US 3089356 A
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May 14, 1963 D. P. WESTRA 3,089,356
BELT DRIVE FOR PAPER PUNCH Filed Dec. 4, 1961 36 4g INVENTOR.
fi4/V W557)? 44 50 Eta/5W '1 atent 3,089,355 Patented May 14, 1963 1 free 3,089,356 BELT DRIVE FOR PAPER PUNCH Dan P. Westra, Grand Haven, Mich, assignor to The Challenge Machinery Company, Grand Haven, MICIL, a corporation of Michigan Filed Dec. 4, 1961, Ser. No. 156,600 3 Claims. (Cl. 7724) This invention relates to drilling machines for drilling stacks of paper, and more particularly to a novel drive mechanism for such machines.
Paper drilling machines with adjustable heads have been known for quite some time. Such machines have a plurality of hollow cylindrical drills which are rapidly rotated by drive spindles mounted in laterally movable heads. The heads can be moved to change the spacing between adjacent drills as necessary for drilling paper stacks to fit various types of mechanical binders. The speed of rotation of the drills is critical in the sense that a reduction in their angular velocity below a predetermined minimum has a tendency to break or clog them. For this reason, it was previously thought necessary to rovide machines of this type with a gear drive which was usually complicated and expensive to build and maintain. It has therefore been desirable for some time to provide a machine of this type with a belt drive such as that previously used on paper drills with stationary heads. The problem, however, was that unless the tension of the belt could be made to remain constant throughout the entire range of movement of the drilling heads, the belt would tend to slip in one extreme position and cause breakage of the drills, and be overly tight in the other extreme position so as to cause excessive wear of the belt and the spindle bearings. For this reason, it was not possible to use spring-loaded tensioning rollers, because the range of movement of the heads was so great that the force of the spring would vary excessively be tween its two extreme positions in any construction of physically practicable size.
The present invention solves this problem by connecting a pair of idler rollers to the adjustable heads in such.
a manner that as the heads are moved, the idler rollers are pivoted about a pivot mounted to the frame of the machine in such a manner as to compensate for the lengthening or shortening of the belt path caused by the movement of the drill heads.
It is therefore the object of this invention to provide a belt drive for a paper drill in which the drive belt is maintained under a substantially constant tension throughout the range of adjustability of the drill heads by providing automatically compensating idler pulleys movable in conjunction with the drill heads.
This and other objects of this invention will become apparent from a perusal of the following specification, taken in connection with the accompanying drawings in which:
FIG. 1 is a plan view of the mechanism of this invention;
FIG. 2 is a front elevation of the device; and
FIG. 3 is a side elevation of the device, partly in section at lines III-I=II of FIG. 1.
Basically, the invention consists of providing a pair of idler pulleys each mounted at one end of a lever arm pivoted on the frame of the machine. The other end of the lever arm terminates in a slot which embraces a pin attached to the supporting block of the movable drill head with which the arm is associated. As the drill head is moved back and forth, the pin causes the lever arm to pivot about its pivot, and the idler wheels consequently move in a direction such as to compensate for the 2 difference in belt path length caused by the movement of the drill head.
Referring now to the drawings, the drilling machine generally shown at 10 is powered by a motor 12 supported in an adjustable mounting 14 in such a manner that it can be moved up and down in FIG. 1 by means of the adjusting knob 16. A belt 18 passes from the motor pulley 20 around idler pulley 22, movable drive pulley 24, fixed drive pulley 26, movable drive pulley 28 and idler pulley 30 back to motor pulley 20. The drive pulleys 24, 26, 28 drive drills 32, 34, 36, respectively, through spindles such as 38. The spindle 38 is mounted in an adjustable support block 40 which can be moved from left to right and vice versa in FIG. 1 by turning the adjusting knob 42. For continuously accurate verticality of the drill, the support block 40 moves back and forth on guide rods 44. A height adjustment knob 46 permits height adjustment of the drill 32 to compensate for drill length variations due to repeated sharpening or other causes. Pins 48 movable in slots 50 provide a visual indication of the height adjustment of the drill 32 and also prevent the spindle bearings from rotating within the support block 40.
As the block 40 is moved by turning the adjusting knob 42, the pin 52 moving in slot 54 causes lever arm 56 to pivot about pin 58. As a result, idler pulley 22 is swung as indicated by the arrows in FIG. 1 in a path such as to, for example, slacken the belt 18 by leftward movement (in FIG. 1) to the same degree as it is tightened by the rightward movement (in FIG. 1) of pulley 24.
An independent but similar mechanism is provided for the interaction of drive pulley 28 and idler pulley 30 when the supporting block 60' is moved by turning adjusting knob 62. It will be understood that the compensating means just described permit adjustment of the spacing between drill heads from any given minimum to many times that minimum without any appreciable change in the tension of the belt.
Operation In operation, the belt 18 is placed around all the pulleys as shown in FIG. 1 with the motor 12 in its lowermost position in FIG. 1. The setting of the knobs 42, 62 for this purpose is quite immaterial. When the belt is in place, adjusting knob 16 is turned to raise the motor 12 in FIG. 1 until the belt has reached the desired tension. The drills 32, 34, 36 are then adjusted to identical heights by adjusting knobs 46, 64, 66, and the machine is ready to operate. When the lateral spacing of the drills is to be changed for a different run of stock, it is merely necessary to turn knobs 42, 62 to the desired spacings as indicated on the scale 63. Due to the action of idler pulleys 22, 30, the tension of belt 18 remains constant during this operation.
It will be seen that this invention provides a simple and effective drive means for a paper drilling machine. Obviously, many modifications of this invention are possible, and I therefore do not desire to be limited by the embodiment shown, but only by the scope of the following claims.
1. In a motor-powered multi-spindle drive for an adjustable paper drill, the improvement comprising: drive pulley means for driving each spindle; belt means transmitting motion from said motor to said drive pulley means; and movable idler pulley means engaged by said belt means and connected to at least one of said spindles for nonresilient movement when the spacing between said spindles is varied, said movement being such that the total length of the path described by said belt about all of said pulley means remains substantially constant throughout the entire available range of spindle spacings.
2. An adjustable multi-spindle paper drill, comprising: a motor; a plurality of drill spindles; a movable support block supporting one of said spindles for linear transverse movement with respect to another of said spindles; means for moving said support block to vary the spacing between said last-named spindles; drive pulley means associated with each of said spindles for rotating them; a belt engaged with said pulleys and said motor for transmitting rotary motion from said motor to said spindles; an idler pulley engaged with said belt and connected to said support block for movement therewith in such a manner as to keep the total length of the path described by said belt substantially constant throughout the range of movement of said support block.
3. An adjustable multi-spindle paper drill, comprising: a motor; a frame; a plurality of drill spindles; a movable support block supporting one of said spindles for transverse movement with respect to another of said spindles; means for moving said support block to vary the spacing between said last-named spindles through a varying range; drive pulley means associated with each of said spindles for rotating them; a belt engaged with said pulleys and said motor for transmitting rotary motion from said motor to said spindles; an idler pulley pivotally mounted to said frame, engaged with said belt and connected to said support block for movement therewith in such a manner as to keep the total length of the path described by said belt substantially constant throughout said range.
References Cited in the file of this patent UNITED STATES PATENTS