Mechanical pressure latch

Sept. 2, 1952

R. G. NYE

MECHANICAL PRESSURE LATCH

Filed Dec. 8, 1948

2,609,268

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INVENTOR.

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ATTORNEY

Patented Sept. 2, 1952

2,609,268

UNITED STATES PATENT OFFICE

2,609,268

MECHANICAL PRESSURE LATCH Robert Glen Nye, San Diego, Calif.

Application December 8, 1948, Serial No. 64,065

Claims. (Cl. 312—320) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757)

This invention relates to operating levers designed to increase the ease with which a movable member such as a cover plate may be placed on and removed from a base member. More particularly, the invention relates to a radio chassis in the form of a drawer which is slidable on the base, there being complementary connectors at the rear of the drawer and base respectively, which frictionally engage each other. The instant invention comprehends the provision of a lever at the front of the drawer which will enhance the force needed to engage and disengage the complementary connectors as the drawer is slid into and removed from the base.

In large electronic equipment, it is customary to place the several component units on a number of different chassis which are embodied in drawers slidable on corresponding base members in the frame of the equipment. In order to obviate the requirement of lengthly flexible connectors between each chassis drawer and the frame of the equipment, it is convenient to place complementary connectors or plug members at the rear of the base and the drawer, respectively, which connectors are automatically engaged as the drawer is pushed into position on the base. Such connectors generally comprise a large number of individual plug units, and therefore require a considerable force to engage and disengage.

It is an object of this invention to provide an operating lever at the front of such a chassis drawer which will· produce multiplied force to aid in both the engagement and disengagement of the connectors at the rear of the drawer.

It is another object of this invention to provide a handle at the front of the radio chassis which will serve the double purpose, in a single movement, of forcefully disengaging the connectors at the rear of the drawer and of allowing the drawing to-be slid from the base.

It is a further object of this invention to provide a drawer with a combined actuating lever or handle and lock member, by means of which the drawer may be positively held on the base until specific manual operating steps are applied to the lever to release it, whereupon it may be used successively as a force multiplying means for disengaging the drawer from the base, and then as a handle for withdrawing the drawer from the base.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description,

The instant invention is applied to a base member to which a movable member or cover plate is selectively mounted or removed. In accordance with this invention, an operating lever ⁵ is mounted on the movable member, this lever consisting of a forked portion at one end and a handle portion at the other end, the mounting being achieved by a pivot pin pivotally mounting the lever to the movable member, and passing ¹⁰ through the lever intermediate the forked and handle portions thereof. When applied to an assembly such as a drawer slidable on a base member, the operating lever is pivoted in an aperture in the front panel of the drawer, with the forked ¹⁵ portion extending inside the panel, and the handle portion extending outside the panel.

A cross bar is mounted to the base member paralleling the front panel and engageable by the forked portion of the operating lever as the ²⁰ drawer is slid on or off the base member. Preferably the base member is recessed at the front to form a recess adjacent the cover plate or front panel, which is spanned by the cross bar so that the forked portion of the operating lever enters ²⁵ the recess and engages the cross bar as the lever is pivoted.

Outward pivoting of the handle portion of the lever causes the forked portion to bear against the cross bar in the base member, thereby initi30 ating removal of the drawer from the base member. This is done with considerable force multiplication due to the difference in lever arms, so that the connectors which are frictionally engaged at the rear of the base member and drawer, 35 respectively, are easily disengaged. After disengagement of the connectors, further outward pivoting of the lever handle results in the engagement or abutment of a shoulder formed on the forked portion, with a stop member se40 cured to the inner face of the front panel. Further pivoting being thus prevented, the operating lever then becomes a drawer handle which may be used to slide the drawer from the base member.

In order to prevent accidental outward pivoting of the operating lever, a manually operated latch is mounted at the end of the handle portion, which engages a catch or lip formed on the cover plate, so that with the drawer once in 50 place on the base member, it cannot be then removed until the latch is actuated and the operating lever pivoted outwardly on its pivot . pin.

A specific embodiment of the invention de55 scribed generally above will now be described in

2,609,268 detail with reference to the accompanying drawings, wherein:

Fig. 1 is a perspective view illustrating the invention as applied to a radio drawer chassis; and

Fig. 2 is a sectioned elevation showing somewhat more clearly certain details of the invention.

Referring to the drawing, I i designates a base member having a rear wall 12 to which is mounted an inwardly extending, electrical connector 13. Slidable on the base member ί I is a drawer I ¢, particularly suited to contain an electronic chassis. At the rear of the drawer i 4. is another electrical connector 16, adapted to frictionally engage the connector ¢3, and thereby produce the desired continuity of electrical connections between the drawer and the base member. The drawer 14 has a front panel or cover plate 17 which, in the broadest implications of the instant invention, constitutes a movable member which may be mounted on and removed from the base member ί ί.. An operating lever i 8, consisting of a handle portion 19 and a forked portion 21, is pivotally mounted to the front panel 17 by means of a pivot pin 22. This is achieved preferably by providing an aperture 23 near the bottom of the front panel 17. and mounting a U-shaped block 24 on the inside of the panel '17, embracing the aperture. 23. The pivot pin 22 passes through the block 24 parallel to the plate and across the aperture 23, so that the forked portion 21 of the lever 18 extends inside the panel 17, while the handle portion extends outside the panel.

.Engageable by .the forked portion 21 of the lever is a cross bar 26 mounted either fixedly or reliably, as desired, on the base member 11, paralleling the panel 17. This mounting is preferably achieved by recessing the base member i ί at 27 to form a recess adjacent the aperture 23 and pivot pin 22. The cross bar 26 spans the recess 27, thereby providing operating room for the forked portion 21 as the lever 18 is pivoted. Mounting of the cross pin 2.6 is achieved by securing another U-shaped block 28 to the bottom surface of the base member 11, circumjacent tlie recess 27, the bar 26 running between the arms of the U 2.8, and thereby spanning the recess 27. The bar 26 is preferably generally circular in cross section and secured rotatably to the sides of the recess 27, although other suitable cross sections may be used as long as suitable room is left for entrance and withdrawal of the bifurcations of the forked portion 2 ί.

In order that the lever 18 may be used as a regular handle to slide the drawer 14 from the base 11 after disengagement of the forked portion 21 from the bar 26, a shoulder 29 is provided on the forked portion 21, extending inwardly of the drawer. This shoulder engages, or abuts against the upper portion of the U-block 24, as shown in dot-dash lines in Fig. 2, which thus constitutes a stop member for the shoulder 29, limiting outward pivoting of the lever 18, and permitting it to be used as a handle for withdrawal of the drawer.

In order to insure against accidental outward pivoting of the handle 18 when the drawer is in closed position, a latch 31 is pivotally, mounted on the extended end cf the handle portion 19, and a cooperating catch or lip 32 is provided by perforating the panel 17. In this way, the lever 18 may not be pivoted outward until the latch 31 is pressed downward by the thumb of the operator.

Operation

The instant invention is used in the following manner. It will be assumed that the drawer 14 is separated from the base 11. To mount it on the base 11, the lever 18 is pivoted out until engagement of shoulder 29 against stop 24. The drawer 14 is then slid in on the base 11 until the forked portion .21 is about to engage the cross bar 26. At this point, the panel .17 is still a short distance out from its seated position, and occupies the attitude shown in dot-dash lines in Fig. 2. Likewise, as shown in dot-dash lines in Fig. 2, the connector (6 is about to frictionally engage connector 13.

A this point·, the lever 18 is pivoted up, or inward, thereby hooking the inner fork or bifurcation of the portion 21 over the bar 26, and drawing the pivot pin 22 and panel 17 steadily in against the resisting friction of the plugs 13, and 16. This cam or levering action continues with the forked portion 2 i sliding down and inwardly to embrace the bar 26 until the latch 31 is snapped into position over the lip 32, at which point the drawer 14 lias been fully seated on the base member 11, and the connectors 13 and 16 are fully engaged. In this position the drawer 14 is firmly latched onto the base member 11, separation of the two being prevented by the interlocking of the forked portion 2l over the bar 26.

Removal of the drawer from the base member can therefore be effectuated only by releasing the latch 31 and pivoting the operating lever 13 downward and outward. Upon such pivoting, a converse cam or lever action to that experienced upon closing the drawer is achieved, by virtue of the action of the outer fork or bifurcation of the portion 21 pushing against the bar 26. Outward pivoting on the lever 18 thus causes the outer fork of the portion 21 to cooperate with the pin 26 to push the pivot pin 22 and panel 17 away from the base member 11 in substantially the same way as the inner fork of the portion 21 pushed the drawer inward when the drawer was being inserted into the base member. Thus the plugs 13 and 16 are disengaged against their frictional resistance by the same type of cam or lever action as-was employed to engage them.

By the time the lever 18 has been pivoted outward to the point where the shoulder 29 abuts the u-stop block 24, the inner fork of the portion 21 has been lifted clear of the bar 26, and the connectors 13 and 16 have been fully disengaged so that the drawer 14 may be easily slid outward on the base member 11, using the handle portion 19 in conventional fashion as a drawer pull.

It will be noted that as the drawer is pushed home onto the base member II, the mechanical advantage of the operating lever steadily increases. This is due to the fact that the inner fork of the portion 21. steadily slides down the pin 26, thereby, shortening the lower lever arm, represented by the distance between the bar 23 and the pivot pin 22, while the upper lever arm, represented by the; handle portion 19, remains constant. In this, way the maximum mechanical advantage, represented by the maximum mechanical lever ratio, is achieved just exactly where it is desired—namely, when the plugs 13 and IS are fully engaged, and when their frictional resistance is therefore greatest.

Likewise, upon disengagement of the plugs 13 and 16, maximum force multiplication is achieved upon the start of disengagement, because then the lever arm distance between the bar 26 and

2,609,268 the pivot pin 22 is least. As disengagement progresses, this lever arm is increased, lessening the mechanical advantage ratio, but at the same time, . increasing the travel ratio, so that greater travel of the drawer is achieved for a given arc of pivoting of the lever 18. That’is to say, the horizontal distance travelled by the drawer 14 in withdrawing from the bas J J is roughly proportional to the tangent of the pivot angle of the handle 19 as the latter is pivoted out to disengage the drawer. Thus, at the start of disengagement, the drawer travel per degree of handle pivoting is small; steadily increasing as the handle is pivoted, and reaching its maximum just prior to complete disengagement of the drawer from the base.

The instant invention thus produces maximum force multiplication where it is needed—namely, when the drawer is fully seated on the base member ί i; without sacrificing travel distance advantage at the outer portion of the span when the plugs ί 3 and ί 6 are almost disengaged and large mechanical force ratio is. not required.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.