CA2050000A1 - Mortar gun - Google Patents
Mortar gunInfo
- Publication number
- CA2050000A1 CA2050000A1 CA 2050000 CA2050000A CA2050000A1 CA 2050000 A1 CA2050000 A1 CA 2050000A1 CA 2050000 CA2050000 CA 2050000 CA 2050000 A CA2050000 A CA 2050000A CA 2050000 A1 CA2050000 A1 CA 2050000A1
- Authority
- CA
- Canada
- Prior art keywords
- mortar
- nozzle
- wall
- cylinder
- hopper
- 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.)
- Abandoned
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- Coating Apparatus (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a mortar gun which comprises a substantially vertical hopper adapted to contain mortar and having a front wall, a rear wall and a substantially horizontal bottom wall. A cylinder projects forwardly from the front wall of the hopper adjacent the bottom of the front wall.
A conically tapering nozzle extends integrally and forwardly on the cylinder. A worm feed screw rotatably lies along the bottom wall of the hopper from the back wall of the hopper and projects within the cylinder until it reaches the tapered nozzle. The screw has a central axis and a thread integrally mounted on the central shaft. An helicoidally twisted and relatively flat plate of stiff material extends integrally from the thread of the screw into the nozzle. The helicoidally twisted flat plate rotatably lies adjacent the corresponding inner wall of the conical nozzle.
The helicoidal flat plate thus defines an unobstructed conical axial passageway leading to a discharge aperture of the front end of the conical tapered nozzle. Upon rotation of the screw, the mortar in the hopper is pushed through the cylinder towards the discharge nozzle by the feed screw. The mortar in the nozzle is pushed through the passageway by the mortar leaving the cylinder and by the helicoidal flat plate which frictionally transmits a forward thrust to the mortar. The plate also scrapres the inner wall of the mortar to prevent the mortar from sticking to it.
The present invention relates to a mortar gun which comprises a substantially vertical hopper adapted to contain mortar and having a front wall, a rear wall and a substantially horizontal bottom wall. A cylinder projects forwardly from the front wall of the hopper adjacent the bottom of the front wall.
A conically tapering nozzle extends integrally and forwardly on the cylinder. A worm feed screw rotatably lies along the bottom wall of the hopper from the back wall of the hopper and projects within the cylinder until it reaches the tapered nozzle. The screw has a central axis and a thread integrally mounted on the central shaft. An helicoidally twisted and relatively flat plate of stiff material extends integrally from the thread of the screw into the nozzle. The helicoidally twisted flat plate rotatably lies adjacent the corresponding inner wall of the conical nozzle.
The helicoidal flat plate thus defines an unobstructed conical axial passageway leading to a discharge aperture of the front end of the conical tapered nozzle. Upon rotation of the screw, the mortar in the hopper is pushed through the cylinder towards the discharge nozzle by the feed screw. The mortar in the nozzle is pushed through the passageway by the mortar leaving the cylinder and by the helicoidal flat plate which frictionally transmits a forward thrust to the mortar. The plate also scrapres the inner wall of the mortar to prevent the mortar from sticking to it.
Description
_ITLE_OF_THE_INVE2~TION:
MORTAR GUN
BACKGROUND OF THE; INVENTION-___________________________, Field of the invention:
This invention relates to a mortar gun and more particularly to mortar gun specifically adapted to dispense feed mortar having a thick and viscous consistancy.
Prior art:
A search amongst prior art has re~ealed a pertinent patent, namely U.S. patent 2,694,509 which discl.oses a mortar gun somewhat similar to the present invention.
The previously patented mortar gun is provided with an horizontally projecting circular nozzle ~referred to by numeral 16 and a worm feed screw referred to by numeral 17. The worm feed screw 17 is adapted to push the mortar out through the front section of the nozzle 16. The screw has a forward tapered end which projects into the tapered front extension 20 of the front wall l4, terminating just short oE the nozzle 16. The shaft 22 of the screw 16 has a t~apered section 21 which tapers down.
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It is stated in column l, lines 80 and 81, and column 2, lines 1-3, of U.S. patent 2,694,509, that this construction ;:~
insures the even feeding of the stiff mortar eliminating air `:~
spaces which ehe stiff mortar:would otherwise l.eave in giving the mortar its final solid push.
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from the construction of the forward end of the worm feed screw.
Firstly, the shaft 22 of the worm screw 17 is very dif~icult to manufacture according to the specifications disclo-sed in the patent. Indeed, a shaft which tapers down almost to a point having a screw also tapering down mounted on it requires a lengthy and costly manufacturing process.
Secondly, since the tapered end 21 of the screw 17 terminates just short of the nozzle, a portion of the last thread o~ the screw is always obstructing a section of the d;scharge aperture. Although this constraint might seem trivial when relatively flu;d mortar ;s used, the obstruct;on of a portion of the nozzle as proven to be d;sastrous when relat;vely th;ck and viscous fluid is used.
Thicker mortar ;s used pr;ncipally ;n Northern reg;ons where the regulations frequently require that the mortar, to be applied, be able to ma;ntain a ball-shape configuration without sagging.
When such a firm and dense mortar ;s used to feed sect;on of the discharge aperture obstructed by a worm feed screw, as is the case with the mortar gun disclosed in U.S.
patent No. 2,694,509 the mortar is temporarily compressed, squaezing out the water and causing a segregation wh;ch seperates the sand particles. The segregated sand part;cles have a tendency to get squeezed by the thread of the screw and lock the 9crew, thus d;sturbing the operat;on of the gun and possibly causing damages to the structure of the gun.
Thirdly, when th;cker mortar is used, ;t has a tendency to dry up along the peripheral wall of the tapered section 20 of the nozzle 16 since the flow is slower around the : ' :
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per;phery than in the middle of the discharge sect;on. The drying up of the mortar along the wall causes an obstruction which tends to compress and thus segregate the mortar again possibly causing damages to the gun.
SUMMARY OF THE INVENTION
_________________________ According~y, the present invention relates to mortar gun which will circumvent the above mentioned d;sadvantages. The improved mortar gun comprises a substantially vertical hopper adapted to contain mortar and having a front wall, a rear wall and a substantially horizontal bottom wall. A cylinder projects ~rwflrdly from the front wall of the hopper adjacent the bottom of the front wall. A conically tapering nozzle extends inte-grally and forwardly on the cylinder. A feed screw rotatably lies along the bottom wall of the hopper from the back wall of the hopper and projects within the cylinder until it reaches the tapered nozzle. The screw has a central shaft and a thread integrally mounted on the central shaft.
An helicoidally twisted and relatively flat plate of ~ti~f materisl extends integrally from the thread of the screw into the nozzle. The helicoidally twisted flat plate rotatably lies adjacent the corresponding inner wall of the conical nozzle.
~he helicoidal flat plate thus defines an unobstructed conical sx;al passageway leading to a discharge aperture of the front end of the conical tapered nozzle. Upon rotation of the screw, the mortar in the hopper is pushed through the cylinder towards the discharge nozzle by the feed screw. The mortar in the nozzle is pushed through the passageway by the mortar leaving the cylinder and by the helicoidal flat plate which frictionally transmits a forward thrust to the mortar. The plste also scrapes the inner ;
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wall of the nozzle to prevent the mortar from sticking to it.
The helicoidal flat plate thus adapted to give the mortar its fina] push towards the discharge open;ng without obstructing the latter. It also prevents the mortar in the less rapid flow adjacent the inner wall of the conical nozzle from stick;ng to it. This particular construction is also relatively inexpensive to manufacture since the helicoidal f]at plate is manufactured independently and then simply welded to the existing thread on the feeder screw.
BRIEF DESCRIPTION OF THE DRAWINGS: -_ _ ___ __ _ ._ _ __ _ ___ __ __ _ _ _ ___ _ Figure 1 is an elevation view of a mortar gun embodying tbe invent;on;
Figure 2 is a partial frontal view of the mortar gun taken along arrow 2 of figure 1;
Figure 2a is a frontal view of the conical screw according to the invention;
Figure 3 is a longitudinal cross-sectional view of the frontal end of the mortar gun taken along arrows 3-3 of figure 2;
Figure 4 is a partial view of a wall of brlck with mortar of the type dispensed by the invention linking the bricks;
Figure 5 is a transversal cross-sectional view taken along arrows 5-5 of Eigure l;
Figure 6 is a frontal view of the discharge nozzle;
Figure 7 is a side view of the discharge nozzle;
Figure 8 is a longitudinal cross-sectional view taken along arrows 8-8 of figure 5 and illustrating the vibrating :
mechanism; and Figure 9 i.s a top cross-sectional view taken along arFows 9-9 of figure 5 also illustrating the vibrating mechanism.
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DETAILED DESCl~IPTION OF THE PREFERl~ED EMBODIMENT:
_________ _______ _________ ___._________ Re~erring to figure 1, there is shown a mortar gun lO
embodying the invention. The mortar gun 10 has a rearwardly inclined upper body 12. As illustrated more specifically in f;gure 9, the upper body 12 has a pair of side walls 14, a front wall 16 and a back wall 18. The walls 12, 14, 16 and 18 define a substantially rectangular opened top referred to in figure 1 by numeral 20.
The side walls 14 taper inwardly and integrally into a trough like bottom wall 22. The bottom wall 22 and the front wflll 16 extend integrally into a substantially circular forwardly projecting cylinder 24.
As il]ustrated more specifically in figure 3, the forwardly projecting cylinder 24 is provided with a set of peripheral annular recess 26. The annular recess 26 are adapted to receive a set of corresponding retaining rings 28.
A conically tapering adaptor 30 is slidably positioned over the forwardly projecting cylinder 24. The adaptor 30 is frictionally held in place by the retaining rings 28 which are preferably made of material having elastomeric properties.
A discharge noæzle 32 is abuttingly and slidingly positioned inside the adpator 30. The discharge nozzle 32 has a substantially conical back section 34 adapted to fittingly abut against a corresponding conically tapering inner wall 36 of the adapter 30 and; a substantially truncated front section 38 characterized by two substantially oblique walls 40 defining a substantially oval dlscharge aperture 42.
The oval dlscharge apert:ure 42 is particularly suited for the application of mortar to link structural elements such as :
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the bricks 78 of figure 4 which are linked together by a set of mortar joints 80. The oval aperture 42 has preferably flat sides to sl;de between rows of bricks.
A worm feed screw 44 rotatably extends along the trough like bottom 22. The worm feed screw 44 has a shaft 46 on which i9 integra]ly mounted a thread 48. As illustrated more specifically in figure 8, the worm feed screw 44 extends integrally at its rear end in~o an annular journal plate 50. The annular plate 50 is rotatably mounted inside a corresponding race 52 provided in the back wall 18 of the hopper body 12. The annular plate 50 is provided with a recess 54 adapted to receive the frontal end of a driving shaft 56. A retaining screw 58 releasably keeps the driving shaft 56 linked to the annular plate 50.
The driving shaft 56 is connected to a motor (not shown) protectively enclosed inside a motor casing 60. The motor is controlled by a trigger switch 62.
One of the main features of the present invention resides in the use of a vibrating rod 64 illustrated more specifically in figures 5, 8 and 9. The vibrating rod 64 is Rdapted to prevent the mortar from:segregating inside the hopper body 12 and jamming the worm feed screw 44. The vibrating rod 64 is mounted inside a sleeve 66 which extends through the back wall 18 of the hopper body 12. : ~ : :
The v;brating rod 64 projects at its rear end over a .:
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v;brating wheel 68 mounted on the drivlng shaft 56. The : :~
vibrating wheel 68 has an external contour provided with protube~
rances 70~
When the drlving shaft 56 rotates, an abutting sleeve :
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72 mounted on the vibrating rod 64 follows the contour of the wheel 68 thus transforming the rotat;onal. movement of the driving sha~t 56 into a pivotal oscillating movement of the vibrating rod 64 illustrated by the dotted lines and the arrows of figure 8.
The vibrating rod 64 is adapted to pivot about the .sleeve 66 which is made of material having resilient el.astomeric properties. As illustrated more specifically in figure 9, the vibrating rod 64 when seen from the top has a zig-zag configura-tion which allows it to cover a greater area.
As stated previously, the main feature of the present invention res;des in the structure of the frontal end of the worm feed screw 44 which is modified in order to perform more efficiently and prevent the segregation of thicker mortar.
As illustrated more specifically in figure 3, the inner wall 36 of the adapter 30 tapers down conically. The diameter of the inner wall 36 is reduced from approximately one inch at the junction 74 between the forwardly projecting cylinder 74 and the adapter 32 to an approximate average diameter of 3/8 of an inch at the narrow cross-section of the discharge aperture 42.
To prevent the mortar from beiog compressed by this reduction in the flow diameter, the shaft 46 of the worm -Eeed screw 44 terminates adjacent the junction 74. The thread 48 of the worm feed screw 44 is prolonged integrally into a flat helicoidal conical screw thread 76 having no central shaft. The conical screw thread 76 ~is made of a re].atively thin~flat plate of metal rotatably positioned adjacent the inner wal]. 36 of the adapt~or 30.
The helicoidal plate 76 defines a conical passageway :
having a central axis colinear with the shaft 46 and leading to ~ .
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-8- ~ 3 the discharge aperture 42.
The thread 48 oF the screw 44 is adapted to push the mortar from the hopper 12 to the junct;on 74 between the cylinder 24 and the adaptor 30. Once the mortar reaches the adaptor 30, it is pushed both by the mortar leaving the cylinder 24 and by a frictionally transmitted helicoidal forward thrust imparted on the mortar by the plate 76.
The width represented by the letter "W" in figure 3 of the helicoidal plate 76 is thus much greater than the width "w"
of the thread 48 since the surface of contact with the mortar must be opt;mized to frict:ionaly transmit the helicoidal forward trust.
The section of the passageway defined by the conical screw thread 76 being greater than the annu].ar peripheral section defined between the periphery of the shaft 46 and an inner wa].l 47 of the cylinder, the section available for the mortar to flow through is thus increased, compensating for the tapering inner wall 36 and preventing compression of the mortar.
The conical screw thread 76 elegantly circumvents the three previously mentionned disadvantages inherent to the worm feed screw described in U.S. patent 2,694,509.
F;rstly, as mentionned earlier, the shaft of the mortar gun described in the U.S. patent 2,694,509 which tapers down to a point in order to compensate for the tapering down of the nozzle is expensive to manufacture. The con~cal screw thread of the present invention is manufactured independent].y and then simply welded to the thread 48 of the screw 44. This greatly simplifies the manufacturing proces~s thus representing a ma]or economical advantage.
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Secondly, as illu.~trated clearly in figure 2a, since the conical thread is made of a flat helicoidal .section of material which rotatably lie.s adjacent the periphery of the inner wall 36 of the adapter 30, the discharge aperture 4Z is never obstructed by any structure. With the mortar gun described in U.S. patent 2,694,509, since a conventional thread mounted on a shaft was used all the way to the locat;.on of the discharge aperture, a section of the last thread always obstructs the di~charged aperture.
Thirdly, as indicated in figure 2a, during its rotation the conical thread 76 defines a zone of friction with the inner wall 36. In this zone of friction, the mortar which has a tendency to dry up along the inner wall. is scraped from the wall and pushed into the flow of mortar. This zone of friction angularly rotates with the rotation of the helicoidal pl.ate 76.
The conical thread 76 is thus adapted to give the mortar its final push towards the discharge opening 42 without obstructing the latter and to prevent the mortar in the less ~:
rapid flow adjacent the inner WAll 36 from sticking to the wall.
To further improve the quality of the flow eæcaping through the discharge opening 42, the width W of the conical thread 76 i9 wider than the width W' of thread 48 of the worm feed ~crew 44. The wider thread thus accelerates the flow of mortar just prior to its discharge through the discharge aperture 42. ~ .
In order to maintain the rate of flowing of mortar throughout the cylindrical ;nner wall 47 and the conical inner wall 36, the volume of mortar located over the shaft 46 in one pitch of the thread 44 should be equal or greater thfln the volume through one pitch of the he].icoidal plate 76. Considering that ~:
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the helico;dal piate 76 may have more than one pitch, and is rotating in a con;cal sleeve 30, the length of successive pitches in the d;rection of the discharge nozzle increases proportionally to the tapering angle of the sleeve 30 for maintaining a constant flow throughout.
One preferred embodiment of the discharge nozzle 32 is ;llustrated in figures 6 and 7. The discharge aperture 42 is oblong with flattened sides 43 obta;ned from the tapered straight walls 40. This oblong shape allows the projected mortar to follow the jo;nts ~0 between the bricks.
Considering that the joints 80 are vertical and hori-zontal, the adaptor 30 is rotatably mounted on the cylinder 24 for selectively orienting the flattened sidewalls in the direc-tion of the vertical or horizontal joints. With the oblong discharge, the forward tip 41 of the plate 76 which is narrower and thinner, is accordingly flexible for scraping the inner wall of the front section 38 of the discharge nozz]e 32. Such a scraping operation causes the tip 4] of the plate 76 to have a zone of friction and a zone of clearance as identified in figure 2b. ~
Although described in this patent as being used in conjunction with a mortar gun, the construction of the forward end o~ the feed screw whlch comprises a flat helicoidaL thread extending integrally from the thread of a shafted worm feed screw could be used in a number of other applications. In fact, it could be used~ whenever the materisl is extruded through an aperture provided at the end of a conical nozzle. Examples of such mechan-sms includes plastic extrusion machines and dry feeders, , . . . : :
. . . : :.
MORTAR GUN
BACKGROUND OF THE; INVENTION-___________________________, Field of the invention:
This invention relates to a mortar gun and more particularly to mortar gun specifically adapted to dispense feed mortar having a thick and viscous consistancy.
Prior art:
A search amongst prior art has re~ealed a pertinent patent, namely U.S. patent 2,694,509 which discl.oses a mortar gun somewhat similar to the present invention.
The previously patented mortar gun is provided with an horizontally projecting circular nozzle ~referred to by numeral 16 and a worm feed screw referred to by numeral 17. The worm feed screw 17 is adapted to push the mortar out through the front section of the nozzle 16. The screw has a forward tapered end which projects into the tapered front extension 20 of the front wall l4, terminating just short oE the nozzle 16. The shaft 22 of the screw 16 has a t~apered section 21 which tapers down.
:"
It is stated in column l, lines 80 and 81, and column 2, lines 1-3, of U.S. patent 2,694,509, that this construction ;:~
insures the even feeding of the stiff mortar eliminating air `:~
spaces which ehe stiff mortar:would otherwise l.eave in giving the mortar its final solid push.
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from the construction of the forward end of the worm feed screw.
Firstly, the shaft 22 of the worm screw 17 is very dif~icult to manufacture according to the specifications disclo-sed in the patent. Indeed, a shaft which tapers down almost to a point having a screw also tapering down mounted on it requires a lengthy and costly manufacturing process.
Secondly, since the tapered end 21 of the screw 17 terminates just short of the nozzle, a portion of the last thread o~ the screw is always obstructing a section of the d;scharge aperture. Although this constraint might seem trivial when relatively flu;d mortar ;s used, the obstruct;on of a portion of the nozzle as proven to be d;sastrous when relat;vely th;ck and viscous fluid is used.
Thicker mortar ;s used pr;ncipally ;n Northern reg;ons where the regulations frequently require that the mortar, to be applied, be able to ma;ntain a ball-shape configuration without sagging.
When such a firm and dense mortar ;s used to feed sect;on of the discharge aperture obstructed by a worm feed screw, as is the case with the mortar gun disclosed in U.S.
patent No. 2,694,509 the mortar is temporarily compressed, squaezing out the water and causing a segregation wh;ch seperates the sand particles. The segregated sand part;cles have a tendency to get squeezed by the thread of the screw and lock the 9crew, thus d;sturbing the operat;on of the gun and possibly causing damages to the structure of the gun.
Thirdly, when th;cker mortar is used, ;t has a tendency to dry up along the peripheral wall of the tapered section 20 of the nozzle 16 since the flow is slower around the : ' :
, ~ _3_ 2 ~ a ~
per;phery than in the middle of the discharge sect;on. The drying up of the mortar along the wall causes an obstruction which tends to compress and thus segregate the mortar again possibly causing damages to the gun.
SUMMARY OF THE INVENTION
_________________________ According~y, the present invention relates to mortar gun which will circumvent the above mentioned d;sadvantages. The improved mortar gun comprises a substantially vertical hopper adapted to contain mortar and having a front wall, a rear wall and a substantially horizontal bottom wall. A cylinder projects ~rwflrdly from the front wall of the hopper adjacent the bottom of the front wall. A conically tapering nozzle extends inte-grally and forwardly on the cylinder. A feed screw rotatably lies along the bottom wall of the hopper from the back wall of the hopper and projects within the cylinder until it reaches the tapered nozzle. The screw has a central shaft and a thread integrally mounted on the central shaft.
An helicoidally twisted and relatively flat plate of ~ti~f materisl extends integrally from the thread of the screw into the nozzle. The helicoidally twisted flat plate rotatably lies adjacent the corresponding inner wall of the conical nozzle.
~he helicoidal flat plate thus defines an unobstructed conical sx;al passageway leading to a discharge aperture of the front end of the conical tapered nozzle. Upon rotation of the screw, the mortar in the hopper is pushed through the cylinder towards the discharge nozzle by the feed screw. The mortar in the nozzle is pushed through the passageway by the mortar leaving the cylinder and by the helicoidal flat plate which frictionally transmits a forward thrust to the mortar. The plste also scrapes the inner ;
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wall of the nozzle to prevent the mortar from sticking to it.
The helicoidal flat plate thus adapted to give the mortar its fina] push towards the discharge open;ng without obstructing the latter. It also prevents the mortar in the less rapid flow adjacent the inner wall of the conical nozzle from stick;ng to it. This particular construction is also relatively inexpensive to manufacture since the helicoidal f]at plate is manufactured independently and then simply welded to the existing thread on the feeder screw.
BRIEF DESCRIPTION OF THE DRAWINGS: -_ _ ___ __ _ ._ _ __ _ ___ __ __ _ _ _ ___ _ Figure 1 is an elevation view of a mortar gun embodying tbe invent;on;
Figure 2 is a partial frontal view of the mortar gun taken along arrow 2 of figure 1;
Figure 2a is a frontal view of the conical screw according to the invention;
Figure 3 is a longitudinal cross-sectional view of the frontal end of the mortar gun taken along arrows 3-3 of figure 2;
Figure 4 is a partial view of a wall of brlck with mortar of the type dispensed by the invention linking the bricks;
Figure 5 is a transversal cross-sectional view taken along arrows 5-5 of Eigure l;
Figure 6 is a frontal view of the discharge nozzle;
Figure 7 is a side view of the discharge nozzle;
Figure 8 is a longitudinal cross-sectional view taken along arrows 8-8 of figure 5 and illustrating the vibrating :
mechanism; and Figure 9 i.s a top cross-sectional view taken along arFows 9-9 of figure 5 also illustrating the vibrating mechanism.
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DETAILED DESCl~IPTION OF THE PREFERl~ED EMBODIMENT:
_________ _______ _________ ___._________ Re~erring to figure 1, there is shown a mortar gun lO
embodying the invention. The mortar gun 10 has a rearwardly inclined upper body 12. As illustrated more specifically in f;gure 9, the upper body 12 has a pair of side walls 14, a front wall 16 and a back wall 18. The walls 12, 14, 16 and 18 define a substantially rectangular opened top referred to in figure 1 by numeral 20.
The side walls 14 taper inwardly and integrally into a trough like bottom wall 22. The bottom wall 22 and the front wflll 16 extend integrally into a substantially circular forwardly projecting cylinder 24.
As il]ustrated more specifically in figure 3, the forwardly projecting cylinder 24 is provided with a set of peripheral annular recess 26. The annular recess 26 are adapted to receive a set of corresponding retaining rings 28.
A conically tapering adaptor 30 is slidably positioned over the forwardly projecting cylinder 24. The adaptor 30 is frictionally held in place by the retaining rings 28 which are preferably made of material having elastomeric properties.
A discharge noæzle 32 is abuttingly and slidingly positioned inside the adpator 30. The discharge nozzle 32 has a substantially conical back section 34 adapted to fittingly abut against a corresponding conically tapering inner wall 36 of the adapter 30 and; a substantially truncated front section 38 characterized by two substantially oblique walls 40 defining a substantially oval dlscharge aperture 42.
The oval dlscharge apert:ure 42 is particularly suited for the application of mortar to link structural elements such as :
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the bricks 78 of figure 4 which are linked together by a set of mortar joints 80. The oval aperture 42 has preferably flat sides to sl;de between rows of bricks.
A worm feed screw 44 rotatably extends along the trough like bottom 22. The worm feed screw 44 has a shaft 46 on which i9 integra]ly mounted a thread 48. As illustrated more specifically in figure 8, the worm feed screw 44 extends integrally at its rear end in~o an annular journal plate 50. The annular plate 50 is rotatably mounted inside a corresponding race 52 provided in the back wall 18 of the hopper body 12. The annular plate 50 is provided with a recess 54 adapted to receive the frontal end of a driving shaft 56. A retaining screw 58 releasably keeps the driving shaft 56 linked to the annular plate 50.
The driving shaft 56 is connected to a motor (not shown) protectively enclosed inside a motor casing 60. The motor is controlled by a trigger switch 62.
One of the main features of the present invention resides in the use of a vibrating rod 64 illustrated more specifically in figures 5, 8 and 9. The vibrating rod 64 is Rdapted to prevent the mortar from:segregating inside the hopper body 12 and jamming the worm feed screw 44. The vibrating rod 64 is mounted inside a sleeve 66 which extends through the back wall 18 of the hopper body 12. : ~ : :
The v;brating rod 64 projects at its rear end over a .:
`:
v;brating wheel 68 mounted on the drivlng shaft 56. The : :~
vibrating wheel 68 has an external contour provided with protube~
rances 70~
When the drlving shaft 56 rotates, an abutting sleeve :
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72 mounted on the vibrating rod 64 follows the contour of the wheel 68 thus transforming the rotat;onal. movement of the driving sha~t 56 into a pivotal oscillating movement of the vibrating rod 64 illustrated by the dotted lines and the arrows of figure 8.
The vibrating rod 64 is adapted to pivot about the .sleeve 66 which is made of material having resilient el.astomeric properties. As illustrated more specifically in figure 9, the vibrating rod 64 when seen from the top has a zig-zag configura-tion which allows it to cover a greater area.
As stated previously, the main feature of the present invention res;des in the structure of the frontal end of the worm feed screw 44 which is modified in order to perform more efficiently and prevent the segregation of thicker mortar.
As illustrated more specifically in figure 3, the inner wall 36 of the adapter 30 tapers down conically. The diameter of the inner wall 36 is reduced from approximately one inch at the junction 74 between the forwardly projecting cylinder 74 and the adapter 32 to an approximate average diameter of 3/8 of an inch at the narrow cross-section of the discharge aperture 42.
To prevent the mortar from beiog compressed by this reduction in the flow diameter, the shaft 46 of the worm -Eeed screw 44 terminates adjacent the junction 74. The thread 48 of the worm feed screw 44 is prolonged integrally into a flat helicoidal conical screw thread 76 having no central shaft. The conical screw thread 76 ~is made of a re].atively thin~flat plate of metal rotatably positioned adjacent the inner wal]. 36 of the adapt~or 30.
The helicoidal plate 76 defines a conical passageway :
having a central axis colinear with the shaft 46 and leading to ~ .
: ~ ' ', - ' . . ~
-8- ~ 3 the discharge aperture 42.
The thread 48 oF the screw 44 is adapted to push the mortar from the hopper 12 to the junct;on 74 between the cylinder 24 and the adaptor 30. Once the mortar reaches the adaptor 30, it is pushed both by the mortar leaving the cylinder 24 and by a frictionally transmitted helicoidal forward thrust imparted on the mortar by the plate 76.
The width represented by the letter "W" in figure 3 of the helicoidal plate 76 is thus much greater than the width "w"
of the thread 48 since the surface of contact with the mortar must be opt;mized to frict:ionaly transmit the helicoidal forward trust.
The section of the passageway defined by the conical screw thread 76 being greater than the annu].ar peripheral section defined between the periphery of the shaft 46 and an inner wa].l 47 of the cylinder, the section available for the mortar to flow through is thus increased, compensating for the tapering inner wall 36 and preventing compression of the mortar.
The conical screw thread 76 elegantly circumvents the three previously mentionned disadvantages inherent to the worm feed screw described in U.S. patent 2,694,509.
F;rstly, as mentionned earlier, the shaft of the mortar gun described in the U.S. patent 2,694,509 which tapers down to a point in order to compensate for the tapering down of the nozzle is expensive to manufacture. The con~cal screw thread of the present invention is manufactured independent].y and then simply welded to the thread 48 of the screw 44. This greatly simplifies the manufacturing proces~s thus representing a ma]or economical advantage.
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Secondly, as illu.~trated clearly in figure 2a, since the conical thread is made of a flat helicoidal .section of material which rotatably lie.s adjacent the periphery of the inner wall 36 of the adapter 30, the discharge aperture 4Z is never obstructed by any structure. With the mortar gun described in U.S. patent 2,694,509, since a conventional thread mounted on a shaft was used all the way to the locat;.on of the discharge aperture, a section of the last thread always obstructs the di~charged aperture.
Thirdly, as indicated in figure 2a, during its rotation the conical thread 76 defines a zone of friction with the inner wall 36. In this zone of friction, the mortar which has a tendency to dry up along the inner wall. is scraped from the wall and pushed into the flow of mortar. This zone of friction angularly rotates with the rotation of the helicoidal pl.ate 76.
The conical thread 76 is thus adapted to give the mortar its final push towards the discharge opening 42 without obstructing the latter and to prevent the mortar in the less ~:
rapid flow adjacent the inner WAll 36 from sticking to the wall.
To further improve the quality of the flow eæcaping through the discharge opening 42, the width W of the conical thread 76 i9 wider than the width W' of thread 48 of the worm feed ~crew 44. The wider thread thus accelerates the flow of mortar just prior to its discharge through the discharge aperture 42. ~ .
In order to maintain the rate of flowing of mortar throughout the cylindrical ;nner wall 47 and the conical inner wall 36, the volume of mortar located over the shaft 46 in one pitch of the thread 44 should be equal or greater thfln the volume through one pitch of the he].icoidal plate 76. Considering that ~:
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,. . ~ , ~ .
the helico;dal piate 76 may have more than one pitch, and is rotating in a con;cal sleeve 30, the length of successive pitches in the d;rection of the discharge nozzle increases proportionally to the tapering angle of the sleeve 30 for maintaining a constant flow throughout.
One preferred embodiment of the discharge nozzle 32 is ;llustrated in figures 6 and 7. The discharge aperture 42 is oblong with flattened sides 43 obta;ned from the tapered straight walls 40. This oblong shape allows the projected mortar to follow the jo;nts ~0 between the bricks.
Considering that the joints 80 are vertical and hori-zontal, the adaptor 30 is rotatably mounted on the cylinder 24 for selectively orienting the flattened sidewalls in the direc-tion of the vertical or horizontal joints. With the oblong discharge, the forward tip 41 of the plate 76 which is narrower and thinner, is accordingly flexible for scraping the inner wall of the front section 38 of the discharge nozz]e 32. Such a scraping operation causes the tip 4] of the plate 76 to have a zone of friction and a zone of clearance as identified in figure 2b. ~
Although described in this patent as being used in conjunction with a mortar gun, the construction of the forward end o~ the feed screw whlch comprises a flat helicoidaL thread extending integrally from the thread of a shafted worm feed screw could be used in a number of other applications. In fact, it could be used~ whenever the materisl is extruded through an aperture provided at the end of a conical nozzle. Examples of such mechan-sms includes plastic extrusion machines and dry feeders, , . . . : :
. . . : :.
Claims (8)
1-. A dispensing unit for extruding a substantially mal-leable matter through a discharge aperture, said dispensing unit comprising;
- a cylinder extending from a first end to a second end and having a relatively constant cross-section, - a feeding means adapted to feed said malleable matter to said first end of said cylinder, - a tapered nozzle having an inner wall and projecting forwardly from said second end of said cylinder, said tapered nozzle having a marginal frontal edge defining said discharge aperture, - a rotatable worm feed screw lying inside said cylinder from said first end to said second end, said feed screw having a central shaft and a thread mounted integrally on the peripehry of said central shaft, an helicoidally twisted relati-vely flat plate of stiff material extending integrally from said thread into said tapered nozzle, said flat plate being adapted to rotatably lie adjacent said inner wall of said nozzle from said second end of said cylinder to said discharge aperture, said flat plate defining an unobstructed conical passageway along a central axis colinear with said shaft and leading to said discharge aperture, whereby upon rotation, said thread of said screw is adapted to push said malleable matter from said feeding means at said first end of said cylinder to said nozzle, said malleable matter in said nozzle then being pushed through said passageway by said malleable matter leaving said second end of said cylinder and by a frictionally transmitted helicoidal forward thrust imparted on the malleable matter by said helicoi-dal plate, said plate also scraping said inner wall of said nozzle preventing said malleable matter from sticking to said inner wall of said nozzle.
- a cylinder extending from a first end to a second end and having a relatively constant cross-section, - a feeding means adapted to feed said malleable matter to said first end of said cylinder, - a tapered nozzle having an inner wall and projecting forwardly from said second end of said cylinder, said tapered nozzle having a marginal frontal edge defining said discharge aperture, - a rotatable worm feed screw lying inside said cylinder from said first end to said second end, said feed screw having a central shaft and a thread mounted integrally on the peripehry of said central shaft, an helicoidally twisted relati-vely flat plate of stiff material extending integrally from said thread into said tapered nozzle, said flat plate being adapted to rotatably lie adjacent said inner wall of said nozzle from said second end of said cylinder to said discharge aperture, said flat plate defining an unobstructed conical passageway along a central axis colinear with said shaft and leading to said discharge aperture, whereby upon rotation, said thread of said screw is adapted to push said malleable matter from said feeding means at said first end of said cylinder to said nozzle, said malleable matter in said nozzle then being pushed through said passageway by said malleable matter leaving said second end of said cylinder and by a frictionally transmitted helicoidal forward thrust imparted on the malleable matter by said helicoi-dal plate, said plate also scraping said inner wall of said nozzle preventing said malleable matter from sticking to said inner wall of said nozzle.
2-. A dispensing unit as recited in claim 1, wherein the pitch of the helicoidal plate is adapted to produce a flow of malleable matter at least equal to the flow produce by one pitch of the worm screw.
3-. A dispensing unit as recited in claim 2, wherein the worm screw has at least two consecutive pitches, the second pitch adjacent the discharge aperture being longer than the first pitch and substantially inversely proportional to the ratio of the decreasing volume of the tapered nozzle.
4-. A portable mortar gun for dispensing mortar comprising:
- a substantially vertical hopper adapted to contain mortar having a front wall, a rear wall and a substantially horizontal bottom wall, a cylinder projecting forwardly from said front wall of said hopper adjacent the bottom of said front wall, a conical nozzle extending integrally and forwardly from said cylinder, a worm feed screw rotatably lying along said bottom wall of said hopper from said back wall of said hopper and protecting within said cylinder until it reaches said tapered nozzle, said screw having a central shaft and a thread integrally mounted on said central shaft, an helicoidally twisted relatively flat plate of material extending integrally from said thread into said nozzle, said plate rotatably lying adjacent said correspon-ding inner wall of said conical nozzle, said plate defining an axial unobstructed conical passageway leading to a discharged aperture at said front end of said conical nozzle, whereby upon rotation of said screw, said mortar on said hopper is pushed through said cylinder towards said discharge nozzle by said feed screw, said mortar in said nozzle being pushed through said passageway by said mortar leaving said cylinder and by said flat plate which frictionally transmits a forward thrust to said mortar, said plate also scraping said inner wall of said nozzle to prevent said mortar from sticking.
- a substantially vertical hopper adapted to contain mortar having a front wall, a rear wall and a substantially horizontal bottom wall, a cylinder projecting forwardly from said front wall of said hopper adjacent the bottom of said front wall, a conical nozzle extending integrally and forwardly from said cylinder, a worm feed screw rotatably lying along said bottom wall of said hopper from said back wall of said hopper and protecting within said cylinder until it reaches said tapered nozzle, said screw having a central shaft and a thread integrally mounted on said central shaft, an helicoidally twisted relatively flat plate of material extending integrally from said thread into said nozzle, said plate rotatably lying adjacent said correspon-ding inner wall of said conical nozzle, said plate defining an axial unobstructed conical passageway leading to a discharged aperture at said front end of said conical nozzle, whereby upon rotation of said screw, said mortar on said hopper is pushed through said cylinder towards said discharge nozzle by said feed screw, said mortar in said nozzle being pushed through said passageway by said mortar leaving said cylinder and by said flat plate which frictionally transmits a forward thrust to said mortar, said plate also scraping said inner wall of said nozzle to prevent said mortar from sticking.
5-. A mortar gun as recited in claim 4, wherein said worm feed screw is rotatably linked to a driving shaft and wherein said driving shaft is connected to a motor controlled by a trigger switch.
6-. A mortar gun as recited in claim 5, wherein said hopper body has a vibrating rod mounted inside a flexible sleeve which extends through said back wall of said hopper body, said vibrating rod projecting at its rear end over a vibrating reel mounted on said driving shaft, said vibrating wheel having an external contour provided with a set of protuberances, whereby when said driving shaft rotates said abutting sleeve mounted on said vibrating rod follows the contour of said wheel thus transferring the rotational movement of said driving shaft into a pivotal oscilating movement of the vibrating rod inside said hopper.
7-. A mortar gun as recited in claim 1, wherein the discharge nozzle has an oblong discharge aperture with flattened sidewalls.
8-. A mortar gun as recited in claim 7, comprising an aperture for maintaining said discharge nozzle on said cylinder and means for rotating sais adaptor about said cylinder for angularly orienting said discharge aperture.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2050000 CA2050000A1 (en) | 1991-08-27 | 1991-08-27 | Mortar gun |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2050000 CA2050000A1 (en) | 1991-08-27 | 1991-08-27 | Mortar gun |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050000A1 true CA2050000A1 (en) | 1993-02-28 |
Family
ID=4148254
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2050000 Abandoned CA2050000A1 (en) | 1991-08-27 | 1991-08-27 | Mortar gun |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2050000A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113530161A (en) * | 2020-04-20 | 2021-10-22 | 广东博智林机器人有限公司 | Coating device and coating robot |
-
1991
- 1991-08-27 CA CA 2050000 patent/CA2050000A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113530161A (en) * | 2020-04-20 | 2021-10-22 | 广东博智林机器人有限公司 | Coating device and coating robot |
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