COMPACT ELECTRICAL CONNECTION AND DISTRIBUTION SYSTEM FOR PLUGGABLE MODULAR DEVICES

Abstract: A unique system for packing and distributing electrical signals within an electrical machine is disclosed. Electrical distributing circuit conductors are pre-printed or pre-plated directly onto the inside surface of the machine covers. A pluggable edge connector (1) is provided for interfacing the plated electrical conductors with an electrical card to be inserted in slot (11). The connector is fitted with indepen­ dently switchable contacts such as two positions slider switches (12) which allow a pluggable electrical device or card to be electrically coupled with a respective pre-plated/­ pre-printed conductor or a discrete wire conductor (42). As a result, changes in the distributing system can be made without changing the plated lands pattern on the mahine covers, but just by adjusting position of the slider switched button.

Description: The present invention relates to the distribution of electrical signals within a machine or the like. A general prior art methodology used for packaging and distributing electrical signals, within electrical machines, consists of a circuit board upon which a plurality of circuits are placed. A plurality of edge connectors are used for electronically interfacing the circuits with other electronic components, such as modules. The circuit boards and attachments are mounted to the machine frames. Oftentimes electrical cables are used to complete the internal wiring of the machine. Covers are then placed on the machine frame. The covers hide the internals of the machine and provide a more aesthetic appearance. The prior art describes several types of connectors for connecting modules to circuit boards. For example, U.S. Patents 3,344,243; 3,475,657; 3,922,054; 4,266,839 and 4,386,815 disclose module connectors for interconnecting printed circuit conductors and input/output (I/O) pads of an edge-connected printed circuit board. Also FR-A-2260257 discloses a similar connector. U.S. Patent 4,203,642 exemplifies another type of prior art connector. The patent describes an adjustable card edge connector for electrically connecting a double-sided printed circuit card with discrete conductors. U.S. Patent 3,902,777 describes a connector block for electrically interconnecting a dual in-line plug module with the printed conductors on a substrate. It is therefore the object of the present invention to provide a more efficient system for distributing electrical signals within an electrical machine. It is another object of the present invention to provide a more efficient connector for interconnecting printed circuit electrical devices. It is still another object of the present invention to provide a unique methodology for distributing electrical signals within a machine. The unique methodology includes a distribution circuitry pre-printed or pre-plated onto the inside covers of the machine. Edge connectors are designed for snapping into the covers and to form an electrical interface between the pre-printed or pre-plated circuitry and pluggable electrical devices or cards. The edge connector is provided with independently switchable contacts which enable electrical communication between the pre-plated circuitry or the device and a non-printed electrical circuitry. The foregoing features and advantages of the invention will be more fully described in the accompanying drawings. Fig. 1 shows a schematic of an electrical distributing system according to the teaching of the present invention. Fig. 2 shows a pictorial view of an edge connector according to the teachings of the present invention. Fig. 3 shows a, cross-section of the electrical distributing system. Fig. 4 shows a slider switching device. Fig. 5 shows a schematic of an interface for electrically interconnecting the top and side covers of the machine. Fig. 1 shows a partial view of an electrical machine whose electrical system is prepared according to the teaching of the present invention. The machine covers comprise of bottom cover 16 and side members 32 and 34, respectively. Electrical circuitry of conductors identified by numeral 4 is pre-printed or pre-plated onto the inside surfaces of the machine. A circuit identified by numeral 4A which can be used as a jumper is also printed on the bottom surface of the machine. A plurality of retainer openings 2 are fabricated into bottom cover 16. As will be explained subsequently, the use of the retainer aperture is to seat the pluggable edge connector 1. In the figure the edge connector 1A is shown fitted into the opening. The edge connector 1 is shown displaced from the opening. A pair of beam latches, only one of which is shown and identified by numeral 3, are fabricated on each pluggable edge connector. The beam latches coact with the retainer openings to latch the connector firmly against the bottom cover 16. The electrical connection between the connector and the circuitry occurs directly beneath the connector within the area identified by numeral 5. Preferably, the remaining area external to area 5 is pre-coated with an electrical insulated flame-retardant material to prevent accidental shorting or potential shock hazards during machine operation and servicing. Once the insulation material has been deposited a metallized coating may be plated, flame sprayed, or vacuum metallized over it to prevent electromagnetic interference or radio frequency interference. Preferably, the contact area 5 is masked off prior to the metallization deposition. Still referring to Fig. 1, an elongated card guide 10 is snap fitted or molded into bottom cover 16. The upper extremity of the card guide is provided with a retainer seat identified by numeral 9. A card holder 7 is fitted with a snap latch 8. The snap latch 8 coacts with the retainer seat 9 to hold the electrical device 6 firmly into the edge connectors. It should be noted that the pluggable device 6 may be a printer, power supply, logic package, etc. For simplicity, the only pluggable device described in the figure is a printed circuit card with a plurality of printed circuit conductors 30 deposited on the edge of the card. In assembling the machine the pluggable edge connector 1 is snap latched into retainer aperture 2. The offset beam latches 3 hold the edge connector firmly against the bottom cover of the machine. The pluggable device 6 is then fitted into slot 11 of the pluggable edge connector. The snap latch 8 latches into retainer seat 9 and holds the card firmly into the connector. Fig. 2 shows an isometric view of the pluggable edge connector assembly. The connector assembly includes housing 1 with a slot 11. The slot serves as a receptacle for the pluggable device 6 (Fig. 1). The slot extends through the pluggable device from the top surface 36 to the bottom surface. As stated before, a pair of beam latches 3 are integrally molded on the bottom surface of the pluggable connector. The beam latches are snapped into retainer aperture 2 (Fig. 1) to hold the edge connector firmly against the bottom cover of the machine. Two rows of apertures identified by numerals 38 and 40, respectively, are integrally molded into the side of the housing. The aperture in each row is discrete and intersects the elongated slot. Each of the apertures in the top row 38 is fitted with a metal terminal contact 13 and functions as an electrical receptacle. An electrical conductive terminal 14 is crimped onto a conductive wire identified by numeral 15. The wire can then be plugged into the aperture and mates with the buried contact 13. The buried contact then mates with discrete card edge conductor 30, thereby enabling electrical communication between different electrical conductors. For example, in Fig. 2 electrical conductors 15 are shown plugged into respective apertures. Still referring to Fig. 2, the apertures in row 40 are each fitted with a slider switch 12. As will be explained subsequently, the slider switch is a two-position switch movable in the slide-direction shown in Fig. 3. When it is in one position, say the down position 50, as is demonstrated in Fig. 3, slider spring contact 17 is in contact with conductors 30 and 4, respectively. In this position the electrical device 6 is in electrical communication with the circuit on the inside covers of the machine. Similarly, when the switch is in the up position as is demonstrated by the switches at location 52 (Fig. 3), the electrical communication is broken with conductor 4. If one desires, the terminated electrical wire 15 can then be plugged into one of the discrete openings in row 38 to form an electrical communication between the pluggable device and some other device. As a result of this feature, wire changes can be made without changing the plated lands or conductor pattern on the machine cover. Referring to Fig. 4 for the moment, the details of the vertical slider switch are shown. The switch comprises of a plastic slider housing 54. Spring clip 19 protrudes from both sides of the slider housing. The function of the spring clip is to hold the switch firmly in one of its selected positions. A metal slider spring contact 17 is attached to the front surface of the plastic slider housing. The lower surface 56 of the metal slider spring contact 17 is fabricated with a slight bow. As will be explained subsequently, when the switch is in the down position (Fig. 3), the bow disappears and provides added pressure between the slider spring contact and the electrical land pattern on the bottom surface of the machine. Fig. 3 shows a cross section of the pluggable connector with a pluggable device therein attached to the bottom surface 16. The cross section is helpful in understanding the operation of the connector system. The connector housing/assembly 1 is snapped into the plastic bottom cover 16 and is retained by beam latches 3. The pluggable device 6 is plugged into the connector housing 1 and is self-aligned by means of a molded slot 11. The pluggable device is retained by the frictional engagement of the connector 1 and by the existing card latches previously described in Fig. 1. Two connection possibilities are provided. One of the connection possibilities is shown on the right-hand side of the pluggable device 6; the other is shown on the left-hand side. On the right-hand side the switch 12 is in the down position and a circuit conductor 4 disposed on the bottom surface 16 of the machine is in contact with an edge conductor on the card. As stated previously, the circuit conductor 4 is overcoated with an insulation material except in the area of contact with the slider contact 17. The slider switch 12 is held in the lower position with the metal spring 19 which engages into a detent 20. The bow which is fabricated in slider spring contact 17 disappears and as a result the electrical connection between the slider switch 17 and the conductor 4 is enhanced. It should also be noted that although the wire terminal 13 is always in contact with the card edge conductor 30 it is inoperative since it is not coupled to a wire or electrical conductor. In other words, the metal terminal contact 13 is always in contact with the card edge conductor 30. However, until a conducting wire is forced into one of the apertures 38 to make contact with the buried metal terminal contact 13 it remains inactive or inoperative. Still referring to Fig. 3, the other possibility occurs when the slider contact 12 is moved upwardly (direction of travel is shown by the slide direction 58). The second possibility is shown on the left-hand side of printed circuit card 6. The slider switch 12 is pushed to the upper position with the metal spring 19 engaging the upper detent 20. Moving the slider switch to its upper position breaks the connection between the circuit conductor 4 and the card conductor 30. It should be noted that when the slider switch is in the upper position the spring is in a relaxed state and the bow 56 appears. When the switch is in the inoperative position, a discrete electrical wire such as 15 can be placed into contact with the card edge connector 30. To achieve this connection the wire is inserted into one of the upper apertures 38 and the wire crimp terminal 14 is brought into contact with conductor 30 via the buried metal terminal contact 13. This electrically connects the terminated wire I5 to the card conductor 30. The terminated wire 15 is held in place by plastic retainer tab 22. The plastic retainer tab 22 is an integral part of the connector housing 1. The terminal 14 has two contact points 23 with the metal terminal 13. The terminated wire 15 can be removed by inserting a tool (not shown) and depressing the retainer tab 22 and pulling the wire I5 out of the connector housing 1. Fig. 5 is a schematic showing how a top cover 24 mates with bottom cover 16. As with the bottom and side covers a plurality of electrical circuits identified by numeral 4 are also deposited on the top inside surface of the machine cover 24. In order to bring these conductors into conductive contact a plastic connector 25 with a plurality of metal spring contacts 26 is mounted on bottom covers 16. In the preferred embodiment of this invention a plurality of space guide pin holes 28 are placed into the bottom cover 16. The plastic connector 25 is fabricated with a spacer section 29 and a plurality of space guide pins 27 mounted on the spacer section. In assembling a top cover the guide pins 27 are fitted into pin holes 28. The spacer member 29 forms a control opening between the conductors in the bottom member 16 and the metal spring contacts 26. Next the top cover 24 is simply assembled by mating notches on the top cover with notches on the bottom cover . The conductors 4 on the top cover 24 are automatically plugged into the control opening (that is a space formed by the connector 25 and the inside surface of the bottom cover 16). The metal spring on connector 25 bridges the conductors 4 on the bottom and top covers, thus completing the electrical circuit. There are several advantages when a machine is assembled according to the teaching of the present invention. Among the advantages are costly and bulky cable assemblies are eliminated by pre-printed or pre-plated circuitry. Also, eliminating cables and their associated part numbers greatly reduces the size and cost of a machine's billed structure. Electrical connection between the cover and the base is automatic upon assembling the two halves. As compared to standard pluggable cable connections which are subject to movement and wear vibration, the described invention has vibration-proof connections. Card or pluggable device polarization can be integrally molded into the card edge connector. Wiring or circuit changes or switching are easily made by moving the slider switch up and inserting the terminated wire into the pluggable edge connector. The pluggable device is aligned by integrally molded slots inside the pluggable edge connector and is securely retained by a conventional snap latch of the card holder. Conventional jumpers can be eliminated by pre-plating or pre-painting the jumpers on the inside surface of the machine.

Claims: A system for distributing electrical signals within an electrical machine comprising: a cover (16, 32, 34) operable for covering the internal components of said machine, with pre-printed and/or pre-plated distributing electrical circuitry (4) on the inside surface of the cover; an edgewise connecting means (1) operable for connecting to the cover and having an elongated slot (11) adapted to receive a pluggable device (6) having a plurality of edge conductors (30) thereon; discrete switching means (12) coupled to the edgewise connecting means (1) and operable to move between a first position whereat the pluggable device (6) is placed into electrical communication with the circuitry (7) and a second position whereat the electrical communication is discontinued, characterized in that said discrete switching means comprises: two rows (38, 40) of discrete apertures disposed on a side surface of the edgewise connecting means (1); a terminal contact means (13) disposed in each aperture of a first row (38) in electrical contact with the corresponding edge conductor (30), and adapted to receive a wire terminal (14) connected to a conductive wire (15); and a two positions slider switch (12) disposed in each aperture of the second row (40) provided with a spring clip contact (17) that is permanently in electrical contact with the corresponding edge conductor (30) and with said circuitry (4) only in a determined position of said switch. The system of claim 1 further including a guide rail connected to the cover (16, 32, 34) and operable for positioning the pluggable devices(6)relative to pre-selected zones on the covers. The system recited in claim 2 further including holding means (78) operable for coacting with the guide rails (10) to hold the device (6) firmly in place.

Inventors: PASTERCHICK, HARRY, JR., TURNER, CRAIG WALTON
Applicants: INTERNATIONAL BUSINESS MACHINES CORPORATION
Application year: 1985
Main classification: H01R23
IPC codes: H01R13, H05K1, H05K7, H01R12, H01R29