Retrofit measuring device for a hay baler

Retrofittable hay bale measuring apparatus measures the size of the hay bale being formed, and indicates the size of the bale being formed to a control and display unit. The baler operator sets the desired hay bale size and monitors the baler operation on the display. A contact wheel, which contacts the hay bale and rotates as the bale is being formed, is rotationally attached to a measuring wheel. Alternatively, the contact wheel may itself comprise the measuring wheel. The rotation of the measuring wheel is monitored by a rotation detector which generates a hay bale measuring signal, and sends it to the control and display unit. The control and display unit generates a signal which indicates to the baler when it is time to tie off a bale of hay, based upon the measuring signal.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to hay balers. More particularly, the present 
invention relates to a retrofittable measuring device to determine bale 
size for use in hay balers. 
2. Description of the Prior Art 
Hay balers are complicated mechanical devices designed to pick up 
previously cut hay in the field, form it into uniform bales, tie the 
bales, and drop the bales on the ground as the operator drives the hay 
baler at a reasonably uniform rate of speed. Modern hay balers are 
extremely complicated, requiring constant maintenance and adjustment to 
operate properly. One area which becomes uncalibrated particularly quickly 
are the mechanisms for measuring and forming uniform bales of hay. 
A detailed description of the structure and operation of hay balers may be 
found in many sources. For example, refer to John Deere Operator Manual 
OME81606 (BALER 468), or AGCO Hesston Form Number 700 710 200 (4655 Square 
Baler). However, a brief discussion of the measuring and tying mechanisms 
on conventional hay balers will assist in understanding the current 
invention. FIG. 1 shows a string box 10 containing several balls 12 of 
string 15. The particular string box 10 shown in FIG. 1 contains six balls 
of string. The end of one ball of string is tied to the beginning of the 
next roll until three rolls are tied together, and the beginning of the 
first roll is threaded through several eyelet's 13 and a hole 14 before 
being provided to one of the two tying mechanisms. The other three rolls 
are similarly tied together, strung through separate eyelet's 13 and the 
other hole 14, and provided to the other tying mechanism. 
FIGS. 2 and 3 show the measuring mechanism used in conventional hay balers. 
All conventional hay balers use approximately the same measuring 
mechanism, with some small changes. Measuring assembly 35 comprises trip 
arm 34, arms 36 and 38, arc 37, and stop collar 42. Star wheel 44 is 
connected to metering gear 45 via rod 46. Trip arm 34 moves into and out 
of contact with cam 22. 
The measuring mechanism starts out in the configuration shown in FIG. 2, as 
the hay bale is being formed. Star wheel 44 contacts the top surface of 
the hay bale being formed. As the hay moves past, star wheel 44 turns 
counterclockwise, turning rod or shaft 46 connected to metering gear 45. 
Metering gear 45 causes arc 37 to move upward until the shaft moves into 
trip notch 40. This allows the measuring assembly 35 to move left and 
rotate clockwise slightly, except trip arm 34, which rotates 
counterclockwise, so that end 32 moves out of contact with dog 31, and 
reset roller 33 moves out of the way of protrusion 29. Spring loaded gear 
20 begins to rotate counterclockwise. This is the configuration shown in 
FIG. 3 
Gear 20 rotates counterclockwise one revolution. As it rotates, lower 
portion 23 of reset cam 22 forces reset roller 33 to the right, rotating 
trip arm 34 clockwise. This causes the measuring assembly to rotate 
clockwise back to its original position shown in FIG. 2. Metering gear 45 
stops when it hits stop collar 42. Protrusion 29 on rim 28 moves roller 33 
slightly upward, moving end 32 of arm 34 back into position to contact dog 
31 and prevent gear 20 from rotating further. 
Chain 26 engages with gear teeth 24, and is used to drive the knotting 
mechanism shown in FIGS. 4A-4F. In some hay balers, chain 26 is replaced 
by a gear for driving the knotting mechanism. The size of the hay bales is 
controlled by loosening stop adjustment 43, moving stop collar 42, and 
retightening stop adjustment 43. This method of determining hay bale size 
is inherently imprecise, and stop collar 42 is subject to jarring and 
vibrations which cause it to move while the baler is operating. Thus, hay 
bales from a short period of baling can vary in size so much they are 
difficult to stack. 
FIGS. 4A through 4F show the bale tying process mechanically triggered by 
the rotation of gear 20. In FIG. 4A, the bale is being formed, and string 
15 is held in string disk 49 by string holder 48. It is fed from string 
box 10. String 15 feeds down from string holder 49, over billhook 52, 
through guide 51, over the top of bale. Needle 60 holds the other end of 
string 15, pulling it around under the bale. In FIG. 4B, needle 60 brings 
the end of string 15 up through guide 51 and into string disk 49. In FIG. 
4C, billhook 52 starts to rotate to the left, forming a loop of string 
around the hook. In FIG. 4D, billhook jaw 54 opens to receive the string 
as billhook 52 continues to rotate. In FIG. 4E, billhook jaw 54 closes to 
pull the knot tight, and knife 56 on knife arm 57 cuts the string. Needle 
60 withdraws, pulling string 15 in place for the next bale. In FIG. 4F the 
severed ends of the string slide out of billhook 52. 
A need remains in the art for improved retrofittable apparatus for 
measuring hay bales in hay balers. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide improved retrofittable 
apparatus for measuring hay bales in hay balers. 
A hay baler of the kind having a bale forming mechanism which wraps string 
around the bales as they are being formed and a tying mechanism for tying 
off the formed bales with the string, and further including a measuring 
and actuating device for determining when the hay bale being formed has 
reached a predetermined size and actuating the tying mechanism, has an 
improved measuring and actuating device comprising a measuring device for 
measuring the size of the hay bale as it is being formed and generating a 
measuring signal based upon the size of the bale, and an actuating device 
connected to the measuring device for actuating the tying mechanism when 
the measuring signal reaches a predetermined value. 
Generally, the bale measuring device comprises the star wheel or contact 
wheel, which contacts the hay bale and rotates as the hay bale is formed, 
a measuring wheel, coaxial to and spaced apart from the star wheel, a rod 
rigidly attaching the axes of the contact wheel and the measuring wheel so 
the contact wheel and the measuring wheel turn together, and a rotation 
detecting device for detecting the rotation of the measuring wheel and 
generating the bale measuring signal based upon the rotation of the 
measuring wheel. The rotation detecting device may also measure the 
rotation of the contact wheel directly, eliminating the need for the 
measuring wheel and rod. The rotation detecting device may detect a 
plurality of spaced apart protrusions affixed about the perimeter of the 
measuring or contact wheel, and include a beam generator for generating a 
beam of light parallel to the axis of the wheel and directed at the 
protrusions, such that the beam of light is periodically interrupted by 
the protrusions as the wheel turns, and a beam detector aligned with the 
beam generator and located on the opposite side of the protrusions from 
the light beam generator for detecting the beam of light and generating 
the string measuring signal based upon detecting the beam of light. Or, 
the measuring wheel or contact wheel may include a plurality of magnets 
placed about the periphery of the wheel. The rotation detection device 
would then detect the movement of the magnets. 
The measuring wheel and the rotation detecting device may be located within 
a sealed unit. 
The measuring and actuating device further includes means for allowing an 
operator to input and modify the predetermined value, means for allowing 
the operator to manually override the measuring and actuating device and 
tie off a bale immediately, means for providing the measuring signal to 
the operator, and bale monitoring means for monitoring when the actuating 
device actuates the tying mechanism, and maintaining a count of the number 
of times the actuating means actuates the tying mechanism, thereby 
counting the number of hay bales formed by the hay baler, and providing 
the count to the operator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 5 shows the preferred embodiment of hay bale measuring assembly 65. 
Measuring assembly 65 utilizes star wheel 44, rod 46, and measuring wheel 
45 (shown in more detail in FIGS. 2 and 3), along with rotation detection 
apparatus 85, for measuring the size of the hay bale currently being 
formed. The rotation of measuring wheel 45 is measured by rotation 
detection apparatus 85 (shown in FIGS. 7 and 10) to provide a signal 70 
related to the size of the hay bale being formed. 
Those skilled in the art will appreciate that the use of star wheel 44 as 
the contact wheel, rod 46, and metering gear 45 as the measuring wheel is 
convenient for retrofit purposes. However, these elements may be replaced 
with some other contact wheel in contact with the hay bale for turning as 
the bale is formed, coaxially attached to a measuring wheel. The star 
wheel or contact wheel may even be used as the measuring wheel, but this 
may be impractical because of the dirty environment in the hay baler. In 
this case, the measuring wheel is spaced apart from the star wheel, and 
may be sealed in a housing unit 98 along with rotation detection apparatus 
85 to keep it clean. 
Signal 70 indicates the size of the hay bale measured by measuring assembly 
65 to control and display unit 73. The baler operator sets the desired hay 
bale size via controls 75 and monitors the baler operation on display 74. 
Control and display unit 73 also generates signal 77, which indicates to 
bale former and tying mechanism 64 when it is time to tie off a bale of 
hay. In the preferred embodiment, the operator may override the control 
and display unit and manually generate signal 77 to tie off the bale 
immediately. This manual override could be used in case of equipment 
malfunction. 
FIG. 6 shows measuring wheel 45 for use in measuring apparatus 65. Any one 
of a variety of known methods may be used to measure the hay bale. In one 
preferred embodiment, measuring wheel 45 has a series of teeth 79 formed 
around its perimeter, and is used with an optical beam generator 82 and 
optical beam detector 86 of FIG. 7. The hay bale turns wheel 44 as it is 
being formed. As star wheel 44 turns, measuring wheel 45 turns, and teeth 
79 interrupt the beam from beam generator 82. Thus, beam detector 86 
receives a series of bursts of light, the frequency of which is related to 
how quickly measuring wheel 45 is turning. Thus, if star wheel 44 has a 
circumference of one foot, and measuring wheel 45 has ten teeth 79, each 
burst of light indicates that one tenth of a foot of the hay bale has been 
formed. In the preferred embodiment, beam detector 86 simply generates a 
burst of current on line 70 coincident with each burst of light. 
In an alternative embodiment shown in FIG. 10, measuring wheel 45 (or 
contact wheel 44) has a series of magnets (or magnetic tape or the like) 
95 attached about its perimeter. Rotation detection apparatus 85 then 
comprises means 96 for detecting the movement of the magnets. In this 
case, measuring wheel 45 may simply comprise the end of rod 46. 
FIG. 8 shows how the tying mechanism as shown in FIGS. 4A-E is triggered in 
the present invention. Conventional measuring assembly 35 (comprising trip 
arm 34, arms 36 and 38, arc 37, and stop collar 42) is partially or 
entirely removed. Trip arm 34 is replaced by a mechanical arm 88, capable 
of moving down or pivoting out of the way of dog 31. The device 89 for 
moving arm 88 is triggered by signal 77 from control and display module 
73. In the preferred embodiment, device 89 comprises a solenoid for using 
electricity to move arm 88. Arm 88 is biased toward dog 31, so that arm 88 
moves back into position in time to prevent gear 20 from rotating more 
than once. As gear 20 rotates, it triggers the tying mechanism as 
described above and shown in FIGS. 4A-E. If desired, trip arm 34 could be 
left in place and used as mechanical arm 88. 
FIG. 9 shows an example of a control and display module 73 for use with 
measuring apparatus 65 of FIG. 5. The baler operator sets the desired hay 
bale size using controls 75. Control and display module 73 counts the 
bursts of voltage on line 70, and computes the size of the hay bale 
measured by measuring assembly 65 since the last bale was tied off. When 
the current hay bale reaches its desired size, signal 77 is generated to 
trigger the tying mechanism. Manual override button 93 is used to manually 
send signal 77 to tying mechanism 64, causing tying mechanism 64 to tie 
off the bale right away. 
Displays 74 in the preferred embodiment include the desired bale size, the 
size of the hay bale measured by measuring assembly 65 for the current 
bale being formed, and a count of the number of bales already formed. 
While the exemplary preferred embodiments of the present invention are 
described herein with particularity, those skilled in the art will 
appreciate various changes, additions, and applications other than those 
specifically mentioned, which are within the spirit of this invention.