US3016103A

US3016103A - Stepladder having adjustable legs thereon

Info

Publication number: US3016103A
Application number: US12823A
Authority: US
Inventors: Lewis O Studer
Original assignee: WEATHER SEAL Inc
Current assignee: WEATHER SEAL Inc
Priority date: 1960-03-04
Filing date: 1960-03-04
Publication date: 1962-01-09
Anticipated expiration: 1979-01-09

Description

STEPLADDER HAVING ADJUSTABLE LEGS THEREON Filed March 4, 1960 L. O. STUDER 3 Sheets-Sheet 1 INVENTOR. LEAK 5 17'571/27511? L- o. STUDER 3,016,103

STEPLADDER HAVING ADJUSTABLE LEGS THEREON Jan. 9, 1962 3 Sheets- Sheet 2 Filed March 4, 1960 mmvrox LEA/f5 0572/2751? Jan. 9, 1962 L. o. STUDER 3,016,103

STEPLADDER HAVING ADJUSTABLE LEGS THEREON Filed March 4, 1960 3 Sheets-Sheet 3 [NV EN TOR. LE [1/5 '5' 71/1751? United States Patent 3,016,103 STEPLADDER HAVING ADJUSTABLE LEGS THEREON Lewis 0. Studer, Doylestown, Ohio, assiguor to Weather- Seal, Inc., North Barberton, Ohio, a corporation of Ohio Filed Mar. 4, 1960, Ser. No. 12,823 11 Claims. (Cl. 182126) The present invention relates to stepladders, especially to a novel and improved stepladder having a plurality of extensible and adjustable legs thereon for adapting the stepladder for firm support on uneven ground or other support means.

Heretofore there has been some work done in the provision of extensible members on ladders so that the two support legs of the ladder will be variable to conform to an irregular support surface, or ground. However, there has been very little, if any, work done in the field of stepl'adders to permit them to accommodate themselves to irregular or uneven support surfaces. Insofar as I am aware, there is no construction now available for stepladders to permit their safe use on uneven support surfaces and many accidents result from use of stepladders under unsafe conditions.

It will be realized that in various instances of use of stepladders, it would be very desirable to have extensible legs thereon, so that the stepladder could be adjusted for safe support action and use on uneven or irregular support surfaces. Obviously, the problem of providing extensible legs on a stepladder, rather than a ladder, involves a more complex problem than with a two legged ladder.

Universal adjustment must be provided on all four legs of astepladder for a safe, sturdy, level support of the stepladder when used on irregular support means.

The general object of the present invention is to provide a novel and improved stepladder of the class described and characterized by the provision ofex'tensions for all four legs of the stepladder, which extensions will automatically and readily move to conform to irregular support surfaces provided for the stepladder and provide a proper level positioning of support means in the stepladder.

Another object of the invention is to provide a stepladder with extensible legs wherein locked, operative positions are provided for the extension legs when a stepladder is in use, and where release positions for all of the extension legs can be provided by movement of a unitary control means in the stepladder.

A further object of the invention is to provide a stepladder having automatically adjustable extension legs thereon, and where the extension legs can be locked in given positions when the stepladder is being carried to avoid undesirable movement of the extension legs as the stepladder is being carried or moved from one position to another.

Further objects-of the invention are to provide a lightweight, sturdy type of a stepladder, having extension legs thereon; to provide an uncomplicated control and lock system for extension-legs in a stepladder; to use the brace or spreader means in a stepladder for providing release positions for the leg extensions when the stepladder is beingadjusted to a support surface, and providing locked positioned when the stepladder is in acompletely collapsed position for storage or movement; to provide a plurality of individual lock members associated with the individual legs of a step-ladder, and with individual control members being slidable or movable longitudinally of the legs of the stepladder for controlling action of the lock members; to control the operation of the control rods and" lock members by means operatively associated with the bucket-support shelf and support arms of the stepladder; andto provide a control meansfor extension legs of a step- 3,016,103 Patented Jan. '9, 1962' 2 ladder having relatively few parts therein, which parts are of a compact and relatively inexpensive construction. I

The foregoing and other objects and advantages of the invention will be made more apparent as the specification proceeds.

Attention now is directed to the accompanying drawings, wherein one currently preferred embodiment of the principles of the invention is shown, and wherein:

FIG. 1 is a front elevation of the stepladder of the in vention shown operatively positioned;

FIG. 2 is a side elevation of the stepladder of FIG. 2;

FIG. 3 is an enlarged side elevation, partially shown in vertical section, of the stepladder of FIG. 1, and with the ladder rungs thereon being removed, which section is taken in the stepladder facing inwardly toward the left side support legs of the stepladder;

FIG. 4 is a fragmentary section, like FIG. 3, only enlarged and'with the bucket-shelf and support arms removed, showing operative conditions and actions of control members in the stepladder;

FIG. 5 is a view similar to FIG. 4, but with the stepladder components being shown in their collapsed, or storage position;

FIGS. 6, 7 and 8 are fragmentary vertical sections of the lower left, front portion of the stepladder of FIG. 1, andwith the positions of the extension legs and control means being shown, respectively, for the ladder in closed, ladder open with extension legs unlocked, and ladder open and legs in lockedpositions;

FIG. 9 is a vertical section of a fragmentary portion of the right rear support leg and associated means, showing the lock and control means in operative, or locked positions;

FIG. 10 is a fragmentary enlarged vertical section taken on lines 1010' of FIG. 5, showing some of the control members in the stepladders; and

FIG. 11 is a fragmentary enlarged vertical section, taken through the rear legs of the stepladder at the connection between the bucket-shelf and arms and the" rear legs of the ladder.

Where corresponding members are shown in the drawlugs, and referred to in the specification, corresponding numerals are used to facilitate comparison therebetween.

The present invention, broadly speaking, relates to a stepladder that comprises a pair of front support legs,-a top support member operatively engaged with the front support legs, a pair of back support legs pivotally securedto the unit of the top support member and front support legs, a bucket-shelf pivotally carried by the back support legs spaced from the top thereof and including support arms operatively associated with the front support legs when the bucket-shelf is operatively positioned, spreader means pivotally engaging and extending between the front and back support legs below the bucket shelf, extension legs individually telescopically engaging each of the support legs, lock means carried on each of the support legs for operative positions engaging the extension legs to hold them in given positions, and control means slidably carried by the support legs and engaging the lock means and the bucket shelfv to move the lock means to operative posicured thereto and extends therebetween at the upper ends of such front legs. Any conventional type of rungs or supports 5 are secured to and extend between the front legs 2 and 3 in desired vertically spaced relation for load support use. A pair of rear legs 6 and 7 are PIV- otally secured to the unit formed from the front legs 2 and 3 and the top support 4 in a conventional manner. Other substantially conventional members in the ladder include pairs of

brace bars

8, 8 and 9, 9 that are pivotally secured to each other and to the front legs 2-and 3 and rear legs 6 and 7, respectively, for retaining the front legs 2 and 3 and rear legs 6 and 7 in operative positions, when desired. Also, a bucket-shelf or support 10 is provided in the stepladder and it is operatively secured to the stepladder by means of a pair of support arms 11 secured to and extending from the rear legs 6 and 7 with which the bucket-shelf 10 is pivotally engaged so that such support arms 11 can engage a support rung or other members associated with the front legs of the stepladder to hold the bucket-shelf operatively positioned.

At the lower end of each of the legs of the stepladder 1, an extension leg 12 is telescopically carried thereby to provide adjustable support members in the ladder. Preferably these front and rear legs of the stepladder are all made from a lightweight metal member, such as aluminum, and they usually are of channel shape in section. The extension legs 12 can likewise be formed of a lightweight, channel-shaped member and they will readily mo've outwardly of the front and rear legs by gravitational action but can be positioned completely with the primary legs when retracted. Each of the extension legs 12 has a rack, or other suitable gear or ratchet means 13 provided therein, and secured to one portion thereof. These racks 13 extend longitudinally of the extension legs 12 at least the desired distance of movement of the extension legs in their carrier or support legs in the ladder.

A further feature of the invention is that individual lock means, indicated as a whole by the numeral 14, are provided on each of the front legs 2 and 3 and rear legs 6 and 7 adjacent the bottom thereof and on the inner surface of such legs, preferably. The lock means 14 each include a support, or positioning plate 15, usually riveted or otherwise permanently secured to each of the front and rear legs, and with each such support plate 15 having a stop or edge flange 16 formed thereon. The actual lock member provided in each of the lock means 14 includes a lock plate or pawl 17. The lock plate 17 can be of substantially U-shape in section and is pivotally positioned on the support plate 15, as by means of a rivet, or pin 18, or equivalent member. A coil spring 19 is carried by each of the rivets 18 and has one end thereof bearing on the edge flange 16 or other part of the support plate 15, whereas the other end of the coil spring 19 resiliently bears on the lock plate 17 to urge it to a position, as shown in FIG. 6, for engaging the rack 13 to prevent the extension legs from moving or falling out of the ladder leg under no load conditions. Hence when no other forces are exerted on the lock plate, it is in the position shown in FIG. 6 but other means are present to move the lock plate to the positions shown in FIGS. 7 and 8. To this end, a control rod 20 is carried by each of the legs of the step ladder 1, and it has an end flange or finger 21 thereon received in a recess or aperture 22 in the lock plate 17 so that the control rod 20 can move the lock plate 17 to a neutral position, FIG. 7, or else to an operative, or load-carrying position as shown in FIGS. 8 and 9. The lock plate 17 prevents inward movement of the rack 13 with relation to the stepladder support legs when the lower end of the lock plate is swung out and the stepladder is ready for load. It is an important feature of the invention that the control rods 20' are slidably carried by the support legs of the stepladder and extend vertically thereof in each leg to the bucket-shelf in the stepladder, which shelf and associated means controls the vertical position of the control rods 20* in the individual support legs for regulating action of the lock means in the stepladder assembly. Each of these rods 20 has a support shoulder 23 provided thereon and extending substantially horizontally in the stepladder 1 immediately adjacent and above the pivotal connections of the brace bars 8 and -9 to the support legs. The control rods each also have a hook-shaped upper end 24 thereon positioned substantially in horizontal alignment with the bucket shelf 10 when operatively positioned.

FIGS. 3 and 4 best show that the brace bars 8 engaging the front legs 2 and 3 each have a lug or flange plate 25 secured thereto which normally extends upwardly from the brace bar to engage the shoulder 23 on an associated control rod when the control rod is released by other control means provided therefor, and the control rods thus are permitted to be pulled downwardly in the stepladder by gravity. Similar legs or controls 26 are provided on the brace bars 9 adjacent their pivotal connection with the rear legs 6 and 7 so that such lugs 26 will normally extend vertically upwardly of the rear legs and engage the shoulders on the associated control rods to permit them to have only limited downward movement in the stepladder when the brace bars are operatively positioned. In such instances, when the

brace bars

8 and 9 are operatively positioned, the control rods in the support legs will drop down upon and rest upon the

lugs

25 and 26 until the brace bars are moved to collapsed or inoperative posi tions, as shown in FIG. 5. With the pivotal movement of the

brace bars

8 and 9 to inoperative or collapsed positions, these

lugs

25 and 26 are gradually swung over to substantially horizontal positions (FIG. 5) at which time the control rods 20 though the support shoulders 23 thereon still engage the

lugs

25 and 26 gradually permit the lock plates 17 to move from the inoperative positions, as shown in FIG. 7, to a limited locking position. Only limited downward movement of the control rods 20 is permitted as long as the

lugs

25 and 26 extend upwardly of the pivot points for the

brace bars

8 and 9. When fully collapsed, the brace bars and other operative means for the control rods 20 permit slight additional downward movement, at which time the control rods and lock plates can move from their inoperative positions, as shown in FIG. 7, over to their limited force locking positions for the control rods. When the control rods 20 are released, the lock plates 17 are urged into locking engagement with the racks 13 by gravity and by the springs 19 to prevent the extension legs 12 from freely falling out of or moving with relation to the legs of the stepladder in which they are telescopically received. As this is more or less of a reverse locking engagement of the lock plates with the racks 13, it will not carry the maximum loads of the ladder but will serve to facilitate moving and storing the ladder when the brace bars 8 and 9 are inoperative.

Further control action on the rods 20 and associated means is effected through the bucket shelf 10 and support arms 11. Thus FIGS. 3, 4, 5 and 10 of the drawings best show that a substantially Z-sha-ped lock section 27a, formed on each end of a rod or wire 27, is pivotally secured to each of the front legs 2 and 3 on the inner surface thereof, with the wire 27 extending between such legs 2 and 3. An offset end 28, provided on each of the Z-shaped portions 27a of the lock Wire 27 extends through and is journalled in one of the front legs 2 and 3 of the stepladder. The lock wire 27 preferably is immediately below one of the rungs 5 to protect such wire 27 and the end portions thereof. Each of the end portions 27a preferably has a pin 30, FIG. 10, secured thereto and extending laterally therefrom for engaging the hook-shaped upper end 24 of the associated control rod 20. The parts are associated so' that vertical swinging movement of the lock wire 27 by the shelf arms 11 will cause the lock wire and end portions thereof to be moved upwardly vertically in the stepladder 1 to lift or raise each of the control rods 20 a suitable distance to cause the lock plates 17 to be moved from their neutral, or secondary locking positions thereof, over to the locked load carrying positions therefor, as shown in FIG. 9. Such action by the lock plates 17 will set or lock the extension legs 12 in their then given positions and adapt the stepladder 1 for load support action. The extension legs 12 will previously have moved by gravity to any required relationship to the front and rear legs of the stepladder for positioning the stepladder 1 generally in a horizontal position, even though an irregular surface supports the different legs of the ladder. The control rods 20 slidably carried by the rear legs 6 and 7 of the stepladder 1 are engaged and lifted by a cross bar or red 31 that is secured to and extends between the support arins 11 of the bucket-shelf adjacent but forwardly of and usually above the means pivotally securing the bucket-shelf 10 to the rear legs 6 and 7. Hence, such cross bar 31, when the support shelf 10 is moved to operative position, will provide a short and rapid vertical upward lift to the control rods 20 and to the associated lock plates 17 to swing them to operative positions and secure the extension legs on the rear legs in given positions.

It will be realized that any suitable type of lock means can be associated with the front and

rear legs

2 and 3 and 6 and 7, respectively, of the stepladder 1 for retaining the extension legs 12 in given positions. Such lock means in the embodiment of the invention illustrated in the accompanying drawings provides a relatively uncomplicated control by which the locks can be set in either released positions or locked positions for either load carrying action or for convenient transport or storage of the stepladder 1.

It should be noted that the stepladder 1 can be set in substantially fully operative positioned and with the leg braces 8 and 9 in operative positions, but with thebucket support shelf 10 still being in its raised or elevated position, and at such time the extension legs 12 are free for vertical movement with relation to their carrier legs in the ladder. Hence after the extension legs automatically move by gravity to properly adjusted positions, the extension legs can be locked in place by moving the bucket support shelf to operative position, and the ladder will be set for load support action.

In some instances, it might be desirable to omit the control action on the means 20 by lugs, or the like, associated with the spreader means. Likewise, it is possible to control the final or load lock action on the extension legs, or members solely by the spreader means and members operatively associated therewith. In such cases where only two fixed positions would be provided for the control rods 20, one position could be a fully released position and one position could be a locked, load-carrying position. Or the control rods 20 might have a locked load-carrying position and a secondary locking position for holding the extension legs in given positions for storage or transit "action but with a neutral, release position being obtained when the actuating control (spreader means or bucket support shelf) is intermediate its operative and release positions.

FIG. 6 best shows that a slot 32 is formed in the lock plate 17 for receiving the control rod 20 in one position of the lock plate so that a compact, direct connection of the members can be made.

It will be realized that the extension members 12 can slidably engage the ladder legs in any desired manner and that the extension members are individually movable or adjustable, when released. In some cases, only a pair of front or rear extension members 12 may be used, or only one such member may be useful for certain support actions.

Suitable guides, not shown, may be provided for the control rods 20, and any suitable stops limit movement of the members 12 to prevent their disengagement from the support legs.

The stepladder of the invention is believed to be made from a relatively few parts when considering the automatic locking and release action obtained in the positioning of all four of the extension legs 12. The control means in the ladder will function effectively over a long service life.

While one complete embodiment of the invention has been disclosed herein, it will be appreciated that modification of this particular embodiment of the invention may be resorted to without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A stepladder comprising a pair of front support legs, a top support member secured to and extending between said front support legs at the top thereof, a pair of back support legs pivotally secured to said top support memher, a bucket-shelf pivotally carried by said back support legs spaced from the top thereof and including support arms operatively associated with said front support legs when said bucket-shelf is operatively positioned, spreader means pivotally engaging and extending between said front and back support legs below said bucket-shelf, extension legs telescopically engaging each of said support legs, lock means on each of said' support legs adapted to have operative positions engaging said extension legs to hold them in their present positions, and control means slidably carried by said support legs and engaging said lock means and said bucket-shelf to move said lock means to operative position to lock said extension legs in place when said bucket-shelf is operatively positioned.

2. A step'ladder as in claim 1 where said control means have shoulder means thereon to operatively engage part of said spreader means, said lock means being urged to a neutral position to release said extension members when said control means engage said spreader means and said spreader means are operatively positioned.

3. A stepladder as in claim 1 where said control means have hook-shaped upper ends and said bucket-shelf has means associated therewith to engage said upper ends and move said lock means to a locked position for said extension members when said bucket-shelf is operatively positioned.

4. A stepladder comprising a pair of front support legs, a top support member secured toand extending between said front support legs at the top thereof, a pair of back support legs operatively secured to said top support member and front legs, a bucket-shelf pivotally carried by said back support legs spaced from the topthereof and including support arms operatively associated withsaid front support legs when said bucket-shelf is operatively positioned, spreader means pivotally engaging and extending between said front and back support legs below said bucket-shelf, extension legs slidably engaging each of said support legs, lock means carried by each of said support legs and adapted to have operative positions engaging said extension legs to hold them in their present positions, control means carried by said support legs and engaging said lock means and said bucket-shelf to movesaid lock means to operative position to lock said extension legs in place when said bucket-shelf is operatively positioned, and means operatively associated with said spreader means to engage said control means and move said lock means to released positions when said spreader means is operatively positioned, said control means being movable longitudinally of said support legs to control the positions of said lock means.

5. A stepladder comprising a pair of front support legs, a top support member secured to and extending between said front support legs at the top thereof, a pair of back support legs operatively secured to said top support memher, a bucket-shelf pivotally carried by said back support legs spaced from the top thereof and including support arms operatively associated with said front support legs when said bucket-shelf is operatively positioned, spreader means pivotally engaging and extending between said front and back support legs below said bucket-shelf, extension legs slidab'ly engaging each of said support legs, lock means on each of said support legs adapted to have.

operative positions engaging said extension legs to hold them in their present positions, and control means carried by said support legs and extending vertically thereof, said control means engaging said lock means and operatively engaging said spreader means and said bucket-shelf to move said lock means to operative position to lock said extension legs in place when said bucket-shelf is operatively positioned, and to move said lock means to a release position when only said spreader means is operatively positioned.

6. In a stepladder having pairs of front and rear support legs, spreader means, and a bucket-shelf, the improvement comprising extension members telescopically carried by and freely movable on each of said legs, spring actuated locking means pivotal ly carried by each of said legs adjacent said extension members and having an operative position engaging an associated one of said extension members to lock it in a given and load carrying position, and control means carried by said legs and extending between said locking means and bucket-shelf to secure said locking means in operative positions when said bucket-self is operatively positioned, said locking means being constructed and arranged to move to a locked position to engage said legs and hold them against downward sliding movement when the stepladder is collapsed.

7. In a stepladder having pairs of front and rear support legs, spreader means, and a bucket-shelf having lugs thereon, the improvement comprising extension members slidably carried by each of said legs and adapted to extend therefrom, locking means pivotally carried by each of said legs adjacent said extension members and having an operative position engaging an associated one of said extension members to lock it in a load carrying position, and control means slida'bly carried by said legs and extending between said locking means and bucket-shelf to secure said locking means in operative positions when said bucket-shelf is operatively positioned, said control means having sections thereon operatively engageable by said lugs on said spreader means when said bucket-shelf is inoperatively positioned and said spreader means is operatively positioned to hold said locking means to a release position.

8. A stepladder as in claim 7 wherein said locking means include a locking plate and said extension mem bers have rack gear means thereon, said control means being movable downwardly by gravity on release thereof by said bucket-shelf and by said spreader means, a spring being operatively engaged with said locking plate to bring it into retaining engagement with said rack gear means to hold said extension members against movement outwardly of said legs when said control means are released.

9. In a stepladder having pairs of front and rear support legs, spreader means, and a bucket shelf, the improvement comprising extension members slidably carried by each of said legs, locking means having a pair of locking edges thereon pivotally carried by each of said legs adjacent said extension members and having an operative position engaging one of said locking edges with an associated one of said extension members to lock it in a load carrying position, spring means engaging said locking means, and control means carried by said legs and extending between said locking means and bucket-shelf to secure said locking means in operative positions when said bucket-shelf is operatively positioned, said control means being movable by gravity to urge said locking means towards a second locking engagement position with said extension members when released by said bucketshelf, said spring means also urging said locking means to said second locking position to retain said second locking edge engaging said extension members and hold them in given positions when the stepladder is collapsed.

10. A stepladder comprising a pair of front support legs, a top support secured to and extending between said front support legs at the top thereof, a pair of back support legs pivotal'ly secured to said top support, a bucketshelf member pivotally carried by said back support legs spaced from the top thereof and including support arms operatively associated with said front support legs when said bucket-shelf member is operatively positioned, a spreader member pivotally engaging and extending between said front and back support legs below said bucketshelf member, extension legs telescopically engaging each of said support legs, lock means on each of said support legs adapted to have operative positions engaging said extension legs to hold them in their present positions, and control means slidably carried by said support legs and engaging said lock means and one of said members to move said lock means to locked load carrying engagement with said extension legs when said one member is operatively positioned.

11. In a stepladder having pairs of front and rear support legs, spreader means, and a bucket-shelf, the improvement comprising an extension member slidably carried by at least one of said legs, a locking means pivotally carried by said one leg adjacent said extension member and having an operative position engaging said extension member to lock it in a given load carrying position, said locking means having a release position, and control means slidably carried by said one leg and extending between said locking means and bucket-shelf to secure said locking means in operative positions when said bucketshelf is operatively positioned, said control means including means thereon operatively engaging said spreader means when said spreader means is operatively positioned and said bucket-shelf is inoperatively positioned to retain said locking means in a release position.

References Cited in the file of this patent UNITED STATES PATENTS 1,229,218 Bryant June 12, 1917 FOREIGN PATENTS 146,020 Australia Apr. 8, 1952 1,103,091 France May 8, 1955