GB2312331A

GB2312331A - Overmolded electrical components

Info

Publication number: GB2312331A
Application number: GB9707297A
Authority: GB
Inventors: Hollis Paul Raymond; Daniel Lee Gorenc
Original assignee: Whitaker LLC
Current assignee: Whitaker LLC
Priority date: 1996-04-16
Filing date: 1997-04-10
Publication date: 1997-10-22
Also published as: DE19715673A1; GB9707297D0; JPH1050452A

Description

2312331 OVERMOLDED ELECTRICAL COMPONENTS The invention relates to an

assembly of discrete electrical components which are held in fixed relative 5 positions, and to a method of making the assembly.

Many electrical components are attached to a circuit board by soldering. Each component which is to be soldered must be properly positioned on the circuit board so that contacts of the component are in registration with corresponding pads or terminals on the board prior to soldering. Due to miniaturization of electronic components, the pads on the board are being made smaller, and precise alignment of electrical components with respect to each other is becoming more critical. Additionally, a circuit board may contain a multitude of discrete electrical components which are individually mounted to the board. Even automated assembly equipment commonly utilizes a pick and place assembly method wherein each component is individually placed on a board. This method requires a large number of machine movements and is therefore relatively timeconsuming and inefficient. Further, positional tolerance stack-up during multiple operations decreases the positional accuracy of components placed on the 25 board. The problem to be solved by the invention is how to reduce assembly time and tolerance stack-up when mounting a plurality of electrical components on a circuit board. 30 The invention solves this problem by providing an assembly of electrical components which can be mounted on a circuit board in a single operation. The assembly comprises at least two discrete electrical components and an overmolded frame which is connected to hold the components in fixed relative positions.

In one embodiment the electrical components are spaced-apart, and the frame includes two spaced-apart parallel frame members each spanning a distance between the components. The components are aligned parallel to each other along respective axes that extend perpendicular to the parallel frame members. The frame may also include a link member connected between the frame members, and the link member may have a pad configured to be engaged by pick and place assembly equipment. Further, the components may have T-shaped slots with the overmolded frame having portions molded within each of the slots.

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

Fig. 1 is a top plan view of an assembly according to the invention; Fig. 2 is a front view of the assembly; Fig. 3 is bottom view of the assembly; Fig. 4 is a side view of the assembly; Fig. 5 is a top view of an overmolded frame which is part of the assembly; and Fig. 6 is a top view of electrical components which are part of the assembly.

An assembly of electrical components as shown in Figs. 1-4 comprises at least two discrete electrical components 10 which are connected together by an overmolded frame 20. As shown more clearly in Fig. 6, each of the components 10 is an independent electrical device which can be individually terminated to a mating electrical connector or a substrate. The components 10 which are shown in the drawings are Metristak connectors which are sold by AMP Incorporated of Harrisburg, Pennsylvania, USA, and these are generally applied to a circuit board. Each of these Metristak connectors has a plurality of terminals 8 arrayed in two rows. The terminals 8 are of the surface mount type which can be soldered to a corresponding array of pads on a circuit board substrate. Although Metristak connectors are shown, it should be understood that the invention may be practiced with other varietiES of components 10 which are suitable for interconnection with a mating connector or a substrate.

When the components 10 are to be mounted at fixed positions with respect to each other, for example on a circuit board, a significant reduction in assembly time and cost can be achieved by providing the components 10 as an assembly which can be handled as a single part rather than two or more parts. The frame 20, shown in Fig. 5, is overmolded on the components 10 to hold the components in fixed relative positions as an assembly. These positions are selected according to the intended relative positions of the components 10 on the circuit board. Although the frame 20 is shown in Fig. 5 as a separate unit for clarity, the frame 20 is overmolded on the components 10 and is not formed separately.

The overmolded frame 20 can be formed in a suitable molding machine using known overmolding techniques. The overmolded frame must be firmly attached to the components 10 so that it does not separate from the components during handling. In order to ensure firm attachment, the frame can be molded with retention portions 28 extending into one or more recesses 16 in the components 10. The illustrated Metristak connectors each have a pair of recesses 16 in the form of T-shaped slots on respective opposite ends of the connectors. These slots were originally intended for use with a mechanical holddown device for locating and positioning the Metristak connectors on a circuit board, and these slots are standardized on a full line of Metristak connectors having different numbers of the terminals 8. These slots have now been advantageously employed as the recesses 16 for receiving the retention portions 28 of the overmolded frame. By using these standardized slots, the overmolded frame 20 can be easily modified in size for connectors with different numbers of terminals, 5 or to accept additional components 10.

In a preferred embodiment the components 10 are spaced-apart and the overmolded frame 20 includes two parallel frame members 22 which span a distance between the components. The components 10 are aligned with their longitudinal axes parallel to each other and perpendicular to the frame members 22. The frame 20 includes a link member 24 connected between the frame members 22 and positioned in a space between the components 10.

is A means for gripping the component assembly may be provided by an enlarged pad 26 which is centrally disposed on the link 24. The pad 26 is suitable for engagement by pick and place assembly machinery of the type which utilizes a vacuum tube to pick up individual components by suction. Alternatively, the means for gripping may be provided by a molded projection which configured to be grasped by mechanical grippers.

Alignment pins are formed on an underside of the overmolded frame. Alignment pin 32 of one size and alignment pins 34 of a different size are insertable in respective holes in a circuit board when the assembly is properly aligned with the board.

The invention provides a component assembly wherein multiple components are held in fixed positions with respect to each other. The multiple component assembly can be mounted on a circuit board with a lesser number of operations than would be required to mount the components individually. The assembly also simplifies the placement of multiple components on a circuit board by reducing the stack-up of positional tolerances.

Claims

1. An assembly of electrical components comprising:

at least two discrete electrical components; and an overmolded frame connected to hold the at least two components in fixed relative positions.

2. The assembly according to claim 1, wherein the at least two components are spaced-apart, and the overmolded frame includes two spaced-apart parallel frame members each spanning a distance between the at least two components.

3. The assembly according to claim 2, wherein the at least two components are aligned parallel to each other along respective axes that extend perpendicular to the parallel frame members.

4. The assembly according to claim 2 or 3, wherein the overmolded frame includes a link member connected between the parallel frame members.

5. The assembly according to claim 1, 2, 3 or 4, wherein the overmolded frame includes at leastone-pad or aprerjection configured for engagement by pick and place assembly equipment.

6. The assembly according to claim 5, wherein the at least one pad or projection is-dentrally disposed on the frame.

7. The assembly according to any preceding claim, wherein each of the components defines a slot, and the overmolded frame includes respective portions molded within each of the slots.

8. The assembly according to any preceding claim, wherein the overmolded frame includes at least one alignment pin which is insertable in a respective hole in a circuit board. 5

9. A method of making an electrical component assembly comprising the steps of:

providing at least two discrete electrical components; arraying the at least two components in selected relative positions; and overmolding a frame on the at least two components to fix the components in said selected relative positions.

10. A method of making an electrical component assembly, substantially as hereinbefore described with reference to the accompanying drawings.

11i An assembly of electrical components constructed and arranged substantially as--hereinbefore described with reference to the accompanying drawings.