CA1122133A - Air cushion chute - Google Patents
Air cushion chuteInfo
- Publication number
- CA1122133A CA1122133A CA000356324A CA356324A CA1122133A CA 1122133 A CA1122133 A CA 1122133A CA 000356324 A CA000356324 A CA 000356324A CA 356324 A CA356324 A CA 356324A CA 1122133 A CA1122133 A CA 1122133A
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- chute
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Abstract
ABSTRACT OF THE DISCLOSURE
A vertical extending, uniform cross sectional, air impervious chute is open at its opposite ends and shaped to conform to the shape of the articles to be transported from an upper station to a lower station, so that by maintaining an article in the lower end of the chute to seal the lower end of the chute, other articles may be dropped into the chute so that they will pup air ahead of them to build up air pressure between moving articles and down-stream articles. As a result, falling articles will decrease in acceleration to zero acceleration after they are dropped to a midpoint of their fall as the velocity increases from zero to a maximum, and thereafter the trapped air ahead of them will cause an increasing deceleration and a corresponding decreasing velocity until such falling article gently comes to rest due to the inter-position of a high pressure air cushion onto a down-stream stationary article. Automatic article sensors may be used to prevent the removal of the last article from the chute so as to maintain the chute seal, particularly when interlocked with a power transfer device, and further sensors may be provided at the entrance of the chute to indicate when the chute is full for the control of an automatic article feeding device. The chute may be used to transport articles between different levels, or to vertically store articles in a space saving manner for a multiple article picker system.
A vertical extending, uniform cross sectional, air impervious chute is open at its opposite ends and shaped to conform to the shape of the articles to be transported from an upper station to a lower station, so that by maintaining an article in the lower end of the chute to seal the lower end of the chute, other articles may be dropped into the chute so that they will pup air ahead of them to build up air pressure between moving articles and down-stream articles. As a result, falling articles will decrease in acceleration to zero acceleration after they are dropped to a midpoint of their fall as the velocity increases from zero to a maximum, and thereafter the trapped air ahead of them will cause an increasing deceleration and a corresponding decreasing velocity until such falling article gently comes to rest due to the inter-position of a high pressure air cushion onto a down-stream stationary article. Automatic article sensors may be used to prevent the removal of the last article from the chute so as to maintain the chute seal, particularly when interlocked with a power transfer device, and further sensors may be provided at the entrance of the chute to indicate when the chute is full for the control of an automatic article feeding device. The chute may be used to transport articles between different levels, or to vertically store articles in a space saving manner for a multiple article picker system.
Description
BACKGROU~D OF THE INVENTION
In automatic picker systems, horizontal floor space is at a premium, so that it is desirable to store articles in a vertical direction, but as the angle of storage is increased, the problems associated with stacking articles in the storage area correspond-ingly increase particul~rly due to problems o~ velocity control and impact control.
There is ~ well known need to transport articles between different levels, and many types of conveyors, both powered and gravity operated, are known for this purpose.
In this article transport fieldJ powered transfer conveyors can control the velocity and impact o~ articles quite well, but usually in correlation to the expense involved in manufacture, maintenance and desi~n. Gravity conveyors have the extreme problem of runaway velocity that will damage articles or adjacent machinery when a moving article hits a stationary article.
Various types o~ retarders or slow moving conveyors solve the velocity and impact problems, but in turn they produce the problems o~ low volume flo~, that is they will have an undesirably low transfer capacity per unit of time.
SUMMARX OF THE IN~VENTION
It is an object of the present invlention to provide a transport device of the type discussed, without the disadvantages of the prior art. Particularly, a transport device is provided to move and store articles vertically with a low initial cost, low maintenance cost, and simplicity of operation as compared with the prior art, while at the same time providing for a high volume ~low rate, low impact shock for articles, automatic control, reliable speed control throu~hout movement that varies according to the number of articles already stored in the device.
In automatic picker systems, horizontal floor space is at a premium, so that it is desirable to store articles in a vertical direction, but as the angle of storage is increased, the problems associated with stacking articles in the storage area correspond-ingly increase particul~rly due to problems o~ velocity control and impact control.
There is ~ well known need to transport articles between different levels, and many types of conveyors, both powered and gravity operated, are known for this purpose.
In this article transport fieldJ powered transfer conveyors can control the velocity and impact o~ articles quite well, but usually in correlation to the expense involved in manufacture, maintenance and desi~n. Gravity conveyors have the extreme problem of runaway velocity that will damage articles or adjacent machinery when a moving article hits a stationary article.
Various types o~ retarders or slow moving conveyors solve the velocity and impact problems, but in turn they produce the problems o~ low volume flo~, that is they will have an undesirably low transfer capacity per unit of time.
SUMMARX OF THE IN~VENTION
It is an object of the present invlention to provide a transport device of the type discussed, without the disadvantages of the prior art. Particularly, a transport device is provided to move and store articles vertically with a low initial cost, low maintenance cost, and simplicity of operation as compared with the prior art, while at the same time providing for a high volume ~low rate, low impact shock for articles, automatic control, reliable speed control throu~hout movement that varies according to the number of articles already stored in the device.
- 2 ~
BRIEF DESCRIPTION OF THE DRAWING
Further objects, features and advantages of the present invention will become more clear from the following detailed descrip~ion of a preferred embodiment as shown in ~he accompanying drawing, where m:
~ IGURE 1 is a partially schematic, partially cross sectional, side elevation view o~ apparatus ~mbodying the present invention;
FIGURE 2 is a cross sectional view taken along line II-II;
FIGURE 3 is a plot of acceleration versus distance ~rom the point of free fall to the point of i.mpact with the downstream stationary article; and FIGURE 4 is a plot of velocity versus the distance corresponding to Figure 3.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
_ In Figure 1, there is shown a gravi~y transport device for moving a plurality of substantially identical articles la-le from a first upper station 2 to a second lower station 3. A suitable conveyor, such as endless conveyor 4 7 will feed articles, such as article le, at the first station 2. The conveyor 4 comprises a drive sprocket 5, a belt 6, an idler sprocket 7, and a motor 9, for driving the conveyor belt 6 in the direction of the arrow to move the article le into the inclined feed 8 of a chute 10. The inclined loading surace of the inclined eed 8 is sloped with respect ~o the horizon~al at an an~le ~, which is pre~erably 15 degrees, and the upper wall is slightly flared outwardly toward the article le with respect to the lower wall, so as to guide the ar~icle leinto the entrance end ll of the chutelO. As seen in Fi~ure 2, the chute 10 has a cross sectional shape that is complementary tn the corresponding cross sectional shape of the article le, so that there is a small uniform clearance between the article and the chute. The`chute 10 has such a uniform cross section throughout its entire extent from its en~rance end 11, to its exit end 12. Thus, the chute defines a central axis of symmetry, which would be perpendicular to Figure 2 and which in Figure 1 is vertical. While vertical is preferable, any vertical extent may be used so long as there is sufficient slope with respect to the horizontal to provide for gravity feed of articles travelin~ through the chute.
It is desirable ~o have the chute near true vertical, '~0 because it will take up less valuable horizontal space ~han if it were inclined more to the horizontal and provide for faster feeding of articles into the chute. The side walls of the chute are continuous and air impervious, so that when combined with the complementary telescoping shape of the chute and articles 1, the article ld traveling in the chute will function as a piston pump-ing air in front of it to increase the pressure of air in front of the falling article ld to a pressure that is greater than the air behind the article ld. In this sense, the walls are air impervious, although it is understood that assembly techniques and manufacturing tolerances can produce air leakage that is tolerable and vents may be deliberately provided along the length of the chute for speed control, while stlll considering such walls air impervious in the sense that the above-mentioned pump-ing action will occur and the speed control to be discussed below will result.
At the entrance end 11, a light source 13 powered by a battery 14, or the like, will pass a beam across the chute to a photocell 15 for producing a signal that is sent to the control 16.
When the light beam from source 13 is broken by an article, the signal will be interrupted to the controller 16, and if the signal is interrupted ~or longer than a fixed period of time that would indicate the interrupting article is stationary, the controller 16 will produce a control signal in the line 17 to stop th~ feed motor 9, to correspondingly stop the feeding of further articles into the entrance end of the chute, because the chute would be fully loaded or at capacity.
Spaced at a greater vertical distGance than the corresponding vertical height of the article la from the exit end 12 of the chute, there is a support surface 18, on which rests the lower-most or first article la. Thus, it is seen that the top surface19 of the article la is spaced slightly, for exa~ple 1/8 o~ an inch, below the bottommost surface of the chute lQ. An article lb rests upon the top of article la, ~nd extends sufficiently far into the exit end of the chute 10 that it will effectively pneumatically séal off the exit end of the chute. A light source 20, powered by a battery or other electrical source 21 produces a beam of light that will travel across the chute 10 to be intercepted by the photocell 22, to produce a signal in line 23 that ~ill be received by the control device 24. When an article intercepts this beam of ligh~ for more than a fixed period of ~, time to indicate that the article is stationary, the controller 24 will produce an output signal in line 25 to operate solenoid 26 for ohanging three-way valve 27 to its illustrated position wherein fluid, particularly hydraulic fluid fr~m the sump 28 m~y be moved by p~p 29 through the valve 27 to line 30, through open valve 31 to the expansible ch~mber device 32 that will reciprocate ram 33 laterally of the chute axis to slide the article la from beneath the article lb and onto an endless conveyor 33, driven by motor 34, so that the conveyor 33 may move the article to a desired location in a.dir~ction perpendicu-lar to the plane of Figure l. Thereafter, a suitable controlsignal is provided in line 35, for example under the actuation of a limit switch associated with the ram 33, so as to operate solenoid 36 to close the ~alve 31, vent the expansible chamber device 32 and withdraw the ram 33 to its illustrated position under the power o~ a return spring (not shown) in ~he expansible chamber device 32; at this time, the articles lc and lb will move downwardly so that the article lb will res~ upon the support - surface 18. Assuming that the article ld is still ~alling, the photocell 22 will produce a signal in line 23 that will indicate the absence of an article adjacent it, ~nd the control 24 will produce a signal in line 25 ~o operate the solenoid 26 so as to move valve 27 from its illustrated position to an exhaust posi-tion for the line 30 so that regardless of the operation of valve 31, the expansible chamber device 32 cannot be actuated to remove the lowermost ar~icle; in this manner, there is an inter-lock provided to prevent the removal o~ an article in the position lb as the topmost stationary article, so that the pneumatic seal for the exit end 12 of the chute will always be maintained~ .
The apparatus of Figure 1 may be operated by itself merely as a transpor~ device with some inherent stora~e, or may be operated by itsel~ as a picker device that will vertically store articles to be removed as needed, or operated in conjunction with a plurality of such chutes lOa, lOb, and lOc to provide multiple storage facilities as is well known in storage pickers. Theside elevation view of each o~ the chutes lOa, lOb, lOc would include equipment such as all of that illustrated in Figure 1, and if desired the internal shape of the chutes lO, lOa, lOb, lOc, etc., may b~ different to store and transport correspondingly differently shaped articles, but in any event the shape is complementary to the article to be carried in the chute with small clearance so as to produce the p~npin~ effect.
Thæ detectors that are constituted by the light source-photocell combinations may be omitted if this control is not needed, although it is desirable to include the lowermost detector even if manual picking is employed, that is, even if the ram 33, power cylinder 32, mechanism were removed, and in such case the si~nal in line 23 would then produce an audible or visual signal to indicate to the manual picker that the lower-most article should not be removed, or such si~nal may be used to place a barrier against the manual removal of the lowermostarticle. Of course, articles may be manually fed into the entrance end 11, and if desired the inclined feed may be omitted, since it merely serves the function of insuring proper positioning of the article in the entrance end 11.
When an article is first inserted in the entrance end 11 of the chute 10, the pressure on the upper surface of the article ~ill substantially balance the pressure on the lower surface of the article so that the article will freely ~all, when released, with the normal acceleration of gravity that is 32.2 feet per second per second. In Figure'3 and ~i~ure 4, the distance is plotted starting from the'far left-hand position corresponding to the point where the'article is released in the entrance end 11, that is point D and is measured vertica]ly along the axis of the chute and plotted towards the'right in these ~igures to point C
which is the point where the'falling article comes to rest on the immediately adjacent lower stationary article. Thereore, this distance D-C will vary according to the'height of stationary articles stacked within the chute,' ~nd of course in accordance with the actual height of the chute, but the'profile curves for the acceleration and velocity will correspondingly vary, that is they will be similar regardless of thé to~al distance. As seen in Figures 3 and 49 when the article is first released at the entrance end 11, point D, the'acceleration will have a positive value of 32.2 feet per second per second and the velocity will be zero. From po-int 0 to point A, the article will have a substantially steady acceleration equal to the acceleration of gravity, that is 32.2 eet per second per second as its velocity increases. Thereafter, the pressure'will begin to build up in front of the falling ar~icle due to the pumpin~ effect of the , article acting as a piston within the chute acting as a cylinder so that pressure in front of th~ article will begin to increase with respect to th~ pressure behind the falling article and accordingly the acceleration will continuously decrease from point A to point B while the velocity continues to increase. At point B, the acceleration will be zero and the velocity will be at a maximum. ~oving past point ~, the pressure will continue to build up in front of the article so that the acceleration will be negative, that is, there will be deceleration and correspondingly the velocity will steadily decrease as the falling article moves from point B to point C. At poin~ C, the falling article will impact with the nex~ lower stationary article lc, at which time the acceleration will substantially instantaneously return to zero and the velocity will su~stantially instantaneously return to zero. From Figure 4, it is seen that at the moment of impact at point C, there will be a small terminal velocity E for the falling article, which will be its velocity at impact. By controlling the tolerances between the chute and the article, this terminal velocity can ~e made quite small and in fac~
smaller than the terminal velocity of the article lb moving from its illustrated stationary position to where it impacts with the support surface 18 after the ar~icle la is removed and the ram 33 is returned to its illustrated position, which of course would result in no damage to the article. In ~ny event, it is critical to control the mating configuration between the chute and the article, and the exit end of the chute remain sealed by an article, or other means,so that the pumpin~ ~ction will occur sufficiently to build up pressure in front of the falling article so that deceleration will occur for a period of time immediately before impact sufficient to produce an acceptable terminal velocity.
~rom the above, it is seen that as the hei~ht of the stationary articles increases, the points B and C will correspondingly move upwardly in the chute, so that the speed control is self regulatin~ to the extent tha~ it will operate substantially the same regardless of the hei~ht of free fall.
Furthermore, it is seen that the speed control will permit maximum acceleration of the article and the very rapid reaching of a high transport speed, and thereafter the controlled deceleration sufficient to provide the desired impact terminal velocity. In this manner, the input feed rate from conveyor 4 may be very high and the volume flow handling capability of the transport device can correspondingly be very high and limited to no more extent than discharging articles into a totally vertically aligned free fall without a chute. Even i~ several articles are falling within the chute at the same time, it is seen that as a lower one of the falling articles slows down, the immediately upstream falling artic~e will start to move closer to the downstream article and thereby build up pressure between the two to control the approach velocity of two ~alling objects in a manner similar to that shown in ~igures 3 and 4 with respect to producing a relative deceleration of approach between the two articles.
While a preferred embodiment of the present invention has been described in detail as the best mode and for the advantages of the specific details, further embodiments, modifications and variations are contemplated according to the broader aspects of the present invention, all as determined by the spirit and scope of the following claims.
BRIEF DESCRIPTION OF THE DRAWING
Further objects, features and advantages of the present invention will become more clear from the following detailed descrip~ion of a preferred embodiment as shown in ~he accompanying drawing, where m:
~ IGURE 1 is a partially schematic, partially cross sectional, side elevation view o~ apparatus ~mbodying the present invention;
FIGURE 2 is a cross sectional view taken along line II-II;
FIGURE 3 is a plot of acceleration versus distance ~rom the point of free fall to the point of i.mpact with the downstream stationary article; and FIGURE 4 is a plot of velocity versus the distance corresponding to Figure 3.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
_ In Figure 1, there is shown a gravi~y transport device for moving a plurality of substantially identical articles la-le from a first upper station 2 to a second lower station 3. A suitable conveyor, such as endless conveyor 4 7 will feed articles, such as article le, at the first station 2. The conveyor 4 comprises a drive sprocket 5, a belt 6, an idler sprocket 7, and a motor 9, for driving the conveyor belt 6 in the direction of the arrow to move the article le into the inclined feed 8 of a chute 10. The inclined loading surace of the inclined eed 8 is sloped with respect ~o the horizon~al at an an~le ~, which is pre~erably 15 degrees, and the upper wall is slightly flared outwardly toward the article le with respect to the lower wall, so as to guide the ar~icle leinto the entrance end ll of the chutelO. As seen in Fi~ure 2, the chute 10 has a cross sectional shape that is complementary tn the corresponding cross sectional shape of the article le, so that there is a small uniform clearance between the article and the chute. The`chute 10 has such a uniform cross section throughout its entire extent from its en~rance end 11, to its exit end 12. Thus, the chute defines a central axis of symmetry, which would be perpendicular to Figure 2 and which in Figure 1 is vertical. While vertical is preferable, any vertical extent may be used so long as there is sufficient slope with respect to the horizontal to provide for gravity feed of articles travelin~ through the chute.
It is desirable ~o have the chute near true vertical, '~0 because it will take up less valuable horizontal space ~han if it were inclined more to the horizontal and provide for faster feeding of articles into the chute. The side walls of the chute are continuous and air impervious, so that when combined with the complementary telescoping shape of the chute and articles 1, the article ld traveling in the chute will function as a piston pump-ing air in front of it to increase the pressure of air in front of the falling article ld to a pressure that is greater than the air behind the article ld. In this sense, the walls are air impervious, although it is understood that assembly techniques and manufacturing tolerances can produce air leakage that is tolerable and vents may be deliberately provided along the length of the chute for speed control, while stlll considering such walls air impervious in the sense that the above-mentioned pump-ing action will occur and the speed control to be discussed below will result.
At the entrance end 11, a light source 13 powered by a battery 14, or the like, will pass a beam across the chute to a photocell 15 for producing a signal that is sent to the control 16.
When the light beam from source 13 is broken by an article, the signal will be interrupted to the controller 16, and if the signal is interrupted ~or longer than a fixed period of time that would indicate the interrupting article is stationary, the controller 16 will produce a control signal in the line 17 to stop th~ feed motor 9, to correspondingly stop the feeding of further articles into the entrance end of the chute, because the chute would be fully loaded or at capacity.
Spaced at a greater vertical distGance than the corresponding vertical height of the article la from the exit end 12 of the chute, there is a support surface 18, on which rests the lower-most or first article la. Thus, it is seen that the top surface19 of the article la is spaced slightly, for exa~ple 1/8 o~ an inch, below the bottommost surface of the chute lQ. An article lb rests upon the top of article la, ~nd extends sufficiently far into the exit end of the chute 10 that it will effectively pneumatically séal off the exit end of the chute. A light source 20, powered by a battery or other electrical source 21 produces a beam of light that will travel across the chute 10 to be intercepted by the photocell 22, to produce a signal in line 23 that ~ill be received by the control device 24. When an article intercepts this beam of ligh~ for more than a fixed period of ~, time to indicate that the article is stationary, the controller 24 will produce an output signal in line 25 to operate solenoid 26 for ohanging three-way valve 27 to its illustrated position wherein fluid, particularly hydraulic fluid fr~m the sump 28 m~y be moved by p~p 29 through the valve 27 to line 30, through open valve 31 to the expansible ch~mber device 32 that will reciprocate ram 33 laterally of the chute axis to slide the article la from beneath the article lb and onto an endless conveyor 33, driven by motor 34, so that the conveyor 33 may move the article to a desired location in a.dir~ction perpendicu-lar to the plane of Figure l. Thereafter, a suitable controlsignal is provided in line 35, for example under the actuation of a limit switch associated with the ram 33, so as to operate solenoid 36 to close the ~alve 31, vent the expansible chamber device 32 and withdraw the ram 33 to its illustrated position under the power o~ a return spring (not shown) in ~he expansible chamber device 32; at this time, the articles lc and lb will move downwardly so that the article lb will res~ upon the support - surface 18. Assuming that the article ld is still ~alling, the photocell 22 will produce a signal in line 23 that will indicate the absence of an article adjacent it, ~nd the control 24 will produce a signal in line 25 ~o operate the solenoid 26 so as to move valve 27 from its illustrated position to an exhaust posi-tion for the line 30 so that regardless of the operation of valve 31, the expansible chamber device 32 cannot be actuated to remove the lowermost ar~icle; in this manner, there is an inter-lock provided to prevent the removal o~ an article in the position lb as the topmost stationary article, so that the pneumatic seal for the exit end 12 of the chute will always be maintained~ .
The apparatus of Figure 1 may be operated by itself merely as a transpor~ device with some inherent stora~e, or may be operated by itsel~ as a picker device that will vertically store articles to be removed as needed, or operated in conjunction with a plurality of such chutes lOa, lOb, and lOc to provide multiple storage facilities as is well known in storage pickers. Theside elevation view of each o~ the chutes lOa, lOb, lOc would include equipment such as all of that illustrated in Figure 1, and if desired the internal shape of the chutes lO, lOa, lOb, lOc, etc., may b~ different to store and transport correspondingly differently shaped articles, but in any event the shape is complementary to the article to be carried in the chute with small clearance so as to produce the p~npin~ effect.
Thæ detectors that are constituted by the light source-photocell combinations may be omitted if this control is not needed, although it is desirable to include the lowermost detector even if manual picking is employed, that is, even if the ram 33, power cylinder 32, mechanism were removed, and in such case the si~nal in line 23 would then produce an audible or visual signal to indicate to the manual picker that the lower-most article should not be removed, or such si~nal may be used to place a barrier against the manual removal of the lowermostarticle. Of course, articles may be manually fed into the entrance end 11, and if desired the inclined feed may be omitted, since it merely serves the function of insuring proper positioning of the article in the entrance end 11.
When an article is first inserted in the entrance end 11 of the chute 10, the pressure on the upper surface of the article ~ill substantially balance the pressure on the lower surface of the article so that the article will freely ~all, when released, with the normal acceleration of gravity that is 32.2 feet per second per second. In Figure'3 and ~i~ure 4, the distance is plotted starting from the'far left-hand position corresponding to the point where the'article is released in the entrance end 11, that is point D and is measured vertica]ly along the axis of the chute and plotted towards the'right in these ~igures to point C
which is the point where the'falling article comes to rest on the immediately adjacent lower stationary article. Thereore, this distance D-C will vary according to the'height of stationary articles stacked within the chute,' ~nd of course in accordance with the actual height of the chute, but the'profile curves for the acceleration and velocity will correspondingly vary, that is they will be similar regardless of thé to~al distance. As seen in Figures 3 and 49 when the article is first released at the entrance end 11, point D, the'acceleration will have a positive value of 32.2 feet per second per second and the velocity will be zero. From po-int 0 to point A, the article will have a substantially steady acceleration equal to the acceleration of gravity, that is 32.2 eet per second per second as its velocity increases. Thereafter, the pressure'will begin to build up in front of the falling ar~icle due to the pumpin~ effect of the , article acting as a piston within the chute acting as a cylinder so that pressure in front of th~ article will begin to increase with respect to th~ pressure behind the falling article and accordingly the acceleration will continuously decrease from point A to point B while the velocity continues to increase. At point B, the acceleration will be zero and the velocity will be at a maximum. ~oving past point ~, the pressure will continue to build up in front of the article so that the acceleration will be negative, that is, there will be deceleration and correspondingly the velocity will steadily decrease as the falling article moves from point B to point C. At poin~ C, the falling article will impact with the nex~ lower stationary article lc, at which time the acceleration will substantially instantaneously return to zero and the velocity will su~stantially instantaneously return to zero. From Figure 4, it is seen that at the moment of impact at point C, there will be a small terminal velocity E for the falling article, which will be its velocity at impact. By controlling the tolerances between the chute and the article, this terminal velocity can ~e made quite small and in fac~
smaller than the terminal velocity of the article lb moving from its illustrated stationary position to where it impacts with the support surface 18 after the ar~icle la is removed and the ram 33 is returned to its illustrated position, which of course would result in no damage to the article. In ~ny event, it is critical to control the mating configuration between the chute and the article, and the exit end of the chute remain sealed by an article, or other means,so that the pumpin~ ~ction will occur sufficiently to build up pressure in front of the falling article so that deceleration will occur for a period of time immediately before impact sufficient to produce an acceptable terminal velocity.
~rom the above, it is seen that as the hei~ht of the stationary articles increases, the points B and C will correspondingly move upwardly in the chute, so that the speed control is self regulatin~ to the extent tha~ it will operate substantially the same regardless of the hei~ht of free fall.
Furthermore, it is seen that the speed control will permit maximum acceleration of the article and the very rapid reaching of a high transport speed, and thereafter the controlled deceleration sufficient to provide the desired impact terminal velocity. In this manner, the input feed rate from conveyor 4 may be very high and the volume flow handling capability of the transport device can correspondingly be very high and limited to no more extent than discharging articles into a totally vertically aligned free fall without a chute. Even i~ several articles are falling within the chute at the same time, it is seen that as a lower one of the falling articles slows down, the immediately upstream falling artic~e will start to move closer to the downstream article and thereby build up pressure between the two to control the approach velocity of two ~alling objects in a manner similar to that shown in ~igures 3 and 4 with respect to producing a relative deceleration of approach between the two articles.
While a preferred embodiment of the present invention has been described in detail as the best mode and for the advantages of the specific details, further embodiments, modifications and variations are contemplated according to the broader aspects of the present invention, all as determined by the spirit and scope of the following claims.
Claims (2)
1. A method for transporting a plurality of sub-stantially identically shaped articles to move them from a first station to a second station that is vertically spaced below the first station, comprising the steps of:
providing an enclosed, stationarily mounted tube having a longitudinal axis extending vertically between the first station and the second station, with the tube being generally open at an entrance end adjacent the first station and open at an axially spaced exit end adjacent the second station;
maintaining the walls of said tube, between said exit end and said entrance end continuous and generally impervious to the flow of air through them to form, except for said entrance end and said exit and, an air tight passage;
providing said tube with a uniform cross sectional shape perpendicular to its axis throughout the entire extent of said tube between said entrance end and said exit end, which is substantially the same as the corresponding cross sectional shape of the articles to be transported;
stationarily supporting a first article on a support spaced in the direction of said axis from the exit end of said tube a distance greater than the height, in the axial direction, of the first article so as to support the first article at the second station in a position immediately adjacent and spaced from the exit end of said tube;
supporting a second article on the first article, with such second article being partially within the exit end of said tube for effectively closing and partially air sealing the exit end of said tube;
thereafter inserting a plurality of the articles in the entrance end of said tube in serial fashion with such articles having a common substantially identical cross sectional shape as seen in a plane perpendicular to the axis of the tube when they are oriented in said entrance end of said tube and releasing said articles to fall by gravity within said tube;
providing all the articles so that they have a small clearance fit with the sides of said tube suffi-cient to build up air pressure in front of them above atmos-pheric pressure as they travel by gravity in said tibe towards the exit end of said tube that is closed by the supported articles;
maintaining the air closure at the exit end of said tube by said supported articles, a clearance between the falling articles and the interior surfaces of said tube sufficiently small, and an air imperviousness of said tube throughout the axial length of said tube through which said articles fall all sufficient to build up air pressure in front of said falling article that will reduce the initial acceleration of gravity of said falling article to zero and thereafter produce an increasing deceleration for said article to correspondingly first increase the velocity of the falling article from said entrance end to a maximum at a point in said tube corresponding to zero acceleration and thereafter correspondingly decrease the velocity of the falling article in response to the decleration produced by the air pressure in front of the falling article through the travel of the falling article in said tube until impact with an immediately downstream stationary supported article blocking further travel in said tube;
detecting the presence of at least more than one article supported within said tube; and laterally, with respect to said axis, withdraw-ing the lowermost supported article that is spaced axially from the exit end of said tube from the supported articles only when at least two supported articles are in said tube.
providing an enclosed, stationarily mounted tube having a longitudinal axis extending vertically between the first station and the second station, with the tube being generally open at an entrance end adjacent the first station and open at an axially spaced exit end adjacent the second station;
maintaining the walls of said tube, between said exit end and said entrance end continuous and generally impervious to the flow of air through them to form, except for said entrance end and said exit and, an air tight passage;
providing said tube with a uniform cross sectional shape perpendicular to its axis throughout the entire extent of said tube between said entrance end and said exit end, which is substantially the same as the corresponding cross sectional shape of the articles to be transported;
stationarily supporting a first article on a support spaced in the direction of said axis from the exit end of said tube a distance greater than the height, in the axial direction, of the first article so as to support the first article at the second station in a position immediately adjacent and spaced from the exit end of said tube;
supporting a second article on the first article, with such second article being partially within the exit end of said tube for effectively closing and partially air sealing the exit end of said tube;
thereafter inserting a plurality of the articles in the entrance end of said tube in serial fashion with such articles having a common substantially identical cross sectional shape as seen in a plane perpendicular to the axis of the tube when they are oriented in said entrance end of said tube and releasing said articles to fall by gravity within said tube;
providing all the articles so that they have a small clearance fit with the sides of said tube suffi-cient to build up air pressure in front of them above atmos-pheric pressure as they travel by gravity in said tibe towards the exit end of said tube that is closed by the supported articles;
maintaining the air closure at the exit end of said tube by said supported articles, a clearance between the falling articles and the interior surfaces of said tube sufficiently small, and an air imperviousness of said tube throughout the axial length of said tube through which said articles fall all sufficient to build up air pressure in front of said falling article that will reduce the initial acceleration of gravity of said falling article to zero and thereafter produce an increasing deceleration for said article to correspondingly first increase the velocity of the falling article from said entrance end to a maximum at a point in said tube corresponding to zero acceleration and thereafter correspondingly decrease the velocity of the falling article in response to the decleration produced by the air pressure in front of the falling article through the travel of the falling article in said tube until impact with an immediately downstream stationary supported article blocking further travel in said tube;
detecting the presence of at least more than one article supported within said tube; and laterally, with respect to said axis, withdraw-ing the lowermost supported article that is spaced axially from the exit end of said tube from the supported articles only when at least two supported articles are in said tube.
2. The method of claim 1, wherein said step of detecting automatically produces a corresponding detection signal indicating the presence of more than one article supported within said tube; and said step of withdrawing will automatically block the withdrawal of the lowermost supported article in the absence of said signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US5912879A | 1979-07-20 | 1979-07-20 | |
| US59,128 | 1979-07-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1122133A true CA1122133A (en) | 1982-04-20 |
Family
ID=22021033
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000356324A Expired CA1122133A (en) | 1979-07-20 | 1980-07-16 | Air cushion chute |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1122133A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4679704A (en) * | 1984-10-31 | 1987-07-14 | Dunlop Raymond B | Gravity pipe transport system |
| AT13398U1 (en) * | 2010-04-19 | 2013-12-15 | Ssi Schaefer Peem Gmbh | VERTICAL BODY TRUCK AND STACKER |
| CN110329713A (en) * | 2019-06-15 | 2019-10-15 | 浙江安驰建设有限公司 | One kind being used for building construction project residue conveying device |
-
1980
- 1980-07-16 CA CA000356324A patent/CA1122133A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4679704A (en) * | 1984-10-31 | 1987-07-14 | Dunlop Raymond B | Gravity pipe transport system |
| AT13398U1 (en) * | 2010-04-19 | 2013-12-15 | Ssi Schaefer Peem Gmbh | VERTICAL BODY TRUCK AND STACKER |
| CN110329713A (en) * | 2019-06-15 | 2019-10-15 | 浙江安驰建设有限公司 | One kind being used for building construction project residue conveying device |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |