US2980414A

US2980414A - Compression bracket

Info

Publication number: US2980414A
Application number: US571974A
Authority: US
Inventors: Jr Joseph A Perry; William M Haselton
Original assignee: Cherry Burrell Corp
Current assignee: Cherry Burrell Corp
Priority date: 1956-03-16
Filing date: 1956-03-16
Publication date: 1961-04-18
Anticipated expiration: 1978-04-18

Description

April 1961 J. A. PEIIQRY, JR, BT51. 2,980,414

- COMPRESSION BRACKET Filed March 16, 1956 5 Sheets-Sheet 1 INVENTORS.

April 18, 1961 J. A. PERRY, JR., ETAL 2,980,414

COMPRESSION BRACKET Filed March 16, 1956 s Sheets-Sheet 2 Jja I I ,1 39 M 0 a9 r ml 41 iv F INVENTORS.

{7 J1 rfosep/zal erryafn 115 II MZZZ'QIWM Haselzorz April 17961 J. A. PERRY, JR., ETAL 2,980,414

COMPRESSION BRACKET 3 Sheets-Sheet 3 Filed March 16, 1956 United States Patent 1 2,980,414 COMPRESSION BRACKET Joseph A. 'Perry, Jr., Morton Grove, Ill., and William M.

Haselton, Cedar Rapids, Iowa, assignors to Cherry- Burrell Corporation, Chicago, 111., a corporation of Delaware Filed Mar. 16, 1956, Ser. No. 571,974 Claims. (Cl. 177-211) Our invention relates to a compression bracket in which a suitable load-sensing device or cell may be mounted for measuring weights or loads, and has reference more particularly to a bracket type of device for isolating compressive force in a column from concurrent torsional, bending, or side-thrust forces and the like, so as to measure only the compressive force applied thereto.

The compression bracket embodying our invention is designed for installation in the supporting members or legs of platforms, conveyors, bulk material containers such as storage tanks and bins, and the like. The bracket is adapted to receive a force-measuring device or cell, such as the unit described in Patent No. 2,709,790 to W. R. Swanson, issued May 31, 1955. The cell is interposed between opposed portions of the bracket. The bracket serves to transmit only compressive type forces to the cell and to prevent transmission of moment type forces and the like thereto. The bracket will hereafter be disclosed in combination with the aforesaid type of force-measuring unit or cell, but it should be understood that other types of units, including those of the electronic, hydraulic, and pneumatic types, may be used with our compression bracket.

It is the principal object of our invention to provide a compression bracket which will communicate compressive force to a force-measuring unit and which will at the same time prevent communication to such unit of other type forces that may be applied to the compression bracket.

It is another object of our invention to devise such a compression bracketwhich may be incorporated readily in the supports for storage tanks, bins, hoppers, weighing platforms, and the like at the time of manufacture, or which may be added conveniently to existing installations of such equipment.

It is a further object of our invention to design such a device which is simple in design, dependable in operation, and readily adaptable to a wide variety of installations, these and other objects being accomplished as hereinafter described, reference being had to the accompanying drawing in which:

Fig. 1 is a perspective view of a storage tank showing compression brackets installed inthe legs thereof;

Fig. 2 is a sectional view through a conveyor having a compression bracket in a supporting member thereof;

Fig. 3 is a top view of the compression bracket embodying our invention as taken on the line 3-3 of Fig. 2;.

Fig. 4 is a side view of compression bracket shown in Fig. 3;

Fig. 5 is a view on the line 55 of Fig. 4;

Fig. 6 is a diagrammatic side view of said bracket showing the effect of certain forces thereon;

Fig. 7 is a diagrammatic view of one of the other sides of said bracket showing the effect of other forces thereon;

Fig. 8 is a side view of a modified form of compression bracket; and

Fig. 9 is a top view of bracket shown in Fig. 8.

Referring now to the drawing, the compression bracket of our invention is designated generally by the reference :numeral 10 and is shown in Fig. l as mounted between the upper parts 11a and lower parts 11b of supporting legs at the four corners of a storage tank 12. Each com- 2,980,414 Patented Apr. 18, 1961 ice pression bracket 10 is provided with a load sensing unit or cell 13, preferably of the type disclosed in Patent No.

2,709,790. The load cells 13 are connected in a suitable electrical circuit through the cable 14 to an indicator 15. The compressive force or weight exerted through the brackets 10 on the respective load cells 13 is indicated cumulatively on the indicator 15 so that the total weight in the storage tank 12 may be registered thereon. As explained in Patent No. 2,709,790, the indicator 15 may be adjusted in a manner to register zero when the storage tank 12 is empty, thus permitting measurement of the weight of the contents when additional load is exerted on the load cells 13 and communicated through the cable '14 to the indicator 15.

It will be understood that Where weight-sensing units of other types such as pneumatic or hydraulic are employed, the force or weight exerted thereon will be communicated in a suitable manner to similar indicators.

Another type of installation is shown in Fig. 2 wherein a conveyor belt or platform 16 moves between guides 17 mounted on a frame 18. The frame 18 is mounted on a support similar to the legs on which the storage tank 12 is mounted, comprising an upper leg part 11a and a lower leg part 11b. A compression bracket 10 is interposed between the upper and

lower leg parts

11a and 11b, and a load cell 13 is provided therein. As the load shown on the belt or platform 16 in Fig. 2 passes over the frame 18, the weight of the load exerts a compressive force through the upper leg part 11a and the bracket 10 on a load cell 13. In this type of installation, where but a single load cell 13 is employed, the force or weight measured by the one load cell 13 would be communicated directly to an indicator (not shown).

The bracket 10 has a top collar 19 which may be threadably or otherwise engaged to the lower end of the upper leg part 11a. A corresponding bottom collar 20 is similarly engaged to the upper end of the lower leg part 11b. The top collar 19 is provided on its underside with an end wall 21 which may be welded or otherwise secured thereto. A hardened block or rocker plate 22 is mounted on the underside of the wall 21, said rocker plate 22 having a downwardly facing lengthwise V-groove 23. The bottom collar 20 has a similar end wall 24 with a rocker plate 22 hearing against its upper side, with a V-groove 23 facing and aligned with the corresponding V-groove 23.

Each of the rocker plates 22 is preferably formed with a slight convex curvature on its back side as shown in Fig. 5 so as to permit a limited end-to-end rocking movement as it bears against the

respective end wall

21 or 24. The rocker plates 22 are preferably notched at both ends of the V-groove 23 to receive the pegs 25 which are secured to the

end walls

21 and 24 to insure proper positioning of the rocker plates 22.

The load cell 13 as shown herein comprises a casing with load responsive elements (not shown) enclosed therein. The casing of the load cell 13 is provided on opposite faces with knife-edge bearing strips 26 which are adapted to exert measurable compressive pressure on the load responsive elements within the casing. The opposed knife-edge bearing strips 26 are seated in the V-grooves 23 of the rocker plates 22. Thus, a load on the upper leg 11a is supported by the rocker plate 22 resting on the top knife-edge 26 of the load cell 13. Likewise, support is provided by the lower leg part 11b through the rocker plate 22 and the bottom knife-edge 26 of the load cell 13 resting in the V-groove 23 of said rocker plate 22. The load cell 13 is thus compressed between the two knife-edges 26 when a load is imposed upon the upper leg part 11a.

The top collar 19 is provided with

shoulders

27 and 28 extending somewhat tangentially in the same direction from opposite sides of the collar 19, andeach shoulder I 27 and 28 is provided with a downwardly depending arm or

leg

29 and 30, respectively, said

arms

29 and 30 being substantially parallel. r

The bottom collar 20 has

shoulders

31 and 32 and

arms

33 and 34 corresponding to those with which the top collar 19 is provided except that the relative position is reversed. Thus the

shoulders

31 and 32 extend tangentially from the collar 20 in a direction opposite to that of the

shoulders

27 and 29. Likewise, the

arms

33 and 34 are upwardly depending from the

shoulders

31 and 32, respectively, and are substantially parallel, as shown in Fig. 4.

Corresponding holes 35 are provided at the juncture of the

shoulders

27 and 28 with the

arms

29 and 30, respectively, said holes being axially aligned. Likewise, axially aligned holes 36 are provided at the junctures of the

shoulders

31 and 32 with the

arms

33 and 34, respectively.

The free ends of the

arms

29 and 30, respectively, are provided with axially aligned holes 37; and the free ends of the

arms

33 and 34, respectively, are provided with axially aligned holes 38.

Axle members 39, which are of greater length than the distance between the respective pairs of axially aligned

holes

35, 36, 37, and 38,'are disposed in said corresponding pairs of holes and protrude therebeyond at their respective ends. An upper stabilizer frame 40 of generally rectangular form and with holes corresponding to and aligned with

holes

35 and 38 at each side of the bracket 16 is mounted on the respective ends of the axle members 39 protruding through the

holes

35 and 38. A corre sponding lower stabilizer frame 41 of generally rectangular form is mounted below and in a plane substantially parallel with that of the upper stabilizer frame 40.. Lower stabilizer frame 41 has holes corresponding to and aligned with the

holes

36 and 37 at each side of the bracket 13, and the respective holes thereof are engaged upon the ends of the axle members 39 protruding through the

holes

36 and 37. In this manner, the top collar 19 with its depending

shoulders

27 and 23 and

arms

29 and 39 is linked together with the bottom collar 20 and its depending

shoulders

31 and 32 and

arms

33 and 34 by the axle members 39 in a relatively square arrangement as shown in Fig. 4.

The ends of the axle members 39 are threaded to receive the nuts 42 which serve to hold the bracket assembly together. The end portions of the axle members 39 engaged by the stabilizer frames 40 and 41 serve as bearings and permit free upward and downward movement of the top collar 19 with respect to the bottom collar 20 and the stabilizer frames 40 and '41 serve to maintain a parallelogram relationship between the two component parts of the bracket 10. Thus the V-groove 23 of the top collar 19 remains parallel with the V-groove 23 of the bottom collar 20 notwithstanding relative movement of said

collars

19 and 20 toward and away from each other.

It will be understood that when the load cell 13 is interposed between the

respective collars

19 and 20 with the knife-edges 26 seated in the respective V-grooves 23, the bracket lti permits vertical or compressive force to be applied to the load cell 13 without any restraining or interfering influence.

The reaction of the bracket 16 to the application of various forces is illustrated in Figs. 6 and 7. In Fig. 6, the primary force to which the bracket is subjected is the compressive force indicated by the two arrows C. At the same time, however, it is subjected to a secondary force, the bending momentindicated by the two arrows M. This may be caused by any of a number of factors such as angle of mounting, movement of load, or the like. It is to avoid communication of such secondary force to the load cell 13 that a bracket 19 is required. Since the efiect of the bending moment is to urge the upper pair of axles 39 toward each other and the lower pair of axles 39 apart, it may be said that the secondary force is compressive on the upper stabilizer frame 40 and tensile on the lower stabilizer frame 41. Since the two forces are resisted by said

frames

40 and 41, respectively, no bending moment can be communicated to the load cell 13. Thus as between compressive force CC and the bending moment MM in Fig. 6, only the compressive force is exerted upon the load cell 13 and thus is the only force measured thereby.

Fig. 7 shows the effect of a bending moment N-N applied to bracket 18 at right angles axially to the bending moment MM of Fig. 6. The bending moment N-N is resisted by the axle members 39 in combination with the upper and lower stabilizer frames 40 and 41 because of the engagement of the axle members 39 in the

holes

35, 36, 37, and 38 of the

shoulders

27 and 28 and their depending

arms

29 and 30 and the

shoulders

31 and 32 and their depending

arms

33 and 34. Since this bracket assembly will not yield to the bending moment NN, that moment cannot be transmitted to the load cell 13 and the only force so transmitted is the compressive force CC in the same manner as in Fig. 6.

Likewise, any other bending or torsional moments or force other than compressive applied to the bracket 13. are resisted. Thus the bracket 10 is incapable of transmitting such forces to the load cell 13. Moreover, as it evident from the'design of bracket 10, it is incapable of supporting any compressive load. Therefore, it is only by virtue of the interposition of the load cell 13 that the upper portion of the bracket 10 is supported with respect to the lower portion. As a result, the load cell 13 receives the total compressive force exerted upon the bracket 10 and receives none of the other forces or moments which may be applied thereto.

Referring now to Figs. 8 and 9, the modified form of compression bracket shown therein employs the same principles as those employed with respect to the heretofore described bracket 10, but the bracket of Figs. 8 and 9 is adapted to measure extremely heavy loads with a load cell 13 capable of bearing only a fraction of such loads.

As shown in Fig. 8, the bracket comprises a top collar 43 and a bottom collar 44. End walls 45 and 46 are provided in the top collar 43 and the bottom collar 44, respectively. The top collar is provided at opposite sides. with a pair of corresponding offset downwardly depending arms or legs 47 and the bottom collar 44 isprovided with a similar pair of offset upwardly depending arms or legs 48. Corresponding aligned holes 49 are provided in the legs 47 adjacent the top collar 43 and similarly aligned holes 50 are provided at the lower ends of said legs. Likewise, corresponding aligned holes 51 are provided in each of the legs 48 adjacent the bottom collar 44 and similarly aligned holes 52 in the free upper ends of said legs 48. Axle members 53 of greater length than the distance between said pairs of

holes

49, 50, 51, and 52 are engaged therein and protrude outwardly therefrom at each side of the

legs

47 and 48. An upper rectangular stabilizer frame 54 is provided with holes corresponding to and aligned with the

holes

49 and 52 in the

legs

47 and 48, said holes in the stabilizer frame 54 being engaged upon the protruding ends of the axle members 53. Likewise, a lower rectangular stabilizer frame 55 is provided with holes corresponding to and aligned with said

holes

50 and 51 and the holes of said stabilizer frame 55 are engaged upon the outwardly protruding ends of the axle members 53 engaged in the

holes

50 and 51. The bracket of Figs. 8 and 9 is thus similar in general construction to the bracket 10 heretofore described.

The end wall 46 of the bottom collar 44 is provided on its upper face with a rocker plate 56, the back side of which is convexly curved as heretofore described in connection with rocker plates 22. The rocker plate 56 has an upwardly disposed knife-edge 57 which extends at right angles on said rocker plate 56 to the axis of the curvature of the back side thereof. The knife-edge 57 serves as a fulcrum to support an arm 58. The stub end 59 of said arm 58 is provided with transverse V- grooves 60 and 61. The elongated end 62 of the arm 58 is provided adjacent its tip with a transverse V- groove 63.

The end Wall 45 of the top collar 43 is provided at one side with an inner V-groove 64 and an outer V-groove 65 facing and aligned with the corresponding V-grooves 60 and 61 on the stub end 59 of the arm 58. The end wall 45 has a projection 66 at the side opposite to the location of the V-

grooves

64 and 65 aligned and substantially coextensive with the elongated end 62 of the arm 58. The projection 66 is provided adjacent its tip with a down wardly facing rocker plate 67 with a lengthwise groove 68 on its face, the back side of said rocker plate 67 being curved as heretofore described in connection with the rocker plates 22.

A load cell 13 is interposed between the V-groove 63 near the tip of the elongated end 62 of the arm 58 and the rocker plate 67 near the end of the projection 66. The arm is provided with a transverse groove 69 between the elongated end 62 and the stub end 59, said groove being engaged upon the knife-edge 57 which serves as a fulcrum. A double edge knife bar is interposable between facing V-

grooves

60 and 64 or 61 and 65. As shown in Fig. 8, said knife bar 70 is seated at its respective sides in the V-grooves 60 and 64.

Thus when a load is imposed upon the top collar 43 the greatest proportion of the load is carried by the knife bar 70 resting on the stub end 59 of the arm 58, the load being exerted therefrom through the rocker plate 56 to the bottom collar 44. A predetermined fraction of the load is transmitted through the projection 66 to the load cell 13 and thereby to the elongated end 62 of the arm 58. As will be understood, the exact positioning of the knife bar 70 with respect to the axis of the top and

bottom collars

43 and 44 and the spacing of the load cell 13 at the opposite side of said axis determines what proportion of the load is exerted through the load cell 13. In the form illustrated in Fig. 8, the load cell 13 carries 20 percent of the load when the knife bar 70 is seated in the inner V-grooves 60 and 64 and carries 25 percent of the load when said knife bar 70 is seated in the outer V-grooves 61 and 65.

As heretofore described, the load cell of Figs. 8 and 9 would be connected by suitable cable (not shown) to an indicator (not shown) which would be adjusted to register the total load by virtue of the fraction of the load communicated to it from the load cell 13.

While we have shown and described our invention in preferred forms, it will be understood that various modifications and changes can be made in the specific features thereof and in the general assembly as well as in the type of load cell or load measuring unit employed therewith without departing from the spirit of our invention, the scope of which is to be determined by the appended claims.

We claim:

1. A bracket of the class described comprising the combination of an upper block and a lower block having portions disposed in face-to-face spaced apart relation to receive a load-sensitive cell therebetween, each of said blocks having two corresponding spaced apart leg members projecting toward one side of the other block in relatively straddling relation, each block being provided with a. substantially rectangular frame pivotally mounted on the leg members thereof adjacent the block in a plane substantially perpendicular to that of said leg members, said frame also being pivotally connected to the free ends of the legs of the other block.

2. A bracket of the class described comprising the combination of an upper block and a lower block having portions disposed in face-to-face spaced apart relation to receive a load-sensitive cell therebetween, each of said blocks having two corresponding spaced apart leg members projecting toward one side of the other block in relatively straddling relation, each block being provided with a substantially rectangular frame pivotally mounted on the leg members thereof adjacent the block in a plane substantially perpendicular to that of said leg members, said frame also being pivotally connected to the free ends of the legs of the other block, each block being provided with means for engagement with a supporting member of a device to be weighed.

3. A compression bracket for a force measuring device mounted between two relatively movable aligned members to which force is applied, said bracket comprising independent connecting means for securing said bracket to each of said relatively movable members, said means including portions disposed in face-to-face spaced-apart relation to receive the force measuring device therebetween, each of said means having a pair of arms extending substantially in the direction of the force to be measured and oppositely to the arms of the other means, and substantially rectangular frames pivotally connected to one pair of arms adjacent their connecting means and to the other pair of arms at their free ends, said frames being disposed parallel to each other and perpendicular to said arms thereby forming a parallelogramrnatic structure.

4. A compression bracket for a force measuring device mounted between two relatively movable members to which force is applied, said bracket comprising a support means secured to each of said members, each of said sup port means having a shoulder, said shoulders being disposed in spaced-apart relation to receive the force measuring device therebetween, an arm extending from each of said shoulders along a line substantially parallel to the applied force, the arm of one support means extending oppsitely to the arm of the other support means, and means interconnecting said support means by pivotal connection with the arm of one support means and the shoulder of the other support means, said last mentioned means and said arms forming a parallelogrammatic structure, the sides of which are pivotally interconnected.

5. A compression bracket for a force measuring device mounted between two relatively movable aligned members to which compressive force is applied, said bracket comprising independent connecting means for securing said bracket to each of said relatively movable members, said means including portions disposed in face-to-face spaced-apart relation to receive the force measuring device therebetween, each of said means having an arm extending substantially in the direction of the force to be measured and oppositely to the arm of the other means, and substantially rectangular frames each connected to one arm adjacent its connecting means and to the other arm at its free end, said frames being disposed parallel to each other and perpendicular to said arms thereby forming a parallelogrammatic structure.

References Cited in the file of this patent UNITED STATES PATENTS 308,440 Smith Nov. 25, 1884 2,090,188 Dahlstrom Aug. 17, 1937 2,411,023 Bruns Nov. 12, 1946 2,634,966 Williams Apr. 14, 1953 2,659,592 Wetsel Nov. 17, 1953 2,666,262 Ruge Jan. 19, 1954 2,670,195 Baker Feb. 23, 1954 2,767,974 Ballard et al. Oct. 23, 1956 2,802,660 Williams Aug. 13, 1957 2,805,055 Swanson Sept. 3, 1957 2,812,935 Mettler Nov. 12, 1957 2,822,095 Buckingham Feb. 4, 1958 FOREIGN PATENTS 301,121 Great Britain Nov. 29, 1928 427,347 Great Britain Apr. 23, 1935 761,259 Great Britain Nov. 14, 1956