US2724379A

US2724379A - Automatic surfacing machine

Info

Publication number: US2724379A
Application number: US361001A
Authority: US
Inventors: Omar S Swenson
Original assignee: JOHN SWENSON GRANITE CO Inc
Current assignee: JOHN SWENSON GRANITE CO Inc
Priority date: 1953-06-11
Filing date: 1953-06-11
Publication date: 1955-11-22
Anticipated expiration: 1972-11-22

Description

Nov. 22, 1955 o. s. SWENSON AUTOMATIC SURFACING MACHINE 7 Sheets-Sheet IL Filed June 11, 1953 IN V EN TOR. @411 dwmam BY F I ll.lll|ll.llnl|llli.l.llnlll 1 firm ll Nov. 22, 1955 o. s. SWENSON AUTOMATIC SURFACING MACHINE 7 Sheets-Sheet 2 Filed June 11, 1953 INVENTOR. M V {10mm Nov. 22, 1955 o. s. SWENSON AUTOMATIC SURFACING MACHINE 7 Sheets-Sheet 3 Filed June 11, 1953 INI'EN'I'OR.

Nbv. 22, 1955 o. s. swENsoN AUTOMATIC SURFACING MACHINE 7 Sheets-Sheet 4 Filed June 11, 1955 INVENTOK.

Nov. 22, 1955 o. s. SWENSON AUTOMATIC SURFACING MACHINE 7 Sheets-$heet 5 Filed June 11, 1953 IN V EN TOR.

Nov. 22, 1955 o. s. SWENSON 2,724,379

AUTOMATIC SURFACING MACHINE Filed June 11, 1953 7 Sheets-Sheet 6 IN V EN TOR.

Nov. 22, 1955 o. s. SWENSON 2,724,379

AUTOMATIC SURFACING MACHINE Filed June 11, 1953 7 Sheets-Sheet '7 IN VEN TOR.

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Patented Nov. 22, 1955 2,724,379 AUTOMATIC Omar S. Swenson, Concord, H., assignor to The John Swenson Granite Co., Inc., Concord, N. H., a corporation of New Hampshire Application June 11, 1953, Serial No. 361,001

40min (c1. 125-4 This invention comprises a new and improved automatic surfacing machine for surfacing blocks or slabs of stone, either natural or artificial, by forming thereon interrupted parallel markings producing a bush-hammered finish.

The object of the present invention is to provide a machine having an automatically controlled and guided tool for this bush-hammered type of finish.

in using machines and tools heretofore available for doing this work much unnecessary time is lost and many irregularities in the surface finish are introduced by the tool being under manual control. It is mybelief that by mechanically guiding a conventional or any other tool holding carbide tipped or otherlong lived chisels (known in the granite trade as cuts), it possible to make a more mechanically precise finish in considerably less time than with machines now in use.

My invention utilizes, as one feature, a surfacer bush chisel with a square shank which is inserted into a tool carrier with a. square hole in thenose bushing. This sectional shape of the bush chiseh shanlt and hole in nose bushing could be of any shape so longas the bush chisel is guided and prevented from twisting. The bush chisel may be used in any impact producing surfacer tool, pneumatic, electric or mechanical. Thus by propelling this guided tool carriage along a bridge or ways, the speed of which would be variablefor attainment of different surface finishes and reversible automatically at the ends of each pass along a stone, together with automatic index or set over of tool at each reversal dependent upon the width of tool, the machine need only be set up correctly over a stone and when the stops or automatic control devices hereinafter described are set and the impact tool started, it needs no supervisory attention until the stone surface is completely covered by the tool. At that time all parts of the machine are brought to rest with the surface uniformly finished. The ratesof travel and amount of index are fully adjustable by the operator while the machine is run ning to allow for selection of the desired surface finish.

The machine of my invention is characterized by a supporting frame having a bridge that may be adjusted vertically in accordance with the height or thickness of the stone to be finished, and which carries a fiuidoperated tool imparting about 800 blows per minute to the work.

Going more into detail, the machine of my invention includes parallel beams for supporting the bridge at opposite ends and mechanism forsimultaneously raising and lowering the beams so thatthe bridge is maintained in level condition in all positions of adjustment. As herein shown the supporting beams are arranged to slide upon vertical columns and at thehead of each column is provided a pulley from which a beam is suspended at one end. Connections are provided for rotating all the pulleys simultaneously and so raising or lowering the beams.

The tool carrying bridge member is mounted for transverse indexingupon its supporting beams and mechanism is provided for moving the bridge transversely a stepby-step manner as each successive row of cuts is formed in the surface of the stone being treated. A preferred mechanism for effecting this transverse indexing of the bridge includes a fluid operated ratchet mechanism and sprocket chain connections to both ends of the bridge.

The tool carrier, is mounted for longitudinal feeding movement in both directions along the bridge, and as a preferred mechanism for effecting this operation the bridge is shown as carrying a reversing motor, a transmission unit and sprocket chain connections to the tool carrier. As

herein shown the mechanisms for indexing the bridge and for feeding the tool carrier thereon are automatically controlled so that the feeding direction of the tool carrier is reversed when the tool reaches either end edge of the stone and at the same time the bridge is indexed transversely so as to locate the tool properly for movement in a path parallel to that through which it, has previously moved. Controlling mechanism is further provided whereby these adjusting movements may be regulated in accordance with the dimensions of the stone being treated.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings in which:

Fig. l is a View of the machine in front elevation,

Fig. 2 is a corresponding view in end elevation,

Fig. 3 is a plan view,

Fig. 4 is a detailed plan View on an enlarged scale of the ratchet driving mechanism for traversing the bridge,

Fig. 5 is a cross-sectional view on the line 55 of Fig. 4,

Fig. 6 is a vieW in perspective of the surfacing tool,

Fig. 7 is a view in longitudinal section of the tool holder,

Fig. 8 is a corresponding end view,

Fig. 9 is the Wiring diagram of the machine, and

. Fig. 10 is a view in end elevation of the tool carrier.

The machine is erected on a concrete foundation it] upon which may be placed heavy wooden supports 11 for the block or slab 12 of stone to be surfaced. Corner posts or

columns

13, 14, 15 and 16 are arranged in rectangular pattern upon the base. The

columns

13 and 14 at one end of the frame are tied together at their upper ends by a transverse tie beam 23, the columns 15 and 16 are connected at their upper ends by a transverse tie beam 24, and the

rear columns

14 and 16 are connected by a longitudinal tie beam 37. It will be seen that the frame thus includes overhead supports at both ends and across the back While it presents an unobstructed space at the front so that work pieces such as large stone blocks or slabs may be conveniently placed in position while suspended from a crane. Sleeves 18 and 19, slidable upon the

columns

13 and 14, carry between them a transverse supporting beam 17. Similarly the column 15 carries a sleeve 21 and the column 16 a sleeve 22, and these sleeves are connected by a transverse supporting beam 20. These two supporting beams are arranged to be simultaneously adjusted up and down upon their columns by mechanism which will now be described.

A worm wheel 25 is mounted upon a shaft 28 journaled in the longitudinal tie beam 23. The worm wheel is turned by a worm on a shaft 26 carrying at its outer end a pulley 27 from which is suspended a chain loop by which the worm and the worm wheel 25 may be rotated in either direction. The shaft 28 is provided with a pulley 29 located inside the tie beam 23 and adjacent to the colurnn 14. The worm wheel shaft 28 extends longitudinally to a bearing provided for it in the tie beam 24 adjacent to the upper end of the column 16 and is there provided with a second pulley 30. A cord 31 is fast to the pulley 29 and arranged to be wound thereon and to pass from there to a pulley 32 journaled in the tie beam 23 adjacent to be Wound on the pulley 30 and passes therefrom to a pulley 34 also journaled in the tie beam 24 and located adjacent to the column 15.. The transverse beam 17 is shown as provided with

eyes

35 and 36 and from these eyes extend cords 31, both wound on the pulley 29. Similar cords 33 pass from the opposite ends of the transverse beam 20 to the pulley 30. From the foregoing description it will be apparent that by turning the worm wheel 25 through its driving worm the two end beams 17 and 20 are simultaneously raised or lowered upon theend columns of the frame and maintained always in parallel relation in all positions of vertical adjustment.

The tool carrying bridge extends longitudinally between the end beams 17 and 20. As shown in Figs. 1 and it comprises a pair of spaced channel irons 40 and 40' secured together at their opposite ends. A sprocket chain 41'is connected'to one end of the bridge as shown in Fig. 2 and leads transversely about sprocket wheels 42 and 43 journaled at opposite ends of the beam 17. The sprocket wheel 42 is fast upon theouter end of a longitudinal shaft 44 which runs from one end of the frame to the other as shown in Fig. 1 and is journaled at its ends adjacent to the

columns

14 and 16. As shown in Fig. 4 a gear 45 is journaled upon the shaft 44 adjacent to the sprocket wheel 42. and connected to a ratchet disk 46 carrying a set of pawls 47 as shown in Fig. 5. The pawls cooperate with a ratchet disk 48 fast upon the shaft 44. The gear 45 is arranged to be oscillated by a rack 49 connected to the piston of a'fluid pressure cylinder 50. The parts above described are mounted in a tray-shaped bracket 51 secured to the transversebearn 17 and movable with it. The shaft 44 carries a sprocket wheel 52 at its end adjacent to the column 16. A corresponding sprocket wheel is mounted in the beam 20 adjacent to the column and driven from the sprocket wheel 52 by a sprocket chain 54. It will be apparent that when the rack 49 is reciprocated by the admission of compressed air or other fluid to the cylinder 50, the shaft 44 will be rotated and through the sprocket connections above described the bridge will be advanced in a step-by-step manner or indexed transversely upon the beams 17 and 20.

The bridge includes a pair of parallel rails or tracks 55 and 55 which, as shown in Fig. 10, are spaced from and supported by the channel irons 40 and 40'. The tool carrier 57 is provided with flanged

lower rolls

56 and 56 which run upon the bottom of the tracks 55 and 55 and with arms 58 carrying flanged upper rolls 59 and 59' which run upon the upper edge of the tracks 55 and 55.

Sprocket wheels

60 and 61 are journaled in brackets at opposite ends of the bridge and connected by a sprocket chain 62 which in its lower stretch is connected to the of the block'12 by suitable adjustment of the slide bar'68.

rear side of the tool carrier 57. The sprocket 61 is fast upon a shaft 63 at the right end of the bridge as shown in Fig. 3 and this shaft is connected by a sprocket chain 64 to a hydraulic transmission unit 65 that is belt driven from a reversing motor 66 mounted on the'outer end of the bridge. are provided for feeding the tool carrier 57 in either direction at slow speed upon the bridge.

Mounted in the rear side of the bridge and upon the lower flange of the channel iron 40 is a slide bar 68 having a clamping screw 69 by which it may be fastened in any position of longitudinal adjustment on the bridge in accordance with the dimensions of the stone being treated. The slide bar 68 carries two flat wedge-shaped cams 70 and 84, the first of these being arranged to contact with a roll on the operating arm of a switch 72 mounted upon the left end of the bridge as shown in Figs. 1 and 9. A corresponding switch 73 is mounted upon the right end of the bridge and is operated by the cam 84 on the slide bar. The switch 72 is arranged in the circuit of the reversing motor 66 so that at a predetermined point the direction of the tool carrier feed is reversed and. thesepoints .of reversal may be made to correspond with the end edges It will thus be seen that power driven means The switch 73 is in circuitfwith a solenoid operating the valve of the cylinder 50 so that each time it is operated by the cam 84 the bridge is transversely indexed one step and these operations also take place when the tool has reached one end or the other of the stone being treated.

The tool carrier, includes a vertical aircylinder 75 having a reciprocating plunger arranged to be operated at about 800 strokes per minute and to engage a tool holder 77 arranged to reciprocate in a bushing 78 as shown in Fig. 7. The tool holder 77 is provided with a square bore for the reception of the shank 79 of the tool itself. This is shown in Fig. 6 and includes a set of four parallel blades 80 which are removably locked in place by a wedge 81. Tools of this character are available to the industry.

The operation of the machine above described will be apparent by reference to the Wiring diagram of Fig. 9. The vertical position of the bridge for the work in hand is first properly adjusted by rotating the pulley 27. The bridge is then adjusted transversely .upon the supporting beams 17 and 20 to bring the tool over one corner of the stone 12. The master switch is then closed'and fluid pressure transmitted to the tool cylinder 75. Simultaneously the motor 66 operates to advance the tool carrier longitudinally along the bridge and this movement continues until the switch 72 is tripped by operation of the slide bar 68. Whenthis occurs the current actuating the motor is reversed and the direction of feed of the tool carrier is correspondingly reversed. At the same time fluid pressure is admitted to the cylinder 50 and through the ratchet mechanism above described and the sprocket chain connections, the bridge is advanced one step transversely so that the'line of cuts made by the tool shall be parallel to and overlap to some extent the line of cuts made before such reversal. .It will be understood that each time the respective switch arms are lifted by the cams 70 or 84, the motor 66 is reversed or the valve of the air cylinder 50 is triggered and the rack 49 advanced to index the bridge. i

The tool carrier on the bridge is operated by a commercially obtainable unit know as the Vickers, variable speed, reversible hydraulic transmission, and the rate of feed is controlled by a lever which is included in this unit.

The indexing of the bridge is controlled through a pin 82 which projects from one side of the rack 49. Movement of the rack is arrested when the pin 82 encounters a pin 83 that may be set in any one of a series of threaded sockets 83' formed in a block welded to the base over which the rack moves.

It will be understood that the machine herein described is adapted to employ tools having blades of other shapes and number from those shown in Fig. 6, or in fact any desired type of impact tool.

The transmission unit 65 is of the hydraulic variable speed type available as an article of commerce.

Having thus disclosed my invention and described in detail an illustrative embodiment thereof, I claim as new and desire to secure by Letters Patent:

1. An automatic surfacing machine comprising four vertical corner columns disposed in rectangular pattern and connected at their upper ends to form a stiff frame, a transverse beam supported horizontally at its ends for vertical adjustment upon each end pair of columns, means adjacent to the columns at the ends of the beams for vertically adjusting the beams simultaneously on the columns while maintaining them always horizontal and in parallel relation, a longitudinal bridge supported at its ends on the transverse beams for adjustment therealong, a tool carrier slidably mounted on the longitudinal bridge, and power operated means for moving the carrier back and forth along the bridge. t

2. The surfacing machine defined in claim 1 plus means of the bridge for moving the bridge a predetermined distheir upper ends along three sides of the rectangular pat- 0 5 6 tance in one direction along the transverse beams as the with the cables and pulleys for raising and lowering the tool carrier approaches one end of its travel on the bridge. beams upon rotation of the shaft, and means for rotating 3. The surfacing machine defined in claim 1 in which the shaft in either direction.

said frame embodies four vertical columns connected at References Cited in the file of this patent tern, the fourth side being open and unobstructed for the UNITED STATES PATENTS presentation of work pieces of large dimensions.

4. The surfacing machine defined in claim 1 in which i232: said means for adjusting the beams vertically on the col- 1,287,346 Kmm 10, 1918 umns comprises vertically disposed cable connections to 1 2 33 313 sidel-its Ja 30 940 and extending upwardly from the beams at the columns, 2,378,903 Baldenhofe June 26, 1945 a pulley at the upper end of each columns forsupporting 2,506,076 Garrison May 2, 1950 its cable, means including a shaft extending across the 2,657,680 Evans Nov. 3, 1953 machine between the end pairs of columns and associated