CARLEY, Chief Judge.

Appellant-plaintiff slipped and fell while ascending an escalator located in a store owned by appellee-defendant Sears Roebuck Company (Sears). The escalator had been designed, installed, and maintained by appellee-defendant Montgomery Elevator Company (Montgomery). Appellant brought an action against appellees, seeking to recover for the personal injuries she allegedly sustained in her fall. The case was tried before a jury. At the close of appellant's evidence, both appellees moved for a directed verdict. The trial court granted the motions and appellant appeals.

1. Viewed in the light most favorable to appellant, the evidence adduced at trial shows that she fell backward while ascending the escalator. She testified that her fall was caused by a malfunction of the moving handrails. According to appellant, the left handrail stopped moving, but the right handrail continued to move and, as she held onto both the moving and the non-moving handrails, she was twisted around and back and lost her balance. Appellant's husband had ascended the same escalator some ten or fifteen minutes earlier and had had a similar experience which nearly caused him to lose his balance. He testified that, after his experience, he informed an employee of appellee Sears of the malfunctioning escalator.

Appellant concedes that, as against appellee Montgomery, she adduced no direct evidence of any negligent act or omission in the design, installation or maintenance of the escalator. She urges, however, the principle of res ipsa loquitur was applicable and that the trial court therefore erroneously directed a verdict in favor of appellee Montgomery.

"`Negligence is not to be presumed, but is a matter for affirmative proof. [Cits.]....'" Worth v. Orkin Exterminating Co., 142 Ga. App. 59, 62 (3) ( 234 S.E.2d 802) (1977). "`The expression "res ipsa loquitur" means that the transaction speaks for itself. It is a rule of evidence which allows an inference of negligence to arise from the happening of an event causing an injury to another where it is shown that "the defendant owned, operated, and maintained, or controlled and was responsible for the management and maintenance of the thing doing the damage" and "the accident was a kind which, in the absence of proof of some external cause, does not ordinarily happen without negligence." [Cit.] The rule is one of necessity in cases where there is no evidence of consequence showing negligence on the part of the defendant. [Cits.]'" Housing Auth. of Atlanta v. Famble, 170 Ga. App. 509, 525 (3b) ( 317 S.E.2d 853) (1984). However, the evidence in the instant case "does not authorize the application of the doctrine ... for the reason that mechanical devices, such as the one here involved, get out of working order, and sometimes become dangerous and cause injury without negligence on the part of anyone. Any other ruling would make the occupier of premises an insurer. The principal basis for application of the rule of res ipsa loquitur is that the occurrence involved would not have occurred [but for] negligence, and [this] negligence [may properly be] charged to the person in exclusive control of the instrumentality. [Cits.]" Quick Shops v. Oldham, 100 Ga. App. 551, 556 (1) ( 111 S.E.2d 920) (1959). See also Darlington Corp. v. Finch, 113 Ga. App. 825, 827 ( 149 S.E.2d 861) (1966). Since the malfunction in the escalator certainly could have resulted without any negligent act or omission on the part of anyone, the principle of res ipsa loquitur is inapplicable. See generally Hospital Auth. of St. Marys v. Eason, 222 Ga. 536, 541 (1) ( 150 S.E.2d 812) (1966). There being no evidentiary basis upon which the trior of fact could have found fault on the part of appellee Montgomery, the trial court correctly directed a verdict in its favor. See Johnson v. Dallas Glass Co., 183 Ga. App. 584, 586 (1) ( 359 S.E.2d 448) (1987).

2. Pretermitting a lack of evidence as to the cause of the purported malfunctioning of the escalator, appellee Sears, as the owner of the premises, may nevertheless be held liable for the injuries that appellant sustained if it had superior actual or constructive knowledge of the existence of that malfunction and failed to exercise ordinary care either to correct the problem or to warn appellant of it. See generally OCGA § 51-3-1; Rogers v. Eckerd Drugs, 149 Ga. App. 788, 789 (1) ( 256 S.E.2d 130) (1979).

If the evidence showed only that the escalator had been malfunctioning for a ten-to-fifteen-minute period prior to appellant's fall, a recovery based upon appellee Sears' constructive knowledge would not be authorized. See generally Mazur v. Food Giant, 183 Ga. App. 453 (1) ( 359 S.E.2d 178) (1987). The evidence shows, however, that, during that period of time, appellee Sears had actual knowledge that its escalator was malfunctioning. The evidence would authorize a finding that appellant's husband had informed an employee of appellee Sears of the malfunctioning escalator some ten-to-fifteen minutes before appellant fell. We cannot say that a landowner who has actual knowledge for a ten-to-fifteen-minute period that an escalator on its premises is malfunctioning is, as a matter of law, not negligent when it fails either to correct that potentially dangerous condition by stopping the malfunctioning escalator or otherwise, in the alternative, to warn its patrons of the existence of the potentially dangerous condition. "Under [OCGA § 51-3-1] the owner or occupier of the land is liable in damages to those expressly or impliedly invited upon the premises for such damage as is occasioned by his failure to exercise ordinary care to keep the premises and approaches safe. Ordinary care or diligence is defined in [OCGA § 51-1-2] as that degree of care which is exercised by ordinarily prudent persons under the same or similar circumstances. A legion of decisions by this court [has] pronounced the rule that questions of negligence and diligence are ordinarily referred to the jury for settlement. Thus, such questions are for the jury, and the courts will decline to solve them ... except in plain, palpable, and indisputable cases. [Cits.] Where reasonable minds might disagree as to whether the alleged acts [or omissions] constitute an action of negligence, a question for the jury is presented. [Cit.] Negligence is a question particularly for the jury. [Cit.]" Knowles v. LaRue, 102 Ga. App. 350, 352 ( 116 S.E.2d 248) (1960).

Appellee Sears makes a "right for any reason" argument based upon the following alternative ground which was raised in, but rejected by, the trial court as a basis for the grant of the motion for a directed verdict: "[N]ot a single doctor testified that he could tell with any degree of medical certainty that [appellant] sustained any injury from this alleged fall. So [appellee Sears'] contention ... is that there is no competent evidence whatsoever that she sustained any injury from this alleged fall." According to appellee Sears, this alternative ground was meritorious and would render the trial court's grant of its motion for a directed verdict a correct ruling. A review of the record shows, however, that this alternative ground was without merit and would not have authorized the grant of appellee Sears' motion for a directed verdict. See generally National Dairy Prod. Corp. v. Durham, 115 Ga. App. 420 ( 154 S.E.2d 752) (1967).

3. Appellant enumerates as error the exclusion of testimony by an employee of appellee Sears. The record clearly shows that this witness had no personal knowledge of any fact relevant to appellant's fall or to appellee Sears' liability. Accordingly, the trial court did not err in excluding the irrelevant testimony.

4. The grant of a directed verdict in favor of appellee Montgomery is affirmed. The grant of a directed verdict in favor of appellee Sears is reversed.

Judgment affirmed as to appellee Montgomery and judgment reversed as to appellee Sears. McMurray, P. J., Banke, P. J., Birdsong, Pope and Benham, JJ., concur. Deen, P. J., Sognier and Beasley, JJ., dissent.

CARLEY, Chief Judge.

DECIDED DECEMBER 4, 1989.