MOUNTING ELECTRICAL COMPONENTSThis invention relates to a method for the mounting of electrical components on a panel, and to a panel arranged for such mounting. The invention is particularly, but not exclusively, concerned with the mounting of switches and the like to a motor vehicle instrument panel.
An instrument panel for a motor vehicle conventionally has components such as switches mounted on its front face and connected at the rear face of the panel to appropriate wires of an electrical wiring loom. The manner in which the switches are connected to the wires and to the instrument panel varies, but typically terminals on the ends of the wires are passed through a hole in the instrument panel, are connected to the back of the switch, and the wires are then fed back through the hole with the switch approaching the front face of the panel where it is clipped into place. This requires that the wires used to feed current to the instrument panel switches and other components be over-length because they have to be long enough to be passed through the panel and connected to the switch before being fed back through the hole in the panel.
According to the present invention, there is provided a method of mounting an item, to which electrical connections must be made, to a front face of a panel, the method comprising the steps of making a hole through the panel, providing rearwardly extending walls around the hole on the rear face of the panel, connecting a terminal fitting on the end of a wiring loom to the rearwardly extending walls in a position such that the terminals of the fitting are exposed through the hole, and plugging the item to which electrical connections must be made into the hole so that electrical contact is made between the electrical connections of the item and the terminals of the fitting.
Preferably the terminal fitting is snap-fitted into the rearwardly extending walls, in a manner which resists subsequent withdrawal of the fitting. Preferably also the item is snap-fitted through the hole into the rearwardly extending walls.
The panel may be an instrument panel for a motor vehicle, and the item may be a switch or the like electrically connected instrument panel component.
The invention also provides a panel having a hole therethrough through which electrical connections to an item to be mounted on the panel front face can be made, rearwardly extending walls on the rear face of the panel around the hole and means for engaging a terminal fitting of a wiring loom to the rearwardly extending wall.
The panel may be an instrument panel for a motor vehicle.
The rearwardly extending walls may surround the entire circumference of the hole or part of the circumference of the hole. In a preferred embodiment, the walls define a tubular, possibly rectangular, socket, with windows through side faces thereof in which a terminal fitting and/or part of the item can be secured.
The terminal fitting may have an abutment which limits insertion movement of the terminal fitting into the rearwardly extending walls.
The terminal fitting and/or the item may have tapered adjoining end faces which fit one inside the other.
The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:Figure 1 is a diagrammatic view showing the rearface of an instrument panel and indicating howconnections are made to the rear face;Figure 2 is a view similar to Figure 1 but showingconnections being made to the front face of theinstrument panel; andFigure 3 shows a cross-section through an instrumentpanel with an item fitted thereto.
Figure 1 shows a scrap section 10 of an instrument panel viewed from the rearside 12 thereof. In this embodiment the instrument panel is moulded with a recess 13 on the front face which appears as a raised area 14 on the rear face, and four rearwardly extending walls 16 which define a box-like socket 18. The socket 18 is open at the rear, as can be seen in Figure 1, and also at the front face as can be seen particularly in Figure 3. The socket 18 also has windows 20 along its side walls. The socket does not however have to be rectangular in form. The socket could be circular (with a key-way to ensure correct orientation), triangular, oval or of any other suitable shape.
A switch or other instrument panel component is to be mounted to the front face of the panel 10, and an electrical connection is to be made to that component from the rear face of the panel 10. In the remainder of this description, the component will be described as a switch.
The electrical connections are made from a wiring loom 22 which includes a number of individual wires 24 connected into a connector plug 26 in a known way. The front face of the connector plug 26 (not visible in the drawings) will have a number of female terminals, preferably arranged in a regular array across the front face.
In assembling the switch to the instrument panel, the connector plug 26 is introduced into the rear end of the socket 18, as indicated by an arrow 28. The connector plug has resilient lugs 30 on its side faces and stop pins 32 on its top and bottom faces. When the plug is pushed into the socket 18, the resilient lugs 30 will yield to allow entry of the plug into the socket but will snap out when they come to register with the rearmost pair of windows 20 in the wall 16. At this position also the stop pins 32 will abut the rearmost edges of the top and bottom walls of the socket 18. The plug is therefore reliably held in position in the socket 18. It cannot be inserted any further because of the stop pins 32 and it cannot be withdrawn because of the engagement of the lugs 30 in the windows 20. This position is shown in the left hand part of Figure 2.
At this stage, the front face of the instrument panel presents a female socket into which a male component can be plugged.
A switch module 34 is shown in Figure 2. This module has an oval bezel 36 which will fit within the recess 13 (seeFigure 3) on the front face of the panel. The module 34 has a rearwardly extending connector block 38 designed to enter the socket 18 from the front face of the panel. The block 38 has lateral resilient lugs 40 which, like the lugs 30, snap into the, so far unoccupied, forwardmost pair of windows 20 of the socket 18. The block 38 also has male terminals 42 which will engage with the female terminals in the connector plug 26.
The final stage in assembly of the instrument panel is therefore simply to push in the switch module 34 from the front face of the preassembled instrument panel in the direction of the arrow 37 until it engages with the socket 18 and the connector plug 26, as shown in Figure 3.
When the module 34 is plugged in, a rearward load will be exerted on the connector plug 26, and Figure 3 shows how the resilient lugs 30 of the connector have inwardly turned ends 44 to resist these forces.
Figure 3 also shows that the rearward facing block 38 of the switch module 34 has a skirt 46 which engages within a flange 48 of the plug 26, to ensure correct alignment of the male and female terminals 42 on final assembly.
The leading edge (rearward facing) of the skirt 46 has a chamfer 50 to aid alignment.
All the components described can be made of suitable plastics materials, with the exception of the parts which actually carry electrical current. The front face of the switch module can be designed as desired to give a required aesthetic appearance. The manner in which the switch operates (whether it be a toggle switch or a push switch) does not form part of this invention.
It will be clear that although the invention has been described here particularly with reference to a switch as the component being fitted to the instrument panel, the invention is equally applicable to other components to be mounted on any panel.
Ideally the walls 16 forming the socket 18 will be moulded integrally with the main instrument panel 10. However, in certain circumstances this may not be possible for technical reasons and in such a case the panel may be moulded simply with a hole therethrough, and a separate socket 18 can be subsequently mounted on the rear face of the panel before the assembly operation as described above.
It will also be apparent that the socket 18 into which the connector plug is inserted does not have to be defined by continuous walls 16 surrounding the hole through the panel.
It will be noted from Figure 3 that the plug 26 and the block 38 are not tight fits within the socket 18. It is advantageous to allow these two components to float to some extent to enable them to align with each other correctly before electrical connection is made.