JP2011236035A - Device for preventing overrun of movable member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for preventing overrun of a movable member which when the movable member goes beyond a predetermined moving range to move to the outside of the range because of abnormal operation or the like, cuts off a drive circuit to stop the movable member, and then releases the stop, thereby making it possible to easily perform inspection and repair, and maintenance of the movable member.SOLUTION: When a paper feeding table 1 (the movable member) abnormally rises, it pushes up a first cam 52, and a shaft 9 and a disk-like actuating member 53 supported by the shaft 9 rise. The actuating member 53 pushes up a lever 54a of an upper limit microswitch 54 to cut off a drive circuit 63 of the paper feeding table 1. Next, when a small-diameter part 52b of the first cam 52 is made to abut on the paper feeding table 1 by turning the first cam 52 by a hand, the shaft 9 and the actuating member 53 lower by an amount equivalent to a diameter difference between a large-diameter part 52a and the small-diameter part 52b, so that cutoff of the upper limit microswitch 54 is released. Investigation of a cause of abnormal rise is therefore easily performed by lowering the paper feeding table 1. If the paper feeding table 1 still rises after releasing the cutoff of the drive circuit, the shaft 9 and the actuating member 53 are pushed up again.

Description

  In the present invention, when a movable member that can move within a predetermined range tries to move beyond the predetermined range due to a malfunction or the like, the movable member cuts the drive circuit and stops the movable member to prevent damage to the parts. More specifically, in the sheet feeding device that separates and feeds the topmost sheet of the stack of sheets stacked on the sheet feeding table that can move up and down, the sheet feeding table is raised too much. The present invention relates to a sheet feeding device that prevents damage caused by collision with a separation mechanism or the like.

  In a paper feeding device that stacks paper bundles and separates and feeds one sheet from the top of the paper bundle, the paper feed stand is raised as the paper feed proceeds, and the top of the bundle is kept at a certain height. I keep it. Therefore, the paper feed table is movable in a predetermined range in the vertical direction. Such a movable member movable within a predetermined range is used in many mechanical devices for various purposes. In many cases, a sensor that detects a movable member that has arrived near the end of the movement range is provided so that the movable member does not move beyond a predetermined movement range. When this sensor detects the movable member, the drive source is controlled so as to stop the movable member so as not to move any further according to the detection signal.

  However, if the sensor cannot be stopped for some reason, such as a failure of the sensor, the movable member moves beyond the allowable range in the machine configuration, so that the component may be damaged due to interference with other members. Become. For this reason, when the movable member moves beyond the detection position of the sensor, an overrun prevention mechanism that cuts the drive circuit by pressing a micro switch or the like may be provided.

  The apparatus of Patent Document 1 is a sheet feeding device in which this overrun prevention mechanism is provided on a sheet feeding table that is a movable member. As shown in FIG. 19, the apparatus of Patent Document 1 adsorbs the uppermost sheet bundle 112 stacked on the paper feed tray 130 to the lower surface of the sheet adsorption / conveyance head 140 and causes the belt 145 to circulate. In order to keep the upper surface at a constant height even when the sheet bundle 112 is reduced, the sheet feeding table 130 can be moved up and down. Normally, the level sensor 173 detects the upper surface of the sheet bundle 112 or the paper feed stand 130, and stops the raising of the paper feed stand 130 in response to this detection.

  However, when the level sensor 173 continues to rise without stopping due to a failure or the like, the sheet suction conveyance head 140 is pushed up and rotated as shown in FIG. By this rotation, an upper limiter switch (not shown) is turned off, and the drive circuit of the paper feed tray 130 is disconnected. Since the operation of the upper limiter switch means that the level sensor 173 is not operating normally, repair work such as replacement of the level sensor 173 is required.

JP 2004-196539 A ([0010] to [0011] [0040], FIG. 2, FIG. 4, FIG. 5, etc.)

  In the apparatus of Patent Document 1, when the upper surface of the sheet bundle 112 pushes up the sheet adsorption / conveyance head 140 and the upper limiter switch is turned off, the sheet adsorption / conveyance head 140 adsorbs and conveys the sheet by removing the sheet bundle 112. Since the original position (the position in FIG. 19) is restored, the paper feed table 130 can be operated again. Therefore, the repair work may be performed after removing the sheet bundle 112 and lowering the sheet feed stand 130. However, in a state where the sheet bundle 112 is not stacked, if the upper limiter switch is turned off when the upper surface of the sheet feed table 130 pushes up the sheet adsorption transport head 140, the sheet feed table 130 cannot be moved. An operation for removing the paper feed tray 130 is required.

  When the movable member moves beyond the detection position of the sensor and the overrun prevention mechanism operates in this way, the drive circuit is disconnected as long as the movable member is in that position. Since it is necessary to remove the movable member, there is a problem that it takes time to recover and repair the cause of overrun.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a movable member overrun prevention device that can be easily recovered even when the overrun prevention mechanism is activated.

  An apparatus for preventing overrun of a movable member of the present invention, which has been made to solve the above problems, includes a movable member that can be moved between a first position and a second position by a drive source, and the first position and the second position. Driving the movable member when the movable member attempts to move beyond the first position or the second position and out of the range between the first position and the second position. An overrun prevention device for a movable member having an overrun prevention means for cutting the circuit and stopping the movable member. The overrun prevention means arrives at a position immediately before the movable member reaches the first position or the second position. When this happens, the drive circuit is cut to stop the movable member, and a release operation for releasing the drive circuit is enabled. After the release operation, the movable member is still moved in the same direction as before the drive circuit is cut. To the first or second position If, an over run prevention device of the movable member, characterized in that to stop the movable member by cutting the driving circuit again.

  According to the present invention, even when the overrun prevention device is activated once and the drive circuit of the movable member is disconnected, this disconnection can be released. Therefore, by moving the movable member in the direction opposite to the direction of overrunning after release, the cause of overrun can be investigated and repaired without removing the movable member, so that workability can be improved.

The overrun prevention means includes an engagement unit having a first engagement portion that engages with the movable member, and a second engagement portion that engages with a switch that disconnects the drive circuit. When the position immediately before reaching the first position or the second position is reached, the movable member and the first engaging portion are engaged to move the engaging unit in one direction, so that the second engaging portion is The release operation is an operation of moving the engagement unit in the other direction by changing the engagement state of the first engagement portion and releasing the engagement of the second engagement portion. It may be.

  A switch that disconnects the drive circuit does not make sense as a safety switch that prevents the movable member from interfering with other members and damaging the member if the operator can directly release the switch. According to this aspect, by interposing the engagement unit, the release operation can be performed by operating the first engagement portion even if the operator does not directly operate the second engagement portion engaged with the switch. It is. Therefore, the release operation can be performed while ensuring the function as the safety switch.

  A cover member that covers a predetermined range including the switch and the second engagement portion so that a user's hand does not touch the first engagement portion; and the first engagement portion is outside the range covered by the cover member. You may comprise. According to this aspect, the operator can directly operate the second engagement portion by the cover, and the release operation can be performed by operating the first engagement portion outside the range covered by the cover. Become.

  The engagement unit may be biased in a direction in which the first engagement portion is directed toward the movable member. According to this aspect, regardless of the direction in which the movable member engages with the first engagement portion, the movement of the engagement unit accompanying the engagement / release operation can be ensured.

  The first engagement portion is a cam surface of a cam supported by a cam shaft provided in the engagement unit, and when the movable member arrives at a position immediately before reaching the first position or the second position, The movable member engages with the large-diameter portion of the cam and moves the engagement unit in one direction, thereby engaging the second engagement portion with the switch and disconnecting the drive circuit. May be an operation of moving the engagement unit in the other direction by rotating the engagement position of the movable member to the small diameter portion of the cam and releasing the engagement of the second engagement portion with the switch. .

  According to this configuration, there is an advantage that the release operation can be performed only by performing a simple operation of rotating the cam.

  The engaging portion of the movable member with the cam may be formed in a flat surface, and the small-diameter portion of the cam may be formed as a D-cut portion obtained by linearly cutting a part of the disk.

  According to this aspect, in the release operation, the release operation can be facilitated because the cam is rotated until the planes of the movable member and the D-cut portion of the cam come into contact with each other.

  The movable member is movable in a vertical direction, and the first position and the second position are an upper limit position and a lower limit position, respectively, at which the movable member moves, and the overrun prevention means includes a movable member at an upper limit position. When it is going to rise beyond the range, the drive circuit of the movable member is cut, and the cam shaft may be provided horizontally.

  According to this configuration, the cam can be biased with respect to the movable member by its own weight, so that the apparatus can be configured more simply.

  When the movable member arrives at a position immediately before reaching the first position or the second position, the movable member and the engagement unit engage and engage with each other with a spacer provided on either one of them. By moving the unit in one direction, the drive circuit is disconnected by engaging the second engagement portion with the switch,

  In the release operation, the engagement unit is moved in the other direction by changing the engagement portion with the movable member or the engagement unit by sliding the spacer, and the engagement of the second engagement portion with the switch is released. It may be an operation. Alternatively, the release operation may be an operation of moving the engagement unit in the other direction by removing the spacer and releasing the engagement, and releasing the engagement of the second engagement portion.

  According to these configurations, the release operation can be performed with a simple operation of removing or moving the spacer.

  Therefore, the present invention has an effect that when the overrun prevention mechanism is activated, recovery and investigation / repair of the cause of overrun can be facilitated.

It is a front view which shows the paper feeding apparatus 90 to which the overrun prevention apparatus of the movable member which concerns on 1st Embodiment of this invention is applied. It is the side view seen from the left side of FIG. 2 is a block diagram relating to driving of a motor M. FIG. FIG. 6 is a diagram illustrating a state in the paper feeding device 90 in which the paper feeding platform 1 has reached a position immediately before the upper limit. 6 is a diagram illustrating a state after the first cam 52 is rotated in the paper feeding device 90. FIG. FIG. 6 is a diagram illustrating a state in which the paper feed tray 1 is released after reaching a position immediately before the upper limit and then lifted again to reach the upper limit position in the paper feed device 90. FIG. 6 is a diagram illustrating a state in the paper feeding device 90 where the paper feeding table 1 has reached a position immediately before the lower limit. 6 is a diagram illustrating a state after the second cam 55 is rotated in the paper feeding device 90. FIG. FIG. 6 is a diagram showing a state in the paper feeding device 90 where the paper feeding platform 1 is released after reaching a position immediately before the lower limit and then lowered again to reach the lower limit position. 4 is a front view of the sheet feeding device 90 including a cover member. FIG. FIG. 6 is a diagram showing a state in the paper feeding device 91 where the paper feeding platform 1 is below the upper limit immediately preceding position. FIG. 6 is a diagram illustrating a state in the paper feeding device 91 where the paper feeding table 1 has reached a position immediately before the upper limit. 6 is a diagram illustrating a state after the spacer 81 is slid in the sheet feeding device 91. FIG. FIG. 6 is a diagram illustrating a state in which the paper feed tray 1 is released after reaching a position immediately before the upper limit and then lifted again to reach the upper limit position in the paper feed device 91. FIG. 6 is a diagram illustrating a state in the paper feeding device 92 where the paper feeding platform 1 is below a position immediately before the upper limit. FIG. 6 is a diagram illustrating a state in the paper feeding device 92 where the paper feeding platform 1 has reached a position immediately before the upper limit. 6 is a diagram illustrating a state where a spacer 85 is removed from the paper feeding device 92. FIG. FIG. 6 is a diagram illustrating a state in which the paper feed tray 1 is released after reaching a position immediately before the upper limit and then re-raised and reaches the upper limit position in the paper feed device 92. It is a figure which shows the paper feeding apparatus which concerns on background art. It is a figure which shows the paper feeding apparatus which concerns on background art.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a front view showing a paper feeding device 90 to which an overrun prevention device for a movable member according to a first embodiment of the present invention is applied, and FIG. 2 is a side view seen from the left side of FIG. The sheet feeding device of the present invention separates the topmost sheet from the sheet bundle P and feeds it in the direction of arrow A (see FIG. 2). Hereinafter, the arrow A direction is referred to as the downstream side, and the opposite direction is referred to as the upstream side.

  Reference numeral 1 denotes a paper feed table on which a bundle of paper sheets P is stacked. The sheet feed table 1 can be moved up and down by a motor M (see FIG. 2) while keeping its upper surface horizontal. The rotation of the motor M is converted into a vertical motion of the sheet feed table 1 by an appropriate drive transmission mechanism (not shown) such as a gear rack. A suction head unit 2 is provided above the paper feed table 1.

  The suction head unit 2 includes four belts 3 provided in parallel in a direction perpendicular to the paper feeding direction (hereinafter referred to as the width direction) at an interval, and provided inside the four belts 3. A suction chamber 5 and a fan 6 provided above the suction chamber 5.

  The suction chamber 5 has a hollow rectangular parallelepiped shape that is long in the width direction, and is supported by the bracket 11. The bracket 11 is formed of a U-shaped sheet metal having both sides on the upper side and the width direction, and supports the suction chamber 5 on the inner side of the U-shape. A fan 6 is fixed to the upper surface of the bracket 11.

  The fan 6 has a suction port on the lower side, and an opening is provided on the upper surface of the bracket 11 and the suction chamber 5 according to the position of the suction port, so that the suction port of the fan 6 and the inside of the suction chamber 5 are connected. Communicate. Therefore, when the fan 6 is driven, air inside the suction chamber 5 is sucked, and a negative pressure is formed in the inner space of the suction chamber 5. Further, an opening is provided in the lower surface of the suction chamber 5 at an intermediate portion between the adjacent belts 3, and air is sucked from the opening. The uppermost sheet of the sheet bundle P is attracted to the lower surface of the belt 3 by this suction air.

  Pulleys 7 and 8 are provided before and after the suction chamber 5, and the belt 3 is placed between the pulleys 7 and 8. Pulleys 7 and 8 are fixedly supported on shafts 9 and 10, respectively. Plate-shaped frames 50 and 51 (not shown in FIG. 2) are provided on both sides in the width direction of the suction head unit 2 in a direction perpendicular to the paper feed table 1.

  The shaft 10 is rotatably supported by the frames 50 and 51, and a driving force is applied from a driving source (not shown). By this driving force, the belt 3 is driven so that its lower surface moves from the upstream side to the downstream side. The belt 3 circulates in a state where the separated sheet is adsorbed on the lower surface thereof, thereby sending out the adsorbed sheet to the downstream side.

  The shaft 10 is supported so as to fix its shaft position. The suction head unit 2 is rotatably provided with the shaft 10 as a fulcrum, and the right end of the shaft 9 in the width direction is formed on the frame 50. The long hole 50a is long in the vertical direction. In FIG. 2, the frames 50 and 51 are not shown, and only the position and shape of the elongated hole 50a are indicated by a one-dot chain line. Due to the weight of the suction head unit 2, the shaft 9 comes into contact with the lower end of the long hole 50 a, so that the lower surface of the belt 3 of the suction head unit 2 is stationary at a position parallel to the paper feed table 1.

  The fan 6 further has a discharge port on the left side in FIG. 1 (hereinafter referred to as “the left side in the width direction”), and an air passage 12 is provided in communication with the discharge port. As shown in FIG. 1, the air passage 12 extends from the fan 6 to the left in the width direction, changes its direction downward on the left side in the width direction of the bracket 11, and further on the lower surface side of the bracket 11 to the right side in FIG. The direction is changed to “right side”, and the air discharge hole 13 a formed in the side end guide 13 communicates. The side end guide 13 is provided on the left side in the width direction of the sheet feed table 1.

  Further, a front end guide 14 is provided on the downstream side of the paper feed tray 1. The sheet bundle P is stacked on the sheet feed table 1 so that the left end surface in the width direction abuts on the side end guide 13 and the downstream end surface abuts on the front end guide 14. In FIG. 2, the fan 6, the air passage 12, and the side end guide 13 are not shown, and only the position of the air discharge hole 13a is shown by a one-dot chain line. The air discharged from the fan 6 is discharged from the air discharge hole 13a through the air passage 12. Since the discharged air is sent between the sheets at the downstream end of the sheet bundle, the sheet bundle is spread. Note that the air discharge port may be disposed so as to blow toward the downstream end face of the sheet bundle.

 In the present embodiment, the fan 6 serves as both a suction source for sucking sheets and an air discharge source for spreading the bundle of sheets. However, separate fans may be provided.

  A level sensor 15 is provided on the upstream side of the suction head unit 2. The level sensor 15 includes a lever 16, a support shaft 17 that rotatably supports the lever 16, an optical sensor S1, and a support bracket 19. When the paper feed tray 1 loaded with the sheet bundle P is raised, the upper surface of the sheet bundle P comes into contact with the lower end of the lever 16 and pushes up the lever 16. The lever 16 rotates clockwise about the support shaft 17. When the lever 16 closes the optical axis of the optical sensor S1 by this rotation, the upper surface of the sheet bundle P is kept at a fixed position by stopping the ascent of the sheet feed table 1.

  The front end guide 14 is a front end guide portion 14a that guides the front end of the sheet bundle P, and a lower surface guide portion 14b that is bent from the upper end of the front end guide portion 14a to the downstream side and guides the lower surface of the fed paper. Have Openings 14c and 14d are provided at positions close to the bending line of the lower surface guide 14b. The openings 14c and 14d have the same shape and are spaced apart from each other in the width direction, and are each elongated in the width direction.

  A first separation member 20 and a second separation member 30 are provided through the openings 14c and 14d, respectively.

  The first separation member 20 is formed between the second belt 3 from the left side and the third belt 3 from the left side in FIG. 1 and is long in the vertical direction and can be accommodated in an intermediate portion between adjacent belts 3. It is a plate-shaped member which has. The second separation member 30 is provided so that the upper end contacts the leftmost belt 3 in FIG.

  As shown in FIG. 2, the second separation member 30 is fixedly supported on the lower support member 31 by sticking or screwing. A rack 32 is formed below the support member 31 and meshes with the pinion gear 33. The user can rotate the shaft (not shown) of the pinion gear 33, or can be driven and rotated by a motor or the like (not shown) so that the height of the first separation member 30 can be adjusted. Although not appearing in FIG. 1, the height of the first separating member 20 can be adjusted by the same configuration.

  When the uppermost sheet of the sheet bundle P is attracted to the lower surface of the belt 3, usually only the uppermost sheet is attracted. However, two or more sheets may be adsorbed, for example, when the suction air is too strong, the paper quality tends to stick to each other when stacked, or the environment is likely to generate static electricity. In this case, if the belt 3 is circulated as it is, double feeding for feeding two or more sheets at a time occurs.

  However, at the time of the feeding, the first separating member 20 and the second separating member 30 prevent the next sheet P2 from moving forward, so that only the uppermost sheet P1 can be fed. The material of the first and second separation members 20 and 30 is preferably an elastic material such as urethane rubber or artificial woven fabric.

  Below the second separation member 30, an opening 14e is formed in the front end guide portion 14a, and a sheet feed table sensor S2 is provided on the downstream side of the opening 14e. The sheet feed table sensor S2 is a reflective optical sensor that emits light horizontally toward the upstream side, and detects whether the sheet feed table 1 is on the optical axis of the sheet feed table sensor S2 through the opening 14e. The position detected by the sheet feeding table sensor S2 is the initial position. When the sheet feeding is completed and the sheet on the sheet feeding table 1 runs out, or when the sheet feeding device stops in error, The sheet feed table 1 is lowered and stops at the initial position detected by the sheet feed table sensor S2.

  A first cam 52 is rotatably supported by the shaft 9 above the vicinity of the right end in the width direction of the sheet feed table 1. The first cam 52 has a large-diameter portion 52a that is an outer peripheral surface of the disk, and a small-diameter portion 52b (D-cut portion) in which a part of the outer peripheral surface is cut out linearly. Since the small diameter portion 52b is lighter than the large diameter portion 52a, the small diameter portion 52b faces upward due to the weight of the large diameter portion 52a.

  A disc-shaped operating member 53 is supported on the shaft 9 on the opposite side of the first cam 52 with the frame 50 in between. An upper limit micro switch 54 is provided above the operation member 53 and fixed to the frame 50. In the upper limit micro switch 54, the lever 54a is supported on the shaft 54b, and the switch is turned off when the right end of the lever 54a is lifted upward in FIG. The vicinity of the right end of the lever 54 a is provided in the upper part with a slight gap from the top of the outer peripheral surface of the operating member 53.

  A second cam 55 is provided below the right end of the paper feed tray 1 in the width direction. The second cam 55 has a large-diameter portion 55a that is the outer peripheral surface of the disk and a small-diameter portion 55b (D-cut portion) in which a part of the outer peripheral surface is cut out linearly.

  The second cam 55 is fixedly supported at one end of a shaft 56, and the shaft 56 passes through a long hole 50 c that is formed in the frame 50 so as to be elongated vertically, and extends to the outside of the frame 50. The other end of the shaft 56 is rotatably supported with respect to the lever 58 outside the frame 50. In FIG. 2, the frame 50 is not shown, and only the position and shape of the elongated hole 50c are indicated by a one-dot chain line.

  The lever 58 is rotatably supported by a shaft 59 erected on the frame 50, and is urged by a spring 60 in a direction to rotate clockwise about the shaft 59 in FIG. Abutting against a stopper 61 erected on the frame 50, the lever 58 is stationary at a substantially horizontal position.

  An operating member 57 is fixedly supported on the shaft 56 between the lever 58 and the frame 50. It is long in the width direction. The actuating member 57 is formed in a disc shape, and has a thinned portion 57a in the upper half of the disc in FIG. Due to the difference in mass between the portion with and without the thinned portion 57a, the thinned portion 57a faces upward and is stationary.

  Further, the small-diameter portion 55b of the second cam 55 and the lightening portion 57a of the operating member 57 are respectively fixed to the shafts 56 so as to be opposite to each other. The second cam 55 is lighter on the small-diameter portion 55b side than the large-diameter portion 55a, but the mass difference is smaller than the mass difference between the side where the actuating member 57 is thinned and the side where the operating member 57 is not. Is stationary with the small diameter portion 55b facing downward.

  A lower limit micro switch 62 is provided below the operation member 57 so as to be fixed to the frame 50. In the lower limit micro switch 62, the lever 62a is supported by the shaft 62b, and the switch is turned off when the right end of the lever 62a is pushed downward in FIG. The vicinity of the right end of the lever 62a is provided below the outer peripheral surface of the operating member 57 with a slight gap.

  FIG. 3 is a block diagram relating to driving of the motor M. The upper limit micro switch 54 and the lower limit micro switch 62 are connected to a drive circuit 63 for causing a drive current to flow to the motor M that drives the paper feed tray 1, and are driven when the upper limit micro switch 54 or the lower limit micro switch 62 is turned off. The circuit 63 is cut off.

  The driver circuit 64 is connected to the CPU 65, and the CPU 65 is further connected to the optical sensor S1 and the paper feed table sensor S2 via a communication line 66. Accordingly, the CPU 65 can drive and control the motor M with reference to the detection signals sent from the optical sensor S1 and the paper feed table sensor S2.

  The CPU 65 is further connected to an operation panel 67 so that information input by the user can be received from the operation panel 67. The operation panel 67 is provided with, for example, an ascending button and a descending button for the sheet feeding table 1, and transmits button operation signals to the CPU 65, and the CPU 65 raises and lowers the sheet feeding table 1 according to the operation signals. That is, the paper feed table 1 can be raised and lowered by a user's button operation.

A paper feeding operation of the paper feeding device 90 will be described.
When the sheet bundle P is loaded on the paper feed tray 1 and the apparatus is started, a start signal is sent to the CPU 65, and the CPU 65 sends a signal to the driver 64 so as to raise the motor M. As a result, the paper feed stand 1 rises. To do. The upper surface of the sheet bundle P pushes up the lever 16 of the level sensor 15, and this lever 16 is detected by the optical sensor S1. When this detection signal is sent to the CPU 65, the CPU 65 sends a signal to the driver 64 so as to stop the motor M, and the paper feed table 1 is raised and stopped.

  Next, the fan 6 is activated, air is blown out from the air discharge port 13a through the air passage 12, air is sent between the sheets of the sheet bundle P, and the downstream end portion of the sheet bundle P is floated. At the same time, air is sucked through the opening formed in the lower surface of the suction chamber 5 at the intermediate portion between the belt 3 and the belt 3 on the lower surface of the suction head unit 2, and the uppermost sheet of the sheet bundle P is adsorbed on the lower surface of the belt 3. To do.

  Next, the belt 3 is driven to go around, and one adsorbed sheet is sent to the downstream side. At this time, the first and second separation members 20 and 30 prevent the second sheet P2 from being sent out. When the fed paper is gripped by a conveyance roller or the like (not shown) on the downstream side, the circumferential driving of the belt 3 stops. The fed sheet is conveyed further downstream by a conveying roller or the like, and the next sheet is attracted to the lower surface of the belt 3, and the belt 3 is driven again at an appropriate timing to send out the next sheet. Thus, the sheets of the sheet bundle P are continuously sent out one by one.

  When the sheet feeding is continued in this manner and the upper surface level of the sheet bundle P is lowered, the tip of the lever 16 is lowered and moved out of the detection range of the optical sensor S1, and a signal indicating that is sent from the optical sensor S1. Is sent to the CPU 65. In response to this, the CPU 65 sends a signal to the driver circuit 64 so as to drive the motor M in the direction to raise the paper feed table 1, and the motor M rotates to raise the paper feed table 1.

  When the lever 16 is detected again by the optical sensor S1 due to the raising of the sheet feed table 1, this detection signal is sent to the CPU 65. In response to this, the CPU 65 drives the motor M in the direction to lower the sheet feed table 1. Then, a signal is sent to the driver circuit 61, the motor M is stopped, and the paper feed table 1 is stopped. By repeating this operation, the height of the uppermost surface of the sheet bundle P is kept at a fixed position.

  When a stop operation such as pressing the stop button is performed while the sheet feeding is continuously repeated, the feeding of the sheet being fed at that time is completed, and then the fan 6 is stopped and the sheet feeding table 1 is lowered.

  When the sheet feeding table 1 reaches the initial position, the sheet feeding table 1 is detected by the sheet feeding table sensor S2, and this detection signal is sent to the CPU 65. Then, since the CPU 65 sends a signal to the driver circuit 64 to stop the motor M, the motor M stops and the paper feed tray 1 stops at the initial position. Even when all the paper feeds are completed and the paper on the paper feed tray 1 has been used up, it is detected by an appropriate paper no-detection means (not shown). After that, the fan 6 is stopped and the paper feed table 1 is lowered to the initial position.

Next, the operation of the overrun prevention device applied to the paper feeding device 90 will be described.
First, the operation of the upper limit side overrun prevention means for preventing the sheet feed stand 1 (movable member) from rising beyond the upper limit position (first position) will be described.

  When the sheet feed table 1 (movable member) is raised and its upper surface pushes up the lever 16 of the level sensor 15, the lever 16 blocks the optical axis of the optical sensor S1. If it is normal, the detection signal of the optical sensor S1 is sent to the CPU 65, a stop signal is sent from the CPU 65 to the motor M, and the paper feed tray 1 stops.

  However, when there is some abnormality such as failure of the optical sensor S1 and the detection signal cannot be sent to the CPU 65, the paper feed tray 1 continues to rise. If it continues to rise, the ascending force still acts by interfering with other members, so that the members are deformed or broken. In order to prevent this, the sheet feeding device 90 is provided with upper limit side overrun prevention means.

  The upper limit side overrun prevention means includes means for detecting that the paper feed tray 1 has reached a position immediately before the upper limit, means for cutting the drive circuit of the paper feed stand 1 in response to this detection, A suction head having means for performing an operation for canceling the cutting, and a means for detecting when the sheet feeding base 1 further rises and reaches the upper limit after the release, and again disconnects the drive circuit of the paper feeding base 1; The unit 2 includes an operation member 53, an upper limit micro switch 54, a drive circuit 63, and a first cam 52.

  FIG. 4 is a diagram illustrating a state in which the paper feed tray 1 has reached the position immediately before the upper limit. Even if the optical sensor S1 detects the lever 16, if the sheet feed table 1 continues to rise, the sheet feed table 1 reaches the position immediately before the upper limit. As shown in FIG. 4, at the position immediately before the upper limit, the upper surface of the sheet feed table 1 engages with the large-diameter portion 52a of the first cam 52 (first engaging portion) to support the first cam 52. The shaft 9 and the suction head unit 2 supporting the shaft 9 are pushed up. The pushed-up suction head unit 2 rotates upward with the shaft 10 as a fulcrum.

  Further, together with the shaft 9 pushed up, the operating member 53 supported by this shaft 9 also rises, and its outer peripheral surface engages with the right end of the lever 54a of the upper limit micro switch 54 (second engaging portion), and pushes up. The upper limit micro switch 54 is disconnected. Then, since the drive circuit 63 is disconnected, the paper feed table 1 stops regardless of the presence or absence of a stop signal from the CPU 60, and further rises and interferes with other members to cause deformation and destruction. prevent.

  Accordingly, the shaft 9, the first cam 52 and the operating member 53 supported by the shaft 9, the first engagement portion that engages with the sheet feed base 1 that is a movable member, and the second engagement that disconnects the micro switch 54. It functions as an engagement unit containing a part.

  If the paper feed tray 1 remains at the position shown in FIG. 4, it becomes an obstacle to the investigation and repair of the cause of the abnormal rise, for example, the inspection and repair of the level sensor 15. However, if the drive circuit 63 remains disconnected, the sheet feed table 1 cannot be moved unless the drive circuit 63 is released. Therefore, the drive circuit 63 must be disconnected. This release will be described below.

  The release operation is performed by operating the first cam 52 and changing the engagement state of the engagement portion (first engagement portion) between the first cam 52 and the sheet feed table 1 to move the operating member 53 together with the shaft 9. By lowering, the engagement (second engagement portion) between the operating member 53 and the lever 54a is released.

  Specifically, in a state where the paper feed base 1 pushes up the first cam 52 and the operating member 53 cuts the upper limit micro switch 54, the first cam 52 is rotated so that the small diameter portion 52b is downward. Let In the present embodiment, the first cam 52 is manually rotated by pinching by hand or the like, but may be electrically rotated using some drive mechanism.

  FIG. 5 is a view showing a state after the first cam 52 is rotated. As shown in FIG. 5, when the small-diameter portion 52b is rotated downward, the D-cut surface of the small-diameter portion 52b comes into contact with the upper surface of the paper feed table 1, that is, from the state of FIG. The engagement state changes. By this operation, the shaft 9 supporting the first cam 52 is lowered by the diameter difference between the small diameter portion 52b and the large diameter portion 52a, so that the operating member 53 is also lowered.

  Since the operating member 53 is separated from the lever 54a of the upper limit micro switch 54, the lever 54a rotates in the clockwise direction in the figure, and the cutting of the upper limit micro switch 54 is released. Then, the drive circuit 63 is connected again, and the sheet feed table 1 can be moved up and down by a signal from the CPU 65. At this time, when an operation such as pressing a button for lowering the paper feed tray 1 is performed from the operation panel 67, this operation signal is input to the CPU 65, and the CPU 65 lowers the paper feed tray 1 in response to this operation signal. Then, a signal is sent to the driver circuit 64. As a result, the paper feed tray 1 is lowered, and it becomes easy to perform inspection repair and maintenance such as inspection and replacement of the level sensor 15.

  When the disconnection of the drive circuit 63 is released by operating the first cam 52, the sheet feed table 1 may further rise depending on the cause of the abnormal increase such as an abnormality of the motor M. Then, the sheet feed stand 1 pushes up the small diameter portion 52 b of the first cam 52.

  FIG. 6 is a diagram illustrating a state in which the sheet feeding table 1 is released after reaching the position immediately before the upper limit, and then lifted again to reach the upper limit position. When the sheet feeding base 1 further rises and pushes up the small diameter portion 52b of the first cam 52, the operating member 53 rises again and cuts the upper limit micro switch 54. That is, since the drive circuit 63 is disconnected, the paper feed tray 1 stops regardless of the presence or absence of a stop signal from the CPU 65. Therefore, even if the sheet feeding table 1 further rises after the release, it is possible to prevent deformation and destruction due to interference with other members.

  The upper limit position is a position that should not be raised any more in order to avoid interference between the sheet feed table 1 and other members. In the sheet feeding device 90 of the present invention, the position immediately before this upper limit position (slightly (Lower position), the upper limit microswitch 54 is once disconnected to disconnect the drive circuit 63, and further, there is a means for releasing the disconnection. If the paper feed tray 1 further rises and reaches the upper limit position after the release, the upper limit micro switch 54 is disconnected again to disconnect the drive circuit 63, thereby reliably avoiding interference with other members. it can.

  Next, the operation of the lower limit side overrun prevention means for preventing the sheet feed stand 1 (movable member) from descending beyond the lower limit position (second position) will be described.

  When the sheet feeding table 1 (movable member) is lowered to the initial position and detected by the sheet feeding table sensor S2, this detection signal is normally sent to the CPU 65, and a stop signal is sent from the CPU 65 to the motor M. The paper feed tray 1 stops.

  However, if there is some abnormality such as failure of the paper feed table sensor S2 and the detection signal cannot be sent to the CPU 65, the paper feed platform 1 continues to descend. If the descent continues further, the descent force still acts by interfering with other members, so that deformation or destruction of the members occurs. In order to prevent this, the sheet feeding device 90 is provided with lower limit side overrun prevention means.

  The lower limit side overrun prevention means includes means for detecting that the paper feed tray 1 has reached a position immediately before the lower limit, means for cutting the drive circuit of the paper feed stand 1 in response to this detection, A means for performing an operation for canceling the cutting, and a means for detecting when the sheet feeding table 1 is further lowered and reaches the lower limit after the release, and again disconnects the drive circuit of the sheet feeding table 1; It comprises a cam 55, a shaft 56, an operating member 57, a lever 58, a shaft 59, a spring 60, a stopper 61, a lower limit micro switch 62, and a drive circuit 63.

  FIG. 7 is a diagram illustrating a state in which the paper feed tray 1 has reached the position immediately before the lower limit. Even if the sheet feed table sensor S2 detects the sheet feed table 1, if the sheet feed table 1 continues to descend, the sheet feed table 1 reaches the position immediately before the lower limit. As shown in FIG. 7, at the position immediately before the lower limit, the lower surface of the sheet feed table 1 is engaged with the large diameter portion 55a of the second cam 55 (first engaging portion) to support the second cam 55. And the lever 58 supporting the shaft 56 is pushed down. The pushed lever 58 rotates downward with the shaft 59 as a fulcrum.

  In addition to the depressed shaft 56, the operating member 57 supported by the shaft 56 also descends, and its outer peripheral surface engages with the right end of the lever 62a of the lower limit micro switch 62 (second engaging portion), and is depressed. The lower limit micro switch 62 is disconnected. Then, since the drive circuit 63 is disconnected, the sheet feed table 1 stops regardless of the presence or absence of a stop signal from the CPU 65, and further descends and interferes with other members to cause deformation and destruction. prevent.

  Therefore, the shaft 56, the second cam 55 and the operating member 57 supported by the shaft 56, the first engagement portion that engages with the sheet feed table 1 that is a movable member, and the second engagement that disconnects the micro switch 62. It functions as an engagement unit containing a part.

  If the paper feed tray 1 remains at the position shown in FIG. 7, it becomes an obstacle to investigate and repair the cause of the abnormal lowering, for example, inspection and repair of the paper feed stand sensor S2. Must be released. This release will be described below.

  The release operation is performed by operating the second cam 55 to change the engagement state of the engagement portion (first engagement portion) between the second cam 55 and the paper feed table 1, thereby moving the operating member 57 together with the shaft 56. By raising, the engagement (second engagement portion) between the actuating member 57 and the lever 62a is released.

  Specifically, the second cam 55 is rotated so that the small-diameter portion 55b faces upward in a state where the paper feed base 1 pushes down the second cam 55 and the operating member 57 cuts the lower limit micro switch 62. Let In the present embodiment, the second cam 55 is manually rotated by pinching by hand or the like, but may be electrically rotated using some drive mechanism. FIG. 8 is a view showing a state after the second cam 55 is rotated. As shown in FIG. 8, when the small-diameter portion 55b is turned up, the D-cut surface of the small-diameter portion 55b comes into contact with the lower surface of the paper feed table 1, that is, from the state of FIG. The engagement state changes.

  The lever 58 is biased so as to be pulled upward by a spring 60. Therefore, due to the change in the engagement state, the shaft 56 supporting the second cam 55 is raised by the difference in diameter between the small diameter portion 55b and the large diameter portion 55a, so that the operating member 57 is also raised.

  Further, since the urging force by the spring 60 acts in a state where the D cut surface of the small diameter portion 55b and the lower surface of the paper feed table 1 are in contact with each other, the shaft 56 due to the mass difference in the circumferential direction by the lightening portion 57a of the operating member 57 Is prevented from rotating.

  Since the operating member 57 is separated from the lever 62a of the lower limit micro switch 62, the lever 62a rotates in the clockwise direction in the drawing, and the cutting of the lower limit micro switch 62 is released. Then, the drive circuit 63 is connected again, and the sheet feed table 1 can be moved up and down by a signal from the CPU 65.

  At this time, if an operation such as pressing a button for raising the paper feed tray 1 is performed from the operation panel 67, this operation signal is input to the CPU 65, and the CPU 65 raises the paper feed tray 1 in response to this operation signal. Then, a signal is sent to the driver circuit 64. As a result, the sheet feed table 1 rises, and it becomes easy to perform inspection repair and maintenance such as inspection and replacement of the sheet feed table sensor S2.

  When the second cam 55 is operated to release the disconnection of the drive circuit 63, the paper feed table 1 may be further lowered depending on the cause of abnormal lowering such as an abnormality of the motor M. Then, the sheet feed table 1 pushes down the small diameter portion 55 b of the second cam 55. FIG. 9 is a diagram illustrating a state in which the paper feed tray 1 is released after reaching the position immediately before the lower limit, and then lowered again to reach the lower limit position.

  When the sheet feeding base 1 further descends and pushes down the small diameter portion 55b of the second cam 55, the operating member 57 descends again to cut the lower limit micro switch 62. That is, since the drive circuit 63 is disconnected, the paper feed tray 1 stops regardless of the presence or absence of a stop signal from the CPU 65. Therefore, even if the paper feed tray 1 further descends after the release, it is possible to prevent deformation and destruction due to interference with other members.

  The lower limit position is a position that should not be lowered further in order to avoid interference between the paper feed tray 1 and other members. In the paper feeding device 90 of the present invention, the position immediately before this lower limit position (slightly In the upper position), the lower limit micro switch 62 is once disconnected to disconnect the drive circuit 63, and further, there is a means for releasing this disconnection. If the paper feed tray 1 further lowers after reaching the lower limit position, the lower limit micro switch 62 is disconnected again to disconnect the drive circuit 63, thereby reliably avoiding interference with other members. it can.

  FIG. 10 is a front view showing a sheet feeding device 90 to which the movable member overrun prevention device according to the first embodiment of the present invention is applied, and is a front view including a cover member (in FIGS. 1 and 2). (The cover member is not shown). As shown in FIG. 10, the outer sides of the frames 50 and 51 are covered with cover members 70 and 71, respectively. The cover members 70 and 71 are plate-like members made of sheet metal, resin or the like, and surround the operating members 53 and 57, the upper limit micro switch 54, the lower limit micro switch 62, the lever 58 and the like outside the frames 50 and 51. Provided so that these members cannot be touched directly.

  On the other hand, since the first cam 52 and the second cam 55 are located outside the range covered by the cover member, whether the paper feed table 1 has arrived immediately before the upper limit position or the lower limit position is exceeded. When the micro switch 54 or the lower limit micro switch 62 is disconnected, the first cam 52 and the second cam 55 can be manually operated to release the disconnected switch. Since the switch 54 and the lower limit micro switch 62 cannot be operated, the function as a safety switch is ensured.

  In this embodiment, the overrun prevention means is provided on both the upper limit side and the lower limit side. However, the overrun prevention means may be provided only on either the upper limit side or only the lower limit side. Of course.

(Second Embodiment)
A sheet feeding device 91 to which a movable member overrun prevention device according to a second embodiment of the present invention is applied will be described. The sheet feeding device 91 according to the second embodiment is different from the sheet feeding device 90 according to the first embodiment in the overrun prevention device at the upper limit.

  FIGS. 11 to 14 show the overrun prevention means on the upper limit side of the sheet feeding device 91 according to the second embodiment. The drive circuit is once cut at a position immediately before the sheet feed table 1 as a movable member reaches the upper limit position. FIG. 8 is a diagram illustrating an operation when a release operation is performed thereafter and an operation when the upper limit position is reached by moving upward after the release operation. Members having the same functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 11 is a diagram illustrating a state in which the paper feed tray 1 in the paper feed device 91 is below the position immediately before the upper limit. As shown in FIG. 11, the paper feeding device 91 does not have the first cam 52 of the paper feeding device 90 to which the overrun prevention device for the movable member according to the first embodiment is applied, and is provided with a spacer 81 instead. Yes.

  The spacer 81 is provided on the upper surface of the paper feed tray 1 and is slidable on the upper surface in the horizontal direction in the figure. On the downstream side of the spacer 81, a stopper 82 is erected on the paper feed table 1, and a spring 83 is interposed between the spacer 81 and the paper feed table 1 so that the spacer 81 faces the stopper 82. By urging, the spacer 81 comes into contact with the stopper 82 and is stationary.

  Further, the portion directly below the shaft 9 on the upper surface of the spacer 81 has a first shaft housing portion 81a formed in a circular arc shape, and on the downstream side of the first shaft housing portion, a first shaft housing portion and A second shaft housing part is provided at a position that is similar in shape and lower than the first shaft housing part. A handle portion 81 c protruding upward is provided at the upstream end portion of the spacer 81.

  FIG. 12 is a diagram illustrating a state in which the paper feed tray 1 in the paper feed device 91 has reached a position immediately before the upper limit. When the sheet feed table 1 continues to rise due to an abnormality of the optical sensor S 1, the sheet feed table 1 reaches a position immediately before the upper limit, and the shaft 9 comes into contact with and is accommodated in the first shaft accommodating portion 81 a of the spacer 81. Then, the suction head unit 2 supporting the shaft 9 is pushed up.

  Then, since the suction head unit 2 rotates upward with the shaft 10 as a fulcrum, the operating member 53 supported by the shaft 9 also rises and cuts the upper limit micro switch 54. Then, since the drive circuit 63 is disconnected, the sheet feed table 1 stops regardless of the presence or absence of a stop signal from the CPU 60, and prevents deformation and destruction of the members.

  Accordingly, the engagement unit includes the first engagement portion in which the shaft 9 and the operation member 53 engage with the spacer 81 (movable member) that moves together with the sheet feed table 1 and the second engagement portion that cuts the micro switch 54. Function as.

  Next, the disconnection of the drive circuit 63 is released. The release operation is performed by operating the spacer 81 to change the engagement state of the engagement portion (first engagement portion) between the spacer 81 and the shaft 9, thereby lowering the operation member 53 together with the shaft 9. And the lever 54a is released (second engagement portion).

  Specifically, the handle 81c of the spacer 81 is pinched by hand and slid to the upstream side. FIG. 13 is a view showing a state after the spacer 81 is slid.

  As shown in FIG. 13, the shaft 9 is detached from the first shaft housing portion 81 a and is brought into contact with and housed in the second shaft housing portion 81 b. Then, since the shaft 9 is lowered due to the height difference between the first shaft housing portion 81a and the second shaft housing portion 81b, the operating member 53 is also lowered. The operating member 53 is separated from the lever 54a of the upper limit micro switch 54, and the cutting of the upper limit micro switch 54 is released. Then, the drive circuit 63 is connected again, and the paper feed table 1 can be moved up and down by a signal from the CPU 65. Can be lowered, facilitating inspection, repair and maintenance.

  Even when the spacer 81 slides downstream due to the action of the spring 83 when the shaft 9 is lowered from the second shaft housing portion 81b by lowering the sheet feed table 1, the shaft 9 contacts the step 81d. The shaft 9 is prevented from being lifted again. Further, while the spacer 81 and the shaft 9 are separated from each other, the first shaft housing portion 81a is always located directly below the shaft 9 by the spring 83, so that the paper feed table 1 is raised and the upper limit position is reached. When the position reaches the immediately preceding position, the shaft 9 is always brought into contact with and accommodated in the first shaft accommodating portion 81a.

  FIG. 14 is a diagram illustrating a state in which the paper feed table 1 is lifted again and reaches the upper limit position after the upper limit microswitch 54 is released by operating the spacer 81. When the sheet feed table 1 is further raised, the shaft 9 is pushed up while being in contact with and housed in the second shaft housing portion 81b. Then, the operating member 53 is raised again and the upper limit micro switch 54 is disconnected. That is, since the drive circuit 63 is disconnected, the paper feed tray 1 stops regardless of the presence or absence of a stop signal from the CPU 65. Therefore, even if the sheet feeding table 1 further rises after the release, it is possible to prevent deformation and destruction due to interference with other members.

  In the second embodiment, it is needless to say that the overrun prevention means may be provided only on the upper limit side.

(Third embodiment)
A sheet feeding device 92 to which a movable member overrun prevention device according to a third embodiment of the present invention is applied will be described. The sheet feeding device 92 according to the third embodiment is different from the sheet feeding device 90 according to the first embodiment in the overrun prevention device at the upper limit.

  FIGS. 15 to 18 show the upper-running prevention means on the upper limit side of the paper feeding device 92 according to the third embodiment. The drive circuit is once cut at a position immediately before the paper feed platform 1 as a movable member reaches the upper limit position. FIG. 8 is a diagram illustrating an operation when a release operation is performed thereafter and an operation when the upper limit position is reached by moving upward after the release operation. Members having the same functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 15 is a diagram illustrating a state in which the sheet feeding table 1 in the sheet feeding device 92 is below the position immediately before the upper limit. As shown in FIG. 15, the paper feeding device 92 has no first cam 52 of the paper feeding device 90 to which the movable member overrun prevention device according to the first embodiment is applied, and a spacer 85 is provided instead. Yes.

  The spacer 85 is provided on the upper surface of the sheet feed table 1, and a third shaft housing portion 85 a formed in a circular arc shape is formed in a portion immediately below the shaft 9 on the upper surface of the spacer 85.

  FIG. 16 is a diagram illustrating a state in which the paper feed tray 1 in the paper feed device 92 has reached the position immediately before the upper limit. If the sheet feed table 1 continues to rise due to an abnormality of the optical sensor S 1, the sheet feed table 1 reaches a position immediately before the upper limit, and the shaft 9 comes into contact with and is accommodated in the third shaft accommodating portion 85 a of the spacer 85. Then, the suction head unit 2 supporting the shaft 9 is pushed up. Then, since the suction head unit 2 rotates upward with the shaft 10 as a fulcrum, the operating member 53 supported by the shaft 9 also rises and cuts the upper limit micro switch 54. Then, since the drive circuit 63 is disconnected, the sheet feed table 1 stops regardless of the presence or absence of a stop signal from the CPU 60, and prevents deformation and destruction of the members.

  Therefore, the engagement unit includes the first engagement portion in which the shaft 9 and the operation member 53 engage with the spacer 85 (movable member) that moves together with the sheet feed table 1 and the second engagement portion that cuts the micro switch 54. Function as.

  Next, the disconnection of the drive circuit 63 is released. In the releasing operation, the spacer 85 is removed, and the engaging portion (first engaging portion) between the spacer 85 and the shaft 9 is released to lower the operating member 53 together with the shaft 9, and the operating member 53 and the lever This is performed by releasing the engagement (second engagement portion) with 54a. FIG. 17 is a view showing a state where the spacer 85 is removed. Since the spacer 85 itself that pushed up the shaft 9 is removed, the shaft 9 descends and comes into contact with the lower end of the elongated hole 50a and stops.

  Therefore, the operating member 53 is also lowered and separated from the lever 54a of the upper limit micro switch 54, and the cutting of the upper limit micro switch 54 is released. Then, the drive circuit 63 is connected again, and the paper feed table 1 can be moved up and down by a signal from the CPU 65. Can be lowered, facilitating inspection, repair and maintenance.

  FIG. 18 is a diagram illustrating a state in which the paper feed table 1 is re-raised and reaches the upper limit position after the spacer 85 is removed and the cutting of the upper limit micro switch 54 is released. When the sheet feed table 1 is further raised, the upper surface of the sheet feed table 1 is brought into contact with the suction head unit 2 and pushed up. Then, the operating member 53 is raised again and the upper limit micro switch 54 is disconnected. That is, since the drive circuit 63 is disconnected, the paper feed tray 1 stops regardless of the presence or absence of a stop signal from the CPU 65. Therefore, even if the sheet feeding table 1 further rises after the release, it is possible to prevent deformation and destruction due to interference with other members.

  It should be noted that marks such as lines and protrusions may be provided on the paper feed table 1 so that it is easy to place the spacer 85 at a predetermined position. Further, when the paper feed tray 1 is formed of a magnetic material, the spacer 85 can be stabilized by applying a magnet to the lower surface of the spacer 85 so as to be magnetized on the upper surface of the paper feed tray 1. . Also in the third embodiment, it is needless to say that the overrun prevention means may be provided only on the upper limit side.

2 Suction head unit, 9 axis, 15 level sensor, 52 1st cam, 53 actuating member, 54 upper limit micro switch, 55 2nd cam, 56 axis, 57 actuating member, 62 lower limit micro switch, 63 drive circuit, 90 paper feed Device, 91 paper feed device, 92 paper feed device, S1 optical sensor, S2 paper feed stand sensor

Claims (9)

A movable member movable between a first position and a second position by a drive source;
It is provided in at least one of the first position and the second position, and the movable member tries to move out of the range between the first position and the second position beyond the first position or the second position. In the overrun prevention device for the movable member having overrun prevention means for cutting the drive circuit for driving the movable member and stopping the movable member,
When the movable member arrives at a position immediately before reaching the first position or the second position, the overrun prevention means cuts the drive circuit to stop the movable member and cancels the disconnection of the drive circuit. After the release operation, if the movable member still moves in the same direction as before the drive circuit is cut and reaches the first position or the second position, the drive circuit is cut again to stop the movable member. A movable member overrun prevention device characterized by the above. The overrun prevention means includes an engagement unit having a first engagement portion that engages with the movable member, and a second engagement portion that engages with a switch that disconnects the drive circuit. When the position immediately before reaching the first position or the second position is reached, the movable member and the first engaging portion are engaged to move the engaging unit in one direction, so that the second engaging portion is Which activates the switch,
The release operation is an operation of moving the engagement unit in the other direction by changing the engagement state of the first engagement portion and releasing the engagement of the second engagement portion. The overrun prevention device for a movable member according to 1.   A cover member that covers a predetermined range including the switch and the second engagement portion so that a user's hand does not touch the first engagement portion; and the first engagement portion is outside the range covered with the cover member. The overrun prevention device for a movable member according to claim 2.   4. The overrun prevention device for a movable member according to claim 2, wherein the engagement unit is urged in a direction in which the first engagement portion faces the movable member. 5. The first engagement portion is a cam surface of a cam supported by a cam shaft provided in the engagement unit,
When the movable member arrives at a position immediately before reaching the first position or the second position, the movable member engages with the large-diameter portion of the cam and moves the engagement unit in one direction, thereby causing the second engagement. Engaging the switch with the switch to disconnect the drive circuit,
In the release operation, the engagement unit is moved in the other direction by rotating the cam so that the engagement position with the movable member is the small diameter portion of the cam, and the engagement of the second engagement portion with the switch is released. The overrun prevention device for a movable member according to any one of claims 2 to 4, wherein the device is an operation.   6. The engaging portion of the movable member with the cam is formed in a flat surface, and the small diameter portion of the cam is formed as a D-cut portion obtained by linearly cutting a part of a disk. The overrun prevention apparatus of the movable member of description. The movable member is movable in the vertical direction,
The first position and the second position are an upper limit position and a lower limit position, respectively, at which the movable member moves,
The overrun prevention means cuts the drive circuit of the movable member when the movable member is going to rise above the upper limit position,
7. The movable member overrun prevention device according to claim 5 or 6, wherein the cam shaft is provided horizontally. When the movable member arrives at a position immediately before reaching the first position or the second position, the movable member and the engagement unit engage and engage with each other with a spacer provided on either one of them. By moving the unit in one direction, the drive circuit is disconnected by engaging the second engagement portion with the switch,
In the release operation, the engagement unit is moved in the other direction by changing the engagement portion with the movable member or the engagement unit by sliding the spacer, and the engagement of the second engagement portion with the switch is released. The overrun prevention device for a movable member according to any one of claims 2 to 4, wherein the device is an operation. The overrun prevention means includes an engagement unit having a first engagement portion that engages with the movable member, and a second engagement portion that engages with a switch that disconnects the drive circuit,
When the movable member arrives at a position immediately before reaching the first position or the second position, the movable member and the engagement unit engage and engage with each other with a spacer provided on either one of them. By moving the unit in one direction, the drive circuit is disconnected by engaging the second engagement portion with the switch,
2. The release operation according to claim 1, wherein the release operation is an operation of releasing the engagement by moving the engagement unit in the other direction by removing the spacer and releasing the engagement. Overrun prevention device for movable members.

Images