper surface 14 of the cable side connector 10 downwardly relative to the substrate side connector 20 so that the substrate side connector 20 is removed from the cable side connector 10.
With the above prior art locking device, however, there is a problem to be solved. This problem will be explained with reference to Figs. 2a-2d.
Fig. 2a illustrates the condition of the cable side and substrate side connectors 10 and 20 fitted with each other as above described. Fig. 2b shows a condition when the lever 30 has been rotated slightly (of the order of 8°). Fig. 2c illustrates a condition at a moment when the latch piece 32 has been disengaged from the latches 18 by a further rotation of the removing pawl 34 (through approximately 11.5° from the locked condition). Fig. 2d shows a condition when the lever 30 has been rotated fully (through about 27° from the locked condition). A dot-and-dash line illustrates the position of the lower surface 24 of the substrate side connector 20 when connectors 10 and 20 are fitted with each other.
In Figs. 2b, 2c and 2d, e, e₁ and e₂ are moved distances of the latch piece 32 of the lever 30 in a direction Y shown by an arrow in the drawing, a, a₁ and a₂ are clearances between the latches 18 and the latch piece 32, and c, c₁ and C₂ are moved distances of the acting point 36 of the lever 30 in the direction Y or removed distances of the substrate side connector 20. Moreover, ϑ, ϑ₁ and ϑ₂ are rotated angles of the lever 30, and ℓ₁ is a distance between an axis of the pin 28 and the acting point 36.
With the above definitions, it is assumed that the latch piece 32 is disengaged from the latches 18 when the lever 30 has been rotated through ϑ₂. At this moment, the cable side connector 10 has been lowered through the distance c₂ relative to the substrate side connector 20.
In such a case, it is preferable that the removed distance c₂ and the ultimate removed distance c (Fig. 2d) are as large as possible. In consideration of this point, a longer ℓ₁ is better because c is in proportion to ℓ₁.
On the other hand, the clearance a₁ until the latch piece 32 disengages from the latches 18 is indicated by an equation, a₁=a+e₁-c₁. The a₁ must fulfill a relation, a₁>0. (If the relation is not the case, the latch piece 32 engages the latches 18 on the way so that the substrate side connector 20 could not be removed from the cable side connector 10.)
Therefore, it is needed to fulfill the relation, a₁=a+e₁-c₁>0 until the lever 30 has been rotated through ϑ₂. For this purpose, c₁ which is not very large is on the safety side. In view of this, ℓ₁ is needed to be short.
Moreover, the clearance a upon the connectors being fitted could not be very large because the latches 18 and the latch piece 32 not serve as locking means if the clearance a is large.
Therefore, a larger ℓ₁ is better in consideration of the removed distance, but smaller ℓ₁ is preferable in the viewpoint that the clearance a must be as small as possible for a good fitting of the connectors and the latch piece 32 must be prevented from engaging the latches 18 when disconnecting the connectors 10 and 20. Accordingly, the locking device of the prior art involves a difficulty that the two contradictory conditions with respect to the distance ℓ₁ should be simultaneously fulfilled.
It is an object of the invention to provide an improved locking device for connectors, which fulfills the conditions contrary to each other as to distances between pivoted points and acting points of levers for locking.
In order to accomplish this object, according to the invention a removing pawl of each of levers for locking is provided with a second acting point in addition to a first acting point. When the levers are rotated in removing directions, the second acting points of the removing pawls first contact an upper surface of a cable side connector and then the first acting points contact the upper surface.
With this arrangement, when the levers are rotated in the removing directions, the second acting points first contact the upper surface of the cable side connector, and thereafter the first acting points contact the upper surface of the cable side connector. In other words, the locking device according to the invention is so constructed that the second acting points near pivotal points of the levers serve to move the cable side connector downward until latch pieces of the levers disengage from latches of the cable side connector, and thereafter only the first acting points serve to move the cable side connector downward. Therefore, an ultimate removed distance between the connectors can be large, despite the fact that an initial clearance between the latches and the latch pieces can be small.
The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.

Fig. 1a is an explanatory view of a locking device of the prior art;
Fig. 1b is a sectional view of the device taken along the lines Ib-Ib in Fig. 1a;
Figs. 2a-2d are explanatory views for explaining the operation of the device of the prior art;
Fig. 3a is an explanatory view of main parts of the device according to the invention;
Figs. 3b-3d are explanatory views for explaining the operation of the main parts shown in Fig. 3a;
Figs. 4a-4d are explanatory views illustrating operations of a lever having only a first acting point in comparison with that of the device according to the invention;
Figs. 5a-5d are explanatory views illustrating operations of a lever having only a second acting point in comparison with that of the device according to the invention;
Figs. 6a, 6b and 6c are explanatory views of levers of other embodiments of the invention; and
Fig. 7 is an explanatory view of a further embodiment of the invention.

In the embodiments shown in Figs. 3a-3d to Fig. 7, like components are designated by the same reference numerals as those in Figs. 1a and 1b and 2a-2d. According to the invention, each of removing pawls 34 of a lever 30 is provided with a second acting point 38 in addition to the acting point 36 for fulfilling the conditions of the distance ℓ₁ above described.

(1) First embodiment

Referring to Fig. 3a, a lower surface of a removing pawl 34 is formed with a step to form two surfaces in a manner that an inner corner becomes a first acting point 36 and a corner nearer a pin 28 becomes a second acting point 38.
The operation of the removing pawl 34 provided with such double acting points 36 and 38 will be explained with reference to Figs. 3a-3d. Fig. 3a illustrates a condition where cable side and substrate side connectors 10 and 20 have been fitted with each other. Fig. 3b shows a condition when the lever 30 has been rotated slightly (of the order of 8°) for the purpose of removing one connector. Fig. 3c illustrates a condition at a moment when a latch piece 32 has been disengaged from latches 18 by a further rotation of the lever 30 (through approximately 11.5° from the locked condition). Fig. 3d shows a condition when the lever 30 has been rotated fully (through about 27° from the locked condition).
When the locking lever 30 is started to be rotated, the second acting point 38 first forces the cable side connector 10 downward. According to the invention, a distance ℓ₄ between the second acting point 38 and an axis of a pin 28 is made as short as possible, and the second acting point 38 is made operative until the latch piece 32 disengages from the latches 18 as shown in Fig. 3c. As a result, a removed distance c₂ until the latch piece 32 disengages from the latches 18 is small. Therefore, even if an initial clearance a is small, such a small clearance does no interfere with the disengagement between the latch piece 32 and the latches 18.
According to the invention, moreover, the lever 30 is so constructed that after the disengagement of the latch piece 32 from the latches 18, the first acting point 36 serves to remove the substrate side connector from the cable side connector 10. In this case, by making suitably long a distance ℓ₅ between the first acting point 36 and the axis of the pin 28, an ultimate removed distance c becomes large.
In comparison of the feature according to the invention with other features, Figs. 4a-4d and Figs. 5a-5b illustrate a lever 30 having only a first acting point 36 and a lever 30 having only a second acting point 38, respectively.
With the lever 30 having only the first acting point 36, if an initial clearance a is equal to that of the above embodiment, a latch piece 32 engages latches 18 on the way of removing as shown in Fig. 4b so that a substrate side connector 20 could not be removed from a cable side connector 10. If the locking lever 30 is forced to rotate, a corner of either the latch piece 32 or the latches 18 will be torn off.
On the other hand, with the lever 30 having only the second acting point 34, an ultimate removed distance c is too small (Fig. 5d), so that a substrate side connector could not be completely removed from a cable side connector.
This embodiment was applied to a rectangular connector of 7 mm in width and 49 mm in length. Each of levers 30 had a 4 mm width and a 16 mm length. A distance between a pin 28 and a latch piece 32 was 2.5 mm in an X direction and 4.5 mm in a Y direction. A distance between the pin 28 and a first acting point 36 was 5.7 mm in the X direction and 1.3 mm in the Y direction. A second acting point 38 was spaced from the first acting point 36 by 2 mm in the X direction and 0.35 mm in the Y direction.
The lever 30 may be preferably made of a resin by injection molding. The resin for the lever 30 may be any of various kinds of resins which are not necessarily be particularly hard. In the case of relatively small sizes of the lever above described as an actual case, however, in order to ensure a relatively high molded accuracy, it is preferable to use a resin mixed with glass fibers, such as polycarbonate (PC), polybutylene terephthalate (PBT), polyamide (PA), polyphenylene sulfide (PPS), liquid crystal polymer (LCP) or the like.

(2) Modifications of the first embodiment

The step between the acting points 36 and 38 of the locking lever 30 as shown in Fig. 3a is not necessarily needed. In stead thereof, there may be a flat surface (Fig. 6a) or a curved surface (Fig. 6b) between the acting points 36 and 38. Moreover, a removing pawl 34 may be formed with a notch 40 in a lower surface at a bottom of the pawl 34 so that a second acting point 38 extends.
As can be understood from the explanation of the operation of the first embodiment, it is only required according to the invention that when the levers are rotated, the second acting points 38 near the pins 28 serve to lower the cable side connector 10 until the latch pieces 32 disengage from the latches 18, and thereafter only the first acting points 36 serve to lower the cable side connector 10 relative to the substrate side connector 20.

(3) Second embodiment

The invention is applicable to a case that levers 30 are provided on the side of the cable side connector 10 as shown in Fig. 7. In other words, by providing removing pawls 34 of levers 30 with first and second acting points 36 and 38, the removing pawls 34 are readily removed from the latches 18 and an ultimate removed distance can be large enough even if the initial clearance a is small.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.

Claims

1. A locking device for connectors, said device including levers rockably provided on both sides of one of the connectors, each lever having a latch piece and a removing pawl extending inwardly, and latches provided on both sides of the other connector, and when the connectors are fitted with each other to bring their opposed surfaces into contact with each other, said connectors being locked to prevent their removal from each other by engagement of the latch pieces and the latches, while when the levers are rotated in removing directions, the engagement of the latch pieces and the latches being released and one portion of the removing pawl of each of the levers being brought into contact with the opposed surface of the other connector to serve as an acting point of a lever for forcing the other connector away from the one connector, wherein the removing pawl of each of the levers is provided with a second acting point in addition to said first mentioned acting point in a manner that when each of the levers is rotated in the removing direction, the second acting point first contacts the opposed surface of the other connector and then the first mentioned acting point contacts the opposed surface of the other connector.

2. A locking device for connectors as set forth in claim 1, wherein a lower surface of said removing pawl of each of the levers is formed with a step to form two surfaces thereon so that a distal corner is the first mentioned acting point and a corner of the step nearer a pivotal point of the lever is the second acting point.

3. A locking device for connectors as set forth in claim 2, wherein a flat surface is formed between the first mentioned acting point and the second acting point.

4. A locking device for connectors as set forth in claim 2, wherein a curved surface is formed between the first mentioned acting point and the second acting point.

5. A locking device for connectors as set forth in claim 2, wherein the lower surface of the removing pawl is formed with a notch between the second acting point and the pivotal point of the lever.