DE102011017170A1 - Stroke-limiting device of linear actuator, has cable traction mechanism that is installed at telescopic pipe such that retraction or extension of telescopic pipe is stopped when pipe is drawn inwardly or outwardly to final position - Google Patents

Abstract

The device has a movable structure that comprises a rod (20) which passes through a through-hole provided in a housing (10). A block (30) is attached to rod of movable structure. A pair of switches (40,40') is arranged according to the position of block. Each switch is provided with an electrical signal trigger unit and release unit. A cable traction mechanism (50) is installed at a telescopic pipe (85) and is connected with movable structure such that retraction or extension of telescopic pipe is stopped when telescopic pipe is drawn inwardly or outwardly to final position.

Description

FIELD OF THE INVENTION

The present invention relates to a linear drive and more particularly to a stroke limiting device of a linear drive and a cable reeling mechanism thereof.

BACKGROUND OF THE INVENTION

Various types of linear actuators are available on the market, where there is one type of linear drive in which an electric motor, an outer tube and a lead screw driven and rotated by the electric motor are installed on the base. In addition, the lead screw includes a telescopic tube installed on the outside of the lead screw and an outer tube surrounding the outside of the telescopic tube with one end of the outer tube fixed to the base so that the telescopic tube can be driven by the electric motor the guide screw with respect to the outer tube in the axial direction linearly moved back and forth. However, during operation of the linear actuator, users can not determine if the telescopic tube has already moved to the end of the stroke or not, however, the telescope is operated continuously even if the telescopic tube has moved to the end of the stroke, making the linear drive light can be damaged.

In order to solve the above problems, the manufacturers have developed a linear actuator with a stroke limiting device in which a switch is separately installed at both ends of the outer tube, and a block projecting from one end of the telescopic tube is provided around the Retracting the telescoping tube inwardly or moving it outwardly to an end position, the block contacting each of the switches to stop the electric motor to allow the linear drive to be controlled and operated to the limit of the stroke.

Although the above structure accomplishes the purpose of controlling and operating the linear actuator up to the limit of the stroke, however, the switches are installed inside the outer tube, so that the outer tube must have an extra area for receiving each switch, thus not only an increased degree of difficulty arises in the production of the outer tube, but also higher material costs occur. Furthermore, the switches are installed separately at both ends of the outer tube, so that most parts of the linear drive for the maintenance and repair of damaged components must be removed, making the maintenance and repair work more difficult and uncomfortable. For linear actuators with a particular shape or specification, the above stroke limiting device can not be installed or used. Obviously, the conventional stroke limiting device requires improvements.

SUMMARY OF THE INVENTION

Therefore, it is a primary object of the present invention to provide a stroke limiting device of a linear actuator. By building each individual component, little space is required to control an end position over a long distance.

In order to achieve the above object, the present invention provides a stroke limiting device of a linear actuator, the linear drive comprising a base and a telescopic tube; the stroke limiting device comprises a housing, a movable member, a pad, a pair of switches, and a cable winder mechanism, the housing being fixed to the base, and the housing having a wall plate and a through hole formed in the wall plate; the movable member comprises a rod which is passed through and connected to the through hole and which can move the housing; the log is attached to the staff; the pair of switches are fixed to the housing at positions corresponding to the block, and each of the switches has a triggering part provided for contacting the pad to generate an electrical signal, the triggering parts respectively at two opposite ends of a pad Movement paths of the block are arranged; the cable reeling mechanism is installed on the telescopic tube and is moved together with the telescopic tube, the cable reeling mechanism comprising a cable and one end of the cable connected to the movable element; therefore, when the telescoping tube is retracted inwardly to an end position, the rod is pushed and moved together with the block, the block contacting one of the trip members to stop retraction of the telescoping tube; and when the telescoping tube has moved outwardly to an end position, the cable pulls and moves the rod and pad together, the pad contacting the other trip member to stop movement of the telescoping tube.

It is another object of the present invention to provide a cable reel mechanism of a linear drive that can roll up a cable to prevent a loose cable from winding around internal components.

In order to achieve the above object, the present invention provides a Cable reeling mechanism of a linear drive ready, wherein the stroke-limiting device comprises a movable member; the cable reeling mechanism comprises a base, a reeling wheel, a coil spring and a cable, the base having a protruding pin extending from the base; the Aufrollrad is rotatably connected to the protruding bolt; one end of the coil spring is attached to the protruding bolt; and the other end is connected to the Aufrollrad; both ends of the cable are connected to the Aufrollrad and the linear drive accordingly; and the Aufrollrad is elastically driven by the coil spring to rotate the Aufrollrad so that the cable is wound up.

The present invention further has the following effects and uses the inclined surfaces of the pad to contact the trigger parts, so that a maximum distance can be made in a small space and achieve a generally downsized structure. With the installation of the return spring, it can be automatically returned to its central position when external forces no longer act on the block. The cable winder mechanism is used to automatically wind up the cable when no force is applied to the winder wheel to prevent internal components from being wrapped or pulled out. By adjusting the screw which is passed through and connected to the end plate of the telescopic tube, the user can make an external fine adjustment of the movement path of the telescopic tube.

BRIEF DESCRIPTION OF THE DRAWINGS

1 Fig. 11 is an exploded perspective view of a stroke limiting device according to the present invention used in a linear actuator;

2 Fig. 11 is an exploded perspective view of a stroke limiting device according to the present invention;

3 Fig. 11 is an exploded perspective view of a cable reeling mechanism according to the present invention;

4 Fig. 10 is a sectional view of a cable winder mechanism according to the present invention;

5 Fig. 10 is a schematic view of a stroke limiting device according to the present invention used in a linear drive;

6 is a sectional view of a stroke limiting device according to the present invention, which is used in a linear drive;

7 Figure 9 is a first schematic view of the use of a stroke limiting device of a linear actuator according to the present invention; and

8th Figure 9 is a second schematic view of the use of a stroke limiting device of a linear actuator according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The technical characteristics and contents of the present invention will become apparent from the following detailed description and the accompanying drawings. The drawings are merely for the purpose of illustrating the present invention, but are not intended to be limiting of the scope of the invention.

Referring to 1 In a stroke limiting device of a linear drive and a cable winding mechanism thereof according to the present invention, the stroke limiting device comprises 1 a housing 10 , a moving element 20 , a log 30 , a pair of switches 40 . 40 ' and a cable reeling mechanism 50 ,

Referring to 2 is the housing 10 made of plastic and includes a base plate 11 , a pair of wall plates 12 and a pair of side plates 13 extending respectively from the edges of the bottom plate 11 starting to extend upward, with each wall plate 12 with a corresponding side plate 13 is connected and every wall plate 12 a corresponding through hole 14 includes.

The moving element 20 includes a rod 21 and a stop element 22 where a pair of separate slots 211 centrally at the bar 21 is formed, and wherein a screw thread portion 212 at one end of the staff 21 is formed, so the rod 21 in the through hole 14 introduced and associated with this and with respect to the housing 10 can be linearly moved back and forth. The stop element 22 has a substantially stepped shape and includes a stop area 221 , a through hole 222 at the stop element 22 on one side of the stop area 221 is formed, and a first screw hole 223 where the stop element 22 the staff 21 through the through hole 222 wrapped and screw threaded section 212 of the staff 21 secured with a nut, with the stopper element 22 in an outdoor area of the wall plate 12 located. In addition, the movable element comprises 20 This embodiment further includes a pair of return springs 23 . 23 ' that is elastic between the logs 30 and an inside of the wall plate 12 are trapped (as in 1 shown), so that the return springs 23 . 23 ' if there is no external force left on the block 30 acts, can move back to their central position.

The log 30 This preferred embodiment has substantially an octagonal shape, but the invention is not limited to such a shape. The log 30 has two pairs of sloping surfaces 31 and an axle hole 32 on that in the log 30 is formed and permeates it, so that when the log 30 the staff 12 through the axle hole 32 wrapped and a circlip 24 for locking the respective position of the slot 211 was provided, the log 30 , which at a central point of the staff 21 attached, together with the rod 21 can be moved, with the return springs 23 . 23 ' elastic between one side of the block 30 and an inside of the wall plate 12 are trapped.

Each of the position of the log 30 corresponding switches 40 . 40 ' is in an interior of the housing 10 attached, and each switch 40 . 40 ' has a trigger part 41 . 41 ' on which of the logs 30 can be contacted to generate an electrical signal, wherein the trigger parts 41 . 41 ' at each of front and rear opposite ends of a movement path of the pad 21 are arranged.

Referring to the 3 and 4 includes the cable winder mechanism 50 One Base 51 , a Aufrollrad 52 , a spiral spring 53 and a cable 54 , where the base 51 from a lower housing plate 511 and an upper housing plate 512 There is a protruding bolt 513 from a central position of the lower housing plate 511 starting out, an incision 514 at a central location of the protruding bolt 513 is formed, the upper housing plate 512 and the lower housing plate 511 are fastened together by a screw fastener such as a screw, a bolt hole 515 and a screw hole 516 accordingly on both sides of the base 51 are trained, and the base 51 a cable entry hole 517 includes the corresponding protruding bolt 513 is trained.

The Aufrollrad 52 is rotatable with the protruding bolt 513 connected and in the base 51 recorded, and the Aufrollrad 52 consists of an outer wheel 521 and an inner ring 522 , which is separate in the interior of the outer wheel 521 is formed, with a projecting edge 523 from the edge of the outer wheel 521 each extending upwards and downwards to prevent the cable 54 from the outside wheel 521 falls off, with the inner ring 522 consists of three sheet plates.

The spiral spring 53 is formed by bending and rolling a metal plate, and has an insertion portion 531 , the center of the coil spring 53 is formed, and a chop section 532 formed on an edge of its outer periphery. The spiral spring 53 is in the interior of the inner ring 522 installed, with the insertion section in the incision 514 of the protruding bolt 513 inserted and secured therein, and wherein the neck portion 532 in the inner ring 522 is hooked.

One end of the cable 54 is through the cable entry hole 517 performed and on the Aufrollrad 52 attached, and the other end of the cable 54 is through the screw with the first screw hole 223 bolted and on the stop element 22 attached (as in 1 shown).

Referring to the 5 and 6 includes a linear drive 8th in the case of a stroke-limiting device 1 is applied according to the present invention, a basis 81 , an electric motor 82 , a transmission mechanism 83 , a solid pipe 84 and a telescopic tube 85 (as in 1 shown), the electric motor 82 and the solid tube 84 on the base 81 attached and arranged substantially in an L-shape. The transmission mechanism 83 includes a lead screw 831 where one end of the lead screw 831 in the base 81 is installed and by an electric motor 82 is driven and rotated via a Schneckenenzahnradanordnung. The telescopic tube 85 includes an inner tube 851 and an outer tube 852 , where the outer tube 852 the outer circumference of the solid tube 84 wrapped and the inner tube 851 A mother 853 Includes, with the guide screw 831 bolted and transmits to this and in the interior of the fixed pipe 84 is attached, and wherein the inner tube 851 and the outer tube 852 over an end plate 854 attached to each other and connected to each other. During assembly, a bolt passes through the housing 10 performed and based on 81 attached (as in 1 shown), and each switch 40 . 40 ' becomes electric with an electric motor 82 connected (not shown in the figure).

Referring to the 3 and 6 includes the cable winder mechanism 50 the present invention further comprises a guide pin 55 and an adjusting screw 56 where one end of the guide pin 55 at the end plate 854 of the telescopic tube 85 is attached, the other end of the guide pin 55 from the bolt hole 515 protrudes, and the adjusting screw 56 and the guide pin 55 are arranged parallel to each other. The adjusting screw 56 is through the end plate 854 of the telescopic tube 85 performed and in the screw hole 516 the base 51 screwed in to the movement path of the telescopic tube 85 externally fine tune.

Referring to 7 becomes the Aufrollrad 52 when the telescopic tube 85 is drawn inward during operation, by the coil spring 53 elastically driven, so that the Aufrollrad 52 Turn counterclockwise to the cable 54 roll up. If the telescopic tube 85 internally retracted to an end position becomes an end of a nut 853 for resting and moving the stop area 221 of the stoppage 22 used, so the rod 20 the log 30 causes a joint movement, the inclined surface 31 at the back of the log 30 for touching and resting the trigger part 41 of the switch 40 is provided to the operation of the electric motor 82 that with the switch 40 is electrically connected, stop, and retracting the telescopic tube 85 to stop.

Referring to 8th is the cable rewind mechanism 50 when the telescopic tube 85 is extended to the outside, at the end plate 854 of the telescopic tube 85 fastened so that it joins together with the telescopic tube 85 moved outward. Now pull the cable 54 on the retractor wheel so that it rotates clockwise to the cable 54 release. If the telescopic tube 85 is extended to an end position, is the cable 54 completely unrolled. If the telescopic tube 85 continues to extend, pulls the cable 50 the staff 20 and the log 30 together outward, with the sloping surface 31 at the front of the log 30 the trigger part 41 ' of the switch 40 ' touch and rest on this to the operation of the electric motor 82 that with the switch 40 ' is electrically connected, stopping and extending the telescopic tube 85 to stop.

In summary of the above description, the stroke limiting device of the linear actuator and the cable winding mechanism according to the present invention improve the prior art and satisfy the requirements of a patent application, and are therefore duly filed as a patent application.

While the invention has been described by way of specific embodiments, numerous modifications and variations can be made thereto by those skilled in the art without departing from the scope of the invention as defined by the claims.

Claims (19)

A stroke-limiting device of a linear drive, wherein the linear drive comprises a base and a telescopic tube, and the stroke-limiting device comprises: a housing fixed to the base, the housing having a wall plate in which a through hole is formed; a movable member that includes a rod that extends through and is connected to the through hole and that can move the housing; a log attached to the rod; a pair of switches mounted on the housing at positions corresponding to the pad, each of the switches having a trigger portion provided to contact the pad to generate an electrical signal, the trip portions being respectively at two opposite ends of a pad Movement paths of the block are arranged; and a cable reeling mechanism installed on and moved together with the telescopic tube, the cable reeling mechanism comprising a cable and an end of the cable connected to the movable member, wherein, when the telescoping tube is retracted inwardly to an end position, the rod and pad are pushed together and moved, and the pad contacts one of the trigger members to stop retraction of the telescoping tube; and when the telescopic tube is extended outwardly to an end position, the cable pulls and moves the rod and the pad together, and the pad contacts the other triggering member to stop the movement of the telescopic tube. A stroke limiting linear actuator according to claim 1, wherein the movable member further comprises a stop member connected to the rod and formed outside the housing, and wherein the stop member comprises a stop region for retracting and resting the telescopic tube. The stroke limiting linear drive apparatus of claim 1, wherein the rod comprises a pair of slots formed thereon, the block including an axle bore for wrapping the rod, and wherein a locking ring locks with the slot and positions the pad. A stroke limiting linear actuator according to claim 1, wherein the pad comprises a pair of inclined surfaces provided for contacting and resting the trigger member. A stroke limiting linear actuator according to claim 1, wherein the movable member further comprises a pair of return springs, which are elastically clamped between the block and the wall plate. The linear motion stroke limiting device of claim 1, wherein the cable winder mechanism further comprises a base, a rolling wheel and a coil spring, the base being installed on the telescopic tube with a protruding pin extending from the base, the rolling wheel being rotatably connected to the protruding pin with one end of the coil spring secured to the protruding pin, another end of the coil spring being connected to the reeling wheel, and the cable being provided for winding and rolling on the reeling wheel. The linear motion stroke limiting device of claim 6, wherein the base comprises a lower housing plate and an upper housing plate connected to the lower housing plate, the protruding stud extending from the lower housing plate, and wherein the rolling wheel is supported by the upper housing plate and the lower housing plate is received. A stroke limiting linear actuator according to claim 7, wherein the base has a cable entry hole, and wherein the cable is inserted into the cable entry hole and fixed on the movable member. A stroke limiting linear drive apparatus according to claim 6, further comprising an adjusting screw, the base having a screw hole, the telescopic tube having an end plate, and wherein the adjusting screw is passed through the end plate and screwed into the screw hole. A stroke limiting linear drive apparatus according to claim 9, further comprising a guide pin, the base having a bolt hole, one end of the guide pin fixed to the end plate and the other end passed through the bolt hole, and the adjusting screw and the guide pin being arranged in parallel , The stroke limiting device of a linear actuator according to claim 6, wherein the protruding pin has an incision, wherein the Aufrollrad comprises an inner ring, wherein the coil spring an insertion portion which is formed at a central location of the coil spring, and a hook portion, and an outer periphery of the coil spring is formed, wherein the insertion portion is inserted into the recess and fixed therein, and wherein the hook portion is hooked to the inner ring. 10. The linear motion stroke limiting device of claim 11, wherein the rolling wheel further comprises an outer wheel formed on the inner ring and provided for winding the cable, and wherein the outer wheel includes a protruding edge extending up and down from the outer wheel respectively. Cable reeling mechanism of a linear drive, comprising: a base having a projecting pin extending from the base; a Aufrollrad which is rotatably connected to the projecting pin; a coil spring having one end fixed to the protruding pin and the other end connected to the reeling wheel; and a cable whose two ends are attached to the Aufrollrad or on the linear drive; wherein the Aufrollrad is elastically driven by the coil spring to rotate the Aufrollrad so that the cable is rolled up. A cable reeling mechanism of a linear drive according to claim 13, wherein the base comprises a lower housing plate and an upper housing plate which is connected to the lower housing plate, wherein the projecting bolt extending from the lower housing plate, and wherein the Aufrollrad of the upper housing plate and the lower housing plate is added. A cable reeling mechanism of a linear drive according to claim 14, wherein the base has a cable entry hole, and wherein the cable is inserted into the cable entry hole and fixed on the Aufrollrad. A cable reeling mechanism of a linear drive according to claim 13, further comprising an adjusting screw, wherein the base has a screw hole, wherein the linear drive comprises a telescopic tube, wherein the telescopic tube has an end plate, and wherein the adjusting screw is passed through the end plate and screwed into the screw hole. The cable reeling mechanism of a linear drive according to claim 16, further comprising a guide pin, wherein the base has a bolt hole, wherein one end of the guide pin is fixed to the end plate and the other end is inserted into the bolt hole, and wherein the adjusting screw and the guide pin are arranged parallel to each other , A cable reeling mechanism of a linear drive according to claim 13, wherein the protruding pin has an incision, wherein the reeling wheel comprises an inner ring, wherein the coil spring has an insertion portion which at a central location of the Coil spring is formed, and a hook portion which is formed on an outer circumference of the coil spring, wherein the insertion portion inserted into the recess and fixed therein, and wherein the hook portion is hooked to the inner ring. A cable reeling mechanism of a linear drive according to claim 18, wherein the Aufrollrad further comprises an outer wheel which is formed on the outer ring and provided for winding the cable, and wherein the outer wheel comprises a projecting edge which extends from the outer wheel each up and down.

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