US 3731947 A
A foldable trolley which can be attached to an extension ladder or to any other heavy ladder and provides a way of easily moving the ladder about on the job. The trolley consists of a wheeled and foldable frame which includes hooks for engaging certain rungs of the ladder so that the ladder can be wheeled about while in a substantially upright position. The trolley folds up when the ladder is in use.
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Description (OCR text may contain errors)
lllie tates atet 11 1 l ontaine 1 1 May%,l973
 LADDER TROLLEY  Inventor: Lawrence A. Fontaine, 3035 Charles Street, Vancouver, British Columbia, Canada 22 Filed: June 3, 1971 21 Appl. No.: 149,652
52 vs. C! ..280/36 R, 182/127, 280/79.1 51 1m. 01. .sszu 11/110  Field of Search ..280/36 R, 79.3, 79.1;
 References Cited UNITED STATES PATENTS 1/1940 Moen ..l82/l2.7 5/1952 Hooz ..280/36R Fleck ....280/41 R Hulburt "280/793 Primary ExaminerBenjamin Hersh Assistant ExaminerRobert R. Song Attorney-Fetherstonhaugh & Co.
 ABSTRACT A foldable trolley which can be attached to an extension ladder or to any other heavy ladder and provides a way of easily moving the ladder about on the job. The trolley consists of a wheeled and foldable frame which includes hooks for engaging certain rungs of the ladder so that the ladder can be wheeled about while in a substantially upright position. The trolley folds up when the ladder is in use.
3 Claims, 41 Drawing Figures PATENTED HAY 81973 LAWRENCE A. FONTA INE LADDER TROLLEY This invention relates to the use of heavy ladders such as extension ladders and is particularly concerned with trolleys which can be attached to such ladders so they may more easily be moved about the job site.
All straight ladders including extension ladders, which are used by leaning them against the building, wall etc. to be scaled, are relatively awkward to handle as compared to lighter duty ladders such as those of the step ladder type. Even a so called light extension ladder can be very awkward to handle if it exceeds feet or so in length as most ladders do. The reason for these awkward handling qualities is that when one tries to manipulate anything that is relatively long as compared to its width and is doing the manipulating at one end only, high leverage effects tend to magnify the movements of the opposite end. Actually, the awkward handling qualities of extension ladders are most apparent when moving the ladders about on the job rather than when transporting the ladders to and from the job site.
The ladder trolley of the present invention is there fore most useful in overcoming the awkwardness of moving a ladder about on a job site. The trolley essentially consists of a wheeled and foldable frame which can be attached to a ladder at two spaced points. When in the unfolded configuration it constitutes a threewheeled trolley which carries the ladder in an upright position more particularly in an upright position which is sloped approximately to the same degree that a ladder is sloped when it is rested against a building. When the ladder is to be used i.e. when a workman is about to climb it the trolley is folded up in such a way that it swings out of contact with the ground. Thus when the ladder is in use none of the loads that are supported by the ladder are carried by the trolley.
An embodiment of the invention is illustrated in the accompanying drawings in which:
FIG. 1 is a perspective view of a ladder trolley in accordance with this embodiment of the invention, the ladder to which the trolley is attached being shown in dashed lines,
FIG. 2 is a side elevation view of the trolley illustrated in FIG. l with the trolley being in its folded configuration, and
FIGS. 3 and 4 are enlarged perspective views of certain parts of the trolley shown in FIGS. 1 and 2.
The trolley 10 of this embodiment essentially consists of a wheeled lower assembly made up of a transverse axle ll2 carrying a pair of freely rotating wheels 14 at its ends and a longitudinally extending frame member 16 which is rigidly fixed to transverse member H2 at its inner end and carries a castored wheel 18 at its outer end.
Pivotally attached to the above described wheeled In the case of the lower assembly, the hook members are carried at the outer ends of a U-shaped bracket 22. Each hook member consists of a fixed hook 24 and a sliding hook 26, see FIG. 3. The sliding hook is carried by a tubular sleeve 28 which also carries, on its top face, a locking unit consisting of a latch 30, pivotally connected to an upstanding ear 32. The outer end of the latch wedges against a stop member 34 fixed to bracket 22, when hook 26 has been advanced to engage the underside of the rung on which fixed hook 24 has already been engaged. Thus, with latch 34) wedged against stop 34!, slide 28 and its hook 26 are prevented from moving relative to fixed hook 24. With both hook members carried by bracket 22 being engaged on a rung in this way, the lower assembly 10 is effectively locked on the ladder involved.
In the case of the bracing member 20, the hook members consist of opposed fixed hooks 36 and 38. They are sized, shaped and spaced from one another in such manner that they can be slipped over a ladder rung when oriented in one way and locked against removal from the rung when oriented a second way.
In FIG. 8, the first orientation is shown in dashed lines, with the arrow showing the direction of movement to gain the second orientation. By comparing FIG. 4 with FIG. 1, it can be seen that the bracing unit is attached to the ladder by bringing the ends of rods 21 together, engaging the hooks 36 and 38 on a rung and then spreading the rods apart. To permit this action, the rods are pivotally connected together by a pivot pin 40. At their lower ends, rods 21 are pivotally and releasably connected to axle 22, as previously mentioned.
Longitudinal member 16 is adapted to be folded upon itself by a hinge at 62, there being a longitudinally slidabie locking sleeve 44 carried by the member and sized to slide over the hinge so as to lock the member 16 in its fully extended position.
As a further preferred expedient, longitudinal member 16 can be separated into two pieces at a lockable release point 416. Thus, the trolley can be broken down for each transport in an automobile, for instance, into three parts, namely, axle 12 having wheels 14 and the inner end of member 16, the outer end of member lb and a third part consisting of the bracing unit 20.
The manner in which the trolley is used is readily apparent from the drawings. FIG. ll shows the relationship between the trolley and a ladder when the ladder is being wheeled about on a job site. The hooks 24-26 of the lower wheeled assembly are engaged on the lowermost rung of the ladder while bracing unit 20 has its hooks engaged on a rung at some distance from the lower end of the ladder. Obviously, the user can select the best slope to the ladder while it is being transported by electing to hook the bracing unit 2f]! to a higher or lower rung. In selecting the slope of the ladder the user will find for each ladder there is a slope that distributes the weight of the ladder on the three wheels of the trolley most equitably. In the case of extension ladders the preferred slope will vary as the length of the ladder is varied.
When a ladder is in use i.e. is supporting the weight of a workman the trolley is folded into the position shown in FIG. 2. As can be seen, all three wheels of the trolley are out of contact with the ground and the load carried by the ladder is transmitted through the ground directly through the ladder rails in the normal fashion.
Transportation and storage of the trolley when not connected to a ladder is facilitated by leaving longitudinal member 16 in its extended position and simply folding bracing unit 20 into parallelism with the lower assembly. In this regard it is advantageous to dimension the bracing unit relative to the lower assembly so that they are roughly the same size when folded upon each other. Further, the trolley can be broken down into three parts, as previously described.
1. A ladder trolley comprising a lower assembly which includes a transverse axle carrying a freely tuming wheel at each end thereof and a longitudinally extending frame member rigidly fixed at one end to said transverse axle at a point substantially midway between said wheels and extending at right angles to said axle, said longitudinal member carrying a castored wheel at its opposite end, means for detachably connecting the longitudinal frame member to the lower end of a ladder, a bracing unit pivotally attached to the lower assembly at one end and carrying at its opposite end means for detachably connecting that end of said bracing unit to the ladder at a point some distance from the lower end of the ladder, said longitudinal frame member being hinged intermediate the length thereof to permit folding open itself, manually releasable locking means for preventing said longitudinal frame member from folding upon itself, said means for detachably connecting the longitudinal frame member to the lower end of a ladder comprising a bracket member rigidly attached to the longitudinal member and having a pair of hooks for engaging a ladder rung, one of said hooks being movable relative to the other hook and lockable in a position whereby said ladder rung is gripped between the hooks.
2. A ladder trolley as claimed in claim 1, in which said bracing unit consists of a pair of compression members which are pivotally fixed at their inner ends to the transverse axle of the lower assembly and having hooks at their outer ends for engaging the rung of a ladder.
3. A ladder trolley as claimed in claim 1, in which said manually releasable locking means consists of a slidable locking sleeve adapted to move on and off said hinge to render the hinge inoperative and operative respectively.