GB2462882A - Gripper mechanism for a robot including a rotary actuator - Google Patents

Abstract

A gripper mechanism consisting of a main housing (5a fig. 1) having a channel section, a pneumatically operated rotary actuator (6 fig. 1) driving a disc or uniform rise and fall cam 7, with levers 8, 9 pivotally attached at one end to the said cam 7 and at the opposite ends to linear slides and carriages 10, to each of which may be secured a gripper assembly by means of threaded holes (11 fig. 2). The cam may rotate through 180° and the levers 8, 9 may be shaped to accommodate this rotation. The position illustrated shows the cam 7 at the midpoint of its rotation, i.e. 90° from either extreme rotational position.

Description

IMPROVEMENTS RELATING TO GRIPPER MECHANISMS FOR

INDUSTRIAL ROBOTS

Field of the invention

The invention relates to the subject of robotics wherein grippers of various sizes and design configuration are used. In the main cylinders are used to convert angular movement into linear movement, the cylinder types in the main are pneumatic and in certain circumstances hydraulic cylinders are used when higher pressures of the grippers are required. Typical examples of prior art grippers are those disclosed in the following patent applications Nos. US 4,696,503; US 3,620,095; US 3,881,761 and US 4, 696,503.

All prior art applications disclosing the herein before subject matter are somewhat complex and require several parts to be replaced in the event of failure, fiwther more a high percentage of gripper device mechanisms, appear to be somewhat complex in design and therefore expensive to manufacture.

SUMMARY OF THE INVENTION

The present disclosed gripper device aims primarily in over coming the problems likely to be encountered with that of present conventional gripper mechanisms.

Basically this as been accomplished by using, where ever possible standard ready available commercial components and fittings.

The gripper can be easily replaced if and when required. The gripper can therefore perform a variety of tasks at a relatively low cost. This is mainly by reason that actuator and linkage drive system need not be changed each time the fijnction of the device is changed, by reason of the variation in both size and shape of the object to be picked up.

The main components of the said invention consist of a base housing member, an industrial pneumatically operated rotary actuator, a uniform rise' and fall' cam with levers pivotally attached at one end to the cam and the other end pivotally attached to linear slides and carriages.

The invention will now be described with aid of the accompanying drawings; Fig. 1 Is a cross-sectional side elevation.

Fig. 2 Plan view.

Fig. 3 Plan view showing part rotation of the cam.

Fig.4 Plan view showing cam and levers in closed position.

Item 5 fig. us the side elevation of the mechanism, having in the first part item 5a is the main housing of the mechanism, and for this description only is an aluminium alloy channel section having a width, depth and length of 6 inches, 3 inches and 600 millimetres in length, represented by the dimension lines D'and L' Fig. 1, and represented by the dimension W' fig 2.

Item 6 fig. 1 is a commercially available pneumatically operated rotary actuator, with the equivalent pressure of a pneumatic cylinder with a bore of 100 millimetres.

The said actuator will operate through 180 degrees clockwise and stop, a secondary Air feed signal to the said actuator, will cause a anti-clockwise movement returning to its start position. This rotation is identified in figure 2 by the arrows R'. Item 7 fig'l, 2, 3 and 4 is the cam consisting of a steel disc rigidly fitted to the actuator shaft I spindle.

Items 9 fig's 1, 2, 3 and 4 are shaped levers or links manufactured to specified dimensions from flat section steel. One end of the lever is pivotally connected to the cam with the opposite end connected pivotally connected to the carriage of a linear bearing assembly item's 10 fig's 1, 2, 3,and 4.

The left-hand and right-hand linear carriage assemblies will have the gripper assembly ( not shown) secured with screw fastening means, using the threaded holes 11.

The drawings fig's 2, 3 and 4 show the said levers / links in the following angular displacement formation. Fig. 2 shows their start position with the linear carriage assemblies items 10, at the extremity of their positions to both the left' and right' hand sides, defining the widest position of the grippers within this particular design layout.

Figure 3 shows a 90 degree movement (clockwise) of the said cam item 7, such that the levers I links can be considered to be at the Top-dead centre' of the cams stroke.

Further rotational movement through 90 degrees, as shown in fig. 4 will provide the grippers (not shown) with their maximum grip force,as the two inner faces of the said levers items 8 and 9 will lock against each other as identified by the letter X' flg.4.

Finally the upper surface of the channel section item 5 fig. 1 can have fitted top cover plates, one to the left and right hand side with a detachable cover at the centre for repair and maintenance purposes.