GB2157223A

GB2157223A - Hand tool extraction of electronic components from sockets

Info

Publication number: GB2157223A
Application number: GB08407129A
Authority: GB
Inventors: Martin John Weston
Original assignee: TALLORD Ltd
Current assignee: TALLORD Ltd
Priority date: 1984-03-19
Filing date: 1984-03-19
Publication date: 1985-10-23
Also published as: GB2157223B; GB8407129D0

Abstract

The hand tool comprises a pair of jaws (9) movable towards each other against a spring bias (10) to engage the underside of a component (1) by means of opposed projections (11). Lever arms (12) engage the top side of the component (1) so as to clamp the component (1) between the jaws (9) and the arms (12) and so facilitate extraction of the component (1). <IMAGE>

Description

SPECIFICATION Hand tool for extraction of electronic components from sockets The present invention relates to a hand tool for extracting electronic components from sockets.

Most modern electronic circuits comprise relatively few components mounted on a board usually of plastics material. These components are standard, mass produced, complex sub-circuits fabricated on a single "chip" of silicon.

The "silicon chips" are supplied encased in a package of plastics or ceramic material, the electrical connections to the chip being made via rows of metal pins spaced at 0.1 inch intervals along two opposite sides of the package. Interconnections between packages are made by means of copper tracks on one or both side of the plastics board.

The most common method of mounting packages is to pass the pins through holes in the plastics board and solder direct to the tracks.

For some types of component it is more desirable to solder a socket in the board into which the package may be plugged, each pin of the package being retained by a spring loaded contact.

A package commonly used in microprocessors based electronic circuits is a multi-pin E.P.R.O.M.

(Erasable Programmable Read Only Memory), the function of which is to hold the sequence of instructions (PROGRAM) upon which the microprocesssor operates. Thus the operating characteristics of a microprocessor based system may be modified or changed completely merely by substituting "PROMS" loaded with one set of instructions with "PROMS" containing a different program. A "PROM" may be re-used many times by exposing the window to ultra violet light, to erase the existing program, and reprogramming on a a special machine.

The number of times a "PROM" may be re-used is more often limited by physical damage to the pins, at the time of extraction from the socket, than by electrical failure. The most popular method of removing a PROM is to lever it out with a screwdriver or similar tool thus risking damage not only to the component and socket but also to other delicate components in the vicinity.

An object of the present invention is to provide a tool suitable for removing such a component with ease and without damaging the component, the socket from which it is removed, or other components, e.g. the circuit board on which the socket is mounted.

The invention provides a hand tool for extracting an electronic component from a socket comprising a pair of jaws movable towards each other against a spring bias to engage the underside of the component, and arms for engaging the topside of the component so as to clamp the component between the jaws and the arms and facilitate extraction of the component.

Preferably, the arms are arranged so that, on engagement of the component by the jaws and on further movement of the jaws towards each other, the arms incline downwards to engage the topside of the component.

An embodiment of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of a typical electronic component and socket; Figure 2 is a perspective view of the hand tool in accordance with the invention; Figures 3 to 5 are front views of the hand tool of Fig. 2 at different stages during removal of an electronic component from a package; and Figure 6 is a side view of the hand tool of Fig. 5 at the final stage of removal of the electronic cornponent.

Fig. 1 shows a typical electronic component 1 in the form of an EPROM comprising a plastics or ceramic package 2 housing a silicon chip (not shown). The package 2 has a window 3 and twenty-four pins 4 for making electrical connections to the silicon chip.

A plastics socket 5 is soldered to connectors 6 mounted in a plastics circuit board 7 and has twenty four metal inserts 8 containing springloaded contacts engageable by the pins 4 of the component 1.

A hand tool suitable for removing the component 1 from the socket 5 comprises two jaws 9 interconnected by a spring member 10. The jaws 9 and spring member 10 may be made from a single, horse-shoe shaped, strip of e.g. plastics or metal. The jaws 9 comprises two elongate legs 11 provided with opposing projections 11' for engaging the underside of the component 1, and rigid lever arms 12 are fixed to the legs 11 for engaging the topside of the component 1. The arms 12 have inter-engaging ends 13 limiting the moving apart of the jaws 9 under the action of the spring member 10.

The hand tool is operated as follows: The tool is held in one hand, the straight jaws 9 being held by thumb and forefinger as indicated by arrows 14, and the half round portion of the spring member 10 resting in the palm of the hand as shown in Fig. 3.

The tool is manouvered from the position shown in Fig. 3, into the position shown in Fig. 4, by slight pressure between thumb and forefinger, the projections 11' of the jaws 9 locating in the gaps between the component 1 and the socket 5.

Further pressure between thumb and forefinger distorts the spring member 10 such that the lever arms 12 rest on the top of the component 1. Increasing the pressure in the areas indicated by arrows 14 inclines the lever arms 12 downwards and securely clamps the component 1 between the lever arms 12 and the projections 11' of the jaws 9 as shown in Fig. 5.

The component 1 may now be removed by applying a steady pull in the direction of arrow 15 combined with a slight rocking action, whilst maintaining the pressure between thumb and forefinger, as illustrated in Fig. 6.

The advantages of the above-described embodiment over any other known method of component removal are as follows: a) elimination of damage to the PROM socket (especially the spacer bars between the two rows of contacts); b) elimination of distortion of the socket contacts andlor connection pins of the component by unequal lifting at one end of the package; c) increase in the speed and confidence of component removal; d) elimination of damage, or probably more importantly, the suspicion of damage, to other delicate components in the close proximity of the component ahd socket. The suspicion of damage would lead to time-consuming and costly testing of the complete printed circuit board on which the component and socket are mounted.

Various modifications may be made to the tool within the scope of the invention as claimed. Thus, the tool could be powered to provide fast repetitive separation of components from sockets.

Claims

1. A hand tool for extracting an electronic component from a socket comprising a pair of jaws movable towards each other against a spring bias to engage the underside of the component, and arms for engaging the topside of the component so as to clamp the component between the jaws and the arms and facilitate extraction of the component.

2. A hand tool as claimed in claim 1, wherein the jaws comprise two elongate members interconnected by a curved resilient member.

3. A hand tool as claimed in claim 2, wherein the elongate members and curved member are formed from a resilient strip.

4. A hand tool as claimed in claim 2 or 3, wherein the ends of the elongate members remote from the curved member have opposed projections for engaging the underside of the component.

5. A hand tool as claimed in any one of the preceding claims, wherein the arms have inter-engaging portions to limit moving of the jaws.

6. A hand tool as claimed in any one of the preceding claims, wherein the arms are arranged so that, on engagement of the component by the and on further movement of the jaws towards each other, the arms incline downwards to engage the topside of the component.

7. A hand tool as claimed in any one of the preceding claims and powered to facilitate repetitive extraction of components from sockets.

8. A hand tool substantially as herein described with reference to the embodiment shown in the attached drawings.

9. A method of extracting an electronic compo nent from a socket comprising engaging the un derside of the component by means of opposing jaws of a hand tool, resiliently deforming the jaws of the hand tool until arms on the jaws engage the topside of the component so as to clamp the com ponent between the jaws and the arms, and pull ing the tool to extract the component.