Toggle-action fastener

Abstract

An overcenter fastener including a relatively movable catch and latch which, when in fastened engagement become releasably locked together in such a manner that, to release them, compound movement is required--first in one relative direction, and then in another.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates generally to releasable latch fasteners, and more particularly to overcenter-type draw fasteners. Still more particularly, the invention relates to an improved overcenter-type fastener which self-locks in the latched position to prevent accidental or unauthorized opening. Overcenter-type draw fasteners are well known and widely used for releasably securing pairs of relatively movable structures together. Such fasteners are commonly used, for example, for securing truck hoods, equipment access panels or doors, machine shrouds, hatch covers and the like.

A conventional overcenter fastener comprises a pair of cooperating elements, a catch carried by one of the structures which is to be latched together, and a latch mounted on the other structure for movement toward and away from the catch, and into and out of fastened engagement with the catch. More specifically, and still considering a typical overcenter fastener, in a fastening operation the latch is first engaged with the catch through mutually contacting portions therein which permit swinging of the latch about a pivot axis to an overcenter position, drawing and securing together the structures. Normally, a spring or other biasing means acts on the latch so as yieldably to resist its movement through the overcenter position, and to hold the latch and catch together. To open the fastener the latch is swung back through its overcenter position whereupon the latch and catch disengage and free the structures.

One of the disadvantages of such a fastener is that, while it is quite a convenient type device to use in many fastening operations, it is not practical for use where security is a consideration. Since the operating motion sequence of a conventional overcenter fastener is well known, it is an easy matter for an unauthorized person to release the fastener.

A general object of the present invention is to provide a novel overcenter-type fastener which overcomes these and other drawbacks of prior art designs in a practical and satisfactory manner. A more specific object is to provide an overcenter-type fastener having parts such as those described above which characterize conventional fasteners, but in addition, including unique self-concealing locking means which releasably lock a latch and catch in fastened engagement.

A related object is to provide such a fastener wherein release of a latch and catch from a locked-together condition requires no special external device, such as a key or other tool or the like.

Still another object of the invention is to provide a fastener of the type generally outlined wherein unlocking of a latch and catch requires special compound relative movement there-between.

Still a further object of the invention is to provide a fastener as indicated which is relatively simple in construction, and which is easy to operate once one has knowledge of the relative movement required to effect release from the locked condition.

According to a preferred embodiment of the invention, the latch and catch in the fastener are each provided with a locking means--which locking means become releasably locked together as the latch and catch are moved relatively toward one another into fastened engagement. In the particular embodiment of the invention disclosed herein, the locking means in the latch comprises an opening formed therein, and the locking means in the catch comprises a finger which is adapted to become caught in this opening. The finger and opening are so arranged that when they become interlocked with the latch and catch in fastened engagement, their release may be effected only through producing, first, relative movement between the latch and catch in a plane disposed at a right angle to that plane in which the latch and catch move relatively during movement into and out of fastened engagement.

A further important feature of the fastener of the invention is that with the latch and catch locked together, the locking means therein are substantially concealed from view so that one not knowing the motion sequence for effecting release cannot, through inspection, readily determine the sequence.

These and other objects and advantages attained by the invention will become more fully apparent as the description which follows is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation showing a fastener as contemplated herein mounted on a truck and shown in a condition with a latch and catch in the fastener in locked and fastened engagement with one another;

FIG. 2 is a side elevation taken generally from the left side of FIG. 1;

FIG. 3 is a cross section taken generally along the line 3--3 in FIG. 1; and

FIGS. 4, 5 and 6 are simplified, reduced-scale side elevations illustrating a typical fastening operation.

DESCRIPTION OF PREFERRED EMBODIMENT

Turning now to the drawings and referring first to FIGS. 1-3, indicated generally at 10 is a fastener constructed in accordance with the present invention, mounted for use in conjunction with the hood 12 and body panel 14 of a truck (not shown). It should be understood that several fasteners such as fastener 10 may be used in the truck mentioned to fasten the hood in place. However, obviously only one of these fasteners need be described herein.

In general terms, fastener 10 includes a catch 16, and a latch 18 which is adapted, as will be explained, to cooperate with this catch. Attached to the latch is an elongate elastomeric link 20 which interconnects the latch and an anchor shown at 22. As will become apparent, link 20 and anchor 22 together serve as a mounting for the latch permitting movement thereof relative to the catch into and out of fastened engagement with the catch.

As can be seen especially in FIG. 1, catch 16 as viewed therein has a generally U-shaped outline. The catch includes a substantially flat mounting portion 16a which is fastened as by screws 24 to body panel 14. Joined integrally with mounting portion 16a are two projections 16b, 16c which extend upwardly from the mounting portion in FIG. 1, and which have the curving side outlines shown in FIG. 2. The curved outer ends of these projections define a pair of transversely aligned sockets 16d (see FIG. 2) which face downwardly in FIGS. 1 and 2.

Also included in the catch, and joined integrally with the mounting portion therein, is a curved finger 16e which is positioned generally on the same side of the catch as projection 16c and which comprises a locking means in the catch. This finger, as can be seen especially in FIGS. 2 and 3, curls upwardly away from body panel 14, with the outer extremity of the finger pointing to the left in FIGS. 2 and 3.

Latch 18, as viewed in FIG. 1, also has a substantially U-shaped outline. The latch may be thought of as including a central portion 18a from which extend integrally joined substantially parallel elongated arms 18b, 18c. The side outline of the latch is shown clearly in FIG. 2, and the cross-sectional configurations of the arms are shown in FIG. 3. More particularly, and with respect to the cross-sectional configurations of the arms, except with respect to a midregion along the length of arm 18c, the cross sections of the arms are substantially uniform along their lengths, and are as shown for arm 18b in FIG. 3--except of course that the cross-section of arm 18c is the mirror image of that of arm 18b. As was just mentioned, the midregion of arm 18c differs in cross sectional configuration, and in particular, is formed with what might be thought of as a bulge 18d which projects or bulges toward leg 18b. This bulge is especially apparent in FIGS. 1 and 3. Formed in bulge 18d according to the invention is a substantially rectangular opening 18e which comprises a locking means in the latch. As will be explained, opening 18e is adapted to catch the outer end of finger 16e to effect releasable locking of the latch and catch.

Completing a description of the latch, as can be seen in FIG. 1, the upper ends therein of arms 18b, 18c are bifurcated, with axially aligned latch pins 26 mounted and exposed in these bifurcations. Pins 26 are axially aligned along an axis which lies within the plane of FIG. 1 and is substantially normal to the plane of FIG. 2. As will become apparent, pins 26 are adapted to seat within (and are shown so seated) the sockets 16d previously mentioned which are formed in projections 16b, 16c in the catch.

Anchor 22 has the configuration shown in FIGS. 1 and 2, and is fastened by means of bolts 28 to hood 12 substantially directly above catch 16 in FIGS. 1 and 2. Extending between anchor 22 and latch 18, as has previously been mentioned, is link 20. As is most apparent in FIGS. 1 and 2, link 20 has a somewhat dogbone-shaped configuration and is pivoted at its upper and lower ends to the anchor and latch, respectively. More particularly, an elongated pin 30 pivots the upper end of the link to the anchor and an elongated pin 32 pivots the lower end of the link to the central portion of the latch. With the parts in the fastener in the relative positions shown in FIGS. 1 and 2, pins 30, 32 substantially parallel one another with their axes substantially paralleling the common axis of previously mentioned pins 26. Thus arranged, link 20 tends to maintain anchor 22 and latch 18 in the vertical alignment shown in FIG. 1.

While different elastomeric materials may be used in the link, a material which has been found to be especially suitable is a synthetic rubber such as Buna S or EPR, having a Durometer (A) of about 60. Catch 16 herein is formed from sheet steel of appropriate thickness. Latch 18 and anchor 22 suitably comprise aluminum or zinc castings, or, for lighter weight, molded polycarbonate plastic. Pins 26, 30 and 32 are conventional steel cylindrical split pins.

Considering how fastener 10 operates, and assuming that the latch and catch are initially disengaged, with hood 12 positioned over body panel 14 as shown in FIG. 4, latch 18 is swung to a position such as that shown with pins 26 disposed below sockets 16d. The latch is then positioned to seat the pins in their respective sockets, which seating permits downward swinging or pivotal movement of the latch with respect to the catch to draw the hood and body panel toward one another. Such action is illustrated generally in FIG. 5. During such swinging of the latch some tensing occurs in link 20, with resultant elastic elongation of the link.

With continued downward swinging or pivoting, the latch moves through an overcenter position toward a final position shown in FIGS. 1, 2 and 6, in which the latch and catch may be thought of as being in fastened engagement. Further, with pivoting of the latch toward its final position, the right hand wall of bulge 18d in FIG. 3 engages the outer extremity of finger 16e and cams the latch somewhat to the left in FIGS. 1 and 2 to a position such as that shown in dash-dot lines in FIG. 3. With continued downward pivoting of the latch, and following such camming action, the outer extremity of finger 16e enters opening 18e, as illustrated in FIGS. 1, 2 and 3. The camming action mentioned is yieldably resisted by link 20, which, with entrance of the outer end of the finger into the opening, returns the latch to the lateral position shown in solid outline in FIGS. 1 and 3. With return of the latch to that position, and with the outer end of the finger extending into the opening, the latch and catch are releasably locked in place. In other words, it is not possible to disengage these parts simply by upward swinging of the latch, such swinging being blocked by virtue of engagement between finger 16e and the wall of bulge 18d.

Especially to be noted with the parts so locked together is the fact that finger 16d and opening 18d are substantially concealed from view.

To undo the fastener, a compound relative movement is required between the latch and catch. More specifically, first, the latch must be shifted relative to the catch, i.e., to the left in FIGS. 1 and 3, to the dash-dot outline position previously mentioned. Such action shifts bulge 18d a sufficient distance to afford clearance for the outer end of finger 16e. With this accomplished, and while holding the latch in such a side-shifted position, the latch may then be swung upwardly, back through its overcenter position to disengage it from the catch.

It will thus be apparent that the fastener of the invention offers not only all operational advantages of conventional overcenter fasteners, but also an important security feature in the form of automatic locking in place of the latch and catch. Simple, but unobvious compound relative movement is required between these parts to effect release. And, through such a construction which enables release only through compound movement, the necessity for an external unlocking device such as a key, is avoided.

It will be obvious that while the parts in fastener 10 have been shown with specific configurations and cross sections, these may be modified to suit different applications. Also, the locking means used in the latch and catch may be formed or positioned differently than shown or described herein.

While a preferred embodiment of the invention has been described, and certain modifications suggested, it will be appreciated by those skilled in the art that other variations and modifications are possible without departing from the spirit of the invention.

Claims

It is claimed and desired to secure by letters patent:

1. In an overcenter-type draw fastener for releasably securing a pair of structural bodies together, comprising

a catch element mountable on one of said bodies,

an anchor mountable on the other of said bodies in opposed relation to said catch element,

a latch element engageable with said catch element and movable in a plane relative to it, and

a link operatively interconnecting said anchor and latch element and locating the latch element for pivotal movement in said plane into and out of an overcenter position for the fastener wherein said latch and catch elements are disposed in releasable, fastened interengagement,

means for releasably locking said fastener in said overcenter position, including means forming first and second lock components in said catch and latch elements, respectively, for engaging and interlocking upon said pivotal movement of the latch into said overcenter position, and, once interlocked in said position, for disengaging only upon first movement of said latch element relative to said catch element in a plane substantially different from said first-mentioned plane, movement of said latch element in said first-mentioned plane from said position being otherwise prevented.

2. The fastener of claim 1, wherein one of said lock components comprises a projection, and the other of said components comprises means defining an opening for receiving an end portion of said projection.

3. The fastener of claim 1, wherein said first lock component comprises a hook-like projection, said second lock component comprises means defining an aperture for receiving an end portion of said projection, and said latch element is configured whereby, with said fastener in said overcenter position, said projection is substantially concealed by said element.

4. The fastener of claim 1, wherein said first-mentioned plane and said different plane are substantially normal to one another.

5. The fastener of claim 1, wherein said link is a unitary body formed of an elastomeric material.

6. In a self-locking overcenter-type draw fastener for releasably securing a pair of structural bodies together, comprising

a catch mountable on a surface of one of said bodies, said catch including a socket-bearing portion extending outward from said surface,

an anchor mountable on a surface of the other of said bodies, extending outward from said surface,

a latch moveable in a plane relative to said catch, and including means therein for releasably engaging said socket,

a link interconnecting said anchor and latch, and locating the latch for pivotal movement in said plane into and out of an overcenter position for the fastener with said socket-engaging means seated in said socket,

means for releasably locking said fastener in said overcenter position, including means on said catch forming a first lock component, means on said latch forming a second lock component for engaging said first component and interlocking therewith substantially upon said latch reaching said overcenter position by said pivotal movement, and for releasing from an interlocked condition only upon movement of the latch relative to the catch in a plane substantially different from said first-mentioned plane, pivotal movement of the latch out of the over-center position through movement in the first-mentioned plane being otherwise prevented.

7. The fastener of claim 6, wherein said first-mentioned plane is substantially normal to the surface on which said catch is mounted, and said different plane is substantially parallel to said surface.

8. The fastener of claim 7, wherein said first lock component comprises a hook-like projection and said second lock component comprises means defining an opening for receiving an end portion of said projection.

9. The fastener of claim 8, wherein said latch includes a hollow, inverted-U-shaped portion having said opening in a wall section thereof, said wall section being disposed in the assembled fastener in a plane generally normal to the surface mounting said catch.

10. The fastener of claim 9, said latch being configured whereby, with said fastener in said overcenter position with said projection received within said opening, said projection is substantially concealed from view.

11. In the combination of a pair of structural bodies and a self-locking overcenter-type draw fastener for releasably securing said bodies together, said fastener comprising a first member mounted on a surface of one of said bodies and including means therein defining a catch, an anchor mounted on the other of said bodies in opposed relation to said first member, a second member moveable relative to said first member and including latch means therein for releasably engaging said catch, and an elongate link secured at its opposite ends to said anchor and second member, locating said member for pivotal movement in a plane substantially normal to said surface into and out of said overcenter position for the fastener with said latch means engaging said catch,

means in said fastener for locking the fastener in said overcenter position, including

a first lock component mounted on said surface of said one body, and

means on said second member defining a second lock component for engaging said first component and interlocking therewith upon pivotal movement of said second member in said plane into said overcenter position, and for releasing from an interlocked condition only upon movement of said second member relative to said first member in a plane substantially parallel to said surface, disengagement of said catch and latch means through relative movement of said first and second members in said normal plane being otherwise prevented.