US3577113A

US3577113A - Electronics card extractor

Info

Publication number: US3577113A
Application number: US764483*[A
Authority: US
Inventors: Robert Thomas Maitland
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1969-10-02
Filing date: 1969-10-02
Publication date: 1971-05-04
Anticipated expiration: 1988-05-04

Abstract

An electronics card extractor utilized in the insertion and extraction of circuit cards from a card holder or electronics box having guiding elements or card slides secured at opposite sides of the box and extractors pivotally mounted at opposite outer corners of the card, the extractor being operative by a handle to cause projecting end portions of both extractors to simultaneously bear upon opposite reinforced upper edge portions of the card holder which in effect become fulcrums about which the force applied to the handle may initially provide an extraction force to effect a full disengagement of a card connector at a lower edge of the card from a connector mounted on the lower surface of the box, and thereafter upon the operator continuing to raise the handle the extractors then function to withdraw the card from the card holder, the extracting and card withdrawing forces being applied in sequence in one smooth upward motion.

Description

United States Patent [72] Inventor Robert Thomas Maitland Franklin Lakes, N ..I [21 Appl. No. 764,483 [22] Filed Oct.2, 1968 [45] Patented May 4, 1971 [73] Assignee The Bendix Corporation [54] ELECTRONICS CARD EXTRACTOR 4 Claims, 6 Drawing Figs. [52] U.S. Cl 339/17, 339/45, 339/46 [51] lnt.Cl ..H0lr 13/62, H05k 5/02 [50] Field ofSearch 339/17 (L,M), 45, 46; 292/93; 74/(lnquire) [56] References Cited UNITED STATES PATENTS 2,695,1 12 1 1/1954 Bonnevay ..(206/46 Fragile) 3,335,386 8/1967 Upton r 339/17(L) 3,476,258 1 1/1969 Dorsett 339/45(M) 2,402,935 6/1946 l-leffner et a1 292/93 3,008,115 11/1961 Oakes 339/45 3,181,906 5/1965 De Rose et al 339/45(M) 3,453,586 7/1969 Brendlen,.lr. 339/45(M) 3,476,258 11/1969 Dorsett 339/45(M) FOREIGN PATENTS 234,915 7/1961 Australia 339/45(M) Primary Examiner-Marvin A. Champion Assistant Examiner-Terrell P. Lewis Attorneys-Herbert L. Davis and Flame, Hartz, Smith and Thompson ABSTRACT: An electronics card extractor utilized in the insertion and extraction of circuit cards from a card holder or electronics box having guiding elements or card slides secured at opposite sides of the box and extractors pivotally mounted at opposite outer corners of the card, the extractor being operative by a handle to cause projecting end portions of both extractors to simultaneously bear upon opposite reinforced upper edge portions of the card holder which in effect become fulcrums about which the force applied to the handle may initially provide an extraction force to effect a full disengagement of a card connector at a lower edge of the card from a connector mounted on the lower surface of the box, and thereafter upon the operator continuing to raise the handle the extractors then function to withdraw the card from the card holder, the extracting and card withdrawing forces being applied in sequence in one smooth upward motion.

PATENTED MAY 41971 SHEET 3 0F 3 FIG. 6

INVENTOR. ROBERT 7'- MA/TLAND AT ORNEY ELECTRONICS CAIRD EXTRACTOR CROSS-REFERENCE TO RELATED APPLICATION The present invention relates to an electronics card extractor which relates to an extractor for effecting an extraction of a printed circuit card having a card electrical connector normally engaged in an electrical connector in the box which may be of a type disclosed and claimed in a U.S. Pat. No. 3,404,362 granted Oct. 1, I968 to Dino Amendola for Selective Indexing Guide Device For Electrical Connectors of Printed Circuit Cards and which patent has been assigned to The Bendix Corporation.

BACKGROUND OF THE INVENTION l. Field of the Invention Thepresent invention relates to a means for sequentially effecting an extraction of a circuit card connector from engaging relation with a box connector and thereafter a withdrawal of the circuit card from within a box holder.

2. Description of the Prior Art In recent years, printed circuitry has been used extensively in electrical equipment applied to automatic pilots, computers and amplifiers, and to a large number of removable subassemblies for use in such electrical equipment. These subassemblies are connected electrically by means of electrical connectors of the plug-in type such as disclosed and claimed in the forenoted U.S. Pat. No. 3,404,362.

Such printed circuitry is frequently in the form of a printed circuit board or pointto-point wiring board commonly called a card. The cards are assembled into a card holder box containing connectors and cabling to interconnect the cards. Slides or guides are usually attached to, or part of, the walls of the holder box.

SUMMARY OF THE INVENTION A feature of the subject electronics card extractor includes the provision of a pair of extractors pivotally'mounted at op-. posite outer comers of a circuit card so as to be readily operative by a handle extending between the extractors, the extractors having retaining pins projecting from operative arm portions of the extractors and slidably mounted in longitudinal slots provided in end portions of the handle, the longitudinal slots provided in the end portions of the handle being so arranged as to be effective upon the handle being raised by the operator to cause the extractors to be pivoted so as to cause projecting end portions of both extractors to simultaneously bear upon opposite upper edge portions of a card holder to initially provide an extraction force to effect a full disengagement of the card from a connector mounted on the lower surface of the box, and thereafter upon completion of the extraction of the card connector from the box connector the extractor retaining pins reach an extreme limit of slidable travel in the longitudinal slots in the end portions of the handle so that upon the operator continuing to raise the handle the extractors then function to withdraw the card from the card holder, the extracting and card withdrawing forces being applied in sequence in one smooth upward motion.

An object of the present invention is to provide a device in which due to the mechanical arrangement of the electronics card extractor embodying the present invention it is possible to move the card with much less force than normally required.

Another object of the invention is to provide an electronics circuit card extractor in which extraction and withdrawal forces may be exerted by the operator through a handle and not against the delicate electronic parts which take up all available grasping space on the circuit card.

Another object of the invention is to provide an electronics card extractor in which the extracting and card withdrawing forces are applied in sequence in one smooth upward motion by the operator through the extraction handle.

Another object of the invention is to provide such a card extractor device in which the use of a handle equalizes the withdrawal forces and prevents the cards from cocking and thereby binding in the slides, or from bending the pins of the connectors and which also allows a singlehanded withdrawal by the operator while leaving the other hand of the operator free to restrain and steady the card holding box.

Another object of the invention is to provide a card extractor device in whichinsertion of the circuitry card in a box holder is made easier because of a smooth flat surface of a handle which offers an ideal platform against which to apply the fingertips of the operator when pressing the card into full connector engagement.

A further object of the invention is to provide an electronics card extractor including a stiffener structure to support a top edge of the circuit card so as to dampen vibrations and support the card when in an operative position.

A still further object of the invention is to provide a box cover with a resilient pressure pad which serves to press down on the handles of several electronics card extractors to ensure full connector mating between the respective card connectors and the counterpart box connectors and ensure against disconnection thereof by vibratory effects during flight of the aircraft carrying the card holder box so that the handle assembly because of its location can contribute greatly to card and connector reliability.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings in which corresponding numerals indicates corresponding parts throughout the several drawings:

FIG. I is a side sectional view of the printed circuit card holder box with the card positioned in the box with the electrical connectors mated.

FIG. 2 is an enlarged fragmentary sectional view of the extractor and extractor retaining pin of FIG. 1 taken along the lines 2-2 and looking in the direction of the arrows.

FIG. 3 is an enlarged fragmentary sectional view of the extractor handle and stiffener structure taken along the lines 3-3 of FIG. I and looking in the direction of the arrows.

FIG. 4 is a side sectional view of the printed circuit card holder box with the printed circuit card in a raised position showing the connectors in a disengaged position.

FIG. 5 is a diagrammatic illustration of the extractor of the present invention in which there has been illustrated a force available for extraction of approximately five times the input force due to the mechanical arrangement of the operating parts.

FIG. 6 is a fragmentary perspective view illustrating the extractors of the present invention as applied to card holder box and showing a cover in a raised position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 4 there is indicated by the numeral 12 an electronics circuit card of conventional-type installed in a card holder box I4. The circuit card 12 is held in an upright position by tracks or

slides

16 and 18 secured at opposite sides of the box assembly and opening toward each other to slidably receive corresponding side edges of the circuit card 12., An electrical connector 20 of conventional type is secured at the lower edge of the card 12 by

suitable bolts

21 and 22. The connector 20, as explained in the aforenoted U.S. Pat. No. 3,404,362, includes suitable prongs for mating with corresponding prongs carried by its counter part connector 25 mounted on a bottom plate 27 of the holder 14 and from which the connector 25 may be disengaged by raising the card 12 and thereby the connector 25 from an engaging relation as shown by FIG. 4. The box connector 25 is secured in the bottom plate 27 of the box 14 by

suitable fasting bolts

29 and 30.

The mechanism for extracting the card 12 and connector 20 from engaging relation in the box connector 25 includes an extractor handle 35 formed of a U-shaped metal beam of a length variable in relation to the width of the card 12 to which it is assembled. A stiffener structure 37 includes a member formed of a suitable hard self-lubricating plastic such as delrin made to conform to the inside of the center section of the handle. 35 which is held in position by a notch 39 formed in opposite side flange portions d of the stiffener handle 37 and arranged to be engaged by prongs formed in the metal handle 35 and indicated by the numerals .43 and 45 of FIG. 3. The flange portions 40 of the stiffener 37 define there between a longitudinal channel as in which is slidably positioned an upper edge of the circuit card I2 in an arrangement, such as 7 shown in FIG. ll, so as to provide rigidity to the upper span of ing longitudinally extending

arms

54 and 56 projecting from opposite sides of the lever pivot 52, as best shown in FIGS. I and d. The arm 5 is formed of a greater length than the arm 56 and the length of the respective arms have approximately a 4:1 ratio.

An extractor retaining pin 55 is mounted in the arm 54 adjacent to the free end thereof and serves to link the extractor 50 to the handle 35. As best shown in FIG. 2 the extractor retaining pin 55 has a ltnurled center portion on which provides an interference fit with the arm 54 of the plastic extractor. 50, while circular end pieces 62 of the extractor retaining pin 58 slide in suitable slots 6% formed in opposite end portions of the handle 35 to provide linkage means, including lost motion connecting means as shown in FIGS. I and I.

This linkage means including the lost motion connecting means is effective upon the operator initially moving the handle 35 outwardly relative to the open end of the box I 3 to pivot the extractors 50 in a first sense relative to the circuit card 12 upon the handle 35 being positioned over a first predetermined operating range. Such operation of the handle 35 in turn serves to actuate the circuit card I2 so as to disengage the connector 20 carried by the circuit card I2 from operative engagement by the electrical connector 25 at the bottom plate 27 of box Id, as hereinafter explained with reference to the Extractor Operation.

Furthermore at the limit of operation of the lost motion connecting means, defined by the slidable movement of the pins 58 in the longitudinal slots ti -l formed in the end portions of the handle35, the pins 50 at the limit of the longitudinal slots 6 engage surfaces. defining inner ends of the slots 64 so as to directly couple the respective end portions of the handle 35 through the arms 5 of the extractors 50 and the fasteners 52 to the circuit card 112, as shown by FIG. I. Thereafter, the handle 35, as thereby directly coupled to the circuit card I2, may be effectively positioned by the operator over a second predetermined operating range to cause the withdrawal of the circuit card I2 from the holder M, as hereinafter explained.

Moreover, as shown in FIG. 2, the arm 5 8 of the extractor 50 has a longitudinal slot formed therein for receiving upper end edge portions of the circuit card I2. Further, as best shown in FIG. 3, the circuit card I2 has provided in the upper edge thereof the notches as for receiving the extractor retaining pins 58 upon the extractor handle 35 and the extractors 50 being positioned, as shown by FIG. I, with the circuit card I2 positioned in the box Id with the

connectors

20 and 25 in mating relation.

Further, as shown in FIGS. I and It, the card box holder I4 includes a box cover '75 having suitable fastening screws 78 for securing the cover '75 on the top of the card box holder M. Further extending longitudinally along the under side of the cover 75 and intermediate the opposite sides of the cover 75 is a suitable resilient plastic strip or rubber hold down element 80. Upon the box cover 75 being fastened in position the hold down element 1% provides a resilient pressure pad which acts a to press down on the handles 35, as best shown in FIG. I, to

ensure full connector mating between the

electrical connectors

20 and 25 during flight of an aircraft carrying the assembly I4. It can be seen from FIG. I and FIG. 6 that the handle assembly 35 because of its location will beheld by the resilient pressure pad so as to contribute to card and connector reliability.

EXTRACTOR OPERATION Referring now to the FIGS. ll, 4 and 6 operation of the electronics card extractor of the presentinvention may be readily seen. Thus FIG. I shows a circuitry card, 12 installed in a typical electronics box I4 with the cover 75 in-an assembled position. The card I2 is held in an upright position by the card slides I6 and 18 secured to opposite side surfaces of the box assembly M.

As shown in FIG. I, the card connector 20 is firmly mated in its counterpart box connector 25 with the handle 35 and extractors 50 shown with the

arms

54 and 56 in a horizontal position resting on a top edge of the circuitry card I2. The outer extreme ends of both extractors, that is the arm portions 56 are located above the reinforced edge I9 of the sides of the box I4.

This reinforced box edge 119 as shown in FIGS. 1, 4 and ti has been reinforced with a narrow strip of material which stiffens the box edge and also provides a platform for the extractor arms 56 to operate against. This platform 19 may for example have a minimum width of 0.100 inch. The design of both the box and the card assemblies is such that there will always be a clearance between the extractor arm 56 and the box edge I9 in the forenoted mating position of FIG. I.

The foregoing clearance between the extractor arm 56 and the box edge I9, as shown in FIG. I, is to assure full mating between the

connectors

20 and 25. It also permits the handle 35 to be lifted to a point of easy grasp prior to the operator picking up the load to effect disengagement between the

connectors

20 and 25.

Thus in order to extract the card I2 from the box I4, as shown for example by FIGS. I, I and 6, it is necessary for the operator to grasp the handle 35 in the center between the tip of the thumb and forefinger and pull upward. As the handle 35 is raised by the operator, the retainer pins 58 are slidably positioned in the longitudinal slots 64 formed in opposite end portions of the handle 35 to provide the lost motion connecting means which while transmitting no motion directly to the card I2 during the first predetermined limited range of operation of the handle 35 will transmit an upward force to the inner arms 54 of the extractors 50. The extractors 50 then will pivot on the eyelets 52 at the corners of the card I2 and this will in turn force downwardly the outer relatively shorter arms 56 of the extractors 50 and position them on the reinforced edge platform I9 of the box M which in effect becomes a fulcrum, as illustrated diagrammatically in FIG. 5.

It follows then that for a given force applied to the handle 35 we have approximately five times the input force available for extraction of the connector 20 from the connector 25, as shown by way of example by the diagrammatic illustration of FIG. 5. The results, shown on the diagram of FIG. 5, have been given by way of example for the particular size configuration set forth thereon.

Moreover, due to the size relationship between the extractors 50 and the length of the slots 64 in the handle 35, the extractors function through an angle of about 65 during this first predetermined range of operation of the handle 35. This translates to an extraction of the connector 20 from the box connector 25 of more than enough to effect full disengagement. From this point upward then, as shown in FIG. 45, the handle 35 is directly coupled through the inner end surfaces of the slots 6% engaging the pins 58 of the arms 54 of the extractors 50 and the fasteners 52 to the circuit card I2 so that the handle 35 effectively function over a second predetermined operating range as a convenient withdrawal device for the circuit card 12.

Particular attention is drawn to the unique function of the stiffener structure 37 which provides a structure to support the topedge of the circuitry card 12 which edge would otherwise be unsupported. If the card 12 is very wide and loaded with heavy components, this upper edge is subject to flexing during high-vibration input. When the card 12 is in an operating position, as shown in FIG. 1, the stiffener structure 37 straddles the top edge of the circuitry card 12 as shown in FIG. 3. When the card 12 is in an operating position, the stiffener structure 37 supported by the handle 35 serves to dampen the vibrations and support the card 12 in this area.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear obvious to those skilled in the art may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definition of the limits of the invention.

lclaim:

1. In a box for removably mounting circuit cards, the box being of a type having an open end and a wall at an opposite end of the box, longitudinally extending tracks carried by inner surfaces of opposite sidewalls of the box, the tracks extending in substantially parallel relation to receive a circuit card inserted through the open end of the box, the tracks being spaced apart a distance corresponding to a preselected dimension of the circuit card with the tracks opening toward each other to slidably receive corresponding side edges of the circuit card, a first electrical connector mounted on the circuit card adjacent a lower edge of the circuit card, and a second electrical connector mounted on the wall at said opposite end of the box for operative engagement by the first electrical connector; the improvement comprising extractors pivotally mounted at opposite corners of the circuit card and adjacent an upper edge of the circuit card, an operator-operative handle, means pivotally connecting the handle between the extractors, and the connecting means being effective upon the operator moving the handle outwardly relative to the open end of the box to effect a pivotal movement of the extractors relative to the circuit card in a sense to cause portions of the extractors to bear upon edges of the sidewalls of the box adjacent the open end of the box to in turn force the circuit card outward relative to the open end of the box so as to disengage the first electrical connector carried by the circuit card from operative engagement by the second electrical connector mounted on the wall at said opposite end of the box, and thereafter the handle being operable by the operator for slidably withdrawing the circuit card out the open end of the box, a stiffener element carried by the handle, the stiffener element having a longitudinal channel provided therein for receiving an upper edge of the circuit card upon the handle being forced inwardly relative to the box so that the stiffener element may act to support the upper edge of the circuit card from bending under vibratory forces.

2. The improvement defined by claim 1 in which the operator-operative handle includes arm portions projecting from opposite sides'of the handle, each arm portion of the handle having a longitudinal slot therein; the means pivotally connecting the handle between the extractors including a retainer pin projecting from an arm portion of each extractor and slidably positioned in the longitudinal slot in the correspond ing arm portion of the handle so as to cause upon the operator moving the handle outwardly relative to the open end of the box a simultaneous pivotal movement of both extractors relative to the circuit card in a sense to cause another arm portion of each extractor to bear upon edges of the sidewalls of the box adjacent the open end of the box to effect the disengagement of the first electrical connector from the second electrical connector.

3. In a box for removably mounting circuit cards, the box being of a type having an open end and a wall at an opposite end of the box, longitudinally extending tracks carried by inner surfaces of opposite sidewalls of the box, the tracks extending in substantially parallel relation to receive a circuit card inserted through the open end of the box, the tracks being spaced apart a distance corresponding to a preselected dimension of the circuit card with the tracks opening toward each other to slidably receive corresponding side edges of the circuit card, a first electrical connector mounted on the circuit card adjacent a lower edge of the circuit card, and a second electrical connector mounted on the wall at said opposite end of the box for operative engagement by the first electrical connector; the improvement comprising extractors pivotally mounted at opposite corners of the circuit card and adjacent an upper edge of the circuit card, an operator-operative handle, means pivotally connecting the handle between the extractors, and the connecting means being effective upon the operator moving the handle outwardly relative to the open end of the box to effect a pivotal movement of the extractors relative to the circuitcard in a sense to cause portions of the extractors to bear upon edges of the sidewalls of the box adjacent the open end of the box to in turn force the circuit card outward relative to the open end of thebox so as to disengage the first electrical connector carried by the circuit card from operative engagement by the second electrical connector mounted on the wall at said opposite end of the box, and thereafter the handle being operable by the operator for slidably withdrawing the circuit card out the open end of the box, a cover for the box, means for securing the cover adjacent the open end of the box, a resilient pressure pad positioned between the cover and the operator-operative handle to hold the handle in a full connector engaging position, a stiffener element carried by the handle, the stiffener element having a longitudinal channel provided therein for receiving an upper edge of the circuit card upon the handle being forced inwardly relative to the box so that the stiffener element may act to support the upper edge of the circuit card from bending under vibratory forces.

4. In a box for removably mounting circuit cards, the box being of a type having an open end and a wall at an opposite end of the box, longitudinally extending tracks carried by inner surfaces of opposite sidewalls of the box, the tracks extending in substantially parallel relation to receive a circuit card inserted through the open end of the box, the tracks being spaced apart a distance corresponding to a preselected dimension of the circuit card with the tracks opening toward each other to slidably receive corresponding side edges of the circuit card, a first electrical connector mounted on the circuit card adjacent a lower edge of the circuit card, and a second electrical connector mounted on the wall at said opposite end of the box for operative engagement by the first electrical connector; the improvement comprising extractors pivotally mounted at opposite corners of the circuit card and adjacent an upper edge of the circuit card, an operator-operative handle, linkage means pivotally connecting the handle between the extractors, and the linkage means including lost motion connecting means effective upon the operator initially moving the handle outwardly relative to the open end of the box over a first predetermined operating range to effect a pivotal movement of the extractors relative to the circuit card in a first sense to cause portions of the extractors to bear upon edges of the sidewalls of the box adjacent the open end of the box to in turn force the circuit card outward relative to the open end of the box so as to disengage the first electrical connector carried by the circuit card from operative engagement by the second electrical connector mounted on the wall at said opposite end of the box, the lost motion connecting means including means limiting the pivotal movement of the extractors in said first sense upon the first electrical connector being forced fully out of operative engagement with the second electrical connector, and the linkage means being thereafter effective upon the handle being further operable by the operator over a second predetermined operating range to couple the handle to the card in a second sense for slidably withdrawing the circuit card out the open end of the box, the operator-operative handle including arm portions projecting from opposite sides of the handle, thelinkage means including each arm portion of the handle having .a longitudinal -slot therein; the means pivotally connecting the handle between the extractors including a retainer pin projecting from anarm portion of each extractor and slidably positioned in the longitudinal slot in the corresponding arm portion of the handle so as to cause upon second electrical connector, a stiffener element carried by the handle, the stiffener element having a longitudinal channel provided therein for receiving'an upper edge of the circuit card upon the handle being forced inwardly relative to the box so that the stiffener element may act to support the upper edge of the circuit card from bending under vibratory forces, a cover for the box, means for securing the cover adjacent the open end of the box, a resilient pressure pad positioned betweenthe cover and the operator-operative handle to hold the handle in a full connector engaging position.

Claims

2. The improvement defined by claim 1 in which the operator-operative handle includes arm portions projecting from opposite sides of the handle, each arm portion of the handle having a longitudinal slot therein; the means pivotally connecting the handle between the extractors including a retainer pin projecting from an arm portion of each extractor and slidably positioned in the longitudinal slot in the corresponding arm portion of the handle so as to cause upon the operator moving the handle outwardly relative to the open end of the box a simultaneous pivotal movement of both extractors relative to the circuit card in a sense to cause another arm portion of each extractor to bear upon edges of the sidewalls of the box adjacent the open end of the box to effect the disengagement of the first electrical connector from the second electrical connector.

3. In a box for removably mounting circuit cards, the box being of a type having an open end and a wall at an opposite end of the box, longitudinally extending tracks carried by inner surfaces of opposite sidewalls of the box, the tracks extending in substantially parallel relation to receive a circuit card inserted through the open end of the box, the tracks being spaced apart a distance corresponding to a preselected dimension of the circuit card with the tracks opening toward each other to slidably receive corresponding side edges of the circuit card, a first electrical connector mounted on the circuit card adjacent a lower edge of the circuit card, and a second electrical connector mounted on the wall at said opposite end of the box for operative engagement by the first electrical connector; the improvement comprising extractors pivotally mounted at opposite corners of the circuit card and adjacent an upper edge of the circuit card, an operator-operative handle, means pivotally connecting the handle between the extractors, and the connecting means being effective upon the operator moving the handle outwardly relative to the open end of the box to effect a pivotal movement of the extractors relative to the circuit card in a sense to cause portions of the extractors to bear upon edges of the sidewalls of the box adjacent the open end of the box to in turn force the circuit card outward relative to the open end of the box so as to disengage the first electrical connector carried by the circuit card from operative engagement by the second electrical connector mounted on the wall at said opposite end of the box, and thereafter the handle being operable by the operator for slidably withdrawing the circuit card out the open end of the box, a cover for the box, means for securing the cover adjacent the open end of the box, a resilient pressure pad positioned between the cover and the operator-operative Handle to hold the handle in a full connector engaging position, a stiffener element carried by the handle, the stiffener element having a longitudinal channel provided therein for receiving an upper edge of the circuit card upon the handle being forced inwardly relative to the box so that the stiffener element may act to support the upper edge of the circuit card from bending under vibratory forces.

4. In a box for removably mounting circuit cards, the box being of a type having an open end and a wall at an opposite end of the box, longitudinally extending tracks carried by inner surfaces of opposite sidewalls of the box, the tracks extending in substantially parallel relation to receive a circuit card inserted through the open end of the box, the tracks being spaced apart a distance corresponding to a preselected dimension of the circuit card with the tracks opening toward each other to slidably receive corresponding side edges of the circuit card, a first electrical connector mounted on the circuit card adjacent a lower edge of the circuit card, and a second electrical connector mounted on the wall at said opposite end of the box for operative engagement by the first electrical connector; the improvement comprising extractors pivotally mounted at opposite corners of the circuit card and adjacent an upper edge of the circuit card, an operator-operative handle, linkage means pivotally connecting the handle between the extractors, and the linkage means including lost motion connecting means effective upon the operator initially moving the handle outwardly relative to the open end of the box over a first predetermined operating range to effect a pivotal movement of the extractors relative to the circuit card in a first sense to cause portions of the extractors to bear upon edges of the sidewalls of the box adjacent the open end of the box to in turn force the circuit card outward relative to the open end of the box so as to disengage the first electrical connector carried by the circuit card from operative engagement by the second electrical connector mounted on the wall at said opposite end of the box, the lost motion connecting means including means limiting the pivotal movement of the extractors in said first sense upon the first electrical connector being forced fully out of operative engagement with the second electrical connector, and the linkage means being thereafter effective upon the handle being further operable by the operator over a second predetermined operating range to couple the handle to the card in a second sense for slidably withdrawing the circuit card out the open end of the box, the operator-operative handle including arm portions projecting from opposite sides of the handle, the linkage means including each arm portion of the handle having a longitudinal slot therein; the means pivotally connecting the handle between the extractors including a retainer pin projecting from an arm portion of each extractor and slidably positioned in the longitudinal slot in the corresponding arm portion of the handle so as to cause upon the operator moving the handle outwardly relative to the open end of the box a simultaneous pivotal movement of both extractors relative to the circuit card in a sense to cause another arm portion of each extractor to bear upon edges of the sidewalls of the box adjacent the open end of the box to effect the disengagement of the first electrical connector from the second electrical connector, a stiffener element carried by the handle, the stiffener element having a longitudinal channel provided therein for receiving an upper edge of the circuit card upon the handle being forced inwardly relative to the box so that the stiffener element may act to support the upper edge of the circuit card from bending under vibratory forces, a cover for the box, means for securing the cover adjacent the open end of the box, a resilient pressure pad positioned between the cover and the operator-operative handle to hold the handle in a full connector engaGing position.