US2846275A - Adjustable scaffolding - Google Patents

Description

Aug. 5, 195s G. H. ESCH 2,846,275

ADJUSTABLE SCAFFOLDING Filed Aug. 23, 1955 4 Sheets-Sheet 1 ATTURNEXS.'

Aug- 5, 1958 G. H. Escl-l 2,846,275

ADJUSTABLE SCAFFOLDING Filed Aug. 23, 1955 y 4 Sheets-Sheet 2 R H '94 M Il I I: l l

ATTRNEYS.

u lyv mb MN v Aug. 5, 1958 l G. H. EscH ADJUSTABLE SGAFFOLDING Filed Aug. 23,v 1955 4 Sheets-Sheet 3 E l I INVENTOR:

BY m,

wm v Ww ATTORNEY Aug. 5, 1958 G. H. EscH 2,846,275

ADJUSTABLE SCAFFOLDING y Filed Aug. 23. 1955 4 sheets-sheet 4 IN V EN TOR.

ATTaRNEY 2,846,275 ADJUSTABLE SCAFFOLDING George H. Esch, Dearborn, Mich., assignor to A. B.

Segur, doing business as A. B. Segur and Company,

Oak Park, Ill.

Application August 23, 1955, Serial No. 529,996 13 Claims. (Cl. 304-29) This invention relates to scaffolding, and more specically to an adjustable scaffolding which may be adjusted both vertically and horizontally and which, therefore, may be easily adapted to the structural characteristics of any particular work project.

While various types of adjustable scaiords are known in the art, these scaiords all generally require the erection of vertical towers at the place where construction, maintenance or repair work is to commence. Where the Work space is confined or enclosed, or where other equipment is present in the area, the erection of such towers is often exceedingly diicult, if not impossible. Often, the component parts' of the tower frame are too large or bulky to be assembled within the confined space, and the entrance to the enclosure is too small to permit an assembled tower to be moved into the area from the outside.

Furthermore, present scaffold structures are not well adapted for supporting workers and materials where irregular or sloping surfaces are to be repaired or constructed. For example, the back walls of open hearth furnaces generally slope outwardly at angles of approximately 45. It is apparent that a scaffold structure must accommodate this slope in order to permit building or repair operations at different elevations along the walls. However, the conventional tower construction of present scaifords makes them generally unsuitable for these purposes.

Another shortcoming of present scatolds is the great expenditure of time and expense which is often necessary to erect and remove these structures. Where the structure to be built or repaired has an irregular or inclined surface, any scaffold which is constructed in the conventional manner is invariably complex and requires considerable time, labor and expense to complete, and later to dismantle,

Therefore, one of the main objects of the present invention is to provide an adjustable scaffolding which overcomes the defects of the present scaffold structures, and especially the disadvantages mentioned above. Another object is to provide a scaffolding which may easily be adjusted either horizontally or vertically, or

both. A further object of my invention is to provide a r scaffolding which can be litted into a variety of enclosed or confined spaces, and which may be adjusted to conform to the irregular or sloping surfaces of any particular structure.

An additional object is to provide a power operated scaffolding having a horizontal platform assembly which is vertically adjustable, and which will remain level even whenthe elevation of the platform is being changed. A still further object is to provide a scaffolding having a vertically adjustable platform assembly which will securely lock itself in position should the driving means for elevating and lowering the platform assembly become inoperative.

Other objects and purposes will appear from the specification and drawings, in which:

Figure l is a broken side elevational showing a scaffold embodying the present invention; Figure 2 is a cross sectional view of one of the columns shown in Figure l, and taken along line 2--2 of Figure 1; Figure 3 is a broken sectional side View of a column taken along line 3--3 of Figure 2; Figure 4 is a broken top plan View of ICC the adjustable platform assembly of the present invention; Figure 5 is a broken sectional side view of the platform assembly taken along line 5-5 of Figure 4 and showing the assembly in one of its operative positions; Figure 6 is a broken sectional side view similar to Figure 5, but showing the platform assembly in another operative position; Figure 7 is a broken top sectional View showing details of construction of the platform and column assembly and is taken along line 7-7 of Figure 6; and Figure 8 is a partly diagrammatic View illustrating the power or driving means for the present invention.

My scaffolding consists essentially of a plurality of vertical columns or posts 10 and an adjustable platform assembly designated generally by the numeral 1l. As shown in Figure 3, each of the vertical columns is preferably composed of a series of relatively short interlocking sections or segments 12. So that each of these segments furnishes a maximum amount of structural strength for its weight, I prefer to form each of them from a pair of U-shaped channel members 13 and 14, although it will be understood that these columns may be constructed in any other suitable manner. Between these channels, and welded or otherwise suitably secured thereto, are a plurality of spacer bars 15 which maintain the channel members in spaced apart and parallel relation. In the illustrations given, these spacer bars join the back sides of the channel members, and are uniformly spaced along at least one side of each of the column segments to provide a plurality of lugs or steps. It will also be seen that the bars 15 and channel members 13 and 14 define a socket 16 at one end of each column section 12. The opposite ends of all sections, except the lowermost sections of the vertical columns, carry plugs 17 which are adapted to be inserted into the sockets 16. While I prefer to weld the plugs to the ends of the segments 12, it will be apparent that these plugs might also be formed integrally with the column segments or sections.

From the foregoing, it will be seen that each of the vertical columns 10 is composed of a series of independent column segments 12 which are tted or locked together by means of sockets 16 and plugs 17. It is desirable that each of the interlocking segments be relatively short so that they may be easily handled andl managed during the erection of a scaffolding. kWhile the length of these segments may be varied considerably, depending uponv the nature and amount of material used in their construction and the space limitations of the paritcular working area, I have found that sections ranging from three feet to six feet in length are suitable for most purposes.

As shown in Figure l, the lowermost column segment 12 of each vertical column is provided with a shoe 18 for supporting and stabilizing the scaffolding upon any level surface. Further stability and rigidity of the scaffolding may be achieved by providing the interlocking segments with openings 19 and attaching cross braces 20 thereby by means of bolts or pins 21.

The platform assembly 11 is movablyr mounted upon the vertical columns 10 and includes a pair of horizontal frames 22 and 23 which are vertically spaced from each other, and which are independently connected to the columns. Figure 4 shows the upper frame 22 composed of two pair of parallel vand longitudinally extending beams 24 and 25 joined by corner plates 26, 27, 2Sv and 29 to two pair of parallel and transversely extending beams 30 and 31, and by plates 32 and 33 to'a pair of intermediate transverse beams 34. Most desirably, the longitudinally extending beams 24 and 25 of the top frame 22 are segmented and the adjacent ends of these segments are spaced apart by connecting plates 32 and 33 to permit horizontal adjustment of that frame, as will appear shortly. The connecting plates are preferably welded upon the top and bottom surfaces of the longitudinally extending beams, and are detachably connected to the transversely extending beams by bolts 3S or other suitable means. Figure 4 also shows the corner plates 26, 27, 28 and 29 apertured to receive the vertical columns or posts 10.

The lower frame 23 is identical to the upper frame 22 in all of the structural aspects already mentioned. In addition, both 'the upper and lower frames are provided with a plurality of pivotally mounted dogs or latches 36 which are adapted to engage the steps of each of the columns. As shown best in Figures 5, 6 and 7, each of the dogs 36 has a downwardly extending leg portion and a lever portion 33 lturned inwardly at substantially right angles to the leg po-rtion. A horizontal sleeve 39 is joined to or formed integrally with each of the dogs 36, and is secured to the rod 44E. Each rod or shaft 40 extends between a pair of adjacent beams and is rotatably attached thereto. As shown best in Figure 5, the pivotally mounted dogs, if permitted to swing freely, tend to pivot into engagement with the steps or lugs of the vertical columns because of the counter-balancing effect produced by the lever portions 3S. The ends of legs 37 are preferably notched to fit snugly upon each of the column steps 15.

All of the beams of the upper and lower frames have generally C-shaped cross sections, and the paired transversely extending beams carrying latches or dogs 36 are joined by C-shaped connecting members 4l adjacent each of the pivotally mounted dogs. These C-shaped connecting members have vertical slots 42 which receive the movable lever portions 38 of the dogs. As seen best in Figure 5, the legs of the C-shaped connecting members face inwardly and shelter electrical switches 43 which may be welded to the inner surfaces of those members. The switches are equipped with movable switching arms 44 in Contact with the lever portions 38 of the latches or dogsf36. Adjacent the outer surfaces of the connecting members 41 and above the lever arms of the dogs are solenoid coils 45 and 45a. These solenoids are carried within solenoid frames 46 which may in turn be connected to the connecting members by means of rivets 47. T he solenoid plungers 48 are preferably jointed and are connected to levers 38 of the dogs. Solenoid coils 45 and 45a are wound so that when 'they are energized, plungers 48 and levers 38 are drawn upwardly and the latches 36 are disengaged from the steps of the vertical columns 10. When the solenoids are die-energized, the counterbalanced dogs or latches swing back for re-engagement with the column steps.

Vertical adjustment or movement of the platform assembly along the columns l is accomplished by the coordinated shifting and latching of the upper and lower frames, 22 and 23 respectively. Power for moving this assembly is supplied by a motor 49 which has its rotatable shaft 50 coupled to a pump 51, as diagrammatically represented in Figure 8. -Condui'ts 52 and 53 carry hydraulic fluid through pump 51 and toward and away from valve 54,

The control valve 54 is also connected by branched conduits 55' and 56 to a plurality of double-acting hydraulic cylinders S7. While four such cylinders are shown in Figure 8, it will be understood that a diierent number of cylinders might be provided, depending upon the size and capacity of a scaiold structure.

The valve S4 is equipped with a reciprocating valve member 58 which partitions the valve and directs the iiow of pressure fluid therethrough. The particular valve member shown in the drawings is movable to either of two positions and is directed to these positions by means of solenoids l59 andV 60. When solenoid 60 is energized, valve member S is shifted into the illustrated position and directs Huid entering from conduit 52 into the outgoing conduit 55. Pressure fluid is thus carried into the upper portion of each of the hydraulic cylinders 57 and forces the piston rods 61 in a downward direction. At the same time, fluid is drawn from the lower portions of the cylinders through conduit S6, valve 54 and conduit S3 and is finally recirculated by pump 5l.

When so-lenoid 59 is energized, the hydraulic iluid ilcwing from pump 5l into conduit 52 is instead directed by valve 54 into the conduit 56. Therefore, i'luid is forced into the lower portions of cylinders 57 and the piston rods are pushed upwardly. Pressure fluid is simultaneous ly carried from the upper portion of the cylinders by conduit 55 and returns to valve S4 and pump 51.

As best shown in Figures l, 5 and 6, lthe hydraulic cylinders 57 and piston rods 6i extend between the upper and lower platform frames 22 and 23 respectively. The motor 49, pump 5l, valve 54 and valve controlling solenoids 59 and (til are preferably encased within a single housing 62 carried between the upper and lower frames, as viewed in Figure l. For the purpose of clearly setting forth the present invention, other features of the driving means, such as conduits 52, S3, 55 and 56 and the electrical control and safety apparatus to be described shortly, are illustrated only in Figure 8 and are not represented in Figures l-7.

The cylinders 57 and piston rods 6l are secured to the upper and lower platform frames by any suitable mounting means, such as by rivets 63. When pressure iiuid forces the piston rods downwardly, frames 22 and 23 are pushed away from each other and the platform assembly is extended, as in Figure 5. On the other hand, if the piston rods are drawn upwardly, the frames are drawn together and the platform assembly is retracted (Figure 6). When these retractions and extensions are coordinated with the latching and unlatching of dogs 36 upon column steps 15, the assembly may be selectively lowered or lifted along the vertical columns.

To reduce friction between the platform assembly il and the columns 10 during a lifting or lowering operation, and to insure smooth operation of the adjustable scaffold structure, l provide the upper and lower frames 22 and 23 with a plurality of platform guide rollers 64 which are adapted to ride in the vertical channels provided by the columns lil.v These rollers are rotatably mounted upon the respective platform frames and may be secured thereto by means of threaded shafts 65 and nuts 66.

For maintaining the platform frames 22 and 23 in horizontal and parallel alignment at all times, l provide a pair of scissor connecting members 67 and 6E on each side of the platform assembly. These scissors are illustrated most clearly in Figures 4, S and 6. Each pair of scissor arms or members are channel-shaped and are intermediately joined by pins or rivets 69. Frictional engagement of the adjacent backsides of the arms may be reduced by bearing discs 70. One end of each of the paired scissor arms is pivotally xed upon one of the frames by rivets 71 and 71a, while the opposite end of each of the two arms is connected to the other frame by the pins 72 and 73 carried by those arms. Rollers 74 and '75 are rotatably mounted upon thc pins or shafts 72 and 73, respectively, and ride in the horizontal channels provided by the C-shaped beams of the upper and lower frames. In addition, the pins extend through slots 76 in the frames to further guide the horizontal movement of the rollers.

The driving means for vertically adjusting the platform assembly includes an electrical circuit illustrated in Figure 8. Lines 77 carry electrical current to motor 49 which operates continuously during elevation and lowering of the platform assembly. The solenoids 59 and 6l) for operating control valve 54 are supplied with electrical current by'lines 78 and 79 respectively, which lead from the two-button control switch S0. The switch 80 is equipped with an upper button 81 and a lower button 82 for operating the two-position valve 54. This switch is in circuit with motor 49 by means of lead 83, and

is also in series circuit with the eight safety switches 43 by means of lines 84, 85 and 86. Also in series circuit with the solenoids 59, 60 and the control switch 80 is a three-position switch 87 supplied with current by lines 88. The switch 87 may be adjusted by knob 89 to a direct current either along lines 90 and 91 to one set of solenoids 45 connected to the dogs of the upper platform frame 22, or along lines 92 :and 93 to the other Set of solenoids 45a for operating the dogs of the lower frame 23.

Each of the solenoids 59 and 60 controlling the position of valve 54 is equipped with a switch 94 and 95 respectively. These switches complete and interrupt an independent circuit comprising signal lights 96 and 97 and lines 98 land 99.

Horizontal adjustment of the scaffold structure is achieved by means of extensible transverse support members 100, 101, 102 and 103 at opposite ends of the upper platform frame adjacent transverse beams 30 and 31, and similar members 104 and 105 between the segments of the longitudinally extending beams 24 and 25 which are,

connected to the plates 32 and 33 as described above. These intermediate support members 104 and 105 are therefore slidable between the adjacent ends of the connected segments of beams 24 and 25 and the connecting plates 32 and 33 above and below the adjacent ends of those segments, as indicated in Figure 4 of the drawing. Most desirably, the extensible channel supports ride upon rollers 106 carried by the transverse beams of the upper frame. Collars 107, 108 and 109 aid in holding the extensible members in extended or retracted position, and also reinforce the transverse beams of the upper platform frame.

Figures l and 4 show expandable floor or platform units 110 longitudinally placed upon the transverse support members and transverse beams of the platform assembly. These units are entirely conventional so that a detailed description herein is believed unnecessary.

Operation In erecting and operating my adjustable scaffolding, l first place each of the base sections 12 of the columns upon any level surface. It is to be understood, however, that all of these column segments need not be arranged on the same horizontal surface. It is necessary only to vertically position the segments 12 so that the difference in elevation thereof is some multiple of the distance between the steps 15.

Next, the platform assembly is placed upon theupright column sections so that the dogs 36 of the lower and upper frames 23 and 22 engage steps 15. Additional column sections may be mounted above those already in place. The scaffolding is then in condition for vertical adjustment.

To raise the platform assembly, button 81 of switch 80 is pressed to energize the solenoid 60. This solenoid draws the valve member 5S into the position shown in Figure 8, and the hydraulic lifts comprising cylinders 57 and piston rods 61 are forced apart by pressure uid pumped by motor 49 and pump 51 through the conduits 52 and 55. The upper frame of the platform assembly is thereby lifted and `assumes the position shown in Figure 6, since the dogs 36 offer no resistance'to upward movement of the platform frames. At the same time, solenoid 60 closes the circuit for signal light 96, and the safety switches 43 engaged by the lever arms of the dogs break the series circuit feeding current to the solenoid 60. The ow of pressure uid to the upper portions of the hydraulic cylinders continues, however, because motor 49 and pump 51 `are on an independent circuit. Moreover, light 96, which is also on a separate circuit, remains lit throughout the period during which the platform frames are being forced apart.

When the hydraulic lifts are fully extended, the counterbalanced ,dogs swing into engagement with the next group of steps 15 and release the arm 44 of the safety switches 43. The handle 89 of the two-position stepping switch 87 is manually or automatically turned so that when the lower button of control switch is pressed, solenoids 45a above the dogs of the lower frame will be lifted and valve controlling solenoid 59 will be activated. Pressure fluid will then flow to the lower portions of the cylinders 57 and the lower platform frame will be retracted or pulled upwardly, as shown in Figure 5. During this retraction, the light 96, remains lit. As the dogs of the lower frame are lifted and that frame is retracted, safety switches 43 break the circuits leading to solenoids 45a and 59, so that when the lifts are fully retracted the counter-balanced dogs may again drop into engagement with steps 15.

The described operation may be continued until the scaffold has reached `any desired height. Bracing, if it is needed, may be furnished by means of cross braces 20. These braces may be easily installed from the operators platform as the scaffolding is raised. When the platform assembly has been raised sufficiently to make bracing advisable, the lower ends of the braces may be secured to the columns by pins or bolts 21. The braces are then moved to a vertical position until the platform assembly has been raised far enough to permit the operator to swing the braces into crossed relation and secure the top ends upon the columns. When the platform assembly is lowered, this procedure is simply reversed.

Throughout the lifting operation, the platform assembly is maintained in a horizontal position. Scissors 67 and 68 along each side of the assembly insure a horizontal and parallel relation between the upper and lower platform frames 22 and 23, despite the fact that the platform assembly may be heavily loaded, or that the loads carried may not be centralized thereon.

It at any time during the lifting or raising operation, the dogs of the upper or lower frames do not properly engage the steps or lugs of the segmented columns, the safety switch 43 of the disengaged latch or dog will remain open, and the circuits leading to the control switch 80, valve controlling solenoidsl 59 and 60, switch 87 and dog lifting solenoids 45 and 45a will not be completed. Further operation of the platform assembly will be impossible until the apparatus is repaired. Either of the signal lights 96 and 97 will remain lit, depending upon whether the frames were extending or retracting at the moment of improper latching, and will not only warn the operator of the defective operation but will indicate the particular level of dogs where the defect has occurred.

When the platform assembly has been elevated to the desired height, it may then be horizontally adjusted by laterally extending the sliding support members 100, 101, 102, 103, 104 and 105, and laying the longitudinally expandible floor or platform units thereacross. Generally, these outside platform portions will be used as walkways and will not carry heavy loads. It will be understood, however, that these walkways may be made to carry any load required by altering or increasing the dimensions of the sliding channel supports.

The lowering of the platform assembly is simply the reverse of the above described operation, with the additional requirement that the dog lifting solenoids 45 and 45a must be energized each time the platform frames are retracted and extended. This is accomplished by means of the switch 8'7, which directs current either to the lower set of solenoids 45a operating the dogs of the lower frame 23, or to the upper group of solenoids 45 connected to the dogs or latches of the upper frame 22. While I have described and shown a manually operated switch 87, it will be apparent that the operation of this switch might be automatic and coordinated with the functions of control switch 80 in order to simplify the manual operation of my scaffolding.

When the platform assembly has been lifted to the desire'd working elevation, it may be necessary or desirable to also `perform additional work at a still higher level. This may be accomplished by mounting a second `platform assembly upon the vertical columns holding the first assembly, and thereby independently operating two or more assemblies 'along one set of columns. Additional platform assemblies may also be used upon the same set of columns where an obstruction, such as a beam or brace of a building or other structure, prevents further elevation -of one of the assemblies.

Although only one set of segmented columns and a single platform assembly has been illustrated, it is to be understood that other sets of columns may be erected and additional assemblies may be locked to the connecting plates 26, 27, 28 and 29 of the frames 22 and 23. Furthermore, a group of scaffold units interlocked in this manner may all be elevated or lowered by operating a single set of controls, since the electrical circuits for the combined platform assemblies may be coupled to each other.

While l have disclosed my adjustable s'calfolding in considerable detail for purposes of illustrating one embodiment of this invention, it will be understood by those skilled in the art that numerous changes may be made in those details without departing from the spirit and principles of my invention.

I claim:

1. An adjustable scaffolding comprising a plurality of verticallyextending columns, each of said columns being composed of a pluralityof interlocking vertical segments and being provided with a plurality of uniformly spaced steps, a platform assembly having an upper and a lower horizontal platform frame, hydraulic means being mounted upon said frames and extending therebetween for alternately moving said frames away from and towards each other, said `frames 'each being equipped with a plurality of latches adapted to alternately engage and disengage said steps in coordination with the alternating operation of s'aid hydraulic means, and electrical power means for operating and synchronizing said latches and hydraulic means, whereby said platform assembly is lifted and lowered along said vertical columns.

2. The structure of claim 1 in which said platform assembly is also provided with scissor connecting members' mounted upon said upper and lower frames and eX- tending therebetween for maintaining said frames in parallel and -horizontal alignment.

3. Thestructure of claim 1 in which said platform assembly isprovided with safety switches for interrupting said electrical means when said latches are disengaged from said steps.

4. An 'adjustable scaffold structure comprising a plurality of vertical columns, a platform assembly adapted to move yupwardly'and downwardly along said columns and comprising an upper and a lower frame each equipped with a plurality of latching members movable between engaging. and disengaging positions with reference to said columns, driving means for moving said frames alternately towards and away from each other, and means for simultaneously moving all of the latching members of one of said frames into column-engaging positions and simultaneously moving all of the latching'members of the other of said frames into column-disengaging positions in synchronization with the alternating movement of said frames towards and away from each other.

5. The structure of claim 4 in which said platform assembly is also'provided with scissor connecting members mounted upon said upper and lower frames and extending therebetween for maintaining said frames in par- I CII 7. The structure of claim 4 in which said platform assembly is equipped with connecting plates for slidably receiving said columns, said connecting plates being adapted for coupling said assembly'with other platform assemblies similarly movable along other vertical co1- umns, whereby a kpluralityof assemblies may be coupled together for simultaneous operation.

8. An adjustable scaffold structure comprising a plurality ofupstanding columns, a platform assembly adapted rmove upwardly and downwardly along said hcolumns and having upper and lower horizontal frames, driving means for cyclically moving said frames towards and away from 4each other, said frames each being equipped with a plurality ofmovable latching members alternately c'igagcable with and disengageable from said columns in coordination with the cyclic movement of said frames, and vmeans for synchronizing the movement of all -of the latching members of each frame for maintaining said frames in horizontal relation.

9. The structure of claim 8 in which said driving means comprises at least one piston assembly extending between said upper and lower frame and being expandable and retractable in response to fluid pressure for moving said frames towards and away from each other.

10. The structure of claim 8 in which said l platform assembly is equipped with connecting members for slidably receiving said columns, said connecting members being adapted for coupling said assembly with other platform assemblies similarly movable along other vertical columns, whereby a plurality of platform assemblies may be coupled together for simultaneous operation.

11. An adjustable scaiolding comprising a plurality of vertically extending columns each having a plurality of uniformly spaced steps, a platform assembly having an upper and a lower frame, driving means mounted upon said frames and extending therebetween for alternately moving said frames towards and away from each other, said frames each being equipped with a plurality of movable latches for alternately engaging and disengav. ing said steps in coordination with the alternating operation of said driving means, and means for synchronizing movement of the latches of each platform, whereby, the latches of each platform are simultaneously moved into engagement with and disengagement from said steps for maintaining said frames in horizontal positions.

12. The structure of claim 11 in which said driving means comprises at least one piston assembly expandable and retractable in response to fluid pressure for moving said frames toward and away from each other.

13. An adjustable scaffolding comprising a plurality of vertical columns, a horizontal platform assembly adapted to move upwardly and downwardly along said columns, driving means for moving said assembly vertically along said columns, said assembly including a plurality of latching members movable between engaging and disengaging positions with reference to said columns, and means for simultaneously moving all of said latching members between column-engaging and column-disengaging positions in synchronization with the operation of said driving means for maintaining said platform assembly in horizontal condition at all times.

References Cited in the le of this patent UNlTED STATES PATENTS 103,899 Lewis June 7, 1870 996,982 Gaulton July 4, 1911 1,195,976 Chesebro Aug. 29, 1916 1,395,346 Lux et al Nov. 1, 41921 1,630,191 Liberman May 24, 1927 1,922,069 Adams Aug. 15, 1933 2,216,912 Hoitsma Oct. 8, i940 2,309,210 Phillips lan. 26, 1943 FOREIGN PATENTS 637,243 France Apr. 25, 1928

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