US3054234A - Sealing machine and method - Google Patents

Description

Sept. 18, 1962 H. E. sTOVER SEALING MACHINE AND METHOD Filed Feb. 5, 1960 8 Sheets-Sheet l IN V EN TOR. f/np y E 5 rolls? A my/YE) Sept. 18, 1962 H. E. STOVER SEALING MACHINE AND METHOD 8 Sheets-Sheet 2 Filed Feb. 5, 1960 .Ll ll AM k nu l L s JIIU n INVENTOR.

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SEALING MACHINE AND METHOD Filed Feb. 5, 1960 8 Sheets-Sheet 8 SI I i 8 Q 9 n E ,lllllllll-lllllllllllllllllll [F \RZ'w S 949) E. Srovee ZWQMMQ AFTO P/YFY United States Patent 3,054,234 SEALING MACHINE AND METHOD Harry E. Stover, Lancaster, Ohio, assignor to Anchor Hocking Glass Corporation, Lancaster, Ohio, a corporation of Delaware Filed Feb. 5, 1960, Ser. No. 6,993 18 Claims. (Cl. 53-38) The present invention relates to the sealing art and more particularly to a machine and method for sealing screw caps, preferably the lug type, to containers.

Lug caps or closures are special types of screw caps in which lugs on the closure engage corresponding threads or lugs on the container finish to pull the closure down at a plurality of points throughout the circumference. This type of cap dilfers from the continuous thread cap where a helical thread extends completely about the finish to mate with a corresponding helical thread extended entirely about the closure. Lug caps may be screwed on in a fraction of a turn, usually a quarter turn for large size caps or a one-half turn for small sizes; whereas, continuous thread caps require a complete turn.

Two general types of machines have been utilized for applying screw closures to containers. The first type utilizes a turret and a series of chucks for screwing the caps on. The second type utilizes a pair of belts or discs engaging opposite sides or top portions to screw the closures into sealed position on containers which are moving forward on a straight conveyor. The belts or discs have to be driven at different speeds or in different directions to screw the caps on.

The present invention relates to the second type of machine and avoids the use of a pair of belts or discs and the necessity for a pair of drives for driving them at different speeds, or in opposite directions to screw the caps on. The present invention provides a stationary shoe resiliently held in position to engage right elf-center portions (viewed from the entrance end of the machine) of the closures to quickly screw the closures on as they move past the shoe while seated on containers carried by a conveyor belt. A single belt with a single drive may engage the left olfcenter portion of the closure to facilitate the operation. Thus, the sealing operation is simplified, wear is minimized, and a secure seal is obtained.

The invention also improves the seating and initial threading of the closure on the finish by magnetically suspending the closures, freely movable laterally in any direction at the time the closures are telescoped onto the glass finish so that each closure may accurately center itself on the threaded finish.

An object of the present invention is to provide an improved machine and method for applying screw closures, preferably of the lug type.

Another object of the invention is to provide a sealing machine and method for applying screw closures which is simple in design, readily adjustable and effective in providing a secure seal.

Another object of the invention is to provide a sealing machine in which wear, particularly wear on replaceable elements, is reduced to a minimum.

Another object of the invention is to provide an improved mechanism for seating and initially threading closures on containers.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification wherein:

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FIG. 1 is a side elevational view of a sealing machine in accordance with the present invention;

FIG. 2 is a top plan view of the sealing machine of FIG. 1;

FIG. 3 is a perspective view of the closure applying means and the sealing means of the sealing machine of FIG. 1;

FIG. 4 is a sectional view of the sealing machine taken along lines 44 of FIG. 8;

FIG. 5 is an enlarged detailed view of the sealing means of the sealing machine of FIG. 1; I

FIG. 6 is a horizontal sectional view of the sealing means taken along lines 66 of FIG. 5;

FIG. 7 is a vertical sectional view of the sealing means taken along lines 77 of FIG. 5; 1

FIG. 8 is a plan view partially cut away of the sealing head of the sealing machine of FIG. 1 showing the side belts and the conveyor belt;

FIG. 9 is a side elevational view partially cut away of the sealing head showing the sealing means; 7

FIG. 10 is an enlarged detailed view of the steam connections for the machine;

FIG. 11 is a sectional view taken along lines 1111 of FIG. 10;

FIG. 12 is a sectional view of the steam tunnel taken along lines 12-12 of FIG. 10;

FIG. 13 is an enlarged detailed side elevational view of the cap applicator of the present invention;

FIG. 14 is a top plan view of the cap applicator of FIG. 13;

FIG. 15 is a sectional view of the cap applicator taken along lines 15-15 of FIG. 13;

FIG. 16 is an enlarged detailed side elevational view of the sealing belt and its mounting;

FIG. 17 is a fragmentary view of another embodiment of the cap applicator; and

FIG. 18 is a sectional view of the magnetic wheel taken along lines 1818 of FIG. 13.

General Description The sealing machine will first-be described generally with particular reference to FIGS. .1 through 4. As illustrated in FIG. 1 the sealing machine 1 includes an endless conveyor belt 2 mounted on a suitable base 3 0m end sprockets 4 and 5. This mounting provides for a. horizontal upper run 6 of the conveyor belt 2 over the top of base 3 so that the filled containers fed onto the conveyor belt 2 adjacent sprocket 4 are carried in succession beneath the closure applying and sealing head indicated generally at 7. As illustrated in FIG. 2 a suitable drive motor 8 is provided in the base 3 which standard coupling means interconnecting the motor 8 and one or both of the sprockets 4 and 5.

The improved closure applying andsealing head 7 is illustrated in FIG. 3. As the filled containers 12 are moved by the conveyor 2 between suitable adjustable guide rails 9, the containers 12 first pass through a steam tunnel 10 which directs steam into the container head spaces to displace the air and to provide a partial vacuum when the container is thereafter sealed. As the containers 12 leave the steam tunnel 10 they pass beneath a closure applicator indicated generally at '11. As will be more fully described below, each of the containers 12 draws a closure 14 from the applicator 11 so that the closure 14 is telescoped loosely about the container mouth and is held in a level position above the container mouth. Next the applicator presses the closure 14 lightly and levelly downward while the closure is simultaneously given an initial slight rotation to cause an initial engagement between the threads of the closure 14 and the container 12. Thereafter the containers 12 pass on conveyor 2 beneath the sealing means indicated generally at i where the closure 14 is simultaneously rotated and forced downwardly into tight sealing engagement with the container finish. -The improved sealing means 15, which will be described in detail below, preferably comprises an endless driven belt 16 and a fixed shoe 17. As illustrated in FIG. 4, the moving belt 16 contacts an outer portion of the top of the closure 14 and the fixed shoe 17 contacts an opposite portion of the closure top. The belt 16 may be driven at a speed greater than that of the conveyor. The fixed shoe 17 provides a drag friction force on the closure top. Thus, the combined effect of the opposite forces of the belt 16 and the shoe 17 is a rotation drive which turns the closure 14 downwardly onto the container threads while the gasket in the closure 14 is pressed tightly against the container finish.

An elongated steam distributor 18, FIGS. 3 and 10, is positioned adjacent the sealing means 15 and parallel to the conveyor belt 2 to emit a sheet or cloud of steam from its elongated side port 19 to provide a steam atmosphere surrounding the closures 14 and the tops of the containers 12 during the sealing operation. This prevents the re-entrance of air into the containers before and during the sealing operation to insure the completion of the seal without the re-entry of air into the con-. tainer. After the sealed containers 12 move beyond the sealing means 15, the cooling of the head space causes the steam to condense and a partial vacuum to form within the head space.

As illustrated in FIG. 3, side belts 20 and 21 respectively are provided to engage the opposite sides of the containers 12 as they pass through the sealing head 7 on conveyor 2 to support the containers at the applicator station and to prevent rotation of the containers as the closures 14 are rotated into their sealed position. Each of the belts 20 and 21 is mounted on a drive pulley 22 and on idler pulleys 23. Pulleys 22 are driven by motor 8 to move the side belts 20 and 21 at the same speed as the conveyor 2. Positioning pulleys 24 which are adjustably positioned laterally of conveyor 2 are provided to hold the side belts 20 and 21 inwardly against the moving containers 12 to position the containers 12 centrally beneath the closure applicator 11 and the sealing means 15 as illustrated in FIG. 4 and to move the containers forward at the speed of the conveyor 2.

The Closure Applicator The closure applicator 11 is illustrated in detail in FIGS. 13-45. As best seen in FIG. 13 the applicator comprises an inclined cap chute having a channel 31 to slideably receive a line of closures 14 as they are fed into the top of the chute 30 by a suitable cap feed (not shown). The closures 14 slide downwardly in channel 31 under the force of gravity until they reach the position of closure 14 at the lower end 32. As illustrated in FIGS. 13 and 14, the closure 14 is held in this lowermost position adjacent the lower end 32 by the inwardly spring biased pin members or detents 34.

At this point the closure 14 at the bottom 32 of the chute 30, with its lower side depending beyond it, is about to be engaged and removed from the chute by the container 12 engaging the overhanging skirt to pull it from the chute 30 past or over the biased pins or detents 34. Since the closure 14' is to be screwed onto the con tainer, the lugs of the closure 14 have to engage under the lugs or thread portions on the glass finish, 35. If a lug on one side of the closure 14 engages under a thread on the glass finish and the lug on the opposite side of the closure 14' is on top of the thread on the finish a so-called cocked cap results. A cocked cap cannot be screwed on properly. Usually, the downward pressure spreads the skirt of the cap to make the lug jump the thread and an imperfect seal results.

In order to prevent cocked caps and to initially thread the closure 14' onto the glass finish of container 12' so that the lugs on the closure 14' all engage under the respective threads on the container, the preferred embodiment of cap feed or applicator provides three elements adapted to cooperate in leveling the cap 14 on the finish 35 and in initially threading it on the container finish.

First (FIG. 13), a magnetic wheel 38 having magnets 38' engages the cover part of the closure 14' and suspends it with the front end in engagement with the front part of the finish. The wheel 38 holds the cap 14 in an upper position to prevent al ug from prematurely engaging under a container thread and assists in the transfer of the closure 14' from the lower end of the chute 30 to the second element, that is, the leveling element 40 which also has a series of magnets 41 to hold the cap in raised position with the lower part telescoped over the container finish (FIG. 18). The third leveling element or plate 42 utilizes a pair of rails for initially threading the level cap 14" on the glass finish.

Where the closure 14' is kept in a horizontal or level position while it is pressed down on the glass finish there is no occasion for the closure to cock. It is held in level position to prevent one lug from getting under one thread and the opposite lug above the opposite thread on the glass finish.

These three elements for placing the closure on and initially threading it to the container, will now be described in detail.

Referring further to FIGS. 13 and 14 the magnetic wheel 38 comprises a pair of steel discs 37 spaced apart by a center disc of nonmagnetic material. The center disc may be Micarta, or a similar plastic material. A series of magnets 38 mounted in the center disc at its periphery have their poles in contact with the two discs 37, making them the north and south poles of a circular magnet and hence the edges of the discs 37 will magnetically support or suspend the closure 14 as it passes from the lower end of the cap chute 30 to the first leveler 40. The cap 14 is pulled forward by being initially telescoped over the moving container 12'. Preferably, the wheel 38 is as light as possible to minimize the effect of inertia. The wheel 38 may be mounted at the bottom of the chute 30 directly above the moving containers 12' and closures 14', by the arms 48 having bearings for the shaft 37' passing through the center of the wheel 38. The arms 48' are secured to the leveling plate 40.

The first leveling plate 40 which receives the closures 14' as they pass from the wheel 38 is pivotally mounted at shaft 47 on the end of cap chute 30 and has an extension 48. The extension 48 is used to adjust the position of the plate 40 by means of the adjustable limit screw 43 which fits into slot 43 in its adjusted position and to permit an upward tilting of the leveling plate 40 for off-size closures or containers or for tilted containers. The leveling plate 40 is preferably given a slight downward slope to cause the closure to be lowered onto the container finish as the container is moved toward the end of the leveling plate 40.

The third element 42 for initially threading the level closure 14" on the finish is pivotally mounted on the cap chute 30 at 52 at the ends of the pair of arms 50 which are secured by pivotal connection 51 on the front end of the leveler 42. Thus, initial threading plate 42 is pivoted at 51 to swing upwardly about a relatively short radius and is also pivoted at 52 to move up as an entirety about a rather long radius. The lower portion of the threading plate 42 has spaced rails 44 and 45 to engage the closure cap. The rail 44 has a smooth relatively frictionless surface while the rail 45 preferably has its lower surface 45' formed of rubber or other friction material which serves to retard one side of the closure to rotate it and to initially thread the closure on the finish while the rails 44 and 45 hold the closure level. The friction element rail 45 turns the cap 14" to initially thread it onto the container 12" but the force exerted is not great enough to do more than to start the threading operation. Since the cap 14" is kept horizontal on the finish when it reaches the threading member 42 and during its passage under the rails 44 and 45 thereof, there is no tendency for the closures to coc and hence cocked caps are avoided.

An adjusting screw 54 on the plate 42 adjust-ably engages the upper side of the leveling plate 40 to control the angular position of the friction element rail 45.

The closure applicator 11 is detachably mounted on the steam tunnel housing by removal pins 57 and brackets 58 (FIG. 13).

Another embodiment of the cap applicator is illustrated in FIG. 17. In this cap applicator the coaxing plate 42 is pivotally mounted on the end of the leveling plate at? by means of the link 50' which is pivotally attached to the coaxing plate 42 and the leveling plate 40' at pivots 51' and 52 respectively. The coaxing plate 42' has parallel closure cap engaging rails similar to those of the coaxing plate 42 with a friction member 45" attached to the lower surface of one rail to provide a drag force to cause the initial light rotation of the closure 14 into engagement with the threads of the containers 12 as the closure moves beneath the coaxing plate 42.

The Container Sealing Means As described above, each of the containers 12 is moved away from the closure applicator 11 with a closure 14 applied to the top of the container and with the closure threads or lugs lightly turned into an initial engagement with the container threads or lugs. The conveyor 2 now carries the containers 12 beneath the container sealing means which is illustrated in detail in FIGS. 3 through 8.

The container sealing means 15 comprises a moving endless belt 16 which engages one off-center portion of the closure and a stationary shoe member 17 which simultaneously engages the opposite off-center portion of the closure. The endless belt 16 is mounted on a drive pulley 61, idler pulley 62, and a tensioning pulley 64.

The lower run 65 of the endless sealing belt 16 is guided and positioned by a pressure guide 66 (FIGS. 7 and 16) which is mounted on two brackets 67 and 68 connected to the top of the enclosure 95 illustrated in FIG. 16. The brackets 67 and 68 are connected to bracket connectors 69 which are adjustably positioned vertically of the enclosure 95 by means of the threaded connection 70. The upper portion 71 of the brackets 67 and 68 is slideably fitted within the connectors 69 and held in a normally downward position therein by compression springs 72. The compression or downward force of the spring 72 is set by the pressure control knobs .73 which are threadedly connected at the top of the bracket connectors 69.

The fixed shoe 17 is mounted parallel to and on the same general level as the lower run 65 of the belt 16 by being attached to the belt pressure guide 66 by connector plates 87. Thus the vertical position of both the lower run 65 of belt 16 and of the fixed shoe 17 is adjusted by the bracket connectors 69 and the pressure exerted downwardly on the closure during the closure tightening action of the cooperating moving belt 16 and fixed shoe 17 is set by the adjusting pressure control knobs 73. When the containers 12 and their respective closures 14 move beneath the belt 16 and the fixed shoe 17, downward pressure is applied to the closure 14 by the controlled upward motion of the belt 16 and the shoe 17 and the resulting compression of the spring 72 in an amount controlled by the presure control handle 73. The simultaneous forward movement of the lower run of belt 16 and the frictional drag force of the fixed shoe 17 rotate thrust member for the sealing means 15 to position it longitudinally of the conveyor belt 2. A tensioning arm 81 mounted on pinion 80 holds the tensioning pulley 64 in engagement with the sealing belt 16. The tensioning arm 81 includes telescoping members 82 and 84 and a compression spring 85. The amount of spring force exerted by spring 85 is adjusted by the threaded coupling 86.

The fixed shoe 17 which is positioned outwardly of the belt 16 in position to engage the closure top is attached to the belt pressure guide 66 by connector plates 87. In order to provide for a height adjustment of the fixed shoe 17 independently of the belt pressure guide 66, adjusting screws 88 are provided on each of the mounting plates 87 to lock the relative positions of the plates 87 and the fixed shoe 17 on connector screw 89 as illustrated in FIG. 7.

In order to provide for a frictional engagement between the fixed shoe 17 and the closure 14 a friction lining 90 is riveted or otherwise attached to the bottom surface of the fixed shoe 17.

As seen in FIG. 5 the lower surface of the fixed shoe 17 preferably has a relatively horizontal and flat short downwardly projecting center portion 91 which provides the final degree of downward sealing pressure and assures quick rotation of the closure into its final sealed position on the container threads while it is subjected to the downward sealing force. The portions of the shoe 17 leading up to the sealing surface 91 comprise a curved end 92 to provide a lead-in section for the moving closures 14 and a relatively level initial contact portion 93 between portions 91 and 92 which bridges the friction member 90 so that it is permitted to flex upwardly to accommodate it to the closure 14 and to initiate the closure rotation as the closures 14 move into the final sealing portion 91.

The belt positioning shoe preferably has similar lead-in and lead-out portions and a fiat center sealing portion 94 which applies the final torque and sealing pressure.

In order to prevent rotation of the containers 12 while the closures are being screwed into their final sealed position, the side belts 20 and 21 are provided. These are mounted on drive pulleys 22 and idler pulleys 23 and their container contacting portions are held inwardly against the containers by positioning pulleys 24. The pulleys 24 are adjustably mounted on the sides of the enclosure 95 as illustrated in FIGS. 4 and 8. In the preferred embodiment, a plurality of pulleys 24 are mounted on suitable brackets 97 on opposite sides of the conveyor belt 2. A unitary positioning control is provided for the pulleys 24 so that the single control handle 96 may be rotated to move the belts to their correct position above the conveyor for a proper gripping of the containers 12. The brackets 97 for the pulleys are each mounted on the housing 95. Each of these arms has a rack and pinion connection 100, 101 (FIG. 4) to shafts 102 which are interconnected to each other and to control handle 96 by intercoupled shafts 104, 105, and 106 (FIGS. 4 and 9). Rotation of handle 96 thus provides for a simultaneous inward or outward movement of the belts 29 and 21 laterally of conveyor 2 and the adjustments may be made while the sealing machine 15 is in operation.

While the machine including the closure feed is primarily designed for the application of screw closures the cap feed particularly is applicable for feeding and initially applying any type of closure. Where the initial turning or coax-ing is not desired the rubber or friction rail may be changed to a smooth metal rail corresponding to rail 44.

Where press-on caps are thus used the final seal is made by a downward pressure which may be provided by using a wider sealing belt in place of belt 60 so that the belt covers the lower surface of both of the shoes 66 and 17. A wider drive pulley to accommodate the broader belt may be substituted for 61.

Operation The operation of the improved sealing machine which has been described in connection with the detailed description of the machine and method will now be summarized.

As indicated above the sealing machine 1 may be used for a wide variety of container and closure sizes. Once the container diameter has been determined the side rails 9 and the container gripping belts 20 and 21 are adjusted for the container diameter. The guide rails 9 are positioned centrally of the conveyor and the closure applicator means 11 and the sealing means 15. The container gripping belts 20 and 21 are adjusted laterally of the conveyor 2 to provide a continuous movement of the container on conveyor 2 past the closure applying means 11 and to prevent rotation of the containers 12 as the closures 14 are applied by the sealing means 15. As described above, the single adjusting knob 96 is rotated to move the positioning pulleys 24 laterally of the conveyor belt 2 to provide the necessary spacing of the belts 29 and 21.

When the container height has been determined an initial vertical adjustment is made of the closure app-lying and sealing means 7 which is vertically movable as a unit on the base 3 by adjustable posts 99 (FIG. 4). This adjustment on the post members 99 (FIG. 4) provides for the initial vertical positioning of both the closure applicator 11 and the sealing means 15.

The sealing means 15 is adjusted independently of the closure applicator 11 by rotating the threaded bracket connectors 69 at the top of the enclosure 95. This adjustment is made to position the lower run 65 of the sealing belt at the proper height so that it exerts the desired horizontal cap rotating force simultaneously with the downward sealing force. Adjustment of the vertical position of the lower run of the belt 16 also places the fixed shoe 17 at about its proper height. Additional fine adjustments of the height of the shoe 17 are made initially or during the preliminary test runs by the adjusting screws 88 and 89 (FIG. 7) which provide a fine height adjustment for the fixed shoe 17 and also adjust both the longitudinal and lateral slope of the friction surface 90 of the fixed shoe 17 to provide for the correct frictional force with the closure caps 14 as the containers 12.draw the closures 14 beneath the cooperating belt 16 and the shoe 17.

The initial threading of the closure 14 beneath the coaxing plate 42 is controlled by the vertical position of the plate 42 and this is set by raising or lowering the adjusting screw 54 (FIG. 13) to increase or decrease the amount of the initial coaxing rotation applied to the closure by the plate 42.

In the regular sealing operation of the machine the containers 12 are fed in spaced relationship onto the moving conveyor 2 adjacent end pulley 4. If desired, a suitable additional spacing means may be provided adjacent conveyor 2 such as a container spacing helicoid. Containers moving on the conveyor 2 are first carried beneath the steam tunnel 10 as illustrated in FIG. 12 and steam issuing downwardly from the tunnel enters the container head space and displaces the air therefrom. Further movement of the containers carries them to the end 104 (FIG. 10) of the steam tunnel 10 at which point the nozzle 105 directs an additional jet of steam into the head space and also against the under side of the lowermost closure 14' in the cap chute 30. This insures the removal of trapped air from the container head space and from beneath the closure 14 just prior to the application of the closure 14 to the container 12. The closure 14' is loosely applied to the container 12 as illustrated in FIG. 13 by movement of the upper edge 35 of the container 12' against the skirt of the lower-most closure 14' in the cap chute 30 whereby the closure 14' is drawn over the container finish and past the detents 34 on the lower end of the cap chute. As the cap is drawn past detents 34 and onto the top of the container 12' the magnetic wheel 38 rotates with the closure 14' so that the closure 14 is held up against the lowermost surface of the leveling plate 40 and is thus moved to level position on the container finish while telescoped about the finish and moving forward with the containers.

As the closure 14 is drawn beyond the magnetic wheel 38 additional magnets 41 in the leveling plate 40 continue to hold the closure 14" in a level raised position about the top of the container 12". Additional movement of the container 12" brings the closure 14" into contact with the coaxing plate 42 as illustrated in FIG. 15. The top of the closure 14" is engaged at spaced positions by the smooth metal rail 44 and the rubber friction member 45. This provides a light rotation force which rotates the closure 14" at least a fraction of the revolution and provides for an initial light engagement between the threads of the closure and the container. Continued movement of the conveyor belt 2 now carries the containers 12" with its loosely applied closure 14" beneath the sealing means 15.

The container 12 is located centrally of the sealing means 15 as illustrated in FIG. 7 so that the closure top is simultaneously engaged by the moving belt 16 and the friction member on the lower surface of the fixed shoe 17. The initial portions of both the belt and the friction members are inclined downwardly to provide for a gentle engaging contact between the closure 14 and the belt 16 and friction member 17. As described more fully above the moving belt 16 in cooperation with the frictional braking action of the fixed shoe 17 causes the closure 14 to be screwed downwardly to seal the container. Simultaneously, both the belt 16 and the shoe 17 provide a downward sealing force which facilitates the sealing action. This downward pressure is provided by springs 72 (FIG. 16) as described above so that when the container reaches the portion of the belt and the friction member in engagement with the flat centers 91 and 94 respectively of the shoes 66 and 17 the combined rotational and downward force are sufficient to screw the closure 14 into sealed position with the proper amount of torque.

As illustrated in FIG. 10 an elongated steam tunnel 18 is provided adjacent both the closure applying means 11 and the container sealing means 15 so that a sheet of steam envelopes the tops of the containers and the closures to prevent the reentry of air into the containers during the sealing operation and to insure the creation of the desired vacuum in the head spaces of the sealed con tainers.

It will be seen that the present invention provides an improved mechanism for initially threading screw closures, preferably of the lug type, to glass finishes which avoids cocked caps or crossed threads. The closures during initial application are suspended magnetically in partially telescoped relation to the glass finish as they move with the container. By suspending the closures magnetically they are free to move horizontally in any direction and to center themselves on the finish. By maintaining the closures in a horizontal position cocked caps are avoided. The initially threaded closures pass under a braking shoe which applies an effective braking action to screw the closure into final sealing position. A moving belt engaging the opposite off-center portions of the closures prevent them from cocking and facilitates the application of sufficient torque to provide a secure seal. Both the initial threading mechanism and the final sealing means are simple in construction and effective in operation.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and Without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention I claim:

1. In a machine for sealing containers with screw caps the combination of an endless belt positioned with its lower run engaging an off-center portion of closure cap tops seated upon moving containers, drive means for said belt adapted to move the lower run at a given speed in the direction of the moving containers, a shoe mounted adjacent said belt and restrained against movement in the direction of said moving containers and positioned to engage opposite off-center portions of said closure cap tops and pressure means resiliently urging said lower run of said belt and said shoe downwardly against the closure caps whereby said belt and said shoe cooperate to press said closure caps downwardly and to screw them into sealing engagement with containers.

2. A machine for sealing containers with screw caps comprising the combination of a conveyor to move containers along a generally horizontal path, a pair of sealing members mounted above said conveyor to engage opposite off-center portions of closure cap tops seated on moving containers on said conveyor, one of said sealing members comprising a contact shoe and being restrained against movement in the direction of conveyor movement and the other comprising an endless belt, drive means coupled to said belt and adapted to move it faster than said conveyor, and pressure means for urging said belt and shoe downwardly against the closure caps seated on containers passing beneath them whereby said shoe and said belt cooperate to screw the closures downwardly onto the containers.

3. In a machine for sealing containers with screw caps, the combination of a conveyor to move containers along a generally horizontal path, a closure chute adapted to feed a closure cap to each container on said conveyor, a pair of spaced elongated rails positioned generally parallel to said path to contact opposite off-center portions of the tops of closures on said containers, one of said rails having a greater friction coeflicient than the other to initially rotate the closures contacted by said rails, an endless belt mounted to engage one of two opposite elf-center portions of closure cap tops seated on containers on said conveyor, a shoe mounted adjacent said belt to engage the opposite off-center portions of said closure cap tops, and pressure means urging said shoe and said belt downwardly against the closure cap top whereby said shoe and said endless belt cooperate to screw the closures downwardly onto the containers.

4. The machine as claimed in claim 3 in which the lower surface of said shoe slopes downwardly from its front and rear ends to a central generally horizontal sealing portion.

5. A sealing machine for sealing containers with threaded-type caps comprising a conveyor adapted to carry a succession of containers in a generally horizontal path, a cap applicator positioned above said conveyor adapted to apply closures to the tops of containers being moved therebelow by said conveyor, and a container sealing means for thereafter screwing the caps onto said containers comprising an endless belt positioned above said conveyor and having a lower run aligned to move in the direction of said conveyor, drive means coupled to said belt adapted to drive it at a given speed, a friction member mounted adjacent to said endless belt and above said conveyor and generally parallel to the lower run of said endless belt and restrained against movement in the direction of the conveyor belt path, said endless belt and said friction member positioned to engage opposite elf-center portions of the closure cap top-s.

6. A sealing machine for applying screw caps to containers comprising, in combination, a conveyor adapted to carry a succession of containers in a generally horizontal path, a chute positioned above said conveyor adapted to feed closure caps to the tops of containers being moved therebelow by said conveyor, a pair of elongated spaced rails positioned generally parallel to said path to engage opposite sides of the tops of closures on said containers, one of said rails adapted to apply greater friction than the other to provide a light closure rotating force to rotate the closures into initial engagement with the container threads, an endless belt positioned above said conveyor and having a lower run aligned to move in the direction of said conveyor, a drive for said endless belt adapted to move it at a given speed, a shoe mounted adjacent said endless belt and above said conveyor and generally parallel to the lower run of said endless belt and restrained against movement laterally and longitudinally of said conveyor, said endless belt positioned to engage oll-center portions of the closures on said moving containers and said shoe positioned to engage opposite ofli-center portions of said closures to screw them on containers.

7. The machine as claimed in claim 6 in which the lower portion of the shoe slopes downwardly from its front and rear ends to a central generally horizontal sealing portion.

8. The machine as claimed in claim 7 in which the lower strand of the endless belt is forced downwardly by a member having a lower surface similar to the lower surface of said shoe.

9. In a sealing machine for sealing containers with caps of ferrous metal the combination of an inclined cap chute, a leveling plate pivotally mounted on the end of said chute, and a magnetized wheel intermediate the chute and the leveling plate to magnetically engage the tops of the caps and move the caps from said chute to said leveling plate.

10. In a sealing machine the combination of an inclined cap chute, a leveling plate pivotally mounted on the end of said cap chute, a magnetized wheel rotatably mounted intermediate the shoe and the leveling plate to magnetically engage the tops of caps to transfer them from said shoe to said leveling plate, and a coaxing plate on the end of said leveling plate mounted for movement vertically with regard to said leveling plate and having a plurality of cap leveling rails thereon adapted to apply a relatively light downward force to caps leaving said leveling plate.

11. In a sealing machine, the combination of an inclined cap chute, a generally horizontal leveling plate pivotally mounted on the end of said chute, a magnetized wheel rotatably mounted intermediate the chute and the leveling plate, a magnet on said leveling plate adapted to support caps transferred thereto by said magnetized wheel, and a coaxing plate at the end of said leveling plate connected for movement vertically with regard to said leveling plate and having a capretarding friction member thereon positioned to engage an offcenter portion of caps.

12. In a sealing machine, the combination of a conveyor for containers, an inclined chute positioned above said conveyor to present the lowermost closure therein to the top of a container moving therebelow on the conveyor, a leveling plate pivotally connected to said chute and having a generally horizontal magnetized lower surface adapted to level and support closures drawn from said chute onto the container mouths, a magnetized wheel rotatably mounted intermediate said chute and said leveling plate and adapted to support closures being moved by a container from the chute to the leveling plate, a coaxing plate at the free end of said leveling plate and said chute, and closure rotating means on said coaxing plate positioned to engage an oil-center portion of the closures.

13. In a sealing machine the combination of a horizontally disposed container conveyor, an inclined cap chute positioned above said conveyor to present the lowermost closure therein to the top of a container moving therebelow on the conveyor, a pivotally mounted leveling plate having a generally horizontal magnetized lower surface adapted to level and support closures drawn from said chute by the container months, a magnetized wheel rotatably mounted intermediate said chute and said leveling plate and adapted to suspend closures being moved by a container from the chute to the leveling plate, a coaxing plate at the free end of said leveling plate and pivotally mounted for vertical motion with respect to said leveling plate and said chute, closure rotating means on said coaxing plate positioned to engage an off-center portion of the closure tops to provide an initial engagement between the threads of the closure cap and the container, a pair of sealing members positioned above the conveyor beyond said coaxing plate to engage opposite off-center portions of the closure caps, one of said sealing members comprising an endless belt movable in the direction of the moving containers, the other sealing member comprising a stationary shoe.

14. The method of applying a screw cap to a container which comprises the steps of loosely threading the cap to the top of the container, and thereafter moving the container to carry an off-center portion of the top of the cap into sliding frictional engagement with an elongated stationary member and an opposite ofi-center portion into frictional engagement with a moving endless belt, moving said endless belt at a speed greater than the speed of the moving container and in the same direction, and simultaneously applying downwardly directed pressure against the cap top by said stationary member and said belt member.

15. The method as claimed in claim 14 in which said pressure is intense and is applied for a very short period.

16. In a sealing machine for applying caps to containers the combination of an inclined cap chute, a cap leveling plate pivotally mounted on the end of said chute, a magnetized wheel rotatably mounted intermediate said chute and said leveling plate to engage the tops of caps and to transfer them from said chute to said leveling plate, and said magnetized wheel comprising spaced circular plates of magnetic material engaging the opposite poles of a plurality of magnets, and said magnets having their north poles adjacent the same one of said plates and their south poles adjacent the other of said plates.

17. In a sealing machine for applying caps to containers the combination of an inclined cap chute, a cap leveling plate pivotally mounted on the end of said chute, a magnetized wheel rotatably mounted intermediate said chute and said leveling plate to engage the tops of caps and to transfer them from said chute to said leveling plate, and said magnetized wheel comprising a nonmagnetic disc-like center portion mounting one or more magnets, the opposite circular ends of said center portion having circular plates of magnetic material mounted thereon with a diameter greater than said disc and said magnet having its north pole adjacent one of said plates and its south pole adjacent the other plate.

18. In a machine for sealing containers with screw caps the combination of an endless belt positioned with its lower run engaging an oif-center portion of closure cap tops seated upon moving containers, drive means for said belt adapted to move the lower run in the direction of the moving containers, a braking member mounted adjacent said belt and having a friction surface for engaging and retarding opposite off-center portions of said closure cap tops, and pressure means resiliently urging said lower run of said belt and said braking member downwardly against the closure caps whereby said belt and said braking member cooperate to press said closure caps downwardly and to screw them into sealing engagement with containers.

References Cited in the file of this patent UNITED STATES PATENTS 1,664,514 Kramer Apr. 3, 1928 2,041,891 White May 26, 1936 2,072,245 Cuthhert et a1 Mar. 2, 1937 2,440,030 Thomas Apr. 20, 1948 2,630,959 Brown Mar. 10, 1953 2,876,605 McElroy et a1 Mar. 10, 1959 3,012,388 Stover Dec. 12, 1961

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