US 2752186 A
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Description (OCR text may contain errors)
June 1956 J. A. MORRISON SAFETY CLOSURE LATCH Filed May 17, 1954 -aj Fig. I
John A. Morrison INVENTOR.
United States Patent SAFETY CLOSURE LATCH John A. Morrison, Seattle, Wash, assignor to Boeing Airplane Company, a corporation of Delaware Application May 17, 1954, Serial No. 430,258
6 Claims. (Cl. 292-139) The present invention relates to fasteners and latches and more particularly to improvements in safety type latch fasteners for closures, cowls, access doors and the like.
This invention is directed principally to improvements in flush type safety closure latches of a relatively simple and foolproof construction which is preferably devoid of a handle element or its equivalent. It comprises principally a primary latch, which may be of the sliding bolt type and which is operated by an actuating member having an opening therethrough, which opening is filled by a safety catch release lever. This lever and the primary latch actuating member cooperate to protect the safety catch mechanism, which this lever and member cooperatively form, from unauthorized actuation or tampering. The improved arrangement is such that the safety catch lever lies in a flush relationship within the opening in the primary latch actuating member from which position the lever may be depressed by the use of a screw driver or like hand-tool to release the safety catch, and by wedging action of the screw driver within the opening in the primary latch actuating member the latter may be lifted by the screw driver as a lever to thereby withdraw the primary latch bolt. In addition to its safety features, the presently improved closure fastener latch is small and compact, and being devoid of a permanent handle or equivalent element, it is relatively small and light in weight, and is particularly suited for use as an aircraft cowl fastener or closure latch.
It is, accordingly, a primary object of the present invention to provide a closure fastener or latch which is relatively compact and foolproof in its operation. It is a further object to provide such a closure fastener or latch embodying both a primary latch at the jamb between the relatively movable members and a well-protected safety catch by which the inadvertent opening of the primary latch means may be prevented. Another object is to provide a safety type closure fastener of the flush type which is devoid of an integral or permanent handle, or its equivalent.
It is a still further objective of the present invention to provide a novel safety catch actuating arm which is pivotally mounted for movement within a relatively deep hole in the primary latch actuating member by which it may be depressed for release by a screw driver or a like hand-tool. A still further object resides in the provision of such an arrangement in which the screw driver, or other tool, serves as the lever 0r handle to rotate the primary latch actuating member for release of the primary latch means. Further objects reside in the improved overall relationship of the components making up the closure fastener as well as in the details of the respective parts.
Other objects and advantages of the present invention will occur to those skilled in the art after reading the following description, taken in conjunction with the accompanying drawings, forming a part hereof, in which:
Fig. 1 is an external view of a preferred form of the 2,752,186 Patented June 26, 1956 improved closure latch with portions partly broken away as taken along the lines 11 of Fig. 2;
Fig. 2 is a transverse sectional view of the same as taken along the lines 22 of Fig. 1;
Fig. 3 is a similar view of the same with the safety catch arm depressed into the released position of the safety catch by application of the point of a screw driver; and
Fig. 4 is a similar transverse sectional view of the same with the primary latch actuating member rotated by the screw driver as a lever into the position in which the primary latch bolt is withdrawn and the two relatively movable members are separated.
Referring now to Figs. 1 and 2, the numeral 5 represents the fixed jamb fitting to which may be attached the wall or covering 6. By way of facilitating the description and explanation of the'operation of the improved closure fastener, it has been shown and described as applied to an aircraft or other vehicle wall, although it will be understood that it has general application and is definitely not limited thereto. The numeral 6 therefore might represent the skin covering of the fixed wall portion of an aircraft in streamlined alignment with the skin covering 7 of a movable cowl or access door portion meeting the fixed portion at the jamb opening 8. The fixed jamb fitting 5 may be provided with a hole or aperture 5a to receive the sliding bolt of the primary latch means 27.
Secured to the movable wall or skin portion 7 of the closure, as by the rivets or other fasteners 9, there is attached the improved flush type safety latch 16 comprising essentially the fixed housing or casing portion 11 and a plurality of movable parts to be herein more particularly described. A first of these parts is the primary latch actuating member 12 which is pivotally mounted for limited rotation upon the fixed housing 11 by means of the pivot 13. It is provided with an outer arcuate end face 12a arranged to clear the adjacent and similarly shaped inner face He of the housing 11 and its opposite end is similarly arcuately shaped as at 12c concentrically about the axis of the pivot 13 such that the cross-section of the actuating member 12 fits flush with a minimum clearance and can be moved about the pivot 13 through the opening 7a in the outer wall sheet 7.
The outer or external face of the actuating member '12 in the closed position is flush with the outer face of the wall 7 and in a direction normal thereto it is provided with an opening or recess 15 of a square or rectangular shaped cross-section which extends through to the bottom of the member 12 and along its undersurface 12b as a longitudinal groove terminating in the shoulder or detent 14 toward the pivot 13. The actuating member 12 is provided with a positioning contact surface 16 at the bottom of its arcuate end wall 12a which is adapted to bear against the adjacent surface 11b of the housing 11 in the closed flush position of the member 12. The actuating member 12 has formed integrally therewith the arms or lugs 17 and 18 extending radially from the pivot axis 13 and operatively connected with the primary latch means by mechanism to be hereinafter more fully described.
The safety catch 19 is a substantially L-shaped lever of approximately square cross-section which terminates at one end in the end contact area 20, and which in the closed position of the latch lies flush with the outer surface of the wall and of the surface of the actuating member 12 through the opening 15 in which it projects and is disposed. The opposite end of the actuating arm 19 is pivotally mounted upon the pivot 22 on the housing 11 and an intermediate detent portion 21 is disposed such that it cooperates with the above-mentioned detent 14 of the actuating member 12. In the closed position of the latch the safety catch, comprised of the detents 14 and V 21, is engaged as shown in Fig. 2 and upward or clockwise rotation of the member 21'about its pivot 13 is prevented by the detent 21. In order to maintain the safety catch lever 19 in its engaged position with the detent 14 in which its actuating end face 20 also lies flush with the outer wall, there is provided a compressionspring 28 The latter is guided for rectilinear movement within the pair of guide lugs 11d within the housing 11, preferably parallel to the outer wall face 7, for engagement with the aperture 5a in the fixed jamb fitting 5 with which it is aligned when the outer faces of the walls 6 and 7 are substantially flush in the closed position of the door.
The improved safety closure latch operates as follows: With the closure closed and in the latched position as indicated in Fig. 2, the safety catch 1421 is initially released by inserting a screw driver end 5 against the end contact area of the lever 19 and depressing the same into the position in Fig. 3 in which the point of the screw driver enters the opening 15 in the actuating member 12. Downward or counterclockwise movement of the lever 19 about its pivot is limited by its projection through and bearing against the beveled sides of the opening 11a within the housing 11 at which position the detents 14 and 21, comprising the safety catch, are disengaged and the actuating member 12 is free to berotated upwardly in the clockwise direction about the pivot 13. This is facilitated by the use of the inserted point of the screw driver whereby a relatively high force of a Wedging nature can be applied to the actuating member 12 to release it by applying a couple to the side walls 15s of the hole 15 using the leverage of the screw driver S. The application of this leverage by the screw driver imparts clockwise rotation to the member 12 whereby the points of the detents 14 and 21 are caused to pass each other and the safety catch remains disengaged as the member 12 is rotated about its pivot 13 thereby withdrawing the bolt or pin 27 by means of the integral arms 17 and the pivotally interconnected linkage mechanism 232425-26. This results in the complete Withdrawal of the end of the bolt 27 from the opening 5a and the closure can either be pulled outwardly into its opened position, either by the further application of force by the screw driver S, or by supplemental resilient means (not shown) tending to push the closure into its opened position.
It will, accordingly, be noted that an improved closure latch has. been disclosed into which a common screw driver or similar tool can be inserted, first to release the safety catch and then to act as a lever or handle for operating the latch. A particular advantage of the disclosed latch lies in its safe operation inasmuch as many closure and cowl latches as used in aircraft and vehicles are frequently thumb traps and it should be noted that the disclosed latch does not require the direct use of the hands on the latch. Inasmuch as many latches of the present type are frequently used on each airplane, or other vehicle, a substantial weight saving results from the use of a demountable handle, in the form of the screw driver, which is usually part of the mechanics tool kit. The disclosed embodiment has been shown for illustrative purposes only and it will also be apparent that the improved latch can be changed in form materially depending upon the type of primary latch which is desired and the type or placing of the safety catch. Among the principles of the improved arrangement, however, are two of the essential features which may be incorporated, namely, that the primary latch actuating member may be provided with a deep hole to accommodate the screw driver, or other tool, and secondly that the release for the safety catch may be in the deep hole and be operable by the screw driver or other tool. In other words, the arrangement embodies the pivotally mounted interfitting latch actuator and safety catch actuator, cooperating between them to form the safety catch, separable by insertion of a screw driver point which subsequently serves to move the latch actuator while simultaneously maintaining said separation.
Other forms and modifications of the present invention, whi h will occur to those skilled in the art after reading the foregoing description, are intended to come within the'scope and spirit of the present invention, as more particularly set forth in the appended claims.
1. in latch releasing mechanism for a closure, a releasing lever pivotally mounted upon the closure having a latch actuator interfitted therewith and operative for releasing said latch actuator from said releasing lever when pressure is applied to said releasing lever, a pivotal mounting for said latch actuator carried upon the closure, detent means formed upon said latch actuator and upon said releasing lever to normally hold the same interfittedwith respect to each other, and rectilinearly movable latching means pivotally linked to said latch actuator directly operated upon by said latch actuator when released by insertion of a tool applying pressure to said releasing lever and imparting release of said detent means between said latch actuator and said lever permitting separating movement between said latch actuator and said releasing lever and imparting releasing movements of said latching means upon rotative movement of said latch actuator about said pivotal mounting.
2. In a latch arrangement for a closure for a wall having an opening therein, rectilinearly movable latching means slidably carried by the closure for engagement with an edge of said wall opening, actuator means carried by said closure operatively connected to said rectilinearly movable latching means and lever means having a contact portion extendible through an opening in said actuator means, said actuating means and said lever means each mounted upon said closure upon separate but adjacent pivots, the improvement comprising detent portions cooperatively carried by said actuator means and said lever means arranged'to form a safety catch for locking said lever means to said actuator means such that application of pressure to said lever means through the opening in said actuator means causes release of said safety catch for the initial release of said actuator means from said lever means and subsequent rotation of said actuator means causes rectilinear movement of said latching means for its disengagement from the edge of said' wall opening.
3. A latch mechanism for a closure comprising a housing having a guide aperture therein, a latch bolt arranged for rectilinear motion within said guide aperture, a primary latch actuator pivotally mounted upon said housing, said primary latch actuator having an opening therethrough, a release lever pivotally mounted upon said housing and having a portion extending into the opening of said primary latch actuator flush with the external face thereof, linkage means. operatively connecting said primary latch actuator with said rectilinearly movable latch bolt, and detent means cooperatively carried by said primary latch actuator and said release lever forming a safety catch releasable by insertion of a pointed tool into the opening of said primary latch actuator for depressing said release lever and disengaging said detent means forming said safety catch thereby releasing said primary latch actuator from said release lever to facilitate rotation of said primary latch actuator about said pivotal mounting by engagement of the tool with the side walls of the opening in said primary latch actuator and utilizing the leverage of the inserted tool by applying a wedgiug pressure 7 to rotate said primary latch actuator and apply rectilinear motion to said latch bolt through the medium of said linkage means for the disengagement of the closure.
4. In a latch arrangement for a closure for a wall havin an opening therein, latching means siidably carried by the closure for engagement with an edge of said Wall opening, actuator means pivotally mounted directly upon said closure and operatively connected to said latching means, lever means pivotally mounted directly upon said closure and having a contact portion normally extendible to a position adjacent to said actuator means, said actua tor means and said lever means each mounted upon said closure upon separate but adjacent pivots, said actuator means and said lever means having complementary interfitting detent portions cooperatively carried by each said means for locking said lever means to said actuator means, and resilient means urging the said lever means against said actuator means for engagement of said detent portions arranged in such manner that depression of the core tact portion of said lever means against the opposition of said resilient means initiates release of said detent portions whereby rotation of said actuator means causes movement of said latch means for its disengagement from the edge of said wall opening.
5. A latch mechanism for a closure having a guide aperture therein, a latch bolt arranged for movement within said guide aperture, a primary latch actuator pivotally mounted upon said closure, a release element pivotally mounted upon said closure and having a contact portion normally disposed flush with an exterior surface of said primary latch actuator, said primary latch actuator and said release element each pivotally mounted upon said closure upon separate but adjacent axes Whereby both said primary latch actuator and said release element have separate but adjacent arcuate paths of movement, linkage means operatively connecting said primary latch actuator with said movable latch bolt, and detent means comprising complementary interfitting portions cooperatively carried by said primary latch actuator and said release element, said detent means releasable by applying an inwardly directed force to the contact portion of said release element for depressing said release element and its disengagement from said detent means initiating release of said primary latch actuator from said release element to permit rotation of said primary latch actuator about its pivotal mounting to move said latch bolt through the medium of said linkage means for the disengagement of the closure.
6. A latch mechanism of the type called for by claim 5 characterized by the arrangement of the primary latch actuator being contiguous to an adjacent stop portion carried by the closure to limit inward movement of said primary latch actuator about its pivotal mounting as inwardly directed forces are applied to said release element to thereby facilitate the separation of said detent portions and the release of said latch mechanism.
References Cited in the file of this patent UNITED STATES PATENTS 2,284,409 Erath May 26, 1942 2,424,962 Best Aug. 5, 1947 2,608,085 Castle Aug. 26, 1952 2,721,750 Rudis et al. Oct. 25, 1955 FOREIGN PATENTS 693,155 France Aug. 18, 1930