Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
33
1 LAGGING MEMBER AND METHOD FOR BELT PULLEYS,
P~OCESSING ROLLS AND THE LIKE
by
~II,LIAM G. ~OLZ
The invention relates to what is commonly
referred to as pulley lagging, i.e., an elastomeric tread
product which is supplied to the peripheral surfaces of
belt pulleys, processing rolls and the like for the purpose
of improving belt traction/ to increase belt life by
eliminating slippage, and to promote belt alignmentO The
product is equally applicable to conveyor belt idler rolls
and many types of rollers used in industry as processing or
driving rolls.
~CKGROUN~ ART
Rubber lagging is most commonly applied to steel
pulleys~ rollers and the like by rubber companies having
special eqwipment for this purpose. When the lagging is
wornr it is normal practice to remove the rolls from
service and send them to a rubber roll covering facility
for renewal. This may require temporary shut-down of the
user's production line and is otherwise both costly and
time consuming.
Some years ago applicant evolved a system for
applying lagging to pulleys which had the advantage of
being applied in the field as desired by the user~ This
system involved the manufacture by a rubber company and
, ~
-2~ 33
1 supplyiny through trade channels to the ultimate user, of
arcuately formed steel backing plates on which the rubber
lagging i6 bonded. The units have a preformed curvature to
rest upon and mate with the roll periphery to which they
are applied, e.g.~ rolls of designated diameters. The
structure referred to is illustrated in U.S. Patent Mo.
3,354,735 wherein the backing plates are designed for
mounting in guide and retaining m.embers which are welded or
otherwise fastened to the pulley face. This particular
structure has the advantage of being applied and renewed as
required by the user. Somewhat similar techniques for
using lagging sections of preformed curvatures which are
bolted to the face of the pulley are illustrated in U.S.
Patent Nos. 2,707,403 and 3,010,332.
One of the disadvantages of lagging products
heretofore available is that moisture, sand and other
abrasive particles will work themselves under the metal
plates and corrode and abrade away the metal plate support
for the product. In khe case of Patent No. 3,354,735, the
retainer strips are of necessity fixed, as by welding to
the pulley periphery, thus minimizing Elexibility in the
positioning of the lagging sections on the pulley and
almost inevitably resulting in an imbalanced condition
Also some relative movement is inherent between the lagging
2~ sections and the retaining strips and the roll periphery
which results in wear and abrasion and premature failure of
the parts.
Attempts have also been made to prefor~ a full
circle endless tire which is intended to be driven upon the
3~ periphery of only one corresponding diameter wheel. This
technique re~uires the manufacture of specified sizes for
each wheel diameterO Examples of such proposals can be
found in U.S. Patent Nos. lr636,492, 1,765,402, 2,369,635,
2,673,469, 2,701,937, 2,778,234, and 3,3181165a
For certain limited usages, fabric reinforced
belting has been used for lagging. The practice is to cut
the belting into a relatively narrow width strip which is
-3~ ~ 3~
1 then spirally wound on the pulley with an adhesive,
covering l00~ and fastening at various poinks and at the
opposite end~ of the belting strip. This type of lagginy
is subject to stretchin~ and premature failure and is
essentially unidirectional in its operation, i.e., in the
direction of tiyhtening of the belting strip on the roll.
Moreover, there is a disadvantage in having to work with
cements and glues needed and universally used in the
application of the belting strip. The application of
adhesives is costly, messy and difficult, particularly over
wide temperature and humidity ranges.
DISCLQSURE OF INV~NTIQN
The lagging member of the present invention is a
bonded integral laminated structure comprising an interior
sheet of flexible non-extensible material, a relatively
thick layer of elastomeric lagging material on the normally
outer side of the sheet and a relatively thin coating or
laminae of elastomeric, rubber-like, material on the
normally underside of the sheet. The laminated sandwich
structure is flexible and may be readily wrapped on the
outer surface or wall of the pulley or roll. The
circumferentially spaced ends of the member are fastened to
the roll periphery with the ru~ber-like coatiny at the
underside of the member in frictional engagement with the
periphery. This rubber undercoating prevents slippage and
movement between the member and the roll; prevents
corrosion and abrasive wear, seals against moi~ture and
foreign materials entering between the pulley and lagging
member, improves contact of the lagging member with
irregular roll surfaces, facilitates the contouring of the
product to the curvature of the roll and prevents kinking
or sharp bending of the interior non~extensible sheet. The
function of the intermediate sheet is to provide a no-
stretch or yield laminate, preventing distortion ormovement o~ the assembly while turningl such as wave build-
up action ahead of the point of work load and to
.
7~
1 cooperatively support the fastening of the member to the
pulley. The third, outer ply or layer is designed for
contacting the work and may be of a multitude of designs
and compositions depending on the operation involved, e.g.,
pulley lagging, lumber feeding, rice hulling, food
processing, etc.
An object of the present invention is to provide
a lagging product which can be reliably and economicaliy
produced in a flat state without necessity of pre-
contouring and which may be simply cut by the user tolengths to fit various pulley or roll diameters or leng~hs,
and which may be easily and readly applied on site at the
user's place with ordinary skill and available shop
equipment. As a result, the user only need keep one size
of lagging in stock for applying lagging to all of user's
pulleys, processing rolls and the like in the plant, thus
eliminating the need for keeping on hand a great variety oE
sizes and shapes of preformed lagging to fit pulleys and
rolls of different sizes.
Another object of the present invention is to
provide a lagging product and applying method which is
flexible in enabling the selective coverage of the pulley
or roll to the peripheral area required.
A further object of the present invention is to
provide for the most easy and effective attaching of the
lagging member to the pulley surface by weldiny which no~
only affords rapid and effective attachment but insures, on
the ensuing cooling and contraction of the intermediate
bonded sheet, the drawing of the rubber undercoating into
tight fitting gripping relation on the pulley periphery.
The invention possesses other objects and
features of advantage, some of which of the foregoing will
be set forth in the following description of the peferred
form of the invention which is illustrated in the drawings
accompanying and forming part of this specification. It is
to be understood, however, that variations in the showing
made by the said ~rawings and description may be adopted
_5~ 9733
1 within the scope of the invention as set forth in the
claims.
EEI~E_rES~BIPTION OF THE ~
FIGURE l is a plan elevaticn of a lagying product
constructed in accordance with the present invention.
FIGURE 2 is an enlarged plan elevation similar to
Figure l but showing a portion only of the product.
FIGURE 3 is a cross-sectional view taken
substantially along the plane of line 3-3 of Figure 2~
FIGURE 4 is a Eurther enlarged cross-sectional
view of the product taken substantially on the plane of
line 4-4 of Figure 2.
FIGURE 5 is a side elevational view of a pulley
with the lagging product of the present invention applied
thereto.
FIGURE 6 is a cross-sectional view of a portion
of the product and pulley showing means of attachment.
FIGURE 7 is a cross-section view similar to
Figure 6 but showing an alternate means of attachment.
FIGURE 8 is a fragmentary perspective view of a
modified form of the lagging product.
FIGURE 9 is an elevationa1 view of a pulley/roll
having another form of lagging product of the present
invention applied thereto,
FIGURE l0 is an enlarged fragmentary cross-
sectional view taken substantially on the plane of line of
l0-l0 of Figure l.
FIGURE ll is a plan view of the structure
illustrated in Figure 2 as sugyested by the lines ll-ll of
Figure l0.
FIGURE 12 is an elevational view of a pulley/roll
having applied thereto a further modified form of the
lagging material.
FIGURE 13 is an enlarged fragmentary cross-
sectional view taken substantially on the plane of line 13-
13 of Figure 120
~,
-G~ ~ 7 ~ 3
1 FIG~RE 14 is a plan view of the structure
illustratecl in Fiyure 13 as indicated by lines 14-14 of
Figure 13.
FIGURE 15 is a cross-sectional view of a further
modified form of the present invention.
FIGURE 16 is a plan view of a portion of the
member shown in Figure 15,as indicated by lines 16-16 on
Figure 15.
~EST MO~ OF C~R~L~O~ r~Y~L~l9L
The lagging member 6 of the present invention is
designed for applying to the peripheral wall 7 of a belt
pulley 10, processing roll or the like, and comprises
briefly a thin flexible non-extensible sheet 9; a layer
1~ flexible lagging material 12 bonded to the normally outer
side of sheet 9; and a coating 13 of relatively soft rubber
or other similar elastomeric material bonded to the
normally underside of sheet S; and means 28 for fastening
the lagging member peripherally to the outer peripheral
surface 16 of wa]l 7 with the elastomeric layer 13 wrapped
in torsional stress supporting, mating, engagement with the
surface.
In accordance with the present invention, and as
a principal feature thereof, lagging member 6 is most
conveniently and economically molded in a rubber plant
flat, in planar, integrally bonded, laminatedr form which
may be furnished to industrial users who may cut the
members to sizes for wrapping around and fastening to the
exterior suriace of belt pulleys, processing rolls~ and the
like. In its preferred form, the interior non-extensible
sheet 9 is composed oE lightweight sheet metal which will
afford adequate tensile strength while yet being
sufficiently flexible for wrapping upon the periphery of
the pulley wall in close conformity thereto. Sheet steel
of up to about 1.6 m~m. thicknes has been found
satisfactory for the wide range of applications to which
the product has been tested~ The laminated structure
7 ~ 73~3
l comprises a relatively thick layer of lagging material 12
which is basically an elastomeric tread-like material which
is bonded to the normally outer sicle of sheet ll and a
relatively thin coating or laminae of elastomeric raaterial
5 13 bonded to the normally underside of sheet ll~ The whole
product is thus quite flexible and may be readily wrapped
upon the circular periphery of the pulley/roll. It has
been found that the lightweight metal insert will support
the fastening means, the sheer stresses to which the
product is subjected, and provide dimensional stability;
while the elastomeric undercoating 13 provides torsional
grip, relieving the load on the fastening means and only
requiring the latter to hold the rubber undercoating in
snug frictional engagement with the pulley/roll wall 7.
As a principal feature of the present invention,
the lagging member may be readily applied to the circular
pulley/roll wall by simply wrapping the member on the wall
and merely fastening the circumferentially spaced ends 17
and 18 of the lagging member. Any convenient form of
~ pinning, staplingl rivetting or welding of such ends may be
used, it being noted that the essential function of such
fastening is to secure the lagging member in a
circumferential embrace on the pulley/roll wall. ~he
elastomeric undercoating 13 will provide torsional grip and
cofunction with fastening means 28 to carry the load.
One of the discoveries of the present invention
is that the forces to which the lagging is subjected in
use, as in the driving of a conveyor belt or the like, are
primarily shear Eorces and that the pressure exerted by the
belt upon the lagging, which is backed up by the pulley
wall, retains the lagging in pressuri~ed contact with the
pulley wall. I have found that this resistance to shear is
readily obtained by the combination of the non-extensible
; member insert 9 and the bonding thereof to the inner and
outer laminas 12 and 13. As above noted, difEerent
elastomeric materials may be used in the two laminas 12 and
13, the only requirement being that the elastomeric
' ~
''3~3;~
1 materials be bonded to the interior reinforcirlg ~heet 9.
~or most purposes elastomeric material having a durometer
of about 50 to 60 shore A may be used for the laminas.
Member 9 is preferably formed of sheet metal of
about 16 to 28 gauge, so as to afford adequate tensile
strength while yet being sufficiently flexible for wrapping
upon the periphery of the pulley wall in close conformity
theretoO Other non-metallic materials may be used having
requisite non-extensible strength, bondability to the
elastomeric product, and flexibility for wrapping onto the
periphery of the belt pulley or roll. Suggested for such
use are non-extensible plastics such as phenolics, epoxy
resin reinforced with fiberglass, polycarbonates, polyester
resins, resins made from urea and formaldehyde, ABS
(acrylonitrile butadine styrene) and Rrealstic (TM~.
Member 9 is disposed within the body of the elastomeric
product offset from the center plane near the underside 11
thereof so as to provide the above described three~ply
laminate structure, viz. a relatively thick outer lagging
; 20 section 12, lamina 9 and a relatively thin bottom section
13 enyaging the pulley wall 7. The elastomeric material
making up laminas 12 and 13 may be the same, or they may be
readily seleted for best performance under different
individual applications. Preferably the rubber material in
section 13 is relatively soft so as to provide a high
coefficient of friction in its contact with pulley wall 7
and prevention of movement of the lagging product while in
service, and at the same time providing for optimum contact
with the wall in conforming to minor irregularities,
protecting the metal insert against corrosion and abrasion,
and preventing entry of materials between the lagging and
the pulley, an important protection in food processing
operations. At the same time the bottom rubber lamina 13
permanently bonded to the underside of the metal sheet,
helps to prevent kinking or creasing of the metal when
bending to conform to smaller diameter pulley surfaces. I
have found that this thin rubber backing in combination
'3733
1 with the non-extensible sheet, so long as applied in
intimate contact with the pulley/roll wall, and without
further compression, will positively lock the lagging
product against slippage on the pulley/wall surEace.
In the form of the invention illwstrated in
Figures 1-4, the lagging member is molded of a width
designed for side-by side placement of a multiplicity of
strips along the lengthwise dimension of pulley wall 7, as
seen in Figure 5, with the length of the strip extending
circumferentially of wall 7. The molded strip may be
conveniently made in relatively narrow widths, say 5-10
centimeters, and of any convenient manufacturing length
such as 300 to 1,000 centimeters or more. The product thus
dimensioned may be conveniently furnished to the user in
flat length or coiled form. The user will then cut off
from the supplied length of material a piece which has a
length corresponding to the circumference o the roll to be
covered.
In the application of the lagging product to the
pulley, it has been found that due to the il~herent
frictional characteristics of the rubber backing,
difficulty may be experienced in obtaining a
circumferentially straight alignment of the lagging strips
in tight, full face contact with the pulley wall. As
pressure is applied to the lagging to obtain a tight
contact, the rubber backing acts to prevent movement and
retains the assembly in position as first placed. In order
to obtain 100% contact between the lagging and pulley
surfaces, some adjustment of positioning of the lagging on
~he pulley is highly desired if not required. Any
deviations of the length of the lagging from a cross-
sectional plane perpendicular to the axis of the pulley
will result in a void at one edge of the lagging due to
each edge of the lagging contacting the pulley at different
radii. In order to facilitate ~he proper precise mountiny
of the lagging product on the pulley face, I apply to the
contacting surfaces a volatile liquid lu~ricant which
:Lo~ 3~
1 permits adjustment of the position of the lagging into a
precision Eit. Water, preferably with a wetting agent is
satisfactory, e.g., a 15% alcohol solution. As a feature
of the present inventionl the bottom lamina 13 is formed
with a plurality of longitudinally spaced transversely
extendin~ grooves 16 deEining longitudinally spaced
transversely extending pulley wall engaging lands 17 with
open passageways therebetween for discharging of the
lubricant applied to the wall and the underside of the
lagging and expressed from the lands 17 upon securing of
the lag~ing product to the wall.
In the form of the invention illustrated in
Figures 1-4, the user will cut a length of lagging to
correspond with the circumference of the pulley wall to be
covered. The liquid volatile lubricant will then be
applied ether to the wall or the underside of the member
and the strip laid circumferentially on the wall and
adjusted to its exact position and with its opposite ends
21 and 22 brought into opposed relation as seen in Figure
6~ Preferably a banding means 23, see Figure 5, is applied
to the strip for circumferentially compressing the strip on
the pulley wall so as to obtain 10~% face-to-face contact.
In this operation, excess lubricant will be squeezed into
the grooves 16. A standard strapping tool may be used such
as Band-It ~TM), Punch-Lock (TM) or chain-type vice grip.
Tightening of the clamp is effected while the lagging is
movable and lubricated. The pattern of grooves 16 and
lands 17 also provide a series of sharped edged squeegy
contacts which further enhance the gripping ability of an
otherwise smooth rubber backing to the pulley surface.
Additionally~ it has been found advantageous to
apply to the peripheral surface o~ the pulley/roll, a
coating for protecting the surface against rust and
corrosion and also to improve the frictional grip of the
elastomeric layer 13. A latex-type paint such as used for
undercoating on automotive vehicles is very satisfactory.
A neoprene water solutioll as sold by Neoprene International
~ 3
1 Corporation, Glen Ellyn, Illinois/ is an excellent material
for this use, The latex-base paint sets up hard~
s~bstantially tack-free, seals the pulley/roll surface
against rust and corrosion, and cofunctions with the rubber
backing to securely hold the lagging member in place.
A6 a feature of the present invention, the strip
width of the lagging product is confined to a manageable
width for precise mounting on a pulley wall and for full-
face intimate contact against the pulley wall by the clamp
member 23. At the same time the relatively narrow width of
the lagging strip permits the ready disposition of a
plurality of strips across the longitudinal dimension of
the pulley as seen in Figure 5. The user may thus readily
select the amount of pulley surface to be covered. In many
instances it is only necessary to cover 60 to 70% of the
pulley surfaces. Circumferential grooves around the
finished pulley may thus be easily provided for taking away
water, mud or other products being transported by a belt
entrained around the lagging; and one or more of such
grooves may also be used as a guiding channel for a V-belt
or the like.
; Securement of the lagging strips is here effected
by fastening the opposite ends 21 and 22 of the lagying
strip to the pulley wall or to each other as seen in
Figures 5, 6 and 7. Thi.s may be done by means pinning the
opposite ends 26 and 27 of member 9 to the pulley wall 7 or
to each other by riveting, stapling, bolting or welding.
As seen in Figure 6, the outer lagging lamina 12 is cut
back to expose the opposite ends 26 and 27 o member 9 and
these ends may then be ~onveniently pinned by rivets 28 to
the pulley wall as illustratedO They may also be pinned
down by spot welding to the wall with the same result.
Another form of fastening o~ the lagging is illustrated in
Figure 7, where the opposite ends 26a and 27a of ~ember 9a
are brought into overlapping position and pinned together
by one or more rivets 28a. Here again, the overlapping
ends 26a and 27a could be suitably crimped or spot welded
-12~ 97~3
1 together. The width of the surrounding clamping band 23
may be substantially less than the width o the elastomeric
strip, as seen in Figure 5, and still provide full
compressive holding of the strip to the pulley wall.
Accordi~gly, ample room is left on opposite sides of the
band for placement of rivets 28 or for spot-welding or the
like~ Where riveting is used, the internal reinforcing
member 9 eliminates fastener pull~through problems.
A modified form of the invention is illustrated
in Figure 8 of the drawings, wherein the product is
composed of a broad, flat sheet 31 of flexible elastomeric
material and a plurality of flat~ elongated, thin, flexible
metal or other non-extensible members 9a mounted in
substantially co-planar, parallel, laterally spaced apart
and longitudinally coterminous position in a mid~plane of
sheet 31 and bonded integrally thereto so as to provide a
relatively thicls outer lagging section 12a and a relatively
thin protective and wall gripping undercoating 13aO The
latter as in the first described embodiment is formed with
a plurality of longitudinally spaced, transversely
extending grooves 16a for discharge of above described
lubricant/adhesive; although the use of a lubricant is not
as critical in this form of the invention. As an important
feature of this construction, the sheet is readily
severable between the members 9a to provide a plurality of
elastomeric strips similar to strip 8 hereinabove
described, that is of a width designed for side-by-side
placement of a multiplicity of such strips along the
lengthwise dimension of the pulley wall, the strips being
severable transversely to desired length for wrapping upon
and securing to the pulley wall with the length of the
strip extending circumferentially of the wall as
hereinabove explained, The product as illustrated in
Fiyure 8 may be economically produced in large sheets in a
3~ molding press. Lateral`spacing between the reinforcing
members 9a permits readily slicing of the elastomeric
material between the members to provide the desired
~,
~3~ 33
1 longitudinal strips. To facilitate the slicing of the
sheets into the individual strips, the outer, thick,
elastomeric section 12a may he formed with a plurality of
longitudinally extending slits 32 which are aligned
longitudially with the spaces between members 9a and extend
midway into the outer section 12a to make easy and precise
the cutting through of the elastomeric material.
Various tread-like suraces may be molded into
the outer side of lagging section 8 to provide a rubber-
like tread, non-slip characteristics, and to facilitate
processing operations, e.g. rice hulling, lumber feed
rolls, nut processing, sheet steel conveying, etc~ Lorig-
type grooves may be similarly provided. Since the strip is
applied to the pulley or roll in a circumferential plane
perpendicular to the axis of rotation, the lagging is bi-
directional enabling the pulley or roll to be driven in
either of its opposite directions with equal effect and
performance,
Another advantage of the present lagging is the
ease in which step crowning of the pulley may be
accomplished to improve belt training by simply applying to
the pulley over the central section thereof one or more
lagging strips of greater thickness than the strip~ applied
to the opposite end portions of the pulleyO A step crowned
pulley will have about 60% of the center section raised,
and about 20~ at each end of the pulley lowered, the step
ranging about 1.6 mm or more.
As a special feature of the forms o-E the
invention shown in Figures 9-16 the fastening of the
circumferentially spaced edges ~-lb and 22b may be easily
and effectively accomplished by welding these ends to the
pulley/roll periphery where the latter is of conventional
steel construction. Welding apparatus and experience is
~ most commonly available in industrial plants which will
; 35 make use oE the lagging product and will many times be the
fastening means of choice There is another and important
advantage in welding the ends of the lagging product to the
7~l~
1 pulley/roll periphery in that the welding process, as a by-
productl produces a heating and expansion of the metal at
the time of attachment and thus provides upon ensuing
cooling and contraction a tightening of the elastomeric
laminate 13 onto the peripheral pulley/roll surface 16.
While the welding of the lagging member ends may
frequently be the attachment of choice, the internal
stabilizing sheet 11 is required to be only of a light
gauge, as above explained, and in its preferred form is too
light for normal weldingO Accordingly, and as a further
feature of the present invention, separate members 31 and
32 of weldable weight metal are mounted at the
circumferentially spaced edges 21b and 22b. In the forms
of the invention shown in Figures 1-6, these members
comprise channels having opposed side walls 43 and 44 and
connecting wall 45 which may be mounted in surrounding
relation to ends 21b and 22b so as to tightly grip within
each channel the bonded laminate comprising sheet 9b and at
least some elastomeric product on opposite sides thereof.
Thus the channel members provide a complete and effective
seal for the circumferentially spaced edges of the lagging
product, protecting the interior metal sheet against rustr
corrosion or other deterioration. To enhance this Eeaturer
channels 31 and 32 are preferably formed of stainless
steelO
In the application of the lagging member to the
pulley/roll, the lagging member is cut to a length
corresponding to the circumference of the pulley/roll. The
relatively thick lagging 12b is preferably reduced in
thickness adjacent ends 21b and 22b, using an appropriate
cutting tool, so as to provide an overall thickness which
will it snugly within channels 31 and 32. The channels
may then be clamped onto the ends by any suitable means.
Indenting or deforming one or both of channel walls 43 and
44 will accomplish the desired purpose. This may be done
with a simple indenting punch, the results of which will be
noted in the drawings where one side of each of the
-lS~ ~ 7~3
1 channels is jointly deformed with the interior ~heet 9b
into one of the adjacent laminae, here laminae 13b.
The lagging member formed as above may then be
wrapped around the pulley/roll periphery as above
described. A bead of welding material 46 may then be
placed at the confronting ends of the channels and the
pulley/roll surface 16. The lagging member ends may be
brought quite close together as here shown or may be
somewhat further apart and separately welded as suits the
convenience of the user. Spacing between the confronting
edges will be typically up to about one centimeter or more.
A further modified form of the invention is
illustrated in Figures 12-14 wherein the lagging member 6c
is especially formed for mounting longitudinally of
pulley~roll 7c. In this case the integrally molded
laminated structure comprises the same interior ~etal sheet
9c, relatively thick outer layer 12c of lagging material
and relatively thin interior layer llc of elastomeric
material, the product being molded flat in any desired
~ convenient and economical length. Since the circumferen-
tially spaced edges 17a and 18a will extend along the
longitudinal sides of the molded strip, these sides may
readily be molded to provide margins of reduced thickness
of the lagging material 12c so as to provide preformed edge
sections which will fit within channels 21a and 22a. The
latter may be secured to these margins by indenting or
otherwise as hereinabove explained. In the application of
this form of the invention, the lagginy material is cut to
a length corresponding with the axial length or face width
of the pulley/roll. I have found it convenient to weld one
of the longitudinally extending channels to the peripheral
wall 7c of the pulley/roll with the welded edge and weld
beads 46a extending parallel to the axis of the
pulley/roll. The product will tend to stand off
tangentially from surface 7c but is sufficiently flexible
to readily flex into wrapping relation around surface 16a
by the use of any simple banding of holding tool. The
~.
-16~ 33
1 oppo~ite edge channel may then be welded to surface 7c to
fasten the lagging in place. Additional lagging members
may be similar]y fastened to the pulley/roll periphery,
covering such portion of the circumference as desired. By
accurate spacing of the lagging members, more perfect
balance can be achieved, as contrasted to prior art
lagging.
A further modified form of the invention is
illustrated in Figures 15 and 16 wherein the lagging member
6d is especially formed for mounting longitudinally of the
pulley/roll similar to the embodiment of Figures 12-14. In
this case the circumferentially spaced edges 17b and 18b
will extend along the longitudinal sides of ~he member and
thus readily accommodate within the mold, extra pieces 31a
and 32a of heavier gauge, weldable weight, sheet metal. In
accordance with the present invention, these members are
first cut in strips having a length equal to the length of
the interior metal sheet 7d, and the strips 31a and 32a are
positioned upon and tack-welded or otherwise secured to the
longitudinal margins of sheet 7d to extend laterally
therefrom prior to the mounting of sheet 7d and attached
strips 31a and 32a into the mold for molding of the
exterior lagging 12d and the interior elastomeric layer
13d. These weld strips 31a and 32a may conveniently by
fabricated from sheet steel of about 14 to 16 gauge and may
be readily attached to sheet 7d by continuous electric
resistance or spot welding. Where the lagging is to be
used in an acid or corrosion-prone environment, the welding
strips may be made of stainless steel. Also preferably the
strips 3~a and 32a are given a slight concavo~convex form
so as to more readily engage the curved pulley/roll
periphery for welding at the contacting edges of the
strips. As will be understood, the light-gauge metal sheet
7d and the elastomeric members 12d and 13d permit ready
flexing for wrapping the lagginy member onto the
cylindrical pulley/roll periphery as in the earlier
described embodiments.
,,~
