US 4,377,953 A · Indexing apparatus

Abstract

An indexing apparatus (10) is disclosed which is designed for use with various types of work transfer equipment and is operative to provide smooth rapid jerk-free acceleration and deceleration whereby workpieces may be smoothly and rapidly transferred between operating stations. The indexing apparatus (10) includes suitably arranged cams (90, 90', 106, 124, 130, 132, 150, 162, 180) and cam followers (38, 52, 114, 116, 166, 168, 174) which operate to convert a driving input motion which is typically rotary in nature to a desired output motion which may be either linear or rotary but which is characterized by substantially jerk-free, smooth acceleration and deceleration at the beginning and end of the respective indexing movements. In one embodiment the apparatus comprises a crank arm (22) having cam followers (38, 52) provided thereon which control pivotal movement of transfer arm (58) which is in turn connected to a linearly reciprocable apparatus which may include a work supporting surface for example. In another embodiment cam followers (114, 116) provided on a rotating crank (112) arm are directly engageable with camming surfaces ( 124, 130, 132) provided on a reciprocable work supporting surface. In yet another embodiment, the cam surfaces (150, 162, 180) are secured on the under surface (144) of a rotatable indexing table (140) and the apparatus is adapted to sequentially index a workpiece supported thereon through a plurality of work stations.

Claims37

Dependent claims

In a modified harmonic motion indexing apparatus having drive means including a rotatable output shaft operatively connected to transfer apparatus between first and second positions, an improved drive system comprising:

a crank arm secured to said output shaft and adapted to be rotatably driven thereby;
cam follower means secured to said crank arm;
transfer means movable from a first position to a second position, said transfer means including a camming plate having a camming surface groove provided thereon adapted to receive said cam follower means and to cooperate therewith to move said transfer means from said first position to said second position,
said camming surface groove including a dwell portion at one end thereof and an acceleration portion, said acceleration portion having a contour such that movement of said cam follower from said dwell portion into said acceleration portion in response to rotation of said crank arm will operate to smoothly accelerate said transfer means from a stationary position whereby jerk is substantially eliminated;
and
a second camming surface groove adapted to receive said cam follower means and to cooperate therewith to decelerate said transfer means as said transfer means is moved into said second position, said second camming surface groove including a deceleration portion and a dwell portion, said deceleration portion having a contour merging with said dwell portion such that as said cam follower means moves from said deceleration portion into said dwell portion the first and second derivatives of the velocity of said transfer means with respect to time are substantially equal to zero when said velocity is equal to zero whereby jerk is substantially eliminated.

3 more elements

In an indexing apparatus adapted for use to advance workpieces supported on movable means into and out of operation performing work stations, an improved drive assembly therefor comprising:

drive means having an output shaft adapted to be rotationally driven;
a crank arm secured to said output shaft, said output shaft being operative to rotationally drive said crank arm;
driven means operatively associated with said crank arm and adapted to be driven thereby;
cam means provided on one of said crank arm and said driven means and cam follower means secured to the other of said crank arm and said driven means, said cam means having a first portion contoured to cooperate with said cam follower means to provide a dwell period and a second portion comprising a groove being generally arcuate in contour and having a radius of curvature which increases at an increasing rate as distance from said first portion increases whereby said groove cooperates with said cam follower means to smoothly accelerate said driven means in response to substantially constant velocity rotation of said crank arm in a manner such that the first derivative of acceleration with respect to time increases gradually so as to avoid subjecting said indexing apparatus to any substantial jerk.

1 more element

In an indexing apparatus for use in transferring a workpiece into and out of a work station, an improved drive assembly comprising:

a reversible gear motor drive means having a rotating output shaft;
a crank arm having one end secured to said output shaft and adapted to be driven thereby;
a first cam follower secured adjacent the other end of said crank arm;
a second cam follower secured to said crank arm intermediate the ends thereof;
a transfer arm having one end pivotably secured to said indexing apparatus and being reciprocably movable between first and second positions;
a first pair of cam plates secured to said transfer arm intermediate the ends thereof, each of said cam plates having an arcuately shaped camming surface groove machined therein adapted to receive said second cam follower;
a pair of elongated members secured in spaced relationship adjacent the other end of said transfer arm and defining a substantially straight camming surface groove therebetween adapted to receive said first cam follower;
said second cam follower cooperating with one of said arcuately shaped camming surface grooves to accelerate said transfer arm in response to substantially constant velocity rotation of said output shaft in such a manner that the first derivative of acceleration with respect to time is relatively small during initial movement of said transfer arm whereby the jerk to which said indexing apparatus may be subjected to during acceleration is substantially eliminated,
said first cam follower cooperating with said straight camming surface groove to drive said transfer arm as said second cam follower moves out of said one of said arcuately shaped camming surface groove and into the other thereof.

6 more elements

Dependencies are inferred from the claim text.

Indexing apparatus

Life of this patent

Indexing apparatus

Life of this patent

Abstract

Claims37