WO2010126666A1

WO2010126666A1 - Electrical connector

Info

Publication number: WO2010126666A1
Application number: PCT/US2010/028413
Authority: WO
Inventors: Raymond George Evans; Ian David Edward Sanger
Original assignee: Illinois Tool Works Inc.
Priority date: 2009-04-28
Filing date: 2010-03-24
Publication date: 2010-11-04
Also published as: GB0907282D0; GB2481746A; WO2010126666A8; GB201117257D0

Abstract

An electrical connector comprises a first part (12) from which a cable 36 extends, and a second part 14 that is for connection to an electrical device 60. The first and second parts (12, 14) include complementary butting electrical contacts (32, 48) for making an electrical connection and, separately, complementary ball stud and clip fasteners (68, 80) for releasably securing the first and second parts (12, 14) together. The ball stud and clip fasteners (68, 80) are selected so that the first and second parts (12, 14) become disconnected when a separation force, due to a pull on the cable (36) exceeds a threshold. Thus, if the cable is inadvertently disturbed, such as by somebody accidentally stepping on it, rather than causing the person to trip or the electrical equipment to be disturbed or damaged, the connector (10) disconnects. The invention separates the functions of electrical and mechanical connection, enabling an instant, clean and non-directional separation.

Description

ELECTRICAL CONNECTOR

Background to the Invention

Electrical equipment is often connected to, for example, a power source or to another piece of electrical equipment via a cable. Conventionally, electrical connection between a cable and a piece of electrical equipment is made using a connector system such as complementary male and female electrical contacts (e.g. pin and socket style), with one or other of the male and female parts being at an end of the cable and with the complementary part being on the piece of electrical equipment.

Connection and disconnection of the complementary parts of such conventional connector systems is made in an axial direction, due to the need for aligned, translational relative movement of the male and female parts. Friction between the male and female contacts must be overcome in order to connect or disconnect the connector system. In such prior electrical connectors, the electrical connection and the mechanical connection of the complementary parts are carried out by the same features. For example, in the pin and socket style of connectors, the pins and sockets releasably hold the two parts together by frictional contact and at the same time the contact between the conductive pins and sockets makes the electrical connection. Alternatively, it is also known to separate these functions by, for example, providing a separate mechanical latch or friction lock feature in addition to complementary contacts.

It is well known that such cables trailing from electrical equipment can be a safety hazard. If somebody accidentally steps or otherwise pulls or tugs on the cable, they might trip and/or they might damage the equipment. One way to reduce the risk of this happening is to position the equipment and the cables so that the cables are not in exposed positions. However, that is not always feasible, particularly where the electrical equipment needs to be moved around continually.

Another solution to this problem has been to use connectors that are held in place magnetically. This concept has been used in Apple™ laptop computers and in the power connectors of deep fat fryers and other countertop cooking appliances so that if the cable is tugged it will disconnect, avoiding the equipment being tugged to the floor or being otherwise disturbed or damaged.

However, magnetic connectors are susceptible to overheating. Moreover, there are problems associated with having a magnetic field in proximity to electrical components, such as possible interference.

There is therefore a need for a mechanical connector that easily disconnects.

Summary of the Invention

According to the invention, there is provided an electrical connector, comprising: a first part having a front surface and a rear surface; and a second part having a front surface and a rear surface, the first and second parts being interconnectable via a mating connection of the front surface of the first part with the front surface of the second part; wherein the mating connection is provided by means of at least one ball stud and clip fastener, the ball stud projecting from the front surface of one of the first and second parts and the associated clip being located on the front surface of the other of the first and second parts; and wherein an electrical connection is made across the first and second parts when mated by virtue of at least one contact in the first part being brought into butting connection with at least one corresponding contact on the second part.

In contrast to prior electrical connectors, the invention separates the functions of making an electrical connection and forming a releasable mechanical connection between the complementary parts. Moreover, the separation force required to disconnect the parts may be carefully selected by appropriate design of the at least one ball stud and clip fastener.

The first and second parts may each comprise multiple respective butting contacts.

The butting contacts are spring loaded on one side to give a controlled contact force, thus ensuring a reliable connection. The electrical connector may comprise multiple ball stud and clip fasteners to facilitate other connector designs, providing a more controlled separation.

Typically, the first part comprises a cable. The cable may extend from the rear surface of the first part. The first part may further comprise solder or crimp terminations for the cable. The second part may be attached to a device, in which case the second part may comprise a PC style connector having surface mount terminations.

Brief Description of the Drawings

The invention will be described, by way of example, with reference to the accompanying drawings, in which:

Fig.1 is an exploded perspective view of the components of a connector in accordance with the present invention;

Fig. 2 is a reverse perspective view of the assembled connector, showing the two parts connected;

Fig. 3 is a plan view of the assembled connector, showing the two parts connected;

Fig. 4 shows, from the rear of the part that is for attachment to a device, the assembled connector, with the two parts connected;

Fig. 5 is a cross-sectional view through A-A;

Fig. 6 shows, from the rear of the part that includes the cable, the assembled connector, with the two parts connected;

Fig. 7 is a cross-sectional view through B-B;

Fig. 8 is a detail view of portion M of Fig. 5, showing the butting contacts; Fig. 9 is a detail view of portion N of Fig. 5, showing the ball stud and clip fastener; and

Fig. 10 is a perspective view of the two parts of the connector, shown in a disconnected condition.

Detailed Description

The electrical connector of the invention, indicated generally at 10, comprises complimentary first and second parts 12, 14. The first part 12 has a front surface 16 and a rear surface 18. The second part 14 has a front surface 20 and a rear surface 22. The first and second parts 12, 14 are interconnectable via a mating connection of the front surface 16 of the first part 12 with the front surface 20 of the second part 14.

The first part 12 comprises a plate 24 with a central hole 26 surrounded by a boss 28 that projects from the rear surface 18 towards the rear of the first part. A termination block 30 is received in the hole 26. The termination block comprises twelve contacts 32 substantially aligned with, but protruding slightly from the front surface 16, each contact having a respective solder or crimp termination 34 projecting from the rear surface 18 of the first part 12. A cable 36 extends from the rear surface 18, with internal wires being connected to the terminations 34 by crimp or solder.

A cable cover sheath 38 is received on the boss 28 and projects towards the rear of the first part 12, surrounding and protecting the end of the cable 36 that is connected to the termination block 30.

As best shown in Fig. 9, a pair of ball studs 80 project forwards from respective sides of the front surface 16 of the first part 12. The ball studs comprise mushroom- shaped projections, each having a stem 82 with a first end 82a connected to the plate 24 and second end 82b with a bulbous head 84. The ball studs 80 may be integral portions of the plate 24 or may be separate elements with the first ends 82a received in through holes 86. The second part 14 comprises a plate 40 having a relatively thicker central portion 42, with a central hole 44 extending therethrough. A termination block 46 is received in the hole 44. The termination block 46 comprises twelve spring loaded contacts 48 substantially aligned with, but protruding slightly from the front surface 20, each contact having a respective p.c. style surface mount termination 50 substantially aligned with, but protruding slightly from the rear surface 22 of the second part 14.

The second part 14 is typically mounted to a piece of electrical equipment, as represented by reference 60 in Fig. 10. The mounting may be via mounting screws (not shown) received in mounting holes 62 extending through the relatively thin outer portion of the plate 40.

Further through holes 64 are provided in the relatively thin outer portion of the plate 40. These through holes 64 are each in communication with a slot 66 at the respective side of the plate 40. A sprung clip 68 is received in each through hole 64, inserted via the associated slot 66. Each spring clip 68 is in the form of a planar portion 70 having a hole 72 therethrough, and a pair of sprung legs 74 symmetrically disposed on opposite sides of the through hole 72. The sprung legs 74 are generally S-shaped being connected to the planar portion 70 via a proximal bend

74a and having a distal bend 74b.

The ball studs 80 of the first part 12 and the respective sprung clips 68 of the second part 14 together comprise ball stud and clip fasteners. The first and second parts 12, 14 can be brought into mating connection by means of the interconnection of these ball stud and clip fasteners.

In use, when the first and second parts 12, 14 are brought together, the ball studs 80 projecting from the front surface 16 of the first part 12 and the associated clips 68 on the front surface 20 of the second part 14 are brought into engagement. Specifically, the head 84 of each ball stud 80 comes into contact with the sprung legs 74 of the associated clip 68 and as the relative movement of the first and second parts 12, 14 towards one another continues, the bulbous shape of the head 84, and specifically the top surface 84a thereof, causes a camming action on the S- shaped sprung legs 74, urging them apart to allow the head 84 to pass beyond the distal bends 74b. Once the widest portion of the head 84 has passed the distal bends 74b, the sprung legs 74 are urged back towards their initial position due to the resilience of the clip material. The distal bends 74b are thus then urged into engagement with the second end 82b of the stem 82, with the head 84 projecting past the distal bends 74b and being held securely, but releasably, in place.

In this engaged position, the respective first surfaces 16, 20 of the first and second parts 12, 14 are flush with one another, as best seen in Figs. 5 and 9.

An electrical connection is made across the first and second parts 12, 14 when mated by virtue of the contacts 32 in the first part 12 being brought into butting connection with the corresponding contacts 48 on the second part 14. Specifically, as the first and second parts 12, 14 are brought together and the head 84 of the fastener is urging the sprung legs 74 apart, the contacts 32 are brought into butting connection with the corresponding contacts 48. Further relative movement of the first and second parts 12, 14 towards one another urges the sprung contacts 48 to compress, thereby ensuring a reliable contact with the associated contacts 32.

The ball stud and clip fasteners allow the first and second parts 12, 14 to be disconnected by pulling on the cable 36, provided that the force on the cable has at least a component in the rearward direction perpendicular to the front surface 16 of the first part 12. In other words, a pull on the cable 36 in any direction relative to a centre line axis of the connector 10 up to an angle of 90 degrees will result in a separation force that will urge the first and second parts 12, 14 apart.

As a result of the separation force, the head 84 of each ball stud 80 is urged back against the sprung legs 74 of the associated clip 68. The bulbous shape of the underside 84b of the head 84 causes a camming action on the S-shaped sprung legs 74, urging them apart to allow the head 84 to pass back beyond the distal bends 74b. Once the widest portion of the head 84 has passed the distal bends 74b, the first and second parts 12, 14 become disconnected. The electrical connection across the two parts 12, 14 is also broken by the separation of the first and second parts 12, 14. Accordingly, and in contrast to prior arrangements including a separate latch, the arrangement of the at least one ball stud and clip fastener and the butting contacts is such that it is possible to make an electrical connection across the contacts without a separate mechanism for latching the first and second parts 12, 14 together.

The resilience of the sprung legs 74 of the clips 68 and the bulbous shape of the heads 84 of the ball studs 80 are selected so that the separation force must exceed a threshold before the first and second parts 12, 14 separate. This is to prevent unwanted separation due to, for example, minimal disturbance of the cable 36 and/or first part 12 or even due to the weight of the cable 36 and first part 12. A threshold separation force in the range of 15 to 25 Newtons has been found to be appropriate. At this level, the first and second parts 12, 14 become disconnected before any damage is caused to the electrical equipment to which the parts are connected. Moreover, the risk of tripping over the cable 36 is greatly reduced because the tension in the cable 36 caused by its inadvertent disturbance and that might otherwise cause a trip will be released by the separation of the first and second parts 12, 14.

The functions of making an electrical connection across the two parts 12, 14 and holding the two parts together are separated in this invention: electrical connection is made by virtue of the butting electrical contacts 32, 48, for which there is a zero separation force (or even a slight negative separation force, due to the spring loaded contacts 48); whereas mechanical releasable connection of the two parts 12, 14 is achieved by virtue of the ball stud and clip fasteners. Thus, it is possible to achieve an instant, clean and non-directional separation when the cable 36 is pulled.

By way of example, the connector should be capable of 2500 mating cycles; the twelve butting contacts should be rated at 1 amp; the connector should be protected against moisture ingress up to IP 54 level and would meet standard safety requirements.

It will be appreciated, however, that other combinations of contacts and other ratings would be possible. For example, the first and second parts 12, 14 may each comprise just a single electrical contact 32, 48. Moreover, it is not necessary for the butting contacts to be spring loaded. Although the invention has been described above in connection with having a pair of ball and stud clip fasteners, there may instead be one or more than two such fasteners. The invention has been described by reference to the first part 12 having the projecting studs 80 and the second part 14 having the receiving clips 68 and associated features. It is of course possible to transpose elements so that, for example, the studs 80 project from the second part 14 and the receiving clips 68 and associated features are located in the first part 12.

It is preferred that the cable 36 extends from the rear surface 18 of the first part 12, since this gives the best release properties and the greatest range of angles that would induce a separation force in the direction perpendicular to the respective first surfaces 16, 20 of the first and second parts 12, 14. However, the cable 36 could extend from the top, bottom, or either side of the first part 12.

The second part 14 is described as being attached to an electrical device 60. In this regard, 'electrical device' encompasses power supplies, including stand-alone devices and, for example, mains electricity supplies. However, the second part 14 could instead be attached to the end of another cable. It will be apparent to the skilled reader that the electrical connections at the rear surface 22 of the second part 14 will be dependent on the application. Thus, where the second part 14 is for connection to a mains supply, the connections will be different to those for connection to another cable (which connections could be crimp or solder terminations, akin to those of the termination block 30 of the first part 12).

From Figs 5 and 7 it can be seen that the front surfaces 16, 20 of the first and second parts 12, 14 are not planar but include complementary profiles. These features provide positive location and alignment and also ensure correct engagement of the first and second parts.

Claims

1. An electrical connector, comprising: a first part having a front surface and a rear surface; and a second part having a front surface and a rear surface, the first and second parts being interconnectable via a mating connection of the front surface of the first part with the front surface of the second part; wherein the mating connection is provided by means of at least one ball stud and clip fastener, the ball stud projecting from the front surface of one of the first and second parts and the associated clip being located on the front surface of the other of the first and second parts; and wherein an electrical connection is made across the first and second parts when mated by virtue of at least one contact in the first part being brought into butting connection with at least one corresponding contact on the second part.

2. The electrical connector of claim 1 , wherein the first and second parts each comprise multiple respective butting contacts.

3. The electrical connector of claim 1 or claim 2, wherein the butting contacts are spring loaded.

4. The electrical connector of claim 1 , 2 or 3, comprising multiple ball stud and clip fasteners.

5. The electrical connector of any preceding claim, wherein the first part comprises a cable.

6. The electrical connector of claim 5, wherein the cable extends from the rear surface of the first part.

7. The electrical connector of claim 5 or claim 6, wherein the first part further comprises solder or crimp terminations for the cable.

8. The electrical connector of claim 5, 6 or 7, wherein second part is attached to a device.

9. The electrical connector of claim 8, wherein the second part comprises a PC style connector having surface mount terminations.