CN208293236U - A kind of computerized emboridering machine send frame apparatus automatically - Google Patents

Abstract

What the utility model provided a kind of computerized emboridering machine send frame apparatus automatically, including symmetrical embroidery machine, the corresponding embroidery machine middle position is equipped with rack, it is fixed in the rack and send frame apparatus, it is described that send frame apparatus include pipeline, loading and unloading lifting structure, mobile manipulator and frame clamp continuous structure, the pipeline is fixed on the rack for gearing frame, loading and unloading lifting structure is fixed on the frame lower in embroidery machine middle position, loading and unloading lifting structure top is equipped with the mobile manipulator being fixed on the rack, the frame clamping continuous structure is fixed on the workbench top of embroidery machine, pipeline can effectively by frame quickly and precisely convey, pass through loading and unloading lifting structure, mobile manipulator and frame clamping continuous structure are quick by frame, accurately it is moved to embroidery machine operating position, it embroiders Operation improves work efficiency, and shortens the downtime of machine, meanwhile, the precision of needlework location in the frame is improved, guarantees the consistency of embroidery needlework location.

Description

A kind of computerized emboridering machine send frame apparatus automatically

Technical field

The utility model belongs to embroidery equipment technical field, and in particular to a kind of computerized emboridering machine send frame apparatus automatically.

Background technique

It embroiders, also referred to as embroiders, also known as " needlework ".It is to draw multi-color cord (silk, suede, line) with embroidered needle knitting by the style of design Thorn, which is sewed, on object (silk, cloth and silk) handles the needle, and is constituted grain pattern or text to embroider mark, is one of national tradition technique of Chinese elite.With The development of computer technology, as gunpowder papermaking and compass, modern age again from foreign countries flow into Computers in China embroider, also just Come in our conceptive deduce of Chinese tradition embroidery, the method for computer programming is carried out using the computer embroidery software of profession to set Meter style and the sequence that takes the needle, are finally reached the mass production of embroidery product, and computer embroidery not only does traditional-handwork embroidery It is relatively perfect to inherit, and solve traditional hand-embroidered and can not complete the status of production quantitatively.

In computerized emboridering machine in the prior art, frame be all it is direct or indirect be fixed on the machine, the process is equal By being accomplished manually the replacement of cloth or frame, not only high labor cost, and also the working efficiency of replacement process is low, downtime It is long, the production model of machine embroidering work automation can not be formed.

Utility model content

The utility model is, downtime long problem low for the replacement of frame and fixed efficiency in the prior art, existing A kind of computerized emboridering machine is provided with frame apparatus is sent automatically, frame can be conveyed automatically, accurate clamping and quickly fixed, and The downtime of machine can be shortened and guarantee the accuracy of needlework location.

What the utility model provided a kind of computerized emboridering machine send frame apparatus automatically, described including symmetrical embroidery machine Corresponding embroidery machine middle position is equipped with rack, is fixed in the rack and send frame apparatus, which is characterized in that is described to send frame apparatus packet Pipeline, loading and unloading lifting structure are included, mobile manipulator and frame clamp continuous structure, and the pipeline is fixed on the rack use In gearing frame, loading and unloading lifting structure is fixed on the frame lower in embroidery machine middle position, and loading and unloading lifting structure top is set There is the mobile manipulator being fixed on the rack, the frame clamping continuous structure is fixed on the workbench top of embroidery machine, also wraps Include the sensor being fixed on the rack on the outside of loading and unloading lifting structure.

Preferably, the pipeline includes the conveyer belt being arranged symmetrically, and conveyer belt is fixed on belt wheel, is passed through between belt wheel Shaft connection, shaft connect motor and power supply, and the pipeline is monolithic construction or segmentation structure, every section of pipeline difference Equipped with a motor, distance is less than the half of the minimum side length of frame between the adjacent conveyor line.

Preferably, the mobile manipulator includes the mobile bracket of orthogonal X-axis, the mobile bracket of Y-axis, the mobile branch of Z axis Frame, the mobile bracket of the X-axis, the mobile bracket of Y-axis, the mobile bracket of Z axis are respectively equipped with mobile terminal and fixing end, the Y-axis bracket Fixing end be fixed on the rack the top of pipeline, the direction of motion of mobile terminal is parallel with pipeline, the mobile bracket of the X-axis Fixing end be fixedly connected with the mobile terminal of Y-axis bracket, the mobile terminal direction of motion of the mobile bracket of X-axis and 2 embroidery machine directions In parallel, the fixing end of the mobile bracket of the Z axis and the mobile terminal of the mobile bracket of X-axis are fixed, the mobile terminal of the mobile bracket of the Z axis The direction of motion is perpendicular to plane where pipeline, further includes the clamp structure for being fixed on Z axis mobile terminal, the clamp structure packet The fixed frame fixed with the mobile bracket mobile terminal of Z axis is included, the both ends of the fixed frame are fixed with driving mechanism, the driving machine The extension end of structure outwardly and is respectively equipped with interconnecting piece, and the bottom end of the interconnecting piece, which is equipped with, moves left and right clamping part.

Preferably, the loading and unloading structure includes the fixed plate fixed with rack, and the bottom of fixed plate is fixed with lifting Cylinder, top are equipped with uplink limiting cylinder and downlink limiting cylinder, and the extension end of the lifting cylinder passes through fixed plate and is equipped with liter Plate drops, and the both ends of the lifter plate are equipped with clamping cylinder and move up and down clamping part, further include fixing and running through solid with lifter plate The guide rod of the guide rod of fixed board, the fixed plate lower end is equipped with limited block.

Preferably, the extension end of the uplink limiting cylinder and downlink limiting cylinder be equipped with block, uplink limiting cylinder and After the extension end of downlink limiting cylinder is stretched out, block is contacted with lifter plate, it can be ensured that lifter plate height and position it is accurate.

Preferably, the frame clamping continuous structure includes frame driving plate, is fixedly connected with block, frame driving plate can embroider It is moved on the workbench of flower machine, fixed connecting plate is fixedly connected with frame driving plate.

Further, the block that is fixedly connected includes fixed drive mechanism and link block, and the link block includes connection bottom Seat, movable plate connect positioning pin and reseting shrapnel, and connection pedestal is fixedly connected with frame driving plate, connect pedestal and movable plate Middle part rotation connection, the upper end side of movable plate are fixed with reseting shrapnel by fastener, and the bottom both ends of reseting shrapnel are fixed Positioning pin is connected, connection positioning pin is located at movable plate upper end to pedestal, the fixed drive mechanism is connected through movable plate, fixed The extension end of driving mechanism can act on the other end of movable plate.

Preferably, the block that is fixedly connected includes fixed drive mechanism and connection locating piece, and the connection locating piece includes Pedestal, movable plate and magnetic absorption part are connected, connection pedestal and movable plate are rotatablely connected, and connection pedestal is fixed with frame driving plate Connection, magnetic absorption part are fixed on the bottom of movable plate one end, and fixed drive mechanism is located at the top of movable plate, the fixed drive The extension end of motivation structure can act on the other end of movable plate.

Preferably, the block that is fixedly connected includes fixed drive mechanism and link block, and the link block includes rotation connection Connection pedestal and movable plate, connection pedestal be fixedly connected with frame driving plate, further include the positioning for being fixed on movable plate upper end Driving mechanism, the mobile terminal bottom of the positioning drive mechanisms are equipped with fixed locating stud, and the fixed locating stud runs through movable plate To connection pedestal.

Preferably, the fixed drive mechanism and positioning drive mechanisms are cylinder or electromagnet.

The beneficial effects of the utility model are:

1, pipeline can effectively by frame quickly and precisely convey, reduce labor workload；

2, by loading and unloading lifting structure, mobile manipulator and frame clamping continuous structure that frame is quick, it is accurate to move It moves to embroidery machine operating position, carries out embroidering operation, improve work efficiency, shorten the downtime of machine, meanwhile, it mentions High position precision of the frame on embroidery machine.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of the utility model；

Fig. 2 is the connection structure signal of frame and pipeline, loading and unloading lifting structure, mobile manipulator in the utility model The partial view of figure；

Fig. 3 be pipeline in the utility model, loading and unloading lifting structure, mobile manipulator connection another angle knot The partial view of structure schematic diagram；

Fig. 4 is the partially schematic of the structural schematic diagram in the utility model between loading and unloading lifting structure and mobile manipulator Figure；

Fig. 5 be loading and unloading lifting structure and rack in the utility model, pipeline side view structural schematic diagram；

Fig. 6 is the structural schematic diagram of pipeline in the utility model；

Fig. 7 is the structural schematic diagram of mobile manipulator in the utility model；

Fig. 8 is the structural schematic diagram of frame clamping continuous structure in the utility model；

Fig. 9 is the structural schematic diagram of the first embodiment of link block in the utility model；

Figure 10 is the structural schematic diagram of second of embodiment of link block in the utility model；

Figure 11 is the structural schematic diagram of the third embodiment of link block in the utility model；

Figure 12 is part A enlarged structure schematic diagram in Fig. 2；

Figure 13 is the enlarged structure schematic diagram of part B in Fig. 3；

Wherein, 1, embroidery machine, 2, frame, 3, pipeline, 31, shaft, 32, belt wheel, 33, motor, 34, conveyer belt, 35, Spacer column, 4, mobile manipulator, 41, the mobile bracket of Y-axis, 42, the mobile bracket of X-axis, 43, the mobile bracket of Z axis, 44, fixed frame, 45, clamp drive mechanism, 46, interconnecting piece, 47, move left and right clamping part, 5, frame clamp continuous structure, 51, be fixedly connected with block, 510, fixed drive mechanism, 511, connection pedestal, 512, connection positioning pin, 513, movable plate, 514, reseting shrapnel, 515, magnetism Adsorption piece, 516, fixed locating stud, 517, positioning drive mechanisms, 52, frame driving plate, 6, sensor, 7, loading and unloading lifting knot Structure, 71, lifting cylinder, 72, fixed plate, 73, lifter plate, 74, clamping cylinder, 75, move up and down clamping part, 76, uplink limit Cylinder, 77, downlink limiting cylinder, 760, block, 78, guide rod, 79, limited block, 8, rack.

Specific embodiment

Technical solution described in the utility model is described without limitation below in conjunction with attached drawing, in order to the public More fully understand the technology contents.

Embodiment one

As shown in Fig. 1 to Fig. 3 and Figure 13, a kind of computerized emboridering machine send frame apparatus automatically, including symmetrical embroidery Machine 1, corresponding 1 middle position of embroidery machine are equipped with rack 8, are fixed in the rack 8 and send frame apparatus, which is characterized in that institute Stating and sending frame apparatus includes pipeline 3, and loading and unloading lifting structure 7, mobile manipulator 4 and frame clamp continuous structure 5, the conveying Line 3 is fixed in rack 8 for gearing frame 2, and loading and unloading lifting structure 7 is fixed under the rack 8 in 1 middle position of embroidery machine Portion, 7 top of loading and unloading lifting structure are equipped with the mobile manipulator 4 being fixed in rack 8, and the frame clamping continuous structure 5 is solid It is scheduled on the workbench top of embroidery machine 1, further includes the sensor 6 being fixed on the outside of loading and unloading lifting structure 7 in rack 8, into one Step, the pipeline 3, loading and unloading lifting structure 7, mobile manipulator 4, frame clamping continuous structure 5 and sensor 6 connect PLC.Wherein, sensor 6 can be position sensor in the present embodiment.

As shown in Figure 5 and Figure 6, the pipeline includes the conveyer belt 34 being arranged symmetrically, and conveyer belt 34 is fixed on belt wheel 32 On, it is connected between belt wheel 32 by shaft 31, shaft 31 connects motor 33 and power supply, and the pipeline is monolithic construction or divides Segmentation structure, every section of pipeline are respectively equipped with a motor 33, and distance is less than the minimum edge of frame between the adjacent conveyor line Long half.Pipeline 3 is segmentation structure in the present embodiment, is divided into two sections, by dividing pipeline 3 for multistage, Ke Yiti Degree of stability of the high frame 2 on pipeline 3.Further, right by setting spacer column 35 between symmetrical conveyer belt 34 In various sizes of frame 2, shaft 31 and spacer column 35 can be replaced, changes the distance between band, to adapt to frame 2.

As shown in Fig. 3, Fig. 4, Fig. 7, the mobile manipulator 4 includes the mobile bracket 42 of orthogonal X-axis, Y-axis movement The mobile bracket 43 of bracket 41, Z axis, the mobile bracket 42 of the X-axis, the mobile bracket 41 of Y-axis, the mobile bracket 43 of Z axis are respectively equipped with shifting Moved end and fixing end, the fixing end of the Y-axis bracket are fixed on the top of pipeline 3 in rack 8, the direction of motion of mobile terminal with Pipeline 3 is parallel, and the fixing end of the mobile bracket 42 of the X-axis is fixedly connected with the mobile terminal of Y-axis bracket, the mobile bracket 42 of X-axis The mobile terminal direction of motion it is parallel with 21 directions of embroidery machine, the fixing end and the mobile bracket 42 of X-axis of the mobile bracket 43 of the Z axis Mobile terminal fix, the mobile terminal direction of motion of the mobile bracket 43 of the Z axis is to further include perpendicular to 3 place plane of pipeline It is fixed on the clamp structure of Z axis mobile terminal, the clamp structure includes the fixed frame fixed with mobile 43 mobile terminal of bracket of Z axis 44, the both ends of the fixed frame 44 are fixed with clamp drive mechanism 45, the extension end of the clamp drive mechanism 45 outwardly and It is respectively equipped with interconnecting piece 46, the bottom end of the interconnecting piece 46, which is equipped with, moves left and right clamping part 47.The mobile bracket of the X-axis being mutually shifted 42, guide rail is equipped between the mobile bracket 41 of Y-axis and the mobile bracket 43 of Z axis to be oriented to, meanwhile, mobile interconnecting piece 46 and fixed Guide rail also is provided between frame 44.

Further, the shown section for moving left and right clamping part 47 is V-arrangement, convenient for clamping to frame 2.

As shown in Fig. 3, Fig. 4, Figure 12, the loading and unloading structure includes the fixed plate 72 fixed with rack 8, fixed plate 72 Bottom is fixed with lifting cylinder 71, and top is equipped with uplink limiting cylinder 76 and downlink limiting cylinder 77, the lifting cylinder 71 Extension end pass through fixed plate 72 and be equipped with lifter plate 73, the both ends of the lifter plate 73 are equipped with clamping cylinder 74 and move up and down folder Portion 75 is held, further includes being fixed with lifter plate 73 and on the guide rod 78 of fixed plate 72, the guide rod 78 of 72 lower end of fixed plate Equipped with limited block 79.

As shown in figure 12, the extension end of the uplink limiting cylinder 76 and downlink limiting cylinder 77 is equipped with block 760, uplink After the extension end of limiting cylinder 76 and downlink limiting cylinder 77 is stretched out, block 760 is contacted with lifter plate 73.Gas is limited by uplink The block of cylinder and downlink limiting cylinder respectively with the contact of lifter plate, it can be ensured that lifter plate height and position it is accurate.

As shown in figure 8, the frame clamping continuous structure 5 includes frame driving plate 52, it is fixedly connected with block 51, frame driving Plate 52 can move on the workbench of embroidery machine 1, and fixed connecting plate is fixedly connected with frame driving plate 52.

As shown in figure 9, the block 51 that is fixedly connected includes fixed drives as the first embodiment for being fixedly connected with block 51 Motivation structure 510 and link block, the link block include connection pedestal 511, and movable plate 513 connects positioning pin 512, and resets bullet Piece 514, connection pedestal 511 is fixedly connected with frame driving plate 52, connects and be rotatablely connected in the middle part of pedestal 511 and movable plate 513, living The upper end side of movable plate 513 is fixed with reseting shrapnel 514 by fastener, and the bottom both ends of reseting shrapnel 514 are fixedly connected fixed Position pin 512, for connection positioning pin 512 through movable plate 513 to connection pedestal 511, the fixed drive mechanism 510 is located at movable plate 513 upper ends, the extension end of fixed drive mechanism 510 can act on the other end of movable plate 513.

As shown in Figure 10, as second of embodiment for being fixedly connected with block 51, the block 51 that is fixedly connected includes fixing Driving mechanism 510 and connection locating piece, the connection locating piece include connection pedestal 511, movable plate 513 and magnetic absorption part 515, connection pedestal 511 and movable plate 513 are rotatablely connected, and connection pedestal 511 is fixedly connected with frame driving plate 52, magnetic absorption Part 515 is fixed on the bottom of 513 one end of movable plate, and fixed drive mechanism 510 is located at the top of movable plate 513, the fixed drive The extension end of motivation structure 510 can act on the other end of movable plate 513.

As shown in figure 11, as the third embodiment for being fixedly connected with block 51, the block 51 that is fixedly connected includes fixing Driving mechanism 510 and link block, the link block include the connection pedestal 511 and movable plate 513 of rotation connection, connect pedestal 511 are fixedly connected with frame driving plate 52, further include the positioning drive mechanisms 517 for being fixed on 513 upper end of movable plate, the positioning The mobile terminal bottom of driving mechanism 517 is equipped with fixed locating stud 512, and the fixed locating stud 512 is through movable plate 513 to connection Pedestal 511.

Wherein, the fixed drive mechanism 510 and positioning drive mechanisms 517 are cylinder or electromagnet.

Working principle: when having frame 2 respectively on two 1 devices of embroidery machine, then the frame 2 of pipeline 3 moves to sensing When 6 position of device, frame 2 will be stopped, and PLC sending is waited to send frame signal；

As long as the frame 2 of pipeline 3 is by first motion to upper when one of them does not have frame 2 on two embroidery machines 1 7 position of blanking lifting structure, after uplink limiting cylinder 76 stretches out, lifting cylinder 71, which is then up raised up to, encounters upper shape limiting cylinder Block 760, at this moment move up and down clamping part 75 and then just touch frame 2 on conveyer belt, then move up and down clamping part 75 clamp frame 2 under the action of clamping cylinder 74, after uplink limiting cylinder 76 resets, on lifting cylinder 71 will continue Rise, can not rise until because encountering limited block 79, at this point, frame 2 be exactly in mobile manipulator 4 move left and right clamping part 47 Crawl position moves up and down the opening of clamping part 75 after mobile manipulator 4 grabs, and lifting cylinder 71 is begun to decline, mechanically moving Frame 2 is sent on embroidery machine 1 and is embroidered by frame clamping continuous structure 5 transmission and fixed assassination of going forward side by side by hand 4.Conversely, when machine is embroidered After the completion of flower, frame 2 is driven to the top of loading and unloading lifting structure 7 by moving structure hand, moves up and down clamping part 75 for frame The crawl of frame 2 receives, and after rear 77 stretching of so downlink limiting cylinder, lifting cylinder 71 drops to the block 760 of downlink limiting cylinder 77, Frame 2 is just fallen on pipeline 3 at this time, moves up and down the opening of clamping part 75, after downlink limiting cylinder 77 resets, lifting cylinder 71, which will continue decline, resets.

It should be understood that it is not limitation to the technical solution that above content, which includes attached drawing, in fact, identical or Under approximate principle, to the improvement that the technical solution carries out, shape, size, material used including Each part, and The equivalent replacement of essentially identical functional structure, all within the utility model technical solution claimed.

Claims (10)

1. a kind of computerized emboridering machine send frame apparatus automatically, including symmetrical embroidery machine, the corresponding embroidery machine interposition Organic frame is installed, is fixed in the rack and send frame apparatus, which is characterized in that described to send frame apparatus include pipeline, loading and unloading Lifting structure, mobile manipulator and frame clamp continuous structure, and the pipeline is fixed on the rack for gearing frame, up and down Material lifting structure is fixed on the frame lower in embroidery machine middle position, and loading and unloading lifting structure top, which is equipped with, to be fixed on the rack Mobile manipulator, the frame clamping continuous structure are fixed on the workbench top of embroidery machine, further include loading and unloading lifting structure The sensor that outside is fixed on the rack.

2. computerized emboridering machine according to claim 1 send frame apparatus automatically, it is characterised in that: the pipeline includes pair Claim the conveyer belt of arrangement, conveyer belt is fixed on belt wheel, is connected between belt wheel by shaft, and shaft connects motor and power supply, defeated There are also spacer columns between line sending is suitable for the conveying of the aluminium chassis of different size, institute by the variation of spacer column and shaft size Stating pipeline is monolithic construction or segmentation structure, and every section of pipeline is respectively equipped with a motor, the adjacent conveyor line it Between distance be less than frame minimum side length half.

3. computerized emboridering machine according to claim 1 send frame apparatus automatically, it is characterised in that: the mechanically moving handbag Include the mobile bracket of orthogonal X-axis, the mobile bracket of Y-axis, the mobile bracket of Z axis, the mobile bracket of the X-axis, Y-axis mobile bracket, Z The mobile bracket of axis is respectively equipped with mobile terminal and fixing end, and the fixing end of the Y-axis bracket is fixed on the rack the top of pipeline, The direction of motion of mobile terminal is parallel with pipeline, the fixed company in mobile terminal of the fixing end and Y-axis bracket of the mobile bracket of the X-axis It connects, the mobile terminal direction of motion of the mobile bracket of X-axis is parallel with 2 embroidery machine directions, the fixing end and X of the mobile bracket of the Z axis The mobile terminal of the mobile bracket of axis is fixed, the mobile terminal direction of motion of the mobile bracket of the Z axis be perpendicular to plane where pipeline, It further include the clamp structure for being fixed on Z axis mobile terminal, the clamp structure includes the fixation fixed with the mobile bracket mobile terminal of Z axis Frame, the both ends of the fixed frame are fixed with driving mechanism, and the extension end of the driving mechanism outwardly and is respectively equipped with interconnecting piece, The bottom end of the interconnecting piece is equipped with and moves left and right clamping part.

4. computerized emboridering machine according to claim 1 send frame apparatus automatically, it is characterised in that: the loading and unloading structure packet The fixed plate fixed with rack is included, the bottom of fixed plate is fixed with lifting cylinder, and top is equipped with uplink limiting cylinder and downlink Limiting cylinder, the extension end of the lifting cylinder pass through fixed plate and are equipped with lifter plate, and the both ends of the lifter plate, which are equipped with, clamps gas Cylinder and clamping part is moved up and down, further includes the guide rod that fixed plate is fixed and run through with lifter plate, the guide rod of the fixed plate lower end It is equipped with limited block.

5. computerized emboridering machine according to claim 4 send frame apparatus automatically, it is characterised in that: the uplink limiting cylinder It is equipped with block with the extension end of downlink limiting cylinder, after the extension end stretching of uplink limiting cylinder and downlink limiting cylinder, block It is contacted with lifter plate.

6. computerized emboridering machine according to any one of claim 1 to 5 send frame apparatus automatically, it is characterised in that: described It includes frame driving plate that frame, which clamps continuous structure, is fixedly connected with block, and frame driving plate can move on the workbench of embroidery machine, Fixed connecting plate is fixedly connected with frame driving plate.

7. computerized emboridering machine according to claim 6 send frame apparatus automatically, it is characterised in that: described to be fixedly connected with block packet Fixed drive mechanism and link block are included, the link block includes connection pedestal, and movable plate connects positioning pin and reseting shrapnel, even It connects pedestal to be fixedly connected with frame driving plate, be rotatablely connected in the middle part of connection pedestal and movable plate, the upper end side of movable plate passes through Fastener is fixed with reseting shrapnel, and the bottom both ends of reseting shrapnel are fixedly connected with positioning pin, and connection positioning pin runs through movable plate extremely Pedestal is connected, the fixed drive mechanism is located at movable plate upper end, and the extension end of fixed drive mechanism can act on movable plate The other end.

8. computerized emboridering machine according to claim 6 send frame apparatus automatically, it is characterised in that: described to be fixedly connected with block packet Fixed drive mechanism and connection locating piece are included, the connection locating piece includes connection pedestal, movable plate and magnetic absorption part, connection Pedestal and movable plate are rotatablely connected, and connection pedestal is fixedly connected with frame driving plate, and magnetic absorption part is fixed on movable plate one end Bottom, fixed drive mechanism is located at the top of movable plate, and the extension end of the fixed drive mechanism can act on movable plate The other end.

9. computerized emboridering machine according to claim 6 send frame apparatus automatically, it is characterised in that: described to be fixedly connected with block packet Fixed drive mechanism and link block are included, the link block includes the connection pedestal and movable plate of rotation connection, connects pedestal and frame Frame driving plate is fixedly connected, and further includes the positioning drive mechanisms for being fixed on movable plate upper end, the movement of the positioning drive mechanisms Bottom is held to be equipped with fixed locating stud, the fixed locating stud is through movable plate to connecting pedestal.

10. computerized emboridering machine according to any one of claims 7 to 9 send frame apparatus automatically, it is characterised in that: described Fixed drive mechanism and positioning drive mechanisms are cylinder or electromagnet.