Palm-type mechanical gripper with variable-position and rotatable fingers and crank-rocker-slider parallel mechanism

Patent metadata

Field	Value
Publication number	US-10688668-B2
Application number	US-201716072186-A
Country	US
Kind code	B2
Filing date	Dec 8, 2017
Priority date	Apr 26, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A palm-type mechanical gripper with variable-position and rotatable fingers and a crank-rocker-slider parallel mechanism adopts crank-rocker-slider mechanisms and three identical flexible plate spring fingers, wherein one finger is fixed, and the other two fingers can rotate and move to achieve translational motions and are respectively and symmetrically installed on connecting rods or rockers on left and right sides. The crank-rocker-slider mechanism on the left side is an active driving structure and is driven by two stepping motors to respectively generate angular displacement of cranks and linear movement of sliders. The crank-rocker-slider mechanism on the right side is a driven mechanism and is driven at a constant speed by a pair of gears. The eccentricities of the cranks, the positions and angles of the two fingers respectively on the two connecting rods or rockers and the position of the other fixed finger can be changed through manual adjustment.

First claim

What is claimed is:

1. A shape adjustable mechanical gripper with variable-position and rotatable fingers and a crank-rocker-slider parallel mechanism, wherein
two ends of a linear guide rail are fixed by two guide rail supports installed on a base plate, two ends of an installation plate are respectively fixed on the two guide rail supports, the installation plate is provided with a series of holes located at different positions and used for a connection with a robot body, sizes of the series of holes correspond to a size of the robot body, and the series of holes located at different positions are beneficial to adjustment and connection;
a linear bearing penetrates through the linear guide rail to move, a movable base is fixed on the linear bearing, and a hinge shaft is fixed on the movable base with a first nut;
a lead screw nut is fixed on the movable base, and a lead screw stepping motor is fixed on the base plate and drives, through the lead screw nut, the movable base to drive the linear bearing to linearly move on the linear guide rail;

the hinge shaft penetrates through holes in a driven rocker and in a driving rocker, wear washers are respectively arranged on a left side and a right side of the driven rocker, and the driven rocker and the driving rocker rotate on the hinge shaft in opposite directions;
two layers of kidney-shaped grooves with different widths are coaxially milled on a horizontal face of the driving rocker, the driving rocker is connected with a connecting rod on a left side in a hinged manner through a hinge pin, a guide cylindrical face of the hinge pin has a diameter in clearance fit with a width of a wide kidney-shaped groove of the driving rocker, and after being tightened with a second nut, the hinge pin is integrated with the driving rocker;
the connecting rod has a thickness clearance and is capable of rotating in the hinge pin with respect to the driving rocker;
after the hinge pin is moved and then fixed with the second nut, a working length of the driving rocker is manually adjusted;
an end of the connecting rod is connected with a grooved crank in a hinged manner through a hinge pin, two layers of kidney-shaped grooves with different widths are also coaxially milled on the grooved crank, and similar to a connecting principle of the driving rocker and the connecting rod, a working eccentricity of the grooved crank is manually adjusted;
one end of a driving grooved crank is sleeved with a driving shaft, fastened on a flat face at one end of the driving shaft with a screw and used to transmit rotation torque of the driving shaft;
the grooved crank, a long sleeve, two mounted bearings, a short sleeve and a driving gear are installed on the driving shaft, a flat cylindrical section at an end of the driving shaft is inserted into a hole of a driving shaft of a stepping motor with the worm speed reducer in a clearance fit manner, the stepping motor with the worm speed reducer transmits torque to the driving shaft through the flat cylindrical section, and the torque is then transmitted by a flat key on the driving shaft to the driving gear;
an axial position of the driving gear is adjusted by regulating axis sizes of the long sleeve and the short sleeve;
a first mounted bearing is fixed on a gear cover plate, and an axial gravity generated by a grasped object is transmitted by a shaft shoulder face of the driving shaft to an inner ring of the first mounted bearing on the gear cover plate so as to be borne by the inner ring;
a second mounted bearing coaxial with the mounted bearing on the gear cover plate is fixed on the base plate;
the gear cover plate and the base plate are connected into an integrated structure through two guide studs, and two ends of each guide stud are provided with cylindrical faces in clearance fit with corresponding holes, and are then fastened with nuts, instead of the guide studs directly having thread connection with the base plate and the gear cover plate;
a driven shaft is supported by the two mounted bearings and a small mounted bearing, the two mounted bearings and the small mounted bearings are respectively fixed on the gear cover plate and the base plate, and in an axial direction, a shaft shoulder face of the driven shaft, a thick sleeve, a taper-hole gear, a taper sleeve and a flat round nut form a rotating body;
the driving gear is engaged with the taper-hole gear, the taper sleeve is disposed in a hole of the taper-hole gear, and by tightening the flat round nut, the torque is transmitted to the driven shaft under a wedge effect of a conical contact face;
an end of a driven grooved crank is sleeved with the driven shaft and fastened on a flat face at one end of the driven shaft with a screw, and rotation torque of the driven shaft is then transmitted to the driven grooved crank;
the taper-hole gear and the taper sleeve are separated by reversely unscrewing the flat round nut, and then a phase angle between the driving grooved crank and the driven grooved crank is adjusted, namely, the driving grooved crank and the driven grooved crank are symmetrical or asymmetrical in a horizontal direction;
a kidney-shaped groove is formed in the connecting rod and has a width in clearance fit with a diameter of a section of cylindrical face at a threaded end of a short finger holder, and the short finger holder is located at a position of the kidney-shaped groove of the connecting rod, capable of rotating by an angle with respect to the connecting rod and is fixed on the connecting rod with a third nut;
a first plate spring curved finger is installed on the short finger holder and provided with a fingertip curved part used to grasp an object in a pinching manner and a middle curved part used to grasp the object in a wrapping manner;
a long finger holder has a width in clearance fit with a width of a wide kidney-shaped groove in the base plate, and a threaded section of the long finger holder penetrates through a narrow kidney-shaped groove in the base plate and is fixed with a fourth nut so that a position of the long finger holder can be adjusted in the wide and narrow kidney-shaped grooves in the base plate, and the long finger holder is also provided with a second plate spring curved finger;
the shape adjustable mechanical gripper with the crank-rocker-slider parallel mechanism is provided with a driving crank-rocker-slider mechanism on a left side and a driven crank-rocker-slider mechanism on a right side;
the short finger holder is installed on the connecting rod on the left side, the medium finger holder is correspondingly installed on a connecting rod on the right side, and the first, second, and third plate spring curved fingers on the short finger holder, the medium finger holder and the long finger holder are completely identical in structure and size;
for a structure of the mechanical gripper, planes of the short finger holder, the medium finger holder, and the long finger holder are coplanar, wherein the three plate spring curved fingers are installed on the planes;
the short finger holder and the medium finger holder are respectively installed on the driving rocker and the driven rocker;
the narrow kidney-shaped groove of the driving rocker has a width in clearance fit with the diameter of the section of cylindrical face at the threaded end of the short finger holder, the short finger holder is located at a position of the driving rocker, capable of rotating by an angle with respect to the driving rocker and fixed on the driving rocker with a fifth nut;
the medium finger holder is installed on the driven rocker;
as the driving connecting rod is higher than the driving rocker in position and the driven connecting rod is higher than the driven rocker in position, after the short finger holder is installed on the driving rocker and the medium finger holder is installed on the driven rocker, installation faces of

Assignees

• Univ Jiangnan

Inventors

• Zhang Jun
• Shen Jian
• Lv Bin

Classifications

• B25J15/0009 Primary

  comprising multi-articulated fingers, e.g. resembling a human hand · CPC title