RU2312008C1 - Combination type mechanism with complex motion of outlet links - Google Patents

Abstract

FIELD: mechanisms and apparatuses used for maintaining machines, machine tools, presses and other equipment.

SUBSTANCE: combination mechanism includes transfer mechanism, actuating mechanism with jaws for clamping articles and drive unit. Transfer mechanism is in the form of cam-gear mechanism having cam, pusher in the form of toothed rack and outlet link in the form of pinion engaged with toothed rack. Actuating mechanism is in the form of lever-cam mechanism having driving link in the form of rotary rod whose rocking center is coincided with center of rotation motion of pinion; outlet links jointly coupled with rotary rod through pin and stationary cam-follower with shaped grooves for joining with outlet links. Rotary rod is rigidly joined with pinion; pin is secured to end of rod. On free ends of outlet links rollers are mounted for engaging with shaped grooves in follower body.

EFFECT: lowered number of kinematics pairs, reduced energy consumption of engaging surfaces for friction, reduced wear degree of friction pairs, shortened time period of idling intervals, enhanced accuracy and operational efficiency.

2 cl, 1 dwg

Description

The present invention relates to mechanisms with a complex movement of the output links, which are used to perform auxiliary operations in the maintenance of machines, machine tools, presses and devices for various purposes. Such manipulation mechanisms that simulate certain movements of a person’s hands provide for the capture of the product (object of manipulation), its movement from one position to another, release and transfer of the product.

It is known, for example, a handling device that provides for the capture of the product, its movement along an arc of a circle and its release, containing an actuator with jaws for gripping the products, a rotation mechanism and a hydraulic drive (Krainev A.F. Dictionary of Mechanisms. - M.: Mechanical Engineering, 1987. - S. 9 and 10, fig.a).

The main disadvantage of this device is the complexity of the drive and the low repetition rate of duty cycles, i.e. low productivity. The indicated drawback is the result of using separate engines for gripping and turning mechanisms, as well as the use of a low-speed hydraulic drive. The disadvantage is especially noticeable when aggregating the device with automatic machines in high-performance lines.

It is also known a device of the "hand" type for transferring products, made in the form of a combined mechanism containing a transmission mechanism with drive and output links and an actuator with drive and output links, the last of which are equipped with jaws for gripping the products, and a drive (RF patent No. 2232672 , published in BIPM, 2004. - No. 20 - prototype). This device is a tool for the same purpose as the invention.

The main disadvantage of the prototype is the low accuracy and performance. The disadvantage is caused by an increased number of kinematic pairs (there are 11 to 6 lower and 5 higher pairs). The gaps in the hinges and joints of the links do not increase the accuracy and reliability of operations during the operations of "gripping the product", moving the product from position to position and "giving the product", since the gaps in the kinematic pairs lead to errors in the position and movement of the links.

The objective of the present invention is to improve the accuracy and performance.

The solution to this problem is achieved by the fact that in a combined mechanism with a complex movement of the output links, containing a transmission mechanism with a leading cam and an output link - a gear connected by a pusher in the form of a rack, an actuator with a leading and output links, the last of which are equipped with jaws for gripping products, and the output link of the transmission mechanism and the leading link of the actuator are made with the possibility of reciprocating motion, and the drive, the centers of the reciprocating the movements of the output link of the transmission mechanism and the leading link of the actuator are combined, and both links are rigidly connected to each other, while the reciprocating motion of the leading link of the actuator corresponds to the dependence

where γ is the total angle of the leading link of the actuator;

h is the stroke of the push rod of the transmission mechanism, h = r _max -r _min ;

r _max , r _min - respectively, the maximum and minimum radius-vectors of the cam gear;

d is the diameter of the pitch circle of the gear gear.

The values of the parameters h and d of the transmission mechanism satisfy the condition

The inventive mechanism differs from the prototype by the combination of structural elements and the nature of the relationship between them, which simplifies the design, improves the accuracy of work and productivity. The mechanism satisfies the first condition for operability determined by the Chebyshev formula:

W = 3 · n-2p ₅ -p ₄ = 3 · 4-2 · 4-3 = 1,

where W is the degree of mobility of the mechanism, W = 1;

n is the number of movable links: cam, pusher, gear (in tight connection with the leading link of the actuator), the output link of the actuator, n = 4;

p ₅ is the number of lower kinematic pairs (excluding passive communication, i.e., communication of the leading link of the actuator with one of the output links), p ₅ = 4,

p ₄ - the number of higher kinematic pairs (mates: cam-pusher, pusher-gear, output link-shaped groove of the copier), p ₄ = 3.

The combination of the center of the rotational motion of the leading link of the actuator with the center of the rotational motion of the output link of the transmission mechanism with a rigid connection between the two links together made it possible to exclude one higher and one lower kinematic pair from the kinematic chain of the proposed combined mechanism. In the proposed kinematic diagram of the mechanism, the following kinematic pairs are absent: gear mating with the driving element of the actuator, articulated connection of the driving element of the actuator with the rack. The decrease in the number of kinematic pairs helps to reduce the energy consumption for friction of interacting surfaces, reduce wear in friction pairs, reduce off-cycle downtime, increase the accuracy of work and productivity. The efficiency of the mechanism with a reduced number of kinematic pairs is confirmed by the formula (1).

, угол γ составляет 180°. Если h=π·d, ведущее звено делает полный оборот.Formula (2) determines the ratio of the lengths of the links of the transmission mechanism, at which the sweep angle of the leading link of the actuator carrying the output links with jaws for the products does not exceed 180 °. Provided when

, the angle γ is 180 °. If h = π · d, the leading link makes a complete revolution.

The proposed mechanism is illustrated in the drawing, which shows its kinematic diagram.

The combined mechanism with a complex movement of the output links contains a gear 1, an actuator 2 with jaws 3 for gripping products and a drive, the latter is not shown in the drawing.

The mechanism 1 is made in the form of a cam-gear mechanism, containing a leading link-cam 4, rigidly mounted on the drive shaft, a pusher-gear rack 5 mounted in a fixed guide and coupled to the cam working profile by means of a roller 6 mounted on the end of the rack, an output link gear 7, pivotally connected to the strut axle 8 and mating with said gear rack.

The mechanism 2 is made in the form of a lever-cam mechanism containing the driving link 9 in the form of a rotary rod, the swing center of which is aligned with the center of the rotary movement of the gear 7, the output links 10 and 11, pivotally connected to the rotary rod by means of the finger 12, and a stationary cam-copier 13 with curly grooves 14 and 15 for interfacing with output links. The pivot rod 9 is rigidly connected with gear 7, pin 12 is fixed at the end of the rod, rollers 16 and 17 are mounted at the free ends of output links 10 and 11 to interact with curly grooves 14 and 15 in the copier 13, respectively.

Sponges 3 are made in the form of the transmitted products, they are fixed on the output links 10 and 11 rigidly, but detachably. This shape of the jaws ensures their contact with the product over most of its perimeter. The result is a reliable retention ("grip") of the product when transferring the latter from one position to another. Detachable attachment of the jaws on the output links allows you to quickly change the jaws when changing the mechanism to transfer products of a different shape.

Sponges imitate the movement of the output links, while occupying the "unclenched" or "squeezed" position. At the boundaries of the direct (working) and reverse (idle) strokes of the output links of the sponge, they occupy a “relaxed” position. One of the boundaries of the moves of the output links corresponds to the position of "gripping the product", the other to the position of "issuing the product." The law of movement of the output links 10 and 11 in the intervals of the moves is generated by the cam 4 and the curly grooves 14 and 15 of the copier 13. The sections of the profile of the cam 4, which correspond to the boundaries of the moves of the pusher-rack 5, have constant radius vectors. This ensures that the output links of a certain duration stay with the jaws open.

The combined mechanism with a complex movement of the output links works as follows.

When the drive is operating, the rotation of the cam 4 is converted by means of the rack 5, gear 7 and the pivot rod 9 into the complex movement of the output links 10 and 11 with jaws 3 for gripping the products. In the “grip of the product” position, the product — the object of manipulation — is fed into the open lips. During the working stroke, the rollers 16 and 17, interacting with the curly grooves 14 and 15 of the copier 13, form the movement of the output links 10 and 11 relative to the pivot rod 9, as a result of which the jaws provide a “grip” and holding of the transferred product. Upon reaching the position of "issue of the product" (the boundaries of the stroke), the jaws are unclenched and cease to hold the object of manipulation, which is displayed from the device. At idle, the sponges also occupy a compressed position, since the rollers of the output links interact with the same curly grooves in the copier body as during the working stroke. Subsequent work cycles are performed in a similar manner.

The performance of the proposed combined mechanism with a complex movement of the output links depends on the mass of the transmitted products and the laws of motion of the output links of the transmission and actuating mechanisms.

Claims (2)

1. A combined mechanism with a complex movement of the output links, comprising a transmission mechanism with a drive cam and an output gear link connected by a pusher in the form of a rack, an actuator with a drive and output links, the latter of which are equipped with jaws for gripping the products, and the output link of the transmission the mechanism and the driving link of the actuator are made with the possibility of reciprocating motion, and a drive, characterized in that the centers of the reciprocating motion of the output link the transfer mechanism and the driving link of the actuator are combined, and both links are rigidly interconnected, while the reciprocating movement of the driving link of the actuator corresponds to the dependence

, where γ is the total angle of the leading link of the actuator, h is the stroke of the push rod of the transmission mechanism, h = r _max -r _min , r _max -r _min - respectively, the maximum and minimum radius vectors of the cam gear, d is the diameter of the pitch circle of the gear gear. 2. The mechanism according to claim 1, characterized in that the values of the parameters h and d of the transmission mechanism satisfy the condition