Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B13/00—Bundling articles
  • B65B13/18—Details of, or auxiliary devices used in, bundling machines or bundling tools
  • B65B13/24—Securing ends of binding material
  • B65B13/32—Securing ends of binding material by welding, soldering, or heat-sealing; by applying adhesive
  • B65B13/327—Hand tools

Definitions

• the invention relates to a device for strapping an object with a thereat-weldable plastic band, according to the preamble of claim 1.
• a strapping device of the type mentioned is known for example from US-3269300 and comprises a device for tensioning the band and a device for friction welding two overlapping band parts of the tensioned band between two welding jaws.
• Each of these devices is assigned a motor, a switch for controlling this motor via a control circuit and a cam for actuating the switch.
• the two cams can be rotated together about a common axis of rotation.
• One of the welding jaws can be displaced essentially orthogonally to the axis of rotation and can be adjusted by means of a cam mechanism.
• the cam mechanism comprises a cam disc which can be rotated about the axis of rotation together with one of the cams, and a telescopic plunger which is functionally arranged between the cam disc and the displaceable welding jaw and which can be telescopically extended and retracted substantially orthogonally to the axis of rotation and spring-loaded to extend it .
• a disadvantage of this known strapping tool is that the pressure of the welding jaws on the plastic straps depends on their thickness. If the pressing force is too high, the motors are required to perform too high, the motor speed drops and the strapping tool no longer works properly. Nevertheless, in this known strapping device, no possibility of adaptation to the use of plastic strips of different thickness is provided.
• the stated task is carried out at a Strapping tool of the type mentioned solved by the characterizing features of claim 1.
• the maximum force with which the welding jaws are stressed relative to one another is determined by the relative rotational position of the cam plate at least to one of the cams, especially since this maximum force occurs at an extreme rotational or angular position of the cam plate, which thereby it is given that at least one of the cams can be rotated to a limited extent relative to the device when it rotates about the axis of rotation.
• this maximum force can be adjusted via the setting of the relative rotational position between the cam and the cams mentioned and can therefore be selected as a function of the thickness of the plastic straps, so that the strapping device can be used with plastic straps of different thicknesses.
• plastic straps from 0.4 mm to 1.05 mm thick can be used, the pressing force of the welding jaws on the plastic straps being able to be adjusted almost constantly, so that the strapping device always works correctly regardless of the thickness of the plastic straps.
• one of the cams can be assigned a stop lug to limit its rotation about the axis of rotation in cooperation with a stop fixedly arranged on the device, which determines the extreme rotational or angular position of the cam disk, which in turn determines the maximum stressing force of the welding jaws to one another.
• the cams are each arranged on an associated shaft part.
• the axis of rotation is common to the two shaft parts.
• the two shaft parts can be separated from one another between the two cams or can be connected to one another in a rotationally fixed manner by mutual toothing.
• This toothing is a longitudinal toothing with surface lines lying parallel to the axis of rotation educated.
• the two shaft parts one is designed in the form of a pin in the vicinity of an end part thereof and provided with external teeth, the other in the vicinity of an end part thereof is designed as a sleeve part provided with internal teeth.
• the two shaft parts can be inserted coaxially into one another in the region of their peg-shaped or sleeve-shaped end part, displaceable relative to one another and detachable from one another.
• the cam disk which is designed as an eccentric cylinder, is arranged on a shaft part which is rotatable and axially held on the device, while the other shaft part is arranged on the device in a rotatable and axially displaceable manner.
• the axially displaceable shaft part is supported by a spring element on a housing part fixedly arranged on the device, is arranged so as to protrude from the housing part and is stressed by the spring element towards the axially fixed shaft part.
• the axially displaceable shaft part can be pulled out by hand on the housing part using a knob and then rotated; when released, the pulled-out shaft part tends to interlock again with the other shaft part;
• the relative rotational position of the stop lug and the cam disc and thereby the extreme rotational or angular position of the cam disc and the maximum stressing force of the welding jaws relative to one another are determined from the relative rotational position of the shaft parts thus achieved; In this way, this stress can be adjusted to adapt to the thickness of the plastic strips.
• the one longitudinal toothing has a tooth bridge area in which several teeth, viewed in cross-section, are fused from tip to tip, whereby this longitudinal toothing has a filling.
• the other longitudinal toothing has a tooth space area in which several teeth, viewed in cross-section, are left out from root to root, with which this longitudinal toothing has a recess.
• the dental bridge area extends over a smaller number of teeth and thus with respect the axis of rotation over a smaller angle than the tooth gap area.
• FIG. 1 shows an exploded perspective view of parts of a strapping device to illustrate the strapping device according to the invention in an end position thereof;
• FIG. 2 shows a further perspective exploded view of the parts of the strapping device according to FIG. 1, shown in a different viewing direction;
• FIG. 3 shows a perspective view of the parts of the strapping device according to FIG. 1 which are assembled to one another;
• FIG. 4 shows an exploded perspective view of two special parts of the strapping device according to FIG. 1, to illustrate a mutual longitudinal toothing of these parts;
• FIG. 5 shows an exploded perspective view of parts of a strapping device to illustrate the strapping device according to the invention in a specific starting position thereof;
• FIG. 6 shows a further perspective exploded view of the parts of the strapping device according to FIG. 5, shown in a different viewing direction;
• FIG. 7 shows a perspective view of the parts of the strapping device according to FIG. 5 which are assembled to one another;
• FIG. 8 shows an exploded perspective view of parts of a strapping device as in FIG. 5, but with the strapping device according to the invention in a different starting position;
• FIG. 9 shows a further perspective exploded view of the parts of the strapping device according to FIG. 8, shown in a different viewing direction;
• FIG. 10 shows a perspective view of the parts of the strapping device according to FIG. 8 which are assembled to one another;
• FIG. 11 shows a side view of parts of a strapping device in the same starting position as in FIGS. 5, 6 and 7 to illustrate the cams and switches in particular and their interaction;
• FIG. 12 shows a side view of parts of a strapping device in the same starting position as in FIGS. 8, 9 and 10 to particularly illustrate the cams and switches and their interaction;
• FIG. 13 shows a side view of the shafts according to the invention of a strapping device in the same end position of the shafts as in FIGS. 1, 2 and 3, and a view of housing parts of the strapping device in section through an axis of rotation of the shafts and a displacement direction of welding jaws of the strapping device;
• FIG. 14 shows a perspective view of the parts of the strapping device according to FIG. 1 which are assembled to one another, but with the strapping device according to the invention in a different end position.
• a generic strapping tool is used for strapping an object with a thermoweldable plastic band around it, from which a loop is formed around the object and then tensioned. When the tape reaches a suitable tension, it is sealed by strapping it by thermal welding overlapping ends thereof.
• the strapping device is provided with a device for tensioning the plastic band, which is driven by a tensioning motor.
• a tensioning motor Such a device is known per se, for example from document US-3269300 cited at the outset, and is not described in more detail here, because the control of the motor of this device is important in the design of the strapping device described here.
• the strapping tool is also provided with a device for friction welding two overlapping strap parts of the tensioned strap between two welding jaws, which is driven by a friction welding motor.
• a device for friction welding two overlapping strap parts of the tensioned strap between two welding jaws which is driven by a friction welding motor.
• the principle of such a device is known per se, for example from document US-3269300 cited at the beginning.
• Fig. 2 the tensioned plastic band 1 and the latter welding jaws 2 and 3 are shown (Fig. 2, 6, 9, 13). 13 shows in cross section the shaft 51 of the friction welding motor which reciprocates the welding jaw 2 via an eccentric bearing 52 and a connecting rod 53 relative to the other welding jaw 3, which is fixedly arranged on a housing part 54 of the strapping device, during the friction welding drives.
• the two motors mentioned are controlled by an assigned switch via an assigned control circuit.
• These motors can be designed as electrical, but also as pneumatic motors, and depending on them, an electrical, electropneumatic or pneumatic control circuit is assigned to them.
• an electrical, electropneumatic or pneumatic control circuit is assigned to them.
• a control block 55 (FIG. 13), which contains the two switches and electronic control circuits for the motors, is arranged on the housing part 54 of the strapping device (the two switches 4 and 5 are not visible in FIGS. 4 and 13; in FIGS. 11 and 12 the two switches are exactly one behind the other, switch 4 hides switch 5),
• the switches 4 and 5 are each provided with a switch lever 24 or 25, which in turn has a scanning roller 34 or 35 (designated in Fig. 6, 7, 11, 12), via which the switches 4 and 5 by each an assigned cam 6 or 7 can be controlled.
• the two cams 6 and 7 are rotatable independently of one another about a common axis of rotation 8, and they can interact by a stop lug 26 of the cam 6 (designated in FIGS. 1, 2, 3, 4, 11, 12, 14) with a Stop 27 (designated in Fig. 1, 2, 3, 7, 11, 12, 14) can come into contact.
• the tensioning motor is controlled by the cam 7, which is seated on a sleeve part 9 (FIGS. 1, 3, 10, 13) of the housing part 54 so as to be rotatable about the axis of rotation 8.
• the cam 7 has an actuating lever 57, the root part 62 (FIG. 2) acting as a stop lug can come into contact with a stop 63 (FIG. 1) of the housing part 54, which limits the rotation of the cam 7.
• the actuating lever 57 is urged toward the stop 63 by a spring 65 (FIGS. 1, 5, 8) guided in a guide tube 64.
• a control shaft 10 is rotatably mounted on the housing part 54 on the axis of rotation 8, coaxial to the sleeve part 9.
• An actuating lever 16 is arranged at one end of the control shaft 10. In the vicinity of the other, pin-shaped end part 11 of the control shaft 10, the latter is provided with a toothing 12 which releasably fits a toothing 36 (FIGS. 1, 4, 6) of the cam 6, which allows the cam 6 to rotate on the pin-shaped end part 11 to set the control shaft 10 (Fig. 3, 7, 10, 13, 14) or to remove it. If the cam 6 is placed on the control shaft 10, the user can set and change the rotational position of the cam 6 via the actuating lever 16 and thereby start the friction welding, as will be described below.
• the welding jaw 2 (i.e. the one of the two welding jaws 2 and 3 closest to the control shaft 10) can be displaced relative to the housing part 54 essentially orthogonally to the axis of rotation 8 (FIG. 13).
• the distance between the welding jaw 2 and the axis of rotation 8 is determined by the position of the other welding jaw 3 and the thickness of the plastic strip 1 lying between them.
• the force with which the welding jaws 2 and 3 are stressed against one another and press the plastic strip 1 together can be adjusted by means of a cam mechanism 13:
• This cam mechanism 13 comprises, as a cam disk 14, an eccentric cylinder formed on the control shaft 10 (more clearly visible in FIGS.
• the retractable and extendable telescopic plunger 15 comprises two telescopically displaceable plunger parts 19 and 20 and in between a compression spring element 21 which acts on the telescopic plunger 15 to extend it.
• a sliding sleeve 22 is also arranged between the cam disk 14 and the tappet part 19.
• a pressure piece 23 and a ball or roller bearing 28 are also arranged between the welding jaw 2 and the plunger part 20, the force of the compression spring 21 being transmitted orthogonally to the axis of rotation 8 from the plunger part 20 onto the pressure piece 23 and balls or rollers 29 of the bearing 28 further transmit this force to the welding jaw 2.
• the two welding jaws 2 and 3 pressed together and, if necessary, the plastic strip 1 in between is pressed together.
• the force with which the welding jaws 2 and 3 are stressed against each other and press the plastic band 1 together is determined by the effective length of the telescopic plunger 15 or the relative position of the plunger parts 19 and 20, which position in turn depends on the rotational position of the cam plate 14 and consequently depends on the rotational position of the control shaft 10 in the relevant end positions.
• the parts of the cam mechanism 13 are arranged in a direction substantially orthogonal to the axis of rotation 8 (in a manner not shown), and the extension of the telescopic plunger 15 is (in a manner not shown) by a system of cross pin and Longitudinal slot limited, which allows the telescopic plunger 15 with a corresponding rotational position of the control shaft 10 to lift the welding jaw 2 from the welding jaw 3 and remove it.
• the specified rotation of the control shaft 10 away from its end position is brought about by the user using the actuating lever 16.
• the control shaft 10 can be rotated to an initial position (FIGS. 5, 6, 7, 8, 9, 10) in which a stop lug 30 (FIGS. 5, 6, 8, 9) of the actuating lever 16 with a stop 31 (Fig. 6, 9) of the housing part 54 is in contact.
• this starting position the welding jaws 2 and 3 are fully lifted apart.
• a catch holds the actuating lever 16 in this starting position by providing resistance against unwanted twisting: this catch consists of a hollow spherical recess 37 (FIGS. 1, 5, 8) provided in the actuating lever 16 in interaction with a ball 38 (FIG. 5 , 6, 8, 9) which are acted upon by a spring 39 towards the recess 37. is struck, the spring 39 and at least partially the ball 38 are arranged in a receiving bore 40 (Fig. 2, 6, 9) of the housing part 54.
• the relative rotational position of the cam disk 14 and the cam 6 can therefore be adjusted in the manner described below via the relative rotational position with which the cam 6 is placed on the control shaft 10.
• the cam 6 is provided with a sleeve part 41 (FIGS. 5, 8) which is internally formed with the toothing 36 and is cylindrical on the outside. With its cylindrical outer side, the sleeve part 41 is arranged in a cylindrical receiving sleeve 42 at the end of an auxiliary shaft 32 and fastened to it with the aid of a clamping sleeve 33 (FIGS. 4, 6). If the cam 6 with its toothing 36 is placed on the toothing 12 of the control shaft 10 and therefore non-rotatably on the end 11 of the control shaft 10 (FIGS. 3, 7, 10, 13, 14), the auxiliary shaft 32 lies coaxially with the control shaft 10 their extension on the axis of rotation 8.
• the auxiliary shaft 32 is axially displaceably supported in a bearing 43 (FIG. 13) of a further housing part 44 fixedly arranged on the housing part 54.
• An end region 46 of the auxiliary shaft 32 protrudes from the housing part 44 and is provided with a knob 45 at its free end.
• a spring 56 (FIG. 13) is arranged on the auxiliary shaft 32 between the receiving sleeve 42 and the housing part 44 and acts on the receiving sleeve 42 towards the control shaft 10. Against the force of this spring 56, the auxiliary shaft 32 can be pulled axially away from the control shaft 10 by hand and with the aid of a knob 45 arranged at the free end of the auxiliary shaft 32, which releases the mutual engagement of the toothings 12 and 36 and thereby the cam 6 from the Control shaft 10 pulls away and removed.
• the toothings 12 and 36 come back into engagement with one another in accordance with the relative rotational position of the cam 6 and the end 11 of the control shaft 10, ie also in accordance with the relative rotational position of the auxiliary shaft 32 and the control shaft 10.
• the toothing 12 ends just before the end 11 of the control shaft 10 and this end 11 itself is designed as a pin of smaller diameter.
• the two cams 6 and 7 are each arranged on an associated shaft part (namely on the control shaft 10 and the auxiliary shaft 32); These two shaft parts have a common axis of rotation 8 and can be separated from one another or non-rotatably connected between the two cams 6 and 7 by means of mutual toothing;
• One shaft part, namely the control shaft 10 is rotatable and axially held on the device and supports the cam disk 14.
• the other shaft part 32 is rotatably and axially displaceable on the device;
• the axially displaceable shaft part (32) is supported by a spring element (56) on a housing part (44) fixedly arranged on the device, arranged protruding from the housing part (44) and stressed by the spring element (56) towards the axially fixed shaft part (10).
• the toothings 12 and 36 are designed as longitudinal toothings with surface lines 49 and 50 lying parallel to the axis of rotation 8 (FIG. 4).
• the longitudinal toothing 12 is an external toothing in the vicinity of the pin-shaped end part 11 of the control shaft 10.
• the longitudinal toothing 36 is an internal toothing in the sleeve part 41 of the cam 6, which in turn lies in the receiving sleeve 42 at the end of the auxiliary shaft 32, so that the longitudinal toothing 36 is arranged in the vicinity of an end part of the auxiliary shaft 32.
• the two longitudinal toothings 12 and 36 can be inserted coaxially into one another, displaceable relative to one another and detachable from one another.
• the shaft parts 10 and 32 are placed on one another in impermissible relative rotational positions prevents the manner described below.
• the longitudinal toothing 36 of the auxiliary shaft 32 has a tooth bridge region 58, in which a plurality of teeth 60 of the longitudinal toothing 36, viewed in cross section, are fused from tip to tip, with which this longitudinal toothing 36 has, as it were, a filling in the region mentioned.
• the longitudinal toothing 12 of the control shaft 10 has a tooth space region 59, in which a plurality of teeth 61 of the longitudinal toothing 12, viewed in cross section, are omitted from root to root, with which this longitudinal toothing has a recess in the region mentioned.
• the two longitudinal toothings 12 and 36 therefore only fit one another in such relative rotational positions in which the tooth bridge area 58 or the filling can be inserted into the tooth space area 59 or into the recess.
• a permissible range of relative rotational positions of the shaft parts 10 and 32 is created in that the tooth bridge area 58 extends over a smaller number of teeth, i.e. extends over a smaller angular arc with respect to the axis of rotation 8 than the tooth space region 59, so that the tooth bridge region 58 can be introduced into the tooth space region 59 in a predetermined plurality of permissible rotational positions.
• the longitudinal toothings 12 and 36 can be interchanged in terms of their design with the tooth bridge area and tooth space area, i.e. the tooth space region 59 could be formed on the shaft part 32 and the tooth bridge region 58 on the shaft part 10.
• the longitudinal toothings of the shaft parts 10 and 32 would, if they did not have a tooth bridge area or tooth space area would be provided, each have 28 teeth, each of which extends over an arc of approximately 13 degrees.
• the tooth bridge area 58 on the shaft part 32 comprises two teeth (approximately 26 angular degrees) and the tooth gap region 59 on the shaft part 10 extends over six teeth (approximately 78 angular degrees). This results in five possible rotational positions in which the two longitudinal toothings 12 and 36 match one another and the tooth bridge area 58 can be inserted into the tooth space area 59 or the filling into the recess.
• the relative rotational position of the shaft parts 10 and 32 and consequently the cam disk 14 to the cam 6 can be adjusted over an angular arc range of approximately 64 angular degrees or approximately 18% of a revolution.
• the cam plate 14 is formed on the control shaft 10 as an eccentric cylinder offset by approximately 40% of its radius.
• the end position of the actuating lever 16 shown in FIG. 3 corresponds to a rotational position of the control shaft 10, in which the cam mechanism 13 is fully extended and the cam plate 14 is the spring-loaded most strongly for its extension toward its extension.
• the entire arrangement is dimensioned so that this rotational position provides the correct operating conditions for using the thinnest plastic tapes from the range provided, for example plastic tapes 0.4 mm thick.
• the end position of the actuating lever 16 shown in FIG. 14 corresponds to a rotational position of the control shaft 10, in which the cam mechanism 13 is approximately 64 angular degrees or approximately 18% of a revolution before the rotational position shown in FIG. 3.
• the cam disk 14 has been retracted by approximately 25% of its radius and the telescopic plunger 15 correspondingly less spring-loaded to extend it.
• the entire arrangement is dimensioned in such a way that this rotational position provides the correct operating conditions for using the thickest plastic tapes from the intended range, for example plastic tapes with a thickness of 1.05 mm.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Basic Packing Technique (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Orthopedics, Nursing, And Contraception (AREA)
• Surgical Instruments (AREA)

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Publications (2)

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• 1998
  • 1998-06-08 AT AT98922565T patent/ATE215464T1/de not_active IP Right Cessation
  • 1998-06-08 CA CA002297978A patent/CA2297978A1/fr not_active Abandoned
  • 1998-06-08 ES ES98922565T patent/ES2175710T3/es not_active Expired - Lifetime
  • 1998-06-08 WO PCT/CH1998/000245 patent/WO1999005025A1/fr active IP Right Grant
  • 1998-06-08 DE DE59803636T patent/DE59803636D1/de not_active Expired - Fee Related
  • 1998-06-08 EP EP98922565A patent/EP0998409B1/fr not_active Expired - Lifetime
  • 1998-06-18 US US09/463,288 patent/US6463847B1/en not_active Expired - Fee Related

Non-Patent Citations (1)

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