Patent Application
20200096029
This invention relates to a quick release lock turnbuckle, and specifically to a quick release lock turnbuckle in a steering linkage for a zero turning radius (“ZTR”) mower, or for a lift linkage on a mower deck.
Grass mowing machines known as zero turning radius (“ZTR”) mowers have at least one independently powered drive wheel on each side of a frame. One drive wheel may be operated in a forward direction while the other drive wheel may be stopped or operated in reverse. Many ZTR mowers have a twin stick control system. A pair of control levers or sticks may be provided side-by-side, with each lever or stick controlling one of the drive wheels. When both levers or sticks are advanced together forwardly out of their neutral position, both drive wheels rotate forwardly to cause the mower to move forward. A ZTR mower may be steered by advancing one lever or stick more than the other.
Typically, each control lever or stick on a ZTR mower may be linked to a pump arm of one of two separate hydraulic pumps, or of a dual hydraulic pump; i.e., a separate pump for each wheel. The lever or stick may be used to move a pump swash plate through a direct linkage.
The control levers or sticks on a ZTR mower may be mounted on the vehicle frame so that each has a first pivot axis allowing the lever or stick in the operating position to pivot forwardly in an arc to turn the wheel in forward, or pivot rearwardly to turn the wheel in reverse. Additionally, the operator can pivot each lever or stick to a neutral operating position, and then pivot each lever or stick outwardly in an arc to a non-operating or park position. If both levers or sticks are pivoted to neutral, the ZTR mower should be stationary, both levers or sticks should be at the same position, and both levers or sticks should align with slots so that they can pivot outwardly to park. An operator may need to make neutral adjustments to the linkages if the levers or sticks are misaligned in the neutral position, due to wear, age or loosening of components of the ZTR mower.
Neutral adjustments for levers or sticks on ZTR mowers typically require the operator to loosen a pair of tumbuckles. Tools are needed to loosen the jamnut on a tumbuckle, which connects the lever control arm to the pump control arm. Many existing tumbuckles include a secondary jamnut to lock the tumbuckle settings. The operator then must retighten the tumbuckles. The operator also may need to lift the rear of the unit off the ground to prevent the machine from moving during the adjustment.
Some mower decks also have lift arms with an adjustment tumbuckle that may be used to level the deck at the desired cutting height. These tumbuckles have jamnuts that must be loosened and then retightened with tools.
There is a need for a quick release lock tumbuckle for a steering linkage on a ZTR mower that does not require the operator to use tools. A quick release lock tumbuckle is needed that allows neutral adjustments to be performed with minimal effort. A quick release lock tumbuckle is needed that does not loosen during use. There also is a need for a quick release lock for a tumbuckle used in a mower deck linkage.
A quick release lock tumbuckle connects a first rod and a second rod of a zero turn mower steering linkage. The first and second rods are threaded into a first end and a second end of a tumbuckle with an outer multi-sided cross section. A socket having an internal passage with a multi-sided cross section is slideable over the tumbuckle to a locked position preventing rotation of the turnbuckle. The socket is slideable off the tumbuckle to an unlocked position allowing rotation of the tumbuckle to adjust how far the first rod and the second rod are threaded into the first end and the second end of the turnbuckle
In one embodiment, quick release lock tumbuckle 100 may be used on zero turning radius (“ZTR”) mower 102 shown in
Now referring to
In one embodiment, the lower end of each control lever or stick 116 may be mounted so that each lever or stick can move independently of the other. In
In one embodiment, quick release lock tumbuckle 100 may connect between two threaded rods 138, 140 of steering linkage 132. The quick release lock tumbuckle may connect the two threaded rods coaxially, at a desired end-to-end spacing. The quick release lock tumbuckle may be positioned between the two threaded rods, preferably at a location between the control lever and hydrostatic pump. More specifically, the quick release lock tumbuckle may be positioned between front ball joint 134 of control pivot 128 at the base of the control lever, and input lever 136 of the hydrostatic pump. The quick release lock tumbuckle may provide adjustability of the effective length of the steering linkage, and lock in the adjustment to prevent rotation during use from the specified length.
In one embodiment, quick release lock tumbuckle 100 may include socket 142. The socket may have internal passage 144 extending therethrough. The internal passage may have a hexagonal cross section. Alternatively, the internal passage may have a square cross section or octagonal cross section. First threaded rod 138 may be inserted into and extend through the internal passage. The first threaded rod may have one or more keyed features 146 that extend radially from its outer diameter. The keyed features may engage two sides of the internal passage and prevent the socket from rotating relative to the first threaded rod, while allowing the socket to move axially relative to the first threaded rod.
In one embodiment, socket 142 may slide over turnbuckle 156. First threaded rod 138 may be threaded into first end 164 of the tumbuckle, and second threaded rod 140 may be threaded into second or opposite end 166 of the tumbuckle. The first end of the tumbuckle may be inserted into internal passage 144 extending through socket 142. This is the locked position shown in
In one embodiment, quick release lock turnbuckle 100 may include compression spring 148 biasing the socket axially into the locked position. The compression spring may be positioned between retainer clip 150 and shoulder 152 at or near a first end of the socket. When the socket engages and locks the tumbuckle, the compression spring may prevent or minimize rotation of the tumbuckle during use, by locking in the positions of the two threaded rods.
In one embodiment, as shown in
Having described the preferred embodiments, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
