US 5,880,410 A · Load cells with integral damping

A weighing device, comprised of at least one off-center load cell having a fixed part which is mounted on a base, a deflectable part which when loaded deflects slightly relative to said fixed part, and stress surfaces connecting the fixed part to the deflectable part, said deflectable part having an extension part securely connected and extending generally in a direction of said fixed part, said extension part opposes said fixed part but does not touch said fixed part or any other part of said weighing device except where said deflectable part is connected, and in which arrangement when load is applied on said deflectable part there will result a slight relative motion between said extension part and said fixed part opposing said deflectable part, strain gages bonded on said stressed surfaces such that when loaded, a voltage output signal is produced which is proportional to the weight of the load, and into said fixed part a cylindrical space is built, while in the opposing extension part, a piston is securely connected through a connecting rod, which the connecting rod causes said piston to move into said cylindrical space such that said piston, said connecting rod and said cylindrical space all lie on the same concentric line, said cylindrical space filled with viscous fluid covering at least said piston and said piston having a very small gap between its own lower surface and the bottom of said cylindrical space, such that when a force is applied to said load cell then said piston is caused to move within said cylindrical space toward said bottom of said cylindrical space and viscous damping is created.

A load cell device for determining the weight of a load, comprising:

a. a pair of opposing off-center load cells integrally connected to each other and forming a unitary body, the unitary body having a top end with a central opening, a central cylindrical interior chamber located between the pair of opposing off-center load cells, and a protruding bottom end, the cylindrical interior chamber defined by a flat bottom and a circumferential sidewall with an upper portion;
b. a load receiving adaptor mounted on said top end of said unitary body by connecting means and creates deflection on said pair of off-center load cells, the load receiving adaptor having a protruding bottom end extending through and covering said central opening of said top end of said unitary body;
c. at least two equally spaced apart strain gages respectively attached to a respective one of said pair of opposing off-center load cells, and lying generally on a horizontal plane for producing a voltage output proportional to the weight of said load;
d. a damping piston means having a circumferential side surface and a substantially flat lower surface;
e. the circumferential wall of said damping piston means being smaller than the circumferential wall of said interior chamber;
f. means for attaching said damping piston means to said protruding bottom end of said load receiving adaptor and suspending said damping piston means in said interior chamber, such that said circumferential side surface of said damping piston means clears said circumferential sidewall of said interior chamber, but said substantially flat lower surface of said damping piston means is positioned parallel and very close to said flat bottom wall of said interior chamber, which leaves a very narrow space between said substantially flat lower surface of said damping piston means and said flat bottom of said interior chamber;
g. a body of viscous fluid of sufficient quantity contained in said interior chamber such that at least said substantially flat lower surface of said damping piston means is submerged, so that the body of viscous fluid between said substantially flat lower surface of said damping piston means and said flat bottom of said interior chamber is compressed and creates a resistance force on said damping piston means that effectively dampens vibration on said load;
and
h. a bellows seal means mounted between said interior chamber and said load receiving adaptor and having a bottom end and a top end, the bottom end attached to said upper portion of said interior chamber, and the top end attached to a side of said central opening of said top end of said unitary body such that it seals said body of viscous fluid contained in said interior chamber.

6 more elements

A load cell device for determining the weight of a load, comprising:

a. at least two load cells integrally connected to each other and forming a unitary body, the unitary body having a first end with an opening, and an interior chamber defined by a flat bottom and a sidewall with an upper portion and located between the at least two off-center load cells;
b. a load receiving means for covering said opening of said first end of said unitary body and creates deflection on said at least two load cells;
c. at least two equally spaced apart strain gages respectively attached to said unitary body and lying on a horizontal plane for producing a voltage output proportional to the weight of said load;
d. a piston means having a side surface and a flat lower surface, the circumferential dimension of the piston means being smaller than the circumferential dimension of said interior chamber;
e. means for attaching said piston means to said load receiving means and suspending said piston means in said interior chamber, such that said side surface of said piston means clears said sidewall of said interior chamber, but said flat lower surface of said piston means is positioned parallel and very close to said flat bottom of said interior chamber, which leaves a very narrow space between said flat lower surface of said piston means and said flat bottom of said interior chamber;
f. a body of viscous fluid of sufficient quantity contained in said interior chamber such that at least said flat lower surface of said piston means is submerged, so that the body of viscous fluid between said flat lower surface of said piston means and said flat bottom of said interior chamber is compressed and creates a resistance force on said piston means that effectively dampens vibration on said load;
and
g. means for sealing said body of viscous fluid contained in said interior chamber.

5 more elements

A load cell device for determining the weight of a load, comprising:

a. a pair of opposing off-center load cells integrally connected to each other and forming a unitary body, the unitary body having a top end with a central opening, a central cylindrical interior chamber located between the pair of opposing off-center load cells, and a protruding bottom end, the cylindrical interior chamber defined by a flat bottom and a circumferential sidewall with an upper portion;
b. a load receiving adaptor mounted on said top end of said unitary body by connecting means and creates deflection on said pair of off-center load cells, the load receiving adaptor having a protruding bottom end extending through and covering said central opening of said top end of said unitary body;
c. at least two equally spaced apart strain gages respectively attached to a respective one of said pair of off-center load cells, and lying generally on a horizontal plane for producing a voltage output proportional to the weight of said object;
d. a damping piston means having a circumferential side surface, a substantially flat lower surface, an upper surface and a vertical interior narrow passage extending through the damping piston means from the upper surface to the flat lower surface;
e. the circumferential wall of said damping piston means being slightly less than the circumferential wall of said interior chamber;
f. means for attaching said damping piston means to said protruding bottom end of said load receiving adaptor and suspending said damping piston means in said interior chamber, such that said circumferential side surface of said damping piston means is very close to said circumferential sidewall of said interior chamber, but said substantially flat lower surface of said damping piston means is positioned parallel and remote from said flat bottom of said interior chamber, which leaves a large space between said substantially flat lower surface of said damping piston means and said flat bottom of said interior chamber;
g. a body of viscous fluid of sufficient quantity contained in said interior chamber such that at least said substantially flat lower surface of said damping piston means is submerged such that the body of viscous fluid can flow through said narrow passage of said damping piston means and creates a resistance force on said damping piston means that effectively dampens vibration on said load;
and
h. a bellows seal means mounted between said interior chamber and said load receiving adaptor and having a bottom end and a top end, the bottom end attached to said upper portion of said interior chamber, and the top end attached to a side of said central opening of said top end of said unitary body such that it seals said body of viscous fluid contained in said interior chamber.

6 more elements

A load cell device for determining the weight of a load, comprising:

a. at least two load cells integrally connected to each other and forming a unitary body, the unitary body having a first end with an opening and an interior chamber defined by a flat bottom and a sidewall with an upper portion and located between the at least two off-center load cells;
b. a load receiving means for covering said opening of said first end of said unitary body and creates deflection on said at least two load cells;
c. at least two equally spaced apart strain gages respectively attached to said unitary body and lying on a horizontal plane for producing a voltage output proportional to the weight of said object;
d. a piston means having a flat lower surface, a side surface, an upper surface, and a narrow passage extending through the piston means from the upper surface to the flat lower surface, the circumferential dimension of said piston means being slightly less than the circumferential dimension of said interior chamber;
e. means for attaching said piston means to said load receiving means and suspending said piston means in said interior chamber, such that said side surface of said piston means is very close to said sidewall of said interior chamber, but said flat lower surface of said piston means is positioned parallel and remote from said flat bottom of said interior chamber, which leaves a large space between said flat lower surface of said piston means and said flat bottom of said interior chamber;
f. a body of viscous fluid of sufficient quantity contained in said interior chamber such that at least said flat lower surface of said piston means is submerged such that the body of viscous fluid can flow through said narrow passage of said piston means and creates a resistance force on said piston means that effectively dampens vibration on said load;
and
g. means for sealing said body of viscous fluid contained in said interior chamber.

5 more elements