CONVEYOR DEVICE

Abstract: A conveyor apparatus 20 according to the present invention comprises a tread guide rail 4 which is provided on a structure 120, and a plurality of treads 2 which moves along the tread guide rail 4. The plurality of treads 2 are connected by a chain 5 having pin rollers 5a. An eccentrically rotatable eccentric crank shaft 8 is connected to a rotation drive unit 6. The eccentric crank shaft 8 is connected to an oscillating body 10 which oscillates in accordance with the eccentric rotation of the eccentric crank shaft 8. The oscillating body 10 is provided with pin roller rolling teeth 11 having a trochoid tooth profile for giving thrust to the pin rollers 5a in accordance with the oscillation of the oscillating body 10.

Description: Technical Field The present invention relates generally to a conveyor apparatus, such as an escalator or a passenger conveyor. More specifically, the invention relates to a conveyor apparatus having a long moving distance. Background Art An escalator as an example of a conveyor apparatus has a plurality of treads which have guide rollers in the front and rear portions thereof. The plurality of treads are designed to be supported by the engagement of each guide roller with a tread guide rail which is installed in a structure, to move in a horizontal direction in the vicinity of the landing stage and head of the escalator while being maintained horizontally, and to move in an ascent or descent direction of about 30 degrees on the way from the vicinity of the landing stage to the vicinity of the head of the escalator. Usually, the plurality of treads are connected to each other by means of a chain. By driving this chain, all of the treads are designed to closely move in synchronism with each other. As a drive unit for driving the chain, a system of a type for driving the end portion of the chain by means of a sprocket is adopted. This system is provided in the vicinity of the landing stage or the head of the escalator. However, in an escalator having a large floor height, the load applied to the chain is large, so that there are some cases where sufficient driving force can not be transmitted only by driving the end portion of the chain. Such a problem is not only limited to escalators, but it is also common to all of conveyor apparatuss having a long moving distance. Conventionally, in order to move a series of long treads in an escalator having a large floor height or a passenger conveyor having a long moving distance, it has been proposed that drive units capable of applying driving force on the way of a long chain (in a portion other than end portions in which the chain turns back) (such drive units are disclosed in, e.g., Japanese Patent Publication Nos. 1986-19551, 1986-41834, 1986-41836 and 1987-9520) are distributed. Each of these drive units for applying driving force on the way of the chain comprises: a motor serving as a driving source; a reduction gear for amplifying driving force by over ten; and a chain driving force transmitting mechanism for transmitting the driving force to a stretching chain. If a sprocket is adopted as the chain driving force transmitting mechanism, the contact ratio decreases since the chain is not wound onto the sprocket. Therefore, as shown in, e.g., FIGS. 17(a) and 17(b), in the chain driving force transmitting mechanism, a chain connected to treads 102 is formed as a toothed chain 105, and a driving side is formed by a driving sprocket 106 having a pin roller 108, so that the chain driving force transmitting mechanism utilizes the engagement of the pin roller 108 with the toothed chain 105. However, the conventional chain driving forces transmitting mechanism 100 shown in FIGS. 17(a), 17(b) requires special components, such as the toothed chain, unlike a simple driving mechanism utilizing a chain sprocket for use in usual escalators. In addition, since the toothed chain uses a long pitch link, the velocity of the end of one pitch of the toothed chain is more ununiform in the turning portion of the toothed chain than the usual chain, so that the toothed chain is turned back by means of a pseudo circular guide rail although the usual chain is turned back by means of a sprocket. Therefore, it is difficult to use an inexpensive standard driving mechanism, which is driven by a circular sprocket rotating at a constant velocity, in the turning portion. The inventor found a reduction gear using a trochoid tooth profile for carrying out a linear driving before the present invention has been made. Such a reduction gear is disclosed in, e.g., Japanese Patent Laid-Open Nos. 5-187502, 6-174043 and 9-105446, and is used in the field of industrial robot, automatic machine and so forth. For example, as shown in FIG. 18, Japanese Patent Laid-Open No. 9-105446 discloses a reduction gear wherein pins 106 are mounted on a translation body 107 at regular intervals (even pitches) along the translation body 107, and if an eccentric crank 108 connected to a motor makes one rotation, an oscillating plate 111 having a trochoid tooth profile 110 makes one oscillation, so that the portion of the trochoid tooth profile 110 moves the pins 106 forward by one pitch at a constant velocity. That is, according to this reduction gear, the translation body 107 moves by one pin pitch per one rotation of the motor. Conventionally, such a mechanism has been utilized as a reduction gear for an industrial robot or the like. DISCLOSURE OF THE INVENTION It is therefore an object of the present invention to provide a conveyor apparatus which can be applied to an escalator having a large floor height, a passenger conveyor having a long moving distance and so forth and which is capable of being a single driving mechanism serving as two mechanism elements of both a reduction gear and a chain driving force transmitting mechanism which have been conventionally essential for conventional driving mechanisms. It is another object of the present invention to provide a conveyor apparatus which has a distributed driving mechanism using a conventional inexpensive standard conveyor drive unit of a chain sprocket in a chain turning portion and which is capable of being used with conventional drive unit. In order to accomplish these other objects, a conveyor apparatus according to the present invention comprises: a tread guide rail which is provided on a structure; a plurality of treads which move along the tread guide rail; a chain having a pin roller and connecting the plurality of treads in the form of an endless loop; a rotation drive unit which is mounted on the structure; and driving means for converting a rotational motion, which is transmitted from the rotation drive unit via an eccentric shaft, into an oscillating motion of an oscillating body having a trochoid tooth profile, to give thrust to the pin roller which engages the trochoid tooth profile. The driving means preferably comprises: an eccentric crank shaft which is connected to the rotation drive unit and which eccentrically rotates; an oscillating body which is connected to the eccentric crank shaft and which oscillates in accordance with the eccentric rotation of the eccentric crank shaft; and trochoid-shaped pin roller rolling teeth which are provided on an end portion of the oscillating body and which give thrust to the pin roller in accordance with the oscillation of the oscillating body. According to the conveyor apparatus of the present invention, the pin rollers of the chain are arranged at regular intervals (even pitches) by the links of the chain, and are guided on the tread guide rail, so that the pin rollers are arranged in the same state as pins mounted on a translation body at regular intervals (even pitches). When the eccentric crank shaft rotates, the oscillating body oscillates, so that the pin roller contacting the trochoid tooth profile of the oscillating body can move forward by one pitch every one rotation of the eccentric crank shaft. In such a mechanism for converting rotational motion to oscillating motion of the trochoid tooth profile, the chain driving mechanism itself also functions as a reduction gear. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the construction of the first preferred embodiment of a conveyor apparatus according to the present invention; FIG. 2 is a schematic diagram showing the construction of a chain of the conveyor apparatus of FIG. 1; FIG. 3 is a schematic diagram showing the detailed construction of a driving mechanism portion of the conveyor apparatus of FIG. 1; FIG. 4 is an illustration for explaining the principle of operation of pin roller rolling teeth and pin rollers; FIG. 5 is a schematic diagram showing the detailed construction of a driving mechanism portion of the second preferred embodiment of a conveyor apparatus according to the present invention; FIG. 6 is a schematic diagram showing the detailed construction of a driving mechanism portion of the third preferred embodiment of a conveyor apparatus according to the present invention; FIGS. 7(a) to 7(d) are illustrations showing the position of each pin roller rolling teeth while an eccentric crank shaft makes one rotation; FIGS. 8(a) to 8(f) are illustrations showing the movement on each pin roller rolling teeth while an eccentric crank shaft makes one rotation, and the positional relationship between a tread guide rail and a back face supporting plate; FIG. 9 is a schematic diagram the construction of the fourth preferred embodiment of a conveyor apparatus according to the present invention; FIG. 10 is an illustration showing the balance of force applied to a chain of the conveyor apparatus of FIG. 9; FIG. 11 is a sectional view of a driving mechanism of FIG. 9; FIG. 12 is a schematic diagram showing the fifth preferred embodiment of a conveyor apparatus according to the present invention; FIG. 13 is a perspective view showing the construction of a back face supporting roller for backup supporting a chain in the sixth preferred embodiment of a conveyor apparatus according to the present invention; FIGS . 14 (a) , 14 (b) are sectional views showing the details of the back face supporting roller of FIG. 13; FIG. 15 is a perspective view showing a back face supporting circulating wire rope for backup supporting a chain in the seventh preferred embodiment of a conveyor apparatus according to the present invention; FIG. 16 is a sectional view of the back face supporting circulating wire rope of FIG. 15; FIGS. 17(a), 17(b) are schematic diagrams showing the construction of a conventional conveyor apparatus; and FIG. 18 is a schematic diagram showing the basic construction of a reduction gear using a trochoid tooth profile. BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the accompanying drawings, the preferred embodiments of the present invention will be described below. First Preferred Embodiment FIG. 1 is a schematic diagram showing the construction of the first preferred embodiment of a conveyor apparatus according to the present invention. As shown in FIG. 1, the conveyor apparatus 20 in the first preferred embodiment of the present invention is formed as an escalator, and comprises a tread guide rail 4, which is provided on a structure 7 so as to round, and a plurality of treads 2 which moves along the tread guide rail 4. The tread guide rail 4 in this preferred embodiment is formed of a pair of members having a C-shaped cross section, the opening portion of which faces inward (see FIG. 3). The plurality of treads 2 are connected to each other in the form of a loop by means of a pair of chains 5 (on both sides in directions perpendicular to the plane of FIG. 1) having pin rollers 5a. The pin rollers 5a are rotatably mounted on the chain 5 at regular intervals (even pitches) as shown in FIG. 2. The pin rollers 5a in this preferred embodiment is designed to engage the tread guide rail 4 to guide the treads 2 along the tread guide rail 4. That is, each of the pin rollers 5a also serves a forward guide roller for a corresponding one of the treads 2. However, each of rearward guide rollers 50 has a larger diameter than that of each of the pin rollers 5a, and is designed to travel on a rear wheel guide rail 40 which is provided on a structure 120 (see FIG. 3). On the way of the tread guide rail 4, i.e., in a predetermined portion other than end portions in which the tread guide rail 4 turns back, three driving mechanisms 1a, 1b and 1c for transmitting driving force to the chain 5 are arranged so as to be distributed. The tread guide rail 4 is partially removed in portions in which the driving mechanisms 1a, 1b and 1c are arranged. FIG. 3 is a detailed diagram of the portion of the driving mechanism 1a. Since other driving mechanisms 1b and 1c substantially have the same construction as that of the driving mechanism 1a shown in FIG. 3, only the driving mechanism 1a will be described to omit the descriptions of the driving mechanisms 1b and 1c. As shown in FIG. 3, the driving mechanism 1a has an electric motor 7 (rotation drive unit) which is mounted on the structure 120. The electric motor 18 is capable of producing driving force and stop holding force. The electric motor 18 is connected to an eccentric crank shaft 6 via a reduction mechanism 61 of a gear, and the eccentric crank shaft 6 is connected to an eccentric disc 8 at an eccentricity amount of δ (δ1 ∼ δ8). Thus, the eccentric disc 8 is designed to eccentrically rotate about the shaft center of the eccentric shaft 6 at the eccentricity amount of δ. In this preferred embodiment, in addition to the eccentric crack shaft 6, there are provided two idler crank shafts 7, on each of which an eccentric disc 9 being driven so as to eccentrically rotate at the same eccentricity amount of δ as that of the eccentric disc 8 is mounted. The eccentric disc 8 of the eccentric crank shaft 6 is connected to four oscillating plates 10 (10a ∼ 10d) as oscillating bodies which oscillate in accordance with the eccentric rotation of the eccentric disk 8. The four oscillating plates 10 are divided into two pairs of plates, and arranged forward and rearward to extend in the circulating directions of the chain 5. The two oscillating plates 10 arranged forward to extend are connected to the eccentric disc 9 of one of the idler eccentric crank shafts 7, and the two oscillating plates 10 arranged rearward to extend are connected to the eccentric disc 9 of the other idler eccentric crank shaft 7. Each of the oscillating plates 10 is rotatably supported on a corresponding one of the eccentric crank shafts 6 and 7. The relative positional relationship between the four oscillating plates 10 is such a relationship that the phase shifts of their eccentric angles are equally distributed to be 90 degrees. Moreover, each of the four oscillating plates 10 is provided with a mass balance adjusting device 14 capable of adjusting the weight and mounting position of a fine additional weight 14a. On the top and bottom end portions of each of the oscillating plates 10, trochoid-shaped pin roller rolling teeth 11 (11a ∼ 11d) are detachably mounted. However, the structure of the bottom end side of each of the oscillating plates 10 is not shown in FIG. 3 to simplify the figure. The pin roller rolling teeth 11a through lid are arranged so as to be capable of sequentially engaging the pin rollers 5a of the chain 5 in accordance with the oscillation of the oscillating plates 10a through 10d to apply thrust. In this preferred embodiment, the pin roller rolling teeth 11 of the top and bottom end portions of each of the oscillating plates 10 are designed to engage both of the pin rollers 5a on the approach route side 15a and return route side 15b (see FIG. 1) of the reciprocating circulating chain 5, respectively, to apply thrust. The corner portions of the pin roller rolling teeth 11 are rounded to avoid the occurrence of concentrated stress. In this preferred embodiment, each of the oscillating plates 10 is provided with a position fine control function 13 capable of adjusting the mounting positions of the pin roller rolling teeth 11 and the oscillating plates 10 in the circulating directions of the chain 5. The position fine control function 13 can be simply formed of, e.g., a long hole and a bolt. The structure (e.g., a truss structure) 120 is provided with a back face guide plate 12 for guiding the pin rollers 5a on the opposite side (the upper side in the approach route shown in the figure, and the bottom side in the return route (not shown)) to a side on which the pin roller rolling teeth 11 are positioned with respect to the pin rollers 5a. The back face guide plate 12 is arranged so as to correspond to each of the oscillating plates 10 which are divided into two pairs of plates and which are arranged forward and rearward in circulating directions of the chain 5. The back face guide plate 12 is capable of linearly moving in a moving amount of an eccentricity amount of δ or less of the eccentric disc 8 with respect to the eccentric crank shaft 6 in the circulating directions of the chain 5 in accordance with the frictional force on the contacting pin rollers 5a while the pin rollers 5a are sandwiched between the back face guide plate 12 and a corresponding one of the oscillating plates 10. The back face guide plate 12 is provided with a back face guide plate returning device 17, e.g., a spring device, for returning the linearly moved back face guide plate 12 to the original position. In addition, the back face guide plate 12 is formed so as to have such an extent of hardness that it does not damage the pin rollers 5a, and is exchangeable. Referring to FIG. 4, the operation of this preferred embodiment with such a construction will be described below. FIG. 4 is an illustration for explaining the principle of operation of the trochoid-shaped pin roller rolling teeth 11 and the pin rollers 5a. The pin rollers 5a of the chain 5 are mounted at even pitches P as described above, and support thereon the back faces of the pin rollers 5a from the opposite side to the pin roller rolling teeth 11. From this state, as shown in FIG. 4, if the electric motor 19 is driven to cause the rotation of the gear 61 and eccentric crank shaft 6 and the eccentric rotation of the eccentric disc 8, the eccentric disc 9 of the idler eccentric crank shaft 7 is driven so as to eccentrically rotate at the same eccentricity amount, so that the oscillating plate 10 oscillates while being maintained to be parallel to the circulating directions of the chain 5. By the oscillating motion of the four oscillating plates 10 (10a ∼ 10d), the trochoid-shaped pin roller rolling teeth 11 (11a ∼ 11d) sequentially engage the pin rollers 5a to continuously transmit thrust, so that the pin rollers 5a move forward by one pitch P. If the oscillating plates 10 continuously oscillate, the pin roller rolling teeth 11 give thrust to the chain 5 via the pin rollers 5a to drive the chain 5. Furthermore, the electric motor 6 may be an inexpensive geared motor with gears of about one stage. In this case, the reduction mechanism 61 for the electric motor 6 can be omitted. The pin roller rolling teeth 11 also applies force to the pin rollers 5a in a direction other than the moving directions (the circulating directions of the chain 5) when transmitting thrust to the pin rollers 5a. However, since the guide rail 4 is formed of the members having the C-shaped cross section, the movement of the pin rollers 5a, i.e., the movement of the treads 2, is smoothly carried out. By the construction that the pin roller rolling teeth 11 are detachably mounted on the oscillating plate 10, only the pin roller rolling teeth 11 can be detached from the oscillating plate 10 to be exchanged, and only the pin roller rolling teeth 11 can be produced by mass production. Thus, maintenance costs are decreased. Of course, the pin roller rolling teeth 11 and the oscillating plates 10 may be formed of an integral molding. The mounting error of the pin roller rolling teeth 11 on each of the distributed driving mechanisms 1a, 1b and 1c can be easily adjusted by means of the position fine control device 13 shown in FIG. 3. In this preferred embodiment, the pin roller rolling teeth 11 are distributed and arranged forward and rearward in the circulating directions of the chain 5 so that two of the pin roller rolling teeth 11 make a pair, and each of the pairs of the pin roller rolling teeth 11 pushes the pin rollers 5a having a limited width L. Therefore, the corner portions can be sufficiently rounded in comparison with a case where the four pin roller rolling teeth 11 make a set. Thus, it is possible to inhibit the occurrence of concentrated stress due to edge portions. In addition, since the thickness of the pin roller rolling teeth 11 is ensured, it is possible to sufficiently ensure the strength of the pin roller rolling teeth 11, and it is possible to improve the durability and reliability of the pin roller rolling teeth 11. Moreover, since the phase shift of the eccentric angle of each of the four oscillating plates 10a through 10d is equally distributed at 90° , the deviating force between the oscillating plates 10a through 10d is canceled, so that it is possible to inhibit the occurrence of oscillation. If oscillation occurs, the weight and mounting position of the fine additional weight 14a can be changed by means of the mass balance adjusting device 14 shown in FIG. 3, so that it is possible to easily the mass balance. Thus, it is possible to inhibit fatigue failure and mechanical damage due to oscillation. According to this preferred embodiment, the pin roller rolling teeth 11 are provided on both sides of the top and bottom end portions of the oscillating plates 10, so that thrust can be applied to the pin rollers 5a of both of the approach route side 15a and return route side 15b of the reciprocating circulating chain 5. Therefore, the mechanical efficiency of power transmission can be excellent. In this case, only one side of the oscillating plates 10 can be provided with the pin roller rolling teeth 11. By forming the back face guide plate 12 of a material having such an extent of hardness that it is consumed prior to the consumption of the pin rollers 5a, the pin roller 5a is not damaged, so that the frequency of exchange of the chain 5 is reduced. In addition, since the back face guide plate 12 to be consumed is formed of a separate part, it is possible to easily exchange the plate to a new plate. While the pin roller rolling teeth 11 of the oscillating plate 10 push the pin rollers 5a, the back face guide plate 12 for the back face of the pin rollers 5a linearly moves without sliding with the pin rollers 5a, and when the pin roller rolling teeth 11 of the oscillating plate 10 leaves the pin rollers 5a, the back face guide plate 12 returns to the original position by the pressing force of the back face guide plate returning device 17, so that it is possible to prevent wearing due to sliding to improve durability and reliability. While the conveyor apparatus 20 in this preferred embodiment has been constructed as an escalator, the conveyor apparatus 20 may be constructed as a horizontal passenger conveyor. Second Preferred Embodiment Referring to FIG. 5, the second preferred embodiment of a conveyor apparatus according to the present invention will be described below. FIG. 5 is a schematic diagram showing the construction of the portion of a driving mechanism 21 of the second preferred embodiment of a conveyor apparatus according to the present invention. As shown in FIG. 5, in the conveyor apparatus 20 in this preferred embodiment, a chain 5 comprises a large number of pairs of links 5b which have a length corresponding to one pitch between adjacent treads 2 and which are connected to each other. On the front end portion of each of the links 5b, guide rollers 24 separated from pin rollers 5a are provided. Each four of the pin rollers 5a are mounted between the pair of links 5b so as to be arranged at regular intervals when the links 5b are aligned with each other. Only the guide roller 24 engages a tread guide rail 4, and the pin rollers 5a of the chain 5a does not engage the tread guide rail 4. The tread guide rail 4 has a C-shaped cross section, and the guide rollers 24 roll on the peripheral face thereof, so that it is possible to regulate the vertical movement of the guide rollers 24. Thus, the tread guide rail 4 serves as a back face guide plate for guiding the pin rollers 5a of the chain 5 on the opposite side to a side on which pin roller rolling teeth 11 are arranged. Other constructions are substantially the same as those of the first preferred embodiment shown in FIGS. 1 through 3. In the second preferred embodiment, the same reference numbers are given to the same portions as those in the first preferred embodiment shown in FIGS. 1 through 3 to omit the detailed descriptions thereof. According to this preferred embodiment, the links 5b of the chain 5 have the length corresponding to one pitch between adjacent treads 2, it is possible to reduce the number of links. On the other hand, it is possible to easily increase the number of engagements of the oscillating plates 10 with the pin roller rolling teeth 11 by increasing the number of the pin rollers 5a, so that it is possible to easily enhance the ratio of reduction (reduction ratio) utilizing a trochoid tooth profile. Third Preferred Embodiment Referring to FIG. 6, the third preferred embodiment of a conveyor apparatus according to the present invention will be described below. FIG. 6 is a schematic diagram showing the construction of the portion of a driving mechanism 41 of the third preferred embodiment of a conveyor apparatus according to the present invention. As shown in FIG. 6, in the conveyor apparatus 30 in this preferred embodiment, a trochoid-shaped pin roller rolling teeth 31 is formed on a link 5b of a chain 5, and eccentric oscillating pin rollers 32a for giving thrust to the pin roller rolling teeth 31 in accordance with the oscillation of an oscillating plate 10 are provided on the top and bottom end portions of the oscillating plate 10. Other constructions are substantially the same as those in the second preferred embodiment shown in FIG. 5. In the third preferred embodiment, the same reference numbers are given to the same portions as those in the second preferred embodiment shown in FIG. 5 to omit the detailed descriptions thereof. The operation of this preferred embodiment is substantially the same as that of the second preferred embodiment, except that the mounting relationship between the pin rollers 32a and the pin roller rolling teeth 31 is opposite to that in the second preferred embodiment. In the driving mechanism common to the conveyor apparatuss in the first preferred embodiments which have been described above, the distribution of the eccentric phase angle of each of the oscillating plates 10a through 10d connected to the eccentric crank shaft 6, and the arrangement of each of the pin roller rolling teeth 11a through 11d will be described below in more detail. Since the basic components of the driving mechanism are common to those of the driving mechanism 1a of FIG. 3, the same reference numbers as those in FIG. 3 are given thereto to describe them. FIG. 7 is an illustration showing the variation in position of engagement of the pin roller rolling teeth 11a through 11d, which are mounted on each of the oscillating plates 10a through 10d arranged as shown in FIG. 3, with the pin rollers 5a while the crank shaft 6 makes one rotation. The pin roller rolling teeth 11a through 11d have the same trochoid tooth profile. Thus, the cost of producing a complicated trochoid tooth profile is reduced. However, the phases of the trochoid tooth profile are designed to be shifted to change the positions of engagements of the pin roller rolling teeth 11a through 11d with the pin rollers 5a of the chain 5 so that the pin roller rolling teeth 11a through 11d can be meshed with the pin rollers 5a to smoothly move the chain 5 by a distance which is equal to the pitch P of the chain while the eccentric crank shaft 6 makes one rotation. That is, the eccentric phase angles of the oscillating plates 10a, 10b, 10c and 10d are shifted by 90° . Assuming that the eccentric phase angle difference of each of the oscillating plates 10b through 10d with respect to the oscillating plate 10a is ΔΦi, the phase shifts of the trochoid tooth profile of the pin roller rolling teeth 11a through 11d mounted on the oscillating plates 10a through 10d are shifted by Δp = P x ΔΦi/ 360 in the traveling direction of the chain 5 with respect to the relative positional relationship to the pin rollers 5a (P is the pitch of the trochoid tooth profile, and equal to the pitch of the chain 5 in this case). Referring to FIGS 7 (a) to (d), these will be specially described as follows. FIG. 7(a) shows the positions of the respective pin roller rolling teeth 11a through 11d when the angle of rotation of the eccentric crank shaft 6 is 0° or 360° . On the basis of the pin roller rolling teeth 11a, the phase of the trochoid tooth profile of the pin roller rolling teeth 11b having an eccentric phase angle difference of 90° from the pin roller rolling teeth 11a is shifted by P x 1/4 (P x 90 / 360) in the chain traveling direction from the trochoid tooth profile of the pin roller rolling teeth 11a as far as the relative positions to the pin rollers 5a are concerned. Similarly, with respect to the relationship between the pin roller rolling teeth 11b and the pin roller rolling teeth 11c, the eccentric phase angle difference is 90° , so that the phase shift of the trochoid tooth profile with respect to the relative positions to the pin rollers 5a is P x 1/2 (P x 180 / 360). With respect to the pin roller rolling teeth 11d, the phase shift is P x 3/4 (P x 270 / 360). Such a relative phase shift between the trochoid tooth profile and the pin roller 5a does not vary even if the angle of rotation of the eccentric crank shaft 6 is 90° (FIG. 7(b)), 180° (FIG. 7(c)) or 270° (FIG. 7(d)). Therefore, while the eccentric crank shaft 6 makes one rotation, each of the pin roller rolling teeth 11a through 11d can smoothly move the chain 5 by the pitch P in accordance with the oscillation of the oscillating plates 10a through 10d while the positions of engagement with the pin rollers 5a are sequentially changed. In the driving mechanism with the above described construction, the set of the oscillating plates 10a, 10b and the set of the oscillating plates 10b, 10d are distributed forward and rearward to cancel the inertial force during oscillation. Therefore, the inertial force does not act on the eccentric crank shaft 6 and idler concentric crank shaft 8 as an excitation force, so that it is possible to inhibit the occurrence of vibrations and noises. The phase shifts of the trochoid tooth profiles of the pin roller rolling teeth 11a through 11d in the chain traveling direction have been described above. In order to allow the pin roller rolling teeth 11a through 11d to oscillate to apply appropriate thrust to the pin rollers 5a, the tread guide rail 4 and the back face guide plate 12 must appropriately guide the pin rollers 5a, and the pin roller rolling teeth 11a through 11d must be prevented from interfering with the tread guide rail 4 or the back face guide plate 12. Therefore, referring to FIG. 8, the tread guide rail 4 and the back face guide plate 12 will be described below in detail. FIGS 8(a) to 8(f) are illustrations showing the positional relationship between the tread guide rail 4 and the back face guide plate 12 with respect to the set of the pin roller rolling teeth 11a and 11c of the pin roller rolling teeth 11a through 11d. As shown in FIG. 3, the tread guide rail 4 is a guide rail having an U-shaped cross section wherein an upper guide portion 4a and a lower guide portion 4b serve as rolling guide surfaces for the pin rollers 5a. FIG. 8(a) is a plan view of the upper guide portion 4a when the tread guide rail 4 is viewed from the top, and FIGS. 8(b) through 8(e) show the movement of the pin roller rolling teeth 11a and 11c when the eccentric crank shaft 6 is rotated by every 90° . FIG. 8(f) is a plan view showing the lower guide portion 4b of the tread guide rail 4. Furthermore, the set of the pin roller rolling teeth 11b and 11d is not shown in FIG. 8 since it is the same as the set of the pin roller rolling teeth 11a and 11c. The tread guide rail 4 is provided with a discontinuous portion so as not to be positioned just above the pin roller rolling teeth 11a and 11c. The pin roller rolling teeth 11a and 11c are designed to pass through the discontinuous portion of the tread guide rail 4 to oscillate toward the top dead center or the bottom dead center. As shown in FIG. 8(f), the pin roller rolling teeth 11a and 11c oscillate in parallel to the tread guide rail 4, and when the pin roller rolling teeth 11a is positioned at the top dead center or the bottom dead center (see FIG. 8(c) or 8(d)), the phase difference of the pin roller rolling teeth 11a from the pin roller rolling teeth 11c is P/2 in length directions (P is the pitch of the trochoid tooth profile). In order to prevent the pin roller rolling teeth 11a and 11c oscillating in such a phase difference from interfering with the tread guide rail 4, a part of each of end portions of the lower guide portion 4b of the tread guide rail 4, which face each other via the pin roller rolling teeth 11a and 11c of the lower guide portion 4b, is cut out in a rectangular shape to form recessed portions 41a and 41c, so that the lower guide portion 4b has a stepped shape as shown in FIG. 8(f). Each of the recessed portions 41a and 41c is preferably half the width of the lower guide portion 4b, and has a length of at least P/2. In addition, when the pin roller rolling teeth 11a and 11c are positioned at the top dead center or the bottom dead center, respectively, as shown in FIG. 8(c) and 8(e), a recess Δm remains in the recessed portions 41a and 41c, so that the recessed portions 41a and 41c are set so as to overlap with the lower guide portion 4b over a length of 0.28 P at the maximum. Assuming herein that the moving amount of the pin roller rolling teeth 11a and 11c in the traveling direction of the chain 5 is ± δm, this δm is ±0.159 P during the traveling from FIG. 8(b) to FIG. 8(d) at the maximum in the relationship to the pitch P. Therefore, while the pin roller rolling teeth 11a and 11c oscillate, the recess Δm is always ensured, so that the lower guide portion 4b does not interfere with the pin roller rolling teeth 11a and 11b. In addition, the overlapping portion of the lower guide portion 4b with the pin roller rolling teeth 11a and 11c is always ensured. Therefore, even if the tread guide rail 4 has the discontinuous portion, the pin rollers 5a of the chain 5 move continuously and smoothly on the pin roller rolling teeth 11a and 11c from one end portion of the lower guide portion 4b to the other end portion thereof. On the other hand, as shown in FIG. 8(a), a part of each of end portions of the upper guide 4a of the tread guide rail 4, which face each other via the back face guide plate 12, is also cut out in a rectangular shape to form a recessed portion 42 which has a predetermined length ΔS. In the case of the upper guide 4a, each of both end portions of the back face guide plate 12 is also cut out to form a rectangular recessed portion 43. The back face guide plate 12 is connected to the back face guide plate returning device 17 for returning the back face guide plate 12 to a neutral position shown in FIGS. 8(b) and 8(d). The position returning device 17 has a mechanism for holding the position of a rod 17c by means of springs 17a and 17b having the same elastic modulus. If the back face guide plate 12 is dragged by the pin rollers 5a, which are moved by the oscillation of the pin roller rolling teeth 11a and 11c, linearly moves, the back face guide plate 12 can be returned to the original neutral position by the biasing force of the springs 17a and 17b. That is, when the trochoid tooth profiles of the pin roller rolling teeth 11a and 11c move so as to push the pin rollers 5a out as the process from FIG. (b) to FIG. 8(c) or the process from FIG. 8(d) to FIG. 8(e), the back face guide plate 12 is dragged by the movement of the pin rollers 5a to linearly move by a moving amount of δs. By this linear movement (translation motion), the spring 17a of the back face guide plate returning device 17 is compressed, and the spring 17b is pulled. On the other hand, when the trochoid tooth profiles of the pin roller rolling teeth 11a and 11c simply roll and guide the pin rollers 5a as the process from FIG. 8(c) to FIG. 8(d) or the process from FIG. 8(e) to FIG. 8(b), the back face guide plate 12 receives no drag from the pin rollers. Therefore, the spring 17a of the back face guide plate returning device 17 push the back face guide plate 12 back, and the spring 17b pulls the back face guide plate 12 back, so that the back face guide plate 12 can be returned to the neutral position. The upper guide portion 4a of the tread guide rail 4 can alternately overlap with the back face guide plate 12 without interfering therewith if the dimensions of the recessed portions 42 and 42 are set as follows. In a connecting portion in which the upper guide portion 4a overlaps with the back face guide plate 12, it is assumed that the length of each of the recessed portions 42 and 43 is ΔS and the width of the overlapping portion of the upper guide portion 4a of the tread guide rail 4 with the back face guide plate 12 at the neutral position shown in FIG. 8(b) or (d) is Δs. In addition, assuming that the translation moving amount of the back face guide plate 12 dragged by the pin rollers 5 moved by the oscillation of the pin roller rolling teeth 11a and 11c is δs, ΔS-Δs is set to be greater than the translation moving amount δs. By setting so, even if the back face guide plate 12 linearly moves from the neutral position by δs as shown in FIG. 8(c), clearances always remain in the recessed portions 42 and 43, so that it is possible to surely avoid the interference with each other to maintain smooth operation. Fourth Preferred Embodiment Referring to FIGS. 9 and 10, the fourth preferred embodiment of a conveyor apparatus according to the present invention will be described below. FIG. 9 is a schematic diagram showing the construction of the fourth preferred embodiment of a conveyor apparatus according to the present invention. In the conveyor apparatus in this fourth preferred embodiment, a tread guide rail 4 provided on a structure 120, and a plurality of treads 2 moving along the tread guide rail 4 are the same as those in the above described third preferred embodiment. Similar to the conveyor apparatus in the first through third preferred embodiments, the plurality of treads 2 are connected to each other in the form of a loop by means of a pair of chains 5 (on both sides in direction perpendicular to the plane of FIGS. 7 (a) to 7(d)) having pin rollers 5a. Driving mechanisms for driving the chain 5 are distributed and arranged on the way of the tread guide rail 4 at regular intervals. The basic constructions of the driving mechanism 1a and 1b are the same as that of the driving mechanism shown in FIG. 3, so that the same reference numbers are given to the same components to omit the detailed descriptions thereof. The conveyor apparatus in this fourth preferred embodiment is constructed as an escalator having a difference in level in both gates. The housings 52a and 52b of the driving mechanisms 1a and 1b are installed on the structure 120, which is inclined at the same gradient as that of the tread guide rail 4, via supporting portions 53a and 53b, respectively, so as to be slidable in the moving direction of the treads 2. In order to apply constant force to the whole driving mechanisms 1a and 1b, which are installed so as to be slidable, from the structure 120, chain tension biasing means 54a and 54b for increasing the tension of the chain 5 are provided. On the lower turning portion 55 of upper and lower turning portions of the treads 2, an initial tension adding means 56 for adding initial tension to the chain is provided. The chain tension biasing means 54a, 54b and the initial tension adding means 56 can utilize the biasing force of springs or the like to bias the tension of the chain 5, and can remove sag even if the initial extension of the chain 5 or the like occurs. FIG. 10 is a diagram schematically showing a balanced state of force acting the chain 5. In FIG. 10, for convenience of explanation, reference number 57a denotes a chain from the lower turning portion to the lower stage driving mechanism 1b, and 57b denotes a chain of a portion above the driving mechanism 1b. In FIG. 10, the balance of force with respect to the lower driving mechanism 1b will be first considered. In FIG. 10, Wbc denotes a gradient angular component of weight of the chain 57b, and Wbd denotes a gradient angular component of weight of the driving mechanism 1b itself, Wini denoting an initial tension applied to the chain 57b from the initial tension adding means 56, and Wlb denoting a gradient angular component of weight of passengers and cargo, which acts on the driving mechanism 1b from the lower turning portion 55 (Wlb will be hereinafter referred to as a variable load weight since it varies in accordance with operation state). These forces act on the chain 57b downwards in parallel. On the other hand, it is assumed that force that the chain tension biasing means 54b biases the chain 57b upward in parallel while the lower driving mechanism 1b drives the chain 57b is Tb. This chain biasing force Tb always acts, the tension of the chain 5 can be managed as follows. That is, if the magnitude of the chain biasing force Tb is set to be substantially equal to the gradient angular component Wbc of weight of the chain 57b and the gradient angular component Wbd of weight of the driving mechanism 1b, the chain tension biasing means 54b can support weight corresponding to the sum Wb (which will be hereinafter referred to as a fixed load weight Wb since it is constant every conveyor apparatus) of the gradient angular component Wbc of weight of the chain 57b and the gradient angular component Wbd of weight of the driving mechanism 1b. Therefore, the fixed load weight Wb is not applied to the chain 57a above the driving mechanism 1b, so that the tension substantially acting on the chain 57a is reduced to Wini + Wlb which is the total of the initial tension Wini applied from the initial tension adding means 56 and the above described variable load weight Wlb. Moreover, also in the balance of force with respect to the upper driving mechanism 1a, if the magnitude of the chain biasing force Ta of the chain tension biasing means 54a is set to be substantially equal to the sum Wa (which will be hereinafter referred to as a fixed load weight Wb since it is constant every conveyor apparatus) of the gradient angular component Wac of weight of the chain 57a and the gradient angular component Wad of weight of the driving mechanism 1a itself, the chain tension biasing means 54a can support the fixed load weight Wa which is the total of the gradient angular component Wac of weight of the chain 57a and the gradient angular component Wad of weight of the driving mechanism 1b. Therefore, the fixed load weight Wa is not applied to a portion of the chain 57c above the driving mechanism 1a, so that the actually acting tension can be reduced to the sum of the above described tension Wini + Wlb, which acts from the chain 57a, and the variable load weight Wlb which a gradient angular component of the total weight of passengers and cargo from the driving mechanism 1b to the driving mechanism 1a, i.e., to Wini + Wla + Wlb. In short, as the whole chain 5, the chain tension biasing means 54a and 54b bear the fixed load weights Wa and Wb, so that the load applied to the chain can be lighten by that weights. Furthermore, since the variable load weights Wla and Wlb are zero when no load is applied, at least the initial tension Wini is applied to the whole chain 5. In the above described preferred embodiments, the load of the chain 5 is lightened by additionally providing the chain tension biasing means 54a and 54b in the driving mechanisms 1a and 1b, respectively. FIG. 11 shows a driving mechanism 1a or 1b wherein a variable load weight Wla or Wlb is supported on a pin roller rolling teeth. In this case, the driving mechanisms 1a and 1b have the same construction. Therefore, referring to FIGS. 8 (a) to 8(f), the driving mechanism 1a will be described below. Furthermore, in FIG. 11, the same reference numbers as those in FIG. 3 denote the same components. In FIG. 11, Δt denotes a distance between the axis of the eccentric crank shaft 6 and the approach route side chain 15a, and Δr denotes a distance between the axis of the eccentric crank shaft 6 and the return route side chain 15b. In this case, Δt is different from Δr, and the distance Δr to the return route side is longer than Δt. On the oscillating plate 10, a pair of trochoid-shaped pin roller rolling teeth 11 are distributed forward and rearward on each of the approach route side and the return route side. Each of the pin roller rolling teeth 11 are mounted on the oscillating plate 10 so as to maintain the engagement with the pin rollers 5a of the chain 5. Thus, in the driving mechanism for converting the oscillating motion of the oscillating plate 10 into thrust for the chain by means of the trochoid-shaped pin roller rolling teeth, the relative position of the eccentric crank shaft 8 with respect to the approach route side chain 15a and the return route side chain 15b can be freely set, so that the design layout is flexible. In particular, the size of the driving mechanism in height direction can be easily decreased. In addition, the gradient angular components of the fixed load weight and variable load weight applied to the return route side chain 15b can be supported on the approach route side pin roller rolling teeth 11. The gradient angular components of the fixed load weight and variable load weight applied to the approach route side chain 15a can also be supported on the return route side pin roller rolling teeth 11. Therefore, the whole weights of the chains 15a and 15b can be shared by the approach route side pin roller rolling teeth 11 and the return route side pin roller rolling teeth 11, respectively, so that it is possible to lighten the load applied to the chains 15a and 15b. Fifth Preferred Embodiment Referring to FIG. 12, the fifth preferred embodiment of a conveyor apparatus according to the present invention will be described below. FIG. 12 is a diagram schematically showing the construction of the conveyor apparatus 60 in the fifth preferred embodiment. Similar to the conveyor apparatus 20 shown in FIG. 1, the conveyor apparatus 60 has a distributed driving mechanism wherein the driving mechanisms 1a through 1c are distributed and arranged on the way of the chain 5 at regular intervals. The construction of each of the distributed driving mechanisms 1a through 1c is the same as that of the driving mechanism 1a shown in FIG. 3, so that the descriptions thereof are omitted. The difference between the conveyor apparatus 60 in this fifth preferred embodiment and that in any one of the above described preferred embodiments is that a driving mechanism 62 for driving the returning portion of the chain 5 on the upper floor is provided below the gate on the upper floor, in addition to the distributed driving mechanisms 1a through 1c. This driving mechanism 62 includes a driving motor 63, a sprocket 64, and a chain 65 for transmitting power of the driving motor 63 to the sprocket 64, and is a driving mechanism which is normally adopted in conventional elevators. Since the driving mechanism 62 is associated with the distributed driving mechanisms 1a through 1c for driving the chain 5, the driving force generated from the driving mechanism 62 is sufficient if it can carry weight corresponding to the gradient angular component (corresponding to the above described variable load weight) of the total weight of passengers and cargo from the uppermost distributed driving mechanism 1c to the driving mechanism 62, so that the driving motor 63 having a small capacity can sufficiently cope with it. On the other hand, the driving forces required for the lowermost distributed driving mechanism 1a, the intermediate distributed driving mechanism 1c and the upper distributed driving mechanism 1c are sufficient if each of the driving forces can carry the variable load weight from the turning portion of the chain on the lower floor, the variable load weight from the distributed driving mechanism 1a to the distributed driving mechanism 1b, and the variable load weight from the distributed driving mechanism 1b to the distributed driving mechanism 1c, respectively. Therefore, each of the distributed driving mechanisms 1a through 1c does not require a large capacity of driving motor, and the conveyor apparatus uses the distributed driving mechanisms 1a through 1c together with the inexpensive driving mechanism 62, so that it is possible to reduce the production costs. Sixth Preferred Embodiment Referring to Figs. 13 and 14(a), 14(b), the sixth preferred embodiment of a conveyor apparatus according to the present invention will be described below. FIG. 13 is a perspective view showing a principal part of a driving mechanism 70 of the conveyor apparatus in the sixth preferred embodiment. Links 5b constituting the chain 5 continuously connect the pin rollers 5a at regular intervals (pitch length P). The structure and arrangement of the pin roller rolling teeth 11 are the same as those in the above described preferred embodiments. This sixth preferred embodiment is characterized in that a plurality of back face supporting rollers 72 for rolling the links 5b of the chain 5 are provided above the pin roller rolling teeth 11. The back face supporting rollers 72 are arranged in an elongated box-shaped roller housing 73, the bottom of which is open, at regular intervals δ in the longitudinal directions of the chain 5. In this case, the back face supporting rollers 72 are preferably arranged at intervals of P/2 or less so that the interval δ is shorter than the pitch length P of the chain 5. As shown in FIG. 14(a), each of the back face supporting rollers 72 includes a rotation shaft 72 and a pair of rolling elements 75 which are fixed to the rotation shaft 74. The rotation shaft 74 of each of the back face supporting rollers 72 is rotatably supported on the roller housing 73 via a bearing 76. The distance between the rolling elements 75 is set to be substantially equal to the links 5b which are arranged on both sides of each of the pin rollers 5a of the chain 5, so that the rolling elements 75 can roll on the top edge portions of the links 5b serving as rolling contact surfaces without interfering with the pin rollers 5a. The rolling surface 75a of the outer peripheral surface of each of the rolling elements 75 rolling on the links 5b is coated with a thin film of a material, such as plastic or rubber having a high ability to absorb vibrations and noises. The rolling body 75 is made of a damping steel product which has sufficient rigidity and excellent ability to absorb vibrations and noises. On the other hand, as shown in FIG. 14(b), a cushion ring 77 of a ring-shaped plastic or the like is mounted on the outer peripheral portion of each of the pin rollers 5a of the chain 5, which rolls on the tread guide rail 4, and the pin rollers 5a of the chain 5 are designed to roll on the tread guide rail 4 via the cushion ring 77. In this case, the width of the cushion ring 77 is narrower than the width of the pin roller 5, and the outer peripheral surface on both sides of the cushion ring 77 of the pin roller 5a is designed to be thrust while rolling on the trochoid-shaped teeth of the pin roller rolling teeth 11. Therefore, the body of the pin roller 5a is formed of a steel product having a high rigidity so as not to be deformed, unlike the material of the cushion ring 77. The pin roller rolling teeth 11 require sufficient rigidity similar to the pin rollers 5a, and are made of a damping steel product, which has sufficient rigidity and which has vibration absorbing effects, so as to be able to absorb vibrations and noises which are generated when thrust is given to the pin rollers 5. The operation of the driving mechanism 70 of the conveyor apparatus in the sixth preferred embodiment will be described below. In FIG. 13, while the pin roller rolling teeth 11 engage the pin rollers 5a of the chain 5 to give thrust to the chain 5 in accordance with the oscillation of the pin roller rolling teeth 11, the back face supporting roller 72 backup-supports thereon the chain 5 from the opposite side to the pin roller rolling teeth 11 while rolling the links 5b of the chain 5. That is, assuming that force acting on the chain 5 from the pin roller rolling teeth 11 is F, the back face supporting roller 72 held on the roller housing 73 receives a vertical drag N, which is a component in a direction perpendicular to the traveling direction of the chain 5, with respect to the force F while rolling on the links 5b of the chain 5, and push the chain 5 against the pin roller rolling teeth 11 by its reaction force N'. Therefore, since it is possible to prevent sliding from occurring between the pin rollers 5a and the trochoid-shaped teeth of the pin roller rolling teeth 11 engaged therewith, structural work loss can not only be reduced, but the pin rollers 5a can also tightly hold thrust given from the pin roller rolling teeth 11, so that it is possible to maintain the mechanism principle that the pin roller rolling teeth 11 having trochoid-shaped teeth move the pin rollers 5a at a constant velocity. In this preferred embodiment, the interval δ between the plurality of back face supporting rollers 72 held on the roller housing 73 is shorter than the pitch length P of the links 5b of the chain 5, so that moment generated by the vertical drag N around the back face supporting rollers 72 does not increase. Therefore, the reaction force N' for backup supporting the pin rollers 5a in the front and rear portions of each of the back face supporting rollers 72 is not greater than the vertical drag N, so that it is not required to take measures to cope with the reinforcement of the tread guide rail 4. In addition, since the rolling surface of the rolling element 75 of the back face supporting roller 72 is coated with plastic or the like, mechanical shock intermittently applied to the rolling element 75 due to the vertical drag N is effectively absorbed. Moreover, since the cushion ring 77 is mounted on the pin roller 5a, mechanical shock transmitted from the tread guide rail 4 is reduced by the cushion ring 77, so that the occurrence of vibrations and noises is inhibited. Seventh Preferred Embodiment Referring to FIGS. 15 and 16, the seventh preferred embodiment of a conveyor apparatus according to the present invention will be described below. The difference between the seventh preferred embodiment and the sixth preferred embodiment is that an endless loop back face supporting means is provided in place of the back face supporting roller 72. FIG. 15 is a diagram showing an endless loop back face supporting means for backup supporting thereon the chain 5 from the opposite side to the pin roller rolling teeth 11 in the driving mechanism of a conveyor apparatus 80. Furthermore, in FIG. 15, the same reference numbers are given to the same components as those in FIG. 13 to omit the detained descriptions thereof. The back face supporting means includes an elliptical back face supporting guide 81, and a back face supporting wire rope body 82 which extend along the outer peripheral portion of the back face supporting guide 81 so as to form an endless loop. The back face supporting guide 81 is mounted on a supporting member 83, which extends from the structure 120, so as to be parallel to the chain 5. The back face supporting wire rope body 82 comprises wire rope links 84 which are continuously connected to each other by guide rollers 85 so as to an endless loop. Each of the guide rollers 85 is rotatably mounted, and is designed to engage a peripheral groove 82, which is formed in the outer peripheral portion, while rolling on the outer peripheral portion of the back face supporting guide 81 as shown in FIG. 16. In the back face supporting wire rope body 82, a series of lower wire rope links 84 are designed to contact the links 5b of the chain 5 from the opposite side to the pin roller rolling teeth 11. Therefore, the back face supporting wire rope body 82 tightly supports thereon the chain 5 while circulating and moving in accordance with the movement of the chain 5. That is, if the vertical drag N of a component in a direction perpendicular to the traveling direction of the chain 5, of force F received by the pin roller 5a of the chain 5 from the pin roller rolling teeth 11, acts on the wire rope link 84, the guide roller 85 supported on this wire rope link 84 receives vertical reaction force N' while rolling, and the reaction force N' also pushes the wire rope link 84 against the chain 5. Therefore, it is possible to prevent sliding from occurring between the pin roller 5a and the trochoid-shaped teeth of the pin roller rolling teeth 11 engaged therewith, so that it is possible to reduce structural work loss due to friction force and heat generation. Furthermore, in order to reduce mechanical shock due to the vertical drag intermittently acting via the chain from the pin roller rolling teeth 11, the wire rope link 84 of the back face supporting wire rope body 82 is preferably formed of a damping steel product which has sufficient rigidity and which has an ability to absorb vibrations and noises. The portion of the wire rope link 84 contacting the link 5b of the chain 5 is preferably coated with a thin film of a plastic or the like which absorbs vibrations and noises.

Claims: A conveyor apparatus comprising a tread guide rail (4) which is provided on a structure, a plurality of treads (2) which move along said tread guide rail (4), a chain (5) for connecting said plurality of treads (2) in the form of an endless loop, a rotation drive unit (7) which is mounted on said structure and a driving means (1a, 1b, 1c) for driving the chain (5), characterized in that the driving means (1a,1b,1c) is configured to convert a rotational motion which is transmitted from said rotation drive unit (7) via an eccentric shaft (6), into an oscillating motion of an oscillating body (10) to give thrust to said chain (5) from said oscillating body (10) via a pin roller (5a), which is provided on one of said oscillating body (10) and said chain (5), and a trochoid tooth profile (11) which engages said pin roller (5a). A conveyor apparatus as set forth in claim 1, wherein said driving means (1a, 1b, 1c) comprises: an eccentric crank shaft (6) which is connected to said rotation drive unit (7) and which eccentrically rotates; an oscillating body (10) which is connected to said eccentric crank shaft (6) and which oscillates in accordance with the eccentric rotation of said eccentric crank shaft (6); and trochoid-shaped pin roller rolling teeth (11) which are provided on an end portion of said oscillating body (10) and which give thrust to said pin roller (5a) in accordance with the oscillation of said oscillating body (10). A conveyor apparatus as set forth in claim 1, wherein said driving means (1a,1b,1c) comprises: trochoid-shaped pin roller rolling teeth (31) which are provided on a plurality of links constituting said chain (5); an eccentric crank shaft (6) which is connected to said rotation drive unit (7) and which eccentrically rotates; an oscillating body (10) which is connected to said eccentric crank shaft (6) and which oscillates in accordance with the eccentric rotation of said eccentric crank shaft (6); and an eccentrically oscillating pin roller(32a) which is provided on an end portion of said oscillating body (10) and which gives thrust to said pin roller rolling teeth (31) in accordance with the oscillation of said oscillating body (10). A conveyor apparatus as set forth in claim 1, wherein said driving means (1a,1b,1c) is a distributed driving mechanism which comprises a plurality of said driving means (1a,1b, 1c) distributed and arranged along a linearly extending chain (5). A conveyor apparatus as set forth in claim 1, wherein said tread guide rail (4) comprise a pair of members which has a C-shaped cross section and which has an opening portion directed downward. A conveyor apparatus as set forth in claim 1 or 5, wherein said pin roller (5a) engages said tread guide rail (4). A conveyor apparatus as set forth in claim 1, wherein a back face guide plate (12) for guiding said pin roller (5a) on the opposite side to a side on which said pin roller rolling teeth (11) are positioned with respect to said pin roller (5a) is provided on said structure (7) so as to extend along said tread guide rail(4). A conveyor apparatus as set forth in claim 7, wherein said back face guide plate (12) has such an extent of hardness that said back face guide plate does not damage said pin roller (5a). A conveyor apparatus as set forth in claim 8, wherein said back face guide plate (12) is exchangeable. A conveyor apparatus as set forth in any one of claims 7 through 9, wherein said back face guide plate (12)is linearly movable in the circulating direction of said chain (5)by a moving amount which is not greater than the eccentricity amount (δ) of said eccentric crank shaft (6), and which further comprises a back face guide plate returning device (17) for returning said back face guide plate (12) to the original position when said back face guide plate (12) linearly moves. A conveyor apparatus as set forth in claim 1 or 2, wherein said chain (5) has a plurality of links (5b) having a length which is equal to the pitch (P) of said plurality of treads(2), and a tread guide roller (24) engaging said tread guide rail (4) is provided on an end portion of each of said links (5b), said pin roller (5a) being provided on each of said links (5b). A conveyor apparatus as set forth in claim 2, wherein said pin roller rolling teeth (11) are detachably mounted on said oscillating body (10). A conveyor apparatus as set forth in claim 12, wherein said pin roller rolling teeth (11) or said oscillating body (10)are provided with a position fine control device (13) capable of adjusting the mounting positions of said pin roller rolling teeth (11) and said oscillating body (10) in the circulating direction of said chain (5). A conveyor apparatus as set forth in claim 2, wherein a plurality of oscillating bodies (10), each of which is the same as said oscillating body, are combined with each other via an idler eccentric crank shaft (7) to be distributed and arranged forward and rearward in the circulating direction of said chain (5) A conveyor apparatus as set forth in claim 14, wherein said plurality of oscillating bodies (10)are arranged so that the phase shift between the eccentric angles of adjacent two of said plurality of oscillating bodies (10) is equal to another, and at least one of said plurality of oscillating bodies (10)is provided with a mass balance adjusting device (14) capable of adjusting the weight and mounting position of a fine additional weight(14a). A conveyor apparatus as set forth in claim 14, wherein pin roller rolling teeth (11) engaging both of an approach route side and return route side of said chain (5) reciprocating and circulating is mounted on each of said oscillating bodies (10) to give thrust to a pin roller (5a) of each of said approach route side and return route side of said chain (5). A conveyor apparatus as set forth in claim 16, wherein said eccentric crank shaft (6) connected to said oscillating bodies (10) is arranged at a position at which the distance between said eccentric crank shaft (6) and said chain (15a) on said approach route side is different from the distance between said eccentric crank shaft (6) and said chain (15b) on said return route side, and said pin roller rolling teeth (11) mounted on both of said approach route side and said return route side (15a,15b) have the same tooth profile to maintain the engagement of said chain with said pin roller (5a). A conveyor apparatus as set forth in claim 17, wherein a tread guide roller (24) engaging said tread guide rail (4) is provided on an end portion of each of said links (5b). A conveyor apparatus as set forth in claim 12, wherein a plurality of oscillating bodies (10), each of which is the same as said oscillating body, are combined with each other to be connected to said eccentric crank shaft(6) so that the eccentric phase angle of each of said oscillating bodies (10) is shifted by an angle which is obtained by substantially equally dividing 360°. A conveyor apparatus as set forth in claim 19, wherein said oscillating bodies (10) are arranged so as to be alternately distributed in forward and rearward sets in the traveling direction of said chain in accordance with the magnitude of said eccentric phase angle. A conveyor apparatus as set forth in claim 20, wherein said pin roller rolling teeth (11) mounted on each of said oscillating bodies (10) have the same trochoid tooth profile, said pin roller rolling teeth (11) being arranged in each of said oscillating bodies (10) in a phase difference in the traveling direction of said chain (5) so as to move forward said pin roller (5a) by a pitch P of said teeth when said crank shaft (6) makes one rotation. A conveyor apparatus as set forth in claim 5, wherein said tread guide rail (4) has a stepped shape portion, said stepped shape portion having a recessed portion (41a,41c)for avoiding the interference with said pin roller rolling teeth (11a,11c), and a portion which always overlap with said pin roller rolling teeth (11a,11c). A conveyor apparatus as set forth in claim 10, wherein each of said tread guide rail (4) and said back face guide plate (12) has a recessed portion(42) for avoiding the interference of said tread guide rail (4) with said back face guide plate (12), said tread guide rail (4) overlapping with said back face guide plate (12) via said recessed portion (42). A conveyor apparatus as set forth in claim 2 or 3, which further comprises: means (53a,53b)for supporting said driving mechanism (1a,1b) so that said driving mechanism(1a,1b) is slidable in the traveling direction of said chain(5); mean (54a,54b) for biasing said driving mechanism (1a,1b) in a direction in which tension is applied to said chain (5); and initial tension adding means (56), arranged in a turning portion of said cain(5), for adding initial tension to said chain (5). A conveyor apparatus as set forth in claim 4, wherein a sprocket (64) engaging a turning portion of said chain (51), and a driving part having a driving motor (63) for driving said sprocket(64), together with said distributed driving mechanism (1a, 1b,1c), are provided. A conveyor apparatus as set forth in claim 7, which further comprises a plurality of back face supporting roller (72) which is rotatably supported on said structure and which rolls along a link (5b) for connecting said pin roller (5a) of said chain (5) in the opposite side to a side in which said pin roller rolling teeth(11) are arranged, in place of said back face guide plate (12). A conveyor apparatus as set forth in claim 26, wherein the interval of said back face supporting roller (72)is set to be 1/2 or less with respect to the pitch length P of said link (5b) of said chain (5). A conveyor apparatus as set forth in claim 26, wherein a coating layer of a material having an ability to absorb vibrations is formed on a rolling surface (75a)of the outer peripheral surface of said back face supporting roller (72). A conveyor apparatus as set forth in claim 28, wherein the body of said back face supporting roller (72) is formed of a damping steel product. A conveyor apparatus as set forth in claim 26, wherein a cushion ring (77) forming rolling surfaces to said tread guide rail (4) is mounted on the outer peripheral surface of said pin roller (5a) of said chain (5), said rolling surfaces to said pin roller rolling teeth (11) being formed on both sides of said cushion ring (77). A conveyor apparatus as set forth in claim 26, which further comprises: a back face supporting wire rope body (82) formed by connecting wire rope links (84), which contact links (5b)for connecting said pin rollers (5a) of said chain (5) on the opposite side to a side on which said pin roller rolling teeth (11) are arranged, via a guide roller (85) in the form of an endless loop; and a back face supporting guide (81) for guiding the circulating movement of said back face supporting wire rope body (82) by the rolling of said guide roller (85), in place of said back face supporting roller(72). A conveyor apparatus as set forth in claim 31, wherein a coating layer of a material having an ability to absorb vibrations is formed on a surface of each of said wire lope links (84)contacting said link (5b)of said chain (5). A conveyor apparatus as set forth in claim 32, wherein said wire rope links (84) are formed of a damping steel product.

Inventors: ISHIKAWA YOSHINOBU, OGIMURA YOSHIO, OOKUBO MEGUMI, ISHIKAWA, YOSHINOBU, OGIMURA, YOSHIO, OOKUBO, MEGUMI
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 2000
Main classification: B66B23
IPC codes: B66B23