US3165170A

US3165170A - Ladder extension

Info

Publication number: US3165170A
Application number: US307547A
Authority: US
Inventors: Jack C Blaney
Original assignee: JACK Inc A
Current assignee: A-JACK Inc; JACK Inc A
Priority date: 1963-09-09
Filing date: 1963-09-09
Publication date: 1965-01-12
Anticipated expiration: 1982-01-12

Description

Jan. 12, 1965 .1. c. BLANEY LADDER EXTENSION Filed Sept. 9, 1963 INVENTOR.

JACK c BLANEY A TTORNEYS' United States Patent 3,165,170 LADDER EXTENSION Jack C. Blarney, Pittsburgh, Pa., assignor to A-Jack, Inc., Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 9, 1963, Ser. No. 397,547 4 Claims. (Cl. 182203) This invention relates to an attachment for ladders by which the effective length of the side rails of the ladder may be selectively adjusted to accommodate uneven surfaces and permit the ladder rails to assume a substantially vertical position in which the rungs are disposed in a horizontal plane.

An object of this invention is to provide an improved ladder attachment that can be quickly and easily attached to and removed from a ladder, and which when attached to the ladder permits the ladder to assume a position in which the rungs of the ladder are horizontally disposed regardless of the uneveness of the surface on which the ladder is supported.

A further object is to provide an improved ladder attachment that is simple and emcient in construction, economical to produce, and reliable in operation.

The foregoing and other objects are achieved by the provision of a hollow sleeve member of substantially rectangular cross-section which is preferably of extruded alumi .um in which is telescopically mounted an extruded aluminum extension member; Mounted on one wall of the hollow sleeve is a spring arm which carries at its free end a latching member. The latching member is engageable through an opening in the sleeve with a series of openings in the extension leg so that the leg may be selectively positioned relative to the sleeve. A pair of vertically spaced brackets are secured to the sleeve member and are grooved to receive the rungs of a ladder and thereby support the ladder through the rung-s.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing in which;

FIG. 1 is a perspective view of a ladder having a ladder jack attachment embodying the present invention secured thereto;

FIG. 2 is a perspective view of the ladder jack of FIG. 1;

FIG. 3 is a side view of the ladder jack of FIG. 1;

FIG. 4 is a detailed sectional view taken on lines 4-4 of FIG. 3 and FIG. 5 is a detailed sectional view taken on lines 55 of FIG. 1.

Identified generally by reference numeral is a ladder having

side rails

12 and 14 joined together by a series of rungs 16. As illustrated in FIG. 1, the lower end of the ladder rests upon steps so that one leg is seated against one of the steps and the other leg projects above the surface of the next lower step. Secured to rail 12 is a ladder jack identified generally by reference numeral 18 embodying the invention by which the effective length of side rail 12 can be selectively extended so that both side rails are supported on the steps in such .a manner that the ladder is vertically oriented.

With reference to FIG. 2, the ladder jack 18 includes a hollow sleeve 20 of rectangular cross-section. Sleeve 20 preferably is an aluminum extrusion, and is formed with

side walls

22 and 26 joined together by

end walls

24 and 28.

Secured to end wall 28 is a pair of vertically spaced

brackets

30 and 32. Bracket 32 is secured to end wall 28 adjacent the upper end of sleeve 20, and bracket 30 is disposed beneath bracket 32 intermediate the ends of sleeve 20. Bracket 36 includes an arm member 34 extending at right angles from the end of a leg 38, leg 38 in turn being secured to sleeve 20 by rivets 40. It should be understood that leg member 38 and wall 28 can be provided with matched threaded openings to receive threaded fasteners instead of rivets to permit the brackets to be selectively removed and replaced. Moreover, a slotted opening may be provided in leg 38 to receive threaded fasteners to permit adjustment of the bracket on sleeve 20. Formed in bracket arm 34 is a groove 36, having straight, substantially parallel side edges joined by a lower edge which is semi-circular for receiving and supporting the rungs 16 of the ladder. The vertical spacing of

brackets

30 and 32 is such that when a rung 16 is received in groove 36 of bracket 30, the next higher rung 16 will be accommodated in the corresponding groove in bracket 32. In FIG. 2, tab 34a forming one side edge of groove 36 on bracket 30 extends about one-half the length of the groove, i.e. one side edge of the groove may be cut away as shown so that when the corresponding groove in bracket 32 is partially engaged with an upper rung, the entire assembly can be swung in a clockwise direction as shown in FIG. 1 until the lower rung 16 passes over the top of tab 34a to .be received in groove 36. Bracket 32 is otherwise identical to bracket 30, and will therefore not be described in detail.

As shown in FIG. 5, when groove 36 is engaged with rung 16, side rail 12 is nested between bracket arm 34 and wall 22 of sleeve 20. Slidably received in sleeve 2-13 is an extension member 42 in the form of an aluminum extrusion having a base 44 with a pair of legs 46 extending from the base near its ends. Legs 46 are preferably turned outwardly at their ends and base 44 extends slightly beyond its junction with legs 46 to provide added torsional strength as well as bending strength in both directions about the vertical axis. Formed in base 44 of extension member 42 is a series of openings 48. Mounted on sleeve 20 is a latching assembly which includes a spring arm member 50 secured at its lower end to the lower end of wall 26 by rivets 52. Mounted adjacent the free end of spring arm St) is a latching plunger 54 which projects through an opening 48a in wall 26 when spring arm 50 is permitted to assume its unstressed position shown in FIG. 4. Plunger 54 is selectively engageable with any one of openings 48 in extension member 42. Consequently, by pulling spring arm member 50 outwardly from wall 26 (in a clockwise direction as viewed in FIG. 4) by means of tab 50a formed at the free end of spring arm 50, plunger 54 can be withdrawn from openings 48 permitting extension member 42 to be partially or fully extended from sleeve 21 or to be completely telescoped within the sleeve. When member 42 has reached its desired position, plunger 54 is permitted to assume the position shown in FIG. 4 in which it is received within the opening 48 that registers with the associated opening 48a in wall 26.

When it is desired to secure the assembly to one of the side rails of the ladder while the ladder is being transported from place to place, upper and

lower slots

56 and 58 are formed in wall 22 to cooperate with conventional fasteners to detachably mount the, assembly on side rail 12. For example, in FIG. 5, bolts can be provided which extend through side rail 12 and when

slots

56 and 58 register with the bolts, suitable nuts or threaded fasteners can be mounted on the bolts to secure the leg member to the side rails of the ladder. Conventional shoes, as shown in phantom lines in FIG. '3, can be pivotally attached to member 42 through the lowermost opening 43 of extension member 42 to accommodate Varying angles of support.

From the foregoing description, it is apparent that a rugged, efiicient ladder jack has been provided which incorporates a minimum number of parts and by its very altar? simplicity insures reliable operation. The ladder jack embodying the invention can be attached to or removed from the ladder with ease and its operation requires a minimum amount of effort to accomplish the desired results. The configuration of the extension member 42 which is received in the hollow sleeve or track member 29 provides more than adequate strength and yet requires a minimal amount of material. All of the parts are preferably made of aluminum to give :a minimum amount of weight'without sacrificing strength.

While a specific embodiment of the invention has been illustrated and described, it should be understood that the'invention is not limited to the exact construction shown but that various alterations in the design and arrangement of parts can be accomplished by those skilled in the art without departing from the scope and spirit or the invention.

What is claimed is:

1. An attachment for ladders comprising,

a hollow sleeve member of substantially rectangular cross-section having a pair of side Walls joined by end Walls,

an opening formed in one of said side walls,

a resilient arm member secured at one end to said one side wall,

a latching plunger mounted on the free end of said resilient arm member for movement into and out of the opening in said one side wall and projecting into said opening when said arm member is in its unstressed position,

an extension member of LJ-shape in cross section slidably received in said sleeve member for movement between selected positions in which it projects from said sleeve member and a retracted posit-ion in which it is wholly received Within the sleeve member, said extension member having spaced flanges connected by an integral web,

a series of openings formed in the web of the extension member along the longitudinal axis thereof,

each opening of said series being selectively engageable by said latching plunger when said resilient arm member is in said unstressed positionlto maintain said extension member in one of said selected positions,

and a pair of vertically spaced brackets mounted on said sleeve member having upwardly-facing notches adapted to engage a selected pair of ladder rungs for supporting one side rail of the ladder on said extension member.

2. The construction defined in claim 1 of said brackets includes a leg member secured to one of said end walls,

an arm member projecting at a right angle from the end of said leg member in parallel opposed relaonship to the other of said side walls to define a 35 for receiving a side rail of a ladder.

and the upwardly-facing notches being formed in said arm member and having straight parallel side edges joined by a lower, semi-circular edge.

3. A ladder extension comprising a ladder leg, a hollow sleeve member rectangular in cross sectional shape and having a wall disposed against the outer face of the ladder leg, a pair of vertically-spaced L-shaped brackets mounted on a face of the sleeve member, each bracket having a part extending across the inner face of the ladder leg, said part having an upwardly-extending notch for engagement with a ladder rung, an extension member oi substantially U-shape slidable within the sleeve member, said extension member consisting of a pair of side flanges integrally connected with a Web, said web being provided with a longitudinally-extending row of holes, a leaf spring attached to a face of the sleeve member on the outside of said sleeve member, said leaf spring having a plunger attached adjacent to one end, the face of the sleeve member having a hole through which the plunger is projec ed by the bias of the leaf spring and caused to enter any selected one of the holes in the web to thereby position the extension member with a portion of it extending [or a desired distance below the lower end of the sleeve member.

4. A ladder extension as provided for in claim 3, wherein the face of the sleeve member that is disposed against the outer face of the ladder leg is provided at its opposite ends with slots, one of said slots opening up wardly and the other opening downwardly, the notch of one of the L-shaped brackets being horizontally aligned with one of the slots, and the second L-shaped bracket being located at a point above the second slot.

invv 2n Reierences tilted by the Examiner UNITED STATES PATENTS 294,199 2/84 Cloves 18 -204 2,308,832 1/43 Roney l82-l78 2,498,944 2/50 Dyer l82l21 2,783,928 3/57 Cox 182-403 2,936,849 5/60 Larson 182-20d HARRISON R. MOSELEY, Primary Exalm'ner.

Claims

1. AN ATTACHMENT FOR LADDERS COMPRISING, A HOLLOW SLEEVE MEMBER OF SUBSTANTIALLY RECTANGULAR CROSS-SECTION HAVING A PAIR OF SIDE WALLS JOINED BY END WALLS, AN OPENING FORMED IN ONE OF SIDE WALLS, A RESILIENT ARM MEMBER SECURED AT ONE END TO SAID ONE SIDE WALL, A LATCHING PLUNGER MOUNTED ON THE FREE END OF SAID RESILIENT ARM MEMBER FOR MOVEMENT INTO AND OUT OF THE OPENING IN SAID ONE SIDE WALL AND PROJECTING INTO SAID OPENING WHEN SAID ARM MEMBER IS IN ITS UNSTRESSED POSITION, AN EXTENSION MEMBER OF U-SHAPE IN CROSS SECTION SLIDABLY RECEIVED IN SAID SLEEVE MEMBER FOR MOVEMENT BETWEEN SELECTED POSITIONS IN WHICH IT PROJECTS FROM SAID SLEEVE MEMBER AND A RETRACTED POSITION IN WHICH IT IS WHOLLY RECEIVED WITHIN THE SLEEVE MEMBER, SAID EXTENSION MEMBER HAVING SPACED FLANGES CONNECTED BY AN INTEGRAL WEB, A SERIES OF OPENINGS FORMED IN THE WEB OF THE EXTENSION MEMBER ALONG THE LONGITUDINAL AXIS THEREOF, EACH OPENING OF SAID SERIES BEING SELECTIVELY ENGAGEABLE BY SAID LATCHING PLUNGER WHEN SAID RESILIENT ARM MEMBER IS IN SAID UNSTRESSED POSITION TO MAINTAIN SAID EXTENSION MEMBER IN ONE OF SAID SELECTED POSITIONS, AND A PAIR OF VERTICALLY SPACED BRACKETS MOUNTED ON SAID SLEEVE MEMBER HAVING UPWARDLY-FACING NOTCHES ADAPTED TO ENGAGE A SELECTED PAIR OF LADDER RUNGS FOR SUPPORTING ONE SIDE RAIL OF THE LADDER ON SAID EXTENSION MEMBER.