Abstract:
A carrier type conveying apparatus capable of solving a problem in a conventional conveying apparatus wherein a conveying carriers ( 1 ) stop abnormally, comprising a rear-pushing traveling district ( 3 ) having, at its inlet, a rear-pushing drive means ( 5 A) propelling the conveying carriers ( 1 ) at a constant speed and, at its outlet, a speed control drive means ( 5 B) for sending out the conveying carriers ( 1 ) at the constant speed and a high-speed traveling district ( 4 ). The conveying apparatus comprises carrier connection systems (carrier connection means ( 9 ), connection engagement means ( 10 ), connection release means ( 11 )). When the conveying carriers ( 1 ) travel in the high-speed traveling district ( 4 ), the connection of the conveying carriers ( 1 ) adjacent to each other in the longitudinal direction by the carrier connection systems is disabled. Only when the conveying carriers ( 1 ) travel in the rear-pushing traveling district ( 3 ), the conveying carriers ( 1 ) in the longitudinal direction are connected to each other by the carrier connection system to prevent the conveying carriers ( 1 ) in contact with each other at their end parts from being separated a specified distance or longer from each other.

Description:
TECHNICAL FIELD 
   The present invention relates to a carrier type conveying apparatus including a rear-pushing traveling district for conveying carriers, to be used as a work line, and a high-speed traveling district to be used as a return line for returning the conveying carriers that have come out from the rear-pushing traveling district to an inlet of the rear-pushing traveling district, and a conveying carrier connection system of the carrier type conveying apparatus. 
   BACKGROUND ART 
   The rear-pushing traveling district of the carrier type conveying apparatus described above is provided with, at its inlet, a rear-pushing drive means for propelling the conveying carriers at a constant speed, and at its outlet, a speed control drive means for sending out the conveying carriers at a constant speed, and is known by, for example, Japanese Published Unexamined Patent Application No. Hei-05-170327. There is also known a constitution of a trolley type conveying traveling body in which, for example, as described in Japanese Published Unexamined Patent Application No. Hei-03-42370, connection means for connecting conveying traveling bodies to each other are provided and an after conveying traveling body is pulled by a fore conveying traveling body to travel. 
   SUMMARY OF THE INVENTION 
   In the carrier type conveying apparatus including the rear-pushing traveling district constituted as described above, the conveying carriers traveling in the rear-pushing traveling district form a continuous work floor by bringing their end parts into contact with each other, an operator who transfers onto the conveying carriers can perform operations to attach parts to objects to be conveyed loaded on the conveying carriers, and the operator can freely transfer onto other adjacent conveying carriers and change the conveying objects to be operated. Thus, the rear-pushing traveling district can be utilized as a work line, however, in this status of use, if the rear-pushing drive means provided at the inlet of the rear-pushing traveling district malfunctions and it becomes impossible to send out the following conveying traveling bodies that arrived at the rear-pushing traveling district into the rear-pushing traveling district at a constant speed, all of the conveying carriers in the rear-pushing traveling district except for the leading conveying carrier which is about to be sent out into the high-speed traveling district on the lower route by the speed control drive means provided at the outlet of the rear-pushing traveling district, are not pushed from the rear side and stop. 
   If this situation occurs, even when the operation for the conveying object that is being operated in the rear-pushing traveling district is finished, this object cannot be sent to the high-speed traveling district on the lower route, and this has a crucial harmful influence on a work schedule. Furthermore, between the leading conveying carrier which is about to be sent into the high-speed traveling district on the lower route and the conveying carrier immediately after the leading one, a gap arises which expands gradually, and other conveying carriers in the rear-pushing traveling district slightly advance due to inertia and cause gaps therebetween, so that operators transferring onto the conveying traveling bodies may be caught in the gaps and fall down, and this may lead to a drop accident from the gaps between the carriers. 
   Therefore, it is considered that the connection means as described in the Patent Japanese Published Unexamined Patent Application No. Hei-03-42370 is introduced in the conventional carrier-type conveying apparatus described in the Japanese Published Unexamined Patent Application No. Hei-05-170327 so that the fore and after conveying carriers adjacent to each other in the rear-pushing traveling district are connected to each other and, even if the rear-pushing drive means provided at the inlet of the rear-pushing traveling district as described above malfunctions and it becomes impossible to send the following conveying carriers which arrived at the rear-pushing traveling district into the rear-pushing traveling district, the conveying carriers in the rear-pushing traveling district are pulled to travel so as to be sent out from this rear-pushing traveling district by the leading conveying carrier which is about to be sent into the high-speed traveling district on the lower route by the speed control drive means provided at the outlet of the rear-pushing traveling district. However, the conventional connection means as described in the Patent Document 2 automatically engages and connects the fore and after conveying carriers when the fore and after conveying carriers approach each other. 
   Therefore, in the constitution in which the conventional connection means as described in Japanese Published Unexamined Patent Application No. Hei-03-42370 is simply introduced in the conventional carrier type conveying apparatus described in Japanese Published Unexamined Patent Application No. Hei-05-170327, the connection between the fore and after conveying carriers made by the connection means is released at the outlet of the rear-pushing traveling district and the conveying carriers are successively sent into the high-speed traveling district on the lower route, and even if an appropriate distance can be secured between the fore and after the conveying carriers in this high-speed traveling district, when the drive means which drives the conveying carriers at a high speed in the high-speed traveling district malfunctions and one conveying carrier stops in the high-speed traveling district, the following conveying carriers are connected one after another to this stopping conveying carrier by the connection means. Therefore, when the drive means which had malfunctioned is recovered by means of repairing and starts working, although the conveying carriers should be driven at a high speed while maintaining appropriate intervals between conveying carriers in principle, many conveying carriers waiting on the lower route than the recovered drive means are integrally pulled and driven at a high speed while connected together in a row, and this harmfully influences the sending into the rear-pushing traveling district. 
   An object of the invention is to provide a conveying carrier connection system in a carrier type conveying apparatus capable of solving the above-described conventional problem, which includes, in a traveling route of conveying carriers ( 1 ), a rear-pushing traveling district ( 3 ) having, at its inlet, a rear-pushing drive means ( 5 A) for propelling the conveying carriers ( 1 ) at a constant speed and, at its outlet, a speed control drive means ( 5 B) for sending out the conveying carriers ( 1 ) at a constant speed and a high-speed traveling district ( 4 ) in which the conveying carriers ( 1 ) that came out from the rear-pushing traveling district ( 3 ) are made to travel at a high speed, and a carrier connection system (carrier connection means ( 9 ), connection engagement means ( 10 ), and connection release means ( 11 )) which connects the fore and after adjacent conveying carriers ( 1 ), wherein when the conveying carriers ( 1 ) travel in the high-speed traveling district ( 4 ), the connection between the fore and after conveying carriers ( 1 ) by the carrier connection system is disabled, and only when the conveying carriers ( 1 ) travel in the rear-pushing traveling district ( 3 ), the fore and after conveying carriers ( 1 ) are connected to each other by the carrier connection system to prevent the conveying carriers ( 1 ) in contact with each other at their end parts from being separated a specified distance or longer from each other. 
   A second aspect of the invention provides a carrier type conveying apparatus preferable for carrying out the above-described connection system for conveying carriers in a carrier-type conveying apparatus. This carrier type conveying apparatus includes, as in the second aspect, in a traveling route of conveying traveling bodies ( 1 ), a rear-pushing traveling district ( 3 ) having, at its inlet, a rear-pushing drive means ( 5 A) for propelling the conveying carriers ( 1 ) at a constant speed and, at its outlet, a speed control drive means ( 5 B) for sending out the conveying carriers ( 1 ) at a constant speed and a high-speed traveling district ( 4 ) in which the conveying carriers ( 1 ) that came out from the rear-pushing traveling district ( 3 ) are made to travel at a high speed, and a carrier connection system ( 9 ,  10 , and  11 ) which connects the fore and after adjacent conveying carriers ( 1 ), wherein the carrier connection system includes carrier connection means ( 9 ), a connection engagement means ( 10 ) provided on the inlet side of the rear-pushing traveling district ( 3 ), and a connection release means ( 11 ) provided on the outlet side of the rear-pushing traveling district ( 3 ), the connection engagement means ( 10 ) switches the carrier connection means ( 9 ) at the inlet of the rear-pushing traveling district ( 3 ) to connect the fore and after conveying carriers ( 1 ) in contact with each other at their end parts, and the connection release means ( 11 ) switches the carrier connection means ( 9 ) at the outlet of the rear-pushing traveling district ( 3 ) to release the connection between the fore and after conveying carriers ( 1 ) and be unable to connect the fore and after conveying carriers ( 1 ) in the high-speed traveling district ( 4 ). 
   To carry out the carrier-type conveying apparatus of the invention constituted as described above, in detail, according to a third aspect, the carrier connection means ( 9 ) includes a connected part ( 33 A) provided on either one of the front and rear end parts of each conveying carrier ( 1 ) and a movable connector ( 33 B) provided on the other of the front and rear end parts of each conveying carrier ( 1 ), and the movable connector ( 33 B) can be freely switched between a connecting position and a connection releasing position and formed into a shape so as to be held at the connecting position by an urging force and so as not to automatically engage with the connected part ( 33 A) when conveying carriers ( 1 ) approach each other while the movable connector is at the connecting position, and the connection engagement means ( 10 ) switches the movable connector ( 33 B) at the connecting position to the connection releasing position and then returns the movable connector ( 33 B) to the connecting position in a state that the end parts of the fore and after conveying carriers ( 1 ) are in contact with each other to engage the movable connector to the connected part ( 33 A) as a connecting mate, and the connection release means ( 11 ) switches the movable connector ( 33 B) at the connecting position to the connection releasing position, and returns it to the connecting position after the fore conveying carrier ( 1 ) travels at a high speed and separates from the after conveying carrier ( 1 ). 
   According to a fourth aspect, the carrier type conveying apparatus can be constituted so that the carrier connection means ( 9 ) includes a connected part ( 33 A) provided on either one of the front and rear end parts of each conveying carrier ( 1 ) and a movable connector ( 33 B) provided on the other of the front and rear end parts of each conveying carrier, the movable connector ( 33 B) can be freely switched between a connecting position and a connection releasing position and selectively held at a connecting position and at a connection releasing position by an urging force, the connection engagement means ( 10 ) switches the movable connector ( 33 B) at the connection releasing position to the connecting position and engages it with the connected part ( 33 A) as a connecting mate in a state that end parts of fore and after conveying carriers ( 1 ) are in contact with each other, and the connection release means ( 11 ) switches the movable connector ( 33 B) at the connecting position to the connection releasing position. 
   When the constitution according to the third aspect is employed, as described in a fifth aspect, it is possible that the movable connector ( 33 B) is provided with a cam follower part ( 39 ), and the connection engagement means ( 10 ) and the connection release means ( 11 ) have cam rails ( 43 ) which act on the cam follower part ( 39 ) and switch the position of the movable connector ( 33 B) according to the traveling of the conveying carriers ( 1 ). This constitution is also applicable when the constitution according to the fourth aspect is carried out. 
   Furthermore, in the case of a carrier type conveying apparatus in which on the conveying carrier ( 1 ), a carriage ( 13 ) supported while enabled to freely elevate by cross link mechanisms ( 12 ) is provided, and in the rear-pushing traveling district ( 3 ), carriage pushing-up rails ( 32 ) which push up the carriage ( 13 ) via the cross link mechanisms ( 12 ) are arranged, as described in a sixth aspect, the connected part ( 33 A) is constituted of an upward hook member ( 34 ), and the movable connector ( 33 B) is pivotally supported so as to freely move up and down between the connecting position at the lower limit and the connection releasing position at the upper limit, and is provided with, on its free end side, an engagement part ( 38 ) engaging downward with the connected part ( 33 A) and a cam follower roller ( 39 ), and the connection engagement means ( 10 ) and the connection release means ( 11 ) include cam rails ( 43 ,  48  and  49 ) which act on the cam follower roller ( 39 ) and switch the position of the movable connector ( 33 B) according to the traveling of the conveying carriers ( 1 ), and in the rear-pushing traveling district ( 3 ), a carrier floating preventive rail ( 44 ) which acts on the cam follower roller ( 39 ) of the movable connector ( 33 B) to press the movable connector ( 33 B) to the connecting position at the lower limit can be disposed. This constitution can also be carried out by being combined with the constitution of the third or fourth aspect. 
   According to a conveying carrier connection system in the carrier type conveying apparatus according to the first aspect of the invention, in the rear-pushing traveling district, as in the case of a conventional one of this sort of carrier type conveying apparatus, rear-pushing drive is possible in a state that end parts of fore and after conveying carriers are in contact with each other, so that in this rear-pushing traveling district, a continuous work floor is formed by the conveying carriers, and operations for the objects to be conveyed loaded on the conveying carriers can be performed on the continuous work floor formed by the conveying carriers, and even if the rear-pushing drive means provided at the inlet of the rear-pushing traveling district malfunctions and it becomes impossible to push the conveying carriers from the rear side in the rear-pushing traveling district, the carrier connection system connects the conveying carriers in this rear-pushing traveling district to each other so as to prevent fore and after conveying carriers from separating a specified distance or longer from each other, so that by the leading conveying carrier which is sent into the high-speed traveling district on the lower route by the speed control drive means on the outlet side of this rear-pushing traveling district, all conveying carriers in the rear-pushing traveling district can be reliably sent to the high-speed traveling district on the lower route. Therefore, at least operations for objects to be conveyed on the conveying carriers in the rear-pushing traveling district and sending out of objects to be conveyed the operations for which have been finished can be reliably continued without stop, and its influence on the work schedule can be minimized. 
   In addition, in the high-speed traveling district in which the conveying carriers sent out from the rear-pushing traveling district are made to travel at a high speed, even when the fore and after conveying carriers approach each other, the fore and after conveying carriers are not connected by the carrier connection system, so that even if an emergency situation occurs in which the means for driving the conveying carriers at a high speed in the high-speed traveling district malfunctions and one conveying carrier stops in the middle of the high-speed traveling district, there is no possibility that following conveying carriers approach and are connected one after another to the stopping conveying carrier by the carrier connection system, and therefore, when restarting after recovery of the malfunction, the conveying carriers can be made to travel at a high speed one by one without fail as in the case of the conventional carrier type conveying apparatus having no carrier connection system, and there is no harmful influence on, for example, sending of the conveying carriers one by one into the rear-pushing traveling district on the lower route. 
   The conveying carrier connection system in the carrier type conveying apparatus according to the invention described above can be easily carried out by the carrier type conveying apparatus according to the second aspect of the invention, however, when carrying out the carrier type conveying apparatus of the invention, according to the constitution of the third aspect, the movable connector constituting the carrier connection means is held at the connecting position by an urging force, so that it becomes simpler in structure and is more easily carried out than in the case where it is selectively held at the connecting position and the connection releasing position. To the contrary, according to the constitution of the fourth aspect, when the conveying carriers travel in the high-speed traveling district, the movable connector is held at the connection releasing position, so that as in the case where the movable connector is held at the connecting position, when an emergency situation occurs in which the conveying carriers approach each other, the fore and after conveying carriers do not collide with each other via the movable connector at the connecting position and the connected part, and can be made to collide at end parts of the conveying carriers, so that damage to the carrier connection means can be avoided. 
   According to the constitution of the fifth aspect, the connection engagement means and the connection release means necessary at the inlet and outlet of the rear-pushing traveling district can be simply constituted by cam rails. 
   In the case of a carrier type conveying apparatus in which the conveying carrier is provided with a carriage supported while enabled to freely elevate by the cross link mechanisms, and in the rear-pushing traveling district, carriage pushing-up cam rails which push up the carriage via the cross link mechanisms are provided, when the carriage is overloaded, although the carriage should be pushed up by the carriage pushing-up cam rails via the cross link mechanisms, there is a possibility that an emergency situation involving floating of the whole of the conveying carrier occurs. To avoid this problem, a carriage floating preventive rail is provided to cover the wheels of the conveying carriers and exclusively provided rollers, however, in the former method, the wheels must be projected lower than the bottom surface of the carrier, and a low-floor conveying carrier realizing excellent workability cannot be obtained, and in the latter method, rollers exclusive for preventing carrier floating are needed, and an increase in cost is inevitable. However, according to the constitution of the sixth aspect, only by adding a carrier floating preventive rail, the carrier floating when the carrier is pushed up in an overloaded state can be prevented by using the cam follower roller of the movable connector for the connection system. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic plan view showing an entirety of a carrier type conveying apparatus; 
       FIG. 2A  is a partially longitudinal sectional view showing an example of conveying carriers, and 
       FIG. 2B  is a plan view of the same conveying carrier; 
       FIG. 3  is a partially cut-away side view showing an elevating mechanism of a carriage provided on the conveying carrier; 
       FIG. 4A  is a partially cut-away side view showing carrier connection means when conveying carriers approach each other in a high-speed traveling district, 
       FIG. 4B  is a partially cut-away side view showing carrier connection means when pulling the following conveying carriers in the rear-pushing traveling district; 
       FIG. 5  is a plan view showing carrier connection means and a part of a cam rail which switches a movable connector of the carrier connection means to a connection releasing position; 
       FIG. 6A  is a side view showing the movable connector and a part of the cam rail which switches the movable connector to the connection releasing position, and 
       FIG. 6B  is a partially cut-away side view showing the movable connector switched to the connection releasing position and a connected part with which the movable connector engages; 
       FIG. 7A  is a side view of a main portion in a state that an elevating carriage of the conveying carrier is pushed up and a cam follower roller of the movable connector acts on a carrier floating preventive rail, and 
       FIG. 7B  is a back view of the main portion showing the cam follower roller of the movable connector and the carrier floating preventive rail; 
       FIG. 8  is a partially longitudinal sectional view showing a cam rail of a connection engagement means in another embodiment and movable connectors on fore and after positions of the cam rail; and 
       FIG. 9  is a partially longitudinal sectional view showing a cam rail of a connection engagement means in another embodiment of  FIG. 8  and movable connectors on fore and after positions of the cam rail. 
   

   DESCRIPTION OF THE SYMBOLS 
   
       
         1 : conveying carrier 
         2 : guide rail 
         3 : rear-pushing traveling district 
         4 : high-speed traveling district 
         5 A: rear-pushing drive means 
         5 B: speed control drive means 
         5 C: high-speed drive means 
         5 D: variable speed drive means 
         6 : friction drive wheel 
         7 : backup roller 
         9 : carrier connection means 
         10 : connection engagement means 
         11 : connection release means 
         12 : cross link mechanism 
         13 : carriage 
         15   a  to  16   b : wheel unit 
         18   a ,  18   b : cross link 
         19 : pushing-up operated means 
         33 A: connected part 
         33 B: movable connector 
         34 : hook member 
         37 : up/down arm 
         38 : engagement part 
         39 : cam follower roller 
         41 : tension coil spring 
         43 ,  48 ,  49 : cam rail 
         44 : carrier floating preventive rail 
         45 : urging means 
         46 : cam plate 
         47 : leaf spring 
     
  
   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, a detailed embodiment of the invention will be described based on the accompanying drawings. In  FIG. 1 , the reference numerals  1  denote conveying carriers which travel on a cyclic traveling route including a pair of left and right guide rails  2 . This cyclic traveling route is formed by connecting a rear-pushing traveling district  3  and a high-speed traveling district  4  which are straight and parallel to each other by U-turn paths, and in the drawings, only inlet and outlet regions of the rear-pushing traveling district  3  are shown and the remaining route is omitted. In the rear-pushing traveling district  3 , a rear-pushing drive means  5 A which propels the conveying carriers  1  at a constant speed is provided at an inlet of the rear-pushing traveling district, and a speed control drive means  5 B for sending out the conveying carriers  1  at a constant speed is provided at an outlet. In the high-speed traveling district  4 , high-speed drive means  5 C which propel the conveying carriers  1  sent out from the rear-pushing traveling district  3  at a high speed are arranged at intervals equal to or slightly shorter than the entire lengths of the conveying carriers  1 , and at the terminal end thereof on the rear-pushing traveling district  3  side, a variable speed drive means  5 D which reduces the speed of the conveying carriers  1  to a traveling speed for the rear-pushing traveling district  3  (conveying carrier drive speed of the rear-pushing drive means  5 A) and sends the conveying carriers into the rear-pushing traveling district  3  is provided. 
   Due to provision of the drive means  5 A through  5 D, in the rear-pushing traveling district  3 , the conveying carriers  1  are in series so that their end parts are in contact with (butted against) each other, and by the tail end conveying carrier  1  driven by the rear-pushing drive means  5 A at the inlet of the rear-pushing traveling district  3 , all conveying carriers  1  in the rear-pushing traveling district  3  are pushed from the rear side and driven at a constant speed. At this time, the speed control drive means  5 B at the outlet of the rear-pushing traveling district  3  is driven with a torque lower than that of the rear-pushing drive means  5 A and at a speed slightly lower than the drive speed of the rear-pushing drive means  5 A, and by braking the leading conveying carrier  1  in the rear-pushing traveling district  3 , the braking speed control drive means  5 B prevents the conveying carriers  1  being pushed from the rear side from traveling at a speed higher than the constant speed due to inertia and gaps arise between the conveying carriers  1 , and sends out the conveying carriers  1  at a constant speed from the rear-pushing traveling district  3 . 
   The conveying carriers  1  sent out from the rear-pushing traveling district  3  into the high-speed traveling district  4  travel by being switched to high-speed driving by the high-speed drive means  5 C, so that in this high-speed traveling district  4 , the conveying carriers  1  travel while maintaining predetermined intervals between fore and after conveying carriers  1 . Then, the conveying carriers  1  reaching the high speed traveling district  1  are reduced in speed to the conveying carrier drive speed of the rear-pushing drive means  5 A by the variable speed drive means  5 D and sent into the rear-pushing traveling district  3 . 
   For each of the drive means  5 A through  5 D, a friction drive means formed by a combination of a friction drive wheel  6  and a backup roller  7  sandwiching the left and right sides of the conveying carrier  1  having a rectangular planar shape long in the traveling direction is used. The reference numeral  8  denotes a motor for driving the friction drive wheel  6 . 
   In the carrier type conveying apparatus described above, according to the invention, a carrier connection system including carrier connection means  9 , a connection engagement means  10  provided on the inlet side of the rear-pushing traveling district  3 , and a connection release means  11  provided on the outlet side of the rear-pushing traveling district  3  is incorporated. Hereinafter, a detailed structure will be described. 
   As shown in  FIG. 2 , on the conveying carrier  1 , a carriage  13  supported so as to be freely elevated by cross link mechanisms  12  is provided, and on the left and right sides of the front and rear sides of this carriage  13 , wheel units  15   a  through  16   b  including wheels  14  which roll on the guide rails  2  are provided. The wheel units  15   a  and  16   a  corresponding to one side of guide rail  2  have a pair of left and right positioning vertical axis rollers  17  which sandwich the guide rail  2  from the left and right sides. The cross link mechanism  12  has, as shown in  FIG. 2  and  FIG. 3 , a pair of left and right cross links  18   a  and  18   b  and a pushing-up operated means  19 . In each of the cross links  18   a  and  18   b , a link  26   a  having one end pivotally supported on the conveying carrier  1  side by a support shaft  20  so as to freely rise and the other end provided with a horizontal axis roller  22  that engages with a horizontal slide guide  21  provided on the bottom of the carriage  13 , and a link  26   b  having one end pivotally supported on the bottom side of the carriage  13  by a support shaft  23  so as to freely rise and the other end provided with a horizontal axis roller  25  that engages with a horizontal slide guide  24  provided on the conveying carrier  1 , are cross-linked by a support shaft  27 , and arbitrary support shafts among the support shafts  20 ,  23 , and  27  and the support shafts of the horizontal axis rollers  22  and  25  may be shared by the cross links  18   a  and  18   b.    
   The pushing-up operated means  19  includes, between the links  26   a  of the cross links  18   a  and  18   b , a horizontal axis roller  28  pivotally supported between the support shafts  20  and  27 , and an elevating member  31  which is supported on the conveying carrier  1  side so as to freely elevate, and has a pushing-up base  29  for pushing-up the horizontal axis roller  28  on its upper end and a cam follower roller  30  pivotally supported on its lower end. In the rear-pushing traveling district  3  to be used as a work line, as shown in  FIG. 3 , carriage pushing-up rails  32  which push up the cam follower roller  30  according to the traveling of the conveying carrier  1  and push up the carriage  13  via the elevating member  31 , the pushing-up base  29 , the horizontal axis roller  28 , and both cross links  18   a  and  18   b  are laid. 
   The carrier connection means  9  include, as shown in  FIG. 2 , a connected part  33 A provided on the front end side of the conveying carrier  1  and a movable connector  33 B provided on the rear end side of the conveying carrier  1 . As shown in  FIG. 4  and  FIG. 5 , the connected part  33 A includes a hook member  34  that is formed of a vertical plate member attached to the front end lower side of the conveying carrier  1  so as to extend forward and has a tip end in an upward hook shape. A front end face  34   b  of a tip end raised portion forming an upward open concave portion  34   a  of the hook member  34  is formed to be vertical. 
   The movable connector  33 B of the carrier connection means  9  includes a pair of left and right arms  37  freely movable up and down which are pivotally supported on a bearing member  35  projectedly provided on the lower side near the rear end of the conveying carrier  1  by a horizontal support shaft  36  set transverse, and extend rearward, and an engagement part  38  formed of a horizontal shaft laid across the tip end parts (rear end parts) of the arms  37 , and the horizontal shaft forming this engagement part  38  is extended to one side and on its free end, a cam follower roller  39  is supported, and by a tension coil spring  41  tensioned and provided between a spring latching member  40  fixed to a portion extending from the support shaft  36  of the arms  37  to the opposite side (forward) and the conveying carrier  1 , the movable connector  33 B is held in an urged state to a connecting position at the lower limit where the spring latching member  40  comes into contact with a stopper  42  provided on the bearing member  35 . Instead of the tension coil spring  41 , a twist coil spring which freely fits with the support shaft  36  may be used, or it is also possible that the movable connector  33 B is held in an urged state to the connecting position at the lower limit by gravity by providing a sufficient weight on the engagement part  38  side. 
   The movable connector  33 B constructed as described above is provided so that the engagement part  38  is positioned on an imaginary straight line in the fore and after direction passing through the connected part  33 A (hook member  34 ), and in the movable connector  33 B held in an urged state to the connecting position at the lower limit by the spring  41 , as shown in  FIG. 4A , the engagement part  38  is positioned at the same level as or slightly lower than the central axis level of the support shaft  36  and when the engagement part  38  is pushed horizontally rearward by the front end vertical face  34   b  of the hook member  34  as the connected part  33 A of the after conveying carrier  1 , this movable connector  33 B does not move upward against the urging force of the spring  41 . In this movable connector  33 B, as shown in  FIG. 4B , when the fore and after conveying carriers  1  are adjacent to each other in a state that their end parts are in contact with each other, the engagement part  38  can be engaged downward in a concave portion  34   a  of the hook member  34  as the connected part  33 A of the after conveying carrier  1 . 
   The connection engagement means  10  and the connection release means  11  shown in  FIG. 1  are formed by, as shown in  FIG. 5  and  FIG. 6 , cam rails  43  which act on the cam follower roller  39  of the movable connector  33 B, and move up the movable connector  33 B against the urging force of the spring  41  according to the traveling of the conveying carriers  1 , and switch the movable connector  33 B to a connection releasing position at which the engagement part  38  is slightly higher than the upper end level of the front end raised portion of the hook member  34  as the connected part  33 A. As shown by the imaginary line of  FIG. 1  and in  FIG. 7 , in the rear-pushing traveling district  3 , a carrier floating preventive rail  44  can be provided which covers the cam follower roller  39  of the movable connector  33 B to prevent the movable connector  33 B from moving up against the urging force of the spring  41  while leaving an appropriate space from the cam rails  43  forming the connection engagement means  10  and the connection release means  11  provided at the inlet and the outlet of the district. 
   In the constitution described above, the lengths and positions of the cam rails  43  forming the connection engagement means  10  and the connection release means  11  are set so that the following action is reliably performed. That is, as described above, at the inlet of the rear-pushing traveling district  3 , conveying carriers  1  are successively sent into the rear-pushing traveling district  3  from the high-speed traveling district  4  on the higher route, and in this process, the vicinity of the inlet of the rear-pushing traveling district  3  includes a region in which the after conveying carrier  1  comes up to the fore conveying carrier and their end parts are adjacent to each other. The cam rail  43  of the connection engagement means  10  is provided to cover this region. 
   Therefore, at the inlet of the rear-pushing traveling district  3 , as shown in  FIG. 6B , in a state that the movable connector  33 B of the fore conveying carrier  1  is switched to the connection releasing position via the cam rail  43  and the cam follower roller  39 , the after conveying carrier  1  approaches this fore conveying carrier  1 , so that as shown in  FIG. 4A , the movable connector  33 B at the connecting position of the fore conveying carrier  1  and the hook member  34  as the connected part of the after conveying carrier  1  are not brought into contact with each other, and the front end of the after conveying carrier  1  comes into contact with the rear end of the fore conveying carrier  1 . In this state, the fore and after conveying carriers  1  advance more and then the cam follower roller  39  of the movable connector  33 B is disengaged from the cam rail  43 , the movable connector  33 B moves downward due to the urging force of the spring  41  to return to the connecting position, and as shown in  FIG. 4B , the engagement part  38  of the movable connector  33 B of the fore conveying carrier  1  engages downward in the concave portion  34   a  of the hook member  34  as the connected part of the after conveying carrier  1 , whereby these fore and after conveying carriers  1  are connected to each other. The fore and after conveying carriers  1  in this connected state are allowed to come into contact at their end parts with each other, but are prevented from being separated a specified distance or longer in the fore and after direction by the contact between the engagement part  38  of the movable connector  33 B and the front end raised portion of the hook member  34  as shown in  FIG. 4B . 
   In other words, all conveying carriers  1  within the rear-pushing traveling district  3  in which the conveying carriers  1  are driven by being pushed from the rear side by the tail end conveying carrier  1  that is driven at a constant speed by the rear-pushing drive means  5 A travel at a constant speed in a desired state in that their end parts are in contact with each other, and the connected part  33 A and the movable connector  33 B of the carrier connection means  9  do not apply loads to each other although they engage with each other, so that the fore conveying carrier  1  is not pulling the after conveying carrier  1 . However, if the rear-pushing drive means  5 A malfunctions and rear-pushing driving for the tail end conveying carrier  1  to be sent from the high-speed traveling district  4  is not performed, all conveying carriers  1  in the rear-pushing traveling district  3  after the leading conveying carrier  1  to be sent out from the rear-pushing traveling district  3  by the speed control drive means  5 B at the outlet of the rear-pushing traveling district  3  are successively pulled by the fore conveying carriers  1  due to engagement between the movable connectors  33 B of the fore conveying carriers  1  and the connected parts  33 A (hook member  34 ) of the after conveying carriers  1 , and sent out into the high-speed traveling district  4  on the lower route by the speed control drive means  5 B without staying in the rear-pushing traveling district  3 . 
   Before the leading conveying carrier  1  to be sent out from the rear-pushing traveling district  3  according to the rear-pushing action of the after conveying carrier  1  or the constant speed sending action of the speed control drive means  5 B in the above-described emergency situation, the cam rail  43  of the connection release means  11  moves up the movable connector  33 B at the connecting position of this leading conveying carrier  1  against the urging force of the spring  41  via the cam follower roller  39 , and as shown in  FIG. 6B , switches the movable connector  33 B to the connection releasing position at which the engagement part  38  comes out upward from the inside of the concave portion  34   a  of the hook member  34  as the connected part  33 A of the after conveying carrier  1 . In this state, simultaneously when or after the leading conveying carrier  1  separates from the speed control drive means  5 B, the leading conveying carrier  1  is pushed from the rear side by the after conveying carrier  1  and reaches a position where it is propelled by the first high-speed drive means  5 C in the high-speed traveling district  4 , whereby the leading conveying carrier  1  separates from the after conveying carrier  1  and travels at a high speed. After the leading conveying carrier  1  is thus driven at a high speed and separated from the after conveying carrier  1 , the movable connector  33 B of this leading conveying carrier  1  separates at its cam follower roller  39  from the cam rail  43  and returns again to the connecting position by the urging force of the spring  41 . 
   Therefore, the movable connector  33 B of each conveying carrier  1  traveling at a high speed in the high-speed traveling district  4  is in a state that it is urged to and held at the connecting position at the lower limit by the urging force of the spring  41 . Therefore, even if one of the high-speed drive means  5 C malfunctions and causes an emergency situation in which the first conveying carrier  1  stops in the middle of the high-speed traveling district  4  and the following conveying carriers  1  approach and collide with the first conveying carrier  1  being stopped, the movable connector  33 B of the fore conveying carrier  1  and the connected part  33 A of the after conveying carrier  1  only comes into contact with each other between the engagement part  38  of the movable connector  33 B and the front end vertical face  34   b  of the front end raised portion of the hook member  34  as shown in  FIG. 4A , and there is no possibility that the engagement part  38  of the movable connector  33 B engages in the concave portion  34   a  of the hook member  34  and the fore and after conveying carriers  1  are connected to each other. Therefore, when the high-speed drive means  5 C which had stopped is recovered and restarted, the conveying carriers  1  which had stopped in series are driven at a high speed independently from each other, so that there is no possibility that a plurality of conveying carriers  1  are driven at a high speed while connected to each other by the carrier connection means  9 . 
   The rear-pushing traveling district  3  is used as a work line as described above. That is, on each conveying traveling body  1  that has entered this rear-pushing traveling district  3 , operations to attach parts to a objects to be conveyed (for example, an automobile body) loaded on the carriage  13  are performed, and at this time, according to the level of a portion to be operated of the objects to be conveyed, the carriage  13  is automatically elevated to a predetermined level via the carriage pushing-up rails  32  and the cross link mechanisms  12 . That is, when the conveying carrier  1  enters a district in which the carriage pushing-up rails  32  are laid within the rear-pushing traveling district  3 , the carriage pushing-up rails  32  raise the cross links  18   a  and  18   b  of the cross link mechanisms  12  via the pushing-up operated means  19  to elevate the carriage  13  to a predetermined level, and at this time, if the carriage  13  is overloaded (over loading capacity), when the carriage pushing-up rails  32  attempt to raise the cross links  18   a  and  18   b , the cross links  18   a  and  18   b  do not rise and the conveying carriage  1  itself is pushed up and may float from the guide rails  2 . However, in this embodiment, the conveying carrier  1  which has entered the rear-pushing traveling district  3  and whose movable connector  33 B has been separated from the cam rail  43  of the connection engagement means  10  travels to the outlet of the rear-pushing traveling district  3  in a state that the carrier floating preventive rail  44  covers the cam follower roller  39  of this movable connector  33 B to prevent an upward movement of the movable connector  33 B that has returned to the connecting position at the lower limit, so that when the conveying carrier  1  itself is about to float due to a reaction force of the pushing-up operation for the carriage  13 , the cam follower roller  39  of the movable connector  33 B at the lower limit position comes into contact with the lower side surface of the carrier floating preventive rail  44  and prevents floating of the conveying carrier  1 . 
   In the embodiment described above, the movable connector  33 B is held in an urged state to the connecting position at the lower limit by the spring  41 , however, as shown in  FIG. 8 , it is also possible that the movable connector  33 B is pivotally supported by a support shaft  36  so as to freely swing up and down between the connecting position at the lower limit and the connection releasing position at the upper limit, and an urging means  45  which switches and holds this movable connector  33 B selectively between the connecting position at the lower limit and the connection releasing position at the upper limit is provided. This urging means  45  includes, for example, as illustrated, a cam plate  46  provided on a side opposite the side of the engagement part  38  with respect to the support shaft  36  of the movable connector  33 B and a leaf spring  47  which pressure-contacts with the cam plate  46 . The cam plate  46  is provided with a cam surface  46   a  with which the leaf spring  47  pressure-contacts and holds the movable connector  33 B at the connecting position when this movable connector  33 B is at the connecting position at the lower limit, and a cam surface  46   b  with which the leaf spring  47  pressure-contacts to hold the movable connector  33 B at the connection releasing position when this movable connector  33 B is at the connection releasing position at the upper limit. Thus, the central position between the connecting position at the lower limit and the connection releasing position at the upper limit becomes a dead point of the movable connector  33 B, and by moving up or down the movable connector  33 B against the urging force of the leaf spring  47  to a position over this dead point, it automatically moves to the opposite position due to the urging force of the leaf spring  47  and is held there. 
   When using the carrier connection means  9  including the movable connector  33 B constituted as described above, as the connection engagement means  10  provided at the inlet of the rear-pushing traveling district  3 , as shown in  FIG. 8 , the cam rail  48  which forcibly moves the movable connector  33 B held at the connection releasing position to a position over the dead point toward the connecting position side via the cam follower roller  39  is provided, and as the connection release means  11  provided at the outlet of the rear-pushing traveling district  3 , as shown in  FIG. 9 , the cam rail  49  which forcibly moves the movable connector  33 B held at the connecting position to a position over the dead point toward the connection releasing position via the cam follower roller  39  is provided. 
   Therefore, the movable connectors  33 B of the respective conveying carriers traveling at a high speed in the high-speed traveling district  4  are urged to and held at the connection releasing position differently from the aforementioned embodiment, so that even if a certain conveying carrier  1  makes an emergency stop, conveying carriers  1  after this carrier stop in a state that their front ends are in contact with the rear ends of the fore conveying carriers  1  independently from the carrier connection means  9 , there is no possibility that the conveying carriers apply loads to the carrier connection means  9 . 
   INDUSTRIAL APPLICABILITY 
   The conveying carrier connection system in the carrier type conveying apparatus of the invention is constructed so that an automobile body (object to be conveyed) to which various parts will be attached is loaded on the carriage and conveyed so that an operator who gets on the conveying carrier  1  in a part assembly operation district (rear-pushing traveling district described in the embodiment)  3  performs operations to attach parts to the automobile body, and this is applicable to an automobile assembly line.