US3724391A

US3724391A - Overhead conveyor

Info

Publication number: US3724391A
Application number: US1*7A
Authority: US
Inventors: Velde H Te
Original assignee: US Philips Corp
Current assignee: US Philips Corp
Priority date: 1970-01-27
Filing date: 1971-01-05
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: DE2100570A1; AT317768B; JPS548950B1; GB1346243A; DE2100570B2; ZA708426B; ES387578A1; CA938577A; SE375490B; DE2100570C3; BE762018A; NL165430B; NL7001084A; CH539566A; NL165430C; FR2077363A1; FR2077363B1

Abstract

A conveyor having a main track and a local lower track and having double trolleys each being formed of a driving crab and a suspension crab. The suspension crab is detachably coupled to the driving crab by means of a self-centering ball and socket type coupling. In the coupled condition the suspension crab is locked against undesired uncoupling by safety means formed of a locking pawl pivotally arranged to engage various cam surfaces of the crabs in order to prevent undesired uncoupling.

Description

- United States Patent 1 91 Velde [4 1 Apr. 3, 1973 [54] OVERHEAD CONVEYOR 2,894,460 7/1959 Klamp ..104/83 Inventor: Harm Frank Te Velde, Eindhoven, 3,180,279 4/1965 Thlbault ..l04l89 Ne't'hcrlands Primary Examiner-Gerald M. Forlenza [73] Assxgnee: U.S. hi ip p n, New Assistant Examiner-Robert Saifer York, N.Y. Attorney-Eran]: R. Trifari [22] Filed: Jan. 5, 1971 [2]] Appl. No.: 104,069 [57] ABSTRACT A conveyor having a main track and a local lower [30] Foreign Application Priority Data track and having double trolleys each being formed of a driving crab and a suspension crab. The suspension Jan. 27, 1970 Netherlands ..7001084 crab is detachably coupled to the driving crab y [52] U 8 Cl 104/172 8 104/88 104/89 means of a self-centering ball and socket type 198/l77 coupling. In the coupled condition the suspension crab 51 [111. CI 865g 17/42 is against undesired uncmlpling by Safety 58 Field of Search ..104/88 89 90 91 96 97 means firmed mung Pivmlly arranged 104/172 S 173 178 lO'5/148 1 engage various cam surfaces of the crabs in order to 151, 156; 168/177 R; 16/88; 24/324 prevent undesired uncoupling.

[ References Cited 16 Claims, 22 Drawing Figures UNITED STATES PATENTS 2,632,402 3/1953 Reussner ..104 173 PATENTEDAPR 3 I975 SHEET UlUF 11 IZ\"\ EN'1'OR.

HARM F. TE VELDE PATENTEDAPRB 975 3,724,391

sum OZUF 11 Fig.2a

INVENTOR.

HARM F. TE VELDE w A FNT PATENTEU N I375 3,724,391

SHEET O3UF 11 Fig.2b

[NVENTOR HARM F. TE VELDE A 1 k :M;

AGE T PATENTEUAPR3 I975 SHEET 0 4 []F 11 Fig.3a

INVEN'I'OR.

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'ZYMWM AGENT PATENTEDAPRB I975 3.724.391

SHEET UBUF 11 Fig.4a

INVENTOR.

HARM F. TE VELDE m LWQ L- ANT PATENTEDAFM 1975 SHEET 07 0F 11 INVEN TOR HARM F. TE VELDE PATENTEDAPR 3 I975 SHEET U80F 11 INVENTOR.

HARM F. TE VELDE PATENTEDAPR 3 I975 SHEET USUF 11 ENT PATH-HEB APR 3 1975 SHEET lUUF 11 PATENTEUAFR 3 I975 SHEET llflF 11 INVENTOR.

HARM E TE VELDE AGE T OVERHEAD CONVEYOR The invention relates to an overhead conveyor having an endless transporting chain and a closed single guide track which together form a main track. At least one local lower track forming a side track is provided. Trolleys are provided, each consisting mainly of a driving crab and a suspension crab, the driving crab travels in the guide track and may be driven by the transporting chain and the suspension crab can be coupled to the driving crab by means of a detachable connection. The conveyor also has means for automatically coupling and uncoupling the suspension crabs and switches for transferring the suspension crabs from one track to the other track.

Such a conveyor is already known. In this known device the detachable connection consists of two hooks which are directed at right angles to each other. The suspension crab is not safeguarded against a nondesired and nonautomatic uncoupling, for example, as a result of irregularities during conveying. Moreover, the said apparatus suffers from the drawback that the suspension crab can slide in an undesirable manner relative to the driving crab, can rock about a horizontal axis, and can rotate about a vertical axis.

It is the object of the invention to provide a conveyor which does not exhibit these drawbacks, in which the suspension crab is prevented from undesirable and non-automatic uncoupling in all circumstances and always assumes an accurately determined position relative to the driving crab.

The foregoing object is achieved by providing a detachable connection which has a self-centering coupling and safety means, the connection being adapted to be locked and unlocked automatically.

As a result of the self-centering coupling, the suspension crab is accurately and automatically fixed relative to the driving crab; relative movements of the suspension crab and the driving crab are prevented in the coupled condition of the coupling. Due to the safety means and the automatic locking and unlocking of the connection, undesirable and non-automatic uncoupling of the suspension crab, other than in the switches, is not possible.

According to a preferred embodiment of the conveyor according to the invention, the coupling consists of two cooperating spherical coupling members which are provided on two curved claws of the driving crab and the suspension crab, which claws face each other and overlap each other, the safety means comprising a locking pawl on one claw and a locking cam and a guide face on the other claw.

Due to the spherical coupling members, the suspension crab is capable of preforming all the necessary and desirable rotary movements relative to the driving crab, in particular when the trolley travels along an incline. Coupling and uncouplingcan take place in a simple manner by a controlled movement of the suspension crab in a vertical direction. As a result of the claws which are curved and face each other, sufficient space is available for said vertical movement. Rotary movement of the suspension crab in the uncoupled lifted condition about a perpendicular axis for transferring the suspension crab between the main track and the side track is thus possible. The locking pawl cooperating with the locking cam prevents the undesired uncoupling of the suspension crab in one horizontal direction, the claw of the driving crab preventing uncoupling in the opposite direction.

A preferred embodiment of the conveyor according to the invention is characterized by cooperating stop surfaces on the two claws and on the locking pawl. As a result of the stop surfaces contacting each other, displacements and rotary movements of the suspension crab relative to he driving crab are restricted.

According to a further preferred embodiment of the conveying apparatus according to the invention, the claw of the driving crab is situated partly in the guide track, the free space between the guide track and the spherical coupling member of said claw being smaller than the lifting stroke of the other coupling member necessary for uncoupling.

Due to the featured arrangement of the claw of the driving crab relative to the guide track, the claw of the suspension crab in the uncoupled lifted condition becomes located partly between the guide track; the guide track prevents undesired lateral displacement and uncoupling, if any, of the suspension crab.

As already explained, a rotary movement of the suspension crab in the uncoupled lifted condition and about a vertical axis is possible. During conveying, however, such a rotary movement of the suspension crab is usually not desired. In the coupled condition of the coupling, a rotary movement of the suspension crab about a vertical axis and about a horizontal axis parallel to the conveying apparatus is restricted, if necessary, by the coupling members being formed by a ball portion on the end of one one-armed claw and by a socket portion on the other two-armed claw. The arms of the two-armed claw, in cooperation with the one-armed claw, forms a guide for the suspension crab. The onearmed claw may be provided on the driving crab and the ball portion points in the direction of conveying, the two-armed claw forming part of the suspension crab and having its socket portion remote from the direction of conveying. The locking pawl may be arranged on the one-armed claw so as to be rotatable and the locking cam with the guide face may be arranged on the two-armed claw.

As a result of this construction it is possible to arrange the locking cam and the guide face on the upper side of the socket portion which has a proportionally large area. In the coupled condition, the locking pawl bears on the guide face of the two-armed claw under the influence of gravity, and thus assumes a favorable position for a succeeding renewed coupling. In cooperation with the locking cam, the locking pawl prevents the uncoupling of the suspension crab in the direction of conveying and in the uncoupled condition of the coupling. Further, the two claws constitute cooperating stop members in the case of any relative movement of the crabs in the opposite direction. In the uncoupled condition of the coupling, the two-arms claw with the socket portion is enclosed between the locking pawl, the one-armed claw and the guide track.

As already described above, the suspension crab in the coupled condition is prevented from undesirable movements, both in the lateral direction and in the two longitudinal directions, and, if necessary, against rotary movements about a perpendicular axis and about a horizontal axis parallel to the direction of conveying. However, rotary movements of the suspension crab relative to the driving crab about a horizontal axis perpendicular to the direction of conveying must be possible in order to be able to move along inclines during conveying. This can be accomplished by having the locking pawl comprise a spherical supporting surface the width of which is smaller than the free spacing between the arms of the two-armed claw, a locking projection and a recess between the supporting surface and the locking projection.

The recess between the supporting surface and the locking projection of the locking pawl receives the locking cam, as a result of which rotary movements of the crab about a horizontal axis perpendicular to the conveying apparatus and in both directions are possible without the function of the locking pawl being removed.

For transferring the suspension crabs from the main track to the side track and from the latter back to the main track, the switches may be operated manually. Preferably, however, the suspension crab comprises a coding beam with coding elements for the automatic control of the switches.

The invention may be used, both in setting up new conveyors and in reconstructing existing conveyors. In both cases trolleys having the characteristic features according to the invention are used, each mainly consisting of a driving crab and a suspension crab, in which the suspension crab can be coupled to the driving crab by means of a detachable connection and in which, according to the invention, the detachable connection consists of a self-centering coupling and of safety means in which the connection can be automatically locked and unlocked.

In order that the invention may be readily carried into effect, one embodiment thereof will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

FIG. 1a shows a conveying diagram having a main track and a local lower track,

FIG. 1b diagrammatically shows the variation in height of the lower track,

FIG. 2a and 2b are a side view and a front elevation of a part of the main track of the conveyor according to the invention having a double trolley;

FIGS. 3a and 3b show the trolley during raising and lowering in the main track with an incline of 45,

FIGS. 4a and 4b are a side view and a front elevation of the main track and of the local lower track with a trolley,

FIGS. 5a to 5d are sides view of the driving crab and the suspension crab in various positions during uncoupling,

FIGS. 6a to 6c are plan views of the driving crab and the suspension crab during transferring the suspension crab from the main track to the side track,

FIGS. 7a to 7c are plan views of the driving crab and the suspension crab during transferring the suspension crab from the side track back to the main track,

FIGS. 80 to 8d are side views of the driving crab and the suspension crab during coupling.

FIG. la is a part of a conveying diagram showing a main track 1 and a local lower track 3 which on the part A-C forms a double track with the main track 1 and the part C-D of which is constructed as an uncoupling switch; the part D-E-F of the lower track 3 constitutes a loop-shaped side track 5 which, via a coupling switch F-G, again changes into a double track G-K.

FIGS. 2a and 2b are a side view and a cross-sectional view, respectively, of a part of the main track 1, which is composed of an endless transporting chain 6 and of a hollow closed guide track 9 mainly formed by four profile irons 7. The main track 1 serves to displace and guide double trolleys 11 one of which is shown in FIGS. 2 to 8. Each trolley 11 is mainly composed of a driving crab l3 and a suspension crab 15 which is detachably coupled to the driving crab by means of a self-centering coupling 16. The driving crab 13 is driven by transporting chain 6 travelling in the guide track 1; the profile irons 7 of the hollow guide track 9 in cooperation with the supporting rollers 17 and the guide rollers 19 of the driving crab l3 constitute a guide for the trolley 1 1. For transferring the suspension crab 15 from the main track 1 to the side track 5, the suspension crab 15 may be uncoupled from the driving crab 13; during transferring of the suspension crab 15 from the side track 5 to the main track 1, the suspension crab 15 is again automatically coupled to the driving crabs l3 and in the coupled condition is absolutely prevented from any undesirable uncoupling.

For that purpose, the driving crab 13 comprises a curved one-armed claw 23 which is secured to links 21 between cross-pieces 22 of the transporting chain 6 and which extends between the lower profile irons 7 downwards and in the direction of conveying denoted by an arrow x. The suspension crab 15 also comprises a curved claw 25 the free end of which, however, comprises two arms 27. This two-armed claw 25 extends in a direction opposite to the direction of conveying x, in such manner that the two

claws

23 and 25 face each other and overlap each other. A spherical coupling member which is formed of a ball portion 29 on the free end of said claw is provided on the one-armed claw 23. The two-armed claw 25 is provided with a corresponding spherical coupling member which is formed of a socket portion 31 on the lower side of said' claw, the upper side 32 of which is flat. The claw 25 can be uncoupled by lifting the suspension crab 15. For coupling, the suspension crab 15 is moved lowered, the socket portion 31 being automatically fixed relative to the ball portion 29. In the coupled condition, the onearmed claw 23 becomes situated partly between the arms 27 of the two-armed claw 25. The free distance a between the lower side of the guide track 9 and the ball portion 29 is smaller thanthe lifting stroke of the claw 25. On the side of the driving crab l3 remote from the one-armed claw 23, a locking pawl 23 is rotatably journalled on a shaft 34 in such manner that the free end thereof extends in the direction of the coupling 16. The locking pawl 33 comprises a spherical supporting surface 35, a locking projection 37, a recess 39 between the supporting surface and the locking projection, and on either side, a stop surface 40. The width of the supporting surface 35 and of the locking projection 37 is smaller than the free distance b between'the arms 27 of the claw 25. The socket portion 31 of the claw 25 comprises on its flat upper side 32 a locking cam 41 and a guide surface 43 which extends partly'horizontally and partly at an angle. The cam and surface can cooperate with the locking projection 37 of the locking pawl 33.

The suspension crab comprises supporting rollers 45 and guide rollers 47, a coding beam 49 with slidable coding pawls 51, a protection plate 53 and a pivotable suspended hook 55 to which a product to be conveyed or a frame receiving a product can be secured.

FIGS. 2a and 2b show the trolley 11 with the driving crab 13 in the guide track 9 of the main track 1 during normal conveying, the coupled suspension crab 15 being suspended from the driving crab 13. In this condition the claw 25 bears on the ball portion 29 of the claw 23 with its socket portion 31. The one-armed claw 23 extends partly between the arms 27 of the two armed-claw 25, the locking pawl 33 with the locking projection 37 resting on the guide surface 43. In this condition the suspension crab 15 is fixed accurately relative to the driving crab 13 by the self-centering coupling 16. If, as a result of irregularities during conveying, the suspension crab 15 is lifted, the locking projection 37 is moved along the guide surface 43 in the direction of the locking cam 41, the locking pawl 33 performing a rotary movement about the shaft 34. In extreme cases, the

claws

23 and 25 may assume an uncoupled condition corresponding, for example, to FIG. 50. In spite of this, the suspension crab 15 is absolutely safeguarded against uncoupling. Uncoupling of the suspension crab 15 in the direction of conveying is prevented by the locking pawl 33 and in the opposite direction by the ball portion 29 which forms a stop for the claw 25. Uncoupling of the suspension crab 15 in the lateral direction is also impossible because the distance a between the lower side of the guide track 9 and the ball portion 29 is smaller than the lifting stroke of the claw 25 necessary for uncoupling. The result of this is that the arms 27 of the claw 25 in the lifted condition become situated between the'lower profiled rods 7 of the guide track 9, as a result of which a lateral uncoupling of the suspension crab is prevented.

The suspension crab 15 must be capable of performing rotary movements about a horizontal axis perpendicular to the direction of conveying, so as to be able to move along inclines in the main track 1 in both directions and with an unaltered vertical position of the crab 15. FIGS. 3a and 3b show the trolley 11 during ascending and descending in an incline of 45 of the main track 1. In the position during ascending shown in FIG. 3a, the socket portion 31 is rotated relative to the ball portion 29 in such manner that the locking pawl 33 becomes situated with its spherical supporting surface 35 between the two arms 27 of the claw 25, the supporting surface 35 bearing on the ball portion 29. In the case of a small perpendicular movement of the suspension crab 15 in the direction of the guide track 9, the locking pawl 33 with its stop surfaces 40 engages the upper side 32 of the claw 25 so that a further movement of said claw and the uncoupling of the suspension crab 15 is impossible. The relative rotation of the crabs is restricted by stop surfaces 30 and 44 on the claws which contact each other.

In the position shown in FIG. 3b during descending of the trolley 11, the socket portion 31 is rotated relative to the claw 23 in such manner that the locking pawl 33 bears with the locking projection 37 on the inclined part of the guide surface 43. In the case of a perpendicular movement of the suspension crab 15 in the direction of the guide track 9, the claw 25 with its surface32 contacts the stop surfaces 30 on the claw 23 so that a further movement of the suspension crab 15 is prevented. In this position the rotary movement of the suspension crab 15 is restricted in that it contacts with the inclined surface 48 the cross-piece 22 of the transporting chain 6. g

In every possible coupled condition of the trolley 11 in the main track I, the arms 27 of the claw 25, in cooperation with the one-armed claw 23, constitute a guide as a result of which undesirable rotary movements of the suspension crab 15 about a perpendicular axis, as well as about a horizontal axis parallel to the direction of conveying,,are restricted to the necessary movements.

FIGS. 4a and 4b show the trolley 1 l in a double-track portion of the main track 1, with the driving crab 13 in the guide track 9, and with the suspension c'rab 15 in the local lower track 3 which is constituted by four profile irons 57. The profile irons 7 of the main track 1 and the profile irons 57 of the lower track 3 may have the same dimensions. On this double-track portion of the main track 1 which is denoted by the part A-B in FIGS. la and 1b which extends horizontally, the suspension crab 15 with the supporting rollers 45 contacts the profile irons 57, in which portion, however, the

claws

23 and 25 are still in the coupled condition. Moving the suspension crab 15 in the direction of the guide track 9 for uncoupling the claws is effected by means of the lower track 3. The variation in the direction of height of the lower track 3 is shown in FIG. lb. On the part A-B the lower track 3 extends horizontally. With automatic control of the uncoupling switch C-D, electronic, electro-optic or other automatically operating sensors are provided for sensing the operative coding pawls on the coding beam 49 for the automatic switching of the switch. of course the switch may also be operated manually. On the uncoupling part B C, the lower track 3 extends upwards for uncoupling the

claws

23 and 25. In the uncoupling switch C-D, and in the coupling switch F-G, the suspension crabs 15 are driven by switch wheels N and by pawls M which cooperate with recesses 59 in the protecting plates 53 of the suspension crabs 15, the speeds of the pawls M and of the transporting chain 6 being synchronized. The movement of the suspension crabs 15 in the side track 5 may take place, inter alia, by gravity, the lower track 3 being inclined downwards on the part D-E-F. In the coupling switch F-G, the lower track 3 is also horizontal. 0n the coupling part G-I-l-K, the lower track 3 is inclined upwards on the part G-I-l for raising the suspension crab 15. On the part I-I-K the lower track 3 descends for lowering the suspension crab 15 and for coupling the

claws

23 and 25. I

FIGS. 5a to 5d are side views of various positions of the trolley 11 during uncoupling the claws, the direction of conveying being denoted by the arrow x. The main track 1 is shown only diagrammatically. On the horizontal part A-B of the lower track 3, the claws are coupled together. This position for the point B of the track is shown in FIG. 5a. When the suspension crab 15 moves upwards, which is effected automatically by the rising uncoupling part B-C of the lower track 3 as shown in FIG. 5b, the claw 25 is moved upwards over such a distance that the ball portion 29 is entirely released; figure 5c shows the

claws

23 and 25 in the uncoupled condition at the entrance C of the uncoupling switch C-D, the suspension crab being still safeguarded. The suspension crab 15 is pushed by the driving crab 13, the ball portion 29 engaging the inside 42 of the claw 25. Once the suspension crab 15 is removed from the main track 1, the locking pawl 33 will rest on the ball portion 29 with its spherical supporting surface 35; the position of the locking pawl 33 v is such that a renewed coupling and locking of the suspension crab 15 can take place automatically.

FIGS. 6a to 6c are plan views of various positions of the driving crab 13 and the suspension crab 15 during transferring the suspension crab from the main track 1 to the side track 5 after uncoupling the claws. FIG. 6a which corresponds to FIG. 50 shows the

claws

23 and 25 in the uncoupled condition at the entrance C of the uncoupling switch C-D. The uncoupling switch is already in the desired position for transferring the suspension crab 15. By a rotary movement of the suspension crab about a perpendicular axis and in the uncoupling switch, the suspension crab is removed from the main track land follows the lower track 3 which changes into the side track 5, while the driving crab ,13 remains following the main track 1. FIGS. 6b and 60 show relative positions of the driving crab 13 and of the suspension crab 15 during uncoupling and transfer of the suspension crab 15. I

FIGS. 7a to 70 show a few positions of the driving crab 13- and of the suspension crab 15 during the transfer thereof from the side track 5 back to the main track 1. FIG. 7a shows the positions of the driving crab l3 and of the suspension crab 15 before the exit G of the horizontally extending coupling switch F-G. At point G of the switch suspension crab 15 is transferred in the main track 1 by the synchronized drive of the pawls M in such manner that the claw 23 engages the arms 27 of the claw 25 with its ball portion 29. In this position, which is shown in FIG. 7b, the suspension crab I5 is pushed by the driving crab 13. FIG. 8b is a side elevation of the driving crab l3 and the suspension crab 15 in a position corresponding to FIG. 7b. On the adjoining ascending part G-I-I of the lower track 3 the suspension crab 15 is moved upwards, during which the ball portion 29 can slide along the bevelled lower sides of the arms 27 of the claw 25 and engages the inner edge 42 of said claw. FIGS. 70 and 8c show the

claws

23 and 25 on the ascending part G-I-I in a position in which they are not yet coupled, the suspension crab being already safeguarded from undesirable coupling.

Adjoining the ascending action of the suspension crab 15, it is again lowered on the descending part I-I-K of the lower track 3. FIG. 8d shows the

claws

23 and 25 on the descending part I-l-K during coupling.

As already described in detail, the suspension crab is absolutely safeguarded by the locking pawl 33 in every possible coupled condition of the claws both on the horizontal and on the ascending and descending parts. In the uncoupled conditions of the claws in the doubletrack of the main track, before the uncoupling switch and behind the coupling switch, the uncoupling of the suspension crab both in the two longitudinal directions and in the lateral direction is also impossible. Moreover, the suspension crab 15 in the double-track part is guided in the lower track 3.

By the self-centering action of the coupling the suspension crab 15 is automatically and accurately placed relative to the driving crab 13, a proportionally large relative rotary movement of the driving crab l3 and the suspension crab 15 about a horizontal axis perpendicular to the direction of conveying in both directions being possible. The locking of the suspension crab is effected automatically and in a simple manner by the locking pawl 33, by the

claws

23, 25 and by the various stop surfaces; undesirable uncoupling other than in the switches is not possible. If intentional manual unlocking is desired, it is necessary only to lift the locking pawl 33 and to remove the suspension crab 15 with the claw 25 from the driving crab 13.

The invention has been described with referenceto an embodiment having a single trolley. Of course, all the trolleys of the conveying apparatus are coupled and uncoupled in the manner described, it being possible to combine any suspension crab with any driving crab.

The embodiment described and shown in the drawing is a preferred embodiment of the conveyor according to the invention. The invention also comprises embodiments in which the shape and the relative arrangement of the claws, of the spherical coupling members, and of the locking pawl deviate from the embodiment.

What is claimed is:

1. An overhead conveyor having an endless transporting chain and a closed single guide track which together form a main track, at least one local lower track forming a side track, a plurality of trolleys each comprising a driving crab and a suspension crab, said driving crab travelling in the guide track so as to be driven by the transporting chain, a detachable connection for coupling the suspension crab to the driving crab, means for automatically coupling and uncoupling the suspension crabs, switches for transferring the suspension crabs from one track to the other track, said detachable connection comprising a self-centering coupling and safety means, the connection being adapted to be locked and unlocked automatically, said coupling comprising two cooperating spherical coupling members which are provided on curved claws one of which is provided on the driving crab and the other of which is provided on the suspension crab, which claws face each other and overlap each other, the safety means comprising a locking pawl on one claw and locking cam and guide face on the other claw.

2. A conveyor as claimed in claim 1, further comprising cooperating stop surfaces on the two claws and on the locking pawl.

3. A conveyor as claimed in claim 1 wherein the claw of the driving crab is situated partly in the guide track, the free distance between the guide track and the spherical coupling member of said claw being smaller than the uncoupling stroke of the other coupling 5. A conveyor as claimed in claim 4, wherein the ball portion is mounted on the one-arm claw which extends in the direction of conveying, and said socket portion is mounted on the two-armed claw of said suspension crab which extends in the direction opposite to that of conveying, said locking pawl being arranged on the one-armed claw so as to be rotatable and the locking cam with the guide face being arranged on the twoarmed claw.

6. A conveyor as claimed in claim 5, wherein the locking pawl comprises a spherical supporting surface the width of which is smaller than the free distance between the arms of the two-armed claw, a locking projection and a recess between the supporting surface and the locking projection.

7. A conveyor as claimed in claim 1, further comprising a coding beam with coding elements for the automatic control of the switches on said suspension crab.

8. An overhead conveyor having a closed guide track, a transporting chain carried in said guide track, and a side track, at least one trolley arranged for transport in said tracks comprising a driving crab and a suspension crab, said driving crab being guided in said guide track and driven by said transporting chain, a curved claw provided on said driving crab and on said suspension crab, a detachable connection for coupling said suspension crab to said driving crab comprising a self-centering coupling between said driving and suspension crabs formed by spherically shaped coupling members carried by said curved claws, said claws arranged to face and overlap each other so that the spherically shaped members will cooperatively engage each other to effect coupling, safety means carried on said claws for preventing unintentional uncoupling, means for automatically coupling and uncoupling said crabs, and switch means for transferring the suspension crabs from one track to the other.

9. The overhead conveyor according to claim 8, wherein said safety means comprises a locking pawl mounted for pivotal movement on one of said claws and a locking cam and guide face mounted on the other of said claws.

10. The overhead conveyor according to claim 9, further comprising cooperating stop surfaces on said claws and on the locking pawl.

11. The overhead conveyor according to claim 8 wherein said curved claw of said driving crab is arranged within said guide track, the distance between the guide track and said spherically shaped coupling member on the curved claw of said driving crab being smaller than the stroke required for uncoupling the suspension crab from the driving crab.

12. The overhead conveyor according to claim 8 wherein the curved claw of said driving crab is onearmed claw and wherein the curved claw of said suspension crab is a two-armed claw, said spherically shaped coupling members comprising a ball portion carried on the end of said one-armed claw and a socket portion formed on the two armed claw in cooperation with the one-armed claw forming a guide for the suspension crab.

13. The overhead conveyor according to claim 12 wherein said one-armed claw extends in a direction of conveyance of said trolley and wherein said two-armed claw extends in a direction opposite to the direction of conveging.

14. he overhead conveyor according to claim 13, wherein said locking pawl is mounted for pivotal movement on said one-armed claw and said locking cam and guide surface is arranged on said two-armed claw.

15. The overhead conveyor according to claim 14, wherein said locking pawl comprises a spherical supporting surface the width of which is smaller than the distance between the arms of said two-armed claw, and further comprising a locking projection and a recess between the supporting surface and the locking projection.

16. The overhead conveyor according to claim 8, further comprising a coding beam with coding elements for automatic control of the switches connected to said suspension crab.

Claims

1. An overhead conveyor having an endless transporting chain and a closed single guide track which together form a main track, at least one local lower track forming a side track, a plurality of trolleys each comprising a driving crab and a suspension crab, said driving crab travelling in the guide track so as to be driven by the transporting chain, a detachable connection for coupling the suspension crab to the driving crab, means for automatically coupling and uncoupling the suspension crabs, switches for transferring the suspension crabs from one track to the other track, said detachable connection comprising a selfcentering coupling and safety means, the connection being adapted to be locked and unlocked automatically, said coupling comprising two cooperating spherical coupling members which are provided on curved claws one of which is provided on the driving crab and the other of which is provided on the suspension crab, which claws face each other and overlap each other, the safety means comprising a locking pawl on one claw and locking cam and guide face on the other claw.

3. A conveyor as claimed in claim 1 wherein the claw of the driving crab is situated partly in the guide track, the free distance between the guide track and the spherical coupling member of said claw being smaller than the uncoupling stroke of the other coupling member necessary for uncoupling.

4. A conveyor as claimed in claim 1, whereIn the driving crab has a one-armed claw and the suspension crab has a two-armed claw, and wherein said coupling members comprise a ball portion on the end of said one-armed claw and by a socket portion on the two-armed claw, the arms of the two-armed claw, in cooperation with the one-armed claw, forming a guide for the suspension crab.

5. A conveyor as claimed in claim 4, wherein the ball portion is mounted on the one-arm claw which extends in the direction of conveying, and said socket portion is mounted on the two-armed claw of said suspension crab which extends in the direction opposite to that of conveying, said locking pawl being arranged on the one-armed claw so as to be rotatable and the locking cam with the guide face being arranged on the two-armed claw.

12. The overhead conveyor according to claim 8 wherein the curved claw of said driving crab is one-armed claw and wherein the curved claw of said suspension crab is a two-armed claw, said spherically shaped coupling members comprising a ball portion carried on the end of said one-armed claw and a socket portion formed on the two armed claw in cooperation with the one-armed claw forming a guide for the suspension crab.

13. The overhead conveyor according to claim 12 wherein said one-armed claw extends in a direction of conveyance of said trolley and wherein said two-armed claw extends in a direction opposite to the direction of conveying.

14. The overhead conveyor according to claim 13, wherein said locking pawl is mounted for pivotal movement on said one-armed claw and said locking cam and guide surface is arranged on said two-armed claw.