CA1200177A - Shipping and installation straps for linear actuators - Google Patents

Abstract

Abstract:

A disposable rupturable shipping and installation strap (30, 130) holding in a retracted position the output member (22, 122) of a linear actuator (14, 114) such as a pre-filled hydraulic actuator (14, 114). The strap has a retaining member (54, 70, 94, 138) fitted over the end of the actuator output member and a pair of symmetrically disposed strips or bands (48, 50, 72, 148, 182) integrally formed with the retaining member and attached at their other end to a portion of the actuator housing (14, 114). The strips or bands have portions of reduced strength (58, 158) which cause the strap to break and free the actuator output member Upon first operation of the actuator. Preferably the strap is molded of relatively thin flexible plastic.

The retaining member is preferably in the form of a cylin-drical cap (94, 138) installed on the end of the actuator output rod and having a substantially hemispherical end portion (166) engaged in a corresponding partially spherical concave recess (139) in the member operated by the actuator, such as a motor vehicle clutch release lever (128). The cylindrical cap is optionally provided with a radially extend-ing disc-like flange seal (190) resiliently engaged with the surface of the clutch actuating lever beyond the edge of the recess, such as to prevent introduction of dirt in the recess.

Description

Shippin~ and Installation Straps_for Linear Actuators ~e present invention relates to an apparatus and method for shipping and installing a linear actuator. More particularly, the present invention relates to shipping and installation straps for holding in a retracted position the output member of a linear actuator, such as a hyàraulic actuator, during transportation and storage and during installation of the actuator for operation of a mechanism.

llydraulic actuator apparatus are known for operating a mech-anism at a remote location by way of a master cylinder, for example, connected to a slave cylinder installed at the remote location. ~ conduit interconnects the master cylinder to the slave cylinder, and the hydraulic apparatus is filled with hyclraulic fluid such that when the piston of the master cylinder is actuated, the piston of the slave cylinder, and consequently the piston rod or output member of the slave cylinder, is simultaneously actuated by displacement of the hydraulic fluid from the master cylinder to the slave cylinder through the conduit.

~lore particularly, it is known to provide such hydraulic apparatus for operating, for example, the release mechanism oE a ~riction clutch. As disclosed in British pa-tent speci-fication 1,539,879, it is also known to pre-assemble friction clutch hydraulic release apparatus, by filling with hydraulic fluid the master cylinder, the slave cylinder, the conduit interconnecting the cylinders and a reservoir connected to the master cy]inder, and bleeding the system before shipment of the assembly to a motor vehicle manufacturer, for instal-lation on a motor vehicle. Preferably, the hydraulic apparatus is filled with fluid maintained by a resilient diaphragm disposed in the reservoir of fluid, at a pressure slightly higher than atmospheric pressure to prevent ,~ ,., ' ~ p~

introduction o at:mospheric air into the system during transportation, storage and installation. Pxior to instal-lation, the piston rod, or output member, projecting from one end of the slave cylinder may become extended such that the over-all length of the slave cylinder, with the piston rod extended, may occupy more space than necessary in the shipping container, the rod may become bent or damaged while in transit or storage or become disconnected from the piston, the pressure of the fluid may drop below atmospheric pressure, thus causing air to be introduced into the hydraulic appar-atus and the slave cylinder piston rod must be manually retracted, and held retracted during installation of the apparatus in the motor vehicle.

me principal object of the present invention, therefore, is to provide a restraining strap for the output member of a linear actuator such as the piston rod of a slave cylinder of a pre-filled sub-assembly comprising a mastèr cylinder, a slave cylinder and a conduit interconnecting the maste~r cylin-der with the slave cylinder. The object of the invention is achieved by providing a flexible, preferably plastic, strap having a portion maintaining the slave cvlinder piston rod in a retracted position by attaching the end oE the piston rod to the housing of the slave cyllnder, the strap having appropria-te weakened break-a~ay sections deEining one or more rupture portions, such that when the piston of the master cylinder is actuated for the first time, thus causing a thrust to be applied to the piston and piston rod oE the slave cylinder, the strap is broken and the apparatus is enabled to operate in a normal manner.

Another object of the present invention is to provide a shipping and installation restraining strap more particularly for the piston rod of a slave cylinder adapted to operate a motor vehicle clutch re].ease mechanism having a recess re-ceiving the end of the piston rod, and to provide a separate or separable nosepiece for the slave cylinder piston rod end forming a bearing ~ember interposed between the rod end and the surface of the recess, and arranged such that the nose-piece is made integrally with or attached to the bands or strips of the restraining strap.

A further object of the invention is to provide the bearing-nosepiece with an integral seal member preventing introduc-tion of dirt between the bearing surface of the nosepieceand the surface of the recess in the clutch actuating member.

These and other objécts and advantages of the present inven-tion will become apparent to those skilled in the art when the following desc.ription of examples of the best modes con-templated for practicing the invention is read in conjunctionwith the accompanying drawing wherein:

FIG. 1 is a schematic illustration of a hydraulic apparatus having a slave cylinder, shown partially in section and provided with an example of structure for a shipping and installation restraining strap according to the present invention;

FIG. 2 is a partial vi.ew similar to FIG. 1, but showing the broken strap ater the first operation of the appara-tus;

FIG. 3 is a front elevation view from line 3-3 of FIG. l;

FIG. 4 is a side elevation view of the restraining strap of FIGS. 1-3;

FIG. 5 is a plan view thereof as seen from lines 5-5 of FIG. 4;

'7~7 FIG. 6 iS a partial view similar to FIG. 1, but showing a modification of the restraining strap according to the present invention;

FIG. 7 is a view similar to FIG. 6, but showing the conditi.on of the strap after operation of the slave cylinder;

FIG. 8 is a side elevation view of the example of strap of FIG. 6;

FIG. 9 is a plan view thereof;

FIG. 10 is a view similar to FIG. 6, but showing a fur~her modification of a restraining strap accoxding to the present 1nventlon;

FIG. 11 is a view similar to FIG. 10, but showing the condi-tion of the strap after operation of the slave cylinder;

FIG. 12 is a view similar to FIG. 6, but showing another modification of a restraining strap according to the present invention;

FIG. 13 is a view slmilar to FIG. 12 but showi.ng the condi-tion of the strap after operati.on of the slave cylinder;

FIG. 14 iS a side elevation view o the restraining strap of FIG. 12;

FIG. 15 i.s a rear elevation view thereof as seen from line 15-15 of FIG. 14;

FIG. 16 is a schematic illustration of a hydraulic slave cylinder provided wit~ another example of structure for ~f~

shi.pping and installation restraining strap according to the pre,sent invention and shown partially in section;

FIG. 17 is a cross-section from line 17-17 of FIG. 16;

FIG. 18 is a partial section from line ls-la of FIG. 16;

5 FIG. l9 is a partial view similar to FIG. 16 but showing the broken strap after the first operation of the apparatus;

FIG. 20 is a side elevational view of the restraining s-trap of FIGS. 16-19;

FIG. 21 is a plan elevation view thereof from line 21-21 of lO FIG. 20;

FIG. 22 is an eleva-tion view, with portion broken away, of the rod end nosepiece associated with the .restraining strap of FIGS`.- 20-21,-FIGS. 23 and 24 are respectively front and rear views of the15 nosepiece of FIG. 22;

FIG. 25 is a partial view similar to FIG. 16 but showing a modiication of the restraininy strap accordi.ny to the present invention;

FIG. 26 is an exploded perspective view of the restraining strap of FIG. 25;

FIG. 27 is a view similar to FIG. 16 but showing a modifica-tion of the invention providing a combination restraining strap nosepiece and seal;

FIG. 28 iS a partial section along line 28-28 of FIG. 27;

FIGS. 29-31 are respectively side elevation views with por tion broken away, and front ana rear views of the nosepiece of FIG, 27;

5 FIG. 32 is a view similar to FIG. 25 but showing a ~urther modification of the invention;

FIG. 33 is a side elevation view of the restraining strap of FIG. 32; and FIG. 34 is a rear elevation view thereof.

Referring now to the drawing and more particularly to FIG . 1, there is schematically illustrated a hydraulic apparatus assembly 10 comprising a master cylinder 12 hydraulically interconnected to a slave cylinder 14 by means of a conduit 16, in the form of a flexible hose, for e~ample. After assem-bly of the diverse components, the whole appara-tus is filled with a hydraulic fluid under slight pressure and bled to remove air from the apparatus by way o a bleed valve 18, mounted for example on the slave cylinder 14j until all air has escaped ~rom the apparatus. ~lternatively,~ atmospheric air is evacuated from the apparatus and the apparatus filled with hydraulic fluid at a pressure slightly higher than atmospheric pressure.

An additional reservoir o~ hydraulic fluid, not shown, is connected to the master cylinder 12. The reservoir of hydraulic fluid may ta~e the form of a built-in reservoir integral with, or directly attached, to the master cylinder housing, or it may be a remotely located reservoir connected by a conduit to the master cylinder 12. The hydraulic fluid is maintained during transport, storage and installation at t~

a pressure sligh tly higher than atmospheric pressure by an accumulator consistin~, for example, of a resilient dlaphragm disposed in the fluid reservoir.

As is well known, any displacement of the master cylinder 5 piston rod 20 causes a corresponding displacement of the piston rod or actuator 22 of the slave cylinder 14, as a result of transferring a portion o the hydraulic fluid from the master cylinder 12 through the conduit 16 to the slave cylinder 14. The piston rod 20, or input member, of the 10 master cylinder 12 may be operated, for example, by the clutch release pedal 24 of a motor vehicle, the master cylinder 12 being installed, for example, below the floorboard of t:he motor vehicle driver compartment, the slave cylinder 14 L~eing attached on the wlderframe of the vehicle in an appropriate 15 position such that the end of its piston rod 22 actuates the release mechanism 26 of the motor vehicle friction clutch t not shown.

During assembly of the slave cylinder 14, a shipping and installation strap 30 is installed, according to the present 20 invention, such as to restrain the slave cylinder piston rod - 22 from extending beyond a certain limit rom the open end 31 of the slave cylinder housing 32, E'IG. 2. An elas-tomeric hellows boot 34 has an end affixed to the rim of tlle cylinder housin~ 32 and another end elastically engaging a portion of 25 the peripheral surface of the piston rod 22 for the purpose of protecting the covered portion of the piston rod 22 from the all~bient and preventing introduction of foreign matter and dirt into the open end 31 of the cylinder housing 32 through ~hich the rod 22 projects. In the structure illu-30 strated, the end of the rod 22 projecting from the slavecylinder housing 32 has a hemispherical portion 36, provided with a reduced diameter coaxial projecting pin-like member 38 for en~agement and centering with the end of the clutch release mechanism 26. The other end of the rod 22 has a hemispherical enlarged portion 37 freely engaged in a corre-sponding -tapered hemispherical recess 38 formed at the bottom of the slave cylinder piston 41.

The slave cylinder housing 32 is provided with a peripheral annular flange 40, and the strap 30 has a corresponding annular flange collar 42, comprising an annular flange 43 formed on one side of a cylindrical rim 44 fitting over the housing annular flange 40, the strap annular flange 43 forming an opening 46, FIGS. 4 and 5, fitting over the slave cylinder housing 32. A pair of diametrally disposed bands or stxips 48 and 50 are heat-welded to, or molded integrally wlth, the rim 44 of the flange collar 42 at one of their ends and pro-vided with a nosepiece or retaining men~er in the form of a partially spherical cup member, 52 and 54 respectively, at their other end.~ The strap 30 is preferably molded of~plastic-such as a polyamide (nylon), and the bands or strips 58-50 are relatively flexible. m e strap 30 is molded in the shape illustrated at F:~GS. 4 and 5, i.e. with a pre-formed bend 56 proximate the end of each band or strip 48 or 50 joined to the rim 44 of the flange collar 42. ~le o-ther end of each band or strip 48-50 is providea wi-th a`weakened portion 58 where it is integrally rnolded with the partially spherical cup member 52-54, each weakened portion 58 being in the form of a reduced thickness portion as shown at 60, resulting from a surface groove, most clearly shown at FIG. 4, or a reduced width portion, as shown at 62 at FIG. 5, or both.

The partially spherical cup members 52 and 54 are each pro-vided with a central aperture 64 through which passes the pin-like projection 38 on tlle piston rod end 36, when the strap 30 is installed during assembly of the apparatus in the posi~ion ill~strated at FIG. 1, with the partially spher-ical cup members 52 and 54 disposed over the hemispherical end 36 of the piston rod 22, such as to maintain the piston rod 22 in a retracted and centered position.

After installation of the hydraulic apparatus 10 in a motor vehicle, the first time the clutch release mechanism is actuated by operating the clutch pedal 24, hydraulic fluid is supplied from the master cylinder 12, when the piston rod 20 of the master cylinder is reciprocated, to the slave cylinder 14 through the line or conduit 16, such that the slave cylinder piston rod 22 is extended, for example to the posi-tion sllown at FIG. 2. Although the weakened portions 58 of the bands or strips 48-50 of the strap 30 are capable of holding the slave cylinder piston rod 22 in its retracted and centered position during shipping, storage and installation of the hydraulic apparatus 10 in a motor vehicle, the force exerted on the slave cylinder piston 41 during the first operation of the clutch release causes the strap bands or strips 48 and 50 to break away from the C~lp members 52 and 54, respectively, when the piston rod 22 is extended~ thus subsequently permitting normal operat.ion of l:he hydraulic apparatus 10.

Although the strap 30 may be molded of any convenient flexible plastic, polyamide plastic such as nylon type 6/6, for example sold by E. I. DuPont de Nemours & Co. under the trademark Zytel has been found particularly convenient/ the strap bands or strips 48 and 50 having a thickness, for example of 0.6 to 1 mm, and a width of 8 to 12 mm., with a break-out groove 60 0.15 to 0.3 mm. in depth and/or a reduc-tion in width of each band or strip at the junction with the cup members 52 and 54, as shown at 62 at FIG. 5~ being --slightly more than one-half the width of the bands or strips themselves.

t~?-7 The presellt invention is susceptible of various modifications for accomplishing its objects of conveniellce of shipping and installation of pre-filled hydraulic apparatus. An example of such modification is illustrated at FIGS. 6-9 wherein a shipping and installation strap 30a is illustrated as com-prising a single cup-shaped piston rod reta;ning member 70, disposed over the end 36 of the piston rod 22 of a slave cylinder 14, FIG. 6, provided with diametrally disposed bands or strips 7~ each having an integral strut 74 formed on the end thereof, substantially at right angle to the axis of each band or strip. The inner end of each strut 74 is.introduced in a receiving recess 76 formed in an annular flange 78 disposed proximate the end of the slave cylinder housing 32.
A weakened portion 58 in the form of a break-away groove, as shown at 80, is formed at the junction between the other end of each band or strip 72 and the cup-shaped retaining member 70 such that, when hydraulic flui.d is fed to the slave cylin-der 14, thus causing its piston rod 22 to extend, the bands or strips 72 separate at the ~eakened portions 58 from the cup-shaped retaining member 70 and free the piston rod 22 for normal operation, as illustrated at FIG. 7.

In such an arrangement, with the struts 74 relatively loosely fitted in the receivi.ng recesses 76 in the slave cylinder annular flange 78, after the bands or strips 72 become separated from the cup-shaped retaining member 70 in the course of the first rel.ease of the motor veh;.cle friction clutch, which generally occurs at the end of the assembly llne, the bands or strips 72 generally drop off. If they remain attached to the slave cylinder housing, they do not interfere with normal operation of the clutch.

At FIGS. 10-11 there is illustrated a further modification 30b of a shipping and installation s-trap according to the present invention for restraining and centering the output 3~

member of a linear actuator, such as the piston rod 22 of a slave cylinder 14, in its retracted position ul~til the linear actuator or slave cylinder, is first operated. The restraining strap 30b is substantially alike the strap 30a of FIGS. 6-9, 5 the bands or strips 72 being, however, provided on their free end with a lug 82 snapped through an aperture 84 disposed in a ring such as the metallic ring 86 slipped over the cylinder housing 32 and adapted to engage an annular flange 88 on the peripheral surface of an end of the housing 32~
10 t~lhen fluid is first applied, after installation of the hy-draulic apparatus, to the slave cylinder 14, causing the piston rod 22 to extend, the weakened portion 58 formed by the break-away groove 80 at the junction between the bands or strips 72 and the cup-shaped retaining member 70 causes the 15 bands or strips 72 to separate from the retainin~ member, as shown at FIG. 11, thus permitting the piston rod 22 to operate in the usual manner. The loose bands or strips 72 also generally fall off during first operation of the hydraulic apparatus.

20 It will be appreciated by those skilled in the art that the retaining members 52-54 and 70 of the straps 30, FIGS. 1~5, 30a, FIGS. 6-9, and 30b, FIGS~ 10-11, are adapted to restrain and center the end of a linear actuator output member, such as the piston rods 22 provided with a hèmispherical portion 25 3G, whether or not the hemispherical portion 36 has a reduced diameter coaxial projecting pin-like men~ber 38. The strap retaining mer[bers 52-54, FIGS. 1-5, and 70, FIGS. 6-11, do not interfere with the operation of the clutch release mechanism, and they may eventually wear out or fall off 30 without affecting the operation of the clutch release mech-anism.

A modified restraining and centering shipping and installa-tion strap, as represented by the example of strap -30c of FIGS. 1~-15, is particularly adapted for retaining and 35 centering the output member of a linear actuator such as the s~

slave cylinder pîston rod 22, FIG. 12, having a cylindrical end 90 provided with a flat end face 92.` The strap 30c is substantially alike the strap 30a of FIGS. 8 and 9, i.e. having a pair of bands or strips 72 terminating each at one end in an integrally molded strut 74, subs-tantially at right angle to the axis of each band or strip, having a portion introduced in a receiving recess 76 in the annular flange 78 formed proximate the end of the slave cylinder housing 32, FIG. 12. The strips or bands 72 diametrically project from the edge of a substantially hemispherical retaining member 94, integrally molded therewith and joined thereto by way o weakened portions 58 each in the form of a groove 80. The substantially hemispherical retainer member 94 has coaxial blind bores 96 forming a bottom surface 98 against which abut the end face 92 of the rod cylindrical end 90, ~Then the strap 30c is installecl with its retaining member 94 placed over the end 90 of the rod 22, the rod cylindrical end 90 being introduced into the retaining member bore 96. The retaining member bore 96 is preferably provided with a plurality of longitudinal grooves 100, best shown at ~IG. 15, for aid in installation of the restraining strap 30c to allow air or oil to escape from the bore 96 when the retaining member 94 is pushed over the rod end 90.

When the slave cylinder 14 is first operated, the bands or strips 72 separate or break away from the substantially hemispherical retaining member 94 at the surface grooves 80 forming the weakened sections 58 of the strap. In the struc-ture o:E FIGS. 12-15, the substantially hemispherical retaining men-ber 94 is molded with a substantial wall thickness, and remains in position, as shown at FIG. 13, during operation of the clutch release mechanism. The peripheral surface of the retaining member 94 actually forms a spherical bearing inter-posed between the flat end face 92 of the piston rod 22 and the end of the clutch release control member 26.

3~ 7 ~eferring now to FIG. 16, there is illustrated a slave cylinder 114 having a housing 132 atkached to a bracket 135, or other member, forming part of the clutch bell housing or transmission housing, not shown. The end 136 of the slave cylinder piston rod or actuator 122 is engaged in the central bore 137 of a separate nosepiece 138 forming a bearing member between the rod end 136 and a generally hemispherical recess 139 in the clutch release lever 128. A strap 130, together with the nosepiece 138, forms a restraining means for the piston rod or actuator 122.

m e slave cylinder housing 132 is provided with a peripheral annular flange 140, and the strap 130 has a corresponding annular flange collar 142, FIGS. 1~ and 21, comprising an annular flange 143 formed on one side o a cylindrical rim 144 fitting over the housing annular flange 140, the strap . .
annular flange collar 142 forming an opening 146 itting over the slave cylinder housing 132. A pair of diametrally disposed bands or strips 148 are molded integrally with the annular flange 143 at one of their ends and provided with an integral bar or strut member 150 at their other end. The strap 130 is preferably mo]ded of plastic such as a pol~amide (nylon), and the bands or strips 148 are rela-tively flexlble. The strap 130 is molded in the shape illustr~ted at FIGS. 20 and 21, i.e. with a pre-~o~ned bend 152 p1-oxin~ate the end of each band or strip 148 joined to the rim 144 of the annular flange collar 142. Preferably, a plurality of small projecting nibs 154 are formed on the inner surface of the cylindrical rim 144 for providing a relatively tight elastic fit of -thc cylin-drical rim 144 of the annular flange collar 142 over the slave cylinder flange 140. The other end of each band or strip 148 is provided with a weakened portion 158 where it is integrally molded with the bar or strut member 150, each weakened portion 158 being in the form of a reduced thickness 7'7 portion as shown at 160, resulting from a surface groove, most clearl~ shown at FIG. 20l or a reduced width portion, as sllown at 162 at FIG. 21, or both.

The nosepiece 138, as best shown at FIGS. 22-24, is in the form of a cylindrical cap having a generally cylindrical body 164 provided on one end with a generally hemispherical face portion 166 and on the other with a flat annular end face 168 through which is disposed the bore 137. The bore 137 is pro-vided with a plurality of longitudinal grooves 170 on its surface, such as to facilitate introduction therethrough of the end 136 of the slave cylinder piston rod 122, the bore 137 terminating in a flat surface 172 against which the face o the end 136 of the piston rod 122 normally engages when the nosepiece 138 is installed over the piston rod end. A
pair of s~mmetrically disposed bifurcated ears 174 integrally radially project from the cylindrical body 164 of the nosepiece 138 proximate the annular end face 168 thereof, and each bifurcated ear 174 is provided with a partially cylindrical notch 176 forming a hook for attachment thereover of the bar or strut member 150 at the end of each band or strip 148, the reduced width portion 162, for exc~lple, of the band or strip 148 being disposed within the bifurcation gap 177 of each bifurca-ted ear 174, as shown at FIGS. 16 and 17. The nose-piece 138 may be made of the s~le Material as the strap 130, or of a different material and, if so desired, it may be made of metal. ~hatever the material used for making the nosepiece 138, it is so dimensioned that its hemispherical end face 166 fits within the partially spherical recess 138 in the clutch release lever 128, such as to provide a generally swivelling 3~ connection between the slave cylinder piston rod 122 and the clutch release lever 128. The swivelling connection compensates 3~

for relative inaccuracy in alignment of the diverse elements, and allows pivoting of the clutch release lever 128 during operation of the clutch mechanism, the hemispherical end face 166 of the nosepiece 138, and the partially spherical recess 139 co-operating for forming a ball and socket bearing arrangement between the end 136 of the piston rod 122 and the clutch release lever 128.

After installation of the hydraulic apparatus in a motor vehicle, the first time the clutch release mechanism is actuated by operating the clutch pedal, hydraulic fluid is supplied from the master cylinder, when the piston rod of the master cylinder is reciprocated, to the slave cylinder 114 through the line or conduit 116, such that the slave cylinder piston rod 122 is extended. Although the weakened portions 158 of the bands or strips 143 of the strap 130 are capable of holding the slave cylinder piston rod 122 in its retracted and centered position during shipping, storage and installation of the hydraulic apparatus in a motor vehicle, the force exerted on the slave cylinder piston during the first operation of the clutch release causes the strap bands or strips 148 to break away from the bar members 150, FIG.
19, when the piston rod 122 is extended, thus subsequentl~
permitting normal operation of the slave cylinder 114.

An example of further modification of the invention is illu-strated at FIGS. 25-26 wherein a shipping and installation strap 130a is illustrated as comprising a ring 178 disposed over a separate cup-shaped piston rod retaining member or nosepiece 138a placed over the end 136 of the piston rod 122 of a slave cylinder 114, FIG. 25. The cylindrical body por-tion 164 of the nosepiece 138a has a radially extending annular flange 180 engaged with the rear of the ring 178.
The ring 178 is provided with diametrally disposed bands or strips 182 each having an integral strut 184 formed on the ~,~s)~

end thereof, substantially at right angle to the axis of each band or strip 182. The inner end of each strut 184 is introduced in a receiving recess 186 formed in the annular flange 140 disposed proximate the end of the slave cylinder housing 132. A weakened portion 158, for example in the form of a break-away groove, is formed at the junction between the other end of each band or strip 182 and the ring 178 such that, when hydraulic fluid is fed to the slave cylinder 114, thus causing its piston rod 122 to extend, the bands or strips 182 separate at the weakened portions 158 from the ring 178 and free the cup-shaped nosepiece 138a, and consequently the piston rod 122, for normal operation.
It can be seen that in this modification of the invention, the nosepiece 138a also acts as the ball portion of a ball and socket bearing member interposed between the end 136 of the piston rod 122 and the clutch release lever 128 provided with a generally hemispherical recess 138 engaged by the hemispher-ical end 166 of the nosepiece 138a.

The structure illustrated at FIG. 27 comprises a retaining strap 130b identical to the restraining strap 130 of FIGS
16-21 combined with a modified nosepiece 138b having a disc-like sealing member 190 integrally formed therewith and projecting in a flange-like fashion from the cylindrical body portion 164 of the nosepiece 138b, and provided with a toroidal integral rim 192. ~s best shown at FIGS. 29-30, the disc-like sealing member 190, in a relaxed state, is slightly dished towards the hemispherical end face 166 of the nosepiece 138b, such that when the slave cylinder 114 is installed in a motor vehicle for actuating the clutch release lever 128, 3Q FIGS. 27-28, the toroidal rim 192 is urged in engagement with the surface of the clutch release lever 128 around the peri~
meter of the generally hemispherical recess 139 in which is engaged the hemispherical end face 166 of the nosepiece 138b.
The disc-like sealing member 190 thus~forms an effective seal ~3Lo~ 77 preventin~ the introduction of dirt from the ambient and the surroundings between the bearing surfaces formed by the surface o the hemispherical end face 166 and the generally hemispherical recess 139, which could cause rapid wearing of the bearing surfaces in engagement.

As illustrated at FIGS. 32-34, restraining straps of the type disclosed herein, that is comprising a nosepiece, such as the nosepiece 138c, formed integrally with the strap 130c, may also be provided with a disc-like sealing member 190 formed integral with the nosepiece 138c and radially projecting from the cylindrical body portion 164 of the nosepiece. In the struc-ture illustrated at FIGS. 32-34, the retaining strap portion 130c of the integral assembly has the general structure com-prised of bands or strips 182 provided at an end each with a 14 strut 184 enga~ed in an appropriate recess 186 in the flange 140 of the slave cylinder housing 132. The other end of each band or strip 182 is integrally attached to the nosepiece 138c by a weakened portion 158, for example in the form of a reduced width portion, such as to readily separate from the nosepiece upon first actuation of the slave cylinder 114.
After separation of the nosepiece 138c from the bands or strips 182, the nosepiece acts as a bearing member interposed between the end 136 of the piston rod 122 and the recess 139 in the clutch release arm 128, the flexible disc-like sealing member 190 frictionally sealing the bearing suraces against any dirt from the surroundings.

It will be appreciated by those skilled in the art that the present invention, although disclosed for illustrative pur-poses in specific structures in conjunction with a specific hydraulic apparatus, has many practical applications in ship-ping and installing diverse linear actuators of any form whatsoever wherein it is desired to restrain against displace-ment the actuator output member until after installation, and -1.8-to free the output member for nol~nal operation upon first actuation.

~aving thus described the present invention by way of examples of structure thereof, modifications whereof will be apparent to those skilled in the art, what is claimed as new is as follows:

Claims (25)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A shipping and installation restraining strap for a hydraulic actuator for operating a motor vehicle clutch, said hydraulic actuator forming part of an apparatus comprising a master cylinder, said hydraulic actuator and a conduit con-necting said master cylinder and said hydraulic acutator, said master cylinder, conduit and hydraulic actuator being prefilled with hydraulic fluid prior to installation on a motor vehicle, said hydraulic actuator having a housing and a linearly movable output member projecting from said housing, wherein said line-arly movable output member has an end connectable to an oper-ating member of a motor vehicle clutch and said strap holds said output member in a retracted position until after instal-lation of said hydraulic actuator on said motor vehicle, said strap comprising a retaining member having a configuration which is different from said strap and engages the end of said output member, a strip having an end attached to said retaining member, and means attaching the other end of said strip to a non-movable portion of the housing of said actuator, said strip being disposed substantially on the exterior of said housing, said strip having a portion of reduced strength between the ends of said strip whereby said strip is ruptured at said portion of reduced strength upon first operation of said motor vehicle clutch after installation of said prefilled master cylinder, conduit and hydraulic actuator on said motor vehicle.

2. The strap of Claim 1 comprising a pair of strips symmetrically arranged and each attached at an end to said retaining member.

3. The strap of Claim 2 wherein each of said strips has a retaining member on the end thereof, each of said retaining members has an aperture, and the end of said output member has a projecting portion disposed through said apertures.

4. The strap of Claim 1 wherein said portion of reduced strength comprises a portion of reduced width.

5. The strap of Claim 1 wherein said portion of reduced strength comprises a portion of reduced thickness.

6. The strap of Claim 5 wherein said portion of reduced strength further comprises a portion of reduced width.

7. The strap of Claim 2 wherein said means for attaching said strips to said housing comprises an annular flange on said housing and an annular flange collar at the other end of each of said strips, said flange collar having a flange portion abutting against said annular flange.

8. The strap of Claim 2 comprising a single retain-ing member, wherein said strips are attached to said retainer member at one end and each of said strips has at its other end means for attachment to a portion of the housing of said actuator.

9. The strap of Claim 8 wherein said attachment means comprises a strut integrally formed on said other end of each of said strips and a recess in said housing in which said strut is engaged.

10. The strap of Claim 8 wherein said attachment means comprises a lug integrally formed on said other end of each of said strips, and a flange on said housing having a pair of apertures, each of said lugs being passed through each of said apertures.

11. The strap of Claim 2 wherein said retaining member is a partially spherical cup member for fitting over the end of said output member, said output member having a corresponding spherical end portion.

12. The strap of Claim 2 wherein said retaining member has a bore provided with an end surface, and said output member has an end face engageable with said surface.

13. The strap of Claim 2 wherein said retaining member forms a bearing surface between said output member and an actuated mechanism.

14. The strap of Claim 1 wherein said strap is made of plastic.

15. The strap of Claim 2 wherein said strap is made of plastic.

16. The strap of Claim 13 wherein said strap is made of plastic.

17. The strap of Claim 2 further comprising means removably attaching an end of said strips to said retaining member.

18. The strap of Claim 17 wherein said means removably attaching an end of each of said strips to said retaining member comprises a strut integrally formed at the end of each of said strips, and a bifurcated ear integrally formed at the periphery of said retaining member, said ear having a recess for engage-ment by said strut.

19. The strap of Claim 17 wherein said means removably attaching an end of each of said strips to said retaining member comprises a radially extending flange on said retaining member and a ring integrally formed at said end of each of said strips, said ring being engaged over the periphery of said retaining member in abutment with said flange.

20. The strap of Claim 17 further comprising a disc-shaped flange integrally formed radially about the peri-phery of said retaining member.

21. The strap of Claim 17 wherein said retaining member is in the form of a cylindrical cap fitted on the end of said output member and having a substantially hemispherical portion, and an element operated by said actuator has a par-tially shperical concave recess engaged by said hemispherical end portion.

22. The strap of Claim 21 further comprising a disc-shaped flange integrally formed radially about the periphery of said cylindrical cap, said flange having an edge resiliently engaging said element beyond the edge of said concave recess.

23. A method of shipping and installing a hydraulic actuator for operating a motor vehicle clutch, said hydraulic actuator forming part of an apparatus comprising a master cylinder, said hydraulic actuator and a conduit connecting said master cylinder and said hydraulic actuator, said hydraulic actuator having a housing and a linearly movable output member projecting from said housing, wherein said linearly movable output member has an end connectable to an operating member of a motor vehicle clutch, said method comprising restraining said output member in a retracted position by means of a strap com-prising a strip having an end, providing said strip with a por-tion of reduced strength, attaching said strip to said housing such that said strip is disposed substantially on the exterior thereof, prefilling said apparatus with hydraulic fluid prior to shipment of said apparatus, and installing said apparatus on a motor vehicle while maintaining said output member of said hydraulic actuator in said retracted position by means of said strap, whereby said strip is caused to break and free said output member upon first actuation of said apparatus after installation on a motor vehicle.

24. The method of Claim 23 wherein said strap has a pair of symmetrically disposed strips.

25. The method of Claim 24 wherein said hydraulic fluid in said actuator is at a pressure higher than atmospheric pressure.