Slider Crank Mechanism

Short-distance straight-line motion mechanism is very commonly used in practice. The straight-line motion is generally achieved by the following methods:

  • Thread driving is one adopted by most electric push rods on the market. It has the advantage of accurate positioning. Disadvantage: slower speed. 
  • Slider crank is also applied relatively widely, such as punching machine. Advantage: high speed and strong power. 
  • Pneumatic or hydraulic method is adopted by the cylinder. Advantage: high speed. Disadvantage: need for air source and incapability of positioning for simple cylinder.

The Makeblock system provides the cylinder which can make straight-line motion. However, in consideration of no portability of the air source, a Slider Crank Mechanism mechanism is set up with the parts of Makeblock to achieve short-distance straight-line motion. It has compact structure, high reciprocating speed and relatively reasonable cost.

1. U bracket + 8mm shaft clamp Fix the U bracket on the 8mm shaft clamp

2. 8mm shaft + double-hole beam (128) Fix the double-hole beam via the hole in the bottom surface of the clamp. Insert the 8mm shaft into the shaft clamp, without locking at that time. 

3. 3X3 bracket + 4x7x2ABS gasket Fix the 3X3 bracket on the double-hole beam. Pay attention to putting the 4x7x2ABS gasket between the bracket and the double-hole beam to raise the bracket and allow the hole in the center of the bracket and the 8mm shaft to be concentric 

4. Adjust the axial position of the 8mm shaft to fit it with the 3X3 bracket. Therefore, determine the position of the 8mm shaft, and then lock the screw on the shaft clamp to fix the 8mm shaft. 

5. Then, remove 3x3 connecting sheet.

6. Synchronous pulley 18T + synchronous belt 98XML + 4mmD shaft (56mm) + 2 bearings Insert the bearings into 8mm holes of the U bracket, fix the 18T synchronous pulley on the 4mm shaft with the grub screw, sleeve the synchronous pulley with the synchronous belt, and penetrate the shaft through the bearings to erect the shaft on the U bracket.

7. Synchronous pulley 62T + fixed driving disc Fix the fixed driving disc with the synchronous pulley 

8. 4mm shaft sleeve + gasket + 4x22mm screw + locknut + 8mm shaft-pulley connecting sheet + bearing Put the bearing in the 8mm hole at the top end of the 8mm shaft-pulley connecting sheet. Penetrate the 4x22mm screw through the through hole at the outermost end of the 62T synchronous pulley, mount the shaft sleeve and gasket, sleeve the 8mm shaft-pulley connecting sheet, and lock the locknut at last.

Make two such structures.

9. Part: gasket Installation method: sleeve the gasket on the outer side of the bearing on the 4mm shaft, then sleeve the module set up in the previous step on the 4mm shaft via the fixed driving disc, and lock the driving disc on the shaft with the grub screw. 

10. Part: 3x3 bracket + 4mm flange bearing + 4mm shaft sleeve + locknut + 4x14mm screw Procedure: Put the bearing in the 8mm hole at the lower end of the 8mm shaft-pulley connecting sheet. Penetrate the 4x14mm screw through the center hole of the 3x3 bracket and then through the bearing on the 8mm shaft-pulley connecting sheet, penetrate the shaft sleeve, and lock the locknut at last.

11. Part: 8mm polish shaft slide + M4x8 screw Procedure: Sleeve the 8mm shaft with the 8mm polish shaft slide, and then fix the 3x3 bracket with slide by the screw. 12. Part: 3x3 bracket + 4x7x2 gasket + locknut + M4x14 screw Procedure: Fix the 3X3 bracket on the double-hole beam with the screw, and pay attention to putting the gasket between the bracket and the double-hole beam to allow the hole in the center of the bracket and the 8mm shaft to be concentric. 

13. Part: double-hole beam 96mm + double-hole beam 32mm + M4x14 screw Procedure: fix the two newly added double-hole beams on the two end faces of the original double-hole beam

14. Up to now, the mechanical structure of Slider Crank Mechanism is finished: the 4mm shaft rotates to drive the synchronous pulley 62T to rotate, which is then converted into the straight-line motion of the polish shaft slide via the 8mm shaft-pulley connecting sheet. Add a power source for the Slider Crank Mechanism mechanism. We use DC 25 motor to drive the synchronous pulley on the 4mm shaft. Part: double-hole beam 160mm + 25 motor + motor bracket + double-hole beam 16mm + synchronous pulley 18T Fix the double-hole beam 160mm on the double-hole beam 32mm, lock the motor on the motor bracket, fix the motor with the double-hole beam 16mm, and fix the synchronous pulley 18T on the output shaft of the motor with the grub screw.

Sleeve the two 18T synchronous pulleys with the synchronous belt, tighten the synchronous belt by adjusting the position of the motor on the double-hole beam 160mm, then allow the whole motor mechanism to pass through the through hole in the double-hole beam 16mm, and lock it in the thread groove of the double-hole beam 16mm. Then, provide the power supply for the motor, and finish the whole Slider Crank Mechanism short-distance straight-line motion mechanism.

Parts list:

0824-128 Beam0824-96 Beam0824-32 BeamShaft Claming Hub 8mmBracket U1-BlueD Shaft 4x56mmFlange Bearing 4x8x3mmShaft Connector 4mm V2.0Plastic Spacer4x8x1Timing Pulley Slice 90T-B-BlueTiming Pulley 18TShaft Collar 4mmPlate A-BlueHexagon socket buttonhead screws M4×22Shaft D8×128mm-HBracket 3x3-BluePlastic Ring 4x7x2Linear Motion Slide Unit8mm0824-144 Beam0824-16 Beam5mm DC Motor Pack-Blue





















This mechanism is also very widely applied during DIY: Such as DIY small punch machine or DIV testing mechanism: for example, this mechanism is used for contacting the limit switch ceaselessly to test its life.