US2703707A

US2703707A - Arresting arrangement for precision balances

Info

Publication number: US2703707A
Application number: US155606A
Authority: US
Inventors: Sartorius Horst
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-04-13
Filing date: 1950-04-13
Publication date: 1955-03-08
Anticipated expiration: 1972-03-08

Description

March 8, 1955 s o us 2,703,707

ARRESTING ARRANGEMENT FOR PRECISION BALANCES Filed April 13, 1950 2 Sheets-Sheet l F: .3 I 9 /2 9 Inventor:

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March 8, 1955 SARTQRIUS 2,703,707

ARRESTING ARRANGEMENT FOR PRECISION BALANCES Filed April 15, 1950 2 Sheets-Sheet 2 In ventor".

United States Patent Office Patented Mar. 8, 1955 ARRESTING ARRANGEMENT FOR PRECISION BALANCES Horst Sartorius, Goettingen, Germany Application April 13, 1950, Serial No. 155,606 4 Claims. (Cl. 265-54) The present invention relates to an arresting arrangement for precision balances.

It is one object of the present invention to provide an arresting arrangement for precision balances which permits arresting of the beam of the balance and of suspension members supported on the beam without any stress on the bearings, and without any detrimental sliding of the knife edges on which the beam and the suspension members are supported.

It is another object of the present invention to provide arresting arms for arresting the suspension members, and a beam arrest for arresting the beam, and to provide means for moving the arresting arms at a greater speed than the beam arrest so that the suspension members are lifted 01f the beam during the arresting operation.

It is a further object of the present invention to support the arresting arms on three points permitting lateral tilting of the arresting arms whereby any stress in the bearing points is avoided.

With these objects in view, the present invention is applied to a precision balance including supporting means, a knife edge on the supporting means, a horizontal beam supported by the knife edge, and two suspension members supported on the outer ends of the beam, and mainly consists in an arresting arrangement comprising, in combination, a beam arrest mounted on the supporting means reciprocable in vertical direction and adapted to engage the beam for moving the same between an operative position seated on the knife edge to an arrested position upwardly spaced therefrom, a pair of movable arresting arms extending from the supporting means outwardly towards the suspension members having outer ends located under the suspension members and adapted to engage the suspension members from below, and inner ends located in the region of the knife edge, two first bearing means, each of the two bearing means supported by the supporting means and tiltably supporting one of the arresting arms at the inner end thereof, and two pairs of second bearing means supported by the beam arrest, each pair of second bearing means supporting one of the arresting arms at two spaced polnts located on a line extending normal to the arresting arms intermediate the ends of the associated arm so that upward movement of the beam arrest causes lifting of the beam into arrested position and upward tilting of the arresting arms about the first bearing means in vertical direction while the outer ends of the arresting arms move at a speed greater than the speed of the beam arrest and the beam resulting in lifting of the suspension members off the beam during upward movement of the beam arrest and the beam.

Preferably the bearing means are constituted by pins engaging corresponding recesses.

According to a modified embodiment of the present invention, a bridge member is provided intermediate each of the arresting arms and the beam arrest, the bridge members being supported by pins projecting from the beam arrest, and supporting the arresting arms by means of pins.

The invention will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing, in which:

Fig. 1 is a front elevation, partly in section, of a preferred embodiment of the present invention;

Fig. 2 is a plan view of the carrier arms used in the embodiment of Fig. 1;

Fig. 3 is a fragmentary sectional view taken on line 33 in Fig. 2;

Fig. 4 is a plan view of the beam arrest used in the embodiment of Fig. 1;

Fig. 5 is a fragmentary sectional view of a modified embodiment of the present invention; and

Fig. 6 is a cross-sectional view on line 6-6 in Fig. 5.

Referring now to the drawings, and more particularly to the embodiment shown in Figs. 1 to 4, on the tubular column 1 a head 3 is mounted by means of guiding members 2, the

members

1, 2 and 3 constituting the supporting means of the arrangement. A lifting bar 9 is mounted in the supporting tubular column 1 slidable in vertical direction and may be actuated by an operating member, not shown in the drawing. A stone 4 is secured to the head 3 and cooperates with a knife edge 5 which is secured to the beam 6. On the outer end of the beam 6, knife edges 7 are provided on which the suspension members 8 for the weight pans are mounted. The suspension members 8 are provided with stones 8' which rest on the knife edges 7.

A beam arrest 11 is secured to the lifting bar 9 by means of screws 10 and is guided on the guiding members 2 which pass through bores 14 in the beam arrest 11. To the ends of beam arrest 11, two upwardly extending pins 13 are secured which are adapted to cooperate with the beam 6. Above the beam arrest 11, two arresting arms 15 are provided, each of the arresting arms 15 being formed with three spaced

recesses

16, 18 and 19 and having two forked arms 15:: and 15b The forked arm 15b is not shown in the left portion of Fig. 1. Two first vertical pins 17 having ball-shaped upper ends are secured to the head 3 and project into the cup-shaped recesses 16, constituting first bearing means permitting tilting of the arresting arms 15 in vertical and transverse directions. The vertical pins 12 are secured to the beam arrest 11 and engage the

recesses

18, 19 in the arresting arms 15, located at spaced points on a line extending normal to the arresting arms. The recess 18 has a fiat bearing face, while recess 19 has a V-shaped bearing face. The pins 12 and

recesses

18, 19 constitute the second bearing means for the arresting arms 15. Secured to the outer ends of the forked arms 15a, 15b of the arresting arms 15 are pins 20 bers 8. The suspension members 8 extend transversely across the forked arms 15a, 15b of the arresting arms 15 so that each of the knife edges 7 is located between two pins 20. A spring 21 is attached to member 22 which is secured to the head 3 and urges the arresting arms 15 downwardly into engagement with the pins 12 and 17.

The arresting arrangement described above operates in the following manner: By operation of an eccentric means, not shown, the lifting bar 9, and thereby the beam arrest 11, are upwardly moved in vertical direction. The beam arrest 6 is moved to an arresting position in which the pins 13 engage the beam 6, and lift the same to an arrested position spacing the knife edge 5 from hearing stone 4. The arresting arms 15 are vertically tilted by the pins 12 about the bearing means 16, 17, so that the pins 20 on the outer ends of the forked arms 15a, 15b of the arresting arms 15 engage and arrest the suspension members 8 which are lifted off the knife edges 7. The bearing points 16, 17 permit tilting of the arresting arms in all directions, bearing points 19 serve as centering means, and bearing points 18 are only capable of transmitting vertical forces. Thereby, tilting and sliding of the arresting arms with respect to the beam arrest are avoided. The outer ends and pins 20 of the arresting arms 15 move faster than the

points

18, 19 of the arresting arms, since the radius 17, 20 is longer than the radius 17, 12. On the other hand, the pins 13 move at the same speed as the beam arrest 11, and since the pins 12 are secured to the same beam arrest 11,

pins

12 and 13 move at the same speed so that pins 20 on the ends of the arresting arms 15 move faster than pins 13.

The beam 6 being arrested by the pins 13, movement of the beam arrest 11 in upward direction will cause first engagement of the pins 20 with the suspension members 8 and then engagement of the pins 13 with the beam 6.

which cooperate with the suspension mem- The spring 21 is provided for returning the arresting arms 15 to normal weighing position, which operation, however, may be effected by other means, for instance by gravity. In turning back into the position of normal use, the lifting bar 9 is moved downwardly, and thus the arresting arms 15 swing down again about the bearings 16, 17. Only after the beam 6 has been seated on the head 3, the suspension members 8 are placed on knife-edges 7. The three-point support of the arresting arms 15 permits engagement of knife-edges 7 with the suspension members 8 during an exactly vertical movement.

In the embodiment shown in Figs. and 6, the pins 12 are not secured to the beam arrest 11, but to bridge members 23. Each bridge member 23 is provided at its bottom face with two recessed bearing faces 1% and 19c, bearing face 1912 having a conical shape, while bearing face 19c is a V-shaped groove. Pins 12a secured to the beam arrest 11 engage the recesses in the bottom faces of the bridge members 23, while the pins 12 engage with their pointed ends recesses in the bottom face of the arresting arms 15 shaped similar to the corresponding recesses in the bridge members. Pins 12a and 12 are vertically aligned so as to form an articulated support.

The above-described modified embodiment of the present invention operates in the following manner: When the beam arrest 11 is lifted, the pins 12a engage the bridge members which transmit the force through the pins 12 to the carrier arms 15. When the beam arrest 11 is lifted, the bridge members 23 tilt a little from their original position.

While the invention has been illustrated and described as embodied in an arresting arrangement for a precision balance according to which arresting arms for arresting suspension members are mounted on three points, it is not intended to be limited to the details shown, since various structural changes may be made without departing from the spirit of the present invention.

What is claimed as new, and desired to be secured by Letters Patent is:

1. In a balance including supporting means, a knife edge on said supporting means, a horizontal beam supported by said knife edge, and two suspension members supported on the ends of said beam and adapted to be lifted off said beam, an arresting arrangement, comprising in combination, a beam arrest mounted on said supporting means reciprocable in vertical direction and adapted to engage said beam for moving the same between an operative position seated on said knife edge to an arrested position upwardly spaced therefrom; a pair of movable arresting arms extending from said supporting means outwardly towards said suspension members having outer ends located under said suspension members and adapted to engage said suspension members from below, and inner ends located in the region of said knife edge; two first bearing means, each of said two bearing means supported by said supporting means and supporting one of said arresting arms at the inner end thereof; and two pairs of second bearing means supported by said beam arrest, each pair of second bearing means supporting one of said arresting arms at two spaced points located on a line extending normal to said arresting arms intermediate the ends of the associated arm so that upward movement of said beam arrest causes lifting of said beam into arrested position and upward tilting of said arresting arms about said first bearing means in vertical direction while said outer ends of said arresting arms move at a speed greater than the speed of said beam arrest and said beam, resulting in lifting of said suspension members ofi said beam during upward movement of said beam arrest and said beam.

2. In a balance including supporting means, a knife edge on said supporting means, a horizontal beam supported by said knife edge, and two suspension members supported on the ends of said beam and adapted to be lifted off said beam, an arresting arrangement, comprising in combination, a beam arrest mounted on said supporting means reciprocable in vertical direction and adapted to engage said beam for moving the same between an operative position seated on said knife edge to an arrested position upwardly spaced therefrom; a pair of movable arresting arms extending from said supporting means outwardly towards said suspension members having outer ends located under said suspension members and adapted to engage said suspension mem bers from below, and inner ends located in the region of said knife edge, each of said arresting arms being formed with three spaced recesses on the lower face thereof; two first vertical pins, each of said two vertical pins secured at its lower end to said supporting means and having a rounded upper end engaging a cup-shaped recess located at the inner end of one of said arresting arms tiltably supporting said arresting arm; and two pairs of second vertical pins, each pin secured at the lower end thereof to said beam arrest and having a pointed upper end engaging a corresponding recess in one of said arresting arms, each pair of second pins supporting one of said arresting arms at two spaced points located on a line extending normal to said arresting arms intermediate the ends of the associated arm so that upward movement of said beam arrest causes lifting of said beam into arrested position and tilting of said arresting arms about said first vertical pins in vertical direction while said outer ends of said arresting arms move at a speed greater than the speed of said beam arrest and said beam, resulting in lifting of said suspension members off said beam during upward movement of said beam arrest and said beam.

3. In a balance including supporting means, a knife edge on said supporting means, a horizontal beam supported by said knife edge, and two suspension members supported on the ends of said beam and adapted to be lifted off said beam, an arresting arrangement, comprising in combination, a beam arrest mounted on said supporting means reciprocable in vertical direction; four upwardly extending pins secured at the lower ends thereof to said beam arrest movably therewith and adapted to engage said beam for moving the same between an operative position seated on said knife edge to an arrested position upwardly spaced therefrom; a pair of movable arresting arms extending from said supporting means outwardly towards said suspension members having outer ends located under said suspension members and adapted to engage said suspension members from below, and inner ends located in the region of said knife edge, each of said arresting arms being formed with three spaced recesses on the lower face thereof; two first vertical pins, each of said two vertical pins secured at its lower end to said supporting means and having a rounded upper end engaging a cup-shaped recess located at the inner end of one of said arresting arms tiltably supporting said arresting arm; two pairs of second vertical pins. each second pin secured at the lower end thereof to said beam arrest and having a pointed upper end engaging a corresponding recess in one of said arresting arms, each pair of second pins supporting one of said arresting arms at two spaced points located on a line extending normal to said arresting arms intermediate the ends of the associated arm, the recess located at one of said two points having a V-shaped cross-section in the direction of said line, and the recess located at the other of said two points having a rectangular cross-section in the direction of said line; and spring means mounted on said supporting means urging said arresting arms downwardly toward said first and second vertical pins.

4. In a balance including supporting means, a knife edge on said supporting means, a horizontal beam supported by said knife edge, and two suspension members supported on the ends of said beam and adapted to be lifted off said beam, an arresting arrangement, comprising in combination, a beam arrest mounted on said supporting means reciprocable in vertical direction and adapted to engage said beam for moving the same be tween an operative position seated on said knife edge to an arrested position upwardly spaced therefrom; a pair of movable arresting arms extending from said supporting means outwardly towards said suspension members having outer ends located under said suspension members and adapted to engage said suspension members from below, and inner ends located in the region of said knife edge, each of said arresting arms being formed with three spaced recesses on the lower face thereof; two first vertical pins, each of said two vertical pins secured at its lower end to said supporting means and having a rounded upper end engaging a cup-shaped recess located at the inner end of one of said arresting arms supporting said arresting arm; two parallel elongated bridge members, each bridge member extending under one of said arresting arms intermediate the ends thereof and normal to the same, each of said bridge members being formed with two longitudinally spaced recesses at the bottom face thereof, one of said recesses being conical and the other having a V-shaped cross-section in transverse direction of said bridge member; two pairs of upwardly extending second pins having pointed upper ends, each pair of second pins secured at the lower ends thereof to the upper face of one of said bridge members and engaging two corresponding recesses in one of said arresting arms, one of said two recesses engaged by said second pins being conically shaped and the other having a V- shaped cross-section in a transverse direction of said bridge member, each pair of second pins located spaced from each other on a line extending normal to said arresting arms intermediate the ends thereof; two pairs of upwardly extending third pins, each pair of third pins secured at the lower ends thereof to said beam arrest and having upper pointed ends engaging said two recesses in one of said bridge members, each pair of third pins being vertically aligned with a corresponding pair of second pins; and spring means mounted on said supporting means urging said arresting arms downwardly toward said first and second pins.

References Cited in the file of this patent UNITED STATES PATENTS 1,404,426 Becker Jan. 24, 1922 2,404,601 Seyter July 23, 1946 2,567,161 Griflin Sept. 4, 1951 FOREIGN PATENTS 9,411 Germany Apr. 17, 1880 15,131 Germany Sept. 6, 1881 18,036 Germany May 10, 1882 273,694 Germany May 5, 1914