fig1 illustrates a shower curtain tension rod 10 in accordance with an embodiment of the present invention . the tension rod 10 includes a hollow stationary rod 12 and a hollow telescoping rod 14 having a slightly smaller outer diameter than the inner diameter of the stationary rod 12 . the telescoping rod 14 is axially movable with respect to the stationary rod 12 . the stationary and telescoping rods 12 and 14 may be made of any suitable material , such as metal or the like . a cylindrical bushing 16 made of plastic or other suitable material is partially inserted inside the end of the stationary rod 12 with a portion extending therefrom and surrounding the telescoping rod 14 . the overall length of the tension rod 10 may typically range from 24 to 90 inches . as shown in fig1 , an adjustable end cap 20 is mounted on an end of the telescoping rod 14 , while a stationary end cap 60 is mounted on end of the stationary rod 12 . alternatively , the adjustable end cap 20 could be mounted on the end of the stationary rod 12 . as more fully described below , each of the end caps 20 and 60 has a disk - shaped contact member 58 and 64 , respectively , which contact the walls of the bath or shower stall ( not shown ) in which the shower curtain tension rod 10 is mounted . fig2 illustrates the adjustable end cap 20 in a partially extended position in which the threaded portion 34 of a bolt secured in the adjustable end cap 20 is threadably engaged in a threaded hole 18 at the end of the telescoping rod 14 . in fig3 , the adjustable end cap 20 has been disengaged from the telescoping rod 14 by unscrewing the threaded portion 34 from the threaded hole 18 . although the adjustable end cap 20 is threadably mounted on the telescoping rod 14 by means of the threaded bolt 34 in fig2 and 3 , it is to be understood that any other suitable threaded arrangement may be used in accordance with the present invention , including a threaded portion integrally formed with the remainder of the end cap 20 , or the use of a threaded nut or threaded hole in the end cap 20 and a threaded shaft extending from the end of the telescoping rod 14 . fig4 is an exploded view showing the components of the adjustable end cap 20 . the adjustable end cap 20 includes a generally cylindrical cap body 22 , a threaded bolt 30 , a retainer 40 and a rotatable end disk 50 . the bolt 30 includes a head 32 and threaded portion 34 . although a hex - head bolt is shown , it is to be understood that any other suitable bolt or mechanical fastener design may be used in accordance with the present invention . as more fully described below , the bolt 30 is held in a stationary position in relation to the cap body 22 . the various components of the end cap 20 may be made of any suitable materials such as plastic , metal and the like . for example , the cap body 22 may be made of polypropylene and the bolt 30 may be made of metal . fig5 - 8 illustrate details of the cap body 22 of the adjustable end cap 20 . fig5 and 6 show the outermost end of the cap body 22 , while fig7 and 8 show the opposite end of the cap body 22 that is located adjacent to the telescoping rod 14 when the tension rod is assembled . as shown in fig6 and 7 , a hexagonal bolt head holder 24 in the form of a recessed hexagonal pocket is provided at the center of the cap body 22 . the holder 24 includes a central opening 25 through which the threaded portion 34 of the bolt 30 passes . support arms 26 extend between the interior surface of the generally cylindrical cap body 22 to the exterior surface of the holder 24 . three openings 27 are provided in corresponding sides of the hexagonal holder 24 to provide engagement edges for the finger clips 44 of the retainer 40 . after the head 34 of the bolt 30 mounted inside the hexagonal holder 24 , the retainer 40 is inserted through the outside end of the cap body 22 to thereby lock the bolt 30 in place . this is accomplished by the finger clips 44 , wherein the arms 45 flex radially outward as the retainer 40 is inserted in the cap body 22 until the locking tabs 46 of the finger clips 44 snap into place in the openings 27 for engagement with the holder 24 . in this manner , the retainer 40 is held in a stationary position and does not rotate or move in an axial direction with respect to the cap body 22 . as shown most clearly in fig4 and 9 - 11 , the retainer 40 includes a generally disk - shaped cylindrical body 42 with three finger clips 44 extending from one surface thereof . each finger clip 44 includes a flexible arm 45 and a locking tab 46 . as shown most clearly in fig4 and 10 , an annular projection with a central hole 48 is located at the center of the cap body 22 . the annular projection and hole 48 are used to rotatably mount the end disk 50 thereon , as more fully described below . as shown in fig4 and 1244 , the rotatable end disk 50 includes a support disk 52 made of relatively rigid material such as plastic or any other suitable material . for example , the support disk 52 may be made of polypropylene , polyethylene or the like . a mounting assembly 54 includes two flexible mounting fingers 56 that extend from the surface of the support disk 52 . an elastomeric contact disk 58 is secured to one surface of the support disk 52 by any suitable means such as adhesive . the elastomeric contact disk may be made of any suitable elastomeric material such as natural rubber , synthetic rubber , foam , resilient polymers and the like . the contact disk 58 may have a relatively high friction coefficient to help secure the tension rod 10 in position when it is installed in a bath or shower stall . fig1 is a side sectional view illustrating the rotatable mounting arrangement of the end disk 50 on the retainer 40 . in the position shown in fig1 , the flexible mounting fingers 56 of the end disk 50 have been inserted into the central hole 48 of the retainer 40 with their end tabs engaging the edge of the annular projection . in this position , the interior surface of the support disk 52 contacts the exterior surface of the retainer body 42 . however , the end disk 50 is rotatable around its central axis with respect to the retainer 40 because the flexible mounting fingers 56 of the mounting assembly 54 have a sufficient tolerance with respect to the central hole 48 of the annular projection of the retainer 40 , e . g ., a clearance space is provided between the inner surface of the central hole 58 and the fingers 56 , or any contact between the inner surface of the hole 58 and fingers 56 is of relatively minor force which permits the end disk to rotate . thus , while the rotatable end disk 50 may be snap - fit onto the retainer 40 , the fit is such that the end disk 50 is still able to rotate with respect to the retainer 40 . as will be appreciated , when the assembled retainer 40 and rotatable end disk 50 as shown in fig1 are installed inside the cap body 22 , the retainer 40 is held in a stationary position in relation to the cap body 22 while the end disk 50 is free to rotate with respect to the cap body 22 . fig1 is a side sectional view of the end portion of a stationary end cap 60 that may be mounted on the end of the stationary rod 12 in accordance with an embodiment of the present invention . the stationary end cap 60 includes a generally cylindrical body 62 having an elastomeric contact disk 64 mounted thereon . the elastomeric contact disk 64 may be held in a stationary position in relation to the body 62 . however , in a preferred embodiment , the elastomeric contact disk 64 is rotatable in relation to the body 62 of the stationary end cap 60 . a mounting projection 66 extends from the inner surface of the contact disk 64 . a mounting disk 68 having a central mounting hole 69 is secured to the body 62 of the stationary end cap 60 . sufficient tolerance may be provided between the cylindrical outer surface of the mounting projection 66 and the mounting hole 69 such that the contact disk 64 is free to rotate with respect to the body 62 of the stationary end cap 60 . the elastomeric contact disk 64 may be made of any suitable material such as natural rubber , synthetic rubber , foam , resilient polymers and the like . the contact disk 64 may have a relative high friction coefficient to help secure the tension rod 10 in position when it is installed . fig1 and 18 illustrate a torsional locking mechanism 70 for locking the stationary rod 12 and telescoping rod 14 together in a desired position in accordance with an embodiment of the invention . although not shown in fig1 and 18 , the torsional locking mechanism 70 mounted on the end of the telescoping rod 14 is positioned inside the stationary tube 12 when the tension rod 10 is assembled . the torsional locking mechanism 70 includes a locking pin 72 having a locking cam head 74 at the end thereof . the locking pin 72 is mounted on the end of the telescoping rod 14 by means of a support flange 76 having a central opening that receives the locking pin 72 . in the embodiment shown in fig1 and 18 , the pin 72 may reciprocate slightly into the rod 14 . a compression spring 78 surrounds the locking pin 72 and presses against the support flange 76 on the telescoping rod 14 and an annular flange 80 of the locking head 74 . the compression spring 78 thus forces the locking pin 72 axially outward from the telescoping rod 14 to provide tension for the shower curtain rod . the locking pin 72 reciprocates in the support flange 76 a relatively short distance , e . g ., less than about 0 . 5 inch , typically less than about 0 . 25 inch . in another embodiment , the pin 72 is fixedly mounted at the end of the telescoping rod , and the spring 78 is removed . such a non - reciprocating pin design provides a relatively rigid structure that may increase the holding power of the tension rod 10 . for example , the tension rod 10 may hold greater than 25 pounds of weight in comparison with prior spring designs that may hold only 15 to 18 pounds . the locking cam head 74 includes the annular flange 80 and an end flange 86 . the locking head 74 includes two cam surfaces 82 extending between the annular flange 80 and end flange 86 having non - circular , helical surfaces . one of the cam surfaces 82 is shown in each of fig1 and 18 , with the other cam surface located 180 ° around the circumference of the locking head 74 . the locking head 74 includes two stop surfaces 84 extending between the annular flange 80 and end flange 86 . each stop surface 84 lies substantially in a plane extending radially outward from the central axis of the locking head 74 and defining an interruption or transition between each of the cam surfaces 82 . as shown in fig1 , a locking cam sleeve 90 is mounted on the locking head 74 between the annular flange 80 and end flange 86 . as shown in fig1 and 20 , the locking cam sleeve 90 includes two cam members 92 , each of which has an inner cam surface 94 , an outer contact surface 96 and a stop edge 97 . the cam members 92 are connected together by a thin web 98 . the locking cam sleeve 90 may be made of any suitable flexible or elastomeric material such as natural rubber , synthetic rubber , flexible plastic or the like . the locking cam sleeve 90 preferably has a relatively high friction coefficient in order to help secure the telescoping rod 14 in a selected axial position with respect to the stationary rod 12 , as more fully described below . the torsional locking mechanism 70 operates as follows . the locking cam sleeve 90 is initially located in a radially retracted position on the locking cam head 74 in which the stop edges 97 of the sleeve 90 are in contact or adjacent to the corresponding stop surfaces 84 of the locking head 74 . the thicker portions of the cam members 92 are adjacent to the radially recessed portion of the cam surfaces 82 . in this radially retracted position , the telescoping rod 14 is free to move axially with respect to the stationary rod 12 . during installation , the telescoping rod 14 is extended from the stationary rod 12 to a desired position in which the rotatable end disk 50 and stationary end cap 60 are in initial contact positions against the bath or shower stall walls . in this position , the telescoping rod 14 is then twisted around its longitudinal axis , which rotates the locking cam head 74 inside the stationary rod 12 . upon such a twisting motion , the outer contact surfaces 96 of the locking cam sleeve 90 contact the inner surface of the stationary rod 12 and frictional forces therebetween hold the locking cam sleeve 90 in a stationary position with respect to the stationary rod 12 , i . e ., the locking cam sleeve 90 does not rotate inside the rod 12 with the remainder of the torsional locking mechanism 70 . as the locking cam head 74 rotates inside the stationary rod 12 with the locking cam sleeve 90 remaining in position , the inner cam surfaces 94 of the locking cam sleeve 90 slide in a generally circumferential direction on the cam surfaces 82 of the locking cam head 74 . due to this relative movement , the cam members 92 move radially outward and press against the inner surface of the stationary rod 12 with sufficient force to lock the cam head 74 into position within the stationary rod 12 . thus , the telescoping rod 14 and stationary rod 12 are held in position with respect to each other , and the only axial movement therebetween results from compression of the optional spring 78 . this embodiment permits a slight amount of axial movement between the telescoping rod 14 and stationary rod 12 against the force of the spring 78 . alternatively , in the embodiment in which the spring 78 is eliminated and the pin 72 is fixedly attached to the end of the telescoping rod 14 , essentially no axial movement occurs between the stationary and telescoping rods 12 and 14 . with the torsional locking mechanism 70 in the locked position , the adjustable end cap 20 may be rotated with respect to the telescoping rod 14 , thereby extending the adjustable end cap 20 into the installed position in which the shower curtain tension rod 10 is securely mounted in a bath or shower stall . the shower curtain tension rods of the present invention overcome the cumbersome installation associated with conventional tension rods . the rotatable end disk 50 on the adjustable end cap 20 prevents the tension rod from walking on the wall during installation . the internal torsional locking mechanism 70 provides improved stability . an important benefit of the tension rods of the present invention is much improved simplicity of installation . the result is an installation time of about 10 seconds or less versus approximately 1 minute with the existing products . furthermore , the present tension rods create a much quieter product due to the elimination of the long spring and screw mechanism used in existing products on the market . the present tension rods are also capable of holding more weight than conventional tension rods . the rods are suitable for residential use , hotels , hospitals and other institutions . whereas particular embodiments of this invention have been described above for purposes of illustration , it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims .
shower curtain tension rods comprising a stationary rod , movable rod and adjustable end cap are disclosed . the movable rod may telescope in the stationary rod and may be secured in an axially extended position with respect to the stationary rod . the adjustable end cap may be axially extended from the movable rod and / or stationary rod to provide greater holding force for the tension rod . the shower curtain tension rods may be installed quickly and easily in various sizes of bath and shower stalls .