US3807122A

US3807122A - Bag holding apparatus and method for packaging

Info

Publication number: US3807122A
Application number: US00254075A
Authority: US
Inventors: L Kihnke; D Thompson
Original assignee: Dake Corp
Current assignee: Dake Corp; Oliver Healthcare Packaging LLC
Priority date: 1972-05-17
Filing date: 1972-05-17
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

A bag holder for packaging operations which removably supports a plurality of flexible bags preferably adjacent both a bag filling means and a fluid means for opening the bags prior to filling and for indicating the absence of bags on the holder. The bag holder comprises a support means including a frame, a removable wire wicket and a spring-biased back plate for urging the bags into filling position against the wicket. Associated with the springbiased plate is a fluid pressure sensitive signaling means which is actuable by a stream of air normally directed against the bags. When a supply of bags is on the wicket they prevent the signaling means from being actuated but when the supply of bags is exhausted the stream of air actuates the signaling means to indicate the supply of bags is exhausted. Another feature relates to means for pivoting the bag holder away from the bag filling means in order to facilitate the insertion of a fresh supply of bags on the holder.

Description

United States Patent [1 1 Kihnke et al.

[451 Apr. 30, 1974 BAG HOLDING APPARATUS AND METHOD FOR PACKAGING Inventors: Lee S. Kihnke, Spring Lake; Dewey L. Thompson, Grand Haven, both of Mich.

Dake Corporation, Grand Haven, Mich.

Filed: May 17, 1972 App]. No.: 254,075

[73] Assignee:

[56] References Cited UN lTED STATES PATENTS 2/1950 Anglo 116/37 2/1973 Fronczak 10/1969 Ness et a1. 116/65 X Primary ExaminerTravis S. McGehee Attorney, Agent, or FirmHeneveld, Huizenga & Cooper A bag holder for packaging operations which removably supports a plurality of flexible bags preferably adjacent both a bag filling means and a fluid means for opening the bags prior to filling and for indicating the absence of bags on the holder. The bag holder comprises a support means including a frame, a removable wire wicket and a spring-biased back plate for urging the bags into filling position against the wicket. Associated with the spring-biased plate is a fluid pressure sensitive signaling means which is actuable by a stream of air normally directed against the bags. When a supply of bags is on the wicket they prevent the signaling means from being actuated but when the supply of bags is exhausted the stream of air actuates the signaling means to indicate the supply of bags is exhausted.

Another feature relates to means for pivoting the bag holder away from the bag filling means in order to facilitate the insertion of a fresh supply of bags on the holder.

ABSTRACT 22 Claims, 5 Drawing Figures BAG HOLDING APPARATUS AND METHOD FOR PACKAGING This invention relates to means or apparatus for supporting a plurality of bags in a packaging machine and, more particularly, to a bag holding apparatus which removably supports a plurality of flexible bags preferably adjacent a bag filling means and a fluid means for opening the bags prior to filling and for indication when the bag holder is empty.

BACKGROUND OF THE INVENTION In the past, various apparatus for supporting and holding bags during packaging operations have been devised. Some of these prior bag holders have required the manual insertion and removal of individual bags before and after the filling operation. Others of the prior bag holders have held a plurality of bags such that individual bags may be opened, filled and removed without the individual insertion of additional bags. However, these latter support means have included no means for indicating the absence of any bags on the bag holder and thus, have not been able to prevent the operation of the packaging machine associated therewith when the bag holder is empty. Consequently, the utilization of the prior bag holders has required constant attention to the packaging machines associated therewith by human operators in order to prevent the waste and spillage of materials to be packaged when no bags are available and to maintain the constant operation of the machine.

Thus, no efficient and reliable apparatus was available for holding, opening and indicating the absence of any of a supply of individual flexible bags and which would automatically prevent the operation of an associated packaging apparatus when the bag holder was empty.

Further, the replenishing of bags on prior machines which held a supply of bags at one time was difficult and time consuming. Thus, even with the constant attention of the operator, valuable packaging time was lost merely in inserting a fresh supply of bags.

SUMMARY OF THE INVENTION Accordingly, it is an object and feature of the present invention to provide a bag holding, opening and removing apparatus for packaging machines which includes automatic means for indicating the absence of any bags on the bag holder and automatically prevents the operation of the packaging machine when the bag holder is empty.

It is another object and feature of the present invention to provide a bag holding, opening and removing apparatus for packaging machines having a fluid means for opening the individual bagsin preparation for their filling with the material to be packaged and a mechanical means for releasing the material to be packaged into the opened bag and for removing the bag from the bag holder.

It is a further object and feature of the present invention to provide a bag holder having a means for constantly urging the outermost bag in a supply of bags into the proper position for filling and removal from said bag holder.

It is yet another object and feature of the present invention to provide a bag holder having pivotal securing means for pivoting the bag holder into a position facilitating the insertion and removal of hanger means including a plurality of bags.

The object and attendant advantages of the present invention may be accomplished by providing a bag holder for packaging machines comprising a support means for holding a plurality of bags adjacent a filling means for filling the bags with material to be packaged. The support means comprises a bag frame pivotally mounted on a portion of the frame for the packaging machine and includes a rear support plate and means mounted perpendicularly thereto for removably holding a hanger means which carries the plurality of bags. The bags hang from the hanger means and rest on a spring-biased back plate which is slidably mounted perpendicularly to the rear support plate such that the back plate constantly urges the plurality of bags against a cross member included on said hanger means thereby forcing the plurality of bags away from the rear support plate. The outermost bag on the plurality of bags is thus held in the proper position adjacent the filling means in ready-to-fill position. A retaining plate is removably mounted on the hanger supporting means in order to retain the hanger means and the plurality of bags in their proper position. The support means also includes a pivotal securing means which is slidably secured in a slotted member mounted on the packaging apparatus frame which may be selectively secured or released to allow the pivotal movement of the bag frame away from the filling means thereby facilitating the removal of the retaining plate and the hanger means in order to refill the bag holding apparatus.

The bag holding apparatus further includes an aper ture in the biased back plate which is connected with a fluid pressure-sensitive signaling means. When no bags are held by the bag holder, a fluid means, including a nozzle directing a stream of compressed air at the aperture, directs the stream of air into the aperture, thereby activating the fluid pressure-sensitive signaling means which indicates the absence of any bags and prevents the filling means from releasing any material to be packaged. The fluid means also works in cooperation with the filling means adjacent the bag holding apparatus in order to open the outermost bag held by the bag holding apparatus prior to the filling operation.

These and other objects, advantages and features of the invention will become apparent from a study of the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side elevation of the bag holding apparatus in combination with a packaging apparatus;

FIG. 2 is a front elevation of the bag holding appara tus in combination with the packaging apparatus taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary side elevation of a portion of the apparatus shown in FIG. 1;

FIG. 4 is a fragmentary perspective view of a portion of the bag holding apparatus; and

FIG. 5 is a fragmentary side elevation similar to FIG. 1 but showing the bag holding apparatus pivoted to a position for receiving a fresh supply of bags.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in greater detail, FIG.

1 shows the bag holding apparatus in combination with a packaging apparatus including a filling means 60 and an infeed conveyor means 90. Generally speaking, support means or bag holding apparatus 10 is supported between

frame members

11 and 12 which form a portion of the frame structure which also supports filling means 60. Bag holder is disposed at an angle with the vertical generally beneath the lower end of the filling means such that the outermost bag 14 included in a plurality of bags 16 is properly positioned to be opened and removed by a fluid means 50 and filling means 60.

The filling means 60 which comprises a portion of the packaging apparatus used in conjunction with the bag holding apparatus 10, is of the type described in the concurrently filed application entitled PRODUCT PACKAGING APPARATUS invented by Lee S. Kihnke, Ser. No. 254,074, filed on even date herewith and incorporated by reference herein. Generally, the packaging apparatus includes a scale 62 having counterbalancing means or weights 63 which allows a predetermined weight to be set on scale 62 such that a certain predetermined amount of material to be packaged may be dispensed into bag 16 by filling means 60. Scale 62'provides a supportifor filling means 60 suspended therefrom by means of frame 64. The filling means 60 comprises a bucket 65 having an upper opening 66 disposed adjacent the discharge end 92 of infeed conveyor means 90, and a lower end 67 disposed adjacent bags 16. Hingedly mounted on bucket 65 is a mechanical means or cover plate 70 which pivots about rod 71.

Fluid power means including two

air cylinders

72 and 74 mounted end to end provide power for opening cover plate or door 70 to a first open position 75 and a second open position 76. First and second

open positions

75 and 76, shown by the phantom lines in FIG. 1, respectively allow the material'to be packaged held in bucket 65 to be released into the awaiting outermost bag 14 (shown by the phantom lines in FIG. 1) and cause the filled bag to be removed from the bag holding apparatus 10 respectively. Prior to the filling and removal of the bag 14, fluid means 50 opens bag 14 by means of a stream of compressed air aswill be described more fully below.

Cooperating with filling means 60, is the infeed conveyor means 90, described in the concurrently filed application I entitled PACKAGING APPARATUS, invented by Lee S. Kihnke, Ser. No. 254,076, filed on even date herewith and incorporated by reference herein. As partially shown in FIG. 1, conveyor means 90 includes a discharge end 92, flow diverting gates 94, and a recirculating conveyor means 96. The infeed conveyor means 90 feeds a flow of material to be packaged to bucket 65 until a predetermined quantity of the material has been deposited in the bucket, when scale 62 signals that the predetermined weight has been reached. This signal causes flow diverting gates 94 to divert the flow of material from bucket 65 to recirculating conveyor 96 thereby preventing any waste and spillage of the material. Therefore, infeed conveyor means 90 and filling means 60 work in cooperation with support means or bag holder 10 and fluid means 50 to provide a complete product or material packaging apparatus which can automatically open, fill, and remove a supply of bags 16 held by the bag holding apparatus 10 Referring now to FIGS. 1 through 5, the construction and operation of the novel support means or bag holding apparatus 10 will now be described. Bag holding apparatus 10 is mounted on frame member 11 by means of support members 18 which include a support arm 19 (FIG. 3). Fastening means such as bolts 20 may be used for this purpose. Bag frame 22 is pivotally mounted on support arm 19 by means of pins 23 and pivot members 24. Bag frame 22 includes a rear support plate 25 including wicket or hanger receiving elements 26 mounted perpendicularly thereon. A backing means or back plate 27 is slidably mounted on rods 28. The back plate 27 is biased by springs 29 such that plate 27 is parallel to rear support plate 25 but is constantly urged against the plurality of bags 16 mounted on bag holding apparatus 10.

The plurality of bags 16 is fastened to bag frame 22 by means of a hanger means or wicket 30. Wicket 30 includes two parallel legs 31 extending from and interconnected by a bight portion or cross member 32, which serves to restrain bag 16 when the wicket is in place in elements 26. Each of the plurality of bags 16 includes two apertures 33 which receive legs 31 when the bags are placed thereon.

Bags 16 each include a flap 15 which is adjacent to and extends beyond the opening 17 in each bag. Thus, when a plurality of bags 16 are stacked on wicket 30 by means of apertures 33 provided in flaps 15, and the wicket 30 is mounted in apertures 34 provided in wicket receiving elements 26, the opening 17 of the outermost bag 14 will be in a position immediately below the opening 67 of bucket 65. The outermost bag 14 is prevented from sliding off legs 31 by cross member 32, and the entire wicket and bag assembly when mounted in apertures 34 is prevented from moving by means of a removable restraining means or securing plate 35 mounted on elements 26 by means of slots 36 and fastening means 37. As shown in FIG. 4, a right angle extension 38 on securing plate 35 contacts cross member 32 of wicket 30 and securely holds the wicket in place in apertures 34. Apertures 34 may be provided with grommets 39 or other liners in order to provide a frictional engagement of legs 31. Wicket 30 may thus be slidably inserted in apertures 34 and securely held by grommets 39.

As shown in FIGS. 1, 2 and 5, the'support means includes a securing means comprising a securing arm 40 pivotally mounted on pin 45, the lower portion of rear support plate 25 and cooperating with a slotted member 41 such that the entire support means 10, including bag frame 22, may be selectively secured or released to pivot about pins 23 in an arc downwardly and away from bucket 65. Securing arm 40 is threaded and receives two nuts 46..Nuts 46 may be moved along the length of arm 40 to provide an adjustable space along the arm for receiving slotted member 41. Thus, the position of nuts 46 on arm 40 determines the angle at which the plurality of bags 16 supported on bag frame 22 is held beneath filling means 60. When the last of the plurality of bags 16 has been removed from bag holding apparatus 10, securing arm 40 may be released from slotted member 41 thereby allowing bag frame 22 to pivot away from filling means and allowing the removal of securing plate 35 and empty wicket 30, as shown in FIG. 5. A fresh supply of bags carried on a separate wicket 30 may then be inserted in apertures 34 and secured in place by plate 35.'The bag frame may then be pivoted back to its operational position and secured in place by means of securing arm 40.

Cooperating with bag holding apparatus 10, is fluid means 50 as described in the co-pending application, Ser. No. 254,074, referred to above. Fluid means 50 comprises a conduit or tube 51 having a fluid flow directing means or nozzle 52 at the end thereof. Conduit 51 is connected to a main air supply, a portion of which is shown in FIG. 1 at 53. Nozzle 52 is positioned so as to direct a stream of compressed air from air supply 53 past the lowermost extremity of mechanical means or cover plate 70. A portion of the stream of compressed air will be deflected by cover plate 70 towards opening 17 of the outermost bag 14 thereby opening and filling the bag with air. Upon a signal given by scale 62, as described above, the cover plate 70 will then be pivoted into its first open position 75, as described above, and cover plate 70 will swing into the already open bag 14 thereby allowing material to be packaged to slide from bucket 65 into bag 14. The cover plate 70 may then be moved to its second open position 76, as also described above, which movement forceably removes bag 14 from flag 15 along the perforated line shown in FIG. 4 and allows the filled bag to drop into a waiting receptacle positioned below the bag holding apparatus. This operation will be repeated by the filling means 60 a number of times until all of the plurality of bags 16 have been used. The removal of the last bag from bag holding apparatus 10 allows the operation of an additional feature as described below.

The additional operation comprises a method for detecting the absence of bags on the bag holding apparatus and for stopping the dispensing of material when the absence of any bags is detected. When the last bag 14 has been urged into position by biased backing plate 27, filled and removed by filling means 60 and cover plate 70, an additional portion of the fluid means 50 or an indicating means mounted on bag holding apparatus 10 is activated. Back plate 27 includes an aperture or port 42 which is connected to a fluid pressure sensitive signaling or switch means 43 mounted on rear support plate 25 by a communicating or flexible tube 44. Port 24 is positioned in back plate 27 directly in line with the stream of air flowing from nozzle 52 past the lowermost extremity of cover plate 70 such that, when the last bag 14 has been removed from apparatus 10, the flow of compressed air will directly enter port 42. A bag in position as supported by apparatus 10 normally blocks the flow of air with its. exposed side. However, when the bag is absent, air will enter port 42 which is positioned on the opposite side of the normal bag position. The entering of the flow of compressed air into port 42 causes an increase in fluid pressure in communicatin g or flexible tube 44 which in turn expands a bellows (not shown) in fluid pressure sensitive signaling or switch means 43 thereby closing a switch (not shown). The closing of the switch in fluid pressure sensitive signaling means 43 activates a bag-empty or no-bag electrical signaling circuit (not shown) which in turn activates and diverts gates 94 across the flow of material on infeed conveyor 90 thereby preventing material from entering bucket 65 and being released bycover plate 70. An indicating light is also turned on by signaling means 43 to visually alert the packaging apparatus operator that the bag holder is empty. Consequently, it will be understood that the indicating means comprising port 42, signaling means 43 and tube 44, in combination with the remainder of fluid means 50, comprise a means for indicating the absence of any bags on bag holding apparatus 10. This indicating means prevents the operation of the packaging apparatus until a fresh supply of bags is inserted on bag holder 10 and the bagempty signaling circuit is manually shut off.

- Therefore, it will be apparent that the bag holding apparatus or support means 10, in combination with the fluid means 50, provides a novel and useful means for supporting a plurality of bags in a packaging machine or apparatus. The bag holder and fluid means both insure the continuous and efficient operation of the packaging apparatus as a whole and yet, control the operation of the packaging apparatus when the bag holders supply of bags is exhausted. Thus, the efficient and automatic operation of the packaging apparatus is insured since the bag holding apparatus and fluid means will prevent the waste and spillage of the material to be packaged when no bags are left on the bag holding apparatus. It will also be observed that the bag holding apparatus 10 may be utilized to secure many types of flexible bags although in its preferred embodiment, its use is designed for lightweight, flexible plastic bags such as those used in the food processing industry.

While one form of the invention has been shown and described, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiment shown in the drawings and described above, is merely for illustrative purposes, and is not intended to limit the scope of the invention which is defined by the claims which follow.

The embodiments .of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A bag holding apparatus for packaging machines comprising in combination: support means for holding removable bags adjacent a bag filling means; and fluidoperated switch means for indicating the absence of said bag on said support means; said switch means including means for directing a stream of fluid against one surface of a bag when held by said support means and means responsive to said fluid flow for preventing operation of a packaging machine when said bag is absent, said responsive means being located in registry with said fluid flow and adjacent a surface of said bag opposite said one surface when said bag is held on said support means.

2. A bag holding apparatus for packaging machines comprising in combination: support means for holding removable bags adjacent a bag filling means; and fluid operated switch means for indicating the absence of said bag on said support means; said support means comprising a frame for supporting said bags in a position immediately adjacent said bag filling means, hanger means for removably mounting said bags on said frame, and backing means for constantly urging said bags into said position immediately adjacent said filling means.

3. A bag holding apparatus as described in claim 2 wherein said fluid operated switch means comprises fluid flow directing means and fluid pressure sensitive shut-off means, said fluid flow directing means being positioned to direct a fluid flow against bags supported against said backing means and into said fluid pressure sensitive shut-off means for actuating the same.

4. A bag holding apparatus as described in claim 3 wherein said hanger means comprises a U-shaped wire wicket, said U-shaped wire wicket having two, parallel leg portions each having one of their ends extending in a direction toward the plane of said backing means and their other ends interconnected by a bight portion; said bight portion preventing bags being on said legs from sliding off said wicket legs when said wicket is mounted on said frame; said backing means including a springbiased back plate for constantly urging bags being on said legs against said bight portion so as to position the tops of the bags in position to be opened by said fluid flow directing means.

5. A bag holding apparatus as described in claim 4 wherein said fluid flow directing means comprises a nozzle directing a flow of compressed air.

6. A bag holding apparatus as described in claim 3 wherein said fluid pressure sensitive shut-off means comprises an aperture formed in said backing means in line with said flow of compressed air, an expandable fluid servo unit including an electrical switch and a flexible tube connecting said aperture with said servo unit such that, in the absence of bags on said wicket,

- said flow of compressed air will enter said aperture, be

communicated by said tube to said servo unit, and actuate said servo unit, thereby closing said electrical switch.

7. A bag holding apparatus as described in claim 4 wherein there is provided wicket support means for removably supporting said wicket on said support means and pivot means for selectively pivoting said support means and said wicket support means out of their normal position in which they support bags in a ready-tofill position whereby said wicket may be removed from said wicket support means and another of said wickets, including at least one bag, may be mounted on said frame.

8. The bag holding apparatus of claim 7 in which the support means is pivoted at its upper end and a locking means is provided at its lower end for locking the support into ready-to-fill position; said locking means being releaseable for permitting'pivoting of said support means about said pivot means.

9. Apparatus for opening bags and indicating the absence of bags on a bag holder for packaging machines comprising fluid flow directing means for directing a stream of fluid toward a bag holder and for opening and positioning the mouth of a bag on said holder for receiving material to be packaged from a packaging machine; and fluid pressure sensitive signaling means including means responsive to the pressure of said stream of fluid for providing a signal indicating when said bags are absent; said flow being directed by said directing means such that when saidbags are supported on said holder, said stream will open and position said bag mouth, and when no bags are supported on said bag holder, said stream will activate said fluid pressure sensitive signaling means and indicate the absence of said bags.

10. Apparatus as described in claim 9 wherein said fluid flow directing means comprises a nozzle arranged to direct a stream of compressed air against the outermost bag supported by said holder such that said outermost bag is opened and filled with said air.

11. Apparatus for opening bags and indicating the absence of bags on a bag holder for packaging machines comprising fluid flow directing means, and fluid pressure sensitive signaling means, said fluid flow directing means adapted to direct a stream of fluid towardsaid bag holder such that when said bags are supported on said holder, said stream will open said bags, and when no bags are supported on said bag holder, said stream will activate said fluid pressure sensitive signaling means and indicate the absence of said bags; said fluid flow directing means comprising a nozzle arranged to direct a stream of compressed air against the outermost bag supported by said holder such that said outermost bag is opened and filled with said air; said fluid pressure sensitive signaling means comprising an aperture formed in said bag holder behind the area in which said bags are normally supported, an expandable fluid servo unit, and a flexible tube connecting said aperture with said servo unit, said aperture being in line with said stream of compressed air such that, in the absence of any bags on said holder, said stream of air enters said aperture, is transmitted to said servo unit by said tube, and actuates said servo unit thereby signaling the absence of said bags.

12. A bag holding apparatus for packaging'machines comprising a movable support means for holding a supply of removable bags adjacent a bag filling means; and securing means for selectively restraining and allowing movement of said support means whereby the insertion of a fresh supply of removable bags is facilitated; said support means being pivotally mounted adjacent a bag filling means; said securing means comprising a pivot arm and a fixed member separate from said support means, said pivot arm adapted to be selectively engaged and disengaged with said fixed member whereby said support means is allowed to pivot away from said bag filling means. in order to insert a fresh supply of bags.

13. A bag holding apparatus as described in claim 12 wherein said support means comprises a frame for supporting said bags in a position immediately adjacent said bag. filling means, hanger means for removably mounting said bags on said frame, and backing means for constantly urging said bags into said position immediately adjacent said filling means.

14. A bag holding apparatus as described in claim 13 wherein said pivot arm is pivotally mounted on said frame and said fixed'member is rigidly mounted on said bag filling means.

15. A bag holding apparatus as described in claim 14 wherein said pivot arm is adjustable such that said support means may be held in various positions relative to said bag filling means. I

16. A bag holding apparatus as described in claim 13 wherein said hanger means comprises a wicket removably insertable in apertures provided in said frame, said wicket adapted to support a supply of bags adjacent said bag filling means when in place on said frame, said support means being restrained adjacent said bag filling means by said securing means; said support means further including a retaining plate removably mounted on said frame for retaining said wicket on said frame; said securing means arranged to allow said support means to be pivoted away from said bag filling means whereby removal of said retaining plate and wicket is facilitated.

17. A bag holding apparatus as described in claim 16 wherein said wicket comprises a U-shaped wire wicket, said U-shaped wire wicket having two, parallel leg portions each having one of their ends extending in a direction toward the plane of said backing means and their other ends interconnected by a bight portion; said bight portion preventing bags being on said legs from sliding off said wicket legs when said wicket is mounted on said frame; said backing means including a springbiased back plate for constantly urging bags being on said legs against said bight portion so as to position the tops of the bags in position to be opened by said fluid flow directing means.

18. A bag holding apparatus as described in claim 17 wherein said support means is pivoted at its upper end and said securing means is provided at its lower end for restraining said support means in a ready-to-fill position.

19. In a method of packaging material comprising:

providing a bag for receiving material;

opening said bag with a stream of fluid;

depositing said material in said bag;

the improvement comprising detecting a stream of fluid in order to indicate the absence of a bag; said stream being directed against one side of said bag position when said bag is present; said stream being detected on the opposite side of said bag position when said bag is absent.

20. A method in accordance with claim 19 wherein said opening of said bag and said detecting of said stream of fluid are accomplished with the same stream of fluid.

21. A method in accordance with claim 19 wherein said detection of said stream of fluid initiates the stopping of said deposition of said material.

22. A bag holding apparatus for packaging machines comprising a pivotally movable support means for holding a supply of removable bags adjacent a bag filling means; and securing means for selectively restraining and allowing pivotal movement of said support means whereby the insertion of a fresh supply of removable bags is facilitated; said support means including a frame for supporting said bags in a position immediately adjacent said bag filling means, hanger means for removably mounting said bags on said frame, and backing means for constantly urging said bags into said position immediately adjacent said filling means.

Claims

1. A bag holding apparatus for packaging machines comprising in combination: support means for holding removable bags adjacent a bag filling means; and fluid-operated switch means for indicating the absence of said bag on said support means; said switch means including means for directing a stream of fluid against one surface of a bag when held by said support means and means responsive to said fluid flow for preventing operation of a packaging machine when said bag is absent, said responsive means being located in registry with said fluid flow and adjacent a surface of said bag opposite said one surface when said bag is held on said support means.

3. A bag holding apparatus as described in claim 2 wherein said fluid operated switch means comprises fluid flow directing means and fluid pressure sensitive shut-off means, said fluid flow directing means being positioned to direct a fluid flow against bags supported by said frame such that said fluid flow opens and fills said bags thereby properly positioning said bag means to receive material; and, in the absence of any bag means on said support means, directing said fluid flow against said backing means and into said fluid pressure sensitive shut-off means for actuating the same.

4. A bag holding apparatus as described in claim 3 wherein said hanger means comprises a U-shaped wire wicket, said U-shaped wire wicket having two, parallel leg portions each having one of their ends extending in a direction toward the plane of said backing means and their other ends interconnected by a bight portion; said bight portion preventing bags being on said legs from sliding off said wicket legs when said wicket is mounted on said frame; said backing means including a spring-biased back plate for constantly urging bags being on said legs against said bight portion so as to position the tops of the bags in position to be opened by said fluid flow directing means.

6. A bag holding apparatus as described in claim 3 wherein said fluid pressure sensitive shut-off means comprises an aperture formed in said backing means in line with said flow of compressed air, an expandable fluid servo unit including an electrical switch and a flexible tube connecting said aperture with said servo unit such that, in the absence of bags on said wicket, said flow of compressed air will enter said aperture, be communicated by said tube to said servo unit, and actuate said servo unit, thereby closing said electrical switch.

7. A bag holding apparatus as described in claim 4 wherein there is provided wicket support means for removably supporting said wicket on said support means and pivot means for selectively pivoting said support means and said wicket support means out of their normal position in which they support bags in a ready-to-fill position whereby said wicket may be removed from said wicket support means and another of said wickets, including at least one bag, may be mounted on said frame.

8. The bag holding apparatus of claim 7 in which the support means is pivoted at its upper end and a locking means is provided at its lower end for locking the support into ready-to-fill position; said locking means being releaseable for permitting pivoting of said supporT means about said pivot means.

9. Apparatus for opening bags and indicating the absence of bags on a bag holder for packaging machines comprising fluid flow directing means for directing a stream of fluid toward a bag holder and for opening and positioning the mouth of a bag on said holder for receiving material to be packaged from a packaging machine; and fluid pressure sensitive signaling means including means responsive to the pressure of said stream of fluid for providing a signal indicating when said bags are absent; said flow being directed by said directing means such that when said bags are supported on said holder, said stream will open and position said bag mouth, and when no bags are supported on said bag holder, said stream will activate said fluid pressure sensitive signaling means and indicate the absence of said bags.

11. Apparatus for opening bags and indicating the absence of bags on a bag holder for packaging machines comprising fluid flow directing means, and fluid pressure sensitive signaling means, said fluid flow directing means adapted to direct a stream of fluid toward said bag holder such that when said bags are supported on said holder, said stream will open said bags, and when no bags are supported on said bag holder, said stream will activate said fluid pressure sensitive signaling means and indicate the absence of said bags; said fluid flow directing means comprising a nozzle arranged to direct a stream of compressed air against the outermost bag supported by said holder such that said outermost bag is opened and filled with said air; said fluid pressure sensitive signaling means comprising an aperture formed in said bag holder behind the area in which said bags are normally supported, an expandable fluid servo unit, and a flexible tube connecting said aperture with said servo unit, said aperture being in line with said stream of compressed air such that, in the absence of any bags on said holder, said stream of air enters said aperture, is transmitted to said servo unit by said tube, and actuates said servo unit thereby signaling the absence of said bags.

12. A bag holding apparatus for packaging machines comprising a movable support means for holding a supply of removable bags adjacent a bag filling means; and securing means for selectively restraining and allowing movement of said support means whereby the insertion of a fresh supply of removable bags is facilitated; said support means being pivotally mounted adjacent a bag filling means; said securing means comprising a pivot arm and a fixed member separate from said support means, said pivot arm adapted to be selectively engaged and disengaged with said fixed member whereby said support means is allowed to pivot away from said bag filling means in order to insert a fresh supply of bags.

13. A bag holding apparatus as described in claim 12 wherein said support means comprises a frame for supporting said bags in a position immediately adjacent said bag filling means, hanger means for removably mounting said bags on said frame, and backing means for constantly urging said bags into said position immediately adjacent said filling means.

14. A bag holding apparatus as described in claim 13 wherein said pivot arm is pivotally mounted on said frame and said fixed member is rigidly mounted on said bag filling means.

15. A bag holding apparatus as described in claim 14 wherein said pivot arm is adjustable such that said support means may be held in various positions relative to said bag filling means.

17. A bag holding apparatus as described in claim 16 wherein said wicket comprises a U-shaped wire wicket, said U-shaped wire wicket having two, parallel leg portions each having one of their ends extending in a direction toward the plane of said backing means and their other ends interconnected by a bight portion; said bight portion preventing bags being on said legs from sliding off said wicket legs when said wicket is mounted on said frame; said backing means including a spring-biased back plate for constantly urging bags being on said legs against said bight portion so as to position the tops of the bags in position to be opened by said fluid flow directing means.

19. In a method of packaging material comprising: providing a bag for receiving material; opening said bag with a stream of fluid; depositing said material in said bag; the improvement comprising detecting a stream of fluid in order to indicate the absence of a bag; said stream being directed against one side of said bag position when said bag is present; said stream being detected on the opposite side of said bag position when said bag is absent.