Strapping device with a linearly movable tensioning-and-sealing plate

Abstract

Various embodiments of the present disclosure provide a strapping device comprising a rotatable tensioning wheel, a linearly movable tensioning-and-sealing plate, a rotatable eccentric shaft operably connected to the tensioning-and-sealing plate such that rotation of the eccentric shaft causes the tensioning-and-sealing plate to linearly reciprocate relative to the tensioning wheel, and a motor operably connected to the eccentric shaft and configured to rotate the eccentric shaft.

Description

STRAPPING DEVICEWITH A LINEARLY MOVABLE TENSIONING- AND- SEALING PLATEPriority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 704,683, filed October 8, 2024, the entire contents of which is incorporated herein by reference.Field

[0002] The present disclosure relates to strapping devices, and more particularly to strapping devices configured to tension strap around a load and to attach overlapping layers of the strap to one another via friction welding to form a tensioned strap loop around the load.Background

[0003] Strapping devices are configured to tension strap around a load and to attach overlapping layers of the strap to one another to form a tensioned strap loop around the load. Handheld strapping tools, which can be electrically powered, pneumatically powered, or manually powered, are one common type of strapping device. Certain strapping tools, such as those configured for use with plastic or paper strap, use friction welding to attach overlapping upper and lower strap layers to one another.

[0004] To use one of these strapping tools to form a tensioned strap loop around a load, an operator pulls strap leading end first from a strap supply, wraps the strap around the load, and positions a lower layer of the strap including the leading end of the strap below an upper layer of the strap. The operator introduces the overlapped strap layers into the strapping tool so they extend between a toothed tensioning wheel and a toothed tensioning plate of the strapping tool and between a toothed weld shoe and a toothed weld plate of the strapping tool. The tensioning wheel and plate are typically positioned near the front of the strapping tool, while the weld shoe and plate are positioned rearward of and aligned with the tensioning wheel andplate. The tensioning wheel is spring biased to force the strap layers against the tensioning plate, while initially the weld shoe does not contact the strap.

[0005] The operator presses a button to initiate a tensioning cycle during which the tensioning wheel rotates to move the upper strap layer over the lower strap layer and tension the strap around the load. After completion of the tensioning cycle, a sealing cycle is initiated. During the sealing cycle, the weld shoe forces the strap layers against the weld plate. A motor reciprocates the weld shoe at a high frequency as the weld shoe exerts a welding force on the strap layers. The reciprocating weld shoe reciprocates the upper strap layer relative to the lower strap layer, which generates friction between portions of the overlapping strap layers that locally melts them. The motor stops reciprocating the weld shoe while the weld shoe continues to exert the welding force. The melted portions of the overlapping strap layers join and solidify as they cool, thereby attaching the upper and lower strap layers to form the tensioned strap loop.Summary

[0006] Various embodiments of the present disclosure provide a strapping device comprising a rotatable tensioning wheel, a linearly movable tensioning-and-sealing plate, a rotatable eccentric shaft operably connected to the tensioning-and-sealing plate such that rotation of the eccentric shaft causes the tensioning-and-sealing plate to linearly reciprocate relative to the tensioning wheel, and a motor operably connected to the eccentric shaft and configured to rotate the eccentric shaft.Brief Description of the Figures

[0007] Figure 1A is a perspective view of one example embodiment of a strapping tool of the present disclosure.

[0008] Figure IB is a block diagram of certain components of the strapping tool of Figure 1A.

[0009] Figures 2A-2C are diagrammatic views of the strapping tool of Figure 1 A securing a load to a pallet.

[0010] Figure 2D is a perspective view of a friction- weld strap joint formed by the strapping tool of Figure 1A.

[0011] Figures 3 A and 3B are perspective views of the working assembly of the strapping tool of Figure 1A.

[0012] Figures 4A and 4B are perspective and exploded perspective views, respectively, of the tensioning subassembly of the working assembly of Figures 3A and 3B.

[0013] Figure 4C is a cross-sectional perspective view of the tensioning subassembly of Figure 4A taken along line 4C-4C of Figure 4A.

[0014] Figure 5 is a perspective view of the sealing-and-cutting subassembly of the working assembly of Figures 3A and 3B.

[0015] Figures 6A and 6B are perspective and exploded perspective views, respectively, of the rocker subassembly of the sealing-and-cutting subassembly of Figure 5.

[0016] Figure 6C is a cross-sectional perspective view of the rocker subassembly of Figure 6A taken along line 6C-6C of Figure 6A.

[0017] Figures 7A and 7B are a perspective and exploded perspective views, respectively, of the cutter subassembly of the working assembly of Figures 3A and 3B.

[0018] Figures 8A, 8B, and 8C are perspective, front elevational, and side elevational views, respectively, of the eccentric shaft of the sealing-and-cutting subassembly of the working assembly of Figures 3 A and 3B.

[0019] Figures 9A-9D are side elevational views of the strapping tool of Figure 1A during a strapping process.

[0020] Figures 10A-10C are cross-sectional elevational views of the tensioning wheel and the tensioning-and-sealing plate of the working assembly of Figures 3 A and 3B and the upper and lower strap layers between those components during a sealing cycle of the strapping process. The cross-sectional views are taken along line 10A-10A of Figure 1A.

[0021] Figure 11 is a perspective view of the strapping tool of Figure 1 A showing part of the tensioning subassembly of Figure 4A and part of the sealing-and-cutting subassembly of Figure 5 after the strap cutter of the sealing-and-cutting subassembly has cut the upper strap layer from the strap supply.

[0022] Figures 12A and 12B are diagrammatical views of a prior art strapping tool and the strapping tool of Figure 1 A after strap has been applied to a substantially circular load.Detailed Description

[0023] While the systems, devices, and methods described herein may be embodied in various forms, the drawings show and the specification describes certain exemplary and nonlimiting embodiments. Not all the components shown in the drawings and described in the specification may be required, and certain implementations may include additional, different, or fewer components. Variations in the arrangement and type of the components; the shapes, sizes, and materials of the components; and the manners of connections of the components may be made without departing from the spirit or scope of the claims. Unless otherwise indicated, any directions referred to in the specification reflect the orientations of the components shown in the corresponding drawings and do not limit the scope of the present disclosure. Further, terms that refer to mounting methods, such as mounted, connected, etc., are not intended to be limited to direct mounting methods but should be interpreted broadly to include indirect and operably mounted, connected, and like mounting methods. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the present disclosure and as understood by one of ordinary skill in the art.

[0024] Figures 1 A-l 1 show one example embodiment of a strapping device of the present disclosure in the form of a battery-powered handheld strapping tool 50 and certain subassemblies and components thereof. As shown in Figures 2A-2C, the strapping tool 50 is configured to carry out a strapping process to tension and seal strap S (plastic strap in this example embodiment) around a load L on a pallet P to form a tensioned strap loop that secures the load L to the pallet P. An operator pulls strap S from a strap supply (not shown) and wraps the strap around the load L and through the openings in the pallet P until a lower strap layer LL of the strap S (which includes the leading end of the strap S) is positioned below an upper strap layer UL of the strap S, as shown in Figure 2A. The operator then introduces the overlapped upper and lower strap layers UL and LL of the strap S into the strapping tool 50 and actuates one or more buttons to initiate the strapping process. As shown in Figure 2B, the strapping tool 50 first carries out a tensioning cycle during which the strapping tool 50 tensions strap S around the load L. Once a preset tension is reached in the strap S, as shown in Figure 2C, the strapping tool 50 carries out a sealing cycle during which the strapping tool 50 connects the upper and lowerstrap layers UL and LL to one another via friction welding to form a strap joint SJ, as shown in Figure 2D, and cuts the strap S from the strap supply.

[0025] The strapping tool 50 includes a housing 100, a working assembly 150, a hand lever 1000, first and second pushbutton actuators 1410 and 1440, a power supply 1500, and a controller 1600.

[0026] The housing 100, which is shown in Figure 1A, is formed from multiple components that collectively at least partially enclose and / or support some or all the other subassemblies and components of the strapping tool 50. In this example embodiment, the housing 100 includes a front housing section that at least partially encloses the working assembly 150, a rear housing section that at least partially encloses and that supports the power supply 1500 and the controller 1600, and a handle extending between and connecting the front and rear housing sections. The handle is held by the operator during operation of the strapping device 50. The housing 100 may be formed from any suitable quantity of components joined together in any suitable manner. In this example embodiment, the housing 100 is formed from plastic, though it may be made from any other suitable material in other embodiments.

[0027] The working assembly 150, which is shown in Figures 3A-11, includes most of the components of the strapping tool 50 that are configured to carry out the strapping process to tension the strap around the load, to attach portions of overlapping upper and lower strap layers to one another to form a tensioned strap loop, and to cut the upper strap layer from the strap supply. The working assembly 150 includes a support 200, a tensioning subassembly 300, a sealing-and-cutting subassembly 400, a motor 800, and a transmission 900.

[0028] The support 200, which is best shown in Figures 3A and 3B, serves as a direct or indirect common support for at least some components of the tensioning subassembly 300, the sealing-and-cutting subassembly 400, the motor 800, the transmission 900, and the hand lever 1000. The support 200 includes a base 210, a first frame 220, and a second frame 230. The base 210 is substantially planar and substantially rectangular. The first frame 220 extends upward from the base 210 (from the perspective shown in Figures 3 A and 3B) and serves as a support for the tensioning subassembly 300, the sealing-and-cutting subassembly 400, and the hand lever 1000. The second frame 230 extends upward from the base 210 (from the perspective shown in Figures 3A and 3B) and serves as a support for the sealing-and-cutting subassembly400, the motor 800, and the transmission 900. This is one example configuration of the support, and other embodiments may be configured differently.

[0029] The tensioning subassembly 300, which is best shown in Figures 4A-4C, is configured to tension the strap around the load during the tensioning cycle. The tensioning subassembly 300 includes a driven shaft 310; a freewheel 320; a ring gear 330; a first set of planet gears 340a, 340b, and 340c; a first carrier 350; a second carrier 370; a rocker-subassembly mover 380; a second set of planet gears 390a, 390b, and 390c; a tensioning wheel 395; and a cover 300c. Certain components of the tensioning subassembly 300 are centered on, and certain components of the tensioning subassembly 300 are rotatable about, a tensioning axis A300.

[0030] The driven shaft 310 includes a cylindrical shaft portion 312 having a driven gear 314 (a bevel gear in this example embodiment) at one end and a first sun gear 316 at the end opposite the driven gear 314. The ring gear 330 includes an annular body 330 having inner teeth 330it arranged around the inner circumference of the body 332 and outer teeth 330ot arranged around the outer circumference of the body 332. The first carrier 350 includes a disc-shaped first planet-gear carrier 352, a cylindrical shaft portion 354 extending from the center of the first planet-gear carrier 352, and a second sun gear 356 at the end of the shaft portion 354. The first set of planet gears 340a, 340b, and 340c are rotatably mounted to the first planet-gear carrier 352 via suitable shafts. The second carrier 370 includes an annular mounting flange 372 and a second planet-gear carrier 374 longitudinally extending from the mounting flange 372. The second set of planet gears 390a, 390b, and 390c are mounted to the second planet-gear carrier 374 via suitable shafts. The tensioning wheel 395 includes an annular body having outer teeth 395ot around its outer circumference and inner teeth 395it around its inner circumference.

[0031] The driven shaft 310 is rotatably supported by a bearing 300bl press fit into the first frame 220 of the support 200 such that the driven shaft 310 can rotate relative to the support 200 about the tensioning axis A300. The shaft portion 312 of the driven shaft 310 extends through and is engaged by the freewheel 320. The freewheel 320 is supported by and positioned within a suitable bore defined through the first frame 220 of the support 200. The freewheel 320 is configured to permit rotation of the driven shaft 310 about the tensioning axis A300 in a tensioning rotational direction that results in rotation of the tensioning wheel 395 to tension the strap and to prevent rotation of the driven shaft 310 about the tensioning axis A300 in the opposite rotational direction. The first sun gear 316 of the driven shaft 310 meshes with the first set ofplanet gears 340a, 340b, and 340c. The first set of planet gears 340a, 340b, and 340c mesh with the inner teeth 33 Oit of the ring gear 330, which is rotatably supported by a bearing 300b2 press fit into the first frame 220 of the support 200 such that the ring gear 330 can rotate relative to the support 200 about the tensioning axis A300. The shaft portion 354 of the first carrier 350 extends through a bore defined through the second carrier 370. A bearing 300b3 press fit into that bore rotatably supports the shaft portion 354 such that the first carrier 350 is rotatable relative to the support 200 and the second carrier 370 about the tensioning axis A300. The rocker-subassembly mover 380 is rotatably mounted to the second planet-gear carrier 374 such that the rockersubassembly mover 380 can rotate relative to the second planet-gear carrier 374 about the tensioning axis A300. The mounting flange 372 of the second carrier 370 is fixedly mounted to the first frame 220 via suitable fasteners. The second sun gear 356 meshes with the second set of planet gears 390a, 390b, and 390c, which in turn mesh with the inner teeth 395it of the tensioning wheel 395. Bearings 300b4 and 300b5 rotatably support the tensioning wheel 395 on the second planet-gear carrier 374 of the second carrier 370 such that the tensioning wheel 395 is rotatable relative to the second carrier 370 about the tensioning axis A300. The cover 400c is attached to the second planet-gear carrier 374, such as via suitable fasteners, to retain certain of the components in place and protect the gearing.

[0032] In operation, rotation of the driven shaft 310 in the clockwise direction in the perspective shown in Figures 4A-4C results in rotation of the tensioning wheel 395 in the tensioning rotational direction, which is the counter-clockwise direction in the perspective shown in Figures 4A-4C. Specifically, rotation of the driven shaft 310 in the clockwise direction results in rotation of the first sun gear 316 in the clockwise direction. The first sun gear 316 drives the first set of planet gears 340a, 340b, and 340c to rotate about their respective shafts. Although not shown, a suitable lock — such as a clamping device or the decoupling assembly described in U.S. Patent No. 11,104,460 — engages the outer teeth 330ot of the ring gear 330 and prevents the ring gear 330 from rotating about the tensioning axis A300 during the tensioning and sealing cycles. Accordingly, the first set of planet gears 340a, 340b, and 340c rotate around the inner circumference of the ring gear 330 in the clockwise direction, causing the first carrier 350 — and the second sun gear 356 of the first carrier 350 — to rotate in the clockwise direction. The second sun gear 356 drives the second set of planet gears 380a, 380b, and 380c to rotate about their respective shafts. Since the second carrier 370 is fixed in rotation about the tensioning axis A300due to its fixed attachment to the first frame 220, the second set of planet gears 380a, 380b, and 380c drive the tensioning wheel 395 to rotate in the tensioning rotational direction (i.e., the counter-clockwise direction from the perspective shown in Figures 4A-4C).

[0033] The sealing-and-cutting subassembly 400, which is best shown in Figures 5- 8C, is configured to locally melt overlapping portions of the upper and lower strap layers via friction welding and to cut the upper strap layer from the strap supply during the sealing cycle. The sealing-and-cutting subassembly 400 includes a rocker subassembly 500, a cutter subassembly 600, and a drive subassembly 700.

[0034] The rocker subassembly 500, which is best shown in Figures 6A-6C, includes a rocker 510; bearings 520a, 520b, and 520c; a plate mount 530, a tensioning-and- sealing plate 540, a plate fastener 550, and a mount fastener 560. The rocker 510 includes a curved rocker arm 512 and a plate support 514. The rocker arm 512 has a first end 512a and a second end 512b, and the plate support 514 is attached to and in this example embodiment integrally formed with the second end 512b. The plate support 514 is substantially rectangular and has a mounting portion 514a, a support portion 514b opposite the mounting portion 514a, and an arm 516 between the mounting and support portions 514a and 514b. In this example embodiment, the bearings 520a and 520b are ball bearings and the bearings 520c are cylindrical bearings. The plate mount 530 includes a plate-mounting portion 532, a plate-mount driven portion 534, and a connecting portion 536 extending between and connecting the plate-mounting portion 532 and the plate-mount driven portion 534. The plate-mount driven portion 534 includes spaced-apart first and second arms 534a and 534b defining a cavity 534c therebetween. The tensioning-and-sealing plate 540 includes a body 542 having a toothed upper surface 542u and a substantially smooth lower surface 5421 opposite the upper surface 542u.

[0035] As best shown in Figure 6C, the tensioning-and-sealing plate 540 is fixedly mounted to the plate-mounting portion 532 of the plate mount 530 via the plate fastener 550 — which is a screw in this example embodiment — such that the lower surface 5421 abuts the platemounting portion 532. The plate mount 530 is slidably mounted to the plate support 514 via the bearings 520a, 520b, and 520c such that the plate mount 530 can linearly reciprocate relative to the plate support 514 in a transverse direction TD. The transverse direction TD corresponds to the width direction of the strap when inserted into the strapping tool and is substantially parallel to the tensioning axis A300. The transverse direction TD is substantially perpendicular to alongitudinal direction LD (Figure 1 A), which corresponds to the longitudinal direction of the strap when inserted into the strapping tool 50 and which is substantially perpendicular to the tensioning axis A300. Specifically, and as best shown in Figures 6A and 6C, the plate-mounting portion 532 of the plate mount 530 is positioned above the mounting portion 514a of the plate support 514. The bearings 520a and 520b are sandwiched between the lower surface of the platemounting portion 532 and the upper surface of the mounting portion 514, while the bearings 520c are sandwiched between opposing side surfaces of those components. The plate-mount driven portion 534 is positioned above the support portion 514b of the plate support 514. The mount fastener 560 is connected to the plate-mounting portion 532 of the plate mount 530 and extends through an elongated slot (best shown in Figure 6C) that is defined in the mounting portion 514a of the plate support 514 and that extends in the transverse direction TD. The extent of the linear reciprocation of the plate mount 530 is defined by the geometry of the eccentric shaft 710, which is described below, and the length of the slot through which the mount fastener 560 extends is sized accordingly to enable such reciprocation.

[0036] The rocker subassembly 500 is pivotably mounted to the first frame 220 of the support 200. Specifically, and as shown in Figure 3 A, the first end 512a of the rocker arm 512 of the rocker 510 is pivotably mounted to the first frame 220 via a shaft 500s. The rocker subassembly 500 is pivotable relative to the support 200, the tensioning subassembly 300, the cutter subassembly 600, and the drive subassembly 700 between a tensioning-and-sealing position shown in Figures 9B-9D and a strap-insertion position shown in Figure 9A. The tensioning-and-sealing plate 540 is adjacent to the tensioning wheel 395 when the rocker subassembly 500 is in the tensioning-and-sealing position and is further spaced from the tensioning wheel 395 when the rocker subassembly 500 is in the strap-insertion position. The hand lever 1000 is operably connected to the rocker subassembly 500 via the rockersubassembly mover 380 (and in certain embodiments one or more other linkages, gearing, or other components) such that actuation of the hand lever 1000 forces the rocker-subassembly mover 380 to rotate and in turn force the rocker subassembly 500 to pivot from the tensioning- and-sealing position to the strap-insertion position. A suitable biasing element, such as a compression spring, biases the rocker subassembly 500 to the tensioning-and-sealing position. In other embodiments, the motor is operably connected — via suitable gearing, linkages, and / or other components — to the rocker subassembly and configured to pivot the rocker subassemblyfrom the tensioning-and-sealing position to the strap-insertion position. In these embodiments, the strapping tool includes a suitable input device, such as the hand lever, a trigger, or a button, actuatable to cause the motor to pivot the rocker subassembly from the tensioning-and-sealing position to the strap-insertion position

[0037] The cutter subassembly 600, which is best shown in Figures 7A and 7B, includes a cutter support 610, a cutter mount 620, a strap cutter 630, and bearings 640a and 640b. The cutter support 610 includes a body 612 having a first end 612a, a second end 612b opposite the first end, and a central portion 612c between the first and second ends 612a and 612b. The cutter mount 620 includes a body 622 having a cutter-mount driven portion 622a at one end and a cutter-mounting portion 622b at the other end. The cutter-mount driven portion 622a defines a cavity 622al. In this example embodiment, the bearings 640a are cylindrical bearings and the bearings 640b are ball bearings. The strap cutter 630 includes multiple teeth 630t along one edge.

[0038] The strap cutter 630 is fixedly mounted to the cutter-mounting portion 622b of the cutter mount 620 via a fastener. The cutter mount 620 is slidably mounted to the cutter support 610 via the bearings 640a and 640b such that the cutter mount 620 — and the strap cutter 630 thereon — can linearly reciprocate relative to the cutter support 610 in the transverse direction TD. Specifically, part of the cutter-mounting portion 622b of the cutter mount 620 is received in a channel defined at the first end 612a of the body 612 of the cutter support 610. The bearings 640a and 640b are sandwiched between respective side surfaces of the body 612 and the cutter-mounting portion 622b.

[0039] The drive subassembly 700, which is best shown in Figures 5 and 8A-8C, includes an eccentric shaft 710, a driven gear pulley 720, a first bushing 730, and a second bushing 740. As best shown in Figures 8A-8C, the eccentric shaft 710 includes a first shaft portion 712, an eccentric portion 714, and a second shaft portion 716. The eccentric portion 714 is between the first and second shaft portions 712 and 716. The first and second shaft portions 712 and 716 are cylindrical and share the same central longitudinal shaft axis A710. The eccentric portion 714 is also cylindrical and has a central longitudinal eccentric axis A714 that is offset from and substantially parallel to the shaft axis A710. In other words, the eccentric portion 714 is radially offset from the shaft axis A710 such that rotation of the eccentric shaft 710 about the shaft axis A710 results in the eccentric axis A716 rotating about the shaft axis A710. The driven gear pulley 720, which is a gear pulley in this example embodiment, is fixed in rotation with the firstshaft portion 712 via a keyed mounting arrangement (though a splined or other suitable mounting arrangement may be used) such that the driven gear pulley 720 and the eccentric shaft 710 rotate together about the shaft axis A710. The first bushing 730 is annular and press fit around a first part of the eccentric portion 714, though in other embodiments the first bushing includes a needle bearing clearance fit around the first part of the eccentric portion. The second bushing 740 is annular and press fit around a second part of the eccentric portion 714, though in other embodiments the second bushing includes a needle bearing clearance fit around the second part of the eccentric portion.

[0040] As shown in Figures 3A and 3B, the support 200 rotatably supports the eccentric shaft 710. Specifically, the first shaft portion 712 is rotatably supported by a bearing press-fit into the second frame 230 of the support 200, and the second shaft portion 716 is rotatably supported by a bearing press-fit into the first frame 220 of the support 200 such that the eccentric shaft 710 is rotatable relative to those components about the shaft axis A710. The first and second bushings 730 and 740 operably connect the eccentric shaft 710 to the cutting mount 620 and the plate mount 530, respectively. Specifically, and as shown in Figure 5, the first bushing 730 is received in the cavity 622al defined in the cutter-mount driven portion 622a, and the second bushing 740 is received in the cavity 534c defined between the first and second arms 534a and 534b of the plate-mount driven portion 534 of the plate mount 530. As the eccentric shaft 710 rotates, the eccentricity of the eccentric portion 714 results in the plate mount 530 and the cutter mount 620 linearly reciprocating in the transverse direction TD. One complete rotation of the eccentric shaft 710 results in one complete back and forth linear movement of each of those components in this example embodiment. Additionally, in this example embodiment, part of the second bushing 740 (and therefore part of the eccentric portion 714) is within the cavity 534c regardless of the position of the rocker subassembly 500. In particular, a first portion of the second bushing 740 and the eccentric portion 714 is within the cavity 534c when the rocker subassembly 500 is in the tensioning-and-sealing position, and a second portion of the second bushing 740 and the eccentric portion 714 is within the cavity 534c when the rocker subassembly 500 is in the strap-insertion position. The second portion is smaller than the first portion.

[0041] The eccentric shaft 710 pivotably supports the cutter subassembly 600. Specifically, as shown in Figure 5, the second end 612b of the body 612 of the cutter support 610 is rotatably supported by a bearing supported by the first shaft portion 712 of the eccentric shaft710. The cutter subassembly 600 is pivotable about the shaft axis A710 downward from a rest position (Figures 3A and 9A-9C) to a cutting position (Figures 9D and 11).

[0042] The motor 800, which is shown in Figures IB, 3A, and 3B, is mounted to the second frame 230 and includes a rotatable output shaft 810. The motor 800 is configured to rotate the output shaft 810 in opposing first and second rotational directions RD1 and RD2 (indicated in Figure 3B) to carry out the tensioning and sealing cycles, respectively, as explained below. The motor 800 includes an electric motor in this example embodiment but may include any suitable motor or other actuator in other embodiments.

[0043] The transmission 900, which is best shown in Figures 3A and 3B, is driven by the motor 800 and is operably connected to: (1) the tensioning subassembly 300 and configured to cause the tensioning subassembly 300 to tension the strap around the load during the tensioning cycle by rotating the tensioning wheel 395 about the tensioning axis A300; and (2) the sealing-and-cutting subassembly 400 and configured to cause the sealing-and-cutting assembly 400 to locally melt the strap via friction welding during the sealing cycle by linearly reciprocating the tensioning-and-sealing plate 540 in the transverse direction TD relative to the tensioning wheel 395 and to cut the upper strap layer from the strap supply by linearly reciprocating the strap cutter 630 in the transverse direction TD. To do so, the transmission 900 is configured to: (1) transmit output from the motor 800 to the driven shaft 310 when the motor 800 rotates the output shaft 810 in the first rotational direction RD1; and (2) transmit output from the motor 800 to eccentric shaft 710 when the motor 800 rotates the output shaft 810 in the second rotational direction RD2. The transmission 900 includes a drive gear 910, a drive gear pulley 920, a connector 930, a cam 940, and a pivoter 950.

[0044] The drive gear 910, which is a bevel gear in this example embodiment, is mounted to the output shaft 810 via a first freewheel (not shown) and meshes with the driven gear 314 of the driven shaft 310. The first freewheel is configured to transmit rotational movement of the output shaft 810 in the first rotational direction RD1 to the drive gear 910 and not to transmit rotational movement of the output shaft 810 in the second rotational direction RD2 to the drive gear 910. Put differently, the drive gear 910 rotates with the output shaft 810 when the output shaft 810 rotates in the first rotational direction RD 1 but does not rotate with the output shaft 810 when the output shaft 810 rotates in the second rotational direction RD2.

[0045] The drive gear pulley 920 is mounted to the output shaft 810 via a second freewheel (not shown). The second freewheel is configured to transmit rotational movement of the output shaft 810 in the second rotational direction RD2 to the drive gear pulley 920 and not to transmit rotational movement of the output shaft 810 in the first rotational direction RD1 to the drive gear pulley 920. Put differently, the drive gear pulley 920 rotates with the output shaft 810 when the output shaft 810 rotates in the second rotational direction RD2 but does not rotate with the output shaft 810 when the output shaft 810 rotates in the first rotational direction RD1.

[0046] The connector 930, which is a toothed belt in this example embodiment, operably connects the drive gear pulley 920 to the driven gear pulley 720 of the drive subassembly 700 such that rotation of the drive gear pulley 920 results in rotation of the driven gear pulley 720 and, therefore, rotation of the eccentric shaft 710 fixed in rotation with the driven gear pulley 720.

[0047] The cam 940 is mounted to the output shaft 810 via a third freewheel (not shown). The third freewheel is configured to transmit rotational movement of the output shaft 810 in the second rotational direction RD2 to the cam 940 and not to transmit rotational movement of the output shaft 810 in the first rotational direction RD1 to the cam 940. Put differently, the cam 940 rotates with the output shaft 810 when the output shaft 810 rotates in the second rotational direction RD2 but does not rotate with the output shaft 810 when the output shaft 810 rotates in the first rotational direction RD1.

[0048] The pivoter 950 operably connects the cam 940 to the cutter subassembly 600 such that, when the cutter subassembly 600 is in the rest position, rotation of the cam 940 causes the cam 940 to actuate the pivoter 950 to force the cutter subassembly 600 to pivot to the cutting position. In this example embodiment, the pivoter 950 includes a toggle-lever device — such as that described in U.S. Patent No. 10,518,914 — though it may have any other configuration and include any other suitable components in other embodiments.

[0049] In operation, rotation of the output shaft 810 in the first rotational direction RD1 causes the drive gear 910 to drive the tensioning subassembly 300 to rotate the tensioning wheel 395. Rotation of the output shaft 820 in the second rotational direction RD2 causes: (1) the driven gear pulley 920 to (via the connector 930 and the driven gear pulley 720) drive the eccentric shaft 710 to rotate, causing the tensioning-and-sealing plate 540 and the strap cutter 630 to linearly reciprocate in the transverse direction TD; and (2) the cam 940 to (via the pivoter950) cause the cutter subassembly 600 to pivot to the cutting position. In this example embodiment, due to the geometry of the eccentric shaft the tensioning-and-sealing plate 540 and the strap cutter 630 linearly reciprocate in a substantially synchronous manner.

[0050] The controller 1600, which is shown in Figure IB, includes a processing device or devices communicatively connected to a memory device or devices. For instance, the controller may be a programmable logic controller. The processing device may include any suitable processing device such as, but not limited to, a general-purpose processor, a specialpurpose processor, a digital-signal processor, one or more microprocessors, one or more microprocessors in association with a digital-signal processor core, one or more applicationspecific integrated circuits, one or more field-programmable gate array circuits, one or more integrated circuits, and / or a state machine. The memory device may include any suitable memory device such as, but not limited to, read-only memory, random-access memory, one or more digital registers, cache memory, one or more semiconductor memory devices, magnetic media such as integrated hard disks and / or removable memory, magneto-optical media, and / or optical media. The memory device stores instructions executable by the processing device to control operation of the strapping tool 50. The controller 1600 is communicatively and operably connected to the motor 800. The controller 1600 may also be communicatively connectable (such as via Wi-Fi, Bluetooth, near-field communication, or other suitable wireless communications protocol) to an external device, such as a computing device, to send information to and receive information from that external device.

[0051] The controller 1600 is configured to operate the strapping tool in one of three operating modes (as set by the operator): (1) a manual operating mode; (2) a semi-automatic operating mode; and (3) an automatic operating mode. In the manual operating mode, the controller 1600 operates the motor 800 to rotate the output shaft 810 in the first rotational direction RD1 responsive to the first pushbutton actuator 1410 being actuated and maintained in its actuated state to tension the strap. The controller 1600 operates the motor 800 to cause the output shaft 810 to rotate in the second rotational direction RD2 responsive to the second pushbutton actuator 1420 being actuated to form the strap joint and cut the upper strap layer from the strap supply. In the semi-automatic operating mode, the controller 1600 operates the motor 800 to rotate the output shaft 810 in the first rotational direction RD1 responsive to the first pushbutton actuator 1410 being actuated and maintained in its actuated state to tension the strap.Once the controller 1600 determines that the tension in the strap reaches the preset desired strap tension, the controller 1600 automatically operates the motor 800 to rotate the output shaft 810 in the second rotational direction RD2 to form the strap joint and cut the upper strap layer from the strap supply. In the automatic operating mode, the controller 1600 operates the motor 800 to rotate the output shaft 810 in the first rotational direction RD1 responsive to the first pushbutton actuator 1410 being actuated to tension the strap. Once the controller 1600 determines that the tension in the strap reaches the preset desired strap tension, the controller 1600 automatically operates the motor 800 to rotate the output shaft 810 in the second rotational direction RD2 to form the strap joint and cut the upper strap layer from the strap supply.

[0052] The power supply 1500 is electrically connected to (via suitable wiring and other components) and configured to power several components of the strapping tool 50, including the motor 800 and the controller 1600. The power supply 1500 is a rechargeable battery (such as a lithium-ion or nickel cadmium battery) in this example embodiment, though it may be any other suitable electric power supply in other embodiments.

[0053] Use of the strapping tool 50 to carry out a strapping process including a tensioning cycle in which the strapping tool 50 tensions strap around a load and a sealing cycle in which the strapping tool 50 attaches overlapping upper and lower strap layers to one another via friction welding to form a strap joint and cuts the upper strap layer from the strap supply is described below. The strapping tool 50 is in the automatic mode for the purposes of this example.

[0054] The operator pulls the strap S leading-end first from a strap supply (not shown), wraps the strap around the load, and positions a lower strap layer LL — which includes the leading end of the strap S — below an upper strap layer UL. The operator pulls the hand lever 1000 to pivot the rocker subassembly 500 to the strap-insertion position. While continuing to pull the hand lever 1000, the operator introduces the overlapping upper and lower strap layers UL and LL between the tensioning wheel 395 and the tensioning-and-sealing plate 540, as shown in Figure 9A. The operator then releases the hand lever 1000, which enables suitable biasing elements to force the rocker subassembly 500 to its tensioning-and-sealing position. Eventually, the outer teeth 395ot of the tensioning wheel 395 engage the upper surface of the upper strap layer UL and force the bottom surface of the lower strap layer LL against the toothedupper surface 542u of the body 542 of the tensioning-and-sealing plate 540, as shown in Figure 9B.

[0055] The operator then actuates the first pushbutton actuator 1410 to initiate the strapping process. In response, the controller 1600 starts the tensioning cycle by controlling the motor 800 to begin rotating the output shaft 810 in the first rotational direction RD1. As explained above, the transmission 900 transmits this rotational movement to the driven shaft 310 of the tensioning subassembly 300, which in turn causes the tensioning wheel 395 to rotate in the tensioning rotational direction. As shown n Figure 9C, as the tensioning wheel 395 rotates, it pulls the upper strap layer UL of the strap over the lower strap layer LL, thereby tensioning the strap around the load. The transmission 900 does not transmit rotational movement of the output shaft 810 to the eccentric shaft 710 as this occurs. Throughout the tensioning cycle, the controller 1600 monitors the current drawn by the motor 800. When this current reaches a preset value that is correlated with the preset desired strap tension for this strapping process, the controller 1600 stops the motor 800, thereby completing the tensioning cycle.

[0056] The controller 1600 then automatically starts the sealing cycle by controlling the motor 800 to begin rotating the output shaft 810 in the second rotational direction RD2. As explained above, the transmission 900 transmits this rotational movement to: (1) the eccentric shaft 710 and causes the eccentric shaft 710 to rotate; and (2) the cutter subassembly 600 and causes the cutter subassembly 610 to pivot downward to the cutting position, as shown in Figure 9D. As also explained above, rotation of the eccentric shaft 710 causes the plate mount 530 and the tensioning-and-sealing plate 540 thereon and the cutter mount 620 and the strap cutter 630 thereon to linearly reciprocate in the transverse direction TD relative to the tensioning wheel 395.

[0057] As shown in Figures 10A-10C, the tensioning-and-sealing plate 540 carries a portion of the lower strap layer LL with it during this linear reciprocation while the tensioning wheel 395 maintains the position of the opposing portion of the upper strap layer. This rapid linear reciprocation of this portion of the lower strap layer LL relative to the upper strap layer UL generates friction and heat that locally melts these portions of the upper and lower strap layers. As shown in Figure 11, as the cutter subassembly 600 reaches its cutting position, the teeth 630t of the strap cutter 630 engage the upper surface of the upper strap layer UL rearward of the tensioning wheel 395. The linear reciprocation of the strap cutter 630 causes the teeth 630tto abrade and eventually cut the upper strap layer UL from the strap supply to create a strap tail ST that represents the leading end of the strap in the strap supply. The strap cutter 630 is sized and the cutter subassembly 600 is otherwise configured such that the teeth 630t of the strap cutter 630 do not engage the lower strap layer when the cutter subassembly 600 is in the cutting position. After a preset period or a preset quantity of rotations of the output shaft 810, the controller 1600 controls the motor 800 to stop rotating the output shaft 810, completing the sealing cycle. The melted portions of the upper and lower strap layers join and solidify as they cool, thereby attaching the upper and lower strap layers to form the strap joint and the tensioned strap loop.

[0058] Certain known strapping tools that use friction welding to attach the strap layers to one another include separate assemblies — and sometimes even separate motors — for tensioning and sealing the strap. This can make these devices relatively heavy. Certain known strapping tools include a base plate that separates the tensioning and weld plates from the load and rests on the load during operation. Since the weld plate is rearward of and aligned with the tensioning plate, the base plate is relatively long. This prevents operators from using the strapping tool to strap curved loads with relatively small radii, such as small bundles of metal pipes, because the length of the base plate prevents the strap from retaining adequate tension after the strapping tool is removed from the load.

[0059] The strapping tool of the present disclosure solves these problems. First, linearly reciprocating the tensioning-and-sealing plate to form the strap joint eliminates the need for separate tensioning and welding assemblies (and in some embodiments separate tensioning and welding motors), which renders the tool lighter and easier to use for prolonged periods of time compared to traditional strapping tools with distinct assemblies. Second, elimination of the separate welding assembly enables the base plate of the tool to be shorter in the longitudinal direction than the base plates of traditional strapping tools, which enables the strapping tool of the present disclosure to be used for more applications (such as to strap curved loads with relatively small radii) than many traditional strapping tools. This distinction is illustrated in Figures 12A and 12B. Figure 12A shows a relatively long prior art base plate BP above which a tensioning wheel TW and welder W are positioned. Figure 12B shows the relatively short plate support 514 of the present disclosure above which the tensioning wheel 395 of the present disclosure is positioned. When used to strap identical circular loads L with strap S, more tensionwill be retained in the strap after removal of the base plate when the shorter plate support of the present disclosure is used.

[0060] In the example embodiment described above, a single motor is used to drive the driven shaft of the tensioning subassembly, to drive the eccentric shaft of the drive subassembly, and to pivot the cutting subassembly. In other embodiments, the strapping tool includes two separate motors: a tensioning motor operably connected to the tensioning subassembly and configured to drive the driven shaft during the tensioning cycle and a cutting- and-sealing motor operably connected to the cutting-and-sealing subassembly and configured to drive the eccentric shaft and to pivot the cutting subassembly during the sealing cycle.

[0061] In the example embodiment described above, the plate mount and the tensioning-and-sealing plate thereon are part of the rocker subassembly that is pivotable relative to the tensioning subassembly and, in particular, the tensioning wheel. In other embodiments, the base (or any other suitable component) of the support functions as the plate support and supports the plate mount and the tensioning-and-sealing plate thereon. In these embodiments, the tensioning subassembly is part of the rocker subassembly and is pivotable upward and downward relative to the tensioning-and-sealing plate. In other words, in these embodiments, the tensioning wheel is movable toward and away from the tensioning-and-sealing plate rather than the opposite configuration.

[0062] Other embodiments of the strapping tool may include fewer assemblies, components, and / or features than those included in the strapping tool 50 described above and shown in the Figures. In other words, while the strapping tool 50 includes all the assemblies, components, and features described above, they are independent of one another and may be independently included in other strapping tools.

[0063] In the example embodiments described above, the working assembly is employed as part of a portable handheld strapping tool. The working assembly may be incorporated into any other type of strapping device, such as a general-purpose strapping machine or the strapping head of a special-purpose strapping machine.

Claims

Claims1. A strapping device comprising: a rotatable tensioning wheel; a linearly movable tensioning-and-sealing plate adjacent the tensioning wheel; a rotatable eccentric shaft operably connected to the tensioning-and-sealing plate such that rotation of the eccentric shaft causes the tensioning-and-sealing plate to linearly reciprocate relative to the tensioning wheel; and a motor operably connected to the eccentric shaft and configured to rotate the eccentric shaft.

2. The strapping device of claim 1, further comprising a transmission operably connecting the motor to the eccentric shaft.

3. The strapping device of claim 2, further comprising a driven gear fixed in rotation with the eccentric shaft, wherein the transmission comprises a drive gear and a connector operably connecting the drive gear to the driven gear, wherein the motor is operably connected to the drive gear and configured to rotate the drive gear to drive the connector to rotate the driven gear.

4. The strapping device of claim 2, wherein the transmission operably connects the motor to the tensioning wheel such that the motor is configured to rotate the tensioning wheel.

5. The strapping device of claim 4, wherein the motor comprises an output shaft rotatable in a first rotational direction and a second rotational direction opposite the first rotational direction, wherein the transmission is configured such that: rotation of the output shaft in the first rotational direction is transmitted to the tensioning wheel to cause the tensioning wheel to rotate; and rotation of the output shaft in the second rotational direction is transmitted to the eccentric shaft to cause the eccentric shaft to rotate.

6. The strapping device of claim 1, further comprising a plate mount comprising a plate-mounting portion and a plate-mount driven portion, wherein the tensioning-and-sealing plate is mounted to the plate-mounting portion, wherein the eccentric shaft is operably connected to the plate-mount driven portion such that rotation of the eccentric shaft causes the plate mount to linearly reciprocate.

7. The strapping device of claim 6, wherein the eccentric shaft comprises an eccentric portion, wherein the plate-mount driven portion defines a cavity in which at least part of the eccentric portion is positioned.

8. The strapping device of claim 6, further comprising a plate support to which the plate mount is slidably mounted.

9. The strapping device of claim 8, further comprising a rocker comprising a rocker arm and the plate support, wherein the plate support is connected to the rocker arm, wherein the rocker is pivotable relative to the tensioning wheel between a first position in which a first distance separates the tensioning wheel and the tensioning-and-sealing plate and a second position in which a second distance separates the tensioning wheel and the tensioning-and- sealing plate, wherein the second distance is greater than the first distance.

10. The strapping device of claim 9, wherein the eccentric shaft comprises an eccentric portion, wherein the plate-mount driven portion defines a cavity in which a first portion of the eccentric portion is received when the rocker is in the first position and in which a second portion of the eccentric portion is received when the rocker is in the second position, wherein the second portion is smaller than the first portion.

11. The strapping device of claim 8, further comprising a rocker supporting the tensioning wheel, wherein the rocker is pivotable relative to the tensioning-and-sealing plate between a first position in which a first distance separates the tensioning wheel and the tensioning-and-sealing plate and a second position in which a second distance separates the tensioning wheel and the tensioning-and-sealing plate, wherein the second distance is greater than the first distance.

12. The strapping device of claim 1, further comprising a linearly movable strap cutter, wherein the eccentric shaft is operably connected to the strap cutter such that rotation of the eccentric shaft causes the strap cutter to linearly reciprocate.

13. The strapping device of claim 12, further comprising a cutter mount comprising a cutter-mounting portion and a cutter-mount driven portion, wherein the strap cutter is mounted to the cutter-mounting portion, wherein the eccentric shaft is operably connected to the cuttermount driven portion such that rotation of the eccentric shaft causes the cutter mount to linearly reciprocate.

14. The strapping device of claim 13, wherein the eccentric shaft comprises an eccentric portion, wherein the cutter-mount driven portion defines a cavity in which at least part of the eccentric portion is received.

15. The strapping device of claim 13, further comprising a cutter support to which the cutter mount is slidably mounted, wherein the cutter support is pivotable from a rest position downward to a cutting position.

16. The strapping device of claim 15, wherein the motor is operably connected to the cutter support and configured to pivot the cutter support from the rest position to the cutting position.

17. The strapping device of claim 13, further comprising a plate mount comprising a plate-mounting portion and a plate-mount driven portion, wherein the tensioning-and-sealing plate is mounted to the plate-mounting portion, wherein the eccentric shaft is operably connected to the plate-mount driven portion such that rotation of the eccentric shaft causes the plate mount to linearly reciprocate, wherein the eccentric shaft comprises an eccentric portion, wherein the cutter-mount driven portion defines a cavity in which at least part of the eccentric portion is received, and wherein the plate-mount driven portion defines a cavity in which at least part of the eccentric portion is received.

18. The strapping device of claim 17, further comprising a transmission operably connecting the motor to the eccentric shaft, wherein the transmission operably connects the motor to the tensioning wheel such that the motor is configured to rotate the tensioning wheel, and wherein the motor comprises an output shaft rotatable in a first rotational direction and a second rotational direction, wherein the transmission is configured to: when the output shaft is rotated in the first rotational direction, transmit the rotation of the output shaft to the tensioning wheel to cause the tensioning wheel to rotate; and when the output shaft is rotated in the second rotational direction, transmit the rotation of the output shaft to the eccentric shaft to cause the eccentric shaft to rotate.

19. The strapping device of claim 18, wherein the tensioning-and-sealing plate and the strap cutter are linearly movable in a transverse strap direction, wherein the eccentric shaft is rotatable about an eccentric- shaft axis that is oriented perpendicular to the transverse strap direction.

20. The strapping device of claim 12, wherein the tensioning-and-sealing plate and the strap cutter are linearly movable in a transverse strap direction, wherein the eccentric shaft is rotatable about an eccentric- shaft axis that is oriented transverse to the transverse strap direction.

21. The strapping device of claim 12, wherein the eccentric shaft is operably connected to the tensioning-and-sealing plate and the strap cutter such that rotation of the eccentric shaft causes the tensioning-and-sealing plate and the strap cutter to linearly reciprocate in a substantially synchronous manner.

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