US3468579A - Tilt plate latch release - Google Patents

Description

Sept. 23, 1969 P. c. TABOR 3,468,579

TILT PLATE LATCH RELEASE Filed Sept. 15, 1967 UNZOCKED 1 3? 5. I aiwm United States Patent 3,468,579 TILT PLATE LATCH RELEASE Paul C. Tabor, Clawson, Mich., assignor to Meteor Research Limited, Roseville, Mich., a partnership Filed Sept. 15, 1967, Ser. No. 668,048 Int. Cl. Ec 17/38, 17/02 U.S. Cl. 292-306 7 Claims ABSTRACT OF THE DISCLOSURE A latch of the tilt plate type provided with a movable abutment about which a tilt plate is caused to pivot, by a spring, to frictionally bind a latch pin extending through a hole in the plate. The abutment is rotatable to an inactive position to permit the plate to assume a non-tilted position, under the influence of the spring and other forces, and release the latch pin.

Cross reference to related application The present application discloses an improvement in the latch structure shown in my copending application Ser. No. 649,608, filed June 28, 1967. The improvement of the present application adapts the latch structure of the copending disclosure to a wider variety of uses.

Backgroundof the invention This invention relates to tilt plate latches wherein a latch pin may be projected through an opening in a plate and the plate tilted to bind and grip the latch pin to hold the latch in closed condition. The present invention relates particularly to novel means for releasing the tilt plates grip on the latch pin.

It is known in the prior art to provide latches wherein a pin is carried by a closure member, for example, and which is projectible into an opening through a tiltable plate on a frame or container member. Tilting of the plate thus effects frictional grip of the latch pin to hold the same against removal. In the prior devices, however, release of the latch pin was effective by forcibly tilting the plate in the opposite direction against the action of any spring or other forces present and in many instances this required the exertion of considerable force by a release lever.

Summary of the invention In the normal operation of tilt plate latch devices, a tiltable apertured plate normally bears against a fixed abutment serving as a fulcrum about which a spring or similar device causes the plate to pivot to thus tilt the same relative to the axis of a latch pin passing through the aperture. The force of the spring tends to hold the plate in tilted condition and any force applied to the latch pin in a direction tending to withdraw it from the tilt plate merely causes the plate to bear harder against the fixed abutment and results in additional tilting bias and a tighter grip on the pin. If such a withdrawal force is customarily present, considerable force must be exerted on the tilt plate to return it to non-tilted condition.

The present invention involves a novel abutment structure about which the tilt plate is normally tilted to grip the latch pin and which abutment is movable so as to be capable of being withdrawn from the tilt plate to an inactive position and thus permit the very forces which tend to hold the latter in tilted condition to move the same to a non-tilted position and release the latch pin. In a preferred embodiment the abutment is an eccentric portion of a rotary shaft so that mere rotation of the shaft will withdraw the abutment from its normal engagement with the tilt plate and permit the above-described release.

3,468,579 Patented Sept. 23, 1969 Brief description of the drawings FIG. 1 is a plan view of a tilt plate latch mechanism incorporating the present invention but with parts broken away and parts shown in section as seen along the line 11 of FIG. 2;

FIG. 2 is a vertical sectional view taken along the line 22 of FIG. 1 showing a latch pin being gripped and held by tilt plates;

FIG. 3 is a view similar to FIG. 2 but showing the latch in released condition;

FIG. 4 is a detailed perspective view of the rotary abutment;

FIG. 5 is a perspective view of one of the tilt plates; and

FIG. 6 is a perspective view of a leaf spring employed in the present invention.

Description of the preferred embodiment The invention described herein will be described, by way of example, as a latch for an automobile trunk lid, releasable by a key lock device. It is to be understood, however, that the specific form described is by way of illustration only and that the latch mechanism may be employed in any other suitable environment.

In the drawings, numeral 2 (FIGS. 2 and 3) indicates a portion of an interior structural element fixed to a trunk lid and on which a latch pin 4 is mounted. The latch pin 4 is shown as having a threaded end portion 6 extending through an elongated opening 8 in the structure 2 whereby it may be adjusted by a limited amount in at least one direction, preferably parallel to the plane of the drawing.

Numeral 10 indicates a portion of an automobile frame defining the trunk opening adjacent the rear edge of the trunk lid. To the frame portion 10 a housing structure 12 is afiixed by any suitable means, such as the bolts 14. The housing 12 is shown as comprising a bottom portion 16 defining a well or compartment 18 seated in an opening 19 in frame member 10 and an upper outwardly directed peripheral flange 20. The top of the housing 12 is defined by an upper plate 22 having a peripheral flange portion 24 overlying the flange 20. The flanges 20 and 24 are provided with aligned elongated openings 26 (see FIG. 1) through which the bolts 14 pass and is held together by tabs 27 integral with flange 20 and folded over flange 24. Thus, the housing 12 may be adjusted on the frame 10 in one direction, preferably perpendicular to the direction of adjustment of the latch pin 4, already described. In this manner the parts may be adjusted to bring the latch pin 4 into substantially precise alignment with guide means 26 and 28 formed on the housing 12 and which effect very precise guidance of the latch pin 4 through the housing 12, all as described in detail in my copending application, previously identified.

A plurality of tilt plates 30 are stacked one upon the other in the housing 12 rather loosely therein whereby they may be readily shifted laterally to accurately align their respective apertures 32 with the guided latch pin 4. As described in my copending application, the tilt plates 30 are preferably softer than the latch pin 4, the latter preferably being of a hardened metal. As is also described in that copending application, the openings 32 are formed quite accurately to the size and the shape of the latch pin 4 so that only slight relative tilting will cause each of the plates to individually bind against the pin 4. The guide means 26 and 28 prevent the latch pin from tilting relative to the housing 12 and thus the as sembly ensures efiicient and firm latching action.

Within the housing 12 and below the plates 30, there is positioned a generally arch-shaped leaf spring 34, the ends of which bear against the bottom housing wall 12 and an intermediate portion of which bears against the an abutment which will be described later. Thus, the upward force of the spring 34 holds the plates 30 in engagement with the abutment and also urges them to tilt about that abutment, all in a manner well known in this type of latch. The spring 34 is provided with an elongated opening 36 of sufficient size to provide clearance for the latch pin 4, irrespective of which end of the spring is positioned at a particular end of the housing 12.

The abutment previously referred to is identified in FIG. 2 as a nose or abutment portion 38 on a shaft element 40. The lower housing member 16, and particularly the flange portion 20 thereof, is shaped to define aligned generally semi-cylindrical recesses 42 and the upper plate 22 of the housing is likewise formed with generally semicylindrical recesses 44 which, with the recesses 42, define a journal or bearing for the shaft 40. As shown in FIGS. 1 and 4, the shaft 40' is provided with an annular recess 46 adjacent one end thereof which recess is engaged by a retaining ring or rib 48 (see (FIG. 1) to retain the shaft 40 against axial displacement in its bearing. As shown in FIG. 4, the shaft 40 is cut away at 59 throughout a length thereof sufiicient to extend the entire width of the plates 30 therebelow. The cut-away reduces that portion of the shaft to a semi-cylindrical sectional shape with a flat surface 52 passing substantially through the axis of the shaft. In FIG. 2, the shaft 40 is shown in a rotary position wherein the surface 52 is substantially perpendicular of the plates 30 in which position the nose or abutment portion 38 extends toward the plates 30 and defines a fulcrum abutment about which the plates are pivoted by the spring 34. Since the shaft 40 is rotatable in its supporting bearing, it can be rotated to the position shown in FIG. 3 wherein the flat surface 52 faces the plates 30 and in which position the nose or abutment portion 38, is, in effect, withdrawn from the plates 30. As is evident from FIG. 3, the upper plate 22 of the housing 12 is configured to define downwardly facing surfaces or stop means, such as indicated at 54 and 56 in FIG. 3, which are coplanar with the flat surface 52 when the latter is in the FIG. 3 position. Thus, when the shaft 40 is turned to the FIG. 3 position, there is no effective fulcrum abutment against which the plates 30 can pivot. Any upward forces acting on those plates, including the force of spring 34, causes the plates to lie fiat against the surfaces 52, 54 and 56, and in which position those plates are perpendicular to the axis of latch pin 4 and the latch is thus released.

It will be apparent that counterclockwise rotation of the shaft 40, as seen in FIG. 2, will displace the bearing point 38 laterally to the right and the upward force exerted by the plates 30 on that hearing point will apply a torque to the shaft 40' assisting in rotating the same to theposition of FIG. 3. Preferably, the edges of the surface 52 are slightly rounded to merge smoothly with the periphery of the shaft 40 and eliminate sharp edges which would increase the force necessary to initiate rotation of the shaft. In the position of FIG. 2, the upward force exerted by the plates 30 on the abutment 38 is so nearly in line with the axis of the shaft 40 that no appreciable rotary moment is applied to the shaft.

It has been found that extremely high forces tending to withdraw the pin 4 from the tilted plates 30 are successfully and efficiently resisted and that a relatively small torque applied to the shaft 40 will cause rotation of the same to the release position of FIG. 3.

As suggested in FIG. 1, rotation of the shaft 40 may be effected and controlled by a suitable lock mechanism and in the drawings numeral 60 indicates a schematically illustrated rotary barrel of a conventional tumbler type of key lock. The rotary barrel 60 may be provided with any suitable projection or link 62 extending into a slot 64 formed in an end of the shaft 40 to thereby rotatably connect the shaft to the barrel 60'. A retaining ring 66 is shown for the purpose of preventing inadvertent lateral movement of the link 62 out of the slot 64. The key operated lock, which includes the barrel 60, may be the customary key lock provided on trunk lids and by insertion of a proper key therein, the barrel may be easily turned to thereby rotate the shaft 40 -to an unlocking position. As long as the barrel 60 is left in such position, the trunk lid cannot-be latched in closed position since the plates 30 are held in the unlocked position of FIG. 3. Preferably, the lock'and shaft 40 are returned to the FIG. 2 position before the trunk lid is closed, and thus only a slight torque need be applied to the shaft 40, only suflicient to overcome the resistance of spring 34, to tilt one edge of the plates 30 downwardly. Thereafter closing of the trunk lid will project the latch pin 4 through the openings 32 and the initial binding effect will result in further downward movement of the plates to remove their left hand end portion, as seen in the drawings, from stop 54 and thus lock. the pin against upward withdrawal. Obviously, vibration or other vertical forces will effect tightening of the trunk lid and since it is customary to provide resilient seals between the trunk lid and vehicle frame, those resilient seals will be firmly compressed and will maintain an upward force on the latch pin 4 ensuring holding the plates 30 in the desired tilted position.

While a single specific embodiment of the invention has been shown and described herein, it is to be understood that modifications may be resorted to and that the improved latch release may be adapted to tilt the plate in latch mechanisms employing even a single tilt plate, with or without a pilot or guide means 26 and 28. Furthermore, the latch of the present invention is susceptible to use in other environments than automotive trunk lids.

I claim:

1. In a tilt-plate latch having a support, fulcrum abutment on said support, an apertured tilt plate, and spring means laterally displaced from said abutment toward the aperture in said tilt plate and urging said plate toengage said abutment and tilt thereon to frictionally bind a latch pin in said aperture, the improvement comprising: means movably mounting said abutment on said support to withdraw the same from fulcruming relation to said plate and thereby permit said plate to move to a nontilted position to release the latch pin.

2. A latch as defined in claim 1 wherein said support defines stop means laterally displaced from said abutment; engageable by said plate upon withdrawal of said abutment for enforcing return of said plate to non-tilted position, by said spring means.

3. A latch as defined in claim 1 wherein said abutment comprises a member rotatably mounted on said support and having an abutment portion extending toward said plate whenv said member is rotated to one position and which is turned to extendin a different direction when said member is rotated to another position.

4. A latch as defined in claim 3 wherein said abutment portion is eccentric to the axis about which said member rotates whereby force applied thereto by said plate extends substantially through said axis when said member is in said one position and assists in rotating said member toward said other position after initial rotation out of said one position. i

5. A latch as defined in claim 1 wherein said abutment comprises a substantially cylindrical shaft member journalled on said support about an axis substantially parallel to an adjacent surface of said plate; the portion of said shaft member opposite said adjacent surface being of semi-cylindrical sectional shape having a generally flat surface containing said axis whereby to serve as a fulcrum abutment only when said flat surface is positioned generally perpendicular to said plate and whereby said abutment is withdrawn when said flat surface faces said plate.

6. A latch as defined in claim 5 wherein said support References Cited defines fixed stop means substantially coplanar with said fiat surface when said flat surface faces said plate. UNITED STATES PATENTS 7. A latch as defined in claim 1 wherein said spring 1,854,386 4/1932 Werth 292-306 means bears On that face of said plate opposite the face 5 2,169,875 8/1939 Fanning 292,406 engageable with said abutment and in a region laterally displaced from said abutment toward said aperture; and 24783O4 8/1949 Mulsow 292-349 stop means on said support engageable by said plate upon EDWARD J. MCCARTHY Assistant Examiner withdrawal of said abutment for enforcing return of said plate to non-tilted position, by said spring means, said 10 MARVIN CHAMPION, 'y EXamlIlfil stop means including a portion on the other side of said region from said abutment.

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