79

NATIONAL BUREAU OF STANDARDS REPORT

2079

Two Warehouse Panel Fasteners

manufactured by

U. S. Thermo Control Company and Hussman Corporatio

by

H. Karger

C. W. Phillips

P. R. Achenbach

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Charles Sawyer, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

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NATIONAL BUREAU ©F STAN® ARDS HEFOflT

HES PROJECT NBS REPORT

1003-40-4700 November 25, 1952 2079

Two Warehouse Panel Fasteners

manufactured by

U. So Thermo Control Company and Hussman Corporation

by

H, Karger

Co W. Phillips

P. Ro Achenbach

to

Procurement Section

Headquarters, U 0 So Marine Corps

Department of the Navy

Washington 25, D. Co

The publication, repr

unless permission is o.

25, D. C, Such perm!

caily prepared If that

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

n part, Is prohibited

andards, Washington

)ort has been specifiiort for its own use

Two Warehouse Panel Fasteners

by

Ho Karger

Co Wo Phillips

Po R» Achenbach

ABSTRACT

Specimens of warehouse panel fasteners manufactured

by the Hussman Corporation and the U c S 0 Thermo

Control Company were tested for load-deflection of

the spring, maximum load of the spring assembly,

torque load of the cam assembly, and the maximum

load of the cam assembly. It was found that the

load required to produce a given deflection of the

Uo So Thermo Control spring was much lower than

that for the Hussman spring, but that the Hussman

spring would take a permanent set when loaded enough

to cause a deflection of l/£-inch„ The breaking

strengths of the two fastener assemblies were approximately equal. The U, S, Thermo Control Company

spring assembly and cam assembly were each essentially vapor-tight whereas the Hussman components were not,

I, INTRODUCTION

In accordance with a request by Headquarters, United States

Marine Corps, in a letter dated July 24, 1951, comparative tests

were made of two makes of warehouse panel fasteners, one manufactured by the Hussman Corporation of St, Louis, Missouri, the

other manufactured by U, S, Thermo Control Company of Minneapolis,

Minnesota, Mechanical tests were made of the load-deflection of

the spring, the maximum load of the spring assembly, the torque

load of the cam assembly, and the maximum load of the cam assembly

A total of six panel fastener assemblies, three each made by the

respective manufacturers, were submitted for test. Four of the

assemblies were destroyed during tests,

II, DESCRIPTION OF TEST SPECIMEN

The panel fasteners are used in the assembly of prefabricated

demountable warehouses. The various sections or panels of these

warehouses are held together by the panel fastener assemblies.

Each panel fastener assembly consisted of two separate parts, the

spring and eye assembly and the cam and hook assembly, with each

of the two parts being built into the edge of one of the two warehouse panels to be held together. The cam assembly of the
-

.

.

,
- 2

fastener was built to receive a hexagonal , 3/3” Allen-type lockwrench, which, when turned, caused engagement and tightening of

the hook of the cam assembly with the eye of the spring assembly,

thus locking the warehouse panels together, and compressing the

gaskets to prevent entry of air and water vapor 0

The panel fasteners submitted for tests were identified

as follows:

NBS Specimen 60-51

Three samples furnished by Hussman Company

NBS Specimen 61-51

Three samples furnished by th So Thermo Control Company

Figo 3 shows the Hussman specimen 60-51 as submittedo Fig„ 4

is a view of the same specimen after rupture, which occurred

during the test to determine the breaking strength of the component parts o Specimen 61-51, manufactured by U„ So Thermo

Control Company, is shown in Fig 0 5, as submittedo The same

specimen after rupture can be seen in Fig 0 6 0

It should be noted that all the figures referred to are

composite, and the two mating pieces are not shown in a true

size relationship,. The Hussman fastener in Figures 3 and 4 and

the Uo So Thermo Control fasteners, in Figures 5 and 6 had the

following approximate dimensions:

Hook Section Eye Section

Width

(inclo Depth

Allen (inclo Depth

Wrench extended (incl.

Length Socket) hook) Length Width eye)

Hussman 5-7/3" 4" 4-1/2” 3-1/2” 2-3/3" 2”

Uo.S o Thermo Control 5" 4-1/2” 4" 4-3/3” 2” 2-1/2”

The weight of the complete Hussman fastener was 1 lb-7oz.

(Hook 1 lbo-1 0 Zo, Eye 6 oz„) whereas the weight of the

Uo So Thermo Control fastener was 1 lb-12 oz„ (Hook 1 lb 0 -l/2 oz„,

Eye 11-1/2 oz 0 )

3 -

III. TEST PROCEDURE

A load-deflection test was made on each of the spring

assemblieso This was done by loading the springs with known

weights and observing the amount of deflection.,

Tests to determine failure of the panel fasteners were

run separately for each assembly of the fasteners

.

Tests to determine the torque-load characteristics of

the cam assemblies were made at two different positions of

the cam hook a A torque of 500 lb-in. was applied to the cam

wrench and the pull exerted by the cam hook under this condition was measured on a testing machine. The tests were made

with the cam assemblies in approximately an open position and

in approximately a half-closed position.

IV. TEST RESULTS

The following table summarizes the results obtained for

all tests except the load-deflection tests of the spring assemblies : RESULTS OF TESTS OF PANEL FASTENERS

Specimen 60-51 Specimen 61-51

Test Hussman U.S. Thermo Control

Maximum load sustained

by the spring and eye

assembly, lb. ' 29$0 (a) 1$70 (b)

Maximum load sustained

by the hook and cam

assembly, lb. 2210 (c) 3$50 (c)

Pull exerted by hook

with 500 lb-in. applied

to cam wrench, lb.

Assembly open (d) 1200 960

Assembly half-closed (d) $90 1040

(a) eye failed

(b) spring seat in the housing pulled out

(c) hook failed

(d) approximate positions, not directly comparable

- 4

The results of the load-deflection tests of the spring

assemblies are shown in Figures 1 and 2 for specimen 61-51 and

60-51, respectively* A comparison of these two graphs shows

that the U* S* Thermo control spring required a much smaller

loading than the Hussman spring to obtain the same amount of

deflection* The springs of both specimens came to a mechanical

stop after a deflection of approximately l/$tf

, hence the loads

were not increased after a deflection of about 0*12 inches was

reached* Fig* 2 shows that a permanent set occurred in the

Hussman spring after having been loaded sufficiently to cause

a deflection of about 0 o 12 inches*

Fig* 2 shows that a break in the initial deflection curve

occurred at a loading of about $00 lb* It is believed that

this was the elastic limit of the spring material* The load

of 1200 lbs* exerted by the Hussman cam assembly, as shown in

the table of results, when a 500 lb-in* torque was applied to

the cam wrench should be considered a maximum value since this

is simply the stationary load as exerted on the testing machine*

It is not known how much of the exerted torque would be lost

in friction when the cam- and spring assemblies are actually

being engaged*

In actual use, the amount of spring deflection and whether

or not any permanent set would occur in the Hussman spring,

would depend on the load-deflection characteristics of the gasket

material used between the panels* A torque of 500 lb-in. or more

could probably be exerted on the cam wrench under some circumstances, and if the deflection resistance of the gaskets reached

values approaching 1150 lb* for the Hussman spring or 230 lb*

for the U* S* Thermo Control spring before the hook was fully

closed, the springs would be deflected against the permanent

mechanical stop* Such circumstance might arise if the panels

were warped or were being assembled with ice or dirt around the

edges that prevented drawing the panels together on the gaskets

readily*

The spring deflection of l/$ inch would provide a safety

factor against breakage of the fasteners by conditions that tended to pull the panels apart after assembly in warehouses that

were satisfactorily assembled without deflecting the spring*

In design of panels that are to use these fastener assemblies

attention should be given to the compression required for the

gaskets so the spring deflection of the fasteners will not

occur while compressing the gaskets during normal assembly*

The U* S* Thermo Control spring was a coil spring, and its

recovery characteristics under compression were better than

those of the Hussman spring* It should be pointed out, though,

that at 0*12" deflection the pull of the U* S* Thermo Control

fastener would be only 230 lbs* as compared with 1025 lbs. for

the Hussman as indicated on the recovery curve*
]
- 5 -

The breaking strength of the total panel fastener assemblies was very nearly alike for both specimens submitted. As

can be seen from the table, the spring assembly of the U. S.

Thermo Control fastener failed at a loading of 1#70 lbs. The

cam assembly of the Hussman fastener failed at a loading of

2210 lb., a difference of 340 lb 0 between the two makes of

fasteners. The results in the table also indicate that the

mechanical advantage of the Hussman cam assembly decreased

about 25 percent between the open and half-closed positions

whereas it increased slightly for the U. S, Thermo Control

cam assembly between the same two positions of the hook.

An additional feature of the Hussman fastener that would

be of assistance in actual erection of warehouses was the provision of a mechanical stop which prevented the hook from dropping

completely below the eye during assembly to a position where it

could not engage the eye. In the case of the U, S. Thermo

Control fastener, it was possible for the hook to drop completely below the eye. If this happened to on.e or more hooks during

panel erection, it would be necessary to release all other

fasteners and separate the panels before any of these hooks

could be returned to a position for proper engagement.

V. CONCLUSIONS

Based on the test results quoted above, it is believed

that the two makes of panel fasteners as submitted, are satisfactorily equivalent for the intended purpose 0 The small differences in the breaking strengths and the mechanical advantages

of the cam assemblies are not considered to be significant when

viewed in the light of the overall usefulness of the two devices.

However", there was a marked difference in regard to the

vapor seal feature between the two makes of panel fasteners, as

submitted. The construction of the Hussman fastener would permit passage of water vanor through either the spring or the cam

assembly, whereas the two assemblies of the U. S. Thermo Control

fastener were comparative^ tight. If there were a need to

obstruct the flow of water vapor through the panel fasteners,

the U. S. Thermo Control fastener would be definitely superior.

The importance of the vapor seal characteristics offered

by the hardware alone would be determined by the relative vapor

transmission resistance of the wood breaker strips at the edges

of the panels including all the cuts for hardware, and the type

of joint between the breaker strip and the panel face materials.

If the outer gasket provided a good vapor-tight joint, the vapor

resistance of the panel edges would not be important. If the

outer gasket was not tight, the vapor resistance of the entire

panel edge, rather than the hardware alone, becomes significant.
!I
Since with present construction the gaskets may be damaged byhandling of the panels, either the inner or outer gasket is

likely to offer the greater resistance to vapor transmission

for any particular erection of a warehouse 0 Therefore, the

vapor resistance characteristics of the panel fasteners should

be comparable to that of the breaker strip and its joints

with the facing materials 0 A panel fastener with poor vapor

resistance in a good breaker strip construction could be a

cause of panel failure, whereas a panel fastener with superior

vapor resistance in a breaker strip construction of poor vapor

transmission resistance might not be justified economically

.
'
Load

,

lb

Thermo Control spring

Deflection, in.

6.4/10-643

G-6899 Fig. /

Load

,

ib

Hussman spring

Deflection , in.

6.4/10-643

G-6809 Fig.

NBS



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FIG



THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act

of Congress, March 3, 1901, as amended by Congress in Public LaAv 619, 1950.

These include the development and maintenance of the national standards of

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