JP2012207798A - Actuator with built-in load sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of load sensors for detecting a floor load of a bed, the load sensor being provided separately from the bed or installed outside the bed.SOLUTION: In the actuator, one end side of a screw shaft 1 is rotatably supported by a base body 2, a female threaded member 3 is engaged with the screw shaft, and an actuation rod body 4 fixed to the female threaded member is configured to advance and retreat in the axial direction of the screw shaft. An operation tube body 8 that receives a load transmitted from the screw shaft is provided in the base body. The base body is detachably attached with a support member 8 on the opposite side of the screw shaft side. In the support member, a detecting tube body 9 is formed in a projecting manner, which is brought into contact with the operation tube body when attached to the base body, and a strain gauge 10 is attached to the outer surface of the detecting tube body. The various actuators having different load ranges can be easily constituted.

Description

  The present invention relates to a load sensor built-in actuator.

  An actuator configured to rotatably support one end side of the screw shaft on the base body, and to engage the female screw member with the screw shaft and to move the operating rod body fixed to the female screw member in the axial direction of the screw shaft is a bed or the like. It is widely used in the floor lifting mechanism and so on.

  On the other hand, recently, for example, as disclosed in Patent Document 1, load sensors are installed on all the legs of the bed so that the load on the floor can be detected, thereby detecting the patient's weight and patient's movement. It is used for nursing care and nursing. For example, the occurrence of an accident or the like can be prevented by detecting and reporting that the user of the bed such as an elderly person has descended from the floor by measuring the load.

  There are various means for detecting the load on the floor, such as a means for detecting a change in the pressure in the mood caused by the load.

JP-A-11-342160

When the load sensor is configured separately from the bed as in Patent Document 1, and installed outside, there are the following problems.
1. Since the load sensor and the cable from the load sensor are exposed on the floor of the hospital room, it is difficult to ensure environmental resistance such as waterproofness, dustproofness, impact resistance, and vibration resistance in the usage environment.
2. When moving the bed, the load sensor must be removed one by one, which is very troublesome.
3. Many types of actuators with different load ranges cannot be easily configured.
Therefore, the present invention aims to solve such problems.

  In the present invention, in order to achieve the above-mentioned object, one end side of the screw shaft is rotatably supported on the base, and an operating screw body fixed to the female screw member is screwed into the female screw member. In an actuator configured to be capable of moving back and forth in the axial direction, an operating cylinder for transmitting a load from the screw shaft is provided on the base, and a support member can be attached to and detached from the base on the side opposite to the screw shaft side. A load sensor built-in actuator, in which a detection cylinder that abuts against the operating cylinder when mounted on the base is provided on the support member, and a strain gauge is attached to the outer surface of the detection cylinder. Propose.

  According to the present invention, in the above-described configuration, a plurality of support members having different load ranges of the detection cylinder and the strain gauge are configured, and the measurement load range can be changed by a support member selected from these and mounted on the base. A load sensor built-in actuator is proposed.

  Further, the present invention proposes an actuator with a built-in load sensor that can measure a load on the floor by using it as an actuator of an elevating mechanism for the bed floor in the above configuration.

  In the actuator of the present invention, when the support member is mounted on the base, the detection cylinder is disposed between the operation cylinder and the support member, so that the detection cylinder is axially moved by a load transmitted from the screw shaft to the operation cylinder. And is elastically deformed so that the middle part swells like a drum. Since the strain gauge is deformed corresponding to the elastic deformation, the load transmitted from the screw shaft to the working cylinder can be measured corresponding to the deformation amount of the strain gauge.

  As described above, the actuator with a built-in load sensor according to the present invention can be used for a bed raising / lowering mechanism or the like having the same configuration as a conventional actuator, including the outer shape, except that the load sensor is built in the base. In this case, the load on the bed can be measured as a structure integrated with the bed.

  The strain gauge detection signal built in the actuator can be derived to the outside of the actuator via an electric wire via detection means such as an amplifier, or can be derived to the outside of the actuator via wireless communication and connected to the load measuring means.

  Thus, when the bed is configured using the present invention, the load sensor and the cable from the load sensor are not exposed on the floor of the hospital room, so that the waterproof, dustproof, impact resistance, vibration resistance, etc. It is easy to ensure high environmental resistance.

  Also, when moving the bed, the troublesome work of removing the load sensors one by one is unnecessary.

  Further, in the load sensor built-in actuator according to the present invention, since the load sensor and the actuator are integrally formed, the systematic adjustment of the load sensor can be performed at the time of manufacturing the load sensor built-in actuator itself, Since calibration at the time of installation becomes unnecessary, it is possible to reduce the assembly process of the bed and the like and to reduce the cost.

  In the actuator of the present invention, in particular, since the support member can be attached to and detached from the base, if a plurality of support members having different load ranges of the detection cylinder and the strain gauge are configured, the support member can be selected from these and attached to the base. The measurement load range of the actuator can be changed by the mounted support member, and various types of actuators having different load ranges can be easily configured by exchanging the support member.

  In the actuator with a built-in load sensor according to the present invention, a support member having a structure in which a supporting rib is projected instead of the detection cylinder is mounted on the base instead, so that the load sensor is not built in with the same outer shape. The actuator can be easily configured.

It is explanatory vertical section showing an embodiment of an actuator with a built-in load sensor of the present invention. FIG. 2 is an explanatory longitudinal sectional view showing a state where a support member is removed from the actuator of FIG. 1. FIG. 6 is an explanatory longitudinal sectional view showing another support member that can be mounted on a base in the actuator of FIG. 1. FIG. 3 is an explanatory longitudinal sectional view showing a state where another support member is mounted on a base in the actuator of FIG. 1.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 4 are longitudinal sectional views showing an embodiment of an actuator with a built-in load sensor according to the present invention.
Reference numeral 1 denotes a screw shaft. One end of the screw shaft 1 is rotatably supported by the base 2 and a female screw member 3 is screwed onto the screw shaft 1, and the operating rod body 4 is engaged with the female screw member 3. And the actuating rod 4 is configured to be able to advance and retreat in the axial direction of the screw shaft 1. The base body 2 is hatched in the figure, but the hatched portion does not necessarily indicate a non-empty portion, and a space portion can be appropriately configured. Although not shown, a radial bearing that is constrained only in the radial direction and can be rotated between the base 2 and the screw shaft 1 can be provided at an appropriate position.

  Next, reference numeral 5 denotes a small diameter portion provided on one end side of the screw shaft 1. A thrust bearing 6 is arranged on the small diameter portion 5, and the load on the screw shaft 1 is applied to the upper side of the small diameter portion 5. It is set as the structure transmitted to the upper side member of the thrust bearing 6 by a step part. An operating cylinder 7 is provided below the lower member of the thrust bearing 6. The thrust bearing 6 and the actuating cylinder 7 are coaxially disposed outside the screw shaft 1.

  Reference numeral 8 denotes a support member, and the support member 8 is configured to be attachable to the rear side of the base 2 as shown in FIGS. The mounting mechanism is appropriate, for example, a structure that is coupled by a fastening member such as a screw or a structure that is coupled by screwing.

  Next, a detection cylinder 9 protrudes from the support member 8, and at the time of mounting shown in FIG. 1, the detection cylinder 9 is coaxially disposed outside the screw shaft 1, and its tip surface is the working cylinder 7. It is in contact with the lower surface.

  A strain gauge 10 is attached to the outer surface of the detection cylinder 9. Reference numeral 11 denotes a circuit board. A signal wire 12 from the strain gauge 10 is connected to the circuit board 11 and a detection means for amplifying a detection signal of the strain gauge 10 is configured as one of the functions. The output wire 13 from the circuit board 11 is led out of the base body 1 from the lead-out portion having the cord cap 14, and connected to a controller 15 having the load measuring means as a part of the function. The controller 15 and the circuit board 11 can have functions related to motor drive control and rotation amount detection, which are not shown, in addition to the load detection function related to the strain gauge 10 described above. The circuit board 11 can be omitted by providing the controller 15 with the function.

  As described above, in the present invention, the detection cylinder 9 to which the strain gauge 10 is attached, and the operation cylinder 7 and the thrust bearing 6 that transmit the load to the detection cylinder 9 are configured coaxially with respect to the screw shaft 1. It can be stored in a compact.

  Therefore, the actuator with a built-in load sensor according to the present invention can be configured in the same manner as a conventional actuator, including the outer shape, except that the load sensor is built in the base body 2. It can be used for a lifting mechanism such as.

  That is, in this case, the load transmitted from the actuating rod 4 to the screw shaft 1 via the female thread member 3 is transmitted to the actuating cylinder 7 via the thrust bearing 6, and between the actuating cylinder 7 and the support member 8. The arranged detection cylinder 9 is compressed in the axial direction of the screw shaft 1.

  The detection cylinder 9 compressed in the axial direction undergoes elastic deformation such that the middle portion swells like a drum, and the strain gauge 10 deforms in response to this elastic deformation. Correspondingly, the load applied via the actuating rod 4, that is, in the case of this embodiment, the load from the floor of the bed is transferred to the controller outside the actuator via the circuit board 11 and the output electric wire 13. 15 can be measured.

  In the above embodiment, the detection signal from the strain gauge 10 incorporated in the actuator is led out of the actuator by the output electric wire 13 through the lead-out part having the cord cap 14, and this lead-out part is shown in the figure. If a power supply line or signal line deriving unit to the motor or circuit board 11 is omitted, there is no need to provide a dedicated deriving unit.

  Further, wireless communication means can be provided on the circuit board 11 or the like, and a detection signal from the strain gauge 10 can be transmitted to the outside of the actuator by wireless communication and measured by the load measuring means such as the controller 15.

  As described above, when the bed is configured using the actuator with a built-in load sensor according to the present invention, the load sensor and the cable from the load sensor are not exposed on the floor of the patient room in order to measure the load on the bed. It is easy to ensure environmental performance such as waterproof, dustproof, impact resistance, vibration resistance and the like.

  Also, when moving the bed, it is not troublesome because it is not necessary to remove the load sensor.

  Moreover, in the above embodiment, since the support member 8 is configured to be detachable from the base body 2, it is replaced with the support member 8 having the detection cylinder 9 and the strain gauge 10 suitable for the load range to be used. By doing so, many types of actuators with different load ranges can be easily configured.

  Further, as shown in FIGS. 3 and 4, instead of the detection cylinder, a support member 8 ′ having a structure in which a support rib 16 protrudes is attached to the base body 2 instead, so that the load sensor can be mounted with the same outer shape. An actuator that is not built in can be easily configured.

  Since the present invention is as described above, it can be used for the lifting mechanism of the bed floor in hospitals, elderly facilities, general homes, etc., so as to measure the weight of the user on the bed and the body movement of the user. The means for detecting the information can be integrated with the bed, and has the advantages described above, so that the applicability is great.

  The actuator with a built-in load sensor according to the present invention can be used not only for a bed but also for medical equipment, furniture, and the like as an actuator capable of measuring a load.

  Moreover, the actuator with a built-in load sensor according to the present invention can easily constitute many types of actuators having different load ranges.

  Moreover, the actuator with a built-in load sensor according to the present invention can be used not only as an actuator but also as a load measuring device in which an operating rod can advance and retreat.

DESCRIPTION OF SYMBOLS 1 Screw shaft 2 Base 3 Female thread member 4 Drive rod body 5 Small diameter part 6 Thrust bearing 7 Actuation cylinder 8 Support member 9 Detection cylinder 10 Strain gauge 11 Circuit board 12 Signal wire 13 Output wire 14 Code cap 15 Controller 16 For support rib

Claims (3)

In the actuator in which one end side of the screw shaft is rotatably supported on the base body, an internal thread member is screwed onto the thread shaft, and an operating rod body fixed to the internal thread member is configured to be able to advance and retract in the axial direction of the thread shaft. An operating cylinder for transmitting a load from the shaft is provided on the base, and a support member is detachably attached to the base on the side opposite to the screw shaft side. A load sensor built-in actuator, characterized in that a detection cylinder that is brought into contact with the operating cylinder in a state of being mounted on the projection protrudes and a strain gauge is attached to the outer surface of the detection cylinder. The plurality of support members having different load ranges of the detection cylinder and the strain gauge are configured, and the measurement load range can be changed by a support member selected from these and mounted on the base body. The actuator with built-in load sensor described. The load sensor built-in actuator according to claim 1 or 2, wherein the load on the floor can be measured by being used as an actuator of a lifting mechanism of a bed floor.

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