US1953390A - Ladder - Google Patents

Description

` April 3, 1 934. Q H. BQSCH 1,953,390

LADDER Filed 001'.. 2, 1931 8 SheetS--Sheetv l ATTORNEYS C. H. BOSCH April 3, 1934.

LADDER 8 sheets-sheet? 2 Filed 0017. 2, 1931 M s R n w mmkm @Anf-JH April 3, 1934 c. H. BOSCH 1,953,390

LADDER Filed 001'.. 2, 1931v 8 Sheets-Sheet 5 ATTORN EYS April 3, 1934. C, H, BOSCH 1,953,390

LADDER .Filed oct. 2. 1951 a sheets-sheet' 4 ATTORN EYAS C. H. BOSCH l prl 3, 1934.

LADDER 8 Sheets-Sheet 5 Filed OCT.. 2, 1931 l N V E N T O R M/QfSMw/P//osc/x ATTORNEYS April 3, 1934. C. H. BQSCH 1,953,390

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` LADDER Filed Oct. 2, 1931 8 SheetS-Shee',- 7

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INVNTQR ATTORNEYS Patented Apr.' 3, 1934 LADDER Charles Henry Bosch, Brooklyn, N. Y., assignor to I Metropolitan Device Corporation, Brooklyn, N. Y., a corporation of New York 'Y Application october 2, 1931, serial No. 566,481

7- Claims. (Cl. 228-6) This invention relates to various features relating to the construction of ladders and while not limited thereto vthe invention is particularly useful in connection with extension ladders mounted pivotally for angular adjustment on a supporting frame carried by a vehicle such as an automobile truck or the like.

One feature of the invention relates to the provision of an extension ladder in which one sec- 10 tion is spanned by two sets of spaced rungs with another section slidable longitudinally betweeri said sets of rungs.

Another feature of the invention relates to means for reinforcing the rung structure of the ladder. Other features relate to means for automatically preventing the operation of the automobile engine so long a's the ladder is in its upright or working position.

A further feature relates to locking means for releasably holdingthe ladder in various positions of angular adjustment. Another feature relates to cushioning means for supporting the ladder for transportation.

A further feature relates to means for control- 5 ling the circuit through a stop or signal light when the ladder is in non-operative position. A fur- -ther feature relates to a safety device adapted to prevent pivotal movement of the ladder beyond a` predetermined angular position and 1means for tripping such device automatically when the extensible section reaches its lowered position.

Another feature relates to a disappearing auxiliary step or support which is carried by certain of the rungs and adapted to b e moved out of the Zvay when the'ladder is in position for transporta- Another feature relates to the provision of a tool basket or carrier adapted to be swivelled to the ladder and so arranged that it will hang plumb regardless of the position of the ladder.

' This permits tools to be left inthe container during transportation as well as whenthe ladder is in its non-working position.

Another feature relates to the provision of a .45 platform slidably mounted on the ladder and so arranged that it canbe collapsed to occupy a minimum amount of space'during transportation..

ladder which is angularly adjustable with re spect to the frame carried on the turn table. A further feature relates to an adjustable ladder provided with a prop pivotally connected 'thereto and adapted to lsupport the ladder in various inclined and various substantially horizontal positions.

' The above and other more detailed features ofthe invention willbe fully apparent from the vfollowing specification when read' in connection with the accompanying drawings, in which:-

Fig( 1 is a side elevation showing a ladder of my invention pivotally mounted on a frame carried by `an automobile truck, this view showing' rthe truck backed up against the curb with the ladder in position for supporting a workman in juxtaposition to the upper part of an electric light pole;

Fig. 2 is a view illustrating another position of a truck being pictured as parallel to the curb with a ladder swung in position to 'facilitate changing of electrodes in an arc lamp; this view also illustrates an auxiliary step which can be also used as a seat for supporting the workman in sitting posture;

Fig. 3 is a side elevation showing a ladder swung to horizontal position prior to telescoping in the main pivotally supported sectionv of the ladder;

Fig. 4 is a front elevation of the ladder and its supporting frame, the extension section being shown in this view as telescoped within the main section;

Fig. 5 is a' section taken on line 5-5 of Fig. 4;

Fig. 6 is a detail view illustrating a swivelled support for a tool box or container;

Fig. 7 is a detail section showing one of the side rails of the ladder and means for reinforcing 'and anchoring one of the rungs;

Fig. 8 is a horizontal section on line 8-8 of Fig. 7; f

Fig. 9 is a vertical section on line 9--9 of Fig. 7;

Fig. 10 is an enlarged detail illustratingfa supporting means for a disappearing step;

Fig. 1l is an elevation from the right side of Fig. 10 with parts shown in section in the interest of clearness:

Fig. 12 -is a view similar to Fig. 10 showing the ladder .opposite'ly inclined and the step reversed;

Fig. 13 is a horizontal section on line 13-13 of Fig. 11;

- Fig. 14 is a view of a portion of a ladder and its Asupporting means diagrammatically illustrating means whereby the operation of the engine is prevented so long. as the ladder is in its erect position, the view also showing means for closladder is in its erect position;

Fig. 15 is an enlarged detail view of the bottom end of the main ladder showing the locking or latching means adapted to hold theladder 1n position and also illustrating a light control switch associated therewith;

Fig. 16 is an enlarged vertical section on line 16-16 of Fig. 15;

Fig. 17 is a detail view illustrating the safety latch adapted to prevent swinging' movement of the ladder in the'event that the latching means shown in Figs. 15 and 16 should not properly function;

Fig. 18 as viewed from the left is a detail sec tion on line 18-18 of Fig. 17; A a

Fig. 19 is an enlarged detail vertical section showing the upper end of the ladder supporting frame and means for pivotally securing'the ladder thereto, the view being a section on line- 19-19 of Fig. 20;

Fig. 20 is an elevation showing the ladder supporting frame and a portion of the ladder in the position for transportation;

Fig. 21 is a detail view showing means for closing the ignition circuit for an engine when thel ladder is in the transporting position of Fig. 20; Fig. 22 is a perspective detail view showing a l rest and positioning means thereon adapted for supporting the ladder in substantially horizontal position for transportation;

Fig. 23 is a rear view of an automobile carrying a turn table to which is secured a frame for pivotally supporting the ladder, the ladder being provided with a longitudinally adjustable workman supporting platform;

Fig. 24 is an enlarged view of a supporting platform which is adapted to be collapsed against a structure slidable lengthwise of the ladder, the ladder being shown in broken lines in this view in the interest of clearness;

Fig. 25 is a top view showing the nested ladder sections illustrated in broken lines in Fig. 24, and also the platform supporting structure.;

Fig. 26 is a'n enlargeddetail section on line 26-26 of Fig. 24;

Fig. 27 illustrates the collapsed position of the supporting platform as viewed from the right of Fig. 24;

Fig. 23 is a similar view as viewed from the plane indicated by the line 28-28 of Fig. 24;

Fig. 29 is a view similar to Fig. 24. but showing the parts moved to collapsed position;

Fig. 30 is an enlarged detail section'on line 30-30 of Fig. 27 illustrating means for releasably locking the collapsible platform in its collapsed position;

- Fig. 3l is a detail section on line 31-31 of Fig. 29;

Fig. 32 is a side elevation similarto Fig. 1 but showing the ladder supported from a turn table and also illustrating a prop pivotally secured to the ladder;

Fig. 33 is a view of the device shown in Fig. 32, but swung to a different position illustrating a prop adapted to support the ladder carried by the turn table in various horizontal positions of angular adjustment;

Fig. 34 is a plan view showing the ladder in full lines in position for transportation and in dotted lines swung to a position of angular adjustment as shown in Fig. 33;

Fig. 35 is an enlarged vertical section showing an anti-friction turn table for the ladder supporting frame of Figs. 32 and 33;

ing the circuit through a stop light when theA Fig. 36' is an enlarged detail section on line 36-36 of Fig. 33;

Fig. 37 is a view illustrating a modification which in some cases may be used as an alternative for the construction shown in Figs. 10 to 13 inelusive;

Fig. 38 is a View illustrating a further alternative form of disappearing step.

A Referring in detail to the drawings, 10 represents an automobile of the type commonly known as a light delivery truck. In the form illustrated in Figs. 1 to 3 the automobile has xedly secured thereto a supporting frame 12 which is adapted to pivotally support the main section 14 of a ladder which is also provided with an extensible section 16. i

The frame 12 as shown consists of a pair of upright substantially A-shaped members which at their respective apexes support atrunnion or pivot shaft 18 which passes through suitable apertures formed in-the bearing brackets 20 secured to the main section 14 of the ladder.

The main section of the ladder comprises side rails 22-22 (Figs. 4, 7, 8, 9 and 19). These side rails are spanned by two parallel sets of rungs 24 and 26.

The extension section 16 of the ladder is slid.-

The rungs of both the main and extension ladder.

are of substantially the same construction so a description of one will suffice for all. This con-` structionis shown in detail in Figs. 7 -to 9 inclusive. -As illustrated, each rung is of wood and is grooved at diametrically opposite points, as indicated at 34-34, to form seats for reinforcing rods 36-36 which extend through suitable openings piercing the side rails. -At each end of the run, there is a thimble or sleeve 38 which is perforated to permit the passage therethrough of the reinforcing rods 36. .The side rails are also provided with reinforcing metallic straps 40 at the points where the rods pas's through. The rods 36 are held by nuts 42 as shown in Fig. 8. The reinforcing straps 40 Aat the points remote from the rungs are secured to the side-rails by bolts 44. This arrangement provides a rung anchorage which can be conveniently made near the edge of the side rail. This is of importance in connection with va double rung ladder, it being understood that it would be objectionable to bore a hole near the edge of the side rail to receive the ends of the rung. The reinforced rung structure being secured by two rods gives a double safety feature.

The extension section 16 of the ladder is adapted to be extended and lowered in a manner commonly used for extension ladders by means of a suitable rope or cable 46, one end of which is secured as at 48 to an upper rung of the main ladder and passes over suitable sheaves 50 secured near a lower part of the extension section, the cable passing over a pulley 52 and being secured to a pull-in cable 54 which may be tied to two sets of lower rungs, asindicated at 56. The ex- For holding the ladder in its various positions of upright, or inclined angular adjustment, I pro-.

vvide an improved` locking means which in addiy presence of the workman and means are also proinclusive.

vided in combination with the ladder locking or positioning means for preventing the operation of the automobile engine during the time the ladder is in its erect or working position.

These means are best shown in Figs. 14 to 21 supporting frame 12 carries an arcuate bar 60 provided at suitable locations with apertures 62 adapted to accommodate the lower extremity oi" a locking latch rod 64 which is slidable within a sleeve-like casing 66. This rod has a stem 68 surrounded by a compression spring 70 and its upper end is formed of an eye to which is connected a flexible cord -72 which passes'over a grooved pulley 74 and carries onits extremity a finger ring 76, As thus arranged, it is clear that a pull on the finger ring will retract the latch rod 64 from the opening 62 and thus permit the ladder to be adjusted angularly about its pivotal support 18.

The lower extremity of the latch -rod 64 is adapted to engage a contact 78 which is connected by wires 80 with an electric light 82 (Fig. 14)

adapted tobe illuminated when the ladder is in its erected or working position. The light will usually shine through a red globe on the lower portion and through a suitable lens at the upper portion which will illuminate the ladder and the work. The light is connected by means of another wire 83 to a manually controlled switch 84 and by a wire 86 to one side of a battery 90. The other side of the battery will usually be grounded to some metallic part of the framework, as indicated at 92.

The latch rod 64 being of metal will also be grounded to the frame. As thus arranged, whenever t-he latch rod engages one of the contacts 78. (3 bcng shown in Fig. 14) a circuit will be completed through the light 82, thus warning approaching vehicles of the presence of the workman. The flood light playing up the ladder will also give a warningof the presence of the work car carrying the ladder. So long as the `ladder is in a working position, the circuit to the ignition apparatus of the engine will be interrupted. As diagrammatically indicated in Fig. 14, the engine 94 is provided `with the usual form of distributor 96 connected by wires 98-98 with the ignition coil 100. VThe co'l is connected by means of wire 102 with a wire 86 leading to one side of the battery. 'Ihe other side of the battery is connected by wire 104 with one 'terminal' 106 The switch terminal 110 is adapted to be moved. by a spring or by its own resiliency out of cone tact with the switch terminal 106; For moving the terminal 110 into contactwith the terminal 106 so as to close the circuit between the two, I provide a cam 114 carried by a shaft 116 having an arm 118 thereon; This arm 118 coacts with As shown in Figs. 14 to 16, the ladder a lug '120 extending outwardly from a toggle link 122. 'I'his link is pivoted at 124 to the frame 12 and at 126 to anothertoggle'link 128 which in turn is pivoted at 130 to the main ladder. As thus arranged, when the toggle is swung to this horizontal or transporting position, the toggle links will be moved to the position of Fig. 20 where they move vslightly past dead center vand are prevented from further relative movement by pin 132 carried bythe link 128 and coacting with the end of the slot formed in the link 122.

YIn this position, the extension lug 120 will force the( cam operating arm 118 to the positlon shown in Fig. 21 so as to press the switch terminal 110 into engagement with the terminal 106 and thus close the circuit across the switch terminals. Thus so long as the ladder is in its inoperative position the ignition circuit for the engine will not be affected. However, upon breaking the toggle of Fig. 20 the arm. 118 will move clockwise .from the full line position'to the dotted line position shownin Fig. 2l. will permit thespring 110 to break its circuit with the terminal 106. Thus it will be clear that when'the ladder i is moved to its upright or working position the engine of the vehicle cannot be operated.V This ensures the safety of the workman.

Safety means are-provided to prevent the ladderl from swinging downward in the event that the locking bar 64 should be inadvertently withdrawn from the aperture 62 "before the operator has descended from the ladder or to prevent the ladder from falling in the event of breakage, damage, or failure of the locking bar 64 to properly operate. This safety latch mechanism is best shown in Fig. 17 and includes a latch member 134 pivoted at 136 to reinforcing straps secured near -the lower end of the main ladder section-14. This latch has a tooth 138 which, when engaged with the stop 140 secured to the bar v60, prevents swinging movement of the ladder in one direction; a similar latch reversely arranged will be secured on an opposite side rail of the ladder seas to prevent swinging movement of the ladder in the other direction. The safety latch has an arm' 142 which is bent around as shown in plan view in Fig. 18 so that its extremity 144 extends uinto the horizontal position for transportation as indicated in dotted lines in Fig. l.

`For supporting the ladder during transportation, it is desirable to hold it in a substantially horizontal position and t-o provide means for preventing relative longitudinal movement of the extension section 16 relatively to the main section .14. To these ends, I provide the restas shown in Figs. 1, 2, and 22. The rest includes a pair of uprights 148 which arc secured to the body or chassis frame structure of the automobile. These uprights are bridged at the top bya cross membe enabled to swing the ladder about its pivot 18v ber 150 which carries a pair of brackets 152 in 'which are mounted cushion members 154. These members .are formed at their upper ends with V-shaped notches 156 adapted to form seats for the'side lrails of the ladder sections 14 and 16. These .cushions are of fairly heavy' rubber stock` or of other like resilient material. The V-shaped In some cases, I also provide upwardly extend- 150 of the rest.

ing prongs 158 which are secured to the cross bar These prongs are curved as shown and are adapted to be engaged by the rungs of the ladder sections as the ladder is swung downwardly. They are so placed on the cross rtension section of the ladder.

rest 150 so as to lie between the side rails of the ladder. These act as safeguards against sidewise displacement of the ladder in the event that the same should become dislodged from the notched seats in the cushion members 154. The prongs also prevent the extension ladder section from beingjogged outward in a lengthwise direction during travel of the car, it being understood that as they project between the rungsof the two ladder sections, these prongs of course would engage the rungs of theA extension section in the event the ladder had any tendency to move outwardly during transportation.

For insuring safety and increasing the comfort of a workman engaged in the task at the upper part of the ladder, I provide an auxiliary step which is adapted to be supported at least in part from the rungs. I also provide a container adapted to hold'tools used in his operations and also a safety strap so the workmanmay use both hands without fear of losing balance. These features are illustrated in Figs. 4 to 6, 10 to 13 inclusive, 37 and 38.

Fig-6 shows a tool basketor container 160 which has a pair of extensions 162 which are journalled on bolts 164 secured to the side rails of the ladder. These bolts also pivotally support a guard member 166 which may be in the form of a flexible strap made of leather, heavy canvas or the like. Or, in some instances, this strap may be made of light gauge bar iron. The pivotal support for the toolbox 160 permits it to hang plumb in the various angular positions to which the ladder may be adjusted. By its use it will also be understood that the workman Amay leave his tools in the box after he has completed his task, and when the ladder is swung to horizontal position for transportation, the tool box will rock on its trunnions and thus retain the tools in the basket which will also hang substantially plumb during transportation.

The auxiliary or disappearing step on which the workman is adapted to stand when working at or near the top of the ladder is best shown in Figs. 5 and 10 to 13. Modiled forms are also shown in Figs. 37 and 38. The step'of Figs. 10 to 13 includes a number of slats 168 which are secured to a metallic frame member 170 which is provided at its inner end with studs or projections 172 adapted to ride in slots 174 formed in plates 176 secured tothe side rails of the ex- The slot is so shaped and proportioned that the step may be positioned to project from either side of the ladder as will be clear from observation of Figs. 10 and 12. When the step is in use, it may be positioned as shown in Figs. 10 and 12. When in such position, it will be understood that the weight of the workman on the step will be taken jointly by the studs 172 and one of the rungs 30 or 32 of the ladder. When not in use the step may be swung to the dotted position illustrated in Fig. 10 where it disappears between the two sets of rungs. In this position, it will not interfere with the movement of the extension section relative to the main section of the ladder. Thus the disappearing step is desirable because it permits relative movement of the parts and a nesting of them together during transportation.

A modified form of step is shown in Fig. 37 in which the slats 168a are supported on side bars 178 of substantially V-shaped form as shown. At one end, the bar is formed with a hook-like portion 180 adapted to engage one rung of the ladder and with a forked portion 182 adapted to straddle a. lower rung. Fig. 38 shows a collapsing step in which the slats 168b are supported on side' bars, one of which is shown at 184. Each bar 184 is pivotally connected at 186 with another bar 188 having a fork 190 adapted for engagement with one of the rungs as shown. The form of step shown in Fig. 38 can be collapsed into engagement with the rungs as clearly shown in dotted lines in Fig. 38. When in this collapsed position, the two parts of the ladder can be moved relatively as will be understood.

Referring to Figs.' 23 to 31 inclusive, I have shown a crows nest or workmans supporting platform which is carried by a supporting structure slidable relatively to the main ladder section 14. This working platform is adapted to be collapsed against the slidable supporting structure and means are provided which are operable from a remote point for collapsing and releasably locking these parts.

Fig. 24 shows the platform in open or working position and Figs. 27, 28 and 29 show it in collapsed position. Referring in detail to these gures, the supporting structure indicated as a whole at 192 includes four angle bars 194, 196, 198 and 200. The bars 194 and 198 are spaced apart by sleeves 202 which surround throughbolts 204. Similar sleeves 206 space the bars 196 and 200. The bars 194 and 196 support a set of rungs indicated at 208. Similarly the bars 198 and 200 carry another set of rungs indicated at 210. 'As thus arranged, it will be understood that the supporting structure is of substantially rectangular form in plan as shown in Fig. 25. As thus arranged, it can be slid lengthwise of the main ladder section 14 which it surrounds.

The frame structure 192 is adapted to be moved relatively to the main ladder section by means of an operating cable 212 secured to a fitting 214 carried by one of the rungs 208. This cable passes over a pulley 215 supported from one of the rungs 24 of the main ladder section 14.

The workmans supporting platform indicated as a whole at 216 comprises a number of planks 218 secured to a marginal frame 220. This frame is in turn supported on light angle beams 222 which are provided with upwardly extending portions which are pivotally connected at 224 to the slidable frame structure 192. The beams 222 have secured in spaced relationship thereto bars 226 which are so spaced as to form guide slots 228.

Pivoted at 232 to each of the members 196 and 200 of the frame there is a movable strut 230. Each strut carries at its upper end a roller or pin 234 which projects into the slot 228. In the supporting position, the strut, as shown in Fig. 24 is adapted to take the weight of the platform.

The platform is preferably provided with a guard rail to prevent the workman from falling momentum will carry the parts.

l petasse oi. This guard rail is supported by uprights 234 pivoted at 236. These uprights are in turn pivoted to side guard rail members 238 which are pivoted at 240 to the angle members 196 and 200 of the sliding frame structure.- The assemblage is such that the platform, uprights 234 and guard rail members 238 can be swung or collapsed inwardly .from the position of Fig. 24 to the position shown in Fig. 29. This swinging or collapsing movement is adapted to be accomplished from a remote point for example from a point near the base of the ladder. To

collapse the structure, I provide a cable 242 which passes over a grooved pulley 244 secured .to the sliding frame 192 and around another pulley 246 carried on the swingable strut 230. The cable then passes around another pulley 248 '(Fig. 30) carried on a bracket 250 secured to the underside of one of the'planks of the platform 216. The end 252 of the cable is secured to an eye formed on a rod 254 which is fastened to a lockng bar 256. A spring 258 surrounds the rod 254 and is enclosed in a sleeve-like casing 260 which also serves as a guide for the locking bar, this casing being secured by suitable straps 262 to the underside of theV planks of the platform 216 as best shown in Fig. 30. The locking bar 256 is adapted to engage an aperture 264 formed in a locking plate 266 which is secured by bolts 268 to one of the members of the sliding frame structure 192.

The outer end of the plate 266 is inclined upwardly so as to exert sort of a camming action on the end of the lock bar 256 as the platform 216 is swung toward the sliding frame 192.

In collapsing the platform structure against the sliding frame, the operator pulls on the cable 242. This first tends to pull the'rod 254 toward the pulley 248. Then as the eye on the rod 254 engages the bracket 250 carrying the pulley any further force exerted on the cable tends to swing the movable strut 230 of Fig. 24 toward the sliding frame. At this time, the stud 234, sliding in the guide slot 228 rocks the platform 216 about its pivot 224 also collapsing the uprights 234 and the guard rail 238. As the operator continues his pull on the cable 242, the parts gather momentum andfinally come in contact with or immediately adjacent the sliding frame 192. As the parts approach this position, the operator will slightly release the pull on the cable 242, whereupon the At the same time releasing the tension of the cable permits the spring 258 to force the locking bar 256 out- Wardly and the inclined plate 266 cams the bolt into lockingengagement with' the slot 264 in the plate, thus locking the parts in the relative position shown in Figs. 27 and 30. rl`his collapsing and locking movement is accomplished from a remote point, for example, by the operator on the ground pulling on a ring 243,as indicated in Fig. 23.

When the auxiliary sliding platform 216 is used, l preferably provide means for taking the strain so as to overcome the tendency to rock the ladder dueto the eccentric loading thereof. For example, I may provide a guy wire 270 secured at 272 to an eye bolt fastened at the upper end of the main ladder section. The lower end of this guy wire being secured to a fitting 274 which is pivotally secured to an outwardly extending rod 276 which is journalled in a bearing member secured to a brace 278. The rod 276 isaligned with the pivotal mounting of the ladder so that the same can be readily swung without disturbing the relative position ofthe parts. The guy Wire will usually be provided with a turn buckle 280 so as to compensate for stretching of the wire.

As showin in Figs. 32 to 35 inclusive, the ladder supporting frame 12 is mounted on a turn table 282 rotatably supported on anti-friction bearings 284. A suitable lock 286 is provided forreleasably holding the turn table in any desired position of angular adjustment. With this turn table arrangement, it will be understood that the automobile on which the ladder is mounted can be positioned parallel with the curb of a street as shown in Fig. 32. In this position, the turn table permits the ladder to be swung outwardly at about right angles to the direction of the length of the car on which it is mounted. This is preferable in some cases as there is a minimum obstruction, when the car is so parked with its length extended in the direction of the length of the roadway. 'I'his figure also shows an adjustf able prop which serves to rigidfy the ladder. This is very useful when the car is positioned on a highly crowned road or Where the car is to be driven off the road on the side of a hill vor the like.

The prop in such case prevents any tendency for the Weight of the workman on top of the ladder to cause a turning over of the car. The prop, as shown, in Fig. 32 consists of a long rod A 288 pivoted at 290 at the point near the upper end of the main ladder 14. "I'his rod telescopically engages a tubular member 292 which is provided with a plurality of spaced holes 294v any one of which is adapted to receive a pin intended to lock the rod 288 relatively thereto. The end of the member 292 is provided with a pointed tooth 296 adapted to be forced into the ground or to be butted up against any suitable rigid member. The prop mayv also serve jointly with the frame 12 to Support the ladder in -substantially horizontal position,l as illustrated in Fig. 33.. This is very useful because the ladder can thus be used as a horizontal scaffold. It will be understood of course that the frame 12 being mounted on the turn table permits the prop to cooperate with the frame 12 so as to support the ladder in various positions of both vertical and horizontal angular adjustment.

As shown in Figs. 33 and 36, the ladder sections 14 and 16 may be provided with hand rails 298 and 30o. These being pivoted at 302 and 304 to the side rails of the ladder sections as shown in Fig. 33. With such an arrangement, I may pro'- -vide a narrow platform or so-called cat-walk 306 which can be conveniently hinged, as indicated at 308 to the uprights 310 which carry the hand rail. 'lhis arrangement of Figs. 33 and 36, provides a convenient and easily erected scaffolding for Working on store fronts or on other structures located fairly close to a roadway. The height of the supporting frame 12 and the adjustment of the prop is such that other vehicles as well as pedestrians can pass below the ladder scaiold Without interferencer While l have described in considerable detail various structural features of the embodiments of the invention illustrated herein it is not to be construed that I am limited thereto. 'I'he detailed description and drawings it is to be understood are to be interpreted in an illustrative rather than a limiting sense since various modications and substitution of equivalents may be made by those skilled in the art without departure fromv the invention as defined in the appended claims.-

What I claim is: 1. In combination with a motor vehicle and the engine thereof, a'ladder pivotally supported on the vehicle and means for rendering the engine inoperative automatically upon movement and a safety device operative to prevent movement of the ladder beyond a predetermined angular position, and means for tripping said safety device automatically when the extensible section reaches its lowered position.

3. A ladder having side rails and at least one set of rungs, a disappearing step adapted to be supported in part by one of the rungs, a step supporting member carried by one lof the side rails and a sliding connection between the step and said member.

4. A ladder having side rails and at least one set of rungs, a disappearing step adapted to be supported in part by one of the rung's, a. slotted member secured to one of the side rails and having a slotted portion adapted to partake of the support of said step in both its working and nonworking position, and supporting means carried by the step and coasting with said slotted portion.

5. A ladder -having a platform supporting structure slidable longitudinally thereof, a platform pivotally supported by said structure, a, strut pivoted to the structure and slidingly engaging the platform, means for swinging the platform and strut to collapsed position against said structure and means for releasably locking said plat form and strut in collapsed Kposition to said supporting structure.

6. A ladder pivotally mounted on a frame car- 'ried by a motor vehicle, a platform supporting structure slidable longitudinally of the ladder, a

platform supported by said structure, a strut pivoted to said structure, a guide carried by the platform, a member carried o n the free end lof said strut for coaction with said guide, a locking plate secured to the slidable structure, a spring pressed locking member carried by the platform and adapted to coact with said locking plate, an

operating cable connected at one end with said locking member, respective grooved pulleys carried by said platform, said strut and said supporting structure and around which said operating cable is trained.

. 7. A ladder having a platform supporting structure slidable longitudinally thereof, a platform pivotally supported by said structure, a strut pivoted to said structure and engaging said platformand means for swinging the platform and strut to collapsed position against said structure.

CHARLES H. BOSCH.

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