GB2032305A

GB2032305A - Rotary index table devices

Info

Publication number: GB2032305A
Application number: GB7931039A
Authority: GB
Original assignee: Poulton & Clarke
Current assignee: Poulton & Clarke
Priority date: 1978-09-07
Filing date: 1979-09-07
Publication date: 1980-05-08
Also published as: GB2032305B

Abstract

A multi-station rotary index table has an indexing drive mechanism with a plurality of drive transmitting rollers (27) arranged to be engaged successively by a retractable latch member (43) on a reciprocating slide (28). The slide (28) is driven by a pneumatic piston and cylinder device and two abutments (39,40) are arranged to engage rollers (27) after forward movement of the slide member preventing forward or reverse movement of the table. <IMAGE>

Description

SPECIFICATION Improvements in or relating to rotary index table devices The invention relates to a rotary index table device and more particularly to such a device arranged to be accurately located in a succession of station positions.

It is an object of the present invention to provide a rotary index table device with an improved indexing drive mechanism which simply and accurately locates the table in a succession of different station positions.

The present invention provides a multi-station rotary index table device comprising a rotary table mounted on a shaft and an indexing drive mechanism arranged to rotate said shaft about its axis and thereby advance the table through a succession of indexed positions. Said drive mechanism comprising a plurality of drive transmitting members connected to said shaft and distributed around the axis of said shaft at positions corresponding to successive index stations, a reciprocating index slide member and a drive device arranged to effect forward and return strokes of the slide member, said slide member being provided with a retractable latch member movable between a position engaging one of said drive transmitting members thereby effecting a drive connection between the slide member and the shaft during a forward stroke of the slide member, and a retracted position at which no drive connection is effected during a return stroke of the slide member, said indexing drive mechanism being provided with a first abutment face which acts as a stop arranged to engage one of said drive transmitting members after forward movement of the slide member thereby preventing further advance of the table for that index stroke, and a second abutment face arranged to engage one of the drive transmitting members at the end of each forward stroke and prevent reverse movement of the shaft so that at the end of the forward stroke of the index slide the shaft is locked in position and prevented from rotation in either direction.

Preferably the drive transmitting members each comprise a roller.

Preferably the retractable latch member comprises a latch pivotally mounted on the slide member and provided with a recess for engaging a drive transmits ting roller.

Preferably a pneumatic piston and cylinder device is provided to hold the latch member in a projecting position engaging a drive transmitting member.

Preferably the said first and second abutment faces are provided on said slide member.

Preferably the two abutment faces are arranged to engage respectively adjacent drive transmitting members when the slide member is in the forward position, thereby locking the shaft in a fixed position, the two abutment faces extending perpendicular to each other so that one prevents forward movement of one drive transmitting member and the other prevents reverse movement of the adjacent drive transmitting member.

In an alternative arrangement the first abutment face is provided on the slide member and the second abutment face is provided by a reverse movement stop member. In this case, the slide member may be provided with two additional abutment faces arranged to engage respectively adjacent drive transmitting members when the slide member is in the retracted position, thereby locking the shaft in a fixed position, the two additional abutment faces extending perpendicular to each other so that one prevents forward movement of one drive transmitting member and the other prevents reverse move ment of the adjacent drive transmitting member.

Preferably in the alternative arrangement the slide member is provided with a stepped surface adjacent the drive transmitting members, the said first abut ment face of the slide member being provided by part of the stepped surface at a middle level located towards a trailing end of the slide member, the said additional abutment faces being provided on a part of the stepped surface having a raised level towards a leading end of the slide member with one of the abutment faces providing a step in the slide member, and the stepped surface further including an intermediate zone of low level adjacent the retractable latch member thereby permitting passage of a drive transmitting member when engaged by the latch member during a forward stroke of the slide member.

Preferably said drive device comprises a pneumatic piston and cylinder device. Preferably stop means is provided to control the length of stroke of the slide member.

A pivoted latch member may be resiliently biased to an operative position engaging one of the drive transmitting members and preventing reverse movement of the shaft.

Preferably the rotary table is mounted on a housing from which the shaft projects, the housing containing the indexing drive mechanism.

Preferably the housing is provided with a plurality of flat faces extending around the periphery of the table whereby selected operating deives may be mounted on said faces for effecting operations at selected stations on the rotary path of the table. The housing may be octagonal.

Preferably the housing is mounted on a stand.

Two embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a perspective view of a rotary index table device embodying the present invention, Figure 2 is a vertical section through part of the indexing drive mechanism used in the device of Figure 1, Figure 3 is a view on the line A-A in Figure 2, Figure 4 is a view on the line B-B in Figure 3, and Figure 5 is a view similar to Figure 3 of a preferred alternative embodiment.

The rotary index table device of this example comprises a rotary table 11 mounted on a shaft 30 projecting from a housing 13. The housing 13 contains an indexing drive mechanism shown in Figures 2, 3 and 4, and is mounted on a stand 14. In this particular example the stand is shown with a base plate 15 resting on the ground with the axis of the stand extending vertically so that the table 11 is arranged to rate in a horizontal plane.

The housing 13 has a plurality of flat faces 16 and in this particular example is octaganol. Each of the faces 16 may have mounted thereon an operating device 17 having an asociated operating tool 18 adjacent the periphery of the table 11. The device 17 may contain the necessary drive mechanism or programmed control means for the tool 18 so that this tool 28 may carry out a required operation at a particular station in the rotary path of the table 11 and thereby act on a device conveyed by the table 11 through a succession of operating stations. Itwill be understood that the tool 18 and mechanism 17 may be selected to suit a variety of possible operations and these can be positioned on any one or more of the faces 16 of the housing so that a required combination of operations may be carried out.If desired, more than one operating tool may be mounted on each oftheflatfaces 16.

The indexing drive mechanism will now be de scribed in greater detail with reference to Figures 2, 3 and 4. The table 11 is mounted on the upper end of a rotary shaft 20 mounted on a sleeve 23 and the lower bearing is mounted in a plate 24. The sleeve 23 and plate 24 are both secured to a rigid support plate 25 which is fixed to the housing 13. The table 11 is secured to the shaft 20 so that the two rotate together. At its lower end, the shaft 20 carries an assembly 26 which includes a plurality of drive transmitting rollers 27 equally spaced around an annular path concentric with the axis of the shaft 20.

In order to rotate the shaft 20, the rollers 27 are arranged to engage, in turn, an index slide member 28 slidably mounted in an index block 29 which is rigidly attached to the support plate 25. The slide member 28 is linked at one end by a tie plate 30 to a piston rod 31 of a pneumatic piston and cylinder device 32. The piston and cylinder device 32 is mounted on a ram plate 33 which is in turn secured to the index block 29.

The index slide 28 is movable in forward and return strokes by operation of the piston and cylin der device 32. The slide 28 has an upper (as seen in Figure 3) surface 35 adjacent the rollers 27 which is stepped and has ground abutment faces. At a trailing end 36, the surface 35 has a middle level and provides a first abutment surface. At the opposite end 38, that is the leading end of the slide member, the slide member has a raised portion providing additional abutment faces 39 and 40. The two faces 39 and 40 extend perpendicular to each other and the face 40 acts as a step in the upper surface of the.

slide member. The slide member also includes an intermediate region 41 which is in effect recessed to provide a low surface level. The slide member 28 also includes a central recess 42 in which is located a pivoted latch member 43. The latch member is mounted on a pivot pin 44 and is spring urged by a spring 45 to an outwardly projecting position where a part-circular recess 46 in the latch member en gages one of the rollers 27. The slide 28 also incorporates a pneumatically operated stud 50 arranged to project from a pneumatic piston and cylinder device 51 so that the stud engages one end of the latch member 43 may therefore hold the latch member 43 in the outwardly projecting position engaging a roller 27.

The indexing drive mechanism also includes an anti-reverse pawl 60 mounted on a pivot pin 61 on a pawl block 62 which is also secured to the support plate 25. The pawl 60 is urged outwardly from the block 62 by a compression spring 63 so that one end of the pawl 60 engages a reverse face of one of the rollers 27 as shown in Figure 3. The pawl is movable against the action of the spring 63 so as to move out of the path of the rollers 27 when they rotate in the forward direction, that is the anti-clockwise direction as shown in Figure 3.

In operation, the piston and cylinder device 32 is actuated so as to move the index slide 28 to the right as shown in Figure 3. At the same time, pneumatic pressure is supplied to the piston and cylinder device 51 so that the stud 50 retains the latch member 43 in engagement with the adjacent roller 27. Movement of the slide 28 in the advance direction, that is to the right as shown in Figure 3, causes the latch member 43 to move the engaged roller to the right and thereby rotate the shaft 20 from one indexed station to the next. The piston and cylinder device 32 is a cushioned device so as to cushion impact at the end of the forward stroke.

However, the precise positioning of the index slide at the end of its stroke is controlled by a stop 70 secured to one end of the index slide engaging a further stop 71 mounted on the index block 29. As the shaft 20 rotates, the pawl 60 is forced out of the path of the rollers 27 against the action of the spring 63. Precise stopping of the table 11 in the next indexed station is controlled by engagement of the roller 27, following that engaged in the latch 43, engaging the first abutment surface 36 on the trailing end of the index slide. As can be seen from Figure 3, the intermediate surface level 36 is positioned in the path of the rollers so that the table 11 is accurately stopped in the next indexed position as soon as the following roller 27 engages the first abutment surface 36.At the same time, the pawl 60 is urged by the spring 63 to fall into position behind one of the rollers 27 thereby preventing any reverse movement of the shaft 20. In this position, the table has accurately arrived at the next index station and air pressure is released from the piston and cylinder device 32 and 51. The piston and cylinder device 32 is then subjected to air pressure on the reverse side of the piston so as to commence a reverse stroke of the index slide 28. Due to retraction of the stud 50, the latch member 43 can be pushed down into the recess 42 in the slide member 28 as an inclined face 73 on the latch member 43 slides over the roller 27.

When the return stroke is almost complete, the latch member 43 will of course be permitted to rise again under the action of the spring 45 so as to engage the next roller 27 in readiness for the nextforward drive stroke. During this return movement of the index slide, the first abutment face 36 on the slide member will of course move out of engagement with the roller 27 which came into contact with it on the previous forward stroke so that the rollers 27 are no longer prevented from rotating by the first abutment surface 36. However, the additional abutment faces 39 and 40 are moved back into the position shown in Figure 3 where the surface 39 engages the reverse face of one roller 27 so as to prevent reverse movement of the shaft 20 and the other abutment face 40 engages the adjacent roller 27 and prevents forward movement of the shaft 20.In this way, the assembly of rollers 27 and thereby the shaft 20 and table 11 is locked in position by the index slide 28 and no movement can occur in either direction until the next forward movement of the index slide 28.

It will be appreciated that once the next indexing stroke occurs, the abutment face 40 moves forwards with the index slide so as to permit advance movement and the roller 27 which is engaged by the latch member 43 is at that time adjacent the low intermediate region 41 of the slide member 28 so that rotation of the assembly of rollers 27 can occur.

It will of course be understood that one forward and return movement of the index slide 28 is carried out in order to advance the table 11 from one indexed position to the next.

Figure 5 is a view similar to Figure 3 showing a modified arrangement of the indexing mechanism forming part of a preferred embodiment of the invention. The example is generally similar to that described with reference to Figure 3 and similar reference numerals have been used for similar parts.

The main change is that the slide 28 has the abutment faces 39 and 40 arranged so that they hold the table in an accurately indexed position at the end of a forward stroke rather than at the end of a return stroke. Consequently the slide 28 is shown in Figure 5 in the forward position whereas in Figure 3 it is shown in the return position. As previously de scribed with reference to Figure 3, the slide member 28 is linked at one end by a tie plate 30 to a pneumatic piston and cylinder device. The slide member 28 has a central recess 42 in which is located the pivoted latch member 43. A pneumatical ly operated stud 50 is arranged to engage one end of the latch member 43 to hold the latch member in the outwardly projecting position engaging a roller 27.

However, the abutment faces 39 and 40 which were previously provided at the leading end of the slide are now provided at the trailing end of the slide. The two faces still extend perpendicular to each other so that the face 40 forms a vertical step in the upper surface of the slide member. The abutment faces 39 and 40 are provided by two wall members 75 spaced apart to provide a channel between them. In this channel is pivotally mounted a lever 76 urged by a spring 77 to a position such that the lever 76 projects above the abutment face 39 and is engaged by an advancing roller 27 before the roller meets the abutment face 39. In this way the lever 76 acts as a damping device and absorbs some of the kinetic energy of the rotating mechanism before the advancing roller 27 engages the abutment face 39.

The abutment face 35 which was provided at the trailing end of the slide in Figure 3 is no longer required and is now replaced by the abutment faces 39 and 40 in Figure 5. The recess 41 in the top surface of the slide shown in Figure 3 is no longer necessary and is replaced by a part-circular recess which coincides with the part-circular recess 46 in the latch 43 as shown in Figure 5.

The anti-reverse pawl 60 is still provided in the arrangement shown in Figure 5 and is the same as previously described. The stop 71 is mounted on an hydraulic damping cylinder arrangement 78 and a similar hydraulic damping arrangement 79 is provided at the other end of the block 29 for engagement by the plate 30 when the slide moves in the return direction. These damping devices may be oil filled and may be built into part of the block 29.

Alternatively passages 80 and 81 are provided for connection to external hydraulic dampers.

The operation of this preferred embodiment in Figure 5 is generally similar to that previously described in that forward movement of the slide 28 causes the raised latch 43 to move the rotary table to the next index position. However, in this example the table is locked in the next indexed position at the end of the forward stroke of the slide 28 by engagement of the abutment surfaces 39 and 40 with two adjacent rollers 27. The anti-reverse pawl 60 will also fall into position at the end of the forward stroke. The table can then be held accurately in position for any period of time to suit the tooling operation which is carried out while the indexed table is in that position.When it is required to advance the table the slide 28 must first be retracted in a manner similar to that previously described so that the latch 43 may be in a position to engage the next roller 27. It will be appreciated that in this preferred arrangement the mechanism indexes the table at the end of the forward stroke and positively locks it in that position without the need to effect a return stroke of the slide 28. This allows the table to be advanced and locked in position at the next indexed position in a very short time interval.

The above described examples provide particularly simple and effective ways of effecting the necessary indexing movement and the table is accurately held in position in each indexed station with no possibility of any overrun in the forward direction or rebound in the reverse direction on arrival at each index station.

The index tables previously described are particularly suitable for carrying out a sequence of automatic operations on a succession of devices which are conveyed by the rotary table. In the particular examples described, each arrangement forms a 12 station indexing arrangement but any other number of stations may be used. The table may be used for a wide variety of operations including for example the assembly of potentiometers, filling of bottles or capsules, assembly of connections in electrical industry, manufacturing techniques such as drilling, pressing, spraying or testing as well as uses in the confectionary industry.

It will be appreciated that the invention is not limited to the details of the examples described above.

In some cases it may be desirable to mount the housing 13 on a support other than the stand 14 and in such cases the housing may be used in orienta tionsotherthanthatshown in Figure 1.

Claims

1. A multi-station rotary index table device comprising a rotary table mounted on a shaft and an indexing drive mechanism arranged to rotate said shaft about its axis and thereby advance the table through a succession of indexed positions, said drive mechanism comprising a plurality of drive transmitting members connected to said shaft and distributed around the axis of said shaft at positions corresponding to successive index stations, a reciprocating index slide member and a drive device arranged to effect forward and return strokes of the slidemember, said slide member being provided with a retractable latch member movable between a position engaging one of said drive transmitting members thereby effecting a drive connection between the slide member and the shaft during a forward stroke of the slide member, and a retracted position at which no drive connection is effected during a return stroke of the slide member, said indexing drive mechanism being provided with a first abutment face which acts as a stop arranged to engage one of said drive transmitting members after forward movement of the slide member thereby preventing further advance of the table for that index stroke, and a second abutment face arranged to engage one of the drive transmitting members at the end of each forward stroke and prevent reverse movement of the shaft so that at the end of the forward stroke of the index slide the shaft is locked in position and prevented from rotation in either direction.

2. A multi-station rotary index table device according to claim 1 in which said first and second abutment faces are provided on said slide member.

3. A multi-station rotary index table device according to claim 2 in which the two abutment faces are arranged to engage respectively adjacent drive transmitting members when the slide member is in the forward position, thereby locking the shaft in a fixed position, the two abutment faces extending perpendicular to each other so that one prevents forward movement of one drive transmitting member and the other prevents reverse movement of the adjacent drive transmitting member.

4. A multi-station rotary index table device according to claim 1 in which the first abutment face is provided on the slide member and the second abutment face is provided by a reverse movement stop member.

A multi-station rotary index table device according to claim 4 in which the slide member is provided with two additional abutment faces arranged to engage respectively adjacent drive transmitting members when the slide member is in the retracted position, thereby locking the shaft in a fixed position, the two additional abutment faces exending perpendicular to each other so that one prevents fon ard movement of one drive transmitting member and the other prevents reverse movement of the adjacent drive transmitting member.

6. A multi-station rotary index table device according to any one of the preceding claims in which the drive transmitting members each comprise a roller.

7. A multi-station rotary index table device according to claim 6 in which the retractable latch member comprises a latch pivotally mounted on the slide member and provided with a recess for engaging a drive transmitting roller.

8.A multi-station rotary index table device according to any one of the preceding claims in which said drive device comprises a pneumatic piston and cylinder device and stop means is provided to control the length of stroke of the slide member.

9. A multi-station rotary index table device according to any one of the preceding claims in which the rotary table is mounted on a housing from which the shaft projects, the housing containing the indexing drive mechanism and being provided with a plurality of flat faces extending around the periphery of the table whereby selected operating devices may be mounted on said faces for effecting operations at selected stations on the rotary path of the table.

10. A multi-station rotary index table device substantially as hereinbefore described with reference to Figures 1 to 4 or Figure 5 of the accompanying drawings.