US 2896751 A
Description (OCR text may contain errors)
July 28, 1959 B. w. HENRICHS I 2,896,751
TOGGLE BOLT LATCH Fi led Nov. 16, 1956 islllllllli INVENTOR. 852N420 w. Alene/ms By 6W ATTOZ/VEKS nited States TOGGLE BOLT LATCH Bernard W. Henrichs, Northridge, Calif., assignor to Clark Hartwell, doing business under the name oi. lalrtweli Aviation Supply Company, Los Angeles,
Application November 16, 1956, Serial No. 622,578 2 Claims. (Cl.189--35) This invention relates to toggle bolt latches, and in. cluded in the objects of this invention are:
First, to provide a toggle bolt latch which is particularly adapted for externally flush installation in a contoured structure, such as an aircraft wing, fuselage, or appendage, so that when in its closed position the latch is completely flush with the surrounding structure.
Second, to provide a toggle bolt latch which provides free movement of the latch handle between its flush position and a manually accessible position so that when desired the latch may be readily operated.
Third, to provide a latch of this type wherein loads imposed on the latching element when in its locked position are resisted by a lever and stop means and directly transmitted to the mounting. frame structure, the operating handle being so varranged as to be essentially free of such loads.
Fourth, to provide a particularly compact latch capable of securely latching component structures under conditions of excessive loads, such as are encountered by supersonic aircraft.
With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings in which:
Figure 1 is a side view of the latch in its latching position, indicating by dotted lines the free travel of the handle member and indicating fragmentarily and by broken lines the outline of the structure in which the latch is mounted;
Fig. 2 is a bottom view of the latch structure;
Figs. 3, 4 and arejtransverse sectional views through 3-3, 4-4, 55, respectively, of Fig. 1;
Fig. 6 is a side view of the latch similar to Fig. 1, but showing the latch in its open position and indicating friagmentarily and by broken lines adjacent portions of the structure in which the latch is mounted.
The toggle bolt latch includes a pair of side plates 1 which are joined by a pair of journal bushings 2 and 3 to form a frame structure. The journal bushings are tubular to receive mounting bolts 4 for attachment to the adjacent structure in any suitable manner, not indicated.
Pivotally mounted on the journal bushing 2 is a pair of toggle latch arms 5 which are separated on the bushing and held adjacent the side plates 1 by a sleeve 6. The extremities of the toggle latch arms 5 are joined by a latch pin 7.
Mounted on the journal bushing 3 is a pair of lever members 8 spaced by a sleeve 9. The lever members are pivoted intermediate their ends to form arms 10 which are joined through a journal pin 11 to one end of a link 12, the other end of which is connected by a journal pin 13 to the toggle latch arms 5. The link member 12 is located in the space between the pairs of lever members 8 and toggle latch arms 5.
The remaining arms 14 of the lever members 8 move.to and from engagement with a stop pin 15, so located that when the arms 14 engage the stop pin 2,896,751 Patented July 28, 1959 the axis of the journal pin 11 occupies a slightly off center position relative to the axis of the journal b ushing 3 and the journal pin 13. In such position, the latch pin 7 and the extremities of the toggle latch arms 5 are locked in position against any loads that may be imposed thereon.
A handle 16 is provided which may be formed of sheet metal and channel-shape in cross section, thus comprising side flanges 17 and 18 connected by a cross web 19. The side flanges 17 are journaled near one end of the handle on the journal bushing 3. Their extremities are provided with arcuate slots 20 which fit over the extremities of the journal pin 11, so that the handle 16 is capable of moving the journal pin 11 but is capable of free motion determined by the length of the slots 20.
The handle 16 extends longitudinally a substantial distance from the side plates 1, the web. 19 projecting beyond the side flanges 1'7 and 18. At this extremity the web 19 is provided with a screw aperture 21 which receives a screw or other suitable fastening device, not shown, for the purpose of securing the handle to a surrounding structure.
A spring 22 is wrapped about the sleeve 9 and bears between the handle web 19 and stop pin 15 so as to urgethe handle toward the limit of its free motion, indicated by the dotted line position thereof in Fig. 1.
()peration of the toggle bolt latch is as follows:
The latch is intended to be mounted in a contoured structure, such as an aircraft fuselage or wing, or appendage. It is essential that the web of the handle 16 be substantially flush with the surrounding structure; for that reason the side flanges 17 and 18 may not be identical butmay be varied in construction, so that the transverse surface of the web 19' may be angularly related to the remaining elements of the latch and conform to the surrounding structure, as indicated best in Figs. 3, 4, and 5. Also the handle may be longitudinally curved. The shape and form of the handle may vary considerably without affecting its operative relationship with the other elements of the latch.
The toggle latch arms 5 may also vary in length and shape so as to engage hooks, such as that designated A in Fig. 6, or other elements, companion to the latch pin 7. When the latch is in its closed or operating position, the toggle latch arms 5 are extended and the latch pin 7 is in engagement with an appropriate companion element.
The link 12 is so disposed that the journal pin 11 is slightly past center with respect to the journal bushing 3 and journal pin 13 with the arms 14 of the lever members 3 bearing against the stop pin 15. In such position it is impossible to move the toggle latch arms 5 by engagement with their extremities of any non-descructive force. Under such conditions no load is imposed on the handle 16. However, the extremity of the handle is secured by a suitable screw or other fastening device, not shown.
When it is desired to open the latch, the screw or fastening device retaining the handle 16 is disconnected, whereupon the spring 22 urges the handle to a manually accessible position, such as the dotted line position shown in Fig. 1. The handle may then be moved manually to the solid line position shown in Fig. 6. This movement causes the ends of the slot 20 to engage the journal pin 11 and move the journal pin clockwise, as shown in the drawings, from the position shown in Fig. 1 to the position shown in Fig. 6. In so doing, the link 12 pivots the toggle latch arms '5 in a clockwise direction, as viewed in the drawings, so as to disengage the latch pin 7 from its companion element. To return the latch to its locking position, the movement of the handle 16 is reversed.
It should be noted that while the latch, when in its closed position, normally imposes no load on the handle 16, should there be a counter-clockwiseload imposed on the link 12 to cause-it to pivot about its journal pin 13, such movement is resisted by the handle 16 and the fastening device which connects the handle to the surrounding structure.
While a particular embodiment of this invention has been shown and described, it is not intended to limit the same to the exact details of the construction set forth, and it embraces such changes, modifications, and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.
What is claimed is:
1. A toggle bolt latch, comprising: a mounting frame adapted for fixed installation in a surrounding structure; a handle lever having a handle end and an operating end, said handle lever disposed within said frame and fulcrumed about a first fixed axis intermediate its ends between a position flush with said structure and an angular position wherein said handle end extends from said structure and the operating end is depressed into said structure; a toggle element journaled in said frame about a second fixed axis; a lever member journaled with said handle lever about said first fixed axis and extending to said operating end thereof; a link member joining s'aid lever member and toggle element for moving said toggle element between an extended and a retracted position on movement of said lever member and link member; and a lost motion connection between said lever member and said handle lever to permit limited free movement of said said mounting frame including a pair of side plates, a pair of spaced journals extending between said side plates and defining first and second fixed axes, and a stop also extending between said plates spaced from the side of the first axis journal remote from the second fixed axis journal; a toggle latch lever pivotally mounted at one end on said second fixed axis journal and movable between a latching position, wherein the extended end of said toggle latch lever is spaced from the side of said second axis journal remote from the first axis journal and an angularly related free position; a stop lever pivotally mounted on said first axis journal having an arm engaging said stop whensaid stop lever is in a position corresponding to the latching position of said latch lever; a link pivotally joining said latch lever and stop lever, said link being connected to the end of said stop lever remote from said stop engaging arm and to said latch lever inter mediate its ends, the pivotal connection between said link and stop lever adapted to occupy a predetermined overcenter position with respect to its pivotal connection with said latch lever and said first axis journal when said latch lever is in its latching position and said stop lever arm is in engagement with said stop; and a handle lever pivotally mounted intermediate its ends on said first axis and including an arm having a lost motion slot coinciding with the connection between said link and stop lever to permit limited free movement of said handle lever.
References Cited in the file of this patent UNITED STATES PATENTS 2,610,880 Gayner et a1. Sept. 16, 1952 2,750,217 Landholt June 12, 1956 FOREIGN PATENTS 622,197 Germany Nov. 22, 1935