Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Reexamination Certificate
1999-11-29
2001-08-21
Noori, Max (Department: 2855)
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
C073S840000
Reexamination Certificate
active
06276216
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the priority of German Patent Application Serial No. 298 22 269.8, filed Dec. 16, 1998.
BACKGROUND OF THE INVENTION
The present invention relates, in general, to an apparatus for measuring a tensile force.
It is generally known to use such an apparatus, also called “force gage”, to measure a tensile force for use in a pneumatic device. Conventional force gages typically include a pair of longitudinal arms in spaced-apart parallel disposition, and a pair of transverse arms in spaced-apart parallel disposition and hingedly interconnecting the longitudinal arms. One of the longitudinal arms is acted upon by a tensile force and moved thereby in the direction of the tensile force, whereby both longitudinal arms are oriented in a direction parallel to the tensile force. The other longitudinal arm is secured at its upper end, for example, to a traction means. A probe is positioned between the transverse arms and has a casing securely fixed to one of the longitudinal arms for generating a pneumatic pressure signal commensurate with the tensile force. Projecting out of the casing of the probe is a pressure bolt which is acted upon in dependence on the tensile force by a transverse arm which is securely fixed to the downwardly moving longitudinal arm.
The pneumatic lifting device may, for example, be a hoist or a control mechanism for tensile stress in a take-up reel. Examples of probes include a bulk modulus or a precision pressure controller.
As a consequence of their design, conventional force gages of this type can be loaded only to a certain limit value and thus yield a limit control pressure that is proportional to the limit value. For this reason, the practical use of conventional force gages is very narrow so that hoist manufacturers are forced to store an array of different force gages to satisfy varying load-carrying capabilities of hoists.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide an improved apparatus for measuring a tensile force, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved force gage which can be used for hoists with different load-carrying capabilities.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing a parallelogram linkage having a pair of longitudinal arms in spaced-apart parallel disposition, and a pair of transverse arms in spaced-apart parallel disposition and hingedly interconnecting the longitudinal arms, with a first one of the longitudinal arms being acted upon by a tensile force and movable by the tensile force in the direction of the tensile force, whereby the pair of longitudinal arms is oriented in a direction parallel to the tensile force; a probe, positioned between the transverse arms and securely fixed to a second one of the longitudinal arms, for generating a pneumatic pressure signal commensurate with the tensile force, with the probe having a casing and a sensing element which projects out of the casing and is acted upon in dependence on the tensile force by a force-applying structure which may be either the first longitudinal arm or one of the transverse arms; a first elastic element connected with at least two members selected from the group consisting of the pair of longitudinal arms and the pair of transverse arms, such that the movement of the first longitudinal arm in response to the tensile force is opposed by an elastic force applied by the first elastic element; and a second elastic element, with the sensing element connected in series with the second elastic element and supported by the force-applying structure.
Through the provision of two such elastic elements, the effective tensile force is split in two components, with a first component of the tensile force to be measured being supported by the probe, and with a second component being supported directly by the parallelogram linkage. The force gage can be so designed that only actions applied by the tensile force impact the probe, whereas potentially encountered side forces and/or tilting moments have no influence on the probe. Overall, the force gage operates free of reactive forces.
The tensile force may, for example, be split in such a manner that only half of the tensile force acts on the probe so that the maximum applicable load of the force gage can be doubled.
Suitably, each of the first elastic element and the second elastic element is a compression spring, e.g. a disk spring, thereby realizing a compact force gage.
According to another feature of the present invention, there is provided a longitudinal beam which extends transversely to and is securely fixed to one of the transverse arms in a zone within the parallelogram linkage in opposite disposition to the one longitudinal arm that is acted upon by the tensile force, with the first elastic element being supported between this longitudinal arm and the longitudinal beam. In order to best suit the force gage to different hoists, the effective component of the tensile force acting on the probe is controllable by providing an abutment for supporting the first elastic element, with the abutment being detachably securable to the longitudinal beam for displacement in a longitudinal direction.
According to still another feature of the present invention, there is provided a screw which attaches to the one longitudinal arm that is acted upon by the tensile force, with the screw having two stops for limiting a lateral or cross movement of the longitudinal beam with respect to the vertical center plane of the parallelogram, so as to protect the probe against overload. This simple feature prevents, on the one hand, a detachment of the springs when dynamic forces are encountered at the force gage, and, on the other hand, an overload of the probe when the probe is acted upon by excessive tensile forces.
REFERENCES:
patent: 4240289 (1980-12-01), Saner
patent: 4270384 (1981-06-01), Saner et al.
patent: 4305300 (1981-12-01), Petersen et al.
patent: 4338825 (1982-07-01), Amlani et al.
patent: 5340951 (1980-12-01), Hungerbuhler et al.
patent: 87 11 385 U1 (1989-01-01), None
patent: 41 32 108 A1 (1993-04-01), None
patent: 43 05 914 C1 (1995-01-01), None
patent: 44 15 518 A (1995-11-01), None
Bittenbinder Wolfgang
Kuhn Robert
Feiereisen Henry M.
Mannesmann AG
Noori Max
LandOfFree
Pneumatic lifting device with integrated apparatus for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pneumatic lifting device with integrated apparatus for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pneumatic lifting device with integrated apparatus for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541072