US2470053A - Convertible stepladder - Google Patents

Description

' 2 Sheets-sheaf 2 R. R. SALISBURY CONVERTIBLE STEPLADDER' I l I l I L l May 10, 1949.

Fii d July 8, 1946 Patented May 10, 1949 UNIT STATES PATE11 1?!" 1 Claim.

The invention relates: to. ladders and more particularly to, the-type ofladder which. is adapted to be convertible from a step ladder to an extension ladder.

An object of: this. invention is to provide a convertible step ancli extensionladder which may readily be converted from a step ladder into an extension ladder by partially rotating the back of the stepladder upwardly andengaging it with the front ladder to.provide an upward extension thereof.

Another object ofthis invention is to. provide an improved convertible step and extension lad:- der which includes at front step ladder section and a runged rear supportsection. pivotally. connected at their. upper end whereby the rearsection may be rotated to provide an extension of the front ladder section and: an improved wedge shaped interlocking joint or connection carried partially by the frontsection and partly by the rear sectionv engageable in the extended position of the ladder.

Still another object of this invention is to provide an improved locking means for connecting the extending-ladder sections together wherein the locking means consists of aflanged wedge shaped member having: alocking wedgefixed on one ladder section and. av cooperating wedge shaped-member carried-'bythe other ladder section and a resilient or spring pressed keeper on the latter member engageable with the locking wedge on the first member, for holding the adjacent ladder sections in extended position whereby the resilient keeper may be readily disengaged by an operator for folding the ladder sections to a step ladder position.

With the above and other objects in view, my invent-ionconsists in the arrangement, combination and details ofconstruction disclosed in the drawingsand specification; and then more particularly pointedout in theappended claim.

In the drawings,

Figure 1 is a sideelevation of-a convertible step and extension ladder constructed according to an embodiment, of-myinvention,

Figure 2 is a rear elevation of the ladder,

Figure 3, is a fragmentary rear elevation-of the ladder in extended position,

Figure 4 is a horizontal section taken on the line 4-4 of Figure 3,

Figure 5 is a detail side elevation of one clamping member separate from the ladder,

Figure 6 is a detail side elevation of the other clamping member separate from the ladder,

Figure '7 is a perspective fragmentary viewof an extension ladder attachment.

In the drawings the'numeral: ltfltdesignates generally a convertible step.- and; extension ladder constructed accordingt an. embodiment of. this invention. The ladder consists of a. front ladd t n. N and a rear ladder a d: supp rt n member l2 hingedlyconnected together near their upper ends. The front ladder sect-ion. consistS, of a pair of; elongated sideor supporting m m rs L andrun s 1 =QDO. iI1g: m mbersv l4 and run s l5 pported tberebetween. The, side pp n members; l4; are maint ined. in an pwardly convergent relation; whereby the; rungs l5 at the lower end, thereof. aresl n er than the up,- per rungs, the rungs, being successively shorter along the length of; this lower: ladder section H.

The rungs l5: are. securedto thesidemembers M by en agingL in. transrerse grooves: ornotches l6 therein and. are strengthened: by. rods. ll, con.- nected to the side membersslfiionieachend there-.- of directly. below v each. runs. or step, It: and; support the step l5. by engaging below a. block 18 on the center of. each. step. I5 below; the longitudinal median of: thestep l5;

Spaced. downwardly: from; theupper. end of the ladder section ll on each member Ht approximately below the'highest step' t-i'r, there is secured ahingemember- I9; Thehingemember- [9 comprises a clamping strap 20 which encircles the member l4. andis secured? thereon by rivets. 2! or other suitable fasteningtmeans; Airearwardly extending lug or apertured can 22 is fixed to'or formed on the straplfl' onthe rearward side thereof and is adapted toprovide a section of hinge barrel to which the rear section l2 may be hingedly attached.-

The rear-ladder orsupporting member ['2' is formed of a pair of parallel side supporting members 24 which support a series of'rungs 25thereon. The-rungs 25' areformed ofroundecl sections or rods, the ends of" which maybe imbedded in sockets or openings 26" in the side members 24. The rungs 25 are or equal length substantially equal to the" averagewidthof-therungs l5 of the front ladder section ,whereby the'upper end of the rear section I2 is wider than the upper end of thefront-sectionll.

Hinge members 21 are carried by the side members 24 at their upper ends and are formed of a clamping strap 28 which encircles the member 24 and is fastened thereto by rivets 29 or other suitable fastening means. A forwardly extending apertured lug or ear 3|! is fixed to or formed on to the strap 28 and a hinge pin 3| extends through the ears 22 and 30 for hingedly connecting the ladder members II and I2 together. A wing nut 32 secures the rod or pin 3| in position and may be tightened or loosened by an operator for adjusting the friction on the hinge members l9 and 21.

In the lower folded or step ladder position, as shown in Figure 1, the rear section I2 provides a support for the front ladder section H and is held against sliding outwardly by a chain 34 fixed at one end to the section II as by a link 35 and is detachably connected to the member l2 by a spring pressed clamp 36 secured to the chain 34 engaging in eye bolts 31 fixed in the side members 24.

For latching the front and rear ladder section II and I2 together in the extended or aligned position thereof, I have provided a pair of interengaging locking members 38 and 39 carried by the front and rear sections l i and i2 respectively.

The locking member 38, fixed on the side members I4 of the front ladder section H is formed of a flat strip of metal having a pair of oppositely disposed rearwardly diverging flanges it and an outwardly extending ear ll on each end thereof. The ears 4| are adapted to be bent around the edges of the member M with the inwardly bent flanges 4i] on the outside of the members l l. Between the flanges 30 there is secured a rearwardly and outwardly extending wedge shaped keeper 42 fixed to the member 38 by rivets it or other suitable fastening means.

The locking member 39, fixed on the members 24 of the rear ladder I2, is adapted to engage in and lock onto the locking member 38. The locking member 39 is formed of a flat strip of metal having a pair of oppositely disposed rearwardly diverging inwardly inclined flanges 46. A pair of ears 41 are fixed on opposite ends of the members 39 for attaching the member 39 to the side ladder members 24. Between the flanges 46 there is fixed a flat elongated hook member 45 fixed at its forward end to the member 39 by a rivet 48 or other suitable attaching means, and is adapted to be engaged over the keeper 32. The members 39 are fixed on the inside of the ladder side members 2d in such a manner as to engage in and become latched in the members 38 fixed on the outside of the front ladder side members M.

In the use and operation of this ladder It to convert the ladder from a step ladder as shown in Figures 1 and 2, the hook 36 is disengaged from the eye 37 and the rear ladder I2 is pivoted about the hinge bolt 3| until the latch member .39 is engaged in latch member 33 as seen in Figure 3 and the hook :35 engages with the wedge lock member 42 securing the front and rear ladder sections H and 12 together. To disengage the ladders II and [2 it is necessary only for an operator to move the keeper it out of engagement with the wedge 42 with his fingers and rock the rear member l2 rearwardly and downwardly to its original position where the clamp 36 may again be engaged with the eye 3'! in the step ladder position. 7 i

A basket may be provided to be supported on the ladder In. This basket 50 is formed of a wire body 5| having forwardly extending handles or rods 52. The rods 52 extend forwardly over the top rung of the ladder, are then reverted forwardly and downwardly where they are bent outwardly near their terminals in a right angularly bent section 53 engageable with the side members, as M, for securing the basket 5t? thereon.

In Figure '7 there is shown an attached extension ladder section 60 which may be used to lengthen the extended step ladder I0. As the sides 24 of the rear and upper section 12 are parallel, an extension ladder 60 may be secured to the upper extended end thereof. The extension is provided at its lower with a pair of oppositely disposed U-shaped channel sections 6| fixed to the side members 62 of the ladder 60 by bolts 5% and which encompass the side members 62 and extend downwardly past the ends of the members 62 to encompass the side members 24 of the ladder section 12. The ladder extension fill may be attached when the ladder I0 is in its extended position.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claim.

What I claim is:

In a combination step and extension ladder having hingedly connected front and rear section a releasable locking means for locking the front and rear ladder sections in aligned position, said locking means comprising locking members carried by one of said ladder sections, rearwardly diverging flanges on said locking member, a wedge-shaped keeper fixed to said member between said flanges and spaced inwardly from the ends thereof, locking members carried by the other of said ladder sections, rearwardly diverging flanges on said latter members slidably engaging said first mentioned flanges and spacing said latter members from said first mentioned members, a spring-pressed hook on said latter members between the flanges and ends thereof engageable with said keeper for locking said ladder sections together, and a hook releasing member carried by said hook extending beyond one end of said locking members.

RAYMOND R. SALISBURY.

CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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