US1439388A

US1439388A - Stepladder

Info

Publication number: US1439388A
Application number: US475299A
Authority: US
Inventors: Benedict E Willett
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-06-06
Filing date: 1921-06-06
Publication date: 1922-12-19
Anticipated expiration: 1939-12-19
Also published as: DE395226C

Description

' of Fig.

Patented Dec. 19, 1922.

UNITED -sTATE's PATENT .oFFlcn BENEDICT E. WILLETT, or DAYTN, omo.

STEPLADDER.

Application jiled June, 1921. Serial No. 475,299.

a structure of this kind which will have al relatively large work platform; which can be readily folded into compact form; and which, when in its'extended o r operative position, will be very strong and rigid.

A further object of the invention is to provide the work platform with guards, to prevent the workman from falling and which will beof such a character that they will notl interfere with the folding of the structure into compact form.

A further object of the invention is to provide means for locking the structure in its extended position; and, further, to provide such locking means which will operate automatically when the structure is moved to its extended position.

A further object ofv the invention is to provide such a structure having castors which will be normally inoperative when the structure is subjected to the weight of the workman, but; which may be rendered operative by the workman when he is on said structure.

Other objects of the invention will appear as the structure isl described in detail. In the accompanying drawings Fig. 1 is a side elevation .of a step ladder embodying my invention; Fig. 2 is a transverse section taken on the line 2-2 of Fig.v1; Fig. 3 is a front elevationof" the structure of Fig. 1;- Fig. 4 is a side elevation of'said structure in its folded or collapsed position; `Fig. 5 is a ,section takenon the line 5 5 of Fig. l; Fig. 6 is a sectional View of portion of4 the ladder taken on the line 6-6 5 and showing the rear portion of the-l platform elevated; Fig. 7 is a detail view of one ofthe locking devices; and Fig. S is a section'takenonthe line 8-8- of Fig. 1; In these drawings I have illustrated one embodiment of my invention and have,

shown the same as comprising a rear. frame and a front frame provided with steps and of less'length than the rear frame. 'The front frameextends upwardly at a slight inclination to the rear frame and has its rear end spaced therefrom a distance suficient to permlt a relatively large work platform to be interposed between the same The twoframes are l'connected one to the other by suitable spac.-

and the rearv frame.

ing devices which are of such a character and so connected with the frames that they will permitthe frames to move one towa/rd the other, to collapse or fold the structureinto a compact form, and the work platform is so mounted on the frame that when the structure is collapsed, or folded, this platform will occupy a position substantially parallel with the frames.` Guard rails extend downwardly and forwardly from the upper end of the r'ear frame to the upper end of the front frame and are so connected withthe frames that they will fold alongside of the same when the two Aframes are moved one toward the other.

It willv be understood that these features :may be embodied in structures of various kinds, such for example, .as step ladders, scaifolds,.and the like, and that the structures' themselves .may be constructed in various ways without departing from the spirit of the invention, the present structure having been chosen lfor the purposeof illustration only.

In that form of the invention here illustratedthe front frame consistsof two side members, indicated as a whole by the reference numerall 10 and each consisting of an angle bar 11 and a iat bar 12 ari ranged in the rear'of the angle bar and connected therewith by connecting bars, or cleats, 13 which also serve as supports `for ste s 14. The bars 11 and12 are,'prefer ab y, also connectedat their upper. ends by a reinforcing plate 13a. The side frames are connected one' to the other` near their upper ends by a transverse bar, or plate `15 which is rigidly secured to the respective angle bars 11.

- The side frames are further connected and rigidly braced one against the other by the steps 14 which are rigidly secured to the' cleats. ,The lower ends of the-bars l1 and 12 of the respec.'

tive side members are rigidly connected one member a distance sufficient 'to brace the frame against any tendencyto t-ilt. Each tie plate 16 is provided with a brace, prefc1 ably-consisting of a bar having a horizontal portion 55. resting on and secured to the. plate and an inclined portion 56 extending upwardly from the outer edge of the horizontal portion and rigidly secured? to the i angle bar 11 at a point above the tie plate.

By thus constructing the frame members a very strong, rigid structure is provided and a maximum of strength is had with a In1n1- mum of weight.

consists of two angle bars 17 spaced apart, preferably a distance slightly greater than the width of the front frame, and secured atltheir lower ends to abase418 which may consistof'two anglebars having their ver- The rear frame` in the form here shown` tical, anges Iarranged back to back and rig'-V idly connected one to the other, that fiange of each vertical angle bar 17 which is parallel with the base extendingbetween and beinpP rigidly secured'to the two vertical flanges of the basc.- T he connection is reinforced by a brace 19 which is secured to the angle bar 17 and has its lower end secured to the base 13 and restino` upon the rear flange thereof. The angle bars 17 are braced against' the base by means of di` 'ago'nal brace bars 20', and the upper portions of the bars are rigidly connected one to Ithe other by transverse bars, or plates, 21 22 and 22, 'lhe rear frame is preferably supported vby swivelled casters 23 upon which the base-18jis mounted vand which facilitate t-he movement of the structure from one .position to another.

The front frame is of consideral'ily'less height than .therear frame and the two frames are connected` one to the other by

spacing members

24 and 25 which are of such a character and are so connected with the two frames that they: will permit the A. latter to be moved one toward the other. and

thus lie folded into a compact form. In the present construction the connecting devices vare so arranged that the front frame mem- .bermay be moved upwardly and rearwardly toward the rear frame and to this end the upper connecting device consists of two bars 24Qpivotally connected at their rearends to 'the respective angle bars 17 of the rear l ,frame and pivotally connectedat theirA forward ends with the respective sidev members of the front frame. In the present instance the. two members ofthe. upper: c'innectingl device arel 'pivotally connected at 25 with. the upper ends offthe bars 12 of the respec.

angle bars of the rear frame near the lowerl ends thereof and is pivotally connected at its `front end with the respect-ive side 1nembers of the front frame at points some distance above the lower ends thereof 'so that the connecting device extends diagonally of the structure. This lower connecting device maybe of any suitable character but. as here shown, it consists of side members, or bars, l26 and diagonal brace bars 27 hav ing` their central portions rigidly connected and diverging forwardly and rearwardly. The iront and rear frames are further connected by toggles 28 which, when the frames arein their extended positions, serve t0 retain the same in such positions but which will collapse when the two parts thereof are moved out of alinement one with the other to permitof the movement of the frames o ne toward the other.

A' platform 29 is mounted uponthe upper spacing device 24, which in' effect forms a part thereof, land extends ,between the two frames. thus providinpy a relatively large work platform vwhich will fold agalnst the rear frame, between the same and the front frame, when the front frame is moved upwardly and rearwardly toward the rear frame. If desired, the platform may be formed in two parts one of which may be supported in an elevated position to form a slvlpplementalwo-rlcplatform o'f a ,greater height than the main platform. As here shown, the rear portion 3() of the plat-form is connected with the members of Vthe spacing device 24 by links 31 which are connected withthe ends of the part' 30 of the platform near what is the rear edge thereof when the platform is in its normal position, and which are connected at their opposite ends with the sidemembers of the spacing device near the rear ledge of the fixed forward part of the platform, as shown at 32. When the platform is in its normal position, in which it constitutes-one largeplatto extend between the angle bars 17 of the. rear frame where, it is connected with and.

supported by theupper transverse bar 22 'of the rear frame, the part 3() being preferably provided fat its -edge with hooks 33 ilo shaped ends of the bars lie in recesses 34 inthe forward portion of the platform so that they do not project above the main l platform or form any obstruction thereon.-

Connected with the upper portion ofthe rear frame and extending downwardly -and forwardly therefrom are side rails 35 which, together with that portion of the rear-'frame above the platform, constitute a guard extending about three sides of the plat-form to preventthe workman from falling. The side rails are of such a character that they will fold alongside of the structure when the two frames are moved one toward the other. To this end, the side rails Vare pivotally connected at their 'upper ends with the rear frame, the connection preferably being made between the upper ends of the rails and forwardly extending arms 36, rigidly secured to the respective bars 17 and in the present instance, triangular in shape. These bars are curved downwardly and are slidably mounted at their lowerends in apertured lugs 38 which are pivotally mounted at 39'on the respect-ive side members of the front frame, the curvature of the rails 35 being such that as the front frame is moved upwardly and rearwardly toward the rear frame the apertured lugs will move along the respective rails and will ca-use these rails to move about their pivotal connections with the rear frame and to fold alongside of the collapsed structure. 'It is desirable that some means .be provided, other than the toggles 28, to positively lock the structure in its extended position to prevent any possi bility of its -being inadvertently collapsed while in use, and I prefer that such a locking device should be automatic so that it will assume its locking position, without action on the part of the workman, when the structure is -moved into its extended posi tion. This locking device may .take various forms but` I have accomplished the desired result in a very simple'way by locking the front frame and the side rails` 35 of the guard against relative movement and in this way preventing the front frame from being moved toward the rearfranie. so long as the locking device is in its operative position.

l [Toaccomplish this I have pivotally mounted i in line with the lower ends of the side rails on the respective side members of the front frame locking levers. 40, the upper ends of which are 4preferably bent laterally, as

shown at 41, and are adapted to be moved into and out of a position adjacent to and 35. The lower portions of the levers 40 are pivotally connected with levers 42 which ex-A tend downwardly along the side members of the front frame and are pivotally mounted on the adjacent arms of the toggles 28. The arrangement is such that when the toggles are broken to permit Athefframes to be moved one toward the other the locking levers will be moved into inoperative positions, or when the levers 42 are directly actuated to move the locking levers to inoperative positions the toggles will be broken. In either case a single operation releases both devices so that the frames arein a condition for folding. Likewise, when the frames are moved to their extended posit-ions the straightening of the toggles will move the locking levers int-o their operative positions after the side rails havecompleted their movement, so that the parts 41 will not engage the rails themselves but will move beneath the same. A spring 43 connected'with each lever 42 below its point of connection with the toggle, may, if desired, be employed to assist in moving the locking lever to its operat-ive position.

With the rear frame mounted on castors the structure Inay be moved from one po`sition to another, without great difiiculty, by lifting the front frame and allowing the device to travel on the rear castors, but l prefer to provide the front frame with castors, or rollers, to render the movement `of the structure moreeasily accomplished.

rangement being such that the front frame may be moved into and out of operative engagement with the floor by the movement of the frame 44 about its axis. Connected with the transverse bar 45 of the frame 44 is a spring 48, the upper end of which is connected With a suitable part of the front `frame and the tension of which is sufficient to overcome the weight of the structure and lift the front frame out' of engagement with .the floor, thus causing the front frame to be supported on the castors. The strength of the spring, however, is only slightly greater lthan that necessary to lift the front frame when thestructure is unoccupied and as soon as the structurey is 'subjected to the weight of thevworkman the spring will ield and the front frame will be moved into engagement with the loor, thus providinga firm, solidsupport for the front frame. Under some conditions of work it is desirable that the structureshould be movable while the workman is on the same and to permit this to be done I have provided means under the control of the workman for forcing the rollers, or castors, 47 into engagement with the floor and lifting the front frame out of engagement therewith.l To this end I have connected with the rear portion of the supplemental frame 44, a yoke 49, with t-he central portion of which is connected arod 50 which extends upwardly along the rear side of the front frame and is pivotally connected at its upper end with the forward end of a lever 5l which is pivot-ally mounted between its ends beneath the platform 29. The rear end of the lever 51 has connected therewith a plunger 52 which extends through an opening in the platform and projects above the same into a position in which it may bc readily actuated bythe workman. As the workman tl'. ows his weight on the plunger it will be`apparent that the lever will operate to lift the rear portionof the supplemental frame la and thus lift the front frame out of engagement with the ioor and to retain the same out of engagement therewith so long as the weight of the operator is on the plunger.

I have also shown the structure as pro vided with a tool box 57 arranged in a convenient position with relation to the platform Q9. As here shown, thir tool box extends between the upper ends of the angle bars l'T of the rear frame and serves to connect these bars one to the other. If de sired,'the tool box may be removable and, as here shown, 'it is provided at its ends with depending lugs 58 spaced from the ends thereof and forming hooks to engage over the respective arms 36 and connecting bar 22a, thus firmly attaching the tool box to the rear frame.

IVhile I have shown and described one embodiment of my invention I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention what I claim as new'and desire to secure byV Letters Patent, is

1. In a structure of the character described, a front frame, a rear frame to sup-- Yport said front frame, said rear frame being spaced from the upper end ofsaid front frame., a spacing device pivotally connected at its ends .with the respective frames and arranged to permit said frames to moveone toward the other, 'and a platform carried by said spacing device and arranged to be folded between said frames when the latter are moved one toward the other.

2. In a structure of the character de* scribed, a front frame,'a rear frame to Support said front frame, said rear frame being spaced from the upper end of said front frame, a spacing device connecting said frames one to t-he other and movable relatively thereto to permit said frames to move one toward the other, a platform movably mounted on said frames, and adapted to be moved into `a position alongside thereof when said frames are moved one toward the other, said rear frame having a part extending above said platform, and guard rails extending from said part of said rear frame to the upper end of said front frame, said rails being pivotally connected with said parts to permit them to fold along with said structure when said frames are moved one toward the other.

3. In aA structure of the character described, a front frame having steps, a rear frame to support said front frame, said rear frame being of greater height than said front frame, both the upper and lower ends of said front frame being spaced from said rear frame, spacing devices to brace said frames one against the other and so arranged that one frame may be moved upwardly and toward the other frame to collapse the structure, the uppermost spacing device constituting a support for a platform and being pivotally connected at its ends with said frames and arrangedy to fold against the upperportion of said rear frame between the same and said front frame.

4. In a.` structure of the character described, a rear frame, a front frame provided with steps and of less length than said rear frame', said front frame being spaced 100 throughout its length from said rear frame, and a. platformsupporting device extending from the upper portion of said front frame tosaidrear frame and pivotally connected with the respective frames, to permit one of 105 said frames to move .upwardly toward the other frame and a spacing device extending lupwardly and rearwardly from said front frame toward said rear frame.

5.I.1 a structure of the character describe-d, a rear frame, a front frame provided with stepsand of less length than said rear frame, said front frame being spaced throughout its length from said rearframe,

a platform supporting device extending from the upper portion of said front frame vto-said rear frame and pivotally connected a platform supporting device extending` thereof, side rails p-ivotally connected'with the upper end of said rear frame at@ the respective sides thereof and curved downwardly and forwardly and slidably mounted in the respective apertured lugs on said front frame.

7 In a structure of the character described, a rear frame, a front frame provided with steps and of less length than said rear frame, said front frame being spaced throughout its length from said rear frame, a platform supporting device extending from the upper'portion of said front frame to said rear frame and pivot-ally connected with the respective frames to permit said front frame. to move upwardly and rearwardly t-oward the rear filme, side rails extending downwardly and forwardly from the upper end of said rear frame and slidably connected with said front frame to permit the relative movement' of the two frames, and means to lock said rails against movement relatively to said front frame.

8. In a structure of the character describe-d, a rear frame, a' front frame provided with steps and of less length than said rear frame, said front frame being spaced throughout its length from said rear frame,

a platform supporting device extending fromthe `upper portion of said front frame to said rear frame and pivotally connected withthe respective frames to permit said front frame to `move upwardly and rear- A.wardly toward the rear frame, side'rails extending downwardly and forwardly from the-upper end of said rearfframe and'4 slid- 2lb-ly connected with said front frame to permit the relative movement of the two frames, and locking devices mounted on said front framev forv movement into and out of the paths ofsaid'. rails .to lock said front frame and said rails against relative movement.

9. In 'a structure of the character described, a rear. frame, a front frame provided with steps and of less length than said rear frame, said front frame being spaced throughout its length from said rear frame, a platform supporting device extending from the upper portion of said front frame .ably connected-with said front frame to permit .the relative movement ofthe two frames, locking devices mounted on said front frame for movement into and out of the paths. of said rails to lock said front frame and said rails against relative movement, and means controlled by the movement of said frames one from the other for moving said locking devices into line with said rails. x

10. yln a structure of the character described, a rear frame, a front frame provided with steps and of less length than said rear frame, said front frame being spaced throughout its length from said rear frame, spacing devices connecting said frames one to the-other and' arranged to permit the front frame to move upwardly and rearwardly toward the rear frame, toggles extending between said frames to hold the same in their extended positions, a work platform extending between said frames and vfoldable against said rear frame when the front frame ismoved toward the latten-and a device controlled by the movement of said Kframes to their extended positions to positively lock the same in those positions.

11. In a structure of the character described, a rear frame, a front frame provided with steps and of less length than said r'rear frame, said `front frame being spaced same in their extended positions, a work platform extending between said frames and foldable against said rear4 frame when the front frame is moved toward the latter, a device mounted on said front frame and actuated by said -toggles to positively lock said front frame agalnstmovement toward said rear frame. Y g v l2. In astructure of the character described, a rear frame, a front frameV provided with steps and of less length than said i rear: frame, said front frame being spaced throughout its length from said rear frame, ,spacingv devices connecting said frames one to the other and arranged to permit the front frame to move upwardly and rearwardly toward-the rear frame, toggles extending between said 'frames to hold the same in their extended positions, a work platform extending between said frames and foldable against said rear frame when the front frame is moved toward the latter, guides carried by the upper end of said front frame, side rails pivotally connected at their upper ends with said rear frame and -extending through the respective guides on the front frame, whereby the lower ends of said rails will be moved toward said rear frame alon with said front frame, and a locking devlce mounted on said front frame and arranged to be actuated by said toggles to lock said side rails and said front frame against i'elative movement.

13. In a structure of the character described, a rear frame, 'a front frame provided with steps and of less length than said rear frame, said fiont frame being spaced throughout its length from said rear frame, spacing devices connecting said frames one to the other and arranged to permit the front frame to move upwardly and rearwardly toward Athe rear frame, toggles ex tending between said frames to hold the same in their extended positions, a work platform extending between said frames and foldable against said rear frame when 'the front frame is moved toward the latter, Guides carried by the upper end of said front frame, side rails pivotally connected at their upper ends with said rear frame and extending through the respective guides on the front frame, whereby the lower ends of said rails will be moved toward said rear frame along with said front frame, a locking lever `mounted upon each `side of said front frame and having a portion .arranged to be moved into line with the end of the adjacent side rail when said structure is moved to its extended position and means for connecting said lever with one of said toggles to nove the locking part i'nto line with said rai i4. In a structure of the character described, a rear frame, a front frame provided with steps-and of less length than said rear frame, said frontY frame being spaced throughout its length from said rear frame, spacing devices connecting said frames one to the other and arranged to permit the front frame to move upwardly and rearwardly toward the rear frame, toggles extending between said frames to hold .the same in theirexten-ded positions, awork platform extending between said' frames,v

and foldable against said rear frame when the front frame is moved toward the latter,'guides carried by the upper end of saidfront frame, side rails pivotallyl connected at their upper ends with said rear frame and extending through the respective guides on the front frame, whereby the lower endsy of said rails will be moved toward said rear frame along with said front frame, a locking lever mounted upon each side of ,said front frame and having a portion arranged to be moved into line with the end of the adjacent side rail when said structure is movedto its extended position, and a second lever pivotally connected at one end with said locking lever and at its other end with one of said toggles, whereby the movement of said toggle will move said locking lever into and out of line with said rail. y I

15. In a structure. of the character described, a rear frame. a front frame having its upper end spaced from the rear frame,

spacing members connecting said frames one to the vother and movable relatively thereto to permitsaid frames to move one toward the other, and a platform extending between said frames and connected thereto for movement into a position alongside thereofl when said frames are moved one toward the other, said platform comprising a movable portion, and means for supporting said movable portion in an elevated position relatively to the main platform.

1G. In a structure of the character described, a front frame, a rear frame of greater height than said front frame, both the upper and lower ends of said front frame being spaced from said rear frame,

spacing devices so connected with said:

frames that the latter may be moved one toward the other, a platform mounted on said framesvand movable into a position alongside thereof when said frames are moved one toward the other, said platform comprising a portion movable into an ele` vated position, means connected with said 'movable portion for supporting the forward edge thereof, yand other means for connecting the rear edge of said lmovable portion with said rear frame.

17. In a structurei of the character described, a front frame, a rear frame of greater height than said front frame, both the upper and lower ends of the front frame being spaced from said rear frame, and spacing devices so connected with said frames that the latter may-be moved one toward the other, the uppermost spacing member constituting a support for a plat form and being arranged to fold alongside of said frame members when the latter are 'moved one toward the other, said platform comprisin a portion movable into amele- '-vated position relatively thereto, linksccn# nected at onevend with said movable tion of said platform and at the other end V edge of said movable portion of said platform with said rear frame.

18. .In a structure of the character described, a rear frame, and a front frame connected thereto for movement toward and from the same, means for holding said frames in spaced relation, castors for said frames, the castors for one frame being movably connected therewith to permit said frame to be moved into and out'of contact with the floor and a spring interposed` between said fram( scribed, a rear frame, a frontframepconnected thereto for movement toward and from the same, means for holding said frames in spaced rela-tion, castors for saidV frames, the castors for one frame being movably connected therewith to permit said frame to be moved into and out of contact with -the floor, and means under the control of the workman on said structure to cause s aid frame to be moved out of engagement with the iioor.

V 20. In a structure of the character Ydescribed, a. rea-r frame, a front frame spaced from said rear frame and movable toward and from the same, a platform carried by said frames, castors for said frames, the castors for one of said frames being movably connected therewith to permit the frame to lmove into and out of-contact with the floor, and an operating device arranged ad- `jacent to said platform and connected with said frame and said castors tocausethe frame to be moved out of contact with the ioor.

21..In av structure o-f the character described, a rear frame, a front frame spaced from said rear frame and movable toward and from the same, a platform carried by said frames, castorsfor said frames, a supplementaly frame pivotally mounted on said front frame and carryingthecastors thereof, an operating device mounted adjacent the said platform, and an operative connection between said operating device and said supplemental frame to cause the front frame to be lifted out of Contact with the floor.

22. In a structure of the character described, a rear frame, a front frame spaced from said-rear frame and movable toward and from the same, av platform carried by said frames, castors for said frames, a supplemental frame pivotally mounted on said front frame and carrying the'castors therefor, a` spring interposed between said supplemental frame and said front frame to hold the latter normally outof contact with the floor, said spring being of such strength that it will yield under the weight of the workman on vsaid structure to permit said front frame to move into contact with the floor. an operating device mounted adjacent to said platform, and a connection between said operating device and said supplemental frame to cause said front frame to be moved out of contact with the floor.

23. In a structure of .ther character described, a front frame having steps, a rear frame to support -said front frame, said rear frame being of greater height than said l tween front frame, both the upper and lower ends of said front frame being spaced from said rear frame, and a spacing device pivotally connected at its ends with said frames to enable one frame to be moved upward and toward the other frame to collapse said structure and fold said spacing device besaid frames, and a platform carried by said spacing. device. v v24. In a structure of the character described, a front frame having steps, a rear frame to support said front frame, said rear frame being of greater height than said front frame, both the upper and lower ends i of said front frame being spaced from said rear frame, and a spacing device pivotally connected with said frames to permit one frame to be moved upwardly and toward the other frame to collapse said structure, and a platform extending between and pivotallyv connected with the upper portion of the front frame and therear frame and movable into a position between said frames when said structure is collapsed.

25. In a structure of the character d e. scribed, a front frame having steps, a rear frame to support said front frame, said rear frame being ofv greater heightl than said front fi'ame, both the'upper and lower endsv of said front frame being lspaced from said rear frame, and a spacing member so connected with said frames'that one frame may be moved upwardly and toward the other frame to collapse said structure, a platform extending between and pivotally connected with the upperportion `of the front `frame and with' the rear frame and movable into av position substantially parallel with said frames when said structure is collapsed, guard' rails arranged at the respective-sides of said platform, pivotally connectedl at their ends with the respective frames near the upper ends thereof and movable into positions extending lengthwise -of said frame when saidstructure is collapsed. 4

26. In a structure of the character de'- scribed, a front frame having steps, a rear frame to support said front-frame, both the upper and lower ends of saidfront frame being spaced from said rear frame, spacing devices to brace said frames one against the' other, said spacing devices being pivotally mounted at each end to enable one frame to be moved toward. the other frame to collapse said structure, one of said spacing' devices constituting Aa support'for a platform and being so arranged that said platform will be folded between the frames when. said structure is collapsed. Y

27. In a structure of the character described, a front frame having steps, a rear frame to support said front frame, said rear frame being of a greater height than said front frame, boththe upper and lower ends of said front frame `being spaced from said rear frame, a platform extending between the upper portion of said front frame and the rear frame, and movable into a position substantially parallel with said frames when said frames are moved one toward the other, and guard rails arranged at the respective sides of said platform, and so connected with the respective frames that they will be moved into positions in which they extend lengthwise of said frames when said frames are moved one toward the other.

28. In a structure of the character described, a front frame having steps, a rear frame to support said front frame, said rear frame being of a greater height than said front frame, both the upper and lower ends of said front frame being spaced from said rear frame, a platforn'i extending between the upper portion of said front frame and the rear frame, and movable into a position substantially parallel with said frames when said frames are moved one toward the other, and guard rails arranged at the respective sides of said platform, and pivotally connected with the respective frames so that they will be moved into positions in which they extend lengthwise of said .frames when said frames are moved one towar'd the other.

29. In a structure of the eharactervdescribed, a front frame having steps, a rear frame to support said front frame, said rear fra-me being of greater height than said front frame, both the upper and lower ends of said front frame being spaced from said rear frame, a spacing` member so connected with said frames that one frame may be 'moved upwardly and toward the other frame to collapse said structure, a platform extending between the upper portion of the front frame and the rear frame and movable intoI a position substantially parallel with said frames when said structure is collapsed, and guard rails arranged at the respective sides of saidv platform and connected at their ends with the respective frames near the upper ends thereof, the connections between one of said frames and said guard rails being slidable.

30. In a structure of the character dcscribed, a front frame having steps, a rear frame to support said front frame, said rear frame being of greater height than said front frame, both the 'upper and lower ends of said front frame being spaced from` the rear frame, a spacing member so connected lwith said frames that one frame may be moved upwardly and toward the other frame to collapse said structure, a platform able, and means to lock said slidable eonnections against movement when said structure 1s in an extended position.

3l. In a structure of the character de scribed, a front frame having steps, a rear frame to support said front frame, said rear frame being of greater height than said front frame., both the upper and lower ends of said front frame being spaced from said rear frame, spacing devices so connected with said 'frames that they may be moved one toward the other, a platform arranged between and supported by said frames and adapted to fold between the same, guard rails extending between said frames at each side of and above said platform and pivotally connected with the respective frames to enable them to be moved into positions in which they extend lengthwise of said frames when the latter have been folded one against the other.

In testimony whereof, I affix my signature hereto.

BENEDICT E. IVILLETT.