US3208781A

US3208781A - General purpose latch

Info

Publication number: US3208781A
Application number: US273474A
Authority: US
Inventors: Walter T Appleberry
Original assignee: Douglas Aircraft Co Inc
Current assignee: Douglas Aircraft Co Inc
Priority date: 1963-04-16
Filing date: 1963-04-16
Publication date: 1965-09-28
Anticipated expiration: 1982-09-28

Description

Sep 28, 1965 w. 'r. APPLEBERRY 3,208,781

GENERAL PURPOSE LATCH Filed April 16, 1963 2 Sheets-Sheet l :Tl 4: eFl

INVENTOR.

WJEZ TAf AEBEZEy Mzg/ Sept- 1965 w. T. APPLEBERRY 3,208,781

GENERAL PURPOSE LATCH Filed April 16, 1963 2 Sheets-Sheet 2 il lul illl" 11g; 1

INVENTOR.

BY MIX 6d United States Patent Calif., as-

Santa This invention relates to latch assemblies and relates more particularly to those types of latch assemblies which employ pivotal levers.

Ordinary latches known heretofore and used in connection with drawers, compartment and cabinet doors, and the like types of closures, generally utilize lever structures provided with pivot pins, the pivot pins serving as the axis of rotation of the lever as well as a means for holding the lever in place. Several manufacturing steps are required to produce levers having pivot pins, and considerable effort and special tools are required for installation thereof. A latch which is sometimes more economical to produce uses a lever which is not pinned at its axis or axes of rotation, but is allowed to rotate freely and is merely held against sliding by guides. The elimination of pivot pins furthers the economy of manufacture of the lever, but necessitates the use of other means for securing the latch in place. Specially shaped springs and brackets have been produced which are fastened to a closure front or other structure to which the latch is mounted, but the difiiculty and expense of installation is often even greater than that required in the case of latches with pinned types of levers. Furthermore, the rotation of the levers in pinless latches is frequently accompanied by substantial friction and wear, and the latches often do not operate smoothly.

In accordance with one feature of this invention, latches with pinless levers are provided which are economically manufactured and which may be quickly and economically installed, without the use of special tools. The foregoing is accomplished through the use of levers which are easily insertable in apertures formed in closure fronts, or the like, and which are held in place by means of stacking, which is the limited compressibility property of certain types of springs.

In accordance with another feature of this invention, friction and accompanying wear often associated with pinless latch levers is reduced by reducing the net force on a lever when it is rotated, so that it bears lightly against the guides which prevent sliding. In accordance with this invention, the net force on the lever is reduced by so locating the handle portion of the lever that force applied to it in releasing the latch counters the force exerted by a biasing spring, and the net force on the lever is therefore held to a minimum.

In accordance with another feature of this invention, latch levers are provided which are economically manufactured as by the process of stamping or by slicing sections from an extrusion, and which operate with simple springs such as coil springs. In ordinary latches, springs are held to levers by pins riveted or otherwise applied to the levers. This results in levers of uneven cross-section that cannot be easily manufactured as by extrusion or stamping. In this invention, projections of constant crosssection are provided for holding springs and the lever is of constant cross-section.

The incorporation of the several defined features of this invention enables the economical manufacture of a latch which may be installed in connection with closures in several seconds, and without the need for tools of any type. Furthermore, once installed, the lever cannot be accidentally removed and it operates smoothly and with little wear.

"ice

Accordingly, one object of the invention is to provide a latch having features of novelty enabling easy installation thereof.

Another object of the invention is to provide a latch having characteristics enabling such installation without the use of tools.

A further object of the invention is to provide a latch which is securely held in place merely by the stacking action of a spring.

A still further object of the invention is to provide a latch using a spring biased pinless lever, which operates smoothly and with little friction or wear.

Still another object of the invention is to provide a latch using a spring biased pinless lever of constant crosssection, which can securely retain a simple spring.

Other objects and a more complete understanding of the invention will be had from the disclosures in the following detailed specification, appended claims, and accompanyin g drawings, wherein:

FIGURE 1 is a perspective view showing one embodiment of the present invention as employed with a closure for a simple container;

FIG. 2 is an enlarged side elevational sectional view of one embodiment of the present latch operable by the application of a pulling force, and which is shown in operation in FIG. 1.

FIG. 3 is a side elevational view of the latch of FIG. 2 shown during assembly thereof in a plate;

FIG. 4 is a side elevational view of the latch of FIG. 2 illustrating the stacking action of the spring of the latch;

FIG. 5 is an exploded pictorial view of another embodiment of the invention adapted for use with a semiflush lever;

FIG. 6 is a partially sectional side elevational view of the latch of FIG. 5;

FIG. 7 is a side elevational view of the latch of FIG. 5 shown during assembly; and

FIG. 8 is a partially sectional side elevational view of a further embodiment of the invention.

With reference to the drawings, FIG. 1 illustrates a container B having a cover C which includes a latch assembly L. The latch assembly L serves as a handle for applying force to open and lift the cover C and as a locking device for holding the cover C in a closed position. The latch assembly is positioned near one edge of the cover C on a side opposite a pair of hinges H upon which the cover pivots. The latch L includes a lever with a hook portion P which engages a strike 20 fastened to the inside of the container. The latch assembly shown in FIG. 1 is shown in greater detail in FIG. 2.

In general, the embodiment shown in FIG. 2 includes an integral lever 12 which extends through a generally rectangular hole 14 in a plate 16, the plate being the cover of any suitable closure. A spring 18, disposed between the lever 12 and plate 16, biases the lever in a direction wherein a hook 19 of the lever is urged toward a strike 20 carried by the container B.

The lever 12 further comprises a handle portion 22 located in spaced relationship to an outer surface 24 of the plate 16 and an elongated pivot portion 26 extending at right angles to the handle portion 22 and passing through the hole 14 in the plate 16. The elongated pivot portion has a notch 28 in one side, the notch being adapted to receive the edge of the plate 16 adjacent the hole 14. A lip 30 is provided on a side of the pivot portion 26 opposite the notch 28, the lip lying beneath and abutting an inner surface 32 of the plate. The hook 19 is formed at the free end of the pivot portion 26 opposite from the handle portion 22. An integral elongated coil spring holder 34 extends from the pivot portion 26 at a location intermediate the notch 28 and hook 19.

As described, the side of the lever in which the notch 28 is located is held to the plate 16 by an edge of the plate which passes within the notch. The notch 28 has three sides, an outer side 38 which abuts the outer surface 24 of the plate, a base 40 which is perpendicular to the outer side 38 and which abuts the edge of the plate 16, and an inner side 42 meeting the base at an obtuse angle and extending away from the inner surface 32 of the plate. The outer side 38 and base 40 meet at a corner 44 and the base and inner sides 40 and 42 meet at a corner 46. When the latch is operated, the edge of the plate 16 contacts one of the

sides

38 or 40 near one of the

corners

44 or 46 and the lever pivots about the point of contact (which may shift during the pivoting).

The lever 12 is prevented from moving outwardly by the lip 30 on the side of the lever opposite the notch, which lies against the inner surface 32 of the plate. The lever is biased so that the lip 30 normaly engages the plate, by the torque on the lever resulting from the force of the coil spring 18 on the spring holder 34 and the restraining force of the plate on the outer side 38 of the notch 28. A stepped portion 48 located outwardly of the lip 30 abuts the edge of the plate 16 at a point opposite the notch 28 and prevents the lever from moving laterally. This stepped portion 48 is rounded to provide clearance and allow the lever to pivot.

The biasing force on the lever 12 is obtained through the use of a wide coil spring 18 which exerts force against the coil spring holder 34. The coil spring is held in place by two projections or bosses 50 protruding from the spring holder 34. The coil spring 18 has a sufficient width-toheight ratio that it does not buckle. Accordingly, when one end of the spring is placed over the bosses 50, the other end rests securely against the plate 16 without any holding bosses or recesses in the plate. Inasmuch as no spring holding device must be attached to the plate 16, the installation of the latch is accomplished with a minimum of effort and expense.

Before the latch is installed, a generally rectangular aperture 14 is formed in the plate 16. In the installation, as shown in FIG. 3, the lever 12 is inserted through the plate 16 from the innermost surface 32, the handle portion 22 being inserted first. The lever is so shaped that in order to engage the edge of the plate 16 within the notch 28 of the lever, the lever must be pivoted in a direction wherein the handle 22 moves away from the plate 16, which direction shall be defined as the clockwise direction, and far enough that the spring holder 34 closely approaches the innermost surface 32. Once the notch 28 receives the plate edge, the lever 12 is turned counterclockwise until the lip 30 contacts the inner surface 32 of the plate. The coil spring 18 is then slightly compressed and placed over the bosses 50.

The coil spring causes the lever to be biased counterclockwise so that the hook 19 remains engaged with the strike 20. In order to release the latch, upward force is applied to the handle portion 22, which causes the lever to pivot in a clockwise direction and release.

The lever 12 is limited in its clockwise pivoting by the stacking of the coil spring 18. The condition of stacking, shown in FIG. 4, relates to the mutual contact of the coils of the spring which prevents any further compression. Stacking of the spring 18 occurs before the lever 12 can be pivoted far enough that the notch is disengaged from the plate 16. The stepped portion 48 abuts the edge of the plate 16 and prevents the disengagement of the notch 28 from the plate 16, until the lever 12 is pivoted so far clockwise that the spring holder 34 comes close to the plate 16 and the stepped portion 48 is clear of the plate. Thus, disassembly of the latch requires the prior removal of the coil spring 18, which cannot happen accidentally since the spring is held by the bosses 50. However, the latch may be disassembled with ease by compressing the spring 18 and sliding it out from between the spring holder 34 and plate 16, and then pivoting the lever 12 clockwise until the notch 28 no longer holds the plate 16.

The assembled latch serves to hold a cover or the like closed, by means of the engagement of the hook 19 with the strike 20. To release the latch, upward force is applied to the handle portion 22. The location of the handle 22 is such that when it is grasped in a normal manner, the force applied to the handle is in a direction which is largely in line with the direction of force applied by the coil spring 18 to the coil spring holder 34. As the latch is released, the two forces substantially cancel one another, and as a result there is only a small net force on the lever. As a consequence of the small net force on the lever, the areas surrounding the

corners

44 and 46 of the notch 28 bear lightly against the edge of the plate 16 as the lever turns. This results in low friction and permits the latch to be released smoothly and with little wear on the notch 28 or the edge of the plate 16.

Friction and wear are reduced at the notch 28 where the lever pivots, not only through the reduction of the net force on the .lever as described hereinbefore, but also through the proper configuration of the notch 28. The innermost side 42 of the notch has a slope so that it extends away from the plate 16. This causes the point of contact of the lever 12 and plate 16 to locate in an area near one of the

inner corners

44 and 46. Very little sliding occurs at these areas when the lever pivots and therefore little friction is produced.

An integral lever of constant cross-section is utilized herein in order to provide a lever that may be economically manufactured. A lever of constant cross-section may be manufactured by producing an extrusion having the crosssection of the desired lever, and thereafter slicing or otherwise cutting the extrusion to obtain levers. Accordingly, all portions of the lever have engaging or interacting parts which extend from the sides of the lever and have constant cross-sections, such as the notch 28, lip 30, spring holder 34 and hook 19.

The embodiment shown in FIGS. 5, 6 and 7 is adapted for use where a latch is required that is substantially flush with the surface of a plate in which it is installed. This embodiment of the latch includes a lever 52 which extends through a pan housing 54, and a coil spring 56 between them. The pan 54 is channel-shaped and has a bottom 57, open ends 58 and 6t and flanges 62 extending outwardly from the open side of the channel opposite the bottom 57. The lever 52 includes a handle portion 64, a hook portion 66 extending substantially perpendicular to the handle portion, and a center portion 68 therebetween. The spring 56 is positioned between the bottom 57 of the pan and a hollowed portion 78 in the handle portion of the lever. The latch is useful for holding in a closed position a cover or the like to which the latch is fixed, such holding being accomplished by the engagement of the hook portion 66 with a strike 72 fixed to a closure or the like.

This embodiment of the invention is adapted to be installed within a generally rectangular opening in a sheet such as a hole 74 in a plate 76. The pan 54 is situated within the rectangular hole 74 and the flanges 62 rest upon the surface of the plate 76.

Most of the handle portion 64 of the lever lies within the pan 54. An extending portion 78 of the lever projects through the end 58 of the pan and the lever center portion 68 extends through the end 60 of the pan. The hook portion 66 extends downwardly and engages a strike 72.

The spring 56 between the lever and pan serves to bias the handle portion 64 of the lever away from the pan. The lever is held on one side of the plate 76 by the extending portion 78 and shoulder 80 which rest on the inner side 82 of the plate 76. The lever is held against lateral movement by a stepped handle boss 84 and a protrusion 86 which abuts the edges of the metal sheet surrounding the hole 74. A hollow 88 formed by the boss 84 and protrusion 86 serves to indicate that the handle portion 84 should be pushed to operate the latch.

The latch is installed in the hole 74 in a manner shown in FIG. 7. The pan 54 is partially inserted through the hole 74 from above the plate 76, and placed so that a cut-away portion 90 of the pan rests on one edge of the plate 76. The handle portion 64 of the lever is inserted [from the inner side of the plate and through the end 60 of the pan 54 to a position wherein the extending portion 78 projects through the end 58 of the pan and lies against the inner side 82 of the plate. The pan 54 is then inserted the rest of the way into the hole. Thereafter, the coil spring 56 is compressed and inserted through the end 58 of the pan, and pushed into the hollowed portion 70 of the lever.

In order to remove the lever 52, the end of the pan including the cut-away portion 90 must be lifted so that the cut-away portion rests on the top of the plate 76 in a manner similar to the method of installation of the latch shown in FIG. 7. However, when the cut-away portion 90 rests on the plate 76, the handle portion 64 of the lever almost contacts the bottom 57 of the pan 54. If the hollowed portion 70 is not too deep, the coil spring will stack before the pressing portion 64 contacts the bottom 57 of the pan, and the pan 54 cannot be lifted high enough for disassembly of the latch. The latch can be disassembled by compressing the coil spring 56 and withdrawing it from the end 58 of the pan.

Although the stacking of the spring prevents accidental removal of the latch, this feature is not necessary. The pan 54 itself is not lifted when the latch is operated, so there is a small likelihood that it would be lifted and the latch disassembled accidentially. However, the stacking of the spring 56 does prevent undesired disassembly by those who might tamper with the latch and lift the flanges 62 away from the plate 76.

To release the latch of FIGS. 5, 6 and 7, the handle boss 84 is depressed as shown in FIG. 6. When sufficient force is exerted to overcome the force of the spring 56, the bandle portion 64 moves toward the bottom 57 of the pan and the lever pivots in a direction herein defined as counterclockwise. The lever may rock on the rounded shoulder 80 or on the inner radius 92 of the center lever portion 68, depending on the location at which force is applied. The line 55 in FIG. 6 represents the centerline of the spring 56. If unlatching force is applied to the right 61 of the centerline, more unlatching force must normally be applied than is exerted by the spring 56 in order to provide a net counterclockwise torque. In that case, the net force on the lever 52 will push it in a downward direction and it will pivot about the inner radius 92 of the center lever portion 68. Conversely, the application of unlatching force to the left side 59 of the spring centerline 55 normally results in the net force on the lever being upward and the lever rocking on the rounded shoulder 80.

When the lever pivots counterclockwise, the hook portion 66 disengages from the strike 72. The plate 7 6, which may be a cover, is lifted by upward force applied to a finger hold -91, which is an indentation formed in the side of the pressing boss 84. Typically, the latch is released by means of pressure applied by the thumb of a person to the handle boss 84, and the plate 16 is pivoted away from a closure by means of the application of a pulling force applied by a finger to the finger hold 91, both of these forces being applied simultaneously.

The spring'56 is located inwardly of the handle boss 84 so that the force exerted on the handle boss in opening the lever is approximately equal to the force exerted by the spring. This provides for a minimum net force on the shoulder 80 or inner radius 92 when the lever 52 pivots, and the friction and wear on the lever are very small. In order to promote economy of manufacture, the lever is integral and of constant cross-section.

The embodiment shown in FIG. 8 is adapted for use in pull drawers, and other similar applications. This embodiment includes a U-shaped handle 94 having two

legs

96 and 98 which are adapted to be held against a drawer front 100 or the like and are held in place by screws 102 or the like. One leg 96 is provided with a 6 recess or slot 104 for receiving an integral latch lever 106.

The lever 106 includes an operating portion 108 which extends partially into the slot 104 in the leg 96 and which is integral with a latching portion 110 having a hook 112. The lever 106 is held in place by edges of the sheet adjacent the hole 107; the edge 114 of the plate holds one side of the lever 106 and a rounded pivot portion 116 formed in the handle leg 96 holds the opposite side of the lever. A protrusion 117 on the leg 96 is inserted through the plate 100 to position the handle 94 over the plate and insure sufficient clearance between the edge 114 and the lever 106.

The lever 106 holds the drawer in a closed position by means of a hook 112 which engages a strike 118 fixed to the drawer holder or stand in which the drawer slides. The lever 106 is urged in a direction whereby the hook 112 is biased toward a position of engagement with the strike 118 by a coil spring 120 and the restraining force of the edge 114 of the drawer front. A stepped portion 121 on the lever abuts the outer surface 101 of the drawer front adjacent the edge 114, and limits pivotal movement of the lever in the biased direction. The coil spring 120 has two ends, one of which is held within a notch 122 in the lever, the other being disposed about a boss 124 which projects from the base of the recess 104 in the leg 96.

The lever is operated so as to release the hook 112 from the catch 118 by the application of force to the projection 126 of the lever. Pressing the projection 126 moves the operating portion 108 against the force of the spring 120. A semicircular notch 128 in one edge of the lever engages the rounded pivot portion 116 and serves as a bearing to permit the lever to be pivoted in an unlatching direction.

In order to assemble the latch assembly of FIG. 8, the lever 106 is placed within the slot 104 in the leg 96 prior to attachment of the

legs

96 and 98 to the drawer front 100. The lever is so positioned that the rounded pivot portion 116 of the leg 96 is received within the notch 128. The lever is then pivoted in a direction which moves the operating portion 108 away from the bottom of slot 104 and the coil spring 120 is slipped over the boss 124 and into the notch 122. The lever 106 and the leg 96 are moved in a direction to overcome the force of the spring which tends to separate them, and the ends of the

legs

96 and 98 of the U-shaped handle are placed against the drawer front 100. Screws 102 extend through the drawer front and threadably attach to the

legs

96 and 98 to hold the handle in place.

It can be seen that in the operation of this latch, as in the operation of the other latches described hereinbefore, the frictional resistance which must be overcome when the lever 106 pivots is relatively small. This is due to the fact that the projection portion 126 is so situated that unlatching force is normally applied substantially in line with the direction of force exerted by the spring 120 so that the net force on the lever is small.

It can be appreciated from the three embodiments described hereinbefore that a latch using a pinless lever may be provided which has a minimum of frictional resistance, by so locating a release member that the net force on the lever is substantially zero. This feature is displayed by all three embodiments shown. By providing such a lever of constant cross-section, a latch is obtained that may be economically manufactured as by slicing sections from an extrusion. Other innovations shown in the particular described embodiments, especially the utilization of the stacking property of coil springs to prevent accidental disassembly of the latches, ensure that the latches may be easily installed, will operate smoothly and with a minimum of service problems, and will present the utmost in efficient design and operation. It should be noted that although coil springs are shown in each of the three embodiments, various other types of springs may be used instead, many of which display the property of stacking.

Having thus described the invention and the several embodiments thereof, it is desired to emphasize the fact that many further modifications may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

1. A latch adapted to be received in an aperture in a plate comprising:

a lever having a notch adapted to receive and rotate on an edge surrounding said aperture in said plate;

a coil spring holder on said lever for holding one end of a coil spring;

a stackable coil spring having one end abutting said coil spring holder and an opposite end abutting said plate; and

a protrustion extending from said lever from a point substantially opposite said notch, the height of said protrusion being great enough that it abuts the edge of said plate surrounding said hole when said lever is pivoted so far that said spring stacks, said protrusion having a sufiiciently small height that said lever is rotatable far enough, when said spring is not placed on said coil spring holder, that said protrusion is clear of said edge of said plate.

' 2. A latch assembly adapted for installation in a plate means having an aperture forming an edge, comprising:

a lever having a notch formed in a side thereof, said notch adapted to receive and rotate about said edge of said aperture;

a hook means formed at one end portion of said lever;

an elongated spring holder formed on said lever between said notch and said hook means and extending substantially perpendicular to said lever from the same side thereof on which said notch is formed;

spring means extending substantially perpendicular to said spring holder and to a surface of said plate means, and abutting a surface of said plate means, said spring means being stackable so that the movement of said spring holder towards said plate means, when said lever is rotated, is limited by stacking of said spring means; and

a shoulder on said lever, said shoulder disposed on a lever portion substantially opposite said notch, the height of said shoulder in a direction substantially circumferential about said notch being great enough that when said lever is rotated so that said spring means stacks, a portion of said shoulder abuts a portion of said edge of said plate means, to prevent removal of said lever from said plate means;

the height of said shoulder being limited so that said shoulder is clear of said edge of said plate means when said spring means is not present and said lever is rotated so that said spring holder is made to approach as closely as possible to said plate means', to enable removal of said'lever from said plate means.

3. A latch lever comprising:

a handle portion;

an elongated pivot portion having a first end extending substantially at right angles to said handle portions;

a notch formed on one side of said pivot portion;

a hook formed on a second end portion of said pivot portion which is opposite said handle portion;

a stepped portion formed on said pivot portion on a side thereof opposite said notch, said stepped portion located approximately opposite said latch;

a lip formed on said pivot portion adjacent said stepped portion, said lip extending past said stepped portion; and

a spring holder extending from a spring holder point located on the same side of said pivot portion as said notch and located between said second end of said portion and said notch, said spring holder extending substantially perpendicular to said pivot portion and to a distance therefrom greater than the distance between said spring holder point and said notch, whereby said spring holder is adapted to hold a coil spring of a large diameter to length ratio.

4. A latch lever as defined in claim 3 including:

projections formed on said spring holder;

a coil spring adapted for disposal about said projections, said coil spring compressible before stacking, to a length which is smaller than its diameter whereby said spring is adapted to be stably held between a flat surface having no special spring holding means thereon and said spring holder.

5. A lever assembly adapted for rotatable installation in an aperture in a plate comprising:

a lever;

a notch formed in a side of said lever for engaging the edge of said aperture;

spring holding means on said lever, located a predetermined distance from said notch, said spring holding means adapted to hold one end of a stackable spring means;

a stackable spring means having a first end engaged with said spring holding means and a second end adapted to engage a stationary object;

a shoulder formed on said lever at a position approximately opposite said notch, said shoulder having a height which is great enough that when said lever is rotated so that said spring means stacks said shoulder abuts the edge of said aperture thereby preventing the removal of said lever from said aperture, said height being limited so that when said spring means is not present and said lever is rotated to a position past the position where said spring stacks when it is present, said shoulder does not abut said edge of said aperture thereby enabling the removal of said lever from said aperture.

References Cited by the Examiner UNITED STATES PATENTS M. HENSON WOOD, JR., Primary Examiner. THOMAS J. HICKEY, Examiner.

Claims

1. A LATCH ADAPTED TO BE RECEIVED IN AN APERTURE IN A PLATE COMPRISING: A LEVER HAVING A NOTCH ADAPTED TO RECEIVE AND ROTATE ON AN EDGE SURROUNDEING SAID APERTURE IN SAID PLATE A COIL SPRING HOLDER ON SAID LEVER FOR HOLDING ONE END OF A COIL SPRING; A STACKABLE COIL SPRING HAVING ONE END ABUTTING SAID COIL SPRING HOLDER AND AN OPPOSITE END ABUTTING SAID PLATE; AND A PROTRUSTION EXTENDING FROM SAID LEVER FROM A POINT SUBSTANTIALLY OPPOSITE SAID NOTCH, THE HEIGHT OF SAID PROTRUSION BEING GREAT ENOUGH THAT IT ABUTS THE EDGE OF SAID PLATE SURROUNDING SAID HOLE WHEN SAID LEVER