US3566990A

US3566990A - Portable scaffold

Info

Publication number: US3566990A
Application number: US783191A
Authority: US
Inventors: Anthony T Fredricks; Paul F Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-12-12
Filing date: 1968-12-12
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02

Abstract

A portable scaffold having a pair of caster-mounted ladder ends joined by a vertically adjustable platform. The casters have brake shoes which can be applied remotely from the platform to stop swivel of the casters and rotation of the caster wheels. A pair of sliding members, vertically slideable along the ladder sides, is connected to the platform enabling sliding adjustment of the platform. Pivoted locking brackets carried by the glides provide selective locking of the platform at different positions along the ladder sides. Butt hinge halves at the top of each ladder, releasable and adjustable corner braces and quickdisconnect pivotal connections of the platform with the glides permit folding of the platform into a compact package and also permit quick conversion of the two ladder ends into a trestle ladder or the ladder ends separately into two lockable, castermounted straight ladders.

Description

United States Patent [72] inventors Anthony T. Fredricks 3,463,265 8/1969 Clover 182/17 25 Horizon Drive Primary Examiner-Reinaldo P. Machado smnh 4621 Mountam Attorney-Buckhorn, Blore, Klarquist and Sparkman Bo1se,lowa [21] App1.No. 783,191 [22] Filed Dec. 12, 1968 [45] Patented 1971 ABSTRACT: A portable scaffold having a pair of castermounted ladder ends joined by a vertically adjustable plat- [54] PORTABLE SCAFFOLD form. The casters have brake shoes whichf can be applied 21 Claims, 13 Drawing Figs remotely from the platform to stop swivel o the casters and rotatlon of the caster wheels. A pair of sliding members, verti- U-S. ally lideable along the ladder sides is connected to the plat. 182/21 182/271 182/1 19, 182/152 form enabling sliding adjustment of the platform. Pivoted [51] Int. Cl E04g 1/30 l i b k carried by the glides provide selective [50] Field of Search 182/119, locking f the l tf at diff t positions along the

ladder

118, 63, 152, 17, 16, 21, 2 sides. Butt hinge halves at the top of each ladder, releasable 280/(Inqu11'ed); ISO/(inquired); 133/29, 1 and adjustable corner braces and quick-disconnect pivotal connections of the platform with the glides permit folding of [56] References cued the platform into a compact package and also permit quick UNITED STATES PATENTS conversion of the two ladder ends into a trestle ladder or the 2,335,046 11/1943 Droeger 182/119 ladder ends separately into two lockable, caster-mounted 3,061,949 lQ/ 1 9 62 Bran ley 16/35 straight ladders.

PATENTEUHAR 2 l9?! SHEET 1 BF 6 ANTHONY T. FREDRICKS PAUL F. SMITH INVENTORS BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS PATENTEU m 2m:

SHEET 3 [IF 6 F RED RiCKS INVENTORS ANTHONY T.

PAUL F. SMITH BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS PATE-Nnumm 3,566,990

SHEET 4 0F 6 ANTHONY T. FREDRICKS PAUL F. SMITH By lNVENTO/RS.

BUCKHORN, BLORE, KLAROU/ST a SPAR/(MAN ATTORNEYS PATENTEU m 219m SHEET 5 BF 6 ANTHON Y T. FREDRICKS PAUL F. SMITH IWVENTORS.

VBUCKHOR/V, BLORE, KLAROU/ST a SPAR/(MAN ATTORNEYS PORTABLESCAFFOLI) BACKGROUND OF THE INVENTION mounted prior scaffolds have been equipped with brakes which must be manually applied at each caster wheel, thereby resulting in additional time loss when moving from place to place. Some prior scaffolds have tried to increase compactness and portability by providing telescoping parts, but this has only added to the number and difficulty of adjustments and time required in setting up, adjusting and collapsing the scaffold. I

SUMMARY or THE INVENTION The problems of prior scaffolds have been overcome in the present invention by combining in a single scaffold structure;

l. remote operator controlled caster brakes which can be applied or released while the workman remains on the scaffold platform;

2. remote controlled caster brakes which can be applied in any position of the caster wheels;

3. caster brakes which prevent swiveling movement of the casters as well as rotation of the caster wheels;

4. a fast simplified sliding adjustability of the scaffold platform for height;

5. a positive, easily applied and released platform locking mechanism, the locking action of which increases with increased loading of the platform;

6. collapsibility of the scaffold into a compact package quickly and without disassembly of the scaffold components;

7. convertability of the scaffold into a trestle ladder or straight ladders quickly and easily;

8. rigidity of the scaffold while erected without collateral cross members or bracing other than that provided by the platform itself and its corner braces; Q n

9. lightweight, metal channel construction which enhances portability and rigidity of the unit;

It). increased portability while collapsed through utilization of the casters; and v 11. interchangability of parts for varying overall height and length of scaffold structure.

BRIEF DESCRIPTION OF TI-IE DRAWINGS the line 3-3 of FIG. 1;

FIG. 4 is a view of the scaffold of FIG. 1 shown in a folded condition;

FIG. 5 is a fragmentary end elevational view on an enlarged scale taken approximately along the line 5-5 of FIG. 1;

FIG. 6 is a view partly in section taken approximately along the line M of FIG. 5 showing the brake assembly on an enlarged scale;

FIG. 7 is an end view of a second form of scaffold in accordance with the invention;

FIG. 8 is a partial side elevational view of the scaffold of FIG. 7; K i

FIG. 9 is a perspective view of a third form of scaffold in accordance with the invention;

FIG. 10 is a perspective view of the scaffold of FIG. 9 converted to a trestle ladder;

FIG. 11 is a perspective view of the scaffold of FIG. 9 in a collapsed condition;

FIG. 12 is an enlarged side elevation of the brake assembly of the scaffold of FIG. 9; and

FIG. 13 is an enlarged side view of the glide assembly of the scaffold of FIG. 9.

DETAILED DESCRIPTION With reference to the drawings, FIG. 1 illustrates a scaffold l0 includinga pair of upright ladder end members 12, 13 joined together by a platform cross member 16. Each end member is composed of apair of laterally separated inverted U-shaped

tubular side members

17, 18 joined together at their lower ends by a base member 20 and along their lengths by tubular rungs 22 joined to the'outer leg of each double-legged side member. The tubing of the endmcmbers is preferably thick-walled aluminum or other lightweight metal or alloy conduit. Base member 20 may comprise lightweight corrugated steel sheet material. Platform cross member 16 may be constructed of a pair of side-by-side but spaced apart aluminum channel members 24 joinedtogether by top and bottom planks 26,28 of wood or metal.

Each end member is supported at its base by a pair of swivel casters, indicated generally at 30. Because of the unique braking system to be described hereinafter, these casters are preferably of so-called open center construction wherein a swiveled yoke portion 32 of the caster is joined to a stationary top plate 34 thereof at an annular ball bearing connection 36 surrounding the swivel axis of the caster, thereby eliminating the usual king pin. An example of a suitable caster for this purpose is the 3100 series Rapistan swivel casters manufactured by Rapids-Standard Company, Inc. of Grand Rapids, Michigan. Of course, other wheel means may also be used, including rigid casters if desired, but a caster having an open center top support plate is preferred with the use of the illustrated braking means.

The scaffold includes a unique remote braking system whereby both caster wheels 38 of each end member as shown in FIG. 5 can be braked simultaneously by a worker on the scaffold platform 16. This enables workmen to guide the scaffold from place to place within a room or along a wall while remaining on the platform by releasing the brakes from the platform and then applying the necessary pressure against an adjacent wall or ceiling to move the scaffold and finally resetting the brakes from the platform at the new location.

As shown most clearly in FIGS. 5 and 6 the brake mechanism includes a brake shoe 40 frictionally engageable with the peripheral surface of a caster wheel 38, at a serrated braking surface 42. The brake shoe is moved into and out of engagement with the caster wheel by a brake arm 44 which extends axially through a center opening 45 of caster yoke 32 and topplate 34. Brake arm 44 engages a top surface of the brake shoe ata shoulder 46. A reduced portion of the arm extends through an opening in the shoe and terminates at an enlarged end within a recess in the braking surface to provide a pivotal connection of the arm to the shoe, whereby the shoe swivels with the wheel and the yoke 32 while arm 44 remains fixed against rotation.

The upper end of brake arm 44 forms a clevis which is pivoted to the outer end of a bell crank lever 48 which in turn is pivoted at 49 to a lever support member 50 on ladder base 20. The opposite end of bell crank 48 is biased by a tension return spring 52' to maintain brake arm 44 in an upper limit position wherein the brake shoe is disengaged from the caster wheel. A short length of cable 54 is anchored at its upper end to an anchor plate 56 and extends around a pulley 57 and is anchored at its lower end to the same end of the bell crank 48 to which tension spring 52 is attached. A corresponding but longer cable 55 extends from anchor plate 56 around a second pulley 58 and thence to the inner end of a second bell crank lever 48a for the braking mechanism of the opposite caster wheel 38 of the same ladder end member. Except for the slight difference in cable arrangement, the braking mechanisms for all four caster wheels of the scaffold are identical.

Anchor plate 56 is connected to a primary brake cable 60 which extends upwardly to one end of a manual brake-applying lever 62 pivoted at 63 intermediate its opposite ends to U- shaped side member 17 of the ladder end. Lever 62 includes a long handle portion 64 which, when in an upper position, maintains the brake shoes disengaged from their respective caster wheels. However, movement of the lever handle 64 downwardly shifts the cable-connected end of the lever to a raised overcenter position in which both connected brake shoes are applied to and held in braking engagement with their respective caster wheels 38 at the same time. A stop 65 on side member 17 abuts handle portion 64 of the lever 62 to maintain the cable end of the lever in a raised position until the brake lever is manually rotated in a counterclockwise direction to release the brakes.

The platform cross member is joined to the opposite ladder end members by a series of unique tubular sleeve joints which enable ready vertical sliding adjustment of the platform relative to the end members, to provide a simple yet safe and foolproof means for locking the platform member in its adjusted position relative to the end members. The joints also provide overall rigidity of the scaffold structure to such an extent that the platform cross member and attendant corner braces serve as the sole means of upright support for the end members, with no collateral cross members or bracing being required. This sleeve joint construction includes a pair of sleeve joints, indicated generally at 66, at each end of the platform. Each joint includes a vertical tube 68 slidable along the inner tubular leg of each double-legged side member l7, 18. The lower end of each tube 68 is fitted with a bracket 69 providing a pin connection at '70 for one end of a corner brace 72, the opposite end of which is connected by a bolt and wing nut fastener 73 to a projecting ear 75 of platform 16.

The upper end of tube 68 includes a U-shaped strap bracket 78, the legs of which project inwardly toward the opposite end member. A tapered loop strap end portion 80 of platform 16 fits between the opposite legs of U-strap 78 and retains a center bushing 82 as shown in FIG. 3. End bushing inserts 84, 85 within leg openings 86 of strap 78 form continuations of center bushing 82. A U-shaped locking member shown generally at 88 extends about the inner leg of tubular side member 18 and has legs 90, the outer ends of which are provided with openings 91 which also receive

end bushings

84, 85. A pivot pin 92 extends through both the end bushings and the center bushing and has a threaded end 93 which receives a wing nut 94 so as to pivotally connect the end straps 80 of platform 16 to adjustment sleeve 68. In this manner platform 16 is joined to both end members.

With brace strap 72 connected to the platform, a rigid connection which will resist twisting is provided between the platform and the end members despite the sliding height adjustment of the platform provided when locking members 91 are disengaged from their respective side members. However, with brace strap 72 disconnected from the platform, the end members can pivot freely relative to the platform, an advantage which will become more apparent hereinafter. The split bushing construction of the pivot connection, shown in FIG. 3, provides a quick-connect and disconnect coupling for joining the platform to or separating the platform from the end members simply by removal of the wing nut and pivot pin. This permits platform end strap 80 and its connected center bushing 82 to drop from the joint, without disassembly of the remaining components of the joint.

Referring to FIGS. 1 and 2, locking strap 88 provides for selective locking of the platform to the end members at any one of several predetermined levels as determined by openings spaced along the inner tube of side members R7, 18. The pivot axis of locking strap 88 is positioned so that when the locking strap is raised or lowered relative to the horizontal, its web portion 96 engages the inner leg of side member 18, but when between such limit positions, web portion 96 is spaced from such leg. However, web portion 96 is provided with a pin projection 98 on its inner surface which is adapted to project into the pin-receiving openings W0. Locking pin 98 is angled so that when inserted in one of the openings 100, the pin will project downwardly into such opening. Thus downward pressure on platform 16 urges the pin into more secure locking engagement with the end member. However, an upward thrust of the platform or tube 68, or of the locking strap itself forces the pin out of locking engagement with pin opening 100, after which downward pivoting movement of the locking strap unlocks the platform from the end member, thereby permittingrelative sliding adjustment of the platform along the end members. Web portion 96 of the locking strap in profile includes a projecting handle portion 102 to facilitate pivoting of the locking strap to its upper, locking position or lower, release position.

The quick-coupling connection of FIG} also provides for rapid conversion of the scaffold to a step ladder in the manner illustrated in FIG. 1. This is done simply by disconnecting one end of the platform, for example the left-hand end of FIG. I, from associated end member 12 byremoving wing nuts 94 and pivot pins 92 from the two pivot joints at such end and wing nut fasteners 73 from corner braces 72 at such end. This permits platform 16 to pivot freely about its pivot connection with right end member 13 after disconnecting corner braces 72a from the platform at the same end. When the desired angle between ladder end member 13 and platform member 16 is obtained, as shown in phantom lines in FIG. 1, corner brace 72a is reconnected to ear 75a of the platform at the appropriate one of several holes 74a provided in corner brace 72a for adjustability. When the platform and one end member are used as a step ladder in the manner described, the brakes for the caster wheels of end member 13 should, of course, be engaged.

Alternatively, ladder ends 12 and 13 can be used separately as straight ladders, if desired, by disconnecting them from the platform and engaging their respective caster brakes.

The foregoing construction also provides a scaffold which can be folded into a compact unit with the end members and platform member lying parallel and contiguous with one another and with the folded unit not being appreciably greater in length than the height of the unit erected, as shown in FIG. 4. Collapse of the scaffold is achieved by disconnecting corner braces 72, 72a from the platform at their

connections

73, and 73a, respectively. The locking pins on locking straps 88 are then released from the end members so that the platform can pivot and slide freely relative to the end members. Then the adjustment sleeves on one end member are slid to the upper end of such end member, whereas the corresponding sleeves of the opposite end member are slid to a lower end portion. Thereafter both end members can be drawn together in parallel relationship with the caster wheels of both end members at the same end of the collapsed unit. However, the caster wheels of one end member will project outwardly slightly beyond the caster wheels of the other end member when the length of platform member 16 equals the length of the end members, since the sleeve couplings 68 of one end member can never quite be moved to the extreme upper end of such member because of the curved nature of such end. This facilitates mobility of the scaffold in its collapsed condition because the outermost set of caster wheels can be placed on the ground surface and used to help propel the unit without interference from the other set of casters. If desired, a tie strap M34, as shown in FIG. 4, may be provided for locking the end members together to maintain the scaffold unit in a collapsed condition.

F IGS. 7 and 8. illustrate a modified scaffold structure incorporatingseveral features of the invention includinga modified remote brakingmechanism. The structure includes a pair of ladder ends 110, only one of which is shown, joined together by a platform cross member 112. Each ladder endincludes a pair of

upright leg members

113, 114 joined together by rungs 116. Vertical adjustability of the platform is achieved by inserting the opposite ends of a U-shaped rod118into one of several vertically spaced pairs of sleeves 120 fastened .to'the inside faces of

ladder legs

113, 114. Rod 118 is pivotally retained within a section of pipe 122 secured to anendof the platform by

straps

124, 125. g

A corner brace .126 extends between an intermediate side portion ofplatform 112 and lower-portions of ladder legs'l 13,

114 and are fastened to the ladder by boltsand wing nuts 1 28.

Thus,theladderendscanbe folded flatbeneath the platform for storage or transport after .cornerbraces 126 have beenunfastened fromtheir associated ladder legs.

Each of the ladder ends is mounted on a pair of swivel :casters 130, such including a wheel 513:1, swivel yoke 132 and fixed top plate 133 fastened to abase member 134 of the ladder end. A brake shoe 136 is moved intoand out of frictional engagementwith wheel l31by abrake arm 138 which extends through aligned openingsin base member 134, top plate 133 and yoke '132. Brake arm 138 iscoaxial with the swivel axis of the caster andthe brake shoe swivels on the arm so that the brake can be applied in allpositions of the cas'ter wheel. The upper end of brake arm 138 is attached to the outer end of a lever member 140 pivoted at 141 and connected to another lever member 142 at 143. One end 1440f lever 142 is connected tothe lower end of a verticalbrake rod 146. The upper end of rod 146 is connected to an eccentric portion of a brake-applying lever 148 pivoted at 14910 a bracket 150, which in turn is rigidly fastened to the upper end ofleg 114 of the ladderend.

With the foregoing arrangement the oaster brakes are released in the raised handle position of brake lever 148 shown in FIG. 8. l-lowever by pushing 'thelong'handlejportion of lever 148 down to raise rod 146 to an overcenter position with respect to pivot 149, lever 142 applies a downward braking force to the left-hand caster wheel of FIG. 7. At the same time lever 140 applies a brakingforce through arm 138 and shoe 136 totheright-hand caster wheel.

With reference to FIGS. 9 through 13 showing what is presently a preferred embodiment of the invention, the scaffold includes ladder ends 200, 202 and a platform 204 joined to the ladder ends at glide members 206. The glide members are slidable vertically along sidechannels 208 of the ladder ends for vertical adjustment of platform 204. Each glide member includes a glide lock 210 pivoted on the glide member. Referring to FIG. 13, the glide lock has a handle portion 211 and a locking pin portion 212. Locking pin 212 "extends through a slot 214 in the glide rnemberandthrough one of several spaced openings 216 in an inner flange 218 of ladder side channel 208 to lock the glide member and thus platform 204 to the ladder end. 4

Each glide member 206 is generally channel-shaped and sized to slidably engage one of the channel-shaped side members 208 of the associated ladder end. Each glide includes an inwardly extending flange portion'220 which mounts glide lock 2'10. Glide flange 220 also includes an upper edge slot 222 and a lower edgeslot 224, both of which are downwardly inclined from the free side edge of the glide flange. These slots are adapted to receive a laterally projecting rod end 226 of platform member 204, so as to provide a pivotal interconnection between the platform and the ladder ends. A plank lock plate 228 pivoted on the glide flange adjacent each

slot

222, 224 is adapted to lock the rod end withinone of the slots when the plate is pivoted to a position overlying the rod end as shown with respect to upper slot222. The platform lockplates also provide a quick release for disconnecting the platform from the ladder ends when desired.

Glide flange 220alsoincludes apair of

horiz'ontaledge slots

227, 229, the lower one of which receives a wing nut fastener 231 on the lower end of a platformbrac'e 230 forrigidifying the connectionbetween theladder ends and platform. The opposite end of each corner brace 230 is normally pivotally connected to a side of platform 204in the manner shown in FIG. 9.

- The two glide members 206 on opposite sidechannels 208 of the same ladder end 202 are joined together by

rods

232, 234 as shown in FIG. 10. These rods serve the dual function of llightweight yet strong construction'are aluminum orstainless steel. Platform 2'04'is also preferably of generally lightweight channel construction, including metal channel side members 240 joined together \byan overlying woodor metal plank 242 and therod ends 226. Reinforcing cross memberstnot shown) spaced at intervals betweenitheside channels 240 beneath the .plank reinforce the platform assembly.

Thescaffold of FlG. 9, like the scaffolds of FIGS. 1 and 7, is

.mounted on casters 244 provided with a suitable remote braking means. l-Ioweventhe braking means ofthe scaffold-of FIG. "9, shown in detail in 'FIG. 12, differs from the brakes of the previous embodiments in that it prevents swiveling moving of the caster as well as rotation of the caster wheel. With reference to FIG. 12, caster 244 includes a lower caster portion 246 which swivels relative to an upper caster portion 248 'tixed to the ladder basemernber 238 by fasteners 249uA king pin 250 concentric about the swivel axis of the lower caster portion joins the upper and lower caster portions together,

and ball bearings ,252 provide fora smooth,swiveling movement of the lower caster portion. Lower caster portion 246 includes a yoke 254-whichrotatablysupports a caster wheel 256 on axle 257. A brake shoe 258 is positioned between the opposite arms of yoke 254 and has opposite side flange portions 260 pivoted thereto at 259. The shoe is generally channelshaped and has a web portion 261 whichstraddles the caster wheel to serve as a braking surface engageable with the peripheral surface of the caster wheel upon clockwise pivoting movement of the brake shoe about its pivot axis. The shoe also includes an upwardly projecting, swivel-braking tooth portion 262 which is engageable with one of a series of downwardly projecting complementary teeth 264 at the periphery of the upper caster portion 248 upon clockwise pivoting movement of the brake shoe about its pivot axis. Thus clockwise pivoting movementof the shoe provides simultaneous braking of the caster wheel and of the lower swiveling portion of the caster.

Braking force is applied to the brake shoe by a plungerpin 266 which extends through an axial opening 267 in kingpin 250 and into engagement-at itslower end with web 261 of the brake shoe. The upper end of the plunger pin engages a plunger pin actuator 268 pivoted at 269 to a plunger bracket 270 fixed to the top of ladder base 238. One end of a brake cable 272 is attachedlat 273 to the actuator 268 and extends around a pulley wheel 274. Cable 272 is connected at it'soppositeend (not shown) to a similar brake actuator for the opposite caster wheel of the same ladder end. Cable 272 is connected at275 to a primary brake applicator cable 276 which extends upwardly to a brake applicator lever similar to the lever 62 disclosed in FIG. 5 with respect to embodiment of FIG. 1, near the upper end of the ladder assembly. Thus the applicationof a pulling force to the main cable 276 applies the brakes of both caster wheels on the same ladder end, and simultaneously prevents both rotation of the casterwheels and swiveling movement of the casters. FIG. 10 illustrates a manner of converting the scaffold ladder of FIG. 9 to a trestle ladder. For this conversion the platform is removed from between the ladder ends by releasing the corner braces 230 and platform rods 226 from engage ment with the glide flanges. The upper inner edges of the ladder ends are provided wifhTnating halves of butt hinges 278 which are then brought into mating relationship with one 7 another to connect together the upper ends of the ladders by inserting the hinge pins. Glides 206 are slid to the lower ends of the ladders, and two of the platform braces 230 are used in the manner shown to connect together and brace the lower ends of the ladders at a spacing corresponding to the length of the platform braces. Then, with the caster brakes applied, the resulting trestle ladder can be maintained in a predetermined position. With the brakes released, the trestle ladder can be wheeled from place to place as desired.

FIG. 11 shows the scaffold ladder of FIG. 9 in a fully collapsed condition for portability. This condition is achieved with reference to F168. 9 and 11 by releasing the platform braces 230 from either the platform or the glide flanges, placing the platform rod 226 at one end of the platform in the lower glide flange slots 224 on one ladder, and maintaining the opposite platform rod in the upper glide flange slots 222 of the opposite ladder. Then glides 206 of the last-mentioned ladder are moved to the extreme upper end of such ladder, and the glides of the first-mentioned ladder are moved to the extreme lower end of such ladder. This will draw the ladder ends together, and the ladder ends can be placed in a compact relationship with the platform 204 nested between the ladder ends and with all three of the main components in parallel relationship as shown in FlG. 11. In this position all four caster wheels engage the ground surface, and thus the collapsed ladder can easily be wheeled rather than carried to a new location.

Having illustrated and described several embodiments of the invention, it should be apparent to those having skill in the art that the same permits of modification in arrangement and detail. We claim as our invention'all such modifications as come within the true spirit and scope of the appended claims.

We claim:

1. A scaffold comprising:

a pair of upright opposite end members;

a horizontal cross member extending between said end members;

wheel means supporting each of said opposite end members on a supporting surface;

brake means for braking said wheel means; and

brake applying means on at least one of said end members at a position remote from said wheel means including linkage means extending from said applying means to said brake means, said applying means including a manually selectively operable brake-applying lever operable from said cross member to apply said brake means when moved in one direction and released and to release said brake means when moved in another direction and released.

2. Apparatus according to claim 1 wherein there are at least two of said wheel means, brake means for each wheel means and a single remote brake applying means for activating both said brake means.

3. Apparatus according to claim 1 wherein said wheel means includes a swiveling type caster.

4. Apparatus according to claim 1 wherein said wheel means includes caster wheel means swivelable about an upright axis, said brake means includes a brake shoe for frictionally engaging said caster wheel means, and said brake applying means includes means for transmitting a braking force to said shoe along the axis of rotation of said caster wheel means, whereby said brake means can be applied from a remote source in any rotational position of said caster wheel means.

5. Apparatus according to claim 1 wherein said brake applying means includes a manually actuated overcenter lever near an upper end portion of at least one of said upright end members.

6. Apparatus according to claim 1 including tubular means on said end members and cooperative means on the opposite ends of said cross member releasably interconnectable with said tubular means for effecting vertical adjustment of th height of said cross member.

7. Apparatus according to claim 1 including connector means connected to said cross member'and selectively slidable vertically on said end members for adjusting the height of said cross member relative to the bottom of said end members.

8. Apparatus according to claim 7 wherein said connector means includes slide means slidable along said end members and means pivotally interconnecting said cross member and said slide means for relative rotation of said end members and cross member about a horizontal axis whereby said scaffold can be folded into a relatively flat, compact unit with said end members and cross members lying substantially parallel and contiguous with'one another.

9. Apparatus according to claim 8 wherein said end members include rungs so as to comprise ladder ends, said pivotally interconnecting means including quick-disconnect means for separating said cross member from said ladder ends whereby with said brake means applied said ladder ends can be used separately as straight ladders.

10. Apparatus according to claim 8 wherein said end members include rungs so as to comprise ladder ends, said pivotally interconnecting means including quick-disconnect means for separating at least one of said end members from said cross member, and adjustable brace means for interconnecting the other said end member and said cross member below the pivoted connection between said last-mentioned members and with said last-mentioned members in angular relation with one another whereby said last-mentioned members can serve as a step ladder.

11. Apparatus according to claim 1 including means pivotally interconnecting said end members and said cross member and releasable corner brace means extending diagonally between said cross member and each end member providing a relatively rigid interconnection of said end members and cross member to an extent such that said cross member and said corner brace means comprise the sole means of vertical support for said end members.

12. Apparatus according to claim 7 including locking means supported by said connector means and selectively engageable with said end members at different elevations on said end members for locking said cross member at selected elevations on said end members.

13. Apparatus according to claim 12 wherein said locking means includes means pivotal about a horizontal axis relative to said end members and pin means engageable with pin receiving openings in said end members, said pin means and pivotal means being interrelated to said end members in a manner such that downward force applied to said cross member increases the locking engagement of said pin means within said opening, and upward sliding movement of said connector means relative to said side members releases said pin means from locking engagement with said opening.

14. Apparatus according to claim 8 wherein said end members include rungs to comprise ladder ends, quick-disconnect means for separating said cross member from said ladder ends, means at the upper ends of said ladder ends for hingedly connecting said upper ends, and brace means for tying together the lower ends of said ladder ends in spaced relationship for converting said scaffold to a trestle ladder.

15. A scaffold comprising:

a pair of upright opposite end members;

a cross member extending between said end members and defining a platform;

rung means on at least one end member providing a ladder for ascending to said platform;

connector means connecting said cross member to said opposite end members; and

said connector means including means slidable along said end members for adjusting the height of said cross member.

16. Apparatus according to claim 15 wherein said connector means includes means pivotally interconnecting said cross member and said end members.

17. Apparatus according to claim 15 wherein said end members each include a pair of laterally spaced apart channelshaped side members joined by ladder rung means;

each side member including an inner and an outer flange with said inner flange being provided with longitudinally spaced lock-receiving openings; said slidable means including a channel-shaped glide member slidable along each channel-shaped side member; and

pivotable locking means on each glide member selectively engageable with said inner flanges within said lockreceiving openings.

18. Apparatus according to claim v4 wherein said brake means includes means for preventing swiveling movement of said caster wheel means upon application of said braking force.

19; Apparatus according to claim 4 whereineach said caster wheel means includes an upper caster portion fixed to one of said end members and a lower caster portion normally capable of swiveling movement relative to said upper portion and carrying a caster wheel and said brake shoe, said shoe being movable into braking contact with both said upper caster portion and said wheel upon application of said braking force to prevent both rotation of said wheel and swiveling of said lower caster portion.

20. Apparatus according to claim 17 wherein said glide member includes quick disconnect means for connecting and disconnecting said cross member from said glide member.

21. A scaffold comprising:

a pair of upright end members with at least one of said end members comprising a ladder end;

a cross member adapted to extend generally horizontally between said end members to serve as a walkway;

pivotal connector means on opposite ends of said cross member and on said end members for pivotally interconnecting said cross member and said end members at various positions of adjustment along said end members;

diagonal brace means extending between said cross member and said end members for selectively rigidifying the inner connection of said cross member and said end members with said end members in their upright position and said cross member extending horizontally; and

said pivotal connector means including quick disconnecting means for separating at least one end member to enable quick separation and connection. of said cross member with said end members to enable use of said ladder end as a single ladder and for enabling use of said ladder end and one cross member and their associated diagonal brace means as a stepladder.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 2,

Anthony T. Fredricks and Paul F. Smith It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the addresses for the inventors, Iowa" should be Idaho--.

Signed and sealed this 1 0th day of August 1 971 (SEAL) Attest:

EDWARD M.FLETGHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents a FORM PQAOSD (10-65)

Claims

1. A scaffold comprising: a pair of upright opposite end members; a horizontal cross member extending between said end members; wheel means supporting each of said opposite end members on a supporting surface; brake means for braking said wheel means; and brake applying means on at least one of said end members at a position remote from said wheel means including linkage means extending from said applying means to said brake means, said applying means including a manually selectively operable brakeapplying lever operable from said cross member to apply said brake means when moved in one direction and released and to release said brake means when moved in another direction and released.

6. Apparatus according to claim 1 including tubular means on said end members and cooperative means on the opposite ends of said cross member releasably interconnectable with said tubular means for effecting vertical adjustment of the height of said cross member.

7. Apparatus according to claim 1 including connector means connected to said cross member and selectively slidable vertically on said end members for adjusting the height of said cross member relative to the bottom of said end members.

8. Apparatus according to claim 7 wherein said connector means includes slide means slidable along said end members and means pivotally interconnecting said cross member and said slide means for relative rotation of said end members and cross member about a horizontal axis whereby said scaffold can be folded into a relatively flat, compact unit with said end members and cross members lying substantially parallel and contiguous with one another.

15. A scaffold comprising: a pair of upright opposite end members; a cross member extending between said end members and defining a platform; rung means on at least one end member providing a ladder for ascending to said platform; connector means connecting said cross member to said opposite end members; and said connector means including means slidable along said end members for adjusting the height of said cross member.

17. Apparatus according to claim 15 wherein said end members each include a pair of laterally spaced apart channel-shaped side members joined by ladder rung means; each side member including an inner and an outer flange with said inner flange being provided with longitudinally spaced lock-receiving openings; said slidable means including a channel-shaped glide member slidable along each channel-shaped side member; and pivotable locking means on each glide member selectively engageable with said inner flanges within said lock-receiving openings.

18. Apparatus according to claim 4 wherein said brake means includes means for preventing swiveling movement of said caster wheel means upon application of said braking force.

19. Apparatus according to claim 4 wherein each said caster wheel means includes an upper caster portion fixed to one of said end members and a lower caster portion normally capable of swiveling movement relative to said upper portion and carrying a caster wheel and said brake shoe, said shoe being movable into braking contact with both said upper caster portion and said wheel upon application of said braking force to prevent both rotation of said wheel and swiveling of said lower caster portion.

21. A scaffold comprising: a pair of upright end members with at least one of said end members comprising a ladder end; a cross member adapted to extend generally horizontally between said end members to serve as a walkway; pivotal connector means on opposite ends of said cross member and on said end members for pivotally interconnecting said cross member and said end members at various positions of adjustment along said end members; diagonal brace means extending between said cross member and said end members for selectively rigidifying the inner connection of said cross member and said end members with said end members in their upright position and said cross member extending horizontally; and said pivotal connector means including quick disconnecting means for separating at least one end member to enable quick separation and connection of said cross member with said end members to enable use of said ladder end as a single ladder and for enabling use of said ladder end and one cross member and their associated diagonal brace means as a stepladder.