US3561350A

US3561350A - Package binding machine

Info

Publication number: US3561350A
Application number: US753241A
Authority: US
Inventors: John Dorney; Colin Robinson
Original assignee: POWER IND Ltd
Current assignee: POWER IND Ltd
Priority date: 1967-08-16
Filing date: 1968-08-16
Publication date: 1971-02-09
Anticipated expiration: 1988-02-09
Also published as: NL6811728A; DE1786102A1

Abstract

In a package binding machine incorporating a nose plate to support overlapping ends of a loop of binding tape, during the sealing of the overlapping ends, the nose plate is movable between an operative position to provide a support for the overlapping ends of the tape during a sealing operation, and a retracted position in which it provides clearance for the ejection of the sealed joint from the machine.

Description

I United States Patent 1 1 3,56 1,350

1 Inventors Joh'n m [56] References Cited [71] A 1 N ggggfr Berkshm, gland UNITED STATES PATENTS i 5 3 331,312 7/1967 Leslie et a1 100/33X Pmemed Feb 9 197] 3,442,203 5/1969 Koblella 100/26 [73] Assignee Power Industri Li it d 3,442,732 5/1969 Sten saker et a1" 156/73 Berkshire. England 3,442,733 5/1969 Viicrns t i v 156/73 2 British company 3,442,734 5/196? Ericsson 156/73 [32] Priority Aug. 16, 1967, July 18, 1968 3,442,735 5/1969 Stensaker 156/73 [33] Gre B i Primary Examiner-Billy J. Wilhite l 37689/67 and 34212/68 Attorney-Scrivener, Parker, Scrivener and Clarke [54] PACKIAGE BINDING MACHINE ABSTRACT: In a package binding machine incorporating a 19 Claims, 6 Drawing Figs. 1

nose p ate to support overlapping ends of a loop of binding [52] US. Cl 100/29, tape, during the sealing of the overlapping ends, the nose plate lOO/33; 15 6/73 is movable between an operative position to provide a support [51] Int. Cl Bb 13/32 for the overlapping ends of the tape during a sealing opera- [50] Field of Search 100/4, 26, tron, and a retracted position in which it provides clearance for the ejection of the sealed joint from the machine.

PATENTED FEB 9197:

. 3561.350 sum 1 0M QR Qww PACKAGE BINDING MACHINE SPECIFK DESCRIPTION This invention relates to improvements in package binding machines and to a new or improved ejector mechanism for the release of a sealed loop of binding material from such a machine The invention is particularly suitable for use in a binding machine adapted to seal a loop of binding tape by friction welding of the overlapping ends thereof. In one machine of this type adapted to utilize polypropylene tape the ends of the loop are supported in overlapping relationship on a nose plate, and the upper tape is rubbed rapidly against the lower one for an interval of time and at a pressure sufficient to ensure fusion of the contacting surfaces to the tapes which are thereby bonded together to form a sealed joint. During the sealing operation the nose plate is interposed between the ends of the loop and a package around which the loop extends, and this member is required to provide firm support for these ends against the pressure exerted by the sealing device while permitting clean ejection of the sealed joint on completion of the sealing cycle.

According to the invention in a package binding machine including a nose plate arranged to support overlapping ends of a loop of binding tape during a package binding operation, and sealing means adapted to join together by friction welding upon the nose plate, the overlapping ends of the tape, the nose plate is movable between an operative position in which it provides support for the overlapping ends during operation of the sealing means and a retracted position in which it provides clearance for the ejection of the sealed joint from the machine. Preferably, when in the operative position the nose plate defines in the machine a closed passage through which the binding tape must be fed to form the loop.

The nose plate can conveniently be carried on a pivotal mounting to swing between the operative and retracted positions. In this case a suitable abutment is preferably provided to support the nose plate in the operative position against the pressure of the sealing means.

The machine may also be provided with a guide movable between an operative position in which it provides a continuous guide path for the tape through the nose plate until the ends of the tape have been brought into an overlapping relationship, and a retracted position to expose the overlapping ends of the tape to the sealing means adapted to join together by friction welding on the nose plate, the overlapping ends.

Where the machine is provided with such a guide, the guide is coupled to the nose plate by a lost-motion connection constructed and arranged to permit relative movement between the nose plate and the guide to take place by an amount sufficient to enable the guide to be moved independently of the nose plate between its operative and retracted positions, when the nose plate is in its operative position.

One embodiment of our invention is illustrated in the accompanying drawings in which:

FIG. 1 is a partly-sectioned elevation through a package binding machine;

FIG. 2 is a sectional plan on the line 2-2 of FIG. 1;

FIG. 3 is a view on the line 3-3 of FIG. 1;

FIG. 4 is a partly sectioned elevation showing, on an enlarged scale, the nose plate and gripper arrangement illustrated in FIG. 1;

FIG. 5 is an end elevation of FIG. 4; and

FIG. 6 is an inverted plan view of the nose plate and guide block illustrated in FIG. 5.

In the package binding machine illustrated in the drawings 10 is a casing which includes tape feeding and tensioning apparatus in the form of a primary tensioning device 11 and a secondary tensioning device 12. The tape feeding and tensioning apparatus forms the subject matter of our copending Pat. application Ser. No. 753,242, filed Aug. 16, 1968 and need not be described further herein. A base plate 13 of the casing 10 supports a frame 14 on which is carried, adjacent to the primary tensioning device 11 a free end gripper 15 formed, ad-

acent to its lower end. with an aperture l5a. The gripper 15 is pivotally connected to an intermediate point on a lever 16 one end of which is connected to a fixed pivot 16a on the frame 14 and the other end of which is connected to the piston rod 17 of a pneumatic cylinder G1. Extension or retraction of the cylinder G1 causes the gripper 15 to move away from or into engagement with a nose plate 18 associated with the base plate 13.

On the opposite side of the frame 14. but aligned with the free end gripper I2, is mounted a similar second gripper 19. The second gripper 19 is pivotally connected to an intermediate point on a lever 20 one end of which is connected to the piston rod 23 of a pneumatic cylinder G2. Extension or retraction of the cylinder G2 causes the gripper 19 to move away from or into gripping engagement with the nose plate 18.

The nose plate 18 comprises a flat metal plate pivotally carried on a pair of spaced levers 21 and movable between an operative position shown in FIG. 3, in which it is received in and supported by a transverse slot 22 in one end of the base plate 10, and a retracted position (not shown) in which it is disengaged from the slot 22 and pivoted away from the base plate 13. The levers 21 are carried on the fixed pivot 16a on the frame 10 which also forms the fixed pivot for the levers 16 and 20 for operating the grippers 1S and 19 respectively. The ends of the levers 21 remote from the nose plate 18 are coupled by a trunnion 24 which, at an intermediate point in its length, is connected to the piston rod 25 of a pneumatic actuator NP by means of which the nose plate 18 is moved between the operative and retracted positions.

Mounted on the frame 14 between the levers 21 and above the operative position of the nose plate 18 is a friction welding device. The friction welding device comprises a vibratory block 26 movable vertically upon actuation of a double acting pneumatic cylinder V carried on the frame 14. In the operative position the block 26 is urged towards the nose plate 18 by actuation of the cylinder and is vibrated at high frequency through an eccentric drive from an electric motor 27. Movement of the vibratory block 26 in a direction towards the nose plate 18 automatically energizes the motor 27 which then vibrates the block at a predetermined interval.

The nose plate 18 in its operative position provides a support against which the friction welding device operates in sealing the ends of a loop of package binding tape. To achieve high rigidity of the nose plate in this position it is desirable that the nose plate should be a close fit in the base plate slot 22, despite the tendency towards arcuate movement of the nose plate due to pivotal mounting of the levers 21.

The nose plate 18 is therefore pivotally mounted on the levers 21 and is resiliently urged (in a counterclockwise sense as seen in FIG. 3), for example by a torsion spring 28, towards a limiting position defined by abutments with the levers 21. When in the retracted position the nose plate 18 lies in its limiting position relative to the levers 21, this limiting position being such that as the nose plate is moved towards the operative position, its lowermost edge does not swing below the level of the underside of the base plate 13. The lower side of the mouth of the slot 22 is cut away, as at 29, to facilitate entry of the nose plate 18. The dimensions and relative positions of the parts are so selected that the nose plate enters the slot 22 with a substantially linear sliding action with little or no tilting movement relative to the slot.

As shown particularly in FIGS. 4 and 5 a metal block 30 of substantial length is positioned between the grippers l5 and 19 and is spaced at each end from an adjacent one of the grippers. The block 30 is relieved in its lower face at 31 between the end of the block adjacent to the gripper 15 and a vertical stop face 32 at an intermediate point in the length of the block. In an operative position the block 30 abuts against the upper surface of the nose plate 18. The block 30 is formed in the side adjacent to the frame 14 with a slot 33 extending between opposite ends of the block 30. The slot 33 is inclined with respect to the nose plate 18 in a direction such that it is aligned substantially between the aperture in the gripper l5. and the gripper 19 The block 30 extends beyond the plane of the

grippers

15, 19 in a direction away from the frame and is pivotally connected at this point to the free end of an arm 34 of a bellcrank lever 35 which is in turn pivoted at its midpoint to a fixed point 36 on the frame 14. The other arm 37 of the bellcrank lever 35 extends rearwardly between the grippers and at its outer end is urged upwardly by means of a tension spring 38. A second tension spring 39 acts between a pin 40 carried by the bellcrank lever 35 and the block to urge the block downwardly and into firm contact with the nose plate 18. At an intermediate point in its length the arm 37 carries a pin 41 which is received within an aperture 15b in the gripper 15. which aperture 15b is located above the aperture 15a.

A cutter comprising relatively movable spaced blades 42. 43 is located between the gripper 15 and an adjacent end of the block 30.

The block 30 is provided with a pin 44 which is received in an elongated opening or slot 45 in the nose plate 18 to form a lost motion connection therebetween. The slot 45 is positioned parallel to the direction in which the nose plate 18 and the block 30 are moved between their respective operative and retracted positions. and the length of the slot is chosen to permit the block 30 to be retracted independently of the nose plate 18 leaving the nose plate 18 in its operative position.

As shown in the drawings the machine is in an operative prsition with the grippers l and 19 raised, the vibratory b.0ck 26 retracted and the nose plate 18 and the guide block 30 in their operative positions.

By operation of the tape feeding and tensioning apparatus, the free end of a band of tape, suitably polypropylene tape, is fed from a supply through the aperture a in the free end gripper 15, between the

blades

42, 43 of the moving cutter and into the guide slot 33 in the block 30. Since the open face of the guide slot 33 is closely adjacent to the frame 14, there is no tendency for the tape to wander sideways out of the slot. The tape is then fed through the guide 33, and between the gripper l9 and the nose plate 18. The free end of the tape fed in this way is passed manually around a package to be bound or automatically around the package through a continuous track. 1 he free end of the tape is then passed between the free end gripper l5 and the nose plate 18, under the blade 43 of the moving cutter and between the lower relieved surface 31 of the block and the nose plate 18. This continues until the free end of the tape abuts the stop face 32 which acts as a dead stop, the tape having tripped a detector at a convenient point in the loop to switch off a motor driving the tape feeding and tensioning apparatus, and to actuate the pneumatic cylinder G1 which, in turn, causes the gripper 15 to move downwardly and grip the tape against the nose plate 18. The downward movement of the gripper 15 takes with it the pin 41 carried by the arm 37 of the bellcrank lever by engagement of the upper face of the aperture 15b with the pin 41 thereby moving the lever 35 angularly about the pivot pin 36 in a clockwise direction as indicated by the arrow in FIG. 5. As the angular movement of the bellcrank lever 35 takes place, since the guide block 30 is pivotally connected to the arm 34 of the bellcrank lever 35, the guide block 30 is withdrawn or swung clear relative to the nose plate 18, away from the line of the tape, although being maintained in abutment with the nose plate 18. The overlapping ends of the tape are thus freed from the constraint imposed by the slot 33 and the relief 31 and are freely positioned between the vibratory block 26 and the nose plate 18.

The binding tape is then retracted towards the supply and tensioned as described in our Pat. application Ser. No. 753,242, filed Aug. 16, 1968 by means ofthe primary tensioning device 11 and the secondary tensioning device 12.

When the required tension has been applied to the loop a pressure drop valve associated with the tensioning apparatus is operative to cause air to be supplied to the cylinder G2 to close the gripper 19 so that the tension in the loop is maintained by the

grippers

15 and 19. Simultaneously the pressure drop valve is operative to cause release of tension in the length of tape between the gripper 19 and the supply.

The pressure drop valve also actuates the vibratory block 26' to weld together the overlapping ends of the tape to form a permanent seal This is achieved by the block 26 producing a high frequency rubbing action between the ends ofthe loop to cause fusion ofthe material ofthe tape at their contacting surfaces. This action is continued at a pressure and for a duration sufficient to cause welding of the loop ends. and then terminated.

Simultaneously with the vibratory block 26 being brought into contact with the tape the moving

cutter blades

42, 43 are actuated to sever the sealed loop from the tape supply.

The

grippers

15 and 19 are then raised and the cylinder NP is actuated to move the nose plate 18 out of the slot 22 and towards the retracted position. As the nose plate 18 clears the slot 22 the tension in the sealed loop pivots the nose plate 18. and the guide block 30, downwards against the force in the torsion spring 28 so that the sealed loop slides off the nose plate 18 and is thus clearly ejected from the machine.

During the sequence described above, as the gripper 15 opens the bellcrank lever 35 tends to move angularly in a counterclockwise direction under the influence of the tension spring 38 to return the guide block 30 to the operative position. This tendency is prevented by the cooperation with the slot 45 in the nose plate of the pin 44 in the block 30, as otherwise it would be possible for the guide block 30 to return to its inoperative position and damage either the vibratory block or itself.

After the sealed loop of tape has been ejected from the machine and the vibratory block 26 retracted the nose plate 18 is returned to its operative position by operation of the pneumatic cylinder NP, and the guide block 30 is then returned to its operative position as illustrated due to the action of the tension spring 38.

We claim:

1. A package binding machine comprising a support, a nose plate carried from said support and having opposed faces, sealing means for joining together overlapping ends of a loop of binding tape by friction welding on said nose plate, means for moving said nose plate with respect to said support between an operative position, in which one of said faces is adapted to provide a support for overlapping ends of a loop of binding tape, and a retracted position, in which there is defined between said nose plate and said support a clearance through which a sealed joint of binding tape can be ejected from the machine, and means for moving said sealing means towards and away from said one face of said nose plate when in said operative position to join together overlapping ends of a loop of binding tape supported on said one face of said nose plate.

2. A package binding machine as claimed in claim 1, including a mounting, a connection between said mounting and said nose plate, a pivotal connection between said mounting and said support, and actuating means for moving said mounting angularly about said pivotal connection to swing said nose plate between said operative and retracted positions.

3. A package binding machine as claimed in claim 2, wherein said mounting comprises a pair of spaced parallel levers having inner and outer opposite ends, a pivotal connection between said outer ends of said levers and said nose plate, and a coupling between said inner ends of said levers and said actuating means, and wherein said pivotal connection between said mounting and said frame is located at aligned points intermediate opposite ends of each lever.

4. A packing binding machine as claimed in claim 2, wherein said actuating means comprises a pneumatic actuator including a piston rod, and a trunnion connected to said piston rod provides said coupling between said inner ends of said levers.

5. A package binding machine as claimed in claim 1, incorporating an abutment fixed relative to said support, wherein said abutment and said nose plate have an operative engagement when said nose plate is in said operative position whereby said nose plate is supported against pressure exerted thereon by said sealing means.

6. A package binding machine comprising a support. a nose plate carried from said support and having opposed faces. sealing means for joining together overlapping ends of a loop of binding tape by friction welding on said nose plate. means for moving said plate with respect to said support between an operative position. in which one of said faces is adapted to provide a support for overlapping ends of a loop of binding tape. and a retracted position, in which there is defined between said nose plate and said support a clearance through which a sealed joint of binding tape can be ejected from the machine, and means for moving said sealing means towards and away from said one face of said nose plate when in said operative position to join together overlapping ends of a loop of binding tape supported on said one face of said nose plate, a guide carried from said support, means for moving said guide between an operative position with respect to said one face of said nose plate, when said nose plate is in its operative position, and a retracted position in which overlapping tape ends adapted to be supported on said one face of said nose plate are exposed to said sealing means, and means in said guide defining a continuous guide path for tape through said nose plate when said guide is in said operative position and at least until end portions of the tape have been brought into an overlapping relationship.

7. A package binding machine as claimed in claim 6, including a lost-motion connection providing a coupling between said guide and said nose plate, said lost motion connection incorporating means permitting independent limited movement of said guide relative to said nose plate between its operative and retracted positions when said nose plate is in its operative position, and means for holding said guide in its retracted position when said nose plate is moved into its retracted position.

8. A package binding machine as claimed in claim 7, wherein said lost-motion coupling comprise a pin carried by said guide working in an elongated slot in said nose plate.

9. A package binding machine as claimed in claim 6, wherein said guide comprises a block having a lower face, and there is an operative engagement between said lower face and said one face of said nose plate when said block and said nose plate are in their operative positions, the said block being fonned between opposite ends with a slot through which tape from a supply is adapted to be guided through said block, and said lower face of said block is provided with a relief in which the free end of a loop of tape is adapted to be received after said free end has been passed around a package.

10. A package binding machine as claimed in claim 9, wherein said relief has an innermost end which terminates in a vertical stop face to form a dead stop for the free end of the tape.

11. A package binding machine comprising a support, a nose plate carried from said support and having opposed faces, sealing means for joining together overlapping ends of a loop of binding tape by friction welding on said nose plate, means for moving said nose plate with respect to said support between an operative position, in which one of said faces is adapted to provide a support for overlapping ends of a loop of binding tape, and a retracted position, in which there is defined between said nose plate and said support a clearance through which a sealed joint of binding tape can be ejected from the machine, means for moving said sealing means towards and away from said one face of said nose plate when in said operative position to join together overlapping ends of a loop of binding tape supported on said one face of said nose plate, first and second spaced grippers for engagement with said one face of said nose plate when said nose plate is in the operative position, first actuating means normally holding said first gripper in a retracted position spaced from said nose plate but operative to urge said first gripper towards said nose plate to gripltherebetween the tape adjacent to its free end, second actuating means normally holding said second gripper in a retracted position spaced from said nose plate but operative, after operation of said first actuating means, to urge said gripper towards said nose plate to grip therebetween the tape at a position spaced outwardly from its free end. and said first gripper is provided with a first aperture through which the free end of the tape is passed through a clearance defined between said nose plate and said second gripper when said second gripper is in its retracted position whereby the tape is gripped to said nose plate at two spaced positions and the overlapping ends of the tape are freed from tension.

12. A package binding machine as claimed in claim 11, wherein said first and second actuating means each comprises a lever having first and second opposite ends. a pivotal connection between said first end of said lever and said support, a pivotal connection between a point in said lever intermediate said opposite ends and one respective gripper. a pneumatic cylinder and a pivotal connection between said pneumatic cylinder and said second end of said lever.

B. A package binding machine as claimed in claim 11, including a guide block movable between an operative position with respect to said one face of said nose plate, when said nose plate is in its operative position, and a retracted position in which overlapping tape ends adapted to be supported on said nose plate are exposed to said sealing means, said guide block defining in its operative position a continuous guide path for tape through said nose plate until the end of the tape have been brought into an overlapping relationship, a bellcrank lever having first and second opposed arms, a pivotal connection between said support and a part of said lever intermediate adjacent ends of said arms, a pivotal connection between said first arm and said guide block, resilient means acting on said second arm to urge said block towards its operative position, and a lost-motion connection providing a coupling between said first gripper and said second arm, said lost-motion connection being so constructed and arranged that said guide block is moved into its retracted position as said first gripper is moved towards said nose plate.

14. A package binding machine as claimed in claim 13, wherein said lost-motion connection comprises a pin carried by said second arm of said bellcrank lever engaging in a second aperture in said first gripper spaced above said first aperture.

15. A package binding machine as claimed in claim 11, incorporating cutting means to sever the tape from the supply, said cutting means operating in synchronism with said second gripper to grip the tape against said nose plate and movement of said sealing means towards said nose plate.

16. A package binding machine as claimed in claim 11, wherein said sealing means comprises a block, including resilient means for urging said block into engagement with the overlapping tape ends supported on said nose plate and means for vibrating said block at high frequency relative to said nose plate.

17. A package binding machine as claimed in claim 16, wherein said block vibrating means comprise an electric motor and an eccentric drive between said motor and said block.

18. A package binding machine comprising a base plate having an aperture in a free edge thereof, a frame fixedly mounted on said base plate, a nose plate an innermost edge on said nose plate, a first pair of levers having first and second aligned opposite ends, a pivotal connection between said nose plate and said first end of each lever, a pivotal connection between said frame and each lever intermediate opposite ends thereof, actuating means acting on said second end of each lever to move said nose :plate between an operative position and a retracted position, in said operative position, said nose plate is, at least at said innermost edge thereof, received in said aperture in said base plate to provide a support for overlapping ends of a loop of binding tape, and in said retracted position at least said innermost edge of said nose plate is spaced from said aperture and there is defined between said innermost edge of said nose plate and an adjacent part of said base plate a clearance through which a sealed joint of binding material can be ejected from the machine, abutment means on each of said levers-defining a limiting position for said nose plate in said retracted position resilient means normally urging said nose plate in a direction towards said abutments on said levers about said pivotal connections between said nose plate and said levers. sealing means for joining together overlapping tape ends by friction welding on said nose plate, said sealing means being mounted for movement towards and away from said nose plate in a guideway in said frame, means for moving said sealing means towards and away from said nose plate, when in its operative position, and a step in the innermost edge of said aperture in said base plate providing an abutment with which engages said innermost edge of said nose plate to support said nose plate against pressure exerted thereon by said sealing means when said nose plate is in said operative position.

19 A package binding machine as claimed in claim 18, including first and second spaced grippers for engagement with said nose plate when said nose plate is in its operative position,

a second pair of levers having first and second opposite ends, a pivotal connection between said first end of each lever and said frame, a pivotal connection between the second end of each lever and an actuator movable between an extended and a contracted position, a pivotal connection between each lever at a point in its length intermediate said first and second ends thereof and a respective one of said first and second grippers, each of said actuators in its contracted position holding its respective gripper in a retracted position spaced from said nose plate and, when each actuator is extended, its respective gripper is urged towards said nose plate to grip therebetween the overlapping tape ends support on said nose plate, and said first gripper is provided with an aperture through which the free end of the tape is passed before it is passed through a clearance defined between said nose plate and said second gripper when said second gripper is in its retracted position.

Claims

6. A package binding machine comprising a support, a nose plate carried from said support and having opposed faces, sealing means for joining together overlapping ends of a loop of binding tape by friction welding on said nose plate, means for moving said plate with respect to said support between an operative position, in which one of said faces is adapted to provide a support for overlapping ends of a loop of binding tape, and a retracted position, in which there is defined between said nose plate and said support a clearance through which a sealed joint of binding tape can be ejected from the machine, and means for moving said sealing means towards and away from said one face of said nose plate when in said operative position to join together overlapping ends of a loop of binding tape supported on said one face of said nose plate, a guide carried from said support, means for moving said guide between an operative position with respect to said one face of said nose plate, when said nose plate is in its operative position, and a retracted position in which overlapping tape ends adapted to be supported on said one face of said nose plate are exposed to said sealing means, and means in said guide defining a continuous guide path for tape through said nose plate when said guide is in said operative position and at least until end portions of the tape have been brought into an overlapping relationship.

7. A package binding machine as claimed in claim 6, including a lost-motion connection providing a coupling between said guide and said nose plate, said lost-motion connection incorporating means permitting independent limited movement of said guide relative to said nose plate between its operative and retracted positions when said nose plate is in its operative position, and means for holding said guide in its retracted position when said nose plate is moved into its retracted position.

9. A package binding machine as claimed in claim 6, wherein said guide comprises a block having a lower face, and there is an operative engagement between said lower face and said one face of said nose plate when said block and said nose plate are in their operative positions, the said block being formed between opposite ends with a slot through which tape from a supply is adapted to be guided through said block, and said lower face of said block is provided with a relief in which the free end of a loop of tape is adapted to be received after said free end has been passed around a package.

11. A package binding machine comprising a support, a nose plate carried from said support and having opposed faces, sealing means for joining together overlapping ends of a loop of binding tape by friction welding on said nose plate, means for moving said nose plate with respect to said support between an operative position, in which one of said faces is adapted to provide a support for overlapping ends of a loop of binding tape, and a retracted position, in which there is defined between said nose plate and said support a clearance through which a sealed joint of binding tape can be ejected from the machine, means for moving said sealing means towards and away from said one face of said nose plate when in said operative position to join together overlapping ends of a loop of binding tape supported on said one face of said nose plate, first and second spaced grippers for engagement with said one face of said nose plate when said nose plate is in the operative position, first actuating means normally holding said first gripper in a retracted position spaced from said nose plate but operative to urge said first gripper towards said nose plate to grip therebetween the tape adjacent to its free end, second actuating means normally holding said second gripper in a retracted position spaced from said nose plate but operative, after operation of said first actuating means, to urge said gripper towards said nose plate to grip therebetween the tape at a position spaced outwardly from its free end, and said first gripper is provided with a first aperture through which the free end of the tape is passed through a clearance defined between said nose plate and said second gripper when said second gripper is in its retracted position whereby the tape is gripped to said nose plate at two spaced positions and the overlapping ends of the tape are freed from tension.

12. A package binding machine as claimed in claim 11, wherein said first and second actuating means each comprises a lever having first and second opposite ends, a pivotal connection between said first end of said lever and said support, a pivotal connection between a point in said lever intermediate said opposite ends and one respective gripper, a pneumatic cylinder and a pivotal connection between said pneumatic cylinder and said second end of said lever.

13. A package binding machine as claimed in claim 11, including a guide block movable between an operative position with respect to said one face of said nose plate, when said nose plate is in its operative position, and a retracted position in which overlapping tape ends adapted to be supported on said nose plate are exposed to said sealing means, said guide block defining in its operative position a continuous guide path for tape through said nose plate until the end of the tape have been brought into an overlapping relationship, a bellcrank lever having first and second opposed arms, a pivotal connection between said support and a part of said lever intermediate adjacent ends of said arms, a pivotal connection between said first arm and said guide block, resilieNt means acting on said second arm to urge said block towards its operative position, and a lost-motion connection providing a coupling between said first gripper and said second arm, said lost-motion connection being so constructed and arranged that said guide block is moved into its retracted position as said first gripper is moved towards said nose plate.

18. A package binding machine comprising a base plate having an aperture in a free edge thereof, a frame fixedly mounted on said base plate, a nose plate an innermost edge on said nose plate, a first pair of levers having first and second aligned opposite ends, a pivotal connection between said nose plate and said first end of each lever, a pivotal connection between said frame and each lever intermediate opposite ends thereof, actuating means acting on said second end of each lever to move said nose plate between an operative position and a retracted position, in said operative position, said nose plate is, at least at said innermost edge thereof, received in said aperture in said base plate to provide a support for overlapping ends of a loop of binding tape, and in said retracted position at least said innermost edge of said nose plate is spaced from said aperture and there is defined between said innermost edge of said nose plate and an adjacent part of said base plate a clearance through which a sealed joint of binding material can be ejected from the machine, abutment means on each of said levers defining a limiting position for said nose plate in said retracted position, resilient means normally urging said nose plate in a direction towards said abutments on said levers about said pivotal connections between said nose plate and said levers, sealing means for joining together overlapping tape ends by friction welding on said nose plate, said sealing means being mounted for movement towards and away from said nose plate in a guideway in said frame, means for moving said sealing means towards and away from said nose plate, when in its operative position, and a step in the innermost edge of said aperture in said base plate providing an abutment with which engages said innermost edge of said nose plate to support said nose plate against pressure exerted thereon by said sealing means when said nose plate is in said operative position. 19 A package binding machine as claimed in claim 18, including first and second spaced grippers for engagement with said nose plate when said nose plate is in its operative position, a second pair of levers having first and second opposite ends, a pivotal connection between said first end of each lever and said frame, a pivotal connection between the second end of each lever and an actuator movable between an extended and a contracted position, a pivotal connection between each lever at a point in its length intermediate said first and second ends thereof and a respective one of said first and second grippers, each of said actuators in its contracted position holding its respective Gripper in a retracted position spaced from said nose plate and, when each actuator is extended, its respective gripper is urged towards said nose plate to grip therebetween the overlapping tape ends support on said nose plate, and said first gripper is provided with an aperture through which the free end of the tape is passed before it is passed through a clearance defined between said nose plate and said second gripper when said second gripper is in its retracted position.