GB2467007A - Rotary actuated linear mini gripper device - Google Patents

Abstract

A gripper mechanism for industrial robots comprises a main base housing 6, a pneumatic rotary vane actuator 26, two linear slide plates 16 to carry gripper fingers and linked to stub shafts (13 fig 2) on either side of a circular disc 12 of a cam (11 fig 2) fitted to the spindle of the actuator 26, the stub shafts (13 fig 2) engaging slots (17 fig 3) in the slide plates 16 and the housing 6 including a through hole 29 for a proximity switch 28 to detect the linear position of the slide plates 16.

Description

MINI GRIPPER MECHAMSM FOR INDUSTRIAL ROBOTS

Field of invention

The invention relates to the subject matter of robots, wherein grippers of various sizes and design features are employed, The said grippers have fingers attached in a manner compatible with the design criteria,the said fingers are in various design configurations to satisfy the dimensions and weight of the objects that will be gripped and manoeuvred into their next requisite position, predicted by the production programming.

By present conventional methods the main or predominant method of converting angular movement, into linear movement (Linear movement being the one most commonly used). In the main pneumatic cylinders are used for the conversion of movement, and in certain circumstances hydraulic cylinders are used, when higher pressures are required.

Typical examples of prior art Grippers' are those disclosed and described with the accompanying drawings, in the following patent applications No's US 4, 696, 503; US 3, 620, 095 and US4, 696, 503.

All prior art applications disclosing the herein before subject matter, are both complex and require several parts that would inevitably require replacing in the event of failure of the gripper mechanisms. The complexity of the herein before gripper designs, and those used in conventional present usage will be expensive to both produce and maintain.

SUMMARY OF THE INVENTION

The present invention related in this patent application, primarily aims in over coming the said problems likely to be encountered, with that of the present conventional gripper designs.

A fizrther relevant feature is by reason of its simplicity and using a limited number of moving parts, enables a design to be produced in a much smaller size, than that which would not be possible on more complex gripper mechanisms.

Cost effectiveness in manufacture as been further achieved by using where possible readily available standard commercial components and fittings.

The said 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 the gripper drive plates fitted within the mechanism, need not be changed each and every time a fI.inction of the device is changed.

With exception of the bought out commercial parts, the remainder of the components are manufactured from an alloy, and for this description only is that of a specified aluminium. Finished, by hardened anodising.

The main components of the invention consist of a main base, an industrial pneumatically operated rotary vane actuator, a uniform rise' and fall' cam, engaged positively within slide plates mounted on a commercially available linear ball slides and carriages.

Proximity switches are used which will depict accurately the open' and closed' positions of the grippers. Adequate securing locations are provided for captivating the robots finger arrangement to the said grippers.

The invention will now be described with aid of the accompanying drawings.

Fig. 1. A plan view of main housing Fig. 2. plan and end elevation.

Fig. 3 Plan, Side and end elevations.

Fig. 4 Plan and end elevation.

Fig. 5. Assembly of mechanism.

Item 6 Fig. 1 is the main housing, shown in plan view from the top/open end of the main housing. for this description only having a width, length and depth represented by the letters W', and L' where W' = 48 millimetres L' = 116 millimetres, the depth is not shown in this view and is 20 millimetres.

A recessed slot item 7, having closed ends is machined the fhll inside length of item 5, having a series of threaded holes items 8. spaced at specified dimensions within the said slot 7, within the remaining material within the base of the housing item 6. This will enable the linear ball slide rail to be secured in position.

A hole item 9 is provided at the centre of the base item 6, and is provided to accomadate the mounting for a pneumatically operated vane actuator, which will be fitted on assembly and retained in position by screw fasteners, using the threaded holes items 10. The said actuator is of the rotary vane type and commercially readily available in various sizes. Having pressure ratings directly proportional to that of pneumatic cylinders, for example only 10, 15, 20, 30, 40 50, 63, 80 and 100 millimetre diameter cylinder bore sizes, and for this description only will use the 10 millimetre size This size of actuator as a spindle diameter of 5 millimetres.

Item 11 Fig. 2 is the cam, having two stub shaft members items 13 and 13 a which are integral parts of the centre disc item 12, having a through hole item 14 enabling the cam item 11 fig. 2 to be assembled on the 5 millimetre diameter spindle of the rotary vane actuator item 25 fig. 5. A threaded hole 15 fig. 2 will be used for a specified grub screw size, to locate and retain positively the cam item 11 in position on the said actuator spindle.

Item 16 fig. 3 are the two slide plates, one will be fitted at the left-hand side (when viewed from the top' ), and the other slide plate on the right-hand side. The left-hand is that shown in fig. 3. Item 16 fig. 3 shown in various view positions, reference view A' is the top I upper plan view. A closed end recessed slot item 17 fig. 3, on assembly will be positioned on the upper most of the stub shaft members item 13 fig. 2, with both the slot item 17 and the said stub shaft having compatible dimensions to provide a side fit when in operation. The six threaded holes 20 fig. 3 will provide securing points for the robot fingers (not shown). Item 20a fig. 3 is a location recess for the said finger assembly. The lower groove 20 b will be located on the linear ball slide not shown), and will have sufficient clearance to allow the slide plates with the fitted linear ball carriage assembly to locate positively in a downwardly direction on the linear slide rail. The four socket head holes items 19 will provide for socket head cap screws, to retain rigidly in position a linear ball slide (not shown), A second slide plate item 16 fig. 3 reference the right-hand slide plate, this slide plate will not have a recessed slot item 17 fig. 3 where in a through slot of identical size to the recessed slot item 17 will be provided to allow the actuator spindle to pass through into the cam item 11 fig 2. This will allow the cam to be located and secured on the actuator spindle with the lower spigot shaft item 13a fig. 2 locating within the said through slot. Note:-the right-hand slide plate item 16 fig. 3 reference the dimension represented by the letter d' will require to be increased by the thickness of the cam disc part item 12 fig 2, by the thickness represented by the dimension t' item 12 fig.2.

The tongue like portion item 16a fig. 3 will then be in a lower position shown by the chain-dot outline. By reason that the base line of the said slide plate as now increased in length, The groove item 20b will require to be extended into the tongue like portion item 16, to ensure there is sufficient clearance at the inner end of the linear slide rail.

For reference only the said groove will have a closed end within the said tongue.

Final assembly drawing fig. 5 will show in clearer detail the two positions of the slide plates items 16 fig. 3.

Item 21 fig. 4 is a mounting plate for retention of a standard commercial type Proximity switch (not shown), the through hole 22 fig. 4 will house the said switch and will be held captive by screw fastening means within the threaded hole 23 fig. 4.

A closed end slot 24 flg.4 will allow fine adjustment of the said switch, having a screw fastening means within the slot and located within a compatible threaded hole ( not shown) in the underside of the base in the main housing item 6 fig. 1. For positional reference see item 6 fig. 1. The said mounting plate and fitted switch will be positioned by having one switch at each side of the base of the main housing item 6 fig. 1,The position of one switch is shown in feint outline in the plan view fig. 1.

Fig.5 is an assembly drawing, shown in plan view in the direction of arrow F', reference fig. 1, and turned through 180 degrees.

The main housing member item 6 fig. 1 having a series of threaded holes items 10 within the base will allow the rotary vane actuator item 26 to be fitted in position within the retaining hole item 9, and secured in position with socket head cap screws (not shown). The linear ball slide key item 27 can also be fitted within the slot item 7 fig. 1, one key will be fitted each side of the centre line and secured with socket head screws within the threaded holes items 8 fig. 1. The lower slide plate item 16 with the fitted linear slide rail carriage can now be located in position at the right hand side,( Note the additional depth of recess indicated by the arrow R' ) to allow clearance for the cam disc item 12 fig. 2, and the upper spigot shaft item 13a fig. 2.

The cam item 11 fig. 2 can now be fitted to the spindle of the actuator and retained in position by a specified screw in the threaded hole! 5 provided in the spigot shaft.

The upper left hand side slide plate item 16 fig. 3,is then fitted in position on the top spigot shaft of the said cam Item 21 fig. 4 is the bracket for housing the proximity switch item 28 fig. 5 within the hole 22, and retained in position by screw fastening means within the threaded hole 23. The said bracket is secured to the base of the main housing item 6 fig's 1 and 5 by screw fastening means, whilst adjustment can still be achieved by the slot item 24 fig. 4. A hole / slot item 29 fig. 5 is provided within the base of the main housing, directly in line with the said proximity switch, this will enable the proximity switch to accurately identif' the exact position of the slide plates items 16 fig' 3 and 5.

This is achieved by using specified screws fitted within the threaded holes items 25 fig. 3 which are located on the lower sides of the slide plates ( note one set only are required to detect the open and closed positions of the slide plates). For reference only the screw heads of these specified screws will act as flags' for the said proximity switch to register.

BRIEF METHOD OF OPERATION

The cam item 11 fig. 2 and for this description only as a throw I displacement of the spigots items 13 and 13a of 4 millimetres. This will cause in one half revolution of the actuator spindle, (180 degrees actuation of the spindle), a total movement of 8 millimetres on one slide plate item 16 fig. 3. This will execute a total movement between both slide plates of 16 millimetres, providing the same movement of 16 millimetres to the attached finger assemblies (not shown).

The rotary vane actuator will move 180 degrees in a clockwise direction and then rotate through 180 degrees in an anti-clockwise direction.

Finally, the inlet' and outlet' ports (not shown), for the compressed air are located on the outer circumference of the actuator housing. each having a built-in air-flow regulator for increase or decrease in pressure to the said actuator. This will enable the grip force on the finger assemblies to be adjusted as required.

Claims (4)

1. CLAIMS1. A Mini Gripper device mechanism consisting in the first part a main housing having two longitudinal sides and closed ends, with a base and open top part, a pneumatically operated rotary vane actuator is secured by screw fastening means at the centre of the base, attached to the said actuator spindle / shaft is a circular disc cam, having two stub shafts one to either side of the said disc, these are positioned on a specified P.C.D. (to provide the required displacement of the cam), attached to the stub shafts are two slide plate members having linear carriages and slides at their lower part, the said actuator revolves 180 degrees clockwise and then rotates anti-clockwise, causing the two said slide plates to move forwardly towards each other and a further anti-clockwise rotation, will cause them to move outwardly, a fitted proximity switch positioned at one end on the underside of the base will detect the linear position of the said slide plates.
2. 2. A Mini Gripper device mechanism as claimed in claim 1, whereby the said Proximity switch having external fastening means, can be easily adjusted without interference to the inner mechanism parts.
3. 3. A Mini Gripper device mechanism as claimed in claim 1, whereby the inlet and outlet ports for the compressed air, each having Air flow regulators, enables the grip force on the finger assemblies attached to the slide plates, to increase and decrease their grip force to satisfy the production requirements.
4. 4. A Mini Gripper device mechanism as claimed in any preceding claim and substantially as herein before described with reference to the accompanying drawings. * * ***. * *** e..� * I 5I ** * *0S* * *I I. III......S