US1645414A - Stepladder-assembling machine - Google Patents

Description

- J. E. KALGREN STEPLADDER ASSEMBLING MACHINE Filed Feb. 1 1927 5 sheets-sheet 1 lam Job]; fia'lgren Oct. 11 1927.

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J. E. KALGREN STEPLADDER ASSEMBLING MACHINE Filed Fb. 1927 5 Sheets-Sheet 5 ,[zwm/a/ Joby Elfa/ 1'6)? Patented Get. 11, 19 27.

UNITED STATES PATENT OFFICE.

JOHN E. KALGREN, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR T J R. CLARK COM- PANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION OF MINNESOTA.

STEPLADDER-ASSEMBLING MACHINE.

Application filed February 16, 1927. Serial No. 168,662.

My present invention has for its object to provide a highly efiicient machine for use in quickly and accurately, assembling the parts of a step ladder proper and clamping the same together under pressure and thus holding the same while said parts are being rigidly connected by suitable fastening de vices and then quickly releasing the same. Said machine is adapted for use in assembling step ladders of various different lengths without changing the adjustment thereof.

Generally stated, the invention consists of the novel devices and combinations of devices hereinafter described and defined in the claims.

In the accompanying drawings, which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a front elevation of the step ladder proper;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1;

Fig. 3 is a plan view ofthe step ladder assembling machine;

Fig. 1- is a longitudinal vertical section taken on the irregular line 14; of Fig. 3 and also showing the partsof a step ladder assembled therein; A

Fig. 5 is a detail view showing one of the step clamps set;

Fig. dis a rear end elevation;

Fig. 7 is atransverse vertical section taken on the irregular line 7-7 of Fig. 3 and of the step ladder parts shown in Fig. 4;;

, F 8 is a transverse vertical section taken on the line 8 8 of Fig. 3;

Fig. 9 is a detail view, with some parts sectioned on the line 9--9 of Fig. 3; and

Fig. 10 is a detail view showing one of the adjustable side rail positioning stops.

Figs. 1 and 2 are views showing a step ladder proper which has been assembled by means of the improved machine and the parts thereof rigidly and permanently connected while held in said machine.

Of theparts of this step ladder, the numeral 10 indicates a pair of converging side bars 11 the steps or treads, 12, the headed nutequipped crosstie. rods, and 13 the washers under the heads and nuts of said rods. steps 11 have their end portions mounted Said in transverse oblique grooves 1&1 in the inner faces of the side bars 10. I It will be noted.

that the steps 11 are wider than the side bars 10, project forward thereof, and their front corners are beveled at 15 to meet said bars. The rear longitudinal edges in the steps 11 are beveled flush with the rear longitudinal edges of the side bars 10. The rods 12 extend through aligned bores in the side bars 10 and longitudinal grooves 16 in the under step ladder assembling machine, the numeral 19 indicates a skeleton frame having on its top a plurality of laterally spaced transverse I-beams 20, as shown four, the lower flanges of which rest directly on the top side members of said frame and are rigidly bolted thereto. 4

A. pair of clamping abutments 21 for the step ladder side bars 10 are, as shown, in the form of long fiat bars set vertically edgewiso I in converging relation and have .formed with their lower longitudinal edges, base flanges 22 which rest on crossheads 23 to which they are rigidly bolted. One of these clamping abutments 21 will hereinafter be designated relatively fixed and the other thereof as relatively movable. These crossheads 23 are slidably mounted on the top flanges of the I- beams 20 which afford rails 24 therefor. Ob-

viously, the crossheads 23 support the clamping abutments 21 for independent lateral movement toward and fromeach other.

For supporting the step ladder side bars 10 set vertically edgewise in laterally spaced relation there is provided a pair of gauge of said bars restwith their outer faces flat against the clamping abutments 21. Said gauge rails 25 are attached to the inner faces of the clamping abutments 21 for parallel raising and'lowering movements by headed rails 25 on which the rear longitudinal edges studs 26 which extend through oblique slots 27 in said rails. These gauge rails 25 are adapted. to be adjusted for holding two dif ferent types of steps, one of which has its rear edge substantially flush with the rear longitudinal edges of the side bars 10 and the other of which projects rearward there of. WVhen the gauge rails are adjusted for holding steps of the type in which their rear edges are flush with the rear longitudinal edges of the side bars 10, said gauge rails 25 rest directly on the base flanges 22 and with the upper ends of the oblique slots 27 at the headed studs 26.

To positively hold the gauge rails 25 in either one of these two different predetermined adjustments there is provided. eyebolts 28 pivoted to the rear ends of the gauge rails 25 for vertical swinging movement and co-operating upright anchor plates 29 on the base flanges 22. Said eye-bolts 28 normally lie in notches in the upper edges of the anchor plates 29 and are positively held against endwise movement, for the adjustment shown in the drawings, by pairs of inner and outer nuts 30 and 31, respectively. For

the other or raised, adjustment of the gauge rails 25 there is formed in the inner nuts 30, which are in the form of cylinders, circumferentially extended grooves 32 adapted to be laid in the'notehes in the anchor plates 29. In addition to these two adjustments, the nuts 30 and 31 may be adjusted on the eye-bolts 28 to bring the gauge rails 25 into either oneof their predetermined positions.

Oblique stop angle plates 21 are secured to the clamping abutments 21 on their inner faces at the front of the machine to be engaged by. the beveled ends 17 of the side bars 10 to endwise position the same in the machine, as shown in Fig. 4.

To hold the steps 11 in the machine in .proper alignment wtih the grooves 14 in the side bars 10 and in proper transverse adjustment with said bars, there is rigidly secured to the base flanges 22, inward of the clamping abutments 21, longitudinally spaced pairs of combined step supports 33 and oblique step positioning abutments 34.

.In the present adjustment of the gauge rails 25 their upper edges are flush with the step supports 33 and the step positioning abutments 34 have the same inclination as the grooves 14 and are in alignment with the lower edges thereof. Cam lugs 35 on the step supports 33 direct the steps 11 against the positioning abutments 34. It will thus be seen that with the rear beveled edges of thesteps 11 resting on the step supports 33 and their under sides bearing on the step positioning abutments 34, said steps will be held so that their end portionswill be directed into the grooves 14 under the setting action of the clamping abutments 21, as will presently. appear.

(lo-operating with the step positioning abutments 34 for holding the steps 11 thereon are step clamps 36 arranged in pairs rigidly secured to the outer ends of two-part rock shafts 37, the outer ends of which are journaled in bearings 38 on the step sup ports 33, and which shafts support said clamps for swinging movement toward and from the step positioning abutments 34. The 'two sections of each rock shaft 37 are connected for common rotation but with freedom for limited endwise movement in respect to each other by a coupling 39 in the form of a sleeve having an axial passage that is square in cross section and into which project the squared inner end portions of said shaft section. The couplings 39 are held against axial movementbut with freedom to turn with the rock shaft 37 by a key bar 40 which extends through cirshafts 37 in two sections and mounting the same for endwise movements in couplings 39 is to permit. the required lateral independent movements of the clamping abutments 21.

Each step clamp 36 is provided with a face plate 43 attached to said clamp by upper and lower studs 44 rigidly secured to said face plate and extend through bores in said clamp with freedom for endwise movement. Nuts 45 applied to the outer ends of said studs are arranged to impinge against the back of the clamp 36 and limit the movement of the face plate 43 away from said clamp. Each face plate 43 is yieldingly held projected by a block of rubber 46 mounted in a seat in the respective clamp between the studs 44 and engage the back of said face plate. Nut-equipped studs 47 agchor the blocks of rubber 46 to the clamps 3 Integrally formed with each coupling 39 is a depending arm 43 having a bifurcated lower end. The clamps 36 are simultaneously set and released'by a connecting bar 49 which projects between the prongs of the bifurcated lower ends of the arms 43 and is pivoted thereto by bolts 50. This connecting bar 49 works in notches 51 in the beams 20 which hold the same against lateral movement. A coil spring 52, attached to the front end of the connecting bar 49 andanchored to the frame. 19, yieldingly holds said connecting bar with the clamps 36 released.

'of' the shaft 53 and their other ends are pivoted to and between dependingpairs of ears 57 on the crossheads 23 of the fixed clan'iping abutment 21. Each connecting rod 54 comprises two members connected by fixed clamping abutment 21. To positively 20 'holdithe" crank shaft 53 where set, there is keyed thereto, just inward of its squared end 59, a collar 60 having a pair of circumferentially extended slots 61 through one of which projects a nut-equipped bolt 62 anchored in the frame 19.

Topperatje the movable clamping abut- Inent21 in respect to the fixed clamping abutment 21 and thereby produce the clamping or releasing action, there is journaled in bearings in the beams 20 a rock shaft 63 having crank arms 64 connected to the respect'ive crossheads 23 by connecting rods 65. These connecting rods.65 are extended between and -pivoted to depending laterally spacedpai'rs of ears 66 on the crossheads 23 of the relatively movable clamping abutment 21. -Each.connecting rod comprlses two sections connected by a turn-buckle 67 whereby the operative length of the connecting rods 65 may be varied, at will, to laterally and angularly adjust the movable clamping abutment 21.

The rock shaft 63 is operated by a foot treadle 68 comprising a pair of arms 69 which extend transversely of the machine and are pivoted at 70 to the frame 19 and have their free ends connected by an angle foot bar 71' which extends just outside of the frame 19. A pair of links 72 connect the arms 69 at their intermediate portions to the free ends of a pair of arms 73 keyed to the rock shaft 63. A pair of coil springs 74. only one of which is shown, is attached to the intermediate portions of the treadle arms 69 and is anchored to the frame 19. These springs 74 normally hold the treadle 68 raised with the movable clamping abutment 21 released.

To set the step clamps 36 during the downward movement of the treadle 68 to set the clamping abutments 21, there is keyed to the rock shaft 63 a segmental cam 75 ar-' ranged to engage a cam roller 76 journaled on a collar 77 slidably mounted on the connecting bar 49 and secured thereto in different longitudinal adjustments by a pairof set screws 78. Normally, the cam roller 76 rests in a notch 79 in the cam 75.

To afford access to the side bars 10 and permit the same to be secured to the step '11 by tie-rods, nails or otherwise, there is formed in the clamping abutments 21 notchlike openings 80 opposite each step positioning abutment 34. Intermediate transverse notches 81 are formed in the step positioning abutments 34 to facilitate the insertion of the rods 12 through the grooves 16 or under. the steps 11 in case only end grooves are formed therein. A laterally. movable latch'bar 82 is pivoted to the frame 19 and arranged to swing by gravity over one of the treadle arms 69 when. the treadle 68 is deset.

The machine illustrated is for a step ladder having five steps not counting the top step to be secured to the sidebars 10 by the knees 18. In assembling a step ladder of-th-is size the side bars '10 thereof are endwise" positioned by the stop plates 21. Toada-pt the machine for assembling step ladders having a less number of steps than the one shown. without changing the adjustment thereof, there are provided removable and adjustable stops 83 for the side bars 10. These stops 83 are detachably secured to the inner faces of the clamping abutments 21 by wing nut-equipped bolts 84 inserted through aligned bores in said stops and abutments. To prevent the stops 83 from turning on the bolts 84 and thereby get out of adjustment, there is formed'with the upper edges thereof angle-like fingers 85 which overlie the upper longitudinal edges of the clamping abutments 21. Stop screws 86 have threaded engagement with the fingers 85 and impinge against the upper edges of the clamping abutments21. Obviously, by manipulating the. screws 86, the stops 83 may be adjusted to position their oblique surfaces to the same pitch as the beveled ends 17 of the side bars 10. The clamping abutments 21 will be provided with a plurality of longitudinally spaced bores for the bolts 84 so that the stops 83 may be attached to said abutments in proper adjustment for step ladder side bars 10 of different lengths.

Operation.

Normally, the springs 74 hold the foot treadle 68 raised with the movable abutments 21 released by the connection from said treadle heretofore described. At this same time the spring 52 holds the connecting bar 49 retracted with the step clamps 36 released and the cam roller 76 in the notch 79 of the cam 7 5.

To assemble thestep ladder proper, as shown in Figs. 1 and 2, two of the side bars 10, rights and lefts, are placed in the machine with their rear longitudinal edges resting on the gauge rails 25 and their beveled ends 17 against the stops 21, as shown in Fig. 4. The steps 11 of the proper length are then placed on the step supports 33 with their under sides resting on the step positioning abutments 3a. The rods 12 are then inserted through transverse bores in the side bars 10 and the grooves 16 after applying washers 13 to the headed ends of said rods. With the parts of the step ladder thus assembled the treadle 68 is depressed by stepping on the foot member 71 thereof to force the same down against the tension of the springs 74 to a position in which the latch bar 82 automatically swings over the adjacent treadle arm 73 and holds-the same so that the member 71 may be released. During the initial movement of the treadle 68 the cam is rotated and thereby projects the connecting bar 49 against the tension of the spring 52 and sets the step clamps 36 with their face plates 43 slightly compressed against the upper faces of the steps 11 and. thereby yieldingly clamps the same onto the step positioning abutments 3 Continued downward movement of the treadle 68 will shift the movable abutment 21 toward the fixed abutment 21. This movable abutn'ient 21 will first engage the adjacent ends of the steps 11 and cause the same to enter the grooves 1a in the side bar 10 at the movable clamping abutment '21. Continued inward movement of the movable clamping abutment 21 willcause the steps 1.1 to move endwise on the step positioning abutments 3d and project their other ends into the grooves 14 in the side bar- 10 bearing against the fixed abutment 21. t may be here stated that the yielding face plates 4L3 permit this endwise movement of the steps 11 on the step positioning abutments 34;. The final downward movement of the treadle 68 will hold the side bars 10 tightly pressed against the ends'of the steps 11. Washers 13 are then placed on the projecting threaded ends of the rods 12 and by means of a power operated wrench said nuts are tightly turned onto the rods 12 and at the same time said rods are driven by a hammer through the assembled step ladder by striking on the heads thereof. After the nuts have been completely tightened on the rods 12 the projecting threaded encs of the rods are cut away close to the nuts and upset with a hammer to lock the nuts thereon. In some instances, the steps are secured to the side bars 10 by means of nails, and in other instances certain of the steps 11 may be secured by nails and others thereof by means of the rods 12. After the step ladder has been fully assembled and the parts rigidly secured, as heretofore described, the

foot treadle 68 is released by moving the latch bar 82 laterally out of contact with the engaged treadle arm 69,.to permit the springs 52 and 74 to return the movable parts of the machine to normal position and the assembled step ladder to be lifted from the machine. 7

By applying a wrench to the squared end 59 of the crank shaft 53, after loosening the bolt (52, and giving the 'WIBDCl'l a single throw, the relatively fined abutment 21 may be laterally adj usted. without changing its angularity, to the relatively movable clamping abutment for the purpose 'of adjusting the machine for step ladders of different widths. After the relatively fixed abutment 21 has been adjusted, the bolt (32 will be again tightened to secure the crank shaft 53 and hence the relatively fixed clamping abutment 21 where set. The convergence of the clamping abutments 21 may be varied, at will, by operating the turn-buckles 58 and 66 to vary the operative length of the respective connecting rods.

What I claim is:

1. In a step ladder assemblingmachine,

the combination with a pair of' laterally spaced ladder bar clanipmg abutments, one

of which is movable, ofa step positioning abutment, a step clamp, and operating means 7 for the movable clamping abutment and the step clamp.

2. In a step ladder assembling machine, the combination with a pair of laterally spaced ladder barclamping abutments, one of which is movable, of a step positioning abutment, a step clamp, and operating means for setting the clamping abutments and hav ther combination with ladder bar positioning gauges.

6. The structure defined in claim 1 in further combination with ladder bar positioning gauges mounted for raising and lowering movements.

7'. The structure defined in claim 1 in further combination with a holder for the operating means when the movable clamping abutment and step clamp are set.

8. In a step ladder assembling machine, the combination with a pair of laterally spaced ladder bar clamping abutments, one of which is movable, of a step positioning abutment, operating means for the movable clamping abutment and the step clamp, and yielding meansarranged to be placed'under strain by the setting action of the movable clamping abutment for returning the 0p-' crating means to normal position and the movable clamping abutment to its releasing position.

9. In a stepjladder assembling machine, the combination with aspairof laterally spaced laddenbar clamping abutments, one of which is movable, of a step positioning abutment, astepwclan'ip, operating means for the movable clamping abutments and the step clamp, yielding means arranged to be placed under strain by the setting action of the movable clamping abutment for returning the operating means 'to normal position and the movable abutment to its releasing position, and a second yielding means arranged to be placed under strain by the setting action of the step clamp for returning said connections to normal position and the step clamp to its releasing position.

10. The structure defined in claim further combination with a yielding engaging face plate on the step clamp.

11. The structure defined in claim 1 in further combination with a cam for directing a step onto the step positioning abutment.

12. In a step ladder assembling machine, the combination with a frame, of a pair of laterally spaced ladder bar clamping abutments, one of which is relatively fixed and the other of which is relatively laterally movable, step positioning abutments on the clamping abutments, step clamps on the clamping abutments, and operating means for the movable clamping abutment and having connections arranged to set the step clamps in advance of the setting action of the clamping abutments and holding the same set during the setting of said abutments.

13. The structure defined in claim 12 in which the step clamps co-operate with the step positioning abutments.

- 14. The structure defined in claim 12 in which the step clamps co-operate with the step positioning abutments, and in further combination with movable step-engaging means on the step clamps arranged, when set, to permit endwise movement of the steps on the step positioning abutment during the setting action of the clamping abutments.

15. The structure defined in claim 12 in further combination with yielding means arranged to be placed under tension by said connections during the setting of the step clamps for returning the step clamps and 1 in stepsaid connections to normal position.

men-ts mounted on-the frame for lateral movement'toward andfrom each other, step positioning abutments and step clamps on said abutments, a crank shaft, connecting rods between the crank shaft andone of said clamping abutments and operative under a turning'movement of thecrank shaft to'laterally adjust the connected clamping abutments, locking means for the crank shaft for. holding the connected clamping abutment relatively fixed, and operating means for the other clamping abutmentand having connections arranged to setjthestep clamps.

17. In a step ladder assembling machine, the combination with a frame, of a pair of laterally spaced ladder bar clamping abutments mounted on the frame for lateral movement toward and from each other, step positioning abutments and step clamps on said abutments, a crank shaft, connecting rods between the crank shaft and one of said clamping abutments and operative under aturning movement of the crank shaft to lat erally adjust the connected clamping abutments, locking means for the crank shaft for holding the connected clamping abutment relatively fixed, a rock shaft having crank arms, connecting rods between the crank arms and the other clamping abutments, op erating means for the rock shaft, and connections actuated by the rock shaft for setting the step clamps.

18. The structure defined in claim 17 in which the operative length of the connect ing rods may be varied, at will.

19. In a step ladder assembling machine, the combination with a frame, of a pair of laterally spaced ladder bar clamping abutments mounted on the frame for lateral movement toward and from each other, step positioning abutments and step clamps on.

said abutments, a crank shaft, connecting rods between the crank shaft and one of said clamping abutments and operative under a turning movement of the crank shaft tolaterally adjust the connected clamping abutment, locking means for the crank shaft for holding the connected clamping abutment relatively fixed, connecting means for simultaneously operating the step clamps, and a cam on the rock shaft for operating the con' necting means to set the step clamps and for holding the same set during the setting action of the clamping abutments.

20. In a step ladder assembling machine, the combination with a frame, of a pair of laterally spaced ladder bar clamping abutments, step positioning abutments on the clamping abutments, a two-part transverse rock shaft journaled on said clamping abutments, step clamps on the rock shaft, a cou pling connecting the sections of the rock shaft for common rotation but permitting independent endwise movement thereof durshaft, couplings connecting the sections of the rock shafts for common rotation but permitting independent enclwise movement thereof during the lateral movements of the clamping abutments, means for holding the couplings against axial movement, and operating connections for setting and releasing one of the clamping abutments and having connections for operating the rock shafts including arms on the couplings.

In testimony whereof I affix my signature.

JOHN E. KALGREN.

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