TWI403653B - Linear actuator and safety release mechanism for the same - Google Patents

Abstract

The present invention relates to a safety release mechanism for a linear actuator. The linear actuator has a lead screw and a telescopic tube. The safety release mechanism includes a nut, a protection shroud, a sleeve, and a torsion 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. The outer periphery of the protection shroud is formed with protrusions. The sleeve is sheathed on the protection shroud and fixedly connected to the telescopic tube. The outer periphery of the sleeve is formed with notches for allowing the protrusions to be inserted therein. The torsion spring is sheathed on the protection shroud and the sleeve. When the lead screw rotates, the protrusions of the protection shroud are engaged within the notches of the sleeve to rotate together. When the telescopic tube is pulled by an external force, the protrusions are removed from the notches, so that the protection shroud and the nut can freely rotate with respect to the sleeve. By interrupting the retraction of the telescopic tube, the safety during the operation of the linear actuator is increased.

Description

Linear actuator and its safety release mechanism

The present invention relates to an actuator, and more particularly to a linear actuator for a medical device, a power chair or the like and a safety release mechanism thereof.

The Linear Actuator mainly uses a motor, a worm, a worm wheel, and the like to drive a lead screw to rotate, and at the same time, the telescopic tube screwed thereto by the lead screw is opposite to the outside of the telescopic tube. The linear extension or retraction of the tube is widely used in medical equipment or equipment such as hospital beds and electric chairs because of its simple structure and installation, such as its structure and installation. Or other fields that need to be stretched or contracted.

In general, linear actuators are equipped with limit switches inside the outer tube and corresponding to the first and last limit positions of the telescopic tube movement stroke, in order to utilize the electrical properties of the limit switches and the electric motor. The connection controls the start or stop of the motor, so that the telescopic tube is not excessively extended or retracted to cause cracking or damage of the transmission element.

However, the setting positions of these limit switches can only be installed at the first and end of the moving stroke. When applied to equipment such as electric chairs, they do not have any safety precautions due to other positions in the moving stroke. There have been unfortunate incidents in which children have been accidentally pinched or pinched off by equipment such as electric chairs; there is a real need for improvement.

It is an object of the present invention to provide a linear actuator and a safety release mechanism thereof that can cause a nut and a nut sheath to be opposite to a telescopic tube sleeve when an obstruction is encountered during the inward retraction of the telescoping tube The idling is generated to interrupt the movement of the telescopic tube to continuously retract inward, thereby improving the safety of use.

In order to achieve the above object, the present invention provides a safety release mechanism for a linear actuator having a lead screw and a telescopic tube, the safety release mechanism including a nut, a nut sheath, and a a telescopic tube sleeve and a torsion spring, the nut and the lead screw are screwed together; the nut sheath is fixed on one side of the nut and interlocked with each other, and the outer periphery of the nut sheath is formed a plurality of bumps; the other end of the telescopic tube sleeve is sleeved to the other end of the nut sheath, and is fixed to the telescopic tube, and is disposed at the outer periphery of the telescopic tube sleeve to be embedded or disengaged from the protrusions a plurality of interlocking cavities; the torsion spring is coupled to the outer surface of the nut sheath and the telescopic tube sleeve in an annular manner; wherein the nut sheath and the telescopic tube sleeve are Inserting the bumps into the slots to move linearly together; when the sleeve of the bellows is blocked and stops moving, the bumps are detached from the slots, and the nut sheath and the nut are The nut is free to rotate relative to the telescoping tube sleeve.

In order to achieve the above object, the present invention provides a linear actuator including a driving mechanism, a lead screw, an outer tube, a telescopic tube and a safety release mechanism. The driving mechanism includes a base and is fixed to the machine. a motor that can generate a positive and negative rotation; the lead screw is driven to rotate by the motor; the outer tube is sleeved outside the lead screw and fixed to one end of the base; the telescopic tube is connected inside the outer tube And a telescopic movement relative to the screw; the safety release mechanism includes a nut that is screwed to the lead screw, a nut sheath fixed to one side of the nut and interlocked with each other, and one end of the screw a telescopic tube sleeve fixed to the telescopic tube at the other end of the cap sheath, and a torsion spring coupled to the nut sheath and the telescopic tube sleeve, the outer periphery of the nut sheath is formed with a plurality of bumps The outer circumference of the telescopic tube sleeve is provided with a plurality of slots embedded or detached from the protrusions; wherein when the lead screw is driven by the motor to rotate, the nut sheath and the extension tube sleeve are Embedding the embedding with the bumps And linearly moving together; when the telescopic tube is subjected to tension, the protrusions are detached from the slots, so that the lead screw, the nut sheath and the nut are together with respect to the telescopic sleeve The cylinder is free to rotate.

The invention also has the following effects: in the stroke of the telescopic tube moving inwardly into the inner tube, if the movement of the telescopic tube is blocked, the nut sheath and the telescopic tube sleeve can be disconnected, thereby greatly improving the user. The safety of use and the effective suppression of unfortunate incidents in which children are pinched or pinched. When the nut spring is reversely rotated, the torsion spring provides a pre-twisting manner to provide alignment of each of the projections of the nut sheath with the respective slots of the telescopic tube sleeve. The guiding ring provides support for the nut sheath and the nut, so that the outer tube can be made into tubes of various cross-sectional shapes according to actual use requirements; and the soft joint of the safety release mechanism and the outer tube can be provided. , while reducing the noise when operating.

The detailed description and technical content of the present invention are set forth in the accompanying drawings.

Referring to the first, second and third figures, the present invention provides a linear actuator and a safety release mechanism thereof. The safety release mechanism 1 mainly comprises a nut 10, a nut sheath 20 and a telescopic sleeve. The barrel 30 and a torsion spring 40.

The nut 10 can be made of a plastic material (such as POM), which is composed of a large diameter cylindrical column 11 and a small diameter cylindrical column 12 extending from one end of the large diameter cylindrical column 11 and is substantially one. In the shape of a "convex", the central portion of the nut 10 is provided with a first internal thread 13 and a first external thread 14 is formed on the outer surface of the small-diameter cylindrical column 12.

The nut sheath 20 is a stepped cylindrical column mainly composed of a first cylindrical section 21 and a second cylindrical section 22 extending outward from one end of the first cylindrical section 21, and the first cylindrical section 21 is outside. The rim is larger than the outer diameter of the second cylindrical section 22, and a accommodating groove 211 is formed outside the first cylindrical section 21, and a retaining ring 212 is formed on each side of the accommodating groove 211. Further, a plurality of bumps 23 are formed at intervals where the first cylindrical section 21 and the second cylindrical section 22 meet. Furthermore, a second internal thread 24 is integrally provided with the first external thread 14 in a central portion of the nut sheath 20.

The telescopic tube sleeve 30 has a central hole 31 that is sleeved on the outer circumference of the second cylindrical section 22 so that the telescopic tube sleeve 30 can freely rotate relative to the nut sheath 20, where the extension tube sleeve 30 is close to One end of the nut sheath 20 is provided with a plurality of cavities 32 which are embedded or detached from each other, and a convex ring 33 is formed on the outer surface of one side of the cavities 32; A second external thread 34 is formed on the telescopic tube sleeve 30 on one side of the convex ring 33.

The torsion spring 40 of the present embodiment is a right-handed torsion spring, which is coupled to the outer surface of the first cylindrical section 22 and the telescopic tube sleeve 30 of the nut sheath 20 in an annular tight-fitting manner, and the two end faces thereof respectively The retaining ring 212 and the convex ring 33 abut against each other. When the nut sheath 20 rotates in the forward direction, the torsion spring 40 provides a rotational driving of the nut sheath 20 and the telescopic tube sleeve 30 in a tightening manner; When the nut sheath 20 is rotated in the reverse direction, the protrusions 23 of the nut sheath 20 are pre-twisted to align with the respective slots 32 of the telescopic tube sleeve 30, that is, in the telescopic tube. After the sleeve 30 is rotated relative to the nut sheath 20, the corresponding fitting of each of the projections 23 and the respective grooves 32 can be ensured.

Further, the safety release mechanism 1 of the present invention further includes a guiding ring 50 which is substantially in the shape of a "C". The guiding ring 50 is sleeved in the receiving groove 211 of the nut sheath 20, thereby providing The nut sheath 20 and the nut 10 are supported, and the nut sheath 20 and the nut 10 are free to rotate relative to the guide ring 50. Further, on the outer peripheral surface of the guide ring 50, a plurality of blocks 51 arranged at intervals are protruded.

Furthermore, the safety release mechanism 1 of the present invention further includes a limiting member 60 that penetrates into the interior of the telescopic tube sleeve 30 to be screwed to the second internal thread 24 of the nut sheath 20. The amount of axial displacement of the telescopic tube sleeve 30 is limited.

Referring to Figures 4-6, the present invention provides a linear actuator that mainly includes a driving mechanism 81, a lead screw 82, an outer tube 83, a telescopic tube 84, and the foregoing safety. Release mechanism 1.

The driving mechanism 81 includes a base 811, a motor 812 fixed to the base 811 and capable of generating a forward and reverse rotation, a worm 813 extending outward from the center of the motor 812, and being housed inside the base 811 and coupled to the worm 813. A worm gear 814 that meshes with the transmission.

One end of the lead screw 82 is connected to the safety release mechanism 1 and fixed in the worm wheel 814, and the other end extends away from the base 811. The lead screw 82 drives the worm 813 by the motor 812 and drives the worm wheel 814. The rotation action is generated, and the external thread of the lead screw 82 is screwed to the first internal thread 13 (shown in the third figure) of the nut 10 described above. Further, the external thread of the lead screw 82 is rotated in the same direction as the aforementioned torsion spring 40.

The outer tube 83 is sleeved on the outside of the lead screw 82 and fixed to one end of the base 811. The inner tube 83 is provided with a plurality of grooves 831 in which the insert blocks 51 of the guide ring 50 are fitted to each other (as shown in the sixth figure). That is shown so that the guide ring 50 can only move linearly along the axial direction of the outer tube 83.

One end of the telescopic tube 84 is provided with an internal thread (shown in FIG. 7 ) which is screwed to the second external thread 34 . The telescopic tube 84 is connected to the inside of the outer tube 83 and can be axially opposite to the outer tube 83 . Extending or retracting movement; another end of the telescopic tube 84 away from the end of the telescopic tube sleeve 30 is screwed with a seat 841. The holder 841 is generally sleeved on a shaft (not shown) without rotation.

In addition, the linear actuator 8 of the present invention further includes two limit switches 85 which are respectively disposed inside the outer tube 83 and electrically connected to the motor 812, and corresponding to the first end and the end of the movement of the safety release mechanism 1 The position is installed so that the second limit switch 85 is pressed by the first end chamfered portion of the large-diameter cylindrical column 11 of the nut 10, and the motor 812 is stopped.

Referring to the seventh figure, in use, the worm 813 is rotated by the motor 812, and the worm wheel 814 and the lead screw 82 can be driven to rotate synchronously (refer to the fourth figure), and the lead screw 82 is rotated in the forward direction (clockwise direction). When rotating, and the support 841 on the right side of the telescopic tube 84 is fixed without rotating, the respective projections 23 of the nut sheath 20 are respectively inserted into the respective cavities 32 of the telescopic tube sleeve 30, and the torque is generated. The spring 40 provides an auxiliary combination of the nut sheath 20 and the telescopic tube sleeve 30 in an annular tightening manner, so that the safety release mechanism 1 and the telescopic tube 84 can be axially removed together by the rotation of the lead screw 82; When the large-diameter cylindrical column 11 of the nut 10 is moved to the position of the outer limit switch 85, the limit switch 85 is touched by the inclined surface of the chamfered portion (see FIG. 8), and the motor 812 is The driving action is interrupted, and at this time, the telescopic tube 84 is no longer continued to extend outward.

Referring to FIGS. 8 and 9, when the lead screw 82 is rotated in the reverse direction (counterclockwise rotation), the safety release mechanism 1 and the telescopic tube 84 are axially retracted together by the rotation of the lead screw 82 ( As shown in the eighth figure); when the tension (the obstruction or blocking) is received during the retraction of the telescopic tube 84, the telescopic tube sleeve 30 will be pinched by the telescopic tube 84 to stop moving, but the nut 10 and the nut The sheath 20 is continuously rotated by the lead screw 82, and the respective protrusions 23 are disengaged from the interlocking relationship with the respective slots 32. After the nut sheath 20 is disengaged from the telescopic tube sleeve 30, the nut 10 and the screw are screwed. The cap sheath 20 will rotate together (ie, idle) following the rotation of the lead screw 82 (as shown in FIG. 9), and since the telescoping tube sleeve 30 is stationary, and due to the direction of rotation of the torsion spring 40 and the lead screw 82 The direction of rotation is reversed, and the torsion spring 40 does not impose a constraint on the nut sheath 20 and the telescoping tube sleeve 30, so that the nut 10 and the nut sheath 20 can be in the telescopic tube sleeve 30 and the guide ring 50. The inter-turn is free to rotate, which in turn enables the telescoping tube 84 to stop moving inwardly.

Referring to the tenth figure, the safety release mechanism of the present invention may be the same as the above-mentioned embodiment, and may also be of the present embodiment, the first cylindrical section 21' of the nut sheath 20' of the safety release mechanism 1'. It is assembled with an outer tube (not shown) having a circular inner hole, so that the outer circumference of the first cylindrical section 21' is supported by the inner wall of the outer tube, and when the stroke of the telescopic tube 84 is retracted, the stroke is blocked. The nut sheath 20 is freely rotatable between the telescoping tube sleeve 30 and the inner wall of the outer tube, thereby enabling the telescoping tube 84 to stop retracting inwardly.

In summary, the linear actuator and the safety release mechanism thereof of the present invention can achieve the intended use purpose, and solve the lack of the prior art, and because of the novelty and the progressiveness, fully comply with the requirements of the invention patent application, and convert If the patent law is filed, please check and grant the patent in this case to protect the rights of the inventor.

1, 1'‧‧‧Safety release agencies

10‧‧‧ nuts

11‧‧‧ Large diameter cylindrical column

12‧‧‧Small diameter cylindrical column

13‧‧‧First internal thread

14‧‧‧First external thread

20, 20'‧‧‧ nut jacket

21, 21’‧‧‧ first cylindrical section

211‧‧‧ accommodating slots

212‧‧ ‧ retaining ring

22‧‧‧Second cylindrical section

23‧‧‧Bumps

24‧‧‧Second internal thread

30‧‧‧ Telescopic tube sleeve

31‧‧‧ center hole

32‧‧‧Inlay

33‧‧‧ convex ring

34‧‧‧Second external thread

40‧‧‧Torque spring

50‧‧‧ Guide ring

51‧‧‧Block

60‧‧‧Limited parts

8‧‧‧Linear actuator

81‧‧‧ drive mechanism

811‧‧‧ machine base

812‧‧‧Electric motor

813‧‧‧ worm

814‧‧‧ worm gear

82‧‧‧ lead screw

83‧‧‧External management

831‧‧‧ trench

84‧‧‧ telescopic tube

841‧‧‧Support

85‧‧‧limit switch

The first figure is an exploded perspective view of the safety release mechanism of the present invention.

The second figure is an appearance view of the combination of the safety release mechanism of the present invention.

The third figure is a sectional view of the combination of the safety release mechanism of the present invention.

The fourth figure is an exploded perspective view of the linear actuator of the present invention.

Fig. 5 is a perspective view showing the combination of the linear actuator of the present invention.

Figure 6 is a cross-sectional view showing the combination of the safety release mechanism and the outer tube of the present invention.

Figure 7 is a cross-sectional view showing the state in which the telescopic tube of the linear actuator of the present invention is moved outward.

Figure 8 is a cross-sectional view (I) of the telescopic tube of the linear actuator of the present invention inwardly retracted into use.

Figure 9 is a cross-sectional view (II) of the telescopic tube of the linear actuator of the present invention inwardly retracted into use.

Figure 11 is a perspective exploded view of another embodiment of the safety release mechanism of the present invention.

1‧‧‧Safe release mechanism

10‧‧‧ nuts

11‧‧‧ Large diameter cylindrical column

12‧‧‧Small diameter cylindrical column

13‧‧‧First internal thread

14‧‧‧First external thread

20‧‧‧ Nut Jacket

21‧‧‧First cylindrical section

211‧‧‧ accommodating slots

212‧‧ ‧ retaining ring

22‧‧‧Second cylindrical section

23‧‧‧Bumps

24‧‧‧Second internal thread

30‧‧‧ Telescopic tube sleeve

31‧‧‧ center hole

32‧‧‧Inlay

33‧‧‧ convex ring

34‧‧‧Second external thread

40‧‧‧Torque spring

50‧‧‧ Guide ring

51‧‧‧Block

60‧‧‧Limited parts

Claims (14)

A safety release mechanism for a linear actuator, the linear actuator having a lead screw and a telescopic tube, the safety release mechanism comprising:
a nut that is screwed to the lead screw;
a nut sheath is fixed to one side of the nut and interlocked with each other, and the outer periphery of the nut sheath is formed with a plurality of bumps;
a telescopic tube sleeve having one end sleeved to the other end of the nut sheath and fixed to the telescopic tube, and at the outer circumference of the telescopic tube sleeve is provided with a plurality of interlocking or decoupling with the protrusions a slotted groove; and a torsion spring coupled to the outer surface of the nut sleeve and the telescopic tube sleeve in an annular manner;
When the lead screw rotates, the nut sheath and the telescopic tube sleeve are linearly moved together by the protrusions embedded in the slots; when the telescopic tube sleeve is blocked and stops moving, the protrusions The block is disengaged from the slots to freely rotate the nut guard and the nut relative to the telescoping tube sleeve. The safety release mechanism of the linear actuator of claim 1, wherein the torsion spring has the same direction of rotation as the lead screw. The safety release mechanism of the linear actuator of claim 1, wherein the outer circumference of one side of the nut is formed with a first external thread, and the first external thread is provided at a central portion of the nut sheath. a second internal thread that is screwed to each other. The safety release mechanism of the linear actuator of claim 1, wherein the nut sheath comprises a first cylindrical section and a second cylindrical section extending outward from an end of the first cylindrical section, the second cylinder The segment is connected to the telescopic tube sleeve. The safety release mechanism of the linear actuator of claim 4, further comprising a guiding ring, the receiving portion of the first cylindrical section being provided with a receiving groove for the guiding ring to be sleeved. The safety release mechanism of the linear actuator of claim 5, wherein the guide ring has a "C" shape. The safety release mechanism of the linear actuator of claim 1, further comprising a limiting member, the limiting member and the nut sheath are fixed to each other to limit the axial displacement of the telescopic tube sleeve . A linear actuator comprising:
a driving mechanism comprising a base and an electric motor fixed to the base and capable of generating a forward and reverse rotation;
a lead screw driven by the motor to rotate;
An outer tube is sleeved on the outside of the lead screw and fixed at one end of the base;
a telescopic tube that is threaded inside the outer tube and capable of telescopic movement relative thereto; and a safety release mechanism including a nut that is screwed with the lead screw, fixed to one side of the nut and mutually a linked nut sheath, a telescopic tube sleeve at one end of the nut sheath and the other end of the nut sheath fixed to the telescopic tube, and a torsion spring coupled to the nut sheath and the telescopic tube sleeve a plurality of protrusions are formed on the outer circumference of the nut sheath, and the outer circumference of the sleeve of the sleeve is provided with a plurality of slots embedded or detached from the protrusions;
When the lead screw is rotated by the motor, the nut sheath and the telescopic tube sleeve are linearly moved together by the protrusions embedded in the slots; when the extension tube is subjected to a tensile force, the protrusions The block is disengaged from the slots such that the lead screw, the nut guard and the nut are free to rotate with respect to the telescoping tube sleeve. The linear actuator of claim 8, wherein the torsion spring has the same direction of rotation as the lead screw. The linear actuator of claim 8, wherein a peripheral edge of one side of the nut is formed with a first external thread, and a central portion of the nut sheath is screwed to the first external thread. a second internal thread. The linear actuator of claim 8, wherein the nut sheath comprises a first cylindrical section and a second cylindrical section extending outward from an end of the first cylindrical section, the second cylindrical section being for the Telescopic tube sleeve sleeve connection. The linear actuator of claim 11, further comprising a "C" shaped guide ring, the outer portion of the first cylindrical section being provided with a receiving groove for the guiding ring to be sleeved. The linear actuator of claim 12, wherein the outer peripheral surface of the guide ring protrudes with a plurality of spacers disposed at intervals, and the outer tube is internally provided with a plurality of grooves that are fitted to the inserts so that The guide ring can only move linearly along the axis of the outer tube. The linear actuator of claim 8, further comprising a limiting member fixed to the nut sheath to limit an axial displacement of the telescopic tube sleeve.