WO2011043943A1 - Quick mount load cell apparatus - Google Patents

Abstract

A quick mount assembly for mounting a load cell within a load cell apparatus includes a bracket connected in fixed position and orientation to a load cell support member and an adapter connected in fixed position and orientation to the load cell, with the load cell supportable on the bracket during installation and removal, and the bracket and adapter including features for accurately positioning and orienting the load cell within the apparatus.

Description

QUICK MOUNT LOAD CELL APPARATUS

CROSS-REFERENCE TO RELATED APPLICATIONS

[01] The present application claims the benefits of United States Provisional

Application Serial No. 61/249,359, filed October 7, 2009.

FIELD OF THE INVENTION

[02] The present invention relates generally to mounting apparatuses and to load cells and, more particularly to an interchangeable quick mount assembly for load cells used in a test stand or other operating apparatus.

BACKGROUND OF THE INVENTION

[03] Load cells, which measure the load or force applied by equipment, such as material test equipment during testing, are fundamental to the process of material testing and analysis. For example, it is known to provide load cells in test stands to determine the break strength of a material against which the test equipment provides force. In some installations, a load cell is installed as a semipermanent component that rarely requires changing. However, some users test a variety of materials that break at vastly different loads. The same test stand can be used for testing the different materials, but to obtain the most accurate measure of the load at which a test specimen fails it is desirable to closely match the load measurement capacity of the load cell to the predicted failure load of the test specimen. For example, when testing specimens of steel of varying gauges (i.e. thicknesses) it may be desirable to select a higher capacity load cell to test thicker gauges while using a lower capacity cell to test thinner gauges so as to achieve the desired resolution and accuracy at both high and low loads. If a limited number of testing machines are available for testing a variety of specimens, it may be necessary to change the load cells on a given machine when changing from one test specimen to another test specimen. In a high volume manufacturing environment, the changeover may take place several times each day. The changeover activity involves supporting the weight of the installed load cell, disconnecting and removing alignment and securing hardware for the installed cell, properly aligning and orienting the load cell to be mounted on the machine with the mounting hardware, and supporting and attaching the new load cell to the machine. These procedures can be cumbersome and difficult, especially since load cells can be reasonably heavy. The overall procedure of removing one of load cell and replacing it with another load cell can require significant time when performed several times a day. Time required for changing load cells adversely impacts the quantity of tests that can be performed at a facility.

[04] It is known to provide a machined dovetail groove on the top of a load cell and a post at the bottom of the moving member of the test machine or other apparatus on which the load cell is installed. The dovetail groove engages the post, and a screw in the post is tightened to secure the engagement of the post and dovetail groove. While this structure can facilitate the physical act of changing one load cell for another load cell by helping support the weight of the load cell, it is still somewhat cumbersome to use. The known arrangement has no means to ensure proper alignment or proper orientation of the load cell.

[05] Accordingly, a true quick mount apparatus for load cells would provide significant advantages, making load cell change easier and quicker.

SUMMARY OF THE INVENTION

[06] The present invention provides a quick mount assembly that supports the weight of a load cell for installation or removal, and provides self-alignment and orientation features for positioning the load cell during installation, thus facilitating frequent changeover of load cells.

[07] In one aspect of one form thereof a load cell apparatus having a load cell support member and a load cell mounted on the load cell support member is provided with a bracket mounted on one of the load cell support member and the load cell through a first interface including first alignment structure for fixed positioning and alignment of the bracket. An adapter is mounted on the other of the load cell support member and the load cell through a second interface including second alignment structure for fixed positioning and alignment of the adapter. The bracket and the adapter are configured for sliding reception and continuous support of the adapter in the bracket. A third interface includes third alignment structure for fixed positioning and alignment of the adapter and the bracket relative to one another.

[08] In another aspect of a form thereof, a load cell apparatus is provided with a load cell support member and a bracket mounted on the load cell support member in fixed position, the bracket including a center cavity with a cavity bottom, an open channel from a periphery of the bracket to the cavity, and ledges adjacent to the channel substantially aligned with the cavity bottom. A load cell is provided with an adapter mounted on the load cell in fixed position, the adapter including a pedestal having a neck slidable through the channel and a head slidable on and supported along the ledges and received in the cavity and supportable on the cavity bottom. Complementary locating structure between the bracket and the adapter establish relative positioning of the adapter in the bracket.

[09] In a further aspect of a form thereof, a quick mount assembly for connecting a load cell to a support member is provided with a bracket for fixed connection to the load cell support member, the bracket including a center cavity with a cavity bottom, an open channel from a periphery of the bracket to the center cavity, and ledges adjacent the channel substantially aligned with the cavity bottom. An adapter for fixed connection to the load cell includes a pedestal having a neck slidable through the channel and a head slidable on and supported along the ledges and received in the cavity and supportable on the cavity bottom. A fixed position pin is exposed in the cavity, and at least one notch in a periphery of the head is configured for receiving the fixed position pin therein with the head disposed in the center cavity.

[10] The quick mount assemble in a load cell apparatus facilitates efficient removal and replacement of a load cell in the apparatus.

[1 1] The quick mount assemble in a load cell apparatus facilitates accurate positioning and orientation of a load cell in the apparatus. [12] Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.

BRIEF DESCRIPTION OF THE DRAWINGS

[13] Fig. 1 is a perspective view of operating equipment having a load cell connected thereto by a quick mount load cell assembly;

[14] Fig. 2 is an exploded view of the assembly shown in Fig. 1;

[15] Fig. 3 is a perspective views of a bracket for the quick mount load cell apparatus;

[16] Fig. 4 is a another perspective view of the bracket shown in Fig. 3, but showing the side opposite the side of the bracket shown in Fig. 3;

[17] Fig. 5 is a plan view of the side of the bracket shown in Fig. 3;

[18] Fig. 6 is a cross-sectional view of the bracket shown in Fig. 5, the cross section being taken on line 6-6 of Fig. 5;

[19] Fig. 7 is a cross-sectional view of the bracket shown in Fig. 5, the cross section being taken on line 7-7 of Fig. 5.

[20] Fig. 8 is a perspective view of a load cell adapter for the quick mount load cell apparatus;

[21] Fig. 9 is a plan view of the adapter shown in Fig. 8;

[22] Fig. 10 is a side elevational view of the adapter shown in Fig. 8;

[23] Fig. 1 1 is a plan view of the adapter, show the face of the adapter opposite the face shown in Fig. 9;

[24] Fig. 12 is a cross sectional view of the adapter shown in Fig. 11, the cross section taken along line 12-12 of Fig. 1 1;

[25] Fig. 13 is a perspective view of the bracket attached to operating equipment; and;

[26] Fig. 14 is an exploded view of the assembly shown in Fig. 13.

[27] Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use herein of "including", "comprising" and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[28] Referring now more particularly to the drawings, a load cell quick mount assembly 100 is shown for connecting a load cell 102 within and as part of a test stand or other load cell apparatus 104. Load cell quick mount assembly 100 includes a bracket 106 which remains attached to apparatus 104 on which load cell 102 is used, and an adapter 108 which is mounted to the load cell 102. In the exemplary embodiment shown, bracket 106 is connected to a moving cross head 110 of apparatus 104 which supports load cell 102 in use. Load cell 102 includes a signal line 1 12, which is connected to recording and/or analysis equipment (not shown).

[29] Bracket 106 interfaces with cross head 1 10 with alignment structures that establish fixed positioning and orientation of bracket 106 on cross head 110. Adapter 108 interfaces with load cell 102 with alignment structures that establish fixed positioning and orientation of adapter 108 on load cell 102. Bracket 106 and adapter 108 engage one with the other and interface with alignment structures that establish fixed positioning and alignment of adapter 108 in bracket 106. It should be understood that a plurality of load cells 102 each can be provided with a similar adapter 108 so that when one load cell 102 is removed from bracket 106 and replaced with another load cell 102, the replacement load cell 102 is properly oriented and positioned relative to apparatus 104. Accordingly, a variety of load cells 102 can be provided with similar adapters 108 so that each load cell having an adapter 108 can be quickly and accurately installed on apparatus 104 by engagement with bracket 106.

[30] Bracket 106 is attached to cross head 110 by a plurality of screws or bolts

114. In the exemplary embodiment shown, three screws 1 14 are illustrated; however, other fastening arrangements, with more or fewer screws 114 and fasteners of other types, also can be used. An alignment washer 116 is disposed between bracket 106 and cross head 1 10.

[31] Bracket 106 defines a center cavity 1 18 having a cavity bottom 120 and an upper lip 122. Upper lip 122 receives alignment washer 1 16 and/or a protuberance or other prominent feature on cross head 1 10 to locate the bracket on the cross head together with the alignment washer and the fastening of screws or bolts 114 through bolt holes 124 provided in the bracket. An open receiving slot or channel 126 is defined from the outer periphery of bracket 106 and extends into cavity 1 18. Channel 126 is defined between ledges 128, 130 extending along opposite sides of channel 126. Channel 126 has no top or bottom between ledges 128, 130. Ledges 128, 130 extend to cavity bottom 120, which can be at a slightly displaced elevation from ledges 128, 130 to form a shallow pocket for receiving adapter 108, as will be described. A locating pin 132, which can be a precision dowel, is held in cross head 110 and is received in a precise locating hole 134 in bracket 106 to further position and orient bracket 106 accurately on cross head 110.

[32] Adapter 108 is configured to slide into cavity 118 via channel 126 and to be supported along ledges 128, 130 and received on cavity bottom 120. Adapter 108 includes a base 136 having holes 138 for attachment to load cell 102 via screws or bolts 140. An alignment counter bore 142 cooperates with a protrusion 143 on the top of load cell 102 to establish a fixed position and orientation of adapter 108 relative to load cell 102 due to precise machining of counter bore 142 and protrusion 143. A locating hole 144 can be provided extending into base 136 from the outer confronting surface that engages load cell 102 when adapter 108 is attached. A separate locating pin 146 or other protrusion from load cell 102 is received in locating hole 144 to establish a rotated position of adapter 108 on load cell 102 for accurate positioning and orientation of adapter 108 on load cell 102.

[33] Adapter 108 further includes a pedestal 148 including a head 150 and a neck 152. Neck 152 is appropriately sized to slide through channel 126, while head 150 has sufficient width to engage ledges 128, 130 and to be received in center cavity 118. A precision relationship by machining head 150 and center cavity 118 aligns adapter 108 relative to bracket 106, and therefore load cell 102 within test stand 104. Head 150 includes one or more notch 154 along the peripheral edge thereof to engage locating pin 132 and properly orient and position adapter 108 relative to bracket 106. In the exemplary embodiment shown, two notches 154 are provided on head 150 two allow multiple orientations.

[34] Since bracket 106 is established in fixed position and orientation relative to the test stand 104 or other equipment, adapter 108 is established in fixed position and orientation relative to load cell 102, and bracket 106 and adapter 108 are established in fixed position and orientation relative to one another, the quick mount assembly of the present invention promotes and facilitates proper positioning and orientation of load cell 102 within the test stand or equipment 104.

[35] As stated previously herein, bracket 106 is fixedly connected to the test equipment, and adapter 108 is fixedly connected to load cell 102. To connect the load cell to the test equipment, pedestal 148 of adapter 108 is slid along channel 126, with head 150 supported on and sliding along ledges 128, 130, and neck 152 sliding through channel 126 between ledges 128, 130. With head 150 supported on ledges 128, 130 during installation, the physical effort required to install load cell 102 is reduced, since the weight of load cell 102 is supported on the bracket. Pedestal 148 is slid along channel 126 until head 150 is received in center cavity 118 and settles into the pocket formed by cavity bottom 120. Providing bottom 120 as a shallow pocket slightly lower than ledges 128, 130 provides feedback to the installer when head 150 settles onto cavity bottom 120. Load cell 102 will remain supported in the bracket; with head 150 disposed on and supported by cavity bottom 120, and load cell 102 is not easily dislodged accidentally since bottom 120 is slightly beneath ledges 128, 130. As head 150 reaches a final position in cavity 118, load cell 102 can be rotated until one of the notches 154 engages locating pin 132. Load cell 102 is secured in its oriented and installed position by a bolt 156 having washers 158, 160, the bolt extending through cross head 110 and received in a bolt engaging hole 162 defined in pedestal 148. Tightening bolt 156 completes self-alignment and self-orientation of load cell 102 relative to cross head 110 if any residual misalignment or misorientation remained prior to tightening bolt 156. Further, notch 154 must be oriented to locating pin 132 for bolt 156 to align with and be received by bolt engaging hole 162, further ensuring proper orientation of load cell 102. The pocket formed by cavity bottom 120 provides sufficient radial clearance relative to adapter head 150 to allow changes in the angular orientation of the adapter. With bottom 120 slightly lower than ledges 128, 130, adjustment of the angular orientation can be made without concern for the adapter/load cell assembly slipping out of bracket 106.

[36] Use of test stand 104 having quick mount assembly 100 proceeds in known fashion. An advantage from the use of alignment washer 1 16 occurs if the use of test stand 104 commences on a high energy specimen without proper tightening of bolt 156. If adapter pedestal 148 were to impact cross head 1 10, damage to the test equipment could result. The use of washer 116 results in contact against washer 116, and possible damage to washer 116, while potentially minimizing damage to the more expensive test equipment.

[37] To remove load cell 102 from test stand 104, bolt 156 is loosened and removed. Load cell 102 remains supported in bracket 106 with head 150 on cavity bottom 120. Load cell 102 is then pulled from its installed position, with head 150 slid onto and along ledges 128, 130 to the outer periphery of bracket 106. As load cell 102 is removed from center cavity 1 18 and along ledges 128, 130, the weight of load cell 102 can be supported on bracket 106. An operator then lifts and removes the load cell quickly and efficiently from the outer periphery of bracket 106. Thereafter, a second load cell 102 having a similar adapter 108 can be installed in bracket 106 in the same manner as described above. [38] Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.

[39] Various features of the invention are set forth in the following claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A load cell apparatus having a load cell support member and a load cell mounted on said load cell support member, said load cell apparatus comprising:

a bracket mounted on one of said load cell support member and said load cell through a first interface including first alignment structure for fixed positioning and alignment of said bracket relative to said one of said load cell support member and said load cell;

an adapter mounted on the other of said load cell support member and said load cell through a second interface including second alignment structure for fixed positioning and alignment of said adapter relative to said other of said load cell support member and said load cell;

said bracket and said adapter configured for sliding reception and continuous support of said adapter in said bracket; and

a third interface including third alignment structure for fixed positioning and alignment of said adapter and said bracket relative to one another.

2. The load cell apparatus of claim 1, said bracket being mounted on said load cell support member and including a center cavity with a cavity bottom; an open channel from a periphery of said bracket to said cavity; and ledges adjacent to said channel at a different elevation than said cavity bottom.

3. The load cell apparatus of claim 2, including an alignment washer between said bracket and said load cell support member.

4. The load cell apparatus of claim 2, including a locating pin extending between said load cell support member and said bracket.

5. The load cell apparatus of claim 2, said adapter including a pedestal having a neck slidable through said channel and a head slidable on and supported along said ledges and received in said cavity and supportable on said cavity bottom.

6. The load cell apparatus of claim 5, said adapter having one of a counter bore and a protrusion and said load cell having the other of a counter bore and a protrusion, said protrusion being received in said counter bore.

7. The load cell apparatus of claim 5, said head defining a notch and said bracket including a locating pin received in said notch with said head in said cavity and supported on said cavity bottom.

8. The load cell apparatus of claim 7, said locating pin extending through said bracket into said load cell support member.

9. The load cell apparatus of claim 8, including a bolt extending through said load cell support member, and said adapter defining a bolt receiving hole engaged with said bolt.

10. The load cell apparatus of claim 1, said adapter including a neck and a head of a diameter wider than a diameter of said neck.

11. The load cell apparatus of claim 1, including a locating pin aligning said bracket and said support member.

12. The load cell apparatus of claim 11, said adapter defining at least one notch for sliding reception of said locating pin in said at least one notch.

13. The load cell apparatus of claim 1, including interchangeable load cells each having a said adapter receivable in and supportable on said bracket mounted on said load cell support member.

14. A load cell apparatus, comprising:

a load cell support member;

a bracket mounted on said load cell support member in fixed position, said bracket including a center cavity with a cavity bottom, an open channel from a periphery of said bracket to said cavity, and ledges adjacent to said channel substantially aligned with said cavity bottom;

a load cell;

an adapter mounted on said load cell in fixed position, said adapter including a pedestal having a neck slidable through said channel and a head slidable on and supported along said ledges and received in said cavity and supportable on said cavity bottom; and

locating structure between said bracket and said adapter establishing relative positioning of said adapter in said bracket.

15. The load cell apparatus of claim 14, including a pin projecting from said bracket into said cavity, and a notch on said head of said adapter for sliding reception of said pin in said notch.

16. The load cell apparatus of claim 15, including a bolt extending through said load cell support member, and said adapter defining a bolt receiving hole engaged with said bolt.

17. The load cell apparatus of claim 14, including a bolt extending through said load cell support member, and said adapter defining a bolt receiving hole engaged with said bolt.

18. A quick mount assembly for connecting a load cell to a support member, said quick mount assembling comprising:

a bracket for fixed connection to the load cell support member, said bracket including a center cavity with a cavity bottom, an open channel from a periphery of said bracket to said center cavity, and ledges adjacent said channel substantially aligned with said cavity bottom;

an adapter for fixed connection to said load cell, said adapter including a pedestal having a neck slidable through said channel and a head slidable on and supported along said ledges and received in said cavity and supportable on said cavity bottom;

a fixed position pin exposed in said cavity; and

at least one notch in a periphery of said head, said notch configured for receiving said fixed position pin therein with said head disposed in said center cavity.

19. The quick mount assembly of claim 18, said head including two said notches, each said notch configured for receiving said fixed position pin therein.

20. The quick mount assembly of claim 18, including a counter bore in a face of said adapter confronting a load cell, and a locating hole in a face of said bracket confronting a load cell support member, with a locating pin received in said locating hole.