CA1097080A - Sandblasting machine and method for finishing moulded or castpieces - Google Patents
Sandblasting machine and method for finishing moulded or castpiecesInfo
- Publication number
- CA1097080A CA1097080A CA305,481A CA305481A CA1097080A CA 1097080 A CA1097080 A CA 1097080A CA 305481 A CA305481 A CA 305481A CA 1097080 A CA1097080 A CA 1097080A
- Authority
- CA
- Canada
- Prior art keywords
- pieces
- conveyor tube
- tube
- sandblasting
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C3/00—Abrasive blasting machines or devices; Plants
- B24C3/18—Abrasive blasting machines or devices; Plants essentially provided with means for moving workpieces into different working positions
- B24C3/26—Abrasive blasting machines or devices; Plants essentially provided with means for moving workpieces into different working positions the work being supported by barrel cages, i.e. tumblers; Gimbal mountings therefor
- B24C3/266—Abrasive blasting machines or devices; Plants essentially provided with means for moving workpieces into different working positions the work being supported by barrel cages, i.e. tumblers; Gimbal mountings therefor for continuously travelling workpieces
Abstract
"SANDBLASTING MACHINE AND METHOD FOR
FINISHING MOULDED OR CAST PIECES"
ABSTRACT OF THE DISCLOSURE
A sandblasting method for finishing moulded or cast pieces, in which the pieces to be sandblasted are rotated in front of a sandblasting jet directed such that it strikes the pieces in a direction trasverse to the feed direction thereof.A machine for carrying out the method comprises a conduit in which the pieces being processed move forward under gravity by rolling and a sand-blasting jet which attacks the interior of the conduit transversely.
FINISHING MOULDED OR CAST PIECES"
ABSTRACT OF THE DISCLOSURE
A sandblasting method for finishing moulded or cast pieces, in which the pieces to be sandblasted are rotated in front of a sandblasting jet directed such that it strikes the pieces in a direction trasverse to the feed direction thereof.A machine for carrying out the method comprises a conduit in which the pieces being processed move forward under gravity by rolling and a sand-blasting jet which attacks the interior of the conduit transversely.
Description
10~70t~0 This invention relates to a sandblasting machine and method for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics.
The practice of finishing, or more generally surface-treating articles under production by means of sand-blasting is very widespread in modern technology. It is used on all metal pieces to be painted, enamelled, metallized, etc., on metal pieces produced by casting or moulding to re ve burrs, on plastics pieces to be painted or metallized to improve adhesion, and on moulded plastics parts for trimming and finishing, to cite just some examples related to the field of the invention, which, although having been developed to satisfy specific problems of resin products, is not limited to these and is extended in its application to related sectors such as those stated.
The moulding, die-casting and injection moulding of resin or plastics pieces has been developed particularly in the electrotechnical field for economical reasons and for the ease of incorporating metal parts in the mouldings, which ;20 ~ ~ would be impossible in the case of the more esteemed a~nd costly ceramic insulant material. Thus objects have been ; produced by moulding which are increasingly complicated and in their final stages of assembly, or at least in very advanced ,, ~ ~ , .
stages, such as single or multi-6tage electrical switches and ; commutators. The great economy of such production is due to the complete automation and high productivity rate attained, ~ such that the intervention of direct labour has nearly dis-;~ appeared. The pieces produced in this manner require only surface finishing to remove casting or moulding burrs.
Initially, this operation was carried out by an operator using a jet of sand in a box, and wearing a protective ~ k.
The practice of finishing, or more generally surface-treating articles under production by means of sand-blasting is very widespread in modern technology. It is used on all metal pieces to be painted, enamelled, metallized, etc., on metal pieces produced by casting or moulding to re ve burrs, on plastics pieces to be painted or metallized to improve adhesion, and on moulded plastics parts for trimming and finishing, to cite just some examples related to the field of the invention, which, although having been developed to satisfy specific problems of resin products, is not limited to these and is extended in its application to related sectors such as those stated.
The moulding, die-casting and injection moulding of resin or plastics pieces has been developed particularly in the electrotechnical field for economical reasons and for the ease of incorporating metal parts in the mouldings, which ;20 ~ ~ would be impossible in the case of the more esteemed a~nd costly ceramic insulant material. Thus objects have been ; produced by moulding which are increasingly complicated and in their final stages of assembly, or at least in very advanced ,, ~ ~ , .
stages, such as single or multi-6tage electrical switches and ; commutators. The great economy of such production is due to the complete automation and high productivity rate attained, ~ such that the intervention of direct labour has nearly dis-;~ appeared. The pieces produced in this manner require only surface finishing to remove casting or moulding burrs.
Initially, this operation was carried out by an operator using a jet of sand in a box, and wearing a protective ~ k.
- 2 -;
10970~0 However, this manual operation, besides giving rise to some criticism and preoccupation from the health aspect, is out of step with the whole economy of the production process.
Thus completely automatic sandblasting was necessarily brought in.
The method used at the present time consists of disposing a load of pieces in a cavity or cradle on to which a wide jet of sand or grit is directed while the load is con-tinuously agitated or turned in such a manner that the entire surface of each piece is exposed to the jet in various posi-tions. ~his method has proved valid from the point of view of working efficiency and economy in the amount it contributes to the cost of each sandblasted piece, but has a serious drawback which is intrinsic to its system and cannot be eliminated unless the system itself is changed, namely that the pieces inevitably collide with each other as they are turned, and if the pieces comprise delicate projections such as is the case with switches and the like, these can become damaged or broken, and this is reflected in an excessive number of production rejects. To obviate this serious drawback, it has been attempted to pass the objects to be sandblasted one by one in front of the sand jet in various positions, either by passing the piece se~eral times in different positions in front of the same jet, or by passing the piece in front of different jets disposed in different positions. To pass the piece again in a different position, the conveyor, belt, chain or wire carrying the objects is returned in front of the jet, but this allows only two passes with two fixed positions. More simply, the pieces are loaded several times in different positions on .
~ _ 3 _ 109~7()80 the same conveyor belt passing in front of the fixed jet.
This requires an operator for the loading and unloading, An attempt has also been made to load the pieces on to rotatable supports on the conveyor. This can be successful in the case of large costly pieces, but would be too expensive for common pieces. Thus the problem of sandblasting pieces having a shape even slightly complicated has not yet found a general satisfactory olution.
The general object of the present invention is therefore to obviate the drawbacks of the aforesaid sand-blasting methods.
One particular object of the invention is a con-tinuous sandblasting method which enables the individual pieces to be sandblasted practically in all directions.
A further particular object is a sandblasting machine which enables the new method to be carried out.
A further particular object is a device for a sand-- blasting machine which enables a piece to be presented in a single pass in front of a jet of sand or grit while making it assume all the required positions, without any danger of impact damaging to the method, These and further objeats have been attained accordiny to the invention by a sandblasting method for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-sett1ng plastics, wherein the pieces to be sandblasted are made to roll in front of a sandblasting jet, individually in a single pass, within a reticulated portion of a conduit.
To carry out the method according to the invention 10970~30 there is provided a sandblasting machine for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics, comprising a conduit in which the pieces to be processed are caused to move forward under gravity by rolling, and a sandblasting jet which is directed into the interior of the conduit transversely In accordance with a particular embodiment of the invention, a sandblasting machine for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics, comprises a rotatable conveyor tube forthe pieces to be sandblasted, said conveyor tube having its axis i~clined downwardly in the feeding direction of said pieces thereby to feed by gravity said pieces therethrough, - : -said conveyor tube having at least one aperture in an inter-mediate portion thereof, blasting jet generating means having blades directing the sandblast jet towards said aperture in a direction transverse to said axis, characterized in that said aperture extends over the entire circumference of said intermediate portion of said conveyor tube, said intermediate portion comprises an open mesh structure covering said aperture and the machine includes rotatable supports allowing full continuous rotation of said conveyor tube about its axis and drive means for imparting a full continuous rotation to said conveyor tube about its axis, thereby to impart a random rolling to said pieces both in a circumferential and axial direction of the conveyor tube.
The characteristics and advantages of the invention will be apparent from the detailed description of a preferred embodiment given by way of example, with reference to the accompanying drawings, in which:
, B
Fig. 1 is a perspective view of a sandblasting machine for carrying out the method according to the invention, Fig. 2 is a view in the direction II of Figure 1, Fig. 3 is an axial section in elevation of the device for single pass sandblasting according to the invention, and Fig. 4 is an axial section through a turbine which generates the sand jet.
Reference will now be made in particular to Figures 1 and 2 which show a machine or installation for carrying out the invention, indicated overall by the reference numeral 1.
It consists of a housing 2 with an upper support surface 3 from which projects a stepped part 4, which is connected by way of a connector 5 to a suction fan 6 comprising a tor 6'.
The housing 2 is supported on four feet 7, between which there extends a hopper 8 in the form of a lower appendix to the housing 2. A unit formed from an electric ' ~:
, ~ ~
.~
- 5a -B
motor 10 and a centrifugal sand jet turbine 11 is fixed on to the surface 3 by way of a base 9. A vertical screw conveyor tube 12 is connected to the discharge mouth of the hopper 8 (Fig. 2) to gravity-feed the turbine or turbo-ejector 11 with sand in closed cycle. The screw inside the tube of the con-veyor 12 is driven by an electric motor 13. The housing 2 is traversed, in a plane normal to the axis-of the turbine 11, by a tubular conduit 14 (Fig. 3) which represents the feeder and single-pass conveyor for the pieces to be sandblasted. The turbine 11 feeds its sand jet towards the interior of the housing, along the axis of the conveyor 14 as described here-inafter. A door 15 enables the interior of the housing 2 to be inspected and maintained.
Figure 3 shows an axial section, in a vertical plane, through the entire portion of the conveyor 14 which traverses the housing 2, together with part of the two conveyor projec~
tions thereof. The conveyor tube 14 is disposed with its axis inclined downwards from left to right in Fig. 3, to ensure that the conveyed pieces move forward while rolling, when the tube is rotated. It is mounted in the opposing walls of the housing 2 by way of two rotatable supports 16, each consti-tuted by a flange 17 and backing flange 18 which clamp between them the edges of the perforated wall of the housing 2, and house between them three rolling bearings 19 distributed peripherally 120 apart, on which the tube 14 rolls by way of a sleeve 20 rigid with the tube. A coupling covering 21 is provided to protect the bearing from the sand.
The sleeve 20 of the upstream coupling is also used for transmitting rotary motion to the tube, generated by an electric motor 22 and transmitted to the tube via a reduction gear 23 and belt 24. The conveyor tube 14 is interrupted over ~ "
: , - . : . .................... . - .
. , .: .
lOg7~0 at least the entire portion corresponding to the sand jet, indicated orientatively by the dashed lines running from the turbine 11, of which the impeller is indicated diagrammatic-ally in Fig 3.
Over this portion, the tube is replaced by a cylindri-cal basket or cage 25, of the same diameter as the tube 14, and mounted in alignment therewith by means of two end flanges 26.
Advantageously, the basket or cage portion 25 has wide meshes compatible with the dimensions of the pieces to he sandblasted, and fairly thin wall wires or bars. To obtain the necessary mechanical connection for maintaining alignment and transmit-ting motion between the two portions of the tube 14, a stirrup coupling is provided externally and consists of two flanges 27, each disposed at the mouth of a respective portion of tube 14, and facing the corresponding flange 26 The flanges 27 are joined firmly together by two external stirrups 28 disposed 180 apart. This mechanical coupling enables the basket 25 to be easily replaced without moving the tube 14.
~ Figure 4 shows the turbine or turbo-ejector 11, which although representing the essential member of the sandblasting installation does not form an actual part of the invention, and is shown because it has been designed and constructed for use in the preferred embodiment of the invention. The turbine 11 comprises essentially a casing 30 fixed to the base 9.
With the casing 30 there is rigid a sleeve support 31 in which the turbine shaft 32 is supported on two support bearings 33 and a thrust bearing 34, and is driven by a pulley 35 with three races. The impeller carried by the shaft comprises two sets of blades, namely a central set in the form of teeth on a rotating distributor 36, and a set in the form of centrifugal injection blades 37. The teeth of the rotating distributor 36 rotate between the teeth of a fixed distributor 38, the teeth ''', ~
1097()80 of which are opposite and external to the former. rrhe turbine 11 is disposed with its axis horizontal and its centrifugal discharge port pointing downwards, as indicated by the arrow.
An elbow connector 39 gravity-feeds the sand axially to the turbine, by receiving it from the screw conveyor 12. A nozzle injector tube 40 feeds water under controlled conditions into the stream of sand to moisten and lubricate it.
rrhe description of operation of-the installation will begin with the turbine heretofore described. rrhe sand reaches its central region where the rotating distributor 36 feeds it by way of the fixed distributor 38 uniformly on to the blades of the impeller 37, which project it into a volute delivery path defined by the casing 30, as in the case of a centrifugal pump As shown in Fig. 3, the wide jet of sand or grit is directed and centred on the basket 25 of the tubu-lar conveyor 14. The pieces to be sandblasted, for example of thermo-setting resin and not shown, are fed continuously into the conveyor 14 one behind the other, the minimum dis-tance apart without touching each other. The speed of rot-ation of the tube and its slope are chosen such that for agiven width and efficiency of the sand jet, each piece rotates about itself a number of times and remains exposed for the time necessary for its entire surface to be sufficiently sandblasted. The rotation of the tube helps the piece to roll downwards along the tube. rrhe jet also aids the transverse rolling of the piece, which therefore passes through all possible positions. As the pieces follow closely behind each - other, the jet is very well utilized, and as it is proportioned uniformly over each piece and over the entire surface of each piece, the exposure thereof can be reduced to the necessary minimum. rrhis is in contrast to the sandblasting of pieces which are rotated in a heap, because in this case there is a 1~)97(~80 high statistical influence, which means that a factor even higher than 2 would have to be exceeded in order to obtain a high probability of sandblasting all the pieces, and even then there are always pieces which are sanded to an excessive or insufficient degree. The fan 6 maintains a certain vacuum in the housing 2, to prevent dust leaving through the tube 14.
The air is then purified or fed to a stack. It is advisable to make the basket 25 and stirrups 28 of abrasion-resistant material, or better still make them coated, for example enamelled, or covered with special anti-abrasive resins, or coated with rubber specially resistant to sandblasting. The tube 14 is also preferably coated, for example with plastics, so that there is no danger of the pieces suffering damaging impact during rolling. It should be noted that this ideal operation has been obtained by means of a structure and a mechanical system which are extremely simple and of low cost.
The entire movement is provided by a small geared motor unit and a direct belt drive. Thus, relative to equivalent previous installations, perfect processing with elimination of all the causes of rejects in this processing stage is obtained, to-gether with greater productivity, completely auto~atic con-tinuous operation, and lower installation cost. It is apparent that the concepts described can be embodied in different forms without leaving the scope of protection of the invention.
For example, even though of less merit, the turbine sander could be replaced by any air jet sander, and in all cases the jet could point in any other sideways direction or from below, and the tube could be made to vibrate instead of rotate.
~ :.
10970~0 However, this manual operation, besides giving rise to some criticism and preoccupation from the health aspect, is out of step with the whole economy of the production process.
Thus completely automatic sandblasting was necessarily brought in.
The method used at the present time consists of disposing a load of pieces in a cavity or cradle on to which a wide jet of sand or grit is directed while the load is con-tinuously agitated or turned in such a manner that the entire surface of each piece is exposed to the jet in various posi-tions. ~his method has proved valid from the point of view of working efficiency and economy in the amount it contributes to the cost of each sandblasted piece, but has a serious drawback which is intrinsic to its system and cannot be eliminated unless the system itself is changed, namely that the pieces inevitably collide with each other as they are turned, and if the pieces comprise delicate projections such as is the case with switches and the like, these can become damaged or broken, and this is reflected in an excessive number of production rejects. To obviate this serious drawback, it has been attempted to pass the objects to be sandblasted one by one in front of the sand jet in various positions, either by passing the piece se~eral times in different positions in front of the same jet, or by passing the piece in front of different jets disposed in different positions. To pass the piece again in a different position, the conveyor, belt, chain or wire carrying the objects is returned in front of the jet, but this allows only two passes with two fixed positions. More simply, the pieces are loaded several times in different positions on .
~ _ 3 _ 109~7()80 the same conveyor belt passing in front of the fixed jet.
This requires an operator for the loading and unloading, An attempt has also been made to load the pieces on to rotatable supports on the conveyor. This can be successful in the case of large costly pieces, but would be too expensive for common pieces. Thus the problem of sandblasting pieces having a shape even slightly complicated has not yet found a general satisfactory olution.
The general object of the present invention is therefore to obviate the drawbacks of the aforesaid sand-blasting methods.
One particular object of the invention is a con-tinuous sandblasting method which enables the individual pieces to be sandblasted practically in all directions.
A further particular object is a sandblasting machine which enables the new method to be carried out.
A further particular object is a device for a sand-- blasting machine which enables a piece to be presented in a single pass in front of a jet of sand or grit while making it assume all the required positions, without any danger of impact damaging to the method, These and further objeats have been attained accordiny to the invention by a sandblasting method for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-sett1ng plastics, wherein the pieces to be sandblasted are made to roll in front of a sandblasting jet, individually in a single pass, within a reticulated portion of a conduit.
To carry out the method according to the invention 10970~30 there is provided a sandblasting machine for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics, comprising a conduit in which the pieces to be processed are caused to move forward under gravity by rolling, and a sandblasting jet which is directed into the interior of the conduit transversely In accordance with a particular embodiment of the invention, a sandblasting machine for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics, comprises a rotatable conveyor tube forthe pieces to be sandblasted, said conveyor tube having its axis i~clined downwardly in the feeding direction of said pieces thereby to feed by gravity said pieces therethrough, - : -said conveyor tube having at least one aperture in an inter-mediate portion thereof, blasting jet generating means having blades directing the sandblast jet towards said aperture in a direction transverse to said axis, characterized in that said aperture extends over the entire circumference of said intermediate portion of said conveyor tube, said intermediate portion comprises an open mesh structure covering said aperture and the machine includes rotatable supports allowing full continuous rotation of said conveyor tube about its axis and drive means for imparting a full continuous rotation to said conveyor tube about its axis, thereby to impart a random rolling to said pieces both in a circumferential and axial direction of the conveyor tube.
The characteristics and advantages of the invention will be apparent from the detailed description of a preferred embodiment given by way of example, with reference to the accompanying drawings, in which:
, B
Fig. 1 is a perspective view of a sandblasting machine for carrying out the method according to the invention, Fig. 2 is a view in the direction II of Figure 1, Fig. 3 is an axial section in elevation of the device for single pass sandblasting according to the invention, and Fig. 4 is an axial section through a turbine which generates the sand jet.
Reference will now be made in particular to Figures 1 and 2 which show a machine or installation for carrying out the invention, indicated overall by the reference numeral 1.
It consists of a housing 2 with an upper support surface 3 from which projects a stepped part 4, which is connected by way of a connector 5 to a suction fan 6 comprising a tor 6'.
The housing 2 is supported on four feet 7, between which there extends a hopper 8 in the form of a lower appendix to the housing 2. A unit formed from an electric ' ~:
, ~ ~
.~
- 5a -B
motor 10 and a centrifugal sand jet turbine 11 is fixed on to the surface 3 by way of a base 9. A vertical screw conveyor tube 12 is connected to the discharge mouth of the hopper 8 (Fig. 2) to gravity-feed the turbine or turbo-ejector 11 with sand in closed cycle. The screw inside the tube of the con-veyor 12 is driven by an electric motor 13. The housing 2 is traversed, in a plane normal to the axis-of the turbine 11, by a tubular conduit 14 (Fig. 3) which represents the feeder and single-pass conveyor for the pieces to be sandblasted. The turbine 11 feeds its sand jet towards the interior of the housing, along the axis of the conveyor 14 as described here-inafter. A door 15 enables the interior of the housing 2 to be inspected and maintained.
Figure 3 shows an axial section, in a vertical plane, through the entire portion of the conveyor 14 which traverses the housing 2, together with part of the two conveyor projec~
tions thereof. The conveyor tube 14 is disposed with its axis inclined downwards from left to right in Fig. 3, to ensure that the conveyed pieces move forward while rolling, when the tube is rotated. It is mounted in the opposing walls of the housing 2 by way of two rotatable supports 16, each consti-tuted by a flange 17 and backing flange 18 which clamp between them the edges of the perforated wall of the housing 2, and house between them three rolling bearings 19 distributed peripherally 120 apart, on which the tube 14 rolls by way of a sleeve 20 rigid with the tube. A coupling covering 21 is provided to protect the bearing from the sand.
The sleeve 20 of the upstream coupling is also used for transmitting rotary motion to the tube, generated by an electric motor 22 and transmitted to the tube via a reduction gear 23 and belt 24. The conveyor tube 14 is interrupted over ~ "
: , - . : . .................... . - .
. , .: .
lOg7~0 at least the entire portion corresponding to the sand jet, indicated orientatively by the dashed lines running from the turbine 11, of which the impeller is indicated diagrammatic-ally in Fig 3.
Over this portion, the tube is replaced by a cylindri-cal basket or cage 25, of the same diameter as the tube 14, and mounted in alignment therewith by means of two end flanges 26.
Advantageously, the basket or cage portion 25 has wide meshes compatible with the dimensions of the pieces to he sandblasted, and fairly thin wall wires or bars. To obtain the necessary mechanical connection for maintaining alignment and transmit-ting motion between the two portions of the tube 14, a stirrup coupling is provided externally and consists of two flanges 27, each disposed at the mouth of a respective portion of tube 14, and facing the corresponding flange 26 The flanges 27 are joined firmly together by two external stirrups 28 disposed 180 apart. This mechanical coupling enables the basket 25 to be easily replaced without moving the tube 14.
~ Figure 4 shows the turbine or turbo-ejector 11, which although representing the essential member of the sandblasting installation does not form an actual part of the invention, and is shown because it has been designed and constructed for use in the preferred embodiment of the invention. The turbine 11 comprises essentially a casing 30 fixed to the base 9.
With the casing 30 there is rigid a sleeve support 31 in which the turbine shaft 32 is supported on two support bearings 33 and a thrust bearing 34, and is driven by a pulley 35 with three races. The impeller carried by the shaft comprises two sets of blades, namely a central set in the form of teeth on a rotating distributor 36, and a set in the form of centrifugal injection blades 37. The teeth of the rotating distributor 36 rotate between the teeth of a fixed distributor 38, the teeth ''', ~
1097()80 of which are opposite and external to the former. rrhe turbine 11 is disposed with its axis horizontal and its centrifugal discharge port pointing downwards, as indicated by the arrow.
An elbow connector 39 gravity-feeds the sand axially to the turbine, by receiving it from the screw conveyor 12. A nozzle injector tube 40 feeds water under controlled conditions into the stream of sand to moisten and lubricate it.
rrhe description of operation of-the installation will begin with the turbine heretofore described. rrhe sand reaches its central region where the rotating distributor 36 feeds it by way of the fixed distributor 38 uniformly on to the blades of the impeller 37, which project it into a volute delivery path defined by the casing 30, as in the case of a centrifugal pump As shown in Fig. 3, the wide jet of sand or grit is directed and centred on the basket 25 of the tubu-lar conveyor 14. The pieces to be sandblasted, for example of thermo-setting resin and not shown, are fed continuously into the conveyor 14 one behind the other, the minimum dis-tance apart without touching each other. The speed of rot-ation of the tube and its slope are chosen such that for agiven width and efficiency of the sand jet, each piece rotates about itself a number of times and remains exposed for the time necessary for its entire surface to be sufficiently sandblasted. The rotation of the tube helps the piece to roll downwards along the tube. rrhe jet also aids the transverse rolling of the piece, which therefore passes through all possible positions. As the pieces follow closely behind each - other, the jet is very well utilized, and as it is proportioned uniformly over each piece and over the entire surface of each piece, the exposure thereof can be reduced to the necessary minimum. rrhis is in contrast to the sandblasting of pieces which are rotated in a heap, because in this case there is a 1~)97(~80 high statistical influence, which means that a factor even higher than 2 would have to be exceeded in order to obtain a high probability of sandblasting all the pieces, and even then there are always pieces which are sanded to an excessive or insufficient degree. The fan 6 maintains a certain vacuum in the housing 2, to prevent dust leaving through the tube 14.
The air is then purified or fed to a stack. It is advisable to make the basket 25 and stirrups 28 of abrasion-resistant material, or better still make them coated, for example enamelled, or covered with special anti-abrasive resins, or coated with rubber specially resistant to sandblasting. The tube 14 is also preferably coated, for example with plastics, so that there is no danger of the pieces suffering damaging impact during rolling. It should be noted that this ideal operation has been obtained by means of a structure and a mechanical system which are extremely simple and of low cost.
The entire movement is provided by a small geared motor unit and a direct belt drive. Thus, relative to equivalent previous installations, perfect processing with elimination of all the causes of rejects in this processing stage is obtained, to-gether with greater productivity, completely auto~atic con-tinuous operation, and lower installation cost. It is apparent that the concepts described can be embodied in different forms without leaving the scope of protection of the invention.
For example, even though of less merit, the turbine sander could be replaced by any air jet sander, and in all cases the jet could point in any other sideways direction or from below, and the tube could be made to vibrate instead of rotate.
~ :.
Claims (2)
1. A sandblasting machine for finishing moulded or cast pieces, particularly for trimming mouldings of thermo-setting plastics, comprising a rotatable conveyor tube for the pieces to be sandblasted, said conveyor tube having its axis inclined downwardly in the feeding direction of said pieces thereby to feed by gravity said pieces therethrough, said conveyor tube having at least one aperture in an inter-mediate portion thereof, blasting jet generating means having blades directing the sandblast jet towards said aperture in a direction transverse to said axis, characterized in that said aperture extends over the entire circumference of said intermediate portion of said conveyor tube, said intermediate portion comprises an open mesh structure covering said aperture and the machine includes rotatable supports allowing full con-tinuous rotation of said conveyor tube about its axis and drive means for imparting a full continuous rotation to said conveyor tube about its axis, thereby to impart a random rolling to said pieces both in a circumferential and axial direction of the conveyor tube.
2. A sandblasting machine according to claim 1, wherein said intermediate portion is in the form of a tubular basket structure having means for removably fixing said basket in alignment with said conveyor tube, said fixing means compris-ing flange means on opposite ends of said intermediate portion and stirrup means in engagement with said conveyor tube and said flange means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT2507577A IT1080956B (en) | 1977-06-24 | 1977-06-24 | SANDBLASTING MACHINE AND PROCEDURE IN PARTICULAR FOR DEBURRING PRINTS IN RESIN |
| IT25075A/77 | 1977-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1097080A true CA1097080A (en) | 1981-03-10 |
Family
ID=11215625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA305,481A Expired CA1097080A (en) | 1977-06-24 | 1978-06-14 | Sandblasting machine and method for finishing moulded or castpieces |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5411164A (en) |
| BE (1) | BE868265A (en) |
| CA (1) | CA1097080A (en) |
| CH (1) | CH630551A5 (en) |
| DE (1) | DE2826156A1 (en) |
| FR (1) | FR2395109A1 (en) |
| GB (1) | GB1599359A (en) |
| IT (1) | IT1080956B (en) |
| NL (1) | NL7806604A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5748161A (en) * | 1980-09-08 | 1982-03-19 | Canon Inc | Electronic interpreter |
| CN112571299B (en) * | 2020-12-09 | 2022-07-22 | 全球能源互联网欧洲研究院 | Sand blasting device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE109648C (en) * | ||||
| US702040A (en) * | 1901-09-25 | 1902-06-10 | Benjamin C Tilghman Jr | Sand-blast tumbling-barrel. |
| FR1524696A (en) * | 1967-05-26 | 1968-05-10 | Pangborn Corp | Continuous cleaning device |
| FR1532145A (en) * | 1967-07-25 | 1968-07-05 | Wheelabrator Corp | Method and apparatus for continuous treatment of the surface of objects |
| US3626641A (en) * | 1969-08-13 | 1971-12-14 | Carborundum Co | Continuous cleaning apparatus |
| CH502164A (en) * | 1970-01-23 | 1971-01-31 | Fischer Ag Georg | Process for the continuous surface treatment of workpieces and a centrifugal blast machine for carrying out the process |
| CA942064A (en) * | 1970-08-20 | 1974-02-19 | James H. Carpenter | Workpiece treating apparatus |
| US3728822A (en) * | 1971-02-02 | 1973-04-24 | Wheelabrator Frye Inc | Apparatus for handling parts |
| DE2454866A1 (en) * | 1974-11-20 | 1976-05-26 | Berger Maschf Gmbh | SPIN BLASTING SYSTEM FOR CLEANING PROFILED WORKPIECES |
-
1977
- 1977-06-24 IT IT2507577A patent/IT1080956B/en active
-
1978
- 1978-05-31 GB GB2551578A patent/GB1599359A/en not_active Expired
- 1978-06-08 CH CH627078A patent/CH630551A5/en not_active IP Right Cessation
- 1978-06-13 FR FR7818324A patent/FR2395109A1/en active Granted
- 1978-06-14 CA CA305,481A patent/CA1097080A/en not_active Expired
- 1978-06-15 DE DE19782826156 patent/DE2826156A1/en not_active Ceased
- 1978-06-19 JP JP7331778A patent/JPS5411164A/en active Pending
- 1978-06-19 NL NL7806604A patent/NL7806604A/en not_active Application Discontinuation
- 1978-06-20 BE BE188685A patent/BE868265A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5411164A (en) | 1979-01-27 |
| IT1080956B (en) | 1985-05-16 |
| GB1599359A (en) | 1981-09-30 |
| NL7806604A (en) | 1978-12-28 |
| BE868265A (en) | 1978-10-16 |
| CH630551A5 (en) | 1982-06-30 |
| DE2826156A1 (en) | 1979-01-11 |
| FR2395109B1 (en) | 1981-02-13 |
| FR2395109A1 (en) | 1979-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |