Handling: hand and hoist-line implements – Miscellaneous compound implement
Patent
1991-10-15
1993-07-20
Focarino, Margaret A.
Handling: hand and hoist-line implements
Miscellaneous compound implement
294 641, 294116, 29743, B66C 102, H05K 1304
Patent
active
052287327
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a device of the type named in the preamble.
The assembly heads used in the assembly technology for handling devices for the programmed automatic mounting of components on a workpiece, particularly to assemble electronic components (SMD components) on printed circuit boards, usually are provided with several independent axes which are driven by pilot motors in order to activate individual function units, such as grab tongs, by transmission mechanisms.
An assembly head is known from DE-PS 32 17 672 where several function units are activated by transmission mechanisms, either independently or coupled together. These function units consist of a rotary star which can be rotated 360 degrees, two pairs of tongs attached thereto, a sleeve, which can be moved longitudinally and which is guided in a central bore of the rotary star, and an ejection device which serves to eject components held by vacuum on the suction pipette, or to vacuum seal the suction pipette.
The ejection device, like the pairs of tongs and the sleeve which can be moved longitudinally, is activated by a transmission mechanism, whose movement is controlled by a cam disc. Since the ejection device is to be activated in dependence longitudinally movable sleeve's stroke position, the transmission mechanisms of the ejection device and of the sleeve are coupled.
The transmission mechanism of the ejection device, like the other transmission mechanisms, consists of different solidly designed transmission links. Due to its solid design the transmission mechanism of the ejection device constitutes a considerable part of the mass to be moved by the sleeve with every stroke movement. Since the maximum stroke frequency of the sleeve is limited by the inertial forces which occur, and which lead to harmful excitation of vibrations in the assembly head, this solid design of the transmission mechanism has a negative impact on the number of pieces which can be obtained in the production of printed circuit boards.
The task of the invention is to develop an assembly head of the type described above in such a way that by reducing the actuated mass a higher stroke frequency can be obtained, and yet a safe and trouble-free operation of the assembly head is possible.
This task is solved with the characteristics of claim 1.
Activating the ejection device by a control element acted on by a tensile load makes operation easier, simply with tensile load materials for the use as control element. This results in a considerable reduction of the mass to be actuated by the sleeve and therefore the possibility to increase the maximum stroke frequency.
According to an advantageous development of the invention, the control element is a component of the transmission mechanism which is articulated to the frame of the assembly head to activate the ejection device. In order to form a solid connection the control element is connected with a rotary lever which is actuated by a disc cam and which activates the ejection device by a push-rod, whereby the lever is rotatably connected with a stroke lever in a swivel joint, which makes the movement of the sleeve possible.
Here, it is of advantage to use, aside from the transmission mechanism, only small push-rods with a minimal stroke as well as a rotary lever, which is connected with the existing stroke lever to move the sleeve and which acts directly on the push-rods, instead of solid expansive levers which are arranged girder-like in the assembly head.
In a preferred design example the control element is designed as a steel band. This makes a flexible design of the control element possible, which also allows adaption to limited installation space.
For an advantageous space-saving arrangement of the transmission mechanism elements the control lever and the stroke lever are arranged opposite each other on either side of the sleeve, whereby the steel band is redirected in the area of the swivel bearing which houses the stroke lever.
According to an advantageous development of the invention the rotary lever is arranged pa
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patent: 3857496 (1974-12-01), Gonzales
patent: 4705311 (1987-11-01), Ragard
patent: 4753004 (1988-06-01), Fujioka
patent: 4770599 (1988-09-01), Hawkswell
patent: 4950011 (1990-08-01), Borcea et al.
patent: 5033185 (1991-07-01), Hidese
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Focarino Margaret A.
Kramer Dean J.
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