Measuring and testing – Dynamometers – Responsive to force
Patent
1982-10-04
1985-02-19
Stouffer, Richard T.
Measuring and testing
Dynamometers
Responsive to force
172 7, 172430, A01B 63112
Patent
active
044997752
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a tractor draft sensing apparatus which forms part of a tractor draft control system.
It is known to provide a tractor draft control system which includes electrical circuitary which receives a signal from a draft force sensing unit indicative of the draft force being applied to the draft links of the tractor, compares this signal with a signal set by the operator and indicative of the required draft setting, and produces an output signal from this comparison which is used to regulate the height of the draft links so that the tractor works with the implement operating as near as possible to the required draft set by the operator.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an improved form of tractor draft sensing apparatus which enables the draft forces experienced by the draft links to be accurately relayed to the electrical circuitary of the draft control system.
According to the present invention there is provided a tractor draft sensing apparatus comprising a shaft supported at laterally spaced locations on a tractor and carrying at locations outboard of the shaft supports a pair of lower draft links so that the imposition of a draft force on the links bends the shaft, the system being characterised by the provision of a sensing unit positioned outboard of each draft link to monitor the deflection of either a portion of the shaft located outboard of the link or an axial extension of the shaft located outboard of the link to provide signals indicative of the draft force being imposed on each draft link.
As will be appreciated, the facility to separately measure the draft force of each link enables more accurate control of implements in certain conditions when the draft force imposed on the links is not equal. Also by positioning the sensing units outboard of the draft links a tractor originally designed for the use of a mechanical draft control system can be easily adapted for the use of electrical sensing units. In a tractor in which the draft links are raised by external piston and cylinder assemblies whose lower ends are secured to the tractor at locations outboard of the draft links and in alignment with the longitudinal axis of the shaft, the present invention can be realised by connecting the lower ends of the cylinders with the tractor by hollow pins through which the shaft (or an extension thereof) extends, each sensing unit being located outboard of the associated hollow pin and the clearance between the hollow pin and the shaft (or its extension) allowing the shaft (or its extension) unrestricted freedom to deflect in response to draft forces within the designed operating range of the tractor.
In such an arrangement each sensing unit can be adustably mounted on a support member carried by one end of the associated hollow cylinder mounting pin. The support member also preferably carries a protective cover which protects the sensing unit from blows and contamination by foreign matter.
Preferably the sensing units monitor the deflection of shaft extensions which are of tapering form, the cross-sectional area of the extensions reducing with increasing distance from the draft links.
Preferably the sensing units are of the electrical variable inductance type.
Preferably the or each sensing unit is adjustably mounted on the tractor for easy adjustment towards and away from the centre line of the shaft (or its extension) during the zeroing or setting up of the system.
DESCRIPTION OF THE DRAWINGS
One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a diagramatic perspective view of the rear implement hitch of a tractor embodying the present invention;
FIG. 2 is a plan view; partly in section, of part of the hitch of FIG. 1;
FIG. 3 shows the left-hand part of FIG. 2 on a larger scale;
FIG. 4 is an end view in the direction of Arrow A of FIG. 3;
FIG. 5 is a section of the line B--B of FIG. 4, and
FIG. 6 is a section on the
REFERENCES:
patent: 3342274 (1967-09-01), Wridt, Jr.
patent: 3888315 (1975-06-01), Elfes et al.
patent: 4173259 (1979-11-01), Heckenkamp
patent: 4271910 (1981-06-01), Schafer
Massey-Ferguson Services N.V.
Stouffer Richard T.
Thompson John C.
LandOfFree
Tractor draft sensing apparatus with sensing unit positioned out does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tractor draft sensing apparatus with sensing unit positioned out, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tractor draft sensing apparatus with sensing unit positioned out will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-606782