US2398949A - Portable self-propelled scaffold - Google Patents

Description

IApril 23, 1946, l- H. F. MccLAlN PORTABLE vSELF-PROPELLED scAFFoLD Filed March 23, 1945 7 Sheets-Sheet l INVENTOR.

IZZZZIc Claim .April 23, 1946. H. F. MccLAxN PORTABLE SELF-PROPELLED SCAFFOLD Filed March 23, 1945 April 23, 1946; v H. F. MCCLAIN PORTABLE SELF-PROPELLED scAFFoLD r Filed Marel; 23, 1945 7`sneets-.sheet 4 v elk. I .l. lf!

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PORTABLE SELF-PROPELLED SCAFFOLD Filed March 25, 1945 .7 sheets-sheet 5 www April 23, 1949.

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H. F. MCCLAlN iled March 25, 1945 A PORTABLE SELF-PB OPELLED SCAFFOLD pril 23, 1946.

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Patented Apr. 23, 1946 UNITED STATES PATENTl OFFCE- PORTABLE SELF-PROPELLED scAFFoLn Hugh F. McClain, Long Beach, Calif. Application March 2s, 1945, serialNo. 584,318 L l 10 Claims.

This invention relates to a portable self-prop elled scalold, the primary object of the invention being to provide a scaffold especially designed for use in dry docks or ship-building yards.

An important object of the invention is to provide a scaiold of this character including a pivoted staging section mounted on a movable support, so that the staging may be tilted and secured in its adjusted tilted positions to move the catwalks carried thereby, in proximity to the ship underrepair.

Another important object'of the invention is to provide a scaffold including a pivoted section on which the catwalks are adjustable independently of each other and in horizontal planes so that the forward edges of the catwalks may be moved to positions adjacent to the hull of the ship, to the end that the workers standing on the catwalks may have easy access to their work.

With the foregoing and other objects in View which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations ofrparts hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the.

invention as claimed.

Referring to the drawings t Figure 1 is a side elevational view of a scaffold constructed in accordance with the invention, the pivoted staging sectionthereof being shown in its adjusted position in dotted lines.

Figure 2 is a rear elevational view of the scat fold. Y

Figure 3 is a sectional view taken on line 3--3 of Fig. 2.

Figure 4 is a sectional view taken on line 4 4 of Fig. 3. K

Figure 5 is a sectional view `taken on line 5--5 of Fig. 1. v Y

Figure 6 is a sectional View taken on line 6 6 of Fig. 2.

Figure 7 is a sectional view taken on line 'I-'I ofFig. 6. i

Figure 8 is a sectional View taken on line 8-,8

of Fig. 6. Y Figure 9 is a sectional view taken on line 9-9 of Fig. 3.

Figure 10 is a sectional view taken on line Ill--Ill of Fig. 1.

Figure 11 is a sectional view taken on line II-II of Fig. 2.

(Cl. 304-2) I Figure 12 `is a sectional view taken on line I2-I2ofFig.6. f Figure 13 is an enlarged elevational view illustrating one of the brakes.

5 Figure 14 is a sectional View taken vonl line Ill-IdofFig. 1. ,I Y.

Referring to the drawings in detail, the scaffold embodies a rectangular frame comprising! front and rear channel bars 5 and end bars 6,the bars l0 5 and 6 being welded together at their ends providing an exceptionally rigid structure. y,

This frame provides the chassis for'the 'supporting truck, and has mounted at itsiorward side, caster rollers I.

l5 At the rear corners of the frame, are tubular bearing members 1 ,disposed vertically, andsecured to thebar5 at therear of the-frame, and the rear ends of the end bars 6, by means or the angle plates 8, which are welded to the rear ybar 5 and end bars 6. The lower ends of the tubular bearing members 'Iv are enlarged and formedwith annular grooves to receive Athe ball Abearings 9.

The reference character I0 indicates the forks for thev traction wheels ofthe truckl orA carriage,

the forks I0 having openings toA receive the axles II on which the tubular bearings I2 aremounted.' The tubular bearings are secured within the hubs of the wheels I3 to move therewith. Bev-y eled pinions I4 are secured to the bearings I2,

and are in mesh with the pinionsv I5 secured to the lower ends of the lshaft IE. The shaft I 'is mounted in the bearings II and I8, the bearings fI'I being secured to the forkslll, while' the bear-V ings I8 extend inwardly yfrom the tubular shafts I9 that extend upwardly from the forks it. in the construction of the forks I0, disk-like bearings 2U .are provided, which bearings are valso formed 'with grooves to Areceive the "ball ',bear- 40 ings 9.

closed by the disks 24 which disks provide ,sup-4 ports for the bearing arms 25 which depend therefrom. Y

The shafts 26 extend through' the 'disks 2d and have their lower ends disposed'v within bearing openings formed in the bearing arms 25.

The bearing arms 25 are spaced from the. disks 24, providing clearancesv for the gears ELthat in turn mesh with thegears 28 secured to` the shaft I6. Mounted on the upperv .endsof the shafts 26 are substantially large pinions 2Q- that mesh with the pinions 3B secured to the ends of the power shafts 3l which are mounted in the bearings 32 that are secured to the tubular bearing members 1. Differential gearing of the usual and well known construction, is provided in the gear housing 33 and includes a gear mounted on one end of the shaft 34 which carries the beveled gear 35 at one end thereof.

Secured to each shaft 3| aat a. point adjacent to the diierential gearing housing 33., is a brake drum 35 `and a brake band 35, the brake bands being operated to grip the brake drums to hold either of the shafts 3l against movement in guiding the scaiold. i

Brake-operating levers 31 connect with the brake bands and provide means for operating the brake bands. These brake-operating levers 31 are connected with the pedals 38 for operation by the operator of the scaffold.

A platform 39 forms a part of the truck and extends between the end bars of the frame of the truck. The platform provides a support for the power plant which inthe present showing is in the form of a motor 4B which transmits movement to the shaft 4I through the belt 42 operating over the pulley 43 mounted on the end of the motor shaft, and the substantially large pulley 44 .secured to the shaft 4|. Spaced pinions 45 and 46 are loosely mounted onrthe shaft 4i, the pinion 46 being held spacedfrom the pinion 41, by means of the Abearing48. The pinion .41 is in mesh with the gear 35V to direct motion to the shaft 34 in operating theshaft V3i, through the differential gearing.

Also mounted on the shaft 4| and being in mesh with the gear 35, is a pinion 48'. Pinion 48 is also loosely mounted on the shaft 4l, the pinion 49 being in.r mesh withthe gear 5B which in Yturn is in mesh with the pinion lV which is loosely mounted on the shaft'4i. Gear 5,0 is mounted on one end of .the shaft 52 which carries the worm gear 53 at its free end, the worm gear 53 being in mesh. with the gear t4 secured to the shaft-23.

Disposed between the pinions 45 and 46, are clutch members 5'5 and 58, which are operated by means of the clutch lever 51, to connect either of the pinions 45 or 46. to the shaft 4l.

.Clutch members 58 and 59 are also connected with the shaft 4l' and,v are adapted to be moved into engagement with the pinions. 41 or 48", to connect them to the shaft 4l. These clutch members 58 and 59 are operated by means of the clutch lever BU. Clutch members Yill and E2 operated by means of the clutch lever 63, operate between the .pinions 49 and5l and are adapted to connect either pinion to the shaft 4I to operate the gear 58 and shaft 52 .eitherin a clockwise direction or an anticlockwise direction, to guide the truck.

Rising from the truck, and being rigidly connected therewith, is a. supporting frame for the movable tower section of the scaffold, which comprises rear bars 64 and 65, and front bars 66, the bars 64 and 65 being connected with the front bars 66 by means of the horizontal bars 61, the main or rear bars of the vertical frame ling connected by means ofY the transverse bar Bearings B9 are secured to the. rear bars 64 and provide supports. for the shaft that also extends through the bearings 1|.r secured to the rectangular frame 12 that is secured to the rear bars. The ends of the shaft 10are mounted in bearings 13 that are secured at the ends ofthe frame 12. The shaft 14 carries the pinion 15 at its lower end, the pinion 15 being in mesh with the pinions 5 and i6 so that rotary movement may be directed from the shaft 4I to the shaft 14 in a direction either to the right or lett, for purposes to be hereinafter more fully described.

As clearly shown by Fig. 2 of the drawings, the shaft 14 extends to a point adjacent to the gear 'E6 mounted on the shaft 10, the shaft 1d carrying the worm 1i which is in mesh with the gear 16 to rotate the gear and shaft 18. Beveled gears 'I8 are mounted on the shaft 10, and these beveled gears mesh with the pinions 19 that are secured to the rear ends of the screws 88 that move through the threaded members 8i, which are provided with Shanks 82 that extend through openings in the vertical rear bars of the adjustable tower, forming a part of the scaold. The connection between the members 8i and rear bars of the tower is such that the members 8l may pivot with respect to the tower. The threaded members 88, as shown by Fig. ll, also move through tubular bearings 83 which are pivotally mounted on the shaft 10 of the stationary upright frame. By operating the clutch lever 51, it is possible to rotate the threaded members or screws 86 to move the tower to its adjusted position, or return the tower to a position adjacent to the stationary supporting frame of which the bars 64 and 65 form a part.

The adjustable tower embodies front and rear bars 84 and respectively, which are vconnected by the channel bars 3B by means of bolts-86', the channel bars 85 Vbeing of lengths to extend appreciable distances beyond the front bars 84, as clearly shown by Fig. l of the drawings. These channel bars 8S are arranged in predetermined spaced. relation with respect-to each other and are pivotally connected with the bars 84 by means of bolts 84 Vwhile the rear ends of the bars'o are connected with the bars 85 by the bolts 81, so that .the tower may-swing from the Vertical position shown in full lines in Fig. 1 of the drawings, to the inclined position asshown in dotted lines in Fig. 1 ofthe drawings.

The swinging tower is pivotally connected to the stationary supporting frame, by means of the bolts 84' and 81, the latter bolts being shown as extended through the bars 64 and V(i5 ofthe supporting frame and bars 85 of the tower.V Angular base bars 88V connect the rear bars 85 to brace them against movement with respect to each other. The free edges of the channel bars86 are turned inwardly, providing tracks 89, as shown by Fig. 8. Secured to the channel members 86 and disposed within the connes of the flanges thereof, are pulleys '90 over which the cables 9| operate. Y

The c'atwallrsv indicated by the reference character 92 embody ooring boards 93 that' are bolted to the angle bars 94 by means 'of the bolts 95, which are shown as passing through openings in the ooring, and through aligning openings in the angle bars 94. The openings in the flooring at one end of -ea-ch catwalk, are elongated as shown at 96, to the end that the ooring may be adjusted from the full line position as shown by Fig. l0 of the drawings, to the dotted lineposition, wherein the outer edges of the catwalks may ,be moved to positions to conform to the .general contour of the hull of a ship with whichthe scaffold is being used. I

The angle bars 94 provide supports for the grooved supporting wheels 91 which are mounted on the shafts 98 that extend through the angle bars 94 and are secured.y thereto. by means 'of the nuts 99. The grooved 'supporting wheels 91. operate over the tracks 89, 'as shown -by Fig?. "7. of thedrawings. f ff Supported by the angle bars 94 and movable therewith, are pairs of brake arms that are pivotally mounted on the bolts |0| that are shown as extended through the housing |02. Springs |03 Vconnect the brake arms of"opposite'pairs, as shown by Fig. 6 of the drawings. These brake arms |00, are relatively long so that when they are moved in one direction, they will set upa binding action with the tracks 89. :The ends of the arms |00 are forked, so that they fit over the tracks. g

Mounted for sliding movement on the housing |02, is a plate |04 that has inwardly turned parallel anges |05 which'are so positioned that when the plate |04 is moved longitudinally of the housing, the ends of the anges will engage the brake arms |00 to force the arms forwardly out vof contact with the tracks. The arms at the opposite end of the housing will trail,` allowing theV catwalks lto be adjusted with respect to the tower, so that predetermined catwalks may be moved outwardly to contact with the hull of the ship with which the scaffold is being used, so that the operators may work in close proximity to the hull of the ship. The cables 9| which connect with the plate |04, move over the pulleys 90, and extend to positions wherein the operators may have easy access thereto to accomplish the adjustment of the catwalk as described. It will be seen that under normal conditions, the springs |03 will operate to cause the free ends of the brake arms to frictionally engage the tracks 89, securing the catwalks in their positions of adjustment. When it is desired to move the catwalks in the opposite direction, the cable 9| at the,l opposite end of the plate |04 will be operated to move the brake arms at this end of the plate, out of contact with the tracks, whereupon the catwalks may be moved in the opposite direction, the brake arms at the opposite end of the plate, trailing during this movement.

In the operation of the device, the motor 40 is set in motion 'directing rotary movement -to the shaft 4|. The clutch lever 00 is now operated to clutch either the pinions 41 or 48 to the shaft, whereupon rotary movement is directed to the gear 35. The shaft 34 is now operated to direct rotary movement to the shaft 3| through the differential gearing within the gear housing 33. The shaft 3| operates the shaft I6, through the gearing shown by Fig. 9 of the drawings, and these shafts rotate the wheels I3, through the beveled pinions |4 and pinions I5.

When it is desired to turn the truck in moving the truck to its proper position with respect to the ships hull, the clutch lever 63 is operated to rotate the shaft 23 which in turn rotates the forks |0 in which the wheels I3 are mounted. The desired brake pedal is now operated to lock one of the shafts 3| while the other shaft rotates the wheel at the opposite end of the truck, after the truck has been moved to a position adjacent to the hull of the ship, the clutch lever 51 being operated to rotate the shaft 14 and screw 80 to move the tower to the desired position. In order to adjust the catwalks so that they will move to positions to conform with the contour of the hull of the ship, the cables 9| are operated in a manner as previously described to move the catwalks independently of each other. The catwalks will 'sand from sand blasters or the like.

Inview of the foregoing detailed description, it is believed that a further .detailed description as to the operation of the device is unnecessary.

What is claimed is:

l. A scaffold embodying a truck, a vertical supporting frame mounted on the truck, a tower pivotally mounted at the upper end of the supporting frame, a plurality of vertically spaced catwalks mounted on the tower and extending forwardly therefrom, and an adjusting means for moving the catwalks in horizontal planes at right angles to the tower, independently of each other.

2. A scaiold embodying a truck, a vertical supporting frame mounted on the truck, a tower, means for mountingA the tower for swinging movement on the supporting frame, adjusting screws adapted to swing the tower on the supporting frame,.said adjusting screws adapted to also hold the tower in its positions of adjustment, superposed catwalks mounted on the tower and adapted to extend beyond the front edge of the tower, and means for adjusting the catwalks at right angles to the tower and in horizontal planes towards or away from the tower independently of each other.

3. A scaffold embodying a truck, a support rising from ther truck, a tower mounted for vertical swinging movement on the support, adjusting screws adapted to move the tower to various angular positions with respect to the support, catwalks mounted on the tower and arranged in vertical spaced relation with respect to each other, and means for adjusting the catwalks in a line at right angles to the tower and with respect to each other in horizontal planes.

4. A scaiold embodying a truck, a support mounted on the truck, a tower pivotally mounted on the support and being extended an appreciable distance above the support, catwalks mounted on the tower in vertical spaced relation with respect to each other, and means for moving the catwalks in horizontal planes independently of each other in a. line at right angles to the tower.

5. A scaifold embodying a base, a support mounted on the base, a tower pivotally connected to the support at a point intermediate the ends of the tower, lchannel bars providing tracks, secured to the tower, catwalks, said catwalks including rollers movable over the tracks, whereby said catwalks may be extended beyond the front of the tower independently of each other, pairs of brake arms mounted on each catwalk, said .Y brake arms adapted to normally prevent movement of the catwalks by frictional contact with said tracks, operating cables, means operated by the cables for moving predetermined brake arms out of contact with the track, whereby said catwalks are extended beyond the front of the tower, I

independently of each other.

6. A scaffold embodying a base, a tower mounted on the base for vertical swinging movement, movable catwalks supported on the tower and being disposed beyond the front of the tower, and means for advancing the catwalks in horizontal planes at right angles to the tower, towards and away from the tower independently of each other beyond the normal retracted positions of the catwalks. Y

7. AV scaffold comprismg a base, a tower 'niv otally mounted on the baseand embodying vertical bars, channel bars ypivotally connected With said vertical barst .said channel bars having their open sides disposed inwardly, providing tracks, said channel hars being extended forwardly beyond the tower, catwalks mounted on the extended ends Vof the channel bars of the tower and being disposed in vertical kspaced relation with respect to each other, rollers mounted on the catwalks and operating over the tracks whereby said catwalks may be extended beyond the forward ends of the channel members, independently of each other.

8. A scailold comprising a support, a tower pivotally ,mounted on the support, threaded pivoted bearings mounted on the tower, threaded members mounted on the support and being movable through the threaded bearings whereby said tower may `be swung to various angular posit-ions with respect to the support, and a plurality of fcatwalks arranged in vertical spaced relation with each other on the tower.

9. A device of the character described, comprising a tower embodying vertical bars, channel bars pivotally connected to the vertical bars, said channel bars yhavingr their open sides :disposed inwardly providing tracks, movable catwalks including angle bars, rollers mounted on the angle bars, said rollers operating over the tracks, pairs of pivotally connected inclined brake arms mounted on each catwalk, said .brake arms r'l'laving :forked ends adapted to straddle said tracks, frictionally engaging the tracks and normally securing the catwalks against movement, means for movin-g the catwalks along the'tracks, said moving means .adapted to -disengaee certain of said arms and tracks. i l0. A device of the character described, comprising a tower, horizontal tracks mounted on lthe tower, catwalks movable over the tracks, pairs of pivoted braker arms Amounted on the catwalks, means for urging said brake arms into frictional contact with the tracks, normally securing said catwalks against movement, means for moving the catwalks'along the tracks, and said catwalkmoving means adapted to release said brake arms. l

HUGH F. MCCLAIN.

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