JPH08205573A - Motor control circuit - Google Patents

Abstract

PURPOSE: To realize accurate speed control of a motor by connecting a triac switch means, including a trigger input for applying AC power to the motor in response to an error signal and equalizing the motor speed to a desired speed between an AC power supply and the motor. CONSTITUTION: A comparator 348 responds to the analog reference signal from an analog reference circuit 342, and the average error signal between the speed indication signal from a speed indication circuit 326 and the feedback signal from a feedback circuit 330 and then generates a trigger pulse, which is a function of both signals, from an output 350. A triac switch means 320, having a trigger input 322 responsive to the trigger pulse and applying an AC power corresponding to the error signal to a motor M, in order to substantially equalize the actual motor speed to a desired speed is connected between an AC power supply 316 and a motor M. This constitution realizes precise speed control of the motor M.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor control device. Although the present invention has various applications,
For the sake of clarity, it will be described here as being used to control a motor for driving a flywheel used in a fastener driving machine. It should be understood that the description of the motor control device here is merely an example, and the present invention can be applied to various uses and applications of motor control.

[0002]

2. Description of the Related Art Conventionally, when a relatively large energy propulsion device is required to operate a fastener driving tool (for example, a nail or staple driving machine) used for manufacturing a frame,
It is usually powered by compressed air. Therefore, compressed air driven fastener driving machines that require compressors at construction sites are well known. Such a fastener driving machine can also drive nails or staples having a length of 3 inches or more into a frame having a thickness of 2 × 4 inches.

Electric type, for example, solenoid type fastener driving machines are also well known. This type of fastener driving machine is not a heavy-duty type such as frame manufacturing, but is used for light work such as driving 1-inch long headless nails.

On the other hand, efforts have been made to develop a high-power fastener driving machine that does not use a compressor. For example, a flywheel is used as a means for supplying sufficient power for driving heavy-duty fasteners. U.S. Pat.Nos. 4,042,036, 4,121,745, 4,204,622,
And British Patent No. 4,298,072.

Although a fastener driving machine driven by a flywheel has been developed over a long period of time, the flywheel type nevertheless has its own problems. For example, in the case of a driving machine using two flywheels, it is usual to supply different power to each vehicle. There is also the difficulty of having two motors which adds weight and bulk and must be synchronized. Another method is to attach one flywheel to the electric motor shaft and then drive the other flywheel with a series of belts, chains, pulleys, etc. However, this method is complicated and difficult to adjust, and there are many maintenance problems such as failures.

Another problem with such a drive is found in a device that moves one flywheel toward or away from another flywheel. For example, a movable flywheel can be moved in the work space with respect to a fixed flywheel, but one edge is closer to the maximum thickness of the driver than the other edge so that the driver can be driven between the two wheels. It is a little separated. Next, the movable flywheel is moved to the opposite side of the work rest position, the movable flywheel is separated from the fixed flywheel by a distance equal to or larger than the maximum thickness of the driver, and the peripheral edges of the movable flywheel move a distance equal to or larger than the maximum thickness of the driver. Is being done. The conventional movement system for moving the vehicle closer to or farther from the other side of the vehicle has been complicated and diverse, and has been unsatisfactory. It wasn't.

Further, the research on this kind of equipment is also directed to a means for returning the driver from the final working position to the normal retracted working rest position, which is complicated by complicated springs, pulleys and elastic strings. Various systems have been developed. However, such a system is apt to be damaged in the extension portion due to foreign matter entering the housing or stress caused by lubricating oil, which is a problem in terms of durability. Further, when a spring is used, the stroke for urging the spring is too large, and since the spring has low durability, it has to be replaced. Other systems include those that employ powered return rollers and idler rollers to move the free-floating drive element to its normal position after driving.

In addition to these problems, another problem arises when the flywheel is used as an energy source due to the nature of the driving tool. In particular, energy is transferred from the flywheel to the fastener driver, or piling means, which is rotated at high speed to provide sufficient drive when coupled to the fastener driver. For example, in the case of a typical frame-making fastener driving machine in which the length of the fastener is about 31/2 inch to 4 inch, even if the object is general wood, a driving force of about 50 horsepower is required.

When the flywheel drives the fastener, energy from the flywheel is consumed and the rotational speed of the desired flywheel is decelerated, and the fastener is driven with the same power before the desired rotational speed enters the next driving operation. Must be recovered so that it can be repeated. However, the time it takes to accelerate the flywheel to return to the desired or set speed is much longer than the period the user wants to move to the next driving operation. In other words, the physical limits of known flywheel drive systems found in such a driver limit the cycle or repetition rate that the driver can be used with.

The energy drive source system using a flywheel is usually designed to transmit energy propulsive force of a similar power several times, but when the flywheel slows down and exceeds the time increment, The above functions are practically difficult to control. Therefore, there is a need for a system in which the flywheel can be accelerated very quickly to restore the desired speed within the time that a normal cycle of use can be achieved.

In this connection it should be considered that the desired speed reached by the flywheel must be such that it can be recovered in a repeatable and sustainable manner, but also accurately controlled. is there. Excessive driving, insufficient driving, or uneven speed results in excessive power or insufficient power that makes fastener driving too deep or too shallow.

Another consideration regarding fastener driving machines is related to the length and shape of the fastener and what the fastener is to be driven into. The heavy-duty fastener driving machine can be adjusted in response to such changes in conditions, and at the same time, the fastener driving operation can be rapidly and continuously repeated within a certain operating range. Is desirable.

Specifically, if the mechanical and design specifications of the flywheel are determined and the magnitude of the driving force to be used is determined, the angular velocity required for the flywheel can be determined. To obtain the required consistency and repeatability of drive operation without over- or under-driving the fasteners, regulate the speed change of the electric motor connected to the flywheel to within ± 1%. There must be. A typical range of the motor angular velocity is, for example, if a flywheel having a weight of 0.87 pounds and a moment of inertia of 4.016 × 10 −4 ft.-lbs.sec 2 is used, 7,000 rpm to 15,000 rpm.
It is 0 rotation. In addition, the flywheel speed is reduced because the energy is consumed when the driver drives the fastener.
The motor must then accelerate to return to the selected desired speed within 500 milliseconds. It is also necessary that the motor and the motor control circuit are not affected even in a noisy environment. In addition, the driving machine is subject to considerable voltage fluctuations and frequent frequent instantaneous power increases [power
Often used in environments exposed to [hook ups]. The motor and motor controller are required to have a minimum weight and cost of manufacture that can be commercially sold as a portable driver.

It is a well known fact that there are currently many motor speed controllers that can be used with various types of motors. For example, Motorola TDA 1085C is an integrated circuit that can control the motor for both AC and DC, and is a voltage comparison velocity feedback loop.
p] with a triac phase angle controller.
There are many prior art motor speed controllers using phase locked loops (PLLs) that are mainly used for brushless DC motor control. Much is known about the theory and practice of using a phase locked loop instead of phase angle control to control an AC / DC motor. Furthermore, there is already a portable, one-handed driving machine that can select the speed. However, these conventional types are essentially open-loop and do not require precise closed-loop control. Such an open loop speed control system can be obtained by switching the power supply to the motor during half or full wave, by connecting or disconnecting the selected motor coil to the circuit, or by mechanical gear operation. it can. In addition, a portable handheld device using a battery as a power source usually supplies a pulse width modulation current to a permanent magnet field type motor.

However, none of these conventional circuits is capable of controlling the speed of an AC / DC motor having the speed range of the present invention and capable of responding in an accurate time.

Thus, fasteners of various lengths,
A reliable, lightweight, and relatively simple structure of an electromechanical fastener driving machine capable of repeatedly driving fasteners for heavy-duty frame manufacturing has never existed in this technical field until now. .

For an electric drive, especially one with a flywheel, or other handheld drive, the weight and price of the drive needs to be considered. A motor capable of complicated speed control is very heavy and expensive. Therefore, it is desired to provide a fastener driving machine which is relatively lightweight and can be used for various devices including a motor having a speed controllable motor at various prices.

As another aspect of the present invention, it is important for a handheld and manually operated type device not only to be a relatively lightweight energy source, but also to be well-balanced. Although some of the conventional fastener driving machines described above are powered by a motor-driven flywheel, both the flywheel and the motor are arranged at the tip of the driving machine. In such a driving machine, since the center of gravity is in the front, it is difficult to balance the equipment. On the other hand, in order to mount the motor far away from the flywheel, a connecting portion or a drive connecting portion is required, which has the drawback of increasing the weight of the device and reducing the efficiency of the power source. This would require a larger motor, which would result in additional weight. Thus, there is a demand for a handheld fastener driving machine in which the driving portions are arranged in a well-balanced manner.

Although the fastener driving machine needs to consider the above points, it is necessary to treat the work force such as the kinetic force or the energy applied to the work member in handling the fastener driving machine and the like. Many devices provide work members with short distances, ie, limited movement.
At present, in addition to the flywheel system and the compressed air system described above, an electric system, a hydraulic system, a motor or solenoid system, an internal combustion engine system, a spring-loaded system, etc. are known. Examples of equipment other than fastener driving machines that utilize various energy sources for moving work members include paper line punches, other punches, scissors, cutters, pruning shears, wrenches,
There are sewing machines, rivet setting machines, etc. It would be desirable to provide an improved drive source or power unit for such equipment.

[0020]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inexpensive, highly reliable and lightweight control circuit (control device) capable of accurately controlling the speed of a motor.

Another object of the present invention is that a wide variety of motor speeds can be selected, and even if there is deceleration due to the load on the motor, the motor rotation can be quickly restored to the selected desired speed. It is to provide a motor control circuit that can perform. It is also an object of the invention to provide an improved device for transferring energy from a flywheel to a work member of a fastener driving machine or other equipment.

Another object of the present invention is to provide a power unit for driving a flywheel at a selected desired speed and a control circuit for the same, and in particular a control circuit for rapidly recovering the selected desired speed even after deceleration of the flywheel. Especially.

Another object of the present invention is to provide an improved flywheel driven fastener driver that can produce a desired energy pulse at a desired cycle period.

[0024] Another object is to provide an improved portable handheld electric device.

[0025]

SUMMARY OF THE INVENTION In order to achieve such an object, one of the present inventions is provided.
In the embodiment, the work member of the fastener driving machine 10 is provided with a power source or a drive source. That is, the flywheel 30 is mounted in the housing 11 of the device, and the handle 12 extends rearward from the housing 11 provided with the motor M for driving the flywheel 30. The drive shaft 22 connected to the motor M is a spiral bevel tooth 2 of the flywheel 30.
It has a pinion 25 with a bevel gear meshing with 6. The weight of the motor M arranged at the rear end of the handle 12 balances the weight of the housing 11 and each member in the housing 11 so that the entire driving machine 10 can be felt in a balanced manner.

The drum 57 is arranged in the housing 11 and has a first peripheral surface 82. The first drive cable 45 is attached to the drum 57 so as to wind around the surface of the drum 57 as the drum 57 rotates. A conical clutch 55 is used to selectively and intermittently connect the flywheel 30 to the drum 57 so as to transfer energy pulses to the drum 57 to rotate the drum 57 and wrap the drive cable 45 thereon. The other end of the drive cable 45 is connected to the driver 40 of the fastener. Drum 5
When 7 rotates, the drive cable 45 winds around the drum 57 and pulls the driver 40 to engage the fastener and drive the fastener. The energy thus stored in the flywheel 30 is transmitted to the fastener via the drum 57, the drive cable 45 and the driver 40.

The cylindrical peripheral surface 86 which is the second peripheral surface has a diameter smaller than that of the winding peripheral surface 82 which is the first peripheral surface, and the drum 5
7 is operably connected. The return cable 52 of the second cable is attached to the cylindrical peripheral surface 86, and when the drum 57 is rotated by the flywheel 30, the return cable 52 is wound around the cylindrical peripheral surface 86. The other end of the return cable 52 is attached to the coil spring 50, and the coil spring 50 is compressed when the return cable 52 is wound. When the conical clutch 55 disengages the drum 57 from the flywheel 30, this coil spring 50 stretches to stretch the return cable 52, rotating the drum 57 in the reverse direction and pushing the drive cable 45 and the driver 40 back to the initial work rest position. Since the winding surface of the return cable 52 is smaller than the winding surface of the drive cable 45, when the drum 57 is activated by the flywheel 30 and the conical clutch 55, the return cable 5
2 does not travel as long as a drive cable. The moving range of the spring is maintained within a range that does not apply excessive stress or fatigue to the coil spring 50 even if the driving tool 10 is excessively cycled.

The coupling member actuated by the trigger 35 and the axially retractable actuator serve to actuate the conical clutch 55, momentarily connecting the flywheel 30 to the drum 57. Since the structure and operation of the actuator are similar to those described in the prior application, reference is made to this point and the description is incorporated herein.

A relatively simple and inexpensive AC / DC motor is used. A control circuit that matches the length and shape of the fastener and the parameters of the object moves the motor M at the selected desired speed. In addition to accelerating the motor M, the control circuit also serves to return the flywheel 30 to the desired speed within a desired cycle interval with only a very short delay of about 500 milliseconds.

By switching the phase angle of the AC with a highly reliable, low-priced and lightweight triac power switch that responds to the motor control circuit that controls the speed with the phase-locked loop, the speed of the inexpensive, highly-reliable and lightweight AC / DC motor. To control. The triac power switch is connected between the AC power supply and the motor and has a trigger input that controls the supply of AC to the motor. An analog reference circuit responds to the AC signal and activates the ramp signal at each zero crossing of the AC signal. The ramp signal has a time interval approximately equal to the time interval between each zero crossing of the AC signal.

The speed instruction circuit emits a speed instruction signal having a certain reference frequency. This reference frequency represents the desired motor speed selected from several options. A feedback circuit responds to motor rotation and produces a feedback signal having a feedback frequency corresponding to the actual speed of the motor. A phase detector emits an error signal representative of the phase difference between this feedback signal leveled by the low pass filter and the speed indicating signal. The comparator supplies a start pulse to the triac power switch in response to the detected phase difference each time the ramp signal is generated. The rising edge of the trigger pulse occurs during the duration of the ramp signal with a timing determined by the phase difference between the reference frequency and the feedback frequency. When the trigger pulse turns on the triac in response to the phase difference, an AC signal is applied to the motor to synchronize the phase of the speed indication signal and the feedback signal, thus maintaining the actual motor speed approximately equal to the desired motor speed. To be done.

The curved portion of the magazine 15 extends from one side of the handle 12 along the outside thereof to improve the weight balance of the entire fastener driving machine 10 and to grasp the handle 12 with either the right hand or the left hand of the user. Has been made possible. When the present invention is used as an embodiment of a fastener driving machine, it is not only inclined but also curved so as to extend rearward in the direction of the motor at the bottom of the handle and partially surround the handle from the front position below the driver. Includes fastener magazine balancing fasteners.

Of course, the power source or drive unit as described above can be used to transmit energy pulses to the work members of various devices. These units include motors, drive shafts, flywheels,
The motor may be mounted to directly drive the flywheel, including a drum, drive and return cables, a clutch trigger connection, a clutch actuator where balance and portability are not a concern. When using the present invention as a handheld device, the motor and the flywheel are accelerated to a predetermined speed in the shortest time, together with the housing, the handle extending from the housing, the motor disposed at the front end of the handle, and the motor connected to the flywheel in the housing. A shaft that extends through the handle.

It is an object of the present invention to provide a circuit which is capable of very precise speed control of a motor and deceleration from a desired speed very quickly. It is a feature of the present invention that the frequencies of the speed instruction signal and the feedback signal are not so sensitive to noise. Further, the motor of the present invention is also characterized by low cost, light weight and high performance.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A detailed description will be given below with reference to the drawings showing an embodiment of the present invention. As a preferred embodiment of the present invention, the drawing shows a fastener driving machine 10 for driving a nail N (FIG. 8) into a wall W (FIG. 8). It should be understood that the preferred embodiment includes a motor control circuit that can be used in the motors of a variety of machines that include work pieces that can move from stroke to stroke, such as driver 40. The fastener driving machine 10 has a housing 11, a handle 12, and a magazine 15. The handle 12 has a front portion 13 and a rear portion 1.
There are four. The magazine 15 is attached via a bracket 19 from the rear portion 14 of the handle 12 to the front end 17 of the housing 11. The bracket 16 serves as a leg for supporting the driving tool in a standing state when the driving tool is placed on a horizontal surface.

The magazine 15 is depicted in more detail in FIG. The magazine 15 is curved and inclined from the front side toward the back. The front end of the magazine 15 is the nose 1 of the driving machine 10.
8 is connected by a bracket 19. The magazine 15 is made to be able to send fasteners one after another to a drive unit near the nose 18 via this connecting portion, and the fastener can be driven from this drive unit when the driving tool is operated. Since the fastener is driven into the target object, the fastener is sequentially delivered from the magazine 15 to the drive unit at one end of the drive element.

The curved portion of the magazine 15 extends from one side of the handle 12 along the outside thereof so that the handle 12 can be held by either the right hand or the left hand of the user.

The motor M is located in the rear part 14 of the handle 12 and is connected to the power supply by an electric cord 20. A rotational speed display, knobs, and other motor speed selectors are provided at 21 on the housing 11 to allow the user to select the desired speed depending on the length and shape of the fastener being driven and the parameters of the object. .

The magazine 15 is spring-biased so that the fasteners are continuously fired one after another.

Although not shown in FIG. 1, as will be described later, the driving tool 10 is connected to a motor M arranged at the rear portion 14 of the handle 12 so that when the motor M is operated, the flywheel 30 is rotated. .

FIG. 3 shows a part of the internal structure of the driving tool 10. A pinion 25 is provided at the tip of the drive shaft 22 supported by bearings, and spiral bevel teeth 26 are engraved on the pinion 25. The pinion 25 is provided so that its spiral bevel teeth 26 fit with the corresponding spiral bevel teeth 27 of the flywheel 30 rotatably provided on the center line 31. The driving tool 10 is provided with a mechanical trigger 35 that can be pulled in the direction indicated by arrow A in FIG.
When the motor M on the rear portion 14 of the handle 12 is operated, the drive shaft 22 and the pinion 25 rotate, and the flywheel 30 rotates clockwise.

In FIG. 2, FIG. 7 and FIG.
0 is provided with a driver element 40 that reciprocates in a cylinder 41 provided at the front end 17 of the housing 11. The rod-shaped driver element 40 is formed in a suitable shape such as a round rod or a substantially C-shape or a D-shape whose cross-sectional shape resembles the head of a fastener. Alternatively, the driver 40 may be flat, or any other suitable shape, such as rectangular in cross section. The driving tool 10 also includes a stopper 43 for the driver 40 and a coupling 42. The driver element 40 has its tip extended before the coupling 42.

A drive cable 45 is attached at its upper end 46 to the coupling 42. The drive cable 45 is preferably a flat cord made of a plurality of cords in which synthetic resin is bundled. The other end of the drive cable 45, the lower end 47
Is attached to the device that drives the driver 40.

The housing 11 has a coil spring 50.
It also has a sleeve 49 that contains. The cap 51 is connected to the upper end of the coil spring 50, and the return cable 52 is connected to the cap 51 at its upper end. The lower end 53 of the return cable 52 is also connected to the drive device so as to rotate the drive device.

In FIG. 9, a series of parts of the driving device are drawn on the center line 31. From the left side, the flywheel 30, the conical clutch 55, the drum stopper 56, the drum 57, the ball inner dish 58, the bearing cage 59, the ball outer dish 6
0, a pressing plate 61, a washer 62, a disc spring 63, and a ratchet ring 64. These parts are assembled on the center line 31 as can be seen in FIGS. FIG. 10 shows the details of the inner bowl 58 and the outer bowl 60.

In FIGS. 5, 6, 9, and 10, the flywheel 30 is driven via the helical bevel teeth 27. The handwheel 30 has a truncated cone surface 66 that receives the conical clutch 55.
(FIGS. 5 and 6), and is rotatably attached to the shaft 67 via a bearing 68 on the center line 31. The conical clutch 55 also has a truncated cone surface 70 facing the friction member 71.
Is provided. When the conical clutch 55 is pressed in the flywheel 30, the friction member 71 contacts the truncated cone surface 66, and the flywheel 30 rotates the conical clutch 55.

In FIGS. 5 and 6, a cylindrical projection 73 is attached to the bowl 58, and a spline 74 is engraved on the cylindrical projection 73 (FIGS. 9 and 10). The cylindrical projection 73 connected to the bowl inner plate 58 is fitted to the shaft 67 so as to rotate on the shaft 67 via the sleeve 75. The conical clutch 55 is provided with a plurality of inner surface splines 76. The conical clutch 55 is non-rotatably mounted on the cylindrical projection 73 by fitting with the splines 74 of the ball inner plate 58. The conical clutch 55 is held on the cylindrical projection 73 via a seal ring 77. A spring 79 is inserted between the sleeve 75 of the shaft 67 and the ball inner plate 58 at one end, and the holding plate 80 is provided at the other end.
And the spring 79 causes the conical clutch 55 and the bowl 58 to move from the flywheel 30 to the centerline 3
It is urged to move upwards by 1. Inner side wall splines 81 are engraved on the drum 57, and the cylindrical projections 73
Is fitted on a spline 74 extending from the ball inner dish 58 and is adapted to rotate therewith. Drum 57
Has a winding peripheral surface 82 for receiving the drive cable 45.

The bowl inner plate 58 is provided with a shoulder 85 at the edge of a cylindrical peripheral surface 86 around which the return cable 52 is wound. The diameter and circumference of the cylindrical peripheral surface 86 is the peripheral surface of the winding 8.
It is smaller than 2.

Therefore, the conical clutch 55 has the flywheel 3
When rotated by 0, this engagement causes the bowl 5
8 and the drum 57 are also driven, the drive cable 45 is wound around the winding peripheral surface 82 of the drum 57, and the return cable 52 is wound around the cylindrical peripheral surface 86 of the bowl 58.

In FIG. 5, FIG. 6, FIG. 9 and FIG.
Individual ball bearings 88 are located in pockets 89, 90, 91 of ball pan 58 and corresponding pockets 92, 93, 94 of ball pan 60. In FIG. 10, pockets 89, 90, 91 have tails 95, 96, 97, respectively, which tails are inclined upward toward narrow grooves 98, 99, 100. In FIG. 10, the pockets 92, 93, and 94 of the ball dish 60 also have the narrow grooves 104, 105, and 10.
The corresponding tails 101, 102, which incline upwardly toward 6,
It has 103. The inner bowl 58 is provided with a shield 109 on the periphery thereof, while the outer bowl 60 is provided with a rib 1
11 are projectingly provided, and the three dogs 112, 113, 114 are radially radiated outward along the peripheral side surface 115 of the rib 111.
Is protruding. Further, the bowl 1 has a plurality of blades 1
Numerals 17 are provided so as to radially project in the circumferential direction of the outer bowl 60.

When the respective pockets of the inner bowl 58 and the outer bowl 60 are aligned, the ball bearings 88 are housed in the pockets and retained in the bearing cage 59 (FIG. 5). On the other hand, when the ball inner dish 58 and the ball outer dish 60 are rotated with respect to each other, the ball moves and acts so as to separate these two members from each other. Details will be described later.

In FIG. 6, when the inner bowl 58 and the outer bowl 60 of the ball are separated, both the spring 63 and the spring 79 are pressed to move the conical clutch 55 to the flywheel 3.
It is pushed out so as to engage with 0, and the flywheel 30 rotates the ball inner dish 58 and the drum 57.

The ratchet ring 64 of FIG. 9 is arranged on the center line 31 so as to be adjacent to the bowl outer plate 60. Driving machine 1
When 0 is in the state of FIG. 5, the bowl 60 is not in the ratchet ring 64 and is therefore unaffected by it. In this position, the disc spring 63 holds the ball outer disc 60 on the center line 31 in a direction away from the ratchet ring 64. However, when the ball bearing 88 separates the ball inner plate 58 and the ball outer plate 60, the ball outer plate 60 enters the ratchet ring 64 on the center line 31, and the blade 117 engages with the inner blade 118 of the ratchet ring 64. The rotation of the ball outer dish 60 is prevented. In FIG. 9, FIG. 5 and FIG.
20 is provided on the drum 57 so as to engage with the stopper 56.

Preferably, the stopper 56 includes the bracket 1
It is preferable that the cushion 123 is provided on 24. The bracket 124 is the front end 1 of the housing 11 of the driving tool 10.
7 is slidably attached to a position away from the side surface of the cylinder 41, and the stopper 56 is supported at a fixed position as seen in FIG.

FIG. 7 shows the state of each part when the driving tool 10 is not operating. The drum 57 does not rotate, and the drive cable 45 extends from the drum 57 and extends in the cylinder 41 to the coupling 42 located above.
Reference numeral 5 is connected to the driver 40. The drive cable 45 is held on the drum 57 by extending its enlarged end into a suitable slot or cut in the drum 57 and allows it to extend upward in the barrel 41 along the driver 40. ing. At this time, the coil spring 50 is fully extended, and the return cable 52 is not wound around the cylindrical peripheral surface 86 of the bowl 58. As shown in FIG. 8, when the driving tool 10 is started to drive the fastener, the conical clutch 55 moves to engage the flywheel 30, and the flywheel 30 rotates the conical clutch 55 to rotate the drum 5 clockwise.
Engage 7. Then, the drive cable 45 is wound around the winding peripheral surface 82 of the drum 57, so that the drive cable 45 is suddenly pulled downward. Since the upper end of the drive cable 45 is connected to the driver element 40, it is used as energy for driving the fastener element by suddenly pulling the driver element 40 downward as shown in FIG. At this time, the cylindrical peripheral surface 86 of the bowl inner dish 58 rotates to wind the return cable 52. This causes the coil spring 50 to contract, but at the end of the drive cycle the coil spring 50 stretches and pulls the return cable 52. This imparts a counterclockwise rotational movement to the bowl inner bowl 58 and the drum 57, returning the drum 57 to the initial rest position and lifting the driver 40.
The driver 40 is thus lifted by the coil spring 50 while rotating the drum 57, and the winding of the drive cable 45 is released so as to push the driver 40 upward. FIG. 8 for drive cable 45 and drum 57
Preferably, three ball bearings or rollers 126 are provided, as shown in FIG. When the winding of the drum 57 is released by the coil spring 50, the driver element 40 is returned to the rest position and the preparation for the next cycle is completed.

In FIG. 2, FIG. 7 and FIG. 8, the nose 18 is pressed downward by a spring 129.
Has 28. FIG. 8 shows the state in which the driving tool 10 has been driven out, but the safety rod 128 is driven into the object and pushes the spring 129 back against the spring 129.

As shown in FIGS. 3 and 4, it has a first engaging claw 130 attached to a shaft 131. The first engaging claw 130 engages with the blade 117 of the ball dish 60, but when rotating in the opposite direction, that is, clockwise, the ball dish 60.
Remove from rotation and play. The first engaging claw 130 is the leaf spring 1.
It is pressed so as to engage with the blade 117 by 32, and when the ball outer dish 60 rotates counterclockwise, the first engaging pawl 130 itself and the blade 117 are inclined so that they can rotate. There is. Next, the second engaging claw 135
Are attached to a shaft 136 supported by a bracket 139. The second engaging claw 135 has a long hole 137 formed therein, and the second engaging claw 135 is attached to the shaft 136 through the long hole 137. The engaging claw 135 is not only rotatable about the shaft 136 but also has a long hole 137. It is configured so as to be movable in the lateral direction with respect to the minute axis 136. Second engaging claw 135
Is biased counterclockwise by a spring 138 as seen in FIG.

The driving tool 10 has a mechanical trigger and a linkage mechanism which is interlocked with the mechanical trigger. As shown in FIG. 3, a crank 145 is attached to the linkage mechanism around the pin 146 by being biased by a spring 147 in a counterclockwise direction. When the trigger 35 moves from the position shown by the dashed line in FIG. 3 to the position shown by the solid line, the tip 35 of the trigger 35 is moved.
a comes into contact with the crank 145, and the crank 14 rotates clockwise.
Rotate 5. Further, one end of the first link 148 is fixed to the cylinder 41 via a pivot 150. An elongated hole 151 is bored in the other end of the first link 148 so that the pin 1
It is attached to the crank 145 via 52. Further, the second link 149 is fixed to the first link 148 via the pivot 153. One end of the activation pawl 156 is stopped at the other end of the second link 149 via a pivot 157. The activation claw 156 is biased in a counterclockwise direction by a spring 158.

Further, the third link 161 is attached to the cylinder 41 to control the second engaging claw 135. Third link 1
Reference numeral 61 has an inclined edge 162 that abuts the pin 163. In FIG. 3, when the third link 161 is lifted, the inclined edge 162 engages with the pin 163 and moves the third link 161 to the right to separate it from the tail 166 of the second engaging claw 135. When the third link 161 moves, the spring 138 stopped by the protrusion 140 (FIG. 4) on the second engagement claw 135 moves to the second position.
Rotate the engaging pawl 135 counterclockwise to move the dog 11
Engage with any one of 2, 113 and 114.

In the preferred embodiment, the driver 10 is capable of driving objects to a length of at least 2 inches and about 4 inches. Approximately 50 to quickly drive a typical 3 1 / 2-inch fastener, such as a nail, into wood such as pine or toga.
Approximately 7,000 to 1,500, which requires horsepower
A flywheel 30 in the range of 0 revolutions / minute is sufficient to drive the fastener into the wood as described above. In this regard, the flywheel 30 of the present invention weighs about 0.87 pounds with a moment of inertia from the centerline 31 of about 4.016.times.10@-4 ft.lbs.sec.2. Of course, other than this, various weights, weight distributions and speeds are possible.

The speed of the flywheel 30 is 7,000 to 15,000 revolutions / hour for driving a fastener having a length of 3 1/2 inches.
It can also be reduced from the range of minutes to the range of about 4000-10000 rpm. The initially set desired speed of about 7,000 to about 15,000 rpm is recovered within about 500 milliseconds even if the flywheel is decelerated by the driving operation.

[0062]

The operation of the driving tool 10 will be described with reference to FIGS. As a specific movement, the driving machine 10 is assumed to operate up to "bottom fire". That is, the trigger is pulled to the end, but the driving tool 10 is not fired until the safety rod 128 hits the object at the final stage of one cycle.

In FIG. 11, the trigger 35 is not activated and the safety rod 128 is not applied to the object. Thus, the safety rod 128 is fully extended and the linkage mechanism is at rest. The first engagement claw 130 holds the ball outer dish 60 in a fixed position and stops the clockwise movement. The activation pawl 156 is not engaged with the blade 117 of the bowl 60.

In FIG. 12, the trigger 35 has moved to the central portion, that is, the intermediate point of the movement, and is in contact with the crank 145. The crank 145 moves slightly clockwise and lowers the pin 152 downwards to pivot the first link 148 into the pivot 15
Move down through 0 clockwise. This movement moves the pivot 153 and also moves the second link 149 mounted thereon downward. The safety rod 128 is not yet in contact with the object, and the third link 161 is also in the rest position.

In FIG. 13, the trigger 35 is pulled to the end, but the safety rod 128 is not yet in contact with the object. In this state, the activation pawl 156 is moved so as to engage with one of the blades 117 of the bowl 60. This movement is pin 152
Is moved further down and pin 153 is also moved so actuating pawl 156 is moved to engage one of blades 117.
The third link 161 is at rest.

In FIG. 14, with the trigger 35 kept pulled to the end, the safety rod 128 contacts an object such as the wood W, and the protrusion 169 abutting on the safety rod 128 is moved upward to move the second link. It contacts the tip 170 of 149.
This movement is performed by hitting the driving tool against the object W. The second link 149 has not yet moved at this stage.

In FIG. 15, when the driving tool 10 is further pressed against the object W and the safety rod 128 is raised into the housing 11, the protrusion 169 rises and abuts against the tip 170 of the second link 149 to cause the second Pivot link 149 15
Rotate around 3. This rotation pushes down the pivot 157 and pulls the activation pawl 156 downward, so that the ball outer dish 60 is rotated about 37 degrees counterclockwise in FIG. At this time, at the same time, the third link 161 connected to the safety rod 128 rises and is rotated against the bias of the spring 173. At the same time, this ascending movement pushes up the tail portion 166 of the second engaging claw 135 to rotate the second engaging claw 135 counterclockwise, and the dogs 112, 113 of the ball outer plate 60,
Alternatively, the engagement with 114 is released. Although the dog 113 shown by a broken line in FIG. 3 is engaged with the engagement claw 135, the second engagement claw 135 moves so as to come out of the dog, and allows the ball outer dish 60 to rotate. Third link 16
The movement of the safety rod 128 at 1 is linkage configured such that the second engagement pawl 135 moves to release the ball pan 60 when the activation pawl 156 is moved to pull the ball pan 60 counterclockwise. There is. Rotation of the second engagement pawl 135 releases the ball bowl 60 from the dog and moves linearly over the dog and stops there, but these movements are enabled by the slot 137 (FIG. 3). In this position, there is no further blocking of the rotation of the bowl 60.

As shown in FIGS. 11 to 15, when the trigger is pulled to the end and the safety rod 128 is completely brought into contact with the object, the ball pan 60 is rotated about 37 degrees counterclockwise.

In FIGS. 5 and 6, the above-mentioned movement changes the inner bowl 58, outer bowl 60, conical clutch 55 and flywheel 30 from the state of FIG. 5 to the state of FIG. That is, FIG. 6 illustrates the movement when the actual driving or rotation starts. In particular, rotation of the bowl outer plate 60 will move the ball axially toward the flywheel 30, since, for example, the tail 101 will be moved counterclockwise.
Therefore, the ball is trapped in the bowl inner dish 58 and the tail 101 in the bowl outer dish 60 and the pocket 8 of the bowl inner dish 58.
The space between the ball 9 and the tail portion 95 contracts, and the ball outer tray 60 is axially separated from the flywheel 30, while the ball inner tray 58 is urged inwardly toward the flywheel 30 against the spring 79. When the ball outer tray 60 further rotates and the balls separate the two ball inner trays 58 and the ball outer tray 60, the disc spring 63 is compressed and the conical clutch 55 is pushed so as to contact the flywheel 30. 11 to 15
As shown in, the flywheel 30 rotates and catches the conical clutch 55, and transmits clockwise rotational energy to the conical clutch 55. This is bowl 58 and drum 5
Since both 7 are rapidly rotated clockwise, the drive cable 45 is wound around the winding peripheral surface 82 of the drum 57. When the drive cable 45 is wound up, the driver element 40 is pulled downward, so that sufficient energy for driving the fastener into the object W is generated. The return cable 52 is wound around the winding peripheral surface 82 of the drum 57.

As shown in FIG. 8, immediately before the drum 57 reaches the position where it is completely driven, the inner bowl 58 of the ball moves to the center line 31.
Since the top rotates about 203 degrees for a sufficient distance, pocket 8
9, 90 and 91 come to face the corresponding pockets of the bowl 60. Because there is a ball in the pocket,
When the spring 79 is driven away from the flywheel 30, the bowl 58 is moved along the center line 31. When the ball falls into the pocket, the disc spring 63 expands. By the movement of the spring 79, the conical clutch 5
5 is separated from the flywheel 30 and disengaged from the flywheel 30, and the energy of the flywheel 30 is not transmitted to the conical clutch 55 and the drum 57. Therefore, the conical clutch 55
Only while is engaged with the flywheel 30, energy is transferred from the flywheel 30 to the conical clutch 55 and the drum 57, moving the driver 40 and driving the fastener. Drum 5
As soon as 7 is disengaged from the flywheel 30, the projection 120 protruding from the drum 57 is locked to the elastic member 123 of the stopper 56 to stop the clockwise rotating drum 57.

At this time, at the same time, the drum 57 moves the bowl inner plate 5
8 and the cylindrical peripheral surface 86. Since the enlarged end portion of the return cable 52 is locked in the slot and wound around the cylindrical peripheral surface 86, the return cable 52 is
The drive cable 45 is wound around the cylindrical peripheral surface 86 at the same time as the drive cable 45 is wound around the drum 57. The return cable 52 pulls the cap 51 longitudinally against the end of the coil spring 50, which compresses the coil spring 50. Of course, the coil spring 50 and the return cable 52 may be connected so that the coil spring 50 expands or contracts as the drum 57 rotates, or a suitable spring having another shape can be attached.

As shown in FIG. 8, when the flywheel 30 and the conical clutch 55 are disengaged, the coil spring 50 now urges the drum 57 counterclockwise to return it to the position shown in FIG. This counterclockwise movement extends so as to release the winding of the drive cable 45, and pushes the driver element 40 upward in the non-driving state. Such a series of operations can occur even when, for example, the trigger 35 remains pulled and the safety rod 128 is retracted into the driving tool 10, as shown in FIG. Note that inner bowl 58 and outer bowl 60 have moved about 240 degrees relative to each other. It is an advantage that the movement of the pockets and tails of each of the inner bowl 58 and the outer bowl 60, and the movement of each ball, are generally identical and balanced.

16 to 18 show a method of starting the driving tool by completely abutting the safety rod 128 and then pulling the trigger 35. For example, in FIG. 16, the safety rod 128 is abutted against the object W. In this way, the protrusion 169 is lifted upward, abuts on the tip 170 of the second link 149, and lifts this upward. However, since the trigger 35 is not engaged, the crank 145 has not yet rotated and the first link 148 (not visible hidden in FIG. 16) has not yet been lowered. This is the second link 149
Will remain in the upper position, and the activation pawl 156 will not engage any of the blades 117 of the bowl 60. However, since the third link 161 is lifted and rotated, the tail portion 166 of the second engaging claw 135 is lifted, and the second engaging claw 135
Rotates counterclockwise. As described above, the second engaging claw 1
The elongated hole 137 of 35 is elongated and opened. As shown in FIG. 16, since the spring 138 (FIG. 4) urges the second engaging claw 135, the spring 138 moves the second engaging claw 135 slightly to the left, and the second engaging claw 135 is moved. The front end of 135 moves over the relevant dog on the bowl 60. Therefore, the second engagement claw 135 comes to the upper side of all the dogs on the ball dish 60 when the trigger 35 is pulled later.

In FIG. 17, the safety rod 128 remains in contact with the object W. The trigger 35 moves to half, that is, the central portion, and slightly rotates the crank 145,
The first link 148 is rotated about the pivot 150, which pushes the second link 149 down slightly to engage the activation pawl 156 with the blade 117 of the bowl 60. FIG.
At 8, the continued upward movement of the trigger 35 causes the crank 145 to rotate and the first link 148 to pivot 15.
Rotate around 0, pivot 153 and second link 149
Is pushed down, the pushing pawl 156 is pushed down. This movement causes ball bowl 60 to rotate counterclockwise (arrow 175).

Therefore, the driving tool 10 first pushes the trigger 35 and then pushes the safety rod 128 to the object, or pushes the safety rod 128 to the object and then the trigger 3
It can be activated by pressing 5. If the trigger 35 is continuously lowered, the driving tool 10 repeatedly presses the safety rod 128 against the object to operate the driving tool 10.

Although the preferred embodiment of the present invention has been described with respect to a fastener driver, the device of the present invention transfers energy to a work member for a variety of purposes, whether handheld or not. It can be used as a power unit for driving various types of equipment.

The present invention has the advantage that the energy for winding the drum 57 can be rapidly transmitted. The conical clutch 55 rapidly engages the flywheel 30 to drive the drum 57, and likewise rapidly disengages the flywheel 30 to remove energy transfer to the drum 57 and rotate the drum 57 about 203 degrees. These are achieved by the drive cable 45 that drives the driver 40. If such a device is used, it is a relatively lightweight and handheld device.
It is possible to provide a product such as x4s that exerts sufficient force to drive a nail of about 3 to 4 inches in length into wood.

Another advantage is that the bottom portion 1 of the handle 12 is
The motor arrangement of 4 makes it easy to balance the equipment, which makes it possible to provide equipment that is easy to hold and easy to use and has little fatigue.

Since the bevel gear having a spiral blade is used, there is an advantage that energy is smoothly transmitted from the motor to the flywheel, and there is no disadvantageous loss required for an unnecessarily large motor.

[0080]

[Motor Control Circuit] FIG. 19 is a block diagram showing a motor control circuit 310 for controlling the speed of the AC / DC motor M. The lead wire 314 from the motor is AC 120V 6
It is connected to a 0 Hz power supply 316. Another lead wire 318 from the motor is connected to a power supply 320, which is connected to the power supply 316 by a lead wire 324.
It is connected to the. The power supply 320 is a triac [triac]
A trigger input 322 is included, which includes 321 and activates it. Power switch 320 uses the trigger pulse at trigger input 322 to control the phase angle conducted by triac 321. By this, the lead wire 324 to the motor M
The supply of AC signals to the is controlled.

The motor control circuit 310 of FIG. 19 has a speed instruction circuit 326. This circuit 326 produces a speed indication signal at a reference frequency at output 328 to achieve the desired speed of motor M. Feedback circuit 330 produces a feedback signal at output 332 in response to the rotation of the motor. This signal has a frequency proportional to the actual speed of the motor M. Phase detector 334 is responsive to the speed indicating signal and the feedback signal and produces an error signal at output 336 as a function of the phase difference between the two signals. Low pass filter 3
38 is connected to phase detector 334 and produces an averaging error signal at output 340 as a function of the error signal at output 336. An analog reference circuit 342 is connected to the power supply 344 and produces an analog reference signal at its output 346. Comparator 348 responds to these average error signals and the analog reference signal. A trigger pulse is then generated at output 350 as a function of the analog reference signal and the average error signal. Triac 32 is the trigger pulse
This TRIAC 321 is instructed to switch the phase angle of 1
Controls the supply of the AC signal on line 324 to the AC / DC motor M such that the phase of the feedback signal on output 332 is synchronized with the phase of the speed instruction signal on line 328.

The speed instruction circuit 326 has a selector switch 352 connected to the voltage source 354. The selector switch 352 has several selectable input modes corresponding to a plurality of selectable desired motor speeds. This desired motor speed is a function of the desired work force to be generated by the power equipment. In the case of the powered fastener driving machine according to the present invention, the selector switch 352 displays the condition such as the fastener size and the fastener driving depth into the object. Each setpoint, depending on the magnitude of the work force, is generally determined by reference to a table showing fastener lengths, drive depths, and proper setpoints for the target. The selector switch 352 has a plurality of outputs 3 corresponding to the number of selectable modes of the selector switch 352.
I have 56. A reference frequency oscillator 358 is connected to the selector switch 352 and provides an output line 328 with a speed indicating signal having a desired motor speed reference frequency. For example, the reference frequency oscillator 3 corresponds to 10 types of input modes selectable by the selector switch 352.
58 supplies ten kinds of reference frequencies, for example, 4 kHz to 8 kHz. The display 355 also operates in response to the selector switch 352 to visually provide the operator with the selected input value.

The feedback circuit 330 is a feedback converter 3 which responds to the rotation of the motor M as shown by the broken line 362.
Has 60. The feedback converter 360 is any device capable of responding to the rotation of the motor, changing its output signal to represent the actual speed of the motor M. Zero cross detector 3
Reference numeral 64 is connected to the feedback converter 360 and supplies a feedback signal having a frequency proportional to the angular velocity of the motor M to the line 332.

Power source 34 connected to AC power source 316
4 supplies some DC voltage at output 366. These outputs 366 are used to power other devices in the motor control circuit 310. Analog reference circuit 34
2 includes a zero cross detector 368, which outputs 37 in response to zero crossing of the AC signal from AC power supply 316.
A zero-crossing sync signal is generated at zero. The analog reference circuit 342 also includes a lamp oscillator 372, which produces an analog reference signal at the output 346. The analog reference signal is a series of ramp signals, each of which is activated in response to zero crossing of the AC signal. Subsequent zero-crossing of the AC signal ends the ramp signal at that point,
Start the next ramp signal. Therefore, if the AC signal is 60 Hz, the ramp signal will be generated at a frequency of 120 Hz. The ramp signal has a minimum value [a minimum magnitu
de value] is a time-varying analog reference signal whose value increases linearly with time until the ramp signal ends. The comparator 348 responds to this ramp signal and the averaging error signal from the low pass filter 338,
A trigger pulse signal is generated at output 350 when the value of the averaging error signal exceeds the value of the ramp signal.

The power switch 320 is connected to the driver 374. This driver 374 shapes the trigger pulse on line 350 into the input 322 of the triac 321. Therefore, the trigger pulse on line 350 causes the triac 321 to conduct or turn on at the phase angle of the AC signal determined by the point of interception of the averaging error on line 340 and the ramp signal on line 346. . AC power is applied to the motor according to the firing phase angle of the triac, and the triac 321 is turned off when the AC signal from the AC power supply 316 passes the next zero crossing point. The net effect of synchronizing the phase of the feedback signal on line 332 with the phase of the speed indication signal on line 328 is to equalize the actual speed of motor M to the desired speed selected by switch 352. By utilizing the phase as a control variable, the motor is very precisely controlled in its speed to the desired value.

FIG. 20 is a detailed circuit diagram showing the individual components used in the motor control circuit 310 for speed control of the motor M, for example, an AC / DC DC brush type motor of about 0.625 hp. A line 380 from the AC power supply 316 is connected to a manually operated on / off switch 382. This on / off switch 382 is provided in a circuit that supplies current to one set of motor field winding 384, motor armature 386 via brushes 388, 390, another set of motor field winding 392, and output 394 of triac 321. It has been placed. The common line 396 of the AC power supply 316 is connected to the power input terminal 398 of the triac 321.
An example of a device that can be used as the triac 321 is MAC15-6 manufactured by Motorola, USA.

The power supply 344 (lower right of the figure) is connected to the lines 380 and 396 of the power supply 316, and outputs 400 to 5 are connected.
The DC voltage of V and the DC voltage of 12 V are output from the output 402. These supply voltages are derived from the half-wave rectified AC signal generated by diode D1 and power-type resistor R1. The DC voltage at the outputs 400, 402 must be sufficiently stable and noise free to power the integrated circuits and other devices in the motor control circuit 310.

The lines 380, 396 of the power supply 316 are also connected to the zero cross detector 368. This detector 3
68 is a transistor Q4, Q5 (for example Motorola 2
N3904) and resistors R10, R11, R12, and R13. When the AC signal passes through the zero-crossing point from negative to positive, the current through resistors R12 and R13 goes to zero and transistor Q4 switches off. Therefore, the voltage level of the collector 404 of the transistor Q4 is approximately DC + 5V (“VDC”) power supply voltage Vcc.
Switch to. When the AC signal rises in the positive direction, the current from resistors R12 and R13 immediately biases transistor Q4 on, thereby returning the collector 404 of transistor Q4 to ground. That is, the first zero-cross pulse having a narrow pulse width is generated by the collector 40 of the transistor Q4 at each negative-to-positive zero crossing.
4 is generated.

During the subsequent positive-to-negative zero crossing of the AC signal, the AC signal passes through the zero cross point. Therefore, the transistor Q4 is turned off again, and the collector 404 rises to approximately + 5V DC. When the AC signal goes negative, transistor Q5 switches on and the current flow through resistors R10, R11, R12, R13 rapidly biases transistor Q4 off, causing collector 404 of transistor Q4 to return to approximately ground. That is, a narrow second zero-cross pulse is generated at the collector 404 of transistor Q4 at each positive-to-negative zero-crossing of the AC signal.

The zero cross detector 372 in the analog reference circuit 342 drives the ramp generator 372. The lamp generator 372 is composed of a transistor Q3, a capacitor C3 and a resistor R9. Transistor Q3 switches on at each positive change, ie, the rising edge of each zero-cross pulse corresponding to each zero-cross. As a result, a discharge path is formed in the capacitor C3. When transistor Q3 is switched off on each trailing edge, the negative going edge of each zero-cross pulse, capacitor C3 is gradually charged by the current flowing through resistor R9. This slow charging of capacitor C3 results in a voltage level that increases almost linearly with time, thereby producing a roughly ramp signal (sawtooth signal). This ramp signal is
It ends at the leading edge of the next zero-cross pulse and has a direct current of about 0 V (VD
Return to the initial level of C). Therefore, for an AC signal of 60 Hz, the zero-cross pulse is generated at a frequency of 120 Hz. Each successive zero-cross pulse initializes each successive ramp signal at a frequency of 120 Hz.
The ramp signal is an analog reference signal that is synchronized with the zero crossing of the AC signal, and its value is different at each point in the half-wave process within each half-wave time of the AC signal. It also has a voltage level that is unique.

In the speed instruction circuit 326, the acceleration button 4
06 and a deceleration button 408, a speed selector switch 352 is installed to provide input to the digital potentiometer 410. Digital potentiometer 4
10 (For example, Dallas Semiconductor Company DS1669)
Has an output 412 connected to an operational amplifier U4. An example of the operational amplifier U4 is TLC272 manufactured by Texas Instruments Incorporated. Digital potentiometer 4
The output 412 of 10 has 64 stages in response to an acceleration or deceleration input instruction provided by pressing a button 406, 408. The operational amplifier U4 is a voltage controlled oscillator U5 (eg Motorola MC54 / 74 HC4046A).
Is connected to a reference frequency transmitter 358. Operational amplifier U4 acts as a bias generator for voltage controlled oscillator U5. The output 414 of operational amplifier U4 is connected to its input 416 via resistor R17. In response to the change in the voltage level of the output 412, the operational amplifier U4
Input 416 of operational amplifier U4 draws current from voltage controlled oscillator U5, thereby providing a power drop across resistor R16 as a function of the output signal of output 412 of digital potentiometer 410. Voltage controlled oscillator U5 produces a reference frequency on output 328. The frequency corresponds to the speed instruction determined by operating the buttons 406 and 408. The desired power generated by the equipment is given as a function of the kinetic energy stored in the rotating flywheel. This kinetic energy is equal to 1/2 (I) (ω2). Here, I is the moment of inertia of the flywheel, and ω is the angular velocity of the flywheel. Therefore, the reference frequency is a value for realizing a desired motor speed. This motor speed then realizes a flywheel with kinetic energy to generate power corresponding to the desired input switch setting.

A proximity sensor 418 functioning as the feedback converter 360 is magnetically coupled to the motor M and detects the number of revolutions per unit time as the speed of the output shaft of the motor M (proximity sensor; for example, Red Lion Control Co., USA). MP25TA00). Proximity sensor 418 produces a sinusoidal output on lines 422,424. This output is 180 degrees out of phase and has a frequency proportional to the angular velocity or number of revolutions per minute of the rotating armature 386. Proximity sensor 4
The feedback signal from 18 passes through the DC bias network 426. This bias network 426 consists of resistors R23, R24 and a capacitor C7, the output of which is fed to the input of a zero-crossing detector 364 with a voltage comparator U6 (voltage comparator; eg Texas Instruments TLC372). The filtered feedback signal is a voltage comparator U6 to remove common mode noise.
Connected to the input of. And zero-cross detector 364
Provides on line 332 a relatively stable, noise-free feedback signal having a frequency that is directly proportional to the actual speed of the motor.

The phase detector 334 includes a tri-state phase detector 428 (eg, Motorola MC54 / 74HC4046A). The detector 428 produces an error signal on the output line 332 in response to the speed indicating frequency and the feedback frequency having a duty ratio as a function of the phase difference between the speed indicating reference frequency and the feedback frequency. Low-pass filter 33
8 is a diode matrix 430 and resistors R8 and R1
4, R15 and capacitor C2. Low pass filter 338 provides a DC voltage level at output 340 in response to an error signal on output 336 of phase detector 334.
The height of this voltage level is proportional to the duty ratio of the error signal. The voltage comparator 348 is the comparator U6.
It has a voltage comparator U2 similar to. This comparator U2 is the output 34 of the lamp generator 372.
6 in response to the ramp signal of 6 and the average error signal at the output 340 of the low pass filter 338, and provides a trigger pulse at output 350 to turn on the triac 321 in response to the average error signal crossing the ramp signal.

When the phases of the reference frequency and the feedback frequency match, the tri-state phase comparator 428
Is a tri-state output in the idle state. When the actual motor speed is slower than the desired motor speed, the phase of the reference frequency leads the phase of the feedback frequency, and the phase comparator 428 produces a negative signal in synchronization with the rising edge of the preceding reference frequency. Phase comparator 42
8 returns this negative polarity signal to the resting tri-state output in synchronization with the next rising edge of the delayed feedback frequency. Similarly, when the actual motor speed is faster than the desired speed, the phase of the feedback frequency leads the phase of the reference frequency, and the phase comparator 428 generates a positive polarity signal in synchronization with the rising edge of the reference frequency. The phase comparator 428 returns the positive polarity signal to the resting tri-state output in synchronization with the next leading edge of the delayed feedback frequency. Therefore, the tri-state phase comparator 428
Generates either a series of negative polarity pulse-like signals or positive polarity pulse-like signals in response to a phase of the feedback frequency that is behind or ahead of the phase of the speed reference frequency. The duration of this pulse-like signal is proportional to the magnitude of the phase difference or phase shift between the feedback frequency and the reference frequency.

For example, assuming that the motor M is rotating at a speed equal to the desired speed indicated by the speed instruction signal, the phase of the feedback frequency always has a constant relationship with the phase of the reference frequency. The phase comparator 428 is switched to a dormant tristate output and the switching diode network 430 is placed in a dormant state where the diodes are not tightly switched on or off. However, the charge on capacitor C2 provides a voltage to the input of voltage comparator U2, which provides a trigger pulse at output 350 when it crosses the ramp signal at the other comparator input. Trigger pulse is triac 3 during each half wave of AC signal.
21 is switched on and motor M is supplied with sufficient current to maintain the desired speed. At this time, the capacitor C2 may have a resistance R8,
It has a discharge path through R15 and diode D5.

It is assumed that the motor M slows down and the phase of the speed instruction reference frequency leads the feedback frequency. Thereupon, in response to the rising edge of the reference frequency, tristate phase comparator 428 produces a negative output signal at output 336. This output signal causes diode D2 to conduct, which causes current to pass through resistor R14 to diode D2.
3, turn off D4 and turn on diode D5. This condition of diode bridge 430 provides capacitor C2 with an emission path through resistors R8 and R15.
Capacitor C2 discharges relatively quickly, thereby lowering the voltage at output 340, which is the input of voltage comparator U2.

Therefore, when the actual motor speed drops below the desired motor speed, the tri-state phase comparator 428 produces an error signal having a series of pulse-like negative polarity signals which is passed through the low pass filter 338. Decrease the value of the generated average error signal. The reduced average error signal crosses the ramp signal earlier in the half cycle of the AC signal. Therefore, the voltage comparator U2 supplies the trigger pulse to the triac at an earlier time. The triac 321 intermittently delivers more current to the motor, which causes the actual motor speed to increase toward the desired motor speed. The next rising or positive edge of the feedback frequency will cause the tri-state phase comparator to return to the idle tri-state output. Such a process is iteratively performed for successive positive edges of the reference frequency and the feedback frequency while the reference frequency leads the feedback frequency.

In the other case, when the motor is rotating faster than the desired speed instruction, the feedback frequency leads the reference frequency in phase. Therefore, the output 336 of the tri-state phase comparator is switched to the signal of the positive polarity in response to the rising edge of the feedback frequency, that is, the edge of the positive polarity, and this signal is supplied to the diodes D2, D
Turn off 5 and turn on diodes D3 and D4. This causes a current to flow in the capacitor C2 via the resistor R14, so that the output lead 34
The voltage value of the 0 signal increases. In synchronization with the next rising edge of the feedback frequency, the tri-state phase comparator returns its output to the resting tri-state output signal level, thereby returning the diode bridge to rest and charging capacitor C2 via resistor R14. stop. The above process is repeated for each successive rising edge of the feedback frequency leading the rising edge of the reference frequency. Thus, when the actual motor speed exceeds the desired motor speed, the tri-state phase comparator 428 charging capacitor C2 provides a series of positive polarity pulse-like signals, which causes the voltage of the average error signal from low pass filter 338 to increase. Increase the value. As the level of the average error signal increases, the point where the voltage value of the ramp signal intersects will shift later in the generation period of the ramp signal. Therefore, the voltage comparator U
2 will supply the trigger pulse later in the ramp signal. This trigger pulse is the MO in the driver 374.
The S-type FET Q2 and the triac 321 are turned on later in the half cycle of the AC signal, thereby reducing the current flowing to the motor and reducing the motor speed.

Resistances R14 and R15 of the low-pass filter 338
The resistance value of the capacitor allows the discharge path to the capacitor C2 to discharge the capacitor relatively quickly as the motor slows down, thereby rapidly moving the switching point of the triac 321 to rapidly supply the current supplied to the motor. The value is set to increase. On the contrary, when the motor speed is higher than the desired speed, mechanical forces in the device such as friction and other losses cause the motor to decelerate naturally. Therefore, when the motor speed is too fast, the resistance value is selected so that the capacitor C2 is slowly charged. The low pass filter can also be considered as a digital / analog converter. This low pass filter
In response to the digital signal from the phase comparator 428 having a duty ratio indicating the phase error between the reference frequency and the feedback frequency, a DC voltage output which is the average value of the phase error is generated.

In use, switch 382 is used to power motor M. Switch 406,
408 is used to set input instructions corresponding to the desired output of the powered fastener. When using visual indicators or other things to show operator input instructions,
The motor speed, the operating power of the powered fasteners, the fastener dimensions used by the powered fasteners, etc., may be summarized as a set. For example, powered fasteners are 2 inches
If driving 3.5-inch nails, the motor speed would be selected from the range of 7,000 to 15,000 revolutions per minute. In the absence of a visual indicator, the desired amount of power is determined by several trial runs of fasteners. Once the desired input is set, this input will be maintained even when the fastener is switched off and restarted. When the drive cycle that drives the fasteners is activated, some of the kinetic energy is used to reduce the speed of flywheel 30 and motor M.
The phase detector 334 provides a large error signal, which is a negative polarity signal with a longer duration, and the triac 3
21 to supply the maximum current to the motor M. The capacitor C2 discharges rapidly and the conduction point of the triac 321 moves rapidly, increasing the current supplied to the motor. The motor control circuit 310 accelerates the motor to bring the motor and flywheel speed back to the maximum selectable speed within about 500 milliseconds. When the motor speed is increased so that there is no difference between the desired speed and the actual speed of the motor, the triac 321 changes the conduction point so that the average current applied to the motor M is also reduced. When the desired speed and the actual speed of the motor become equal, the reference frequency and the feedback frequency are synchronized such that the phase of the reference frequency is slightly behind the phase of the feedback frequency. The motor control circuit 310 is sensitive to the phase difference between the reference frequency or the feedback frequency, which is shorter than the cycle of the reference frequency or the feedback frequency. Therefore, since the motor speed can be controlled within the phase difference time domain, the motor control circuit 310 can control the motor speed within about ± 1% of the selected motor speed.

As one embodiment of the present invention, a special electric fastener driving machine capable of driving fasteners such as nails and staples at a desired cycle frequency is mentioned, but various other embodiments are possible. . As a simple motor to supply the desired flywheel speed, one flywheel and one motor control circuit are effectively used, and the motor is placed far from the steering wheel, and the drive shaft that distributes the rotational force to the flywheel is used. It is designed so that speed can be supplemented again despite using. In addition, the driving machine of the present invention is balanced by attaching a motor to the tip of the handle. The improved trigger connection combination facilitates normal operation of the driver. The present invention also provides a driver that can be used in various types of equipment.

The power supply 344 can be obtained from either a half-wave rectification or full-wave rectification AC signal. In any case, the zero-cross detector 368 is capable of responding to all zero-cross and delivers a zero-cross pulse with a frequency of 120 Hz. Selector switch 352 in speed instruction circuit 326
Can be configured in several ways. The selector switch 352 may be one switch having four outputs that can be decoded into ten choices. These four outputs may be connected to a binary-coded decimal / decimal converter that supplies ten voltage levels to the voltage controlled oscillator.
The feedback converter 360 is a device responsive to rotation of the motor M and may be any device capable of providing a periodic output signal at a frequency proportional to its motor speed. Comparator 348 and low pass filter 338 provide power switch 3 with a trigger pulse whose edge precedes the ramp signal in response to the phase difference between the speed indicating signal and the feedback signal.
It may be composed of other devices such as those supplied to 20.

The motor control circuit of the present invention has been described with respect to speed control of an AC / DC motor used to drive a flywheel housed in a handheld device. The motor control of the present invention has certain characteristics that are advantageous in the above-mentioned embodiment, but can be effectively used for other devices.

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[Procedure amendment]

[Submission date] May 31, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Added

[Correction content]

[Brief description of drawings]

FIG. 1 is a side view of a driving tool according to the present invention.

FIG. 2 is a partially cut front view of the driving machine as seen from the direction 2-2 in FIG.

FIG. 3 is an enlarged side view showing a part of the internal structure of the driving tool as seen from the direction 3A-3A in FIG.

FIG. 4 is a partially enlarged view showing a series of components of the driving device when the driving tool is viewed from the opposite side of FIG. 1.

5 is a cross-sectional view of the driving tool as seen from the direction 4-4 in FIG. 1, showing a non-operating state.

6 is a cross-sectional view of the driving tool as seen from the direction 4A-4A in FIG. 1, showing a state during operation.

FIG. 7 is a partial cross-sectional view when viewed from the direction 5-5 in FIG.

FIG. 8 is a partial cross-sectional view when seen from the direction 5A-5A in FIG.

FIG. 9 is an exploded view showing the flywheel, drum, clutch part ch, actuator part, trigger connecting part and the like of the driving machine shown in FIG.

10 is an enlarged perspective view of an actuator portion of the driving machine of FIG.

FIG. 11 is a partially enlarged view showing the operation sequence of the driving tool of FIG. 1.

FIG. 12 is a partially enlarged view showing an operation sequence of the driving tool of FIG.

FIG. 13 is a partially enlarged view showing an operation sequence of the driving tool of FIG. 1.

FIG. 14 is a partially enlarged view showing an operation sequence of the driving tool of FIG.

FIG. 15 is a partially enlarged view showing an operation sequence of the driving tool of FIG.

16 is a partially enlarged view showing an operation sequence of the driving tool of FIG. 1. FIG.

FIG. 17 is a partially enlarged view showing an operation sequence of the driving tool of FIG. 1.

FIG. 18 is a partially enlarged view showing the operation sequence of the driving tool of FIG. 1.

FIG. 19 is a block diagram showing a control system of a motor attached to the driving tool according to the present invention.

20 is a circuit diagram showing in more detail the components for controlling the motor of FIG.

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[Explanation of reference numerals] 10 fastener driving machine 11 housing 12 handle 15 magazine 18 nose 20 electric cord 22 drive shaft 25 pinion 26 spiral bevel tooth 27 spiral bevel tooth 30 flywheel 31 center line 35 trigger 40 driver 41 cylinder 42 coupling 43 Stopper 45 Drive Cable 49 Sleeve 50 Coil Spring 51 Cap 52 Return Cable 55 Conical Clutch 57 Drum 58 Ball Inner Dish 59 Bearing Cage 60 Ball Outer Dish 61 Presser Plate 62 Washer 63 Disc Spring 64 Ratchet Ring 66 Frustum 67 Shaft 68 Bearing 70 Truncated cone surface 71 friction member 73 cylindrical projection 74 spline 75 sleeve 76 spline 77 seal ring 79 spring 80 holding plate 81 inner side wall spline 82 winding surface 85 shoulder 86 Cylindrical surface 88 Ball bearing 89 Pocket 90 Pocket 91 Pocket 92 Pocket 93 Pocket 94 Pocket 95 Tail 96 Tail 97 Tail 98 Narrow Groove 99 Narrow Groove 100 Narrow Groove 101 Tail 102 Tail 103 Tail 104 Narrow Groove 105 Narrow Groove 106 Narrow Groove 109 Shield 111 Rib 112 Dog 113 Dog 114 Dog 115 Circumferential Side 117 Blade 118 Inner Blade 120 Projection 123 Cushion 124 Bracket 128 Safety Rod 129 Spring 130 First Engaging Claw 131 Shaft 132 Leaf Spring 135 Second Engaging Claw 136 Shaft 137 Long Hole 138 Spring 139 Bracket 140 Protrusion 145 Crank 146 Pin 147 Spring 148 First Link 149 Second Link 150 Pivot 151 Elongated Hole 152 Pin 153 Pivot 15 Actuating claw 157 Pivot 158 Spring 161 Third link 162 Inclined edge 163 Pin 166 Tail 316 AC power supply 320 Power supply 321 Triac 322 Trigger 326 Speed instruction circuit 330 Feedback circuit 334 Phase detector 338 Low-pass filter 342 Analog reference circuit 344 Comparator power supply 348 352 Selector switch 354 Voltage source 355 Display 358 Reference frequency oscillator 360 Feedback converter 364 Zero-cross detector 368 Zero-cross detector 372 Lamp oscillator (lamp generator) 374 Driver 382 On-off switch 384 Motor field winding 386 Motor armature 388 Brush 390 brush 392 motor field winding 396 common line 404 collector 406 acceleration button 408 deceleration button 410 de Digital potentiometer 418 Proximity sensor 426 DC bias network 428 Tri-state phase comparator 430 Diode matrix

Claims (19)

[Claims] 1. A motor control circuit for an AC / DC motor connected to an AC power supply, wherein the motor control circuit supplies a speed instruction signal of a reference frequency indicating a desired motor speed, and a motor rotation circuit. Means for supplying a feedback signal having a feedback frequency indicating the actual motor speed in response to, a means for repeatedly supplying a time-varying signal corresponding to each zero cross in response to an AC power supply signal, a speed instruction signal, a feedback signal And a means for generating a trigger pulse in response to the time-varying signal, the trigger pulse being generated at a time related temporally to each of the signals time-varying corresponding to the phase difference between the reference frequency and the feedback frequency, It is connected between the AC power supply and the motor and includes a trigger input that responds to the trigger pulse that controls the application of the AC power to the motor, and applies the AC power to the motor in response to the error signal. A motor control circuit comprising: a triac switch means for making a motor speed substantially equal to a desired motor speed. 2. The trigger pulse generating means further includes means for generating a phase error signal in response to the phase difference between the reference frequency and the feedback frequency in response to the speed instruction signal and the feedback signal, and a time-varying signal and a phase error. Motor in response to the signal for generating each trigger pulse in response to the phase error signal that is initiated at a time point temporally related to each time-varying signal. Control circuit. 3. An AC / DC motor that is driven by an AC power supply, has a TRIAC power switch and an analog reference circuit, and the TRIAC power switch is connected between the AC power supply and the motor to connect the AC signal to the motor. A motor control circuit having a trigger input for controlling application, wherein an analog reference circuit repetitively supplies a ramp signal that responds to an AC signal and restarts substantially at each zero crossing of the AC signal. An input switch circuit for supplying an input signal having a voltage corresponding to the motor speed, a voltage controlled oscillator connected to the input switch circuit for supplying a speed instruction signal having a reference frequency corresponding to the voltage of the input signal, and responsive to the motor rotation. And a feedback converter that supplies a feedback signal with a feedback frequency corresponding to the actual motor speed, and a speed instruction signal and a feedback signal. In response, a phase detector that supplies a phase error signal corresponding to the phase difference between the reference frequency and the feedback frequency, a low-pass filter that supplies an average phase error signal in response to the phase error signal, and an average phase error signal Correspondingly, each trigger pulse having a leading edge for each ramp signal is provided in response to each ramp signal, thereby applying an alternating current corresponding to the phase error signal to the motor, thereby providing a reference frequency and a feedback frequency. And a comparator that maintains the zero phase difference of, thereby making the actual motor speed substantially equal to the desired motor speed. 4. A triac power switch having a trigger input connected between an AC power supply and a motor for controlling application of AC to the motor, the triac power switch being substantially equal to a zero-cycle repetition period of the AC signal in response to the AC signal. A motor control circuit for a motor driven by an alternating current signal from an alternating current power source, which repeatedly starts a ramp signal having a duration synchronously with a zero cross, further comprising a reference each corresponding to its desired motor speed. A speed instruction circuit for selectively supplying one of a plurality of speed instruction signals having a frequency, a feedback circuit for supplying a feedback signal having a feedback frequency corresponding to the actual motor speed in response to motor rotation, and a triac power supply It is connected to the trigger input of the switch and is responsive to the ramp signal, one of several speed indicating signals, and the feedback signal. A trigger pulse is generated corresponding to the phase difference between the reference frequency and the feedback frequency, which causes the triac power switch to switch to apply an AC signal to the motor corresponding to the phase difference. A motor control circuit comprising: a comparator circuit that makes an actual motor speed substantially equal to a desired motor speed. 5. An input switch circuit for providing a speed indicating circuit with an input signal having a voltage representing one of a plurality of selectable desired motor speeds, and a plurality of speed indicating signals for inputting the input signal. The motor control circuit according to claim 4, further comprising a voltage controlled oscillator that supplies one having a corresponding reference frequency. 6. A phase detector, wherein the comparator circuit supplies a phase error signal having a duty ratio proportional to the phase difference between the reference frequency and the feedback frequency in response to the speed indicating signal and the feedback signal, and a ramp signal and a phase. The motor control circuit according to claim 4, further comprising: a pulse generator that supplies a trigger pulse each time a ramp signal is generated in response to an error signal. 7. The phase detector comprises a series of positive pulses indicative of a first phase difference between the speed indicating signal and the feedback signal and a series of negative pulses indicating a second phase difference between the speed indicating signal and the feedback signal. 7. The motor control circuit according to claim 6, wherein the motor control circuit is a tri-state phase comparator that supplies the pulse of the pulse. 8. The first phase difference is responsive to a feedback signal lagging the speed indicating signal and the second phase difference is provided responsive to a feedback signal leading the speed indicating signal. Item 7. The motor control circuit according to item 7. 9. The motor control circuit according to claim 6, wherein the comparator circuit includes a low-pass filter that supplies an average phase error signal in response to the phase error signal. 10. The motor control circuit according to claim 9, wherein the low-pass filter functions as a digital / analog converter. 11. The pulse generator comprises a comparator responsive to the ramp signal and the average phase error signal to provide a trigger pulse initiated in each ramp signal corresponding to the average value of the phase error signal. The motor control circuit according to claim 9, wherein: 12. The motor control circuit according to claim 11, wherein each trigger pulse has a pulse width determined corresponding to the phase error signal. 13. The speed indicator circuit comprises from about 7000 to about 1.
The motor control circuit according to claim 4, wherein one of a plurality of speed instruction signals indicating a desired speed of the motor in a range of 5,000 revolutions / minute is selectively supplied. 14. The motor control circuit of claim 4, wherein the comparator circuit provides a trigger pulse to the triac so that the actual motor speed is approximately equal to the desired motor speed within about 500 milliseconds. 15. The motor control circuit of claim 4, wherein the comparator circuit maintains the actual motor speed within approximately 1% of the desired motor speed. 16. A motor control circuit for controlling an AC / DC motor in response to an AC signal from an AC power supply, the motor control circuit comprising a plurality of reference frequencies representing one of a plurality of desired motor speeds. A speed instruction circuit that selectively supplies one of the speed instruction signals, a feedback circuit that supplies a feedback signal of a feedback frequency that represents the actual motor speed in response to motor rotation, and a plurality of speed instruction signals and feedback signals. In response to one, a comparator circuit that supplies a phase error signal corresponding to the phase difference between the reference frequency and the feedback frequency, and in response to an AC signal, repeatedly supplies a ramp signal synchronized with each zero-cross of the AC signal. Has an analog reference circuit and a frequency of occurrence determined by the ramp signal in response to the ramp signal and the phase error signal, and during each ramp signal corresponding to the phase error signal It has a pulse generator that supplies a series of trigger pulses to be started, and a trigger pulse that controls the switching of the triac power switch in response to the trigger pulse, thereby applying an AC signal to the motor in response to the error signal A motor control circuit comprising: a triac power switch connected between the AC power supply and the motor, thereby causing the actual motor speed to be approximately equal to one of the desired motor speeds. 17. A phase detector, wherein the comparator supplies a phase error signal having a duty ratio proportional to the phase difference between the reference frequency and the feedback frequency in response to the speed indicating signal and the feedback signal, and the ramp signal and the phase error. A pulse generator responsive to each occurrence of a ramp signal responsive to the signal and a pulse generator responsive to each occurrence of the ramp signal. 18. The phase detector comprises a series of positive pulses representing a first phase difference between the speed indicating signal and the feedback signal and negative pulses representing a second phase difference between the speed indicating signal and the feedback signal. 18. The motor control circuit according to claim 17, wherein the motor control circuit is a tri-state phase comparator that supplies the pulse of 1. 19. A motor control circuit for an AC / DC motor that responds to an AC signal from an AC power supply, comprising: a TRIAC power switch, and a speed instruction circuit for supplying an instruction signal having a reference frequency representing a desired motor speed. , A feedback circuit that supplies a feedback signal with a feedback frequency that represents the actual motor speed in response to the motor rotation, and starts corresponding to the phase difference between the reference frequency and the feedback frequency in response to the instruction signal and the feedback signal. Connected to the TRIAC power switch, which supplies a trigger pulse that causes the TRIAC power switch to switch to apply AC power corresponding to the phase difference to the motor, thus causing the actual motor speed to approximately equal the desired motor speed. And a comparator circuit, and a motor control circuit comprising: