DK178946B1 - Safety release mechanism for linear actuator and a linear actuator with a safety release mechanism - Google Patents

Abstract

A safety release mechanism for a linear actuator having a lead screw and a telescopic tube includes a nut, a protection shroud, a sleeve connected to the telescopic tube, a clutching element and a spiral spring. The nut is threadedly and drivingly connected to the lead screw. The protection shroud is fixedly and drivingly connected to one side of the nut. One end of the sleeve is sheathed on the protection shroud while the other end thereof is fixedly connected to the telescopic tube. The outer periphery of the sleeve is formed with notches. The clutching element is sheathed on the sleeve and formed with protrusions configured to be selectively inserted into or removed from the notches. The spiral spring is sheathed on the protection shroud and the clutching element. With this arrangement, cleavage or damage of components can be prevented to thereby increase the safety of operation.

Description

A SAFETY RELEASE MECHANISM FOR A LINEAR ACTUATOR AND A LINEAR ACTUATOR WITH A SAFETY RELEASE MECHANISM

FEEL PIECE INVENTION

The present invention generally relates to actuators, in particular to a linear actuator and its safety release mechanism applied in equipment such as medical instruments, electric chairs, etc.

BACK.GROONO OF THE INVENTION

Linear actuator primarily uses an electric motor and a driving component such as a worm shaft and a worm wheel to drive and rotate a lead screw, while a lead screw is provided for driving a telescopic tube threadedly connected thereon to perform a linear extension or retraction with respect to an outer tube of the telescopic tube. Since the structure, installation and other conditions are simpler and more convenient than those of pneumatic and hydraulic cylinders, the linear actuator is used extensively for equipment such as hospital beds and electric chairs or any other areas requiring extensions and retractions.

[ÖÖÖ3J WO 9830816 Ai discloses a linear actuator which provides an emergency function ensuring that the linear actuator and the carried load arc not damaged by overloading of the actuator, [Ö0G4] For safety purpose, a linear actuator generally comes with limit switches installed in the outer tube and at positions corresponding to inner and outer limit positions of a moving path inside and outside the telescopic tube respectively, such that the limit switches are electrically coupled to the electric motor ibr controlling the QN / OFF of the electric motor and preventing any cleavage or damage to the transmission components caused by improper extension or retraction of telescopic tube. In addition, the limit switches can be installed at starting and ending positions of the path only, so that when the linear actuator is applied to equipment such as an electric chair, there is no safety measure provided at positions other than the starting and ending positions. of the moving path, and children may be damped or injured accidentally by the electric chair, Obviously, the conventional linear actuators require

SUMMARY OF THE INVENTION 10005] Herein, it is a primary objective of the present invention to provide a linear actuator and its safety release mechanism, such that when the telescopic tube is moved outwardly or retracted inwardly to a limited position, a utility can be released from the horizontal movement driven by a lead screw and can be rotated accordingly. The invention not only overcomes the issue of cleavage or damage of transmission components, but also improves the operation safety.

[0006] To achieve the aforementioned objective, the present invention provides a safety release mechanism for a linear actuator, and the linear actuator includes a lead screw and a telescopic tube, and the safety release mechanism comprises a nut, a protection shroud, a telescopic tube sleeve, a clutch element and a spiral springs while the nut is ihreadedly and drivingly coupled to the lead screw; a protection shroud fixedly and drivingly coupled to an edge of the nut; an end of the telescopic tube sleeve is sheathed on another end of the protection shrouded and fixedly coupled to the telescopic tube, and the telescopic tube sleeve includes a plurality of notches formed on an outer periphery of the telescopic tube sleeve; the clutching element is sheathed onto the exterior of the telescopic tube sleeve and includes a plurality of protrusions formed thereon and inserted or detached from the notches respectively; and the spiral spring is sheathed on the protection shroud and the clutching element. If the lead screw is rotated clockwise, then the spiral spring will drive the protection shrouded in a tight binding manner, and the clutch element and the telescopic tube sleeve will be moved linearly together, If the lead screw is rotated counterclockwise and the telescopic tube is blocked, then the protection shroud will be released from being elastically clamped by the spiral spring and rotated together with the nut and the lead screw.

To achieve the aforementioned objective, the present invention provides a linear actuator comprising a driving mechanism, a lead screw, an outer tube, a telescopic tube and a safety release mechanism, the driving mechanism including a holder and an electric motor. mounted on the holder for producing clockwise and counterclockwise rotations; the lead screw is driven by the electric motor to produce rotations; the outer tube is sheathed onto the exterior of the lead screw fixed at an end of the holder, and a stop element installed on the outer tube and at an end away from the holder; the telescopic tube is passed and coupled to the interior of the outer tube and capable of being extended, retracted or moved with respect to the outer tube; the safety release mechanism includes a nut threaded!} 'and drivingly coupled to the lead screw, a protection shroud fixedly coupled to an edge of the nut and linked with the nut, a telescopic tube sleeve with an end sheathed on another end of the protection shrouded and fixedly coupled to the telescopic tube, a clutch element sheathed on the exterior of the telescopic tube sleeve and installed corresponding to the stop element, and a spiral spring sheathed on the protection shroud and the clutching element, wherein the telescopic tube sleeve includes a plurality of notches formed on an outer periphery of the telescopic tube sleeve, and the clutching element includes a plurality of protrusions formed thereon and inserted into ot detached from the notches respectively. If the lead screw is driven by the electric motor to rotate clockwise, the spiral spring will drive the protection shroud, the clutch element and the telescopic tube sleeve to move linearly together in a tight binding manner. When the clutch element is passed through the position of the stop element, the clutch element is pushed away and released from the link relationship with the telescopic tube sleeve, such that the telescopic tube and the telescopic tube sleeve will stop ...... .moving outward.

In addition, the present invention can also omit the limit switches required by the conventional structure to simplify the structure and significantly reduce the component cost. In the path for the telescopic tube to move inwardly into the outer tube, the protection shroud will be pleased with the binding effect of tile spiral spring if the telescopic tube has a resistance (caused by the opposite rotating directions of the protection shroud and the spiral spring) greater than the elastic clamping force (or friction damping) of the protection shroud tightly hounded by the spiral spring. Therefore, the invention can improve the user's safety; greatly and prevent children from being clamped or injured accidentally hv the linear actuator. The spiral spring of the present invention is formed by a plurality of continuous wound rings, and an interval is formed between any two adjacent rings, such that the spiral spring can be extended or contracted axially. Other presently preferred embodiments and further advantages will be apparent from the following detailed description and the dependent claims.

LETTER DESCRIPTION OF THE DRYINGS

[ÖÖ09J FIG. 1 is an exploded view of a safety release mechanism in accordance with the present invention; FIG. 2 is a perspective view of a safety release mechanism in accordance with the present invention; FIG. 3 is a cross-sectional view of a safety release mechanism in accordance with the present invention; FIQi: 4 is an exploded view of a linear actuator in accordance with the present invention; FIG. 5 is a cross-sectional view of asineaP actuator in accordance with present invenfiop; FIG. 6 is a cross-sectional view of a telescopic tube of a linear actuator moved outwardly in an application of the present invention; FIG. 7 is another cross-sectional view of a telescopic tube of a linear actuator moved outwardly in an application of the present invention, FIG. 8 is a cross-sectional view of a telescopic device ...... of a linear "retractor retracted inwardly in an application of the present invention; and [0017] FIG. 9 is another cross-sectional view of a telescopic tube of a linear actuator retracted inwardly in an application of the present invention, DESCRIPTION OF THE PREFERRED EMBODIMENTS; [80 I Sf The technical characteristics and contents of the present invention will become apparent -with the following detailed description accompanied by related drawings, but the drawings are provided for reference find illustration of the invention only, but not intended for limiting the scope of the invention.

With reference to FIGS, f% 3, the present invention provides a linear actuator and its safety release mechanism, and the safety release; Mechanism 1 comprised i nut 10, a protection shroud 20, a telescopic töbë rilëevè 30, d clutching demerit 40 Md and a spiral spring SO.

The nut 10 is made of a plastic material (such as POM) and comprised of a large-diameter cylinder and a small-diameter cylinder extended from an end of the large-diameter cylinder, and the nut 10 is substantially T-shaped. shaped, and a first interna! Thread 11 is formed on the middle section of the β 10, and a first external thread 12 is formed on an external surface of the small-diameter Cylinder.

[0021] The protection shroud 20 is a stair-stepping cylinder comprising a retaining wall 21, a first cylindrical section 22 extended outwardly from the end of the retaining wall 21, and a second cylindrical section 23 exteriorly exteriorly from an end of the first cylindrical section 22, where the protection shroud 20 includes a second internal thread 24 formed at a middle section of the protection shroud 20 and threadedBly coupled to the first external thread: 12.

The telescopic tube sleeve 30 includes a Mitral housing 31 (as shÖWri in FIG. 3} formed at the outer periphery of the second cylindrical section 23, where a convex ring 32 is formed and extended from an external surface at the middle of the telescopic tube sleeve 30, and a plurality of notches 321 are formed at the interval between the convex ring 32 of the telescopic tube sleeve 30; and a second external thread 33 is formed at an edge of the convex ring 32, Clutching element 40 is also a circular cylinder sheathed on the exterior of telescopic tube sleeve 30, and retaining ring 41 ss extended outwardly from an end of clutching element 40, and a plurality of protrusions 42 are extended from an external end surface of the retaining ring 41 and inserted or detached from the notches 321, respectively, The spiral spring 50 of this preferred embodiment is a right-hand spiral spring formed by a plurality of continuously wound rings 51, and one or more intervals 52 are formed between the rings 51, the interval 52 can be formed eoninuously or formed partially, such that the spiral spring 50 can be extended or contracted axially. The spiral spring 50 is coupled to external surfaces of the first cylindrical section 22 of the protection shroud 20 and the clutch element 40 in a circular sheathing manner, and both ends of the spiral spring 50 are abutted between the retaining wail 21 and the retaining ring 41, respectively, such that the elasticity of the spiral spring 50 is provided for pushing the clutch element 40 to move axially in a direction towards the telescopic tube sleeve 30.

[0025] In addition, the safety release mechanism I of the present invention further comprises a limit position cover 60 passed Into the telescopic tube sleeve 30 and ihreadedly coupled to the second internal thread 24 of the protection shroud 20 tor limiting the axial displacement of the telescopic tube sleeve 30. | P026] 'pith reference to FIGS. 4 and § * the present invention provides a linear actuator 8 comprising a driving mechanism 81, a lead screw 82, an outer tube 83, a telescopic tube 84 and the safety release mechanism 1.

[002% The: driving mechanism Si includes a holder 811, an electric motor 812 mounted to the holder 811 for producing a clockwise rotation, a worm shaft 813 extended outwardly Mm the center of the electric motor 812, and a worm wheel 814 contained in the holder 811 and drivingly engaged with the worm shaft 813.

An end of the lead screw 82 is passed into the safety release mechanism 1 and fixedly coupled to the worm wheel 814, and another end; of the lead screw 82 is extended ip a direction away from the holder 811. The lead screw 82 drives the worm shaft 813 by the electric motor 812 and also drives the worm wheel 814 to produce rotations. The external thread of the lead screw 82 is threadedly and drivingly coupled to the first internal thread 11 of the nut 10 (as shown in FIG. 3). In addition, the external thread of the lead screw 82 has the same rotating direction as the spiral spring 50.

[0029] The outer tube 83 is sheathed down the exterior of the lead screw 82 and fixed at an end of the holder 811, and | stop element 831 is Installed inside a space of the outer tube 83 and at a position away from an end of the holder 811, the stop element 831 of this preferred embodiment: is a G-shaped retaining ring, and the stop element 831 is installed corresponding to the clutching elements.

The telescopic tube 84 includes an internal thread formed at an end of the telescopic tube 84 and threadedly coupled to the second external thread 33, and the telescopic 1¾¾ tube 84 is passed and coupled to the interior of the outer tube 83 and can be extended or contracted axially with respect to the outer tube 83. The stop element 831 is generally installed at a maximum limit position of a moving path of moving the telescopic cube 84 outward. In addition, a support 841 is threadedly coupled to an end of the telescopic tube 84 away from the telescopic tubing Sleeve 30 and generally sheathed on a shaft (not shown in the figure) and thus the support 841 cannot produce rotations, reference to FIGS. 6 and 7, the electric motor 812 is provided for driving and rotating the worm shaft 813, such that the worm wheel ..... 814 and the lead screw 82 can b || P! || :: rotated swichronously if the lead screw 82 is rotated clockwise, the support 841 on the fight side of the telescopic title 84 will be moved axially outward by the safety refease mecMnisth 1 arid the telescopic tube 84 which are rotated by the lead screw 82, under the condition that the support 841 is not rotated. Now, the protection shroud 20 and the clutch element 40 are sheathed and linked by the radial contraction of the spiral spring 50. When the safety release mechanism 1 and the telescopic tube 84 are moved continuously outward to a position approaching the limit position (as shown in FIG. 7), the retaining ring 41 of the dlutehibg dement 40 will be pushed away from the telescopic tube sleeve 30 by the stop element 831, so that each protrusion 42 is separated from each notch 121. Under the condition of the lead screw 82 being rotated continuously, the nut 10, the protection shroud 20, the clutch element 40 and the spiral spring 50 will be rotated together with the lead screw 82: in the same direction, and the telescopic tube sleeve 30 and the telescopic tube 84 will be released item the lih |: in relation to the clutching element 40, and thus they will stop moving (or will not move outwardly anymore).

With reference to FIGS. 8 and 9, when the lead screw 82 is rotated in a negative direction (counterclockwise), the safety release mechanism 1 and the telescopic tube 84 will be rotated by the lead screw 82 to perform an axial retraction. together. If a larger resistance is encountered in the path of retracting the telescopic tube 84, the rotating directions of the nut 10 and the protection shroud 20 will be affected by the lead screw 82. If the protection shroud 20 is rotating in a direction opposite to the spiral spring 50, then a section of spiral spring 50 being clamped to the external surface of the protection shroud 20 will be expanded outwardly (as shown in FiG. 9), such that the nut 10 and the protection shroud 20 will be rotated into the same direction as the lead screw 82 (which will produce an idle rotation). Now, the telescopic tube 84 will stop retracting itordiy. When the telescopic tube 84 is retracted at the end of the path, an object (not shown in the figure) coupled to the support 841 has been abutted or stacked already, so that the retraction of the telescopic tube 84 will receive a greater resistance. Similarly, the telescopic tube 84 miles stop 'retracting inwardly.

[0033] In summary of the description above, the linear actuator and its safety release mechanism of the present invention achieve the expected effects and overcome the prior art shortcomings, and complies with the patent: application requirements, and thus is duly filed. for patent application, While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.

Claims (14)

SSKK | RiEDSFRSG0I ^ ELSESMEKmNSS «E TO L§E / IS ACTUATOR ÖÉ EN LINE / IS ACTUATOR WITH IS SAFETY RELEASE SEMEKA» NISME Pateilt Requirements 1, the safety figure travel mechanisms (1) for a linear actuator (8), wherein the inner actuator (8) carried an idler screw (82) and a teescopic tube (84), and the safety detecting mechanism (1 j includes: one m africa (10) ) which is fitted to the salads so that the thread is measured in terms of dnv and in the cube of the guide screw (82): a protective cap | 2ö) which is fixed and propellant-like cob t1! an edge of the motor drum (10); a teescopic rudder sleeve (30) having one end which is encapsulated on the protective sheath (10) and another end which is adapted to be attached to the teescopic tube (84) and having a plurality of notches (321) format on an outer periphery of the teiscopic sleeve sleeve (30); a coupling element (40) which is encased on the teescopic tube sleeve (30) and having a plurality of projections (42) formed on the coupling element (40) and selectively inserted into the cup from the iris notches (321), and a coil spring (50) encased on the protective sheath (20) and the coupling element (40); thereby rotating the spiral spring (50), rotating the guide screw (82) clockwise, to drive the protective sleeve (20) in a tethered manner, and the coupling element (40) and the teescopic rudder sleeve (30) moving unevenly: together and if the guide screw (82) ) is rotated counterclockwise and the latching tube (84) beeped, then the protective sheath (20) will be released from being resiliently clamped by the coil spring (50), and the protective sheath (20) will be rotated together with the guide screw (82). 2, Secure release mechanism (1) for the linear actuator (8) according to claim 1, wherein the nut (10) includes a first external thread (12) formed on an outer periphery of one end of the metric (10) and the protective cap (20). ) includes a second internal thread (24) formed in a mid section of the protective sheath (20) and threadedly the cube to the outermost external thread (12). 3, Safety release mechanism (1) for the liner actuator (8) according to claim 1, wherein the protective cap (20) includes a solid high-pressure sieve (21), a first cylindrical section (22) extending outwardly from an end of the sealing wall (21), and a second cylindrical section (23) extending outwardly from an end of the farthest cylindrical section (22): and the telescoping tube sleeve (30) is the end cap of an outer bead of the second cylindrical section (23), and one end of the coil spring (50) second from the coupling element (40) is encased on an outer pen spring in the first cylindrical section (22). A safety release mechanism (1) for the inner actuator (8) according to claim 3, wherein the telescopic rudder sleeve (30) includes a convex ring (32) which is shaped oak extending from an outer face of the convex ring (32). and the inboxes (321) are formed in the lumen spaces of the convex members (32), and a phasoidal annulus (41) extends outwardly from one end of the coupling element (40), and the projections (42) extend from an outer end face of retaining rings ( 41 | and are respectively seated into or cabled from the notches (321). The safety release mechanism (1) of the linear actuator (8) according to claim 4, wherein the coil spring (50) includes both ends abutting the retaining wall (21) of the actuator, respectively. the protective sheath (20) and the retaining ring (41) of the coupling element (40). A safety routing mechanism (1) for the linear actuator (8) according to claim 1 ..... wherein the coil spring (50) rotates in the same direction of the guide screw (82). 7. Safety release mechanism (1) for the linear actuator (8) according to claim 8, wherein the coil spring (50) maintains at least one fastener (52) formed between the plurality of continuous wound rings (51), 8 Safety Finger Riser (1) for that lineage. 8) according to claim 1, further comprising a restriction position cover (60) which is driven into the thiescopic frame sleeve (30) and firmly coupled to the protective sheath (20) 1 limiting an axial displacement of the telescopic frame sleeve (30). . 9. Lines acluator (8), comprising: a drive mechanism (81 j * containing a holder (§11) and a non-circular motor (812) mounted on the bolt (811) for producing clockwise rotations) and a guide screw (82) driven by the electric motor (812) to produce a nation; an extender (88) encased on the exterior of the guide screw (82) and secured at one end by the bolt (811) and has a stop element (831) installed on the outer bar (83) and at an end away from the bolt (811); a telescopic fir (84) which is fast and coupled to it exterior tubes (83) which can be extended or retracted in relation to the outer tubes (83); and a safety release mechanism (1) comprising a nut (10) threaded massively and propulsively coupled to the guide screw (82) a protective sheath (20) firmly and propulsively coupled to an edge of the mold (10); a telescopic frame sleeve (30) with an end encased on the b the sheath cap (28) and another end which is phased to the telescopic tube (84); a coupling element (40) encased on the telescopic tube sleeve (30) and installed corresponding to the stop element (831); a coil spring (50) encased on! the protective sheath (20) and the coupling element (40), and having a plurality of notches (321) formed on an outer periphery of the teescopic frame sleeve (30), and the coupling element (40) carried a plurality of projections (42), formed therefrom and respectively inserted into eli coupled from the inboxes (321); thereby, if the guide screw (82) is rotated clockwise, the coil spring (50) will drive the protective cap (20) in a binding manner to drive the protective cap (20), the coupling element (40) and the teescopic ridge sleeve (30) for irrigation together, and if the coupling element (40) passes through a position of the stop element (831) and is blocked, the coupling element (40) will be pushed away to release the connection relation time with the telescopic sleeve (30), all the telescopic γθγ (84) is sealed. and the telescopic rudder sleeve (3Θ) will stop looking outward. A linear actuator (8) according to claim 9; wherein the die (10) includes a first outer thread (12) formed on an outer periphery of one end of the die (10) and the protective cap (20) contains a second inner thread (24) which is molded! in a middle portion of the protective cap (20) and threadedly coupled to the first external thread (12). The linear actuator (8) of claim 9, wherein the protective cap (20), a retaining wall (21), a first cylindrical section (22) extend outwardly from one end of the retaining wall (21), and a second cylindrical section (23). extends outwardly from one end of the first cylindrical section (22) and the telescopic rudder sleeve (30) is enclosed on an outer periphery of the second cylindrical section (23) and one end of the coil spring (50) away from the coupling element (4Θ) is encased on an outer periphery of the first cylindrical section (22). The uneser actuator (8) of claim 11, wherein the telescopic tube sleeve (30) contains a convex ring "formed and extending from an outer face of the convex ring (32) and the notches (321) are shaped in the space between the convex rings (32) and a fixed ring ring (41) extending outwardly from one end of the coupling element (40), and projections extending from an outer distal face of the retaining ring (41) and respectively being inserted into the owns the cube from the notches (321), A linear actuator (8) according to claim 12, wherein the coil spring (50) has hook ends which are in contact with the retaining wall (21) of respectively. the protective cap (20) and the retaining ring (41) of the coupling element (40). The uneser actuator (8) according to claim 9, wherein the coil spring (50) rotates in the crippled direction of the sediment screw (82). A linear actuator (8) according to claim 14, wherein the coil spring (50) comprises at the center a gap formed between the plurality of continuously wound rings (51). The linear actuator (8) of claim 9, wherein the safety release mechanism (1) further comprises a gasket position cover (80) which is fastly inserted into the tetescopic rudder sleeve (30) and firmly coupled to the protective cap (20) for limiting operation. a shaft displacement of the tetescopic sleeve (30).