US1912509A - Ladder - Google Patents

Description

June 6, 1933. H -E BALLARD 1,912,509

LADDER Filed Aug. l5, 1931 v 2 Sheets-Sheet l Jime 6, 1933. H. E BALLARD 1,912,509

LADDER Filed Aug. 15, 1951 V.2 sheets-*sheet 2 l immuni Q um Patented June 6, 1933 UNITED STATES PATENT OFFICE HARRY E. BALLARD, or HOLYoKE, MASSACHUSETTS, AssIGNon Tov THE ooBURN TROLLEY TRACK MANUFAcTUnING COMPANY, or HoLYoKE, MASSACHUSETTS, A

CORPORATION OF`MASSACHUSETTS LADDER Application led August 13, 1981.

of the invention is to provide simple means whereby the ladder will be normally in position to travel along its defined path but will be automatically held stationary when an attendant mounts thereon. A further object of the invention is to provide means whereby a person standing on the ladder may dispose the same for travel Without alighting therefrom. These stated objects and other objects which will appear incidentally in the course of the following description are attained in such a mechanism as is illustrated in the accompanying drawings, and the invention resides in certain novel features which will be particularly defined in the appended claims.

In the drawings, Figure 1 is a front elevation, partly broken away and in section, of one form of the invention, s

Fig. 2 is a. side elevation of the device illustrated in Fig. 2,

Fig. 8 is an enlarged detail sectional elevation more particularly showing the mounting of the roller,

Fig. 4 is an elevation, partly broken away and in section, showing another form of the invention, and

`F ig. 5 is an edge view of the device shown in 4. n

The ladder comprises side bars 1 and steps or rungs 2 mounted between and secured to the side bars in the usual manner. At its upper end the ladder is-provided with devices whereby it may be suspended from a guide rai-l o-r similar member and retained in convenient relation to the shelves of goods.

At its lower end the ladder is equipped with rollers adapted to rest on the floor of the sales or storeroom and effect travel of the ladder from point to point along the shelves. rfhe lower ends of the side bars 1 Serial No. 556,889.

are also equipped with pads or feet 3 of some material which will effect frictional engagement with the Hoor and thereby hold the ladder against travel. In the arrangement shown in Figs. l, 2 and 3, a housing 4 is secured on the outer side of each side bar l at the lower extremity thereof, the housing being open at its bottom, as clearly shown in Figs. 1 and 3. Disposed within each housing is a roller 5, the sides of which are parallel with the sides of the housing and at a right angle to the respective side bar of the ladder. The axle 6 of each roller is disposed. eccentrically in journals 7 which are mounted in bearings or openings provided therefor in the sides of the housing, as shown in Fig. 3, and from each rear journal 7 ex-l tends a `fulcrum pin or shaft' 8.v Secured upon the fulcrum pin or shaft 8 is a hub or sleeve 9 from which risesa crank arm 10 which is oiiset or tilted sufficiently to pass to a point at the rear of the side bars 1, the crank arms 10 at the two sides of the ladder being connected by a rod or link 11 which is pivoted at its ends to the respective crank arms, as shown in Fig. 3 and as will be readily understood. A retractile spring 12 is attached at one end toene of the sidey bars 1 and, at its opposite end, to the connecting rod or bar 11, and tends constantly to hold the ladder raised with the crank arms 10 in such position that the axle 6 will be below the centers of the journals 7 and the fulcrum pin 8 and, consequently, the rollers 5 will support the ladder. The sleeve 9 at one side of the ladder is provided with a second downwardly extending crank arm -13 to which -is pivoted the lower end of an operating bar 14 which extends upwardly and is slidably fitted in guides 15 mounted onV the adjacent side bar of the ladder. l

The spring 12 is adjusted so thatwhen no weight is imposed on the ladder the crank arms 10 will .be swung to the position shown by dotted lines in Fig. 17 the axles of the rollers being below the centers of the journals, and the ladder will be held raised. In this position of the parts, the ladder may obviously be moved from point to point. 1When a person mounts the ladder, his weight will overcome the force of the spring 12 and cause the ladder to move relatively downward so that the feet 3 will be brought into contact. with the floor and travel of the ladder will be thereby prevented. When the ladder is thus moved relatively downward, the crank arms are rocked so that the axles 6 of the several .rollers will be carried relatively upwardlyto points in the horizontal plane of the'V fu'lcrum pin or'shaft 8 or above such plane, as will be understood. If the person upon the ladder desires to have the same shifted to a different point along the shelves, he depresses the rod or handle 14, thereby rocking the crank arms and the fulcrum pin or shaft to their former positions, rs0 that the rollers will be relatively lowered and the ladder will be raised from the floor. The person on the ladder may then easily shift the position of the s ame by pushing against 4the shelves in a well-understood manner.

In the embodiment of the invention shown in Figs. 1, 2 and 8, and just described, the ladder sets parallel-with the shelves and the rollers are also parallel therewith, and both rollers are at the same distance from the shelves. In the arrangement shown in Figs. 4 and 5. the ladderV is disposed at a right angle to the shelves, and one roller is between the ladder and the shelves, while the other roller is at the outer side of thel ladder. Each ,roller16 is mounted in a housing 17 and yis provided with an axle 18 carried eccentrically by journals 19in the same manner as the first-described rollers are mounted. The housings 17 differ from the housings 4, previously described, in being attached to the sides of the ladder at their own sides instead of'at their edges, and the fulcrum pins or i shafts 20 extend through the side bars of the ladder and are engaged in the ends of a rock shaft 21, so that any movement imparted to the rock shaft or to the ful'crum pins or shafts will be transmitted to the other. The rock shaft 21 is provided with a crank arm 22 which normally extends downwardly and rearwardly, as indicated in Fig.- 5, and to this crank arm is attached'the lower end of a spring 23 which has its upper end attached to la step or other fixed part'of the ladder. An operating rod 24 is'pivoted at its lower end to the crank 22 and extends upwardly therefrom at the rear of the ladder, as will be understood. The operation of this form of the invention is the saine in all essential respects as the operation of the firstdescribed form. The spring 23 yieldably holds the ladder raised, the bearings 19 being turned tor such position that they axle 18 is below the 'centers of said bearings and the rollers are in contact with the floor, with the ladder out of contact therewith, as shown. When a person mounts the ladder, his weight overcomes the tension of the spring 23 and effects relative movement of the parts so that the ladder is lowered onto the ioor and held against movement. If, while on the ladder, the person desires to effect travel thereof, he pulls down upon the rod 24 so that the several parts are `returned to the illustrated positions and the ladder raised from the floor in the manner previously described.

The apparatus lis exceedingly simple in the construction and arrangement of its parts and may be readily applied to ladders now in use, as well as ladders in course of construction, and it is highly efficient in operation for the purposes for which it is designed.

I-Iaving thus described the invention, I claim:

1. The Vcombination with aV ladder having feet at its lower end whereby it may be supported in stationary position, of rollers mounted eccentrically at the lower end of the ladder, means for yieldably holding the rollers normally in relatively lowered position whereby to support the ladder out of contact with the floor, said means yielding when a weight is placed upon the ladder to permit the ladder to be relatively lowered, and means on the ladder including rocking connections withthe rollers to be operated by a person on the ladder whereby to raise the ladder.

2. The combination with a ladder, of housings secured to the lower end thereof on the opposite sides of the same, rollers journaled eccentrically in the housings, yieldable means fornormally holding the ladder raised relative to the rollers, said means yielding to the weight of a person on the ladder, an operating rod slidably mounted on the ladder, and connections between said rod and the journals of the rollers whereby said journals may be rocked by a person on the'ladden 3. The combination with a ladder, of housings secured on the sides thereof at the lower end of the same, journals'y mounted in the sides of the housings, axles extending between and carried eccentrically by the journals, ful! crum pins extending rearwardly from the centers of the rear journals, upper crank arms on said fulcrum pins, a rod connecting said crank arms, a spring connected with the ladder and with said rod whereby to hold the ladder'yieldably inv a relatively raised position,a second crank arm on one of the fulcrum pins, and an operating rod pivoted to and rising from said second crank arm and slidably mounted on the ladder whereby the journals may be'rocked by a person on the ladder. v 4. The combination with a ladder, of housings secured on the sides of the same at the lowerend thereof, journalsfmounted in the sides of the housings, an axle carried by and,

between said journals and .eccentric thereto, a rock shaft connected with the journals, yieldable means acting on the rock shaft to, hold the ladder normally in relatively raised position, the ladder descending under the weight of a person thereon, and an operating rod connected with the rock shaft and slidably mounted on the ladder whereby the journals may be rocked by a person on the ladder to effect raising of the ladder.

In testimony whereof I affix my signature.`

HARRY E. BALLARD. [11. s]

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