with reference to the annexed drawings the preferred embodiments of a weight lifting simulator apparatus according to the present invention will be herein described for indicative purpose and by no means as of limitation . although the following description describes the use of primary and secondary pneumatic cylinders , any elastic behavior load resistant members , such as elastic springs or the like , could be considered without departing from the scope of the present invention . referring first to fig1 to 4 there is shown a generally rectangular frame 2 of a weight lifting simulator apparatus 1 , a guideway 4 , or arm , being pivotally mounted thereon at pivot 6 on a side limb 8 thereof for rotation about a pivot axis between two limit angular positions ( one position limiting stopper being the piston rod 18 fully retracted inside the cylinder 14 as detailed hereinbelow and shown in fig2 , 4 , 7 , 8 and 9 , the other being shown in fig9 in dotted lines ). the free end of the guideway 4 remote from its pivot 6 either pivotally carries a block - and - tackle arrangement diagrammatically depicted at 10 , the arrangement 10 being connected to a suitable actuating handle 5 ( see fig5 ) via a rope or cable 12 , or is provided with a longitudinal extension 4 ′ and handle 5 ′ ( shown in dotted lines in fig1 ) of the guideway 4 away from the pivot 6 , for a user . a primary load resistant member , typically a pneumatic cylinder 14 is movably , preferably pivotally , mounted at a first primary end 16 on the frame 2 as illustrated with its primary second end or piston rod 18 pivotally carrying a clamp 20 , adjacent pivot 19 , for registration with the guideway 4 at any desired and selected position therealong . in this embodiment , twin secondary load resistant members , typically pneumatic cylinders 30 are provided and have a first secondary end pivotally attached to a collar 32 for pivotal connection with and adjacent the end of the piston rod 18 . the second secondary ends or piston rods 34 of the cylinders 30 are attached or connected , either fixedly or movably ( see fig1 a to 11 d and corresponding details hereinbelow ) and typically pivotally mounted , to a yoke in the form of a slider 36 bridging the guideway 4 and being slidable therealong , typically using a linear type bearing or the like . a pivot axis 35 of the secondary piston rods 34 is generally perpendicular and typically as close as possible to the sliding axis of the slider 36 for increased smoothness in the sliding motion , as shown in fig1 through 9 . preferably , the pivot axis 35 generally intersects the sliding axis of the slider 36 . in operation , the slider 36 allows the secondary cylinders 30 to remain substantially perpendicular to the guideway 4 during pivotal displacement thereof . the primary and secondary cylinders 14 , 30 are typically fluidly interconnected , to generally keep all internal pressures uniform , by suitable hoses 40 which typically unite in a pressure control or fill / purge valve 42 , such as a typical bicycle fill valve or the like , to eventually allow selective modification of the total amount of fluid , or fluid pressure , inside the cylinders 14 , 30 . the filling of the cylinders 14 , 30 could be performed via a conventional manually or power activated pump . obviously , more sophisticated pump mechanisms with predetermined pressure levels could also be considered without departing from the scope of the present invention ; the more fluid there is inside the cylinders the more resistive the created force will be . as shown in fig1 the apparatus 1 has the guideway 4 in its maximum upward angular displacement or extension such that the primary cylinder 14 has had its piston as “ fully extended ” as possible by a user employing the block - and - tackle 10 and the rope 12 , which is accordingly taut . the cylinder 14 , which obviously still has a minimum volume of air therein , is in a heavy load simulation with the clamp 20 secured near the free end of the guideway 4 and the slider 36 of the secondary cylinders 30 having moved towards side limb 8 with their collar 32 locked to the rod 18 to remain substantially perpendicular to the guideway 4 . this relative movement occasions free fluid interflow between the primary and secondary cylinders 14 and 30 thereby distributing the resistive force and providing a generally constant resistance to the user . depending on the weight of the slider 36 , the sliding displacement of the secondary cylinders 30 along the guideway 4 dynamically increases the weight inertial effect of the load simulator ; i . e . the relatively small dynamic load reduction felt by the user , as would be naturally felt with a real weight being lifted , will be larger if the displacement speed of the slider 36 induced by the rotational displacement of the guideway 4 is larger . fig2 shows the cylinder 14 in a contracted ( seating ) position corresponding to a resting configuration of the apparatus 1 ensured by the built - in pressure inside the cylinders . in the apparatus resting configuration , the rope or cable 12 is released by the return stroke of the user with the handle 5 ( as shown in fig5 ) up to an abutment position against a stopper or the like ( not shown ) that could also be the handle 5 itself or even protectors thereof that would be blocked by the first pulley it encounters or the like . the slider 36 of the secondary cylinders 30 has moved along the guideway 4 towards the block - and - tackle 10 , and this reciprocating movement is repeated as the user moves the rope 12 into a heavy load and then into a return or release position . fig3 and 4 show the clamp 20 in a different position nearer to the pivot 6 of the guideway 4 with the rod 18 extended to a smaller extent than in fig1 and 2 . the close position of the clamp 20 provides for a smaller lever length to the cylinder 14 on the guideway 4 , associated with a smaller range of travel of the piston in the primary cylinder 14 , give a lower resistance weight loading simulation . again , the interflow of air between the cylinders with the sliding of the piston rods 34 on the guideway 4 provides for a balancing of force that gives a smooth and constant application of load resistance with dynamic weight inertia effect . referring now to fig5 and 6 , the primary cylinder 14 is pivotally attached to an upper region 50 of the apparatus 1 and the guideway 4 is pivoted at 6 in a relatively lower region 51 of the apparatus . the clamp 20 is in the form of a spring - loaded detent 52 registering and engaging with a rack 54 of arcuate form provided in a slot 56 within the guideway 4 . the detent 52 is actuable by means of a wire or cable 58 and accordingly resetting the detent 52 in a recess of the rack will change the resistance loading of the primary cylinder 14 as with the first embodiment of fig1 to 4 . the clamp 20 is pivotally carried by an arm 53 which is attached to the piston rod 18 of the primary cylinder 14 . the slider 36 of the secondary cylinders 30 engages the guideway 4 in the manner shown in the drawings ; the secondary cylinders 30 are connected in a similar manner to a collar ( not shown ) pivotally mounted on the piston rod 18 . the guideway 4 carries at the free end remote from its pivot 6 a pulley 60 which is one of an array 70 of pulleys provided for the apparatus 1 as shown . the cable 12 is reeved around the pulley 60 and upon appropriate movement of the cable the guideway 4 is caused to pivot about its mounting at 6 . a pull on the cable causes tension therein and brings the guideway 4 into a downward path thus generating resistance via the compressed fluid in the primary and the secondary cylinders 14 , 30 which are balanced due to the fluid flow therebetween via the hoses 40 . the advantage of the arrangement is as previously indicated in relation to the first embodiment . however , the setting of the primary cylinder orientation relative to the guideway is fixed by virtue of the rack , which provides for predetermined incremental steps to give discrete modulation . with reference now to fig7 and 8 there is shown a variation on the embodiment illustrated in fig5 and 6 in that the guideway 4 is in two parts 4 a and 4 b generally parallel to each other ; the slot 56 is formed in each part and is of scalloped form on its relatively upper margin , each scallop 72 being so shaped as to accommodate a roller 74 carried on a yoke 76 which embraces both parts as more clearly can be seen in fig8 . a bridge piece 78 of the yoke 76 is mounted on the piston rod 18 also connected to a collar 80 mounted thereon . a fixed collar 82 is provided on the cylinder 14 and carries an actuating lever 84 with a cam 86 that abuts the collar 80 when the apparatus 1 is in the resting configuration with primary cylinder 14 in a substantially contracted configuration , rotation of the lever and thus the cam occasioning movement of the yoke 76 to engage or disengage the rollers 74 in a respective scallop 72 as desired to change the setting and to fix the rollers in the required setting . the slider 36 comprises spool type rollers 90 which engage the lower side of each of the parts 4 a and 4 b as can be seen in fig8 . as shown in fig7 and 8 , the pivot mounting 19 of the piston rod 18 would typically coincide with the axis of rollers 74 while the pivot 35 of the piston rods 34 would typically coincide with the rotation axis of the rollers 90 . the operation of this embodiment is essentially the same as that of the previous embodiment except that the setting of the primary cylinder is effected by the interengagement of the rollers 74 with the scallops 72 in contrast to the rack formation and the locking of the setting is secured by the use of a cam operated lever arrangement . fig9 depicts a variation of the embodiment of fig7 in terms of the connection mount between the primary and secondary cylinders 14 and 30 . the connection 100 provides for a linear displacement of the secondary cylinder ( s ) 30 relative to the rod 18 with a resilient bias giving a damping effect . in this connection , the connection 100 comprises a slideway bracket 104 , tightly secured to the rod 18 at 102 , holding a pin 106 on which the end 108 of the cylinder ( s ) 30 slides reciprocally , as shown by the straight arrow y , as much as possible in a frictionless manner , typically via a linear bearing or the like . a spring 110 is provided on the pin 106 and thus gives a bias to the end of the cylinder ( s ) 30 . obviously , the end 108 of the cylinder ( s ) 30 is pivotally mounted relative to the pin 106 as shown by arrow x . the pin 106 has its axis 107 ( linear movement axis ) that is typically angularly oriented towards the guideway 4 in a direction away from the pivot axis relative to the cylinder ( s ) 30 , or towards the free end of the guideway 4 when the latter is in its limit angular position away from the main cylinder 14 , as shown by angle t of fig9 with the limit angular position of the guideway 4 shown in dotted lines . obviously , when the angle t is properly set with the main piston rod 18 connected to the guideway 4 at its far most location relative to the pivot 6 ( in a heavy load configuration , not illustrated ), any other subsequent location of the piston rod 18 on the guideway 4 would be automatically set , with the effect of the connection 100 being the most apparent in that heavy load configuration where it is expected the most . the provision of the connection 100 is to further dynamically increase the weight inertial effect of the load simulator by increasing the simulation of the weight reduction feeling occurring during the lifting movement when lifting real weight bars , depending on the speed of the movement . the secondary cylinder ( s ) 30 always tends to remain generally perpendicular to the guideway 4 while contracting as much as possible , thus having the first secondary end or cylinder ( s ) 30 slide toward the spring 110 upon lifting movement because of the angle of the pin axis 107 . the biasing spring 110 is there to bias this displacement and prevent any shock that could occur , especially at the end of the linear displacement path along the pin 106 . typically , the angular position of the mount connection 100 relative to the piston rod 18 can be adjusted , preferably incrementally , via an adjustment mechanism 102 such as a tightening bolt or the like , to control the additional dynamic weight inertia effect of the apparatus 1 provided by this connection 100 . the overall advantage of the present invention is to simulate weight lifting apparatus by the use of pneumatic cylinders with free interflow of air thus facilitating the achievement of constancy in terms of resistance . referring more specifically to fig1 , there is shown another embodiment 1 a of the apparatus of the present invention in which the first primary end 16 of cylinder 14 is movably , typically slidably and non - pivotally , mounted on an arcuate guide rail 3 secured to the frame 2 . the guide rail 3 provides for circular displacement of the first primary end about a virtual pivot 16 ′ such that the primary load resistant member is virtually pivotally mounted on the frame . this mounting allow the use of a shorter primary cylinder 14 , yet with similar volume as the long primary cylinder of fig1 through 9 , i . e . similar reservoir , without affecting the weight lifting simulation characteristics of the apparatus 1 a . in order to vary the dynamic weight inertia effect of the apparatus 1 , the second secondary ends or piston rods 34 could be connected in different ways to the slider 36 , as shown in fig1 a through 11 d , as examples . in fig1 a , the rods 34 are fixedly mounted on the slider 36 via securing bolts 37 a to restrain the dynamic weight inertia effect from the sliding motion of the slider 36 . in fig1 b , the dynamic weight inertia effect is slightly enhanced by the rods 34 being slidably mounted , in a direction typically parallel to the slider displacement direction , on the slider 36 via a slot - square shaft arrangement 37 b or the like , the arrangement providing a smooth ( not jerked ) sliding . in fig1 c and 11 d , the rods 34 movably mounted on the slider 36 via flexible links , such as a rubber - type piece 37 c , a helical spring 37 d , respectively , or the like flexible arrangement , further enhance the dynamic weight inertia effect to the apparatus 1 from the sliding motion of the slider 36 . referring now to fig1 a , there is schematically shown the relative force fu required from a user to position the second primary end ( piston rod 18 ) of the primary cylinder assembly 14 along the guideway 4 away from a neutral position n , with the arcuate guideway slot 56 ( or any other arcuate guide or the like ) having a smooth upper margin 57 rollably engaged by the roller 74 whose pivot axis 19 is further a pin or the like that lockingly engages one of the different position holes 75 following a generally constant radii curve c about the first primary end pivot point 16 when leading away from the neutral position n wherein the primary and secondary cylinders 14 , 30 are generally parallel to one another ( as shown in dotted lines in fig1 a and 12 b ), since the secondary cylinder 30 tends to remain into the neutral position with force fs . this user applied force fu might get significant enough to prevent a young or weak user from locating the primary piston 14 in position holes 75 at either ends of the slot 56 . in order to reduce that amount of effort required by the user , illustrated by smaller force fu ′ in fig1 b , the guideway slot 56 ′ is preferably shaped with a gradually decreasing radii curve c ′, about the first primary end pivot point 16 , when leading away from the neutral position n , as illustrated in solid lines ( relative to dotted lines ) in fig1 b . this decreasing radii curved slot 56 ′, with corresponding position holes 75 ′, essentially compensates for the retention force fs exerted by the secondary cylinder 30 by allowing the primary cylinder 14 to contract while the secondary cylinder 30 , operatively or fluidly interconnected to the primary cylinder 14 , is forced to expand and pulls with force fp while getting away from the neutral position n . depending on the design parameters ( actual angles and the like ), the force fp exerted by the primary cylinder 14 could happen to be slightly larger than the resistive force fs from the secondary cylinder 30 such that the user &# 39 ; s force fu ′ could be negative ( in the opposite direction than illustrated in fig1 b ). it is to be noted that the neutral position n could be anywhere along the arcuate guide , or even away therefrom ( virtually out of the guideway 4 ), and not necessarily at its geometrical center . also , as it would be readily understood by one skilled in the art , the gradually decreasing radii curve c ′ could be formed with a constant smaller radii about a point located closer to the guideway 4 than the first primary end pivot point 16 . although the above description refers to resistance provided by pull - type cylinders ( or other pull - type load resistant members ), it would be obvious to one skilled in the art to use push - type cylinders ( or other push - type load resistant members ) without departing from the scope of the present invention . in order to further control the dynamic weight inertia effect response of the apparatus 1 , some weight ( not shown ) could be selectively added / removed to the slider 36 or rollers 90 of fig1 to 4 since the gravity effect works in the same direction as the sliding movement direction of the secondary second end or piston rod ( s ) 34 on the guideway 4 . additionally , when the guideway 4 is below the cylinders 14 , 30 as in fig5 to 9 , some hanging weight w or the like biasing force ( as shown in dotted lines in fig7 ) could be even connected to the slider 36 to reorient the resulting gravity effect in the same direction as the sliding inertial effect of the piston ( s ) 34 on the guideway 4 by counteracting the direct effect of gravity on the slider 36 that would otherwise tend to generate some shuddering of its sliding movement . although the present weight lifting simulator apparatus has been described with a certain degree of particularity , it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein , but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed .
weight lifting simulator apparatus includes a primary pneumatic cylinder providing the principal resistance for simulating weight lifting exercise with at least one secondary cylinder in free fluid interconnection with the primary cylinder whereby constant and balanced loading is achieved , with provisions for dynamic simulation of weight inertia effect , and control thereof , as in lifting a real weight . the primary and the secondary cylinders are associated with a guideway , the primary cylinder being fixed to the guideway and the secondary cylinder being slidable relative to the guideway and pivotable relative to the piston rod of the primary cylinder . variation of the securement position of the primary cylinder on the guideway is available and valving is provided in the fluid interconnection .