The present invention relates to machines for applying tamper evident bands and more particularly to a method and apparatus where the containers being supplied actually strip a cut band from a form which holds the banding material.

BACKGROUND OF THE INVENTION Tamper evident bands are used to seal and/or package containers and are extensively used in a wide variety of containment applications. They generally consist of a relatively thin plastic circular band. In some applications, they are placed circumferentially around the interface of a container and its associated lid. When the lid is moved, the band is disrupted, signaling that the container has been tampered with. Most consumer product packages that utilize screw-on or snap-on lids also use tamper evident bands to ensure that consumers receive unopened merchandise. Nearly all drug packages involving screw-on lids use tamper evident bands to ensure that the drugs have not been adulterated after packaging. In other applications, the band may be placed around two or more containers so that they are held together and unitarily packaged. Tamper evident bands are often used to effectively and efficiently package multiple articles even where

tampering is not a concern.

Application of tamper evident bands to a container or containers can be accomplished as follows. A tamper evident band supply strip in the form of a rolled, flattened tube is fed to a cutter. The cutter cuts the strip into individual flattened bands. The band is then engaged and held at one point by a point source grasping apparatus, usually a suction pod, such that the band droops downwardly expands to a generally circular shape. The container or containers are conveyed past the drooping band, and as a result of its placement, they engage and strip the same from the suction pod. Once the band has been stripped, the band and container pass beneath a slanted plate guide which forces the band down onto the container so that it properly circumscribes the container. The container or containers with the band are subsequently heat treated to shrink and secure the band.

While the basic steps of the method just described are theoretically cost effective and efficient in applying tamper evident bands, these steps have several significant drawbacks in practice.

One problem is the inability to adequately control the position of the band. The size of the band and the size of the container are usually very close and, in order for the application to be effective, they must be properly held and oriented relative to each other. The band itself is light-weight, flexible and, because it usually originates from a flattened and rolled state, tends to assume an irregular shape. Very often a point source grasping apparatus such as a suction pod or cup allows the band to droop in a position that is out of proper alignment with the oncoming container. Moreover, static electricity inherent in the band inhibits the band from expanding properly. If the band and container are not properly oriented, the application fails. This problem is even more pronounced when the container and band are larger

and therefore harder to control. There exists a need for an improved cost-effective and efficient means for positively orienting the band with respect to the path of the container. Another problem inherent in the use of a point source for engaging the band is the tendency for the suction pod to inadequately grasp the band. The band must somehow be pushed up against the suction pod to aid in the grasping process. The nature of the plastic band further compounds the problem. The surface of the band does not always conform to the surface of the pod. This can present a problem because the band must be positively attached to the vacuum pod. Because the band is formed of thin plastic and originates as a flattened roll, it tends to have a relatively large amount of static electricity. In particular, the static electricity tends to cause segments of the band to "cling" together and resist opening. Therefore, there exists a need for an improved grasping system which positively directs the band against the suction pod and which neutralizes the static electricity associated with the band such that the band will open and droop relatively long.

As previously mentioned, tamper evident band application machines generally utilize a plate guide to ultimately position the band onto the container. The plate guide is usually stationary. Some attempts have been made to positively press down the band with the plate guide, being moved up and down by a spring loaded plate. Because the ultimate position of the band on the container is both aesthetically and functionally important, there exists a need for an improved plate guide which will efficiently and cost-effectively position the band on the container. SUMMARY AND OBJECTS OF THE INVENTION

The present invention is an improved apparatus for applying tamper evident bands to a container which efficiently and cost-effectively

reduces or eliminates the above described problems inherent in prior tamper evident band application machines. To enhance control of the band position, the present invention uses an independent, hollow form for receiving the band from the point source suction pod and for continuously retaining the band about the interior area of the form and in proper alignment until it is stripped away by a passing container. To aid in engagement of the band with the suction pod, the present invention utilizes a timely ionized air blast from a nozzle positioned opposite the suction pod which serves to push the cut band towards the suction pod while simultaneously neutralizing the static electricity inherent in the band. In order to more effectively position the band on a container, the present invention uses a plate guide equipped with a vibrator mechanism to aid the band in sliding into position on the container.

It is therefore an object of the present invention to provide an improved ^" tamper evident band application machine which is capable of effectively and efficiently applying tamper evident bands to containers.

.Another object of the present invention resides in the provision of a tamper evident band application machine having a form that enhances control of band position and thereby facilitates the accurate placement of the band on a container.

Another object of the present invention resides in the provision of a timely ionized air blast to facilitate the engagement of the band with a point or limited area suction source.

Another object of the present invention resides in the provision of a vibrator equipped plate guide to positively urge the band into accurate placement on a container.

It is an object of the present invention to provide an improved tamper evident band application

apparatus that has the capability to handle relatively large bands and particularly to hold and position these bands to be stripped by containers themselves.

A further object of the present invention resides in the provision of a holding mechanism that encompasses the band and thereby shapes and holds it at a multiplicity of points rather than holding it at a single point as in conventional methods.

A further object of the present invention resides in the provision of a tamper evident band application apparatus of the character referred to above that utilizes a suction pod transfer device in conjunction with the aforementioned form-type holding mechanism. It is a further object of the present invention to provide a tamper evident band application machine with means for electrically neutralizing the cut band such that the static electricity associated with the band material will not adversely effect the subsequent handling of the band.

It is an object of the present invention to provide tamper evident band application machine that is provided with a cut band transfer and application sub¬ system that is effective to transfer the cut band from the cutting sub-system to the container with more positive control over the band from the cutting sub¬ system to the container.

It is an object of the present invention to provide a transfer application sub-system which is capable of precisely aligning and orienting the cut band in a stationary holder such that the cut band can be stripped from the holder by a passing container.

Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of the tamper evident band application machine of the present invention with a side panel removed to better illustrate the structure of the same.

Figure 2 is a back elevational view of the tamper evident band application machine of the present invention with a portion removed to better illustrate the threading, of the supply strip into the machine. Figure 3 is a fragmentary perspective view showing the cut band transfer and application sub¬ system of the present invention.

Figure 4 is a fragmentary perspective view showing the transfer and application sub-system of the present invention wherein the form engages.

Figure 5 is a top plan view of the form which forms a part of the transfer application sub-system of the present invention.

Figure 6 is a side elevational view of the form which forms a part of the transfer and application sub-system of the present invention.

Figures 7-13 are a series of schematic sequence views illustrating the transfer of a cut band from the cutting sub-system to a passing container. Figure 14 is a block diagram showing the control sub-system for the cut band application machine of the present invention.

Figure 15 is a perspective view of an alternate design for the suction pod of the present invention.

Figure 16 is a perspective view of a second alternate design for the suction pod of the present invention.

Figure 17 is a side elevational view of the suction pod shown in Fig. 16.

Figure 18 is a side elevational view of a suction pod and integral ledge assembly used for receiving and holding a cut tamper evident band.

Figure 19 is a perspective view of the suction pod and integral ledge assembly shown in Fig. 18.

Figure 20 is a top plan view of the suction pod and ledge assembly shown in Figs. 18 and 19.

Figure 21 is a perspective view of an alternate design for the form of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved machine for applying tamper evident bands to containers. Machines for applying tamper evident bands are well-known in the prior art and are used throughout the world for applying tamper evident bands to a wide variety of containers. For examples of typical machines for applying tamper evident bands, one is referred to the disclosures found in U.S. Patents 4,914,893; 2,623,673; 2,751,735; and 3,802,152, these disclosures being expressly incorporated herein by reference. Therefore, in describing the machine of the present invention for applying tamper evident bands, it will be appreciated that much of the structure and function of the machine is conventional. For that reason, a detailed description of the entire machine will not be dealt with herein in detail. With further reference to the drawings, the machine for applying tamper evident bands is indicated generally by the numeral 10. Forming a part of the machine 10 is a housing structure 11 that generally encloses the basic working parts of the machine. Machine 10 of the present invention comprises four basic sub-systems, a feed sub-system 20, a cutting sub¬ system 100, a transfer and application sub-system 200, and a control sub-system 300. Briefly viewing each of the sub-systems before proceeding with a detailed description of the invention, it should be pointed out that the feed sub-system 20 functions to direct and advance an elongated strip of band material 38a to the cutting sub-system 100. Cutting sub-system 100 cuts

the supply strip 38a into individual cut bands 38b that are ultimately applied to containers. Once cut, each cut band 38b is engaged by the transfer and application sub-system 200. Transfer and application sub-system 200 functions to grasp the cut band 38b and to position the same for an efficient transfer onto a passing container. All of the aforementioned sub-systems are integrally controlled by a conventional control sub¬ system 300. -A more detailed description of each sub- system follows.

Now with respect to the feed sub-system 20 and figures 1 and 2, it is seen that the housing 11 is provided with an exterior spindle plate 22 which supports a band supply roll 38. A supply strip 38a is pulled from the band supply roll 38 and trained around a lower idler 89 (Fig. 2) and extended upwardly to were the supply strip 38a is threaded between two turn rollers 90. From turn rollers 90, the supply strip 38a is fed through a series of plates 91 and then around another turn idler 92. Once supply strip 38a has been turned around to idler 92, the same is directed through two pairs of idlers 94 and 96. Idlers 94 and 96 are paired such that the upper two idlers 94 are turned at an a of 90° with respect to the lower two idlers 96. Lower idlers 96 tend to form a pair of creases about opposite flat sides of supply strip 38a. It is appreciated that due to the nature of the band supply 38 that the supply strip 38a would include natural creases about opposed vertical sides of the strip as viewed in Fig. 1.

Disposed below the lower idler rollers 96 is a pair of feed or drive rollers 28. Supply strip 38a is threaded through feed rollers 28 and is gripped therebetween. Feed rollers 28 are driven by a motor 40 that includes an output drive sheave 41 that drives a driven sheave 43 through belt 45. Driven sheave 43 is coupled directly to one of the feed rollers 28 and acts to drive the same. Feed rollers 28 includes a meshed

gear arrangement (not shown) that results in the driven roller actually driving the other roller in counterrotating fashion.

As seen in Fig. 1, the supply strip 38a is threaded with a device that is referred to us as a bullet 36. Bullet 36 is disposed with the supply strip 38a just above the upper idler rollers 94. Bullets are typically used in feeding sub-systems of conventional machines for applying tamper evident bands. As suggested in Fig. r, bullet 36 rest just above the upper rollers 94, and in fact is confined within the supply strip 38a by the rollers 94. Bullet 36 tends to condition the supply strip 38 such that the supply strip has a tendency, after passing around the bullet 36, to assume an open tubular shape for configuration. This, as will be appreciated from subsequent portions of this disclosure is important from the standpoint of preparing the banding material for application to containers. Cutting sub-system 100 is disposed below feed rollers 28 and functions to cut the supply strip 38a being fed downwardly thereto into a series of cut bands 38b. That is, motor 40 through a step controller progressively advances supply strip 38a downwardly into the cutting sub-system 100 which continues in a repeating fashion to cut bands 38b from the supply strip 38a.

With reference to Fig. 3 and the cutting sub¬ system 100, it is seen that the same includes a cutting block 104 that includes a lower wear plate 105. An elongated slit 106 is formed in the cutting block 104 and wear plate 105 and extends downwardly therethrough for permitting the supply strip 38a to pass therethrough. A cutting blade 102 is mounted below and closely adjacent wear plate 105. Blade 102 is moveable back and forth across slit 106 for the purpose of cutting the supply strip 38a into bands 38b. A carrier plate 108 is secured to the underside of blade 102

while blade 102 is connected and driven by a double acting air cylinder 204. Thus, through the control system, to be discussed subsequently herein, the double acting air cylinder 204 is controlled causing blade 102 to be moved back and forth across slit 106.

Disposed below the cutting sub-system 100 is the transfer and application sub-system 200. Transfer and application sub-system 200 functions to grasp the cut band 38b .and to hold the same and to effectuate transfer of the cut band 38b onto an underlying passing container C that is disposed on a conveyer system that passes adjacent the tamper evident band application machine 10.

Reviewing transfer and application sub-system 200 is more detail, the same includes a suction pod 202 that is secured to carrier plate 108 and is carried back and forth by blade 102. Thus, it is appreciated that suction pod 202 moves back and forth with blade 102 and is effectively controlled by the actuating of double acting air cylinder 204. ^' As illustrated in Fig. 3, suction pod 202 is formed at a complex angle. Suction pod 202 includes a front phase 203 that is angled downwardly. Also note that face 203 of suction pod 202 is V-shaped and includes a pair of suction openings, with a suction opening being formed in each side of the V-shaped face 204. In the preferred embodiment, the downward angle of the front face 203 is approximately 30° while the V-shaped angle of the face is approximately 15°. It is appreciated, however, that these angles can change depending on objectives and application. Extending from the rear suction pod 202 is a suction line 205 that is connected to a vacuum source (not shown) .

In Figures 15 - 17, there is shown two alternate designs for the suction pods. Figure 15 depicts a suction pod 202a that includes a pair of faces 202b and 202c separated by an elongated vertical slot 202d. Each suction face 202b and 202c includes a

suction opening that is connected to split manifolds 202e and 202f. The respective manifolds 202e and 202f join a central manifold 202g that is connected to a vacuum source. The provision of the elongated slot 202d permits a seam area of the cut band 38c to be received therein.

Turning to the alternate suction pod design shown in Figs. 16 and 17, it is seen that the suction pod 202h includes a suction line opening 202i. Pressed fitted into line 202i is a rubber suction tip 202j that projects from the front of the suction pod 202h. It is appreciated that suction tab 202j is effectively sealed within the pod 202h such that there is little or no leakage between .line 202i and the exterior of the suction tab insert 202j.

Positioned opposite suction pod 202 and fixedly mounted adjacent thereto is an air nozzle 206. Air nozzle 206 is connected to an air pump (not shown) through a connecting hose 206a. Prior to exiting air nozzle 206, air passing from the air pump to the nozzle passes through an electrical ionizer 210 which effectively removes the static from the cut band 38b being blasted by the air nozzle 206. It is appreciated that nozzle 206 is directed downwardly towards the face 203 of the suction pod 202. In effect, the air blast from nozzle 206 is directed against the cut band 38b that has just been cut or is in the process of being cut so as to urge the cut band 38b against face 203 of the suction pod 202. Thus, it is appreciated that the air blast dispersed from nozzle 206 increases the effectiveness of the transfer of the cut band from the cutting sub-system 100 to the suction pod 202. It should be appreciated that a plurality of air nozzles 206 could be used. Disposed below the suction pod 202 is a band receiving form 212 that is designed to receive a cut band 38b from the suction pod. As illustrated in the drawings, form 212 is comprised of a generally C-shaped

wall structure having an interior wall 212b, exterior wall 212a, and terminal edges 212e and 212f. Terminal edges 212e and 212f form a side opening 212c. Formed internally within the C-shaped wall structure is a central opening 212d. Central opening 212d and side open area 212c are shaped and sized so as to receive the particular cut band to be applied. As illustrated in the drawings, form 212 is disposed at an elevation with respect.to the suction pod 202 where the form 212 essentially has to pass through the plane of the suction pod 202. In order to accommodate this design feature, the form 212 is provided with a slot 212g that is formed in the upper rear side wall structure. This permits form 212 to be moved back and forth with respect to the suction pods 202 and actually permits the suction pod 202 to pass through the C-shaped wall structure of the form 212.

Form 212 includes a lower ledge 212h. As seen in the drawings, ledge 212h depends downwardly from the backside of form 212 arid is of a general L- shape. The lower portion of the ledge 212h includes a flat plat or frame that serves to support and hold a portion of the cut band 38b.

Form 212 is secured to an L-shaped bracket 217 that is in turn secured to a rod 215 that projects from a spring loaded single-acting air cylinder 214. Air cylinder 214 is maintained in a normal retracted position by a spring (not shown) associated with the cylinder 214 while the cylinder is extended by air directed into the same.

As illustrated in the drawings, disposed adjacent form 212 is a vibrating guide plate 220. Plate 220 is adjustably mounted by adjustable mounting assembly 224 that permits the plate structure to be moved up and down with respect to the underlying conveying system. Secured to plate 220 is a pneumatic vibrator 224 that imparts a relatively high frequency vibration to the plate structure 220. This vibrating

action assists the plate in effectively positioning a cut band 38b around the top of a container C passing underneath the tamper evident band application machine 10. As will be understood from subsequent portions of the disclosure, after a tamper evident band 38b has been applied to the top or neck of a container C, the band 38b and container pass under plate 220 and the plate is so spaced such that it generally engages the cut band 38b.disposed atop of the container C and assists in properly positioning the cut band 38b about the container as the container C passes underneath plate 220.

Forming a part of the overall control sub¬ system 300 is a photoelectric cell 304 that is secured to or adjacent vibrating plate 220.

Photo-cell 304 effectively senses the presence of a passing container C and in turn, controls (through the control sub-system 300) the movement of form 212 and blade 102 which in turn controls the movement of suction pod 202.

Disposed below the machine 10 is a conveyor system indicated generally by the numeral 400. Conveyor system 400 includes a frame structure 402 that has associated therewith a moving conveyor belt 404 that is designed to move container C (See fig. 1) from left to right underneath the cut band application machine 10. Also as indicated in Fig. 1, the conveyor 400 is provided with a side rail structure 406 for confining the containers C on the conveyor. Referring now to Fig. 14, control sub-system

300 of the present invention is shown therein in block diagram form. It should be pointed out that control sub-system 300 is of the same nature and characteristics as control sub-system 300 conventionally used in tamper evident band application machines. For this reason, a detailed discussion of control sub-system 300 will not be taken up here. However, for a more complete and unified understanding

of the present invention, the control sub-system 300 will be briefly described.

Referring to Fig. 14, it is seen that the central element of control sub-system 300 is programmable controller 310 which is adapted to receive input from cut control photoelectric cell 302 and container sensing photoelectric cell 304. Programmable controller 310 controls the operation of vacuum pump 312, step motor 40 solarnoids 314, and air pump 316. As shown in Fig. 1, supply strip 38a includes a series of spaced indicia marks 38c. Photoelectric cell 302 located adjacent supply strip 38a senses these indicia marks 38c and directs that information to programmable controller 310. As discussed later, programmable controller 310 responds by stopping step motor 40. This permits control sub-system 300 to control the height of respective cut bands 38b cut by cutting sub-system 100. Programmable controller 310 further responds to the input from photoelectric cell 302 by initiating an operation sequence which is discussed in greater detail hereinafter. In this sequence, programmable controller 310 controls the actuation of vacuum pump 312, air pump 316, and the actuation of double acting air cylinders 204 and 214 through solarnoids 314. In this way, programmable controller 310 controls the suction at suction pod 202, the air blast from air nozzle 206 and the fore and aft motion of suction pod 202, blade 102, and form 212. Photoelectric cell 304 secured to vibrating plate 220 senses the passing of containers C and directs this information to programmable controller 310. Programmable controller 310 responds to this input by running step motor 40 and sensing all other operations.

Turning to Figs. 18 - 20, an alternate design is shown for transferring the cut band 38b from the cutting apparatus onto a container C. In this case, there is provided a suction pod assembly with an

integral ledge or shelf support, indicated generally by the numeral 500. By providing an integral ledge to the suction pod assembly, the need for a form 212 is obviated. Thus, the suction pod and integral wedge assembly 500 shown in Figs. 18 - 20 serves to grasp the cut bands 38b and to retain and position the same for direct application to an underlying passing container C.

Viewing suction pod and integral ledge assembly 500 in more detail, it is seen that the same includes a slightly curved back plate 500 that includes a plurality of suction points in the form of suction cups 504 formed in the back plate 502. Secured to the lower portion of the back plate 502 and angled downwardly therefrom, as shown in Fig. 18, is an integral ledge plate or shelf support 506. The ledge plate 506 is particularly angled downwardly such that the right hand portion of the cut band 38b, as viewed in Fig. 18, droops downwardly so as to occupy a position in the path of a passing container C. It is appreciated that as the passing container C moves underneath ledge 506, the top of the container will engage the lower drooping portion of the cut band 38b and pull the same off ledge 506 as well as stripping the band 38b from the suction points or cups 504. It will be appreciated that the suction pod and integral ledge 500 can be moved back and forth and up and down by conventional fluid cylinder means. In the case of the suction pod and integral ledge assembly 500, it is desirable to provide a plurality of air jets 206 to assist in positively transferring the cut band 38b from the cutting assembly to the suction cups 504. This is especially true since the suction pod assembly 500 is designed to handle relatively large diameter bands. For example, the suction pod assembly and integral ledge 500, shown in Figs. 18 - 20, is particularly designed to handle tamper bands having a circumference of 400mm or more. It is appreciated that the suction

pod and integral ledge design 500 shown in Figs. 18 - 20 could in fact accommodate and efficiently handle tamper evident bands that are smaller in diameter than 400ml. Turning to Fig. 21, an alternative design is shown for the form 212. The embodiment of Fig. 21 is essentially the same as that already shown and described with the exception of the provision of a pair of outwardl .tapered wall portions 212i that projects forwardly from the mouth of the form 212. These tapered wall portions, which are sometimes referred to as "lead-ins", served to facilitate the transfer of the cut band 38b from the suction pod into the form 212 itself. Operation of the tamper evident band application machine is controlled by the programmable controller 310. The machine operates in cycles which begin with the feeding of the supply strip 38a and end with a complete engagement of a cut band 38b with a container C. A description of a single cycle follows. Such cycles may be executed over sixty times per minute, providing for quick and efficient tamper evident band application. Values hereinafter stated will vary with particular applications and depend on the size of the containers, properties of the tamper evident bands, and related parameters.

At the beginning of a cycle, step motor 40 is running and as a result supply strip 38a is pulled downwardly through slot 106 by feed rollers 28. At this time, the air and vacuum pumps are not actuated and blade 102 and suction pod 202 are fully retracted. (See fig. 7) This continues until cut control photo¬ cell 302 senses the next succeeding indicia strip 38c on supply strip 38a. At this time, the end of supply strip 38a protruding through slot 106 is equal to the desired band width.

When cut control photo-cell 302 registers the next succeeding indicia 38c, the programmable controller 310 signals the actuation of the vacuum pump 312 and cylinder 204 so that blade 102 and suction pod 202 extend towards slot 106 and a vacuum is generated at suction pod 202. As blade 102 fully extends, it cuts a band 38b and suction pod 202 simultaneously engages and holds this band by suction (fig. 8) . To aide suction pod 202 in making contact with cut band 38b, an air blast of approximately 0.2 to 1.0 second is directed against cut band 38b forcing it against suction pod 202 (fig. 9) . Because the air blast is ionized, it tends to neutralize the static electricity that is inherent in cut band 38b allowing the same to more readily expand to a generally circular shape and eliminating the repellence between cut band 38b and suction pod 202. Because front face 203 of suction pod 202 is V-shaped, it more easily engages cut band 38b by receiving a crease of the same in the apex of the V- shaped face.

Once cut band 38b is engaged and held by suction pod 202, suction pod 202 and blade 102 retract fully (fig. 10) . After a short delay (approximately 0.5 to 1.3 ms) to allow cut band 38b to expand, cylinder 214 is actuated and the rod 215 thereof extended so that form 212 moves forward. As form 212 moves forward, it receives cut band 38b through side open area 212c. As noted earlier, front face 203 of suction pod 202 is angled downward so that it holds cut band 38b at a downward angle. Form 212 is angled at approximately the same angle and thereby engages cut band 38b squarely within central opening 212d. Once encompassed by form 212, cut band 38b is held by substantial and continuous contact with interior wall 212b. As form 212 continues to extend forward, cut band 38b is stripped from suction pod 202 (fig. 11) . After form 212 with cut band 38b has been extended fully, a passing container C engages cut band 38b and

strips it from form 212 (figs. 12 and 13) . Because the cut band 38b is held at a downwardly sloping angle (Figs. 4, 11, and 12) the container C first engages the inner wall of cut band 38b so that a portion of cut band 38b surrounds the container C. Form 212 remains extended until container sensing photo-cell 304 senses a passing container C which generally corresponds with the stripping of cut band 38b. Once photo-cell 304 has detected the passing container C, then air cylinder 214 is allowed to retract and the next cycle begins.

After container C strips cut band 38d from form 212, it passes beneath sloped plate guide 220. Plate guide 220 gradually forces cut band 38b down onto the container until it is in an appropriate position. Vibrator 222 causes cut band 38b to be efficiently and accurately positioned upon the container C for subsequent heat treatment.

The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from ^' the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.