BACKGROUND TO THE INVENTION Electric switches are used to effect an electrical connection between two points to provide electric power from a source to a load. The main elements of an electric switch are: the terminals which provide positive and negative contact points, a bridge to provide electrical connection between the two terminals to allow electricity to flow, a switch mechanism to allow an external user to actuate the bridge to make and break contact with the terminals to open and close the switch respectively, and an insulated body to contain all of these parts.

In conventional switches, (see Figures 1A and 1B) the base of the bridge 30 is electrically connected to one terminal (not shown) by electrically connecting a point 40 about which the base pivots to the terminal. A contact point 31 on the bridge 30 is caused to make and break contact with the other terminal 50. Thus, to turn the switch on, the bridge 30 is caused to pivot about its base to make contact with one of the terminals 50 of the switch. Since the bridge 30 is electrically conductive, this closes the circuit between the two terminals, the one terminal 50 having contact with the contact point 31 of the bridge and the other terminal being electrically connected to the base of the bridge 30 about which the bridge 30 pivots. Thus, a closed circuit is created allowing electricity to flow. To turn the switch off, the bridge 30 is caused to pull away from the terminal 50 by pivoting it about its base which remains in contact with its pivot point 40 which remains electrically connected to the other terminal.

This arrangement suffers from a number of disadvantages including the requirement for additional components to connect the pivot point 40 of the base of the bridge 30 to one of the terminals, resulting in increased component costs to the switch as well as assembly time. Furthermore, the electrical contact between the bridge and pivot point can cause arcing which increases the rate of wear.

This problem has been addressed in the past by providing a bridge which is not electrically connected to the pivot point 40, and which has instead, two terminal contact points for electrically connecting with respective switch terminals. In this arrangement however, difficulties arise in ensuring that the two contact points make approximately simultaneous contact with their respective terminals. Furthermore, it is difficult to ensure that contact points contact their respective terminals with even pressure. Contacting at different times and with uneven pressures can result in arcing and increased wear to the components.

Accordingly it is an object of the present invention to provide an electric switch and a bridging arrangement which provides a more efficient contacting action.

Another aspect to consider is in the construction of conventional electric switches, the terminals and bridge are inserted and assembled in the switch casing from an open top portion of the casing and enclosed therein by fixing the switch actuator at the top of the casing. In use, the terminals will rest against a floor portion of the casing and will be supported thereby throughout the life of the switch. This contributes a significant amount of time and complexity in installing and securing the terminals to the casing, adding to increased manufacturing costs.

Figure 5 shows an exploded view of the conventional means of inserting components, including terminals into a switch casing.

It is an object of the other aspect of the present invention to provide a means of facilitating the insertion of terminals into the switch casing.

BRIEF DESCRIPTION OF THE INVENTION According to a first aspect of the present invention, there is provided a bridge for an electric switch having at least two terminals, the bridge including at least two contact members for making electrical contact with respective terminals of the switch, wherein the at least two contact members are resiliently flexible to allow even pressure to be exerted on the respective terminals upon making contact.

Preferably, the at least two contact members make electrical contact with the respective terminals at substantially the same time.

The resiliently flexible contact members will preferably be formed by respective fingers extending from a main body portion. The fingers may terminate in pads that are raised above a plane defined by the main body portion.

According to a second aspect of the present invention, there is provided an electric switch having at least two terminals, a bridge according to the first aspect of the present invention and a base having a cradle portion being electrically insulated from the at least two terminals and allowing the bridge to pivot between a first position and a second position to turn the switch on and off.

According to a third aspect of the present invention, there is provided a bridge for an electric switch having at least two terminals, the bridge including at least one contact member for making electrical contact with at least one of the terminals, wherein the contact member is resiliently flexible.

According to a fourth aspect of the present invention, there is provided a casing for an electric switch, the casing having an outer wall defining a top for receiving a switch actuator, and a bottom end, distal to the top, wherein the bottom end includes a recess for receiving a terminal, allowing the terminal to be inserted from said bottom end.

Preferably, the outer wall surrounding the recess includes a keyhole-shaped entry slot for receiving a screw which secures the terminal to the outer wall when received in said recess.

BRIEF DESCRIPTION OF THE DRAWINGS Figure la shows a conventional bridge/terminal arrangement of the prior art in an open circuit state; Figure 1b shows a conventional prior art bridge/terminal arrangement in a closed circuit state; Figure 2a shows a plan view of a preferred bridge configuration in accordance with the present invention; Figure 2b shows a side view of a preferred bridge configuration in accordance with the present invention; Figure 2c shows a perspective view of a preferred bridge configuration in accordance with the present invention; Figure 3a shows the bridge of Figures 2a to c in place in an electric switch according to the present invention in an open circuit state; Figure 3b shows the bridge of Figures 2a to c in an electric switch according to the present invention in a closed circuit state; and Figure 4 shows an exploded view of the components of an electric switch according to a preferred embodiment of the present invention.

Figure 5-shows an exploded view of the components and method of assembling the components according to the prior art; Figure 6-shows a side view of the electric switch according to the present invention; Figure 7-shows a front view of the electric switch of Figure 2; Figure 8-shows a perspective view of the electric switch of Figure 2; Figure 9-shows a perspective view of the electric switch of Figure 2 with the terminals inserted; and Figure 10-shows a side cross sectional view of the electric switch of Figure 2 with the terminal inserted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Figures 2a to 2c show various views of a preferred configuration of the bridge 10 of the present invention. Bridge 10 consists of a main body 11 and two fingers 12 and 13 extending from the main body. Fingers 12 and 13 end in raised pads 14 and 15. These pads 14,15 are formed by simply shaping the ends of fingers 12 and 13 respectively to provide a portion which extends beyond a plane defined by main body 11 as can be seen clearly in Figure 2b.

Bridge 10 can be made of any suitable electrically conductive material as will be understood by the person skilled in the art and may take on any shape which allows the bridge to perform in accordance with the present invention.

Fingers 12 and 13 with corresponding pads 14 and 15 will flex backwards (to the left when viewed in Figure 2b) when pressure is applied upon the pads 14 and 15 however, the fingers 12,13 and pads 14,15 will be continually biased towards the source of the force thereby providing a more efficient contact.

The provision of resiliently flexible fingers 12,13 and pads 14,15 dramatically enhance the operation of the switching action by facilitating smooth and even pressure being applied to both terminals at the same time. In this configuration, the bridge is essentially self-aligning as the fingers 12,13 flex to allow each pad 14,15 to touch its opposing terminal pad with even pressure.

It will also be understood that in a different aspect of the present invention, the bridge may be a conventional bridge (ie having only one contact/terminal point), but that this point may be resiliently flexible. It is again, this flexible resilience which assists in providing a smooth contact action between the contact point and the terminal.

Most electrical switches have silver contacts to ensure a good electrical connection however, over time with wear, the silver contact becomes worn away. The use of the resiliently flexible fingers 12, 13 ensures that good and even electrical contact is made with the terminals. This improves the resiliency of the switch to wear over time.

The action of bridge 10 within an electric switch 20 is shown in Figures 3a and 3b. As can be seen from these Figures, the body of switch 20 forms a cradle 22 which supports bridge 10. Bridge 10 in fact can simply rest at the bottom of cradle 22 and need not be connected in any way. In Figure 3a, bridge 10 is shown in the off position, being out of contact of terminal 21. To turn switch 20 on, bridge 10 is caused to pivot about its base in cradle 22 such that pads 14 and 15 (not shown) make contact with terminal 21 (and the respective terminal for pad 15-not shown). The pivoting of bridge 10 is effected by an externally applied force via a switch button for example (not shown).

The situation when bridge 10 has made contact with terminal 21 is shown in Figure 3b. It will be noted that pad 14 is flexed below a plane defined by the main body of bridge 10 due to the forward pressure created by terminal 21. A similar effect occurs to pad 15 (not shown) by its corresponding terminal (not shown). As previously discussed, this flexing allows each pad to make smooth and equal contact with their respective terminals.

A further advantage of the present invention is that because it is not necessary to connect the base of bridge 10 to one of the terminals, this results in a reduction in parts necessary to construct the switch 20 and accordingly a reduction in cost and assembly time.

An exploded view of a switch 20 according to the present invention is shown in Figure 4. There are effectively only three components required, being the body 23 of switch 20, bridge 10 (with associated spring 40) and dolly switch member 50.

Referring now to a different aspect of the present invention, as shown in Figure 6, electric switch 20 consists of main body casing 23, switch actuator 50 and terminal 21 with associated screw 24.

Figure 7 shows a front view of the switch of Figure 6 which also shows recesses 25 and 25'and terminals 21 and 21'with associated screws 24 and 24'.

As can be seen more clearly in Figure 8, the casing 23 around recesses 25 and 25' define two keyhole apertures 26 and 26', which receive screws 24 and 24' respectively.

Upon inserting terminals 21 and 21'into switch 20, the terminals are inserted into recesses 25 and 25'respectively with associated screws 24 and 24'partially engaging their respective terminals. As terminals 21 and 21'are inserted upwards into recesses 25 and 25', associated screws 24 and 24'are received in keyhole apertures 26 and 26'.

Terminals 21 and 21'are slid into recesses 25 and 25'until associated screws 24 and 24'engage the upper portion of keyhole apertures 26 and 26'. In this position, screws 24 and 24'have pushed past the top of the keyhole section where the slot is narrower, and thereby retain terminals 21 and 21'within switch casing 23.

As can be seen in Figure 9, the keyhole apertures 26 and 26'provide significant support around screws 24 and 24'to retain terminals 21 and 21'within electric switch 20. The gradually tapering entry of keyhole apertures 26 and 26', allow for relatively easy insertion of the terminals 21 and 21'into electric switch 20 however, once secured in the upper portion of keyhole apertures 26 and 26', it is far more difficult for terminals 21 and 21'and associated screws to be displaced from their positions within electric switch 20. This allows for a far more simple and efficient insertion and retention procedure for the terminals.

Figure 10 shows a cut-away view of terminal 21 and associated screw 24 in place in recess 25 with screw 24 being received in keyhole aperture 26. In this position, terminal 21 can engage electrically conducting bridge element 10 which provides electrical connection between terminals 21 and 21' (not shown) when electric switch 20 is turned on.

It will be understood that the above has been described with reference to particular embodiments and that many variations and modifications may be made within the concept of the present invention.