US2762659A - Extensible scaffold - Google Patents

Description

Sept. 11, 1956 Filed March 16, 1953 C. A. HARLAN ET AL EXTENSIBLE SCAF'FOLD 4 Sneaks-Sheet 2 l6 INVENTORS CAMPBEtL ALLEN HARLAN y JOHN M.HAR.LAN

ATTORNEYS C. A. HARLAN ET AL EXTENSIBLE SCAFFOLD Sept. 11, 1956 4 Sheets-Sheet 3 Filed March 16, 1953 3 JOHN M.HARLAN "2% ATTORNEYS FIG.6.

Sept. 11, 1956 c. A. HARLAN ET AL 2,7

EXTENSIBLE SCAFFOLD Filed March 16, 1953 4 Sheets-Shet 4 IN V EN TORS CAMPBELL ALLEN HA R L AN 8 JOHN M.HARLAN Y W ATTORNEYS United States Patent EXTENSTBLE SGAFFOLD Campbell Allen Harlan, Birmingham, and John M. Harlan, Detroit, Mich.

Application March 16, 1953, Serial No. 342,666

12 Claims. (Cl. 304-29) The present invention relates to an extensible scaffold, and more particularly, an estensible scaffold including an extensible trackway mounting a vertically movable carrrage.

It is an object of the present invention to provide an estensible scaffold capable of being lowered to permit its passage through doors or the like, and capable of being extended to provide a working platform at a substantial elevation.

It is a further object of the present invention to provide an estensible scafiold characterized by its lightness, its ease and mobility, and its collapsibility,

It is a further object of the present invention to provide a readily movable extensible scaffold including power means associated therewith for raising and lowering the scaffold and for raising and lowering a carriage on the scaffold while the scaffold is either extended or collapsed.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of the extensible scaffold.

Figure 2 is a front elevation of the scaffold with parts broken away and parts omitted.

Figure 3 is a fragmentary section on the line 3-3, Figure 2.

Figure 4 is a section on the line 4-4, Figure 2..

Figure 5 is an enlarged fragmentary section on the line 55, Figure 3.

Figure 6 is an end view of the detail shown in Figure 5, looking in the direction of the arrows 66, Figure 5.

Figure 7 is an enlarged fragmentary section on the line 7-7, Figure 2.

Figure 8 is an enlarged fragmentary section on the line 8-8, Figure 2.

Figure 9 is an enlarged fragmentary section on the line 9-9, Figure 2.

Figure 10 is an enlarged line 1010, Figure 2.

Figure 11 is a fragmentary side elevation showing a modification of the scaffold.

Figure 12 is an enlarged fragmentary side elevation illustrating yet another modification of the scaffold.

Figure 13 is an enlarged fragmentary section on the line 1313, Figure 4.

Figure 14 is a View similar to Figure 13 showing the relationship of parts after partial rotation of the drum.

Referring now to the drawings, the extensible scaffold comprises a lower frame indicated generally at 10 comprising vertically extending rear corner posts in the form of angle irons 12, and vertically extending front corner posts in the form of angle irons 14. The lower ends of the angle irons 12 and 14 are interconnected by side frame members 16 and end frame members 18. The angle irons 12 and 14 are disposed with their flanges extending parallel to the sides and ends of the frame and with the concave portion thereof facing inwardly of the frame. At the tops of the angle irons 12 and 14 there fragmentary section on the structure.

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are provided a pair of side frame members 20 and the rear corner posts 12 are interconnected by a cross frame member 22. The upper ends of the front posts 14 are not directly interconnected, since this space is required for movement of a vertically movable frame construction indicated generally at 24. The lower or main frame 10 however, is braced by suitable means such for example as the diagonally extending brace rods some of which are designated at 26.

In order to provide easy movement of the scaffold from place to place, the main frame 10 is provided with casters 28.

The vertically movable frame 24 .is telescoped within the main frame 10 and comprises rear corner posts 30 and front corner posts 32. The corner posts 30 and 32 are in the form of angle irons which are nested within the angle irons comprising the corner posts 12 and 14 of the main frame.

Inasmuch as the vertically movable frame 24 moves freely within the main frame 10, its rear corner posts 24 and front corner posts 32 are interconnected at their bottoms by longitudinally extending angle irons 34 and laterally or transversely extending angle irons 36. At the same time the upper ends of the corner posts of the movable frame 24 are interconnected by longitudinally extending angle irons 38. The rear corner posts 30 are interconnected by an angle iron 40. The forward portions of the longitudinally extending angle irons 38 are interconnected by a transverse angle iron 42. In addition, a second angle iron 44 interconnects the front corner posts 32 intermediate their ends by means of brackets 45 as well illustrated in Figure 9. As in the case of the main frame 10, the movable frame 24 is rendered rigid by diagonally extending brace members some of which are designated at 46.

A carriage, generally indicated at 50, is provided which is mounted for vertical movement on the scaffold from top to bottom thereof whether or not the scaffold is in vertically extended or collapsed position. The carriage 50 comprises a pair of substantially vertically extending laterally spaced angle irons 52 interconnected at their tops and bottoms by angle irons 54 to produce a rigid The space between the vertical angle irons 52 and the horizontal angle irons 54 is covered by a panel 55. Pivoted adjacent the upper ends of the angle irons 52 is a platform 56, the hinge connection being indicated at 58. In order to maintain the platform 56 in proper position, suitable braces 60 are provided, which as illustrated in Figure l rigidly support the platform 56 in horizontal position.

In order to provide for substantial movement of the carriage 50 in any position of adjustment of the scaffold, rearwardly extending brackets 62 and 64 are provided having openings therein forming journals for shafts 66 on which are mounted wheels or rollers 68. A pair of rollers 68 are mounted adjacent the lower corners of the panel 55 and a second pair of such rollers are mounted adjacent the sides of the panel intermediate the upper and lower edges thereof, as best illustrated in Figure 3.

Carried by the vertical posts 14 at the front of the main frame 10 are a pair of vertically extending roller receiving tracks 70. Carried adjacent the front posts 32 of the movable frame 24 is a second pair of roller receiving tracks 72. Each of the tracks, as well illustrated in Figure 8, includes a straight inwardly extending flange 74, an outer wall 75, and an arcuately curved forward wall 76, these being adapted to partly surround the corresponding roller 68 as illustrated in Figure 5, so as to prevent removal of the roller from its track except through an open end thereof.

The stationary tracks 70 are connected to the posts 14 by a plurality of brackets 80 as illustrated in Figure 7, which are bolted or otherwise secured to the inwardly extending flange of the posts14 by bolts 82', and are bolted to the wall 75 of the tracks 70 by bolts 84. It will be observed that the-heads of the bolts 84 are countersunk to avoid interference with movement of the rollers in the tracks. Adjacent the upper end of the main frame 10, as best illustrated in Figure 9, there are provided brackets -36 which interconnect the posts 14 and the tracks 70. The bracket 86 provides a web 88 secured to the track 70 by means of rivets 90, these rivets also serving to secure a pair of bracket members 92 in position, the bracket members 92 being separated at their upper ends as illustrated in Figures 1 and 2 to provide openings forming journals for sheaves 94. The track members 72 are secured to and vertically movable with the movable frame 24.

As best illustrated in Figure 8, the movable frame 24 is provided with the angle iron 36 extending transversely across and interconnecting the forward portions of the longitudinally extending angle irons 34. The vertically movable tracks 72 are connected adjacent their bottoms to the angle irons 36 by suitable means such as the rivets indicated at 96.

As best seen in Figure 9, the cross piece 44 is riveted or otherwise secured as indicated at 100, to the mid-portion of the trackway 72, the ends of the angle iron or cross piece 44 being connected to the longitudinally extending flanges 98 of the front corner posts 32 by the brackets 45. As best seen in Figure 1, the cross piece or angle iron 42 may also be similarly connected to the upper ends of the tracks 72.

It will be recalled that the front posts 14 of the main frame are not directly interconnected at their upper portions and this of course is for the purpose of permitting passage therethrough of the means which serve to interconnect the movable frame 24 and the carriage 50. However, a construction is provided which supports the upper ends of the posts 14 against lateral displacement and this construction is best illustrated in Figure 9. As seen in this figure, the stationary front corner posts 14 of the main frame comprise the rearwardly or longitudinally extending flanges 103, and inwardly or transversely extending flanges 104. The bracket 86 which connects the angle iron 14 to the stationary track sections 70 carries a spacer block 106 to which is secured a plate 108, suitable securing means such as the bolt 110 being provided. it will be observed that the stationary corner post 14, the bracket 86, the spacer block 106, andthe plate 108 together provide surfaces which confront portions of the vertically movable corner post 32 in four directions. The corner post 32 comprises the rearwardly or longitudinally extending flange 98 and an inwardly or laterally extending flange 114. More specifically, the inner surface of the rearwardly extending flange 103 confronts or engages the outer surface of the rearwardly or longitudinally extending flange 98 of the corner post 32. The rearwardly facing surface of the flange 104 of the corner post 14 engages or confronts the forwardly facing surface of the inwardly extending flange 114 of the corner post 32. The spacer block 106 engages or confronts the end surface of the flange 114. The forwardly facing surface of the plate 108 engages or confronts the rearwardly directed surface of the flange 114. The outer edge of the plate 108 engages or confronts the inner surface of the rearwardly extending flange 98 of the post 32.

It will be recalled that the corner posts 32 are rigidly interconnected at their tops, bottoms and mid-portions by cross members. From the foregoing it will be apparent that the rigid interconnection between the corner posts 32 of the movable frame 24 thus provides an adequate support for the upper portions of the corner posts 14 of the main frame 10.

As well illustrated in Figures 8 and 9, the track sec tions and 72 are directly adjacent to each other and are so spaced that each receives one of the rollers 68 carried by each of the brackets 62. Thus, when the movable frame 24 is in its lower or collapsed position, each of the rollers 68 is engageable in a pair of adjacent tracks 70 or 72. However, when the movable frame 24 is elevated to its uppermost position it is possible to elevate the carriage 50 to the position illustrated in Figure 1 and still maintain adequate support therefor. At this time the sets of rollers 68 most closely adjacent to the carriage 50 move out of the open upper ends of the tracks 70 but the outermost of the pairs of rollers remains in the tracks 72. Thus, at all times at least four rollers are engaged in trackways so as to provide adequate support for the carriage.

As best seen in Figure 11, means may be provided for mounting a hopper on the vertically movable carriage 50. In this case the upper ends of the upper track 72 include an arcuate portion 122 and as the carriage 50 reaches the upper end of the track 72 it enters upon the arcuately curved portion 122, thus tipping the hopper to the position illustrated in Figure 11. It will of course be appreciated that the curved portions 122 of the track 72 may be caused to tip either forwardly or rearwardly. In the case where the covered portions of the track tip forwardly, the hopper may be caused to dump into a receptacle located in front of the scaffold. In Figure 11 however, the tracks are illustrated as curved rearwardly and there is shown a receptacle 124 which will be carried at the top of the movable frame 24, into which the contents of the hopper 120 may be dumped.

Referring now to Figure 12 there is illustrated another variation of the present invention, in which case the carriage 50 is provided with a lower platform 126 held in position by supporting arms 123. Spaced upwardly from the platform 126 is a railing 130 which will provide a safety feature for a man standing upon the platform 126. If desired, a section of the railing 130 may be movably associated with the remainder of the railing to permit ready access to the platform, after which the movable section of the railing may be replaced. Conveniently, the movable section of the railing may be hinged at one end to the carriage and have a releasable locking engagement at its free end with the remaining portion of the railing.

Power means are provided for selectively raising and lowering the movable frame 24 relative to the main frame 10, and for selectively raising and lowering the carriage 50.

As best illustrated in Figures l4, the means for raising and lowering the movable frame 24 comprises a pair of cable Winding drums 132 carried on a shaft 134, mounted in suitable bearings indicated at 136 which are carried by the longitudinally extending main frame members 16. Sheaves 138 are provided adjacent the lower rear corners of the main frame and sheaves 140 are provided adjacent the upper rear corners of the main framev In like manner, sheaves 142 are mounted adjacent the lower front corners of the main frame, and sheaves 94 previously referred to are carried by the main frame adjacent the top front corners thereof. A pair of cables 144 are provided each associated with one of the drums 132 and the sheaves 138, 140, 142 and 94. One end of each of the cables 144 is secured to the lower portion of the movable frame 24 as indicated'at 146 in Figure 1, and the opposite end of each of the cables is secured to a corresponding point at the forward ends of the movable frame 24 as indicated at 148 (Figure 2 and 3).

Reference is now made to Figure 13 to illustrate a useful modification of the cable winding drums 132. Each of the drums as illustrated in Figure 13 is provided with a radially extending flange 150 at one end thereof and these flanges 150 are in turn provided with diametrically opposite outwardly opening cable receiving notches 152. The cable 144 is initially connected over the sheaves and secured at its ends to the lower corners of the movable frame 24 as previously described, in such a way as to leave a certain amount of slack or looseness in the cable. This permits producing a bight in an intermediate portion of the cable adjacent one of the drums 132 and the cable is introduced through the notches 152 as illustrated in Figure 13 so that the bight of the cable, indicated at 154, is located outwardly of the drum by the flange 150, and the leads of the cable 144 extending away from the drum are located to overlie the drum. With the parts in the relationship illustrated in Figure 13, 180 rotation of the drum and flange brings the leads of the cable 144 into engagement with the periphery of the the drum and further rotation winds up both leads of the cable simultaneously. The foregoing construction is highly desirable in that it permits ready separation of the cable from the main frame without disengaging its ends from their securement to the movable frame.

The shaft 134, as best illustrated in Figure 4, is provided with a combined pulley and brake member 160 and is connected by a pulley belt 162 to a driving pulley 164 mounted on a drive shaft 166. Suitably associated with the brake drum 168 is a brake diagrammatically indicated at 170 which is adapted to lock the brake and hence the shaft 134 against rotation. An electric motor 172 is mounted on the main frame and includes a worm 174 meshing with a worm wheel 176 keyed or otherwise secured to the shaft 166. The pulley 164 is axially movable on the shaft 166 between a first position in which it is splined to the shaft and hence rotatable therewith, to a second position in which it is freely rotatable on the shaft. Suitable means for effecting driving engagement between the pulley 164 and the shaft 166 are well known and are not illustrated or described in detail at this point. From the foregoing it will be observed that when the driving pulley 164 is in position to be driven by the shaft 166, rotation is imparted to the shaft 134 and hence the cable winding drums 132 will be driven in one direction or the other depending upon the direction of rotation of the motor 172, thus raising or lowering the movable frame 24.

Rigidly secured at all times to the shaft 166 is a second cable winding drum 177 to which is secured a cable 178 movable around a sheave 180 carried by the cross bar 18 at the lower end of the main frame 10, and thence upwardly over a sheave 182, the end of the cable 178 being connected to an intermediate point of the cross bar 54 of the carriage 50. Thus, when the motor is actuated the carriage 50 may be raised or lowered in accordance with the direction of actuation of the motor.

With the foregoing detailed description in mind, it will be observed that by suitable actuation of the motor the movable frame 24 may be raised and lowered and may be locked in any desired elevated position by engagement of the brake 170. Moreover, the carriage 50 may be selectively raised or lowered from a lowermost position to an elevated position determined by the amount of elevation of the movable frame 24.

It will be observed in Figure 1 that the platform 56 of the carriage 50 is located substantially above the top of the movable frame 24. This is a very desirable feature since it permits locking of the movable frame 24 in a position such that it will clear overhead structure in a building for ready movement thereon, and at the same time permits elevation of material on the platform 56 to a point substantially above the top of the movable frame 24.

The drawings and the foregoing specification constitute a description of the improved extensible scaffold in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the'invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. An extensible scaffold comprising a lower frame having a first pair of vertically extending tracks carried by said lower frame at the front thereof, a movable frame guided for vertical movement on second pair of vertically extending tracks carried by said movable frame at the front thereof, each track of said second pair being parallel to, laterally spaced from and in proximity to one of said first pair of tracks, a vertically movable carriage at the front of said scaffold and having at each side thereof a vertically spaced pair of guide devices, each of which comprises a pair of elements, corresponding elements of each of said pair of elements being vertically movable in and guided by one of said first pair of tracks and the other element of each pair of elements being vertically movable in and guided by one of said second pair of tracks.

2. An extensible scaffold as defined in claim 1 in which said movable frame is telescoped within said lower frame.

3. An extensible scaffold as defined in claim 1 in which said tracks comprise channel members and said elements comprise rollers.

4. An extensible scaffold as defined in claim 3 in which said channel members are shaped to surround said rollers to an extent sufficient to prevent movement of said rollers laterally out of said channels.

5. An extensible scaffold as defined in claim 1 comprising a motor on said lower frame, and lift means operated by said motor for selectively raising said movable frame and said carriage.

6. An extensible scaffold as defined in claim 5, said lift means comprising drum and cable means for raising and lowering said carriage, a connection between said motor and drum means, a second drum and cable means for raising and lowering said movable frame, and means for selectively connecting and disconnecting said motor and second drum means.

7. An extensible scaffold as defined in claim 4 in which each of said pairs of tracks are disposed with the open side of the channel members in confronting relation, and the tracks of the pair carried by said movable frame are positioned directly in rear of the tracks of the pair carried by said lower frame.

8. An extensible scaffold as defined in claim 1 in which said carriage includes a paltform and a platform support extending downwardly therefrom, the uppermost of said pair of guide devices at each side of said carriage being disposed substantially below said platform to provide for elevation of said platform above the top of said movable frame.

9. An extensible scaffold comprising a redtangular lower frame elongated from front to rear and having a pair of front and a pair of rear corner posts, means interconnecting the tops and bottoms of said rear posts, means interconnecting the top and bottom of each rear post with the top and bottom of the corresponding front corner post, means interconnecting the bottoms of said front posts, the space between said front corner posts upwardly from the bottoms thereof being unobstructed, a movable frame guided for vertical movement within said lower frame and having front and rear corner posts guided for vertical movement by the corresponding corner posts of said lower frame, means interconnecting the tops and bottoms of each corner post of said movable frame to the tops and bottoms of the adjacent corner posts thereof, means carried by the front corner posts of one of said frames slidably engaging the front corner posts of said other frame to prevent separation between the upper portions of the front posts of said lower frame, a first pair of vertically extending tracks on said lower frame, each of which is adjacent to and carried by a front corner post thereof, a second pair of vertically extending tracks on said movable frame, each of which is adjacent to and carried by a front corner post thereof parallel to but spaced laterally from the track carried by the adjacent front corner post of said lower frame, a vertically movable carriage having at each side thereof a pair of vertically spaced guide devices, each guide device comprising a pair of elements, one of which is received by a track said lower frame, a

carried by said lower frame and the other of which is received in a track carried by said movable frame.

10. A scaffold as defined in claim 9 in Which each pair of tracks comprises channel members disposed with the open sides thereof in confronting relation, and in which said elements comprise rollers received in the channels of saidv channel members.

11. A scatfold as defined in claim 10 in which the tracks of said firstpair of tracks are positioned in front of the tracks of said second pair. of. tracks.

12. A scaffold as defined in claim 10, the upper ends of said first pair of tracks being open to provide for movement. of the rollers out of. the upper end thereof upon upward movement of said carriage while said movable frame is in elevated position.

References Cited in file of this patent UNITED STATES PATENTS Dye Mar. 11, 1884 Miller Nov. 23, 1920 Green Apr. 24, 1928 Artini Apr. 23, 1940 Eypper Oct. 28, 1947 Moon Aug. 28, 1951 Boedecker et al. Oct. 2', 1951 Campbell Mar. 11, 1952 Segal July 14, 1953 Badik et al. Aug. 18, 1953

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