Replaceable head multi-spindle fastening apparatus

#This invention relates to a multi-spindle fastening apparatus having a fastening head which is used for performing simultaneous fastening operations to a workpiece having plural portions to be fastened, and is more particularly directed to such an apparatus having plural replaceable heads wherein a selected one of the plural heads is replaceable with another in compliance with a change in kind or type of workpiece.

#An apparatus of this kind has been known wherein a head is detachably provided on a machine base so that the head can be manually detached therefrom and/or replaced with another as an occasion demands. Further, another apparatus is known wherein plural heads are fixedly disposed on a machine base and the workpiece is supplied to one of the plural working stations below a corresponding one of the heads. However, the former machine has the disadvantage that it is troublesome to replace the heads, and the latter machine has the disadvantage that it is necessary for each head to have an independent working station supplied with the respective workpiece of a different kind to be worked on by that particular head. Consequently, a large space for installation of those stations is required.

#It is an object of the present invention to provide a multi-spindle fastening apparatus having a plurality of heads which can easily be replaced as the occasion demands.

#The above and other objects and the intended advantages of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

#FIG. 1 is a top plan view, partially omitted, of one embodiment of the present invention;

#FIG. 2 is a partial sectional side view;

#One embodying example of this invention will be explained with reference to the accompanying drawings:

#Referring to the drawings, a working station 2, is installed in front of a lower portion of a supporting column 1. A pair of upper and lower annular rails 3 are provided around an upper portion of the supporting column 1. Plural multi-spindle fastening heads 4, that is four such heads for instance, are disposed and supported on the annular rails 3, 3 through respective frame bases 5 and are movably circularly therealong. A portion of both of the annular rails 3, 3 are constructed by movable rails 3a, 3a which are movable upwards and downwards. The movable rails 3a, 3a are positioned at the front of the support column 1 so that any desired one of the plural multi-spindle fastening heads 4 may be selected and lowered to be positioned at the working station 2 by a downwards movement of the movable rails 3a, 3a. The desired head 4 is moved to be positioned on the movable rails 3a, 3a by an index means 6 provided on a top portion of the supporting column 1.

#More in detail, the movable rails 3a, 3a are attached, as shown clearly in FIG. 2, to an elevating base 8 provided along a front surface of the supporting column 1. They are arranged to be movable upwards and downwards by an elevating cylinder 7 together with the elevating base 8. The index means 6 comprises, as shown clearly in FIGS. 1 and 2, a Geneva mechanism 10 composed of a Geneva pin 1Oa to be driven by an electric motor 9 and a Geneva gear 10b engaged therewith. An index arm 11 is connected to the Geneva gear 10b and carries a cylinder 12 having an engaging pin 14. The pin 14 is arranged to be mounted removably in a pin opening 13 made in a upper surface of each frame base 5. A proper head 4 corresponding to the kind of workpiece a supplied to the working station 2, is selected from the heads 4 and is positioned on the movable rails 3a, 3a by the index arm 11 being, first, turned through the Geneva mechanism 10 to be positioned just over the frame base 5 having the multi-spindle fastening head 4 corresponding to the workpiece a. Then the engaging pin 14 is inserted into the pin opening 13 of the frame base 5 of the desired head 4 by the cylinder 12. Under this engaging condition, the index arm 11 is turned back to the original position, so that the head 4 thus selected is positioned on the movable rails 3a, 3a.