US1957186A - Sand blasting machine - Google Patents

Description

May 1, 1934.

c. T. WEIR El AL 1,957,186

SAND BLASTING MACHINE Filed Apri 3 1929 6 Sheets-Sheet l N Jnve Clarence T wen" t5? Hans J Dernehly 1, 1934 c. T. WEIR r-:r AL 1,957,186

SAND BLASTING MACHINE Filed April 13, 1929 6 Sheets-Sheet 2 y 1, 1934* c.T. WEIR El AL 1,957,186

SAND BLASTING MACHINE Filed April 15, 1929 6 Sheets-Sheet 3 1 l I l Int/67225515 Clarence T 51/617 1170716 JDeT'nehZ y Mum, WWW

y 1, 1934- c. T. WEIR El AL 1,957,185

SAND BLASTING MACHINE Filed April 15, 1929 6 Sheets-Sheet 4 inventin Clarence T weir Hans Jpernehzy 1934- c. T. WEIR ET AL 1,957,186

SAND BLASTING MACHINE Filed April 13, 1929 6 Sheets-Sheet 5 arence-T weir Hans JlYernehZ y 1, 1934- c. T. WEIR ElAL 1,957,186

SAND BLASTING MACHINE Filed April 13, 1929 6 Sheets-Sheet 6 Int/6W5- Clarence T weir Hans J Darnelll atente May 1, 1934 SAND BLAS'EENG MACHINE illarence T. Weir and Hans J. lhernehl, Chicago,

51., assignors to Mott Sand Blast Mfg.

a corporation of Illinois Chicago,

Application April 13,1929; Serial No.;354 ,75i

' 14' Claims.

is invention relates to sand blasting machinesand it has among its objects theprovisionof a machine which automatically leads into the same that are to be-sancl blasted, performs the hiasting'operation, and discharges the object upon, without requiring manual hanoiling of the various erations.

Uther objects of the invention are the various detailed features i the machine which contribute to its efficiency serviceability, as'pointecl out hereinafter.

Although blasting has been, for many years, recogiced one-of the most-dangerousoccupations, heretofore, to our knowledge, almostall g l rovisions'are made for re- A the object in the chamber for a period of Upon the performance or the blasting machine automatically discharges e following object into the chamber. h -"ause of the tendency of the blasting sand or s to etrate into all spaces adjacent the machines presents unusual clifficulties.

Th novel features or our invention will be -l:-estfollowing description of an fromo drawings, wherein a elevation of a sand blasting 1" our invention;

a view of the machine in Fig. l;

n center portion of the e e -V -V of 4 showing the position of the several parts atthe momen when a newobjectnecessary to hold clown the intensity of the 1112.366 or control of the operations" ateo. by the utilization of progressive. to feeding of the objects to be blasted into object from the blasting chamber andn. thereof, reference being bad to hasjusts been brought on the rotary table o'f the blasting chamber;

Fig. 6 is a view similar to'Fig; showingthe several parts a moment later, with therotary table carrying th object to be blasted in'elevatecl posi" :tion

Fig. '7 a transverse sectional view through the machine along the line VII- lli of'l' i 3;

Fig. 8 is an enlarged. transverse-vertical sectionalview through theportion oi the niachine' along the line VlII-VIII'of Fig. 5;

Fig. 9 is anen argecl vertical sectional view through the portion of the inachine-along'line Fg. l is nlargecl horizontal sectional' view tlrough-the machine along line X-X of Fig. 5;

Fig. 11 is a" vertical'sectional View throughthe lower end of the main sand hoppers with the feed. nozzle-- attached thereto;

i 'Figf12 is a transverse sectional view along the Fig.13 is a sectional view through a blast noz- 2 zle; and

Fig. 14 is a sectional'view similarto'theyiew shown in 5'illustratins modifiediorm of thetable driving mechanism.

The sand. blasting machine exemplifying the invention, as shown inthe drawingscomprises an elongated rectangular casing"21= macle-of sheet metal-plates and angle irons to constitute 35 a rigid and substantial structure,- the casing .21 being supported above the-floor level 22by an angle iron framework 23.

The casing 21 consists-of several sections, namely, a loading section 24- at the front of the a blasting. ection 25 in thecenter of the machine, and a dischargesection 26 at the rear'of the machine. The blasting section has the form of a large hopper formed by two inclined sheet metal plates 2'? converging downwardly toward the center and having a wide opening'28 at the bottom into a lower-extension 29 formeclinto two hopper sections 30 and 31.

*Directly above the opening 28 of the main'ho per 25' there is formed a blasting chamber 33, the two side Walls 34 of the machine casing constituting the side walls of the chamber anclflexible walls or aprons 35 and 36 constituting" the front and rear walls of said chamber. The inclined front wall 27 of the hopper 25"hasan opening 38 through which the objects to be blasted are loaded from the loading section 24 into the blasting chamber-33. "The inclined rear wall27 of the hopper 25 has a similar opening 39' through which theobJects-blastedare clischarged into the discharge section of the easing after performance of the blasting operation. At the front wall of the casing 21 there is provided an entrance opening 41 into the loading chamber 24, the opening being closed by a curtain 42 of yieldable material, such as rubber. The rear wall of the casing has a similar opening 43 for removing the objects blasted from the discharge section 26, this opening being closed by a curtain 44 like the opening ii. The bottom wall of the loading section 24 is formed into a hopper 45, designated here as the loading hopper, and the bottom wall of the discharge section is formed into a hopper 46, designated here as the discharge hopper.

In order to carry the objects to be blasted from the entrance opening ll toward the blasting chamber 33, there is provided a loading track 51 extending through the loading section 24 in the direction toward the opening 28 into the blasting chamber 33. A discharge track 52 disposed on the other side of the blasting chamber 33 and extending through the discharge section 26 serves to carry away the objects blasted.

The loading track 51 comprises a set of cylindrical rollers 53 extending between two side bars 54. The rollers are arranged to be rotated by means of a driving belt 55 which is driven at the inner end by a driving pulley 56 and is trained at the other end over a pulley 57. The belt is held pressed against the rollers by means of auxiliary rollers 58 pressing downwardly against the upper side of the belt. Because of the rotation of the rollers 53 objects having flat bottoms will be carried forward from the entrance opening ll towards the blasting chamber 33. As seen in the drawings, the rollers 53 are so mounted that the track formed by them is inclined in a direction toward the entrance on the track so as to avoid forward movement of the objects loaded by gravity, and to rely merely on the rolling action of the rollers 53 for carrying the objects forward toward the blasting chamber. The discharge track 52 is likewise formed by a series of rollers 59 supported between two side bars 60. The rollers 59 form a plane inclined in the direction toward the discharge opening 43 so that the objects placed thereon will move by gravity toward said discharge opening. In the center of the blasting chamber 33 there is mounted, at about the height of the loading and discharging tracks, a rotary table 61 by means of which the objects that are to be blasted are rotated during the blasting operation. This rotary table and the associated parts are shown in detail in Figs. 5, 6 and '7.

The rotary table 61 comprises a circular top plate 71 which is held on the upper end of a hollow sleeve 72 which is slidably and rotatably mounted over a hollow stud 73 projecting upwardly from a base plate 74 that is secured to lugs 75 extending from the side walls of a table driving chamber 75 which completely encloses the entire mechanism for driving the table. The lower end of the sleeve 72 forms a cam surface 76 engaging at one point a cam roller 77 which is journaled on a pin 78 secured to the hollow stud 73. The cam surface 76 constitutes a horizontal annular path having at one part of the periphery a depressed portion 7. Accordingly, the sleeve 72 will be in the lowered position, as shown in Figs. 5 and 9, during the period of the rotary movement of the sleeve when the cam roller 77 is in engagement with the depressed portion 79 of the cam surface, and the sleeve '72 with the table top plate '71 will be in raised position throughout the remainder of the rotary movement of the sleeve around the stud 73. There is further provided on the outer side of the sleeve 72 a ring gear 81 adapted to engage a pinion 82 which is mounted on the upper end of a short shaft 83 that is journaled within the base plate 74. At the lower end of the short shaft 83 is mounted a bevelled gear as that is driven by another bevelled gear 55 which is mounted on a horizontal table drive shaft 85 which is journaled in the bearings 87 held in the side walls of the table driving chamber 75. The teeth of the pinion 82 are so arranged as to secure slidable engagement with the teeth of the gear 81 throughout be full length of the longitudinal me t of the sleeve 72. On both sides of the table 61 are mounted two transfer belts 91, 92 extending between the rear end of the loading track 51 and the front end of the discharge track 52. The belts are trained over two sets of pulleys 93, 9 mounted on horizontal pulley-drying shafts 95 and 96, respectively, which are journalcd in bearings on the opposite side walls of the On he forward pulleydriving saft 95 there is also mounted the driving pulley 56 which drives the belt 55 by means of which the rollers 53 of the loading tracl: 51 are stated. As seen Fi 7, the upper sides of he belts 91 and 92 are upported on the underside by upper walls 97 o -elt 98 on both ides of the table drbiihg chamber, the lower 'des of said belt passing th"ough the interior of enclosures formed by sail belt guards and being protected thereby.

seen in the drawing, all the driving parts of the rotary table that are liable to injury by sand particles are completely enclosed in the table drive chamber 75, only the sleeve '72 extending through an opening in the upper wall of the chamber, and the horizontal driving shaft 86 through the bearing members in the side walls of the chamber. Entrance of sand or grit into the chamber through the openings through which said members move is prevented by felt washers a unit from the casing 21 by loosening screws 102 by means of which the table driv'ng chamber is sec= ed to cross 1.03 extending between the walls of the casing. In order to facilitate such ready removal and, in general, the mounting of the mechanism, the horizontal driving shaft 86 of the table mechanism is made in three sections, the central section extending from the table driving chamber 75' eing secured to the two side sections by means of couplings 10 i. After loosening the ecu-p11 104 and the screws 104' thereof, together with the screws 102, the entire table driving mechanism may be removed as a unit.

Disposed in front of the table 61 in the space between the two transfer belts 91, 92, there is mounted a transfer platform 110 by means of which the work objects are tran ferred one by one from the loading track 51 to the transfer belts l, 92. The individual objects are all arranged o flat bases 111, preferably rectangular and uniform. These bases for instance, be in the form of rectangular boards or pallets and may have a member 112 for holding the object 113 to be worked on in suitable position for carrying out the blasting operation.

The transfer platform 110 is made in the form of a rectangular sheet metal plate having a downwardly bent front edge 115 and an upwardly bent weight 120 tending t e platform 110 ll tilt for orally in the direction toward the load section when the table is r ised and the platform will tilt rearwardly when the table is lowered.

in the drawings Fig. 5 shows the transfer platform 11o forwardly tilted position, the table being at that moment in raised position; and Fig. 5 shows the transfer platform in the rearwardly til ed position, the table being at that mo nt in the lowered position. It will be noted that when the tra sfer platform is in the rearwardly tl ted posi on, as shown in Fig. 5, the front edge 115 thereof is raised somewhat above the plane at which the working objects arrive so th the forward edge stops the bases and preve--. them from moving farther on to the transfer belts 91 and 92. When the transfer platform 116 is tilted to th forward position, as shown in Fig. 6, the forward edge of the platform moves down and permits the base of the next we ng object waiting at the rear end of the loa ing section to be advanced forward on to-the transfer bolts 91 and 92. In this position the transfer platform 1.16 is substantially in the plane of the transfer belts and so arranged that the object with its base c 1 forward until the base reaches the raised rear edge 116 of the transfer platform, as shown in 6.

length of the base 111 is such that when its rear edge abuts against the rear edge 116 of the p atform 110, the front edge of the base projects in front of the front edg 115 of the platform. The width of the base is such that the sides thereof extend beyond the platform and come in contact with the transfer belts 91, 92 so to be frictionally carried thereby moved in the direction from the loading section 2 to the discharge section If, now, the platform in the position as shown in Fig. 6, with e held thereon against the rear edge 6. is tilted to rearward position, the rear edge 6 drops below the level of the two transfer belts 91. 2. As a result, the base with the object led thereby is taken up by the belts and l away the platform while the raised of the platform prevents the base is next in line from moving in the meanwhile on to the platform.

rfoirnance of the blasting operation. platform 131 comprises a substangnlar meial plate extending between r sides of the transfer belts, the being cut out n the center to provide an opening 122 for the table '71. The platform plate 131 mounted on a framework formed of two bars 133 which are pivoted on a rod 135 mounted in front of the table 'll-between'the two belt guards 98. 1 The bars '133 have balancing arms 1-6 which extend forwardly on the other side of the pivoted rod 135: Balancing weights 137 are slidably adjustable on said'balancing arms. Accordingly, the table platform -131 is free to swing around the'pivoting axis formed by the rod 135, and-by shifting; the balancing weight 137 the position of the'platforrn 131 may be readily adjusted. This balancing weight 137 is normally so adjusted as to give the table'platform 131 a tendency to tilt upwardly, as shown in Fig. 6, the upward movement of the table platform limited, and being just sufficient to slightly assist in carrying the weight of the base 111 and the object mounted thereon, when said base rests upon the two transfer bolts 91, 92 on both sides of the table platform'131, in the position shown in Fig. 5.

.;t the rear end of the table platform 131 there is -ounted a stop member 140 consisting of an angle iron extending between the two rear ends of the supporting bars 133 and pivoted therein by of a rod 141. The pivoting point of the stop member 1 16 so chosen that when said member freely suspended, it assumes the position shown in'Fig. 6 so that its stopping edge-142 slightly projects above the plane of the platform 131. As a result, the base 111, on being moved by the transfer belts from the'transfer platform 110 to the table platform -131, will catch against the upwardly projecting stopping edge 142 of the stop member 140 and swing said memher to the upright position, as shown in Fig. 5, the ilting movement of said stop member being limited by a stop bar 1 14. Upon lifting of the base 111 by thetable '71 the stop member 140 is released and swings back into the position in which it is shown in Fig. 6 so that upon the subsequent descent of the base member, the upper edge 142 of the stop member 140 is-tilied downwardly to the position shown by dotted lines 145 and the transfer belts are free to carry the base with the object mounted thereon rearwardly toward the discharge track 52 of the machine.

The several mechanisms are actuated by an electric motor 151 mounted on the top of the machine casing. The n1ot0r'151 drives through a reduction gear 152 a sprocket chain 153 which in turndrives a shaft 154, the shaft 154 likewise being mounted on top of the casing. The motion of the shaft 15% is transmitted through second sprocket chain drive 155 to a second driving shaft 155 mounted on the top of themachine casing. From the second driving shaft 156 motion is transmitted through a third sprocket chain drive 15'? mounted on the side wall of the casing to the shaft 96 carrying the driving pulleys 94 of the two transfer belts 91 and 92. sprocket chain drive 159 mounted on the other side of the casing transmits the motion of the belt driving shaft 95 to the table driving shaft 86. The sprocket chain drives are all mounted outside of the spaces within the main casing 21 and may be protected by suitable enclosures or guards 160.

Within the blasting chamber 33 are arranged several sets of blasting nozzles. In the embodimerit of the invention illustrated in the drawings, three such sets 161, 162, 163 are used. As shown in Fig. 7, one nozzle set 161 is mounted adjacent to the left side wall of the blasting chamber, the other nozzle set- 162 is mounted ad- A fourth T.

jacent to the right side wall of the chamber, and 15d the third nozzle set 163 is mounted adjacent to the top wall of the chamber. Each set of nozzles 161 to 163 comprises an H-shaped nozzle support 165 made of pipe sections with four nozzles 166 mounted at the four ends of the H-shaped supporting members. The individual nozzles 166 are shown in Fig. 13. Each nozzle comprises a suction chamber 167 terminating into a nozzle tube 168 through which the blast of sand is discharged. A compressed air discharge tube 169 has an air discharge nozzle 1'70 extending through the suction chamber 167 into the nozzle tube 168. In operation, the suction chamber 167 is connected to a container with sand and a stream of air is discharged through the air discharge nozzle 1'70. This produces a strong suction in the nozzle 168 and sucks up the sand which is then discharged by the strong stream of air from the air discharge nozzle 1'70.

The nozzle supporting member 165 of each set of suction nozzles is carried upon a swinging arm 1'71 mounted outside of the machine casing, there being three such swuiging arms, one for each of the nozzle sets. The several arms 1'71 are made of pipe sections and have bent end members 1'72 extending into the blast chamber through arcuate openings 1'73. The individual nozzle supporting members 165 are mounted on the ends of the arm members 1'72 projecting into the blasting chamber. The hollow swinging arms 1'71 with the hollow nozzle supports 165 serve to supply compressed air to the individual blast nozzles, and for this reason the compressed air discharge tubes 169 of each nozzle are in direct communication with the hollow spaces of the nozzle supports 165.

A swinging or oscillatory movement is imparted to the two swinging arms 1'71 on the sides of the casing through crank arms 1'75 mounted on the ends of the first shaft 154, the rotary motion of the cranks being transformed into reciprocating movement imparted to the arms 1'71 by means of connecting rods 1'76. The two cranks 1'75 on the two ends of the shaft 154 are offset against each other 186 degrees so that when one nozzle set is in its uppermost position, the other nozzle set is in its lowermost position, as shown in Fig. '7. The swinging arm 1'71 which is mounted on the top of the casing for actuating the third nozzle set 163 is oscillated by means of a crank arm 1'77 and connecting rod 1'78 which are driven by an auxiliary shaft 1'79 that is rotated by the motor 151.

The crank arm 1'7'7 for oscillating the top nozzle set 163 is so adjusted that the top nozzle set 163 is directed towards the point of the object to be blasted which is outside of the range of action of the other two nozzles. For instance, as shown in Fig. '7, while the nozzle set 161 is directed to the left upper end of the object to be blasted and the nozzle set 162 to the lower right-hand end of the obiect to be blasted, the upper nozzle 163 is at that moment directed to the upper righthand end of the object to be blasted. In the further course of their movements, the left-hand nozzle 161 goes downwardly, the right-hand nozzle set 162 goes upwardly and the upper nozzle set 163 goes from right to left, and this staggered movement of the several nozzle sets is cyclically repeated throu hout the operation of the machine, In other words, the several nozzle sets follow each other in sequence so as to uniformly cover the entire area that is to be blasted, the motion of the several sets being dephased against each other. Compressed air for the nozzle is supplied through a compressed air supply line 181 leading into a moisture separator 182 mounted on the machine casing. From the air outlet of the moisture separator, the air is supplied to the swinging arms 1'71 by means of flexible hose connections 183.

Sand is supplied to the suction chambers 167 of the several blast nozzles by means of a flexible sand suction hose 184 connecting the suction chambers with sand suction nozzles 1S5 mounted at the lower ends of the hopper sections 30 and 31 at the bottom of the blasting chamber. Such suction nozzle is shown in detail in Figs. 11 and 12. It comprises a feed box 186 mounted directly under an outlet opening 187 near the lower end of the hopper, a slide 188 serving to adjust the width of the opening. Extending through the length of the feed box there is a pipe 190 slotted at its top so as to permit entrance of sand into the pipe. The front end of the pipe 190 has connected thereto the sand suction hose 184. From the rear end of the pipe 190 there extends into the center thereof an air inlet pipe 191 having an outwardly flared end portion which forms a closure over the end of said pipe.

With the foregoing arrangement, the suction produced in the blast nozzle by the air streaming from the air discharge nozzle induces a stream of air through the air inlet pipe 191, which stream of air picks up the sand particles and carries them through the hose 184 into the suction chamher 167 and the pipe 168 of the blast nozzle.

As seen in the drawings, the several nozzles of each set are so mounted on the nozzle holder that the blast issuing from the several nozzles converge but do not quite meet in a space where the object to be blasted is mounted so as to prcduce a cyclonic or whirling movement of the sand particles, thereby securing a high blasting efiiciency.

The hoppers and 46 at the bottom of the loading and discharge sections 0. the machine are intended to collect sand particles getting into said sections from the blasting chamber. The sand or grits collecting in said hoppers 45 and 46 are transferred over into the main hopper sections 30 and 31 at the bottom of the blasting chamber by means of suction nozzles 195 and hose sections 196 leading from said suction nozzle to said hopper sections 30 and 31, as shown in Fig. 3. The suction nozzles 195 comprises an outer tubular chamber 197 connected to the bottom of the hoppers, and an air discharge nozzle 198 opening in the direction of the transfer hose 196, the air discharge nozzle being connected to a compressed air supply pipe 199. The jet of air blowing through the discharge nozzle 198 sucks up the sand accumulating at the bottom of the end hoppers 45, 46 and carries it over into the main hopper sections 30 and 31.

Protection is also provided against sand particles escaping from the blasting chamber through the arcuate openings 1'73 for the nozzle arm end members 1'72. To this end there is mounted at the arm end on the inner side of the opening a flexible baffle sheet 201, as shown in Fig. '7, the bafile sheet being of such width and length that it covers the adjacent opening throughout the entire range of the movement of the corresponding nozzle set.

In order to initially load the machine with the blasting sand or other blasting material, a door 202 is provided in the side wall of the blasting section. Through the opening of this door a quantity of sand or other blasting material may be charged into the two hopper sections 30, 31 at the bottom of the blasting chamber.

In order to operate the machine, the driving motor 151 is energized and compressed air is a mitted to the several nozzle 1'71 and therethrough to the blast nozzles 165. As a result, a blast of sand is sent the three sets blast nozzles 1, 162, 153. The rotation of the motor 151 causand, as a result thereof, the blast sa the nozzles is not confined to one sing but covers a defined area of the space above t rotasy table 71 in which the object to be blasted is held for the blasting operation.

are so arr blasts of th to secure thorough blasting action.

ber 33.

Simultaneously therewith the table driving shaft 85 causes table '71 to rotate in a continuous movement, the cam 77 causing the table to move at the same time up down We sud-.1

during each rotation. This move sent of the table is so timed through the shape of the cam surface '26 the table sleeve 72, that the table moves in elevated position throughout substantially the of the ion. and is lowered only for urin which the object 1n tn table and a n w and down movedent the be e 7 swinging movement of the transfer pl: 10 by means of which the objects to l sted transferred by one 51 onto the transfer belts 91, 92 for movement into the space above the table '71.

several curtains 35, 36, 4.2 and 43 over the openings into individual chambers or sections of the casing are down, so that each chamber is substantially closed against the other chamber and separated therefrom. t the same time the suction nozzles 195 at the bottom of the hoppers of the loading and discharge sections exercise a continuous suction or exhausting action in these spaces and carry away dust, sand or grit particles that may get from the blasting space 33 into either one of said sections.

With the machine so operating, a row or series of objects to be blasted or worked upon are delivinto the loading opening 11 of the loading section of the machine. The individual objects a rolled into the machine through said opening either by hand or mechanically. Upon moving the object to be blasted through the opening 41 or o the t 'aclc 51, the yieldable curtain 12 recedes p rmitting the object to enter. The rotating rollers 53 on tl loading track up the object and start moving it forward the blasting chamber, the curtain 12 dropping back over the entran opening ll as soon as the object has passed therethrougn. In this way one object after another loaded into the entrance section and carried forward in a row on tne loading track 51.

moving forward on the loading track each object passes through the opening 38 in the forward wall of the hopper bounding the blasting section and is carried until the base of the object catches against the forward edge 115 of the transplatforni 110. This position of the platform corresponds to the lower position of the rotary table 71, as shown in Fig. 5. In the course of its rthor rotation, the rotary table 71 is raised by ct the cam 77 and at the same time s 11a is tilted forwardly to a; s1 ion shown in Fig. 6. The forward edge 3'15 the transfer platform 110 sets free the base 2. is l w carried forward onto the trans- 19 the action of the rollers 53 objects on the rollers, and by the t"ansfer platform, being in the position by its rear edge 116 the fort, which is held in this posi- 71 is rotated in the raised posithe rotary table Afte 71 reaches the point of its periphery where it is lowered over the carn surface depression. This downwal mov ment of the table 71 causes the transfer platform 110 to tilt into the position shown in Fig. 5. The transfer belts 91, 92 thereupon grip the object held until then on the transfer rm 11c and move it forward over the now lowered rear edge 116 of the platform. The object is carri d forward to the space above the platform 131 and the table 71, while the next f-. lowing object is still held in front of the transfer platform by the now raised forward edge 115.

entire period of time while Upon being carried forward onto the transfer platform and rotary table '71, the rear end of the object to be worked upon catches against the edge 142 of the stopping member 1 10, bringing it tothe upright position shown in Fig. 5, in which position the object is held against further mov ment. This transfer of the object from the transfer platform no to the table platform 131 takes place dining the short period of time while the rotary table is in the lowered position. Immediately upon accomplished transfer, the table is slightly raised by the cam 77, lifting the object to be worked upon together with its base 111 within the space exposed to the action of the blast nozzle. The rotation of the table with the object carried thereby is continued. thus rotating with the table 77 the blast nozzles swing over their prescribed path so that at the end of the complete revolution thus performed by the object the entire surface thereof has been covered by the strong blast issuing from the nozzles.

This composite movement of the blast nozzles relatively to the objects to be blasted secures a. scanning of the entire surface of the object to be blasted by the blasting stream and results in While the object is very efficient and thorough blasting action. At 35 the end of the rotation of the object on the table 71 in its elevated position, as shown in Fig. 6, the table '71 is lowered, and the base 111 with the object descends upon the table platform 131, tilting stopping member to a horizontal position so that the transfer belts are free to carry the object toward the discharge track 52 in the discharge section 26 of the casin The finished objects arriving one after another on the discharge tract: 52 of the discharge section of the machine member may then be removed through the discharge opening 43, either manually or by a transfer mechanism. The foregoing sequence of operations is repeated on each successive working object loaded into the machine, the machine being thus capable of handling very large quantitles of work without any manual assistance. In going through the machine from chamber to chamber, the individual objects pass readily through the yieldable curtains 35, 36, separating the chambers, these curtains returning immediately to their vertical positions as soon as the objects have passed therethroug--. In this way the strong blast of sand and grit issuing from the blast nozzles in the blasting chamber 33 is substantially confined to the blasting chamber, the sand and grit dropping down into the hoppers 30, 31 from which they are sucked up through the suction pipes 184 leading to the individual nozzles.

As shown in Fig. 3, the forward and rear walls 27 of the hopper bounding the blast section 25 of the machine are inclined, forming a large hopper so that any particles of sand or grit escaping from the blasting chamber 33 are returned into the two hopper sections 30, 31 at the bottom of the blasting chamber. The sand and grit particles which get into the loading section 24 or discharge section 26, through the openings 38,

39 of the main central hopper, are collected in the auxiliary hoppers 4.5, 46 of said sections and carried back into the central hopper sections 30, 31 by the conduits 196.

In the arrangement described above, all the moving parts are efficiently protected against the very strong destructive action of the blast and grits. Thus, the driving mechanisms for the several shafts are placed outside of the casing compartments that are in communication with the blast chamber. The driving mechanism for the rotary table is housed in a completely closed chamber. All the openings through which moving shafts enter into the space exposed to the blast or flying grit particles are protected through washers such as shown at 101 in Fig. '7. The parts which move within the space exposed to flying sand particles, such as the belts and the driving shafts therefor and the track rollers, are all by nature of such character that they are not liable to injury or damage by the grit particles. In

- this way a combination of protected and unprotected moving parts is obtained which secures efficient automatic action of the blasting machine in the way described. hereinbefore, the

, several parts being so related and of such design as to eliminate damage and necessity for frequent repair by reason of the destructive action of the dust and grits flying in the several spaces.

Since the operation of the machine is entirely automatic, 2. much stronger sand blast can be used than in the case where the blasting must be done partially manually, the strength of the blast in the latter case being limited by the necessity for protecting the operators against the flying grit dust caused by too strong a blast.

As seen from the foregoing, we provide by our invention a progressive automatic sand blasting machine in which the individual working objects are carried into the blasting chambers on substantially uniform bases. Chambers are provided both in front and at the outlet side from the blasting chamber and the objects blasted are automatically moved from the entrance chamber into the blasting chamber for performing the blasting operation, and are then removed from the blasting chamber into the outlet chamber upon completion of the blasting operation. The several chambers are separated and closed against each other so as to divert flying sand particles and grits and avoid their entrance into the inlet and outlet chambers of the machine.

Grit and dust particles which nevertheless enter into the inlet or outlet chamber of the machine are collected and are sucked away and returned back into the main collecting hoppers at the bottom of the blasting chamber.

The blasting apparatus is so correlated with the movement of the individual objects through the machine that each object is subjected to a thorough blasting over its entire surface by causing the sand blast to move in a composite movement against the object blasted so as to cover the entire space in which the object is held in blasting position in the blasting chamber. A special mechanism for individually delivering the working objects into the blasting chamber and for discharging it therefrom is so arranged as to be substantially fool-proof and remain in operative condition notwithstanding the tremendous blast action in the space where it mounted. The two platforms 110 and 131 of this mechanism are so arranged that they assist the belts in holding up the object that is to be blasted during the periods when the object is held by said platforms stationary on the belts, so as to reduce the friction incident to the movement of the belts past the object.

By adjusting the relative movement of the nozzles and the turn table, the period during which any portion of the working object is exposed to the blast may be readily regulated. The arrangement may be also so modified that the rotary table 71 performs several revolutions before being lowered for discharging the finished object and loading thereon the next object to be worked upon. In such case, a second sleeve is mounted within the sleeve which carries the gear 75, the second sleeve being also rotated but at a slower rate and being provided with a cam surface 76 by means of which the turn table is lifted up and down, such arrangement being shown in Fig. 14.

The machine of our invention is not confined to the use of sand but may be used with any other blasting material, such as steel grits and the like. The broad features of our invention are likewise not limited to the particular details of mechanism employed in the machine described hereinabove but many other forms of the invention will suggest themselves to those skilled in the art. It is accordingly desired that the ap pended claims be given a broad construction commensurate with the scope of the invention within the art.

We claim:

1. In a blasting machine, a blasting chamber,

a loading chamber, a discharge chamber, a loading track in said loading chamber, a discharge track in said discharge chamber, a movable support in said blast chamber for receiving and holding the objects during the blasting operation, means for controlling the movement of objects from said loading track to said support, said controlling means being controlled by said support, means for transferring said objects from said loading track to said support, nozzle means in said chamber for producing a blast of grits against the object on said support, and means for producing a relative movement between said support and said nozzle means.

2. In a blasting machine, a blasting chamber,

a horizontal table support in said blasting chamber, a loading track and a discharge track communicating with said chamber and arranged at opposite sides of said support, means for producing a progressive movement of a series of objects said to be blasted from said loading track onto the support in said-blastin chamber nd from said support to said discharge trach, nozzle means for producing a blast of grits against the object on said support, and means for producing a movement of said support in said blasting chamber relative to said nozzle means and also to the direction of movement or" the objects from said loading track to said discharge track.

3. in a blasting machine, a blasting chamber, a support in said blasting chambe', a loading track and a discharge track communicating with said chamber, means for producing a progressive movement of a series or" objects to be blasted from said loading track onto the support 'n said blasting chamber and from said support to said discharge track, nozzle for producing a bl Lab of grits against the object on said support,

progressive rnovei l nt, and means for g the rate of said progressive movement response to said periodical movement. 4 I- a as g roach re, a blasting chamber,

in said blasting chamber, a loading track and a dis harge track communicating with chamber, in -s for producing a progressive "nent of a series of objects to be blasted from said loading track onto the support in said blast ing chamber and from support to said discharge track, nozzle means for producing a blast of grits against the object on said support, means producing a movement of said support relative to tie direction oi said progressive movement, and means for contro ng the rate or" said progressive movement in response to said periodical rnovenent.

5. In a clash -g machine, a blasting chamber, a vertically movable support in said chan for holding a working object to be nozzle means for producing a blast of grits directed against object on said support, means for producing a eriodical movement of said support said chamber, means for loading and U11,- loading working objects from said support in response to said periodical nio einent.

6. In blasting machine, a blasting chamber, a loading track and a discharge track connected to said chamber, a vertically movable support in said chamber for an object to be blasted in said chamber, nozzle means for directing a blast of grits against said object on said support, means for rotating said support, means controlled by support for effecting the progressive loading or objects to be blasted from said loading track to said support, and means controlled by said support for effecting the progressive unloading of the blasted objects from said support to said discharge track.

7. In a blasting machine, a blast chamber, a support within chamber for the object to be blasted, loading means at one side of said support, unloading means at the opposite side or" said support, means for producin a blast of grits against an object on said support, mean for effecting pre .eterznined relative rnoveinen between said support and sa' grit-blastin means, rneans for transferring he object from load lg mean to in ca means, timed with relation to the relative movebetween said spport and the grit-blasting means for effecting movement by the transfer means of the object from the loading means to said support at the beginning of said predeter- Cf (I mined movement, and means for efiecting movement by the transfer of the object from said support to the unload. nieans upon the termination of said predetermined movement.

ect ng blast 1 support, transsted pe indie-ally also by for transtracl; to

movable supp "-I i "er to the discharge track, ransfer platform bee super platrnovement of said support for tilting he er p' tfciin relatively said conveying means, operative to feed the ooiect on ort, and responto the movement of ssupport to render rat-ire to transfer the t ioin the support to the discharge vable support for trans- .n the loading track to Mom the latte to the inovable f charge tbetwee' tb a discharge track and disposed at port, means between said tiltable transfer platform and said movable support responsive to the movement of said support for tilting the transfer platform relatively to said conveyor belts, whereby to render the latter operative to feed the objects to said support, means for blasting the object on said support, and means responsive to the movement of said support to render the conveyor belts operative to transfer the blasted object from the support to the discharge track.

12. In a blasting machine, a blast chamber, a loading chamber, a discharge chamber, a loading track in said loading chamber, a discharge track in said discharge chamber, a movable support in said blast chamber for receiving and holding the objects during the blasting operation, conveying means arranged between said loading track and said discharge track for transferring said objects from the loading track to the movable support and from the latter to the discharge track, a tiltable transfer platform between the loading track and the movable support, means between said tiltable transfer platform and said movable support responsive to the movement of said support for tilting the transfer platform relatively to said conveying means, whereby to render the latter operative to feed the objects to said support, means for blasting the object on said support, and a tilting member arrange adjacent the said movable support and responsive to the movement of said support at a predetermined point in such movement to render the conveying means operative to transfer the blasted object from the support to the discharge track.

13. In a blasting machine, a blast chamber, a loading chamber, a discharge chamber, a loading track in said loading chamber, a discharge track in said discharge chamber, a movable support in said blast chamber for receiving and holding the objects during the blasting operation, conveyor belts arranged between said loading track and said discharge track and disposed at opposite sides of said movable support for transferring said objects from the loading track to the movable support and from the latter to the discharge track, a tiltable transfer platform between the loading track and the movable support, means between said tiltable transfer platform and said movable support responsive to the movement of said support for tilting the transfer platform relatively to said conveyor belts, whereby to render the latter operative to feed the objects to said support, means for blasting the object on said support, and a tilting member arranged adjacent the said movable support and responsive to the movement of said support at a predetermined point in such movement to render the conveyor belts operative to transfer the blasted object from the support to the discharge track.

14. In a blasting machine, a blast chamber, a loading chamber, a discharge chamber, a loading track in said loading chamber, a discharge track in said discharge chamber, a movable support in said blast chamber for receiving and holding the objects during the blasting operation, conveying means arranged between said loading track and said discharge track for transferring said objects from the loading track to the movable support and from the latter to the discharge track, a tiltable transfer platform etween the loading track and the movable support, means between said tiltable transfer platform and said movable support responsive to the movement of said support for tilting the transfer platform relatively to said conveying means, whereby to render the latter operative to feed the objects to said support, mean for blasting the object on said support, a table platform arranged adjacent the said movable support, and a tilting stop member carried by said table platform and serving to arrest the movement of the objects to be blasted at a predetermined point in the movement of the support, whereby to position the objects on the movable support, said tilting stop member also

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