GB2101076A - Transferring workpieces between operating stations - Google Patents

Abstract

The apparatus comprises a turret connected to a pinion 14 and mounted on a base for rotation between a plurality of operating stations, a drive line 12, 13 for transmitting rotational movement from a drive motor 10 to the pinion 14 and thus the turret, a centering element in the form of a pin 32 mounted on a rotatable element 20 of the drive train for rotation therewith, and a control element 33 movable into engagement with the pin 32 when it is within a predetermined range of movement of an end position, one of the elements (33) including a cam surface 34 which engages a follower surface on the other element (32) whereby engagement of the control element 33 with the pin 32 drives the pin 32 into the end position. The movement of the turret between each operating station requires an integral number of revolutions of the rotatable element so that the centering element has the same position when the turret is in each operating station. <IMAGE>

Description

SPECIFICATION Mechanical handling apparatus This invention relates to mechanical handling apparatus.

Mechanical handling apparatus is commonly used to transfer components or workpieces between operating stations. Where the operating stations are spaced circumferentially about a central point, the apparatus may comprise a base, a turret rotatably mounted on the base for rotation between the operating stations and a drive line for transmitting rotational movement from a drive motor to the turret. With such apparatus a problem arises in ensuring that the turret is positioned accurately in each operating station and does not travel past the station under its own inertia when the motor is deactivated.

According to the present invention, there is provided a mechanical handling apparatus comprising a turret mounted on a base for rotation between a plurality of operating stations, a drive line for transmitting rotational movement from a drive motor to the turret, a centering element mounted on a rotatable element of the drive train for rotation therewith, movement of the turret between each operating station requiring an integral number of revolutions of thwrotatable element, and a control element movable into engagement with the centering element when the centering element is within a predetermined range of movement of an end position, one of the elements including a cam surface which engages a follower surface on the other element whereby engagement of the control element with the centering element drives the centering element into the end position.

If the end position of the centering element corresponds to the position which the turret occupies in one of the operating stations, the motor may be deactivated when the turret lies approximately at the operating station. Operation of the control element will then accurately position the turret at the operating station.

Since the movement of the turret between each operating station requires an integral number of revolutions of the drive member, the control member is effective to position the turret in each station.

In order to allow the position of the turret to be detected electronically, the drive line preferably includes a rotor having graduations thereon and a sensor for generating electrical signals in response to the movement of the graduations. The sensor may be optical, or magnetic. In the preferred embodiment of the invention the sensor is a magnetic sensor, and the graduations are in the form of notches in the rotor. This rotor may conveniently carry the centering element.

The centering element may comprise a pin and the central element may comprise a reciprocable cam element having a V-shaped cam surface engagable with the pin.

A preferred embodiment of the invention will now be described by way of example only, with reference to the drawings, in which: Figure 1 is a perspective view of apparatus in accordance with the invention; and Figure 2 is a perspective view, on an enlarged scale, of part of the apparatus of Fig.

1.

Referring to the drawings, mechanical handling apparatus 1 transfers workpieces in the form of straight bars from a furnace at a first station 1 to an annealing lehr at a second station 2 via on one or other of two pressing stations 3, 4 in which the straight bars are bent into generally U-shaped stabilisers bars for motor vehicles. The apparatus for effecting the transfer comprises a base 5, a turret 6 mounted on the base for rotation through 360 and carrying conventional tongs 8 for gripping the workpiece. The tongs 8 are mounted on a frame 9, which may be reciprocated vertically and radially relative to the base 5 to allow the workpieces to be transferred into and from the work stations.

Referring now to Fig. 2, the rotational movement of the turret 6 is effected by means of a drive motor 10 which is connected to the turret 6 by a drive line comprising a drive shaft 12, carrying a worm gear 1 3 which engages with a drive pinion 14 which is in turn connected to the turret 6. The gear ratio of the worm 1 3 and pinion 1 4 is such that the drive shaft 1 2 rotates an integral number of revolutions (for example 15) for each 90 of rotation between successive ones of the four work stations 1-4.

The drive shaft 1 2 carries a rotor 20 which has a series of graduations 21 in the form of notches around its circumference. A magnetic proximity sensor 22 is mounted adjacent the circumference of the rotor 20. The sensor 22 is of the conventional magnetic induction type which generates an electrical signal in response to the movement of the graduations 21 therepast. These signals are processed electronically in a conventional manner in a control unit 30 (Fig. 1) to provide electronic control signals for operating the drive motor 10.

The rotor 10 carries a centering element in the form of a pin 32 which extends axially from one face of the rotor 20. A control element 33 comprising a plate having a Vshaped cam surface 34 is positioned adjacent the rotor 20 in radial alignment with the pin 32 and is reciprocable by means of a pneumatic motor 35 into and out of engagement with the pin 32 when the pin is within a 45 of rotation of an end position, which is illustrated in Fig. 2. This position of the pin 32 corresponds to the position of the turret 6 in any one of the four work stations 1-4.

In operation, the turret is indexed between the four work stations 1-4 in accordance with a predetermined sequence of events by appropriate operation of the motor 10 in forward and reverse directions under the control of the control unit 30. As the drive motor 10 rotates, its rotational movement is transmitted along the drive shaft to the drive pinion and thereby to the turret. The position of the turret at any time can be determined by counting the pulses generated in the sensor. As the turret approaches a work station in which it is required to stop, the motor is deactivated and the pueumatic motor 35 is activated. Since the pin 32 always lies in the end position whenever the turret is in any one of the work stations, the pin 32 should always be aligned with the axis of movement of the cam element 33. In practice the inertia of the turret may carry the turret past the work station, in which case the pin 32 will be moved out of its end position. However, the engagement of the cam surface 34 with the pin 32 will drive the pin 32 back into the end position, thereby accurately positioning the turret in the work station.

Claims (4)

1. Mechanical handling apparatus comprising a turret mounted on a base for rotation between a plurality of operating stations, a drive line for transmitting rotational movement from a drive motor to the turret, a centering element mounted on a rotatable element of the drive train for rotation therewith, movement of the turret between each operating station requiring an integral number of revolutions of the rotatable element, and a control element movable into engagement with the centering element when the centering element is within a predetermined range of movement of an end position, one of the elements including a cam surface which engages a follower surface on the other element whereby engagement of the control element with the centering element drives the centering element into the end position.

2. Apparatus according to Claim 1 wherein the rotatable element comprises a rotor having graduations thereon the rotor being associated with a sensor for generating electrical signals in response to the movement of the graduations.

3. Apparatus according to Claim 1 or Claim 2 wherein the centering element comprises a pin carried by the rotatable element, and the control element comprising a Vshaped cam surface is reciprocable into engagement with the pin.

4. Mechanical handling apparatus substantially as hereinbefore described with reference to the drawings.