Patent Publication Number: US-2006016669-A1

Title: Belt conveyor

Description:
BACKGROUND ART  
      1. Field of the Invention  
      The present invention relates to an energy-saving belt conveyor of wind-up type or a spring driven belt conveyor which can drive a conveyor belt by a spiral spring that is manually wound up only when needed or to an energy-saving belt conveyor which can drive a conveyor belt by manually releasing a stored energy in an elastic energy storage mechanism so as to wind up a wire of the elastic energy storage mechanism only when needed.  
      2. Description of the Related Art  
      A conventional belt conveyor generally has a continuous or endless conveyor belt. The conveyor belt is driven by a driving roller that is rotated by an electric motor or an air-driven motor so as to convey workpieces put on an upper surface of the conveyor belt.  
      For example, Japanese Patent No. 3058637 shows an invention of a belt conveyor. The belt conveyor is designed to reduce damage to a conveyor belt. The belt conveyor drives a conveyor belt by a driving roller with a built-in motor or by a driving roller connected to a motor having a reducer or the like.  
      However, all conventional belt conveyors including the belt conveyor as shown in Patent No. 3058637 are driven by the electric motor or the air-driven motor or the like. Therefore the conventional belt conveyors need electric power after all. Especially, it&#39;s often the case that a belt conveyor is continuously driven all day or 24 hours in a large factory. Consequently, the belt conveyor is sometimes driven alone without conveying any workpieces. As a result, there is huge waste of electrical energy. Moreover, a control system becomes too complex in a drive system using the conventional electric motor, the air-driven motor or the like to finely control the belt conveyor. Then, it was hard to move the belt conveyor by a desired distance, to convey workpieces on the belt conveyor to a desired position, to inch the conveyor belt, for example.  
     BRIEF SUMMARY OF THE INVENTION  
      An object of the present invention is to provide a spring driven belt conveyor that can drive a conveyor belt by a spiral spring by manually winding up the spring only when needed, thereby saving energy without using any electrical power and enables a fine control with ease.  
      Another object of the present invention is to provide a belt conveyor that can drive a conveyor belt by manually storing an energy in an expansion-contraction energy storing mechanism or an elastic energy storage mechanism and releasing the energy only when needed, thereby saving energy without using much or any electrical power and enables a fine control with ease.  
      A first aspect of an inventive spring driven belt conveyor comprises: a pair of frames separated away and opposed to each other; a drive shaft axially supported on one of the pair of the frames; a driven shaft axially supported on another of the pair of the frames; a drive roller attached to the drive shaft so as to rotate integrally with the drive shaft; a driven roller attached to the driven shaft so as to rotate integrally with the driven shaft; an endless conveyor belt stretched between the drive roller and the driven roller so as to run; a support, for supporting the conveyor belt, having opposite ends fixed on the pair of the frames between the drive roller and the driven roller; a spiral spring to which the drive shaft of the drive roller is connected so as to rotate; an input shaft axially supported on one of the pair of the frames so as to be separated away from the drive shaft; a rotating speed increasing mechanism provided between the input shaft and the drive shaft of the drive roller so as to transmit rotation of the input shaft to the drive shaft while increasing a rotation speed thereof and an input member attached to the input shaft.  
      The spiral spring may be disposed at an inside or an outside of the pair of the frames. In case the spiral spring is disposed at the outside of the pair of the frames, its repair is easy. However, since a protruded portion is generated, so that a position of the spiral spring should be selected and determined depending on a installed condition. Moreover, the spiral spring may be attached directly on the drive shaft or disposed on another gear shaft that gives a rotating force directly to the conveyor belt. Still, if it is directly connected, an energy loss can be lessened.  
      A spring driven belt conveyor may further comprises a one-way clutch through which the drive roller is attached to the drive shaft so that the drive roller is not rotated when the drive shaft is rotated in a direction to wind up the spiral spring, while the drive roller being rotated when the drive shaft is rotated in a direction to release the spiral spring.  
      In a spring driven belt, the rotating speed increasing mechanism may be composed of a combination of a plurality of gears including a gear fixed on the input shaft and a gear fixed on the drive shaft and rotary shaft provided respectively for the gears; and the gear fixed on the input shaft may have a toothless portion so that the gear fixed on the input shaft is disengaged from the gear meshing with the gear fixed on the input shaft at a position where the spiral spring is sufficiently wound up by operation of the input member.  
      In a spring driven belt conveyor, the rotating speed increasing mechanism may further include a one-way clutch through which one or more of the gears other than the gear fixed on the input shaft and the gear fixed on the drive shaft among the plurality of the gears is attached to the rotary shaft so that the same gear is integrally rotated when the rotary shaft of the same gear is rotated in a direction to wind up the spiral spring, while the same gear stops transmitting a rotating force when the drive shaft is rotated in a direction to release the spiral spring.  
      A spring driven belt conveyor may further comprise a weight attached inside the drive roller over an entire circumference of the drive roller so as to increase inertia of he drive roller.  
      A spring driven belt conveyor may further comprise a plurality of supporting legs attached to opposite sides of the support so as to hold the conveyor belt at a required height.  
      In a spring driven belt conveyor, the input member may have an input lever having one end fixed on the input shaft.  
      In the invention according to the first aspect or its modification, the rotating speed increasing mechanism is provided between the drive shaft to which the drive roller is attached for driving the conveyor belt and the input shaft on which the one end of the input lever is fixed. Therefore, if an operator holds the other end of the input lever and rotates the input lever in a given direction, the rotation of the input shaft is multiplied and transmitted to the drive shaft. Then, the spiral spring attached to the drive shaft is wound up. If the operator releases his or her hand at this time, the spiral spring is released and the drive shaft is rotated by an elastic force stored therein. Then, the drive roller is integrally rotated so as to drive the conveyor belt. A running distance of the conveyor belt can be adjusted as desired if a relation between an rotating angle of the input lever and a rotating number of the drive shaft is found out in advance.  
      Thus, it is possible to drive the conveyor belt by a necessary distance when needed without using an electric power. Moreover, if the input lever is rotated by a desired angle within a range of a wind-up limit of the spiral spring and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, the spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, thereby saving energy without using any electrical power and enables a fine control with ease.  
      When the input lever is rotated in a given direction by a given angle so as to wind up the spiral spring, the drive roller is not rotated. Therefore, the conveyor belt is not driven in a reverse direction. Moreover, it is possible to rotate the input lever with a little force without an extra force so as to wind up the spiral spring.  
      When the operator releases his or her hand from the input lever so as to rotate the drive shaft in a direction to release the spiral spring, the one-way clutch is engaged so that the drive roller is rotated integrally with the drive shaft. Consequently, the conveyor belt runs in a given direction. If the input lever is rotated by a desired angle within a range of a wind-up limit of the spiral spring and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, as well as being able to drive the conveyor belt with a little force so as to drive the conveyor belt, thereby saving energy without using any electrical power and enables a fine control with ease.  
      When the spiral spring is wound up sufficiently, the gear engaged with the gear fixed on the input shaft becomes in such a state as to run idle. Therefore, the spiral spring is released and the drive roller is rotated so as to drive the conveyor belt.  
      Thereby, the rotating force is not transmitted to the gear fixed on the input shaft and to the input shaft among the gears constituting the rotating speed increasing mechanism and the rotary shafts. Then, the input lever does not return to its original position. Consequently, the elastic force stored in the spiral spring is not used for rotating the input lever to the original position. Thus, the elastic force is effectively used without being wasted for unnecessary force. Moreover, it is possible to avoid such a danger as the input lever hits an operator when it is rotated to the original position. Furthermore, it is possible to surely avoid a case in which the input lever is rotated over the given angle thereby to wind up the spiral spring too much and damage it. If the input lever is rotated by a desired angle within such a range as the gear does not run idle and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, while preventing the spiral spring from being wound up too much and damaged, and can drive the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy without using any electrical power and enables a fine control with ease.  
      When the input lever is rotated to wind up the spiral spring, the rotating speed increasing mechanism transmits the rotating force while increasing the rotating speed. When the spiral spring is released and the drive roller is rotated so as to drive the conveyor belt, one of the rotary shaft and the gear runs idle so as not to transmit the rotating force to the input shaft and the input lever. Therefore, the elastic force stored in the spiral spring is not used more than is necessary for rotating all the plural gears constituting the rotating speed increasing mechanism and the input shaft and the input lever. Consequently, the elastic force is all used for rotating the drive roller after rotating the drive shaft and the gears near it. As a result, the conveyor belt can be driven efficiently.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, then driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy very much without using any electrical power and enabling a fine control with ease.  
      When the spiral spring is released to rotate the drive roller, the drive roller rotates by the inertia force several times more than a rotating number by a releasing of the spiral spring. Consequently, the conveyor belt can be driven at a longer distanced.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, then driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy very much without using any electrical power and enabling a fine control with ease.  
      The conveyor belt can be held at the required height to a certain height by making the pair of the frames high. However, it has a limit. Particularly, a material of the frame is wasted at the frame side on which the driven roller and the driven shaft are only attached. Then, the conveyor belt can be supported at the required height by attaching the supporting legs of he required height at the both sides of the support that is held between the pair of the frames for holding the conveyor belt.  
      The conveyor belt is not always supported substantially horizontally. The conveyor belt is supported slant as desired, that is, with a driven roller side higher or a driven roller side lower. Moreover, in case the support is wider than the conveyor belt and the opposite side surfaces are protruded from the conveyor belt, the plural supporting legs can be attached directly to the opposite side surfaces of the support. However, if the support is narrower than the conveyor belt and the opposite side surfaces of the support are retracted from the conveyor belt, interconnecting members need to be attached to the opposite side surfaces of the support so as to be protruded from the conveyor belt by a number of the supporting legs. Then, the supporting legs are attached to the interconnecting members.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, while supporting the conveyor belt at the required height, then driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy very much without using any electrical power.  
      In a spring driven belt conveyor, the input member may have a rotary handle disc attached to one end of the input shaft.  
      If the input shaft is rotated only about one half, the drive shaft is rotated several times so as to wind up the spiral spring at a burst only by the rotating speed increasing mechanism provided between the input shaft and the drive shaft. In contrast, a force for rotating the input shaft is several times larger than a force necessary for directly rotating the drive shaft.  
      Then, the input lever having a certain length is fixed on the input shaft. Thereby, the input shaft can be rotated easily by a principle of leverage. Instead, if the rotary handle disc is used, the rotary handle disc has a small diameter, so that a larger force is necessary to rotate the input shaft. Still, it saves a space. Moreover, in a structure in which the rotating force returns to the input shaft when the conveyor belt runs, it is safer for the operator to rotate the small diameter rotary handle disc than to rotate the long input lever to the original position.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, then more safely driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy very much without using any electrical power.  
      A spring driven belt conveyor may further comprise a clutch mechanism provided between the input shaft and the rotary handle disc.  
      After the rotary handle disc is rotated in a fixed direction by a fixed angle so as to wind up the spiral spring via the rotating speed increasing mechanism, it is possible to release connection of the input shaft and the rotary handle disc via the clutch mechanism. Then, the spiral spring is released to rotate the drive roller via the input shaft and the rotating speed increasing mechanism, thereby driving the conveyor belt. At this time, the rotary handle disc is not rotated, so that it is safer than a type in which the rotating force returns to the input shaft when the conveyor belt is driven.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, then more safely driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy very much without using any electrical power.  
      In a spring driven belt conveyor, the input member may have a step pedal attached to the input shaft so as to transmit a rotating force to the input shaft.  
      The input shaft can be rotated in a given direction by a given angle, thereby winding up the spiral spring so as to make the conveyor belt run. Moreover, it is easy to inch the conveyor belt by returning a foot pressing the step pedal little by little. Furthermore, the operator is free of his or her both hands, so that he or she can perform another work at the same time while driving the spring driven belt conveyor.  
      Consequently, a spring driven belt conveyor can drive the conveyor belt by the spiral spring by manually winding up the spring only when needed, then driving the conveyor belt effectively using the elastic force stored in the spiral spring, thereby saving energy without using any electrical power and enables a fine control with ease.  
      In a spring driven belt conveyor, the input member may further have a step pedal attached to a leading end of the input lever so as to transmit a rotating force to the input shaft.  
      A second aspect of an inventive belt conveyor comprises: a pair of frames separated away and opposed to each other; a drive shaft axially supported on the pair of the frames; a driven shaft axially supported on the pair of the frames; a drive roller attached to the drive shaft so as to rotate integrally with the drive shaft; a driven roller attached to the driven shaft so as to rotate integrally with the driven shaft; an endless conveyor belt stretched between the drive roller and the driven roller so as to run; a support limiting a downward movement of the conveyor belt and supporting a rear surface of the conveyor belt between the drive roller and the driven roller;  
      an expansion-contraction energy storing mechanism being able to determining a stored state of an energy by an expansion-contraction state in a longitudinal direction; and a rotatable pulley changing an expansion-contraction state in a longitudinal direction by the energy stored in the expansion-contraction energy storing mechanism if a human energy is applied to the expansion-contraction energy storing mechanism so as to mechanically rotate the drive roller only in a specified direction.  
      A second aspect of an inventive belt conveyor comprises: a pair of frames separated away and opposed to each other; a drive shaft axially supported on the pair of the frames; a driven shaft axially supported on the pair of the frames; a drive roller attached to the drive shaft so as to rotate integrally with the drive shaft; a driven roller attached to the driven shaft so as to rotate integrally with the driven shaft; an endless conveyor belt stretched between the drive roller and the driven roller so as to run; a support limiting a downward movement of the conveyor belt and supporting a rear surface of the conveyor belt between the drive roller and the driven roller; an expansion-contraction energy storing mechanism being able to determining a stored state of an energy by an expansion-contraction state in a longitudinal direction; a first rotatable pulley adapted to slide when the energy stored in the expansion-contraction energy storing mechanism is discharged; a retainer provided on the pair of the frames near the drive shaft; a second pulley fixed integrally and rotatably on the drive shaft; a wire having one end fixed on the retainer and another end fixed on the second pulley, while being passed around the first pulley and then wound around the second pulley; an input shaft axially supported on the pair of the frames so as to be separated away from the drive shaft; a rotating speed increasing mechanism provided between the input shaft and the drive shaft so as to transmit rotation of the input shaft to the drive shaft while increasing a rotation speed thereof; and an input member attached to the input shaft.  
      In a belt conveyor, the expansion-contraction energy storing mechanism may have a guide having a flange fixed on the pair of the frames so as to be parallel to the conveyor belt, a long rod fitted into the flanged guide so as to slide in a direction parallel to the conveyor belt, a spring holder fixed on the long rod near the driven roller, and a coil spring attached between the spring holder and the flange of the guide so as to surround the long rod.  
      A belt conveyor may further comprise a one-way clutch through which the drive roller is attached to the drive shaft so that the drive roller is not rotated when the drive shaft is rotated to make the expansion-contraction energy storing mechanism store the energy, while the drive roller being rotated when the drive shaft is rotated to discharge the energy stored in the expansion-contraction energy storing mechanism.  
      In a belt conveyor according to claim  14 , the rotating speed increasing mechanism may be composed of a combination of a plurality of gears including a gear fixed on the input shaft and a gear fixed on the drive shaft and rotary shaft provided respectively for the gears; and the gear fixed on the input shaft may have a toothless portion so that the gear fixed on the input shaft is disengaged from the gear meshing with the gear fixed on the input shaft at a position where the coil spring is sufficiently compressed by operation of the input member.  
      In a belt conveyor, the gear meshing with the gear fixed on the input shaft may have all teeth of a part cut off corresponding to a locus drawn by a tooth edge of an end tooth next to the toothless portion of the gear fixed on the input shaft when the end tooth is again engaged with the gear.  
      In a belt conveyor, the rotating speed increasing mechanism may further include a one-way clutch through which one or more of the gears other than the gear fixed on the input shaft and the gear fixed on the drive shaft among the plurality of the gears is attached to the rotary shaft so that the same gear is integrally rotated when the rotary shaft of the same gear is rotated in a direction to compress the coil spring, while the same gear stops transmitting a rotating force when the drive shaft is rotated in a direction to release the coil spring.  
      A belt conveyor may further comprise a weight attached inside the drive roller over an entire circumference of the drive roller so as to increase inertia of he drive roller.  
      A spring driven belt conveyor may further comprise a plurality of supporting legs attached to the support and/or at least one of the pair of the frames so as to hold the conveyor belt at a required height.  
      In a belt conveyor, the input member may have an input lever having one end fixed on the input shaft.  
      In the invention according to the second or the third aspect or its modification, the expansion-contraction energy storing mechanism may be composed of one having the coil spring or a spring plate assembled in a slide mechanism, one having an elastic rubber assembled therein, one that supplies compressed air by an air pump into an air cylinder with a stopper provided in a retracted state, one that compresses and expands an air cylinder by the input lever, one that attach a pinion rod to the coil spring or an air cylinder so as to rotate by a direct mesh with the pulley, or the like.  
      If a human energy is applied to the expansion-contraction energy storing mechanism, its expansion-contraction change in the longitudinal varies by the energy stored in the expansion-contraction energy storing mechanism. Consequently, the driven roller is mechanically rotated only in a specified direction via rotation of the pulley. As a result, the conveyor belt held on the drive roller rns in a predetermined direction.  
      Consequently, a belt conveyor can drive the conveyor belt by manually storing an energy in an expansion-contraction energy storing mechanism or an elastic energy storage mechanism and releasing the energy only when needed, thereby saving energy without using much or any electrical power and enabling a fine control with ease.  
      The rotating speed increasing mechanism is provided between the drive shaft to which the drive roller is attached for driving the conveyor belt and the input shaft on which the one end of the input lever is fixed. Therefore, if an operator holds the other end of the input lever and rotates the input lever in a given direction, the rotation of the input shaft is multiplied and transmitted to the drive shaft. Then, the second pulley attached integrally to the drive shaft is rotated so as to wind up the wire. Thereby, the first pulley on which the wire is put is pulled to the second pulley side. In this state, an energy is stored in the expansion-contraction energy storing mechanism.  
      If a stopper or the like is manually released, the second pulley and the drive shaft are rotated integrally by the energy stored in the expansion-contraction energy storing mechanism. Then, the drive roller is integrally rotated so as to drive the conveyor belt. A running distance can be adjusted as desired by finding out a relation between the energy stored in the expansion-contraction energy storing mechanism and the rotating number of the drive shaft.  
      Consequently, a belt conveyor can drive the conveyor belt by manually storing an energy in an expansion-contraction energy storing mechanism or an elastic energy storage mechanism and releasing the energy only when needed, thereby saving energy without using much or any electrical power and enabling a fine control with ease.  
      The rotating speed increasing mechanism is provided between the drive shaft to which the drive roller is attached for driving the conveyor belt and the input shaft on which the one end of the input lever is fixed. Therefore, if an operator holds the other end of the input lever and rotates the input lever in a given direction, the rotation of the input shaft is multiplied and transmitted to the drive shaft. Then, the second pulley attached integrally to the drive shaft is rotated so as to wind up the wire. Thereby, the first pulley on which the wire is put is pulled to the second pulley side. Then, the long rod integrally slides and the spring holder comes near the flange of the guide so as to compress the coil spring. At this time, if the operator releases his or her hand, the coil spring acts repulsively and expands. Then, the drive shaft is rotated integrally with the second pulley by the elastic force stored in the coil spring. Thereby, the drive roller is integrally rotated so as to drive the conveyor belt. A running distance can be adjusted as desired by finding out a relation between the energy stored in the expansion-contraction energy storing mechanism and the rotating number of the drive shaft.  
      Thus, it is possible to drive the conveyor belt by a necessary distance when needed without using an electric power. Moreover, if the input lever is rotated by a desired angle within a range of a compressing limit of the coil spring and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, a belt conveyor can drive the conveyor belt by manually compressing the coil spring only when needed, thereby saving energy without using any electrical power with a resultant large energy saving and can assure a fine control with ease.  
      When the input lever is rotated in a given direction by a given angle so as to compress the coil spring, the drive roller is not rotated. Therefore, the conveyor belt is not driven in a reverse direction. Moreover, it is possible to rotate the input lever with a little force without an extra force so as to compress the coil spring.  
      When the operator releases his or her hand from the input lever so as to rotate the drive shaft in a direction to release the coil spring, the one-way clutch is engaged so that the drive roller is rotated integrally with the drive shaft. Consequently, the conveyor belt runs in a given direction. If the input lever is rotated by a desired angle within a range of a compressing limit of the coil spring and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, a belt conveyor can drive the conveyor belt by manually storing an energy in an expansion-contraction energy storing mechanism or an elastic energy storage mechanism and releasing the energy only when needed, thereby saving energy without using much or any electrical power and enables a fine control with ease.  
      When the coil spring is compressed sufficiently, the gear engaged with the gear fixed on the input shaft becomes in such a state as to run idle. Therefore, the coil spring is released and the drive roller is rotated so as to drive the conveyor belt.  
      Thereby, the rotating force is not transmitted to the gear fixed on the input shaft and to the input shaft among the gears constituting the rotating speed increasing mechanism and the rotary shafts. Then, the input lever does not return to its original position. Consequently, the elastic force stored in the coil spring is not used for rotating the input lever to the original position. Thus, the elastic force is effectively used without being wasted for unnecessary force. Moreover, it is possible to avoid such a danger as the input lever hits an operator when it is rotated to the original position. Furthermore, it is possible to surely avoid a case in which the input lever is rotated over the given angle thereby to compress the coil spring too much and damage it. If the input lever is rotated by a desired angle within such a range as the gear does not run idle and returned little by little, it is easy to feed the conveyor belt by a slight distance or inch the conveyor belt.  
      Consequently, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, while preventing the coil spring from being compressed too much and damaged, and can drive the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy without using any electrical power and enables a fine control with ease.  
      When the toothless portion of the gear fixed on the input shaft arrives at the meshing part with the engaging gear, the engaging gear runs idle and the coil spring is released so as to rotate the drive roller and drive the conveyor belt. In order to drive the conveyor belt again, a toothed portion of the gear fixed on the input shaft is again meshed with the engaging gear and the input lever is rotated to its original position. Then, the input lever needs to be rotated from that position so as to compress the coil spring again.  
      However, the end tooth next to the toothless portion of the gear fixed on the input shaft is not always meshed well with the teeth of the engaging gear. In some cases, it is possible that top parts of the teeth of both the gears collide with each other and that the gears are not meshed. Then, all the teeth of the engaging gear are cut off at the part corresponding to the locus drawn by the tooth edge of the rotating end tooth so that the end tooth is meshed with the tooth of the engaging gear 100% successfully. Thereby, even if the top parts of the teeth of both the gears come to such a position as to collide with each other, the end tooth moves past the teeth without collision so as to contact with a non-cutoff side of a next tooth, since the tooth edge of the engaging gear is cut off. Thus, both the gear are meshed with each other well.  
      Consequently, the gear having the toothless portion and the gear engaging therewith can be always meshed without fail. Then, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, while preventing the coil spring from being compressed too much and damaged, and can drive the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy very much without using any electrical power.  
      When the input lever is rotated to compress the coil spring, the rotating speed increasing mechanism transmits the rotating force while increasing the rotating speed. When the coil spring is released and the drive roller is rotated so as to drive the conveyor belt, one of the rotary shaft and the gear runs idle so as not to transmit the rotating force to the input shaft and the input lever. Therefore, the elastic force stored in the coil spring is not used more than is necessary for rotating all the plural gears constituting the rotating speed increasing mechanism and the input shaft and the input lever. Consequently, the elastic force is all used for rotating the drive roller after rotating the drive shaft and the gears near it. As a result, the conveyor belt can be driven efficiently.  
      It is possible to repeat inching and finely adjusting a position of a workpiece on the conveyor belt by repeating an operation to rotate the input lever a little and return it.  
      Consequently, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, then driving the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy very much without using any electrical power and enabling a fine control with ease.  
      When the energy stored in the expansion-contraction energy storing mechanism is released to rotate the drive roller, the drive roller rotates by the inertia force several times more than a rotating number by the stored energy. Consequently, the conveyor belt can be driven at a longer distanced.  
      Consequently, a belt conveyor can drive the conveyor belt by manually storing an energy in an expansion-contraction energy storing mechanism or an elastic energy storage mechanism and releasing the energy only when needed, thereby saving energy very much without using much or any electrical power and enabling a fine control with ease.  
      The conveyor belt can be held at the required height to a certain height by making the pair of the frames high. However, it has a limit. Particularly, a material of the frame is wasted at the frame side on which the driven roller and the driven shaft are only attached. Then, the conveyor belt can be supported at the required height by attaching the supporting legs of he required height at the both sides of the support that is held between the pair of the frames for holding the conveyor belt.  
      The conveyor belt is not always supported substantially horizontally. The conveyor belt is supported slant as desired, that is, with a driven roller side higher or a driven roller side lower. Moreover, in case the support is wider than the conveyor belt and the opposite side surfaces are protruded from the conveyor belt, the plural supporting legs can be attached directly to the opposite side surfaces of the support. However, if the support is narrower than the conveyor belt and the opposite side surfaces of the support are retracted from the conveyor belt, interconnecting members need to be attached to the opposite side surfaces of the support so as to be protruded from the conveyor belt by a number of the supporting legs. Then, the supporting legs are attached to the interconnecting members.  
      Consequently, a belt conveyor can drive the conveyor belt by manually releasing the energy stored in the expansion-contraction energy storing mechanism only when needed, while supporting the conveyor belt at the required height, thereby saving energy very much without using any electrical power.  
      In a belt conveyor, the input member may have a rotary handle disc attached to one end of the input shaft.  
      If the input shaft is rotated only about one half, the drive shaft is rotated several times so as to compress the coil spring or the spring plate at a burst only by the rotating speed increasing mechanism provided between the input shaft and the drive shaft. In contrast, a force for rotating the input shaft is several times larger than a force necessary for directly rotating the drive shaft.  
      Then, the input lever having a certain length is fixed on the input shaft. Thereby, the input shaft can be rotated easily by a principle of leverage. Instead, if the rotary handle disc is used, the rotary handle disc has a small diameter, so that a larger force is necessary to rotate the input shaft. Still, it saves a space. Moreover, in a structure in which the rotating force returns to the input shaft when the conveyor belt runs, it is safer for the operator to rotate the small diameter rotary handle disc than to rotate the long input lever to the original position.  
      Consequently, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, then more safely driving the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy very much without using any electrical power.  
      A belt conveyor may further comprise a clutch mechanism provided between the input shaft and the rotary handle disc.  
      After the rotary handle disc is rotated in a fixed direction by a fixed angle so as to compress the coil spring via the rotating speed increasing mechanism, it is possible to release connection of the input shaft and the rotary handle disc via the clutch mechanism. Then, the coil spring is released to rotate the drive roller via the input shaft and the rotating speed increasing mechanism, thereby driving the conveyor belt. At this time, the rotary handle disc is not rotated, so that it is safer than a type in which the rotating force returns to the input shaft when the conveyor belt is driven.  
      Consequently, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, then more safely driving the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy very much without using any electrical power.  
      In a belt conveyor, the input member may have a step pedal attached to the input shaft so as to transmit a rotating force to the input shaft.  
      In a belt conveyor, the input member may further have a step pedal attached to a leading end of the input lever so as to transmit a rotating force to the input shaft.  
      The input shaft can be rotated in a given direction by a given angle, thereby compressing the coil spring so as to make the conveyor belt run. Moreover, it is easy to inch the conveyor belt by returning a foot pressing the step pedal little by little. Furthermore, the operator is free of his or her both hands, so that he or she can perform another work at the same time while driving the spring driven belt conveyor.  
      Consequently, a belt conveyor can drive the conveyor belt by the coil spring by manually compressing the coil spring only when needed, then more safely driving the conveyor belt effectively using the elastic force stored in the coil spring, thereby saving energy very much without using any electrical power.  
      Further objects and advantages of the invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the invention are clearly shown. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side elevation view showing an overall structure of a spring driven belt conveyor with a middle portion thereof cut away or omitted according to a first embodiment of the invention.  
       FIG. 2  is a top plan view showing an overall structure of the spring driven belt conveyor with a middle portion thereof cut away according to the first embodiment of the invention.  
       FIG. 3  is a vertical sectional view showing a structure of a drive section of the spring driven belt conveyor according to the first embodiment of the invention.  
       FIG. 4  is an enlarged left side elevation view showing the drive section of the spring driven belt conveyor according to the first embodiment of the invention.  
       FIG. 5  is a vertical sectional view showing a structure of a drive section of a spring driven belt conveyor according to a second embodiment of the invention.  
       FIG. 6  is an enlarged left side elevation view showing a drive section of a spring driven belt conveyor according to a third embodiment of the invention.  
       FIG. 7  is an enlarged left side elevation view showing a drive section of a spring driven belt conveyor according to a fourth embodiment of the invention.  
       FIG. 8  is a side elevation view showing an overall structure of a belt conveyor with a front side frame plate of a third frame dismounted and with a middle portion thereof cut away according to a fifth embodiment of the invention.  
       FIG. 9  is a top plan view showing an overall structure of the belt conveyor with a middle portion thereof cut away according to the fifth embodiment of the invention.  
       FIG. 10A  is a top plan view showing a structure of a drive section of the belt conveyor according to the fifth embodiment of the invention.  
       FIG. 10B  is a side elevation view showing the structure of the drive section of the belt conveyor according to the fifth embodiment of the invention.  
       FIG. 11  is a vertical sectional view showing a rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  
       FIG. 12  is a left side elevation view showing the rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  
       FIG. 13  is a partially enlarged left side elevation view showing the rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  
       FIG. 14  is a vertical sectional view showing a structure of a drive section of a belt conveyor according to a sixth embodiment of the invention.  
       FIG. 15  is an enlarged left side elevation view showing a drive section of a belt conveyor according to a seventh embodiment of the invention.  
       FIG. 16  is an enlarged left side elevation view showing a drive section of a belt conveyor according to an eighth embodiment of the invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Several embodiments of the invention are described hereunder referring to the attached drawings.  
     First Embodiment  
      A first embodiment of the invention is described hereafter referring to  FIG. 1  to  FIG. 4 .  
       FIG. 1  is a side elevation view showing an overall structure of a spring driven belt conveyor with a middle portion thereof cut away or omitted according to a first embodiment of the invention.  FIG. 2  is a top plan view showing an overall structure of the spring driven belt conveyor with a middle portion thereof cut away according to the first embodiment of the invention.  FIG. 3  is a vertical sectional view showing a structure of a drive section of the spring driven belt conveyor according to the first embodiment of the invention.  FIG. 4  is an enlarged left side elevation view showing the drive section of the spring driven belt conveyor according to the first embodiment of the invention.  
      Referring to  FIG. 1 , the first embodiment of the spring driven belt conveyor  1  is constructed with a basic framework. The basic framework is composed of a drive side frame  2 , a driven side frame  3 , an aluminum plate  10  and two pairs of support legs  11 . The drive side frame  2  is composed of two coated steel plates assembled with a not-shown aluminum rod held therebetween. The drive side frame  2  constitutes one of a pair of frames. The driven side frame  3  is composed of two coated steel plates that are spaced apart and opposed to the drive side frame  2 . The driven side frame  3  constitutes another of a pair of frames. The aluminum plate  10  as a support has its opposite ends fixed on the pair of the frames  2  and  3 . Each pair of the supporting legs  11  is attached on side surfaces of the aluminum plate  10  near the pair of the frames  2  and  3 , respectively. The far side supporting leg  11  is not shown in the  FIG. 1  due to overlap with the front side supporting leg  11 .  
      As shown in  FIG. 2 , a drive shaft  5   a  is horizontally and axially supported on the drive side frame  2 . A driving roller  5  is fixed to the drive side frame  2  so as to rotate integrally therewith. In the same way, a driven shaft  6   a  is horizontally and axially supported on the driven side frame  3 . A driven roller  6  is fixed to the driven side frame  3  so as to rotate integrally therewith. An endless conveyor belt  4  is held or stretched between the driving roller  5  and the driven roller  6 . An input shaft  7  is horizontally and axially supported on the drive side frame  2 . A rotating speed increasing mechanism described later is provided between the drive shaft  5   a  and the input shaft  7  in the drive side frame  2 . An input lever  8  is fixed on the input shaft  7  via a rotation ring  7   a.  A spiral spring  16  (not shown in  FIG. 1 ) is mounted on the drive shaft  5   a  at a far side of the drive side frame  2  as shown in  FIG. 2 . The spiral spring  16  is wound up by turning the input lever  8 .  
      The input lever  8  is in contact with a starting-point bar  9  in  FIG. 1 . The spiral spring  16  is in its most loose or unstrained state when the input lever  8  is located at such contact position. If a worker holds a grip  8   a  at a leading end of the input lever  8  and rotates the input lever  8  one hundred and fifty degrees in a right-handed a clockwise direction from such starting point as shown by an imaginary line in  FIG. 1 , the drive shaft  5   a  makes about three and a half rotations by an operation of the rotating speed increasing mechanism. Thereby, the spiral spring  16  is also wound up about three and a half rotations so as to store an elastic potential energy at a maximum.  
      The aluminum plate  10  as the support is wider than the conveyor belt  4 . Then, the side surfaces of the aluminum plate  10  are protruded respectively to the front side and the far side from the conveyor belt  4  as shown in  FIG. 2 . Thus, the supporting legs  11  can be directly attached to the side surfaces of the aluminum plate  10 . Still, a width of the aluminum plate  10  is too narrow to maintain stability of the supporting legs  11  which is vertically fixed to the aluminum plate  10 . Therefore, each of the supporting legs  11  has a pair of fixing plates  13  that is secured on to a pair of grooves  10   a  each formed along a center of the side surface of the aluminum plate  10  by fixing bolts  13 . Moreover, as shown in  FIG. 2 , each of the supporting legs  11  has a pair of leg pieces  12  provided at lower ends of the fixing plates  13  so as to be slanted and spread outward from a plane perpendicular to a page sheet of  FIG. 1 , namely, from the side surfaces of the aluminum plate  10  or side surfaces of the fixing plates  13 . Furthermore, lower ends  12   a  of the leg pieces  12  are respectively bent horizontally. In addition, bottom shafts  14  and rubber feet  15  are fixed on the lower ends  12   a  of the leg pieces  12  by nuts.  
      Thus, as shown in the top plan view of  FIG. 2 , the supporting legs  11  are spread right and left from the side surfaces of the aluminum plate  10  so as to be contacted with a ground surface. Thereby, the supporting legs  11  maintain enough stability to support the conveyor belt  4  at a given height. The aluminum plate  10  as the support is clamped and fixed to each of right and left sides of the drive side frame  2  by screwing four fixing bolts  10   b.  Thus, eight fixing bolts  10   b  are used. The aluminum plate  10  is also clamped and fixed to each of right and left sides of the driven side frame  3  by screwing two fixing bolts  10   c.  Thus, four fixing bolts  10   c  are used. As described before, the spiral spring  16  is housed in a spring box  16   a  while attached to the drive shaft  5   a  at the far side of the drive side frame  2 .  
      Next, the rotating speed increasing mechanism is described referring to  FIG. 3 . The spring box  16   a  is not shown in  FIG. 3 .  
      As shown in  FIG. 3 , between the two plated steel sheets of the drive side frame  2 , the drive shaft  5   a  is axially supported in a horizontal manner on the drive side frame  2  by two ball bearings  26 . The drive roller  5  is mounted on the drive shaft  5   a  via a one-way clutch  18  and the ball bearings  26  so as to rotate integrally with the drive shaft  5   a.  A weight  17  is attached along an entire circumference in the drive roller  5  so as to increase inertia. The conveyor belt  4  is wound around an outer circumference of the drive roller  5 . The spiral spring  16  is fitted on a part of the drive shaft  5   a  that is protruded from the drive side frame  2 . A center end of the spiral spring  16  is fixed on the drive shaft  5   a  by a spring fixing bolt  16   c.  An outer circumferential end of the spiral spring  16  is fixed on the drive side frame  2  by a spring fixing bolt  16   b.    
      A small diameter gear  20  is integrally fixed to an opposite side of the drive shaft  5   a.  This small gear  20  meshes with a large diameter gear  21 . The large gear  21  is fitted on a rotary shaft  21   a  through a one-way clutch  19 . The rotary shaft  21   a  is horizontally supported on the drive side frame  2  with its opposite ends axially held by the ball bearings  26 . A small diameter gear  22  is integrally fixed near a center of the rotary shaft  21   a.  The small gear  22  meshes with a large diameter gear  23 . The large gear  23  is integrally fixed to the input shaft  7 . The input shaft  7  is supported horizontally on the drive side frame  2  with its opposite ends held by the ball bearings  26 . The gear  23  has a toothless part  23   a  over about two fifths of its outer circumference. Retaining rings  24  are fitted respectively in required parts of the drive shaft  5   a,  the rotary shaft  21   a  and the input shaft  7  each supported by the ball bearings  26 .  
      In the first embodiment of the spring driven belt conveyor  1 , the gear  20  has thirty teeth, while the gear  21  has seventy-five teeth. The gear  22  has thirty teeth, while the gear  23  is to have one-hundred teeth if it has the teeth successively on the entire circumference. When the input lever  8  is rotated one hundred fifty degrees, a number of rotations of the drive shaft  5   a  is about 3.5 (three and a half) rotations as follows: (150 deg./360 deg.)*(100/30)×(75/30)≈3.5. Consequently the spiral spring  16  is wound up by about 3.5 rotations. In case a length of the spiral spring  16  is two meters when extended or stretched, the spiral spring  16  is stored with a maximum elastic potential energy.  
      A number of the teeth of the gear  23  determines a stored energy of the spiral spring  16  by its meshing operation in the first embodiment. Accordingly, the number naturally determines a moving distance of the conveyor belt  4 , i.e. a conveying distance. Moreover, the gear  22  and the gear  23  are disengaged rapidly, so that the energy stored in the spiral spring  16  can be output at a burst with a resultant high efficiency. In the first embodiment, if the input lever  8  is rotated 150 degrees from the original position shown in  FIG. 1 , the toothless part  23   a  of the gear  23  reaches a meshed position of the gear  22  and the gear  23 . Consequently, the gear  22  runs idle in a reverse direction so as to release the spiral spring  16 . Therefore, there is no problem that the spiral spring  16  is wound too much and damaged.  
      The one-way clutch  18  is fitted such that it does not transmit rotation to the drive roller  5  when the drive shaft  5   a  is rotated in a direction to wind up the spiral spring  16 , while permitting the drive roller  5  to be rotated integrally when the drive shaft  5   a  is rotated in a direction to release the spiral spring  16 . On the other hand, the one-way clutch  19  is fitted such that it transmits rotation to the gear  21  when the rotary shaft  21   a  is rotated in a direction to wind up the spiral spring  16 , while running idle without transmitting rotation to the rotary shaft  21   a  when the gear  21  is rotated in a direction to release the spiral spring  16 .  
      A running mechanism of the conveyor belt  4  in the spring driven belt conveyor  1  having such structure is described referring to  FIG. 3  and  FIG. 4 .  
      When an operator holds the grip  8   a  at the leading end of the input lever  8  shown in  FIG. 3  and turns the input lever  8  in a right direction or a clockwise direction when seen from the right side in  FIG. 3 , namely, to a far side in the sheet of  FIG. 3 , the input shaft  7  is rotated via the rotation ring  7   a.  Then, the gear  23  fixed on the input shaft  7  is rotated integrally. Accordingly, the gear  22  meshed with the gear  23  is integrally rotated with the rotary shaft  21   a  on which the gear  23  is fixed. In this case, the rotary shaft  21   a  is rotated in the direction to wind up the spiral spring  16 . Then, the one-way clutch  19  transmits the rotation to the gear  21 , so that the gear  12  is integrally rotated. Moreover, the gear  20  meshed with the gear  21  is integrally rotated with the drive shaft  5   a  on which the gear  20  is fixed. Then, the gear  20  begins winding up the spiral spring  16  that is attached to the other end. However, the one-way clutch  18  does not transmit the rotation to the drive roller  5 . Consequently, the conveyor belt  4  never moves in a reverse direction. As a result, it is possible to wind up the spiral spring  16  with a small force.  
      As described above, as the gear  23  is rotated in an arrow direction A as shown in  FIG. 4 , the gears  22  and  21  are rotated in an arrow direction B, while the gear  20  and the drive shaft  5   a  being rotated in an arrow direction C. Thus, the spiral spring  16  is wound up tightly little by little so as to store the elastic energy. Then, when a rotation angle in the arrow direction A reaches about 150 degrees, an end of the toothless part  23   a  of the gear  23  arrives a meshing part with the gear  22 . Thereby, the gear  23  becomes disengaged with the gear  22 . Consequently, the rotary shaft  21   a  and the drive shaft  5   a  are respectively rotated in a reverse direction to each of the arrow directions B and C by a releasing energy of the spiral spring  16 . As a result, the drive roller  5  is rotated in the left-hand direction or the counterclockwise direction so as to make the conveyor belt  4  run in the arrow direction D.  
      At this time, the one-way clutch  18  shown in  FIG. 3  transmits the rotation of the drive shaft  5   a  to the drive roller  5  so as to rotate the drive roller  5 . On the other hand, the one-way clutch  19  does not transmit the rotation of the gear  21  to the rotary shaft  21   a,  so that the gear  21  runs idle. Accordingly, a torque of the drive shaft  5   a  is only wasted for rotation of the gears  20  and  21  in addition to the rotation the drive roller  5 . Therefore, the elastic energy stored in the spiral spring  16  is used efficiently for driving the conveyor belt  4 . Moreover, since the weight  17  is fitted inside the drive roller  5 , the drive roller  5  is rotated several times more than the number of rotations by the releasing power of the spiral spring  16  by an inertia force of the weight  17 . Consequently, the conveyor belt  4  can be traveled at a longer distance.  
      As described above, in the spring driven belt conveyor  1  according to the first embodiment, the spiral spring  16  is manually wound up only when needed. Then, the conveyor belt  4  can be fed by winding up the spiral spring  16  with a little force without driving the conveyor belt  4  in the reverse direction. Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, there is no possibility that the spiral spring  16  is wound up too much and damaged.  
      If the input lever  8  shown in  FIG. 4  is rotated in the arrow direction A by a slight angle and returned in a reverse direction by a desired angle, the conveyor belt  4  can be moved little by little or inched. Still, even if the input lever  8  is returned in the reverse direction and stopped, the gear  21  runs idle by operation of the one-way clutch  19  provided on the gear  21 . Therefore, the conveyor belt  4  does not stop at such position but continues running until the spiral spring  16  is completely released and the inertia force of the drive roller  5  disappears.  
      Accordingly, the gear  21  is preferably fixed directly on the rotary shaft  21   a  without the one-way clutch  19  interposed therebetween as in the first embodiment. In such case, the conveyor belt  4  can be driven by a slight distance or inched more flexibly. Then, if the input lever  8  is rotated in the arrow direction A by a desired angle within an range of about 150 degrees and returned in the reverse direction and stopped thereat, the conveyor belt  4  stops at the same position. Thus, it is possible to convey a workpiece to a desired position by returning and stopping the input lever  8  while monitoring a position of the workpiece on the conveyor belt  4 .  
     Second Embodiment  
      A second embodiment of the invention is described referring to  FIG. 5 .  FIG. 5  is a vertical sectional view showing a structure of a drive section of a spring driven belt conveyor according to a second embodiment of the invention.  
      As shown in  FIG. 5 , a spring driven belt conveyor  31  according to the second embodiment has main components similar to those of the first embodiment of the spring driven belt conveyor  1 . Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description. The second embodiment is different from the first embodiment in the following points. First, a gear  28  having teeth over its entire circumference is fixed on the input shaft  7 , while the gear  23  having the toothless part  23   a  being fixed on the input shaft  7  in the first embodiment. Second, a rotary handle disc  35  is provided at the end of the input shaft  7  via a clutch mechanism  34 , while the input lever  8  is provided thereat in the first embodiment.  
      The clutch mechanism  34  is composed of a cylindrical gear  32  and a cylindrical gear  33 . The gear  34  is fixed at the end of the input shaft  7 . The rotary handle disc  35  is axially supported on the input shaft  7  so as to rotate and move forward and backward. The gear  33  is fixed on the rotary handle disc  35 . In a state shown in  FIG. 5 , the rotary handle disc  35  is in a backward position so that the clutch mechanism  34  is in a released position. If the rotary handle disc  35  is moved forward in an arrow direction from the above position, the cylindrical gear  32  and the cylindrical gear  33  are meshed with each other so that the clutch mechanism  34  is in an engaged state. Then, if an operator holds a handle  36  to turn the rotary handle disc  35  in a right-hand direction or a clockwise direction, the input shaft  7  is rotated. Thus, a torque is transmitted to the drive shaft  5   a  in the same way as the first embodiment, so that the spiral spring  16  is wound up.  
      In the second embodiment, the gear  28  fixed on the input shaft  7  has the teeth over the entire circumference. Therefore, when the input shaft  7  turns up to about 150 degrees that are a winding-up limit of the spiral spring  16 , the gear  22  never runs idle automatically or releases the spiral spring  16  in contrast with the first embodiment. Consequently, there is a need for providing a measure for preventing the spiral spring  16  from being wound up over the winding-up limit and being damaged. For such purpose, a rotation range may be clearly shown or specified at an outside of the drive side frame  2 , for example. Alternatively, a stopper may be disposed in relation to the handle  36 .  
      After the clutch mechanism  34  is engaged and the rotary handle disc  35  is turned to a desired angle within a rotation range by holding the handle  36 , the rotary handle disc  35  is held with both hands so as to move backward the rotary handle disc  35  and the cylindrical gear  33 . Thereby, the clutch mechanism  34  becomes in the released state. Then, the input shaft  7 , the gear  28 , the gear  22 , the rotary shaft  21   a,  the gear  21 , the gear  20  and the drive shaft  5   a  are rotated in a reverse direction by the elastic force stored in the spiral spring  16 . Accordingly, the drive roller  5  is rotated integrally with the drive shaft  5   a  by the operation of the one-way clutch  18 . Consequently, the conveyor belt  4  has its upper part fed out in a predetermined direction or a front direction in  FIG. 5  and its lower part fed into the drive roller  5 . Thus, the conveyor belt  4  runs.  
      At this time, the one-way clutch  19  does not transmit the rotation of the gear  21  to the rotary shaft  21   a,  so that the gear  21  runs idle. Accordingly, a torque of the drive shaft  5   a  is only wasted for rotation of the gears  20  and  21  in addition to the rotation of the drive roller  5 . Therefore, the elastic energy stored in the spiral spring  16  is used efficiently for driving the conveyor belt  4 . Moreover, since the weight  17  is fitted inside the drive roller  5 , the drive roller  5  is rotated several times more than the number of rotations by the releasing power of the spiral spring  16  by an inertia force of the weight  17 . Consequently, the conveyor belt  4  can be traveled at a longer distance.  
      As described above, in the spring driven belt conveyor  31  according to the second embodiment, the spiral spring  16  is manually wound up only when needed. Then, the conveyor belt  4  can be fed by winding up the spiral spring  16  with a little force without driving the conveyor belt  4  in the reverse direction. Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, the spring driven belt conveyor  31  can be installed at a small space since it uses the rotary handle disc  35  in place of the long input lever  8 .  
     Third Embodiment  
      A third embodiment of the invention is described referring to  FIG. 6 .  
       FIG. 6  is an enlarged left side elevation view showing a drive section of a spring driven belt conveyor according to a third embodiment of the invention. Most of components of a spring driven belt conveyor according to the third embodiment are similar to those of the first embodiment and the second embodiment. Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description.  
      As shown in  FIG. 6 , in the third embodiment of the spring driven belt conveyor  41 , the input shaft  7  is rotated not by hand power but by foot power in contrast with the first and the second embodiments. Specifically, while the input lever  8  is fixed on the input shaft  7  in the first and the second embodiment, a pinion gear  42  is fixed on the input shaft  7  so as to rotate integrally. A rack gear  43  meshing with the pinion gear  42  is fitted so as to move vertically. An elongate transmission shaft  44  is fixed vertically on a lower end of the rack gear  43  so as to reach a position near a floor surface. A lower end of the transmission shaft  44  is fitted in a rotatable manner on a step plate  45   a  of a step pedal  45 . The step pedal  45  is disposed on the floor surface.  
      A compression spring  46  is attached between the step plate  45   a  and a bottom plate  45   b  of the step pedal  45 . The compression spring  46  keeps its original state such that the rack gear  43 , the pinion gear  42  and the gear  23  return to their original positions shown in  FIG. 6 , when no force is applied to the step plate  45   a.  If an operator presses the step plate  45   a  by his or her foot from the above state, the rack gear  43  is vertically lowered together with the transmission shaft  44 . Then, the pinion  42  is rotated in an arrow direction A. Thus, the input shaft  7  and the gear  23  are rotated integrally so as to turn the rotary shaft  21   a  in an arrow direction B and the drive shaft  5   a  in an arrow direction C. Consequently, the spiral spring  16  fitted on the drive shaft  5   a  is wound up.  
      In the third embodiment, a gear ratio of the pinion gear  42  and the rack gear  43  is set such that the input shaft  7  is rotated about 150 degrees when the rack gear  43  is lowered about 10 cm. Then, if an operator presses the step plate  45   a  by about 10 cm, one end of the toothless part  23   a  of the gear  23  arrives at the meshing position of the gear  23  and the gear  22 . Thereby, the gear  22  runs idle so that the spiral spring  16  is released. Consequently, the drive shaft  5   a  and the rotary shaft  21   a  are rotated in reverse directions to arrow directions, respectively. Thus, the drive roller  5  is rotated integrally with the drive shaft  5   a  so as to feed out and drive the conveyor belt  4  in an arrow direction D. If the operator releases his or her pressing force after pushing the step plate  45   a  within the range of about 10 cm, the step plate  45   a  returns a little by a repulsive force of the compression spring  46 . Then, the rack gear  43  is raised a little. Thus, it is possible to rotate the input shaft  7 , the rotary shaft  21   a  and the drive shaft  5   a  in the reverse directions to the arrow directions, respectively, thereby inching the conveyor belt  4 .  
      As described above, in the spring driven belt conveyor  41  according to the third embodiment, the spiral spring  16  is wound up only when needed. Then, the conveyor belt can be driven more safely by use of the elastic force stored in the spiral spring  16 . Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, since the operator is free to use both hands, he or she can perform another work at the same time, while driving the spring driven belt conveyor  41 .  
     Fourth Embodiment  
      A fourth embodiment of the invention is described referring to  FIG. 7 .  FIG. 7  is an enlarged left side elevation view showing a drive section of a spring driven belt conveyor according to a fourth embodiment of the invention. Most of components of a spring driven belt conveyor according to the fourth embodiment are similar to those of the first to third embodiments. Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description.  
      As shown in  FIG. 7 , in the fourth embodiment of the spring driven belt conveyor  51 , the input shaft  7  is rotated not by hand power but by foot power, too. However, a step pedal  57  is mounted on a leading end of an input lever  56  in contrast with the third embodiment. It is almost impossible to rotate the input lever  56  by about 150 degrees only by foot press. Therefore, a small diameter gear  53  having thirty teeth is fixed on the input shaft  7 . A large diameter gear  54  having one hundred teeth is fixed on a second input shaft  55 . Then, the large gear  54  is meshed with the small gear  53 . The input lever  56  is secured on the second input shaft  55 . Thus, the belt conveyor is structured such that, if the input lever  56  is turned about 45 degrees, the input shaft  7  is rotated about 150 degrees. Accordingly, a drive frame  52  as one of a pair of frames becomes large according to increase of a size of a rotating speed increasing mechanism.  
      With the spring driven belt conveyor  51  having such structure, if the operator presses the step pedal  57  by his or her foot, the input lever  56  is turned in an arrow direction. Then, the second input shaft  55  and the gear  54  are rotated integrally so as to make the meshed gear  53  rotate in the arrow direction A. Thereby, the input shaft  7  and the gear  23  are integrally rotated so as to turn the rotary shaft  21   a  in an arrow direction B and the drive shaft  5   a  in an arrow direction C. Consequently, the spiral spring  16  fitted to the drive shaft  5   a  is wound up. If the operator turns the step pedal  57  by about 45 degrees, one end of the toothless part  23   a  of the gear  23  arrives at a meshing position of the gear  23  and the gear  22 . Then, the gear  22  runs idle. Therefore, the spiral spring  16  is released so that the drive shaft  5   a  and the rotary shaft  21   a  are rotated in the reverse directions to the arrow directions, respectively. Consequently, the drive roller  5  is rotated integrally with the drive shaft  5   a  so as to feed out and drive the conveyor belt  4  in an arrow direction D.  
      As described above, in the spring driven belt conveyor  51  according to the fourth embodiment, the spiral spring  16  is wound up only when needed. Then, the conveyor belt can be driven more safely by use of the elastic force stored in the spiral spring  16 . Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, since the operator is free to use both hands, he or she can perform another work at the same time, while driving the spring driven belt conveyor  51 .  
      The first embodiment is described on an example in which the gear  23  is made of a fiber reinforced plastic or FRP. However, the gear  23  may be made of a normal steep for gears. To the contrary, the other gears  20 ,  21  and  22  may be made of FRP. In the second embodiment, the gears  20 ,  21 ,  22  and  28  may be made of FRP. In these cases, there is an advantageous effect that the rotating speed increasing mechanism becomes light and a load applied to the supporting legs  11  lessens.  
      In practicing the invention of the first to the fourth embodiments, the spring driven belt conveyor is not limited to those of each of the above embodiments in the structure, shape, number, material, dimension, connecting relation or the like of the other components or parts.  
      In embodying the invention of the first to the fourth embodiments, the mechanism may be disposed as follows. Specifically, the spiral spring  16  is wound up within a range of the winding up limit, while the conveyor belt  4  being restrained from movement. Then, the restraint of the conveyor belt  4  is released by a predetermined button operation so as to make the energy of the spiral spring  16  discharged.  
      Since the inventive belt conveyor uses no electricity, the inventive belt conveyor according to the first to the fourth embodiments is applicable to a watery workplace, for example, a kitchen, a farm workplace under the scorching sun, or carrying in a water tank and carrying out of the water tank in which the conveyor is put in water. In the kitchen, the inventive belt conveyor requires no waterproof wiring for improving electric insulation of an isolation transformer or the like even in case of delivery and receipt between the kitchen and a service room. Consequently, the belt conveyor becomes inexpensive.  
      When the inventive belt conveyor according to the first to the fourth embodiment is not driven, it does not use energy at all. Therefore, the inventive belt conveyor has a energy saving effect in contrast with the conventional belt conveyor that is always operated continuously.  
      The inventive belt conveyor according to the first to the fourth embodiments is also applicable to transport between a mixing room and a delivery room of a pharmacy or the like, delivery and receipt between a clean room and an outside, sorting work and transport after sorting in a sorting or grading place of vegetables and fruits, and, as a matter of course, to delivery from labor-intensive workplace in an assembly plant to a main conveyor, assembly and transport of parts in a group unit or the like, transport in a box or case packaged unit or the like.  
     Fifth Embodiment  
      A fifth embodiment of the invention is described hereafter referring to  FIG. 8  to  FIG. 13 .  
       FIG. 8  is a side elevation view showing an overall structure of a belt conveyor with a front side frame plate of a third frame dismounted and with a middle portion thereof cut away according to a fifth embodiment of the invention.  FIG. 9  is a top plan view showing an overall structure of the belt conveyor with a middle portion thereof cut away according to the fifth embodiment of the invention.  FIG. 10A  is a top plan view showing a structure of a drive section of the belt conveyor according to the fifth embodiment of the invention.  FIG. 10B  is a side elevation view showing the structure of the drive section of the belt conveyor according to the fifth embodiment of the invention.  FIG. 11  is a vertical sectional view showing a rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  FIG. 12  is a left side elevation view showing the rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  FIG. 13  is a partially enlarged left side elevation view showing the rotating speed increasing transmission mechanism of the belt conveyor according to the fifth embodiment of the invention.  
      Referring to  FIG. 8 , the fifth embodiment of the belt conveyor  101  is constructed mainly with the following components. Specifically, a driven side frame  102  as a second frame is composed of a pair of frame plates assembled with a support (not shown) held therebetween. A drive side frame (not shown) as a first frame is placed opposite to and spaced apart from the driven side frame  102 , while sharing a middle frame plate with a third frame  103 . A drive shaft  105   a  is axially supported on the drive side frame. A drive roller  105  is attached to the drive shaft  105   a  so as to rotate integrally therewith. A driven shaft (not shown) is axially supported on the driven side frame  102 . A driven roller  106  is attached to the driven shaft so as to rotate integrally therewith. An endless drivable conveyor belt  104  is held and stretched between the drive roller  105  and the driven roller  106 .  
      As shown in  FIG. 9 , an aluminum plate  125  as a support has its opposite ends fixed on the pair of the drive side frame (not shown) and the driven side frame  102 . A panel  120  of a channel cross-section is protruded to opposite sides of the aluminum plate  125  so as to cover the opposite side surfaces of the conveyor belt  104 . The panel  120  is fastened on the aluminum plate  125  by screws entirely between the drive side frame (not shown) and the drive side frame  102 . One supporting leg  121  is fitted on a left end of a bottom surface of the channel section panel  120 , while two supporting legs  121  being fitted on a right end of the third frame  103 , though one of them is not show because it is overlapped. The supporting legs  121  serve to hold the conveyor belt  104  at a required height. Channel members  122  are fixed respective on lower ends of these three supporting legs  121  so as to extend in a direction perpendicular to a sheet plane of  FIG. 8  or a horizontal direction in  FIG. 9 , thereby keeping stability of the supporting legs  121 . Support bases  123  are secured on a front side and a far side of the channel member  122 , respectively.  
      A flanged guide  113  is fixed on the middle frame plate  103 B of the third frame  103  so as to extend in parallel to the conveyor belt  104 . A long rod  114  is fitted into the flanged guide  113  so as to slide in a parallel direction to the conveyor belt without jounce. A spring holder  115  is fixed on a left end of the long rod  114 . A coil spring  116  is mounted between a flange  113   a  of the flanged guide  113  and the spring holder  115  so as to surround the long rod  114 . A first pulley  107  is attached to a right end of the long rod  114  so as to rotate. One end of a strong and soft wire  108  is fixed on the middle frame plate  103 B of the third frame  103 . A second pulley  109  is fixed on the drive shaft  105   a,  which is protruded inside the third frame  103 , so as to rotate integrally therewith. The wire  108  is wound around the first pulley  107  and then wound around the second pulley  109 . The wire  108  has another end fixed on the second pulley  109 .  
      An input shaft  111  is axially and horizontally supported on a right end of the third frame  103  in the same manner as the drive shaft  105   a,  while being separated away from the input shaft  105   a.  An input lever  112  is fixed on the input shaft  111  so as to rotate integrally therewith. A rotating speed increasing mechanisms  110  is disposed between the input shaft  111  and the drive shaft  105   a  so as to increase and transmit a rotating speed of the input shaft  111  to the drive shaft  105   a.    
      The belt conveyor  101  according to the fifth embodiment is described more in detail referring to the plan view of  FIG. 9 . As shown in  FIG. 9 , an outside frame plate  103 A of the first frame is provided at a far side of the middle frame plate  103 B of the third frame  103 . The drive shaft  105  is supported axially and horizontally between the outside frame plate  103 A and the middle frame plate  103 B.  
      The drive roller  105  is attached to the drive shaft  105   a  so as to rotate integrally therewith. The first frame is composed of the outside frame plate  103 A and part of the middle frame plate  103 B. The second frame is provided away from and opposite to the first frame. An aluminum plate  125  is held or stretched between the first frame and the second frame  102 , while being fixed on the first frame and the second frame  102 , respectively.  
      The endless conveyor belt  104  is held in a stretched manner between the drive roller  105  and the driven roller  106 . As described later, if the input lever  112  is operated, the conveyor belt  104  moves at high speed in a white or outline arrow direction so as to carry products or the like. As describer before, the supporting legs  121  are attached to the left end of the bottom surface of the channel shaped panel  120  so as to support the conveyor belt  104  at a required height. Moreover, the channel shaped members  122  are fixed on the lower ends of the supporting legs  121 , while the support bases  123  are fixed on the opposite ends of the channel shaped members  122 , respectively. Two supporting legs having a similar structure are fixed on a right end of the bottom surface of the third frame  103 , though they are eliminated from illustration in  FIG. 9 .  
      A drive mechanism of the fifth embodiment of the belt conveyor  101  is described more in detail referring to  FIG. 10A  and  FIG. 10B . As shown in  FIG. 10A  and  FIG. 10B , a bracket  113   b  is formed integrally with the flange  113   a  of he flanged guide  113 . The bracket  113   b  is screwed on the middle frame plate  10 B by four screws. As shown in  FIG. 10A , an auxiliary roller  120   a  is axially supported between the outside frame plate  103 A and the middle frame plate  103 B so as to rotate. As shown in  FIG. 10B , the auxiliary roller  120   a  improves more a tension of the conveyor belt  104 . Then, the auxiliary roller  120   a  makes a lower side of the conveyor belt  104  generally parallel to an upper side of the conveyor belt  104  from the auxiliary roller  120   a  to the driven roller  106 , thereby improving an appearance.  
      The coil spring  116  is changed from a compressed state shown by a solid line to an extended state shown by an imaginary line. Accordingly, the long rod  114  slides at high speed from a position shown by a solid line to a position shown by an imaginary line. Then, a rubber stopper  126  is provided in order to absorb an impact shock given by the spring holder  115  colliding with a left end of the third frame  103  at that time. Moreover, a wire restrainer  109   a  is fixed near the second pulley  109  so as to prevent the wire  108  wound around the second pulley  109  from being undulated and disengaged from the second pulley  109  when the second pulley  109  is rotated at high speed at this time. The wire restrainer  109   a  has a deep groove cut at its end surface. The wire  108  passes through the groove. One end of the wire  108  is securely fixed on a wire stopper  108   a.  The wire  108  is wound around the first pulley  107  and then passed through the deep groove of the wire restrainer  109   a  and wound around the second pulley  109 . Thereafter, the other end of the wire  108  is securely fixed on the second pulley  109 .  
      A small diameter gear  130  is fixed at a far side of the second pulley  109  that is secured on the drive shaft  105   a  protruded inside the third frame  103 . The gear  130  rotates integrally with the drive shaft  105   a.  A large diameter gear  131  is meshed with the gear  130 . The gear  131  rotates with integrally with a rotary shaft  133  axially supported on the third frame  103 . A small diameter gear  132  is fixed on the rotary shaft  133  so as to rotate integrally therewith. A large diameter gear  134  is meshed with the gear  132 . The gear  134  has teeth only over about a half circumference. The gear  134  is fixed on the input shaft  111  so as to rotate integrally therewith. When the input shaft  111  rotates, the gear  134 , the gear  132 , the gear  133 , the gear  131  and the gear  130  increase a rotating speed so as to transmit the rotation to the drive shaft  105   a.  Accordingly, the gear  130 , the gear  131 , the gear  132 , the gear  133  and the gear  134  constitute the rotating speed increasing mechanism  110 .  
      The rotating speed increasing mechanism  110  is described more in detail referring to  FIG. 11 . As shown in  FIG. 11 , between the two plated steel sheets or the frame plates  103 A and  103 B constituting the first frame, the drive shaft  105   a  is axially supported in a horizontal manner on the two plated steel sheets or the frame plates  103 A and  103 B by two ball bearings  137 . The drive roller  105  is mounted the drive shaft  105   a  via a one-way clutch  135  and the ball bearings  137  so as to rotate integrally with the drive shaft  105   a.  A weight  140  is attached along an entire circumference in the drive roller  105  so as to increase inertia. The conveyor belt  104  is wound around an outer circumference of the drive roller  105 . The small diameter gear  130  is integrally fixed on a portion of the drive shaft  105   a  that is protruded from the middle frame plate  103 B. The second pulley  109  for winding up the wire  108  is secured on an outside of the protruded portion of the drive shaft  105   a.  The rotary shaft  133  has its opposite ends supported axially on the third frame  103  via the ball bearings  137 . The large diameter gear  131  meshing with the gear  130  is mounted on the rotary shaft  133  via a one-way clutch  136 .  
      The small diameter gear  132  is fixed integrally at an axial center side of the rotary shaft  133 . The input shaft  111  has its opposite ends supported axially and horizontally on the third frame  103  via the ball bearings  137 . The large diameter gear  134  meshing with the gear  132  is integrally fixed on the input shaft  111 . The gear  134  has a toothless portion  134   a  over about two fifth of its outer circumference. Retainer rings  138  are fitted in necessary parts of the drive shaft  105   a,  the rotary shaft  133  and the input shaft  111  each of which is supported by the ball bearings  137 .  
      A number of teeth of the gear  134  of the belt conveyor  101  according to the fifth embodiment determines an energy stored in the coil spring  116  by its meshing operation. A moving distance of the conveyor belt  104 , that is, a conveying distance is naturally determined in accordance with such number. Since the gear  132  and the gear  134  are disengaged rapidly, so that the energy stored in the coil spring  116  can be output at a burst with a resulting high efficiency. In the fifth embodiment, if the input lever  112  is rotated a predetermined angle from an original position shown by an imaginary line in  FIG. 8  and  FIG. 10B , the toothless part  134   a  of the gear  134  reaches a meshed position of the gear  132  and the gear  134 . Consequently, the gear  132  runs idle in a reverse direction so as to release the coil spring  116 . Therefore, there is no problem that the coil spring  116  is compressed too much and damaged.  
      The one-way clutch  135  is fitted such that it does not transmit rotation to the drive roller  105  when the drive shaft  105   a  is rotated in a direction to compress the coil spring  116 , while permitting the drive roller  105  to be rotated integrally when the drive shaft  105   a  is rotated in a direction to release the coil spring  116 . On the other hand, the one-way clutch  136  is fitted such that it transmits rotation to the gear  131  when the rotary shaft  133  is rotated in a direction to compress the coil spring  116 , while running idle without transmitting rotation to the rotary shaft  133  when the gear  131  is rotated in a direction to release the coil spring  116 .  
      A running mechanism of the conveyor belt  104  in the belt conveyor  101  having such structure is described referring to  FIG. 8  to  FIG. 12 . When an operator holds a grip  112   a  at the leading end of the input lever  112  shown in  FIG. 11  and turns the input lever  112  in a right direction or a clockwise direction in  FIG. 8 , namely, the input shaft  111  is rotated via the rotation ring  111   a  shown in  FIG. 11 . Then, the gear  134  fixed on the input shaft  111  is rotated integrally. Accordingly, the gear  132  meshed with the gear  134  is integrally rotated with the rotary shaft  133  on which the gear  132  is fixed. In this case, the rotary shaft  133  is rotated in the direction to compress the coil spring  116 . Then, the one-way clutch  136  transmits the rotation to the gear  131 , so that the gear  131  is integrally rotated.  
      Moreover, the gear  130  meshed with the gear  131  is integrally rotated with the drive shaft  105   a  on which the gear  130  is fixed. Then, the second pulley  109  fixed on the drive shaft  105   a  is rotated in a direction to wind up the wire  108 . Thereby, as shown in  FIG. 8 , the first pulley  107  at the original position shown by the imaginary line is pulled to the right side as the wire  108  is wound up. Consequently, the long rod  114  slides from the original position shown by the imaginary line to the position shown by the solid line, so that the coil spring  116  in a released state is compressed as shown by a solid line. At this time, the one-way clutch  135  shown in  FIG. 11  does not transmit rotation to the drive roller  105 , so that the conveyor belt  104  never runs in a reverse direction. As a result, it is possible to compress the coil spring  116  with a small force.  
      As described above, as the gear  134  is rotated in an arrow direction A as shown in  FIG. 12 , the gears  132  and  131  are rotated in an arrow direction B, while the gear  130  and the drive shaft  105   a  being rotated in an arrow direction C. Thus, the coil spring  116  is compressed strongly little by little so as to store the elastic energy. Then, when a rotation angle in the arrow direction A reaches a predetermined angle, an end of the toothless part  134   a  of the gear  134  arrives a meshing part with the gear  132 . Thereby, the gear  134  becomes disengaged with the gear  132 . Consequently, the rotary shaft  133  and the drive shaft  105   a  are respectively rotated in a reverse direction to each of the arrow directions B and C by an extending energy of the coil spring  116 . As a result, the drive roller  105  is rotated in the left-hand direction or the counterclockwise direction so as to make the conveyor belt  104  run in the arrow direction D.  
      At this time, the one-way clutch  135  shown in  FIG. 11  transmits the rotation of the drive shaft  105   a  to the drive roller  105  so as to rotate the drive roller  105 . On the other hand, the one-way clutch  136  does not transmit the rotation of the gear  131  to the rotary shaft  133 , so that the gear  131  runs idle. Accordingly, a torque of the drive shaft  105   a  is only wasted for rotation of the gears  130  and  131  in addition to the rotation the drive roller  105 . Therefore, the elastic energy stored in the coil spring  116  is used efficiently for driving the conveyor belt  104 . Moreover, since the weight  140  is fitted inside the drive roller  105 , the drive roller  105  is rotated several times more than the number of rotations by the releasing power of the coil spring  116  by an inertia force of the weight  140 . Consequently, the conveyor belt  104  can be traveled at a longer distance.  
      In order to drive the conveyor belt  104  in a next operation, the gear  134  fixed on the input shaft  111  is rotated in an arrow direction to make a toothed portion of the gear  134  meshed with the engaging gear  132  again as shown in  FIG. 13 . Then, the input lever  112  is rotated to the original position. Thereafter, the input lever  112  needs to be rotated more so as to compress the coil spring  116  again. However, an end tooth next to the toothless portion  134   a  of the gear  134  fixed on the input shaft  111  is not always meshed successfully again with a tooth of the meshing gear  132 . There arise some cases in which both top parts of the teeth of the gears  132  and  134  collide with each other and the gears  132  and  134  are not meshed well.  
      Then, in the fifth embodiment, as shown in  FIG. 13 , all the teeth of the meshing gear  132  are cut off over a part  132   a  corresponding to a locus drawn by a tooth edge of the end tooth of the gear  134 . Thus, the end tooth of the gear  134  is meshed with the tooth of the meshing gear  132  100% successfully. Thereby, even when both the gear  132  and  134  come to a position where the top parts of their teeth collide with each other, the end tooth of the gear  134  dodges the tooth of the gear  132  without colliding therewith, since the tooth edge  132   a  of the meshing gear  132  is cut off. Then, the end tooth of the gear  134  comes into contact with a non-cut side of a next tooth of the gear  132  so that both the gear  132  and  134  are meshed 100% successfully.  
      As described above, in the belt conveyor  101  according to the fifth embodiment, the coil spring  116  is manually compressed only when needed. Then, the conveyor belt  104  can be fed by compressing the coil spring  116  with a little force without driving the conveyor belt  104  in the reverse direction. Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, there is no possibility that the coil spring  116  is compressed too much and damaged.  
      If the input lever  112  shown in  FIG. 12  is rotated in the arrow direction A by a slight angle and returned in a reverse direction by a desired angle, the conveyor belt  104  can be moved little by little or inched. Still, even if the input lever  112  is returned in the reverse direction and stopped, the gear  21  runs idle by operation of the one-way clutch  136  provided on the gear  21 . Therefore, the conveyor belt  104  does not stop at such position but continues running until the coil spring  116  is completely released and the inertia force of the drive roller  105  disappears.  
     Sixth Embodiment  
      A sixth embodiment of the invention is described referring to  FIG. 14 .  FIG. 14  is a vertical sectional view showing a structure of a drive section of a belt conveyor according to a sixth embodiment of the invention. As shown in  FIG. 14 , a belt conveyor  141  according to the sixth embodiment has main components similar to those of the fifth embodiment of the belt conveyor  101 . Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description. The sixth embodiment is different from the fifth embodiment in the following points. First, a gear  147  having teeth over its entire circumference is fixed on the input shaft  111 , while the gear  134  having the toothless part  134   a  being fixed on the input shaft  111  in the fifth embodiment. Second, a rotary handle disc  145  is provided at the end of the input shaft  111  via a clutch mechanism  144 , while the input lever  112  is provided thereat in the fifth embodiment.  
      The clutch mechanism  144  is composed of a cylindrical gear  142  and a cylindrical gear  143 . The gear  144  is fixed at the end of the input shaft  111 . The rotary handle disc  145  is axially supported on the input shaft  111  so as to rotate and move forward and backward. The gear  143  is fixed on the rotary handle disc  145 . In a state shown in  FIG. 14 , the rotary handle disc  145  is in a backward position so that the clutch mechanism  144  is in a released position. If the rotary handle disc  145  is moved forward in an arrow direction from the above position, the cylindrical gear  142  and the cylindrical gear  143  are meshed with each other so that the clutch mechanism  144  is in an engaged state. Then, if an operator holds a handle  146  to turn the rotary handle disc  145  in a right-hand direction or a clockwise direction, the input shaft  111  is rotated. Thus, a torque is transmitted to the drive shaft  105   a  in the same way as the fifth embodiment, so that the coil spring  116  is compressed.  
      In the sixth embodiment, the gear  147  fixed on the input shaft  111  has the teeth over the entire circumference. Therefore, when the input shaft  111  turns up to a compressing limit of the coil spring  116 , the gear  132  never runs idle automatically or releases the coil spring  116  in contrast with the fifth embodiment. Consequently, there is a need for providing a measure for preventing the coil spring  116  from being compressed over the compressing limit and being damaged. For such purpose, a rotation range may be clearly shown or specified at the outside frame plate  103 C of the third frame  103 , for example. Alternatively, a stopper may be disposed in relation to the handle  146 .  
      After the clutch mechanism  144  is engaged and the rotary handle disc  145  is turned to a desired angle within a rotation range by holding the handle  146 , the rotary handle disc  145  is held with both hands so as to move backward the rotary handle disc  145  and the cylindrical gear  143 . Thereby, the clutch mechanism  144  becomes in the released state. Then, the input shaft  111 , the gear  147 , the gear  132 , the rotary shaft  133 , the gear  131 , the gear  130  and the drive shaft  105   a  are rotated in a reverse direction by the elastic force stored in the coil spring  116 . Accordingly, the drive roller  105  is rotated integrally with the drive shaft  105   a  by the operation of the one-way clutch  135 . Consequently, the conveyor belt  104  has its upper part fed out in a predetermined direction or a far side direction in  FIG. 14  and its lower part fed into the drive roller  105 . Thus, the conveyor belt  104  runs.  
      At this time, the one-way clutch  136  does not transmit the rotation of the gear  131  to the rotary shaft  133 , so that the gear  131  runs idle. Accordingly, a torque of the drive shaft  105   a  is only wasted for rotation of the gears  130  and  131  in addition to the rotation of the drive roller  105 . Therefore, the elastic energy stored in the coil spring  116  is used efficiently for driving the conveyor belt  104 . Moreover, since the weight  140  is fitted inside the drive roller  105 , the drive roller  105  is rotated several times more than the number of rotations by the releasing power of the coil spring  116  by an inertia force of the weight  140 . Consequently, the conveyor belt  104  can be traveled at a longer distance.  
      As described above, in the belt conveyor  141  according to the sixth embodiment, the coil spring  116  is manually compressed only when needed. Then, the conveyor belt  104  can be fed by compressing the spiral spring  116  with a little force without driving the conveyor belt  104  in the reverse direction. Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, the belt conveyor  141  can be installed at a small space since it uses the rotary handle disc  145  in place of the long input lever  112 .  
     Seventh Embodiment  
      A seventh embodiment of the invention is described referring to  FIG. 15 .  FIG. 15  is an enlarged left side elevation view showing a drive section of a belt conveyor according to a seventh embodiment of the invention. Most of components of a belt conveyor according to the seventh embodiment are similar to those of the fifth embodiment and the sixth embodiment. Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description.  
      As shown in  FIG. 15 , in the seventh embodiment of the belt conveyor  151 , the input shaft  111  is rotated not by hand power but by foot power in contrast with the fifth and the sixth embodiments. Specifically, while the input lever  112  is fixed on the input shaft  111  in the fifth and the sixth embodiment, a pinion gear  152  is fixed on the input shaft  111  so as to rotate integrally therewith. A rack gear  153  meshing with the pinion gear  152  is fitted so as to move vertically. An elongate transmission shaft  154  is fixed vertically on a lower end of the rack gear  153  so as to reach a position near a floor surface. A lower end of the transmission shaft  154  is fitted in a rotatable manner on a step plate  155   a  of a step pedal  155 . The step pedal  155  is disposed on the floor surface.  
      A compression spring  156  is attached between the step plate  155   a  and a bottom plate  155   b  of the step pedal  155 . The compression spring  156  keeps its original state such that the rack gear  153 , the pinion gear  152  and the gear  134  return to their original positions shown in  FIG. 15 , when no force is applied to the step plate  155   a.  If an operator presses the step plate  155   a  by his or her foot from the above state, the rack gear  153  is vertically lowered together with the transmission shaft  144 . Then, the pinion  152  is rotated in an arrow direction A. Thus, the input shaft  111  and the gear  134  are rotated integrally so as to turn the rotary shaft  133  in an arrow direction B and the drive shaft  105   a  in an arrow direction C. Consequently, the second pulley  109  fitted on the drive shaft  105   a  is rotated so as to wind up the wire  109 , thereby compressing the coil spring  116 .  
      In the seventh embodiment, a gear ratio of the pinion gear  152  and the rack gear  153  is set such that the input shaft  111  is rotated about 150 degrees when the rack gear  153  is lowered about 10 cm. Then, if an operator presses the step plate  155   a  by about 10 cm, one end of the toothless part  134   a  of the gear  134  arrives at the meshing position of the gear  134  and the gear  132 . Thereby, the gear  132  runs idle so that the coil spring  116  is released. Consequently, the drive shaft  105   a  and the rotary shaft  133  are rotated in reverse directions to arrow directions, respectively. Thus, the drive roller  105  is rotated integrally with the drive shaft  105   a  so as to feed out and drive the conveyor belt  104  in an arrow direction D. If the operator releases his or her pressing force after pushing the step plate  155   a  within the range of about 10 cm, the step plate  155   a  returns a little by a repulsive force of the compression spring  156 . Then, the rack gear  153  is raised a little. Thus, it is possible to rotate the input shaft  111 , the rotary shaft  133  and the drive shaft  105   a  in the reverse directions to the arrow directions, respectively, thereby inching the conveyor belt  104 .  
      As described above, in the belt conveyor  151  according to the seventh embodiment, the coil spring  116  is compressed only when needed. Then, the conveyor belt  104  can be driven more safely by use of the elastic force stored in the coil spring  116 . Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, since the operator is free to use both hands, he or she can perform another work at the same time, while driving the belt conveyor  151 .  
     Eighth Embodiment  
      An eighth embodiment of the invention is described referring to  FIG. 16 .  FIG. 16  is an enlarged left side elevation view showing a drive section of a belt conveyor according to an eighth embodiment of the invention. Most of components of a belt conveyor according to the eighth embodiment are similar to those of the fifth to seventh embodiments. Therefore, the same reference numerals or characters will be affixed to the same components, elements or parts in order to omit their description.  
      As shown in  FIG. 16 , in the eighth embodiment of the belt conveyor  161 , the input shaft  111  is rotated not by hand power but by foot power, too. However, a step pedal  167  is mounted on a leading end of an input lever  166  in contrast with the seventh embodiment.  
      It is almost impossible to rotate the input lever  166  by about 150 degrees only by foot press. Therefore, a small diameter gear  163  having thirty teeth is fixed on the input shaft  111 . A large diameter gear  164  having one hundred teeth is fixed on a second input shaft  165 . Then, the large gear  164  is meshed with the small gear  163 . The input lever  166  is secured on the second input shaft  165 . Thus, the belt conveyor is structured such that, if the input lever  166  is turned about 45 degrees, the input shaft  111  is rotated about 150 degrees. Accordingly, a third frame  162  becomes large according to increase of a size of a rotating speed increasing mechanism.  
      With the belt conveyor  161  having such structure, if the operator presses the step pedal  167  by his or her foot, the input lever  166  is turned in an arrow direction. Then, the second input shaft  165  and the gear  164  are rotated integrally so as to make the meshed gear  163  rotate in the arrow direction A. Thereby, the input shaft  111  and the gear  134  are integrally rotated so as to turn the rotary shaft  133  in an arrow direction B and the drive shaft  105   a  in an arrow direction C. Consequently, the second pulley  109  attached to the drive shaft  105   a  is rotated to wind up the wire  108  so as to compress the coil spring  116 .  
      If the operator turns the step pedal  167  by about 45 degrees, one end of the toothless part  134   a  of the gear  134  arrives at a meshing position of the gear  134  and the gear  132 . Then, the gear  132  runs idle. Therefore, the coil spring  116  is released so that the drive shaft  105   a  and the rotary shaft  133  are rotated in the reverse directions to the arrow directions, respectively. Consequently, the drive roller  105  is rotated integrally with the drive shaft  105   a  so as to feed out and drive the conveyor belt  104  in an arrow direction D.  
      As described above, in the belt conveyor  161  according to the eighth embodiment, the coil spring  116  is compressed only when needed. Then, the conveyor belt can be driven more safely by use of the elastic force stored in the coil spring  116 . Thus, it is possible to save an energy to a large extent without using any electric power. Moreover, since the operator is free to use both hands, he or she can perform another work at the same time, while driving the belt conveyor  161 .  
      The fifth embodiment is described on an example in which the gear  134  is made of a fiber reinforced plastic or FRP. However, the gear  134  may be made of a normal steep for gears. To the contrary, the other gears  130 ,  131  and  132  may be made of FRP. In the sixth embodiment, the gears  130 ,  131 ,  132  and  147  may be made of FRP. In these cases, there is an advantageous effect that the rotating speed increasing mechanism becomes light and a load applied to the supporting legs  121  lessens.  
      Each of the fifth to eighth embodiments adopts a mechanism mainly composed of the coil spring  116  as an elastic energy storage mechanism. However, the elastic energy storage mechanism is not limited thereto. It may be composed of one using a plate spring, one that supplies compressed air by an air pump into an air cylinder having a stopper operated when it is retracted, one that compresses and expands an air cylinder by an input lever, one that mount a pinion rod on a coil spring or an air cylinder so as to directly rotate it by engagement with a pulley, or the like.  
      In practicing the invention of the fifth to the eighth embodiments, the spring driven belt conveyor is not limited to those of each of the above embodiments in the structure, shape, number, material, dimension, connecting relation or the like of the other components or parts.  
      In embodying the invention of the fifth to the eighth embodiments, the mechanism may be disposed as follows. Specifically, the coil spring  116  is compressed within a range of the compressing limit, while the conveyor belt  104  being restrained from movement. Then, the restraint of the conveyor belt  104  is released by a predetermined button operation so as to make the energy of the coil spring  116  discharged.  
      Particularly, in practicing the invention according to the fifth to the eighth embodiment, in case of one that stores an energy when not used and that outputs it at a burst when needed such as the one that supplies the compressed air into the air cylinder by the air pump, there is a slight recognition for manually driving when using. Moreover, it is possible to store compressed air into an air cylinder.  
      Since the inventive belt conveyor uses no electricity, the inventive belt conveyor according to the fifth to the eighth embodiment is applicable to a watery workplace, for example, a kitchen, a farm workplace under the scorching sun, carrying in a water tank and carrying out of the water tank in which the conveyor is put in water, a paint factory in which explosion or fire is possible in the factory, a cleansing step or a chemical factory using an organic solvent, a clean room in which static electricity is generated by a rotation of a motor and dust is attached to products, an air-conditioned temperature-controlled room that hates heat by a motor, or a food factory that hates leak of an oil or a grease oil. In the kitchen, the inventive belt conveyor according to the fifth to the eighth embodiment requires no waterproof wiring for improving electric insulation of an isolation transformer or the like even in case of delivery and receipt between the kitchen and a service room. Consequently, the belt conveyor becomes inexpensive.  
      When the inventive belt conveyor according to the fifth to the eighth embodiment is not driven, it does not use energy at all. Therefore, the inventive belt conveyor has a energy saving effect in contrast with the conventional belt conveyor that is always operated continuously.  
      The inventive belt conveyor according to the fifth to the eighth embodiments is also applicable to transport between a mixing room and a delivery room of a pharmacy or the like, delivery and receipt between a clean room and an outside, sorting work and transport after sorting in a sorting or grading place of vegetables and fruits, and, as a matter of course, to delivery from labor-intensive workplace in an assembly plant to a main conveyor, assembly and transport of parts in a group unit or the like, transport in a box or case packaged unit, an assembly plant in which layout of machines is frequently carried out, a delivery center in which sorting and delivery or the like is carried out, on-site delivery of food articles and packages when an earthquake or a typhoon is generated, or the like.  
      The preferred embodiments described herein are illustrative and not restrictive, the scope of the invention being indicated in the appended claims and all variations which come within the meaning of the claims are intended to be embraced therein.