JPH0729249B2 - Automatic screw fastening device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention automatically screws a threaded portion of a fastening member such as a caster into a threaded portion of a fastening member such as a chair or a blackboard to fasten both. For a screw fastening device.

When tightening screws, either the male screw part or the female screw part is held in place by an appropriate holding member, and the other is restrained and held by a tightening tool such as a spanner, but at this time, It goes without saying that both threaded parts must have a holding space for holding each threaded part.

The present invention particularly relates to a screw fastening device used when fastening a fastening member, which has a very narrow holding space for holding any one of the two screw portions, to a member to be fastened.

(Prior Art) As shown in FIG. 6, for example, a caster (universal wheel) 1
When the screw is fastened to the leg frame 2 of a chair or the like, the male screw portion 3 provided on the caster 1 for screwing is attached to the leg frame 2
In this case, the wheel support frame 4 is horizontally rotatable via the thrust bearing 5 with respect to the male screw portion 3, so that when the male screw portion 3 is held by, for example, a spanner. Since the support frame 4 is free (rotatable) with respect to the male screw portion 3, the male screw portion 3 cannot be restrained even if the supporting frame 4 is held by a spanner. For this reason, in order to hold the male screw portion 3 in a constrained manner, a spanner is applied to the angular shaft portion 6 integrated with the male screw portion 3 which is a very narrow holding space between the support frame 4 and the member 2 to be fastened, so that While holding the fastening member 2 in place, the fastening member (caster) is operated by the spanner operation.
The male screw portion 3 of 1 is screwed into the female screw portion 7 of the member to be fastened (leg frame) 2 to fasten the both.

In this way, the fastening member 1 has obstacles such as the support frame 4, and the holding space α for holding the male screw 3 in a restrained manner is very narrow, so that both screw portions are automatically fastened under these constraints. It has been difficult to screw them together by a manual work such as a spanner operation.

(Problems to be Solved by the Invention) The present invention has a narrow holding space for holding one of the threaded portions of the fastened and fastened members in a constrained manner and has an obstacle even if there is an obstacle. The object is to automatically screw both members together without any restrictions.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the invention according to claim 1 is such that a screw portion 3 formed of a male screw portion or a female screw portion of the fastening member 1.
Is a device for screwing both members 1 and 2 into each other by screwing them into a threaded portion 7 formed of a female screw portion or a male screw portion of the fastened member 2, and the fastened member 1 includes a pair of clamp arms 29, 29.
Is clamped by and is supported so as to be rotationally driven together with the clamp arms 29, 29, while the fastened member 2 is held in place with the fastened portion 7 screwed into the fastened screw portion 3 of the fastening member 1. The screw part 3 of the fastening member 1 clamped by the pair of clamp arms 29, 29 is rotationally driven together with the clamp arms 29, 29, and is required for the screwed part 7 of the fastened member 2 in the fixed position. When screwed into the tightened state, the clamp arm 29 is held by the rotational driving force of the clamp arms 29, 29 so as to be displaced from the fixed position, and the clamp arm 29 is detected by detecting the displacement of the fastened member 2. The configuration in which the detection means 39 for stopping the rotational driving of the motors 29, 29 is provided is used.

The invention according to claim 2 is the same as the invention according to claim 1,
The pair of clamp arms 29, 29 are pivotally attached to the upper end of the rotary drive shaft 10 that is rotationally driven so as to be openable and closable, and a spring that biases the pair of clamp arms 29, 29 in an opening direction that is a non-clamping direction. On the other hand, a means 31 is provided, which penetrates the hollow inside of the rotary drive shaft 10 and rotates integrally with the drive shaft 10, but is provided concentrically with a lift drive shaft 13 that drives the drive shaft 10 up and down independently. A cam means 24 is provided at the upper end of the lifting drive shaft 13 for urging the pair of clamp arms 29, 29 against the urging force of the spring means 31 in a closing direction which is a clamping direction. To do.

The invention according to claim 3 is the same as the invention according to claim 2,
The cam means 24 employs a configuration including an inclined cam surface 33a for urging the pair of clamp arms 29, 29 in the clamping direction and a flat cam surface 33b for maintaining the clamped state. .

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, a fastening member mounting base 25 is provided on the upper end portion of the rotary drive shaft 10, and the pair of clamp arms 29 sandwich the mounting base 25. , 29 are pivotally mounted so as to be openable and closable, and the clamp claws 30, 30 are provided so as to be opposed to the fastening member 1 on the mounting table 25 on both clamp arms 29, 29. is there.

(Operation) In the invention described in claim 1, the screw member 3 is held in place by rotating the fastening member 1 integrally with the clamp arms 29, 29 while being clamped by the pair of clamp arms 29, 29. Since it is adapted to be screw-fastened to the threaded portion 7 of the fastened member 2, it suffices if there is a holding space enough to clamp the fastened member 1 with the clamp arms 29, 29. The screw 2 is securely fastened to the clamp arms 29, 29 without being shaken.

Further, when the threaded portion 3 of the fastening member 1 is screwed into the threaded portion 7 of the fastened member 2 and a required screw fastening force is reached, the fastened member 2 is displaced by being biased by the screw fastening force. Is detected by the detection means 39 to stop the screw stop work, the fastening force of the fastening member 1 to the fastened member 2 can be kept constant, and insufficient fastening or excessive fastening is not caused. .

According to the invention described in claim 2, the fastening member 1, the pair of clamp arms 29, 29 for clamping the fastening member 1, and the pair of clamp arms 29, 29 are urged in the clamping direction via the cam means 24. Since it is configured to rotate together with the lifting drive shaft 13 that is coaxial with the rotating shaft, a smooth screw fastening action is exhibited without being adversely affected by an eccentric action or the like at the time of screw fastening.

According to the third aspect of the invention, the cam means 24 for urging the pair of clamp arms 29, 29 in the direction of clamping the fastening member 1 is provided with the flat cam surface 33b for maintaining a constant clamped state. Therefore, the fastening member 1 during the screw fastening work
The flat cam surface 33b receives the reaction force in the non-clamping direction that is applied to the cam means 24 and the lifting and lowering drive shaft 13 integrated with the cam means 24 so that they are axially retracted, that is, lowered. No reaction force is applied.

According to the invention described in claim 4, the fastening member mounting base 25 is provided with the pair of clamp arms 29, 29 sandwiched therebetween, and the pair of clamp arms 29, 29 is arranged so as to face the fastening member 1 mounted thereon. Since the clamp claws 30 and 30 are provided in a protruding manner, the fastening member 1 only needs to have a narrow holding space for being clamped by the clamp claws 30 and 30.

(Embodiment) FIG. 5 shows an embodiment of the present invention, in which a caster 1 (FIG. 6) is used as a fastening member, and a chair or a leg frame 2 of a blackboard is used as a fastening member to which the caster 1 is screwed. 1 shows a so-called caster screw fastening device. Hereinafter, this caster screw fastening device will be described as an embodiment.

With reference to FIG. 5, FIG. 1 and FIG. 2, 9 is a machine frame, and inside the machine frame 9, as shown in FIG. 1, a hollow rotary drive shaft having spline teeth on its inner surface. A bearing 10 is supported in an upright state by a support rail 12 which is integral with the machine frame 9 via a bearing 11. An elevating drive shaft 13 in the form of a spline shaft is provided vertically through the hollow inside of the rotary drive shaft 10, and both shafts 10 and 13 rotate integrally by spline coupling as shown in the figure. Can be further moved up and down. That is, the lower end portion of the lifting drive shaft 13 is rotatably supported by a bearing block 14 as shown in FIG. 2, while the block 14 is provided with detent pins 15 and 15 in a protruding manner. By loosely fitting 15 into the guide grooves 17 and 17 of the guide frames 16 and 16 attached to the machine frame 9, the block 14 is supported so as to be vertically movable only.

Further, a pneumatic cylinder 18 is attached with the guide frames 16, 16 sandwiched therebetween, and the piston rod 18a of the cylinder has a bearing block 1
It is screwed into 4 and is integrally connected. Therefore, as shown in FIG. 1, the motor 19 attached to the support bar 12
The rotation driving force of the is transmitted to the rotation driving shaft 10 via the pulley 20, the belt 21 and the pulley 22 to rotate the driving shaft 10.
At the same time, the lifting drive shaft 13 inside the hollow of the rotary drive shaft 10 also rotates integrally due to the spline coupling, and while the lift drive shaft 13 also rotates, it is urged by the piston rod 18a of the pneumatic cylinder 18 and passes through the bearing block 14. It is adapted to be lifted and lowered independently of the rotary drive shaft 10.

As shown in FIG. 1, a cam means 24 is integrally provided on the upper end of the lifting drive shaft 13, while the upper end of the rotary drive shaft 10 has a cam means 24 as shown in FIGS. 1 and 2. A fastening member mounting table 25 extending upward with the 24 interposed therebetween is integrally provided, and the mounting surface 25a of the mounting table 25 is exposed above the upper surface of the machine frame 9 as shown in FIG. A holding recess 26 and a holding base 27 are provided on the surface 25a so that the caster 1, which is the fastening member 1, can be stably placed on the surface 25a.

Further, a pair of clamp arms 29, 29 are pivotally attached to both sides of the fastening member mounting table 25 with the support shafts 28, 29 on both sides of the mounting table 25, and the upper ends of both clamp arms 29, 29 are pivoted. The flat plate-shaped clamp claws 30 and 30 are projected at right angles to face the casters 1 on the mounting table 25, while the clamp claws 30 and 30 are provided between the lower parts of both clamp arms 29 and 29. A spring means 31 for urging the clamp arms 29,
Each lower end of 9 abuts the cam surface 33 of the cam means 24 via the rollers 32, 32, and the cam means 24 clamps the clamp claws 30, 30 against the biasing force of the spring means 31. It is designed to bias in the closing direction. The cam surface 33 is composed of an inclined cam surface 33a and a flat cam surface 33b following the inclined cam surface 33a for the reason described later.

As shown in FIG. 3 and FIG. 5, a holding base 35 for holding the other end of the leg frame 2 which is the fastened portion is attached to the side surface of the machine frame 9, and a step portion 35a is formed on the holding base 35. Has been done.
A support block 38 is provided on the upper surface of the machine frame 9 so that the detection pin 36 can freely move in and out, facing the leg frame 2 held by the holding table 5, and is normally urged by a spring 37 to be in a protruding position. And a limit switch 39 for detecting the retreat operation when the detection pin 36 retreats against the urging force of the spring 37. Reference numeral 40 is an operation unit such as an operation switch, an indicator lamp, and an emergency switch.

Next, the method of use will be described. As shown in FIG. 1, particularly FIG. 2, the caster 1 as a fastening member is stably placed on the fastening member mounting base 25 by using the holding recess 26 and the holding base 27, Next, the female screw portion 7 at one end of the leg frame 2 is placed on the male screw portion 3 of the caster 1 so as to slightly engage with the screw portion 3, and the other end is placed on the holding base 35 so as to abut the step portion 35a. Then, by operating the operating portion 4, the elevating drive shaft 13 is urged by the pneumatic cylinder 18 to rise, and is urged by the cam means 24 at the upper end thereof to move both clamp arms 29, 29 in the closing direction.
The wheel support frame 4 (see FIG. 6) is avoided from both sides of the caster 1 by the clamp claws 30, 30 to clamp the angular shaft portion 6 (see FIG. 6) which is a narrow holding space.
What should be noted when clamping is as shown in FIG.
The trochanter 32, 32 at the lower end of both clamp arms 29, 29 is the cam surface 33.
That is, it moves from the inclined cam surface 33a and abuts and is supported by the flat cam surface 33b. When the caster 1 is clamped by both clamp arms 29, 29, the rotary drive shaft 10
Is rotated, the fastening member mounting base 25 integrated with it, the caster 1 mounted on this, and both clamp arms 29, 29 for queuing the caster 1 rotate integrally, and the male screw part 3 of the caster 1 is connected to the leg frame 2 It is screwed into the female screw portion 7 of. With this screwing work, both clamp arms 29,29
A screwing reaction force acts on the lower end trochanters 32, 32 of both clamp arms 29, 29 so that they are supported in contact with the inclined cam surface 33a. The action of pushing down works, and along with this, the clamp claw 2
However, according to the present embodiment, the rollers 32, 32 of both clamp arms 29, 29 are supported by abutting against the flat cam surface 33b during clamping as described above. The force that pushes down the lifting drive shaft 13 does not act, and the clamped state by the clamp claws 30 is reliably maintained.

The male screw part 3 is turned to the female screw part 7 by the rotation drive of the rotary drive shaft 10.
When the required fastening force is reached, the leg frame 2
When the rear end of the holding base 35 is separated from the stepped portion 35a of the holding table 35 by the fastening force, and the pressing force of the spring 37 is overcome by the displacement force of the leg frame 2 due to the fastening force, the detection pin 36 is pressed to cause the limit switch 39. Is actuated, the rotation drive of the rotary drive shaft 10 is stopped by this detection signal, the lift drive shaft 13 is lowered, and the caster 1 screwed to the leg frame 2 is released from the clamped state of both clamp arms 29, 29. Then, the screw fastening work is completed.

In this embodiment, the caster 1 serving as the fastening member has a male screw portion 3
The screw fastening device in which the leg frame 2 as the member to be fastened has the female screw portion 7 has been described, but as is clear from the above, the caster side has the female screw portion and the leg frame side has the male screw portion. In any case, it is natural that the screws can be fastened under exactly the same conditions.

(Effect) According to the invention described in claim 1, when the threaded portion of the fastening member is screwed to the threaded portion of the fastened member, the holding space for restraining the fastening member without shaking for screwing the fastening member is provided. Even if the number is small, it is possible to automatically fasten the screw without the conventional manual work, and the workability is significantly improved.

Further, when the threaded portion of the fastening member is screwed into the threaded portion of the fastened member and the required screw fastening force is reached, the fastened member is biased by the screw fastening force and displaced, and this displacement is detected by the detection means. Then, the screw stop operation is stopped, whereby the fastening force of the fastening member with respect to the fastened member can be kept constant, and insufficient fastening or excessive fastening is not caused.

According to the invention of claim 2, a clamp for the fastening member,
Since rotation driving for screw fastening is performed coaxially, smooth screw fastening work can be performed and the entire device can be compactly housed.

According to the third aspect of the invention, even if a strong screw fastening reaction force acts on the fastening member during the screw fastening work, the clamping force for clamping the fastening member does not decrease, and the stable clamping force is maintained. be able to.

According to the invention as set forth in claim 4, even if an obstacle is attached to the fastening member, which obstructs the fastening of the fastening member without shaking for screwing the fastening member, it is possible to securely restrain the fastening member. Therefore, many types of fastening members can be screwed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a clamped state of a caster screw fastening device according to an embodiment of the present invention, and FIG. 2 is a II-I of FIG.
I arrow view, FIG. 3 is a plan view, FIG. 4 is a longitudinal sectional view showing the caster unclamped state of the device, FIG. 5 is a perspective view of the device, and FIG. 6 is a caster and a leg frame. It is explanatory drawing which shows a screw fastening state. 1 ... Caster (fastening member), 2 ... Leg frame (fastened member), 3 ... Male screw part, 7 ... Female screw part, 10 ...
Rotation drive shaft, 13 ... Lift drive shaft, 24 ... Cam means, 25 ...
... Fastening member mounting table, 29 ... Clamp arm, 30 ... Clamp claw, 33a ... Inclined cam surface, 33b ... Flat cam surface, 39 ...
… Limit switch (detection means).

Claims (4)

[Claims] 1. A device for screwing a threaded portion formed by a male thread portion or a female threaded portion of a fastening member into a threaded portion formed by a female threaded portion or a male threaded portion of a fastened member to fasten both members to each other by screwing. The member is clamped by a pair of clamp arms and supported for rotation with the clamp arms, while the fastened member is held in place with the fastened portion screwed into the threaded portion of the fastening member. When the screw portion of the fastening member that is configured and clamped to the pair of clamp arms is driven to rotate together with the clamp arm and is screwed into the screwed portion of the fastened member in a fixed position in a required fastening state, the clamp arm rotates. The clamped member is held by the driving force to be displaced from the fixed position, and the clamp arm rotation is stopped by detecting the displacement of the clamped member. Because of the detection means automatic screw fastening device thus provided is. 2. The pair of clamp arms is pivotally attached to an upper end portion of a rotary drive shaft that is rotationally driven so as to be openable and closable.
A spring means for urging the pair of clamp arms in an opening direction, which is a non-clamping direction, is provided, and while rotating through the hollow inside of the rotary drive shaft to rotate integrally with the drive shaft, it is lifted and lowered independently of the drive shaft. An elevating drive shaft for driving is provided concentrically, and a cam means for urging the pair of clamp arms in a closing direction, which is a clamping direction, is provided at an upper end portion of the elevating drive shaft against the urging force of the spring means. The automatic screw fastening device according to claim 1. 3. The cam means according to claim 2, wherein the cam means comprises an inclined cam surface for urging the pair of clamp arms in the clamping direction and a flat cam surface for maintaining the clamped state. Automatic screw fastening device. 4. A fastening member mounting base is provided on an upper end portion of the rotary drive shaft, and the pair of clamp arms are pivotally mounted so as to be openable and closable with the mounting base interposed therebetween, and both clamp arms are mounted on the mounting base. The automatic screw fastening device according to any one of claims 1 to 3, wherein a clamp claw is provided so as to face the fastening member.