APPEAL from the Circuit Court of Cook County; the Hon. GEORGE
J. SCHALLER, Judge, presiding.
MR. PRESIDING JUSTICE SULLIVAN DELIVERED THE OPINION OF THE COURT AS MODIFIED UPON DENIAL OF PETITION FOR REHEARING:
Defendant appeals from a judgment on a verdict for damages of $69,800 entered in plaintiff's favor. Plaintiff, as subrogee for its insured, Charles Machine Works, Inc. (Charles), had sued defendant, the manufacturer of a hydraulic pump which was a component part of a work platform manufactured by Charles, for monies paid in settlement as the result of an action brought by American Glass Co. and six of its employees for injuries sustained while using the work platform.
Charles manufactures a hydraulic work platform marketed under the name of a "Skywitch." This platform elevates workmen and material to heights of up to 24 feet. Lifting is accomplished by an electric motor which powers two cylinders with piston rods driven by the hydraulic pump. The lifting device contains two safety features designed to prevent the platform from lifting when overloaded or blocked by an obstruction. The first of these safety features is the electric motor which powers the hydraulic pump and it "engages" at the beginning of the lifting process when the weight load capacity of the particular model is exceeded. Should there be excess weight, the motor "cuts out", shutting off power to the hydraulic pump and thus preventing the elevation of the platform.
The second safety feature is the defendant's hydraulic pump unit which becomes operative in the event the platform, once it begins its ascent, becomes overloaded gr encounters an obstruction or impediment. The hydraulic pump contains a relief valve, which is preset to respond to the amount of pressure introduced into the system, and when the amount of hydraulic pressure needed to sustain the lifting movement exceeds the setting on the relief valve, the valve activates and releases oil into a reservoir, so that it no longer flows into the cylinders. This release relieves the pressure on the piston rods and causes the platform to cease elevating.
In January, 1961, Charles purchased eight hydraulic pump units from the defendant, all of which were to have the relief valve preset at 2000 pounds per square inch ("psi"), thereby providing for the relief valve to engage whenever the amount of pressure in the hydraulic system exceeded 2000 psi. *fn1 The record indicates that defendant was familiar with the Skywitch and the nature of its normal uses.
Defendant's pump was installed by Charles in the Skywitch involved herein. The subject Skywitch had a lifting capacity of 2000 pounds, was 21 feet in length, elevated to a height of 24 feet, was 5 feet wide, weighed approximately 6000 pounds and stood 6 feet high in its lowered position. It was equipped with removable guardrails which fitted into sockets on the side of the work platform, four leveling jacks and two outriggers used for leveling and stabilizing the unit, and was mounted on four rubber tires.
Charles did not perform any tests on the hydraulic pump purchased from defendant, but did test the Skywitch after assembly. The record reveals that Charles, by its foreman, loaded the Skywitch up to its rated capacity (2000 pounds), raised and lowered it two or three times and stopped it at intermediate positions.
In February, 1961, the subject Skywitch was delivered to Murphy's Contractors Equipment (Murphy), Charles' distributor, who in turn sold the Skywitch to the American Glass Co. (American). Upon receipt from Charles, Frank Murphy, president of Murphy, ran the platform up and down and delivered the Skywitch to American on the following day.
American purchased the Skywitch to use in the installation of glass at two terminal buildings at O'Hare Airport. American intended to use the Skywitch to lift their workmen and materials alongside the exterior portions of the terminal. Upon receipt of the Skywitch, American placed an aluminum scaffold, which consisted of three sections and weighed approximately 500 pounds, on top of the work platform. In addition to the scaffold, American placed eight to ten men on the platform and raised and lowered the platform approximately four times. According to the testimony of American's engineer, the unit worked satisfactorily. Prior to this testing, American's engineer discussed the intended use of the Skywitch with, among others, the president of Charles and Frank Murphy and decided to utilize the scaffold on the Skywitch only after receiving their assurances that this plan was feasible. Additionally, there was uncontradicted opinion testimony by the president of Charles that, in the absence of additional base support, the risk of the Skywitch toppling over increased in proportion to the amount of additional weight added to it.
In March, 1961, American transported the Skywitch to the job site at O'Hare Airport and reassembled the scaffolding on the work platform of the Skywitch. The Skywitch was used without incident for 3 days. On the fourth day of its use the Skywitch collapsed, injuring the workmen on it. The following testimony was adduced with respect to that accident: The Skywitch was placed on wooden planks, approximately 2 to 6 inches from the building as measured by the second floor which, because of the extension of the second floor ledge, was 4 to 5 feet away from the base of the building. The outriggers were apparently placed down, although Charles' president testified that when he observed the Skywitch the following day, the outriggers were down on only one side. Six workers boarded the scaffold while the Skywitch was fully retracted and, in addition to the weight of the scaffold and these workers, two pieces of glass, weighing approximately 100 pounds, were added. This brought the total weight on the Skywitch to approximately 1750 pounds, well within the rated weight capacity of the Skywitch (2000 pounds). The motor was turned on and the platform, with scaffold, workers and glass, began to ascend. When it reached halfway to the second floor, it stopped and remained motionless for 5 minutes, apparently because of an electrical problem. Thereafter, the platform continued its climb until it reached within a foot of the working level and then suddenly collapsed in accordion-like fashion injuring the workmen.
Charles' president visited the site on the following day and found the Skywitch covered with a tarpaulin. He testified that he observed the two cylinder rods which extend the platform were bent in a "U" shape and also that the top deck of the platform was "deformed." In addition, he found a small aluminum shaving or chip on the Skywitch, and he then noticed that an aluminum column of the building directly above the left corner of the Skywitch had a 6- or 7-inch gouge in it about 20 feet above ground level. The gouge was deeper at its top than at the bottom. He concluded that the gouge was made by the Skywitch while it ascended. Subsequent testing revealed that the aluminum chip found by Charles' president could have come from the gouged column and that the paint particles found on the chip matched the paint on the Skywitch.
The Skywitch was transported from O'Hare Airport to American's parking lot, where it was once again covered with a tarpaulin. In May, 1961, the Skywitch was examined in the parking lot by representatives of the parties involved in a lawsuit arising out of the accident. This group included three engineers, a representative of American, and the president of Charles. Their trial testimony indicated that the Skywitch was in the same condition it had been in on the day following the accident. At this examination, the bent piston rods were removed and various measurements and observations were made with respect to them, as well as the rest of the Skywitch.
The Skywitch remained covered in American's lot and was next examined in January, 1966. Testimony indicated that the electric motor and hydraulic pump appeared to be in the same condition as when last observed in 1961. After testing the cylinder and piston rods, other tests were run on a similar Skywitch unit. The purpose of these other tests were said to be threefold: first, to perform a stress analysis of the Skywitch; second, to test the Skywitch with an overload; and third, to duplicate the 1961 accident. The stress analysis test consisted of running the Skywitch under different loading conditions and measuring the amount of stress present in the piston rods. The overload test was done by loading the platform with 3000 pounds, 1000 pounds over its rated capacity. When the platform began to rise, the motor cut out and would not lift the load.
In an effort to duplicate the 1961 accident, a similar Skywitch was loaded eccentrically with 2000 pounds (the weight on the platform being distributed unequally) and one corner of the platform being restrained so that it could not raise over 16 feet. When the platform reached the 16 foot mark and could go no further, the hydraulic pressure reached 2200 psi. The relief valve within the pump then began to operate so that the hypdraulic pressure remained the same, and the Skywitch remained stationary, indicating that the properly set relief valve operated to minimize the amount of pressure transmitted to the cylinder and piston rods.
After this test, the experts went to the American yard to test whether the hydraulic system on the subject Skywitch would relieve the pressure at 2000 psi, the presetting requested by plaintiff. The experts testified that to their knowledge the hydraulic pump was in substantially the same condition as when they last saw it in 1961. They then tested the electric motor and pump with a pressure gauge and found the readings went as high as 4300 psi. Following this, the relief valve was removed from the pump, and the experts noted that the seal placed on the valve at the defendant's factory was unbroken. Further, verification tests were run on the pump and the relief valve by the use of an accumulator *fn2 and these tests showed that the relief valve did not operate when the pressure reached as high as 3600 psi. One of the testing experts testified that in his opinion the hydraulic relief valve was not set to limit the pressure at 2000 psi. Moreover, at trial, one of the testing experts in response to a hypothetical question, opined that the collapse of the Skywitch was caused by its engaging the aluminum column of the terminal building during the ascendancy of the Skywitch which, in conjunction with the failure of the relief valve to minimize the excess hydraulic pressure (over 2000 psi) generated as the result of meeting the column, caused the bending of the piston rods. He further testified that the piston rods would not have failed with a pressure of only 2000 psi introduced into the system.
After the last series of tests, plaintiff tendered and defendant refused the defense of the pending action against plaintiff's insured. Eventually, plaintiff settled the suit of American and the injured workmen for $69,800 and thereafter filed this action seeking indemnity. The complaint was premised on the alternative theories of breach of warranty, strict liability and negligence. At the close of plaintiff's case and after a denial of defendant's motion for a directed verdict, the case was submitted to the jury, which returned a verdict for the plaintiff and awarded damages in the amount of $69,800.
Thereafter, defendant filed a post-trial motion seeking either a judgment notwithstanding the verdict or to set aside the verdict and judgment, or a new trial. After the denial of the ...